Lactate-induced lactylation enhances BMAL1 transcription and nuclear translocation, promoting bevacizumab resistance in glioblastoma through VEGFA

PURPOSE: Resistance to bevacizumab (Bev) remains a major challenge in the management of glioblastoma multiforme (GBM). Our previous work indicated that BMAL1 participates in lactate metabolism in GBM and may be involved in the mechanisms underlying Bev resistance. However, the specific roles of BMAL1 and lactate in this process require further investigation. EXPERIMENTAL DESIGN: This study employed a comprehensive strategy combining in vitro GBM cell line models, patient-derived xenografts (PDX), and in vivo mouse studies. Functional assays (CCK-8, 3D spheroid invasion), molecular techniques (ChIP-qPCR, Co-IP, IP-MS), and biochemical analyses were performed to dissect the mechanism. The clinical relevance of our findings was validated in five independent GBM cohorts and through analysis of human GBM tissues. RESULTS: We identified a previously unrecognized signaling axis in which lactate promotes BMAL1 expression via H3K18la modification at its promoter. In addition, lactate induces BMAL1 protein lactylation at lysine 123, which facilitates its nuclear translocation. IP-MS further showed that lactylated BMAL1 displays a strengthened interaction with TUBA1C, a protein essential for its nuclear import. This lactylation-dependent BMAL1/TUBA1C complex subsequently enhances VEGFA transcription, thereby driving Bev resistance. Importantly, targeting this pathway either by silencing BMAL1, inhibiting lactate transporters, or introducing a lactylation-deficient BMAL1-K123 mutant effectively restored Bev sensitivity in vitro and in vivo. CONCLUSIONS: These findings reveal a novel mechanism through which lactate-mediated lactylation of BMAL1 promotes Bev resistance in GBM, supporting the lactate/BMAL1/TUBA1C/VEGFA axis as a promising therapeutic target for overcoming Bev resistance in GBM patients.