Activation of HSPA5 contributes to pazopanib-induced hepatotoxicity through l-ornithine metabolism pathway and endoplasmic reticulum stress.

Objectives: The clinical application of Pazopanib (Paz) is often accompanied by hepatotoxicity. However, the mechanisms of hepatic toxicity induced by pazopanib are not entirely clarified.

Methods: Male C57BL/6J mice were treated with pazopanib every day for 2, 4, or 8 weeks. Transcriptomics and metabolomics analyses of liver tissues were performed. In vitro experiments were carried out to estimate cell viability, apoptosis, and autophagy in L02 cells after Paz treatment. We also examined apoptosis and autophagy-related genes under 4-PBA, l-ornithine, nor-NOHA treatments, and HSPA5 knockdown.

Key findings: Repeated Paz treatment for 8 weeks resulted in more severe hypofunction of the liver in mice. Moreover, Paz treatment inhibited L02 cells cell viability in a dose-dependent manner. We also discovered activation of endoplasmic reticulum stress, apoptosis, and autophagy in Paz-treated L02 cells, as evidenced by the boosted expression of HSPA5, p-IRE1α, ATF4, ATF6, p-eIF2α, LC3, Beclin-1, and a decrease of phosphorylated PI3K, AKT, and mTOR levels. Moreover, 4-PBA, l-ornithine, and HSPA5 knockdown inhibited apoptosis and autophagy, while nor-NOHA weakened the effects of HSPA5 knockdown on apoptosis in Paz-treated L02 cells.

Conclusions: In summary, our study revealed that Paz-induced liver toxicity is related to HSPA5 expression and l-ornithine metabolism pathway in mice.