Cancer stem cells from head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide, and its incidence is still increasing. According to cancer stem cell (CSC) theory, a distinct subpopulation of tumor cells, termed CSC, possesses the ability to self-renew, differentiate, initiate and maintain tumorigenesis. CSC enrichment from Hep-2 cell line and HNSCC primary cultures was obtained through sphere formation, by cultivating cell line in defined serum-free medium. Real-Time PCR and immunocytochemical analysis were performed to characterize CSCs. CSC-enriched populations showed an increased expression of stem cell markers and a strong capability to form tumor in vivo. Interestingly, NNMT levels were significantly higher in CSC-enriched populations compared with parental cells. The study provides an useful procedure to identify and enrich CSCs from Hep-2 cell line, allowing their molecular and phenotypic characterization. Therefore, the work may help to explore the etiopathogenetic role of CSCs in HNSCC and may contribute to the development of new strategies for head and neck cancer therapy.