Relevance of folic acid/polymer ratio in targeted PEG-epirubicin conjugates
Relevance of folic acid/polymer ratio in targeted PEG-epirubicin conjugates
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DOI：
10.1016/j.jconrel.2010.05.027
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发表时间：
2010-09-15
影响因子：
10.8
通讯作者：
Schiavon, Oddone
中科院分区：
文献类型：
--
作者：
Canal, Fabiana;Vicent, Maria J.;Schiavon, Oddone
合成了一系列具有不同叶酸含量的PEG-表阿霉素缀合物，以研究聚合物/靶向部分比例对选择性细胞毒性、细胞摄取和细胞内定位的影响。研究了不含叶酸的类似羧基封端的缀合物作为对照。异双官能HO-PEG-COOH被用作聚合物载体，允许缀合物的合成具有对化学结构和药物/聚合物以及聚合物/靶向残基比率的良好控制。在PEG链的一端合成树枝状结构，目的是增加叶酸分子的数量。L-2-氨基己二酸用作支化单元。该偶联物在几种生理条件下显示出高稳定性。在A549、HeLa和KB-3-1人细胞系中进行生物学评价，因为这些细胞具有不同水平的叶酸受体（FR）表达。特别地，A549细胞是FR阴性（FR-），HeLa细胞是FR阳性（FR+），KB-3-1细胞过表达FR（FR++）。清楚地表明，缀合物的生物活性受到每个聚合物链上叶酸分子的存在和数量以及细胞表面上FR表达水平的影响。还研究了溶液中的缀合物构象，因为大小的差异可能会很好地影响细胞内化。在细胞活力测定中，不含叶酸的缀合物出乎意料地比靶向缀合物更具细胞毒性，但它们的IC 50值在三种细胞系中相似。因此，从FR（-）到FR（++）细胞，靶向衍生物的抗增殖活性显著增加。流式细胞仪和共聚焦显微镜研究显示，与其非靶向类似物相比，靶向缀合物的细胞内化更大：更重要的是，这种关系显然取决于缀合物中的叶酸含量和所用细胞系中的FR表达水平。(c)2010爱思唯尔有限公司版权所有。
A Series of PEG-epirubicin conjugates with different folic acid contents per polymer chain was synthesized in order to study the influence of polymer/targeting moiety ratio on selective cytotoxicity, cellular uptake and intracellular localization. Analogous carboxyl-terminated conjugates without folic acid were studied as control. The heterobifunctional HO-PEG-COOH was used as polymeric carrier, allowing the synthesis of conjugates with a good control over the chemical structure and the drug/polymer and polymer/targeting residue ratios. A dendron structure was synthesized at one end of the PEG chain with the aim to increase the number of folic acid molecules. L-2-aminoadipic acid was used as branching unit. The conjugates showed high stability under several physiological conditions. Biological evaluation was carried out in A549, HeLa and KB-3-1 human cell lines, as these cells have different levels of folate receptor (FR) expression. In particular A549 cells are FR negative (FR-), HeLa cells are FR positive (FR+) and KB-3-1 cells over-express FR (FR++). It was clearly shown that the biological activity of the conjugates was influenced by the presence and the number of folic acid molecules per polymer chain and by the level of FR expression on cell surface. Conjugates conformation in solution was also studied, as differences in size might well affect cell internalization. In the cell viability assay, conjugates without folic acid were unexpectedly more cytotoxic than the targeted conjugates, but their IC50 values were similar in the three cell lines. Differently, the anti-proliferative activity of targeted derivatives markedly increased going from FR(-) to FR(++) cells. FACS and confocal microscopy studies showed greater cellular internalization with the targeted conjugates than with their non-targeted analogues: more importantly, this relationship is clearly dependent on folic acid content in the conjugates and FR expression level in the cell line used. (c) 2010 Elsevier B.V. All rights reserved.