Cancer-associated fibroblast exosomal miR-214-3p regulated by hnRNPA2B1 promotes cisplatin resistance by inhibiting ferroptosis

BACKGROUND: Cisplatin resistance continues to represent a significant clinical challenge in the treatment of osteosarcoma. Accumulating evidence suggests that cancer-associated fibroblast (CAF) play a pivotal role in shaping a chemotherapy-resistant tumor microenvironment through exosome-mediated intercellular communication. In this study, we identified hnRNPA2B1 as a critical RNA-binding protein involved in the regulation of exosomal miRNA sorting within CAF, thereby contributing to the development of cisplatin resistance in osteosarcoma. MATERIALS AND METHODS: Single-cell RNA sequencing was performed on cisplatin-sensitive samples and cisplatin-resistant samples. Expression levels of hnRNPA2B1 in CAF subsets were analyzed. Exosome secretion from CAF was quantified. RNA immunoprecipitation assays were used to assess hnRNPA2B1 binding to miR-214-3p. Functional assays were conducted by transferring CAF-derived exosomes to osteosarcoma cells, followed by evaluation of GPX4 expression, ferroptosis, and cisplatin sensitivity. GPX4 overexpression experiments were performed both in vitro and in vivo to assess its ability to reverse the effects of exosomal miR-214-3p. RESULTS: Single-cell RNA sequencing analysis demonstrated that CAF subpopulations exhibiting high expression levels of hnRNPA2B1 were predominantly present in cisplatin-resistant tumors. We further found that hnRNPA2B1 enhanced exosome secretion and facilitated the selective incorporation of miR-214-3p into exosomes by recognizing a conserved GGAG motif. The exosomal transfer of miR-214-3p to osteosarcoma cells resulted in the downregulation of GPX4 expression, leading to reduced ferroptosis and increased chemoresistance. Notably, GPX4 overexpression effectively counteracted the antiferroptotic and pro-survival effects of CAF-derived exosomal miR-214-3p both in vitro and in vivo . CONCLUSIONS: Collectively, our findings elucidated a novel mechanism by which hnRNPA2B1 governed exosomal miRNA sorting in CAF and highlight the CAF exosomal miR-214-3p/GPX4 axis as a key mediator of ferroptosis evasion and cisplatin resistance in osteosarcoma. Targeting exosome-mediated communication within the tumor microenvironment may offer promising therapeutic approaches for overcoming chemotherapy resistance.