Antitumor activity of cytogenin.

Antitumor effect of cytogenin against IMC carcinoma in mice was investigated. Since cytogenin did not show cytotoxicity against tumor cells in vitro at 50 micrograms/ml and toxicity at more than 2,000 mg/kg i.p., it was considered that the antitumor effect is due to host mediated events. Cytogenin showed antitumor activity against a syngeneic murine transplantable tumor, IMC carcinoma by oral administration depending upon schedule of administration. The optimum effect was observed by the administration starting day 8 after transplantation of tumor cells, every other day for 10 times or every 2nd day for 7 times. The antitumor effect was reduced in immunosuppressed mice given anti-asialo GM1 serum and in athymic mice, but not in mice irradiated with X ray. The antitumor effector cells activated by cytogenin were determined to be macrophages and T cells.