GFPT2 drives sunitinib resistance of renal cell carcinoma via enzyme-dependent and -independent manners

Intrinsic resistance to sunitinib in advanced renal cell carcinoma (RCC) remains a major barrier to improving patient survival outcomes. However, the molecular mechanisms driving this resistance remain incompletely elucidated. In this study, we first observed elevated glutamine levels in sunitinib-resistant RCC models; notably, glutamine deprivation substantially impaired the growth and proliferation of RCC cells. We further demonstrated that abnormal upregulation of GFPT2-a key enzyme in glutamine metabolism-was associated with reduced sunitinib sensitivity and enhanced drug resistance in RCC. Mechanistically, we uncovered that GFPT2 modulates cellular O-GlcNAcylation levels, which in turn enhances the stability and nuclear translocation of YAP1-ultimately contributing to reduced sunitinib sensitivity. In addition, we also identified an additional non-metabolic role of GFPT2: it directly interacts with the Kelch domain of KEAP1, thereby reducing NRF2 binding to this domain and suppressing NRF2 ubiquitination-dependent degradation. Consequently, this regulatory cascade dysregulates the transcription of downstream antioxidant genes (e.g., HMOX1 and NQO1), ultimately driving NRF2-dependent sunitinib resistance in RCC. Critically, this KEAP1-NRF2 axis-mediated mechanism operates independently of GFPT2's metabolic role in regulating O-GlcNAcylation. Collectively, our findings demonstrate that GFPT2 modulates sunitinib sensitivity and drives drug resistance in RCC via dual mechanisms: a metabolic pathway (O-GlcNAcylation-YAP1) and a non-metabolic pathway (KEAP1-NRF2). Targeting the non-metabolic functions of GFPT2 thus holds promise for enhancing sunitinib sensitivity in RCC while potentially mitigating treatment-related side effects.