Chemoresistance remains the major barrier to cancer treatment. Metabolic and epigenetic reprogramming are involved in this process; however, the precise roles and mechanisms are largely unknown. Here, we report that lactate-induced lactylation promotes chemoresistance to anthracyclines by regulating homologous recombination (HR) repair. Using the global lactylome, we revealed the landscape of differentially lactylated sites and proteins in cancer cells isolated from resistant and nonresistant tumors. Specifically, BLM, a crucial helicase in the HR repair process, is highly lactylated at Lys24 by AARS1 in response to chemotherapy. Mechanistically, hyperlactylation of BLM improves its stability by inhibiting MIB1-mediated ubiquitination and increasing its interaction with DNA repair factors, promoting DNA end resection and HR repair. Delactylation of BLM via the Lys24 mutation impairs HR repair and increases anthracycline chemosensitivity. Irinotecan shows synergistic effects and safety for alleviating anthracycline resistance by targeting BLM lactylation and suppressing HR repair in pancancer PDX models. A single-arm, phase I study (identifier NCT06766266) initiated by us suggested that the combination of irinotecan liposomes plus EPI is a feasible and safe treatment strategy for patients with anthracycline-resistant bladder cancer who experience recurrence. These findings exemplify how glycolytic reprogramming regulates HR repair through promoting protein lactylation and highlight the promising therapeutic potential of irinotecan for reversing anthracycline chemoresistance by suppressing BLM lactylation.

A malformed tumour vascular network provokes the nutrient‐deprived tumour microenvironment (TME), which conversely activates endothelial cell (EC) functions and stimulates neovascularization. Emerging evidence suggests that the flexible metabolic adaptability of tumour cells helps to establish a metabolic symbiosis among various cell subpopulations in the fluctuating TME. In this study, the authors propose a novel metabolic link between bladder cancer (BCa) cells and ECs in the nutrient‐scarce TME, in which BCa‐secreted glutamine‐fructose‐6‐phosphate aminotransferase 1 (GFAT1) via small extracellular vesicles (sEVs) reprograms glucose metabolism by increasing hexosamine biosynthesis pathway flux in ECs and thus enhances O‐GlcNAcylation. Moreover, seryl‐tRNA synthetase (SerRS) O‐GlcNAcylation at serine 101 in ECs promotes its degradation by ubiquitination and impeded importin α5‐mediated nuclear translocation. Intranuclear SerRS attenuates vascular endothelial growth factor transcription by competitively binding to the GC‐rich region of the proximal promotor. Additionally, GFAT1 knockout in tumour cells blocks SerRS O‐GlcNAcylation in ECs and attenuates angiogenesis both in vitro and in vivo. However, administration of GFAT1‐overexpressing BCa cells‐derived sEVs increase the angiogenetic activity in the ECs of GFAT1‐knockout mice. In summary, this study suggests that inhibiting sEV‐mediated GFAT1 secretion from BCa cells and targeting SerRS O‐GlcNAcylation in ECs may serve as novel strategies for BCa antiangiogenetic therapy.

