Delineating ARF negative regulation of PAF1C-dependent oncogenic programs

描绘 ARF 对 PAF1C 依赖性致癌程序的负调控

• 批准号: 10437541
• 负责人: Ivan D'Orso
• 金额: $ 8.2万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-08 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10437541
• 关键词: Abnormal Cell; Acute; Address; Affect; Applications Grants; Back; Binding; Biochemical; Biochemical Genetics; Biological Process; Biology; CDKN2A gene; Cancer Biology; Cancer Patient; Cancer cell line; Cell Death; Cell Line; Cells; Clinic; Clinical; Complex; Data; Development; Diagnostic; Differentiation and Growth; Equilibrium; Exhibits; GDF15 gene; Gene Activation; Gene Expression Regulation; Genes; Genetic Transcription; Goals; Growth; Human; In Vitro; Interruption; Knowledge; Ligands; Lung Adenocarcinoma; Maintenance; Malignant Neoplasms; Mission; Molecular; Oncogenic; Pancreatic Adenocarcinoma; Patients; Phosphorylation; Pre-Clinical Model; Process; RUNX1 gene; Reading Frames; Regulation; Research Proposals; Sampling; Signal Transduction; Specificity; Specimen; System; TP53 gene; Testing; Therapeutic; Tumor Promoters; Tumor Suppression; Tumor Suppressor Proteins; Work; Xenograft procedure; bench to bedside; bone; cell growth; genetic approach; improved; insight; loss of function; lung cancer cell; morphogens; new therapeutic target; novel; pancreatic differentiation 2 protein; prevent; programs; response; sarcoma; small molecule; therapeutic target; transcription factor; tumor; tumorigenesis; uncontrolled cell growth; unpublished works

PROJECT SUMMARY Tumor suppressors (TS) tune the balance of cell growth and death by acting at multiple levels. Deregulation of any of these hierarchies can promote tumorigenesis, impact cancer patient’s survival and response to currently available treatments. Therefore, having a better understanding of these processes and the identification of novel therapeutic targets upon TS loss is a priority in the field of cancer biology. Decades of work have defined how the p14ARF (Alternative Reading Frame) TS operates in a p53-dependent manner to prevent tumorigenesis. However, ARF also operates in a p53-independent manner to potentially “back-up p53”, but the mechanisms remain poorly understood. There is a regained idea in the field to delve into tumor suppressive mechanisms and to leverage the basic biology to therapeutic opportunities. In this context, the major goal of this research proposal is to define how ARF (reactivated upon p53 loss) functions to restrain tumor promoter programs. Our unpublished studies have defined a previously overlooked mechanism of ARF tumor suppression. First, upon p53 loss, reactivated ARF selectively targets the Polymerase Associated Factor 1 complex (PAF1C) at genes encoding the pro-growth GDF and BMP ligands to restrain abnormal cell growth. Second, loss of ARF in primary p53-/- cells de-repress GDF/BMP programs leading to SMAD1/5 phosphorylation and target gene activation (“oncogenic GDF/SMAD axis”), suggesting oncogenic vulnerabilities accrued upon double TS (p53 and ARF) loss emerge as alternative therapeutic targets. However, it remains unknown how ARF inactivates PAF1C in a gene-specific manner and whether the oncogenic GDF/SMAD axis has any diagnostic and therapeutic value. This small grant proposal aims at addressing how ARF inactivates PAF1C in a gene-specific manner to restrain tumor promoter programs and to evaluate the therapeutic value of targeting the oncogenic GDF/SMAD program. Work in this proposal is guided by these previous findings and critical gaps in knowledge to test the central hypothesis that ARF binds Paf1 and the gene-specific factor RUNX1 to block PAF1C assembly in a gene-specific manner thereby restraining tumor promoter programs. To test the underlying hypothesis, we will leverage biochemical and genetic approaches as well as clinically and molecularly annotated preclinical models. Specifically, we will first investigate how ARF binds Paf1 and RUNX1 to block PAF1C assembly in a gene-specific manner (Aim 1), and then probe if tumors bearing double TS (p53 and ARF) loss exhibit reactivation of the oncogenic GDF/SMAD axis and examine its therapeutic and diagnostic potential (Aim 2). Together, elucidating the mechanisms by which ARF negatively regulates PAF1C-dependent tumor promoter transcriptional programs will improve our understanding of an important biological process and offer alternative opportunities to target TS loss in cancers with dual ARF and p53 inactivation (such as sarcoma, pancreas, and lung adenocarcinoma), which is in-line with NCI’s mission to identify novel targets to move the discoveries from the bench to the clinics.

项目概要 肿瘤抑制因子（TS）通过在多个水平发挥作用来调节细胞生长和死亡的平衡。放松管制 这些层次中的任何一个都可以促进肿瘤发生，影响癌症患者的生存和对当前疾病的反应 可用的治疗方法。因此，更好地理解这些过程并识别新颖的 TS 丢失的治疗目标是癌症生物学领域的一个优先事项。数十年的工作已经定义了如何 p14ARF（替代阅读框）TS 以 p53 依赖性方式发挥作用，以预防肿瘤发生。 然而，ARF 也以独立于 p53 的方式运行，以潜在地“备份 p53”，但其机制 仍然知之甚少。该领域重新流行了深入研究肿瘤抑制机制和 利用基础生物学来获得治疗机会。在此背景下，本研究计划的主要目标 的目的是定义 ARF（p53 丢失后重新激活）如何发挥作用来抑制肿瘤启动子程序。我们未发表的 研究已经明确了以前被忽视的 ARF 肿瘤抑制机制。首先，在 p53 丢失后， 重新激活的 ARF 选择性地靶向编码基因的聚合酶相关因子 1 复合物 (PAF1C) 促生长 GDF 和 BMP 配体可抑制异常细胞生长。其次，初级 p53-/- 中 ARF 的丢失 细胞去抑制 GDF/BMP 程序，导致 SMAD1/5 磷酸化和靶基因激活 （“致癌 GDF/SMAD 轴”），表明双 TS（p53 和 ARF）产生致癌脆弱性 损失成为替代治疗目标。然而，目前尚不清楚 ARF 如何在 ARF 中灭活 PAF1C。 基因特异性方式以及致癌 GDF/SMAD 轴是否具有任何诊断和治疗价值。 这项小额赠款提案旨在解决 ARF 如何以基因特异性方式灭活 PAF1C 抑制肿瘤促进程序并评估针对致癌基因的治疗价值 GDF/SMAD 计划。本提案中的工作以这些先前的发现和知识方面的关键差距为指导 检验 ARF 结合 Paf1 和基因特异性因子 RUNX1 以阻断 PAF1C 的中心假设 以基因特异性方式组装，从而抑制肿瘤启动子程序。测试底层 假设，我们将利用生化和遗传学方法以及临床和分子注释 临床前模型。具体来说，我们首先研究ARF如何结合Paf1和RUNX1来阻断PAF1C 以基因特异性方式组装（目标 1），然后探测肿瘤是否具有双 TS（p53 和 ARF）丢失 表现出致癌 GDF/SMAD 轴的重新激活并检查其治疗和诊断潜力（目标 2）。共同阐明 ARF 负向调节 PAF1C 依赖性肿瘤启动子的机制 转录程序将提高我们对重要生物过程的理解并提供替代方案 通过 ARF 和 p53 双重失活来靶向治疗 TS 丢失的机会（例如肉瘤、胰腺癌和 肺腺癌），这符合 NCI 的使命，即确定新的靶点以将这些发现从 到诊所的长凳。