A study by Shi-Zhong Bu, M.D., De-Ling Yin, Ph.D., Xiu-Hai Ren, Ph.D., Li-Zhen Jiang, Zhi-Jiang Wu, Qi-Rong Gao, Gang Pei, Ph.D. Shanghai Institute of Cell Biology, Chinese Academy of Sciences, Shanghai, China. ABSTRACT Progesterone (PROG) has been shown to reduce the risk of developing ovarian carcinoma in postmenopausal women who have undergone estrogen and progestogen replacement therapy, and it has been clinically used to treat some types of ovarian tumors. It is not yet clear whether or not the antitumor activity of progestogen is due to its ability to induce apoptosis in precarcinomatous and carcinomatous ovarian cells. The apoptosis-related genes p53, bcl-2, and c-myc have important roles in the regulation of programmed cell death, and thus may be involved in the process of the suspected PROG-induced apoptosis. RESULTS. In both 3AO and AO cell lines, cells proliferation was maximally inhibited by PROG after 72 hours of treatment at 10 µM concentration. Under the same conditions, more than 50% of PROG-treated cells had undergone apoptosis, whereas less than 3% of the cells were apoptotic in untreated cell cultures. After exposure to PROG for 72 hours, cells were arrested in the G1 phase of the cell cycle, and the levels of p53 mRNA were remarkably increased in both cell lines. No changes in expression of bcl-2 or c-myc weredetected. CONCLUSIONS. PROG significantly inhibited cell proliferation and induced apoptosis in both of the ovarian carcinoma cell lines tested in this study. PROG treatment markedly up-regulated p53 expression in these cells, indicating involvement of p53 in PROG-induced apoptosis. Ann's NOTE: This study was of ovarian cancer cells in a test tube. But the results are very exciting. Perhaps progesterone may be the substance that works to reduce ovarian cancer cells. Let's ask FDA or NCI to study this. Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.