M2 macrophage-derived exosomes and miR-132-3p promote gastric cancer cell aggressiveness and attenuate ferroptosis-related changes.

Purpose: This study aimed to explore the correlation between the ability of M2-type tumor-correlated macrophage-derived exosomes (EXOs) to trigger the aggressiveness of gastric cancer (GC) cells and the miR-132-3p expression. Methods: EXOs were isolated from the conditioned media of M0 and M2 macrophages and characterized by transmission electron microscopy and Western blotting. miR-132-3p expression was determined by qRT-PCR. HGC-27 cells were divided into the control, miR-132-3p mimic, miR-132-3p inhibitor, M0-EXO, and M2-EXO groups. Cell viability, proliferation, migration, and invasion were assessed using CCK-8, EdU, and Transwell assays. Intracellular GSH, SOD, MDA, and iron levels were measured using colorimetric assays. FTH1, LIFR, and GPX4 expressions were detected by Western blotting. RNA sequencing and bioinformatics analyses were performed to investigate miR-132-3p-mediated transcriptional changes and ferroptosis-related pathways in HGC-27 cells. Results: miR-132-3p was significantly enriched in M2 macrophage-derived exosomes and was highly expressed in GC, with its expression associated with tumor stage, grade, and other clinicopathological features. M2-Exo treatment significantly increased miR-132-3p levels in HGC-27 cells. Both miR-132-3p overexpression and M2-Exo treatment enhanced the proliferation, migration, and invasion of HGC-27 cells, and were accompanied by reduced intracellular iron and MDA levels, increased GSH content and SOD activity, upregulated FTH1 and GPX4 expression, and decreased LIFR expression. In contrast, miR-132-3p inhibition produced largely opposite effects. RNA-seq identified 275 differentially expressed genes following miR-132-3p overexpression, including 216 upregulated and 59 downregulated genes. GO and KEGG analyses revealed significant alterations in biological processes and pathways related to oxygen transport, ATP synthesis, oxidative phosphorylation, thermogenesis, spliceosome function, and endoplasmic reticulum protein processing. Integration of the RNA-seq-derived DEGs with FerrDb identified 12 ferroptosis-related DEGs, including 11 upregulated genes and 1 downregulated gene. qRT-PCR validation showed expression patterns broadly consistent with the RNA-seq results. Conclusion: miR-132-3p expression in the EXOs of M2-type macrophages was significantly elevated, and the EXOs of M2-type macrophages significantly triggered the aggressiveness of GC cells and inhibited ferroptosis in GC cells, which may be resulting from the prevention of ferroptosis through the transport of miR-132-3p; nevertheless, the specific mechanism of action needs to be further elucidated.