<p>A) ELISA of intracellular IL-1β from untreated immortalized HPV-positive cells and cells incubated with 10 µM of the proteasome inhibitor MG132 for 6 h. B) Western blot analysis of pro-IL1β and p53 in immortalized keratinocytes after inhibition of deubiquitinases using PR-619 (10 µM) for 6 h prior to protein extraction. C) Detection of poly-ubiquitinated pro-IL-1β in immortalized keratinocytes by Western blotting. Cells were treated with MG132 for 6 h prior to protein extraction and pull-down of ubiquitinated proteins was performed by the tandem ubiquitin-binding entities technique (TUBE-PD, right panel). Left panel: input, representing 2.5% of the total protein extract. D) Confocal microscopy analysis of IL-1β (green) in immE6 cells after knock-down of E6-AP by siRNA or scrambled siRNA delivery used as a control. Nuclei (blue) were stained using Hoechst dye solution; scale bars represent 10 µm. E) Western blot analysis of pro-IL-1β after the knock-down of E6-AP. F) ELISA of intracellular IL-1β from immortalized HPV-positive cells after the knock-down of E6-AP by siRNA (+) or control knock-down.(−) G) ELISA of IL-1β secretion from immortalized HPV-positive cells after E6-AP knock-down and/or after NALP3 inflammasome activation using 50 µM of nigericine for 6 h. H) Knock-down of p53 and/or E6-AP in immortalized cells. Cells were transfected with 30 pmoles of the respective siRNA against E6-AP or p53 and incubated for 72 h prior to protein extraction and Western blot analysis. The bar graphs shown in A (ANOVA ***p<0.05), D (ANOVA ***p<0.001, **p<0.01) F and G (ANOVA ***p<0.001) represent the mean levels (± SEM) of three independent experiments.</p
