title: ShRNA-mediated Ku80 gene silencing inhibits cell proliferation and sensitizes to gamma-radiation and mitomycin C-induced apoptosis in esophageal squamous cell carcinoma lines.
abstract: To investigate the effects of Ku80 depletion on cell growth and sensitization to gamma-radiation and MMC-induced apoptosis in esophageal squamous cell carcinoma lines. Six human carcinoma cell lines (LNcaP, K562, MDA-MB-231, MCF-7, EC9706, and K150) and normal HEK293 cell line were examined for basal levels of Ku80 protein by western blotting analysis. The suppression of Ku80 expression was performed using vector-based shRNA in EC9706 cells. Cell proliferation was determined with MTT assay and colony formation assay and tumorigenicity in a xenograft model in vitro and in vivo. Sensitivity of EC9706 cells treated with shRNA vector to gamma-radiation and MMC was determined with colony formation assay and MTT assay. The cell cycle distribution was determined by Flow cytometry. Apoptosis induced by gamma-radiation and MMC was analyzed using GENMED-TUNEL FACS kit. Ku80 showed higher basal levels in six carcinoma cell lines than in HEK293. The suppression of Ku80 expression decreased cellular proliferation, colony formation and inhibited tumorigenicity in a xenograft model. Furthermore, it sensitized apoptosis of the cancer cells induced by gamma-radiation and MMC. Ku80 plays an important role not only in tumorigenesis but also in radiation resistance and chemotherapy resistance in esophageal cancer cells. Hence Ku80 may serve as a promising therapeutic target, particularly for recurrent esophageal tumors.
authors.affiliation: Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China. yqsIII@yahoo.com.cn
authors.forename: Qing-Shan
authors.initials: QS
authors.lastname: Yang
authors.forename: Jin-Long
authors.initials: JL
authors.lastname: Gu
authors.forename: Li-Qing
authors.initials: LQ
authors.lastname: Du
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Jia
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Qin
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Fei-Yue
authors.initials: FY
authors.lastname: Fan
mesh_terms: D034961:Antigens, Nuclear / Q000235:genetics / Q000378:metabolism*; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects*; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects* / Q000528:radiation effects*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004938:Esophageal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D005720:Gamma Rays; D020868:Gene Silencing; D006801:Humans; D000072200:Ku Autoantigen; D016685:Mitomycin / Q000008:administration & dosage*; D034741:RNA, Small Interfering / Q000235:genetics; D011836:Radiation Tolerance / Q000187:drug effects / Q000528:radiation effects
chemical_list: D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; D034741:RNA, Small Interfering; D016685:Mitomycin; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen