miR-150在急性髓细胞白血病中的表达和功能研究

Expression of miRNAs, a new class of small noncoding RNAs，has been demonstrated to be altered in acute myeloid leukemia(AML) and associated with specific cytogenetic subsets and prognostic relevance. Changes in the expression of several miRNAs altered in AML have been shown to have functional relevance in leukemogenesis. We have found that miR-150,an important regulator in hematopoiesis and immune system, is down-regulated in AML. Restoration of miR-150 in AML cell lines dramatically inhibits cell growth，and initiates caspase3 activtion,leading to cell death through unknown mechanisms. Therefore, we presumed that miR-150 might play important roles in pathogenesis and disease progression in AML. In this study, we will analyze the probability correlation of miR-150 expression with specific cytogenetic subsets and prognostic significance of AML. Then, the hypothesis that exogenous expression of miR-150 can inhibit leukemia cell growth and reduce tumorigenicity will be verified in vitro as well as in a xenograft leukemia animal model. Microarray and luciferase assays will be used to predict and validate its targets. Finally, we carry out GO categories to functional annotation analysis of these predicted targets and their involvement in biological processes as well as signaling pathways. Together, our research will help to elucidate the possible roles and mechanisms for miR-150 functions in AML and provide a rationale for the use of miR-150 as a novel strategy for AML treatment.

miRNAs是一类小分子的非编码RNAs，其表达变化与急性髓细胞白血病（AML）特定的遗传学改变和预后相关，在AML发病机制中起重要调控作用。miR-150是造血和免疫系统的一个关键调节因子，我们前期研究发现它在AML显著低表达，外源性miR-150明显抑制白血病细胞的活性,并激活caspase3启动细胞凋亡,但机制尚不清楚。我们推测miR-150表达下调或缺失是AML遗传学改变的一个关键事件，通过调控相关基因和信号参与AML的发生发展。本项目拟通过检测AML患者miR-150表达水平并分析与特定遗传学改变和预后的关系，同时在细胞和动物模型上验证miR-150对白血病细胞生长和致瘤能力的抑制作用，应用差异基因表达分析、荧光素酶报告系统等手段预测和确证miR-150的关键靶基因及相关信号调节通路，阐明miR-150在AML中的作用和分子机制，为以miR-150为靶点的生物学治疗提供理论依据。

miRNAs 是一类小分子的非编码 RNAs，参与基因的表达调控和几乎所有的生物学过程。miR-150 是造血和免疫系统的一个关键调节因子，其异常表达参与各种血液系统肿瘤的发生，是一个潜在的治疗靶点。我们发现白血病患者中miR-150表达普遍降低，而经过治疗缓解后其表达恢复到正常水平。外源性miR-150可显著抑制白血病细胞的增殖和诱导细胞凋亡，同时可抑制白血病细胞在小鼠移植模型的成瘤作用。这里，我们首次应用基因微阵列结合生物信息学的方法鉴定出42个miR-150相关靶基因，并采用实时定量PCR和荧光素酶表达系统进一步验证这些靶基因。为了进一步阐明miR-150及其靶基因的分子功能和生物学作用，我们采用GO数据库和生物反应路径分别对这些靶基因进行基因功能分类和信号转导途径分析，结果显示miR-150主要参与细胞小分子代谢过程 (POM121,PISD,STX1A,AMD1,PRKCA,NDST1,ACSL4), 基因的转录调控 (FOXO4,IKZF1,TET3,NFIC,RUNX1, EIF4B,CTIF), RNA代谢过程(EIF4B,PRKCA,PDCD4), 肿瘤的蛋白聚糖代谢 (PDCD4,PRKCA,FZD4,EIF4B)以及mTOR (PRKCA,EIF4B) 和Wnt (FZD4,PRKCA)信号通路。最后干扰其中的EIF4B, FOXO4,PRKCA和TET3基因的表达，也能抑制白血病细胞的生长，这些结果充满说明miR-150通过多种生物效应发挥抗白血病作用。我们的研究结果阐明 miR-150 在白血病中的作用和分子机制，为以 miR-150 为靶点的生物学治疗提供理论依据。