Modifying rates of reductive elimination of leaving groups from indolequinone prodrugs: a key factor in controlling hypoxia-selective drug release
作者:Steven A. Everett、Elizabeth Swann、Matthew A. Naylor、Michael R.L. Stratford、Kantilal B. Patel、Natasha Tian、Robert G. Newman、Borivoj Vojnovic、Christopher J. Moody、Peter Wardman
DOI:10.1016/s0006-2952(02)00885-7
日期:2002.5
Rates of reductive release of the fluorophore from the non-fluorescent parent indolequinones (R=H, Me, thienyl) were similar under anoxia ( approximately 1.7 nmol coumarinmin(-1)mg protein(-1)) reflecting the similarity in one-electron reduction potential. Whereas coumarin release from the indolequinone (R=H) was completely inhibited above 0.5% O2, the enhanced rate of reductive elimination when R=thienyl
合成3-(4-甲基香豆素-7-酰氧基)甲基吲哚-4,7-二酮作为模型前药,以研究(吲哚基-3-基)甲基位置的还原消除速率与低氧引起的还原代谢之间的相关性肿瘤细胞和NADPH:细胞色素P450。通过使用分光光度法和荧光检测的脉冲辐射分解法测定吲哚醌被单电子还原为半醌自由基(Q *-)后发色团/荧光团(7-羟基-4-甲基香豆素)的消除速率。在(吲哚-3-基)CHR位上掺入噻吩基或甲基取代基(其中R =与酚醚连接键相邻的噻吩基或甲基)显着缩短了还原消除的半衰期,从87毫秒缩短至6毫秒和2毫秒, 分别。因此,消除甲基取代的类似物可以有效地竞争半醌自由基与氧气在肿瘤中通常存在的水平下发生反应(在0.5%的O2下,半衰期约为1.8毫秒)。化学动力学预测已通过在0-2.1%O2之间的乳腺肿瘤MCF-7细胞中的代谢来证实。在缺氧条件下,非荧光母体吲哚醌(R = H,Me,噻吩基)的荧光团还原释放速率相似(约1