title: [Cancer stem cells promotes resistance of laryngeal squamous cancer to irradiation mediated by hypoxia].
abstract: OBJECTIVE
  To study whether cancer stem cells promotes resistance of laryngeal squamous cancer to irradiation mediated by hypoxia.
  
  
  METHODS
  Hep-2 cells were respectively cultured in hypoxia and normoxia environment, and the express of HIF-la was detected by western blot. Then they were radiated with different doses of gamma-rays. After that we detected growth inhibition ratio with MTT assay, cell circle and ratio of CD133+ cells with Flow cytometry at different times.
  
  
  RESULTS
  MTT assay showed that inhibition ratio of the hypoxia group was lower than that of the normoxia group after different doses of gamma-rays at each time point, and the difference was significant 24 h after 10 Gy irradiation (P < 0.05). The results of Flow cytometry demonstrated that cells of the two groups were arrested at G1 phase, and cells ratio in G1 phase of the hypoxia group was higher than that of he normoxia group after 10 Gy irradiation. The ratio of CD133-positive cells was higher in the hypoxia group than in the normoxia group after radiation, and difference was significant 24 h after 10 Gy irradiation (P < 0.05). In each group, the ratio of CD133-positive cells became higher after radiation than that before radiation (P < 0. 05).
  
  
  CONCLUSIONS
  We can conclude that cancer stem cells play an important role in radioresistance mediated by hypoxia.
authors.affiliation: Department of Otolaryngology Head and Neck Surgery, Bethune International Peace Hospital, Shijiazhuang, 050082, China.
authors.forename: Maoxin
authors.initials: M
authors.lastname: Wang
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Li
authors.forename: Xiuying
authors.initials: X
authors.lastname: Lu
authors.forename: Yongtao
authors.initials: Y
authors.lastname: Qu
authors.forename: Ou
authors.initials: O
authors.lastname: Xu
authors.forename: Qingjia
authors.initials: Q
authors.lastname: Sun
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000532:radiotherapy*; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D005720:Gamma Rays; D006801:Humans; D007822:Laryngeal Neoplasms / Q000532:radiotherapy*; D014411:Neoplastic Stem Cells / Q000166:cytology*; D011836:Radiation Tolerance