Department of Medical Oncology, Qilu Hospital of Shandong University, Qingdao, China.
Eur Rev Med Pharmacol Sci. 2019 Feb;23(4):1459-1467. doi: 10.26355/eurrev_201902_17103.
This study aims to explore the biological function of maternally expressed gene 3 (MEG3) in liver cancer and the potential mechanism of phosphatidylinositide 3-kinases/protein kinase B (PI3K/AKT) pathway in regulating proliferation and invasion of hepatoma cells.
Quantitative Real-time polymerase chain reaction (qRT-PCR) was applied to examine the level of MEG3 in 72 pairs of liver cancer tissues and corresponding adjacent tissues. Expression levels of MEG3 and AP1G1 in hepatocellular carcinoma cell lines including SMMC-7721 and BEL-7402 were detected. After transfection of MEG3-siRNA or AP1G1 overexpression plasmid, the proliferative and invasive abilities of hepatoma cells were detected through cell counting kit-8 (CCK-8) and cell invasion assay. The effects of MEG3 and AP1G1 on the cell cycle of hepatoma cell lines were examined using flow cytometry. Western blot was conducted to estimate the changes in the protein levels of AP1G1, p-PI3K, p-AKT and VEGF before and after transfection.
The level of MEG3 in hepatoma cancer tissues and cell lines was significantly reduced, especially in patients with advanced liver cancer. Knockdown of MEG3 significantly promoted proliferation and invasion of hepatoma cells, but accelerated cell cycle. Western blot analysis revealed that knockdown of MEG3 reduced the level of AP1G1 and activated the PI3K/AKT pathway. In addition, rescue experiments demonstrated that overexpression of AP1G1 partially reversed the promotive effect of lowly-expressed MEG3 on cell proliferation and invasion, suggesting that low expression of MEG3 may activate PI3K/AKT pathway by inhibiting AP1G1 expression.
Low expression of MEG3 could promote the proliferative and invasive abilities of hepatoma cells and accelerate cell cycle. The mechanism may be related to the inhibition of AP1G1 expression and activation of PI3K/AKT pathway.
本研究旨在探讨母系表达基因 3（MEG3）在肝癌中的生物学功能，以及磷脂酰肌醇 3-激酶/蛋白激酶 B（PI3K/AKT）通路在调节肝癌细胞增殖和侵袭中的潜在机制。
采用定量实时聚合酶链反应（qRT-PCR）检测 72 对肝癌组织及其相应癌旁组织中 MEG3 的水平。检测包括 SMMC-7721 和 BEL-7402 在内的肝癌细胞系中 MEG3 和 AP1G1 的表达水平。转染 MEG3-siRNA 或 AP1G1 过表达质粒后，通过细胞计数试剂盒-8（CCK-8）和细胞侵袭实验检测肝癌细胞的增殖和侵袭能力。通过流式细胞术检测 MEG3 和 AP1G1 对肝癌细胞系细胞周期的影响。Western blot 检测转染前后 AP1G1、p-PI3K、p-AKT 和 VEGF 蛋白水平的变化。
MEG3 在肝癌组织和细胞系中的水平明显降低，尤其是在晚期肝癌患者中。敲低 MEG3 显著促进肝癌细胞的增殖和侵袭，但加速了细胞周期。Western blot 分析显示，敲低 MEG3 降低了 AP1G1 的水平并激活了 PI3K/AKT 通路。此外，挽救实验表明，AP1G1 的过表达部分逆转了低表达 MEG3 对细胞增殖和侵袭的促进作用，提示 MEG3 低表达可能通过抑制 AP1G1 表达来激活 PI3K/AKT 通路。
MEG3 低表达可促进肝癌细胞的增殖和侵袭能力，并加速细胞周期。其机制可能与抑制 AP1G1 表达和激活 PI3K/AKT 通路有关。
