Diverse action of acrylamide on cytochrome P450 and glutathione S-transferase isozyme activities, mRNA levels and protein levels in human hepatocarcinoma cells

Abstract

Humans are exposed to acrylamide in their diet and cigarette smoke. Acrylamide is metabolized into glycidamide by CYP2E1. However, very few studies regarding the effects of acrylamide on cytochrome P450 and Glutathione S-Transferase (GST) isozymes have been pursued. The aim of this study is to elucidate the effects of acrylamide on cytochrome P450 and GST isozymes in HepG2 cell line. Treatment with 1.25 and 2.5 mM acrylamide caused 9.5- and 3.7-fold increases and 4.0- and 3.3-fold increases in CYP1A-associated ethoxyresorufin O-deethylase (EROD) and methoxyresorufin O-demethylase (MROD) activities, respectively. These increases were consistent with increases in mRNA and protein levels of these isozymes. Similarly, CYP2E1-associated aniline 4-hydroxylase (ANH) activity, protein levels, and mRNA levels increased 2.1- and 2.6-fold, 2.4- and 3.2-fold, and 1.4- and 1.9-fold following 1.25 and 2.5 mM acrylamide treatments, respectively. In addition, GST-mu activity was increased 2.4- and 5.1-fold by acrylamide. Moreover, GST-mu mRNA and protein levels increased twofold as a result of acrylamide treatment. In contrast, GST-pi protein and mRNA levels decreased significantly. In conclusion, human cell exposure to acrylamide causes an increase in the levels of carcinogenicity and toxicity and a disturbance in drug metabolism, possibly due to complex effects on P450 and GST isozymes.

Dose-dependent synergistic and antagonistic mutation responses of binary mixtures of the environmental carcinogen benzo[a]pyrene with food-derived carcinogens

“…A recent study by Sen et al, (2012) showed AC induced EROD and MROD activities in HepG2 cells, however AC did not affect EROD in MCL-5 cells in the current study, nor was there any effect on BaP-induced EROD activity. However, it should be noted that this was following a 24h treatment in our study, whereas Sen et al (2012) used a 48h treatment. These results suggest that an alternative mechanism to one involving modulation of CYP2E1 activity is involved in the synergistic interaction, but more investigation is required to elucidate this.…”

“…While AC does require metabolic activation, this occurs via CYP2E1, and as such is not expected to be influenced by BaP. A recent study by Sen et al, (2012) showed AC induced EROD and MROD activities in HepG2 cells, however AC did not affect EROD in MCL-5 cells in the current study, nor was there any effect on BaP-induced EROD activity. However, it should be noted that this was following a 24h treatment in our study, whereas Sen et al (2012) used a 48h treatment.…”

Interactions between dietary acrylamide intake and genes for ovarian cancer risk

“…Conjugation of acrylamide with GSH can result in depletion of cellular GSH stores, leading to altered gene expression directly or through regulating various redox-dependent transcription factors [7]. Considering the fact that acrylamide induces GST activity [25, 26], it would be expected that the positive association between acrylamide and ovarian cancer is only present among women with at least one copy of the genes in whom the activity of GST can be induced.…”

Scientific Opinion on acrylamide in food

“…In order to study whether AA itself could induce CYPs, cultured human HepG2 cells, which are derived from a hepatic adenocarcinoma, were treated with 1.25 and 2.5 mM AA (Sen et al, 2012). A 2.0-2.6-fold, 2.4-3.2-fold, and 1.4-1.9-fold increase in CYP2E1-associated enzyme activity, protein level and m-RNA level, respectively, was observed.…”

“…Data on the induction of GSTs by AA are also very rare. Sen et al (2012) studied the effects of AA at 1.25 mM and 2.5 mM concentration on the activity and expression of GST-mu and GST-pi isozymes in cultured HepG2 cell. A slight induction (2.0-5.1-fold, depending on the endpoint) was observed for GST-mu, whereas the activity and expression of GST-pi were reduced.…”