The percentage of viable cells in miR-128b–, miR-221–, or control–transduced RS4;11 cells treated with different concentrations of etoposide and by serum depletion. (A) Sorted GFP⁺ miR-128b–, miR-221–, or let7b–transduced cells are treated with different concentrations of etoposide for 24 hours, followed by FACS analysis. GFP⁺ cells were assessed for viability by annexin V staining in the same manner as in Figure 1A. The vertical axis represents the percentage of the number of GFP⁺ annexin V⁻ cells after etoposide treatment relative to the number of GFP⁺annexin V⁻ cells without etoposide treatment. (B) Sorted GFP⁺ miR-128b–, miR-221–, or let7b–transduced cells are treated with serum depletion for 6 and 12 hours, followed by FACS analysis. GFP⁺ cells are assessed for viability by annexin V staining in the same manner as in Figure 1A. The vertical axis shows the percentage of the number of GFP⁺ annexin V⁻ cells after serum depletion relative to the number of GFP⁺annexin V⁻ cells at 0 hour. The absolute percentage of the viable cells in control-transduced cells is 60% to 70% after sorting. Three independent experiments were done. *P < .05, let7b vs miR-221. **P < .05, let7b vs miR-128b.