TRANSFECTION OF CDNAS FOR DRUG METABOLIZING ENZYMES

逆转录病毒载体已被用于稳定表达高水平的COX-1 或-2在C3H10T1/2和AS52细胞系中均有表达。在一系列 底物代谢研究表明，COX-1在这些细胞中能够更好地 代谢外源10fM花生四烯酸(AA)，而COX-2效果更好 能够利用佛波酯(TPA)释放的内源AA。两个人 异构体利用花生四烯酸的能力大致相同 由钙离子载体释放。在进一步的一系列实验中，它是 发现非甾体抗炎药对环氧合酶有不同程度的抑制作用 取决于AA的来源是内源还是外源。排名顺序 IC50比率(非甾体抗炎药对COX-2的抑制效力 相对于COX-1)与内源性释放的AA更接近 与非类固醇抗炎药的相对治疗/毒理作用相关 以外源AA为底物的比例高于活体比例。这些 细胞已被用来证明1，1-羟色胺的代谢活化。 二甲基肼、黄曲霉毒素B1和N-乙酰联苯胺。 来自合作研究的最新数据表明，通过 酚酞在表达COX-2的细胞中的表达，但在表达COX-2的细胞中不表达 COX-1。这些研究表明，有必要进行 在类似来源的整个细胞中进行代谢/抑制实验 能够持续高水平表达环氧合酶。

Retroviral vectors have been used to stably express high levels of COX-1 or -2 in both the C3H10T1/2 and AS52 cell lines. In a series of substrate metabolism studies, COX-1 in these cells was better able to metabolise exogenous 10fM arachidonic acid (AA), while COX-2 was better able to use the endogenous AA released by phorbol ester (TPA). The two isoforms were about equal in their ability to use arachidonic acid released by calcium ionophore. In a further series of experiments, it was found that NSAIDs differentially inhibit the cyclooxygenases depending upon the whether source of AA is endogenous or exogenous. The rank order of the IC50 ratios (the potency of inhibition by an NSAID for COX-2 relative to COX-1) with endogenously released AA were more closely correlated to the relative therapeutic/toxicologic effects of NSAIDs in vivo than were the ratios derived with exogenous AA as substrate. These cells have been used to demonstrate the metabolic activation of 1,1- dimethylhydrazine, aflatoxin B1, and N-acetylbenzidine by cyclooxygenase. Recent data from collaborative studies indicate a cytotoxic effect by phenolphthalein in COX-2 expressing cells, but not in those expressing COX-1. The studies demonstrate the need for conducting metabolism/inhibition experiments in whole cells of similar origin that are capable of sustained high levels of cyclooxygenase expression.