Transport and metabolic characterization of Caco-2 cells expressing CYP3A4 and CYP3A4 plus oxidoreductase.
OBJECTIVE
To further characterize CYP3A4-transfected Caco-2 cells with regard to morphological, transport, and metabolic properties, and to evaluate a different Caco-2 cell strain transfected with both CYP3A4 and oxidoreductase (OR).


METHODS
Transfected Caco-2 cells, Caco-2 TC7 cells, and wild-type Caco-2 cells grown onto Millicell were used. We determined the morphological characteristics of transfected cell monolayers using light and transmission electron microscope. We determined the transport and metabolic capabilities of the transfected cells, TC7 cells, and wild-type cells with a variety of drugs, nutrients, and marker compounds.


RESULTS
The transfected Caco-2 cells formed a tight monolayer with TEER values and mannitol transport similar to the untransfected parent cell strain (wild type). However, the transfected cells (grown onto Millicell) reached maturity approximately 33% faster than the wild-type cells. Permeabilities of propranolol, nifedipine, testosterone, linopirdine, mannitol, and cephalexin were similar in transfected and wild-type Caco-2 cells. On the other hand, the transfected cells of early passages were much more metabolically active, and metabolized standard CYP3A4 substrates (e.g., testosterone and nifedipine) as much as 100 times faster than untransfected cells. In addition, metabolism of standard substrates was inhibitable by ketoconazole and TAO. Using comparable data, the transfected cells metabolized testosterone the fastest, followed by linopirdine and nifedipine (approximate ratio: 10:6:2). The metabolites of standard substrates were generally preferably excreted to the apical membrane.


CONCLUSIONS
The monolayers of newly transfected cells (CYP3A4 + OR) have a significantly increased level of CYP3A4 activities compared to untransfected cells. These cell monolayers also have desirable morphological and transport characteristics that are similar to untransfected cells.
Hu
M
M
Department of Pharmaceutical Sciences, College of Pharmacy, Washington State University, Pullman 99164-6510, USA. minghu@wsu.edu
Li
Y
Y
Davitt
C M
CM
Huang
S M
SM
Thummel
K
K
Penman
B W
BW
Crespi
C L
CL
D000925:Anticoagulants / Q000493:pharmacokinetics; D018931:Antineoplastic Agents, Hormonal / Q000493:pharmacokinetics; D001692:Biological Transport; D018938:Caco-2 Cells / Q000201:enzymology* / Q000648:ultrastructure; D002121:Calcium Channel Blockers / Q000493:pharmacokinetics; D002273:Carcinogens / Q000494:pharmacology; D002455:Cell Division / Q000502:physiology; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D004234:Diuretics, Osmotic / Q000493:pharmacokinetics; D018757:GABA Modulators / Q000493:pharmacokinetics; D015971:Gene Expression Regulation, Enzymologic; D005822:Genetic Vectors; D006801:Humans; D007211:Indoles / Q000737:chemistry / Q000378:metabolism; D008324:Mammary Tumor Virus, Mouse; D008353:Mannitol / Q000493:pharmacokinetics; D008854:Microscopy, Electron; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism; D008874:Midazolam / Q000493:pharmacokinetics; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism*; D009543:Nifedipine / Q000493:pharmacokinetics; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D011433:Propranolol / Q000493:pharmacokinetics; D011725:Pyridines / Q000737:chemistry / Q000378:metabolism; D013565:Sympatholytics / Q000493:pharmacokinetics; D013739:Testosterone / Q000493:pharmacokinetics; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection; D014316:Tritium; D014859:Warfarin / Q000493:pharmacokinetics
D000925:Anticoagulants; D018931:Antineoplastic Agents, Hormonal; D002121:Calcium Channel Blockers; D002273:Carcinogens; D004234:Diuretics, Osmotic; D018757:GABA Modulators; D007211:Indoles; D011725:Pyridines; D013565:Sympatholytics; D014316:Tritium; D008353:Mannitol; D013739:Testosterone; D014859:Warfarin; D003577:Cytochrome P-450 Enzyme System; D011433:Propranolol; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; C061017:linopirdine; D009543:Nifedipine; D013755:Tetradecanoylphorbol Acetate; D008874:Midazolam