Targeting DNA repair to eradicate TKi-refractory/resistant CML and Ph+ALL

靶向 DNA 修复以根除 TKi 难治性/耐药性 CML 和 Ph ALL

基本信息

批准号：
10592287
负责人：
TOMASZ SKORSKI
金额：
$ 38.96万
依托单位：
TEMPLE UNIV OF THE COMMONWEALTH
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-08-12 至 2025-02-28
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10592287
关键词：
ABL1 gene Accelerated Phase Acute Lymphocytic Leukemia Apoptotic Award BRCA deficient BRCA1 gene BRCA2 gene Biological Blast Phase Bone Marrow Cell Proliferation Cells Chronic Myeloid Leukemia Chronic Phase Collaborations DNA Double Strand Break DNA Repair DNA Repair Pathway DNA lesion DNA-Directed DNA Polymerase DNA-PKcs DNA-dependent protein kinase Dasatinib Data Defect Disease Double Strand Break Repair Genetic Genetic Transcription Hematopoietic stem cells Imatinib Immunodeficient Mouse In Vitro LIG4 gene Leukemic Cell Malignant - descriptor Malignant neoplasm of ovary Mediating Modality Mutation Nonhomologous DNA End Joining Oncogenic Pathway interactions Patients Ph+ ALL Philadelphia Chromosome Philadelphia Chromosome Positive Chronic Myelogenous Leukemia Phosphotransferases Play Proliferating Protein Tyrosine Kinase Proto-Oncogene Proteins c-abl RAD52 gene Refractory Reporting Research Support Resistance Role Signal Transduction Somatic Mutation Testing Therapeutic Therapeutic Effect Tyrosine Kinase Inhibitor Work Xenograft procedure acute lymphoblastic leukemia cell brca gene cancer cell design homologous recombination improved improved outcome in vivo inhibitor leukemia leukemic stem cell leukemogenesis malignant breast neoplasm mutant new therapeutic target novel novel therapeutics peripheral blood personalized medicine pharmacologic precision medicine repaired response tumor

项目摘要

Oncogenic BCR-ABL1 tyrosine kinase transforms hematopoietic stem cells (HSCs) to leukemia stem cells (LSCs) to induce chronic myeloid leukemia in chronic phase (CML-CP) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL). CML-CP may progress to more advanced accelerated phase (CML-AP), and subsequently to a very aggressive blast phase (CML-BP). Most CML/Ph+ALL patients are currently treated with tyrosine kinase inhibitors (TKis) such as imatinib, dasatinib and nilotinib. However, it is unlikely that TKis will “cure” CML/Ph+ALL patients due to the presence of TKi-refractory cells (e.g., quiescent LSCs), TKi-resistant cells (e.g., proliferating LSCs carrying BCR-ABL1 kinase T315I mutant) and LSCs carrying additional somatic mutations. Therefore, novel treatment modalities are needed to eradicate TKi-refractory/resistant CML/Ph+ALL cells in the responding patients and to treat patients who do not respond favorably to TKis. CML/Ph+ALL cells accumulate more DNA double strand breaks (DSBs), the most lethal DNA lesions, than normal counterparts. Leukemia cells can tolerate high numbers of DSBs because the repair mechanisms are altered and hyper-activated. Therefore, CML/Ph+ALL cells are “addicted” to these pathways to survive pro-apoptotic challenge from high numbers of lethal DSBs. There are critical differences between DSB repair in normal and BCR-ABL1 leukemia cells. Proliferating LSCs usually employ RAD52-dependent DSB repairs and PARP1 –dependent alternative non-homologous end-joining (Alt-NHEJ), whereas normal counterparts use BRCA1/2-mediated homologous recombination (HR) and DNA-PKcs –dependent NHEJ (D-NHEJ). Quiescent LSCs use PARP1-mediated Alt-NHEJ instead of DNA-PKcs –dependent D-NHEJ, which is predominant in normal quiescent HSCs. Research supported by previous award demonstrated that genetic and pharmacological targeting of PARP1 and/or RAD52 exerted synthetic lethal effect against BCR-ABL1 –positive leukemias. However, somatic mutations often detected in CMLs/Ph+ALLs not responding favorably to TKi and/or progressing to more malignant stages can modulate the response to PARP1 and/or RAD52 inhibition. We have discovered that DNA polymerase theta (Polθ, encoded by POLQ) plays a vital role in microhomology-mediated end-joining (MMEJ), a branch of Alt-NHEJ. Our preliminary data indicate that Polθ is essential for BCR-ABL1 –mediated leukemogenesis and that targeting of Polθ eliminated CML/Ph+ALL cells. Aim #1 is designed to determine if/how BCR-ABL1 –mediated signaling modifies Polθ to regulate its biological activities and to pinpoint the role of Polθ in CML and Ph+ALL stem cells. Aim #2 will optimize Polθ inhibitor (Polθi) to be suitable for in vivo use. Aim #3 is focused on genetic and pharmacological targeting of Polθ and/or PARP1 and RAD52 against TKi-naive and TKi-treated CMLs/Ph+ALLs in in vitro conditions mimicking peripheral blood and bone marrow microenvironment and also in vivo in humanized immunodeficient mice bearing primary leukemia xenografts.

