Glutathione S-Transferase P1 Protects Against Amodiaquine Quinoneimines-Induced Cytotoxicity but Does Not Prevent Activation of Endoplasmic Reticulum Stress in HepG2 Cells

Abstract

Formation of the reactive amodiaquine quinoneimine (AQ-QI) and N-desethylamodiaquine quinoneimine (DEAQ-QI) plays an important role in the toxicity of the anti-malaria drug amodiaquine (AQ). Glutathione conjugation protects against AQ-induced toxicity and GSTP1 is able to conjugate its quinoneimine metabolites AQ-QI and DEA-QI with glutathione. In this study, HepG2 cells transiently transfected with the human GSTP1 construct were utilized to investigate the protective effect of GSTP1 in a cellular context. HepG2 cells were exposed to synthesized QIs, which bypasses the need for intracellular bioactivation of AQ or DEAQ. Exposure was accompanied by decreased cell viability, increased caspase 3 activity, and decreased intracellular GSH levels. Using high-content imaging-based BAC-GFP reporters, it was shown that AQ-QI and DEAQ-QI specifically activated the endoplasmic reticulum (ER) stress response. In contrast, oxidative stress, DNA damage, or inflammatory stress responses were not activated. Overexpression of GSTP1 resulted in a two-fold increase in GSH-conjugation of the QIs, attenuated QI-induced cytotoxicity especially under GSH-depletion condition, abolished QIs-induced apoptosis but did not significantly inhibit the activation of the ER stress response. In conclusion, these results indicate a protective role of GSTP1 by increasing enzymatic detoxification of AQ-QI and DEAQ-QI and suggest a second protective mechanism by interfering with ER stress induced apoptosis.

The antimalarial drug amodiaquine stabilizes p53 through ribosome biogenesis stress, independently of its autophagy-inhibitory activity

“…6d), probably corresponding to AQglutathione adducts, the detoxification product catalyzed by glutathione S-transferases. This reaction is observed for AQ and reactive metabolites derived from other drugs [53]. Importantly, the absence of the reactive group in DH-AQ completely abrogated the formation of protein adducts, however, DH-AQ still triggered RPA194 degradation in U2OS cells and weaker p53 activation in both cell lines.…”

Mechanistic Study of Icaritin-Induced Inactivation of Cytochrome P450 2C9

“…The minor loss of enzyme activity in the NADPH-absent samples implied the presence of spontaneous bioactivation and/or oxidative enzymes other than P450s involving in the inactivation of CYP2C9. Human GSTs were reported to be protective enzymes catalyzing the inactivation of reactive metabolites derived from various drugs causing toxicities (Dekker et al, 2016;den Braver et al, 2016;Zhang et al, 2018). The individual expression level of human hepatic GSTs was varying a lot (den , which reflecting a varying inactivation profile towards reactive drug metabolites (den Braver et al, 2016, Zhang et al, 2017.…”

Mesenchymal Stromal Cell-Derived Extracellular Vesicles Restore Thymic Architecture and T Cell Function Disrupted by Neonatal Hyperoxia

“…Interestingly, both MEx-modulated DC clusters and mTECs exhibited increased expression of Gstp1 gene. This gene encodes an enzyme that has a critical role in decreasing oxidative damage in cells by scavenging the reactive oxygen species (ROS) to glutathione which then eliminates these toxic compounds (58). Effects of EVs on ROS scavenging and detoxification has been previously demonstrated by various groups, and these vesicles have been shown to either carry different antioxidant enzymes such as glutathione peroxidase (GPX), glutathione S-transferase (GST) or catalase (CAT) (59)(60)(61) or to contain the necessary enzymatic machinery to activate antioxidant pathways (62).…”