RNase H2 is a novel therapeutic target in triple negative breast cancer

RNase H2 是三阴性乳腺癌的新治疗靶点

基本信息

批准号：
10297432
负责人：
Shiaw-Yih Lin
金额：
$ 38.41万
依托单位：
UNIVERSITY OF TX MD ANDERSON CAN CTR
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-07-01 至 2026-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10297432
关键词：
Affect Bioinformatics Breast Cancer Cell Breast Cancer Prevention Breast Cancer Treatment Breast Cancer cell line Breast Epithelial Cells CXCL10 gene Catalytic Domain Cell Death Cell Survival Cell model Cells Characteristics Chemicals Combination immunotherapy Combined Modality Therapy DNA Damage DNA biosynthesis Disease Enzymes Excision Exhibits Genetic Genome Genomic Instability Genomics Goals Immunity Immunotherapy In Vitro Knowledge Maximum Tolerated Dose Mediating Mus Nature Pathway interactions Patient-derived xenograft models of breast cancer Patients Proteins RANTES Recurrence Replication-Associated Process Resistance Ribonucleases Ribonucleotides Role Signal Transduction Small Interfering RNA Stimulator of Interferon Genes T-Lymphocyte Testing Therapeutic Therapeutic Effect Toxic effect Treatment Efficacy Xenograft Model anti-PD-1 anti-PD1 therapy base cancer subtypes chemotherapy cytokine efficacy evaluation follow-up immune checkpoint immune checkpoint blockade in vivo in vivo Model inhibitor/antagonist innovation mouse model new therapeutic target novel overexpression programmed cell death ligand 1 programmed cell death protein 1 replication stress response therapeutically effective triple-negative invasive breast carcinoma tripolyphosphate tumor tumor growth tumor-immune system interactions

项目摘要

Project Summary Due to their hyperproliferative nature and intrinsic genomic instability, triple-negative breast cancer (TNBC) cells exhibit high levels of replication stress, which occurs when the DNA replication machinery encounters obstacles that impede the replication process. How TNBC cells adapt to these high levels of replication stress remains poorly understood. These adaptive mechanisms, if identified, would reveal specific targets in TNBC and provide an effective strategy for TNBC treatment. To this end, we generated innovative cell models and discovered that one major mechanism required for TNBC cells to survive high replication stress is an increase in the enzyme RNase H2. RNase H2 acts to remove ribonucleotides that have been improperly incorporated into the genome, a key driver of replication stress. Subsequent bioinformatic analysis revealed that RNASEH2A, the catalytic subunit of RNase H2, is overexpressed in 89% of TNBC tumors and all the TNBC cell lines that we tested. More importantly, we found that RNase H2 inhibition, by genetic depletion or by the chemical inhibitor R14, specifically kills TNBC cells both in vitro and in vivo with minimal effects on nontumorigenic mammary epithelial cells. These important findings indicate that RNase H2 inhibition may be a promising therapeutic strategy for TNBC treatment. Intriguingly, we also found that RNase H2 inhibition activated the stimulator of interferon genes (STING) pathway and increased expression of key T-cell-attracting cytokines in TNBC cells and sensitized mouse TNBC tumors to anti-PD-1 immunotherapy, suggesting that the therapeutic effects of RNase H2 inhibition may be potentiated by anti-PD-1 therapy. All of these exciting findings support the hypotheses that RNase H2 inhibition offers a promising therapeutic strategy to treat TNBC and that it may be enhanced by anti-PD-1 immunotherapy. These hypotheses will be tested via 3 specific aims: (1) To identify the underlying mechanisms of the therapeutic efficacy of RNase H2 inhibition in TNBC. We will determine if limiting levels of dNTPs leads to increased misincorporation of ribonucleotides into the genomes of TNBC cells, and if inhibition of RNase H2 in TNBC prevents removal of these misincorporated ribonucleotides, consequently leading to unsustainably high replication stress and cell death. We will also evaluate the potential mechanisms mediating the escape of TNBC from RNase H2 inhibition and strategies to overcome resistance. (2) To determine the therapeutic potential of R14 for TNBC treatment. We will determine the in vivo tolerability of R14 in mice to determine the maximum tolerated dose as well as any potential toxicities. We will then assess the efficacy of R14 treatment in 10 TNBC patient-derived xenograft models representative of 5 TNBC subtypes. (3) To determine the therapeutic efficacy of the combination of RNase H2 inhibition with PD-1 immunotherapy in TNBC. We will evaluate the therapeutic efficacy of the R14/PD-1 immunotherapy combination in TNBC using 5 syngeneic TNBC mouse models. We will also assess if and how R14-mediated therapies affect the tumor immune microenvironment.

项目概要由于其过度增殖性质和内在基因组不稳定性，三阴性乳腺癌 (TNBC) 细胞表现出高水平的复制应激，当 DNA 复制机器遇到阻碍复制过程的障碍。 TNBC 细胞如何适应这些高水平的复制压力仍然知之甚少。这些适应性机制如果被发现，将揭示 TNBC 中的特定目标为TNBC治疗提供有效策略。为此，我们生成了创新的细胞模型并发现 TNBC 细胞在高复制压力下生存所需的一个主要机制是增加在 RNase H2 酶中。 RNase H2 可去除不正确掺入的核糖核苷酸进入基因组，这是复制压力的关键驱动因素。随后的生物信息学分析表明 RNASEH2A 是 RNase H2 的催化亚基，在 89% 的 TNBC 肿瘤和所有 TNBC 中过表达我们测试的细胞系。更重要的是，我们发现 RNase H2 抑制可通过基因缺失或通过化学抑制剂 R14，在体外和体内特异性杀死 TNBC 细胞，对非致瘤性乳腺上皮细胞。这些重要的发现表明 RNase H2 抑制可能是 TNBC 治疗的一种有前景的治疗策略。有趣的是，我们还发现 RNase H2 抑制激活干扰素基因刺激剂 (STING) 通路并增加关键 T 细胞吸引的表达 TNBC 细胞中的细胞因子并使小鼠 TNBC 肿瘤对抗 PD-1 免疫疗法敏感，这表明抗 PD-1 疗法可能会增强 RNase H2 抑制的治疗效果。所有这些都令人兴奋研究结果支持以下假设：RNase H2 抑制提供了一种有前途的治疗策略 TNBC 可能会通过抗 PD-1 免疫疗法得到增强。这些假设将通过 3 具体目标：(1) 确定 RNase H2 抑制治疗功效的潜在机制 TNBC。我们将确定 dNTP 的限制水平是否会导致核糖核苷酸的错误掺入增加进入 TNBC 细胞的基因组，并且如果抑制 TNBC 中的 RNase H2 可以阻止这些细胞的去除错误掺入核糖核苷酸，从而导致不可持续的高复制压力和细胞死亡。我们还将评估介导 TNBC 逃脱 RNase H2 抑制的潜在机制，克服阻力的策略。 (2) 确定R14用于TNBC治疗的治疗潜力。我们将确定 R14 在小鼠体内的耐受性，以确定最大耐受剂量以及任何潜在剂量毒性。然后我们将评估 R14 治疗在 10 个 TNBC 患者来源的异种移植模型中的疗效 5个TNBC亚型的代表。 (3) 确定RNase H2组合的治疗效果 TNBC 中 PD-1 免疫疗法的抑制作用。我们将评估R14/PD-1的治疗效果使用 5 个同基因 TNBC 小鼠模型进行 TNBC 免疫治疗组合。我们还将评估是否以及如何 R14 介导的疗法影响肿瘤免疫微环境。