Reprogramming Transcriptional Networks via CREB1 Lactylation at K122 Activates HMGB1-Mediated NETosis and Chemoresistance.

Cisplatin resistance remains a major obstacle in ovarian cancer treatment. While lactate-rich tumor microenvironments promote chemoresistance, the role of lysine lactylation (Kla) in this process remains poorly understood. Here, we identify CREB1 lactylation at K122 as a pivotal epigenetic driver of cisplatin resistance. Through quantitative lactyl-proteomics, we found CREB1 K122 as a hyperlactylated site specifically enriched in cisplatin-resistant ovarian cancer cells and patient tissues. This modification is dynamically regulated by the opposing activities of p300 (writer) and SIRT1 (eraser). Functionally, a lactylation-mimetic CREB1 mutant (K122Q) conferred robust resistance, enhancing cell survival and tumor growth, whereas a lactylation-deficient mutant (K122R) sensitized cells to cisplatin. Mechanistically, CUT&Tag analysis revealed that K122la remodels chromatin architecture, redistributing CREB1 binding from promoters to distal enhancers and substantially expanding its target repertoire. This transcriptional rewiring specifically activated neutrophil extracellular trap (NETosis) programs, with high mobility group box 1 (HMGB1) emerging as a key downstream effector. Lactylated CREB1 promotes HMGB1 transcription and subsequent exosomal secretion into the tumor microenvironment. Secreted HMGB1 then engages Toll-like receptor 4 (TLR4) on neutrophils to trigger NETosis, establishing a chemoprotective niche. Clinically, cisplatin-resistant patients exhibited elevated tumor K122 lactylation and serum exosomal HMGB1 levels. Most importantly, we developed a tumor-targeted lipid nanoparticle (LNP) system delivering a lactylation-deficient CREB1 K122R competitive peptide. This nanotherapeutic approach, particularly when combined with cisplatin, potently suppressed tumor growth in vivo and reduced serum exosomal HMGB1 levels, effectively reversing chemoresistance. Our work unveils the lactate-CREB1 K122la-HMGB1-NETs axis as a metabolic-epigenetic-immune driver of cisplatin resistance and provides a promising nanomedicine strategy for overcoming treatment resistance in ovarian cancer.