title: Identification and characterization of cancer stem cells from head and neck squamous cell carcinoma cell lines.
abstract: OBJECTIVE
  Head and neck squamous cell carcinoma (HNSCC) ranks sixth worldwide for tumor-related mortality. A subpopulation of tumor cells, termed cancer stem cells (CSCs), has the ability to support cancer growth. Therefore, profiling CSC-enriched populations could be a reliable tool to study cancer biology.
  
  
  METHODS
  We performed phenotypic characterization of 7 HNSCC cell lines and evaluated the presence of CSCs. CSCs from Hep-2 cell line and HNSCC primary cultures were enriched through sphere formation and sphere-forming cells have been characterized both in vitro and in vivo. In addition, we investigated the expression levels of Nicotinamide N-methyltransferase (NNMT), an enzyme overexpressed in several malignancies.
  
  
  RESULTS
  CSC markers were markedly expressed in Hep-2 cell line, which was found to be highly tumorigenic. CSC-enriched populations displayed increased expression of CSC markers and a strong capability to form tumors in vivo. We also found an overexpression of CSC markers in tumor formed by CSC-enriched populations. Interestingly, NNMT levels were significantly higher in CSC-enriched populations compared with parental cells.
  
  
  CONCLUSIONS
  Our study provides an useful procedure for CSC identification and enrichment in HNSCC. Moreover, results obtained seem to suggest that CSCs may represent a promising target for an anticancer therapy.
authors.affiliation: Department of Clinical Sciences, Polytechnic University of Marche, Ancona, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Pozzi
authors.forename: Davide
authors.initials: D
authors.lastname: Sartini
authors.forename: Romina
authors.initials: R
authors.lastname: Rocchetti
authors.forename: Andrea
authors.initials: A
authors.lastname: Santarelli
authors.forename: Corrado
authors.initials: C
authors.lastname: Rubini
authors.forename: Stefano
authors.initials: S
authors.lastname: Morganti
authors.forename: Rachela
authors.initials: R
authors.lastname: Giuliante
authors.forename: Stefania
authors.initials: S
authors.lastname: Calabrese
authors.forename: Giulia
authors.initials: G
authors.lastname: Di Ruscio
authors.forename: Fiorenza
authors.initials: F
authors.lastname: Orlando
authors.forename: Mauro
authors.initials: M
authors.lastname: Provinciali
authors.forename: Franca
authors.initials: F
authors.lastname: Saccucci
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Lo Muzio
authors.forename: Monica
authors.initials: M
authors.lastname: Emanuelli
mesh_terms: D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000201:enzymology / Q000473:pathology*; D045744:Cell Line, Tumor; D005260:Female; D006258:Head and Neck Neoplasms / Q000201:enzymology / Q000473:pathology*; D006801:Humans; D008297:Male; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D014411:Neoplastic Stem Cells / Q000201:enzymology / Q000473:pathology*; D050903:Nicotinamide N-Methyltransferase / Q000032:analysis / Q000378:metabolism; D000077195:Squamous Cell Carcinoma of Head and Neck; D014407:Tumor Cells, Cultured
chemical_list: D050903:Nicotinamide N-Methyltransferase