机构：[1]Departments of Radiation Oncology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China河北医科大学第四医院[2]Departments of Clinical Laboratory, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China河北医科大学第四医院[3]Departments of Research Centre, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China河北医科大学第四医院
B-cell-specific Moloney murine leukaemia virus integration site-1 (BMI-1) contributes to the growth of tumour cells post-irradiation (IR). The aim of the present study was to characterize the effects of BMI-1 on cell viability, radiosensitivity and its mechanisms of action in oesophageal squamous cell cancer (ESCC). Western blotting and immunohistochemistry were employed to evaluate the protein expression of BMI-1 in ESCC cells and specimens, respectively. Additionally, the protein expression levels of BMI-1, H2AK119ub and gamma H2AX in ESCC cells were detected following different doses of IR and at different times after IR. The protein expression levels of MDC1 and 53BP1 were also measured. Flow cytometry and MTT assays were used to determine cell cycle progression, apoptosis and cell viability. The phosphatidylinositol 3-kinase inhibitor LY294002 and the agonist IGF-1 were employed to suppress or induce the phosphorylation of Akt to determine whether BMI-1 induces radioresistance in ESCC cells via activation of the PI3K/Akt pathway. The expression of BMI-1 was higher in ESCC tissues and cells compared with that in normal oesophageal tissues and cells. In addition, BMI-1 was positively related to tumour size and lymph node metastases and negatively to the overall survival of ESCC patients. IR induced the expression of BMI-1, H2AK119ub and gamma H2AX in a dose-and time-dependent manner. BMI-1 knockdown lowered the expression of.H2AX, MDC1 and 53BP1, suppressed cell viability and increased radiosensitivity. G2/M phase arrest was eliminated; this was followed by an increased proportion of cells entering the G0/G1 phase after IR and BMI-1 knockdown via the upregulation of P16 and downregulation of cyclin D2 and cyclin-dependent kinase-4. Moreover, BMI-1 knockdown increased cell apoptosis, downregulated MCL-1 and p-Akt and upregulated Bax. Additionally, the inhibitory effect of the downregulation of p-Akt by LY294002 on tumour cell viability was identical to that of BMI-1 knockdown, while the kinase agonist IGF-1 reversed the effects of BMI-1 knockdown on cell viability and radiosensitivity. Taken together, BMI-1 knockdown induces radiosensitivity in ESCC and significantly inhibits cell viability, which may contribute to an increased proportion of cells in the G0/G1 phase and cell apoptosis via suppression of the PI3K/Akt signalling pathway.
基金：
National Natural
Science Foundation of China (no. 81372416), the Natural Science
Foundation of China of Hebei Province (no. H2017206170),
and the Medical Research Institute of Hebei Province
(nos. 20160183 and 20170154).
第一作者机构：[1]Departments of Radiation Oncology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China
通讯作者：
通讯机构：[1]Departments of Radiation Oncology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China[*1]Department of Radiation Oncology, The Fourth Hospital of Hebei Medical University, 12 Jiankang Road, Shijiazhuang, Hebei 050011, P.R. China
推荐引用方式(GB/T 7714)：
Yang Xing-Xiao,Ma Ming,Sang Mei-Xiang,et al.BMI-1 suppression increases the radiosensitivity of oesophageal carcinoma via the PI3K/Akt signaling pathway[J].ONCOLOGY REPORTS.2018,39(2):667-678.doi:10.3892/or.2017.6136.
APA：
Yang, Xing-Xiao,Ma, Ming,Sang, Mei-Xiang,Zhang, Xue-Yuan,Liu, Zhi-Kun...&Zhu, Shu-Chai.(2018).BMI-1 suppression increases the radiosensitivity of oesophageal carcinoma via the PI3K/Akt signaling pathway.ONCOLOGY REPORTS,39,(2)
MLA：
Yang, Xing-Xiao,et al."BMI-1 suppression increases the radiosensitivity of oesophageal carcinoma via the PI3K/Akt signaling pathway".ONCOLOGY REPORTS 39..2(2018):667-678
