Endoplasmic Reticulum Stress Causes Liver Cancer Cells to Release Exosomal miR-23a-3p and Up-regulate Programmed Death Ligand 1 Expression in Macrophages
Endoplasmic Reticulum Stress Causes Liver Cancer Cells to Release Exosomal miR-23a-3p and Up-regulate Programmed Death Ligand 1 Expression in Macrophages
复制标题
内质网应激导致肝癌细胞释放外泌体 miR-23a-3p 并上调巨噬细胞中程序性死亡配体 1 的表达
DOI：
10.1002/hep.30607
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发表时间：
2019-07-01
期刊：
影响因子：
13.5
通讯作者：
Sun, Guoping
中科院分区：
文献类型：
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作者：
Liu, Jiatao;Fan, Lulu;Sun, Guoping
内质网（ER）应激促进肿瘤细胞逃避免疫监视。然而，其潜在机制仍不清楚。我们假设ER应激诱导肝细胞癌（HCC）细胞释放外泌体，其通过调节巨噬细胞中程序性死亡配体1（PD-L1）的表达来减弱抗肿瘤免疫。在这项研究中，我们证明了几种ER应激标志物（葡萄糖调节蛋白78，转录激活因子6，蛋白激酶R样ER激酶和肌醇需要酶1 α）的表达在HCC组织中上调，并与HCC患者的总生存率和临床病理评分呈负相关。ER应激相关蛋白的表达与HCC组织中CD 68（+）巨噬细胞募集和PD-L1表达呈正相关。高通量测序分析将miR-23 a-3 p鉴定为来源于衣霉素（TM）处理的HCC细胞（Exo-TM）的外来体中最丰富的微小RNA之一。HCC组织中的miR-23 a-3 p水平与总生存率呈负相关。用Exo-TM处理在体外和体内上调巨噬细胞中PD-L1的表达。生物信息学分析表明，miR-23 a-3 p通过磷酸酶和张力蛋白同源物（PTEN）-磷脂酰肌醇3-激酶-蛋白激酶B（AKT）途径调节PD-L1表达。体外转染和共培养实验证实了这一观点，这些实验表明miR-23 a-3 p抑制了巨噬细胞中的PTEN表达，随后升高了磷酸化AKT和PD-L1的表达。最后，T细胞与Exo-TM刺激的巨噬细胞共培养降低了CD 8（+）T细胞比例和白细胞介素-2的产生，但增加了体外T细胞凋亡。结论：ER应激的HCC细胞释放外泌体以上调巨噬细胞中的PD-L1表达，其随后通过外泌体miR-23 a-PTEN-AKT途径抑制T细胞功能。我们的研究结果提供了深入了解肿瘤细胞如何逃避抗肿瘤免疫的机制。
Endoplasmic reticulum (ER) stress promotes tumor cell escape from immunosurveillance. However, the underlying mechanisms remain unknown. We hypothesized that ER stress induces hepatocellular carcinoma (HCC) cells to release exosomes, which attenuate antitumor immunity by modulating the expression of programmed death ligand 1 (PD-L1) in macrophages. In this study, we demonstrated that expression of several ER stress markers (glucose-regulated protein 78, activating transcription factor 6, protein kinase R-like ER kinase, and inositol-requiring enzyme 1 alpha) was up-regulated in HCC tissues and negatively correlated with the overall survival and clinicopathological scores in patients with HCC. Expression of ER stress-related proteins positively correlated with CD68(+) macrophage recruitment and PD-L1 expression in HCC tissues. High-throughput sequencing analysis identified miR-23a-3p as one of the most abundant microRNAs in exosomes derived from tunicamycin (TM)-treated HCC cells (Exo-TMs). miR-23a-3p levels in HCC tissues negatively correlated with overall survival. Treatment with Exo-TMs up-regulated the expression of PD-L1 in macrophages in vitro and in vivo. Bioinformatics analysis suggests that miR-23a-3p regulates PD-L1 expression through the phosphatase and tensin homolog (PTEN)-phosphatidylinositol 3-kinase-protein kinase B (AKT) pathway. This notion was confirmed by in vitro transfection and coculture experiments, which revealed that miR-23a-3p inhibited PTEN expression and subsequently elevated phosphorylated AKT and PD-L1 expression in macrophages. Finally, coculture of T cells with Exo-TM-stimulated macrophages decreased CD8(+) T-cell ratio and interleukin-2 production but increased T-cell apoptosis in vitro. Conclusion: ER-stressed HCC cells release exosomes to up-regulate PD-L1 expression in macrophages, which subsequently inhibits T-cell function through an exosome miR-23a-PTEN-AKT pathway. Our findings provide insight into the mechanism how tumor cells escape from antitumor immunity.