Fluoxetine reduces CES1, CES2, and CYP3A4 expression through decreasing PXR and increasing DEC1 in HepG2 cells

Area of Science:

• Pharmacology
• Hepatology
• Drug Metabolism

Background:

• Fluoxetine (FLX) is a widely used antidepressant.
• Carboxylesterases (CES) and cytochrome P450 3A4 (CYP3A4) are crucial enzymes in drug metabolism.
• Understanding FLX's impact on these enzymes is vital for patient safety.

Purpose of the Study:

• To elucidate the molecular mechanisms by which FLX affects CES and CYP3A4 expression and activity in HepG2 cells.
• To investigate the roles of pregnane X receptor (PXR) and differentiated embryonic chondrocyte-expressed gene 1 (DEC1) in mediating these effects.

Main Methods:

• Utilized HepG2 cell line for in vitro studies.
• Assessed gene and protein expression levels of CES1, CES2, CYP3A4, PXR, and DEC1.
• Measured CES hydrolytic activity.
• Employed gene overexpression and knockdown techniques for PXR and DEC1.

Main Results:

• FLX significantly decreased CES1, CES2, and CYP3A4 expression and activity.
• FLX reduced PXR expression transcriptionally while increasing DEC1 expression.
• PXR manipulation directly altered CES and CYP3A4 levels, while DEC1 knockdown reversed FLX-induced decreases.
• FLX-induced reduction in CES and CYP3A4 is mediated by decreased PXR and increased DEC1.

Conclusions:

• FLX exerts its inhibitory effects on CES and CYP3A4 through a mechanism involving the downregulation of PXR and upregulation of DEC1.
• These findings provide critical insights into the drug-drug interaction potential of FLX and its impact on hepatic enzyme activity.