[Effect of prostaglandin D2 on the growth of mouse glioma]

Prostaglandin (PG) D2 was examined for its effect on the growth of a mouse brain tumor cell line in vitro and in vivo. In this study, we used 203 glioma which had been originally induced by methylcholanthrene in C57BL mice and proved to be subcutaneously transplantable and also maintainable in a cell culture system in vitro. Marked inhibition of cell growth was observed in a PGD2-treated group in vitro at a concentration of 5 micrograms/ml. In the in vivo experiment, intraperitoneal or intratumoral administration of PGD2 (0.5 mg/kg) every day for four weeks was started after subcutaneous transplantation. In a control group, the same amount of ethanol without PGD2 was administered. Inhibition of tumor growth was seen with intratumoral administration, although no inhibition was seen with intraperitoneal administration. Histological examination revealed no remarkable change after PGD2 administration. However, on the DNA histogram, an increment of the G0G1 phase and a decrement of the G2M phase occurred after intratumoral administration of PGD2. It was suggested that local administration of PGD2 might be effective through the inhibition of DNA synthesis.