Department of Pharmacy , Birla Institute of Technology & Science-Pilani, Hyderabad Campus , Medchal , Hyderabad, Telangana 500078 , India.
Mol Pharm. 2019 Apr 1;16(4):1541-1554. doi: 10.1021/acs.molpharmaceut.8b01232. Epub 2019 Mar 12.
This study involves development of a dendrimer-based nanoconstruct by conjugating α-tocopheryl succinate (α-TOS) and polyethylene glycol (PEG) on a poly(amidoamine) dendrimer (G4 PAMAM) to improve intracellular delivery of a poorly water-soluble chemotherapeutic drug, paclitaxel (PTX). The conjugates were characterized by NMR, and PTX-loaded nanocarriers (G4-TOS-PEG-PTX) were evaluated for hydrodynamic diameter, polydispersity index (PDI), zeta potential, percentage encapsulation efficiency (%EE), and percentage drug loading (%DL). A hemolysis study was performed, which indicated that the synthesized dendrimer conjugates were not toxic to red blood cells; hence, they were biocompatible. A cellular uptake study in (B16F10 and MDA MB231) monolayer cells and 3D spheroids showed that α-TOS conjugation improved the time dependent uptake of nanosized dendrimer conjugates. The cell viability assay revealed that G4-TOS-PEG-PTX enhanced the cytotoxicity of PTX as compared to free PTX and PTX-loaded G4-PEG (G4-PEG-PTX) at tested concentrations. Correspondingly, the α-TOS-anchored dendrimer induced more apoptosis as compared to free PTX and G4-PEG-PTX. Moreover, the fluorescently labeled G4-TOS-PEG penetrated deeper into MDA MB231 3D spheroids as visualized by confocal microscopy. G4-TOS-PEG-PTX showed significant growth inhibition in 3D spheroids as compared to free PTX and G4-PEG-PTX. Further, the in vivo efficacy study using B16F10 xenografted C57Bl6/J mice indicated that the G4-TOS-PEG localized in tumor sections. G4-TOS-PEG-PTX reduced the tumor growth significantly compared to free PTX and G4-PEG-PTX. G4-TOS-PEG-PTX had more apoptotic potential in tumor sections as analyzed by TUNEL assay. Hence, the newly developed dendrimer conjugate, G4-TOS-PEG, has the potential to target loaded drug to the tumor, and G4-TOS-PEG-PTX has the potential to be utilized successfully in cancer treatment.
本研究通过将 α-生育酚琥珀酸酯（α-TOS）和聚乙二醇（PEG）偶联到聚（酰胺-胺）树枝状大分子（G4 PAMAM）上来构建基于树枝状大分子的纳米结构，以提高疏水性化疗药物紫杉醇（PTX）的细胞内递送。通过 NMR 对缀合物进行了表征，并评估了载紫杉醇的纳米载体（G4-TOS-PEG-PTX）的水动力直径、多分散指数（PDI）、zeta 电位、包封效率（%EE）和载药量（%DL）。进行了溶血研究，表明合成的树枝状大分子缀合物对红细胞没有毒性，因此具有生物相容性。在（B16F10 和 MDA MB231）单层细胞和 3D 球体中的细胞摄取研究表明，α-TOS 缀合改善了纳米尺寸树枝状大分子缀合物的时间依赖性摄取。细胞活力测定表明，与游离 PTX 和载 PTX 的 G4-PEG（G4-PEG-PTX）相比，G4-TOS-PEG-PTX 增强了 PTX 的细胞毒性，在测试浓度下。相应地，与游离 PTX 和 G4-PEG-PTX 相比，α-TOS 锚定的树枝状大分子诱导更多的细胞凋亡。此外，通过共聚焦显微镜观察，荧光标记的 G4-TOS-PEG 更深地渗透到 MDA MB231 3D 球体中。与游离 PTX 和 G4-PEG-PTX 相比，G4-TOS-PEG-PTX 在 3D 球体中表现出明显的生长抑制作用。此外，使用 B16F10 异种移植 C57Bl6/J 小鼠的体内功效研究表明，G4-TOS-PEG 定位于肿瘤切片中。与游离 PTX 和 G4-PEG-PTX 相比，G4-TOS-PEG-PTX 显著降低了肿瘤生长。通过 TUNEL 分析，G4-TOS-PEG-PTX 在肿瘤切片中具有更大的凋亡潜力。因此，新开发的树枝状大分子缀合物 G4-TOS-PEG 具有将负载药物靶向肿瘤的潜力，并且 G4-TOS-PEG-PTX 有可能成功用于癌症治疗。
