Antitumor activity of trioxacarcin C.

The novel antitumor antibiotic, trioxacarcin C, was studied for antitumor activities against murine tumor systems. When mice with i.p.-inoculated B16 melanoma were given intraperitoneal injections of trioxacarcin C, the maximal T/C% was 164 by successive administration of 0.125 mg/kg/day (day 1 approximately 10). It also gave the prolongation of life span of mice bearing i.p. P388 leukemia (T/C 141%) by i.p. injection for 10 days, and inhibited the growth of sarcoma 180 (T/C 42%) and Lewis lung carcinoma implanted s.c. (T/C 23%) by i.v. administration for 6 or 7 days. It inhibited the growth of P388 leukemia cells in vitro and showed significant inhibition on the colony formation of HeLa S3 cells. DNA and RNA synthesis were more strongly inhibited than protein synthesis by trioxacarcin C. Also, it induced strand scission of PM-2 DNA without reducing agents or metals. It did not effect the number of white blood cells and blood urea nitrogen value of the peripheral blood.