Department of Oncology Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China.
Int J Oncol. 2018 Dec;53(6):2566-2578. doi: 10.3892/ijo.2018.4595. Epub 2018 Oct 12.
Gastric cancer (GC) is one of the leading causes of cancer-associated mortality worldwide. The aim of the present study was to investigate the mechanism of microRNA-4295 (miR-4295), which regulates cisplatin (DDP)-induced apoptosis in GC cells through the leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1)-mediated epidermal growth factor receptor (EGFR)/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway. Two cell lines were selected, one with the highest expression of miR-4295 and one with the lowest expression of LRIG1, for the experiments. The half maximal inhibitory concentration of DDP in the human GC MKN-28 and MKN-45 cell lines was calculated, and mitochondrial membrane potentials of the GC cells were detected by tetramethylrhodamine, ethyl ester, perchlorate staining. The proliferation and apoptosis of GC cells with or without DDP treatment were assessed by MTT assay and plate colony formation, as well as flow cytometry and TUNEL staining. Western blot analysis and reverse transcription-quantitative polymerase chain reaction were employed to determine the expression of EGFR/PI3K/Akt signaling pathway-related genes and apoptosis-related genes. LRIG1 was identified as a target gene of miR-4295. The expression of miR-4295 was upregulated, and the expression of LRIG1 was downregulated in GC cells. Furthermore, DDP enhanced the decrease in miR-4295 expression and the increase in LRIG1 expression in GC cells. miR-4295 promoted the proliferation and inhibited the DDP-induced apoptosis of GC cells without DDP treatment. In addition, miR-4295 increased the expression levels of EGFR, PI3K, Akt, p-PI3K and p-Akt, suggesting that miR-4295 promotes the activation of the EGFR/PI3K/Akt signaling pathway by targeting LRIG1. miR-4295 targeted and negatively regulated LRIG1 expression to activate the EGFR/PI3K/Akt signaling pathway, thereby promoting the proliferation of the GC cells and inhibiting the apoptosis of the GC cells induced by DDP. Therefore, miR-4295 may be a novel therapeutic target in patients with GC.
胃癌（GC）是全球癌症相关死亡的主要原因之一。本研究旨在探讨 microRNA-4295（miR-4295）的机制，该机制通过富含亮氨酸重复和免疫球蛋白样结构域 1（LRIG1）调节顺铂（DDP）诱导的 GC 细胞凋亡，通过表皮生长因子受体（EGFR）/磷酸肌醇 3-激酶（PI3K）/蛋白激酶 B（Akt）信号通路。选择了两种细胞系进行实验，一种是 miR-4295 表达最高的细胞系，另一种是 LRIG1 表达最低的细胞系。计算人胃癌 MKN-28 和 MKN-45 细胞系中 DDP 的半最大抑制浓度，并通过四甲基罗丹明乙酯过氯酸染色检测 GC 细胞的线粒体膜电位。通过 MTT 测定和平板集落形成以及流式细胞术和 TUNEL 染色评估有或没有 DDP 处理的 GC 细胞的增殖和凋亡。采用 Western blot 分析和逆转录定量聚合酶链反应检测 EGFR/PI3K/Akt 信号通路相关基因和凋亡相关基因的表达。LRIG1 被鉴定为 miR-4295 的靶基因。miR-4295 的表达上调，GC 细胞中 LRIG1 的表达下调。此外，DDP 增强了 GC 细胞中 miR-4295 表达的降低和 LRIG1 表达的增加。miR-4295 促进 GC 细胞的增殖并抑制无 DDP 处理时 GC 细胞的 DDP 诱导凋亡。此外，miR-4295 增加了 EGFR、PI3K、Akt、p-PI3K 和 p-Akt 的表达水平，表明 miR-4295 通过靶向 LRIG1 促进 EGFR/PI3K/Akt 信号通路的激活。miR-4295 靶向并负调控 LRIG1 表达，激活 EGFR/PI3K/Akt 信号通路，从而促进 GC 细胞的增殖并抑制 DDP 诱导的 GC 细胞凋亡。因此，miR-4295 可能是 GC 患者的一种新的治疗靶点。
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