The major focus of this proposal is to understand the tumor suppressive properties of prohibitin, a gene located on human chromosome 17q21 close to the BRACA1 locus. Prohibitin can induce a G1/S arrest in cells, and prohibitin mutations have been found in a subset of sporadic breast cancers. No information is available on the mechanisms by which prohibitin induces a G1/S arrest. Our recent studies have shown that prohibitin can physically interact with the Rb family proteins, as well as Raf- 1, a vital signaling molecule. Prohibitin is capable of suppressing the formation of colonies in a variety of cell lines; this suppression can be reversed by Raf-1. Further, prohibitin can repress the transcriptional activity of E2F, a major down- stream target of the Rb protein. Prohibitin mediated repression of E2F activity in B-cell lines can be reversed by stimulating the IgM receptors. The experiments proposed in this application aim at understanding the molecular mechanisms by which prohibitin induces growth arrest in cells. A detailed mutational analysis of prohibitin will be conducted, to identify the region of prohibitin involved in effecting growth suppression, response to Raf-1 protein as well as inhibition of E2F activity. The mechanisms involved in prohibitin-mediated repression of E2F will be studied in detail, with special emphasis on the role of HDAC1 in this process. Attempts will also be made to understand how prohibitin function is regulated by upstream signals, especially Raf-1 and MAP kinase pathway. In the same context, the role of prohibitin in IgM receptor-mediated signaling will be established. Lastly, we will assess the status of prohibitin gene and protein in human tumors and tumor derived cell lines. We will focus on the role of prohibitin inactivation in breast carcinomas as well as B-cell lymphomas, and it will be assessed whether the mutation has contributed to a loss of growth control. We believe that the studies described in this proposal will throw light on the role of a poorly understood tumor suppressor gene in oncogenesis, and will identify novel targets for designing anti-cancer agents.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA077301-02
Application #
6173248
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Program Officer
Mietz, Judy
Project Start
1999-09-30
Project End
2001-07-31
Budget Start
2000-08-01
Budget End
2001-07-31
Support Year
2
Fiscal Year
2000
Total Cost
$231,619
Indirect Cost
Name
Columbia University (N.Y.)
Department
Pathology
Type
Schools of Medicine
DUNS #
167204994
City
New York
State
NY
Country
United States
Zip Code
10032
Rizwani, Wasia; Chellappan, Srikumar P (2015) In vitro replication assay with mammalian cell extracts. Methods Mol Biol 1288:349-62
Rizwani, Wasia; Schaal, Courtney; Kunigal, Sateesh et al. (2014) Mammalian lysine histone demethylase KDM2A regulates E2F1-mediated gene transcription in breast cancer cells. PLoS One 9:e100888
Singh, Sandeep; Johnson, Jackie; Chellappan, Srikumar (2010) Small molecule regulators of Rb-E2F pathway as modulators of transcription. Biochim Biophys Acta 1799:788-94
Pillai, Smitha; Dasgupta, Piyali; Chellappan, Srikumar P (2009) Chromatin immunoprecipitation assays: analyzing transcription factor binding and histone modifications in vivo. Methods Mol Biol 523:323-39
Pillai, Smitha; Chellappan, Srikumar P (2009) ChIP on chip assays: genome-wide analysis of transcription factor binding and histone modifications. Methods Mol Biol 523:341-66
Rizwani, Wasia; Chellappan, Srikumar P (2009) In vitro replication assay with mammalian cell extracts. Methods Mol Biol 523:203-16
Rizwani, Wasia; Alexandrow, Mark; Chellappan, Srikumar (2009) Prohibitin physically interacts with MCM proteins and inhibits mammalian DNA replication. Cell Cycle 8:1621-9
Dasgupta, Piyali; Chellappan, Srikumar P (2007) Chromatin immunoprecipitation assays: molecular analysis of chromatin modification and gene regulation. Methods Mol Biol 383:135-52
Joshi, B; Rastogi, S; Morris, M et al. (2007) Differential regulation of human YY1 and caspase 7 promoters by prohibitin through E2F1 and p53 binding sites. Biochem J 401:155-66
Rastogi, Shipra; Joshi, Bharat; Dasgupta, Piyali et al. (2006) Prohibitin facilitates cellular senescence by recruiting specific corepressors to inhibit E2F target genes. Mol Cell Biol 26:4161-71

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