RAD51 succinylation regulates homologous recombination and contributes to the chemosensitivity in cancer.

Genomic instability and metabolic reprogramming are core hallmarks of cancer, yet how they are mechanistically interconnected remains unclear. Here, we demonstrate that succinyl-coenzyme A (CoA), a tricarboxylic acid (TCA) cycle metabolite and protein succinylation donor, modulates homologous recombination (HR) by regulating RAD51 succinylation. OXCT1 succinylates RAD51 at K285, whereas HDAC11 removes this modification. RAD51 succinylation disrupts BRCA2 interaction, impairs RAD51 foci formation, and suppresses HR. Upon DNA damage, ATM-dependent phosphorylation of HDAC11 enhances the interaction with RAD51, promoting RAD51 desuccinylation and inhibiting HR. In breast cancer models, elevated RAD51 succinylation correlates with reduced HR capacity and increased sensitivity to the PARP inhibitor olaparib, whereas diminished succinylation confers resistance. Moreover, a cell-penetrating peptide that disrupts the RAD51-HDAC11 interaction increases RAD51 succinylation and synergizes with chemotherapy. Collectively, our findings uncover a metabolic-epigenetic mechanism linking protein succinylation to HR and genomic stability and identify RAD51 succinylation as a predictive biomarker and therapeutic target in cancer.