1985 |
Cheresh, David A |
F32Activity Code Description: To provide postdoctoral research training to individuals to broaden their scientific background and extend their potential for research in specified health-related areas. |
Properties of Melanoma Cell Surface Glycolipids @ Scripps Clinic and Research Foundation |
0.913 |
1988 — 1991 |
Cheresh, David A |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Regulation of Tumor Cell Attachment by Surface Antigens @ Scripps Clinic and Research Foundation
The main objective of this proposal is to conduct indepth studies of mechanisms underlying tumor invasion and metastasis in human melanoma. This will be accomplished by gaining a basic understanding of some of the complex processes involved in tumor-cell substratum interactions at the molecular and biological levels. Two major approaches will be employed: First, specific monoclonal and polyclonal antibodies will be used as molecular probes to characterize the structural, functional and biosynthetic properties of two distinct chemically defined antigens expressed on the human melanoma cell surface that are directly involved in the capacity of such cells to adhere to and migrate on the extracellular matrix. The target antigens include the disialogangliosides GD3 and GD2 as well as a 130/105 kDa glycoprotein adhesion receptor complex expressed on the surface of human melanoma cells. Such studies will examine the functional role of these structures in the biological properties of human melanoma cells with regard to attachment and migration on individual adhesive proteins as well as on intact extracellular matrix. Second, an experimental animal model for human melanoma metastasis will be used together with human melanoma cell lines derived from the same patient's primary and metastatic lesions to examine the in vivo significance of these antigenic structures on the surface of human melanoma cells and assess their relevance for metastatic disease. The basic rationale underlying this research proposal is that in order to metastasize a human tumor cell must be able to attach and invade normal host tissues. The extracellular matrix of normal host tissue provides the natural barrier as well as the substrate for the metastatic tumor cell. Therefore, it is imperative to gain an understanding of the molecular and biological events that take place between the tumor cell surface and the extracellular matrix. This will be done by an in depth study of two independent, structurally defined antigenic groups expressed on the surface of metastatic human melanoma cells. One antigenic group includes epitopes associated with the oligosaccharide portion of the disialogangliosides GD2 and GD3. The other antigenic group includes epitopes associated with glycoprotein receptors capable of recognizing individual components within the extracellular matrix by direct recognition of the sequence Arg-Gly-Asp (RGD) known to specify the cell binding domain of the extracellular matrix proteins fibronectin, vitronectin, collagen, von Willebrand factor and fibrinogen. It is anticipated that the approaches delineated here will eventually provide a more basic understanding of tumor invasion and metastasis in human melanoma that may ultimately lead to the development of new approaches for the treatment of metastatic disease.
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0.913 |
1999 — 2008 |
Cheresh, David A |
R37Activity Code Description: To provide long-term grant support to investigators whose research competence and productivity are distinctly superior and who are highly likely to continue to perform in an outstanding manner. Investigators may not apply for a MERIT award. Program staff and/or members of the cognizant National Advisory Council/Board will identify candidates for the MERIT award during the course of review of competing research grant applications prepared and submitted in accordance with regular PHS requirements. |
Alphav Integrins and Tumor Angiogenesis @ University of California San Diego |
1 |
2000 |
Cheresh, David A |
R13Activity Code Description: To support recipient sponsored and directed international, national or regional meetings, conferences and workshops. |
Vascular Cell Biology Conference @ Gordon Research Conferences
DESCRIPTION: During the past several years, our knowledge of the vascular system has been dramatically increased as has our ability to manipulate genetic material and cell behavior. Several aspects of vascular cell biology have undergone substantial growth and development and, in a parallel fashion, several new technologies and methodologies have been applied to the study of vascular biology. Our knowledge, in vascular biology has provided insight into mechanisms associated with embryonic development, angiogenesis, and vascular remodeling during injury. Therefore, knowledge gained in this field will have a strong impact on diseases such as cancer, arthritis, retinopathies and thrombotic disorders leading to myocardial infarction and stroke. This application is a request for funds to partially support an interdisciplinary, international conference on Vascular Cell Biology that will serve to bring together investigators, post-doctoral fellows, and graduate students from diverse fields of study for five days of intense discussion and study. This conference will be the seventh Gordon Conference on Vascular Cell Biology and is to be held at Plymouth State College on July 2-July 7, 2000. The focus of this conference will be on the mechanisms used by vascular cells to interact with their local environments and mechanisms used by vascular cells to modulate their growth. The conference will be a major vehicle for integration of new knowledge in the field and will lead to better understanding of the cell and molecular biology of the vessel wall. The planned sessions and their tentative chairs are as follows: Vascular Biology & Vessel Patterning: Dr. P. Davies (Univ. of Pennsylvania); Vascular Development: Dr. C Little (Medical Univ. of South Carolina); Cell Interactions & Neovessel Formation: Dr. D. Wagner (Harvard); ECM & Angiogenesis Vascular Bed: Dr. L. Iruela-Arispe (UCLA); Smooth Muscle Cell Biology: Dr. G. Owens (Univ. of Virginia); Signaling: Dr. M. Schwartz (Scripps); Vascular Biology & Disease: Dr. L. Parise (Univ. of North Carolina); Therapeutic Strategies: Dr. J. Isner (Tufts).
