Circ_0092012 knockdown restrains non-small cell lung cancer progression by inhibiting cell malignant phenotype and immune escape through microRNA-635/programmed death ligand 1 axis

Circular RNAs have been reported to play roles in non-small cell lung cancer (NSCLC) progression. Herein, this work aimed to investigate the potential value of circ_0092012 in NSCLC progression. Levels of genes and proteins were detected using quantitative reverse transcription-polymerase chain reaction and Western blot, respectively. The growth, malignant phenotypes and immune escape in NSCLC were investigated. The binding between microRNA (miR)-635 and circ_0092012 or programmed death ligand 1 (PDL1) was verified. Circ_0092012 was highly expressed in NSCLC. Circ_0092012 deficiency suppressed NSCLC cell proliferation, invasion and migration, moreover, as well as was able to inhibit the apoptosis of CD8 + T cells and induce higher interferon-γ and tumor necrosis factor-α levels when co-cultured with peripheral blood mononuclear cells. Mechanistically, circ_0092012 sponged miR-635, which targeted PDL1. Further rescue experiments suggested that the anticancer effects of circ_0092012 knockdown were reversed by miR-635 inhibition. Additionally, miR-635 re-expression suppressed NSCLC cell malignant phenotypes mentioned above and immune escape, which were attenuated by PDL1 overexpression. Moreover, circ_0092012 deletion retarded NSCLC growth <i>in vivo</i>. In all, circ_0092012 knockdown suppressed NSCLC cell oncogenic phenotypes and immune escape by miR-635/PDL1 axis.

已有研究表明，环状RNA（circular RNAs）参与非小细胞肺癌（non-small cell lung cancer, NSCLC）的发生发展。本研究旨在探讨circ_0092012在非小细胞肺癌进展中的潜在价值。分别采用定量反转录聚合酶链反应和蛋白质印迹法（Western blot）检测相关基因与蛋白的表达水平。研究了非小细胞肺癌细胞的增殖、恶性表型及免疫逃逸情况。验证了微小RNA（microRNA, miR）-635与circ_0092012或程序性死亡配体1（programmed death ligand 1, PDL1）之间的靶向结合关系。实验结果显示，circ_0092012在非小细胞肺癌中呈高表达。敲低circ_0092012可抑制非小细胞肺癌细胞的增殖、侵袭与迁移；此外，在与外周血单个核细胞（peripheral blood mononuclear cells）共培养时，其还可抑制CD8+ T细胞凋亡，并提升干扰素-γ（interferon-γ）与肿瘤坏死因子-α（tumor necrosis factor-α）的分泌水平。机制研究显示，circ_0092012可作为分子海绵吸附miR-635，而miR-635可靶向调控PDL1的表达。进一步的拯救实验（rescue experiments）结果表明，抑制miR-635可逆转敲低circ_0092012所产生的抗肿瘤效应。此外，恢复miR-635的表达可抑制前述非小细胞肺癌细胞的恶性表型与免疫逃逸，而这一效应可被PDL1过表达所削弱。敲低circ_0092012还可在体内抑制非小细胞肺癌的生长。综上，敲低circ_0092012可通过调控miR-635/PDL1轴，抑制非小细胞肺癌细胞的致瘤表型与免疫逃逸。