S-Allylcysteine Potently Protects against PhIP-Induced DNA Damage via Nrf2/AhR Signaling Pathway Modulation in Normal Human Colonic Mucosal Epithelial Cells

Abstract

Scope: This study aims to investigate whether S-allylcysteine (SAC) exerts chemoprophylactic effects on foodborne carcinogenicity caused by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in normal human colonic mucosal epithelial cells.

Methods and results: Cellular thermal shift assays show that SAC has an affinity for the Kelch-like ECH-associated protein 1 (Keap1) protein. Moreover, SAC may also dampen the binding of Keap1 and NF-E2-related factor 2 (Nrf2) by inhibiting p-p38 and increasing the phosphorylation of extracellular signal regulated kinases 1/2 (ERK1/2) and protein kinase B (AKT), thereby inducing Nrf2/heme oxygenase-1 (HO-1) signaling and upregulating the ratio of glutathione (GSH) to GSH/GSSG (oxidized glutathione), which inhibits PhIP-induced oxidative stress and DNA damage. In addition, SAC significantly downregulates the aryl hydrocarbon receptor signaling pathway, suggesting that SAC may potentially impede the metabolic transformation of carcinogens.

Conclusion: Collectively, these findings suggest that SAC protects against PhIP-induced reactive oxygen species production and DNA damage by modulating the Nrf2/AhR signaling pathway, which may have significant potential as a novel chemopreventive agent.

Keywords: Nrf2/AhR; PhIP; S-allylcysteine; chemoprevention; normal colonic epithelia cells.