Category Archives: Cell Biology

Cell Biology

In silico experiments of bone remodeling explore metabolic diseases and their drug treatment – Science Advances

INTRODUCTION

Bone structure and function are maintained by homeostatic load-adaptive remodeling, which generates sophisticated bone microarchitecture to satisfy mechanical demands. This adaptive mechanism is the object of strong scientific and academic interest (1, 2). In addition, maintenance of load-bearing function throughout life is important to prevent bone fractures. Bone homeostasis can be disrupted by an imbalance between bone resorption and formation due to disuse or sex hormone aberrations, resulting in metabolic bone diseases such as osteoporosis (3, 4). Thus, it is indispensable to fully elucidate the underlying molecular and cellular mechanisms of bone metabolism and remodeling, from both scientific and clinical viewpoints.

Recent advances in molecular and cellular biology have helped identify multiple signaling pathways that regulate osteoclastic bone resorption and osteoblastic bone formation, as well as their relationship to mechanical stress (57). For example, genetic modification of signaling molecules in vivo has illuminated the molecular mechanisms of bone diseases (8, 9). These advances have also accelerated the development of molecularly targeted drugs against bone diseases (1012). However, the physiological or pathological status of bone as a system remains difficult to predict because of the interplay among bone cells and because of the complexity of relevant signaling networks.

To effectively prevent and treat bone diseases through a full understanding of bone remodeling regulated by mechano-biochemical couplings, computer simulation approachesthe so-called in silico approachesare of great significance. A large number of in silico researches on bone remodeling have been conducted by focusing on its mechanical aspect (13), and although they could reproduce adaptive changes of the bone microstructure to external loadings, the used in silico models were based on various phenomenological hypotheses regarding cellular mechanism. Increasing knowledge on cell-cell interaction via complex signaling pathways has motivated the development of in silico models that describe bone cell dynamics by explicitly taking into account the involved intercellular signaling (1416). These models allow theoretical evaluation of a biochemical aspect of bone remodeling. However, they cannot account for the relationship between spatially organized bone structure and the underlying cellular activities. Hence, a novel in silico model to investigate spatial and temporal behavior of bone remodeling that results from mechano-biochemical couplings is required.

We now enable simultaneous spatiotemporal observation of mechano-dependent intercellular signaling, bone cell dynamics, and bone morphological change through an in silico experimental platform (V-Bone) that mathematically models bone remodeling and links microscopic molecular/cellular interaction to macroscopic tissue/organ adaptation. The proposed in silico model was qualitatively verified from both mechanical and biochemical viewpoints by reproducing bone adaptation to mechanical loading and metabolic bone diseases. To quantitatively show the validity of the in silico model, in silico perturbation of a specific signaling molecule was conducted to compare with corresponding in vivo experiments. After quantitative validation, the in silico model was applied to predict the therapeutic effects of various drugs against osteoporosis. This platform is a revolutionary approach to fully and noninvasively explore bone remodeling dynamics over time, at scales ranging from the molecule/cell to the tissue/organ in a living body. The platform may also accelerate a paradigm shift in studies of bone metabolism and remodeling.

We propose an in silico model to investigate bone remodeling by incorporating mechano-biochemical couplings. Although bone remodeling is regulated by both local signaling factors and systemic hormones (17), to highlight osteocyte-driven bone remodeling as a local event, the in silico model is based on the assumption that mechanosensitive osteocytes buried in the bone matrix orchestrate osteoclastic bone resorption and osteoblastic bone formation via local intercellular signaling, without considering systemic hormonal changes. In addition, this model is based on the hypothesis that osteocytes regulate bone resorption and formation to achieve a locally uniform stress/strain state via bone remodeling (18, 19), which means that bone remodeling is susceptible to the local spatial variation of stress/strain in the bone tissue rather than their magnitude. Considering that osteocytes in the bone matrix are believed to be stimulated by interstitial fluid flow (20), which is driven by the gradient of fluid pressure instead of the fluid pressure itself, this hypothesis would be reasonable and is validated through a theoretical study (21).

In particular, mechanically stimulated osteocytes embedded in the bone matrix at position x produce the mechanical signal Socy (eq. S1), which is the product of the density of osteocytes ocy and the modified equivalent stress ocy, as shown in Fig. 1A (see Supplementary Methods S1.1). Through intercellular communication, the cell located on the bone surface at xsf integrates the local mechanical signals Socy within the neighboring region into Sd (eq. S3), which means the weighted average of Socy in . Ultimately, bone remodeling depends on the mechanical information Sr (eq. S5), a measure of local nonuniformity of stress defined by the ratio of Socy to Sd.

(A) Model of mechanosensing by osteocytes. Osteocytes produce mechanical signals Socy in response to a mechanical stimulus, defined as the modified equivalent stress ocy (eq. S2 in Supplementary Methods S1.1), and transmit these signals to bone surface cells. Sr is a critical mechanical information that influences bone remodeling and is assumed to be the ratio of Socy to Sd, the latter being the average Socy over the region . (B) Intercellular signaling for bone remodeling as incorporated into the bone remodeling platform (V-Bone). (C) Formulation of the spatial and temporal behavior of signaling molecules. The concentration of each signaling molecule i is varied according to the reaction-diffusion equation, which includes production, degradation, diffusion, and reaction terms. (D) Probability of cell genesis, i.e., differentiation from precursor cells and proliferation and apoptosis for osteoclasts (pgenocl, papoocl) and osteoblasts (pgenobl, papoobl). These are regulated by the concentration of RANKL (RNL), Sema3A-Nrp1-PlxnA complex (SNP), sclerostin (SCL), and the mechanical information Sr, and can be described by Hill-type activator/repressor functions.

In response to mechanical stimuli, osteocytes activate or repress the activities of osteoclasts and osteoblasts through complex signaling cascades (see Supplementary Methods S1.2). An overview of intercellular signaling incorporated in the in silico model is presented in Fig. 1B. Sclerostin, a well-known mechanoresponsive protein in osteocytes that plays an important role in bone remodeling, inhibits osteoblastogenesis by binding to LRP5/6 and blocking canonical Wnt signaling and induces osteoblast apoptosis (6, 22). Production of sclerostin from osteocytes is reduced by mechanical loading (17, 22). On the other hand, the RANK/RANKL/OPG axis is primarily responsible for osteoclastogenesis. Osteoclast differentiation is induced by binding of receptor activator of nuclear factor- (RANK), which accumulates at the membrane of osteoclast progenitors, to RANK ligand (RANKL) produced by mesenchymal cells such as osteoblasts and osteocytes (6, 7, 23). In contrast, osteoprotegerin (OPG) released from mesenchymal cells inhibits osteoclast differentiation by sequestering RANKL (7, 12). Semaphorin 3A (Sema3A) inhibits osteoclast differentiation but promotes osteoblast differentiation by binding to a receptor complex consisting of neuropilin-1 (Nrp1) and one of the class A plexins (PlxnA) (24).

The spatial and temporal behavior of each signaling molecule is modeled as shown in Fig. 1C, where the concentration of signaling molecule i, i, varies according to the reaction-diffusion equation (eq. S8, see Supplementary Methods S1.3). The first, second, and third terms denote production, degradation, and diffusion of molecule i, respectively, while the last term describes the reaction of molecule i with molecule j, such as in ligand-receptor interaction (1416). We modeled mechano-biochemical coupling by describing the production rate of sclerostin PSCL as a monotonically decreasing function of the mechanical information Sr (eqs. S10 and S11), based on the experimental finding that Sost/sclerostin levels were reduced with increasing strain magnitude (25).

Bone remodeling is a cyclical process of bone resorption by osteoclasts and bone formation by osteoblasts (6, 7, 26). To express the initiation and termination of this cycle, the probability of cell genesis (i.e., differentiation from precursor cells and proliferation) pgeni and apoptosis papoi for bone surface cell i (i = ocl or obl) was modeled as a function of the concentration of signaling molecules (eqs. S24 to S27, see Supplementary Methods S1.4). As shown in Fig. 1D, the probability of osteoclastogenesis increases with the RANKL concentration but decreases with increasing Sema3A concentration. On the other hand, osteoblastogenesis increases with the Sema3A concentration but decreases with increasing sclerostin concentration. The probability of osteoblast apoptosis increases with the sclerostin concentration. An increase in mechanical information Sr was assumed to promote osteoclast apoptosis and inhibit osteoblast apoptosis.

By combining these in silico models (Supplementary Methods S1.1 to S1.4) with a voxel finite element method (FEM) for mechanical analysis (see Materials and Methods) (18, 27), we have constructed a unique and state-of-the-art in silico experimental platform (V-Bone) that incorporates mechano-biochemical coupling into bone remodeling.

Cancellous bone alters its trabecular orientation to coincide with principal stress trajectories, a phenomenon known as Wolffs law (2830). V-Bone enables observation of such mechanical adaptation in silico. To qualitatively verify the validity of the in silico model from a mechanical viewpoint, we reproduced bone adaptation to mechanical loading in a single trabecula and in cancellous bone spanning multiple trabeculae.

First, we simulated the adaptation of single trabeculae with two different configurations to compressive loading. A cylindrical trabecula with an inclined longitudinal axis was found to reorient parallel to the loading direction (Fig. 2A). In a Y-shaped trabecula, the branches moved toward each other. These results show functional adaptations in a single trabecula in response to external loads.

(A) Morphological changes by cooperative osteoclastic bone resorption (red) and osteoblastic bone formation (blue) in an inclined single trabecula (left) and a Y-shaped trabecula (right) under compressive load. Both trabeculae were compressed through elastic plates to attain 0.1% apparent strain along the z direction. (B) Three-dimensional model of a mouse distal femur reconstructed from microcomputed tomography images. This model was compressed to attain 0.1% apparent strain along the z direction, corresponding to the longitudinal direction of the femur. A cancellous bone cube with edge size 735 m was selected as volumetric region of interest. (C) Morphological changes in trabeculae in the region of interest after 10 weeks of remodeling. A trabecula acquired the morphology suitable for supporting the load (red arrowhead), while a trabecula perpendicular to the loading direction was eroded (yellow arrowhead). (D) Measurement of the structural anisotropy of trabeculae in the region of interest using fabric ellipsoids based on the mean intercept length method. The lengths of the three principal semi-axes are denoted Hi, i = 1, 2, 3 (H1 > H2 > H3). The degree of anisotropy, defined as H1/H3, increased from 1.28 to 1.43 after remodeling. For clarity, the fabric ellipsoid is displayed at twice its true size.

We then simulated the morphology of cancellous bone in a mouse distal femur subjected to physiological compressive loading using a model reconstructed from microcomputed tomography images (hereinafter called control model; Fig. 2B). Comprising multiple trabeculae within the inner cuboid region, most trabeculae acquired morphology suitable for supporting the load within 10 weeks (red arrowheads in Fig. 2C and movie S1). Several trabeculae perpendicular to the loading direction were also lost by bone resorption (yellow arrowheads in Fig. 2C). These results show that although individual trabeculae are networked in cancellous bone, they successfully adapt to imposed mechanical loads.

To quantify the adaptation in the region of interest, structural anisotropy was evaluated based on a fabric ellipsoid obtained by the mean intercept length method (18, 27). The direction of the three principal axes of the ellipsoid coincides with the principal directions of trabecular orientation, and their lengths indicate the characteristic lengths spanning bone and marrow space in the corresponding directions. Strikingly, the fabric ellipsoid stretched along the z direction as a result of 10-week remodeling (Fig. 2D), implying that cancellous bone acquired trabecular architecture totally parallel to the loading direction to satisfy the mechanical demand and suggesting functional adaptation at multiple trabeculae.

Together, the results indicate that by modeling complex intercellular signaling, V-Bone can reproduce bone adaptation to the mechanical loading, not only in a single trabecula but also in cancellous bone.

Osteoporosis, which is characterized by low bone mineral density and low bone quality, substantially reduces bone strength, leading to increased risk of bone fractures. The disease is triggered by low mechanical stress due to disuse (31) or by accumulation of factors that promote bone resorption, e.g., RANKL, due to sex hormone imbalance (57). On the other hand, osteopetrosis is one of inhered osteosclerotic disorders in which osteoclast dysregulation results in excess bone formation and bone hardening. Previously, we reported that conditional knockout of RANKL triggers osteopetrosis in mice (23). For qualitative verification of the in silico model from a biochemical viewpoint, we reproduced these metabolic bone diseases that include unloading-induced osteoporosis, as well as osteoporosis and osteopetrosis due to abnormal RANKL expression, by using multiple mouse femurs (N = 5).

We reproduced osteoporosis due to low mechanical stress, as observed in cases of extended bed rest and space flight (31). In particular, mouse femurs were simulated under low compressive loadings (hereinafter called unloading model) and compared with the control models (movies S2 to S5). In the unloading model, several trabeculae were lost around the central region of the femur (Fig. 3A), owing to excess bone resorption by osteoclasts at trabecular surfaces (Fig. 3B). Accordingly, the bone volume/tissue volume (BV/TV) ratio remarkably decreased in the first 2 weeks compared to that in the control model because of an increase in the osteoclast surface/bone surface (Oc.S/BS) ratio and a decrease in the osteoblast surface/bone surface (Ob.S/BS) ratio. Nevertheless, BV/TV plateaued after 2 weeks (Fig. 3C), indicating that cancellous bone adapts to the loss of external load within 2 weeks, at which point bone resorption and formation are again at equilibrium.

