E3-ligase Skp2 predicts poor prognosis and maintains cancer stem cell pool in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is one of the severe head and neck carcinomas, which is rare in west countries but has high incidence in Southern Asia especially South China. Although NPC is relatively sensitive to radiotherapy, the prognosis of patients is poor due to the advanced stage at the time of diagnosis. Therefore, it is important to understand the mechanisms involved in tumorigenesis and develop early diagnostic techniques. S-phase kinase associated protein 2 (Skp2) is overexpressed in several human cancers and associates with poor prognosis. However, its function in NPC has not been fully addressed. In this study we found Skp2 was highly expressed in NPC specimen and correlated with poor prognosis. We generated Skp2 knockdown cells to further delineate its role in NPC development. Knockdown of Skp2 partially reduced cell proliferation, promoted cellular senescence, and decreased the population of stem cell like aldehyde dehydrogenase1 positive cells as well as their self-renewal ability. Our study not only interprets the predictive role of Skp2 in the poor prognosis of NPC patients, but also reveals that Skp2 regulates the NPC cancer stem cell maintenance, which shed lights on the target therapy and early diagnosis of NPC in clinical application.