基于AML鼠模型研究SOX6抑制AML发生发展的分子机制

Acute myeloid leukemia (AML) is a heterogeneous disease with variable clinical outcomes. The pathogenesis is very complex and so far the mechanism of AML remains elusive. Our preliminary results showed that the expression of SOX6 significantly decreased in AML cells and CD34+ AML stem cells, and that overexpression of SOX6 in THP1 cells inhibited cell proliferation, induced cell cycle arrest. It was confirmed that overexpression of SOX6 significantly extended the survival of AML mice with retroviral overexpression system in combination with mouse transplantation model. In order to study the mechanism for inhibition of the development of AML by SOX6, we propose to build an SOX6 conditional knockin mouse model. We will further dissect the phenotypes of sox6 inhibiting the develomment of AML by approaches including bone marrow transplantation, blood immunophenotyic analysis, as well as pathologic analysis. CO-IP and mass spectrometry will be performed to identify the binding protein of SOX6. RNA-seq, CHIP-seq and bioinformatics analysis will be performed to investigate the regulatory pathways of SOX6. Key candidate effectors correlating to SOX6 will be functionally evaluated by gene overexpression/knockdown approaches. This study will provide important insight into the mechanism and targeted treatment of AML.

急性髓系白血病（AML）异质性强，发病机制非常复杂，迄今未完全明了。前期研究表明SOX6低表达于AML细胞及CD34+AML干细胞中；SOX6过表达抑制了AML细胞系THP1增殖，阻滞了细胞周期；此外，我们借助逆转录病毒系统和小鼠移植模型，证实了SOX6过表达可显著延长AML小鼠的生存期。基于此，我们推测SOX6可能抑制AML发生发展，但其机制尚不清楚。本课题拟构建条件性过表达SOX6的基因敲入小鼠模型，并通过骨髓移植、血液免疫表型分析、骨髓病理学分析等方法进一步明确SOX6抑制AML发生发展的表型。借助CO-IP及质谱技术鉴定SOX6抑制AML的相关核内结合蛋白。结合RNA-seq、CHIP-seq及生物信息学解析SOX6的调控通路，并通过表达调控技术对候选效应分子进行功能验证。该课题将在AML动物模型上揭示SOX6抑制AML发生发展的分子机制，为AML临床靶向治疗提供理论依据。

急性髓系白血病（AML）异质性强，发病机制非常复杂，迄今未完全明了。作为抑癌基因，SOX6通过参与了调控细胞周期及细胞增殖抑制了多种肿瘤的发生发展。多个数据库生物信息学分析发现SOX6的表达量与AML患者的生存期成正相关。我们发现SOX6低表达于AML细胞及CD34+AML干细胞中。体外细胞实验我们在THP1和U937 细胞内过表达SOX6，初步明确SOX6抑制AML细胞增殖。体内实验我们构建条件性过表达SOX6的基因敲入小鼠，并通过转导MLL/AF9融合癌基因及骨髓移植、血液免疫表型分析、骨髓病理学分析等方法进一步明确了SOX6抑制AML的发生发展。 体内外实验均证实SOX6通过阻滞细胞周期于G0/G1期，抑制DNA合成而减弱了AML细胞增殖活力，但不影响AML细胞凋亡。SOX6抑制了AML干细胞的克隆形成能力，上调p21，但下调CDK2、CDK4、CDK6、c-Myc、Cyclin D1、Cyclin E1等细胞周期相关基因的表达。SOX6抑制β-catenin/TCF4复合体的转录活性。我们的研究结果表明在白血病细胞中SOX6通过抑制Wnt/β-catenin信号通路中的β-catenin /TCF复合物的转录活性而下调c-Myc、Cyclin D1等细胞周期相关基因的表达，阻滞AML细胞周期于G0/G1期，从而抑制AML发生发展。该研究为通过靶向 SOX6关键通路治疗 AML 提供理论基础和实验依据。