(A) Change in cancellous bone morphology after 5 weeks in a control model and an unloading model (in proximal view). In the unloading model, the applied uniaxial strain was 1/10 of that applied to the control model. Scale bar, 1 mm. (B) Enlarged views of cancellous bone in control and unloading models. Osteoclasts and osteoblasts on the trabecular surface are colored red and blue, respectively. Voxel size, 15 m. (C) Quantification of changes in BV/TV, Oc.S/BS, and Ob.S/BS for 10 weeks in control (N = 5) and unloading models (N = 5). Oc.S/BS and Ob.S/BS are normalized by total bone surface. (D) Change in cancellous bone morphology for 10 weeks in an osteoporosis and osteopetrosis model (in proximal view). In these models, production of RANKL from the bone surface, exclusive of surface osteoclasts, was set to 1.3 and 0.7 times of that in the control model, respectively. Scale bar, 1 mm. (E) Quantification of changes in BV/TV, Oc.S/BS, and Ob.S/BS over 10 weeks in control (N = 5), osteoporosis (N = 5), and osteopetrosis models (N = 5).

We also reproduced osteoporosis by up-regulating RANKL (hereinafter called osteoporosis model) (movies S6 and S7). In contrast to the unloading model, the osteoporosis model formed trabeculae throughout the femur (Fig. 3D, top). In addition, sustained activation of osteoclasts and slight inhibition of osteoblasts resulted in a gradual decrease in BV/TV over 10 weeks (Fig. 3E). These results imply that osteoporosis due to RANKL overexpression is characterized by chronic bone loss, while osteoporosis due to low mechanical stress is characterized by acute bone erosion (Fig. 3C). These observations are consistent with experimental data showing that BV/TV during bed rest or space flight decreases about 10 times faster than in primary osteoporosis (31).

Last, we reproduced an osteopetrotic state, which is characterized by abnormally high bone density, by down-regulating RANKL (hereinafter called osteopetrosis model) (movies S8 and S9). This model is characterized by increased trabecular thickness (Fig. 3D, bottom), with BV/TV monotonically increasing with time due to loss of RANKL-induced osteoclastogenesis (Fig. 3E).

Collectively, we have successfully simulated osteoporotic and osteopetrotic pathologies in silico, suggesting that V-Bone may reproduce a variety of metabolic bone diseases due to mechanical and biochemical determinants such as loss of mechanical stress and abnormal expression of signaling molecules.

Here, we describe an innovative approach to investigate the role of an essential signaling molecule in bone remodeling, in which the molecule of interest is perturbed in silico as is often done in vivo. Previously, mice deficient in Sema3A, a dual-function signaling molecule that inhibits bone resorption and promotes bone formation, were found to have a severe osteopenic phenotype due to osteoclast accumulation (24). Conversely, bone volume increases in mice treated with Sema3A, following loss of osteoclasts and accumulation of osteoblasts. We conducted in silico perturbation of Sema3A using multiple mouse femurs (N = 5) under the same conditions as in these in vivo experiments. Through quantitative comparison of the in vivo and in silico experimental results, the in silico model was validated.

Sema3A-deficient mice were modeled by down-regulating Sema3A (hereinafter called Sema3A-deficient model) and compared to the control model. Cancellous bone morphology in the Sema3A-deficient model was similar after 10 weeks of simulation to that obtained in vivo (Fig. 4A), with BV/TV and trabecular number (Tb.N) significantly smaller than those in the control model (Fig. 4B). In addition, the Sema3A-deficient model initially accumulated more osteoclasts at the trabecular surface to enhance bone resorption (Fig. 4, C and D). These results quantitatively resemble in vivo data (24).

(A) Cancellous bone morphology in a mouse femur obtained by in vivo and in silico experiments on Sema3A-deficient mice. In the Sema3A-deficient model, production of Sema3A from the bone surface, exclusive of surface osteoclasts, was set to 0.5 times of that in the control model. Scale bar, 1 mm. (B) BV/TV and Tb.N as measured in vivo and in silico (N = 5). (C) Distribution of osteoclasts and osteoblasts on the trabecular surface immediately after starting simulation of control and Sema3A-deficient models. Voxel size, 15 m. (D) Oc.S/BS and Ob.S/BS as measured in silico (N = 5). (E) Cancellous bone morphology in vivo and in silico in control and Sema3A-treated mice. Treatment with Sema3A was simulated by setting Sema3A production from the bone surface, exclusive of surface osteoclasts, to 1.5 times of that in the control model. Scale bar, 1 mm. (F) BV/TV and Tb.N as measured in vivo and in silico (N = 5). (G) Distribution of osteoclasts and osteoblasts on the trabecular surface after 5 weeks without treatment and immediately after starting Sema3A treatment. Voxel size, 15 m. (H) Oc.S/BS and Ob.S/BS as measured in silico (N = 5). **P < 0.01; ***P < 0.005; NS, not significant, by Students t test.

To investigate the therapeutic potential of Sema3A, bone remodeling was simulated for 5 weeks in the control model, followed by up-regulation of Sema3A for 5 weeks (hereinafter called Sema3A-treated model). The Sema3A-treated model generated thicker trabeculae than the control model after 10 weeks, as observed in vivo (Fig. 4E). The corresponding BV/TV and Tb.N values were also in close agreement with in vivo data (Fig. 4F). Immediately after Sema3A treatment, osteoblasts accumulated at the trabecular surface, as observed in vivo (Fig. 4, G and H).

Together, the data showed that in silico perturbation is a powerful way to clarify the effects of signaling molecules on bone dynamics at molecular/cellular and tissue/organ scales. Hence, such experiments may enhance the design of subsequent in vivo experiments and thus provide a novel approach to inspire and test new hypotheses regarding complex biological phenomena.

We propose a method to predict the therapeutic effects of various drugs against metabolic bone diseases in silico using V-Bone. We have now used this method to investigate the effects of dose, the resulting bone quality after drug treatment, and even the effects of different treatment regimens. In particular, we simulated the treatment of osteoporosis using bisphosphonate, anti-RANKL, anti-sclerostin, and Sema3A. Bisphosphonate, a current first-line therapy against osteoporosis, is specifically taken up by osteoclasts and is an inhibitor of bone resorption (11). Similarly, anti-RANKL potently inhibits bone resorption by suppressing osteoclastogenesis via RANKL (11, 12). Anti-sclerostin blocks binding of sclerostin to LRP5/6 and activates canonical Wnt signaling, thereby promoting bone formation and suppressing bone resorption (11, 22). Sema3A inhibits osteoclastic bone resorption and promotes osteoblastic bone formation (24). The effects of these drugs were modeled in V-Bone (see Supplementary Methods S1.5).

To predict the effects of patient-specific drug treatment, we simulated standard- and high-dose treatments (Fig. 5A) of one specific mouse femur, which are absolutely impossible to conduct in vivo. We assumed an idealized administration of each drug where the bioavailability is 100% and the plasma drug concentration is constant. In untreated osteoporotic models, BV/TV decreased from 18 to 9% after 10 weeks (Fig. 5B). At standard doses of all four drugs, BV/TV stabilized at about 15%. Standard doses also suppressed osteoclastogenesis (Fig. 5C). Whereas anti-sclerostin and Sema3A up-regulated osteoblastogenesis, bisphosphonate and anti-RANKL did not (Fig. 5D). These simulation results are consistent with the therapeutic effects reported in the in vivo experiments (32, 33). At high doses (threefold of the standard dose), antibodies to RANKL and sclerostin suppressed osteoclastogenesis (Fig. 5C), while anti-sclerostin and Sema3A enhanced osteoblastogenesis (Fig. 5D). Consequently, high doses of anti-sclerostin were the most effective in increasing BV/TV, while high doses of bisphosphonate exerted little influence on bone volume (Fig. 5B). Thus, therapeutic benefits gained from dose escalation substantially depend on the mechanism of action of the drug, highlighting the value of computational drug assessment in dose management.

(A) Cancellous bone morphology in a mouse femur modeled in silico without and with drug treatment. Upper panels show osteoporotic bones treated without and with drugs at high doses for 10 weeks. Lower panels are enlarged views. (B to D) Changes in (B) BV/TV, (C) Oc.S/BS, and (D) Ob.S/BS during drug treatment. (E) Rm.S/BS immediately after starting treatment with standard doses, and fraction of Oc.S/BS and Ob.S/BS in Rm.S/BS. (F) Apparent stiffness of cancellous bone along the loading direction after 10 weeks of drug treatment at standard dose. (G) Percentage changes in BV/TV and Oc.S/BS from the initial state when continuing or discontinuing anti-RANKL therapy. (H) Percentage changes in Ob.S/BS from the initial state when continuing bisphosphonate therapy or transitioning to anti-RANKL and anti-sclerostin therapy.

In silico medication experiments enable analysis not only of bone quantity but also of bone quality, an important index for drug assessment. Although all four drugs stabilized BV/TV at almost the same level, the resulting bone quality varied, especially as assessed by repair of accumulated microdamage through remodeling (i.e., bone turnover rate) and by mechanical function to support external loads (i.e., bone mechanical integrity). Bone turnover rate was estimated as remodeling surface/bone surface (Rm.S/BS), also defined as the sum of Oc.S/BS and Ob.S/BS. Bone mechanical integrity was evaluated as the apparent stiffness of cancellous bone along the loading direction, a property that strongly depends on trabecular architecture (34, 35). Simulation results showed that administration of anti-sclerostin and Sema3A generates relatively high Rm.S/BS (Fig. 5E, left), mainly because of enhanced generation of osteoblasts (Fig. 5E, right). On the other hand, the apparent stiffness of cancellous bone after bisphosphonate therapy was lower than that after treatment with all other drugs (Fig. 5F). These results suggest that drugs that promote bone formation but inhibit bone resorption are more effective in improving both bone quantity and quality. The data also highlight that in silico experiments, unlike in vivo experiments, can simultaneously analyze cellular activities and mechanical properties for drug assessment.

Furthermore, in silico medication experiments provide a powerful way to predict the therapeutic effects of potential treatment regimens. For example, we simulated the following clinically relevant scenarios: discontinuation of anti-RANKL (36) and transition from bisphosphonate to anti-RANKL or anti-sclerostin (37). These scenarios were simulated to occur 5 weeks after treatment with the standard dose. Discontinuation of anti-RANKL decreased BV/TV at a constant rate (Fig. 5G, left) but rapidly increased Oc.S/BS, although the latter also gradually declined after peaking (Fig. 5G, right). These behaviors qualitatively coincide with clinical effects observed after discontinuation of anti-RANKL (36). Switching from bisphosphonate to anti-sclerostin increased Ob.S/BS to a larger extent than switching to anti-RANKL or retaining bisphosphonate (Fig. 5H). Together, the data suggest that V-Bone may potentially assist clinicians to devise previously untested treatment regimens before clinical trials.

We have developed a novel in silico experimental platform (V-Bone) to investigate spatial and temporal behavior of bone remodeling regulated by mechano-biochemical couplings, while previous in silico models of bone remodeling addressed bone structure/function and bone cell dynamics separately. The platform enables spatiotemporal observation and prediction of bone physiological and pathological conditions resulting from complex intercellular signaling. In conjunction with in vivo and in vitro experiments, in silico experiments provide a third avenue to explore bone metabolism and may thus accelerate research. Furthermore, we anticipate that V-Bone will prove valuable in clinical practice, such as in comprehensive drug assessment and formulation of effective treatment regimens.

The in silico model of bone remodeling was qualitatively verified from mechanical and biochemical viewpoints: We reproduced bone adaptation to mechanical loading (Fig. 2), as well as pathological bone states due to low mechanical stress and abnormal expression of signaling molecules (Fig. 3). To more rigorously validate the in silico model, we also demonstrated in silico perturbation of a specific signaling molecule, a standard in vivo technique in life science, and quantitatively compared the results with those from corresponding in vivo experiments (Fig. 4). In silico perturbation enables observation of the spatial and temporal dynamics of bone remodeling, which is difficult to achieve in vivo. Last, we applied the in silico model to predict the therapeutic effects of various drugs against osteoporosis and showed that in silico medication experiments provide a powerful way to assess the effects of drugs on bone cells and morphology in clinically relevant scenarios (Fig. 5). In all the in silico experiments conducted in the present study, mouse femurs were uniaxially compressed despite multiple loadings in vivo because of a lack of information on actual boundary conditions, which resulted in a unidirectional trabecular structure (Fig. 2, C and D). By considering more realistic loading conditions in the in silico model, which can produce various trabecular orientations (28), the reproducibility of the trabecular structure in response to mechanical loadings will be quantitatively corroborated by in vivo experimental data.

