Prostaglandin D2 inhibits the proliferation of human malignant tumor cells

The cytotoxic effect of prostaglandin (PG) D2, PGE1 and PGF2 alpha was examined on human osteosarcoma cells (KSu cell line) in vitro, and PGD2 was most effective. DNA, RNA and protein syntheses of KSu cells were also found to be inhibited by PGD2 at a concentration of 5 micrograms/ml. Furthermore, the proliferation of various human malignant tumor cells was inhibited by PGD2 without exception so far. These results suggest that PGD2 shows an anti-neoplastic effect on a variety of human malignant tumor cells.