Gastric Cancer Department, Liaoning Cancer Hospital & Institute (Cancer Hospital of China Medical University), No. 44 Xiaoheyan Road, Dadong District, Shenyang City, Liaoning Province 110042, China.
Medical Oncology Department of Gastrointestinal Cancer, Liaoning Cancer Hospital & Institute (Cancer Hospital of China Medical University), No. 44 Xiaoheyan Road, Dadong District, Shenyang City, Liaoning Province 110042, China.
Exp Mol Pathol. 2020 Oct;116:104487. doi: 10.1016/j.yexmp.2020.104487. Epub 2020 Jul 1.
Aberrantly expressed long non-coding RNAs (lncRNAs) are critical instigators of gastric cancer (GC) progression and metastasis. The ceRNA (competing endogenous RNAs) network is well-known in modulating tumor pathological and physiological processes. This research aims to determine the more effective molecular mechanisms of lncRNA PCGEM1 (prostate cancer gene expression marker 1).
Bioinformatics database and Ago2-RIP were performed to predict and verify the potential targets of lncRNA PCGEM1. Both gain- and loss-of-function experiments were carried out to dissect the biological functions of RNAs. Fluorescence in situ hybridization, dual-luciferase reporter assays, western blot, and real-time PCR (RT-PCR) experiments were utilized to determine the pathophysiological pathways of competitive endogenous RNAs (ceRNAs).
GC cells expressed high levels of cytoplasmic PCGEM1. Loss-of-function experiments displayed that the silencing of PCGEM1 suppressed metastatic and invasive cell qualities. PCGEM1 was also found to have associations with miR-129-5p. Subsequently, luciferase reporter and RIP experiments, together with RT-PCR, verified that PCGEM1 functioned as a ceRNA of P4HA2 (Prolyl 4-Hydroxylase Subunit Alpha 2) via sponging miR-129-5p to up-regulate P4HA2 expression. Finally, the rescue assays determined that P4HA2 overexpression rescued the inhibited cell invasion and metastasis caused by PCGEM1 down-regulation.
These findings found that an over-expression of PCGEM1 in GC acts as a miR-129-5p sponge, leading to higher levels of P4HA2. The PCGEM1/miR-129-5p/P4HA2 axis was confirmed to possess a crucial role in GC metastasis and invasion, suggesting its utility as a potential diagnostic and therapeutic biomarker.
异常表达的长链非编码 RNA（lncRNA）是胃癌（GC）进展和转移的关键启动子。竞争性内源 RNA（ceRNA）网络在调节肿瘤病理生理过程中是众所周知的。本研究旨在确定 lncRNA PCGEM1（前列腺癌基因表达标志物 1）更有效的分子机制。
生物信息学数据库和 Ago2-RIP 用于预测和验证 lncRNA PCGEM1 的潜在靶标。进行增益和失活功能实验以剖析 RNA 的生物学功能。荧光原位杂交、双荧光素酶报告基因测定、western blot 和实时 PCR（RT-PCR）实验用于确定竞争性内源 RNA（ceRNA）的病理生理途径。
GC 细胞表达高水平的细胞质 PCGEM1。失活实验显示，PCGEM1 的沉默抑制了转移性和侵袭性细胞特性。还发现 PCGEM1 与 miR-129-5p 有关。随后，荧光素酶报告和 RIP 实验以及 RT-PCR 验证了 PCGEM1 通过海绵 miR-129-5p 作为 P4HA2（脯氨酰 4-羟化酶亚单位 α 2）的 ceRNA 发挥作用，从而上调 P4HA2 表达。最后，挽救实验确定 P4HA2 过表达挽救了 PCGEM1 下调引起的抑制细胞侵袭和转移。
这些发现发现 GC 中 PCGEM1 的过度表达充当 miR-129-5p 的海绵，导致 P4HA2 水平升高。PCGEM1/miR-129-5p/P4HA2 轴被证实在 GC 转移和侵袭中具有重要作用，表明其作为潜在的诊断和治疗生物标志物的用途。
