Targeting Leukemic Stem Cells

说明（申请人提供）：尽管近年来我们对涉及血液器官和其它组织的疾病中的基因异常的理解取得了显著的进展，但通过基因治疗方法在靶细胞中引入或操纵基因表达的能力受到限制。尽管已经开发了许多强大的病毒载体并用于实验和人类系统，但许多问题，特别是安全性，已经证明需要开发用于基因治疗的非病毒基载体。最近的发现还表明，靶向正常造血干细胞（HSC）以及白血病干细胞（LSC）是必要的，所述造血干细胞（HSC）是具有自我更新和在给定组织中产生所有细胞类型的潜力的细胞，所述白血病干细胞（LSC）是赋予恶性白血病克隆的自我更新特性的癌细胞亚群。正常人HSC和大多数LSC表达干细胞抗原CD 34，并且该提议将利用该表面标志物的特异性，以及其中鼠HSC表达人CD 34抗原的新型鼠模型。因此，该项目的长期目标是开发针对正常和白血病干细胞的新型非病毒基因治疗方法。为了实现这些目标，我们提出了以下具体目的：（1）在人CD 34细胞系中测试人CD 34抗体介导的siRNA递送;（2）在体内鼠模型中测试人CD 34抗体介导的siRNA;和（3）测试人CD 34抗体介导的BCR/ABL或SALL 4沉默是否将在人CD 34细胞系中产生。 抑制人原代骨髓LSC增殖和白血病引发能力。这些目标的实现将为临床试验奠定基础，并导致针对其他癌基因以及改变干细胞基因表达的疗法的发展。

DESCRIPTION (provided by applicant): Although advances in our understanding of gene abnormalities in diseases involving blood organs and other tissues has been remarkable in recent years, the ability to introduce or manipulate expression of genes in target cells through gene therapy methods has been limited. Although a number of powerful viral vectors have been developed and utilized in both experimental and human systems, a number of issues, particularly safety, have demonstrated the need to develop non-viral based vectors for gene therapy. Recent discoveries have also demonstrated that it is essential to target normal hematopoietic stem cells (HSC), cells which have the potential to both self-renew and to give rise to all cell types in a given tissue, as well as leukemic stem cells (LSC), a subpopulation of cancer cells which confer the self-renewal properties of the malignant leukemic clone. Normal human HSC, and a majority of LSC, express the stem cell antigen CD34, and this proposal will utilize the specificity of this surface marker, as well as a novel murine model in which murine HSC express the human CD34 antigen. Therefore, the long range goals of this project are to develop novel non-viral gene therapy methods targeting normal and leukemic stem cells. In order to accomplish these goals, we propose the following Specific Aims: (1) to test human CD34 antibody mediated siRNA delivery in human CD34 cell lines; (2) to test human CD34 antibody mediated siRNA in murine models in vivo; and (3) to test whether human CD34 antibody mediated silencing of BCR/ABL or SALL4 will inhibit proliferation and leukemia-initiating ability of human primary myeloid LSCs. Accomplishment of these goals will set the stage for clinical trials, as well as lead to development of therapies directed against other oncogenes as well as altering stem cell gene expression.