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

• 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
• 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

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.

项目摘要 由于其过度增殖的性质和内在的基因组不稳定性，三阴性乳腺癌（TNBC） 细胞表现出高水平的复制应激，当DNA复制机制遇到 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。这些适应机制，如果确定，将揭示TNBC的具体目标 为TNBC的治疗提供了有效的策略。为此，我们创建了创新的细胞模型， 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的作用是去除不适当掺入的核糖核苷酸 复制压力的关键驱动因素。随后的生物信息学分析显示， RNA酶H2的催化亚基RNASEH 2A在89%的TNBC肿瘤中过表达，所有TNBC肿瘤中均过表达。 我们测试的细胞系。更重要的是，我们发现RNA酶H2抑制，通过基因耗竭或通过 化学抑制剂R14在体外和体内特异性杀死TNBC细胞，对TNBC细胞的影响最小。 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因子（STING）通路，并增加关键T细胞吸引因子的表达。 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 RNA酶H2抑制的治疗效果可以通过抗PD-1治疗来增强。所有这些令人兴奋的 研究结果支持了以下假设，即RNase H2抑制提供了一种有前途的治疗策略， TNBC，并且可以通过抗PD-1免疫疗法增强。这些假设将通过3 具体目的：（1）确定RNase H2抑制治疗效果的潜在机制， TNBC。我们将确定限制dNTPs水平是否会导致核糖核苷酸错误掺入的增加 并且如果TNBC中RNase H2的抑制阻止了这些RNA酶的去除， 错误掺入的核糖核苷酸，从而导致不可持续的高复制应激和细胞死亡。 我们还将评估介导TNBC逃避RNA酶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在小鼠中的体内耐受性，以确定最大耐受剂量以及任何潜在的 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物模型中的功效 代表5种TNBC亚型。(3)为了确定RNA酶H2和RNA酶H3的组合的治疗功效， 用PD-1免疫疗法抑制TNBC。我们将评估R14/PD-1的治疗效果 使用5种同基因TNBC小鼠模型在TNBC中进行免疫治疗组合。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。