Exosomes Derived from Non-small Cell Lung Cancer Cells Transfer LINC00467 to Induce the Proliferation of Cancer-associated Fibroblasts.

Cancer-associated fibroblasts (CAFs) significantly contribute to non-small cell lung cancer (NSCLC) progression by remodeling the extracellular matrix and mediating paracrine signaling. Although exosomal lncRNAs are key regulators of tumor-stroma interactions, the specific functions of individual lncRNAs remain poorly understood. LINC00467 and miR-133b were selected for further investigation in this study based on previous reports, prior evidence of lncRNA-miRNA interaction, and preliminary experimental observations in NSCLC-derived exosomes and fibroblast activation models. Exosomes from A549 and primary NSCLC cells were isolated using a polymer-based precipitation method and validated by Western blotting. LINC00467 was silenced via siRNA, and isolated exosomes were co-cultured with MRC5 fibroblasts and CAFs. Fibroblast activation and proliferation markers were assessed by Western blotting and cell counting kit assays. miR-133b involvement was examined using quantitative real-time PCR and inhibitor-based rescue experiments. Exosome-pretreated MRC5 fibroblasts were also co-cultured with A549 cells. Exosomal LINC00467 was enriched in NSCLC-derived exosomes. Knockdown of LINC00467 in NSCLC cells reduced its exosomal levels, leading to decreased expression of activation markers (α-SMA, COL-I, COL-III) and cell cycle regulators (Cyclin B1, Cyclin D1) in recipient fibroblasts. In addition, exosomes with LINC00467 knockdown inhibited the cell proliferation of fibroblasts. It was also revealed that LINC00467-deficient exosomes upregulated miR-133b expression. Importantly, inhibition of miR-133b reversed the suppressive effects of LINC00467 knockdown. Exosome-pretreated fibroblasts enhanced A549 cell proliferation, colony formation, and migration in vitro. This study identifies a novel exosomal LINC00467/miR-133b axis that promotes fibroblast activation and proliferation in NSCLC.