Dysregulation of ferroptosis is linked to chemoresistance, and reprogramming of glucose metabolism is involved in this progress. However, the underlying mechanisms remain obscure. Herein, using metabolic profiling, we find that hexosamine biosynthetic pathway (HBP) metabolism and the byproduct, UDP-GlcNAc, are substantially up-regulated in chemoresistant tumor tissues and cells. UDP-GlcNAc-derived O-GlcNAcylation levels increase with the decreased ferroptosis and chemosensitivity in cancer cells. Knockout of the rate-limiting enzyme GFPT1 in HBP metabolism inhibits O-GlcNAcylation, induces ferroptosis, and mitigates chemoresistance of orthotopic bladder cancer in Gfpt1^−/− mice. The global O-GlcNAcylation omics mapped the O-GlcNAcylated sites and proteins in resistant and nonresistant tumor cells, showing that NR3C1 is highly O-GlcNAcylated at Thr²⁹⁹ in response to chemotherapy. The chromatin immunoprecipitation sequencing delineates that NR3C1 O-GlcNAcylation at Thr²⁹⁹ prominently enhances transcriptional activity of GPX4 by facilitating the binding of NR3C1 on GPX4 promoter, inhibiting ferroptosis. Higher O-GlcNAcylation of NR3C1 improves protein stability and reduces proteasome-dependent degradation by suppressing ubiquitination. Inhibition of NR3C1 O-GlcNAcylation via Thr²⁹⁹ mutant or knockout of NR3C1 facilitates ferroptosis and improves chemosensitivity of resistant cancer cells in vitro and in vivo. In addition, we propose a novel predicting model for chemoresistance based on the GFPT1 and NR3C1 levels in pre-chemotherapy biopsy tissues through a training set and a validation set. These findings exemplify how metabolic and epigenetic reprogramming regulates ferroptosis via the GFPT1/NR3C1/GPX4 axis, and implicate NR3C1 O-GlcNAcylation as a potential target for reversing chemoresistance.

Renal ischemia-reperfusion (I/R) injury is a leading cause of acute kidney injury (AKI), with high mortality. Recent studies have reported that human umbilical cord mesenchymal stem cells (HucMSCs) play an important role in repairing organ and tissue injuries because of their unique characteristics. However, the potential of HucMSC extracellular vesicles (HucMSC-EVs) to promote the repair of renal tubular cells remains to be explored. This study found that HucMSC-EVs derived from HucMSCs played a protective role and were associated with kidney I/R injury. We found that miR-148b-3p in HucMSC-EVs had a protective effect against kidney I/R injury. HK-2 cells overexpressing miR-148b-3p were protected against I/R injury by inhibiting apoptosis. Next, the target mRNA of miR-148b-3p was predicted online, and the target mRNA, pyruvate dehydrogenase kinase 4 (PDK4), was identified and verified using dual luciferase. We discovered that I/R injury significantly increased endoplasmic reticulum (ER) stress, whereas siR-PDK4 inhibited these effects and protected against I/R injury. Interestingly, after administrating HucMSC-EVs to HK-2 cells, PDK4 expression and ER stress induced by I/R injury were significantly inhibited. HK-2 ingested miR-148b-3p from HucMSC-EVs, and its ER induced by I/R injury was significantly deregulated. This study suggests that HucMSC-EVs protect kidneys from I/R injury during the early I/R stage. These results suggest a new mechanism for HucMSC-EVs in treating AKI and provide a new treatment strategy for I/R injury.

Ferroptotic waves aggravate kidney ischemia-reperfusion injury and drive delayed graft function (DGF). We demonstrate that elevated glycolysis and lactate production in graft kidney correlate with ferroptosis and functional impairment. A signaling axis composed of the long non-coding RNA IGIP-5, microRNA 670-3p, and lactate dehydrogenase A promotes lactate secretion from injured tubular cells, inducing lactylation and ferroptosis in neighboring cells and triggering ferroptotic waves. Lactylome profiling identifies that nucleophosmin 1 (NPM1), an epigenetic regulator, is lactylated at lysine 257 by the lactyltransferase AARS1. Suppressing NPM1 lactylation—via K257 mutation, AARS1 knockout, or taurochenodeoxycholic acid—upregulates SLC7A11 and inhibits ferroptosis. Mechanistically, lactylation stabilizes NPM1 by reducing MDM2-mediated ubiquitination and strengthens SLC7A11 repression, disrupting cystine metabolism. In mouse allografts, blocking lactate shuttle-mediated NPM1 lactylation prevents ferroptotic propagation and ameliorates graft function. Additionally, we develop an early prediction model for DGF using postoperative urinary lactate concentrations. These findings reveal a metabolic-epigenetic axis driving ferroptotic propagation and propose NPM1 lactylation as a therapeutic target for DGF.