Measuring bone turnover markers and bone mineral density is the conventional noninvasive method to evaluate bone metabolic dynamics. Whereas this technique can measure temporal changes in the balance between bone resorption and formation, the resulting data do not include spatial information on bone morphology and cellular distribution. Although x-ray microcomputed tomography (38) can help bridge bone metabolism to the three-dimensional bone microstructure, live imaging of cellular behavior is difficult. Recently, intravital imaging of bone tissue has gained much attention as a new technique for real-time observation of spatiotemporal cellular activities (39), although it is only suitable for flat bone such as calvaria. In comparison to these experimental methods, V-Bone allows simultaneous spatiotemporal in silico observation and prediction of the distribution of signaling molecules, of bone cellular behaviors, and of bone microstructure.

An in silico experiment is an innovative way to explore molecular phenomena and thus will contribute invaluably to the progress of life science. The standard method to elucidate the role of a specific signaling molecule in a complex biological system is to test a research hypothesis in vivo, typically by perturbing the molecule of interest by techniques such as genetic manipulation. In contrast, we perturbed Sema3A in silico, a molecule that exhibits dual functions of inhibiting bone resorption and promoting bone formation, to emphasize the value of this approach. Bone morphometric data obtained in silico were quantitatively in good agreement with those obtained by corresponding in vivo experiments. These findings suggest that in silico perturbation may generate new research hypotheses that can then be tested in vivo, thereby accelerating hypothesis-test cycles to resolve outstanding research questions.

In silico medication experiments to predict the therapeutic efficacy of drugs against metabolic bone diseases are one of the promising clinical applications of V-Bone. Comprehensive in silico drug assessment at the preclinical phase of development will likely help clinicians determine the optimal strategy for drug administration and thus dramatically reduce the time and expense needed for large-scale clinical trials. In addition, in silico medication experiments will enable time-lapse evaluation of bone quality and bone quantity, especially because V-Bone uniquely predicts both cellular dynamics and tissue mechanical state in an individual patient. In the present in silico medication experiments, to focus on the relationship between mechanism of action of drugs and their therapeutic effects, we did not take into account the differences in bioavailability and biological half-life among the drugs. For clinical usage of V-Bone in the future, it is indispensable to incorporate these critical factors for pharmacokinetics that affect therapeutic efficacy. Thus, V-Bone may potentially enable personalized treatments for improving bone quantity and quality.

The concept of in silico experiments is greatly different from that of conventional computer simulations. In conventional computer simulations to capture the nature of complex phenomena through their replication, it has been considered that the number of parameters included in the in silico model should be kept as low as possible, and sensitivity analysis of these parameters can help us understand the essential characteristics of the phenomenon of interest. On the other hand, in silico experiments aim at observing the complex phenomena in silico as they occur in vivo to analyze the underlying mechanism and predict the events caused by arbitrary perturbation. Therefore, a model for in silico experiments is required to be constructed by taking into account the complexity inherent in the phenomena; hence, a large number of parameters are included in the in silico model (see tables S1.1 to S1.3). Some parameters that are difficult to determine directly from in vivo or in vitro experiments have to be set by heuristic methods. In addition, sensitivity analysis of all parameters included in an in silico model is almost impossible because of the huge degree of freedom. However, in the case of in silico experiments, parameter sensitivity analysis has the same meaning as in silico perturbation to investigate the effects of corresponding factors, which is a notable difference from conventional computer simulations. Once the proposed in silico model is validated through quantitative comparison with in vivo or in vitro experimental results, in silico perturbation of specific parameters in the in silico model, which is conventionally regarded as a parameter sensitivity analysis, holds promise for revealing an overlooked importance of unexpected factors.

Bone metabolism in our living bodies is regulated by many kinds of cells, such as hematopoietic stem cells and mesenchymal stem cells in the bone marrow, and related various signaling molecules. Furthermore, bone metabolism is coupled to a large biological system that includes endocrine, immune (40), and nervous systems (41). To highlight osteocyte-driven bone remodeling regulated by local signaling factors, in the present study, we explicitly modeled only osteoclasts, osteoblasts, and osteocytes, which are directly responsible for the change in bone volume, and several signaling molecules primarily relating to different functions. Despite these limitations, V-Bone was quantitatively validated through in silico perturbation of Sema3A (Fig. 4). This suggests that essential aspects of the actual complex molecular and cellular mechanism of bone remodeling can, to some extent, be represented by a reduced in silico model. Further expansion of V-Bone by incorporating other molecules or cells of interest will increase its prediction accuracy and expand the range of application. Thus, V-Bone is a promising framework, which potentially develops by including additional molecular and cellular mechanisms, to investigate the complexity inherent in bone remodeling and fully understand bone metabolism. We expect that experimental data about underlying molecular, cellular, and systems behaviors will accumulate exponentially in the near future. Accordingly, in silico experiments that integrate large data sets from in vivo and in vitro experiments will become more important as an alternative approach to investigate a wide range of molecular and cellular interactions. Incorporating quantitative in vivo and in vitro experimental data in the in silico models will enhance the validity of in silico experiments. We anticipate that V-Bone will accelerate bone metabolism and remodeling studies through comprehensive understanding of molecular, cellular, tissue, and organ dynamics.

Mechanical stress in bone tissue was analyzed by a voxel FEM (18, 27). Briefly, finite element models of mouse distal femurs (N = 5) were constructed from microcomputed tomography images. Each model was discretized using eight-node cubic finite elements with edge size 15 m. The bone was assumed to be homogeneous and isotropic, with Youngs modulus E = 20 GPa and Poissons ratio = 0.3. By using von Mises equivalent stress eq obtained through finite element analysis, the mechanical information Sr that regulates bone remodeling was determined (see Supplementary Methods S1.1).

The mechanical information Sr was coupled with intercellular signaling by influencing the production rate of sclerostin PSCL (eqs. S10 and S11, see Supplementary Methods S1.2 and S1.3). The reaction-diffusion equations (Fig. 1C and eq. S8) governing the spatial and temporal behavior of signaling molecules within the bone marrow were solved by an explicit finite difference method, in which the marrow space was discretized using the same voxel mesh as the FEM model. The effects of the drugs for osteoporosis were incorporated into the same equations (see Supplementary Methods S1.5).

The concentration of the specific signaling molecules and the mechanical information Sr determine the probabilities of cell genesis (i.e., differentiation from precursor cells and proliferation) pgeni and apoptosis papoi for osteoclasts and osteoblasts (i = ocl or obl) (Fig. 1D, eqs. S24 to S27, see Supplementary Methods S1.4). According to these probabilities, osteoclasts and osteoblasts are recruited on the bone surfaces or removed from them. The recruited osteoclasts and osteoblasts can alter the bone surface by resorbing old bone or forming new bone, respectively. To represent the changes in cancellous bone morphology, the level set method was used (42), because this method is capable of tracking the movement of individual trabecular surfaces (see Supplementary Methods S1.6). Cortical bone located near the outer surface of femurs was assumed to be not subject to morphological changes via remodeling.

Parameters used in in silico experiments are listed in tables S1 to S3. All the in silico experiments were carried out using an in-house code written in Fortran 90. The results were visualized with the open-source software ParaView (Kitware Inc.).

Acknowledgments: We thank Y. K. Kim, Y. Inoue, and K. O. Okeyo for discussions and comments. We also thank R. Terazawa for editing the figures and tables. Funding: This work was supported by Advanced Research and Development Programs for Medical Innovation (AMED-CREST), Elucidation of Mechanobiological Mechanisms and their Application to the Development of Innovative Medical Instruments and Technologies from Japan Agency for Medical Research and Development (AMED) (JP19gm0810003), the Acceleration Program for Intractable Diseases Research Utilizing Disease-Specific iPS cells from AMED (JP19bm0804006), Cross-Ministerial Strategic Innovation Promotion Program (SIP) (3D Design & Additive Manufacturing) from Japan Science and Technology Agency (JST), and VCAD System Research Program, RIKEN. Author contributions: Y.K. and T.A. designed the project and wrote the manuscript. Y.M. performed in silico experiments. M.H. and T.N. provided in vivo experimental data and collaborated with Y.K. and T.A. to plan the study and interpret the data. Competing interests: The authors declare that they have no competing interests. Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. Additional data and source codes related to this paper may be requested from the authors.

See the article here:
In silico experiments of bone remodeling explore metabolic diseases and their drug treatment - Science Advances

Cell Biology

Zebrafish are the tropical minnows advancing genetics and molecular biology – TMC News – Texas Medical Center News

Iridescent blue-striped zebrafish dart back and forth in tiny tanks stacked floor-to-ceiling in the basement of the Baylor College of Medicine. The freshwater minnowssome 13,000 strong in their watery studio apartmentsplay an integral role in innovative biomedical research.

They are part of the Gorelick Lab, one of more than 3,250 sites in 100 different countries using zebrafish to advance medicine and better understand human diseases. Led by Daniel Gorelick, Ph.D., assistant professor in the department of cellular and molecular biology at Baylor, the lab studies zebrafish to learn how certain hormones and chemicals affect the development and function of the human heart and brain, as well as other tissues.

Although science and technology are constantly evolving, zebrafish have remained relevant research tools for almost 50 years. Today, scientists are harnessing the power of CRISPR-Cas9 technologywhich can edit segments of the genome by deleting, inserting or altering sections of the DNAto generate specific mutations in zebrafish.

This has been a huge advance because it allows us to create mutant strains of zebrafish that have the same mutations as are found in a human disease, said Gorelick, whose lab is housed in Baylors Center for Precision Environmental Health and is currently undergoing an expansion to accommodate as many as 30,000 fish.

In addition, scientists have long sought to map the cell-by-cell progression of animals, in pursuit of understanding how a single cell develops into trillions of cells that make up an intricate biological system of organs. With single-cell RNA sequencing, a technology named Science magazines 2018 Breakthrough of the Year, scientists are able to track the different, intricate stages of embryo development in unprecedented detail, allowing researchers like Gorelick to study the cascading effects at the cellular level.

Theres just so much evidence now that a lot of the drugs that are effective in humans are also effective in [zebrafish], so people are now starting to use fish to discover drugs, Gorelick said. You want to know, if youre taking a drug or youre exposed to some pollutant, does that cause birth defects? How does that affect the life of humans? We can use [zebrafish] as research tools to understand how the chemicals normally work in a normal embryo.

Regenerative heartZebrafish are named for the colorful horizontal stripes on their bodies, and can grow from 1.5 to 2 inches in length. The tropical fish are native to South Asia.

On the surface, zebrafish appear nothing like humans, but 70 percent of the genes in humans are found in zebrafish and 84 percent of human genes associated with human disease have a zebrafish counterpart, studies show.

George Streisinger, an American molecular biologist and aquarium enthusiast, pioneered the use of zebrafish in biomedicine at the University of Oregon in 1972. His breadth of knowledge about zebrafish laid the groundwork for research methodologies, including developing breeding and care standards and creating tools for genetic engineering and analysis. He performed one of the first genetic screens of zebrafish by using gamma rays to randomly mutate the DNA of certain zebrafish and identify offspring that had notable phenotypes, such as pigmentation defects.

That caused a big explosion in the field and then thats when things really took off, Gorelick said.

Zebrafish are now used as a genetic model for the development of human diseases, including cancer, cardiovascular diseases, infectious diseases and neurodegenerative diseasesto name a few. Housed down the street from Gorelicks lab, John Cooke, M.D., Ph.D., is using zebrafish to study atherosclerosis, the major cause of heart disease in the country. Although zebrafish have only one ventricle to pump blood to the heart, whereas humans have two (a left and a right ventricle), their vasculature is very similar to humans.

The zebrafish can help us in understanding the cardiovascular system, in achieving those basic insights, and in translating those basic insights towards something thats potentially useful for people, said Cooke, director of the Center for Cardiovascular Regeneration at Houston Methodist Research Institute.

Cooke hopes that studying the regenerative capabilities of the zebrafish heart will lead to new discoveries that help human patients.

You can remove 20 percent of their heart, and they can regenerate it, Cooke explained. Why is that? We want to know. There are groups that are studying that amazing regenerative capacity of the [zebrafish] heart, and those insights obtained from that work may lead us to new therapies for people to regenerate the human heart or, at least, improve the healing after a heart attack.

Watching cells migrateAlthough mice are genetically closer to humans than zebrafish, sharing 85 percent of the same genomes, zebrafish have a few key advantages for researchers.

On average, zebrafish produce between 50 to 300 eggs, all at once, every 10 days. Their rapid breeding allows scientists to quickly test the effects of genetic modifications (such as gene knockouts and gene knock-ins) on current fish, as well as ensuing generations.

In addition, zebrafish are fertilized and developed externally, meaning the sperm meets the egg in the water. This allows scientists to access the embryos more easily, as opposed to mouse embryos that develop inside the womb. In one of his research projects, Gorelick simply adds drugs to the water to see how the zebrafish are affected.

Most drugs in the water will get taken up by the embryo, Gorelick said. We add it into the water and it gets taken up the next day when theyre just one day old. All of that discovery happened in zebrafish because you can literally watch it live.

Not only do zebrafish embryos develop quickly, they are also transparent. Within two to four days, a zebrafish will develop all its major organsincluding eyes, heart, liver, stomach, skin and fins.

