FOXD1 upregulates DARS2-mediated glycolysis to drive cisplatin resistance in bladder cancer

Chemotherapy remains the most effective systemic treatment for bladder cancer (BLCA), with cisplatin as the primary agent. However, the frequent development of cisplatin resistance limits its clinical efficacy. Forkhead box D1 (FOXD1) is implicated in BLCA progression, yet its role in mediating cisplatin resistance remains unexplored.

FOXD1 expression and its correlation with patient prognosis in BLCA were analyzed using the TCGA database. Cisplatin-resistant BLCA cell lines (T24-R and HT-1376-R) were established by treatment with gradient concentrations of cisplatin. qRT-PCR and Western blot were performed to detect the expression levels of FOXD1, β-catenin, and Aspartyl-tRNA Synthetase 2 (DARS2). Cell viability, proliferation, cell cycle, and apoptosis were assessed using CCK-8, colony formation assays, and flow cytometry. Co-IP was performed to examine the interaction between FOXD1 and β-catenin. Glycolysis levels in BLCA cells were determined using specific assay kits.

FOXD1 was highly expressed in BLCA tissues and correlated with poor prognosis. Knockdown of FOXD1 inhibited proliferation and cell cycle progression, promoted apoptosis, and enhanced cisplatin sensitivity in T24-R cells, while reducing β-catenin nuclear translocation and DARS2 expression. Overexpression of FOXD1 exerted the opposite effects on HT-1376-R cells and increased DARS2 expression, which were reversed by β-catenin knockdown. Moreover, knockdown of TCFs/LEF suppressed DARS2 expression. DARS2 was enriched in the glycolysis pathway. Its overexpression promoted glycolysis, proliferation, and cell cycle progression, while inhibiting apoptosis and cisplatin sensitivity in HT-1376-R cells-effects were reversed by 2-DG.

FOXD1 facilitates β-catenin nuclear translocation and upregulates DARS2 to enhance glycolysis, thereby promoting cisplatin resistance in BLCA. These findings identify the FOXD1/β-catenin/DARS2 axis as a potential therapeutic target for overcoming cisplatin resistance in BLCA clinically.