Li Chen, Xu Binwu, Miu Xinxin, Deng Zhongbo, Liao Hang, Hao Liang
Department of Orthopedic Surgery, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006, P.R. China.
Exp Ther Med. 2018 Jan;15(1):1036-1040. doi: 10.3892/etm.2017.5477. Epub 2017 Nov 10.
The present study aimed to investigate the expression of micro (mi)RNA-21 in osteosarcoma cells, and its role in inhibiting the invasion and metastasis of osteosarcoma. Human osteosarcoma MG-63 cells and osteoblast hFOB1.19 cells were used to compare the expression of miRNA-21 using reverse transcription-quantitative polymerase chain reaction analysis. A miRNA-21 mimic or inhibitor were transfected into the MG-63 cells to upregulate and downregulate the expression of miRNA-21, respectively. The present study investigated the proliferation and invasion of transfected MG-63 cells using MTT and Transwell assays. Western blot analyses were used to investigate the regulation of important proteins in the phosphatase and tensin homolog/phosphoinositide 3-kinase/RAC-α serine/threonine-protein kinase (PTEN/PI3K/AKT) signaling pathway. Compared with hFOB1.19 cells, miRNA-21 expression was significantly upregulated in the MG-63 cells (P<0.01), which lead to increased proliferation. Downregulating miRNA-21 expression reduced the proliferation of MG-63 cells compared with hFOB1.19 cells. Invasion assays and western blot analyses revealed that the overexpression of miRNA-21 significantly enhanced the invasion ability of MG-63 cells and the expression of phosphorylated (p-)AKT, while downregulation of miRNA-21 expression reduced the protein level of AKT and p-AKT. In the MG-63 cells, miRNA-21 upregulation significantly inhibited the protein level of PTEN, resulting in significantly increased AKT and PI3K protein levels (P<0.01). In conclusion, the results of the present study indicate that the expression of miRNA-21, PI3K and AKT is increased in the osteosarcoma cell line MG-63, which results in reduced expression of PTEN and increased expression of proteins in the PI3K/AKT signaling pathway, and thus increases the aggressiveness of osteosarcoma cells.
本研究旨在探讨微小（mi）RNA-21在骨肉瘤细胞中的表达及其在抑制骨肉瘤侵袭和转移中的作用。采用人骨肉瘤MG-63细胞和成骨细胞hFOB1.19细胞，通过逆转录-定量聚合酶链反应分析比较miRNA-21的表达。将miRNA-21模拟物或抑制剂转染到MG-63细胞中，分别上调和下调miRNA-21的表达。本研究采用MTT和Transwell实验研究转染后MG-63细胞的增殖和侵袭情况。采用蛋白质印迹分析研究磷酸酶和张力蛋白同源物/磷脂酰肌醇3-激酶/RAC-α丝氨酸/苏氨酸蛋白激酶（PTEN/PI3K/AKT）信号通路中重要蛋白的调控情况。与hFOB1.19细胞相比，MG-63细胞中miRNA-21表达显著上调（P<0.01），导致增殖增加。与hFOB1.19细胞相比，下调miRNA-21表达降低了MG-63细胞的增殖。侵袭实验和蛋白质印迹分析显示，miRNA-21的过表达显著增强了MG-63细胞的侵袭能力以及磷酸化（p-）AKT的表达，而miRNA-21表达下调降低了AKT和p-AKT的蛋白水平。在MG-63细胞中，miRNA-21上调显著抑制了PTEN的蛋白水平，导致AKT和PI3K蛋白水平显著增加（P<0.01）。总之，本研究结果表明，骨肉瘤细胞系MG-63中miRNA-21、PI3K和AKT的表达增加，导致PTEN表达降低，PI3K/AKT信号通路中蛋白表达增加，从而增加了骨肉瘤细胞的侵袭性。