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0.909 |
2001 |
Cheresh, David A |
R13Activity Code Description: To support recipient sponsored and directed international, national or regional meetings, conferences and workshops. |
Angiogenesis and Mircrocirculation Conference @ Gordon Research Conferences
During the past several years, our knowledge of angiogenesis and microcirculation has been dramatically increased, as has our ability to manipulate genetic material and cell behavior. Several aspects of angiogenesis have undergone substantial growth and development and, in a parallel fashion, several new technologies and methodologies have been applied to the study of endothelial cells, pericytes and smooth muscle cells. Our knowledge in this area has provided insight into mechanisms associated with embryonic development, cancer, and vascular remodeling during injury or inflammatory disease. Therefore, knowledge gained in this field will have a strong impact on diseases such as cancer, arthritis, retinopathies and thrombotic disorders leading to myocardial infarction and stroke. This application is a request for funds to partially support an interdisciplinary, international conference on angiogenesis and microcirculation which will serve to bring together investigators, post- doctoral fellows, and graduate students from diverse fields of study for five days of intense discussion and study. This conference will be held at Salve Regina University on August 12-August 17, 2001. The focus of this conference will be on the mechanisms used by vascular cells to interact with their local environments and mechanisms used by vascular cells to modulate their growth. The conference will be a major vehicle for integration of new knowledge in the field and will lead to better understanding of the cell and molecular biology of angiogenesis and microcirculation. The planned sessions and their tentative chairs are as follows: Development and Remodeling: Dr. K. Alitalo(University of Helsinki), Dr. P. Carmeliet (University of Leuven), Molecular & Biochemical Regulation of Angiogenesis: L. Iruela-Arispe (University of California, Los Angeles), ECM & Adhesion: M. Friedlander (The Scripps Research Institute), Vascular Signaling: T. Hla (University of Connecticut), Blood Vessel Biology: H. Dvorak (Harvard Medical School), Angiogenesis & Cancer: A. Chambers (University of Western Ontario), New Therapeutic Strategies: M. Bednarski (Stanford University)
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0.909 |
2005 — 2009 |
Cheresh, David A |
P01Activity Code Description: For the support of a broadly based, multidisciplinary, often long-term research program which has a specific major objective or a basic theme. A program project generally involves the organized efforts of relatively large groups, members of which are conducting research projects designed to elucidate the various aspects or components of this objective. Each research project is usually under the leadership of an established investigator. The grant can provide support for certain basic resources used by these groups in the program, including clinical components, the sharing of which facilitates the total research effort. A program project is directed toward a range of problems having a central research focus, in contrast to the usually narrower thrust of the traditional research project. Each project supported through this mechanism should contribute or be directly related to the common theme of the total research effort. These scientifically meritorious projects should demonstrate an essential element of unity and interdependence, i.e., a system of research activities and projects directed toward a well-defined research program goal. |
Nanoparticle Targeting to Tumor Blood Vessels @ Sidney Kimmel Cancer Center
Anti-angiogenic approaches to treat tumors have-shown great promise in experimental animal models. However, to date it is unclear whether such therapeutic approaches will be successful in man. Efforts to improve anti-angiogenic tumor therapy have focused on vascular targeting strategies. Two of the project leaders, Drs. Schnitzer and Ruoshlati, in this program have been pioneers in the identification of vascular targets. One such target is the integrin alpha-v-beta3, which is expressed on angiogenic but not on normal blood vessels. Accordingly, we developed a non-viral gene delivery strategy that selectively targets integrin alpha-v-beta3 on angiogenic tumor-associated blood vessels in mice. Delivery of a mutant form of Raf-1 kinase to these blood vessels caused extensive apoptosis of tumor vessels which lead to the subsequent apoptosis and necrosis of the tumor itself. In this proposal we will extend our studies on targeted gene delivery to the tumor vascular in three new directions. First, as a means to test the physiological relevance of this approach, we will extend this targeted gene delivery to establish its capacity to influence the growth and metastasis of a spontaneous tumor in mice. We also will chemically conjugate the F3 peptide (Ruoslahti) and Annexin 1 antibody (Schnitzer) to a small molecule Raf inhibitor for targeted delivery to the tumor vascular. This Raf inhibitor given systemically has shown some efficacy in cancer patients. We will test the hypothesis that this agent, when targeted to tumor vessels, will produce a more robust anti-tumor response. Second, in conjunction with Dr. Dieseroff, we will test the hypothesis chemotherapeutic treatment of the tumor can synergize with our approach to target genes to the tumor vasculature. In addition, we will evaluate the role that Raf-1 plays in endothelial cell and tumor cell survival by delivery of point mutants of Raf that suppress two separate sites within its activation domain. Finally, we will also evaluate the mechanism by which alpha-v-beta3-targeted nanoparticles become endocytosed and utilize additional targeted ligands identified by Drs. Ruoshlati and Schnitzer as a means to target new genes to the tumor vasculature. These studies should provide a basis to proceed toward the clinical development of a targeted gene delivery approach to suppress the growth of tumor-associated blood vessels.
