Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, School of Pharmaceutical Sciences, State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100191, China.
Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA.
J Control Release. 2018 Apr 10;275:129-141. doi: 10.1016/j.jconrel.2018.01.033. Epub 2018 Feb 2.
The peptide-drug conjugates caused much attention currently. The purpose of present study was to elucidate the possible synergistic effect between ligand peptide and stimuli-responsive linkage in amphiphilic peptide-drug conjugates (APDCs) with different linkers. Especially, the superiority of each strategy as well as the synergistic effect between them was carefully investigated via the parallel comparisons of the three systems throughout of the whole study. Here, we synthesized three APDCs, namely, cRGD-SS-DOX (RSSDOX), cRGD-S-DOX (RSDOX) and cRGD-VC-DOX (RVCDOX), using doxorubicin (DOX) as a model cytotoxic agent, cRGDfC as a homing peptide, and reduction cleavable disulfide (SS), noncleavable single thioether (S) or cathepsin B cleavable valine-citrulline dipeptide (VC) as linker. The APDCs showed high drug loading capacity and they were evaluated in vitro in the integrin αvβ3-overexpressing B16 cells and in vivo in tumor-bearing C57BL/6 mice. Endocytosis mechanism assay demonstrated that three types of APDCs internalized into cells through adynamin and actin depolymerizing-mediated pathway following receptor-mediated endocytosis. Notably, RSDOX or RVCDOX induced stronger antitumor efficacy, which depended on their cellular uptake levels, intracellular trafficking and the colocalization rates with lysosomes. The in vivo efficacy of RSDOX or RVCDOX was 1.4-1.7 fold of free DOX and 1.7-2.0 fold of RSSDOX, respectively. In addition, RSDOX or RVCDOX demonstrated acceptable system, tissue and blood compatibility. The compromised efficacy of RSSDOX might be due to the generation of DOX-SH during degradation of prodrug, but not DOX. Taken together, our studies suggest that certain type of APDCs can significantly decrease the toxicity of free DOX and improve therapy outcome, which provides insight for the design of peptide-drug conjugates integrating ligand peptide and stimuli-responsive linkage.
肽药物偶联物目前受到了广泛关注。本研究旨在阐明不同连接子的两亲性肽药物偶联物（APDC）中配体肽和刺激响应性连接之间可能存在的协同作用。特别是，通过在整个研究过程中对三个系统的平行比较，仔细研究了每种策略的优势以及它们之间的协同作用。在这里，我们合成了三种 APDC，即 cRGD-SS-DOX（RSSDOX）、cRGD-S-DOX（RSDOX）和 cRGD-VC-DOX（RVCDOX），以阿霉素（DOX）为模型细胞毒性药物，cRGDfC 为同源肽，以及还原裂解二硫键（SS）、非裂解单硫醚（S）或组织蛋白酶 B 裂解缬氨酸-瓜氨酸二肽（VC）作为连接子。APDC 具有高载药能力，并在整合素 αvβ3 过表达的 B16 细胞中和荷瘤 C57BL/6 小鼠中进行了体外评估。内吞作用机制研究表明，三种 APDC 通过网格蛋白和肌动蛋白解聚介导的途径，通过受体介导的内吞作用进入细胞。值得注意的是，RSDOX 或 RVCDOX 诱导更强的抗肿瘤疗效，这取决于它们的细胞摄取水平、细胞内转运和与溶酶体的共定位率。RSDOX 或 RVCDOX 的体内疗效分别是游离 DOX 的 1.4-1.7 倍和 RSSDOX 的 1.7-2.0 倍。此外，RSDOX 或 RVCDOX 表现出可接受的系统、组织和血液相容性。RSSDOX 疗效降低可能是由于前药降解过程中生成了 DOX-SH，而不是 DOX。总之，我们的研究表明，某些类型的 APDC 可以显著降低游离 DOX 的毒性并改善治疗效果，这为设计整合配体肽和刺激响应性连接的肽药物偶联物提供了新的思路。
