TRIM26 as a dual regulator of ferroptosis and chemoresistance in gastric cancer through HSF1 ubiquitination and exosomal miR-24-3p signaling.

Gastric cancer (GC) remains a major global health concern due to its frequent late-stage diagnosis, persistent chemoresistance, and high metastatic potential, all of which contribute to poor clinical outcomes. TRIM26, an E3 ubiquitin ligase with emerging tumor-suppressive functions, has been implicated in various malignancies; however, its precise role in GC has not been fully elucidated. This study elucidates in ferroptosis and chemoresistance while uncovering stromal-tumor crosstalk mechanisms underlying its suppression. Using public databases and clinical GC specimens and established cell lines (MGC-803, HGC27, MKN45), we observed significant downregulation of TRIM26 expression in tumor tissues compared to adjacent normal counterparts (p < 0.001), which correlated with advanced clinical stage and unfavorable prognosis. Functional assays including CCK-8, wound healing, colony formation, and Transwell migration, demonstrated that TRIM26 knockdown significantly enhanced GC cell proliferation, migration, and invasion, whereas TRIM26 overexpression reversed these malignant phenotypes. Mechanistically, TRIM26 induced ferroptosis via HSF1 ubiquitination and degradation, leading to reduced glutathione (GSH) levels and elevated levels of reactive oxygen species (ROS) and malondialdehyde (MDA). Additionally, we identified cancer-associated fibroblast (CAF)-derived exosomal miR-24-3p as a key upstream regulator that directly targets the 3' untranslated region (3' UTR) of TRIM26, thereby suppressing its expression, as confirmed by luciferase reporter assays. In cisplatin-resistant GC models (MGC803/DDP and AGS/DDP), prolonged cisplatin exposure resulted in a pronounced reduction in TRIM26 expression, corresponding with a 5.6-fold increase in IC(50) and a heightened metastatic profile. TRIM26 silencing further potentiated chemoresistance and invasive behavior, which coincided with epithelial-mesenchymal transition (EMT), as evidenced by decreased E-cadherin and increased N-cadherin and Vimentin expression. In contrast, TRIM26 restoration re-sensitized resistant GC cells to cisplatin and mitigated their metastatic capacity. Collectively, these findings reveal TRIM26 as a pivotal suppressor of GC progression, acting through the regulation of ferroptosis and EMT while being modulated by stromal exosomal miR-24-3p Therapeutic strategies aimed at restoring TRIM26 expression or disrupting the miR-24-3p/TRIM26/HSF1 axis may offer promising avenues for overcoming chemoresistance and limiting metastasis in GC.