High Expression of p21 as a Potential Therapeutic Target in Ovarian Clear-cell Carcinoma.

DNA damage response (DDR), wherein p21 is a cell fate determinant, is a potential cancer therapeutic target. Molecular expression during DDR was explored in ovarian clear-cell carcinoma (CCC). CHK1, CHK2, TP53 and p21 expression in DDR was examined using immunostaining in surgical sections of CCC (n=22). Molecular alterations in two types of CCC cell lines, JHOC-5 and JHOC-9, were investigated using western blot analysis. Expression of DDR-associated molecules was noted in most patients. While high p21 expression was found in half of the patients, the remaining patients exhibited low p21 expression. Treatment with UC2288, a p21 inhibitor, attenuated proliferation of both cell lines, more prominently in JHOC-9, resulting in reduced viability and subsequent apoptosis. p21 Inhibitor induced cell death in cells with high p21 expression, suggesting that p21 suppression can be a therapeutic strategy to treat patients with CCC.