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c-Myc通过调控ATP结合盒转运蛋白表达对CD133+肠癌干细胞耐药性的影响

张欢乐, 王萍, 陆妙珍, 张三典

宁波市医疗中心李惠利医院肿瘤放射治疗科，宁波 315000；宁波大学医学院生物化学与分子生物学系，宁波 315000

摘要

本文旨在探讨c-Myc通过调控ATP结合盒(ATP-binding cassette, ABC)转运蛋白表达对CD133+肠癌干细胞耐药性的影响及机制。以人肠癌HT29细胞系为模型，通过流式细胞分选术获得CD133+肠癌干细胞，以核心基因c-Myc为靶点设计小干扰RNA (siRNA)，靶向抑制CD133+细胞中c-Myc基因表达；免疫印迹法检测c-Myc沉默后ABC转运蛋白家族成员(ABCG2、MDR-1和ABCB5)表达水平变化；药敏实验检测肠癌干细胞对化疗药物(5-FU或/和奥沙利铂)的耐药性。结果显示，CD133+细胞高表达核心基因c-Myc，siRNA显著抑制肠癌干细胞中c-Myc的表达水平；CD133+肠癌干细胞对化疗药物(5-FU或/和奥沙利铂)具有耐药性；siRNA通过抑制c-Myc下调CD133+肠癌干细胞ABC转运蛋白(ABCG2、MDR-1和ABCB5)的表达水平；靶向抑制c-Myc表达提高CD133+肠癌干细胞对化疗药物的敏感性(P < 0.05)。以上结果表明，c-Myc通过调控ABC转运蛋白表达水平参与肿瘤干细胞的耐药机理，靶向抑制c-Myc能提高CD133+肠癌干细胞对化疗药物的敏感性。

关键词： 肿瘤干细胞; c-Myc; ABC转运蛋白; 耐药性

分类号：R735.34

[c-Myc regulation of ATP-binding cassette transporter reverses chemoresistance in CD133+ colon cancer stem cells.] [Article in Chinese]

ZHANG Huan-Le, WANG Ping, LU Miao-Zhen, ZHANG San-Dian

Department of Radiotherapy, Lihuili Hospital of Ningbo Medical Center, Ningbo 315000, China； Department of Biochemistry, Ningbo University School of Medicine, Ningbo 315000, China

Abstract

The present study was aimed to explore the role of c-Myc gene regulation in maintaining the self-renewal and drug-resistant properties of colon cancer stem cells (CSCs) and the underlying mechanism. CD133+ cells were isolated by flow cytometry cell sorting from human HT29 cancer cells. A small interfering RNA (siRNA) against c-Myc was used, and the mRNA and protein expressions of c-Myc were investigated by real-time PCR and Western blotting, respectively. To evaluate the effect of c-Myc on the drug resistance of colon CSCs, CD133+ cells transfected with c-Myc-siRNA were exposed to 5-FU, oxaliplatin, or their combination. The expressions of ATP-binding cassette (ABC) transporters, including ABCG2, ABCB5 and MDR-1, were detected by Western blotting. The results showed that c-Myc was highly expressed in CD133+ colon CSCs, and the protein and mRNA expressions of c-Myc were effectively blocked by c-Myc siRNA. Furthermore, CD133+ cells showed significantly increased survival rate in chemotherapy treatment, compared with CD133− cells. c-Myc silencing sensitized CD133+ cells to chemotherapy-induced cytotoxicity and down-regulated the protein expression levels of ABCG2, MDR-1 and ABCB5. These results suggest c-Myc silencing may regulate the expressions of ABC transporters in colon CSCs, and enhance the sensitivity of CSCs to the chemotherapy.

Key words: cancer stem cell; c-Myc; ATP-binding cassette transporter; chemoresistance

收稿日期：2015-12-02　　录用日期：2016-01-24

通讯作者：张欢乐　　E-mail: zhl520@163.com

引用本文：

张欢乐, 王萍, 陆妙珍, 张三典. c-Myc通过调控ATP结合盒转运蛋白表达对CD133+肠癌干细胞耐药性的影响[J]. 生理学报 2016; 68 (2): 171-178.

ZHANG Huan-Le, WANG Ping, LU Miao-Zhen, ZHANG San-Dian. [c-Myc regulation of ATP-binding cassette transporter reverses chemoresistance in CD133+ colon cancer stem cells.] [Article in Chinese]. Acta Physiol Sin 2016; 68 (2): 171-178 (in Chinese with English abstract).