Extracellular Vesicle-Packaged ACSL4 Induces Hepatocyte Senescence to Promote Hepatocellular Carcinoma Progression.

Extracellular vesicles (EV) derived from cancer cells are crucial mediators of intercellular communication during tumor progression. The cargo in tumor-derived EVs that facilitates the establishment of a tumor-supportive microenvironment could serve as a therapeutic target to improve cancer treatment. Here, we demonstrated that hepatocellular carcinoma (HCC) cells secreted the acyl-CoA synthetase long-chain family member 4 (ACSL4) in large EVs (lEV) to modulate tumor-microenvironment interactions that promote HCC progression. HCC-derived lEV ACSL4 increased the intracellular abundance of polyunsaturated fatty acid-containing lipids and remodeled the lipid profile to potentiate lipid peroxidation in peritumoral hepatocytes, resulting in hepatocyte senescence accompanied by the senescence-associated secretory phenotype. Depletion of senescent hepatocytes by senolytic treatment suppressed tumor progression. In HCC cells, SREBP2-mediated transcriptional activation upregulated ACSL4 expression, and Akt-mediated phosphorylation of ACSL4 induced its packaging into lEVs by augmenting its interaction with Annexin A2. This study identified the critical regulatory function of ACSL4 secreted from HCC cells in inducing lipid remodeling and senescence in hepatocytes to support HCC progression, suggesting that targeting lEV ACSL4 is a potential therapeutic strategy for HCC. Significance: Peritumoral hepatocyte senescence mediated by ACSL4 secreted from hepatocellular carcinoma cells in extracellular vesicles promotes tumor progression through a senescence secretome and represents a therapeutic target in liver cancer.