Gelman, Irwin H., PhD

Dr. Irwin Gelman

Vice Chairman
Department of Cancer Genetics
Roswell Park Cancer Institute
Elm and Carlton Streets
Buffalo, NY 14263
Telephone: (716) 845-7681
Fax: (716) 845-1698
E-mail: Irwin.Gelman@RoswellPark.org

General Research Interest

Role of Src and FAK family tyrosine kinases in tumor biology

Current Program

Role of the SSeCKS/Gravin/AKAP12 metastatis suppressor gene in prostate cancer
SSeCKS knockout mouse: tumor-prone model?
Focal adhesion kinase (FAK) and Pyk2 in Src-induced transformation and tumorigenesis
FAK-specific substrates and pathways in cell survival and oncogenic transformation
Identification of metastasis-specific genes in prostate cancer
Development of Src-specific small molecule inhibitors

Laboratory Personnel

Shin Akakura PhD
Yahao Bu
Lingqiu Gao
Li-Wiu Guo PhD
Renae Holtz
Adam Kisailus PhD
Peter Nochajski
Bing Su PhD

Description of Research

Currently, there are four active research programs in my laboratory:

Identification and characterization of novel mitogenic regulatory genes encoding tumor suppressive functions.
Control of cytoskeletal architecture and mitogenic signaling by Src-family kinases and the focal adhesion kinase, FAK, in normal and cancer cells.
Identification of novel metastasis-suppressor genes in a prostate cancer system.
Development of Src-specific small molecule inhibitors in preclinical studies.

1) Identification of Novel Regulatory/Tumor Suppressor Functions

A current theory for the genetic basis of cancer states that cancers arise through a combination of mutations that induce the oncogenic activity of proto-oncogenes and inhibit the control activities of tumor suppressor genes. My assumption was that genes whose expression is downregulated in cells transformed with oncogenes such as src or ras might be candidate tumor suppressor genes. I also assumed that genes involved in critical steps in mitogenic control would be expressed at low basal levels and would also be serum-responsive. Based on differential screens we developed to satisfy these criteria, my laboratory identified several new candidate control genes, one of which encodes.

SSeCKS, a new major protein kinase C substrate that also shows tumor suppressive activity. The cell-cycle expression and phosphorylation of SSeCKS, as well as its ability to interact with the actin-based cytoskeletal, suggests that SSeCKS plays a key role in controlling both mitogenic signaling and cytoskeletal architecture.

SSeCKS seems to work as a "scaffolding protein". In its underphosphorylated form (expressed in early G1 phase or in contact-inhibited cells), it binds key signaling proteins such as PKC, PKA, calmodulin and G1 phase cyclins. Phosphorylation of SSeCKS by mitogen- and integrin-activated kinases inhibits in vitro and in vivo scaffolding activity. The fact that SSeCKS expression is severely downregulated in src- and ras-transformed fibroblasts and epithelial tumors, and that the human orthologue maps to a deletion hotspot in >60% of cases of advanced prostate, breast, and ovarian cancer (6q24-25.2), strengthens the notion that SSeCKS is a tumor suppressor. Indeed, we showed that re-expression of SSeCKS using tetracycline-regulated vectors causes a reorganization of cytoskeletal architecture, leading to the suppression of src- and ras- induced oncogenic growth in vitro and the loss of metastatic potential in vivo in a rat prostate cancer model.

We are continuing to study how the loss of SSeCKS leads to metastatic behavior in human prostate cancer. We are also characterizing how SSeCKS interacts or competes with p21 and p27 during its binding to cyclin D, and how this affects the formation of kinase active (Model for SSeCKs' scafolding function) complexes of cyclin D and CDK4 in the cytoplasm. This latter control point in the cell cycle is critical as to whether cells proliferate or differentiate, and indeed, we have found several cell systems in which SSeCKS expression is induced upon differentiation. We are actively researching whether SSeCKS helps establish or maintain the differentiated state of glomerular mesangial cells, hepatic stellate cells or thrombopoietin- induced megakaryocytes.

My lab's interest in cancer genetics, specifically in identifying new mitogenic regulatory genes that are transcriptionally downregulated in transformed cells, continues. We have developed two techniques for selectively screening libraries for relevant mitogenic regulatory genes (i.e.- potential tumor suppressors), and we are actively characterizing several new gene candidates.

