Chelerythrine-Induced Apoptotic Cell Death in HepG2 Cells Involves the Inhibition of Akt Pathway and the Activation of Oxidative Stress and Mitochondrial Apoptotic Pathway

Abstract

Chelerythrine (CHE) is a majorly harmful isoquinoline alkaloid ingredient in Chelidonium majus that could trigger potential hepatotoxicity, but the pivotal molecular mechanisms remain largely unknown. In the present study, CHE-induced cytotoxicity and the underlying toxic mechanisms were investigated using human HepG2 cells in vitro. Data showed that CHE treatment (at 1.25–10 μM)-induced cytotoxicity in HepG2 cells is dose-dependent. CHE treatment increased the production of ROS and induced oxidative stress in HepG2 cells. Additionally, CHE treatment triggered the loss of mitochondrial membrane potential, decreased the expression of mitochondrial complexes, upregulated the expression of Bax, CytC, and cleaved-PARP1 proteins and the activities of caspase-9 and caspase-3, and downregulated the expression of Bcl-XL, and HO-1 proteins, finally resulting in cell apoptosis. N-acetylcysteine supplementation significantly inhibited CHE-induced ROS production and apoptosis. Furthermore, CHE treatment significantly downregulated the expression of phosphorylation (p)-Akt (Ser473), p-mTOR (Ser2448), and p-AMPK (Thr172) proteins in HepG2 cells. Pharmacology inhibition of Akt promoted CHE-induced the downregulation of HO-1 protein, caspase activation, and apoptosis. In conclusion, CHE-induced cytotoxicity may involve the inhibition of Akt pathway and the activation of oxidative stress-mediated mitochondrial apoptotic pathway in HepG2 cells. This study sheds new insights into understanding the toxic mechanisms and health risks of CHE.

Chelerythrine Chloride is an Affinity-Labeling Inactivator of CYP3A4 by Modification of Cysteine239

“…7 The iminium group of CHE is found to chemically reactive toward nucleophiles such as N-acetylcysteine (NAC). 8,9 The iminium form of CHE displays high affinity toward bovine hemoglobin relative to its alkanolamine form (another existence form of QBAs). 10 CHE is also a potent inhibitor of multiple enzymes such as protein kinase, acetylcholinesterase, and aromatic amino acid decarboxylase.…”

“…Due to these unique merits, CHE is commonly applied to health foods and animal feeds as a nutritional and functional additive . The iminium group of CHE is found to chemically reactive toward nucleophiles such as N -acetylcysteine (NAC). , The iminium form of CHE displays high affinity toward bovine hemoglobin relative to its alkanolamine form (another existence form of QBAs) . CHE is also a potent inhibitor of multiple enzymes such as protein kinase, acetylcholinesterase, and aromatic amino acid decarboxylase. − Dithiothreitol can reportedly prevent the irreversible inhibition of the decarboxylase mediated by CHE, suggesting the interaction between CHE and thiol group(s) of the enzyme involved in the inactivation mechanism …”