Cytotoxic effect of VitD
and ATO combination treatment on human leukemia (HL-60) cells. HL-60 cells were cultured in the absence or presence of vitD3 and ATO or in combination of VitD3 and ATO for 24 hr as indicated in the Materials and Methods. Cell viability was determined based on the MTT assay. Each point represents a mean value and standard deviation of 3 experiments with 6 replicates per dose. *Significantly different from the control by ANOVA Dunnett’s test; p < 0.05. **Significantly different from ATO alone by ANOVA Dunnett’s test; p < 0.05.