作者:Clinton R. Nishida、Melody Lee、Paul R. Ortiz de Montellano
DOI:10.1124/mol.110.065045
日期:2010.9
AQ4N [1,4-bis[2-(dimethylamino- N -oxide)ethyl]amino}-5,8-dihydroxyanthracene-9,10-dione], a prodrug with two dimethylamino N -oxide groups, is converted to the topoisomerase II inhibitor AQ4 [1,4-bis[2-(dimethylamino)ethyl]amino}-5,8-dihydroxy-anthracene-9,10-dione] by reduction of the N -oxides to dimethylamino substituents. Earlier studies showed that several drug-metabolizing cytochrome P450 (P450) enzymes can catalyze this reductive reaction under hypoxic conditions comparable with those in solid tumors. CYP2S1 and CYP2W1, two extrahepatic P450 enzymes identified from the human genome whose functions are unknown, are expressed in hypoxic tumor cells at much higher levels than in normal tissue. Here, we demonstrate that CYP2S1, contrary to a published report ( Mol Pharmacol 76: 1031–1043, 2009), is efficiently reduced by NADPH–P450 reductase. Most importantly, both CYP2S1 and CYP2W1 are better catalysts for the reductive activation of AQ4N to AQ4 than all previously examined P450 enzymes. The overexpression of CYP2S1 and CYP2W1 in tumor tissues, together with their high catalytic activities for AQ4N activation, suggests that they may be exploited for the localized activation of anticancer prodrugs.
AQ4N [1,4-双[2-(二甲氨基-N-氧化物)乙基]氨基}-5,8-二羟基蒽-9,10-二酮],一种具有两个二甲氨基N-氧化物基团的前药,被转化为拓扑异构酶 II 抑制剂 AQ4 [1,4-双[2-(二甲氨基)乙基]氨基}-5,8-二羟基-蒽-9,10-二酮]通过将 N-氧化物还原为二甲氨基取代基。早期研究表明,几种药物代谢细胞色素 P450 (P450) 酶可以在与实体瘤中类似的缺氧条件下催化这种还原反应。 CYP2S1和CYP2W1是从人类基因组中鉴定出的两种功能未知的肝外P450酶,它们在缺氧肿瘤细胞中的表达水平比正常组织中高得多。在这里,我们证明,与已发表的报告(Mol Pharmacol 76:1031-1043,2009)相反,CYP2S1 可以被 NADPH-P450 还原酶有效还原。最重要的是,与之前研究的所有 P450 酶相比,CYP2S1 和 CYP2W1 都是 AQ4N 还原活化为 AQ4 的更好催化剂。 CYP2S1和CYP2W1在肿瘤组织中的过度表达,以及它们对AQ4N激活的高催化活性,表明它们可用于抗癌前药的局部激活。