Improvement of efficacy of antitumor agents by conagenin.

The antitumor efficacy of antitumor agents at sublethal doses was investigated in combination with conagenin (CNG) against murine leukemias. Mice were inoculated with 1 x 10(3) L1210 cells i.v. and given 300 mg/kg of cyclophosphamide (CY) i.p. on days 1 and 2 or on days 1, 5 and 9 after the tumor inoculation, and 5 mg/kg of CNG daily for 10 days. The administration of CNG was effective in increasing the number of cured mice and in prolonging the survival period of mice significantly, on both schedules of CY treatment. Moreover, the antitumor effect of CY against EL-4 was enhanced by CNG in increasing the number of cured mice, in CY treatment on days 1 and 2, and on days 1, 5 and 9. The effect of CNG was examined with mitomycin C (MMC) and adriamycin (ADM) at sublethal doses against leukemias. The antitumor effects of MMC at 10 mg/kg against L1210, and ADM at 15 mg/kg against P388 administered on days 1 and 5 were enhanced by CNG. Although mice treated with ADM at 15 mg/kg died earlier than non-treated controls on days 1 and 2 against L1210, P388 and EL-4, CNG with ADM was effective in prolonging the survival period.