HSP70 depletion sensitizes cells to Pter.

<p>A) Representative HSP70 and GAPDH (loading control) immunoblots of proteins extracted from indicated cells. Densitometric analysis of the immunoblots (n = 3) are shown below. B) Inhibition of HSP70 expression by siRNA. Cells were transfected with HSP70 siRNA or GAPDH SiRNA (positive control). Protein levels were measured by western blotting. C) HT29 and MCF7 cells were seeded and transfected with HSP70 siRNA 24 h later. Pter was added at 24 h post-transfection. Cell viability was performed by sulforhodamine B colorimetric assay 48 h later. The number of replicates per experiment was at least six (n = 3). The results were statistically analyzed by ANOVA and the Tukey test (*p<0.05; ***p<0.001 vs. control). D) Cysteine and aspartyl cathepsins were determined in HT29 and MCF7 cells 72 h post- HSP70 siRNA transfection and 24 h after Pter treatment (n = 6). The results were statistically analyzed by ANOVA and the Tukey test (***p<0.001 vs. Pter 50µM).