Fig. 2

SR-T100 induced mitochondria-dependent apoptosis in primary epithelial cells expressing different types of HPV-E6/E7. a The apoptotic-associated proteins TNF-R1 and Fas were detected by western blot. Lysates were collected after the cells were infected with the Lenti-HPV6b-E6/E7, Lenti-HPV11-E6/E7, Lenti-HPV16-E6/E7 and Lenti-HPV18-E6/E7 viruses and treated with or without SR-T100 (5 μg/ml) for 12 h. Note that the TNF-R1 and Fas expression levels did not increase after SR-T100 treatment. b SR-T100 reduced MMP. Primary epithelial cells expressing different types of HPV-E6/E7 were treated with SR-T100 (5 μg/ml) for 12 h (lower panel) and stained with DiOC6(3) to measure MMP by flow cytometry. HeLa cells that had been treated with cisplatin (150 μM) for 24 h (upper panel) were used as the positive control. c Histograms of low-DiOC6(3) fluorescence-gated (M1) cells expressing different types of HPV-E6/E7. The data represent the mean ± SD of three independent experiments. **p < 0.01, HPV6b or HPV11 versus HPV16 or HPV18. d SR-T100 induced caspase-9 and -3 activation but not caspase-8 activation. Caspases-3, −8, and −9 activities were detected in primary epithelial cells expressing different types of HPV-E6/E7 before and after SR-T100 (5 μg/ml) treatment for 12 h. Note that no caspase-8 activation was observed after SR-T100 treatment, and caspase-9 and -3 activation was increased in HPV6b-E6/E7- and HPV11-E6/E7-expressing cells compared with HPV16-E6/E7- and HPV18-E6/E7-expressing cells, *p < 0.05, HPV6b or HPV11 versus HPV16 or HPV18