Germline mutations in the breast and ovarian cancer susceptibility gene, BRCA1, predispose carriers to dramatically elevated risks of breast and ovarian cancer. This suggests that BRCA1 plays an important role in the regulation of growth and differentiation of epithelial cells, particularly those which are hormonally responsive. Further studies of BRCA1 function will serve as a foundation for understanding how the absence or mutation of this molecule promotes carcinogenesis. As a first step towards this goal, they have analyzed the temporal and spatial pattern of Brca1 expression during normal mouse embryogenesis, in adult tissues, in the mammary gland during postnatal development, and in the mammary glands of mice whose levels of ovarian hormones have been experimentally manipulated. Their results support a role for Brca1 in the regulation of cell proliferation and differentiation in multiple tissues including mammary epithelial cells during puberty and early pregnancy. In addition, they have observed that Brca1 expression remains elevated in the mammary glands of parous mice as compared with age matched virgin controls. They hypothesize that BRCA1 plays a critical role in the regulation of cell growth and differentiation in the mammary epithelium and that it does so in a developmentally specific manner. Furthermore, they hypothesize that the parity-induced elevation in expression of this putative tumor suppressor gene may be involved in mediating the protective effect of an early first full term pregnancy on breast cancer risk. The goal of this research is to determine the mechanisms by which BRCA1 normally controls the proliferation and differentiation of mammary epithelial cells.
The specific aims of this proposal are to: (1)Determine the role of Brca1 in mammary epithelial proliferation, differentiation and development; and (II) Determine the role of Brca1 in the parity-induced reduction of breast cancer risk. The overall approach described in this proposal is to: 1) characterize the regulation of Brca1 expression as a function of differentiation both in vivo in the mouse and in vitro in defined model systems of proliferation and differentiation; 2) determine the effect of Brca1 overexpression on the ability of the mammary epithelium to proliferate and differentiate in vitro and in vivo in transgenic mice; 3) determine the effect of abolishing Brca1 expression on the differentiation and development of the mammary epithelium in vivo; and 4) determine the contribution made by Brca1 towards the parity induced reduction in breast cancer risk. Ultimately, understanding the role played by BRCA1 in the regulation of these processes has the potential to lead to novel strategies for the prevention and treatment of breast cancer.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA071513-04
Application #
2895598
Study Section
Pathology B Study Section (PTHB)
Program Officer
Mohla, Suresh
Project Start
1996-09-15
Project End
2001-06-30
Budget Start
1999-07-01
Budget End
2000-06-30
Support Year
4
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Huber, L J; Yang, T W; Sarkisian, C J et al. (2001) Impaired DNA damage response in cells expressing an exon 11-deleted murine Brca1 variant that localizes to nuclear foci. Mol Cell Biol 21:4005-15
Sarkisian, C J; Master, S R; Huber, L J et al. (2001) Analysis of murine Brca2 reveals conservation of protein-protein interactions but differences in nuclear localization signals. J Biol Chem 276:37640-8
Gardner, H P; Wertheim, G B; Ha, S I et al. (2000) Cloning and characterization of Hunk, a novel mammalian SNF1-related protein kinase. Genomics 63:46-59
Gardner, H P; Ha, S I; Reynolds, C et al. (2000) The caM kinase, Pnck, is spatially and temporally regulated during murine mammary gland development and may identify an epithelial cell subtype involved in breast cancer. Cancer Res 60:5571-7
Chodosh, L A; Gardner, H P; Rajan, J V et al. (2000) Protein kinase expression during murine mammary development. Dev Biol 219:259-76
Gardner, H P; Rajan, J V; Ha, S I et al. (2000) Cloning, characterization, and chromosomal localization of Pnck, a Ca(2+)/calmodulin-dependent protein kinase. Genomics 63:279-88
Chodosh, L A; D'Cruz, C M; Gardner, H P et al. (1999) Mammary gland development, reproductive history, and breast cancer risk. Cancer Res 59:1765-1771s;discussion 1771s-177
Chodosh, L A (1998) Expression of BRCA1 and BRCA2 in normal and neoplastic cells. J Mammary Gland Biol Neoplasia 3:389-402
Stairs, D B; Perry Gardner, H; Ha, S I et al. (1998) Cloning and characterization of Krct, a member of a novel subfamily of serine/threonine kinases. Hum Mol Genet 7:2157-66
Jensen, D E; Proctor, M; Marquis, S T et al. (1998) BAP1: a novel ubiquitin hydrolase which binds to the BRCA1 RING finger and enhances BRCA1-mediated cell growth suppression. Oncogene 16:1097-112

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