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Ligand Density and Nanoparticle Clustering Cooperate in the Multivalent Amplification of Epidermal Growth Factor Receptor Activation
ACS Nano ( IF 15.8 ) Pub Date : 2018-10-05 00:00:00 , DOI: 10.1021/acsnano.8b06141
Qianyun Zhang 1 , Björn M Reinhard 1
Affiliation  

Multivalent presentation of ligands on nanoparticles (NPs) is considered a general strategy for enhancing receptor binding and activation through amplification of ligand–receptor interactions within the footprint of the individual NPs. The spatial clustering of ligand-functionalized NPs represents an additional, less well understood mechanism for increasing local ligand–receptor interactions, especially for receptors that form higher-order assemblies, such as the epidermal growth factor (EGF) receptor (EGFR). To shed light on the interplay between ligand density (i.e., multivalency) and NP clustering in signal amplification, we apply EGF-functionalized 72 ± 1 nm gold nanoparticles (NP-EGF) with known ligand loading (10–200 EGF/NP) as quantifiable and experimentally tractable units of EGFR activation and characterize the NP-mediated amplification of EGFR phosphorylation as a function of both EGF surface density and NP-EGF clustering for two cancer cell lines (HeLa and MDA-MB-468). The measurements confirm a strong multivalent amplification of EGFR phosphorylation through NP-EGF on the cellular level that results in EGF-loading-dependent maximum EGFR phosphorylation levels. A microscopic analysis of NP-EGF-induced EGFR phosphorylation reveals a heterogeneous spatial distribution of EGFR activation across the cell surface. Clustering of multivalent NP-EGF on sub-diffraction-limited length scales is found to result in a local enhancement of EGFR phosphorylation in signaling “hot spots” from where the signal can spread laterally in an EGF-independent fashion. Increasing EGF loadings of the NP enhances NP-EGF clustering and intensifies EGFR phosphorylation. These observations suggest that NP-EGF clustering and the associated local enhancement of ligand–receptor interactions are intrinsic components of the multivalent amplification of phosphorylation for the heterogeneously distributed EGFR through NP-EGF.

中文翻译:


配体密度和纳米颗粒簇协同作用于表皮生长因子受体激活的多价扩增



纳米颗粒(NP)上配体的多价呈现被认为是通过放大单个纳米颗粒足迹内的配体-受体相互作用来增强受体结合和激活的一般策略。配体功能化纳米粒子的空间聚集代表了一种额外的、不太为人所知的机制,用于增加局部配体-受体相互作用,特别是对于形成更高阶组装体的受体,例如表皮生长因子(EGF)受体(EGFR)。为了阐明信号放大中配体密度(多价)和 NP 聚类之间的相互作用,我们应用具有已知配体负载(10-200 EGF/NP)的 EGF 功能化 72 ± 1 nm 金纳米粒子(NP-EGF)作为EGFR 激活的可量化和实验可处理的单位,并将 NP 介导的 EGFR 磷酸化放大表征为两种癌细胞系(HeLa 和 MDA-MB-468)的 EGF 表面密度和 NP-EGF 聚类的函数。测量证实了 NP-EGF 在细胞水平上对 EGFR 磷酸化的强烈多价放大,导致 EGF 负载依赖性最大 EGFR 磷酸化水平。对 NP-EGF 诱导的 EGFR 磷酸化的显微镜分析揭示了 EGFR 激活在整个细胞表面的异质空间分布。研究发现,多价 NP-EGF 在亚衍射极限长度尺度上的聚集会导致信号“热点”中 EGFR 磷酸化的局部增强,信号可以从该热点以不依赖于 EGF 的方式横向传播。增加 NP 的 EGF 负载量可增强 NP-EGF 聚集并强化 EGFR 磷酸化。 这些观察结果表明,NP-EGF 聚类和配体-受体相互作用的相关局部增强是通过 NP-EGF 异质分布的 EGFR 磷酸化多价放大的内在组成部分。
更新日期:2018-10-05
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