目的：检测circSMRCA5在非小细胞肺癌（NSCLC）组织和细胞中的表达，以及其在NSCLC发生发展中的潜在功能和机制。方法：用qPCR 法检测circSMARCA5在NSCLC 组织中的表达。使用慢病毒转染法将circSMARCA5过表达质粒和对照质粒pLC5分别转染人肺癌A549 和H1975 细胞。采用qPCR法检测稳定转染细胞中circSMARCA5的表达水平。通过CCK-8、克隆形成、细胞周期和异种移植瘤实验检测circSMARCA5 过表达对A549 和H1975 细胞生物学行为的影响。通过转录组测序、KEGG和GO富集分析，确定circSMARCA5可能的靶基因。分别构建circSMARCA5过表达A549、Lewis 细胞BABL/c 裸鼠和免疫正常的C57 小鼠皮下移植瘤模型，观察circSMARCA5对裸鼠皮下移植瘤生长的影响，流式细胞术检测对Lewis 细胞移植瘤组织中Treg 细胞水平的影响。结果：circSMARCA5在NSCLC 组织中呈高表达（P<0.01）。过表达circSMARCA5可以在体外促进NSCLC 细胞的增殖（P<0.05，P<0.01）。体内实验中，circSMARCA5 可以促进裸鼠皮下移植瘤的生长（P<0.01）。机制上，经KEGG 和GO 富集分析，确定C-C 趋化因子配体5（CCL5）为circSMARCA5 的下游靶基因。过表达circSMARCA5 组A549 和H1975 细胞中CCL5 的表达量增加（均P<0.05）。circSMARCA5 介导的CCL5 上调促进了免疫正常的C57 小鼠皮下移植瘤的生长。C57 小鼠皮下移植瘤制备成的单细胞悬液行流式细胞术检测显示，circSMARCA5过表达组的Treg 细胞比例高于对照组[（3.1±0.5）% vs （1.0±0.1）%，P<0.05]。结论：circSMARCA5在NSCLC组织中呈高表达，其可能通过CCL5将Treg 细胞招募到肿瘤中，导致肿瘤的免疫逃逸，促进NSCLC的进展。

Objective: To investigate the expression of circSMRCA5 in non-small cell lung cancer (NSCLC) tissues and cells and its potential function and mechanism in the occurrence and development of NSCLC. Methods: The expression of circSMARCA5 in NSCLC tissues was detected by qPCR. The circSMARCA5 over-expression plasmid and the control plasmid pLC5 were transfected into human lung cancer A549 and H1975 cells using the lentiviral transfection method, and the expression levels of circSMARCA5 in the stably transfected cell lines were detected by qPCR. The effects of circSMARCA5 over-expression on the biological behaviors of A549 and H1975 cells were examined by CCK-8, clone formation, cell cycle, and tumor xenografts. Mechanistically, transcriptome sequencing, KEGG and GO enrichment analysis were conducted to identify possible target genes of circSMARCA5. Subcutaneous xenograft models were constructed in BABL/c nude mice and immunocompetent C57 mice by using circSMARCA5-over-expressed NSCLC cells or Lewis cells. The effect of circSMARCA5 on the growth of subcutaneously transplanted tumors in nude mice was observed, and its effect on the contents of Treg cells in Lewis cells transplanted tumor tissues was detected by flow cytometry. Results: circSMARCA5 was highly expressed in NSCLC tissues (P<0.01). Over-expression of circSMARCA5 could promote the proliferation of NSCLC cells in vitro (P<0.05, P<0.01). In in vivo experiments,circSMARCA5 could promote the growth of the transplanted tumors in nude mice (P<0.01). Mechanistically, C-C chemokine ligand 5 (CCL5) was identified as a downstream target gene of circSMARCA5 by KEGG and GO enrichment analysis. The expression of CCL5 was increased in A549 and H1975 cells of circSMARCA5 over-expression group (P<0.05). circSMARCA5-mediated upregulation of CCL5 promoted the growth of subcutaneous tumors in immunocompetent C57 mice. Flow cytometry of single-cell suspensions prepared from subcutaneous tumors of C57 mice showed that the proportion of Treg cells in the circSMARCA5 over-expression group was higher than that in the control group ([3.1±0.5]% vs [1.0±0.1]%, P<0.05). Conclusion: circSMARCA5 is highly expressed in NSCLC tissues. circSMARCA5 may recruit Treg cells via CCL5, leading to the immune escape of tumors and promoting the progression of NSCLC.

国家自然科学基金（No.81803942）；南京中医药大学自然科学基金（No.XZR2020001）