Chemotherapy of L1210 leukemia with 5-azacytidine in combination with vincristine, adriamycin, or beta-cytosine arabinoside.
The cytotoxicity of vincristine (VCR), beta-cytosine arabinoside (Ara-C), or adriamycin (ADRIA) in combination with 5-azacytidine (Aza-CR) to L1210 leukemia in vivo was measured to determine if schedule-dependent synergistic or antagonistic drug interaction occurred. Two dose levels of Aza-CR were studied (0.1 and 0.5 mg/mouse), and cytotoxicity was measured by the spleen colony assay. For the combination of Aza-CR plus VCR, cytotoxicity was essentially additive or antagonistic when VCR preceded Aza-CR and additive or synergistic when VCR followed Aza-CR. When Aza-CR was combined simultaneously with either Ara-C or ADRIA, cytotoxicity was markedly antagonistic but was additive if drugs were given sequentially. When Ara-C was given as a 24-hour infusion before Aza-CR, the resultant cell kill was antagonistic (although slightly greater than that obtained for Ara-C alone). However, antagonism was even more marked when Aza-CR was given before the 24-hour infusion of Ara-C; cell kill was less than that observed with Ara-CR alone. Synergistic cytotoxicity was observed only with VCR administered after a low dose of of Aza-CR. Therefore, scheduling of drugs in combination with Aza-CR may be critical in the determination of the antileukemic cytotoxic effects.
D000818:Animals; D001374:Azacitidine / Q000627:therapeutic use*; D003114:Colony-Forming Units Assay; D003561:Cytarabine / Q000627:therapeutic use*; D004317:Doxorubicin / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D007939:Leukemia L1210 / Q000188:drug therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D014750:Vincristine / Q000627:therapeutic use*
D003561:Cytarabine; D014750:Vincristine; D004317:Doxorubicin; D001374:Azacitidine