Effect of BMI-1 on radiosensitization of esophageal carcino-ma cells after silencing of BMI-1 gene
Yang Xingxiao,Ma Ming,Song Heng,Liu Zhikun,Zhu Shuchai
Department of Infection management (Yang XX),Department of Laboratory (Ma M),Department of Radiation Oncology (Song H,Liu ZK,Zhu SC),Fourth Affiliated Hospital of Hebei Medical University,Shijiazhuang 050011,China
Abstract： Objective To investigate the effects of BMI-1 expression inhibition by RNA interference on the radiosensitivity of esophageal cancer TE-13 cells and its mechanism. Methods The siRNA based on the sequence of BMI-1 mRNA was synthesized to transfect cultured TE-13 cells as BMI-1 siRNA group, a negative one was synthesized to transfect cultured TE-13 cells as negative control group (NC group), and untransfected TE-13 cells were named as control group. The expression of the BMI-1 mRNA and protein in TE-13 cells was measured by quantitative real-time PCR and Western blot, respectively. The cell proliferation and the radiosensitivity of TE-13 cells were measured by MTS and colony-forming assay, respectively. Flow cytometry was used to analyze cell cycle and apoptosis. The expression of BCL-2 and BAX in TE-13 cells was measured by Western blot. Comparison between groups was made by analysis of variance. Results The BMI-1 siRNA group had significantly lower expression of BMI-1 mRNA and protein than the control group and the NC group (P=0.000,0.000). The proliferation of TE-13 cells in the BMI-1 siRNA group decreased significantly after irradiation (P=0.031). The colony-forming assay showed that the BMI-1 siRNA group had a significantly higher radiosensitivity than the control group and the NC group (P=0.000). After irradiation, the BMI-1 siRNA group had a significantly lower percentage of cells in G2/M phase than the control group and the NC group (P=0.000,0.000). The BMI-1 siRNA group had a significantly increased apoptosis rate (P=0.000,0.000),significantly reduced expression of BCL-2(P=0.000,0.000), and significantly increased expression of BAX after irradiation (P=0.000,0.000). Conclusions BMI-1 siRNA can inhibit the expression of BMI-1 gene in esophageal cancer TE-13 cells, eliminate the cell cycle arrest in G2/M phase, induce cell apoptosis after ionizing irradiation in vitro, and increase the radiosensitivity, which may be related to the regulation of the expression of BCL-2 and BAX.
Yang Xingxiao,Ma Ming,Song Heng et al. Effect of BMI-1 on radiosensitization of esophageal carcino-ma cells after silencing of BMI-1 gene[J]. Chinese Journal of Radiation Oncology, 2017, 26(6): 671-676.
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2017, Vol. 26 
