Inhibition of human ovarian cancer cell growth in vitro and in nude mice by prostaglandin D2.

In vitro and in vivo effects of prostaglandin D2 on human ovarian tumor growth were examined by using a cell line, designated HR, derived from ascites of a patient with serous cystadenocarcinoma of the ovary. The HR cell proliferation in vitro was dose dependently inhibited between concentrations of 0.1 and 4.0 micrograms of prostaglandin D2 per ml. From results of 51Cr release assays and trypan blue dye exclusion tests the inhibitory effect seemed to result from a direct cytotoxic effect by prostaglandin D2. All DNA, RNA, and protein syntheses by the HR cells were also inhibited in a dose-dependent manner with exposure time of 48 h to prostaglandin D2. When 5 X 10(5) HR cells were inoculated to nude mice, the 50% survival time of them in untreated groups was 52 days after inoculation. Although 4 mg of prostaglandin D2 per kg caused inhibition of the tumor growth, a significant prolongation of the survival time was not observed. On the other hand, the 50% survival time of nude mice treated with 12 mg of prostaglandin D2 per kg was significantly (P less than 0.05) prolonged to 67 days, in addition to a significant inhibition of the tumor growth.