Anti-miRNA-221 sensitizes human colorectal carcinoma cells to radiation by upregulating PTEN  

作　　者：Qi Xue Kai Sun Hai-Jun Deng Shang-Tong Lei Jing-Qing Dong Guo-Xin Li 

机构地区：[1]Department of General Surgery, Nanfang Hospital of Southern Medical University

出　　处：《World Journal of Gastroenterology》2013年第48期9307-9317,共11页世界胃肠病学杂志（英文版）

基　　金：Supported by National Natural Science Foundation of China,No.81101896;the National Research Foundation for Doctoral Program of Higher Education of China,No.20124433110010

摘　　要：AIM:To investigate the regulative effect of miRNA(miR)-221 on colorectal carcinoma(CRC)cell radiosensitivity and the underlying mechanisms.METHODS:A human CRC-derived cell line was cultured conventionally and exposed to different doses of X-rays(0,2,4,6 and 8 Gy).The total RNA and protein of the cells were extracted 24 h after irradiation,and the alteration of miR-221 and phosphatase and tensin homolog deleted on chromosome 10(PTEN)gene mRNA expression was detected by real-time reverse transcriptase polymerase chain reaction(PCR).The protein alteration of PTEN in the cells was detected by Western blotting.Caco2 cells were pretreated with or without anti-PTEN-siRNA prior to the addition of premiR-221 or anti-miR-221 using Lipofectamine 2000.Colony formation assay and flow cytometry analysis were used to measure the surviving cell fraction and the sensitizing enhancement ratio after irradiation.Ad-ditionally,PTEN 3′-untranslated region fragment was PCR amplified and inserted into a luciferase reporter plasmid.The luciferase reporter plasmid construct was then transfected into CRC cells together with premiR-221 or anti-miR-221,and the luciferase activity in the transfected cells was detected.RESULTS:The X-ray radiation dose had a significant effect on the expression of miR-221 and PTEN protein in human Caco2 cells in a dose-dependent manner.The miR-221 expression level improved gradually with the increase in irradiation dose,while the PTEN protein expression level reduced gradually.miR-221 expression was significantly reduced in the anti-miR-221 group compared with the pre-miR-221 and negative control groups(P<0.01).Anti-miR-221 upregulated expression of PTEN protein and enhanced the radiosensitivity of Caco2 cells(P<0.01).Moreover,the inhibitory effect was dramatically abolished by pretreatment with anti-PTEN-siRNA,suggesting that the enhancement of radiosensitivity was indeed mediated by PTEN.A significant increase of luciferase activity was detected in CRC cells that were cotransfected with the luciferase reporAIM: To investigate the regulative effect of miRNA (miR)-221 on colorectal carcinoma (CRC) cell radiosensitivity and the underlying mechanisms.

关 键 词：COLORECTAL carcinoma MIR-221 PHOSPHATASE and TENSIN HOMOLOG deleted on chromosome 10 RADIOSENSITIVITY 

分 类 号：R735.3[医药卫生—肿瘤]