We can literally watch these cells migrate from different parts of the embryo, form the tube, constrict, form the hourglass, loop on itself, beat regularly and see blood flow all at the same time, Gorelick said. When theres a belly and a uterus, you dont have access. You can use things like ultrasound, like we do with humans, but you cant get down to single-cell resolution like we can with the fish.

Ultimately, zebrafish have proven to be a powerful resource for researchers. Although all zebrafish studies are confirmed in rats and mice, followed by human tissue, they constitute a significant stepping stone.

You wouldnt want to build a house only using a hammer and a screwdriver. I want a power drill and I want a band saw, Gorelick said. Fish are part of that. Theyre not a cure-all. Theyre not the only tool, but theyre an important tool.

Read this article:
Zebrafish are the tropical minnows advancing genetics and molecular biology - TMC News - Texas Medical Center News

Cell Biology

Breast Cancer and Resistance to Hormone Therapy – OncoZine

A team of researchers led by scientists at Baylor College of Medicine has new insights into the function of neurofibromin, a tumor suppressor produced by the NF1 gene.

Neurofibromin keeps cancer growth in check by repressing the activity of a cancer driver called Ras, which is part of a family of related proteins belonging to a class of protein called small GTPase. Ras is involved in transmitting signals within cells, known as cellular signal transduction. Ras is the prototypical member of the Ras superfamily of proteins, which regulate diverse cell behaviors.

Previously unknown functionThe team of researchers discovered a previously unknown function of neurofibromin directly repressing gene expression controlled by the estrogen receptor- (ER). Thus, when neurofibromin is lost, Ras and ER functions are both activated, causing treatment resistance and metastasis for ER+ breast cancer.

The findings, published in Cancer Cell, suggest that a therapeutic approach must combine two different drugs, a SERD (e.g., fulvestrant) to degrade ER and a MEK inhibitor (e.g., selumetinib or binimetinib) to inhibit Ras downstream signaling, in order to effectively treat neurofibromin-depleted ER+ breast cancer. When this combination therapy was tested in animal models, the result was tumor regression. The next step is to begin clinical trials of the effectiveness of this therapeutic approach in patients.[1]

Driving tamoxifen and aromatase inhibitor resistanceThis researchers first studied the importance of neurofibromin loss in a study they published in 2018 in which tumor DNA was sequenced to seek mutations that can promote resistance to tamoxifen, which is commonly used to prevent relapses from ER+ breast cancer.[2]

When we examined the mutational patterns in NF1, we observed that poor patient outcomes only occurred when neurofibromin was lost, not through mutations that selectively affect Ras regulation. This suggested to us that neurofibromin may have more than one function, explained Eric C. Chang, Ph.D. one of two senior authors on the paper, an associate professor in the Department of Molecular and Cellular Biology and a member in the Dan L Duncan Comprehensive Cancer Centers Lester and Sue Smith Breast Center.

This thought triggered studies, spearheaded by Zeyi Zheng a lab member in Changs laboratory, into the function of neurofibromin in ER+ breast cancer cells.

One of his early experiments showed that when the expression of NF1 is inhibited, a process designed to mimic neurofibromin loss in tumors, the resulting ER+ breast cancer cells were instead stimulated by tamoxifen and, not as usual, inhibited.

The researchers also noted that these neurofibromin-depleted cells became sensitive to a very low concentration of estradiol, a form of estrogen.

The clinical relevance of these findings was immediately apparent because it suggested that tamoxifen or aromatase inhibitors, which lower estrogen levels available to the cancer cells, would be the wrong choice for treatment when neurofibromin is lost by the tumor, said co-senior author Matthew J. Ellis, MB, BChir, BSc., Ph.D., FRCP, professor and director of the Lester and Sue Smith Breast Center and a McNair Scholar at Baylor.

Linking neurofibromin to ERFollow-up gene expression studies all strongly suggest that neurofibromin behaves like a classic ER co-repressor.

A co-repressor must bind ER directly, but the group hesitated to conduct such an experiment without more evidence because it is not trivial to do so, Chang noted.

A breakthrough came when Charles E. Foulds, Ph.D., a primary faculty member and associate professor at the Center for Precision Environmental Health/Molecular & Cellular Biology and Associate Member of the Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine Houston, Texas, United States, a co-author on the paper, searched the Epicome, a massive proteomic database created by Anna Malovannaya, Ph.D. and Jun Qin, Ph.D. at Baylor, as part of an effort by Bert OMalley, MD, a chancellor, and professor of molecular and cellular biology at Baylor, to comprehensively document all the proteins associated with ER.

Foulds found neurofibromin in the database, which encouraged the team to ultimately demonstrate that ER and neurofibromin interact directly. However, to seriously consider NF1 as an ER co-repressor, there was still another missing piece of the puzzle.

One day Charles casually asked me whether neurofibromin has a region rich in the amino acids leucine and isoleucine, because co-repressors use these motifs to bind ER, and it dawned on me that neurofibromin indeed does, Chang said.

In fact, neurofibromin has two such motifs that mediate ER binding in a cooperative manner. These motifs are frequently mutated in cancers but are not required for Ras regulation, he added.

Treating neurofibromin-deficient ER+ breast cancerSince tamoxifen or aromatase inhibitors were found to be ineffective for neurofibromin-deficient ER+ breast cancer tumors, preclinical models were used to show that the ER-degrading drug fulvestrant was still effective. However, fulvestrant only temporarily inhibited tumor growth because secondary Ras-dependent fulvestrant resistance was induced by neurofibromin-loss. This Ras-dependent growth phase could be inhibited with the addition of a MEK inhibitor, which shuts off a key signaling pathway downstream of Ras.

The researchers validated this combination treatment strategy using a patient-derived xenograft (PDX) mouse model which can maintain the genomics and drug response of the original human tumor from which it was derived. [3]

In this case, this PDX was derived from a patient who failed several lines of endocrine therapy and already developed fulvestrant resistance.

The results of the combination therapy were encouraging the tumor shrunk to almost undetectable levels, Chang said. Our next goal is to test this combination therapy in clinical trials in order to determine its therapeutic potential in the clinic.

Neurofibromin loss is present in at least 10% of metastatic ER+ tumors. As a result of these new data, we are now working on a clinical trial that combines a MEK inhibitor, with fulvestrant, said Ellis, Susan G. Komen Scholar and associate director of Precision Medicine at the Dan L Duncan Comprehensive Cancer Center at Baylor.

Interestingly, MEK inhibitors are also being used to control peripheral nerve tumors in patients with neurofibromatosis, where a damaged NF1 gene is inherited. Our findings contribute to an understanding of why female neurofibromatosis patients also have a much higher incidence of breast cancer.

Reference[1] Zheng ZY, Anurag M, Lei JT, Foulds CE, Ellis MJ, Chang EC, et al. Neurofibromin Is an Estrogen Receptor- Transcriptional Co-repressor in Breast Cance. Cancer cell. March 05, 2020 DOI:https://doi.org/10.1016/j.ccell.2020.02.003 [Article][2] Griffith OL, Spies NC, Anurag M, Griffith M, Luo J, Tu D, Yeo B, Kunisaki J, Miller CA, et al. The prognostic effects of somatic mutations in ER-positive breast cancer. Nat Commun. 2018 Sep 4;9(1):3476. doi: 10.1038/s41467-018-05914-x. Erratum in: Nat Commun. 2018 Nov 14;9(1):4850. PMID: 30181556; PMCID: PMC6123466. [Article][3] Li S, Shen D, Shao J, Crowder R, Liu W, Prat A, He X, Liu S, Hoog J, et al. Endocrine-therapy-resistant ESR1 variants revealed by genomic characterization of breast-cancer-derived xenografts. Cell Rep. 2013 Sep 26;4(6):1116-30. doi: 10.1016/j.celrep.2013.08.022. Epub 2013 Sep 19. PMID: 24055055; PMCID: PMC3881975. [Article]

Read more:
Breast Cancer and Resistance to Hormone Therapy - OncoZine

Cell Biology

The man behind Margot Robbie and Victoria Beckham’s favourite skin cream – The Times

Victoria Beckham thinks its AMAZING and Vanity Fair described it as a real-life time machine meet the wrinkle cream for which the A-list are prepared to pay 8 a squirt. Net-A-Porter can barely keep it in stock and the product itself has racked up sales of more than 4.7 million in only two years.

Margot Robbie uses Augustinus Bader, as does Carla Bruni. Rosie Huntington-Whiteley, Naomi Campbell and Yasmin le Bon are all fans. Beckham was so obsessed, she enlisted its creator to come up with a moisturiser for her own range.

I meet Professor Bader, director of applied stem cell biology and cell technology at the University of Leipzig, at the 0.01 per cent Bulgari Hotel in Knightsbridge, London, a few days after

Read more from the original source:
The man behind Margot Robbie and Victoria Beckham's favourite skin cream - The Times

Cell Biology

Scorpion Venom Used to Direct T Cells to Target Brain Cancer Tumors – SciTechDaily

Blue indicates the cell nuclei (big: tumor cell; small: T cell). The aggregation of yellow color at the interface between the two cells is the formation of immune synapse, a key indicator of T cell activation which will lead to tumor killing. Credit: City of Hope

The research published today, and scorpion venom will also be key component of CAR T cell therapy for glioblastoma in newly opened City of Hope clinical trial.

City of Hope scientists have developed and tested the first chimeric antigen receptor (CAR) T cell therapy using chlorotoxin (CLTX), a component of scorpion venom, to direct T cells to target brain tumor cells, according to a preclinical study published today (March 4, 2020) in Science Translational Medicine. The institution has also opened the first in-human clinical trial to use the therapy.

CARs commonly incorporate a monoclonal antibody sequence in their targeting domain, enabling CAR T cells to recognize antigens and kill tumor cells. In contrast, the CLTX-CAR uses a 36-amino acid peptide sequence first isolated from death stalker scorpion venom and now engineered to serve as the CAR recognition domain.

Glioblastoma (GBM), the most common type of brain tumor, is also among the most deadly of human cancers, according to the American Cancer Society. It is particularly difficult to treat because the tumors are disseminated throughout the brain. Efforts to develop immunotherapies, including CAR T cells, for GBM must also contend with a high degree of heterogeneity within these tumors.

For the study, City of Hope researchers used tumor cells in resection samples from a cohort of patients with GBM to compare CLTX binding with expression of antigens currently under investigation as CAR T cell targets, including IL13R2, HER2 and EGFR. They found that CLTX bound to a greater proportion of patient tumors, and cells within these tumors.

CLTX binding included the GBM stem-like cells thought to seed tumor recurrence. Consistent with these observations, CLTX-CAR T cells recognized and killed broad populations of GBM cells while ignoring nontumor cells in the brain and other organs. The study team demonstrated that CLTX-directed CAR T cells are highly effective at selectively killing human GBM cells in cell-based assays and in animal models without off-tumor targeting and toxicity.

Our chlorotoxin-incorporating CAR expands the populations of solid tumors potentially targeted by CAR T cell therapy, which is particularly needed for patients with cancers that are difficult to treat such as glioblastoma, saidChristine Brown, Ph.D., City of Hopes Heritage Provider Network Professor in Immunotherapy and deputy director of T Cell Therapeutics Research Laboratory. This is a completely new targeting strategy for CAR T therapy with CARs incorporating a recognition structure different from other CARs.

Michael Barish, Ph.D., City of Hope professor and chair of the Department of Developmental and Stem Cell Biology, initiated the development of a CAR using chlorotoxin to target GBM cells. The peptide has been used as an imaging agent to guide GBM resection surgery, and to carry radioisotopes and other therapeutics to GBM tumors.

Much like a scorpion uses toxin components of its venom to target and kill its prey, were using chlorotoxin to direct the T cells to target the tumor cells with the added advantage that the CLTX-CAR T cells are mobile and actively surveilling the brain looking for appropriate targets, Barish said. We are not actually injecting a toxin, but exploiting CLTXs binding properties in the design of the CAR. The idea was to develop a CAR that would target T cells to a wider variety of GBM tumor cells than the other antibody-based CARs.

The notion is that the higher the proportion of tumor cells that one can kill at the beginning of treatment, the greater the probability of slowing down or stopping GBM growth and recurrence, Barish added.

Dongrui Wang, a doctoral candidate in City of Hopes Irell & Manella Graduate School of Biological Sciences, was the lead scientist to establish and optimize the CLTX-CAR T cell platform and to determine that cell surface protein matrix metalloprotease 2 is required for CLTX-CAR T cell activation. He added that while people might think the chlorotoxin is what kills the GBM cells, what actually eradicates them is the tumor-specific binding and activation of the CAR T cells.

Based on the promising findings of this study, the study team intends to bring this therapy to patients diagnosed with GBM with the hope of improving outcomes against this thus far intractable cancer. With recently granted Food and Drug Administration approval to proceed, the first-in-human clinical trial using the CLTX-CAR T cells is now screening potential patients.

