Joseph Schlessinger - US grants

DESCRIPTION (Applicant's Description) A major aspect of cellular signaling involves the identification and characterization of molecules that transmit signals from the cell surface to the nucleus in response to hormones, light, odorants and growth factors among many other extracellular signals. The recent elucidation of the three dimensional structure of several of the molecules involves in signal transduction has been particularly valuable in these efforts. In this meeting, lectures will be presented to cover various mechanisms by which signals are transmitted across the plasma membrane via the cytoplasm to the cell nucleus. Emphasis will be placed on G-protein and receptor tyrosine kinase systems. In addition, a variety of mutations that occur in signaling molecules lead to variety of disease and detailed understanding of the associated pathways and their control mechanisms should enhance the development of novel drugs and treatments. Several pathologies that have been related to cell signaling abnormalities will be discussed.

DESCRIPTION (provided by applicant): Fibroblast growth factors (FGFs) comprise a large family of growth factors that play important roles in the control of embryonic development, morphogenesis, wound healing, and tumor angiogenesis. FGFs mediate their diverse cellular responses by acting in concert with heparin sulfate proteoglycans to activate a family of receptor tyrosine kinases (RTK) designated FGF-receptors 1 to 4 (FGFR1-FGFR4). We have identified a family of docking proteins designated FGFR-substrate 2 (FRS2) that function as major mediators of signaling via FGFRs. The current application seeks to obtain a detailed view on cellular signaling through FGFRs. Our main goal is to determine the biological role and mechanism of action of FRS2 in FGFR signaling in vitro and in vivo. The specific aims of this proposal are to: 1. Identify the FRS2-dependent independent signaling pathways downstream of FGFR1 and FGFR2. 2. Identify the role of Shc in mediating FGF-signaling pathways. 3. Determine the mechanism and biological significance underlying the interaction between FRS2 and MAPK. 4. Determine the role of FRS2 in mediating heterologous control of FGFl-signaling and 5. Develop genetically modified mice to explore the biological role of FRS2 in vivo. The primary means to accomplish these aims are biochemical analysis of cultured cells expressing wild type or mutant proteins, X-ray crystallographic studies of components of FGFR signaling, in vivo studies of genetically modified mice and analysis of FGF-signaling in cells isolated from knock-in and knock-out mice. The information obtained from these studies will enhance our knowledge on intracellular signaling pathways downstream of FGFR and other RTKs. It would also provide a framework for understanding the role of FGFR-signaling in normal biological responses and in diseases caused by dysfunctions in FGFRs such as Crouzon, Apert, Jackson-Weiss syndromes and other skeletal disorders, as well as tumor angiogenesis, and cancer.

[unreadable] DESCRIPTION (provided by applicant): Fibroblast growth factors (FGFs) and their surface receptors (FGFRs) are critical components of many important biological processes including bone development. The four known FGFRs (FGFR1-FGFR4) are receptor tyrosine kinases (RTKs) activated by binding FGFs and heparin or heparan sulfate proteoglycans to their extracellular ligand binding domain resulting in FGFR dimerization and protein tyrosine kinase activation. It has been shown that the docking protein FRS2 plays a major role in mediating the intracellular signaling pathways following FGF stimulation. Other proteins implicated in FGF signaling include Shc, Gab1, Shp2 and Stat1 among others. Gene inactivation experiments in mice have shown that FGFR2 and FGFR3 play an important role in bone development. Moreover, mutations primarily in Fgfr2 and Fgfr3 were shown to be responsible for a variety of bone and skeletal disorders including Crouzon, Apert, Jackson- Weiss, achondroplasia and thanatophoric dysplasia syndromes. The goal of this proposal is to obtain a comprehensive view of the intracellular signaling pathways that are responsible for mediating bone development in response to FGFR2 and FGFR3 activation. The specific aims of this proposal are to: (1) investigate the specific roles of the Fgfr3b and Fgfr3c isoforms in bone development by creating isoform specific knock-out mice, (2) develop genetically modified mice to explore the biological role of the docking protein FRS2 in Fgfr2c mediated bone development, (3) determine the role of FRS2 in human Icraniosynostosis syndrome using murine models, (4) identify FRS2 dependent and independent signaling Ipathways downstream of FGFR2 and FGFR3, and (5) determine the role of the SH2 domain containing IProtein 3BP2 in signaling via FGFR2 and FGFR3. Mutations in 3BP2 were found in cherubism, an lautosomal dominant inherited syndrome characterized by excessive bone degradation. Our goals will be accomplished by applying genetic, biochemical, structural and cell biological approaches. The information obtained from these studies will provide a detailed molecular view of how FGF signaling mediated by FGFR2 and FGFR3 and the docking protein FRS2 control bone development. It will also provide a framework for understanding diseases caused by mutations in FGFRs enabling the design of novel treatments for skeletal disorders such as craniosynostosis, achondroplasia, hypochondroplasia and thanatophoric dysplasia. [unreadable] [unreadable]

