"BCR/ABL-PI-3k-ROS pathway induce genomic instability ...."

“BCR/ABL-PI-3k-ROS 通路导致基因组不稳定......”

• 批准号: 7984880
• 负责人: TOMASZ SKORSKI
• 金额: $ 31.54万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7984880
• 关键词: 1-Phosphatidylinositol 3-Kinase; Acute Lymphocytic Leukemia; Amino Acid Substitution; Apoptosis; Appearance; Bcr-Abl tyrosine kinase; Benign; Biological; Biological Assay; Blast Phase; Cell Proliferation; Cells; Chromosomal translocation; Chromosome abnormality; Chronic Myeloid Leukemia; Chronic-Phase Myeloid Leukemia; Complementary DNA; Complex; DNA Repair; Development; Disease; Disease Progression; Dominant-Negative Mutation; Drug resistance; Extracellular Matrix; Figs - dietary; Generations; Genetic; Genomic Instability; Growth Factor; Hematopoietic; Hematopoietic stem cells; Imatinib; Imatinib mesylate; In Vitro; Knockout Mice; Laboratories; Malignant - descriptor; Mediating; Mitochondria; Molecular; Mutation; Myelogenous; NADPH Oxidase; Oncogenes; Oncogenic; Pathway interactions; Patients; Perifosine; Phosphatidylinositols; Play; Point Mutation; Population; Prevention; Production; Protein Tyrosine Kinase; Protein-Serine-Threonine Kinases; Proteins; Reactive Oxygen Species; Reporting; Resistance; Resistance development; Respiratory Chain; Role; Signal Pathway; Small Interfering RNA; Source; Stem cells; Therapeutic Effect; Tyrosine Kinase Inhibitor; Work; bcr-abl Fusion Proteins; cohort; granulocyte; improved; inhibitor/antagonist; leukemia; leukemic stem cell; leukemogenesis; macrophage; mouse model; mutant; novel strategies; oxidative DNA damage; prevent; progenitor; public health relevance; rac GTP-Binding Proteins; research study; small molecule; stem

DESCRIPTION (provided by applicant): Chromosomal translocation t(9;22) is responsible for appearance of an oncogene encoding BCR/ABL fusion tyrosine kinase, which induce chronic myelogenous leukemia (CML) and a cohort of acute lymphocytic leukemia (ALL). CML usually starts as a relatively benign chronic phase (CML-CP), which progresses to an aggressive disease - blast crisis (CML-BC). Malignant transformation of the disease is associated with accumulation of additional genetic errors. Imatinib mesylate (IM), a small molecule inhibitor of BCR/ABL kinase, revolutionized the treatment of CML-CP. Unfortunately patients may develop resistance to the drug caused by point mutations encoding amino acid substitutions in the BCR/ABL kinase domain. In conclusion, CML cells display genomic instability leading to resistance to IM and malignant progression of the disease. This proposal is focused on determination the mechanisms responsible for these phenomena and subsequently on prevention/inhibition of the development of IM resistance and CML-BC. BCR/ABL kinase stimulates numerous signaling pathways to induce and maintain transformation of hematopoietic cells. We, and others found that phosphatidylinositol-3 kinase (PI-3k) play an essential role in growth factor independent proliferation and protection from apoptosis in CML. Here we propose to study the role of PI-3k and its downstream effectors Akt and Rac in genomic instability in CML stem and progenitor cell populations. Using genetic approach (dominant-negative mutants, siRNA, antisense cDNA, knockout mice) and small molecule inhibitors (for example perifosine, NSC23766) we will determine how PI-3k and its downstream effectors generate the reactive oxygen species (ROS), which in turn may cause oxidative DNA damage and facilitate genomic instability. Long-term in vitro culture and mouse models of CML will be applied here. IM resistance will be detected in clonogenic assays and by sequencing BCR/ABL kinase domain, and chromosomal aberrations will be detected by SNPs and SKY. If successfully accomplished, these experiments will determine if PI-3k pathway inhibitors should be used to improve therapeutic effect of IM and prevent/delay CML progression toward lethal blast crisis. PUBLIC HEALTH RELEVANCE: Although tyrosine kinase inhibitors (TKIs) revolutionized the treatment of chronic myelogenous leukemia (CML), patients can develop resistance to the drug and progress toward fatal malignant blast crisis of the disease. Both phenomena are associated with genetic instability caused by oncogenic BCR/ABL kinase. We will investigate the mechanisms responsible for mutations in BCR/ABL kinase causing TKI-resistance and for chromosomal aberrations leading to blast crisis. Molecular mechanisms of BCR/ABL-dependent phosphatidylinositol (PI-3k)-mediated production of reactive oxygen species (ROS) causing oxidative DNA damage, mutations, and chromosomal aberrations will be determined.

描述（由申请人提供）：染色体易位t（9;22）导致编码BCR/ABL融合酪氨酸激酶的癌基因出现，其诱导慢性粒细胞白血病（CML）和急性淋巴细胞白血病（ALL）队列。CML通常以相对良性的慢性期（CML-CP）开始，其进展为侵袭性疾病-原始细胞危象（CML-BC）。疾病的恶性转化与额外遗传错误的积累有关。 甲磺酸伊马替尼（Imatinib mesylate，IM）是一种BCR/ABL激酶的小分子抑制剂，是CML-CP治疗的革命性进展。不幸的是，患者可能会对BCR/ABL激酶结构域中编码氨基酸取代的点突变引起的药物产生耐药性。 总之，CML细胞显示基因组不稳定性，导致对IM的抗性和疾病的恶性进展。该提案的重点是确定负责这些现象的机制，并随后预防/抑制IM耐药性和CML-BC的发展。 BCR/ABL激酶刺激多种信号通路以诱导和维持造血细胞的转化。我们和其他人发现，磷脂酰肌醇-3激酶（PI-3 k）在CML的生长因子非依赖性增殖和细胞凋亡保护中起重要作用。 在这里，我们建议研究PI-3 k及其下游效应Akt和Rac在CML干细胞和祖细胞群体的基因组不稳定性中的作用。使用遗传方法（显性负突变体、siRNA、反义cDNA、敲除小鼠）和小分子抑制剂（例如哌立福新、NSC 23766），我们将确定PI-3 k及其下游效应物如何产生活性氧（ROS），这反过来可能导致氧化DNA损伤并促进基因组不稳定性。本研究将采用慢性粒细胞白血病的长期体外培养和小鼠模型。IM耐药性将通过克隆形成试验和BCR/ABL激酶结构域测序进行检测，染色体畸变将通过SNP和SKY进行检测。 如果成功完成，这些实验将确定PI-3 k通路抑制剂是否应用于改善IM的治疗效果并预防/延迟CML向致死性急变的进展。 公共卫生相关性：虽然酪氨酸激酶抑制剂（TKI）彻底改变了慢性粒细胞白血病（CML）的治疗，但患者可能对药物产生耐药性，并发展为致命的恶性急变。这两种现象都与致癌BCR/ABL激酶引起的遗传不稳定性有关。我们将研究BCR/ABL激酶突变导致TKI耐药和染色体畸变导致急变的机制。将确定BCR/ABL依赖性磷脂酰肌醇（PI-3 k）介导的活性氧（ROS）产生导致氧化性DNA损伤、突变和染色体畸变的分子机制。