Identifying determinants of ADAR-dependency in triple-negative breast cancer

项目总结 三阴性乳腺癌(TNBC)是最致命的乳腺癌形式，影响黑人/非洲人 美国女性的比例是白人女性的两倍。此外，TNBC的存活率在#年较低 黑人/非洲女性。为了解决与TNBC相关的差异，我们需要广泛适用的目标 治疗。如果没有靶向治疗，临床医生只能接受化疗，这有许多负面影响。 在许多情况下，对TNBC的治疗最终是无效的。我们观察到一个子集 的表达依赖于作用于RNA的腺苷脱氨酶(ADAR)。阿达尔 是一种将RNA中的腺苷核苷酸转化为肌苷的酶，这个过程被称为A-to-I编辑。损失 ADAR的作用可抑制部分TNBC细胞系的细胞增殖和肿瘤形成。因为ADAR是 是某些TNBC细胞系生长所必需的，是治疗肿瘤的有价值的治疗靶点。 TNBC。已经观察到依赖ADAR的细胞系有干扰素信号的升高，潜在地 这使得对依赖ADAR的肿瘤进行分类成为可能。干扰素信号在黑人/非裔美国人中更高 乳腺肿瘤比白人患者中的肿瘤，这可能使针对ADAR的治疗对 黑人/非裔美国人患者。对ADAR的依赖有一些我们不了解的方面。为 例如，我们不理解为什么一些细胞依赖于ADAR表达，而另一些细胞则不依赖。这里 我们将探索ADAR依赖的机制，并基于以下方面制定治疗TNBC的策略 阿达尔抑制。在目标1中，我们将确定依赖ADAR所需的因素，包括 鉴定导致ADAR耗竭所致表型的免疫原性RNA。在AIM 2中 我们将开发和评估一个分类模型来预测哪些肿瘤将对ADAR抑制敏感。 分类模型的准确性将通过敲除患者来源的异种移植物中的ADAR来评估 TNBC的模型。重要的是，这一目标将为PI提供乳腺癌小鼠模型的训练， 包括肿瘤植入和监测。最后，在AIM 3中，我们将开发一个高通量的A-to-I编辑 检测并用它鉴定ADAR的一个小分子抑制剂。除了可能识别出一种 ADAR的小分子抑制剂，这将为PI开发高通量的 筛选和使用DNA编码的化学库。这项工作将增进我们对ADAR的理解-- 因此，我们可以准确地对依赖ADAR的TNBC进行分类，从而打开治疗的大门 这种致命的乳腺癌形式与AIM 3中确定的小分子有关。开发有效的靶向 TNBC的治疗对于减少这种疾病对黑人/非裔美国人的不同影响至关重要 女人。最后，这笔补助金中包括的研究和职业发展培训将促进私人投资 转变为一名独立的调查员。

PROJECT SUMMARY Triple-negative breast cancer (TNBC), the deadliest form of breast cancer, affects Black/African American women at twice the rate of white women. Additionally, the survival rate for TNBC is lower in Black/African women. To address the disparities associated with TNBC we need broadly applicable targeted therapies. Without targeted therapies, clinicians are left with chemotherapy, which has many negative side- effects and in many cases is ultimately ineffective in the treatment of TNBC. We have observed that a subset of TNBC cell lines are dependent on the expression of Adenosine Deaminase Acting on RNA (ADAR). ADAR is an enzyme that converts adenosine nucleotides in RNA to inosine in a process known as A-to-I editing. Loss of ADAR inhibits cellular proliferation and tumor formation for a subset of TNBC cell lines. Because ADAR is required for the growth of some TNBC cell lines it serves as a valuable therapeutic target for the treatment of TNBC. It has been observed that ADAR-dependent cell lines have elevated interferon signaling, potentially making it possible to classify ADAR-dependent tumors. Interferon signaling is higher in Black/African American breast tumors than tumors in white patients, which may make therapies targeting ADAR more effective for Black/African American patients. There are aspects of ADAR-dependence that we do not understand. For instance, we do not understand why some cells are dependent on ADAR expression while others are not. Here we will explore the mechanism of ADAR-dependency and develop a strategy for treatment of TNBC based on ADAR inhibition. In AIM 1 we will identify the factors that are required for ADAR-dependence, including identification of the immunogenic RNAs that contribute to the phenotype caused by ADAR depletion. In AIM 2 we will develop and assess a classification model to predict which tumors will be sensitive to ADAR inhibition. The accuracy of the classification model will be evaluated by knockdown of ADAR in patient derived xenograft models of TNBC. Importantly this AIM will provide the PI with training in mouse models of breast cancer, including tumor implantation and monitoring. Finally, in AIM 3, we will develop a high-throughput A-to-I editing assay and use it to identify a small molecule inhibitor of ADAR. In addition to the potential identification of a small molecule inhibitor of ADAR, this AIM will provide the PI with experience developing a high-throughput screen and the use of DNA-encoded chemical libraries. This work will advance our understanding of ADAR- dependency such that we can accurately classify ADAR-dependent TNBC, thus opening the door to treating this deadly form of breast cancer with the small molecules identified in AIM 3. Developing an effective targeted therapy for TNBC is essential to reducing the disparate effects of this disease on Black/African American women. Finally, the research and career development training included in this grant will facilitate the PIs transition into an independent investigator.