Anti-microRNA-221通过上调PTEN蛋白表达增加结直肠癌细胞的放射增敏性

目的探讨下调microRNA-221（miR-221）表达对人结直肠癌细胞的放射敏感性的影响及其分子机制。方法常规培养人
结直肠癌Caco2细胞系，以脂质体转染反义miR-221（anti-miR-221）后，应用实时荧光定量PCR（Real-time Q-PCR）检测Caco2
细胞中miR-221和PTEN mRNA表达水平，应用Western-blot分析肿瘤细胞中PTEN蛋白表达变化；不同处理组的肿瘤细胞经
照射后，流式细胞仪检测各处理组细胞的死亡情况。结果Real-time Q-PCR显示转染anti-miR-221后miR-221的表达水平明显
下调（P<0.05），同时PTEN蛋白表达增高（P<0.05）；流式细胞仪检测可见anti-miR-221转染组及anti-miR-221转染联合照射组
死亡细胞比例均明显增多（P均<0.01），转染anti-miR-221可明显提高Caco2细胞的放射敏感性，且此效应能被PTEN-siRNA部
分但不完全阻断。结论Anti-miR-221可通过上调PTEN蛋白表达增加结直肠癌细胞的放射敏感性。

Anti-microRNA-221 enhances radiosensitivity of colorectal carcinoma cells by upregulating PTEN

Objective To investigate the effect of knocking-down microRNA-221 (miR-221) expression on the radiosensitivity of
human colorectal carcinoma cells. Methods Human colorectal carcinoma-derived cell line Caco2 was transfected with miR-221
antisense oligonucleotides (anti-miR-221) via Lipofectamine 2000. Real-time quantitative PCR was performed to detect the
expression of miR-221 and PTEN mRNA in Caco2 cells. The changes in the protein expression of PTEN in the transfected cells
were detected by Western blotting. The cell death after transfection and irradiation was detected by flow cytometry. Results
Transfection with anti-miR-221 caused a significant reduction in miR-221 expression (P<0.05) and up-regulated PTEN protein
expression (P<0.05) in Caco2 cells. The percentage of cell death was significantly increased in anti-miR-221 group and
anti-miR-221 with irradiation group (P<0.01). Anti-miR-221 significantly enhanced the radiosensitivity of Caco2 cells, which
was partially reversed by PTEN-siRNA. Conclusion Anti-miR-221 can enhance the radiosensitivity of colorectal carcinoma
cells by up-regulating the expression of PTEN.