The clinical implications of fibroblast activation protein (FAP)-positive CAFs (FAP+CAFs) were evaluated based on tumor specimens from NSCLC patients and bioinformatic analysis of online databases. CAF-specific circular RNAs (circRNAs) were screened by circRNA microarrays of primary human CAFs and matched normal fibroblasts (NFs). Survival analyses were performed to assess the prognostic value of circNOX4 in NSCLC clinical samples. The biological effects of circNOX4 were investigated by gain- and loss-of-function experiments in vitro and in vivo. Fluorescence in situ hybridization, luciferase reporter assays, RNA immunoprecipitation, and miRNA rescue experiments were conducted to elucidate the underlying mechanisms of fibroblast activation. Cytokine antibody array, transwell coculture system, and enzyme-linked immunosorbent assay (ELISA) were performed to investigate the downstream effectors that promote cancer metastasis.
FAP+CAFs were significantly enriched in metastatic cancer samples, and their higher abundance was correlated with the worse overall survival in NSCLC patients. A novel CAF-specific circRNA, circNOX4 (hsa_circ_0023988), evoked the phenotypic transition from NFs into CAFs and promoted the migration and invasion of NSCLC in vitro and in vivo. Clinically, circNOX4 correlated with the poor prognosis of advanced NSCLC patients. Mechanistically, circNOX4 upregulated FAP by sponging miR-329-5p, which led to fibroblast activation. Furthermore, the circNOX4/miR-329-5p/FAP axis activated an inflammatory fibroblast niche by preferentially inducing interleukin-6 (IL-6) and eventually promoting NSCLC progression. Disruption of the intercellular circNOX4/IL-6 axis significantly suppressed tumor growth and metastatic colonization in vivo.
Our study reveals a role of the circRNA-induced fibroblast niche in tumor metastasis and highlights that targeting the circNOX4/FAP/IL-6 axis is a promising strategy for the intervention of NSCLC metastasis.
方法:基于NSCLC患者的肿瘤标本和在线数据库的生物信息学分析,评估成纤维细胞活化蛋白(FAP)阳性CAFs(FAP+CAFs)的临床意义。通过原代人CAF和匹配的正常成纤维细胞(NFs)的circRNA微阵列筛选CAF特异性环状RNA(circRNAs)。进行生存分析以评估circNOX4在NSCLC临床样本中的预后价值。通过体外和体内的功能增益和功能丧失实验研究了circNOX4的生物学作用。荧光原位杂交,荧光素酶报告基因测定,RNA免疫沉淀,和miRNA拯救实验进行,以阐明成纤维细胞活化的潜在机制。细胞因子抗体阵列,Transwell共培养系统,和酶联免疫吸附试验(ELISA)来研究促进癌症转移的下游效应物。
结果:FAP+CAFs在转移癌样本中显著富集,在非小细胞肺癌患者中,它们的丰度较高与总生存期较差相关。一种新的CAF特异性circRNA,circNOX4(hsa_circ_0023988),诱导了NFs向CAFs的表型转变,促进了NSCLC的体内外迁移和侵袭。临床上,circNOX4与晚期NSCLC患者的不良预后相关。机械上,circNOX4通过海绵作用miR-329-5p上调FAP,导致成纤维细胞活化。此外,circNOX4/miR-329-5p/FAP轴通过优先诱导白细胞介素-6(IL-6)并最终促进NSCLC进展激活炎性成纤维细胞生态位.细胞间circNOX4/IL-6轴的破坏可显着抑制体内肿瘤的生长和转移性定植。
结论:我们的研究揭示了circRNA诱导的成纤维细胞小生境在肿瘤转移中的作用,并强调靶向circNOX4/FAP/IL-6轴是干预NSCLC转移的有希望的策略。