One of the leading therapies for acute lymphoblastic leukemia (ALL) is the chemotherapeutic agent PEGylated E. coli-derived-l-asparaginase (PEG-ASNase). Due to the high risk of dose-limiting liver injury, characterized by clinically elevated levels of hepatic transaminases, PEG-ASNase therapy is generally avoided in adult patients. Our preclinical investigations have indicated that PEG-ASNase-induced liver injury is associated with the release of free fatty acids (FFAs) from white adipose tissue (WAT), suggesting potential lipotoxic effects. However, it remains uncertain whether PEG-ASNase directly induces hepatotoxicity or sensitizes hepatocytes to FFA-induced toxicity. Our results show that PEG-ASNase treatment results in hepatocyte apoptosis and lipid peroxidation. Ex vivo and in vitro studies in mouse and human WAT suggest that PEG-ASNase induces the expression of adipose triglyceride lipase (ATGL), activates the lipase, and stimulates adipose tissue lipolysis, suggesting that the FFAs from WAT may contribute to the observed liver injury. Moreover, treatment with PEG-ASNase sensitizes hepatocytes to FFA-induced lipotoxicity. Mechanistically, our RNA-sequencing (RNA-seq) analyses reveal that PEG-ASNase-induced sensitization to lipotoxicity is accompanied by the induction of Cyp2e1. We demonstrated that this sensitization effect is attenuated by both pharmacological and genetic inhibition of Cyp2e1. Our findings suggest that PEG-ASNase therapy induces WAT lipolysis and sensitizes hepatocytes to hepatic lipotoxicity in a Cyp2e1-dependent manner.

PEGylated-l-asparaginase (PEG-ASNase) is a chemotherapeutic agent used to treat pediatric acute lymphoblastic leukemia (ALL). Its use is avoided in adults due to its high risk of liver injury including hepatic steatosis, with obesity and older age considered risk factors of the injury. Our study aims to elucidate the mechanism of PEG-ASNase-induced liver injury. Mice received 1500 U/kg of PEG-ASNase and were sacrificed 1, 3, 5, and 7 days after drug administration. Liver triglycerides were quantified, and plasma bilirubin, ALT, AST, and non-esterified fatty acids (NEFA) were measured. The mRNA and protein levels of genes involved in hepatic fatty acid synthesis,