The role of c-Maf in Stem cells in Leukemia

描述（由申请人提供）：转录因子c-Maf在发生急性髓性白血病（AML）的PU.1敲除小鼠的造血干细胞中上调。在另一种血液恶性肿瘤多发性骨髓瘤中，c-Maf作为癌基因发挥作用，促进恶性细胞的积聚。在这里，我们假设c-Maf是正常干细胞的重要调节因子，并且是通过敲低转录主调节因子PU.1诱导的AML中的关键致癌靶点。为了验证这一假设，我们将探讨c-Maf功能丧失和功能获得在正常和恶性造血干细胞（HSC）和祖细胞的后果，以及通过c-Maf有助于白血病干细胞的发病机制和维护。所采用的策略将包括生物化学和功能实验。将使用诸如电泳迁移率变动测定、染色质免疫沉淀、启动子-报告基因测定和靶向诱变的生化测定来解决PU.1敲低与c-Maf上调之间的关系，并确认c-Maf是否是PU.1的直接转录靶标。同时，在体外和体内的功能测定将有助于检查的正常干细胞和白血病干细胞发育的c-Maf的重要性。了解c-Maf在AML中的作用可以为旨在直接靶向白血病干细胞群体中的c-Maf的新型治疗方法提供基础。AML患者中非常常见的复发被认为是这些白血病起始细胞存活的结果;因此，通过特异性靶向这一恶性细胞群体，我们相信这种方法可以导致疾病的持久治愈和患者结局的总体改善。

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.