Organ-specific Ugt1 profiling in detoxifying the anticancer drug CPT-11

抗癌药物 CPT-11 解毒过程中的器官特异性 Ugt1 分析

• 批准号: 8507662
• 负责人: Shujuan Chen
• 金额: $ 15.84万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-09 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8507662
• 关键词: Active Biological Transport; Adverse effects; Alleles; Animal Model; Antineoplastic Agents; Benefits and Risks; Benign; Beta-glucuronidase; Biliary; Carboxylic Ester Hydrolases; Cells; Clinical Research; Colon; Colon Carcinoma; Colorectal Cancer; Development; Diarrhea; Diffusion; Dose; Drug Kinetics; Drug Metabolic Detoxication; Drug Tolerance; Duct (organ) structure; Enzymes; Epigenetic Process; Epithelial Cells; Etiology; Event; Exhibits; Extrahepatic; Gastrointestinal tract structure; Gene Deletion; Gene Expression; Genes; Genetic; Genetic Variation; Glucuronides; Hepatic; High Pressure Liquid Chromatography; Human; In Vitro; Individual; Inherited; Intestines; Knockout Mice; Label; Laboratories; Laboratory Study; Ligands; Liver; Malignant - descriptor; Maximum Tolerated Dose; Metabolism; Modeling; Monitor; Mus; Neutropenia; Nuclear Receptors; Organ; Patients; Pattern; Pharmaceutical Preparations; Plasma; Play; Prodrugs; Protein Isoforms; Proteins; Resistance; Risk; Role; SN-38; Safety; Therapeutic; Therapeutic Index; Tissue Therapy; Tissues; Topoisomerase; Toxic effect; Treatment Efficacy; Tumor Tissue; UGT1A1 gene; UGT1A8 UDP-glucuronosyltransferase; Up-Regulation; Update; bilirubin uridine-diphosphoglucuronosyl transferase 1A10; cancer diagnosis; cancer therapy; carboxylesterase; cytotoxicity; gastrointestinal; improved; inhibitor/antagonist; irinotecan; metastatic colorectal; mouse model; novel; overexpression; prevent; protein expression; recombinase; research study; response; therapeutic target; trend; tumor; tumorigenesis; tumorigenic

DESCRIPTION (provided by applicant): Irinotecan (CPT-11) has been used as a first line drug in the treatment of colorectal cancer, the third most commonly diagnosed cancer in the world. However, its efficacy and safety is compromised because of severe neutropenia and late diarrhea, the side-effects resulting from CPT-11 bioactivation and subsequent metabolism. CPT-11 is a prodrug that is hydrolyzed by carboxylesterase to the active topoisomerase 1 inhibitor, SN-38. Inactivation and detoxification occurs primarily by UGT1A1 catalyzed glucuronidation to form SN-38 glucuronide (SN-38G). SN-38G is excreted via the biliary ducts into the gastrointestinal (GI) tract, where it serves as a substrate for bacterial ?-glucuronidase enzymes produced by microflora. Free SN-38 is absorbed into the GI tract through passive diffusion or active transport. In 2005 and 2010, the FDA updated the label for CPT-11 regarding the heightened risk of serious side effects for patients that inherit the UGT1A1*28 allele and exhibit reduced expression of UGT1A1. However, several recent clinical studies summarize a trend of improved survival and statistically significant higher tumor response rates among individuals that are homozygous for the UGT1A1*28 allele. It is important to fully understand the association between SN-38 directed glucuronidation and the pending intestinal tissue damage resulting from CPT-11 therapy. Recently, we have generated an Ugt1 conditional knockout mouse model targeting deletion of the Ugt1 locus specifically in liver tissue (Ugt1?Hep mice). Surprisingly, even with the complete absence of the hepatic Ugt1 locus and all UGT1A proteins, Ugt1DHep mice are quite resistant towards CPT-11 treatment and the ensuing intestinal tract toxicity. Thus, we hypothesize that extrahepatic expression of the UGT1A proteins contributes to the detoxification of SN-38, which can be further confirmed in mice following gastrointestinal tract deletion of the Ugt1 locus (Ugt1?GI mice). Importantly, we speculate that GI tract directed control of the Ugt1 locus in mice can be leveraged to directly examine the contribution of this tissue towards SN-38 elicited intestinal damage. To examine the contribution of tissue specific expression of the Ugt1 locus in mice towards CPT-11 initiated intestinal damage, we will perform the following experiments. Specific Aim 1 will be directed to determine the impact of organ specific deletion of the Ugt1 locus in CPT-11 delayed diarrhea. Studies outlined under this aim will explore differences in CPT-11 induced intestinal toxicity in both Ugt1?Hep and Ugt1?GI mice. Specific Aim 2 will examine the impact of inducing selectively intestinal UGT1A1 expression and its enhanced contribution towards protecting intestinal tissue from the toxic insult generated from increasing concentrations of SN-38. With novel animal models recently developed in our laboratory, these studies will identify the role of hepatic and intestinal glucuronidation towards the etiology of CPT-11 induced intestinal toxicity. These models can be exploited to identify therapeutics that will improve the therapeutic index and efficacy associated with CPT-11 treatment.

