ALYREF-mediated m5C modification of CCNA1 drives escape from cell-cycle arrest and contributes to pazopanib resistance in Renal Cell Carcinoma.

Pazopanib, a first-line tyrosine kinase inhibitor for advanced renal cell carcinoma (RCC), faces significant clinical limitations due to acquired resistance. In this study, we reveal a novel mechanism underlying pazopanib resistance in RCC, driven by a senescence-like phenotype without cell-cycle arrest. Transcriptomic profiling identified ALYREF as a key upregulated m5C reader in pazopanib resistant cells. Mechanistically, ALYREF stabilizes CCNA1 mRNA via m5C modification, promoting Cyclin A1 expression. The Cyclin A1-CDK2 complex phosphorylates p21 at Thr-57, inducing its cytoplasmic translocation and abrogating its inhibitory effect on cell cycle progression, thereby facilitating G1-S transition. Our findings uncover a critical ALYREF-Cyclin A1-p21 axis in RCC and suggest that targeting this pathway may provide novel therapeutic strategies to overcome pazopanib resistance.