[Inhibition of human ovarian cancer cell growth by prostaglandin D2].

The effects of prostaglandin D2 (PGD2) on human ovarian tumor growth were examined in vitro and in vivo by using a cell line, designated HR, derived from patients with serous cystadenocarcinoma of the ovary. The cell proliferation was dose-dependently inhibited by PGD2 between concentrations of 0.1 and 4.0 micrograms/ml after 24 hrs, 48 hrs and 72 hrs of contact time. Concentrations of PGD2 required for 50% inhibition of the cell proliferation were 2.0, 1.1 and 0.55 micrograms/ml with 24, 48 and 72 hrs of contact time, respectively. From the results of 51Cr-release assay, the inhibition of cell proliferation by PGD2 was considered to result from the direct cytotoxic effects. The incorporations of 3H-thymidine, 3H-uridine and 3H-valine were inhibited in a dose-dependent fashion with more than 1.0 micrograms/ml of PGD2. Tumor growth in nude mice treated with 0.3 mg/mouse PGD2 was significantly inhibited, compared to that of untreated nude mice. In untreated nude mice the tumor growth curve was parallel to the changes in the plasma alpha-hydroxybutyrate dehydrogenase (HBD). In both PGD2-treated groups with 0.1 mg/mouse and 0.3 mg/mouse, the HBD activity markedly decreased on the 14th and the 21st day after inoculation. The 50% survival time in untreated mouse, 0.1 mg/mouse and 0.3 mg/mouse PGD2-treated groups was 52 days, 55 days and 67 days, each respectively.