Real-time profiling of brazilin-induced cytotoxic responses in HepG2 cells and exosome-associated metabolic signaling under lipid accumulation

초록

Hepatocellular carcinoma (HCC) frequently arises in metabolically altered livers and often exhibits limited responses to systemic therapies, highlighting the need for agents that target both tumor cell survival and metabolic vulnerabilities. Brazilin, a bioactive compound from Caesalpinia sappan, has been reported to exert anticancer activities, yet its effects on intercellular communication under lipid-enriched conditions remain unclear. Here, we profiled brazilin-induced cytotoxic responses in HepG2 cells using real-time imaging-based monitoring of cell morphology, number, and area, together with viability assays. Brazilin reduced HepG2 viability in a concentration-dependent manner and suppressed pro-survival signaling (Akt phosphorylation and Bcl-2), accompanied by caspase-3 cleavage and increased Annexin V positivity, indicating apoptosis-associated cytotoxicity. We then isolated extracellular vesicles released from brazilin-treated HepG2 cells and confirmed exosome-like characteristics by TEM, exosomal marker expression (CD9/CD63/CD81), and nanoparticle tracking analysis. Notably, in palmitate/oleate-loaded HepG2 cells, exosomes derived from brazilin-treated cells modulated metabolic and stress-associated proteins, including reduced CPT1A and SOD1 levels and increased p27 expression, consistent with altered fatty-acid oxidation–related signaling under lipid accumulation. Collectively, these findings suggest that brazilin exerts direct cytotoxic effects in HepG2 cells and that exosomes released upon brazilin exposure may contribute to metabolic signaling changes in lipid-loaded cancer cells.

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