Cantharidin-induced LO2 cell autophagy and apoptosis via endoplasmic reticulum stress pathway in vitro

Cantharidin (CTD), an important active compound derived from the traditional Chinese medicine Mylabris (also called Banmao), has been used in the treatment of diseases such as tumors and dermatosis. However, Mylabris has been shown to induce hepatotoxicity in clinical practice and animal experiments, limiting its use. Further, a detailed mechanism underlying CTD-induced hepatotoxicity has not been determined. In the present study, we aimed to explore the effect of endoplasmic reticulum stress (ERS), autophagy, and apoptosis on CTD-induced hepatotoxicity. We found that CTD could inhibit the proliferation of LO2 cells; increase alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and malondialdehyde levels; and reduce glutathione peroxidase and superoxide dismutase activities. Western blotting showed that low concentrations of CTD induced the expressions of ERS-related proteins GRP78, ATF4, PERK, p-PERK, XBP1–1 s, and CHOP], but high concentrations of CTD inhibited their expressions. Furthermore, high concentrations of CTD activated autophagy (LC3, Beclin-1, Atg3, Atg4A, Atg4B, and Atg7), induced the expressions of apoptotic proteins (Bax/Bcl-2 and caspase-3), and increased LO2 toxicity. Taken together, these results indicated that CTD can induce LO2 cytotoxicity by inhibiting ERS and inducing autophagy and apoptosis, which provides a scientific basis for CTD-induced hepatotoxicity.