D'Elia Paolo, De Matteis Francesco, Dragoni Stefania, Shah Anamik, Sgaragli Giampietro, Valoti Massimo
Department of Neurosciences, University of Siena, Siena, Italy.
Eur J Pharmacol. 2009 Jul 1;614(1-3):7-13. doi: 10.1016/j.ejphar.2009.04.019. Epub 2009 Apr 18.
The aim of this study was to investigate the effects of 3,5-dibenzoyl-4-(3-phenoxy-phenyl)-1,4-dihydro-2,6-dimethylpyridine (DP7), a novel multidrug resistance (MDR) reverter, on cytochrome P450 (CYP)-activities by human and rat liver microsomes. Effects of DP7 were assessed with use of selective substrates, markers of CYP activities. With rat microsomes, ethoxyresorufin (ETR) was used as substrate for CYP1A1, penthoxyresorufin (PTR) for 2B, benzyloxyresorufin (BZR) for 1A1/2, 2B, 2C, 3A. CYP3A enzyme activities of rat (3A2) and human (3A4) liver microsomes, were assessed fluorimetrically using either 7-benzyloxy-quinoline (BQ) or [3-[3(3,4-difluorobenzyl)oxy]-5,5-dimethyl-4-[4-(methylsulfonyl)-phenyl]furan-2-(5H)-one] (DFB). When rat microsomes were incubated with DP7, concentration-inhibition curves were obtained. DP7 inhibitions gave IC(50) values of 3.8 microM for PTR, 3.8 microM for ETR and 10.4 microM for BZR and were not competitive in nature; moreover, they were reversible. When BQ was used as substrate of rat microsomes, DP7 inhibited its oxidation with an IC(50) value of 4.17 microM, while this oxidation was inhibited by only 25% at the highest DP7 concentration used (75 microM) with human microsomes. On the contrary, when DFB was used as substrate, DP7 showed identical IC(50) values (34.67 microM) with microsomal preparations from either species. The moderate inhibition of CYP isoforms of rat liver microsomes and the weak inhibition of human CYP3A4 enzyme activity operated by DP7, suggest that DP7 in man should not give rise to important, unpredictable pharmacokinetic interactions. This conclusion supports the role of this compound as a lead for the development of novel MDR reverterting dihydropyridines of therapeutic interest.
本研究旨在探讨新型多药耐药（MDR）逆转剂3,5-二苯甲酰基-4-（3-苯氧基苯基）-1,4-二氢-2,6-二甲基吡啶（DP7）对人及大鼠肝微粒体细胞色素P450（CYP）活性的影响。使用CYP活性的选择性底物、标志物来评估DP7的作用。对于大鼠微粒体，乙氧基试卤灵（ETR）用作CYP1A1的底物，戊氧基试卤灵（PTR）用作2B的底物，苄氧基试卤灵（BZR）用作1A1/2、2B、2C、3A的底物。大鼠（3A2）和人（3A4）肝微粒体的CYP3A酶活性，使用7-苄氧基喹啉（BQ）或[3-[3(3,4-二氟苄基)氧基]-5,5-二甲基-4-[4-(甲基磺酰基)-苯基]呋喃-2-(5H)-酮]（DFB）通过荧光法进行评估。当大鼠微粒体与DP7一起孵育时，获得了浓度抑制曲线。DP7对PTR的抑制IC(50)值为3.8 microM，对ETR为3.8 microM，对BZR为10.4 microM，且本质上无竞争性；此外，这些抑制是可逆的。当BQ用作大鼠微粒体的底物时，DP7抑制其氧化，IC(50)值为4.17 microM，而在使用的最高DP7浓度（75 microM）下，人微粒体的这种氧化仅被抑制25%。相反，当DFB用作底物时，DP7对两种物种的微粒体制剂显示出相同的IC(50)值（34.67 microM）。DP7对大鼠肝微粒体CYP同工型的适度抑制以及对人CYP3A4酶活性的微弱抑制表明，DP7在人体中不应引起重要的、不可预测的药代动力学相互作用。这一结论支持了该化合物作为开发具有治疗意义的新型MDR逆转二氢吡啶的先导化合物的作用。
