Materials, Physics, and Molecular, Cellular, & Developmental Biology Departments, University of California at Santa Barbara, Santa Barbara, CA 93106, USA.
Laboratory of Cancer Biology, Institute of Biomedicine and Translational Medicine, Centre of Excellence for Translational Medicine, University of Tartu, Ravila 14b, 50411 Tartu, Estonia.
Biomaterials. 2018 Jun;166:52-63. doi: 10.1016/j.biomaterials.2018.02.052. Epub 2018 Mar 2.
Cationic liposome-nucleic acid (CL-NA) complexes, which form spontaneously, are a highly modular gene delivery system. These complexes can be sterically stabilized via PEGylation [PEG: poly (ethylene glycol)] into nanoparticles (NPs) and targeted to specific tissues and cell types via the conjugation of an affinity ligand. However, there are currently no guidelines on how to effectively navigate the large space of compositional parameters that modulate the specific and nonspecific binding interactions of peptide-targeted NPs with cells. Such guidelines are desirable to accelerate the optimization of formulations with novel peptides. Using PEG-lipids functionalized with a library of prototypical tumor-homing peptides, we varied the peptide density and other parameters (binding motif, peptide charge, CL/DNA charge ratio) to study their effect on the binding and uptake of the corresponding NPs. We used flow cytometry to quantitatively assess binding as well as internalization of NPs by cultured cancer cells. Surprisingly, full peptide coverage resulted in less binding and internalization than intermediate coverage, with the optimum coverage varying between cell lines. In, addition, our data revealed that great care must be taken to prevent nonspecific electrostatic interactions from interfering with the desired specific binding and internalization. Importantly, such considerations must take into account the charge of the peptide ligand as well as the membrane charge density and the CL/DNA charge ratio. To test our guidelines, we evaluated the in vivo tumor selectivity of selected NP formulations in a mouse model of peritoneally disseminated human gastric cancer. Intraperitoneally administered peptide-tagged CL-DNA NPs showed tumor binding, minimal accumulation in healthy control tissues, and preferential penetration of smaller tumor nodules, a highly clinically relevant target known to drive recurrence of the peritoneal cancer.
阳离子脂质体-核酸 (CL-NA) 复合物是一种高度模块化的基因传递系统，可自发形成。通过 PEGylation [PEG：聚乙二醇] 将这些复合物进行空间位阻稳定化，可将其转化为纳米颗粒 (NPs)，并通过亲和配体的连接将其靶向特定组织和细胞类型。然而，目前尚无关于如何有效探索调节肽靶向 NPs 与细胞特异性和非特异性结合相互作用的组成参数的大量空间的指南。这些指南对于加速具有新型肽的制剂的优化是可取的。我们使用用一系列原型肿瘤归巢肽官能化的 PEG-脂质，改变了肽密度和其他参数（结合基序、肽电荷、CL/DNA 电荷比），以研究它们对相应 NPs 结合和摄取的影响。我们使用流式细胞术定量评估了 NPs 与培养的癌细胞的结合和内化。令人惊讶的是，与中间覆盖相比，完全肽覆盖导致更少的结合和内化，最佳覆盖范围在细胞系之间变化。此外，我们的数据表明，必须非常小心，以防止非特异性静电相互作用干扰所需的特异性结合和内化。重要的是，这种考虑因素必须考虑到肽配体的电荷以及膜电荷密度和 CL/DNA 电荷比。为了测试我们的指南，我们在腹膜播散性人类胃癌的小鼠模型中评估了选定 NP 制剂的体内肿瘤选择性。腹腔内给予的肽标记的 CL-DNA NPs 显示出肿瘤结合、在健康对照组织中最小积聚和优先穿透较小的肿瘤结节，这是一个高度临床相关的目标，已知会导致腹膜癌的复发。
