Ding Lei, Zhang Shanyong, Xu Mu, Zhang Renwen, Sui Pengcheng, Yang Qing
Department of Pathogenobiology, College of Basic Medical Sciences, Jilin University, 126 Xinmin Street, Changchun, 130021, Jilin Province, China.
Department of Orthopedics, The Second Hospital, Jilin University, Changchun, Jilin, China.
J Exp Clin Cancer Res. 2017 Mar 21;36(1):45. doi: 10.1186/s13046-017-0516-2.
Accumulating evidence indicates that microRNA-27a (miR-27a) is involved in carcinogenesis and tumor progression. However, the exact function and molecular mechanism of miR-27a in gastric cancer remain unclear.
Quantitative real-time PCR (qRT-PCR) was used to quantify the expression of miR-27a and its target gene. The function of miR-27a in gastric cancer was investigated through in vitro and in vivo assays (MTT assay, colony formation assay, flow cytometry assay, wound healing assay, migration and invasion assay, immunohistochemistry (IHC), immunofluorescence (IF) and Western blot). A luciferase reporter assay was conducted to confirm the target gene of miR-27a.
We found that miR-27a was commonly overexpressed in gastric cancer and high expression of miR-27a was associated with distant metastasis, lymph node metastasis, advanced T stage and advanced clinical stage. Functional assays demonstrated that overexpression of miR-27a in AGS cells accelerated cell proliferation, migration and invasion and suppressed apoptosis. Meanwhile, opposite results were observed in SGC-7901 cells when miR-27a was suppressed. Consistently, down-regulation of miR-27a inhibited the growth and metastasis of engrafted tumors in vivo. Furthermore, we found PH domain and leucine-rich repeat protein phosphatase 2 (PHLPP2) to be a new target of miR-27a, and downregulation of PHLPP2 could rescue the effect of anti-miR-27a in gastric cancer cells. In addition, miR-27a-mediated suppression of PHLPP2 led to stimulation of the AKT/GSK3β pathway.
Our data suggest that miR-27a functions as a crucial oncogenic miRNA in gastric cancer. It can promote proliferation and metastasis of tumor cells by suppressing PHLPP2 and activating the AKT/GSK3β pathway. Therefore, miR-27a is a potential novel therapeutic target in gastric cancer treatment.
越来越多的证据表明，微小RNA-27a（miR-27a）参与肿瘤发生和肿瘤进展。然而，miR-27a在胃癌中的确切功能和分子机制仍不清楚。
采用定量实时聚合酶链反应（qRT-PCR）对miR-27a及其靶基因的表达进行定量。通过体外和体内实验（MTT实验、集落形成实验、流式细胞术实验、伤口愈合实验、迁移和侵袭实验、免疫组织化学（IHC）、免疫荧光（IF）和蛋白质免疫印迹法）研究miR-27a在胃癌中的作用。进行荧光素酶报告基因实验以确认miR-27a的靶基因。
我们发现miR-27a在胃癌中普遍高表达，且miR-27a的高表达与远处转移、淋巴结转移、T分期较晚及临床分期较晚相关。功能实验表明，在AGS细胞中过表达miR-27a可加速细胞增殖、迁移和侵袭并抑制细胞凋亡。同时，当miR-27a被抑制时，在SGC-7901细胞中观察到相反的结果。同样，下调miR-27a可抑制体内移植瘤的生长和转移。此外，我们发现PH结构域和富含亮氨酸重复序列的蛋白磷酸酶2（PHLPP2）是miR-27a的一个新靶标，下调PHLPP2可挽救抗miR-27a对胃癌细胞的作用。此外，miR-27a介导的对PHLPP2的抑制导致AKT/GSK3β信号通路的激活。
我们的数据表明，miR-27a在胃癌中作为一种关键的致癌微小RNA发挥作用。它可通过抑制PHLPP2和激活AKT/GSK3β信号通路促进肿瘤细胞的增殖和转移。因此，miR-27a是胃癌治疗中一个潜在的新型治疗靶点。
