Department of Materials Science and Engineering, University of Michigan, 2300 Hayward St., Ann Arbor, MI, 48109, USA.
Department of Biomedical Engineering, University of Michigan, 1101 Beal Avenue, Ann Arbor, MI, 48109, USA.
Adv Healthc Mater. 2017 Mar;6(5). doi: 10.1002/adhm.201601046. Epub 2017 Jan 13.
This study describes the development of targeted, doxorubicin (DOX)-loaded generation 5 (G5) polyamidoamine dendrimers able to achieve cell-specific DOX delivery and release into the cytoplasm of hepatic cancer cells. G5 is functionalized with poly(ethylene glycol) (PEG) brushes displaying N-acetylgalactosamine (NAcGal) ligands to target hepatic cancer cells. DOX is attached to G5 through one of two aromatic azo-linkages, L3 or L4, achieving either P1 ((NAcGal -PEGc) -G5-(L3-DOX) ) or P2 ((NAcGal -PEGc) -G5-(L4-DOX) ) conjugates. After confirming the conjugates' biocompatibility, flow cytometry studies show P1/P2 achieve 100% uptake into hepatic cancer cells at 30-60 × 10 m particle concentration. This internalization correlates with cytotoxicity against HepG2 cells with 50% inhibitory concentration (IC ) values of 24.8, 1414.0, and 237.8 × 10 m for free DOX, P1, and P2, respectively. Differences in cytotoxicity prompted metabolomics analysis to identify the intracellular release behavior of DOX. Results show that P1/P2 release alternative DOX metabolites than free DOX. Stable isotope tracer studies show that the different metabolites induce different effects on metabolic cycles. Namely, free DOX reduces glycolysis and increases fatty acid oxidation, while P1/P2 increase glycolysis, likely as a response to high oxidative stress. Overall, P1/P2 conjugates offer a platform drug delivery technology for improving hepatic cancer therapy.
本研究描述了靶向、阿霉素（DOX）负载的第五代（G5）聚酰胺胺树枝状大分子的开发，该大分子能够实现肝癌细胞的特异性 DOX 递药和细胞质内释放。G5 通过聚乙二醇（PEG）刷功能化，显示 N-乙酰半乳糖胺（NAcGal）配体，以靶向肝癌细胞。DOX 通过两种芳香偶氮键之一 L3 或 L4 连接到 G5 上，分别实现 P1（（NAcGal-PEGc）-G5-（L3-DOX））或 P2（（NAcGal-PEGc）-G5-（L4-DOX））缀合物。在确认缀合物的生物相容性后，流式细胞术研究表明，P1/P2 在 30-60×10 m 颗粒浓度下可实现 100%摄取进入肝癌细胞。这种内化与对 HepG2 细胞的细胞毒性相关，游离 DOX、P1 和 P2 的 50%抑制浓度（IC ）值分别为 24.8、1414.0 和 237.8×10 m。细胞毒性的差异促使代谢组学分析以确定 DOX 的细胞内释放行为。结果表明，P1/P2 释放替代 DOX 代谢物，而不是游离 DOX。稳定同位素示踪研究表明，不同的代谢物对代谢循环产生不同的影响。即，游离 DOX 降低糖酵解并增加脂肪酸氧化，而 P1/P2 增加糖酵解，可能是对高氧化应激的反应。总的来说，P1/P2 缀合物为改善肝癌治疗提供了一种平台药物递送技术。
