Scientific Report 2003-2004 - Cleveland Clinic Lerner Research ...

The Department of Cancer BiologyCytokine-Mediated Cell Signalingin Cancer and InflammationOur long-term objective is to understandhomeostatic control of cytokinemediatedcell signaling in health anddisease. Currently our major focus is to define (i)the role and regulation of Stat3 signaling in thesurvival of glioblastoma cells, (ii) the cellular andmolecular mechanisms that negatively regulate IL-4-mediated signal transduction and subsequentgene expression in allergicinflammation, and (iii) signalingmechanisms underlying the growthand survival of mast cells.Cytokine Signaling in GlioblastomaCellsGlioblastoma multiforme(GBM) is the most common andmalignant form of primary braintumors, with an average survivalof less than one year. The latenttranscription factor Stat3, whenactivated by IL-6-family cytokinesand other growth factors, inducesthe expression of genes that areresponsible for suppression ofapoptosis in a variety of humancancer cells. We found that Stat3 ispersistently activated by theautocrine action of IL-6 in GBM tumor tissuesand GBM cell lines. Inhibition of Stat3 activationinduces apoptosis in these cells. We haveundertaken biochemical and molecular geneticapproaches in both tissue culture system andanimal models to investigate the molecular basesof Stat3-mediated survival of GBM cells. Inaddition, we have addressed the role of IL-13Rα2, a high-affinity non-signaling transmembraneIL-13-binding protein, in the regulation ofJak-Stat signaling in GBM cells.Cytokine Signaling in Allergic InflammationNegative Regulation of IL-4 Signaling: IL-4, apleiotropic cytokine secreted by activated Tlymphocytes, basophils and mast cells, plays a keyrole in the pathogenesis of a variety of inflammatorydisorders, including allergic asthma and otherallergic diseases. Major biological actions of IL-4in the inflammatory cells are mediated throughthe activation of the Jak-Stat pathway. Signaltransduction through this pathway can benegatively controlled at multiple levels by anumber of molecules and by different means. Wechose to focus on the roles of protein tyrosinephosphatases (PTPs) and of proteins in thesuppressors of cytokine signaling (SOCS) familyin the negative regulation of IL-4-dependent Jak-Stat signaling. Our recent work suggested thatPTP activity is a major and primary negativeregulator of the cytokine-activated Jak-Statsignaling pathway, and importantly, more thanone PTP activity is involved in this process. Wehave identified Shp-1 as a negative regulator ofIL-4-mediated cell signaling. Identification ofShp-1 substrate(s), additional PTPs and theirsubstrates in these signaling pathways is underactive investigation. To understand the SOCSmediatednegative feedback mechanisms, we havebegun to characterize the induction profile ofSOCS genes in cytokine-stimulated cells and todefine the structural basis of SOCS-mediatedregulation of the Jak-Statsignaling pathways.Signaling Mast CellGrowth and Survival. Mastcells are critical effectors ininnate immune responses andplay key roles in thepathogenesis of multipleinflammatory disorders,including asthma. Stem cellfactor (SCF) signalingthrough c-Kit is essential forproliferation and survival ofhuman mast cells. However,the precise molecularmechanisms underlying c-Kit-mediated mast cellsurvival remain unclear. TheSaikh Jaharul Haque, Ph.D.long-term goal of thisproject is to (i) identify and characterizeintracellular signaling transduction pathways thatlead to the expression and activation of prosurvivalproteins in mast cells, and (ii) target theidentified pathways in a mouse asthma model toinduce the spontaneous apoptosis of airway mastcells.THE HAQUELABORATORYRESEARCH ASSOCIATENilesh Maiti, Ph.D.PHYSICIAN SCIENTISTFred H. Hsieh, M.D.POSTDOCTORAL FELLOWSShaik Ohidar Rahaman, Ph.D.Pankaj Sharma, Ph.D.TECHNICAL ASSISTANTPhyllis C. Harbor, B.S.COLLABORATORSMark A. Aronica, M.D. 1, 2Gene H. Barnett, M.D. 3Serpil C. Erzurum, M.D. 1,4Abhijit Guha, M.D., FRCS(C) 6George R. Stark, Ph.D. 7Michael Vogelbaum, M.D., Ph.D. 3, 4Bryan R.G. Williams, Ph.D. 4Taolin Yi, Ph.D. 41Dept. of Pulmonary and CriticalCare Medicine, CCF2Dept. of Immunology, CCF3Dept. of Neuro. Surgery, CCF4Dept. of Cell. Path. St.George’sHospital Medical School, London,UK5Dept. of Cancer Biology, CCF6Dept. of Neurosurg. and Surg.Oncol., Univ. of Toronto, Toronto,Ont., Canada7Dept. of Molecular Biology, CCFGoh, K. C., Haque, S.J. and B.R.G. Williams (1999) p38 MAP kinase is required forSTAT1 serine phosphorylation and transcriptional activation induced by interferons.EMBO J. 18:5601-5608.Haque, S.J., Harbor, P.C., and B.R.G. Williams (2000) Identification of criticalresidues required for suppressor of cytokine signaling (SOCS)-specific regulationof IL-4 signaling. J. Biol Chem. 275:26500-26506.Rahaman S.O., Sharma P., Harbor P.C., Aman M.J., Vogelbaum M.A., and S.J.Haque (2002) IL-13Ra2, a decoy receptor for IL-13, acts as an inhibitor of IL-4-dependent signal transduction in glioblastoma cells. Cancer Res. 62:1103-1109.Rahaman S.O., Harbor P.C., Chernova, O., Barnett, G.H., Vogelbaum, M.A., andS.J. Haque (2002) Inhibition of constitutively active Stat3 suppresses proliferationand induces apoptosis in glioblastoma multiforme cells. Oncogene 21:8404-8413.Fox., S.W., Haque, S.J., Lovibond, A.C., and T.J. Chambers (2003) The possiblerole of transforming growth factor-β (TGF-β)-induced SOCS expression in osteoclast/macrophagelineage commitment in-vitro. J. Immunol. 170:3679-3687.Zheng, S., De, B.P., Choudhary, S., Comhair, S.A.A., Goggans, T., Slee, R.,Williams, B.R.G., Pileswski, J., Haque, S.J., and S.C. Erzurum (2003) Impairedinnate host defense causes susceptibility to respiratory virus infections in cysticfibrosis. Immunity 18:619-630.Xu, W., Comhair, S.A.A., Zheng, S., Chu, S.C., Marks-Konczalik, J., Moss, J.,Haque, S.J., and S.C. Erzurum (2003) Stat1 and c-Fos interaction in nitric oxidesynthase 2 gene activation. Am. J. Physiol. Lung Cell Mol. Physiol. 258:L137-L148.55