title: MicroR-545 enhanced radiosensitivity via suppressing Ku70 expression in Lewis lung carcinoma xenograft model.
abstract: OBJECTIVE
  Radiotherapy is an important therapeutic method for lung cancer. However, in clinical situations, cellular resistance to radiotherapy is a significant component of tumor treatment failure. Thus, clarification in cellular mechanism underlying radiosensitivity of cancer cell is urgently needed. In this study, we established a radiation model of Lewis lung carcinoma in C57BL/6 mice and investigated the possible signaling molecule involved in this process.
  
  
  METHODS
  C57BL/6 mice were subcutaneously transplanted with Lewis lung carcinoma cells and locally irradiated followed by measurement in tumor volume. Levels of miR-545 and Ku70 mRNA expression were determined by using Quantitative Real-Time PCR. Expression of Ku70 was determined by using western blot assay. Cell viability was analyzed by MTT assay. Cell apoptosis was examined by using TUNEL assay.
  
  
  RESULTS
  In mice bearing Lewis lung carcinoma tumor, local radiotherapy suppressed tumor growth as well as enhanced expression of miR-545 and downregulated Ku70 level. Inhibition of miR-545 expression reduced radiosensitivity of Lewis tumor. In vitro Lewis lung carcinoma cells experiment, we observed that miR-545 regulated Ku70 expression by targeting Ku70 3'UTR and this process was involved in radiotherapy. This was demonstrated by result of cell proliferation assay in which irradiation reduced apoptosis of cells was mediated by miR-545 inactivation which was reversed by Ku70 silence.
  
  
  CONCLUSIONS
  miR-545 increased radiosensitivity of Lewis lung carcinoma via inhibiting Ku70 expression.
authors.affiliation: Department of Radiotherapy, Nanjing Chest Hospital Affiliated to Southeast University, Guangzhou Road, No215, P.R, Nanjing, Jiangsu 210029 China.
authors.forename: Chen
authors.initials: C
authors.lastname: Liao
authors.affiliation: Department of Radiotherapy, Nanjing Chest Hospital Affiliated to Southeast University, Guangzhou Road, No215, P.R, Nanjing, Jiangsu 210029 China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
authors.affiliation: Department of Radiotherapy, Nanjing Chest Hospital Affiliated to Southeast University, Guangzhou Road, No215, P.R, Nanjing, Jiangsu 210029 China.
authors.forename: Nuo
authors.initials: N
authors.lastname: Zhu
authors.affiliation: Department of Radiotherapy, Nanjing Chest Hospital Affiliated to Southeast University, Guangzhou Road, No215, P.R, Nanjing, Jiangsu 210029 China.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Radiotherapy, Nanjing Chest Hospital Affiliated to Southeast University, Guangzhou Road, No215, P.R, Nanjing, Jiangsu 210029 China.
authors.forename: Jiu
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Radiotherapy, Nanjing Chest Hospital Affiliated to Southeast University, Guangzhou Road, No215, P.R, Nanjing, Jiangsu 210029 China.
authors.forename: Yanhu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Radiotherapy, Nanjing Chest Hospital Affiliated to Southeast University, Guangzhou Road, No215, P.R, Nanjing, Jiangsu 210029 China.
authors.forename: Mei
authors.initials: M
authors.lastname: Hong
keywords: C57BL/6 mice; Ku70; Lewis lung carcinoma cells; Radiotherapy; miR-545