Srivastava M, Eidelman O, Pollard H B
Department of Anatomy and Cell Biology, and Institute for Molecular Medicine, USU School of Medicine, USUHS, Bethesda, MD 20814, USA.
Mol Med. 1999 Nov;5(11):753-67.
Cystic fibrosis (CF) is the most common lethal recessive disease affecting children in the U.S. and Europe. For this reason, a number of ongoing attempts are being made to treat the disease either by gene therapy or pharmacotherapy. Several phase 1 gene therapy trials have been completed, and a phase 2 clinical trial with the xanthine drug CPX is in progress. The protein coded by the principal CFTR mutation, DeltaF508-CFTR, fails to traffic efficiently from the endoplasmic reticulum to the plasma membrane, and is the pathogenic basis for the missing cAMP-activated plasma membrane chloride channel. CPX acts by binding to the mutant DeltaF508-CFTR and correcting the trafficking deficit. CPX also activates mutant CFTR channels. The comparative genomics of wild-type and mutant CFTR has not previously been studied. However, we have hypothesized that the gene expression patterns of human cells expressing mutant or wild-type CFTR might differ, and that a drug such as CPX might convert the mutant gene expression pattern into one more characteristic of wild-type CFTR. To the extent that this is true, a pharmacogenomic profile for such corrective drugs might be deduced that could simplify the process of drug discovery for CF.
To test this hypothesis we used cDNA microarrays to study global gene expression in human cells permanently transfected with either wild-type or mutant CFTR. We also tested the effects of CPX on global gene expression when incubated with cells expressing either mutant or wild-type CFTR.
Wild-type and mutant DeltaF508-CFTR induce distinct and differential changes in cDNA microarrays, significantly affecting up to 5% of the total genes in the array. CPX also induces substantial mutation-dependent and -independent changes in gene expression. Some of these changes involve movement of gene expression in mutant cells in a direction resembling expression in wild-type cells.
These data clearly demonstrate that cDNA array analysis of cystic fibrosis cells can yield useful pharmacogenomic information with significant relevance to both gene and pharmacological therapy. We suggest that this approach may provide a paradigm for genome-based surrogate endpoint testing of CF therapeutics prior to human administration.
囊性纤维化（CF）是美国和欧洲影响儿童的最常见致死性隐性疾病。因此，目前正在进行多项通过基因治疗或药物治疗来攻克该疾病的尝试。多项1期基因治疗试验已经完成，一项使用黄嘌呤药物CPX的2期临床试验正在进行中。由主要的CFTR突变DeltaF508 - CFTR编码的蛋白质无法有效地从内质网转运到质膜，这是缺失的cAMP激活的质膜氯离子通道的致病基础。CPX通过与突变的DeltaF508 - CFTR结合并纠正转运缺陷来发挥作用。CPX还能激活突变的CFTR通道。此前尚未对野生型和突变型CFTR的比较基因组学进行研究。然而，我们推测，表达突变型或野生型CFTR的人类细胞的基因表达模式可能存在差异，并且像CPX这样的药物可能会将突变基因表达模式转变为更具野生型CFTR特征的模式。如果确实如此，那么可以推导出此类纠正药物的药物基因组学特征，这可能会简化CF药物发现的过程。
为了验证这一假设，我们使用cDNA微阵列来研究永久转染野生型或突变型CFTR的人类细胞中的全局基因表达。我们还测试了CPX与表达突变型或野生型CFTR的细胞孵育时对全局基因表达的影响效。
野生型和突变型DeltaF508 - CFTR在cDNA微阵列中诱导出明显且不同的变化，显著影响了阵列中多达5%的总基因。CPX还诱导了大量依赖和不依赖突变的基因表达变化。其中一些变化涉及突变细胞中基因表达朝着类似于野生型细胞中表达的方向移动。
这些数据清楚地表明，对囊性纤维化细胞进行cDNA阵列分析能够产生与基因治疗和药物治疗均显著相关的有用药物基因组学信息。我们认为，这种方法可能为在人体给药前基于基因组的CF治疗替代终点测试提供一个范例。
