Objective To investigate the effect and underlying mechanism of Prunella vulgaris-derived exosomes loaded with orlistat (PVENs-Orl) on lipid metabolism and malignant biological behaviors of hepatoma cells. Methods PVENs were extracted by ultracentrifugation. After characterization by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA), a PVENs-Orl drug delivery system was constructed. The inhibitory effects of PVENs-Orl on the proliferation, migration and invasion of HepG2 cells were evaluated through CCK-8, cloning, scratch and Transwell assays. The free fatty acids (FFA) uptake, fatty acid synthase (FASN) activity, triglyceride (TG) content, lipid peroxidation indicators and mitochondrial membrane potential and morphology were detected. The expressions of genes related to lipid metabolism and ferroptosis [acyl-CoA synthetase long-chain family member 4 (ACSL4), glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), B-cell lymphoma-2 interacting protein 3 (BNIP3L), lysophosphatidylcholine acyltransferase 3 (LPCAT3), transferrin receptor (TFRC)] was detected by qRT-PCR. Results The PVENs were successfully extracted and characterized, and the constructed PVENs-Orl could be effectively internalized by HepG2 cells. PVENs and PVENs-Orl exhibited dose-dependent inhibition of the proliferation, migration and invasion of HepG2 cells (P < 0.001). In terms of lipid metabolism phenotype, PVENs-Orl could inhibit FASN activity (P < 0.01), and simultaneously cause intracellular accumulation of FFA and TG (P < 0.01). PVENs-Orl significantly increased the levels of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) (P < 0.01, 0.001), and increased the release of lactate dehydrogenase (LDH) (P < 0.001). PVENs-Orl significantly induced a decrease in mitochondrial membrane potential (P < 0.01) and triggered mitochondrial dysfunction (P < 0.001). At the molecular mechanism level, PVENs-Orl upregulated the expressions of genes related to lipid peroxidation and ferroptosis promotion (P < 0.001), and downregulated the expressions of genes related to antioxidant and ferroptosis inhibition (P < 0.001). Conclusion PVENs could effectively deliver orlistat, disrupt lipid homeostasis by inhibiting FASN activity, induce mitochondrial dysfunction and lipid peroxidation, and synergistically regulate the expressions of key genes involved in ferroptosis, thereby inhibiting the growth of liver cancer cells. This provides experimental evidence for targeted lipid metabolism therapy based on natural exosomes.

liver cancer  /  Prunella vulgaris L.  /  exosomes  /  orlistat  /  lipid metabolism  /  ferroptosis