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1 |
2005 — 2009 |
Cheresh, David A |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Endothelial Barrier Function Regulation by Vegf @ University of California San Diego
DESCRIPTION (provided by applicant): This is a revised application to study the effects of vascular endothelial growth factor (VEGF) in vascular permeability and disease. VEGF induces angiogenesis and is produced in response to hypoxia during ischemic disease and cancer, yet is unique among angiogenic growth factors since it promotes vascular permeability (VP). Recent clinical studies demonstrate that an antibody against VEGF has anti-tumor activity leading to the approval of the first anti-angiogenic drug for cancer patients. While it is believed that the clinical effects of anti-VEGF are based on its anti-angiogenic activity, this has not been established. In preliminary studies, we have developed evidence for an alternative mechanism that may account for some of the anti-VEGF effects in cancer patients. In a recent study, we were able to link the VP promoting effects of VEGF to the ability of tumor cells to form pulmonary and hepatic metastatic lesions in mice. Mechanistically, this process depends, in part, on endothelial cell Src family kinases, since mice deficient in pp60Src or pp62Yes which lack a VEGF-mediated VP response are resistant to metastatic disease. We propose that in the presence of VEGF, Src-deficient mice are unable to regulate the endothelial junctional protein VE-cadherin. To this end, we determined that VE-cadherin, from WT but not Src deficient mice, was phosphorylated in response to VEGF. Our studies suggested that Src-dependent phosphorylation of VE-cadherin caused it to lose adhesive function and dissociate from the cytosolic proteins B-catenin and p120. In this proposal, we will evaluate the molecular pathway involving VEGF regulation of the endothelial cell barrier both in vitro and in vivo. In Aims 1 and 2 we will address this at the molecular level by characterizing how VEGF-mediated signaling activates Src and how Src activity regulates VE-cadherin function. In Aim 3 we will apply this knowledge to study how VEGF regulation of endothelial barrier function impacts tumor cell extravasation and metastasis. These studies not only offer new insight into the role that VEGF and Src play in vascular biology and cancer but suggest a new therapeutic strategy to block VEGF-mediated vascular permeability as a means to regulate metastatic disease.
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1 |
2007 — 2008 |
Cheresh, David A |
R21Activity Code Description: To encourage the development of new research activities in categorical program areas. (Support generally is restricted in level of support and in time.) |
Identification of Novel Pancreatic Cancer Biomarkers @ University of California San Diego
[unreadable] DESCRIPTION (provided by applicant): Pancreatic ductal adenocarcinoma is among the most lethal malignancies. Early detection is vital for patients to receive potentially curative surgery, but pancreatic cancer is often asymptomatic at the earliest most curable stages. Thus, the identification of new predictive tumor biomarkers is essential to permit the detection of early-stage pancreatic cancer. We will identify novel biomarkers of pancreatic carcinoma using a two stage approach. First, we will identify proteomic changes in the circulation of a spontaneous mouse model that replicates human pancreatic cancer genetics and disease. Mice, genetically predisposed to pancreatic cancer, will be metabolically labeled in vivo to allow quantitative analysis of the plasma proteome. Serial plasma samples collected before and during tumor development will be analyzed by Multidimensional Protein Identification Technology (MudPIT) to identify proteins that are elevated during the onset and/or progression of disease. MudPIT is a quantitative and highly sensitive proteomics platform that facilitates the discovery of differentially expressed proteins in complex samples. Biostatistical analysis of the MudPIT data will identify markers that display a significant change in circulating levels during disease progression in the mouse. To identify predictive markers of human disease, plasma from patients will be assayed by multiple reaction monitoring (MRM) for the presence of the statistically relevant mouse markers. MRM is a mass spectrometry (MS)-based approach that allows the simultaneous quantitation of multiple target analytes in samples such as plasma. In a second approach we will directly identify pathology-associated biomarkers in murine and human tumor biopsies using a novel activity-based proteomics method. This approach will identify enzymatic activities that show statistically meaningful changes as a function of tumor progression. We will validate the physiological role of enzymatic activities that change concomitant with disease progression through genetic modulation in a fluorescence orthotopic mouse model of pancreatic cancer. Identification of novel tumor-associated biomarkers may enable detection of pancreatic cancer at the earliest stages and facilitate the development of novel therapeutic strategies for this lethal disease. Pancreatic cancer often develops without obvious symptoms and since an accurate & specific screening test does not exist, diagnosis is frequently made too late for surgery to be an option. Using two state-of-the-art analytical methods, we will examine blood samples and tumor biopsies to identify markers that indicate the presence of pancreatic cancer at the earliest stages. These studies could result in a blood-based screening test for early detection of pancreatic cancer, as well as novel therapeutic strategies that could profoundly influence disease outcome. [unreadable] [unreadable] [unreadable]
