以葉酸配體接枝硫酸化軟骨素-聚乙烯亞胺作為腫瘤標靶基因載體之發展

Development of Folic Acid-Modified Chondroitin Sulfate-Polyethylenimine Copolymer for Tumor Targeting Gene Delivery

羅珮綺(Pei-Chi Lo)

指導教授 ： 王麗芳

高雄醫學大學/生命科學院/醫藥暨應用化學研究所/碩士(2013年)

摘要

在先前的研究中，我們已經證實了CS-PEI是個具有潛力的基因載體，但在現今的醫學治療中，針對癌症的基因治療不僅要奠基於好的基因傳遞效率，更要擁有標靶細胞的能力，來提升基因治療的效率。這次的研究延續著之前的研究，利用先前證實具有相當效果的非病毒式基因載體CS-PEI，再修飾上一個葉酸的配體，做為標靶腫瘤基因治療的探討。
依據文獻報導，許多腫瘤細胞的細胞膜上都被證實有葉酸受體的過度表現，而葉酸受體對葉酸有著高度親和力。所以，我們利用這個特點將之前具有良好基因轉染效率的硫酸化軟骨素-聚乙烯亞胺(CS-PEI)，再進一步修飾上葉酸(FA)，合成FAPEG-CP(FPCP)，使載體不僅維持基因轉染的效率並產生標靶治療的效果。而另一方面為了證實葉酸的重要性，我們也合成了甲氧基聚乙二醇-硫酸化軟骨素-聚乙烯亞胺(mPEG-CP, MPCP)共聚物以及葉酸-硫酸化軟骨素-聚乙烯亞胺(FACP)來當做對照組。
在細胞毒性的測試中也顯示出經由改質過後的載體和PEI-25K相比皆有更良好的細胞存活度 。在轉染的部分，經由葉酸改質過的材料FPCP以及FACP皆顯示出比MPCP更佳的螢光表現。而在載體胞噬機制的探討中，也發現接枝上葉酸的材料都會走向Caveolae-mediated endocytosis以及FR-mediated endocytosis，進一步說明了FPCP以及FACP能夠作為有潛力的標靶基因治療載體。

關鍵字

腫瘤 ； 標靶治療 ； 基因載體

並列摘要

In previous study in our group, Chondroitin Sulfate-Polyethylenimine (CS-PEI, CP) was confirmed as a potential gene delivery vector. An efficient gene delivery system is based on not only high transfection efficiency but also the specific targeting ability. In this study, a folate conjugated CS-PEI was synthesized and examined for targeting gene delivery.
Folate receptors (FRs) are overexpressed on cell’s membrane in many types of carcinoma cells. The folate receptors have the high affinity to folic acid (FA), thus, we conjugated FA-linked polyethylene glycol (FA-PEG) onto CP (FPCP) for tumor targeting studies. We also synthesized mPEG-CP without a FA moiety (MPCP) and FA linked-CP without the PEG segment (FACP) for comparison. The in vitro cell tests of polyplexes were done in U87 cells which overexpress folate receptor. The copolymers/DNA-formed polyplexes exhibited less cytotoxicity than did PEI/DNA-formed polyplexes against U87 cells. The transfection efficiency of FPCP/DNA was higher than that of MPCP/DNA.
The cellular uptake mechanisms of these gene carriers were studied. The transfection of FPCP/DNA, MPCP/DNA, and FACP/DNA polyplexes were tested in U87 cells in the presence of different endocytic chemical inhibitors. The results showed that both caveolae-mediated endocytosis and FR-mediated endocytosis were the predominant route of the cellular interlization for these folate-modified copolymers. Thus, the FPCP and FACP copolymers are the potential vectors for gene delivery systems.

並列關鍵字

Tumor ； Targeting delivery ； Gene carrier

參考文獻

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