2) Control of cytoskeletal architecture and mitogenic signaling by Src-family kinases and the focal adhesion kinase, FAK, in normal and cancer cells

Oncogenes such as v-Src induce oncogenic transformation by altering both mitogenic and cytoskeletal signaling pathways. The latter pathways are less understood, but there is consensus that changes in the actin-based cytoskeleton and in cell-cell interactions correlate with advanced tumor behavior such as metastatic potential and invasiveness. The focal adhesion kinase, FAK, seems to function downstream of v-Src to regulate cell architecture and cytoskeletal signaling. Thus, we are actively studying how FAK contributes to the control of mitogen- and integrin-induced cytoskeletal and proliferative signaling pathways in untransformed and in Src-transformed cells. We have made use of mouse embryo fibroblasts from control and FAK knockout mice into which we transduce temperature-sensitive alleles of v-Src or minimally oncogenically-activated human Src alleles. Our data strongly suggest a novel role for FAK, that of a temporal scaffolding protein that binds multiprotein complexes including Src, PI3K and CAS via both SH2 and SH3 motifs, leading to the inhibition of protein tyrosine phosphatases (PTP) in the absence of mitogen- and integrin-mediated activation signals. Our data indicate that FAK can play either positive or negative roles in oncogenic transformation depending on temporal and spacial constraints. Inasmuch as many tumors express elevated levels of FAK, my long-term interest is to elucidate the temporal roles of FAK during normal cell cycle progression versus potential roles during oncogenesis or even control of apoptosis.

3) Identification of Novel Metastasis-Suppressor Genes

We are using human and mouse genome-wide shRNA retrovirus libraries to identify genes whose downregulation increases metastatic potential without affecting tumor growth at primary sites in prostate cancer models. Special focus is given to genes that control invasive motility, tumor angiogenesis and cytoskeletal remodeling.

4) Development of Src-specific small molecule inhibitors

In collaboration with Kinex Pharmaceuticals, LLC, our lab has helped develop novel, specific and potent inhibitors of Src-family tyrosine kinases that target the so-called peptide-binding, rather than ATP-binding domain. A third-generation compound, KXO1, inhibits Src-driven oncogenic proliferation in cell culture and tumor xenograft models at low nanomolar concentrations. We have developed a special expertise to characterize how these types of drugs can inhibit Src kinase activity in cells using phospho-specific antibody-based blots that survey a panel of tyrosine kinases and phosphatases as well as Src-specific substrates. KXO1 is currently under development for clinical trials for solid tumors and leukemias in which Src-family activity is required for primary and/or metastatic growth.

