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Cancer-derived exosomal miR-138-5p modulates polarization of tumor-associated macrophages through inhibition of KDM6B.

ABSTRACT: Rationale: Differential activation of macrophages correlates closely with tumor progression, and the epigenetic factor lysine demethylase 6B (KDM6B, previously named JMJD3) mediates the regulation of macrophage polarization through an unknown mechanism. Methods: We developed a suspension coculture system comprising breast cancer cells and macrophages and used RT-qPCR and western blotting to measure KDM6B expression. Bioinformatics and luciferase reporter assays were used to identify candidate microRNAs of cancer cells responsible for the downregulation of KDM6B. To determine if exosomes mediated the transfer of miR-138-5p between cancer cells to macrophages, we treated macrophages with exosomes collected from the conditioned medium of cancer cells. The effects of exosomal miR-138-5p on macrophage polarization were measured using RT-qPCR, flow cytometry, and chromatin immunoprecipitation assays. We employed a mouse model of breast cancer, metastatic to the lung, to evaluate the effects on tumor metastasis of macrophages treated with miR-138-5p-enriched exosomes. To develop a diagnostic evaluation index, the levels of exosomal miR-138-5p in samples from patients with breast cancer were compared to those of controls. Results: Coculture of breast cancer cells led to downregulation of KDM6B expression in macrophages. Cancer cell-derived exosomal miR-138-5p inhibited M1 polarization and promoted M2 polarization through inhibition of KDM6B expression in macrophages. Macrophages treated with exosomal miR-138-5p promoted lung metastasis, and the level of circulating exosomal miR-138-5p positively correlated with the progression of breast cancer. Conclusion: Our data suggest that miR-138-5p was delivered from breast cancer cells to tumor-associated macrophages via exosomes to downregulate KDM6B expression, inhibit M1 polarization, and stimulate M2 polarization. Therefore, exosomal miR-138-5p represents a promising prognostic marker and target for the treatment of breast cancer.

SUBMITTER: Xun J

PROVIDER: S-EPMC8171095 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Myocardial infarction arises from an excessive or prolonged inflammatory response, leading to ventricular remodeling or impaired cardiac function. Macrophages exhibit different polarization types associated with inflammation both at steady state and after myocardial infarction. Exosomal miR-146a-5p has been identified as an important molecule in the cardiovascular field in recent years. However, the effect of cardiomyocyte-derived exosomal miR-146a-5p on macrophages has not yet been elucidated. Initially, we found that exosomes with low expression of miR-146a-5p derived from myocardial infarction tissues modulated macrophage polarization. To determine whether cardiomyocyte-derived exosomal miR-146a-5p mediated macrophage polarization, we treated macrophages with exosomes rich in miR-146a-5p collected from neonatal mouse cardiomyocytes. The effects of exosomal miR-146a-5p on macrophage polarization were measured using RT-qPCR, transwell assays, and western blotting. The results showed that the increased expression of miR-146a-5p promoted M1 macrophage polarization, inhibited M2 macrophage polarization, and increased the expression of VEGFA. However, the decreased expression of exosomalmiR-146a-5p showed the opposite trends. Interestingly, in contrast to treatment with the solitary miR-146a-5p mimic, exosomal miR-146a-5p derived from neonatal mouse cardiomyocytes reduced TNFα and iNOS expression. In addition, when macrophages were activated by the miR-146a-5p mimic or exosomal miR-146a-5p, the expression of TNF receptor-associated factor 6 (TRAF6), a target gene of miR-146a-5p, was reduced significantly. Taken together, these findings indicate that exosomal miR-146a-5p derived from cardiomyocytes could stimulate M1 macrophage polarization to induce an inflammatory reaction, while targeting TRAF6, exerting an anti-inflammatory effect. Exosomal miR-146a-5p plays important roles in macrophages, illuminating a novel potential therapeutic target in myocardial infarction.

Project description:Stroma-infiltrating immune cells, such as tumor-associated macrophages (TAM), play an important role in regulating tumor progression and chemoresistance. These effects are mostly conveyed by secreted mediators, among them several cathepsin proteases. In addition, increasing evidence suggests that stroma-infiltrating immune cells are able to induce profound metabolic changes within the tumor microenvironment. In this study, we aimed to characterize the impact of cathepsins in maintaining the TAM phenotype in more detail. For this purpose, we investigated the molecular effects of pharmacological cathepsin inhibition on the viability and polarization of human primary macrophages as well as its metabolic consequences. Pharmacological inhibition of cathepsins B, L, and S using a novel inhibitor, GB111-NH2, led to changes in cellular recycling processes characterized by an increased expression of autophagy- and lysosome-associated marker genes and reduced adenosine triphosphate (ATP) content. Decreased cathepsin activity in primary macrophages further led to distinct changes in fatty acid metabolites associated with increased expression of key modulators of fatty acid metabolism, such as fatty acid synthase (FASN) and acid ceramidase (ASAH1). The altered fatty acid profile was associated with an increased synthesis of the pro-inflammatory prostaglandin PGE2, which correlated with the upregulation of numerous NFkB-dependent pro-inflammatory mediators, including interleukin-1 (IL-1), interleukin-6 (IL-6), C-C motif chemokine ligand 2 (CCL2), and tumor necrosis factor-alpha (TNFα). Our data indicate a novel link between cathepsin activity and metabolic reprogramming in macrophages, demonstrated by a profound impact on autophagy and fatty acid metabolism, which facilitates a pro-inflammatory micromilieu generally associated with enhanced tumor elimination. These results provide a strong rationale for therapeutic cathepsin inhibition to overcome the tumor-promoting effects of the immune-evasive tumor micromilieu.

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Cancer-derived exosomal miR-138-5p modulates polarization of tumor-associated macrophages through inhibition of KDM6B.

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