CML细胞鞘氨醇激酶去SUMO化修饰及在发病中的作用研究

鞘氨醇激酶（SPK）是调节细胞增殖和迁移的重要信号分子并在CML干祖细胞中高表达。我们研究结果证明SPK存在翻译后SUMO化修饰，但SPK 在CML细胞中SUMO化修饰的调控机制以及与CML发病的关系并不清楚。 SENP1是催化去SUMO 化的特异性蛋白酶。本课题将利用基因转移、RNA干涉、造血干祖细胞检测以及转基因小鼠等研究手段，阐明CML细胞中SENPl的表达水平及对SPK 去SUMO化的作用与机制。构建系列SPK1 SUMO位点缺失的突变体，并检测不同突变体对CML细胞增殖、凋亡以及药物敏感性等生物学特性的影响；构建SPK1突变体敲入的转基因小鼠模型，结合逆转录病毒介导的brc-abl 造血干细胞基因转移模型，阐明SPK去SUMO化修饰在CML 发病中的作用。利用化学抑制剂联合抑制SENP1 和SPK1对CML小鼠 的治疗作用。本课题将阐释CML发病及耐药新机制并为其治疗提供靶点。

Sphingosine kinase (SPK) which plays important roles in regulation of cell proliferation and migration is highly expressed by CML stem/progenitor cells. Our preliminary data show that sumoylation is a novel epigenic regulation manner of SPK. However,the mechanisms of SPK sumoylation and its roles in CML pathogenesis remain unclear.The sentrin/SUMO-specific 1(SENP1)functions as a protease that catalyzes SUMO maturation and protein desumoylation. The specific aims of this projects are to elucidate the roles of SPK desumoylaton by SENP1 in CML progress using gene transfer, RNA silence, hematopoietic stem/progenitor cell assay, and transgenic mouse models. The expression level of SENP1 and SPK by sorted CML hematopoietic stem cells and progenitor cells will be detected. Serial mutants of SPK without sumoylation sites will be constructed and transfered into CML cells for their functional assay. The effects of SPK mutants on proliferation, migration, apoptosis of CML cells will be detected. We will also establish the SPK mutant knock in mouse for evaluating the effect of SPK desumoylation on proliferation, differentiation and transformation of hematopoietic stem cells in vivo.The roles of SPK in transformation of hematopoietic stem cells transduced with bcr-abl will be investigated in a transgenic mouse model. The therapeutic effects of dual inhibition of SENP1 and SPK will be evaluated in mouse CML models. Our studies will clarify the roles of SPK desumoylation in bcr-abl transform hematopoietic stem cells and provide novel therapeutic targets for CML therapy.