Pro-survival role of HSP70 in human prostate cancer cell lines.

<p>(<b>A</b>) Three prostate cancer cell lines were treated with HT (43°C for 2 h). Before and after 4, 8, 12, and 24 h, lysates were prepared and the expression of HSP70 was assessed by immunoblot. β-Actin was used as the control. The number represents the ratio of the expression of HSP70 to that of β-actin, which was evaluated by densitometry using ImageJ. (<b>B</b>) Three days after transfection of HSP70 siRNA or control siRNA, the expression of HSP70 was assessed by immunoblot. β-Actin was used as a control. (<b>C</b>) Three cell lines, which had been pre-transfected with HSP70 siRNA or control siRNA three days before, were cultured. After 48 h, cell viability (%) was determined using the WST-8 assay. The results are shown as the mean ± SD of three wells. * <i>P</i><0.05 (Student's <i>t</i>-test) (<b>D</b>) PC-3 and DU-145, which had been pre-transfected with HSP70 siRNA or control siRNA 2 days prior, were cultured for the colony-formation assay for 12 days. The results are shown as the mean ± SD of three wells. * <i>P</i><0.05 (Student's <i>t</i>-test) (<b>E</b>) LNCaP, which had been pre-transfected with HSP70 siRNA or control siRNA 2 days prior, were cultured for 12 days, and cell viability (%) was determined using the WST-8 assay. The results are shown as the mean ± SD of three wells. * <i>P</i><0.05 (Student's <i>t</i>-test).