Reference: Chlorotoxin-directed CAR T cells for specific and effective targeting of glioblastoma by Dongrui Wang, Renate Starr, Wen-Chung Chang, Brenda Aguilar, Darya Alizadeh, Sarah L. Wright, Xin Yang, Alfonso Brito, Aniee Sarkissian, Julie R. Ostberg, Li Li, Yanhong Shi, Margarita Gutova, Karen Aboody, Behnam Badie, Stephen J. Forman, Michael E. Barish3 and Christine E. Brown, 4 March 2020, Science Translational Medicine.DOI: 10.1126/scitranslmed.aaw2672

This work was supported by the Ben & Catherine Ivy Foundation of Scottsdale, Arizona, and the clinical trial will be supported by The Marcus Foundation of Atlanta.

City of Hope, a recognized leader in CAR T cell therapies for glioblastoma and other cancers, has treated nearly 500 patients since its CAR T program started in the late 1990s. The institution continues to have one of the most comprehensive CAR T cell clinical research programs in the world it currently has 29 ongoing CAR T clinical trials, including CAR T trials for HER-2 positive breast cancer that has spread to the brain, and metastatic prostate cancer in the bones. It was the first and only cancer center to treat GBM patients with CAR T cells targeting IL13R2, and the first to administer CAR T cell therapy locally in the brain, either by direct injection at the tumor site, through intraventricular infusion into the cerebrospinal fluid, or both. In late 2019, City of Hope opened a first-in-human clinical trial for patients with recurrent glioblastoma combining IL13R2-CAR T cells with checkpoint inhibitors nivolumab, an anti-PD1 antibody, and ipilimumab, blocking the CTLA-4 protein.

Read more:
Scorpion Venom Used to Direct T Cells to Target Brain Cancer Tumors - SciTechDaily

Cell Biology

Bruker Receives Notification from Nasdaq Related to Delayed Annual Report on Form 10-K – Yahoo Finance

Bruker Corporation (Nasdaq: BRKR) today announced that it received a letter from the Listing Qualifications Department of The Nasdaq Stock Market LLC ("Nasdaq") indicating that, as a result of Brukers delay in filing its Annual Report on Form 10-K for the fiscal year ended December 31, 2019 (the "Form 10-K"), Bruker is not in compliance with the timely filing requirement for continued listing under Nasdaq Listing Rule 5250(c)(1). The notification letter has no immediate effect on the listing or trading of Brukers common stock on the Nasdaq Global Select Market.

Bruker filed a Notification of Late Filing on Form 12b-25 on March 3, 2020, indicating that the filing of the Form 10-K would be delayed pending completion of an internal investigation into an allegation recently received in connection with Brukers year-end close, primarily relating to income tax matters including the effective income tax rate for 2019 and the related income tax balance sheet accounts.

Nasdaq has informed Bruker that it must submit a plan of compliance (the "Plan") within 60 calendar days of receipt of the letter, or no later than May 4, 2020, addressing how it intends to regain compliance with Nasdaqs listing rules and, if Nasdaq accepts the Plan, it may grant an extension of up to 180 calendar days from the Form 10-K original filing due date, or until August 31, 2020, to regain compliance.

Bruker is working diligently and intends to file the Form 10-K as promptly as reasonably practicable after the conclusion of the investigation and within the 60-day period described above, which would eliminate the need for Bruker to submit a formal plan to regain compliance.

About Bruker Corporation (Nasdaq: BRKR)

Bruker is enabling scientists to make breakthrough discoveries and develop new applications that improve the quality of human life. Brukers high-performance scientific instruments and high-value analytical and diagnostic solutions enable scientists to explore life and materials at molecular, cellular and microscopic levels. In close cooperation with our customers, Bruker is enabling innovation, improved productivity and customer success in life science molecular research, in applied and pharma applications, in microscopy and nanoanalysis, and in industrial applications, as well as in cell biology, preclinical imaging, clinical phenomics and proteomics research and clinical microbiology. For more information, please visit: http://www.bruker.com.

Forward Looking Statements

Any statements contained in this press release which do not describe historical facts may constitute forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, including statements regarding the expected timing for the filing of the Form 10-K, the Companys ability to regain compliance with the Nasdaq requirements for continued listing and related matters. Any forward-looking statements contained herein are based on current expectations, but are subject to risks and uncertainties that could cause actual results to differ materially from those indicated, including, but not limited to, risks and uncertainties relating to the outcome of the previously announced internal investigation, the failure of the Company to file the Form 10-K on its expected timeline and, and other risk factors discussed from time to time in our filings with the Securities and Exchange Commission, or SEC. These and other factors are identified and described in more detail in our filings with the SEC, including, without limitation, our annual report on Form 10-K for the year ended December 31, 2018. We expressly disclaim any intent or obligation to update these forward-looking statements other than as required by law.

View source version on businesswire.com: https://www.businesswire.com/news/home/20200305005878/en/

Contacts

Miroslava MinkovaDirector, Investor Relations & Corporate DevelopmentBruker CorporationT: +1 (978) 6633660, ext. 1479E: Investor.Relations@bruker.com

Go here to see the original:
Bruker Receives Notification from Nasdaq Related to Delayed Annual Report on Form 10-K - Yahoo Finance

Cell Biology

Molecular Signature of Young-Onset Parkinson’s Disease Is… : Neurology Today – LWW Journals

Article In Brief

A unique molecular structureevident in induced pluripotent stem cells taken from people with young-onset Parkinson's diseasesuggests that the defects may be present throughout patients' lives, and that they could therefore be used as diagnostic markers.

Induced pluripotent stem cells (iPSCs) taken from patients with young-onset Parkinson's disease (YOPD) and grown into dopamine-producing neurons displayed a molecular signature that was corrected in vitro, as well as in the mice striatum, by a drug already approved by the US Food and Drug Administration (FDA), a study published in the January 27 online edition of Nature Medicine found.

Although the patients had no known genetic mutations associated with PD, the neurons grown from their iPSCs nonetheless displayed abnormally high levels of soluble alpha-synucleina classic phenotype of the disease, but one never before seen in iPSCs from patients whose disease developed later in life. Surprisingly, for reasons not yet understood, the cells also had high levels of phosphorylated protein kinase C-alpha (PKC).

In addition, the cells also had another well-known hallmark of PD: abnormally low levels of lysosomal membrane proteins, such as LAMP1. Because lysosomes break down excess proteins like alpha-synuclein, their reduced levels in PD have long been regarded as a key pathogenic mechanism.

When the study team tested agents known to activate lysosomal function, they found that a drug previously approved by the FDA as an ointment for treating precancerous lesions, PEP005, corrected all the observed abnormalities in vitro: it reduced alpha-synuclein and PKC levels while increasing LAMP1 abundance. It also decreased alpha-synuclein production when delivered to the mouse striatum.

Unexpectedly, however, PEP005 did not work by activating lysosomal function; rather, it caused another key protein-clearing cellular structure, the proteasome, to break down alpha-synuclein more readily.

The findings suggest that the defects seen in the iPSCs are present throughout patients' lives, and that they could therefore be used as diagnostic markers. Moreover, the drug PEP005 should be considered a potentially promising therapeutic candidate for YOPD and perhaps even for the 90 percent of PD patients in whom the disease develops after the age of 50, according to the study's senior author, Clive Svendsen, PhD, director of the Cedars-Sinai Board of Governors Regenerative Medicine Institute and professor of biomedical sciences and medicine at Cedars-Sinai.

These findings suggest that one day we may be able to detect and take early action to prevent this disease in at-risk individuals, said study coauthor Michele Tagliati, MD, FAAN, director of the movement disorders program and professor of neurology at Cedars-Sinai Medical Center.

But the study still raises questions regarding the biological mechanisms, and certainly does not warrant off-label prescribing of PEP005 at this time, said Marco Baptista, PhD, vice president of research programs at the Michael J. Fox Foundation, who was not involved with the study.

Repurposing PEP005 is a long way away, Dr. Baptista said. This is not something that neurologists should be thinking about prescribing or recommending to their patients.

Accumulation of alpha-synuclein has been seen in iPSC-derived dopaminergic cultures taken from patients with known genetic defects, but such defects account for only about 10 percent of the PD population. In those without known mutations, on the other hand, no defects in iPSC-derived dopamine-producing neurons have been seen. Until now, however, such studies had been conducted only in patients who had developed PD after age 50.

My idea was why to look in young-onset patients, said Dr. Svendsen.

The idea paid off more richly than he expected. We were shocked to find a very, very prominent phenotype, a buildup of alpha-synuclein, in the neurons of these patients who are genetically normal, Dr. Svendsen said. None of the controls had a buildup of synuclein, and all but one of the early PD patients had a twofold increase in it.

The signature is so consistent, he said, that it offers a natural model that can be interrogated to further understand its workings.

Because high levels of PKC were also seen, Dr. Svendsen said, We picked a bunch of drugs known to reduce PKC. We found one, PEP005, which is actually extracted from the milkweed plant, and it completely reduced synuclein levels almost to normal in dopaminergic neurons. And it also increased dopamine levels in those cells, so we got two for one.

After observing the effects of PEP005 in vitro, We put it into the mouse brain and found it reduced synuclein in vivo, Dr. Svendsen said. But we had to infuse it right into the brain. We're now trying to work out how to get it across the blood-brain barrier more efficiently.

To determine how PEP005 lowers cellular levels of alpha-synuclein, his group tested whether it was activating the lysosome, but found to their surprise that it did not do this until after the synuclein had already been degraded.

Then we asked whether it could be the proteosome, which also breaks down proteins but normally doesn't break down synuclein, Dr. Svendsen said. But when we applied PEP005, it did activate the proteasome. So we think that might be the mechanism.

Because the drug is currently applied externally, Dr. Svendsen said, the next step will be to see if it crosses the blood-brain barrier when applied to the skin of mice, and whether that results in a lowering of synuclein levels in dopaminergic neurons.

Justin Ichida, PhD, the Richard N. Merkin assistant professor of stem cell biology and regenerative medicine at the USC Keck School of Medicine, said the findings are quite important in the field. The potential diagnostic tools they made could be important in clinical care. And identifying a drug that may very effectively reverse the disease in neurons is a very important discovery.

He wondered, however, whether the increase in alpha-synuclein is truly specific to Parkinson's neurons or if it would also be seen in iPSC neurons from patients with Alzheimer's disease or amyotrophic lateral sclerosis.

I wonder if alpha-synuclein accumulating is a sign of PD in a dish or is a consequence of neurodegeneration or impaired protein degradation in general, Dr. Ichida said. That's a key question if you want to use this molecular signature as a diagnostic tool.

He also questioned if proteins other than alpha-synuclein, such as tau, would also be seen to accumulate in the iPSCs of YOPD patients.

If one of the protein-clearance mechanisms in the cell is working poorly, you would imagine that other things would also accumulate, Dr. Ichida said.

In response, Dr. Svendsen said that while some proteins other than alpha-synuclein were reported in the paper at increased levels, We did not look at tau specifically, but are in the process of looking right now. It could be that synuclein and some other proteins are somehow altered to evade them from being degraded by the lysosome, or that there is a general lysosomal problem.

Patrik Brundin, MD, PhD, director of the Center for Neurodegenerative Science and Jay Van Andel Endowed Chair at Van Andel Research Institute in Grand Rapids, MI, called the paper very interesting and thought-provoking. If these findings hold up, they could shift our understanding of young-onset PD. They imply that there is a strong genetic component that has not been picked up in prior genetic studies.

Dr. Brundin said he would like to see the results replicated in another lab using different sets of reagents. It is so intriguing and rather unexpected that one wonders if the observations really apply, as the study states, to 95 percent of all YOPD.

He also questioned whether all the young-onset PD patients are similar. Clearly the iPSCs studied here are not monogenetic PD, so they must be very diverse genetically and still all have the same alpha-synuclein change.

Dr. Brundin also asked why the abnormalities seen in YOPD neurons have not previously been seen in older cases of PD. Is there a specific cutoff regarding age-of-onset when these purposed genetic differences apply? he asked.

Dr. Svendsen responded: We don't know why the YO have this phenotype or exactly what the cut off is. We have, however, looked at one adult-onset case that did not show this phenotype. Also, one of our YO cases did not show this phenotype. Thus some patients even with early onset may not have it. We are currently testing many more cases from older-onset patients.

Dr. Brundin also wanted to know whether non-dopaminergic neurons have the same deficits described in the study.

We don't know which neurons specifically have the protein deficit as we cannot do single-cell proteomics, Dr. Svendsen answered. It could be a little in all cells or a lot in a small set. Immunocytochemistry is not quantitative but showed that it is more likely a general increase in synuclein and not specific to dopaminergic neurons.

While the findings in iPSCs suggest that the abnormal levels of alpha-synuclein must be present at birth, Dr. Brundin said, I do not know how to reconcile the present findings with genetic data.

The absence of previously described mutations in the YOPD patients means only that more work must be done to uncover the genetic underpinnings, Dr. Svendsen said.

We're just at the tip of the iceberg with understanding the genome, he said. It's such a bizarrely complex beast. Perhaps there are a thousand different proteins interacting to stop the synuclein from being degraded. In 10 years, we probably will be clever enough to see it. We know it must be there. Now the genome guys will go after it.

Dr. Baptista from the Michael J. Fox Foundation said he agreed with the view that there must be genetic alterations underpinning the defects seen in the iPSCs.

Just because we call something non-genetic could simply reflect the current ignorance of the field, he said. I think the discoveries are simply difficult to make.

