PTGS2 and nasopharyngeal carcinoma: To determine the role of AP-2α/COX-2 signaling pathway in the regulation of the growth of NPC cells, we examined the effect of knockdown of AP-2α by Dotap-based AP-2α siRNA nanoparticles (si-AP2) on cell viability in various kinds of human NPC cell lines, including high differentiated cell line CNE1, low differentiated cell line CNE2 and the other two cell lines SUNE1 and HONE1, by MTT analysis.