Targeting Wnt/Ca2+ Pathway components and Bcr-Abl for the treatment of CML

描述（由申请人提供）：慢性髓性白血病（CML）和大约20%的急性淋巴细胞白血病（ALL）以表达具有组成型酪氨酸激酶活性的致癌融合蛋白Bcr-Abl为特征。选择性Bcr-Abl拮抗剂甲磺酸伊马替尼（格列卫）是一种小分子酪氨酸激酶抑制剂，已被证明在治疗CML中非常有效。虽然伊马替尼治疗有效，但通常不能治愈。伊马替尼不能完全消除Bcr-Abl+细胞，并且由于伊马替尼耐药性的发展，疾病经常复发。此外，Bcr-Abl+ ALL对伊马替尼治疗难治性。靶向其他基因产物可能增强伊马替尼消除CML和Bcr-Abl+ ALL细胞的功效，并导致完全根除疾病。我们设计了一个使用RNA干扰（RNAi）的无偏功能丧失筛选来识别这些基因。我们利用全基因组慢病毒小发夹RNA （shRNA）文库结合微阵列分析来鉴定基因靶点，当被抑制时，伊马替尼会增强Bcr-Abl+细胞的杀伤。我们的筛选发现了多个基因，这些基因是非典型Wnt/钙信号通路的组成部分，其生物学作用尚不清楚。我们计划进一步分析这些基因，以确定它们的失活是否与伊马替尼在体外和CML和Bcr-Abl+ ALL小鼠模型中有效地协同杀死Bcr-Abl+细胞。

DESCRIPTION (provided by applicant): Chronic myeloid leukemia (CML) and about 20% of acute lymphoblastic leukemias (ALL) are characterized by expression of the oncogenic fusion protein Bcr-Abl that has constitutive tyrosine kinase activity. The selective Bcr-Abl antagonist imatinib mesylate (Gleevec) is a small molecule tyrosine kinase inhibitor that has proven highly effective in the treatment of CML. Although effective, imatinib therapy is usually not curative. Imatinib fails to completely eliminate Bcr-Abl+ cells and the disease often relapses due to development of imatinib resistance. Also, Bcr-Abl+ ALL is refractory to treatment with imatinib. Targeting additional gene products may enhance the efficacy of imatinib in eliminating CML and Bcr-Abl+ ALL cells and lead to complete eradication of disease. We have designed an unbiased loss-of-function screen using RNA interference (RNAi) to identify such genes. We utilized a genome-wide lentiviral small hairpin RNA (shRNA) library in combination with microarray analysis to identify gene targets that, when inhibited, potentiate Bcr-Abl+ cell killing by imatinib. Our screen identified multiple genes that are components of a noncanonical Wnt/calcium signaling pathway whose biological role is poorly understood. We plan to further analyze these genes to determine if their inactivation effectively cooperates with imatinib in killing Bcr-Abl+ cells in vitro and in mouse models of CML and Bcr-Abl+ ALL.