急性早幼粒细胞白血病中砷剂耐药的分子机制研究

砷剂治疗急性早幼粒细胞白血病疗效显著，但仍有部分病人复发且预后极差，阐明砷剂耐药的机制非常关键。我们前期研究发现，砷剂耐药病人中69%出现PML-RARA基因的PML发生突变，发现4个新的突变位点(Zhu HH, et al.NEJM,2014;370:1864)；另外，我们在PML突变的APL病人中发现砷剂耐药程度有差异。本课题组提出假说：PML突变直接导致砷剂耐药，是耐药的主要机制，不同PML突变类型的耐药程度不同。拟进行（1）构建PML野生型和不同突变类型的细胞系，加入三氧化二砷，观察砷细胞内定位、PML-RARA蛋白降解、Sumoylation化、核体构象, 证实PML发生突变直接导致砷剂耐药，并通过小鼠模型进行验证，探索克服耐药的药物。（2）对不同PML突变类型病例采取个体化干预试验研究，评价疗效。本研究旨在阐明砷剂耐药的分子机制以及可能的治疗方法，具有重要的基础和临床意义。

Arsenic recently becomes first-line treatment of acute promyelocytic leukemia (APL). Unfortunately, some patients developed arsenic-resistance and their outcomes were extremely dismal. To elucidate the mechanism of arsenic-resistance and explore possible treatment strategy is very important. We recently found that 9 patients habored PML mutations in 13 arsenic-resistant APL patients and 4 novel mutions were first reported by us（Zhu HH, et al.NEJM,2014;370:1864). We also found distinct PML-RARA mutations have different degrees of arsenic-resistance in clinical practice.We hypothesized that PML mutations is the cause of arsenic-resistance and distinct PML-RARA mutations have different degrees of arsenic-resistance. To answer these questions, we designed this study. We plan to construct wild-type and mutated PML-RARA plasmid and tranfer to cell lines. By incubating with different concentration of arsenic, we study the arsenic-binding capacity, PML-RARA degradation, Sumoylation levels and protein localization. We also confirm these results in mice model. Moreover, we investigate mutation-directed treatment in arsenic-resistanc APL patients to overcome arsenic-resistance. This study provide important evidence to the mechanism of arsenic-resistance and treatment strategy.