FIGURE 5.
HSP70B′ regulates cell proliferation and survival. A, transfection with HSP70B′-GFP induced decreased cell proliferation compared with HSP70-GFP in RAW 264.7 cells. Cells were transfected with HSP70B′-GFP or HSP70-GFP, maintained in complete media, and then counted at 6, 12, 24, 48, 72, and 96 h post-transfection using a Nexcelom Auto T4 CellometerTM. Plotted values are means ± S.D. (error bars) of triplicate values. Data were analyzed by one-way analysis of variance; different letters denote significant differences among means at each time point (p < 0.05). Results are representative of three independent experiments. B, knockdown of HSP70B′ inhibited oxLDL-induced cell death in U937 cells. Upper panel, cells were transfected with scrambled siRNA (sc) or HSP70B′ siRNA and then treated with oxLDL or oxLDL-IC (150 μg/ml) for 72 h; cell viability was assessed using a CyQUANT DNA assay. Plotted values are means ± S.D. of triplicate values. Differences between means within treatment were evaluated by Student's t test (p < 0.05). *, significant difference between scrambled siRNA-transfected and HSP70B′ siRNA-transfected cells treated with oxLDL-IC but not oxLDL. Results are representative of three independent experiments. Lower panel, cells transfected with scrambled or HSP70B′ siRNA then induced with oxLDL (150 μg/ml) for 2, 6, and 12 h; an equal amount of protein (20 μg) was separated on SDS-PAGE, probed for HSP70B′, and then re-probed for HSP70.