O-GlcNAcylation regulation of RIPK1-dependent apoptosis dictates sensitivity to sunitinib in renal cell carcinoma

Receptor interacting protein kinase 1 (RIPK1) has emerged as a key regulatory molecule that influences the balance between cell death and cell survival. Under external stress, RIPK1 determines whether a cell undergoes RIPK-dependent apoptosis (RDA) or survives by activating NF-κB signaling. However, the role and mechanisms of RIPK1 on sunitinib sensitivity in renal cell carcinoma (RCC) remain elusive. In this study, we demonstrated that the O-linked β-N-acetylglucosamine modification (O-GlcNAcylation) of RIPK1 induces sunitinib resistance in RCC by inhibiting RDA. O-GlcNAc transferase (OGT) specifically interacts with RIPK1 through its tetratricopeptide repeats (TPR) domain and facilitates RIPK1 O-GlcNAcylation. The O-GlcNAcylation of RIPK1 at Ser331, Ser440 and Ser669 regulates RIPK1 ubiquitination and the formation of the RIPK1/FADD/Caspase-8 complex, thereby inhibiting sunitinib-induced RDA in RCC. Site-specific depletion of O-GlcNAcylation on RIPK1 affects the formation of the RIPK1/FADD/Caspase 8 complex, leading to increased sunitinib sensitivity in RCC. Our data highlight the significance of aberrant RIPK1 O-GlcNAcylation in the development of sunitinib resistance and indicate that targeting RIPK1 O-GlcNAcylation could be a promising therapeutic strategy for RCC.