Key Publications

Bu Y and Gelman IH. v-Src-mediated downregulation of the SSeCKS metastasis suppressor gene promoter by the recruitment of HDAC1 into a USF1/Sp1/Sp3 complex. J Biol Chem 2007; 282(37):26725-26739.
Liu Y, Gao L, Gelman IH. SSeCKS/Gravin/AKAP 12 attentuates expression of proliferative and angiogenetic genes during suppression of v-SRC-induce oncogenesis. BMC Cancer Res 2006; 6:105.
Chaar Z, O'Reilly P, Gelman I, Sabourin LA. V-SRC-dependent down-regulation of the Ste20-like kinase SLK by casein kinase II. J Biol Chem 2006; 281:28193-28199.
Greenberg RS, Bernstein AM, Benezra M, Gelman IH, Taliana L, Masur SK. FAK-dependent regulation of myofibroblast differentiation. FASEB J 2006; 20:1006-1008.
Su B, Zheng Q, Vaughan MM, Bu Y, Gelman IH. SSeCKS metastasis-suppressing activity in MatLyLu prostate cancer cells correlates with vascular endothelial growth factor inhibition. Cancer Res 2006; 66:(11):5599-5607.
Gelman IH and Gao L. SSeCKS/Gravin/AKAP12 metastasis suppressor inhibits podosome formation via RhoA- and Cdc42-dependent pathways. Mol Cancer Res 2006; 4(3):151-158.
Moissoglu K, Sachdev S, Gelman IH. Enhanced v-Src induced oncogenic transformation in the absence of focal adhesion kinase in mediated by phosphatidylinositol 3 kinase. Biochem Biophys Res Commun 2005; 330:673-684.
Streb JW, Kitchen CM, Gelman IH, Miano JM. Multiple promoters direct expression of three AKAP12 isoforms distinct tissue and subcellular distribution profiles. J Biol Chem 2004; 279:53:56014-56023.
Gherardi D, D'Agati V, Chu TTH, Barnett A, Gianella-Borradori A, Gelman IH, Nelson PJ. Reversal of collapsing glomerulopathy in mice with the cyclin-dependent kinase inhibitor CYC202. J Am Soc Nephrol 2004; 15:1212-1222.
Moissoglu K, Gelman IH. v-Src rescues actin-based cytoskeletal architecture and cell motility, and induces enhanced anchorage-independence during oncogenic transformation of focal adhesion kinase-null fibroblasts. J Biol Chem 2003; 278:47946-47959.
Nelson P, D'Agati V, Gries J, Suarez J, Gelman I. Amelioration ofnephropathy in mice expressing HIV-1 genes by the cyclin-dependent kinase inhibitor flavopiridol. J Antimicrob Chemother 2003; 51:921-929.
Gelman IH: Pyk 2 FAKs, any two FAKs. Cell Biol Int 2003; 27:507-510.
Gelman IH: Isolation of novel substrates using a tyrosine kinase overlay/in situ assay. Methods Mol Biol 2003; 218:133-141.
Lee S-W, Kim WJ, Choi YK, Song HS, Son MJ, Gelman IH, Kim Y-J, Kim K-W. SSeCKS regulates angiogensis and tight junction formation in blood-brain barrier. Nat Med 2003; 9:900-906.
Gelman IH. The role of SSeCKS/Gravin/AKAP12 scaffolding proteins in the spaciotemporal control of signaling pathways in oncogenesis and development. Front Biosci 2002; 7:1782-1797.
Nelson PJ, Sunamoto M, Husain, M, Gelman IH. HIV-1 expression induces cyclin D1 expression and activity in infected podocytes: a mechanism for the proliferative phenotype in HIV-associated nephropathy. BioMed Central Microbiol 2002; 2:26-36.
Xia W, Gelman IH. Mitogen- and FAK-regulated tyrosine phosphorylation of the SSeCKS scaffolding protein modulates its actin-binding properties. Exp Cell Res 2002; 277(2):139-151.
Cara A, Vargas J Jr. Keller A, Jones S, Mosoian A, Gurtman A, Cohen A, Parkas A, Wallach F, Chusid E, Gelman IH, Klotman ME. Circular viral DNA and anomalous junction sequence in PBMC of HIV-infected individuals with no detectable plasma viral HIV RNA. Virol 2002; 292:1-5.
Lin X, Gelman IH. Calmodulin and cyclin D anchoring sites on the Src-Suppressed C Kinase Substrate, SSeCKS. Biochem Biophys Res Commun 2002; 290:1368-1375.
Nelson PJ, Gelman IH, Klotman PE. Suppression of HIV-1 expression by inhibitors of cyclin-dependent kinase promotes differentiation of infected podocytes. J Am Soc Nephrol 2001; 12:2827-2831.
Xia W, Unger P, Miller L, Nelson J, Gelman IH. Suppression of prostate metastasis by re-expression of the Src-suppressed C kinase substrate, SSeCKS. Cancer Res 61:5644-5651, 2001.
Wassler MJ, Foote CI, Gelman IH, Shur BD. Functional interaction between cell surface -1,4-galactosyltransferase and SSeCKS, a PKC substrate. J Cell Sci 2001; 114:2291-2300.
Cohen SB, Waha A, Gelman IH, Vogt PK. Expression of a down-regulated target, SSeCKS, reverses v-Jun-induced transformation of 10T1/2 murine fibroblasts. Oncogene 2001; 20:141-146.
Lin X, Nelson P, Gelman IH. Regulation of G1 S progression by the SSeCKS tumor suppressor: Control of cyclin D expression and cellular compartmentalization. Molec Cell Biol 2000; 20(19):7259-7272.
Gelman IH, Tombler E, Vargas J Jr. Developmental and tissue-specific expression of SSeCKS, a major PKC substrate with tumor suppressor activity, suggests roles in cytoskeletal architecture, formation of migratory processes and cell migration during embryogenesis. The Histochem J 2000; 32:13-26, 2000.
Moissoglu K, Vargas J Jr, Klotman PE, Gelman IH. The protein kinase C substrate, SSeCKS, controls actin-based stellate morphology in mesangial cells. J Cell Sci 1999; 112:361-370.
Gelman IH, Lee K, Tombler E, Gordon R, Lin X. Control of cytoskeletal architecture by the src-suppressed C linase substrate, SSeCKS. Cell Motility and Cytoskeleton 1998; 41(1):1-17.
Nelson P and Gelman IH. Cell-cycle regulated expression and serine phosphorylation of the myristylated protein kinase C substrate, SSeCKS: Correlation with cell confluency, G0 phase and serum response. Molec Cell Biochem 1997;175:233-241.
Lin X, and Gelman IH. Re-expression of the major protein kinase C substrate, SSeCKS, suppresses v-src induced morphological transformation and oncogenic growth. Cancer Res 1997; 57(11):2304-2312.