描述（由申请人提供）：Irinotecan（CPT-11）已被用作治疗结直肠癌的第一行药物，这是世界上第三大常见的癌症。然而，由于严重的中性粒细胞减少症和晚期腹泻，其功效和安全性受到损害，这是CPT-11生物活化和随后的代谢引起的副作用。 CPT-11是一种前药，被羧酸酯酶水解为活性拓扑异构酶1抑制剂SN-38。失活和解毒主要是由UGT1A1催化的葡萄糖醛酸化而发生的，形成SN-38葡萄糖醛酸糖苷（SN-38G）。 SN-38G通过胆道导管排出胃肠道（GI），在那里它用作细菌的底物？ - 葡萄糖醛酸苷酶酶由微生物产生。自由SN-38通过被动扩散或主动转运吸收到胃肠道中。在2005年和2010年，FDA更新了CPT-11的标签，内容涉及继承UGT1A1*28等位基因并显示出UGT1A1表达降低的患者的严重副作用风险的增加。然而，最近的一些临床研究总结了提高生存率和统计学上显着较高的肿瘤反应率的趋势，而对于UGT1A1*28等位基因是纯合子的趋势。重要的是要充分了解SN-38定向葡萄糖醛酸化与CPT-11治疗导致的肠道组织损伤之间的关联。最近，我们已经生成了一个有条件的敲除小鼠模型，该模型针对肝组织中的UGT1基因座的缺失（UGT1？HEP小鼠）。令人惊讶的是，即使完全没有肝UGT1基因座和所有UGT1A蛋白，UGT1DHEP小鼠也对CPT-11治疗和随之而来的肠道毒性具有很大的抵抗力。因此，我们假设UGT1A蛋白的肝外表达有助于SN-38的排毒，在胃肠道缺失UGT1基因座（UGT1？gi小鼠）后，可以进一步证实小鼠。重要的是，我们推测，可以利用对小鼠中UGT1基因座的GI段定向控制，以直接检查该组织对SN-38引起的肠损伤的贡献。为了检查小鼠中UGT1基因座对CPT-11的组织特异性表达的贡献，我们将进行以下实验。特定的目标1将被指示以确定cpt1延迟腹泻中UGT1基因座特异性缺失的影响。在此目的下概述的研究将探索CPT-11诱导的肠道毒性的差异。特定的目标2将检查诱导选择性肠道UGT1A1表达的影响及其对保护肠道组织免受SN-38浓度增加而产生的毒性损伤的增强作用。随着我们实验室最近开发的新型动物模型，这些研究将确定肝和肠道葡萄糖醛酸化对CPT-11诱导的肠道毒性的病因的作用。可以利用这些模型来确定可以改善与CPT-11治疗相关的治疗指数和功效的治疗剂。