下调miR-155通过抑制HIF-1α/VEGF通路增强人结直肠癌细胞的放射敏感性

Down-regulation of miR-155 enhances radiosensitivity of human colorectal cancer cells by inhibiting HIF-1α/VEGF pathway

目的:探讨miR-155对结直肠癌细胞SW620放射敏感性的影响及其特异性的作用机制。方法:将anti-miRNA-155和anti-miRNA-155 NC转染至结直肠癌细胞SW620,分别标记为anti-miR-155组和NC组;利用qRT-PCR检测细胞转染效率;对转染后的细胞进行电离辐射;经过电离辐射后采用克隆形成实验评估SW620细胞放射生物学参数;采用CCK8、细胞划痕、Transwell侵袭和流式细胞术分别检测SW620的增殖、迁移、侵袭和凋亡情况;双荧光素酶报告试验检测HIF-1α和miR-155的靶向关系;Western blotting检测HIF-1α、VEGF的表达水平。结果:转染anti-miRNA-155后,miRNA-155的表达量明显减少。与NC组比较,anti-miR-155组中SW620细胞的放射敏感性显著增加(P<0.05)。抑制miR-155的表达显著降低结直肠癌细胞增殖、迁移和侵袭的能力(P<0.05),而细胞凋亡率明显增加(P<0.05)。miRNA-155靶向调控HIF-1α。下调miRNA-155显著降低HIF-1α和VEGF的蛋白表达水平。结论:miR-155的下调能够增加结直肠癌细胞的放射敏感性,其作用机制可能是通过抑制HIF-1α/VEGF信号通路来实现。

Objective:To clarify the effect and the specific mechanism of miR-155 on the radio sensitivity of colorectal cancer cell line SW620.Methods:Colorectal cancer cell line SW620 was transfected with anti-miR-155(anti-miR-155 group)or anti-miR-155 NC(NC group),respectively.The transfection efficacy was measured by qRT-PCR.SW620 cells were subjected to ionizing radiation after transfection,and plate colony formation assay was performed to detect radiobiological parameters.CCK8 assay was used to measure the cell viability of colorectal cancer cells.The migration and invasion abilitiesof SW620 cells were detected by wound healing assay and transwell assay.Apoptosis was determined by flow cytometry.The dual luciferase reporter assay was hired to detect the targeting relationship between HIF-1αand miR-155.Western blot was used to assess the expression level of HIF-1αand VEGF.Results:After transfection with anti-miR-155,the expression of miR-155 was significantly decreased.Compared with NC group,the radiosensitivity of SW620 cells in the anti-miR-155 group was significantly increased(P<0.05).The suppression of miR-155 inhibited SW620 cells viability,migration,and invasion,while enhanced cell apoptosis(P<0.05).miR-155 targeted HIF-1α.Down-regulation of miR-155 significantly reduced the protein expression levels of HIF-1αand VEGF(P<0.05).Conclusion:Down-regulation of miR-155 increases the radiosensitivity of human colorectal cancer cell line SW620,and the mechanism may be related to suppression of HIF-1α/VEGF signaling pathway.