Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455, USA.
J Control Release. 2017 Apr 10;251:24-36. doi: 10.1016/j.jconrel.2017.02.017. Epub 2017 Feb 17.
Nanoparticles functionalized with cancer-targeting ligands have shown promise but are still limited by off-tumor binding to healthy tissues that express low levels of the molecular target. Targeting two cancer biomarkers using dual-targeted heteromultivalent nanoparticles presents a possible solution to this challenge by requiring overexpression of two separate ligands for localization. In order to guide experimental design, a kinetic model was built to explore how the affinity and valency of dual-ligand liposomes affect the binding and selectivity of delivery to cells with various receptor expression. αβ and αβ integrin expression levels were quantified on 20 different cell lines to identify appropriate model cells for in vitro investigation. Dual-targeting heteromultivalent liposomes covered with polyethylene glycol (PEG) were synthesized using the PR_b peptide that binds to the αβ integrin and the AG86 peptide that binds to the αβ integrin. PEGylated liposomes with varying ratios of the targeting peptides were delivered to cells with different integrin concentrations. Nanoparticle binding and internalization as well as integrin internalization as a function of time were evaluated to understand the effect of valency and avidity on delivery. Results showed that of all formulations and cells tested, dual-ligand liposomes with equal ligand valencies achieved enhanced binding and selectivity for cancer cells expressing equal and high levels of receptor expression. These trends were consistent between theoretical and experimental results. The optimized liposomes were further used to achieve efficient and selective transfection in dual-receptor expressing cancer cells. With a quantitative understanding of dual-ligand liposome binding, the insights gained from this study can inform rational design of modular heteromultivalent nanoparticles for enhanced specificity to target tissue for the creation of more effective cancer treatments.
用癌症靶向配体功能化的纳米颗粒已经显示出了前景，但仍受到肿瘤外与健康组织结合的限制，而这些健康组织低表达分子靶标。使用双靶向杂化多价纳米颗粒靶向两种癌症生物标志物可能是解决这一挑战的一种方法，因为需要两种独立的配体过表达才能进行定位。为了指导实验设计，构建了一个动力学模型来探索双配体脂质体的亲和力和价态如何影响具有不同受体表达的细胞的结合和选择性递药。在 20 种不同的细胞系中定量测定了αβ和αβ整合素的表达水平，以确定适合体外研究的模型细胞。使用与 αβ整合素结合的 PR_b 肽和与 αβ整合素结合的 AG86 肽合成了覆盖有聚乙二醇 (PEG) 的双靶向杂化多价脂质体。用不同比例靶向肽的 PEG 化脂质体递送到具有不同整合素浓度的细胞。评估了纳米颗粒结合和内化以及整合素内化随时间的变化，以了解价态和亲合力对递药的影响。结果表明，在所测试的所有制剂和细胞中，具有相等配体价态的双配体脂质体对表达相等和高水平受体表达的癌细胞具有增强的结合和选择性。这些趋势在理论和实验结果之间是一致的。优化后的脂质体进一步用于在双受体表达的癌细胞中实现高效和选择性转染。通过对双配体脂质体结合的定量理解，本研究获得的见解可以为增强对靶向组织的特异性的模块化杂化多价纳米颗粒的合理设计提供信息，从而为创建更有效的癌症治疗方法创造更多的可能性。
