Cancer stem cells play an important role in resistance of laryngeal squamous cancer to irradiation mediated by hypoxia

• Published in: Zhonghua er bi yan hou tou jing wai ke za zhi = Chinese journal of otorhinolaryngology head and neck surgery Vol. 46; no. 12; p. 1024
• Main Authors: Wang, Mao-xin, Li, Xiao-ming, Zhao, Yong, Lu, Xiu-ying, Qu, Yong-tao, Xu, Ou, Sun, Qing-jia
• Format: Journal Article
• Language: Chinese
• Published: China 01.12.2011
• Subjects: Cell Hypoxia; Cell Line, Tumor; Flow Cytometry; Humans; Hypoxia-Inducible Factor 1, alpha Subunit - metabolism; Laryngeal Neoplasms - metabolism; Laryngeal Neoplasms - radiotherapy; Neoplastic Stem Cells - metabolism; Oxygen - metabolism
• ISSN: 1673-0860

To study whether laryngeal cancer stem cells in hypoxia have the characteristic of resistance to irradiation and underlying mechanism. CD133(+) cells were separated from Hep-2 cells with flow cytometry (FCM) and the purity was 92.8%. The separated CD133(+) cells were cultured in serum-free medium in hypoxia in normoxia environment respectively, and hypoxia-inducible factor 1 alpha (HIF-1α) expression was detected by FCM. The cells were exposed respectively to X-rays emitted by linear accelerator with a dose of 0, 5, 10, 15 or 20 Gy for 24 hours, with additional time points of 12, 36, and 48 hours for the cells exposed to 10 Gy. Then the growth inhibition ratios of cells in hypoxia and normoxia groups were detected with MTT assay at different time points. Soft agar colony formation assay was used to detect colony formation ratios of cells in hypoxia and normoxia groups. DNA dependent protein kinase catalytic subunit (DNA-PKcs), ataxia telangiectasia mutate (ATM), Survivin and P53 were detected by FCM. Growth i