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

项目摘要 三阴性乳腺癌（TNBC）是最致命的乳腺癌形式，影响黑人/非洲人 美国女性的死亡率是白色女性的两倍。此外，TNBC的存活率较低， 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，化疗有许多负面影响- 在许多情况下，它在TNBC的治疗中最终无效。我们观察到， TNBC细胞系的增殖依赖于作用于RNA的腺苷脱氨酶（阿达尔）的表达。阿达尔 是一种将RNA中的腺苷核苷酸转化为肌苷的酶，其过程称为A到I编辑。损失 的阿达尔抑制TNBC细胞系亚群的细胞增殖和肿瘤形成。因为阿达尔是 它是一些TNBC细胞系生长所需的，它作为治疗TNBC的有价值的治疗靶点。 TNBC。已经观察到ADAR依赖性细胞系具有升高的干扰素信号传导，潜在地 从而可以对依赖ADAR的肿瘤进行分类。干扰素信号在黑人/非裔美国人中更高 乳腺肿瘤比白色患者中的肿瘤，这可能使靶向阿达尔的治疗更有效， 黑人/非裔美国人患者。ADAR依赖性的某些方面我们还不了解。为 例如，我们不明白为什么有些细胞依赖于阿达尔表达，而另一些则不依赖。这里 我们将探索ADAR依赖性的机制，并根据以下方面制定治疗TNBC的策略： 阿达尔抑制。在AIM 1中，我们将确定ADAR依赖性所需的因素，包括 鉴定促成由阿达尔耗竭引起的表型的免疫原性RNA。在AIM 2中 我们将开发和评估一种分类模型来预测哪些肿瘤对阿达尔抑制敏感。 将通过敲低患者来源的异种移植物中的阿达尔来评价分类模型的准确性 TNBC的模式。重要的是，该AIM将为PI提供乳腺癌小鼠模型的培训， 包括肿瘤植入和监测。最后，在AIM 3中，我们将开发一种高通量的A-to-I编辑 测定并将其用于鉴定阿达尔的小分子抑制剂。除了可能识别出 作为阿达尔的小分子抑制剂，该AIM将为PI提供开发高通量 筛选和使用DNA编码的化学文库。这项工作将促进我们对阿达尔的了解- 依赖性，这样我们就可以准确地对ADAR依赖性TNBC进行分类，从而为治疗ADAR依赖性TNBC打开了大门。 这种致命的乳腺癌与AIM 3中鉴定的小分子有关。制定有效的目标 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 妇女最后，该补助金中包含的研究和职业发展培训将为PI提供便利 转型为独立调查员

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.