[Comparison of the sensitivity of retinoic acid sensitive and resistant HL-60 cell lines to several anti-leukemia drugs].

By using MTT and trypan blue exclusion assay, the sensitivity of retinoic acid sensitive HL-60 and resistant HL-60/RA cell to six anti-leukemia drugs such as RA, Ara-c, harringtonine was compared. It was found that all five drugs except RA exhibited an approximately equivalent IC50 to HL-60 and HL-60/RA cells. The results suggest that tumor cells may not develop resistance to differentiation inducer and cytotoxic anti-tumor agent parallel. It also suggests that it is reasonable to use a combination of differentiation and cytotoxic anti-leukemia agents concomitantly or sequentially.