NEGATIVE REGULATION OF THE YEAST MRP, YCF1P, AND THE HUMAN MRPS BY CK2

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 对于Ph+阳性的高危急性淋巴细胞白血病患者的治疗，多年来一直是非常困难的。最近，这些患者的标准高CVAD(环磷酰胺、长春新碱、地塞米松和阿霉素)治疗被修改为包括格列卫(伊马替尼)。伊马替尼的加入非常成功，将完全缓解(CR)率从60%提高到96%，两年存活率从85%的约40%提高到约40%。伊马替尼提高治疗效果的机制尚不清楚。环磷酰胺代谢产物、阿霉素和长春新碱都是多药耐药蛋白1(MRP1/ABCC1)的底物。最近的研究表明，在所有患者中，MRP1表达和功能的增加与预后更差、CR减少和2年生存率减少(减少65%以上)相关。我们实验室的初步研究表明，BCR/Abl通过酪蛋白激酶2(CK2)调节MRP1功能。CK2受bcr/Abl和Src激酶的调节。有趣的是，用CK2抑制剂和伊马替尼联合治疗所有Ph+细胞已经被证明提高了Gleevec的疗效(IC50下降了35%)(21)。因此，我们假设伊马替尼抑制BCR-Abl下调CK2活性和CK2介导的MRP1功能的诱导，从而导致CVAD化疗药物(BCR-Ab1？CK2？MRP1)的细胞积聚增加。在这项建议中，我们将：1)确定BCR/Ab1诱导MRP1功能的直接机制，2)确定CK2在BCR/Ab1介导的MRP1功能诱导中的作用，以及3)在Ph+ALL组织培养模型系统中验证我们的假设，Sup-B15细胞和直接在患者原代细胞中与Dianna Howard博士合作从肯塔基大学临床获得。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Treatment of high risk acute lymphoblastic leukemia patients whom are positive for the Philadelphia chromosome mutation (ALL Ph+) which results in the fusion of BCR and Abl kinase (BCR/Abl), patients over the years have been extremely difficult. Recently, the standard hyperCVAD (Cyclophosphamide, Vincristine, Dexamethasone, and Doxorubicin) treatment for these patients was modified to include Gleevec (imatinib). The addition of Imatinib has been extremely successful and has increased the complete remission (CR) rate from 60 to 96% and the 2 year survival rate from about 40% of 85%. The mechanism by which Imatinib increases the efficacy of treatment is unclear. Cyclophosphamide metabolites, doxorubicin, and vincristine are all substrates of multidrug resistance protein 1 (MRP1/ABCC1). Recent studies have shown that increased expression and function of MRP1 is associated with a much poorer prognosis, a reduced CR, and a decreased 2 year survival (over 65% reduction) in ALL patients. Preliminary studies carried out in our lab suggest that BCR/Abl regulates MRP1 function via casein kinase 2 (CK2). CK2 is regulated by BCR/Abl and Src kinases. Interestingly, treatment of ALL Ph+ cells with CK2 inhibitors in combination with Imatinib has been shown to increase Gleevec efficacy (a decrease in the IC50 by 35%) (21). Therefore we hypothesize that inhibition of BCR-Abl with Imatinib down regulates CK2 activity and CK2-mediated induction of MRP1 function, this results in increased cellular accumulation of the CVAD chemotherapeutics (BCR-Abl¿CK2¿MRP1). In this proposal we will: 1) Determine the direct mechanism by which BCR/Abl induces MRP1 function, 2) Determine the role of CK2 in BCR/Abl-mediated induction of MRP1 function, and 3) Test our hypothesis in a Ph+ ALL tissue culture model system, Sup-B15 cells and directly in patient primary cells obtained from the University of Kentucky clinic in collaboration with Dr. Dianna Howard.