Role of Transcription Factor ADP-ribosylation in Breast Cancer Biology

项目摘要/摘要 癌症的分子异质性是治疗和药物发现工作的主要障碍。 以前的研究已经通过描述特定癌症的不同分子亚型来应对这一挑战 (例如，乳腺癌)，基于特定细胞类型的基因表达模式。去审问分子 在癌症亚型的基础上，克劳斯实验室开发了一种强大的、多方面的计算 集成来自各种基因组分析的数据以定义增强剂的总功能评分的管道 每个子类型的元素(TFSEE)。这种方法的一个结果是识别癌症亚型- 富含转录因子(TF)促进亚型特异性增强子的形成并驱动下游 转录结果。在乳腺癌中，几个经TFSEE鉴定的亚型特异性TF是独一无二的 同源乳腺癌亚型生长所需，但不影响其增殖或生存能力 其他子类型。最近的研究也表明，ADP-核糖化(ADPR)，一种翻译后的 蛋白质的修饰在不同的乳腺癌亚型中有很大的不同。ADPR化是 由多(ADP-核糖)聚合酶(PARP)家族介导，包括核酶PARP-1 这是FDA批准的PARP抑制剂药物的靶点。PALP因在DNA修复中的作用而广为人知， 但最近的研究表明，BRCA1/2在转录调控中也发挥着重要的作用。在……里面 初步分析，我们已经确定了一组与癌症相关的转录因子，它们在乳腺癌中是ADPR化的。 这些研究的长期目标是更好地理解分子和 ADPR化调控乳腺癌亚型特异性转录因子的生化机制 以及不同乳腺癌亚型对PARP抑制剂的反应。我们的假设是ADPR化 亚型特异性转录因子决定其功能，并可能影响乳腺癌细胞对PARP的反应 抑制剂。我们已经提出了一个项目，它将使用一套完整的生化、分子、细胞和 以小鼠为基础的基因组和蛋白质组分析，以测试我们的总体和特定的机制假说。 具体地说，我们将：(1)确定乳腺癌中ADPR化的转录因子(目标1)，(2)确定如何 转移因子的ADPR化影响其分子和生化功能(目标2)，以及(3)决定 转铁蛋白ADPR化对乳腺癌细胞对临床使用的PARP抑制剂的反应(目标3)。这些研究 将利用PI实验室在PAPS、ADPR化、增强子功能和基因方面的专业知识 对癌症的监管。虽然我们最初关注的是乳腺癌，但我们的结果应该广泛适用于 多种癌症类型。我们使用‘组学’和功能分析的综合方法将提供新的见解 TFADP-核糖化在乳腺癌中的调节，这将成为探索PARP的模型 癌细胞的功能和腺苷二磷酸核糖化。使用基于鼠标的模型和患者样本将允许 我们来探索我们的机制结果的临床相关性。我们预计我们的研究将提出新的建议 PARP抑制剂在DNA修复途径之外的癌症治疗潜力的途径。

Project Summary/Abstract The molecular heterogeneity of cancers poses a major hurdle for treatment and drug discovery efforts. Previous studies have addressed this challenge by characterizing distinct molecular subtypes of specific cancers (e.g., breast cancers), based on cell type-specific patterns of gene expression. To interrogate the molecular underpinnings of cancer subtypes, the Kraus Lab has developed a robust and multi-faceted computational pipeline that integrates data from various genomic assays to define a Total Functional Score of Enhancer Elements (TFSEE) for each subtype. One outcome of this method is the identification of cancer subtype- enriched transcription factors (TFs) that promote subtype-specific enhancer formation and drive downstream transcriptional outcomes. In breast cancers, several TFSEE-identified subtype-specific TFs are uniquely required for the growth of the cognate breast cancer subtype, but do not affect the proliferation or viability of other subtypes. Recent studies have also shown that ADP-ribosylation (ADPRylation), a post-translational modification of proteins, varies dramatically across the different subtypes of breast cancers. ADPRylation is mediated by the Poly(ADP-ribose) polymerase (PARP) family of enzymes, including PARP-1, a nuclear enzyme which is the target of FDA-approved PARP inhibitor drugs. PARPs are well known for the roles in DNA repair, but recent studies suggest an important BRCA1/2-independent role in transcriptional regulation as well. In preliminary analyses, we have identified a cohort of cancer-related TFs that are ADPRylated in breast cancers. The long-term objective of these studies is to achieve a better understanding of the molecular and biochemical mechanisms underlying the regulation of breast cancer subtype-specific TFs by ADPRylation, as well as the responses of distinct breast cancer subtypes to PARP inhibitors. Our hypothesis is that ADPRylation of subtype-specific TFs dictates their function and may influence the response of breast cancer cells to PARP inhibitors. We have proposed a project that will use an integrated set of biochemical, molecular, cell-based, mouse-based, genomic, and proteomic assays to test our overarching and specific mechanistic hypotheses. Specifically, we will: (1) Identify TFs that are ADPRylated in breast cancers (Aim 1), (2) Determine how ADPRylation of TFs affects their molecular and biochemical functions (Aim 2), and (3) Determine the effects of TF ADPRylation on the responses of breast cancer cells to clinically used PARP inhibitors (Aim 3). These studies will take advantage of the expertise of the PI’s lab in PARPs, ADPRylation, enhancer function, and gene regulation in cancer. Although focused initially on breast cancers, our results should be broadly applicable across a variety of cancer types. Our integrative approach using ‘omics’ and functional assays will provide new insights into the regulation of TF ADP-ribosylation in breast cancers that will serve as a model for how to explore PARP function and ADP-ribosylation in cancer cells. The use of mouse-based models and patient samples will allow us to explore the clinical relevance of our mechanistic results. We anticipate that our studies will suggest new avenues for the therapeutic potential of PARP inhibitors in cancers beyond DNA repair pathways.