Although most ovarian cancers arise from the surface epithelium, little is known regarding the biology of these cells. We have established human ovarian epithelial cells in culture to study their growth and transformation. In preliminary experiments, we have shown, 1) that epidermal growth factor stimulates proliferation of ovarian epithelial cells, and 2) that these cells both produce active transforming growth factor-beta (TGFbeta) and are growth inhibited by TGF-beta. In this proposal we will seek other peptide growth factors or steroid hormones that affect proliferation of ovarian epithelium and identify cells in the ovary that produce these factors. Relevant autocrine and paracrine growth regulatory pathways will be defined using monoclonal antibodies to neutralize the candidate growth factors or to block their receptors. Since ovulation is thought to be a stimulus to proliferation of ovarian epithelium and uninterrupted ovulation is associated with ovarian cancer, we will investigate whether the hormonal milieu after ovulation plays a role in stimulating growth of ovarian epithelium. We will test the hypothesis that estrogen or other hormones may decrease production of TGF-beta or response to this growth factor thereby down-regulating inhibition and stimulating growth. Since ovarian cancer is associated with aging, and we have shown that most ovarian cancer cell lines are relatively resistant to TGF-beta, we will examine the effect of aging on growth regulation of ovarian epithelial cells by TGF-beta. It is possible that loss of this growth inhibitory pathway with aging might play a role in the development of some ovarian cancers. We also have found that two growth regulatory genes, HER-2/neu and p53, are activated in a significant proportion of ovarian cancers. It is not known, however, whether activation of these oncogenes is an early event in ovarian carcinogenesis. To address this issue, we will evaluate expression of these-oncogenes in epithelial cells from normal ovaries and atypical ovarian epithelial cells from normal ovarian tissue in patients with early stage ovarian cancer and familial ovarian cancer. Since aging and uninterrupted ovulation have been associated with the development of ovarian cancer, we will investigate whether activation of HER-2/neu or p53 is seen more frequently in ovarian epithelial cells from older women and those with a history of uninterrupted ovulation. An increased understanding of growth regulation and transformation of human ovarian epithelium may lead to improvements in diagnosis, treatment and prevention of ovarian cancer.
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