He added that he wished that the main comparator in the study was not healthy controls, and that there were more older-onset iPSCs to compare against YOPD patients' samples.

Dr. Svendsen said it could be that the iPSCs from older-onset patients might yet be found with additional study to display abnormalities similar to those seen in YOPD.

Right now we only see it in young onset, he said. We may need to leave the cultures longer to see in the older-onset patients. We are doing those experiments now.

Drs. Tagliati and Svendsen disclosed that an intellectual patent is pending for diagnostic and drug screening for molecular signatures of early-onset Parkinson's disease. Dr. Ikeda is a co-founder of AcuraStem Inc. Dr. Brundin has received commercial support as a consultant from Renovo Neural, Inc., Lundbeck A/S, AbbVie, Fujifilm-Cellular Dynamics International, Axial Biotherapeutics, and Living Cell Technologies. He has also received commercial support for research from Lundbeck A/S and Roche and has ownership interests in Acousort AB and Axial Biotherapeutics. Dr. Baptista had no disclosures.

More:
Molecular Signature of Young-Onset Parkinson's Disease Is... : Neurology Today - LWW Journals

Cell Biology

Service Center staff encourages students to perform random acts of kindness throughout the week – Ke Alakai

Photo by Keyu Xiao

From writing a kind person's name on the sidewalk with chalk to sharing a genuine smile or an appreciation message to their friends, BYUHawaii students said they participated in the Random Acts of Kindness Week by looking outward and serving others by small and simple means. Students shared thoughts and feelings of happiness by being both the giver and the receiver of these acts.

The Service Center hosted activities to inspire students to perform acts of kindness, said Danilo Mantilla, a senior from Colombia majoring in marketing.

A booth outside of the Joseph F. Smith Library was set up on Feb. 8 where students could write with chalk on the ground about someone who had been kind to them, take a picture, and then send it to the person. Different groups participated, including tours of Japanese students. Students spent time writing one or more names. Mantilla expressed, If we reminded ourselves of how grateful we are for people, the list would be endless, but the chalk wasnt.

Alyssa Allen, a senior from Colorado majoring in humanities, commented, [Random Acts of Kindness] is a national event that happens every year," but she thought "it is the first time BYUHawaii has done it.

Mantilla shared an experience when a friend randomly reached out to him. That feeling of somebody doing something kind for me without me asking ... or without me being present, [it was] something I had never experienced.

The giver

Mahori Eteru, a sophomore from Australia majoring in communications and psychology, said he enjoyed the activity because it lit my day. It is so easy to compare ourselves to others, looking at grades or looking at people next to us, but we looked at people who bless our lives.

He described the way he felt as, All my stress was alleviated, and it cleared my mind ... It made me so happy. I wanted to keep going.

Darby Riley, a sophomore from Utah majoring in molecular and cell biology, said she made the effort during the week to smile at everyone she saw and reach out to those she didnt know. She said, Its easy to do something good for somebody you know, but to do something kind for somebody you dont know takes a step out of the comfort zone. It reminds me of how the Savior works. He didnt just help people He knew, but He was kind to everyone.

It doesnt take a lot of time. I find I am less stressed [when I serve], and I have enough time to get everything I need done. I feel better.

Mantilla shared, Once you get into the world of service, your mind shifts into something else. You forget about yourself and think of others.

Mark Maslar, a sophomore from California majoring in theater education, said, If you invest in doing something kind or remembering something someone else did, then you feel that nice, tender feeling inside and feel it was worth [it].

The receiver

Eteru shared he had his name written down by someone else for being kind. It encouraged me to remember Im doing better than I think Im doing. It feels nice to be appreciated and it was a unique way to do it, said Eteru.

Riley said she had her name written down a total of five times. She shared, I dont think Im the kindest person. I think the people who are usually the most outgoing ... often have an inner struggle with themselves, so it is nice to see [acknowledgment] one in a while.

Sometimes we can beat up ourselves, and we can feel like we're not doing enough. Then, when other people reach out and say, Youre so kind, or Thank you for being there for me, It makes me feel better and [I think], Im doing okay. Im not perfect, but at least I made somebody smile.

Sister Kim Olsen, a senior missionary serving in the Leadership Office with her husband, said, I saw a student folding butterfly origami. They then showed up on the Random Acts of Kindness table outside the Service Center. It is stuff like that, that makes people smile.

Service beyond Random Acts of Kindness Week

Allen said she hopes its something the students can hold onto in their hearts, not just for a week, but a whole year. I hope to build awareness of kindness. I feel kindness goes beyond just our actions. Its also our thoughts and hearts. That would be mission accomplished.

For more information on local service opportunities, visit the Service Center or go online to justserve.org.

Read more:
Service Center staff encourages students to perform random acts of kindness throughout the week - Ke Alakai

Cell Biology

Edited Transcript of NKTR earnings conference call or presentation 27-Feb-20 10:00pm GMT – Yahoo Finance

SAN FRANCISCO Mar 6, 2020 (Thomson StreetEvents) -- Edited Transcript of Nektar Therapeutics earnings conference call or presentation Thursday, February 27, 2020 at 10:00:00pm GMT

* Gilbert M. Labrucherie

* Howard W. Robin

Oppenheimer & Co. Inc., Research Division - Executive Director & Senior Analyst

Ladies and gentlemen, thank you for standing by, and welcome to the Nektar Therapeutics Fourth Quarter 2019 Financial Results Conference. (Operator Instructions) Please be advised that today's conference is being recorded.

(Operator Instructions) I would now like to hand the conference over to your speaker today, Ms. Jennifer Ruddock, Head of Corporate Affairs. Ma'am, you may begin.

Thank you, Crystal. Good afternoon, everyone, and thank you for joining us today. With us are Howard Robin, our President and CEO; Gil Labrucherie, our COO and CFO; Dr. Jonathan Zalevsky, our Head of R&D; and Dr. Wei Lin, our Head of Development.

On today's call, we expect to make forward-looking statements regarding our business, including clinical trial results, timing and plans for future clinical trials, timing and plans for future clinical data presentations at medical meetings, the therapeutic potential of our drug candidates, outcomes and plans for health authority regulatory actions and decisions, financial guidance and certain other statements regarding the future of our business. Because these statements relate to the future, they are subject to inherent uncertainties and risks that are difficult to predict and many of which are outside of our control.

Important risks and uncertainties are set forth in our Form 10-Q that we filed on November 7, 2019, which is available at sec.gov.

We undertake no obligation to update any of these statements, whether as a result of new information, future developments or otherwise. A webcast of this call will be available on the IR page at Nektar's website at nektar.com.

With that, I will now hand the call over to our President and CEO, Howard Robin. Howard?

Howard W. Robin, Nektar Therapeutics - CEO, President & Director [3]

Thank you, Jennifer, and thank you to everyone for joining us on the call today. On today's call, we will provide an update on our pipeline compounds, which include our I-O pipeline of Nektar IL-2, IL-15 and TLR agonist candidates and our immunology program NKTR-358. We will also review our planned upcoming milestones for these programs and provide our financial guidance for 2020. But before I discuss the advancements we made with our I-O and immunology portfolio, I'd like to briefly cover some challenges we faced this year that are outside of the core focus of our pipeline.

Starting with NKTR-181. As you know, we made a strategic decision last month to withdraw the NDA for NKTR-181. The NKTR-181 ADCOM was the first of several that week that were negative for the opioid class, and it became clear from these discussions that the bar for approval of any opioid compound is much higher than what was established by approvals in the past.

Additionally, since that time that we submitted our NDA, the liability in the opioid class has become a significant consideration, with numerous lawsuits filed against opioid manufacturers and distributors. And based upon all of these factors, we made a business decision that further investment could not be justified for a medicine in this class, which would have been at the expense of sacrificing important developmental work for our immuno-oncology pipeline. As we look back at our successful development efforts for this program, I want to thank our team for their hard work, thank the patients and physicians who participated in our clinical trials, some of whom came to speak at the ADCOM. We did not take this decision lightly, but believe it is the appropriate action to take as we focus on the advancement of our I-O and immunology pipeline.

Secondly, as you know, we were conducting the ATTAIN study for our chemotherapy agent, ONZEALD, in advanced breast cancer patients who also have brain metastases, which compared ONZEALD to a chemo agent of choice in these patients.

The ATTAIN study was being partially funded from a former partnership we had with Daiichi Sankyo. And you'll recall that the ATTAIN study was designed based upon a doubling of survival that we saw in a subset of patients from the earlier BEACON study of ONZEALD in advanced breast cancer patients with brain mets as compared to chemotherapy of physician's choice.

The primary analysis of the ATTAIN study was completed late last week. And while ONZEALD performed at least as well as the physician's choice standard of care for PFS and OS, the study endpoint of improvement in overall survival was not met. As a result, we're planning no further clinical work on ONZEALD, and we're grateful to the patients and their families who participated in the ATTAIN study.

With these actions behind us, our company is highly focused in the core areas of immuno-oncology and immunology, where we believe we have the potential to create transformative medicines for patients. Our I-O portfolio is highly differentiated with 2 strong cytokine programs, IL-2 with bempeg and IL-15 with NTKR-255 and a small molecule TLR agonist program. This unique portfolio allows us to capture opportunities that span both solid and liquid tumors. In immunology, NKTR-358 is advancing into several clinical studies in multiple autoimmune conditions, the first of which are lupus, atopic dermatitis and psoriasis, and I'll talk more about those later on the call.

Let me first start with bempeg, our IL-2 pathway program in T cell stimulator. Earlier this year, we announced a revised collaboration agreement with our partner, BMS. Under the new joint development plan, we expanded the BMS-Nektar active registrational programs for the doublet of bempeg and nivo from the 3 studies that were underway to now include 7 studies in first-line and adjuvant settings, across 4 tumor types with more than 3,000 patients. The new registrational program builds upon the opportunity in melanoma, bladder cancer and renal cell carcinoma, and also adds plans for a Phase II study in first-line non-small cell lung cancer.

In addition to the 3 ongoing Registrational Trials in first-line metastatic melanoma, first-line cis-ineligible metastatic bladder cancer and first-line metastatic RCC, we've already launched a new Phase III study in muscle-invasive bladder cancer, and we are initiating a Phase III study in adjuvant melanoma. I will let Wei cover the design of these new Phase III studies in a moment.

The economics of the revised agreement reflect BMS's continued commitment to the collaboration. At a high level, if you look at BMS's share of clinical costs for the new joint development plan associated with the 7 studies, it is approximately $1.2 billion. There were also some enhancements to the economics for Nektar, which provide additional and accelerated near-term milestone payments. This includes a $25 million accelerated milestone payment that we received in Q1 of this year with the initiation of the MIBC study. It also includes a new $25 million milestone for Nektar at the start of the adjuvant melanoma study, which we expect will occur in Q3 of this year. In addition, the new agreement includes $75 million accelerated milestone payment at the start of the first Phase III registrational non-small cell lung cancer study with nivo. The rest of the economics are unchanged. BMS funds 2/3 of the development cost, Nektar contributes 1/3. Nektar books global revenues. The profit split is 65% Nektar, 35% to BMS. We're also entitled to $650 million in total milestone payments upon the first approvals of bempeg in U.S., Europe and Japan, and then $260 million per each of the next 3 approved indications for bempeg.

As many of you know, BMS is currently enrolling patients in our Registrational Trial in first-line metastatic melanoma, and all the investigator sites are now up and running. Last year, we obtained an FDA breakthrough therapy designation for bempeg plus nivo in patients with metastatic melanoma, based on the positive data, including complete response rate from our PIVOT-02 study. The Phase III study enrolling in this setting has 3 endpoints: ORR, PFS and OS. The current projected earliest time line for reaching the follow-up time period needed on the number of patients required for the first interim ORR endpoint is the end of Q4 2020 this year.

The PFS endpoint is projected to occur roughly 6 to 7 months later. But as a reminder, this is event-driven, and the timing could change. For both OOR and PFS, the results will be analyzed by blinded independent radiology review. So also keep in mind that this process will affect timing for the completion of any data analysis. So the first data readout will most likely be Q1 of '21. As we head closer, we should be able to refine this time line. As a reminder, ORR is designed as an accelerated approval endpoint. We spent only a small amount of alpha on this, and PFS is the full approval endpoint.

With the breakthrough designation, the potential for the doublet in melanoma is quite promising. And as part of our amended agreement with BMS, our 2 companies are excited to expand our development efforts into the adjuvant melanoma setting. This essentially doubles the number of patients that could potentially benefit from this doublet in melanoma and represents a significant opportunity for bempeg. Given BMS has the leadership position with nivolumab across all lines of therapy in melanoma, we're pleased that bempeg with nivolumab has the potential to further advance the standard of care in both early and advanced stage melanoma.

In bladder cancer, we are enrolling a 200-patient study in first-line cis-ineligible bladder cancer, which is intended to support a potential accelerated approval pathway in this setting, specifically in patients with PD-L1 low expression as defined by a CPS score under 10. We expect the first potential data on the ORR endpoint from this trial in Q2 or Q3 of '21. And to build on this opportunity in bladder cancer, we've also initiated a confirmatory Phase III study in patients with cis-ineligible muscle-invasive bladder cancer. This gives us the ability to capture the opportunity in both early and late-stage bladder cancer, expanding the potential for bempeg and nivo to help even more patients.

