Figure 6.

miRNA combinations can modulate both docetaxel sensitivity and cancer cell proliferation. (a–h) Scatter plots comparing the drug-sensitization and proliferation-modulating effects of three-wise miRNA combinations with their respective single and two-wise combinations. Relative cell viabilities for 3-day docetaxel (25 nM)-treated versus vehicle-treated OVCAR8-ADR cells and absorbances (OD₅₇₀ - OD₆₅₀) for 7-day versus 1-day cultured cells were determined by MTT assays. Drug-sensitivity (y-axis; n ≥ 5) and cell-proliferation (x-axis; n ≥ 3) indexes were obtained by dividing the relative viability and absorbance determined for each miRNA combination by that for the empty vector control without miRNA. All data were obtained from the same sets of experiments. To enable comparisons between the three-wise miRNA combinations with their respective single and two-wise combinations, data for the same miRNA or miRNA combinations are repeated in the plots. (i,j) Combinatorial expression of the miR-16-1/15a cluster, miR-128b, and the let-7e/miR-99b cluster with docetaxel achieved significantly enhanced overall anti-cancer effects. OVCAR8-ADR cells infected with the indicated miRNA combinations were treated with 25 nM of docetaxel for 3 days. Viable cell numbers were determined by the trypan blue exclusion assay (i). The docetaxel-treated cells were cultured for another 11 days, and stained with crystal violet. The colony area percentage for each sample was quantified (j). Data represent mean ± s.d. (n = 3). *P < 0.05.