The role of c-Maf in Stem cells in Leukemia

描述(申请人提供)：转录因子c-Maf在发生急性髓系白血病(AML)的PU1基因敲除小鼠的造血干细胞中上调。在另一种血液系统恶性肿瘤多发性骨髓瘤中，c-maf起癌基因的作用，有助于恶性细胞的聚集。在这里，我们假设c-Maf是正常干细胞的重要调节因子，也是转录主调节因子PU1被击倒诱导的AML中的关键致癌靶点。为了验证这一假设，我们将探索c-Maf在正常和恶性造血干细胞(HSC)和祖细胞中功能丧失和功能获得的后果，以及c-Maf在白血病干细胞的发病和维持中的作用机制。所采用的策略将包括生化实验和功能实验。生化分析，如凝胶迁移分析、染色质免疫沉淀、启动子-报告基因分析和靶向突变，将被用来研究PU1基因敲除与c-Maf上调的关系，并确认c-Maf是否是PU1的直接转录靶点。同时，体外和体内的功能分析将有助于检验c-Maf在正常干细胞和白血病干细胞发育中的重要性。了解c-Maf在AML中的作用可以为直接针对白血病干细胞群中的c-Maf的新的治疗方法提供基础。复发在AML患者中非常常见，据信是这些白血病启动细胞存活的结果；因此，通过专门针对这群恶性细胞，我们相信这种方法可以导致疾病的持久治愈和患者预后的整体改善。

DESCRIPTION (provided by applicant): The transcription factor c-Maf is upregulated in hematopoietic stem cells of PU.1 knockdown mice which develop acute myeloid leukemia (AML). In another hematologic malignancy, multiple myeloma, c-Maf functions as an oncogene, contributing to the accumulation of malignant cells. Here we hypothesize that c-Maf is an important regulator of normal stem cells and a critical oncogenic target in AML induced by knockdown of the transcriptional master regulator PU.1. To test this hypothesis we will explore the consequences of c-Maf loss- of-function and gain-of-function in normal and malignant hematopoietic stem (HSC) and progenitor cells, as well as the mechanism through which c-Maf contributes to the pathogenesis and maintenance of leukemia stem cells. Strategies employed will include both biochemical and functional experiments. Biochemical assays such as Electrophoretic Mobility Shift Assay, Chromatin Immunoprecipitation, promoter-reporter assays and targeted mutagenesis, will be used to address the relationship between PU.1 knockdown and the upregulation of c-Maf, and to confirm whether c-Maf is a direct transcriptional target of PU.1. Meanwhile, in vitro and in vivo functional assays will help examine the importance of c-Maf in normal stem cell and leukemic stem cell development. Understanding the role c-Maf plays in AML can provide the basis for novel therapeutic approaches that aim at directly targeting c-Maf in the leukemia stem cell population. Relapses, which are very frequent in AML patients, are believed to occur as a consequence of the survival of these leukemia initiating cells; hence, by specifically targeting this population of malignant cells, we believe that this approach can lead to lasting cures of the disease and overall improvement in patient outcome.