In metastatic first-line renal cell carcinoma, BMS and Nektar have chosen a comprehensive approach that positions the doublet with a TKI sparing and a TKI inclusive regimen. Our Phase III Registrational Study evaluating bempeg and nivo versus a TKI in first-line RCC is now enrolling nicely, and we are on track to potentially have the first interim OS readout in the first quarter of 2022.

The TKI inclusive regimen development work will start mid-year under the new BMS agreement and is designed to support a registrational path forward in a first-line metastatic RCC study with this triplet.

We will conduct a Phase I/II dose escalation and expansion study to evaluate bempeg plus nivo in combination with axi in first-line RCC to establish the dose and administration schedule for a future Registrational Trial.

Finally, BMS and Nektar agreed on a development path for the doublet in first-line non-small cell lung cancer that we believe positions bempeg nicely for a flexible registrational path forward in non-small cell lung cancer. BMS will run a dose optimization and expansion study to identify the appropriate dose regimen, and BMS is paying 100% of the cost of that program. And we will continue our work evaluating pembro with bempeg in non-small cell lung cancer in our PROPEL trial, which is currently enrolling patients. This gives us the flexibility in the future to evaluate moving forward with either nivo or pembro in non-small cell lung cancer.

We're pleased to have the renewed agreement in place and look forward to this phase of our collaboration. This structure also removes certain exclusivity restrictions from the old agreement for a list of indications for bempeg and so provides us enhanced flexibility to pursue other combinations for bempeg.

Along those lines, we're exploring the potential of bempeg with other checkpoint inhibitors and other mechanisms and expanding this work is a key role for us this year.

In collaboration with Pfizer, we have an ongoing Phase Ib/II study in head and neck cancer and castration-resistant prostate cancer. The study will evaluate bempeg and nivolumab in head and neck cancer and also evaluate 2 triplet combinations, bempeg plus avelumab plus talazoparib; and bempeg and avelumab and enzalutamide in prostate cancer.

We're very excited to work with Pfizer on this because of the opportunity in these 2 solid tumor settings for bempeg, particularly in patients with PD-L1 negative tumors. We also started a study in head and neck cancer in partnership with Vaccibody. The study combines bempeg with their personalized vaccine approach and could pave the way for a novel treatment regimen with bempeg in this tumor setting.

In addition, we have plans to start a study with BioXcel, combining their molecule, bempeg and Pfizer's avelumab in pancreatic cancer. As you can see, the bempeg program is emerging as 1 of the largest registrational and development programs in immuno-oncology, and we're excited about the potential of this novel agent to combine with checkpoints and other mechanisms.

Turning to our next immuno-oncology candidate, NKTR-262, our TLR7/8 agonist, our Phase I/II REVEAL study is advancing, and we recently achieved our recommended Phase II dose of NKTR-262 with bempeg. You'll recall that because this was a novel-novel combination, we had to evaluate staged dosing of NKTR-262 with bempeg in dose escalation. We've observed high levels of TLR activation in the tumor microenvironment and the dose escalation allows us to understand PK/PD and then characterize safety for NKTR-262.

Our current plan is to take the recommended Phase II dose of NKTR-262 into a focused expansion in at least 1 tumor type, starting with 24 relapsed and refractory melanoma patients. Based upon the biology of the innate and adaptive immune system interaction, we will now evaluate simultaneous dosing of the TLR and bempeg to explore the combination's potential in the I-O relapsed/refractory melanoma setting.

The scientific community is beginning to recognize the importance of natural killer cell biology in the treatment of cancer. And as many of you know, this area of research is generating much excitement.

So let me now turn to our newest clinical candidate, our IL-15 agonist program known as NKTR-255. NKTR-255 is designed to capture the full biology of the IL-15 pathway to cause both proliferation of NK cells and the expansion of CD8 memory cells, which provides us with a wide range of potential development pathways for NTKR-255.

Given the product profile, we're advancing towards forward on multiple fronts with this program and JZ will provide more details on the data emerging from this program, but let me provide a high-level overview of the progress on this promising mechanism. First, we're enrolling patients into our first-in-human clinical trial of NKTR-255, which began last year. The study is evaluating NKTR-255, first as a monotherapy, and then in combination with dara or rituximab in multiple myeloma and non-Hodgkin's lymphoma, respectively. In addition, we have 2 research collaborations ongoing with partners who are entirely funding the research. First, Janssen is conducting preclinical studies of NKTR-255 in combination with a number of their internal oncology mechanisms. And separately, in virology, Gilead is exploring the potential of NKTR-255 in nonhuman primate studies, in combination with a number of antivirals in their portfolio. So NKTR-255 has the potential to have many applications in oncology as well as, potentially, virology, and we look forward to its progress.

Moving on to NKTR-358, our Treg stimulatory program, which is partnered with Lilly. We reported significant progress with this program in 2019. Last year, first-in-human data in healthy volunteers were reported at EULAR, and these data demonstrated the candidate's dose-dependent and selected proliferation of Treg cells. We recently completed the Phase Ib multiple ascending dose study in lupus patients, and we have submitted these data to be presented at this year's EULAR meeting.

Our partner, Lilly, also recently initiated Phase Ib studies in 2 new autoimmune indications of psoriasis and atopic dermatitis, and these studies are ongoing and enrolling patients. Our partner, Lilly, also has plans to start a Phase II dose-ranging study in lupus in the middle of this year, and they plan to add another Phase II autoimmune indication to the development program this year.

So we're very pleased with their commitment and the broad nature of this development program, which reflects the potential of this novel mechanism to treat autoimmune diseases. And with that, I'd like to turn the call over to Wei to review the Phase III study design for bempeg. Wei?

--------------------------------------------------------------------------------

Wei Lin, Nektar Therapeutics - SVP & Head of Development [4]

--------------------------------------------------------------------------------

Thank you, Howard. I'd like to discuss briefly the comprehensive plan we've developed with our partner, BMS, for the doublet of bempeg plus nivolumab in the melanoma setting, an area where the IL-2 pathway has already been validated. As Howard stated, we have generated breakthrough designation-worthy data in first-line metastatic melanoma from our PIVOT-02 study of bempeg plus nivo. At a median follow-up of approximately 18 months, 34% of patients had a complete response as determined by blinded independent central review; 42% had a 100% reduction in target lesions; and 47%, almost half, had a greater than 75% reduction in target lesions.

The significance of deep responses in metastatic melanoma and its association with survival have recently been demonstrated by the FDA in a metanalysis they presented at ASCO 2019. Based on this analysis, patients who achieved a 75% or greater tumor shrinkage in their RECIST targ lesions, including patients that achieved a complete response, had very high likelihood of having the greatest improvement in progression-free survival and overall survival, especially if they were treated with immunotherapy. So objective response is very highly correlated with survival in melanoma with I-O agents.

With that context, our data from the PIVOT-02 study showing that nearly 1/2 of the melanoma patients had a 75% or greater response reinforces our confidence in the doublet in melanoma. And indeed, as we presented in November at SITC 2019, with approximately 18 months of follow-up, median PFS had not been reached. We plan to share updated data from this cohort at a future meeting in the second half of this year.

Our confidence in the potential clinical benefit that bempeg plus nivo may offer in melanoma has led us and BMS to initiate a study in the adjuvant setting. In this study, we evaluate the extended treatment of post-surgical patients with bempeg plus nivo with an endpoint of event-free survival.

The treatment duration will be 12 months. We estimate that the study will enroll between 900 and 1,000 patients and will compare the doublet of bempeg plus nivo to a single-agent nivolumab. We are finalizing the protocol with BMS and expect to start this trial in the second half of this year. Due to the long duration of adjuvant melanoma studies, we expect a potential first readout in 2024.

With the ongoing Phase III metastatic melanoma study and the new adjuvant study, BMS and Nektar now have a comprehensive approach to expanding the transformative potential of the bempeg/nivo doublet to more patients with melanoma. In addition, as Howard stated, in January, BMS started the new Phase III bladder cancer study, which is enrolling patients with muscle-invasive disease in the peri-adjuvant setting.

Our ongoing metastatic study in urothelial carcinoma is in the cisplatin-ineligible patients. And this new Phase III study extends our doublet into earlier disease for essentially the same patient population. In addition, the trial will also serve as the confirmatory study for a potential accelerated approval filing planned with our ongoing metastatic trial.

In the muscle-invasive study, we will stratify patients by stage and PD-L1 status. During the new adjuvant pre-surgical phase, 540 patients will be randomized into 3 arms to receive treatment with either bempeg plus nivo or nivo or no treatment at all, which is the current standard of care. Then after cystectomy, they will continue on the same pre-surgical treatment regimen for a 12-month period.

The primary endpoint will be pathologic complete response and event-free survival.

Again, this is a longer study and our first potential readout is expected to be in 2024. With that, I'll hand the call to JZ to discuss more on our NTKR-255 program.

--------------------------------------------------------------------------------

Jonathan Zalevsky, Nektar Therapeutics - Chief Research & Development Officer [5]

--------------------------------------------------------------------------------

Thanks, Wei. I'd like to spend a little more time discussing the IL-15 program, NKTR-255, as it is the next large cytokine program in our pipeline that is generating significant interest. NKTR-255 was designed to capture the full biology of the IL-15 pathway. Specifically meaning that NKTR-255 is designed to capture all the receptor ligand interactions available through targeting the IL-15 agonist pathway. As a consequence, NKTR-255 functions as a significant expander of natural killer cells and an agent that promotes the survival and expansion of memory CD8 T cells. The clinical and research community is increasingly recognizing the importance of NK cells and memory cells in the I-O cascade.

Now as I just stated, a key differentiating factor for NKTR-255 is that we have engineered it to bind to all forms of the IL-15 receptor versus other mutein proteins in development that only bind to beta gamma receptors. We believe that this will translate to enhanced efficacy. For example, we know that in order to support NK cell-mediated cellular killing, you need to induce intracellular granzyme B and data presented at SITC 2019 showed that we get maximal granzyme B production versus other muteins and even more than native IL-15.

Additional preclinical data we generated to date highlights the various combination opportunities for this candidate. First, we see an opportunity to combine with antibodies such as daratumumab and rituximab that work through an antibody-dependent cellular cytotoxicity or ADCC mechanism of action. In the ADCC reaction, antibodies bind to the target cell surface via the antigen recognition portion of the antibody. This coating of a cell with antigen recognizing antibodies is an immune process called opsonization. These opsonized cells are then recognized by NK cells via the Fc gamma receptors on the NK cells binding to the Fc region of antibodies on opsonized cells. The clustering of Fc gamma receptors promotes degranulation of the NK cells, leading to killing of the opsonized cells. In this way, the targeted antibody is able to selectively and specifically kill opsonized cells via the action of NK effector cells. However, one of the limitations of the ADCC reaction is that NK cells, the effector cells that actually promote the killing of opsonized cells, are consumed and themselves depleted in the ADCC reaction, consequently, limiting efficacy of the targeted antibody. If we are able to enhance the proliferation and function of NK cells by NKTR-255 and combine that with ADCC antibodies, we can see a very profound effect.

In nonclinical studies, NKTR-255 exhibited antitumor activity and substantially enhanced in vivo proliferation and activation of NK cells to provide sustained cytotoxic function.

In the preclinical lymphoma model, where single agent daratumumab was ineffective, NKTR-255 treatment in combination of daratumumab increased NK cell numbers and activity in bone marrow tissue and enhanced ADCC mediated tumor cell clearance in the bone marrow compartment. Now this is a very important result because it confirmed that NKTR-255 was able to mobilize functional NK cells in the bone marrow compartment, indicating that with NKTR-255, we can generate not only systemic, but also tissue-dependent effects.

More recently at ASH, we showed that NKTR-255 enhanced the number and function of both NK and CD8 effector memory T cell populations in the peripheral blood from healthy donors and from patients with multiple myeloma. NKTR-255 was also able to revert the inhibitory status of NK cells for multiple myeloma patients and showed synergy with daratumumab and elotuzumab to significantly increase the status of NK susceptibility of the multiple myeloma cells in a dose-dependent manner.

Collectively, these data provide a strong rationale for our first clinical study, which is now underway. The study is evaluating the safety and dose schedule of NKTR-255 as a monotherapy, and then will expand into combination with antibodies that work through an ADCC mechanism, including daratumumab and rituximab. We plan to enroll patients with relapsed or refractory multiple myeloma and non-Hodgkin's lymphoma in this study. The study will also evaluate pharmacokinetic and pharmacodynamic effects as well as antitumor activity. We have also introduced a robust biomarker program into this trial to provide a deep assessment of the NKTR-255 mechanism of action. Besides NK cells, we will also evaluate total and subpopulations of CD4 and CD8 memory T cells to study the effect of NKTR-255 on their expansion, activation and survival.

