Program Director/Principal Investigator (Last, First, Middle): Rankin, Gary O 74HOMER2 AS A SUPPRESSOR OF CELL INVASION AND PODOSOME FORMATION(0027)TYPE:Research Subproject%IDeA $: 5.000% IDeA $: 168,125INVESTIGATOR, DEGREEShurina, Robert PHDWeed, Scott PHDDEPARTMENTBiologyNeurobiology AndAnatomyNON-HOST INSTITUTION: STATE,COUNTRYWheeling Jesuit University, Wv UsaWest Virginia University, Wv UsaTotal # human subjects expected for entire study: 0Total # human subjects enrolled to date: 0SUBPROJECT DESCRIPTIONPodosomes are actin-rich projections <strong>of</strong> the cell membrane that are associated with cancer cell migrationand metastases. Their formation requires rearrangements <strong>of</strong> the actin cytoskeleton, which are mediatedthrough the interaction <strong>of</strong> a host <strong>of</strong> actin-binding proteins. Tumor-promoting phorbol esters cause actincytoskeletal rearrangements that result in podosome formation in a variety <strong>of</strong> cell types; including vascularsmooth muscle cells, osteoclasts, macrophages, endothelial cells, neural cells myoblasts and transformedfibroblasts. Tumor-promoting phorbol esters function by activating one or more PKC is<strong>of</strong>orms, resulting inthe reorganization <strong>of</strong> the actin cytoskeleton and src activation A<strong>FA</strong>P-110, an adaptor protein thatcross-links actin filaments, activates Src in response to phosphorylation by PKC- and is involved inpodosome formation. Increased levels <strong>of</strong> A<strong>FA</strong>P-110 are correlated with increases in podosome lifetime inA7r5 tumor cells and prostate cancer. Although the role <strong>of</strong> A<strong>FA</strong>P-110 as a Src activator is well established,the mechanism by which activated A<strong>FA</strong>P-110 is itself regulated remains incompletely characterized.Scaffolding proteins, such as Tks5, recruit A<strong>FA</strong>P-110 and other signaling proteins to podosomes. Homer2is a scaffolding protein that interacts with both actin filaments and activated Rho GTPases in mousecerebellar cells and can prevent podosome formation in cdc42-activated HeLa cells. Homer2 has beenidentified as a binding partner for A<strong>FA</strong>P-110 in two independent yeast two-hybrid studies. We hypothesizethat Homer2 is a binding partner and regulator for A<strong>FA</strong>P-110. In this proposal we will address themechanism by which Homer2 abrogates podosome formation.SUBPROJECT PROGRESSSpecific Aim #1: Identify protein binding partners that regulate A<strong>FA</strong>P-110 activity. We have shownthat Homer2 is expressed in a wide variety <strong>of</strong> human cancer cell lines, including HEK-293T cell line;the ovarian cancer CaOV3 cell line; the prostate cancer PC3 cell line; the neuroblastoma SY5Y cellline; and the epithelial cancer UMSSC-1 cell line.We have also demonstrated that Homer2 and A<strong>FA</strong>P-110 co-localize to lamellipodia in A7r5 tumorcell lines that are stimulated with phorbol myristate acetate (PMA).Other progressPresentations: Richards, T.D. and R.D. Shurina (2011). Homer2 binds A<strong>FA</strong>P-110 and localizes tothe cortical actin cytoskeleton in lamellipodia. Presented at the 10thAnnual <strong>WV</strong>-<strong>INBRE</strong> Summer Research Symposium, Huntington, <strong>WV</strong>, July 2011.Student research mentor: Eight undergraduate student researchers were supported by this award.Six <strong>of</strong> these students were awarded scholarships through the NASA-West Virginia Space GrantConsortiumNew research collaborations: Thanks to the expertise that I gained from support through the<strong>WV</strong>-<strong>INBRE</strong> research network, my lab is in the process <strong>of</strong> forming a research collaboration with Dr.Gregory Merrick at the Schiffler Cancer Center <strong>of</strong> the Wheeling Hospital (Wheeling, <strong>WV</strong>) toinvestigate whether proteins involved in the A<strong>FA</strong>P-110/Src signaling pathway can be used asprognostic indicators <strong>of</strong> prostate cancer.PHS 2590 (Rev. 06/09)Continuation Format Page
Program Director/Principal Investigator (Last, First, Middle): Rankin, Gary O 75PROTECTION AGAINST RESEARCH RISKSN 1. Will human subjects be involved next year?N 2. Will vertebrate animals be used next year?Y 3. Will recombinant DNA experiment(s) be conducted next year?If yes, provide the date <strong>of</strong> Office <strong>of</strong> Recombinant DNA Activities (ORDA), NIH approval:EXEMPTY 4. Are there potential hazards to laboratory workers (carcinogens, pathogens, ionizing radiation, etc.)involved in the proposed research for next year? If yes, identify:NCarcinogen5. Will any <strong>of</strong> the research-risk categories,not involved next year, be involved future years? If yes, identify:PHS 2590 (Rev. 06/09)Continuation Format Page
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