Overexpressed p53 is functionally impaired by HPV E6. (A) HTet23p53, HTet26p53 or HTet43GFP cells were transfected with vector or HPV18 E6 plasmid and 18 h post transfection cells were treated with OA 1 h prior to Dox addition. MTT assay was performed after 48 h. Bar represents variations among the wells of an experiment done twice in triplicate. * Indicates P < 0.01 (B) HTet26p53 cells were transfected with HPV18 E6 plasmid and treated as mentioned in A and immunoprecipitation was performed first with E6 antibody (first IP) and secondly by p53 antibody. p53 or E6 was detected in immunoprecipitated complex. (C) p53 post-IP (second IP) following E6 IP was performed and p53 or phospho-p53detection by western blotting was performed. (D) Cells were transfected with p21luciferase construct with or without HPV18 E6 plasmid and treated as mentioned in A. Luciferase assay was performed and luciferase/GFP reading was plotted. Bar represents results from an experiment done in triplicate. (± SE). * Indicates P < 0.05.