UGT1A新等位基因功能的研究及UGT1A基因多态性与伊立替康疗效和毒性的关系

Irinotecan is an anti-cancer (cytotoxic) chemotherapy drug， its toxicity mainly display diarrhea and low neutrophilic granulocyte. UGT1A gene polymorphism was seemed to closely related with the efficacy and toxicity of irinotecan, but the prediction model of Chinese patients for irinotecan efficacy and toxicity is deficiency at present.In our previously alanlysis about UGT1A gene polymorphism as well as irinotecan efficacy and toxicity, multilocus conjoint analysis had a advantage in predicting irinotecan metabolic phenotype compared with the single SNP analysis. And the larger sample size and the more comprehensive site information was used, the more accurate and effective prediction model we would establish. Furthermore, We detected two new missense mutations H203L and L255Q on UGT1A1exon1 and their function will be identified next.The project will increase 150-200 cases and comprehensively sequencing their UGT1A1、UGT1A7 and UGT1A9 using resequence method, including exons and 5 ' UTR ( -1000bp ), and then will clarify the relationship between UGT1A gene polymorphism and irinotecan efficacy and toxicity through correlation analysis method. Moreover, software prediction, cloning, expression, purification and enzyme activity determination will be used to detect the influence of new alleles on protein function. The purpose of the research is to seek for the prediction model of irinotecan efficacy and toxicity aimed to Chinese patients, Identify new UGT1A functional alleles in Chinese patients, and promote the process of Chinese patients individualized medication.

伊立替康属于细胞毒类抗癌药物，其毒性主要表现在腹泻及嗜中性粒细胞减少。UGT1A基因多态性被认为与伊立替康的疗效和毒性相关。目前尚缺乏中国患者伊立替康疗效和毒性的预测模型。本课题组前期对UGTIA基因多态性的研究中，在UGT1A1 exon1上检测到了两个新的错义突变H203L和L255Q，经软件预测可能造成蛋白质结构和功能损害；基因多态性与伊立替康疗效和毒性的关联分析结果表明，与单个SNP相比，多位点联合分析能够更好的预测伊立替康代谢表型。本项目在前期研究的基础上，通过软件预测，克隆、表达、纯化及酶活性测定的办法来鉴定新等位基因对蛋白功能的影响；拟增加入组病例150-200例，采用重测序的方法对UGT1A1、7和9的exon区及5’UTR（-1000bp）进行测序，采用关联分析研究UGT1A基因多态性与伊立替康疗效与毒性的关系，建立针对中国患者伊立替康疗效及毒性的预测模型。

伊立替康属于细胞毒类抗癌药物，其毒性导致的重度腹泻及嗜中性粒细胞减少，严重的影响了伊立替康的使用。在本研究中，共入组70例经伊立替康治疗的转移性胃肠道癌患者。采用重测序的方法对UGT1A1、7和9的exon1区及5’UTR（-1000bp）进行测序，采用关联分析研究UGT1A基因多态性与伊立替康疗效与毒性的关系，建立针对中国患者伊立替康疗效及毒性的预测模型。本研究共检测到23个不同的遗传变异，包括2个新的错义突变。本研究的结果显示，UGT1A1*6，UGT1A7*3与伊立替康引发的严重中性粒细胞减少相关，而UGT1A9 *1B与伊立替康引起的严重腹泻相关。我们在UGT1A1 exon1上检测到了两个新的错义突变H203L和L255Q，经软件预测这两个突变可能造成蛋白质结构和功能损害。我们通过通过软件预测，克隆、表达、纯化及酶活性测定的办法来鉴定了新等位基因对蛋白功能的影响。本项目鉴定了中国患者中新的影响UGT1A 功能的等位基因的功能，建立了针对中国患者伊立替康疗效及毒性的预测模型，为提高不同群体和个体药物治疗有效性及安全性，最终实现一人一药一量的个体化用药目标提供帮助。