HSP70 downregulation enhances cisplatin-induced HGC-27 cell apoptosis. HGC-27 cells were transfected with HSP70 shRNA plasmid and control plasmid, and at 48 h post-transfection, cells were stimulated with 5 µ g/ml cisplatin for the indicated times. (A) The morphology of apoptotic cell nuclei was detected by DAPI staining (magnification, ×100). (B) Expression levels of apoptosis-related proteins PARP, pro-caspase-3 and cleaved caspase-3 were detected by western blotting. (C) Flow cytometry was used to determine apoptosis rates (representative plots and quantification is shown). ** P