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

染色体易位t（9;22）导致编码BCR/ABL融合的癌基因的出现 酪氨酸激酶，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。 白血病（ALL）。CML通常以相对良性的慢性期（CML-CP）开始，其进展为慢性期。 侵袭性疾病-急变（CML-BC）。疾病的恶性转化与 积累更多的遗传错误。 甲磺酸伊马替尼（IM），一种BCR/ABL激酶的小分子抑制剂，彻底改变了治疗 CML-CP。不幸的是，患者可能会对药物产生耐药性， BCR/ABL激酶结构域中的氨基酸取代。 总之，CML细胞显示基因组不稳定性，导致对IM和恶性肿瘤的抗性。 疾病的进展。这项建议的重点是确定负责这些问题的机制。 这种现象的影响以及随后对预防/抑制IM抗性和CML-BC的发展的影响。 BCR/ABL激酶刺激多种信号传导途径以诱导和维持BCR/ABL的转化。 造血细胞我们和其他人发现，磷脂酰肌醇-3激酶（PI-3 k）在 CML中生长因子非依赖性增殖和保护免于凋亡。 本研究拟探讨PI-3 k及其下游效应子Akt和Rac在基因组中的作用， CML干细胞和祖细胞群体的不稳定性。利用遗传学方法（显性-阴性突变体， siRNA、反义cDNA、敲除小鼠）和小分子抑制剂（例如哌立福辛、NSC 23766）， 将决定PI-3 k及其下游效应物如何产生活性氧（ROS）， turn可能导致氧化性DNA损伤并促进基因组不稳定性。长期体外培养和小鼠 CML的模型将在这里应用。IM耐药性将通过克隆形成试验和测序进行检测 BCR/ABL激酶结构域和染色体畸变将通过SNP和SKY检测。 如果成功完成，这些实验将确定PI-3 k通路抑制剂是否应该被用于治疗。 用于提高IM的治疗效果，预防/延缓CML向致死性急变的进展。

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.