The purpose is to continue our studies on the biochemical and molecular mechanisms that underlie the process of tumor promotion. Because of the evidence that the enzyme protein kinase C (PKC) plays a central role in growth control and mediates the action of the phorbol ester tumor promoters, we will concentrate on this enzyme system. Studies from several laboratories, including our own, indicate that the mammalian genome encodes several isoforms of this enzyme. Our major strategy will be to use genetic techniques to develop derivatives of the Rat 6 fibroblast cell line that stably overexpress the beta 1, gamma, or epsilon isoforms of PKC. These cell lines will be used to determine possible biochemical differences between these isoforms, to assess their effects on growth control and synergy with oncogenes, and to develop more specific inhibitors of PKC. Using 32P-labelling of intact cells, coupled with two dimensional gel electrophoresis and immunoprecipitation methods, we will attempt to identify the major protein substrates phosphorylated in these cells and the possible roles of these phosphoproteins in mediating the effects of various isoforms of PKC. Region-specific mutations will be introduced into different domains of PKC beta 1 to assess the biochemical functions of these domains and their roles in growth control. A specific project will explore the role of PKC in activation of human T cells and in replication of the human immunodeficiency virus. We will also isolate a full length cDNA sequence for the gene TPA-R1, whose expression is inhibited by TPA, and determine whether overexpression of this sequence suppresses the transformed phenotype. A long term goal is to develop transgenic strains of mice that overexpress specific isoforms and mutant forms of PKC, to define the role of this enzyme system in the multistage carcinogenic process in the intact animal. We are hopeful that the insights obtained from these studies, and the model systems that are developed, will provide a more rational basis for detecting potential tumor promoters in our environment and lead to new strategies of cancer prevention.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
2R37CA026056-11
Application #
3482040
Study Section
Chemical Pathology Study Section (CPA)
Project Start
1979-12-01
Project End
1994-11-30
Budget Start
1989-12-01
Budget End
1990-11-30
Support Year
11
Fiscal Year
1990
Total Cost
Indirect Cost
Name
Columbia University (N.Y.)
Department
Type
Schools of Medicine
DUNS #
064931884
City
New York
State
NY
Country
United States
Zip Code
10027
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Soh, Jae-Won; Weinstein, I Bernard (2003) Roles of specific isoforms of protein kinase C in the transcriptional control of cyclin D1 and related genes. J Biol Chem 278:34709-16
Soh, Jae-Won; Weinstein, I Bernard (2003) Role of COX-independent targets of NSAIDs and related compounds in cancer prevention and treatment. Prog Exp Tumor Res 37:261-85
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Soh, J W; Lee, E H; Prywes, R et al. (1999) Novel roles of specific isoforms of protein kinase C in activation of the c-fos serum response element. Mol Cell Biol 19:1313-24

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