Targeting eIF2alpha siRNA to alpha(v)beta(3) Integrin-bearing Tumor Cells

描述(申请人提供)：作为细胞死亡的一种方式，细胞凋亡的优势在于它不会引发炎症反应，因此减少了与组织炎症相关的局部和全身有害事件的可能性。真核翻译起始因子eIF2？被选为靶标是因为它在蛋白质合成中很重要，并且是几种翻译调控的中心靶标，涉及因子eIF2的这个蛋白质亚单位的特定磷酸化。抑制蛋白质合成有助于细胞凋亡，这一过程通常是不同病毒诱导细胞凋亡的靶点。在这个拟议的项目中，靶向递送凋亡的eIF2？本研究将以聚阳离子壳聚糖为载体，对携带整合素的肿瘤细胞进行siRNA转导研究。根据已发表的报道，血流中寡核苷酸携带者的循环半衰期缩短，阻止了足够的寡核苷酸到达靶细胞。以减轻eIF2的吞噬作用？对于siRNA载体，我们建议将“自身标记”整合素相关蛋白(CD47)偶联到壳聚糖基siRNA载体上。结合在siRNA纳米载体上的CD47蛋白除了具有抗吞噬功能外，还可以作为靶向整合素高表达的肿瘤细胞的配体。CD47偶联的壳聚糖/siRNA纳米载体在血液循环中的半衰期有望大大延长，从而可以通过整合素更有效地结合部位，并通过eIF2？SiRNA。关于这个项目的教育方面，这个项目的多学科性质将培养出接受过生物医学工程、分子生物学、基因/药物输送和纳米医学培训的学生。除了培养研究生外，该项目的教育计划还将招收几名以生化/生物医学为重点的化工专业本科生，并为他们提供实践有功研究的机会。本科生研究人员将积极参与新技术的开发，探索他们在生物医学领域可能的职业道路。 公共卫生相关性：真核翻译启动因子eIF2？被选为靶点是因为它在蛋白质合成中很重要。由于蛋白质合成的抑制有助于细胞的凋亡，整合素相关蛋白(CD47)结合eIF2？研究表明，siRNA载体可靶向高表达整合素的肿瘤细胞，并可传递凋亡的eIF2？SiRNA。

DESCRIPTION (provided by applicant): As a mode of cell death, apoptosis has an advantage in that it does not invoke an inflammatory response, thus there is decrease possibility of deleterious local and systemic events associated with tissue inflammation. Eukaryotic translation initiation factor eIF2? is chosen as a target because it is important in protein synthesis and is a central target of several types of translational regulation involving specific phosphorylation of this protein subunit of factor eIF2. Inhibition of protein synthesis contributes to cellular apoptosis and this process is often targeted by different viruses for the induction of apoptosis. In this proposed project, targeted delivery of apoptotic eIF2? siRNA to ?v?3 integrin-bearing tumor cells using polycationic chitosan as the vector will be studied. According to published accounts, shortened circulatory half-lives of oligonucleotide carriers in the bloodstream prevent sufficient oligonucleotides from reaching the target cells. To mitigate phagocytosis of eIF2? siRNA carriers, we propose to conjugate the "marker of self" integrin-associated protein (CD47) to chitosan-based siRNA carriers. In addition to its antiphagocytic feature, CD47 protein conjugated on siRNA nanovectors will act as a ligand targeted for tumor cells highly expressed with ?v?3 integrins. The proposed CD47-conjugated chitosan/siRNA nanovectors are expected to have much extended half-lives in blood circulation, hence allowing for more efficient site binding via ?v?3 integrin and eliciting apoptosis of tumor neovasculature by eIF2? siRNA. With regard to educational aspect of this project, the multidisciplinary nature of this project will produce students with training in biomedical engineering, molecular biology, gene/drug delivery, and nanomedicine. In addition to training graduate students, the educational plan of this project will recruit several undergraduates that are Chemical Engineering major with biochemical/biomedical emphasis and provide them with the opportunity of hands-on meritorious research. The undergraduate student researchers will actively participate in the development of new technology and explore their possible career path in biomedical fields. PUBLIC HEALTH RELEVANCE: Eukaryotic translation initiation factor eIF2? is chosen as a target because it is important in protein synthesis. Since inhibition of protein synthesis contributes to cellular apoptosis, integrin-associated protein (CD47) conjugated eIF2? siRNA vectors are proposed to target tumor cells highly expressed with ?v?3 integrins and deliver apoptotic eIF2? siRNA.