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1 |
2007 — 2011 |
Cheresh, David A |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Regulation of Cell Invasion by Apoptotic Mechanisms @ University of California San Diego
[unreadable] DESCRIPTION (provided by applicant): In this revised renewal application, we propose to investigate how cell survival mechanisms contribute to the invasive properties of endothelial cells (ECs) and tumor cells during angiogenesis and metastasis, respectively. In the previous funding cycle, we showed that bFGF and VEGF suppress apoptosis of angiogenic ECs induced by intrinsic and extrinsic death pathways, respectively. These growth factors differed in their pro-survival functions based on their ability to differentially activate Raf-1 kinase. In recent studies, we have identified apoptosis signal regulating kinase 1 (ASK1) as a target of pro-survival signaling by bFGF, but not VEGF, in ECs. In Aim 1 of this proposal, we outline studies to characterize the mechanism by which Raf-1/ASK1 interact and how this interaction regulates the pro-apoptotic activity of ASK1, thereby facilitating EC invasion during angiogenesis and resistance to anti-angiogenic chemotherapeutics. The role of ASK1 in regulation of EC survival during angiogenesis and chemoresistance of tumor-associated vasculature will be examined using ASK1 knockout animals that we have recently obtained. Elevated EGFR and Src kinase activities among invasive tumor cells has been shown to promote anchorage-independent growth and survival. We have shown that Src activity leading to Raf-1 phosphorylation within its activation domain on tyrosines 340/341 promotes cellular protection from death receptor-mediated apoptosis. Thus, in Aim 2 we will test the hypothesis that the EGFR/Src/Raf signaling module and its ability to promote cell survival is critical for metastasis of invasive carcinoma cells. We contend that suppression of this survival pathway will interfere with metastatic disease within tissue microenvironments where otherwise death receptor-mediated apoptosis is limiting. Finally, in Aim 3 we propose to establish how the extracellular matrix (ECM) influences the metastatic properties of invasive tumor cells. During the previous cycle, we identified a novel apoptotic process termed integrin-mediated death (IMD) in which caspase 8 recruitment to unligated integrins on inappropriately placed cells leads to apoptosis. We recently determined that loss of IMD by suppression of caspase 8 expression was sufficient to promote invasion and metastasis in vivo. Therefore, we will establish how caspase 8 becomes activated during IMD and test the hypothesis that rescue of caspase 8 in metastatic tumor cells renders them non-metastatic. The studies outlined in this proposal will established a molecular basis to support our hypothesis that invasive cell behavior depends on the ability of cells to suppress one or more of the above mentioned apoptotic pathways. These studies may reveal new therapeutic strategies to regulate angiogenesis or the invasive properties of cancer cells. [unreadable] [unreadable] [unreadable]
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1 |
2007 — 2011 |
Cheresh, David A |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Regulation of Metastasis by Alpha V Integrin and Src @ University of California San Diego
DESCRIPTION (provided by applicant): Integrins and growth factor receptors function in a cooperative manner to regulate cellular behavior. During the previous funding cycle, we have begun to explore a signaling module in pancreatic carcinoma cells that appears to regulate the metastatic properties of these cells. We found that epidermal growth factor receptor (EGFR) together with the integrin avb5 promotes Src kinase signaling that appears to directly regulate the invasive properties of both human and murine pancreatic tumor cells. We have identified two pathways of tumor cell migration in vitro that can be distinguished by their differential dependence on Src kinase activity. Cell migration on fibronectin, collagen, and laminin mediated by b1 integrins is independent of Src, while migration on vitronectin mediated by integrin avb5 depends on Src. In Preliminary Results, we show that the EGFR/Src/avb5 signaling module initiates a cascade leading to tumor cell invasion in both orthotopic and spontaneous pancreatic cancer cell metastasis models in vivo. We have selected matched primary and metastatic pancreatic cell lines, and found that activation or overexpression of EGFR together with ligation of integrin avb5 appears to induce Src activity and downstream signaling leading to increased invasive behavior of these cells. We find that pancreatic cancer cells expressing increased Src kinase activity invade from the primary tumor deep into the host stroma while primary tumors with minimal Src activity remain confined within the tumor parenchyma as measured by intravital multi-photon imaging. In this proposal, we will characterize the mechanism by which EGFR/Src/avb5 signaling promotes invasion and metastasis. We will explore how Src tyrosine phosphorylation of specific substrates influences this invasive behavior. These studies will focus on how Src not only activates the cell migration machinery, but how it promotes the uncoupling of tumor cell adherens junctions. Finally we will explore how pharmacological and/or genetic disruption of this EGFR/avb5/Src signaling module on metastatic pancreatic cancer cells reverses their metastatic phenotype in vivo. In this case, we will evaluate the possible therapeutic relevance of these targets in orthotopic pancreatic cancer models, as well as a genetic model of spontaneous primary and metastatic pancreatic cancer. These studies should provide molecular insight into a signaling cascade that appears to contribute to the invasive behavior of pancreatic carcinoma.
