Potentiation of anticancer agents by amphotericin B.

Amphotericin B (AmB) has been shown to potentiate the cytotoxicity of several different anticancer agents in AKR mice. The extent of potentiation, as assessed quantitatively by a spleen colony assay, varied from a factor of approximately 3 for 1,3-bis(2-chlorethyl)-1-nitrosourea (BCNU) to over 100 for a number of alkylating agents and to over 1,000 for 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea. Most phase-specific agents showed little potentiation of cytotoxicity by AmB. A dose-response effect was noted with both BCNU and adriamycin, with increased potentiation being observed with increasing doses of the anticancer agents. The effect on increase in life-span was also studied and for most of the combinations it correlated with the potentiating effects disclosed by the spleen colony assay. Such a correlation was not found for AmB combined with either BCNU or vincristine.