微小RNA-137调控乳腺癌细胞生物学行为的作用及机制研究

The regulatory effect of microRNA-137 on the biological behavior of breast cancer cells

目的探讨微小RNAU(miRNA)-137通过抑制靶基因磷酸酶和张力蛋白同源物(PTEN)调节磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B (AKT)信号通路对乳腺癌细胞生物学行为的调控作用。方法采用实时定量聚合酶链反应(qRT-PCR)检测不同组织和细胞中miRNA-137的表达水平,Transwell实验检测MCF-7和MDA-MB-231细胞的侵袭能力。通过生物信息学软件预测miRNA-137与靶基因的相互作用并进行验证,检测不同细胞和组织中PTEN mRNA及蛋白的表达水平,以及miRNA-137与PTEN通过PI3K/AKT通路对乳腺癌生物学行为的调控作用。结果乳腺癌组织中miRNA-137的表达水平明显高于癌旁正常组织(P<0.01)。发生远端转移乳腺癌组织中miRNA-137的表达水平明显高于未发生远端转移的乳腺癌组织(P <0.01)。MCF-7、MDA-MB-231细胞中miRNA-137的表达水平均明显高于MCF-10A细胞(P<0.01)。乳腺癌MDA-MB-231细胞的侵袭细胞数目明显高于MCF-7细胞(P <0.01)。生物信息学软件预测发现,PTEN mRNA 3TUTR的碱基存在与miRNA-137可能互补结合的位点。乳腺癌组织中PTEN mRNA及蛋白的表达水平均明显低于癌旁正常组织(P <0.01)。miRNA-137mimics转染组的OD值、S期细胞比值、侵袭细胞数目、迁移细胞数目均高于miRNA-NC组,细胞迁移距离长于miRNA-NC组,而miRNA-137 mimics+PTEN转染组的上述各指标均低于miRNA-137 mimics转染组(P <0.05)。miRNA-137 mimics转染组中PTEN、p-AKT 308、p-AKT 473蛋白的表达水平均高于miRNA-NC组(P <0.05);miRNA-137 mimics+PTEN转染组中PTEN、p-AKT 308、p-AKT 473蛋白的表达水平均低于miRNA-137 mimics转染组(P <0.05)。结论 miRNA-137通过抑制PTEN调节PI3K/AKT信号通路促进乳腺癌生物学行为可能会成为乳腺癌诊断及治疗新靶点。

Objective To investigate the regulatory effect of microRNA(miRNA)-137 on the biological behavior of breast cancer cells by inhibiting target gene phosphatase and tensin homolog(PTEN)to regulate phosphatidylinositol-3-kinase(PI3 K)/protein kinase B(AKT)signaling pathway.Method The expression level of miRNA-137 in different tissues and cells was detected by quantitative real-time polymerase chain reaction(qRT-PCR).The invasion of MCF-7 and MDA-MB-231 cells were detected by Transwell assay.The interaction between miRNA-137 and the target gene was predicted by bioinformatics software,and the result was then verified.The expression levels of PTEN mRNA and protein in different cells and tissues,as well as the regulatory effects of miRNA-137 and PTEN on the biological behavior of breast cancer through the PI3 K/AKT pathway were also tested.Result The expression level of miRNA-137 in breast cancer tissues was significantly higher than that in normal tissues adjacent to cancer(P<0.01).The expression level of miRNA-137 in breast cancer tissue with distant metastasis was also significantly higher than that in breast cancer tissue without distant metastasis(P<0.01).The expression level of miRNA-137 in MCF-7 and MDA-MB-231 cells was significantly higher than that in MCF-10 A cells(P<0.01).The number of invasive cells of breast cancer MDA-MB-231 cells was significantly higher than that of MCF-7 cells(P<0.01).Bioinformatics analysis predicted that the 3’UTR base of PTEN mRNA has an underlying locus that may complement miRNA-137.The expression levels of PTEN mRNA and protein in breast cancer tissues were significantly lower than those in normal tissues adjacent to cancer(P<0.01).The optical density(OD)value,S-phase cell ratio,cell invasion number,migrating cells number were higher than those of the miRNA-NC group,and cell migration distance of the miRNA-137 mimics transfection group was longer than those of the miRNA-NC group,while the forgoing indicators of the miRNA-137 mimics+PTEN transfection group were all lower than miRNA-137 mimics transfection group(P<0.05).The expression of PTEN,p-AKT 308,and p-AKT 473 proteins in the miRNA-137 mimics transfection group were higher than those in the miRNA-NC group(P<0.05),and the the expression of PTEN,p-AKT308 and p-AKT 473 in the miRNA-137 mimics+PTEN transfection group were lower than those in the miRNA-137 mimics transfection group(P<0.05).Conclusion The micRNA-137 regulates the PI3 K/AKT signaling pathway by inhibiting PTEN to promote the progressed biological behavior of breast cancer and may bring up a new target for breast cancer diagnosis and treatment.