Abstract 7328: EPR imaging of oxygen consumption driven by NQO1-activated compounds in FH-deficient renal tumors

Abstract Patients with hereditary leiomyomatosis and renal cell carcinoma (HLRCC), characterized by mutations in the fumarate hydratase (FH) gene, are at risk for development of aggressive FH-deficient RCCs. FH-deficient tumor cells undergo a pronounced and irreversible metabolic shift to lactate fermentation due in part to loss and mutation of mitochondrial DNA. Fumarate accumulation in FH-deficient tumor cells leads to increased expression of NAD(P)H-quinone oxidoreductase 1 (NQO1) through activation of the NRF2 transcription factor. Although several therapeutic agents have shown promise in the treatment of FH-deficient RCC, clinical outcomes in patients remain unsatisfactory. In this study, we examined the mechanism and therapeutic efficacy of isobutyl-deoxynyboquinone (IB-DNQ), which undergoes futile redox cycling in the presence of NQO1 and oxygen, leading to sustained generation of the highly reactive and toxic superoxide anion. First, we found that patient-derived FH-deficient tumor cells exhibit minimal oxygen consumption in vitro, and EPR oxygen mapping of FH-deficient tumor xenografts in vivo revealed that tumor oxygen levels were elevated relative to other genetically defined in vivo models of RCC. Infusion of IB-DNQ in tumor-bearing animals resulted in rapid and robust non-mitochondrial oxygen consumption in FH-deficient tumor xenografts as measured by both EPR oxygen imaging and photoacoustic mapping of tumor hemoglobin saturation. Repeated doses of IB-DNQ resulted in reduced tumor growth rates. Metabolomic analyses revealed that IB-DNQ treatment strongly suppressed glycolysis and reduced cellular ATP levels by rapidly depleting NADH and NADPH in FH-deficient tumor cells. Finally, [1-13C]pyruvate hyperpolarized MR spectroscopy revealed decreased conversion of pyruvate to lactate in FH-deficient tumor xenografts following IB-DNQ treatment, providing a direct measurement of the impact of IB-DNQ on lactate fermentation in vivo. The combination of these in vivo imaging techniques and metabolite measurements demonstrate that NQO1-activated quinones can effectively target aerobic glycolysis in FH-deficient tumors which rely heavily on lactate fermentation for growth. Citation Format: Yuki Shibata, Shun Kishimoto, Ye Yang, Ming-Hui Wei, Julia Medina-Velazquez, Burchelle Blackman, Jeeva Munasinghe, Viraj Chegu, Vaishnavi S. Srirama, Tyler A. On, Nallathamby Devasahayam, Chandramouli V. Gadisetti, Jeffrey R. Brender, Murali C. Krishna, Daniel R. Crooks, William Marston Linehan. EPR imaging of oxygen consumption driven by NQO1-activated compounds in FH-deficient renal tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 7328.