基于eIF3a基因多态、microRNA及其启动子DNA甲基化的铂类耐药分子机制研究

肺癌化疗主要以铂类药物为主，但个体反应差异性大，耐药现象十分严重。近年来表观遗传学在药物反应差异中的作用逐渐受到极大关注，主要包括DNA甲基化修饰以及microRNA调控。我们前期工作发现，eIF3a基因及多态可以通过调控DNA修复途径蛋白表达来调节肺癌铂类药物化疗敏感性。在此基础上，本课题首先使用激光共聚焦和Gel shift等方法进一步阐明我们发现的eIF3a C1458T和G2554A新突变对eIF3a功能的影响，然后使用荧光素酶报告基因和甲基化PCR方法筛选影响eIF3a功能的microRNA和启动子甲基化位点，阐明其影响eIF3a功能的分子机制；最后查明调控eIF3a基因的多态、microRNA和DNA甲基化位点与肺癌铂类药物化疗敏感性的关系。本课题旨在从表观遗传学的角度为肺癌铂类药物耐药的发生提供新的解释机制，对以基因为导向的铂类药物化疗提供理论依据和实验依据。

Lung cancer is a severe harmful tumor with common occurrence for human life and health all over the world. The chemotherapy of patients with lung cancer is mainly treated with platinum-based drugs, but a great deal of the individual diffrences and resistances of drugs response exist commonly in the treatment course of lung cancer patients. Recently, the role of epigenetics involved in the DNA methylation modification and miRNA modulation in drug response differences is gradually concerned and emphasized by the people. In the our previous studies, we found that the genetic polymorphisms of eukaryotic translation initiation factors-3 (eIF3a) can modulate the chemotherpy sensitivity in lung cancer patients treated with platinum-based medicine by regulating the protein expression of DNA repair pathway. On the basis of these results, this project is going to clarify the effects of two novel eIF3a mutants (eIF3a C1458T and G2554A, found by our groups) on eIF3a biological funtion and molecular mechanism, screen the microRNAs and promoter methylation sites related to eIF3a function by the use of the Luciferase reporter gene assay and methylation PCR technology as well as elucidate the molecular mechanisms of microRNAs and promoter methylation level regulating the eIF3a function. Finally, we are going to investigate the relationship between the genetic polymorphism of eIF3a, microRNAs, and promoter methylation sites and the efficacy of chemotherapy in large samples of lung cancer patients treated with platinum-based drugs. The aim of this projects will can provide some new mechanism explanations with the resistance occurrence in the treatment of platinum-based drugs in patients with lung cancer from epigenetics analysis and theoretical basis and experimental evidence with formulation of individualized chemotherapy program to gene-guidance platinum-based treatment.