Effect of siRNA induced down-regulation of Hsp32 in HMC-1.2 cells. (A) HMC-1.2 cells were transfected with a control siRNA (luc-siRNA) or a Hsp32-specific siRNA (Hsp32-siRNA) using lipofectin as described. Then, cells were examined for expression of the Hsp32 protein by Western blotting using antibodies against Hsp32 and β-actin (loading control). Results from nontransfected control HMC-1.2 cells (control) are also shown. As assessed by densitometry, transfection with Hsp32-siRNA resulted in a decrease in expression of the Hsp32 protein to 35% compared with untransfected cells, whereas no decrease was found in case of the Luc siRNA (165%). (B) Nontransfected HMC-1.2 cells and HMC-1.2 cells transfected with control siRNA (luc-siRNA) or an Hsp32-specific siRNA (Hsp32-siRNA) were examined for the percentage of apoptotic cells by light microscopy. Results represent the mean (± SD) of 3 independent experiments. *P < .05.