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

项目总结 三阴性乳腺癌(TNBC)仍然是一个相当大的临床挑战，因为 缺乏有效的基因靶点。我们需要独特有效的治疗方法和准确的生物标志物。 这可以用来预测患者对TNBC的反应。我们发现ARF肿瘤抑制因子 在60%的TNBC中，随着P53突变而丢失。可能源于ARF的双重损失 和P53，我们观察到在TNBC中I型干扰素信号升高。我们发现这种干扰素 生产受到ADAR1酶的控制。值得注意的是，我们发现ADAR1是 一种新型的ARF结合伙伴。这项提议的中心前提是，新的ARF-ADAR1 相互作用为这两种蛋白在TNBC的病因学中如何发挥作用提供了关键的见解。这个 研究应用侧重于这种相互作用在调节I型干扰素中的作用 反应并使TNBC细胞对细胞死亡和免疫识别敏感。最重要的是 建议研究的假设是ARF和P53的缺失导致I型干扰素升高 信号转导并使细胞对ADAR1耗尽敏感。 在目标1中，我们将定义ARF和ADAR1的功能相互作用。在没有功能的情况下 诱导P53、ARF蛋白表达。在这种情况下，我们发现ARF可以完全滴定所有的 细胞内的ADAR1转化为ARF复合体。我们将检验ARF机械陷阱的假设 核仁中的ADAR1，以防止ADAR1抑制I型干扰素途径。在AIM 2，我们提出了TNBC细胞对ADAR1耗竭敏感的数据。重要的是，这种敏感性 依赖于I型干扰素信号。我们将检验这样一个假设，即干扰素的激活 生产和信号转导将与ADAR1耗尽相结合，在体外产生合成杀伤力 在活体内。我们将利用干扰素途径的激动剂和合成的ARF多肽模拟物。 在目标3中，我们将评估ARF-ADAR1相互作用如何影响肿瘤微环境。 虽然I型干扰素的释放是抗病毒反应的主要成分，但慢性干扰素-的释放 肿瘤细胞可改变局部免疫环境和肿瘤表面PD-L1的表达 细胞。我们将验证一种假设，即通过ADAR耗尽导致I型干扰素途径的过度激活 将导致肿瘤浸润性淋巴细胞的增加，并引发抗肿瘤免疫反应 会防止肿瘤转移。这些研究对于提供新的治疗方法至关重要。 TNBC通过激活肿瘤微环境中的干扰素信号。

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.