Neutrophil-derived exosomes inhibit gastric cancer progression via miR-101-3p-mediated suppression of MCL1

BACKGROUND: Neutrophils, serving as crucial innate immune cells, exert anti-tumor effects through cytotoxic mediators, antibody-dependent responses, and coordination of immune networks. They also release exosomes that carry bioactive molecules such as microRNAs (miRNAs). Our previous work identified neutrophil-derived exosomes (N-Exo) as contributors to their anti-tumor activity, but the underlying mechanisms remain unclear. METHODS: Functional experiments integrating high-throughput sequencing and validation assays were performed to screen and identify key anti-tumor miRNAs in N-Exo. An in vivo subcutaneous xenograft mouse tumor model assessed the therapeutic effects of N-Exo-delivered miR-101-3p on tumor growth. Bioinformatics analysis combined with experimental validation, including dual-luciferase reporter assays, co-immunoprecipitation (Co-IP), and chromatin immunoprecipitation (ChIP), elucidated the mechanism by which the key miRNA suppresses tumorigenesis through targeting specific genes and signaling pathways. Recombinant interleukin-36 gamma (rmIL-36γ) was used to stimulate neutrophils, and functional assays were performed to evaluate its effect. RESULTS: Hsa-miR-101-3p was enriched in N-Exo. N-Exo-delivered miR-101-3p directly targets MCL1 to suppress its expression and indirectly inhibits MCL1 transcription via regulation of the EZH2/c-Myc axis, collectively promoting apoptosis in gastric cancer (GC) cells. Furthermore, rmIL-36γ priming upregulated miR-101-3p expression in neutrophils and enhanced their anti-tumor effects. CONCLUSION: We demonstrate that N-Exo exerts tumor-suppressive effects by delivering miR-101-3p, which dually targets and suppresses MCL1 expression. Moreover, rmIL-36γ treatment enhances both miR-101-3p abundance and anti-tumor efficacy in neutrophils. These findings highlight the N-Exo/miR-101-3p/MCL1 axis as a therapeutic target and support cytokine priming as a strategy to enhance neutrophil-based cancer therapy.