Ginkgolide A Suppresses Osteosarcoma Proliferation and Activates the Apoptotic Pathway by Targeting the KAT2A-H3K18la...

Osteosarcoma (OS) is a highly aggressive primary bone malignancy characterized by profound metabolic reprogramming and limited therapeutic options. Although histone lactylation has recently emerged as a metabolic-epigenetic mechanism linking glycolysis to gene regulation, its functional relevance and therapeutic tractability in OS remain largely unexplored. Here, we identify the natural diterpene lactone Ginkgolide A (GA) as a potent suppressor of OS progression through targeted disruption of lactate-driven histone lactylation.

Human Osteosarcoma (OS) MG63 and U2OS cell lines were given GA to find cell viability loss, migration, and apoptosis, which were examined using CCK-8 assay, wound-healing assay, Annexin V/PI flow cytometry, TUNEL staining, qRT-PCR, and immunoblotting. Gas Chromatography Mass Spectrometry (GC-MS) metabolomics was employed to profile the metabolic changes induced by GA, with a focus on the glycolytic pathway. In-depth ligation patterns and regulatory mechanisms of histone were studied herein through sitespecific immunoblotting, Chromatin Immunoprecipitation (ChIP)-qPCR, immunofluorescence, and Molecular Docking (MD) tools. Later on, the antitumor potential of GA was further examined using a nude mouse xenograft model.

GA significantly checked OS cell proliferation and migration by modulating apoptosis, with halfmaximal inhibitory concentrations of 10.83 μM (MG63 cells) and 12.88 μM (U2OS cells). GA boosts mitochondrial apoptosis, indicated by enhanced BAX and caspase-3/-9 levels while repressing the expression level of BCL-2. Integrated metabolomic profiling indicated a marked decline of intracellular lactate and acetate levels, which establishes a metabolic basis for downstream epigenetic remodeling by GA. GA showed a site-specific epigenetic regulation by targeted suppression of histone H3 lysine-18 lactylation (H3K18la) with no effect on non-target lactylation sites. GA may downregulate expression of lactyltransferase KAT2A, alter H3K18laassociated promoter occupancy of apoptosis-linked genes, and induce pro-apoptotic transcriptional activity. In the xenograft in vivo model, GA modulated apoptosis to significantly inhibit tumor growth and expression of Ki67.

Findings reported in the present study confirmed that GA directly interacts with KAT2A, inhibits lactylation by disrupting the binding of KAT2A with H3K18, thereby regulating OS cell proliferation.

GA markedly inhibits proliferation, migration, and induces apoptosis in OS cells primarily by regulating the glycolytic pathway, i.e., reduction in lactate levels, subsequent targeting of KAT2A, downregulation of H3K18 lactylation, and ultimate transcriptional regulation of apoptosis. It is hereby recognized that GA mediates metabolic inhibition by selective epigenetic reprogramming of the KAT2A-H3K18 lactylation axis. The current findings establish histone lactylation as a key mechanism in OS inhibition and highlight metabolicepigenetic cross-talk as a promising therapeutic regimen for aggressive bone malignancies.