Optimal conditions of chemotherapeutic sensitivity in K562 cell line using tetrazolium dye assay.

Ten antineoplastic agents were used on K562 cell lines with the tetrazolium salts (MTT) assay to investigate optimal conditions of the chemotherapeutic sensitivity. The doubling time of K562 cell was 20.4 h in 96-well microtitre plates. The optical density in MTT assay of the no-drug controls was 0.77 (n = 45). A 70% reduction (IC70) in absorbance compared with control values using an ELISA reader at 570 nm was referred to as drug sensitive and < 70% (IC70) was referred to as resistant. The inhibitory effect of the theoretical maximal plasma drug concentration (Cmax) in plasma was compared with that of 10% Cmax drug concentration. At 10% Cmax after a 2-d drug exposure to daunorubicin and homoharringtonine, or after 5 d to epirubicin, 5-fluorouracil, cytarabine hydrochloride, and doxorubicin, significant cytotoxicities were shown. There were little time-dependent effects after 2-5 d drug exposure for 4 out of the 10 tested drugs, and mild or marked time- and dose-dependent effect for others.