Zhang Ying, Li Chang-Feng, Ma Lian-Jun, Ding Meng, Zhang Bin
Endoscopy Center, China-Japan Union Hospital, Jilin University, Changchun, Jilin 130033, P.R. China.
Int J Oncol. 2016 Sep;49(3):1068-80. doi: 10.3892/ijo.2016.3581. Epub 2016 Jun 16.
Growing evidence suggests that microRNA plays an essential role in the development and metastasis of many tumors, including gastric cancer. Aberrant miR-224 expression has been indicated in tumor growth, the mechanism of miR-224 promoting the proliferation and metastatic ability for gastric cancer remains unclear. Accumulating evidence reports that mTOR signal pathway plays an important role in the cellular process, such as apoptosis, cell growth and proliferation. The goal of the present study was to identify whether miR-224 could inhibit the growth, migration, invasion, proliferation and metastasis of gastric cancer through targeting mTOR expression. Real-time PCR (RT-PCR) was used to quantify miR-224 expression in vitro and in vivo experiments. Luciferase reporter assays were performed to confirm the activity of mTOR pathway, and immunofluorescence staining assay was conducted to observe apoptosis and cell proliferation ability. Bioinformatics as well as cell luciferase function studies distinguished the direct modulation of miR-224 on the 3'-UTR of the mTOR, which leads to the inactivation of apoptosis signaling and the activation of cell proliferation. In addition, inhibition of miR-224 significantly reduced the expression of mTOR and improved caspase-9/3 expression while decreased cyclin D1/2 levels, attenuating gastric cancer cell proliferation. Therefore, the present study revealed the mechanistic links between miR-224 and mTOR in the pathogenesis of gastric cancer through modulation of caspase-9/3 and cyclin D1/2. In addition, targeting miR-224 could serve as a novel strategy for future gastric cancer therapy.
越来越多的证据表明，微小RNA在包括胃癌在内的许多肿瘤的发生和转移中起着至关重要的作用。已有研究表明miR-224表达异常与肿瘤生长有关，但其促进胃癌增殖和转移能力的机制仍不清楚。越来越多的证据表明，mTOR信号通路在细胞凋亡、细胞生长和增殖等细胞过程中发挥重要作用。本研究的目的是确定miR-224是否可通过靶向mTOR表达来抑制胃癌的生长、迁移、侵袭、增殖和转移。在体外和体内实验中，采用实时荧光定量PCR（RT-PCR）来定量miR-224的表达。进行荧光素酶报告基因检测以确认mTOR通路的活性，并进行免疫荧光染色检测以观察细胞凋亡和增殖能力。生物信息学以及细胞荧光素酶功能研究表明miR-224可直接调控mTOR的3'-UTR，从而导致凋亡信号失活和细胞增殖激活。此外，抑制miR-224可显著降低mTOR的表达，提高caspase-9/3的表达，同时降低细胞周期蛋白D1/2的水平，从而减弱胃癌细胞的增殖。因此，本研究揭示了miR-224和mTOR在胃癌发病机制中通过调节caspase-9/3和细胞周期蛋白D1/2的机制联系。此外，靶向miR-224可能成为未来胃癌治疗的新策略。
