Effects of TLR4 siRNA on the cisplatin-induced apoptosis in human OSCC cell lines. A. CAL-27 and WSU-HN6 cell lines (5 × 105 ml-1) were transfected with NC siRNA or TLR4 siRNA for 48 h, pretreated with or without 1 μg/ml LPS for 4 h, then stimulated with 1 μg/ml cisplatin for another 24 h. The cells were stained with Annexin V and PI and subjected to flow cytometry to determine the percentage of Annexin V+PI-/Annexin V+PI+ apoptotic cells. Results are representative of three independent experiments. B. LPS could not decrease the effects of cisplatin-induced apoptosis in CAL-27 and WSU-HN6 when TLR4 was silenced. (*p < 0.05, compared with the group treated with cisplatin only).