Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8904, Japan.
Department of Chemistry & Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
Bioconjug Chem. 2021 Aug 18;32(8):1535-1540. doi: 10.1021/acs.bioconjchem.1c00159. Epub 2021 Jul 30.
Photoactivatable ligand proteins are potentially useful for light-induced intracellular delivery of therapeutic and diagnostic cargos through receptor-mediated cellular uptake. Here, we report the simple and effective caging of transferrin (Tf), a representative ligand protein with cellular uptake ability, which has been used in the delivery of various cargos. Tf was modified with several biotin molecules through a photocleavable linker, and then the biotinylated Tf (bTf) was conjugated with the biotin-binding protein, streptavidin (SA), to provide steric hindrance to block the interaction with the Tf receptor. Without exposure to light, the cellular uptake of the bTf-SA complex was effectively inhibited. In response to light exposure, the complex was degraded with the release of Tf, leading to cellular uptake of Tf. Similarly, the cellular uptake of Tf-doxorubicin (Dox) conjugates could be suppressed by caging with biotinylation and SA binding, and the intracellular delivery of Dox could be triggered in a light-dependent manner. The intracellularly accumulated Dox decreased the cell viability to 25% because of the cell growth inhibitory effect of Dox. These results provided proof of principle that the caged Tf can be employed as a photoactivatable molecular device for the intracellular delivery of cargos.
光活化配体蛋白可通过受体介导的细胞摄取，将治疗和诊断有效载荷递送至细胞内，具有潜在的应用价值。本文报告了转铁蛋白（Tf）的简单有效的光笼化，Tf 是一种具有细胞摄取能力的代表性配体蛋白，已被用于各种有效载荷的递送。Tf 通过光裂解连接子与几个生物素分子修饰，然后将生物素化的 Tf（bTf）与生物素结合蛋白链霉亲和素（SA）缀合，提供空间位阻以阻止与 Tf 受体的相互作用。在不暴露于光的情况下，bTf-SA 复合物的细胞摄取被有效抑制。暴露于光后，复合物被降解并释放 Tf，从而导致 Tf 的细胞摄取。类似地，Tf-阿霉素（Dox）缀合物的细胞摄取可以通过生物素化和 SA 结合的笼化来抑制，并且可以以光依赖性的方式触发 Dox 的细胞内递送。细胞内积累的 Dox 降低了细胞活力至 25%，因为 Dox 的细胞生长抑制作用。这些结果证明了光笼化的 Tf 可以作为一种用于细胞内递药的光活化分子装置。
