Endoplasmic reticulum stress contributes to autophagy and apoptosis in cantharidin-induced nephrotoxicity

Mylabris, as a natural product of traditional Chinese medicine (TCM), exhibiting typical antitumor activity, and cantharidin (CTD) is the major bioactive component. However, drug-induced nephrotoxicity (DIN) extremely limited its clinical application. In this study, we proved that activation of the endoplasmic reticulum (ER) stress dependent PERK/CHOP pathway exerts a toxic role in rats and HK-2 cells through inducing autophagy and apoptosis. Results showed that CTD could cause renal function damage, cytotoxicity, and apoptosis. The ER dilatation and autolysosomes were observed after CTD treatment. Furthermore, the distribution of LC3, ATF4, and CHOP proteins was observed in the nucleus and cytoplasm. In addition, the mRNA levels of ER stress regulated genes (PERK, eIF2 alpha, CHOP, and ATF4) were increased, and the expression levels of GRP78, ATF4, CHOP, LC3, Beclin-1, Atg3, Atg7, Caspase 3, and Bax/Bcl-2 proteins were increased both in vitro and in vivo. Consistently, this upregulation could be inhibited by an ER stress inhibitor 4-Phenylbutyric acid (4-PBA), indicating that ER stress is partly responsible for activation of autophagy and apoptosis in CTD-induced DIN. In conclusion, CTD could induce DIN by triggering ER stress, further activating autophagy and apoptosis both in vivo and in vitro.