SARI转录抑制机制及在急性髓细胞白血病发病中的作用

Acute Myeloid Leukemia (AML) is a group of heterogeneous disease which seriously affects the survival and prognosis of the patients. It has been reported recently that SARI abnormality involves in tumorigenesis and prognosis. Our group firstly found that expression of SARI in AML patients is low or absent at both protein and mRNA level; transcription inhibitor ACTD and RelA specific inhibitor PDTC could prevent IFN-β-induced SARI expression in AML derived cell lines (RelA was activitied in this process),which hinted that transcription suppression of SARI resulted in its low expression as well as the abnormal pathways in AML.Therefore, it has great significance for the further study that to trace the role of SARI transcription suppression and the mechanisms in AML. This study aims at: ①to confirm the correlations between SARI and the clinical features, efficacy and the prognosis of AML patients to a great clinical level; ②to detect the changes of gene-spectra, regulatory signal pathway in AML patients and IFN-βunblocked inhibition of SARI expression in AML derived cells by the aid of gene microarray and bioinformatics technology, so as to elucidate the mechanism underlying the transcription prohibition of SARI in AML; ③to clarify the etiologic role of SARI in AML as well as the mechanisms by means of the cell line and animal experiments,etc.- so that to lay the foundation for gene diagnosis and therapy of the AML patients and drug targets screening in clinical use in future.

急性髓细胞白血病（AML）是一组异质性疾病，严重影响患者的生存和预后。新研究报道SARI异常参与肿瘤发生及预后。我们率先研究发现AML中存在SARI蛋白及其mRNA低表达；转录抑制剂ACTD及RelA阻滞剂PDTC均可阻断AML细胞系中IFN-β诱导的SARI表达(RelA可被激活)，提示 AML中可能存在SARI转录抑制导致的低表达及信号异常。因此，深入研究SARI及其转录抑制在AML发病中作用及机制有重要意义。本项目拟①在临床更大层面上确证SARI 与AML临床特征、疗效及预后的相关性；②通过转录水平系列实验并结合基因芯片及生物信息技术检测AML患者及IFN-β解除SARI抑制的基因表达谱、调控网络及信号通路变化以明确SARI在AML中转录抑制机制；③通过细胞及动物水平等相关实验阐明SARI在AML发病中的生物学效应和机制。为AML患者的基因诊疗及药物靶点筛选的临床应用奠定基础。

AML是一组异质性疾病，严重影响患者的生存和预后。新研究报道SARI异常参与肿瘤发生及预后。我们率先研究发现AML中存在SARI低表达；转录抑制剂及RelA阻滞剂均可阻断AML细胞中IFN-β诱导的SARI表达(RelA被激活)，提示 AML中可能存在SARI转录抑制导致的低表达及信号异常。因此，深入研究SARI及其转录抑制在AML发病中作用及机制有重要意义。本项目①在临床更大层面上收集标本，通过Real-time PCR及Western blot等技术检测确证了SARI 与AML临床特征、疗效及预后的相关性。②采用生物信息学数据库及软件预测SARI启动子区可能的转录因子结合位点，并检测了临床标本中相关转录因子表达情况及其与SARI表达的相关性。③采用慢病毒转染的过表达及小干扰RNA方法，结合MTT比色法、细胞克隆形成实验、侵袭实验、流式细胞学及qPCR和Western blot等系列细胞学实验技术，分别研究了SARI过表达及下调状态对白血病细胞生物学特性和信号网络的影响及其可能途径。④通过建立SARI过表达小鼠模型，在动物水平初步验证了SARI在AML发病中的生物学效应。结果显示：（1）SARI基因与AML患者的缓解率和总生存率呈正相关，可作为AML诊断、疗效和预后判断的辅助指标。（2）通过CONSITE和JASPAR数据库预测发现SARI启动子区有转录因子MZF1-4、AML1、NF-κB及c-myc的结合位点，通过5种软件检测均未找到SARI启动子区的CpG岛，因CpG岛异常导致SARI下调的可能性较小。（3）SARI上调可能通过抑制Akt/PI3K通路、抑制转录因子MZF-1、NF-κB（RelA）的表达明显抑制AML Kasumi-1、HL-60、NB4细胞的增殖，诱导细胞早期凋亡。（4）在K562细胞中，下调SARI可通过抑制PI3K信号通路及细胞周期信号蛋白引起细胞增殖抑制和周期阻滞，此结果与SARI 过表达结果相反，可能与细胞类型及细胞分化程度有关。（5）SARI基因的过表达在体内条件下能抑制细胞增殖，诱导细胞凋亡，抑制肿瘤细胞生长。该课题深入探讨了SARI在AML细胞中发挥生物学功能可能的作用机制，为AML患者的基因诊疗及可能的药物靶点筛选提供了理论及实验基础。