DHODH Drives Sunitinib Resistance Via a Non‐Enzymatic Mechanism by Inhibiting TRIM28 Ubiquitination and Consequent VEGFA Activation in RCC

Sunitinib, a tyrosine kinase inhibitor, exerts its crucial therapeutic effect in renal cell carcinoma (RCC) primarily by inhibiting tumor angiogenesis and cellular proliferation. However, despite its initial efficacy, therapeutic resistance invariably develops in many RCC patients, underscoring the urgent need for novel strategies to overcome this limitation. We constructed patient-derived xenograft (PDX) models using surgically resected RCC tissues and subsequently established stable sunitinib-resistant and sunitinib-sensitive PDX models. Proteomic profiling was performed to identify key regulators involved in sunitinib resistance. Mechanistic studies were conducted to investigate the molecular interactions among DHODH, TRIM28, and VEGFA. The therapeutic potential of lisaftoclax was evaluated in combination with sunitinib. Proteomic profiling identified DHODH as a key regulator in the development of sunitinib resistance in RCC. Mechanistically, DHODH competes with the E3 ligase TRIM37 for binding to TRIM28, thereby stabilizing TRIM28 by inhibiting its ubiquitination. TRIM28 subsequently activates VEGFA transcription, which promotes sunitinib resistance in RCC. Lisaftoclax, a small-molecule inhibitor that disrupts the DHODH-TRIM28 interaction, potentiates sunitinib efficacy and exerts a synergistic therapeutic effect. Collectively, our findings identify DHODH as a critical therapeutic target for overcoming sunitinib resistance in RCC and provide a novel strategy for the treatment of RCC.