Exosomal microRNA-588 from M2 polarized macrophages contributes to cisplatin resistance of gastric cancer cells.

Background: Gastric cancer is a prevalent malignant cancer with a high incidence and significantly affects the health of modern people globally. Cisplatin (DDP) is one of the most common and effective chemotherapies for patients with gastric cancer, but DDP resistance remains a severe clinical challenge.

Aim: To explore the function of M2 polarized macrophages-derived exosomal microRNA (miR)-588 in the modulation of DDP resistance of gastric cancer cells.

Methods: M2 polarized macrophages were isolated and identified by specific markers using flow cytometry analysis. The exosomes from M2 macrophages were identified by transmission electron microscopy and related markers. The uptake of the PKH67-labelled M2 macrophages-derived exosomes was detected in SGC7901 cells. The function and mechanism of exosomal miR-588 from M2 macrophages in the modulation of DDP resistance of gastric cancer cells was analyzed by CCK-8 assay, apoptosis analysis, colony formation assay, Western blot analysis, qPCR analysis, and luciferase reporter assay in SGC7901 and SGC7901/DDP cells, and by tumorigenicity analysis in nude mice.

Results: M2 polarized macrophages were isolated from mouse bone marrow stimulated with interleukin (IL)-13 and IL-4. Co-cultivation of gastric cancer cells with M2 polarized macrophages promoted DDP resistance. M2 polarized macrophages-derived exosomes could transfer in gastric cancer cells to enhance DDP resistance. Exosomal miR-588 from M2 macrophages contributed to DDP resistance of gastric cancer cells. miR-588 promoted DDP-resistant gastric cancer cell growth . miR-588 was able to target cylindromatosis (CYLD) in gastric cancer cells. The depletion of CYLD reversed miR-588 inhibition-regulated cell proliferation and apoptosis of gastric cancer cells exposed to DDP.

Conclusion: In conclusion, we uncovered that exosomal miR-588 from M2 macrophages contributes to DDP resistance of gastric cancer cells by partly targeting CYLD. miR-588 may be applied as a potential therapeutic target for the treatment of gastric cancer.