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1 |
2008 — 2012 |
Cheresh, David A |
P01Activity Code Description: For the support of a broadly based, multidisciplinary, often long-term research program which has a specific major objective or a basic theme. A program project generally involves the organized efforts of relatively large groups, members of which are conducting research projects designed to elucidate the various aspects or components of this objective. Each research project is usually under the leadership of an established investigator. The grant can provide support for certain basic resources used by these groups in the program, including clinical components, the sharing of which facilitates the total research effort. A program project is directed toward a range of problems having a central research focus, in contrast to the usually narrower thrust of the traditional research project. Each project supported through this mechanism should contribute or be directly related to the common theme of the total research effort. These scientifically meritorious projects should demonstrate an essential element of unity and interdependence, i.e., a system of research activities and projects directed toward a well-defined research program goal. |
Role of Intergrin Signaling in Vascular Remodeling @ University of California San Diego
During ischemic disease, endothelial cells lining the blood vessels respond to a variety of stimuli, prompting them to undergo remodeling leading to vascular permeability and angiogenesis. In this Project, we will focus on how integrins, growth factor receptors, tyrosine kinases, and other cell adhesion molecules function in a cooperative manner to influence endothelial cell behavior during ischemic disease. Vascular endothelial growth factor (VEGF) becomes highly expressed during ischemic disease and induces both vascular leak and angiogenesis, processes which require signaling through VEGF Receptor 2 (VEGFR2). We have previously established that VEGF-induced vascular leak requires integrin av|35 and Src family kinases, leading to the disruption of VE-cadherin-mediated cell-cell adhesion. However, the interrelationships and cooperation between these key players,remain poorly understood. In this proposal, we plan to first characterize how integrin ligation influences endothelial cell barrier disruption induced by VEGF during ischemic disease. Next, we will examine how basement membrane proteins exposed during VEGF-induced vascular leak attract and activate platelets, leading to deleterious microthrombi. Lastly, we will determine how semaphorin-SA, thought to influence vascular patterning by suppressing integrin activation, promotes vascular leak in the absence of VEGF, and acts as a negative regulator of VEGF-induced angiogenesis. Together, these studies will serve to provide molecular insight into how integrin signaling mediates the vascular events initated by VEGF. Vascular leak and angiogenesis represent significant vascular remodeling events which have a profound impact on ischemic disease and inflammation. The proposed experiments will provide a better understanding of the signaling pathways in platelets and endothelial cells involved in these complex pathophysiological events, and will serve to identify new therapeutic targets to regulate VEGF-induced vascular leak and vascular remodeling following ischemic injury.
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1 |
2009 — 2013 |
Cheresh, David A |
R37Activity Code Description: To provide long-term grant support to investigators whose research competence and productivity are distinctly superior and who are highly likely to continue to perform in an outstanding manner. Investigators may not apply for a MERIT award. Program staff and/or members of the cognizant National Advisory Council/Board will identify candidates for the MERIT award during the course of review of competing research grant applications prepared and submitted in accordance with regular PHS requirements. |
Vegf and Pdgf in Angiogenesis and Tumor Progression @ University of California San Diego
DESCRIPTION (provided by applicant): Angiogenesis, the growth of new blood vessels from pre-existing vessels, contributes significantly to cancer progression and metastasis, as the angiogenic switch represents a fundamental step in the progression of a solid tumor to a faster growing and more malignant state. Unlike normal vessels, tumor-associated blood vessels are notoriously leaky and tortuous, contributing to their poor function. Accordingly, recent attempts to normalize tumor blood vessels have proven successful as a means for improved delivery of anti-cancer agents. We hypothesize, that by normalizing the tumor vasculature, it should be possible to reduce tumor cell metastasis by limiting tumor intravasation. During tumor angiogenesis, vascular endothelial growth factor (VEGF) and other angiogenic growth