Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011-2230, United States.
Int J Pharm. 2012 May 1;427(1):88-96. doi: 10.1016/j.ijpharm.2011.10.018. Epub 2011 Oct 13.
A temperature-responsive pentablock copolymer (PB) was designed to deliver DNA and provide prolonged gene expression by forming a thermogelling release depot after subcutaneous or intratumoral injection. A synthetic barrier gel was developed based on poly(ethylene glycol) diacrylate to enable the released vectors to instantly and continuously transfect cultured cells. The aim of this setup was to provide a simple and controlled in vitro system to mimic tumor matrix to optimize the release system and to study the influence of the continuous and sustained release of the polyplexes on the in vitro transfection. The porosity of the barrier gel was adjusted by addition and removal of Pluronic F127 (PL), and the properties of the gel were characterized by visual inspection and scanning electron microscopy (SEM). Concentrated PB-based vector was administered to the barrier gel and allowed to be released to the buffer. We found that most of feed vector could be released from the barrier gel without unpacking the polymer-DNA complexes. Based on the specific construction of the PB-based vectors, an anti-cancer drug paclitaxel (PTX) was further loaded into the same vector designed for DNA delivery, thus formulating a gene and drug co-delivery system. This system was tested for sustained delivery to human ovarian carcinoma cells SKOV3 using the barrier gel in vitro as a tumor mimic. Transfection efficiency was found to be significantly enhanced by co-delivering PTX, while PTX also showed its effect as an anti-cancer drug to induce cell death. Yet both of the two effects of PTX shown in SKOV3 cells turned out to be dramatically weaker in ARPE-19 cells, a human non-cancerous cell line, which might be related to the nature of the vector itself. Instant release of vectors showed the ability to maintain transfection up to the fourth day, making the gene expression stable at least for the first 5 days. Further study is still needed to improve the duration of effective release.
设计了一种温度响应性五嵌段共聚物 (PB)，通过在皮下或肿瘤内注射后形成热凝胶释放库来递送 DNA 并提供延长的基因表达。基于聚乙二醇二丙烯酸酯开发了一种合成屏障凝胶，以使释放的载体能够立即并持续转染培养细胞。该设置的目的是提供一个简单且受控的体外系统来模拟肿瘤基质，以优化释放系统并研究多聚物的连续和持续释放对体外转染的影响。通过添加和去除 Pluronic F127 (PL) 来调整屏障凝胶的孔隙率，并通过目视检查和扫描电子显微镜 (SEM) 来表征凝胶的性质。将浓缩的基于 PB 的载体施用于屏障凝胶并允许其释放到缓冲液中。我们发现大多数饲料载体可以从屏障凝胶中释放出来，而无需拆开聚合物-DNA 复合物。基于 PB 基载体的特定结构，进一步将抗癌药物紫杉醇 (PTX) 加载到用于 DNA 传递的相同载体中，从而形成基因和药物共传递系统。该系统使用体外屏障凝胶作为肿瘤模拟物，用于持续递送至人卵巢癌细胞 SKOV3。发现共递送 PTX 可显著提高转染效率，而 PTX 也表现出其作为抗癌药物诱导细胞死亡的作用。然而，在 SKOV3 细胞中，PTX 的这两种作用的效果都明显弱于人非癌细胞系 ARPE-19 细胞，这可能与载体本身的性质有关。载体的即时释放显示出能够维持转染至少 4 天的能力，从而使基因表达至少在第 5 天保持稳定。仍需要进一步研究以提高有效释放的持续时间。
