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目的:探讨miR-143-3p靶向调控Kirsten鼠肉瘤病毒癌基因(KRAS)介导丝裂原活化蛋白激酶(MAPK)/细胞外调节蛋白激酶(ERK)信号通路对胃癌细胞增殖和侵袭的作用机制。方法:双荧光素酶报告基因实验验证miR-143-3p与KRAS基因的靶向关系。将购自上海中国科学院的胃癌细胞株转染分组，将筛选人胃癌细胞株按照不同转染构建分为6组，miR-143-3p mimic阴性对照(negative control，NC)组、miR-143-3p Inhibitor NC组、miR-143-3p mimic组、miR-143-3p Inhibitor组、si-KRAS NC组、si-KRAS组、miR-143-3p Inhibitor＋si-KRAS组。实时定量聚合酶链式反应(RT-qPCR)和蛋白质免疫印迹(Western blot)法检测转染后各组细胞相关因子的mRNA和蛋白的表达情况。细胞计数试剂盒-8(CCK-8)法及Transwell小室法检测胃癌细胞增殖及侵袭能力的变化。组间比较采用n t检验。n 结果:双荧光素酶报告基因实验证明KRAS是miR-143-3p靶基因。miR-143-3p mimic组的miR-143-3p表达量高于NC组(n t＝17.630，n P<0.05)，在miR-143-3p inhibitor组中表达量低于NC组(n t＝20.780，n P<0.05)，差异有统计学意义。在miR-143-3p mimic组(mRNA：KRAS为1.00±0.05比0.33±0.03，n t＝19.900；ERK为1.00±0.05比0.27±0.01，n t＝24.800；JNK为1.00±0.06比0.60±0.04，n t＝9.608；E-cadherin为1.00±0.04比1.69±0.06，n t＝16.570；N-cadherin为1.00±0.03比0.54±0.04，n t＝15.930；Snail为1.00±0.05比0.39±0.03，n t＝18.120；蛋白：KRAS为0.54±0.04比0.23±0.01，n t＝13.020；ERK为0.63±0.04比0.30±0.01，n t＝13.860；JNK为0.71±0.05比0.33±0.02，n t＝12.220；E-cadherin为0.85±0.05比1.20±0.06，n t＝7.762；N-cadherin为0.44±0.03比0.36±0.02，n t＝3.843；Snail为0.50±0.03比0.25±0.01，n t＝13.690)中KRAS、p-ERK/ERK、p-JNK/JNK、N-cadherin和Snail的mRNA和蛋白表达量低于NC组，而E-cadherin的mRNA和蛋白表达量高于NC组，细胞增殖(miR-143-3p mimic组：48 h为1.124±0.060比0.978±0.050，n t＝3.238；72 h为2.545±0.120比2.122±0.110，n t＝4.501；si-KRAS组：48 h为1.140±0.060比1.020±0.060，n t＝2.449；72 h为2.500±0.120比2.070±0.100，n t＝4.768)及侵袭能力(miR-143-3p mimic组：210.00±10.00比110.00±7.00，n t＝14.190；si-KRAS组：215.00±12.00比100.00±6.00，n t＝14.850)低于NC组，差异均有统计学意义(n P值均<0.05)；而miR-143-3p Inhibitor组前述趋势逆转(n P值均<0.05)，差异有统计学意义。n 结论:miR-143-3p抑制靶向KRAS基因表达，阻断MAPK/ERK信号通路的激活，从而抑制人胃癌增殖侵袭，并调控上皮间质转化进程。“,”Objective:To investigate the effect of miR-143-3p on the proliferation and invasion of gastric cancer cells by targeting kirsten rat sarcoma (KRAS) gene and mediating mitogen-activated protein kinase (MAPK)/extracellular regulated protein kinase (ERK) signaling pathway.Methods:Dual luciferase reporter gene assay was used to verify the targeting relationship between miR-143-3p and KRAS gene. Gastric cancer cells purchased from Chinese Academy of Sciences in Shanghai were transfected into different groups. Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) and Western blotting were used to detect the mRNA and protein expressions of related indexes. Cell counting kit-8 (CCK-8) and Transwell assays were used to examine the proliferation and invasion of gastric cancer cells.Results:Dual luciferase reporter gene assay verified that KRAS was the target gene of miR-143-3p. After cell grouping and transfection, as compared with corresponding negative control (NC) group, miR-143-3pmimic group showed increased miR-143-3p expression (n t=17.630), which was decreased in miR-143-3p inhibitor group (n t=20.780; all n P<0.05). In miR-143-3p mimic group and si-KRAS group, there were increased mRNA (for miR-143-3p mimic group, KRAS: 1.00±0.05 vs. 0.33±0.03,n t=19.900; ERK: 1.00±0.05 vs. 0.27±0.01, n t=24.800; JNK: 1.00±0.06 vs. 0.60±0.04, n t=9.608; E-cadherin: 1.00±0.04 vs. 1.69±0.06, n t=16.570; N-cadherin: 1.00±0.03 vs. 0.54±0.04, n t=15.930; Snail: 1.00±0.05 vs. 0.39±0.03, n t=18.120. Expression levels of KRAS, p-ERK/ERK, p-JNK/JNK, N-cadherin and Snail, while decreased E-cadherin mRNA and protein expression levels, decreased cell proliferation (formiR-143-3p mimic group at 48 h: 1.124±0.060 vs. 0.978±0.050, n t=3.238; at 72 h: 2.545±0.120 vs. 2.122±0.110, n t=4.501. for si-KRAS group at 48 h: 1.140±0.060 vs. 1.020±0.060, n t=2.449; at 72 h: 2.500±0.120 vs. 2.070±0.100, n t=4.768) and invasion (for miR-143-3p mimic group: 210.00±10.00 vs. 110.00±7.00, n t=14.190; for si-KRAS group: 215.00±12.00 vs. 100.00±6.00, n t=14.850), and the differences were statistically significant (all n P<0.05). While miR-143-3p inhibitor group had the opposite trends mentioned above (alln P<0.05).n Conclusion:MiR-143-3p inhibits the expression of targeted KRAS gene and blocks the activation of MAPK/ERK signaling pathway, thus inhibiting the proliferation and invasion of human gastric cancer cells and regulating epithelial mesenchymal transition process.