miR-155的下调通过直接靶向TWIST2促进胃癌细胞的侵袭和转移

Down-regulation of MiR-155 Promotes Invasion and Metastasis of Gastric Cancer Cells by Directly Targeting TWIST2

目的探讨miR-155的下调通过直接靶向TWIST2促进胃癌细胞的侵袭和转移行为及机制。方法 qPCR检测miR-155在胃癌组织和细胞株中的表达情况并分析miR-155表达和胃癌患者临床病理学参数之间的关系;双荧光素酶实验检测miR-155和Twist2之间的关系并分析miR-155对胃癌细胞株成瘤能力的影响。结果胃癌组织中miR-155的表达显著高于癌旁正常组织[(5.62±0.39)vs(1.62±0.16),P<0.05];不同胃癌细胞株中,MGC-803细胞株中miR-155的表达水平显著高于其他细胞株[(5.83±0.49)vs(1.62±0.16)vs(1.26±0.21)vs(2.03±0.18)vs(2.21±0.19),P<0.05];分期越高,miR-155在胃癌组织中表达越高,而在有淋巴结转移的患者中miR-155的表达也相对较高;抑制miR-155表达后,野生型Twist2的荧光素酶活性受到明显抑制,而对突变型Twist2的荧光素酶活性影响不大,同时抑制miR-155表达后,Twist2的蛋白表达水平也显著降低;抑制miR-155后胃癌细胞增殖转移能力减弱;同时成瘤后肿瘤总体体积相应减小,质量相应降低[体积(3.64±0.51)cm^3vs(1.29±0.24)cm^3;质量(3.82±0.49)g vs(1.09±0.21)g]。结论 miR-155的下调通过直接靶向TWIST2促进胃癌细胞的侵袭和转移行为。

Objective To investigate how the down-regulation of miR-155 by directly targeting TWIST2 promotes the invasion and metastasis of gastric cancer cells.Methods qPCR was used to detect the expression of miR-155 in gastric cancer tissues and cell lines. The relationships between miR-155 expression and clinicopathological parameters of gastric cancer patients were analyzed. The dual luciferase assay was used to detect the relationships between miR-155 and Twist2 and to study the effect of miR-155 on the tumorigenicity of gastric cancer cell lines. Results The expression of miR-155 in gastric cancer tissues was significantly higher than that in adjacent normal tissues [（ 5.62±0.39） vs（ 1.62±0.16）,P〈0.05].Among different gastric cancer cell lines,the expression of miR-155 in MGC-803 cell line was significantly higher than in other cell lines [（ 5.83± 0.49） vs（ 1.62±0.16） vs（ 1.26±0.21） vs（ 2.03±0.18） vs（ 2.21±0.19）,P〈0.05]. The higher the stage,the higher the expression of miR-155 in gastric cancer tissues,and the higher the expression of miR-155 in patients with lymph node metastasis. After inhibition of the expression of miR-155,the luciferase activity of wild-type Twist2 was significantly inhibited,but the luciferase activity of the mutant Twist2 was hardly affected. At the same time,after inhibiting the expression of miR-155,the protein expression level of Twist2 also decreased significantly. Inhibition of miR-155 after gastric cancer cell proliferation and metastasis was weakened while the overall volume of tumor after tumor reduction was correspondingly reduced,and the quality became lower accordingly [（ 3.64±0.51） cm^3 vs（ 1.29± 0.24） cm^3; mass（ 3.82±0.49） g vs（ 1.09±0.21） g]. Conclusion Down-regulation of miR-155 promotes invasion and metastasis of gastric cancer cells by directly targeting TWIST2.