Etoricoxib enhances aryl hydrocarbon receptor activity

Area of Science:

• Pharmacology
• Molecular Biology
• Biochemistry

Background:

• Etoricoxib is a selective cyclooxygenase-2 inhibitor NSAID with known cardiovascular concerns.
• The aryl hydrocarbon receptor (AhR) regulates xenobiotic metabolism and physiological functions.
• ITE is an endogenous AhR agonist that induces CYP1A1 expression.

Purpose of the Study:

• To investigate etoricoxib's interaction with the aryl hydrocarbon receptor (AhR) signaling pathway.
• To determine if etoricoxib modulates CYP1A1 expression.
• To explore potential synergistic effects between etoricoxib and ITE on AhR activity.

Main Methods:

• Cell-based assays using mouse Hepa-1c1c7 and human HepG2 cells.
• Measurement of CYP1A1 mRNA and protein expression.
• Assessment of AhR transcriptional activity via AHRE reporter assays.
• Inhibition studies using an AhR antagonist (CH-223191).

Main Results:

• Etoricoxib induced CYP1A1 mRNA and protein expression and AhR transcriptional activity in a dose-dependent manner.
• These effects were dependent on AhR signaling and inhibited by CH-223191.
• Etoricoxib promoted AhR translocation from the cytosol to the nucleus.
• Etoricoxib exhibited synergistic effects with ITE on CYP1A1 expression in human cells, particularly in those overexpressing AhR.

Conclusions:

• Etoricoxib acts as an AhR agonist in both mouse and human cells.
• Etoricoxib enhances ITE-induced CYP1A1 expression, suggesting a complex interplay within the AhR pathway.
• Further research on etoricoxib's effects on endothelial cells and cardiomyocytes is warranted to elucidate cardiovascular risks associated with COX-2 inhibitors.