Genomic instability causes imatinib resistance in CML

Bcr/abl基因起源于t（9;22）相互易位，存在于大多数慢性粒细胞性白血病（CML）中。 白血病（CML）和急性淋巴细胞白血病（ALL）患者队列。BCR/ABL致癌酪氨酸 激酶调节对DNA损伤的应答，诱导对遗传毒性疗法的抗性。此外，BCR/ABL 刺激基因组不稳定性，可能导致BCR/ABL激酶突变，导致伊马替尼耐药 甲磺酸盐 我们假设：BCR/ABL升高了活性氧（ROS）的水平， “自发”DNA损伤（例如尿嘧啶残基），其不忠实修复引入氨基酸 BCR/ABL激酶结构域中的取代导致对IM的抗性。 活性氧在DNA氧化损伤中的作用导致突变和伊马替尼耐药 将在CML造血干细胞（HSC）、普通髓系祖细胞（CMP）和 粒细胞/巨噬细胞祖细胞（GMP）使用抗氧化剂的方法和在体外和体内模型 BCR/ABL白血病 BCR/ABL中ROS依赖性DNA氧化损伤机制的有效性和保真度 白血病细胞将通过研究碱基切除修复（BER）来确定，重点是UDG糖基化酶 除去尿嘧啶残基。这些反应将使用定义明确的报告基因/底物系统进行检查， 不同方法的组合，包括免疫荧光、无磷酸化和相互作用， 剥夺突变体，转基因小鼠和测序。将研究BCR/ABL-UDG功能相互作用 通过诱变并通过适体靶向以抑制对甲磺酸伊马替尼的抗性。

Bcr/abl gene is derived from the t(9;22) reciprocal translocation and is present in most of chronic myelogenous leukemia (CML) and a cohort of acute lymphoblastic leukemia (ALL) patients. BCR/ABL oncogenic tyrosine kinase modulates response to DNA damage inducing resistance to genotoxic therapies. In addition BCR/ABL stimulates genomic instability, which may lead to mutations in BCR/ABL kinase causing resistance to imatinib mesylate. We hypothesize that: BCR/ABL elevates the levels of reactive oxygen species (ROS) which induce "spontaneous" DNA lesions (for example uracil residues), whose unfaithful repair introduces amino acid substitutions in the BCR/ABL kinase domain causing resistance to IM. The role of ROS in generation of oxidative DNA damage leading to mutagenesis and resistance to imatinib mesylate will be studied in CML hematopoietic stem cells (HSC), common myeloid progenitor cells (CMP), and granulocyte/macrophage progenitor cells (GMP) using anti-oxidant approaches and in vitro and in vivo models of BCR/ABL leukemogenesis. The efficiency and fidelity of the mechanisms processing ROS-dependent oxidative DNA damage in BCR/ABL leukemia cells will be determined by studying base excision repair (BER), focusing on UDG glycosylase removing uracil residues. These reactions will be examined using well-defined reporter/substrate systems and a combination of different approaches including immunofluorescence, phosphorylation-less and interaction- deprived mutants, transgenic mice, and sequencing. BCR/ABL-UDG functional interaction will be investigated by mutagenesis and targeted by aptamers to inhibit resistance to imatinib mesylate.