Antagonistic role of ARF and ADAR1 in triple-negative breast cancer

项目摘要 三阴性乳腺癌（TNBC）由于其自身的原因仍然是相当大的临床挑战。 缺乏有效的基因靶点。我们需要独特有效的疗法和准确的生物标志物 可用于预测TNBC患者的反应。我们发现ARF肿瘤抑制因子 在60%的TNBC中与p53突变一起丢失。可能源于ARF的双重丧失 和p53，我们已经观察到I型IFN信号传导在TNBC中升高。我们表明，这种干扰素 生产被ADAR 1酶控制。值得注意的是，我们发现ADAR 1是 一种新的ARF结合伴侣。这项提议的中心前提是，新的ARF-ADAR 1 相互作用提供了对这两种蛋白质在TNBC的病因学中如何起作用的关键见解。的 研究应用集中于这种相互作用在调节I型干扰素中的作用 使TNBC细胞对细胞死亡和免疫识别敏感。总体 本研究的假设是ARF和p53的缺失导致I型IFN的升高 信号传导并使细胞对ADAR 1耗竭敏感。 在目标1中，我们将定义ARF和ADAR 1的功能相互作用。在缺乏功能的情况下， p53、ARF蛋白表达被诱导。在这种情况下，我们发现ARF可以完全滴定所有的 细胞ADAR 1转化为ARF复合物。我们将检验ARF机械地捕获 在核仁中的ADAR 1，以防止ADAR 1抑制I型干扰素途径。在Aim中 2、我们提供了TNBC细胞对ADAR 1缺失敏感的数据。重要的是，这种敏感性 依赖于I型干扰素信号。我们将检验IFN的激活 产生和信号传导将与ADAR 1耗竭结合联合收割机，在体外产生合成致死性 和体内。我们将利用IFN途径的激动剂和合成的ARF肽模拟物。 在目标3中，我们将评估ARF-ADAR 1相互作用如何影响肿瘤微环境。 虽然I型IFN释放是抗病毒应答的主要成分，但慢性IFN-γ释放是抗病毒应答的主要成分。 肿瘤细胞对PD-L1表达的影响 细胞我们将检验I型IFN途径通过阿达尔耗竭而过度活化的假设。 将导致肿瘤浸润淋巴细胞的增加并引发抗肿瘤免疫应答， 可以防止肿瘤转移这些研究对于提供治疗癌症的新方法至关重要。 TNBC通过激活肿瘤微环境中的IFN信号传导。

PROJECT SUMMARY Triple-negative breast cancer (TNBC) has remained a considerable clinical challenge due to the lack of efficacious genetic targets. We need unique effective therapies and accurate biomarkers that can be used to predict patient responses in TNBC. We find that the ARF tumor suppressor is lost alongside p53 mutation in 60% of TNBC. Potentially stemming from the dual loss of ARF and p53, we have observed that type I IFN signaling is elevated in TNBC. We show that this IFN production is being kept in check by the ADAR1 enzyme. Notably, we discovered that ADAR1 is a novel binding partner for ARF. The central premise of this proposal is that the novel ARF-ADAR1 interaction provides key insights into how these two proteins function in the etiology of TNBC. The research application focuses on the role of this interaction in regulating the type I interferon response and sensitizing TNBC cells to cell death and immune recognition. The overarching hypothesis of the proposed research is that loss of ARF and p53 results in elevated type I IFN signaling and sensitizes cells to ADAR1 depletion. In Aim 1, we will define the functional interaction of ARF and ADAR1. In the absence of functional p53, ARF protein expression is induced. In this setting, we find that ARF can fully titrate all the cellular ADAR1 into ARF complexes. We will test the hypothesis that ARF mechanistically traps ADAR1 in the nucleolus to prevent ADAR1 from repressing the type I interferon pathway. In Aim 2, we present data that TNBC cells are sensitive to ADAR1 depletion. Importantly, this sensitivity is dependent on type I interferon signaling. We will test the hypothesis that activation of IFN production and signaling will combine with ADAR1 depletion to produce synthetic lethality in vitro and in vivo. We will utilize both agonists of the IFN pathway and synthetic ARF peptide mimics. In Aim 3, we will assess how the ARF-ADAR1 interaction influences the tumor microenvironment. While type I IFN release is a major component of the anti-viral response, chronic IFN- release by tumor cells can both alter the local immune environment and expression of PD-L1 on tumor cells. We will test the hypothesis that hyperactivation of the type I IFN pathway by ADAR depletion will result in gains in tumor infiltrating lymphocytes and elicit an anti-tumor immune response that will prevent metastasis. These studies are paramount to informing new approaches in treating TNBC through activation of IFN signaling in the tumor microenvironment.