title: Upregulation of miR-195 enhances the radiosensitivity of breast cancer cells through the inhibition of BCL-2.
abstract: OBJECTIVE
  To investigate the effect of miR-195 overexpression on radiosensitivity and the relevant molecular mechanisms in breast cancer.
  
  
  METHODS
  miR-195 mimics were transfected to breast cancer cell line MCF-7 by gene transfection; miR-195 expression level in cells was determined by real-time quantitative PCR. Cellular viability was observed by colony formation assay after the cells were irradiated with X-ray. Apoptosis was detected by annexin V/propidium iodide (PI) staining. Protein expression was evaluated by Western blot assay.
  
  
  RESULTS
  After miR-195 mimics were transfected, miR-195 expression in breast cancer cells was significantly upregulated (P < 0.05). miR-195 overexpression significantly enhanced the response to radiation of MCF-7 cells with a decrease in colony survival at individual doses of X-ray (P < 0.05). After the cells were irradiated with 5 Gy, apoptotic rate was significantly increased in miR-195-overexpressed group with a rate of 18.13% ± 1.57%; moreover, BCL-2 protein expression was significantly downregulated (P < 0.05).
  
  
  CONCLUSIONS
  Exogenetic miR-195 expression could significantly enhance the radiosensitivity of human breast cancer cells; this finding may be attributed to BCL-2 downregulation to promote radiation-induced apoptosis.
authors: Department of Thyroid and Breast Surgery, General Hospital of Jinan Military Command Jinan, China.
authors: Jian
authors: J
authors: Zhu
authors: Department of Radiation Oncology, The Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province Kunming, China.
authors: Qing
authors: Q
authors: Ye
authors: Department of Radiation Oncology, The Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province Kunming, China.
authors: Li
authors: L
authors: Chang
authors: Department of Radiation Oncology, The Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province Kunming, China.
authors: Wei
authors: W
authors: Xiong
authors: Department of Thyroid and Breast Surgery, General Hospital of Jinan Military Command Jinan, China.
authors: Qingqing
authors: Q
authors: He
authors: Department of Radiation Oncology, The Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan Province Kunming, China.
authors: Wenhui
authors: W
authors: Li
keywords: Breast cancer; apoptosis; miR-195; radiosensitivity