GLI-UGT1A通路基因多态性与AML患者阿糖胞苷化疗敏感性及机制研究

Acute myeloid leukemia (AML) is an aggressive and heterogeneous hematological malignancy with low 5 year survival rate. Ara-C remains the first-line chemotherapy drug for AML for many years. However, drug resistance is a serious problem during Ara-c based chemotherapy, which becomes the major cause for disease relapse and bad prognosis for AML. UGT1A is a newly identified enzyme responsible for the inactivation of Ara-c, and the expression of UGT1A is regulated by the transcription factor glioma associated protein 1 (GLI1). Our previous study showed that genetic polymorphisms in both GLI1 and UGT1A1 were associated chemosensitivity in AML patients during induction therapy with Ara-c based therapy. In addition, the polymorphisms could also predict AML prognosis in our patients. Based on these previous findings, the program is aimed to validate the association of GLI1 and UGT1A1 polymorphisms with both chemosensitivity and prognosis of AML patients in larger sample size. And also, by using technologies including reporter gene assay, co-immunoprecipitation (Co-IP), we aimed to make clear whether the GLI1 polymorphisms act through affecting the expression of the potential target CYP450 as well as interactions between CYP450 and UGT1A1, the latter is assumed to regulate UGT1A1 stability and degradation. The program is aimed to make clear role of genetic polymorphisms in the GLI1-UGT1A1 pathway in Ara-c response and disease prognosis in AML patients and the related molecular mechanisms, and provide new evidence for individualized therapy for AML.

急性髓系白血病（AML）是一种恶性程度高的血液系统肿瘤，其5年生存率低。阿糖胞苷（Ara-C）是AML一线化疗药物，但耐药率高，是AML复发和预后差的主要原因。UGT1A是新发现的Ara-C代谢灭活酶，并受胶质瘤相关蛋白1（GLI）的调节。本课题在前期发现GLI1和UGT1A1遗传变异与AML患者以Ara-C为基础诱导化疗后化疗敏感性和总生存期相关联的基础上，拟扩大临床样本量证实GLI1和UGT1A1多态性对AML化疗敏感性及预后的影响，并应用报告基因实验、Co-IP等方法查明GLI1多态性是否通过影响其潜在的靶标CYP450的表达和CYP450-UGT1A1相互作用，从而影响UGT1A的降解和AML患者的化疗敏感性。该研究旨在查明GLI-UGT1A通路基因遗传变异在AML患者Ara-C化疗敏感性和预后个体差异中的作用及分子机制，为AML患者的个体化治疗提供理论依据和新的药物基因组标志物。

急性髓系白血病（AML）是一种恶性程度高的血液系统肿瘤，其5年生存率低。阿糖胞苷（Ara-C）是AML一线化疗药物，但耐药率高，是AML复发和预后差的主要原因。UGT1A是新发现的Ara-C代谢灭活酶，并受胶质瘤相关蛋白1（GLI）的调节。本项目共收集AML患者外周血和/或骨髓样本1338例，并收集患者的临床信息，进行体细胞突变检测，完成每3个月一次的定期随访。利用千人基因组数据库筛选出3个错义突变SNP位点（rs2228224/G933D、rs2229300/G1012V、rs2228226/E1100Q）与AML预后相关。分析发现携带rs2229300 T等位基因的患者，总生存期和无病生存期存在显著的差异。构建携带rs2229300位点野生型和突变型报告基因质粒进行双荧光素酶报告基因实验，发现rs2229300 T变异引起GLI1蛋白的转录活性增强。GO富集到224个通路中，包括白细胞迁移和趋化、细胞因子的分泌、造血系统分化等。相对于rs2229300 GG基因型患者，rs2229300 TG基因型患者单个核细胞（PBMC）中GLI1靶基因CCND1、CD44、PROM1的mRNA表达发生改变。携带UGT1A1*28、*6等位基因可增加AML患者诱导化疗反应性，可延长AML患者总生存期，但PBMC中UGT1A1 mRNA的表达丰度低，提示UGT1A1基因多态性可能主要不是在白血病细胞中影响阿糖胞苷的代谢，其可能主要在肝脏影响阿糖胞苷的代谢从而影响其血药浓度。本项目通过探明GLI-UGT1A通路基因遗传变异在AML患者Ara-C化疗敏感性和预后个体差异中的作用及分子机制，为AML患者的个体化治疗提供理论依据和新的药物基因组标志物。