致癌性 BCR-ABL1 酪氨酸激酶将造血干细胞 (HSC) 转化为白血病干细胞细胞（LSC）诱导慢性粒细胞白血病慢性期（CML-CP）和费城染色体阳性急性淋巴细胞白血病 (Ph+ALL) 可能。进展到更高级的加速阶段（CML-AP），随后进入非常严重的阶段大多数 CML/Ph+ALL 患者目前正在接受治疗。酪氨酸激酶抑制剂（TKis），例如伊马替尼、达沙替尼和尼洛替尼。由于存在 TKi 难治性，TKis 不太可能“治愈”CML/Ph+ALL 患者细胞（例如，静态 LSC）、TKi 耐药细胞（例如，携带 BCR-ABL1 的增殖 LSC）激酶 T315I 突变体）和携带额外体细胞突变的 LSC 因此是新的治疗方法。需要采取一些方法来根除应答中 TKi 难治性/耐药性 CML/Ph+ALL 细胞患者并治疗对 TK 没有良好反应的患者。 CML/Ph+ALL 细胞积累更多 DNA 双链断裂 (DSB)，这是最致命的 DNA 白血病细胞比正常分子更能耐受大量 DSB，因为修复机制被改变并过度激活，因此，CML/Ph+ALL 细胞“上瘾”。这些途径可以在来自大量致命 DSB 的促凋亡挑战中生存下来。是正常细胞和 BCR-ABL1 白血病细胞中 DSB 修复之间的关键差异。增殖的LSC通常采用RAD52依赖性DSB修复和PARP1依赖性替代非同源末端连接（Alt-NHEJ），而正常臂使用 BRCA1/2 介导的同源重组 (HR) 和 DNA-PKcs 依赖性 NHEJ (D-NHEJ)。 LSCs 使用 PARP1 介导的 Alt-NHEJ，而不是 DNA-PKcs 依赖的 D-NHEJ，后者在正常静止的 HSC。先前奖项支持的研究表明，遗传和药理学 PARP1 和/或 RAD52 的靶向对 BCR-ABL1 阳性发挥合成致死作用然而，在 CML/Ph+ALL 中经常检测到的体细胞突变反应不佳。对 TKi 和/或进展到更恶性的阶段可以调节对 PARP1 和/或的反应 RAD52 抑制。我们发现 DNA 聚合酶 theta（Polθ，由 POLQ 编码）在我们的初步数据表明，微同源介导的末端连接（MMEJ）是 Alt-NHEJ 的一个分支。 Polθ 对于 BCR-ABL1 介导的白血病发生至关重要，并且 Polθ 的靶向被消除 CML/Ph+ALL 细胞旨在确定 BCR-ABL1 介导的信号传导是否/如何改变 Polθ。调节其生物活性并查明 Polθ 在 CML 和 Ph+ALL 干细胞中的作用目标#2 将优化 Polθ 抑制剂 (Polθi)，使其适合体内使用。专注于针对 TKi-naive 的 Polθ 和/或 PARP1 和 RAD52 的遗传和药理学靶向和 TKi 治疗的 CML/Ph+ALL 在模拟外周血和骨骼的体外条件下骨髓微环境以及患有原发性白血病的人源化免疫缺陷小鼠的体内异种移植物。