急性髓系白血病细胞中IGFBP2抑制PTEN转录活性的分子机制研究

PTEN是具有磷酸酶活性的抑癌基因，急性髓系白血病（AML）鼠模型中敲除PTEN促进白血病起始细胞的生成。SP1通过募集HDAC1使组蛋白去乙酰化而抑制PTEN转录。前期实验表明胞内IGFBP2通过抑制PTEN表达而激活PI3K/AKT信号，促进AML进展；IGFBP2与SP1相互结合并抑制PTEN启动子活性。基于此，我们推测核IGFBP2通过促进SP1募集HDAC1抑制PTEN转录,阻止AML细胞凋亡。我们拟收集临床标本分析IGFBP2、SP1、HDAC1和PTEN的表达相关性；借助过表达/RNAi、荧光素酶报告分析、定点突变、共聚焦、CHIP-seq、EMSA、CHIP-qPCR、CO-IP等实验验证IGFBP2通过促进SP1募集HDAC1，形成SP1/IGFBP2/HDAC1复合体抑制PTEN转录。该课题揭示IGFBP2抑制PTEN转录活性的分子机制，将为AML靶向治疗提供理论依据。

PTEN is a tumor suppressor gene with protein and lipid phosphatase activity. The ablation of PTEN has been demonstrated to promote generation of leukemia- initiating cells in acute myeloid leukemia (AML) mouse model. SP1 inhibits the promoter activity of PTEN by recruiting the histone deacetylase HDAC1. Our previous experiments showed that nuclear IGFBP2 supported AML development by inhibiting PTEN transcription and activating PI3K/AKT signal pathway, Nuclear IGFBP2 bound to SP1 and inhibited the promoter activity of PTEN. Based on these data, we proposed the hypothesis that nuclear IGFBP2 inhibits the expression of PTEN at the transcriptional level and suppresses the apoptosis of AML cells by promoting the recruitment of HDAC1 to SP1. In order to verify this hypothesis, we propose to collect clinical specimens to analyze the expression correlation of IGFBP2, SP1, HDAC1 and PTEN. In this study, it will be verified that IGFBP2 inhibits PTEN transcription by promoting the recruitment of HDAC1 to SP1 and enhancing the formation of SP1/IGFBP2/HDAC1 complex by using overexpression /RNA interference, luciferase reporter analysis, site-directed mutation, confocal, CHIP-seq, EMSA, CHIP-qPCR, CO-IP and other experiments. This study will provide important insight into the mechanism and targeted treatment of AML.