Potentiation by vitamin A of the action of anticancer agents against murine tumors.

Abstract

Combinations of retinol palmitate (RP) and six different anticancer agents were examined to determine their effects on the life-span of mice bearing ascites sarcoma 180 or P388 leukemia. With ascites sarcoma 180, administration of a fixed dose of RP (3.3 mg/kg) considerably enhanced the antitumor effects of 5-fluorouracil (5-FU) (5 mg/kg, or 20 mg/kg), methotrexate (MTX) (0.5 mg/kg, or 1 mg/kg) and 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU) (12.5 mg/kg), when given by intraperitoneal injection. However RP failed to potentiate the antitumor effects of adriamycin (ADM) and 6-mercaptopurine (6-MP) against sarcoma 180. With P388 leukemia, RP (167 mg/kg, or 333 mg/kg) enhanced the antitumor effects of 6-MP (25 mg/kg, or 50 mg/kg), MTX (1 mg/kg, or 2 mg/kg), ADM (0.2 mg/kg), ACNU (5 mg/kg) and cis-dichlorodiammine-platinum (CDDP) (1 mg/kg) to a considerable extent, but it did not potentiate the antitumor effect of 5-FU. The combination of RP with ACNU or CDDP was particularly effective against P388 leukemia.