title: Transport and uptake of clausenamide enantiomers in CYP3A4-transfected Caco-2 cells: An insight into the efflux-metabolism alliance.
abstract: The present study developed a CYP3A4-expressed Caco-2 monolayer model at which effects of the efflux-metabolism alliance on the transport and uptake of clausenamide (CLA) enantiomers as CYP3A4 substrates were investigated. The apparent permeability coefficients (Papp) of (-) and (+)CLA were higher in the absorptive direction than those in the secretory direction with efflux ratios (ER) of 0.709±0.411 and 0.867±0.250 (×10(-6)cm/s), respectively. Their bidirectional transports were significantly reduced by 75.6-87.5% after treatment with verapamil (a P-glycoprotein inhibitor) that increased the rate of metabolism by CYP3A4, whereas the CYP3A4 inhibitor ketoconazole treatment markedly enhanced the basolateral to apical flux of (-) and (+)CLA with ERs being 2.934±1.432 and 1.877±0.148(×10(-6)cm/s) respectively. These changes could be blocked by the duel CYP3A4/P-glycoprotein inhibitor cyclosporine A, consequently, Papp values for CLA enantiomers in both directions were significantly greater than those obtained by using verapamil or ketoconazole, and their ERs were similar to those following (-) or (+)-isomer treatment alone. Furthermore, the uptake of (-)CLA was more than that of (+)CLA in the transfected cells. Incubation with ketoconazole decreased the intracellular concentrations of the two enantiomers. This effect disappeared in the presence of a CYP3A4 inducer dexamethasone. These results indicated that CYP3A4 could influence P-gp efflux, transport and uptake of CLA enantiomers as CYP3A4 substrates and that a duel inhibition to CYP3A4/ P-glycoprotein could enhance their absorption and bioavailability, which provides new insight into the efflux-metabolism alliance and will benefit the clinical pharmacology of (-)CLA as a candidate drug for treatment of Alzheimer's disease.
authors: Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors: Fang
authors: F
authors: Hua
authors: Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors: Mei-jun
authors: MJ
authors: Shi
authors: Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors: Xiao-lu
authors: XL
authors: Zhu
authors: Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors: Meng
authors: M
authors: Li
authors: Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
authors: Hong-xu
authors: HX
authors: Wang
authors: Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China; Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation, Beijing, China.
authors: Xiao-ming
authors: XM
authors: Yu
authors: Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China; Beijing Key Laboratory of Non-Clinical Drug Metabolism and PK/PD study, Beijing, China.
authors: Yan
authors: Y
authors: Li
authors: Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China; Beijing Key Laboratory of Non-Clinical Drug Metabolism and PK/PD study, Beijing, China; Beijing Key Laboratory of New Drug Mechanisms and Pharmacological Evaluation Study, Beijing, China. Electronic address: zhucj@imm.ac.cn.
authors: Chuan-jiang
authors: CJ
authors: Zhu
mesh_terms: D001692:Biological Transport; D018938:Caco-2 Cells; D003001:Cloning, Molecular; D051544:Cytochrome P-450 CYP3A / Q000235:genetics / Q000378:metabolism*; D018076:DNA, Complementary; D004305:Dose-Response Relationship, Drug; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007769:Lactams / Q000737:chemistry / Q000378:metabolism*; D017705:Lignans / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D014162:Transfection
chemical_list: D018076:DNA, Complementary; D007769:Lactams; D017705:Lignans; C053048:clausenamide; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human
keywords: Caco-2 cell line; Clausenamide; Cytochrome P450 3A4; Enantiomers; P-glycoprotein