Table 1.

IC50 (paclitaxel, vincristine, bleomycin), apoptosis rate, and caspase activity in MCF7 cells at different phases; cells transfected with Twist siRNA or pCMV-Twist1; and cells pretreated with PFT-α after trasient Adriamycin exposure

MCF7Adriamycin-treated MCF7Adriamycin-treated MCF7 synchronized at G1/S phaseAdriamycin-treated MCF7 synchronized at G2/M phaseAdriamycin-treated dsRNA-transfected MCF7Adriamycin-treated Twist1 siRNA–transfected MCF7Adriamycin-treated pCMV-transfected MCF7Adriamycin-treated pCMV-Twist1–transfected MCF7PFT-α–pretreated MCF7Adriamycin-treated PFT-α–pretreated MCF7
Drugs
    Paclitaxel0.0156 ± 0.01830.7562 ± 0.0238*1.1365 ± 0.0421*0.0103 ± 0.00560.7964 ± 0.03581*0.2492 ± 0.0351
    Vincristine0.3286 ± 0.09319.2321 ± 0.3561*11.5638 ± 0.3397*0.1867 ± 0.00488.9637 ± 0.2886*4.3688 ± 0.5294
    Bleomycin0.5644 ± 0.03394.8621 ± 0.3723*5.2139 ± 0.2589*0.3742 ± 0.01584.6630 ± 0.3051*1.6197 ± 0.3513
Apoptosis rate0.0151 ± 0.00070.5239 ± 0.0143*0.1419 ± 0.00510.8862 ± 0.0287**0.4933 ± 0.0122*0.8239 ± 0.0284*0.5367 ± 0.0180.0525 ± 0.0090.0293 ± 0.00040.0622 ± 0.0003
Caspase activity (fold increase)
    Cas-1 (substrate IV)12.3 ± 0.23*1.21 ± 0.143.77 ± 0.34**2.18 ± 0.25*4.29 ± 0.36*2.18 ± 0.251.23 ± 0.281.07 ± 0.081.04 ± 0.04
    Cas-1 (substrate VII)11.8 ± 0.051.27 ± 0.134.02 ± 0.39*1.75 ± 0.14*4.56 ± 0.381.75 ± 0.141.86 ± 0.171.15 ± 0.091.08 ± 0.15
    Cas-312.6 ± 0.21*1.29 ± 0.116.38 ± 0.40**2.62 ± 0.27*7.21 ± 0.45*2.62 ± 0.271.55 ± 0.201.03 ± 0.101.05 ± 0.12
    Cas-612.9 ± 0.16*1.20 ± 0.176.29 ± 0.33**2.98 ± 0.30*6.98 ± 0.41*2.98 ± 0.301.70 ± 0.261.00 ± 0.111.13 ± 0.07
    Cas-811.3 ± 0.091.34 ± 0.125.91 ± 0.38*1.30 ± 0.11*5.44 ± 0.331.30 ± 0.111.25 ± 0.131.11 ± 0.061.09 ± 0.09
  • NOTE: IC50 values were expressed in μmol/L. Cell apoptosis rate was evaluated by flow cytometry. Caspase activity in nontreated cells was set as 1. Each assay was done in triplicate and repeated in triplicate, and all data were presented with mean ± SE. SDs for all of the experiments done in triplicate were <5%.

    Abbreviations: IC50, half maximal inhibitory concentration; dsRNA, double-stranded RNA; PFT-α, pifithrin-α.

  • * P < 0.05 versus control cells.