CpG-siRNA Conjugates to Target Acute Myeloid Leukemia

CpG-siRNA 缀合物靶向急性髓系白血病

基本信息

批准号：
8332770
负责人：
Marcin Kortylewski
金额：
$ 34.86万
依托单位：
BECKMAN RESEARCH INSTITUTE/CITY OF HOPE
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-09-15 至 2016-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8332770
关键词：
Acute Myelocytic Leukemia Agonist B-Cell Lymphomas B-Lymphocytes Biochemical Biodistribution Blast Cell Blood Circulation Cell Culture Techniques Cell Death Cell membrane Cells Chemicals Clinical Complex Confocal Microscopy Cytoplasm Disease Drug Kinetics Endosomes Event Gene Combinations Gene Silencing Gene Targeting Genes Growth Half-Life Hematologic Neoplasms Hematopoietic Hematopoietic Neoplasms Human Immune In Vitro Intracellular Transport Lentivirus Vector Life Ligands Link Measures Mediating Modeling Modification Molecular Multiple Myeloma Mus Oligonucleotides Oncogenic Pathway interactions Patients Population Primary Neoplasm RNA Interference RNA Processing Reagent Reporting Resistance STAT5A gene Serum Signal Transduction Small Interfering RNA Specificity TLR9 gene Technology Testing Therapeutic Therapeutic Effect Toxic effect Transfection Translations Transport Process Work base cancer therapy clinical application conventional therapy cytotoxic design immune activation immunotoxicity improved in vitro Assay in vivo innovation interest leukemia macrophage neoplastic cell novel nuclease receptor research study targeted delivery trafficking transcription factor tumor uptake

项目摘要

DESCRIPTION (provided by applicant): Efficient delivery of siRNA to specific cell populations in vivo remains a major challenge to successful therapeutic applications. Hematopoietic cells, including acute myeloid leukemia (AML) cells, pose special problem for siRNA delivery due to low transfection efficiency, which requires the use of lentiviral vectors. We recently demonstrated that ligands for intracellular receptors, such as TLR9, can be used as targeting moieties for cell-specific siRNA delivery. Novel dual-function CpG-siRNA conjugates, generated by synthetically linking siRNA to a CpG oligonucleotide (ODN), target and silence genes specifically in TLR9- positive immune cells including DCs, macrophages and B cells in mice. In contrast to the naked siRNA, the siRNA molecules equipped with a CpG moiety, are rapidly internalized by target cells and localized into endosomes in the absence of any transfection or packaging reagents. Our preliminary studies show that a new CpG-siRNA version, generated by utilizing the CpG sequence optimized for human cell stimulation, allows for gene targeting specifically in human TLR9-positive tumor cells, such as AML. We demonstrated that local as well as systemic administration of CpG-siRNAs targeting oncogenic and/or pro-survival genes induced tumor cell death and inhibited growth of xenotransplanted human AML tumors. To optimize CpG- siRNA strategy for use in anticancer therapy, we propose to define the molecular mechanisms and intracellular events involved in TLR9-mediated gene silencing. We also need to prolong stability and circulation half-life of CpG-siRNA reagents to maximize their efficacy for systemic administration. The nuclease-resistant and long-lived conjugates will be generated through chemical modifications and multimerization of CpG-siRNAs. Next, we plan to use the CpG-siRNA strategy to target STAT5, a transcription factor mediating survival of the vast majority of AML tumors. We will assess the effect of optimized CpG-STAT5 siRNA against disseminated AML tumor models and primary leukemic blasts from leukemia patients. Additionally, we will test the effect of CpG-STAT5 siRNA on viability and immune activation of normal human immune cells. Results from the proposed studies have potential to overcome major hurdles limiting the application of siRNA therapeutics, allowing for silencing of currently non- druggable target genes, like STAT5, thereby blocking AML proliferation and survival. We anticipate that with better understanding of the mechanism(s) underlying TLR9-mediated silencing effect and with CpG-siRNA conjugates optimized for use against disseminated tumors, the proposed studies will produce a technology platform applicable to broad clinical application against AML and other hematologic malignancies. In a long- term perspective, this work has potential to generate novel, more effective and safer therapeutics, expanding treatment options for the benefit of patients with various forms of blood cancers.

描述（由申请人提供）：将 siRNA 有效递送至体内特定细胞群仍然是成功治疗应用的主要挑战。造血细胞，包括急性髓系白血病 (AML) 细胞，由于转染效率低，给 siRNA 递送带来了特殊问题，需要使用慢病毒载体。我们最近证明，细胞内受体的配体（例如 TLR9）可以用作细胞特异性 siRNA 递送的靶向部分。新型双功能 CpG-siRNA 缀合物是通过将 siRNA 合成连接到 CpG 寡核苷酸 (ODN) 生成的，可特异性靶向和沉默 TLR9 阳性免疫细胞（包括小鼠 DC、巨噬细胞和 B 细胞）中的基因。与裸露的siRNA相比，配备有CpG部分的siRNA分子在没有任何转染或包装试剂的情况下被靶细胞快速内化并定位到核内体中。我们的初步研究表明，利用针对人类细胞刺激优化的 CpG 序列生成的新 CpG-siRNA 版本，可以在人类 TLR9 阳性肿瘤细胞（例如 AML）中进行基因靶向。我们证明，针对致癌和/或促生存基因的 CpG-siRNA 的局部和全身给药可诱导肿瘤细胞死亡并抑制异种移植的人类 AML 肿瘤的生长。为了优化用于抗癌治疗的 CpG-siRNA 策略，我们建议定义 TLR9 介导的基因沉默涉及的分子机制和细胞内事件。我们还需要延长 CpG-siRNA 试剂的稳定性和循环半衰期，以最大限度地提高其全身给药的功效。抗核酸酶且寿命长的缀合物将通过 CpG-siRNA 的化学修饰和多聚化产生。接下来，我们计划使用 CpG-siRNA 策略来靶向 STAT5，这是一种介导绝大多数 AML 肿瘤存活的转录因子。我们将评估优化的 CpG-STAT5 siRNA 对播散性 AML 肿瘤模型和白血病患者原发性白血病母细胞的效果。此外，我们将测试 CpG-STAT5 siRNA 对正常人体免疫细胞的活力和免疫激活的影响。拟议研究的结果有可能克服限制 siRNA 疗法应用的主要障碍，允许沉默目前不可药物化的靶基因，如 STAT5，从而阻止 AML 增殖和存活。我们预计，通过更好地了解 TLR9 介导的沉默作用的机制以及针对播散性肿瘤进行优化的 CpG-siRNA 缀合物，拟议的研究将产生一个适用于针对 AML 和其他血液恶性肿瘤的广泛临床应用的技术平台。从长远来看，这项工作有可能产生新颖、更有效和更安全的治疗方法，扩大治疗选择，造福各种形式的血癌患者。