Fig. 8.

Exogenous SLPI reverses E6-mediated activation of NF-κB and Akt pathways in E6-expressing HNSCC cells. a NF-κB luciferase reporter assay demonstrated that administration of SLPI abolished the increase of NF-κB activities caused by E6 oncoprotein in HNSCC cells. b Western blot analysis showed that SLPI presented a suppressive effect on the phosphorylation of p65 and IκBα, and prevented the degradation of IκBα. c Nuclear and cytoplasmic proteins were extracted from cells and it was demonstrated that SLPI inhibited the translocation of p65 from the cytoplasm to the nucleus caused by E6 oncogene in HNSCC cells. d SLPI could reverse E6-mediated activation of Akt signaling pathway. e, f Specific inhibitors of NF-κB (PDTC, Beyotime) and Akt pathways (MK-2206, Selleck) were utilized to demonstrate that the effect of SLPI on HPV E6-expressing HNSCC cells may be obtained by mediating NF-κB and Akt pathways. *P < 0.05. **P < 0.01. ****P < 0.0001