An integrative ex vivo platform for mapping therapy-induced cellular adaptations in urothelial carcinoma: GLUT1 as an example of chemotherapy-induced metabolic resistance

In muscle-invasive bladder cancer (MIBC), the variability in response to systemic treatments and the lack of clinically useful predictive biomarkers highlight the need for approaches that reflect tumor adaptation to therapy, to guide the rational intensification or reduction of treatment in the era of combination therapy. We integrated ex vivo tumor tissue slice cultures with 10x Genomics Visium spatial transcriptomics to map treatment-induced adaptations in a physiologically relevant context. Findings were validated in two retrospective cohorts: Cohort 1 (n=54 MIBC patients treated with NAC and cystectomy) and Cohort 2 (n=38 patients with upper-tract or bladder urothelial carcinoma, including metachronous recurrences). Spatial profiling revealed that cisplatin–gemcitabine rapidly induced a localized hypoxic–glycolytic program dominated by GLUT1 (SLC2A1). In Cohort 1, high baseline GLUT1 independently predicted incomplete pathological response and lymph-node involvement (multivariable AUC 0.71, 95% CI 0.59–0.83). Increased GLUT1 expression from TURBT to cystectomy was associated with worse disease-specific survival and recurrence (HR 4.23, 95% CI 1.40–13.68; HR 5.04, 95% CI 1.73–15.40). In Cohort 2, elevated GLUT1 was observed in upper-tract tumors that relapsed in the bladder. This regimen-agnostic platform identifies therapy-induced resistance programs in native tissue. GLUT1 emerges as a candidate marker of chemotherapy-induced metabolic reprogramming, warranting prospective validation and applicability to modern combination regimens.