Exosomal LINC01614 from Gastric Cancer Cells Drives Treg Differentiation.

This study aimed to investigate the potential mechanism by which LINC01614, a long non-coding RNA (lncRNA), regulates the immune microenvironment of gastric cancer through exosomes. Methodologically, exosomes were isolated by ultracentrifugation (100,000 × g, 70 min) using a transwell co-culture system (human gastric cancer cell lines BGC823 and NCI-N87 were co-cultured with peripheral blood CD4 T cells for 24 h) and identified by transmission electron microscopy (80 kV) and immunoblotting (CD63, CD81, TSG101). Flow cytometry (Foxp3, CD25 antibodies) showed that gastric cancer exosomes induced the differentiation of CD4 T cells into regulatory T cells (Tregs). LINC01614 was identified as a key molecule by integrating GEO (GSE95667), TCGA, and exoRBase2.0 databases (screening criteria: logFC > 1), and its high expression in gastric cancer cells and exosomes was confirmed by qRT-PCR (internal reference GAPDH, 2-ΔΔCq method). Functional experiments were performed using lentivirus-mediated overexpression/silencing of LINC01614 to treat BGC823 cells. ELISA revealed that LINC01614 overexpression of exosomes promoted IL-4 secretion by Tregs (p < 0.05), and drove THP-1-derived macrophages to M2 phenotype polarization and enhanced TGF-β release through the JAK-STAT3 pathway (immunoblotting antibodies p-JAK, p-STAT3). CCK-8 and colony formation assay showed that this process together promoted gastric cancer cell proliferation (p < 0.05). At the mechanistic level, the RIP assay (anti-IL-4 antibody pull-down) suggests that LINC01614 may directly interact with IL-4. In summary, this study preliminarily reveals the mechanism by which LINC01614 promotes Treg differentiation and M2 polarization through the exosome pathway to regulate the immune microenvironment of gastric cancer, providing a theoretical basis for targeting LINC01614 to enhance immunotherapy.