Comparison of the antileukemic activity of 5-AZA-2'-deoxycytidine, 1-beta-D-arabinofuranosylcytosine and 5-azacytidine against L1210 leukemia.

The antineoplastic activity and effect on DNA synthesis and DNA methylation of 5-aza-2'-deoxycytidine (5-AZA-CdR), 1-beta-D-arabinofuranosylcytosine (ARA-C), and 5-azacytidine (5-AZA-CR) on L1210 leukemic cells were compared. At equimolar concentrations 5-AZA-CdR produced greater growth inhibition and more cytotoxicity against the L1210 cells than either ARA-C or 5-AZA-CR. ARA-C, but not 5-AZA-CdR or 5-AZA-CR, produced a potent inhibition of DNA synthesis in the L1210 cells. 5-AZA-CdR and 5-AZA-CR, but not ARA-C, inhibited DNA methylation with 5-AZA-CdR being a more effective inhibitor than 5-AZA-CR. At maximum tolerated dose, 5-AZA-CdR produced a much greater increase in life span of mice with L1210 leukemia than ARA-C or 5-AZA-CR. These in vitro and in vivo studies indicate that 5-AZA-CdR is a more potent antineoplastic agent against L1210 leukemic cells than either ARA-C or 5-AZA-CR.