Department of Pathology, The First Affiliated Hospital of General Hospital of People's Liberation Army, Beijing 100048, P.R. China.
Mol Med Rep. 2019 Sep;20(3):2484-2492. doi: 10.3892/mmr.2019.10475. Epub 2019 Jul 8.
Immune checkpoint blockade is a promising therapeutic strategy against various human malignancies. MicroRNAs (miRNAs/miRs) regulate gene expression, by repressing mRNA translation or promoting its degradation. The aim of the current study was to investigate the role and molecular mechanisms of miR‑140 in Helicobacter pylori (Hp)‑associated gastric cancer, and to examine its relationship with immune function in gastric cancer. Gastritis tissue samples from gastritis patients, and gastric cancer tissue samples from gastric cancer patients were collected for miR‑140 expression detection. miR‑140 expression was detected using reverse transcription‑quantitative polymerase chain reaction, and protein expression was measured by western blotting. TargetScan and dual luciferase reporter assays were used to reveal the association between miR‑140 and programmed cell death‑ligand 1 (PD‑L1). BGC823 cell proliferation was detected by MTT assays. Ex vivo immune analysis by flow cytometry and ELISA were used to analyze immune function. It was demonstrated that miR‑140 expression was significantly reduced in Hp‑positive gastric cancer. PD‑L1 was confirmed as a direct target of miR‑140 in gastric cancer cells. In addition, PD‑L1 expression was significantly increased in Hp‑positive gastric cancer. Overexpression of miR‑140 significantly suppressed gastric cancer cell proliferation through regulating PD‑L1 expression. In vivo experiments also revealed that miR‑140 markedly repressed tumor growth in the C57BL/6 mice. Furthermore, it was determined that the tumor‑suppressive role of miR‑140 in gastric cancer was associated with increased cytotoxic CD8+ T cell and reduced myeloid‑derived suppressive and regulatory T cell infiltration. miR‑140 significantly prevented mammalian target of rapamycin signaling in gastric cancer cells. Notably, these miR‑140 overexpression‑induced alterations were inhibited by PD‑L1 plasmid. These findings indicated that miR‑140 exerted an anti‑gastric cancer effect by targeting immune checkpoint molecule PD‑L1. Thus, miR‑140 may be a promising and novel immunotherapeutic target for gastric cancer treatment.
免疫检查点阻断是一种针对各种人类恶性肿瘤的有前途的治疗策略。microRNAs（miRNAs/miRs）通过抑制 mRNA 翻译或促进其降解来调节基因表达。本研究旨在探讨 miR-140 在幽门螺杆菌（Hp）相关胃癌中的作用和分子机制，并研究其与胃癌免疫功能的关系。收集胃炎患者的胃炎组织样本和胃癌患者的胃癌组织样本，用于检测 miR-140 的表达。采用逆转录-定量聚合酶链反应检测 miR-140 的表达，采用 Western blot 法检测蛋白表达。采用靶标扫描和双荧光素酶报告基因检测试剂盒揭示 miR-140 与程序性死亡配体 1（PD-L1）之间的关联。采用 MTT 法检测 BGC823 细胞增殖。采用流式细胞术和 ELISA 进行体外免疫分析，分析免疫功能。结果表明，Hp 阳性胃癌中 miR-140 的表达明显降低。PD-L1 被证实为胃癌细胞中 miR-140 的直接靶标。此外，Hp 阳性胃癌中 PD-L1 的表达明显增加。过表达 miR-140 通过调节 PD-L1 表达，显著抑制胃癌细胞增殖。体内实验还表明，miR-140 可显著抑制 C57BL/6 小鼠肿瘤生长。此外，确定 miR-140 在胃癌中的肿瘤抑制作用与增加的细胞毒性 CD8+T 细胞和减少的髓源性抑制性和调节性 T 细胞浸润有关。miR-140 显著抑制胃癌细胞中的哺乳动物雷帕霉素靶蛋白信号通路。值得注意的是，这些 miR-140 过表达诱导的改变被 PD-L1 质粒抑制。这些结果表明，miR-140 通过靶向免疫检查点分子 PD-L1 发挥抗胃癌作用。因此，miR-140 可能是治疗胃癌的一种有前途的新型免疫治疗靶标。
