Yang Jiyuan, Zhang Rui, Radford D Christopher, Kopeček Jindřich
Department of Pharmaceutics and Pharmaceutical Chemistry/CCCD, University of Utah, Salt Lake City, UT 84112, USA.
Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA.
J Control Release. 2015 Nov 28;218:36-44. doi: 10.1016/j.jconrel.2015.09.045. Epub 2015 Sep 26.
To develop a biodegradable polymeric drug delivery system for the treatment of ovarian cancer with the capacity for non-invasive fate monitoring, we designed and synthesized N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-epirubicin (EPI) conjugates. The polymer backbone was labeled with acceptor fluorophore Cy5, while donor fluorophores (Cy3 or EPI) were attached to HPMA copolymer side chains via an enzyme-cleavable GFLG linker. This design allows elucidating separately the fate of the drug and of the polymer backbone using fluorescence resonance energy transfer (FRET). The degradable diblock conjugate (2P-EPI) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization using a bifunctional chain transfer agent (Peptide2CTA). The pharmacokinetics (PK) and therapeutic effect of 2P-EPI (Mw ~100 kDa) were determined in mice bearing human ovarian carcinoma A2780 xenografts. Compared to 1st generation conjugate (P-EPI, Mw <50 kDa), 2P-EPI demonstrated remarkably improved PK such as fourfold terminal half-life (33.22 ± 3.18 h for 2P-EPI vs. 7.55 ± 3.18 h for P-EPI), which is primarily attributed to the increased molecular weight of the polymer carrier. Notably, complete tumor remission and long-term inhibition of tumorigenesis (100 days) were achieved in mice (n=5) treated with 2P-EPI. Moreover, in vitro cell uptake and intracellular drug release were determined via FRET intensity changes. The results establish a solid foundation for future in vivo tracking of drug delivery and chain scission of polymeric conjugates by FRET imaging.
为了开发一种用于治疗卵巢癌的可生物降解聚合物药物递送系统，并具备非侵入性命运监测能力，我们设计并合成了N-(2-羟丙基)甲基丙烯酰胺(HPMA)共聚物-表柔比星(EPI)偶联物。聚合物主链用受体荧光团Cy5标记，而供体荧光团(Cy3或EPI)通过酶可裂解的GFLG接头连接到HPMA共聚物侧链上。这种设计允许使用荧光共振能量转移(FRET)分别阐明药物和聚合物主链的命运。可降解双嵌段偶联物(2P-EPI)通过可逆加成-断裂链转移(RAFT)聚合反应，使用双功能链转移剂(Peptide2CTA)合成。在携带人卵巢癌A2780异种移植瘤的小鼠中测定了2P-EPI(Mw~100 kDa)的药代动力学(PK)和治疗效果。与第一代偶联物(P-EPI，Mw<50 kDa)相比，2P-EPI表现出显著改善的药代动力学，如终末半衰期延长四倍(2P-EPI为33.22±3.18小时，P-EPI为7.55±3.18小时)，这主要归因于聚合物载体分子量的增加。值得注意的是，用2P-EPI治疗的小鼠(n=5)实现了完全肿瘤缓解和肿瘤发生的长期抑制(100天)。此外，通过FRET强度变化测定了体外细胞摄取和细胞内药物释放。这些结果为未来通过FRET成像在体内跟踪药物递送和聚合物偶联物的链断裂奠定了坚实的基础。