The Signal Transduction Program (STRP) has evolved from the antecedent Breast Cancer Research Program (BCRP). This change was accomplished with recognition that signaling molecules are now the leading targets for novel cancer therapies and that these targets transcend boundaries of individual diseases like breast cancer. STRP faculty share an interest in understanding signal transduction processes for the purpose of developing novel cancer therapies. Towards this end, the STRP capitalizes on the quality of fundamental signal transduction research at Yale, and the growing translational importance of signal transduction molecules as cancer therapeutic targets. During the last project period, several receptor and non-receptor tyrosine kinases emerged as validated targets for FDA-approved drugs. Research by the STRP will identify new therapeutic targets among receptors and the pathways they regulate, and facilitate best use of these drugs through personalized medicine. The overall goal of the STRP is to foster basic research leading to rapid therapeutic development in major areas of Signal Transduction research, 1) Signal Transduction;2) Intracellular Signaling Pathways;3) Cell Polarization and the Cytoskeleton;and 4) Subcellular Protein Trafficking. These goals will be achieved through the monthly STRP meetings;through Pilot/Developmental awards that foster new approaches, hew collaborations, and translational work;through the annual retreat;through integration with the Developmental Therapeutics Program for streamlined translational development;and by cross-fertilization with other Programs of the YCC. The co-Leader, Dr. Joseph Schlessinger, has made unparalleled contributions in elucidation of growth factor receptor signal transduction, and in development of structure-based anti-cancer drugs that inhibit signal transduction molecules. Dr. David F. Stern continues as co-leader from the precursor BCRP from which the STRP developed. Dr. Stern has made important advances in understanding HER2/ErbB2 that have facilitated the rapid development of anti-HER2 drugs, and he has long been interested in rational molecular diagnostics based on principles of signal transduction. The distinguished faculty of this program of 26 members includes two members of both the National Academy of Sciences and the Institute of Medicine, several members of the American Academy of Arts &Sciences and EMBO, NIH MERIT award recipients, and the Assoc. Director for Basic Science of the YCC. Program expertise encompasses fundamental aspects of signal transduction, integrins and cortical cytoskeleton, and protein trafficking and sorting. An important goal will be the generation of novel ideas through increased communication of signal transduction biologists with cell structure/trafficking experts. In the last grant period, members of the BCRP or STRP published 365 cancerrelated papers, of which 4.4% represented intraprogrammatic collaborations, and 20.8% were interprogrammatic. (A number of joint publications are not listed since they predate YCC membership). The STRP presently has twenty-five members from nine departments, with total research funding of $11.3 million direct costs ($16.4 million total), $1.7 million direct costs ($2.8 million total) is NCI-funded and $8.0 million direct costs ($11.8 million total) is other peer-reviewed.

Identification of mutations in receptor and non-receptor protein kinases that drive malignant transformation of cancer cells ('driver' mutations) have revolutionized patient care by opening the door to patient-tailored targeted therapies that can improve patient survival. In order to discover new targets for therapy, we sequenced the coding regions of -100 melanomas and identified a large number of somatic mutations and inherited Single Nucleotide Variants (SNVs). One of the most important findings of this effort is the identification ofthe RAC1 signaling pathway as a potential new target for melanoma therapy. The analysis revealed a recurrent, UV signature activating mutation in this RHO family of small GTPases, RAC[P29S], in ~5% of melanomas, in addition, the sequencing data revealed mutations in upstream regulators and downstream effectors of RAC1 pathway in a large numbers of melanoma tumors. Functional studies demonstrated an important role in proliferation and migration of not only mutant but also melanoma cells that that donot harbor the P29S mutation. The data suggest that pharmacological inhibition of RACl or its critical effeGtor(s) can be applied for development of new therapies for melanoma patients. The general goals ofthis project are to determine the frequency and prognostic significance of RAC[P29S] mutation in sun exposed melanocytic lesions, and to identify downstream effectors of RACl most likely to be druggable targets in this pathway. The specific aims are: Aim 1: To determine the frequency of RAC1[P29S] mutation and RACl expression levels in a large cohort of melanocytic lesions and correlate with pathological features and tumor progression; Aim 2: To elucidate the downstream targets of activated RACl in melanomas. Aim 3: To identify small-molecule inhibitors of PAK kinases, the RACl effectors. These studies are likely to provide new opportunities for drug discovery for melanomas and possibly other cancers that can facilitate patienttailored targeted therapy.