The role of AF10 in normal and leukemic hematopoiesis

描述（由申请人提供）：该项目的总体目标是为血液系统恶性肿瘤的表观遗传失调机制提供新的见解，从而可能导致改进的治疗策略。携带AF10转录因子染色体重排的白血病以染色质1-3的特异性扰动为标志，从而为肿瘤发生中表观遗传失调的研究提供了一个很好的模型。我们假设AF10白血病的表观遗传失调是由于AF10 n端PHD结构域的缺失和致癌AF10融合体中c端八肽基序亮氨酸zipper （m - lz）结构域的保留。我们的初步观察表明，AF10融合癌基因的转化可以通过抑制AF10 OM-LZ结构域的活性来抑制，或者通过恢复致癌AF10融合中的PHD锌指结构域来抑制。这些观察结果对AF10白血病具有很大的治疗前景。在Specific Aim 1中，我们建议使用已建立的白血病和基因敲除小鼠模型来确定导致肿瘤抑制的机制，然后采用高通量方法。这些研究的临床相关性是由AF10参与多种血液恶性肿瘤的复发性染色体易位这一事实所证实的4-8。此外，其他几种癌症也具有AF10白血病的共同特征，特别是PHD结构域9-12或组蛋白甲基转移酶dot1l13的参与，以及对发育至关重要的HOX基因的缺失14,15。因此，拟议的研究可能对HOX基因在癌症中解除管制的共同机制产生有价值的见解。我们的初步结果支持AF10在哺乳动物HOX基因调控中的作用。这一功能的解除似乎是AF10白血病肿瘤发生中的一个关键事件。因此，为了深入了解AF10在正常和白血病造血中的作用，我们建议使用生化和基因靶向方法确定AF10在正常和白血病造血中的作用。具体来说，我们计划表征AF10的转录活性，并在specific Aim 2中建立AF10造血特异性缺失的条件敲除小鼠。先前的研究支持AF10在HOX基因1,2,16,17的调控中发挥作用。建立AF10敲除小鼠将能够评估AF10的功能，包括对HOX基因的潜在调节，HOX基因在正常和恶性造血中起重要作用。由于AF10-DOT1L网络是一个有价值的治疗靶点，鉴定该网络的成分可能为其潜在的药理学抑制提供关键信息。拟议的项目将在一个丰富的学术机构环境中进行，并将由知名科学家组成的指导委员会指导。该提案得到了强有力的培训组成部分的支持，包括表观遗传学和血液病理学的教学和实践指导，负责任的研究行为的培训，以及成功过渡到独立研究者的指导能力的获得。

DESCRIPTION (provided by applicant): The overall goal of this project is to offer novel insights into the mechanisms of epigenetic deregulation in hematological malignancies that may lead to improved therapeutic strategies. Leukemias bearing chromosomal rearrangements of the AF10 transcription factor are marked by specific perturbations of chromatin 1-3, thereby providing an excellent model for the study of epigenetic deregulation in oncogenesis. We hypothesize that epigenetic dysregulation in the AF10 leukemias results from the loss of the N-terminal PHD domains of AF10 and the retention of the C-terminal octapeptide motif-leucine zipper (OM-LZ) domain in oncogenic AF10 fusions. Our preliminary observations show that transformation by AF10 fusion oncogenes can be suppressed by inhibiting the activity of the AF10 OM-LZ domain or alternatively, by restoring the PHD zinc finger domain in oncogenic AF10 fusions. These observations hold great therapeutic promise for the AF10 leukemias. In Specific Aim 1, we propose to identify mechanisms that lead to tumor suppression using established models of leukemia and knockout mice, followed by high throughput approaches. The clinical relevance of these studies is borne out by the fact that AF10 is involved in recurrent chromosomal translocations in a wide variety of hematological malignancies 4-8. Moreover, several other cancers share features common to the AF10 leukemias, notably - involvement of PHD domains 9-12 or the histone methyltransferase DOT1L 13 together with deregulation of the developmentally critical HOX genes 14, 15. The proposed studies may therefore yield valuable insights into common mechanisms of HOX gene deregulation in cancer. Our preliminary results support a role for AF10 in the regulation of mammalian HOX genes. Deregulation of this function seems to be a critical event in oncogenesis of AF10 leukemias. Therefore, to gain insights into the role of AF10 in normal and leukemic hematopoiesis, we propose to identify the role of AF10 in normal and leukemic hematopoiesis using biochemical and gene-targeting approaches. Specifically, we plan to characterize the transcriptional activity of AF10 and establish conditional knockout mice with hematopoietic specific deletions of AF10 in Specific Aim 2. Prior studies support a role for AF10 in the regulation of HOX genes 1, 2, 16, 17. Establishment of AF10 knockout mice will enable assessment of AF10 function including potential regulation of HOX genes that have important roles in normal and malignant hematopoiesis. Since the AF10-DOT1L network is a valuable therapeutic target, identification of components of this network may provide critical information for its potential pharmacologic inhibition. The proposed project will be carried out in a rich academic institutional environment, and will be guided a mentoring committee composed of renowned scientists. The proposal is supported by a strong training component that includes didactic and practical instruction in epigenetics and hematopathology, training in the responsible conduct of research, and acquisition of mentoring abilities for successfully transitioning to an independent investigator.