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

• 批准号: 10357886
• 负责人: TOMASZ SKORSKI
• 金额: $ 38.8万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 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/10357886
• 关键词: ABL1 gene; Accelerated Phase; Acute Lymphocytic Leukemia; Apoptotic; Award; BRCA deficient; BRCA1 gene; BRCA2 gene; Biological; Blast Phase; Bone Marrow; Cells; Chronic Lymphocytic Leukemia; 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; Pharmacology; Philadelphia Chromosome; 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; precision medicine; repaired; response; tumor

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）在慢性期（CML-CP）中诱导慢性髓样白血病和 费城染色体阳性急性淋巴细胞白血病（pH+ALL）。 CML-CP可能 发展到更高级的加速阶段（CML-AP），然后是 侵略性爆炸阶段（CML-BP）。大多数CML/pH+目前所有患者均接受治疗 酪氨酸激酶抑制剂（TKIS），例如伊马替尼，达沙替尼和尼洛替尼。但是，它 由于存在TKI-RECTRACTORY，TKI不太可能“治愈” CML/pH+所有患者 细胞（例如静态LSC），抗TKI耐药细胞（例如，携带BCR-ABL1的LSC增殖的LSC 激酶T315i突变体）和LSC携带其他体细胞突变。因此，新颖的治疗方法 在响应中，需要辐射tki frActory/耐药性CML/pH+所有细胞需要模态。 患者并治疗对TKI不好反应的患者。 CML/pH+所有细胞累积了更多的DNA双链断裂（DSB），这是最致命的DNA 病变比正常的病变。白血病细胞可以忍受大量的DSB，因为 修复机制改变并过度激活。因此，CML/pH+所有细胞都“上瘾” 这些途径可以从大量致命的DSB中生存促凋亡的挑战。那里 是正常和BCR-ABL1白血病细胞中DSB修复之间的关键差异。 扩散的LSC通常采用RAD52依赖性DSB维修和PARP1依赖性 替代性非理论最终连接（Alt-Nhej），而正常使用 BRCA1/2介导的同源重组（HR）和DNA-PKCS依赖性NHEJ（D-NHEJ）。静止 LSC使用PARP1介导的Alt-NHEJ代替DNA-PKC –依赖性D-NHEJ，这在 正常静止的HSC。 先前奖项支持的研究表明，遗传和药物 靶向PARP1和/或RAD52对BCR-ABL1 - 阳性执行的合成致死效应 白血病。但是，通常在CMLS/pH+Alls中检测到的体细胞突变不反应有利 到TKI和/或进入更恶性的阶段可以调节对PARP1和/或的响应 RAD52抑制。 我们发现DNA聚合酶theta（由POLQ编码）在 微型学介导的最终连接（MMEJ），Alt-Nhej的一个分支。我们指示的初步数据 该polθ对于BCR-ABL1介导的白血病生成至关重 CML/pH+所有细胞。 AIM＃1旨在确定是否/BCR-ABL1介导的信号修饰符POLθ是否 为了调节其生物学活性并查明polθ在CML和pH+中的作用 细胞。 AIM＃2将优化POLθ抑制剂（POLθI）适合体内使用。 AIM＃3是 专注于Polθ和/或Parp1和Rad52的遗传和药物靶向 和TKI处理的CMLS/pH+在体外条件中模仿外周血和骨骼 骨髓微环境和人体化免疫缺陷小鼠的体内含有原发性白血病 异种移植物。