Data are mean of 3 independent experiments ± SEM. CEM cells were stimulated with doxorubicin (30 ng/mL) and/or VCR (30 ng/mL) or left untreated (Control), as in Figure 1A using 96-well plates. Consecutive light microscopy pictures were taken for 7 days to detect new colony formation. Drug concentrations were reduced compared with the experimental setting in Figure 1, according to lower cell density.

P < .05, comparing new colony formation after VCR alone with the combined doxorubicin + VCR treatment.