factors stimulate endothelial cells to sprout and form new vessels. Simultaneously, vascular smooth muscle cells stimulated by platelet-derived growth factor-BB (PDGF-BB) and its receptor PDGFR2 are recruited to tumor associated vascular sprouts facilitating vessel maturation. We have recently made the observation that the presence of VEGF can block PDGF-dependent regulation of neovascularization and vessel normalization. Thus, by blocking VEGF or the VEGF receptor 2 we can induce increase tumor vessel maturation. It is our hypothesis that VEGF, through its capacity to negatively regulate PDGFR2 function on pericytes, not only has a profound influence on neovascularization and growth of primary tumors, but also significantly impacts tumor cell intravasation, an initial step in the metastatic cascade. A major goal of our proposed studies will be to characterize the composition of the PDGFR2/VEGFR2 complex on tumor vessel associated pericytes and investigate how it regulates the cell migration and proliferation in vitro (Aim 1). We will carefully examine the mechanism by which VEGF suppresses PDGF function impacting blood vessel integrity and pericyte coverage in real time during angiogenesis in mice (Aim 2). Finally, we will determine how differential expression of VEGF/PDGF by tumor cells determines vascular maturation and angiogenesis, and assess how regulation of VEGF expression impacts the progression and metastatic properties of orthotopic and spontaneous pancreatic cancer in mice (Aim 3). Based on these studies we propose a novel therapeutic strategy to control tumor progression and metastasis. PUBLIC HEALTH RELEVANCE: Angiogenesis is the process by which new blood vessels are formed by sprouting from the existing vasculature. We have identified a surprising balance between pro-angiogenic factors which results in the blockade of angiogenesis. A thorough understanding of this system is required for the design of new therapies to manipulate the angiogenic response in order to limit tumor growth, facilitate efficient drug delivery, and ultimately improve outcome for patients suffering from metastatic disease.
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1 |
2011 — 2015 |
Cheresh, David A |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Microrna Regulation of Rasgap's During Angiogenesis @ University of California San Diego
DESCRIPTION (provided by applicant): Angiogenesis is the process by which existing blood vessels sprout to form new vessels. During development and some physiological events in the adult, angiogenesis occurs as a controlled series of events leading to vascular remodeling that supports changing tissue requirements. A host of pro- and anti-angiogenic factors work in a balance to allow initial sprouting and invasion, subsequent pruning and remodeling, and finally maturation and survival. However, in pathological situations such as cancer, the same angiogenic signaling pathways are induced and exploited, typically resulting in poorly organized vessels with leaky and tortuous properties. Angiogenesis is ultimately controlled by a balance of pro- and anti-angiogenic factors that regulate the recruitment and activation of stromal and vascular cells. Here, we have identified a novel pathway in which a pro-angiogenic microRNA disrupts the expression of an anti-angiogenic signaling molecule. MicroRNAs are short nucleotide sequences that have the ability to block expression of target genes. We have identified miR-132 as a microRNA which is not expressed in stable quiescent vessels, but which is upregulated in angiogenic tissues and in endothelial cells stimulated with growth factors. Expression of miR-132 is sufficient to drive vascular sprouting and proliferation in the absence of growth factors, whereas inhibition of miR-132 blocks growth factor-induced angiogenesis. Thus, we have shown that miR-132 functions as a pro-angiogenic factor which can activate endothelial cells. Furthermore, we have identified a RasGAP family member, p120RasGAP, as a primary target gene of miR-132. In Aim 1, we will evaluate the contribution of p120RasGAP activity to Ras-dependent and Ras-independent signaling, and determine whether the expression of p120RasGAP may be modulated by additional miRs during angiogenesis. In Aim 2, we will characterize the expression and role of RasGAP homologs in endothelial cells, and identify whether these may also be subject to miR regulation during angiogenesis. The long-term objective and clinical application of this work is to evaluate the use of anti-miRs targeting RasGAP family members as anti-angiogenic therapies for diseases that are exacerbated by vascular proliferation (Aim 3). Together, these studies will provide insight into the role of RasGAPs during angiogenesis and establish a molecular basis to support the development of anti-miR therapy as an anti-angiogenic strategy for patients with vascular proliferative disease.
