Department of Hepatobiliary Surgery, Shenzhen University General Hospital, Shenzhen, China.
Department of Hepatobiliary Surgery, Southwest Hospital, Chongqing, China.
Ann Hepatol. 2019 Nov-Dec;18(6):869-878. doi: 10.1016/j.aohep.2019.07.005. Epub 2019 Aug 24.
MiR-122 has been regarded as a tumor suppressor. Toll-like receptor 4 (TLR4) has been found to be closely related to metastasis and immune escape of hepatocellular carcinoma (HCC). In the study, we sought to investigate the effect of miR-122 on HCC and the expression of TLR4.
Real-time PCR and Western blot were performed to detect the expressions of target factors. CCK-8 and flow cytometry analysis were employed to evaluate cell viability and apoptosis, respectively. Luciferase reporter assay was used to determine whether miR-122 could directly regulate the expression of TLR4. Enzyme-linked Immuno Sorbent Assay was adopted to detect the secretion of inflammatory cytokines.
Both down-regulation of miR-122 and up-regulation of TLR4 were found to be correlated with low overall survival rate of HCC patients. TLR4 may be a direct target gene of miR-122. Over-expression of miR-122 induced apoptosis and inhibited cell viability of HCC by down-regulating TLR4, enhanced the expression of pro-apoptotic genes and suppressed the expression of anti-apoptotic genes. MiR-122 inhibited expressions and activities of inflammatory cytokines, including vascular endothelial growth factor (VEGF), interleukin 6 (IL-6), cyclooxygenase-2 (Cox-2) and prostaglandin E2 (PGE2) and also reduced the expression of matrix metallopeptidase 9 (MMP-9). Furthermore, activities of phosphatidylinositide 3-kinases (PI3K), Akt and nuclear factor-kappa B (NF-κB) were suppressed by miR-122.
Down-regulation of miR-122 facilitated the immune escape of HCC by targeting TLR4, which was related to PI3K/Akt/NF-κB signaling pathways. Our study may provide a possible strategy for the treatment of HCC.
miR-122 被认为是一种肿瘤抑制因子。Toll 样受体 4（TLR4）已被发现与肝细胞癌（HCC）的转移和免疫逃逸密切相关。在这项研究中，我们试图研究 miR-122 对 HCC 及 TLR4 表达的影响。
实时 PCR 和 Western blot 用于检测靶因子的表达。CCK-8 和流式细胞术分析分别用于评估细胞活力和细胞凋亡。荧光素酶报告基因实验用于确定 miR-122 是否可以直接调节 TLR4 的表达。酶联免疫吸附试验用于检测炎症细胞因子的分泌。
miR-122 下调和 TLR4 上调均与 HCC 患者总体生存率降低相关。TLR4 可能是 miR-122 的直接靶基因。通过下调 TLR4，过表达 miR-122 诱导 HCC 细胞凋亡并抑制细胞活力，增强促凋亡基因的表达，抑制抗凋亡基因的表达。miR-122 抑制血管内皮生长因子（VEGF）、白细胞介素 6（IL-6）、环氧化酶-2（Cox-2）和前列腺素 E2（PGE2）等炎症细胞因子的表达和活性，并降低基质金属蛋白酶 9（MMP-9）的表达。此外，miR-122 抑制了磷脂酰肌醇 3-激酶（PI3K）、Akt 和核因子-κB（NF-κB）的活性。
miR-122 通过靶向 TLR4 促进 HCC 的免疫逃逸，这与 PI3K/Akt/NF-κB 信号通路有关。我们的研究可能为 HCC 的治疗提供了一种可能的策略。
