Functional Analysis of Modified Caco-2 Cells Carrying CES2A1 as a Model for Intestinal Absorption of Prodrugs

Area of Science:

• Pharmacology
• Drug Metabolism
• Cell Biology

Background:

• Carboxylesterase (CES) enzymes are crucial for ester-containing prodrug metabolism.
• Human intestinal CES (CES2A1) and hepatic CES (CES1A) have distinct roles in prodrug activation.
• Caco-2 cells, a common model, have unsuitable CES1A/CES2A1 expression for prodrug studies.

Purpose of the Study:

• To characterize the metabolic and transport properties of a novel CES2/Caco-2^CES1KD cell line.
• To evaluate the suitability of this cell line for studying intestinal CES2A1-mediated prodrug hydrolysis.
• To compare CES2A1 activity in the new cell line with native human intestinal levels.

Main Methods:

• Development of CES2/Caco-2^CES1KD cells with reduced CES1A and enhanced CES2A1 expression.
• Analysis of CES and other drug-metabolizing enzyme/transporter expression.
• Assessment of ester hydrolysis using ethyl and butyl esters of p-aminobenzoic acid (PABA) across cell monolayers.

Main Results:

• CES2/Caco-2^CES1KD cells exhibited CES2A1 expression levels comparable to the human intestine.
• Butyl PABA, a CES2A1 substrate, showed significant hydrolysis in CES2/Caco-2^CES1KD cells, unlike in Caco-2 cells.
• Ethyl PABA hydrolysis was similar in both cell types, reflecting CES1A/CES2A1 substrate specificity.
• N-acetylation activity was comparable between Caco-2 and CES2/Caco-2^CES1KD cells.

Conclusions:

• The CES2/Caco-2^CES1KD cell line accurately models intestinal CES2A1 activity.
• This cell line is a valuable tool for investigating intestinal prodrug hydrolysis and absorption.
• It overcomes the limitations of Caco-2 cells for prodrug permeability studies.