With differential display PCR, the PI has identified and cloned a novel gene, NOEY2, which is expressed in normal ovarian surface epithelium (OSE) and normal breast epithelium, but not in the majority of ovarian and breast cancers. Immunohistochemical analysis using Mabs developed in PI's lab has detected NOEY2 in the putative precursors of ovarian cancer including epithelial cells from the surface of normal ovaries, as well as in cells lining ovarian cysts. A 1.9Kb NOEY2 mRNA and 26kDa protein were detected in each of 11 OSE cultures. By contrast, NOEY2 expression was lost in 11 of 12 ovarian cancer cell lines, 9 of 9 primary ovarian cancer cell specimens from ascites and 5 of 7 paraffin blocks of solid ovarian Cas. NOEY2 was localized to chromosome 1p31, where loss of heterozygosity has been demonstrated in 42% ovarian cancers. The genomic sequence of NOEY2 has been obtained; NOEY2 promote sequence variation or hypermethylation within promoter region has been observed in 7 of 17 ovarian and breast cancer cell lines. As NOEY2 is a member of the ras superfamily sharing 54-62% homology with Ras and Rap family members. The effector domain of NOEY2 is altered, consistent with a different mechanism of action. Transfection of NOEY2 inhibited the proliferation of both ovarian and breast cancer cell lines that lack expression of NOEY2 but did not alter the growth of lung cancer cell line that expressed endogenous NOEY2. Expression of NOEY2 induced p21WAF1/CIP1, inhibited the cyclin D1 promoter and induced apoptosis. NOEY2 transgenic mice have been generated and are all small in size similar to cyclin Dl KO mice. The PI will determine whether NOEY2 is indeed a tumor suppressor gene, attempt to understand its mode of action and evaluate the potential for its expression for prognostication and gene therapy.
The specific aims are 1) to evaluate a) the clinical significance and b) mechanism of loss of NOEY2 expression in malignant ovarian epi cells, 2) to determine the effect of NOEY2 expression on proliferation, invasion, metastasis and survival of ovarian cancer cells, 3) to determine the mechanism by which NOEY2 interferes with signal transduction to inhibit cell proliferation, and 4) to test the NOEY2 for gene therapy for human ovarian cancer xenografts with or without the addition of cytotoxic drugs.
|Luo, R Z; Peng, H; Xu, F et al. (2001) Genomic structure and promoter characterization of an imprinted tumor suppressor gene ARHI. Biochim Biophys Acta 1519:216-22|
|Peng, H; Xu, F; Pershad, R et al. (2000) ARHI is the center of allelic deletion on chromosome 1p31 in ovarian and breast cancers. Int J Cancer 86:690-4|
|Xu, F; Xia, W; Luo, R Z et al. (2000) The human ARHI tumor suppressor gene inhibits lactation and growth in transgenic mice. Cancer Res 60:4913-20|
|Yu, Y; Xu, F; Peng, H et al. (1999) NOEY2 (ARHI), an imprinted putative tumor suppressor gene in ovarian and breast carcinomas. Proc Natl Acad Sci U S A 96:214-9|