Targeting Leukemia causing oncogene E2a-Pbx1 with synthetic molecules

描述(申请人提供)：生物体中的所有细胞，除了少数例外，都具有相同的基因组，但它们专门产生具有不同形态和功能的组织。这种多样性是由于在发育和细胞分化过程中以程序化方式表达的几组基因的差异造成的。最近对人类基因组的解码，加上全基因组的表达谱，正在澄清特定基因表达模式和细胞命运之间的关系。基因表达模式受一系列转录调控因子的控制。在许多类型的癌症中，导致基因表达异常模式的往往是转录调节器失灵，这是疾病的核心。在这种背景下，确定致癌转录调控因子的调控靶点并开发能够控制其表达的合成分子至关重要。理想情况下，这样的合成分子或人工转录因子(ATF)将被设计成对调控网络中的目标基因进行正向或负向调控。这些分子将作为功能基因组学的强大工具，以及解开特定基因的关键转录事件，这些基因决定了细胞的命运。从长远来看，ATF作为化疗药物具有巨大的潜力。这项建议的一个主要目标是确定两个致癌转录因子E2A-Pbx1和HoxA9的DNA调控位点。在所有确诊的儿童前B细胞白血病(B-ALL)中，有25%与E2A-Pbx1有关，而HoxA9的错误调节与急性髓系白血病(AML)的病因有关。识别这两种蛋白质的全基因组DNA调控位点将成为理解控制这些癌症发生的基因调控网络的基础。目前提案的第二个主要目标是开发合成分子来靶向并使人类癌基因E2a-Pbx1失活。这一努力建立在我们针对果蝇同源转录因子的成功以及通过合理设计的人工转录因子上调真核基因表达的基础上。拟议的研究将为开发以其他致癌转录因子的转录和致癌特性为靶点和调控的ATF提供框架。因此，我们将开发一种通用的方法来构建复杂的ATF，这些ATF与内源性转录因子协同作用，以调节基因对细胞信号的反应。我们的工作将共同产生强大的工具，这些工具可以用来研究转录调控的棘手机制特征，剖析全基因组转录网络，作为触发所需转录级联的向导，并控制细胞和有机体的命运。公共卫生相关性：这笔赠款的重点是通过利用基因组和化学策略靶向致癌蛋白E2a-Pbx1来了解和控制控制白血病发病的基因网络。我们的小分子抑制剂的模块化设计原则允许巨大的广度，并广泛适用于与许多不同癌症有关的各种转录调节因子。此外，我们发明的基因组定位和表达研究以及同源位点识别平台在阐明基因网络的性质方面具有直接作用，这些基因网络由于广泛的转录调控因子的错误调控而导致特定形式的癌症。

DESCRIPTION (provided by applicant): All cells in an organism, with a few exceptions, bear the same genome, yet they specialize to give rise to tissues with diverse morphology and function. This diversity arises due to the differences in sets of genes that are expressed in a programmed manner during development and cellular differentiation. The recent decoding of the human genome, coupled with genome-wide expression profiling, is clarifying the relationship between specific gene expression patterns and cell fate. Gene expression patterns are controlled by a host of transcription regulatory factors. In many types of cancers it is often malfunctioning transcriptional regulators that produce aberrant patterns of gene expression that are at the heart of the ailment. In this context, it is critical to identify regulatory targets of oncogenic transcriptional regulators and develop synthetic molecules that can control their expression. Ideally, such synthetic molecules or artificial transcription factors (ATFs) would be engineered to positively or negatively regulate targeted genes within regulatory networks. Such molecules would serve as powerful tools for functional genomics as well as for unraveling key transcriptional events at specific genes that govern cell fate. In the long term, ATFs have significant potential as chemotherapeutic agents. A major goal of this proposal is to define the DNA regulatory sites of two oncogenic transcription factors, E2a- Pbx1 and HoxA9. E2a-Pbx1 is implicated in the onset of 25% of all diagnosed pediatric pre B-cell leukemias (B-ALL) and the misregulation of HoxA9 is linked to the etiology of Acute Myeloid Leukemia (AML). The identification of genome-wide DNA regulatory sites of the two proteins will serve as the basis for understanding the gene regulatory networks that govern the onset of these cancers. The second major goal of the current proposal is to develop synthetic molecules to target and inactivate the human oncogene E2a-Pbx1. This effort builds on our success in targeting homologous transcription factors from Drosophila and the up-regulation of eukaryotic gene expression with rationally designed artificial transcription factors. The proposed studies will provide the framework to develop ATFs that target and regulate the transcriptional and oncogenic properties of other oncogenic transcription factors. We will thus develop a general approach to building sophisticated ATFs that act in concert with endogenous transcription factors to regulate genes in response to cellular signals. Together, our work will generate powerful tools that can be used to study intractable mechanistic features of transcriptional regulation, dissect genome-wide transcriptional networks, serve as guides to trigger desired transcriptional cascades and control the fate of cells and organisms. PUBLIC HEALTH RELEVANCE: This grant is focused on understanding and controlling the gene networks that govern the onset of leukemia by utilizing genomic and chemical strategies to target the oncogenic protein E2a-Pbx1. The modular design principle of our small molecule inhibitors permits enormous breadth and are broadly applicable to a variety of transcriptional regulators that have been implicated in many different cancers. In addition, the genome location and expression studies as well as the cognate site identification platform that we invented have direct utility in elucidating the nature of gene networks that cause specific forms of cancer due to misregulation of a broad swath of transcription regulators.