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1 |
2012 — 2016 |
Cheresh, David A |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Targeting a Non-Canonical Ras-Driven Pathway in Pancreatic Cancer @ University of California San Diego
Project Summary/Abstract Activating K-RAS mutations occur in >95% of patients with advanced pancreatic cancer, and recent studies identify CRAF as a kinase required for tumorigenesis downstream of oncogenic K-RAS. Although CRAF kinase activity is traditionally linked to tumor progression via activation of MAPK signaling, we have focused our attention on two non-canonical CRAF pathways which are independent of CRAF catalytic activity and activation of MAPK. Several years ago, we established that CRAF phosphorylation on serine 338 (pS338) drives CRAF translocation to the mitochondria where it forms a complex with and inactivates the pro-apoptotic kinase ASK1 to promote cell survival. In a new manuscript in press at Nature Medicine, we now report that CRAF pS338 also forms a complex with the cell cycle kinase Plk1 at the mitotic spindle to impact cell cycle progression. Accordingly, genetic or allosteric inhibition of this serine on CRAF drives both apoptosis and mitotic arrest that is independent of the MAPK pathway and not observed with inhibitors of MAPK signaling. Our overall objective is therefore to target CRAF function and exploit its role in both cell survival and mitotic progression, in order to develop novel therapeutic approaches for pancreatic cancer patients. The proposed studies will define how these two unique MAPK-independent functions of CRAF contribute to progression and metastasis of pancreatic cancer driven by oncogenic K-RAS. In Aim 1 we determine the mechanisms by which the non-canonical CRAF pS338 pathway is activated in the unique genetic context of pancreatic cancer. Specifically, we will focus on how both K-RAS and PAK regulate CRAF pS338, since these molecules are known to be dysregulated in pancreatic cancer. The goal of Aim 2 is to evaluate the contributions of the two non-canonical CRAF pS338 pathways on pancreatic cancer cell survival (via ASK1) and cell proliferation (via Plk1) as these relate to tumor growth and metastasis of pancreatic cancer in vivo. Since mitosis is the most radiosensitive stage of the cell cycle, the goal of Aim 3 is to use mouse models of pancreatic cancer and metastasis to understand how to optimally combine ionizing radiation with blockade of this novel CRAF pS338 pathway which induces mitotic arrest. We anticipate that our innovative approach to target tumor cell survival, proliferation, and radiosensitivity via the K-RAS/CRAF pathway will lead to exciting new opportunities for metastatic pancreatic cancer.
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1 |
2013 — 2017 |
Cheresh, David A |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Integrin Alpha V Beta 3 Promotes Resistance to Egf Receptor Inhibitors @ University of California San Diego
DESCRIPTION (provided by applicant): Integrin ?v?3 is expressed in the most aggressive and metastatic cancers. Here, new experimental data suggests that ?v?3 also drives a novel pathway of resistance to EGFR-targeted therapies. In fact, different epithelial carcinoma cell lines exposed to the EGFR inhibitors erlotinib or lapatinib for several weeks show enhanced expression of the integrin ?3 subunit in the subpopulation of surviving cells. Mechanistically, ?v?3 integrin promotes the plasma membrane clustering of oncogenic K-Ras to drive its signaling to RalB and its downstream effectors. This ?v?3/K-Ras/RalB oncogenic unit not only increases anchorage-independence in vitro and tumor growth in vivo, but it also renders tumors resistant to EGFR inhibition. These findings suggest that disabling components of this novel pathway may enhance the sensitivity to EGFR-targeted therapies. Experiments outlined in this proposal will examine the significance of the ?v?3/K-Ras interaction in terms of EGFR inhibitor resistance for a number of epithelial cancers in vitro and in vivo. The goal of Aim 1 is o define the structural basis for the association between integrin ?v?3 and K-Ras, which appears to drive RalB- mediated signaling in epithelial carcinoma cells. Studies in Aim 2 are designed to determine which ?3/K- Ras/RalB effectors drive anchorage-independence and erlotinib resistance, and to test both genetic and pharmacological strategies to block this pathway in vitro. Finally, Aim 3 will evaluate strategies to overcome EGFR inhibitor resistance for subcutaneous and orthotopic mouse cancer models. If successful, these studies will support the continued use of EGFR-targeted therapies in the clinic, and offer novel strategies to improve response to such therapies once tumors acquire resistance.
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1 |
2015 — 2018 |
Cheresh, David A |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Craf-Mediated Vascular Resistance to Cancer Therapies @ University of California San Diego
DESCRIPTION (provided by applicant): Our proposal is focused on how CRAF signaling in vascular cells promotes endothelial cell survival and resistance to different forms of cellular stresses present within the tumor microenvironment. In addition to activating the kinase-dependent RAS-RAF-MEK-ERK pathway, CRAF phosphorylation on Serine 338 (pS338) represents an additional target that could be suppressed to improve the effects of cancer therapy on tumor blood vessels. Mechanistically, we established that CRAF pS338 functions as a molecular scaffold to recruit effectors that drive a variety of signaling pathways, such as the cell cycle kinase PLK1 and the DNA repair enzyme CHK2. Activation of these pathways can be blocked by expressing a non-phosphorylatable CRAF S338A mutant or by treatment with 3G8, an allosteric inhibitor we developed that not only blocks the kinase-dependent activation of MEK/ERK, but also holds CRAF in an inactive conformation to suppress pS338. Based on these studies, we propose that a CRAF interactome represents a significant factor in endothelial cell resistance to genotoxic stress. In addition to PLK1 and CHK2, computational modeling was used to identify additional kinases predicted to couple with and be activated by the kinase-dead form of CRAF, and a mass spectrometry screen was performed to identify proteins that favor association with CRAF when phosphorylated on S338. In the following Specific Aims, we will test the hypothesis that disabling CRAF's ability to couple with and activate these effectors will enhance the damaging effects of stress and sensitize tumor-associated blood vessels to therapy. Aim 1: Evaluate functions of kinase-dead CRAF as a scaffold and kinase activator in EC Aim 2: Test the ability of RAF blockade to potentiate activity of cell cycle inhibitors, DNA damaging agents, and anti-angiogenics Aim 3: Target non-canonical CRAF functions to disrupt tumor angiogenesis in vivo If successful, our studies should generate broad interest. From a clinical perspective, strategies to target CRAF pS338 could graduate to clinical testing for a broad population of cancer patients with the possibility of enhancing anti-tumor activity and lowering the chemo/radiation dose required for efficacy. At the basic science level, we believe we have identified a new kinase-independent function for a kinase, and that what we learn about this new scaffolding function of CRAF could be applied to other kinases.
