Lactate Dehydrogenase LDHA in Neutrophil-Derived Exosomes Mediates Histone Lactylation to Regulate Ferroptosis in Breast Cancer

Background: Neutrophils are the most abundant white blood cells in circulation and play a critical role in the inflammatory response. Histone modifications, especially the lysine acetylation, have drawn increasing attention in cancer research area. The aim of this research is to explore the molecular mechanisms underlying the regulation of neutrophil-derived exosomes on breast cancer.MethodsNeutrophils were isolated from peripheral blood and identified by flow cytometry. Exosomes were extracted from cell culture medium and assessed by expression of TSG101 and CD81 by western blot assay, transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). Exosomes were labeled with PKH26 for cancer cell uptake experiment. Cell growth was measured by CCK-8 and EdU assay. Ferroptosis was assessed by levels of lipid peroxidation and ferrous iron. Interaction between LDHA with glutathione peroxidase 4 (GPX4) gene was measured by chromatin immunoprecipitation (ChIP).ResultsDepletion of lysine acetyltransferase 2A (LDHA) in neutrophils led to reduced LDHA and H3K18la enrichment in breast cancer cells. Neutrophils-derived exosomal LDHA regulated the in vitro growth of breast cancer cells. Knockdown of LDHA in neutrophil-derived exosomes induced ferroptosis, as manifested by elevated lipid ROS and ferrous iron. Knockdown of LDHA reduced the enrichment of H3K18la on GPX4 gene. Knockdown of LDHA significantly suppressed the proliferation and induced ferroptosis in breast cancer cells, whereas treatment with ferroptosis inhibitor and lactate provider abolished these effects.ConclusionsOur findings demonstrated that neutrophils-derived exosomes deliver LDHA to modulate the histone acetylation of GPX4, regulating the proliferation and ferroptosis of breast cancer cells.