This biomarker-rich, early clinical development approach allows us to follow the science in the development and planning for NKTR-255. Our goal is to achieve initial results from the first monotherapy phase of this Phase I trial this year. In addition, our partners, Janssen and Gilead, may present data from their respective preclinical efforts with NKTR-255 as well. Now we also see potential for NKTR-255 in combination with CAR-T and other cell therapies. CAR-T is very effective, but only for a relatively short period of time. By adding IL-15 and promoting proliferation of memory T cells, we may be able to get a much more durable duration of response associated with CAR-T therapy. Our collaboration with Fred Hutchinson has yielded some impressive early data also presented at ASH. Specifically, researchers demonstrated NKTR-255 prevented tumor growth and increased survival of CAR-T cells when added to a CD19-targeted CAR-T cell regimen in models of B-cell lymphoma. With that update, let me turn the call over to Gil for a review of the financials.

--------------------------------------------------------------------------------

Gilbert M. Labrucherie, Nektar Therapeutics - Senior VP, CFO & COO [6]

--------------------------------------------------------------------------------

Thank you, JZ, and good afternoon, everyone. This afternoon, we announced our full year financial results for 2019 in our earnings press release. On this call, I will provide our annual financial guidance for 2020. Starting with our cash position, we exited 2019 with $1.6 billion of cash and investments. With our exceptionally strong cash position, we have decided to repay the $250 million of outstanding senior secured notes on our balance sheet. This will strengthen our balance sheet and improve our annual cash flow as it will result in approximately $20 million of annual interest savings on a go-forward basis. With respect to cash usage for R&D and operations, we expect to use approximately $350 million in net cash in 2020. This compares to net cash usage of $315 million in 2019. This increase in investment in 2020 is primarily a result of our plans to complete enrollment in the first-line Registrational Studies in melanoma, bladder, renal cell carcinoma as well as begin the 2 new Phase III studies we are initiating this year for the expanded bempeg development program under our BMS collaboration.

After taking account of our plan to repay the $250 million of debt in Q2, we expect to end 2020 with approximately $1 billion in cash and investments.

Now turning to revenue. Our GAAP revenue is expected to be between $140 million and $145 million this year. GAAP revenue includes $50 million of new and accelerated milestone payments from BMS under our expanded agreement. The first $25 million of these milestones will be recognized in Q1 for the start of the MIBC study, which occurred in January of this year. And the second $25 million milestone will be in connection with the start of the adjuvant melanoma study, which is currently planned for Q3. Excluding these milestones, we expect the remaining $90 million to $95 million of GAAP revenue to be fairly ratable over the 4 quarters of 2020, comprised of the following: $40 million to $42 million in cash royalties; $34 million to $36 million of noncash royalty revenue; $11 million to $12 million of product sales; and an additional $5 million in other licensed collaboration revenue outside of BMS.

We anticipate 2020 GAAP R&D expense will range between $475 million and $500 million, which includes approximately $70 million of noncash depreciation and stock compensation expense. We expect R&D expense to be fairly ratable over the 4 quarters of this year.

In addition to the R&D investment in the new trials in the expanded BMS collaboration, I would like to highlight a few other key areas of focus for us in 2020.

In order to meet our planned time line for BLA filing and potential commercial launch of bempeg in 2021, we plan to complete validation of our large-scale commercial manufacturing process and begin manufacture of commercial supplies this year. As a result, bempeg manufacturing costs will continue to be a significant component of our R&D expense in 2020.

Under our BMS collaboration, BMS shares 35% of bempeg manufacturing costs. In addition, we will continue to invest in development of bempeg outside of the BMS collaboration, including our PROPEL study with pembrolizumab in non-small cell lung cancer. And in combination with other modalities under our collaborations with Pfizer, BioXcel and Vaccibody. Our R&D expense also includes the initiation of 2 Phase II studies for NKTR-358, and the ongoing Phase Ib studies in atopic dermatitis and psoriasis. As Howard stated, the first Phase II study in lupus is planned to begin midyear, and the second Phase II study in a new autoimmune disease state will start in the second half of 2020. As a reminder, in our collaboration with Lilly, we are responsible for 25% of these costs.

In addition, we will continue to invest in our Phase I/II work for NKTR-255 and NKTR-262. G&A expense for 2020 is projected to be between $105 million and $115 million, which includes approximately $45 million of noncash depreciation and stock compensation expense. For 2020, GAAP interest income will be approximately $30 million to $33 million. With repayment of our senior notes, we expect 2020 full year interest expense of $7 million to $8 million as compared to $21.3 million in 2019. We also expect to recognize between $26 million and $28 million in noncash interest expense related to the legacy CIMZIA and MIRCERA royalty monetization. In Q1 of this year, we plan to record an impairment charge on our income statement of between $45 million and $50 million related to the discontinuation of the NKTR-181 program. This impairment charge is composed of 2 parts: noncash charges of approximately $20 million and cash payments of $25 million to $30 million, primarily related to certain non-cancelable contract manufacturing commitments.

As I stated earlier, we plan to end 2020 with approximately $1 billion in cash and investments after repayment of our $250 million in senior secured notes.

And with that, we will open the call for questions. Operator?

================================================================================

Questions and Answers

--------------------------------------------------------------------------------

Operator [1]

--------------------------------------------------------------------------------

(Operator Instructions) And our first question comes from Chris Shibutani from Cowen.

--------------------------------------------------------------------------------

Chris Shibutani, Cowen and Company, LLC, Research Division - MD & Senior Research Analyst [2]

--------------------------------------------------------------------------------

With the bempeg programs in lung, can you give us a sense for how enrollment is progressing, both with the program with OPDIVO as well as with pembro? I think historically, there have been some bumps in the road. Can you talk about what initiatives you have put in place that may be helping to engender confidence in your time lines?

--------------------------------------------------------------------------------

Wei Lin, Nektar Therapeutics - SVP & Head of Development [3]

--------------------------------------------------------------------------------

This is Wei Lin. I'll take that question. So regarding the -- our bempeg combination in lung, as been stated in the call, our strategy is really 2-prong: in combination with pembrolizumab; as well as combination with nivolumab. First of all, the combination with pembrolizumab, that's being operationalized by Nektar. And we expect -- so that study has started enrollment. And we expect by the end of the year to have 10 to 20 patients' worth of data that has a sufficient follow-up, at least 2 scans, to allow for data assessment of activity. The combination with nivolumab, that's being operationalized fully by BMS. And that study has not opened yet, and we'll provide more details as the year goes along.

--------------------------------------------------------------------------------

Chris Shibutani, Cowen and Company, LLC, Research Division - MD & Senior Research Analyst [4]

--------------------------------------------------------------------------------

Great. And then with 255, which seems to be an asset that JZ highlighted here, can you give us a sense, maybe frame what kind of efficacy results we may see in the monotherapy setting for those 2 indications that we are likely to see data, the myeloma, et cetera?

--------------------------------------------------------------------------------

Jonathan Zalevsky, Nektar Therapeutics - Chief Research & Development Officer [5]

Read more here:
Edited Transcript of NKTR earnings conference call or presentation 27-Feb-20 10:00pm GMT - Yahoo Finance

Cell Biology

The Pancreatic Cancer Collective awards additional funding of $16 million for new therapies – The Medical News

The Pancreatic Cancer Collective, the strategic partnership of Lustgarten Foundation and Stand Up To Cancer (SU2C), has awarded additional funding of up to $16 million to four teams of top researchers as part of its "New Therapies Challenge Grants," the American Association for Cancer Research (AACR), Scientific Partner of SU2C, announced today.

The additional support builds on a first round of funding announced in November 2018. These four teams originally received up to $1 million each to pursue preclinical work over 13 months, including several projects seeking to repurpose drugs approved for other uses for their potential to treat pancreatic cancer. These teams demonstrated the most promising preliminary results to allow them to take potential therapies into clinical trials. Pancreatic cancer is one of the deadliest forms of cancer, with a five-year survival rate of about 9 percent, according to the National Cancer Institute.

"These 'Challenge Grants' seeking new treatments for pancreatic cancer are working exactly as intended," said Phillip A. Sharp, PhD, the Nobel laureate and MIT scientist who serves as chair of the SU2C Scientific Advisory Committee. "These are important new investigations that have the potential to save lives with new approaches to therapy."

Each team will receive up to $4 million over a three-year term for the studies focused on clinical trials.

We are impressed by the results of the first round. Under this phased 'Challenge Grant' approach, teams are accelerating pre-clinical work and we are very eager to take the next step to bring new applications for pancreatic cancer treatment to clinical studies."

David A. Tuveson, MD, PhD, chief scientist of the Lustgarten Foundation and director of the cancer center at Cold Spring Harbor Laboratory in New York

"It is gratifying to see the initial success of the New Therapies Challenge project, which we created to accelerate the research process and bring improved treatment options to patients," said Kerri Kaplan, president and CEO of the Lustgarten Foundation. "Through the Pancreatic Cancer Collective, these two leading cancer organizations have demonstrated the strength of collaboration. We are excited for the potential for breakthroughs in effective pancreatic cancer treatments and, eventually, a cure for this deadly disease."

The AACR will support the administration of these projects receiving funding for the second round, including:

Targeting SHP2 in Pancreatic Cancer: Team leader: Rene Bernards, PhD, Netherlands Cancer Institute; co-leaders: Hana Algl, MD, PhD, Technical University of Munich, and Emile E. Voest, MD, PhD, Netherlands Cancer Institute. The team focuses on pancreatic tumors that have a mutation in the KRAS gene and has conducted preclinical testing of drug combinations that inhibit certain proteins in the malignant cells. In the second stage, the team will move into a phase I/Ib clinical trial to test the combination of SHP2 inhibitors (RMC4630) and ERK inhibitors (LY3214996). The results are expected to lay the basis for a phase II clinical trial.

Exploiting DNA Repair Gene Mutations in Pancreatic Cancer: Team leader: Alan D'Andrea, MD, Dana-Farber Cancer Institute; co-leader: James Cleary, MD, PhD, Dana-Farber Cancer Institute. The team has been seeking to evaluate DNA repair inhibitors and improve the use of PARP inhibitors, which interfere with the ability of cancerous cells to increase in number. The team's preclinical data suggests that combining gemcitabine with inhibitors that target regulatory proteins involved in DNA repair could be an effective therapy in platinum-resistant pancreatic cancer. Based on these laboratory findings, the team is developing three pancreatic cancer clinical trials testing gemcitabine-based combinations: gemcitabine/ATR inhibitor BAY1895344; gemcitabine/CHK1 inhibitor LY2880070; and gemcitabine/WEE1 inhibitor AZD1775. The most promising combinations will be identified for potential validation in larger trials.

Immunotherapy Targeting Mutant KRAS (mKRAS): Leader: Robert H. Vonderheide, MD, DPhil, Abramson Cancer Center at the University of Pennsylvania; co-leaders: Elizabeth M. Jaffee, MD, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, and Beatriz Carreno, PhD, Abramson Cancer Center at the University of Pennsylvania. The team is developing an immunological approach to target mutations in the molecule KRAS, an underlying cause of most cases of pancreatic cancer. In the first round of funding, the team used innovative strategies in bioinformatics, biochemistry, and cell biology to identify specific mKRAS protein sequences that can be recognized by T cells. They then isolated a series of molecular receptors that enable T cells to home in on cancer cells expressing mKRAS. Based on these findings, the team is conducting two different clinical trials with novel vaccines aimed at triggering mKRAS immune responses in patients with resected pancreatic cancer. In round two of funding, the team plans to use the most promising T-cell receptor identified and conduct a clinical trial of engineered T-cell therapy for patients with metastatic pancreatic cancer.

Molecularly Targeted Radionuclide Therapy via the Integrin v?6; Team Leader: Julie Sutcliffe, PhD, University of California Davis; co-leader: Richard Bold, MD, University of California Davis. The team has been working to develop a peptide receptor radionuclide therapy (PRRT) that involves homing in on a protein called integrin v6, a cell surface receptor that can be found in pancreatic cancers. The team has synthesized in the laboratory a pair of related peptide constructs that are tagged with two different radiolabels. One radiolabel facilitates the imaging of pancreatic cancer lesions in patients that can more likely benefit from the PRRT. The other radiolabel can facilitate the killing of the pancreatic cancer cells. The team has obtained promising results in the laboratory testing of the peptide constructs. In the second round of funding, the team will conduct a phase 1, first-in-human study to evaluate the feasibility, safety and efficacy of the two peptide constructs. The study will determine if one construct can detect lesions in patients with locally advanced or metastatic pancreatic cancer; establish the safety and tolerability of the pair; evaluate the maximum tolerated dose of the second construct; and, using pre-clinical models, establish an optimal dosing regimen.

The Lustgarten Foundation and Stand Up To Cancer have collaborated closely since 2012, jointly funding more than 400 investigators from nearly 70 leading research centers in the United States and the United Kingdom. These efforts include 18 multi-institutional teams, including Convergence Teams bringing together computational experts with clinical oncologists, and cancer interception -- research supporting the earliest diagnosis of pancreatic cancer, even before the cancer may have fully formed. All told, these collaborative teams have planned, started, or completed nearly 30 clinical trials. The Pancreatic Cancer Collective is building on this momentum to push the boundaries of what can be accomplished even further.

Read more:
The Pancreatic Cancer Collective awards additional funding of $16 million for new therapies - The Medical News