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2019 — 2021 |
Cheresh, David A |
R35Activity Code Description: To provide long term support to an experienced investigator with an outstanding record of research productivity. This support is intended to encourage investigators to embark on long-term projects of unusual potential. |
Attacking Stress Tolerance in Cancer @ University of California, San Diego
Project Summary/Abstract My career began with the identification of cell surface markers on invasive cells, and led to the discovery of how integrins ?v?3 and ?v?5 on endothelial cells respond to cues within the tumor microenvironment to promote angiogenesis. I later demonstrated that ?V integrins on tumor cells use these same fundamental pathways to achieve aggressive, invasive, and metastatic behavior. Now, my R35 proposal represents a further evolution of these concepts to ask how tumor cells undergo reprogramming in response to cellular stresses, including hypoxia, nutrient deprivation, or cancer therapy. We find that ?v?3 expression can be induced by stress to reprogram tumor cells toward a stress-tolerant, drug-resistant, stem-like state that is associated with tumor progression and metastasis for a wide range of cancers. Because individual tumors use this integrin to overcome unique challenges, we will define how ?v?3 activates downstream effectors that vary between tumor type, genetic profile, and microenvironment. The overall goal of my future research program is to understand how such tumors use integrin ?v?3 to gain stress tolerance so that we can devise ways to attack this process therapeutically. This proposed research will not only lead to a fundamental understanding of how tumors adapt to therapy or microenvironmental stress, but it should identify new druggable targets to limit cancer progression by preventing or overcoming tumor cell drug resistance and stress tolerance.
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2019 — 2021 |
Cheresh, David A Onaitis, Mark |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Exploiting Kras Addiction For Lung Cancer Therapy @ University of California, San Diego
Project Summary/Abstract Exploiting KRAS addiction for lung cancer therapy There is a great unmet need to develop new approaches for KRAS mutant lung cancers. While 25-30% of lung adenocarcinomas arise by virtue of activating KRAS mutations, individual tumors may develop KRAS indifference over the course of cancer progression. It is well-appreciated that cancer cells continue to develop adaptations to support the uncontrolled growth and survival required for tumor progression and metastasis. New data shows that the expression of integrin ?v?3 on KRAS mutant cancer cells predicts which tumors remain dependent on KRAS for tumor growth as well as anchorage-independent growth, a hallmark of cancer that is required for invasion and metastatic spread. While a variety of membrane receptors function by clustering in adherent cells, integrin ?v?3 is unique in its ability to cluster and drive signaling pathways in the absence of extracellular matrix anchoring. The Preliminary Results establish that integrin ?v?3 clustering in non-adherent cells gives rise to KRAS addiction by enabling multiple functions of KRAS that drive stress tolerance, including formation of macropinosomes that facilitate nutrient uptake and promotion of a gene expression program that favors redox balance. The overall goals of this proposal are to define how ?v?3-mediated KRAS clustering promotes survival advantages that drive KRAS addiction and contribute to lung cancer initiation, progression, and metastasis in vivo. Understanding the molecular mechanisms critical for this pathway will foster the design of new therapies to exploit the unique vulnerabilities of KRAS mutant cancers. The Specific Aims of this Multi-PI R01 are designed to understand the cell and molecular biological role for ?v?3 as a regulator of KRAS addiction (Aim 1 ? led by Dr. Cheresh) and to learn how this relates to cancer initiation and progression using genetically-engineered mouse models of lung cancer driven by oncogenic Kras (Aim 2 ? led by Dr. Onaitis). These findings will enable the logical design of new strategies to target KRAS- addicted cells for cancer therapy (Aim 3 ? a collaborative effort). Aim 1: Establish the molecular basis for ?v?3 regulation of KRAS functions in vitro Aim 2: Define the impact of ?v?3 on Kras-driven NSCLC in vivo Aim 3: Exploit KRAS addiction to enhance cancer therapy
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