重组人内皮抑素PEG-PE胶束的制备及抑瘤效应研究

Preparation of encapsulation of recombinant human endostatin in PEG-PE micelles and inhibition effects on tumor cells growth and neovascularization of CAM

目的:内皮抑素是强效的血管内皮细胞生长抑制剂,但其低溶解度限制了临床应用,通过采用聚乙二醇衍生化磷脂酰乙醇胺(PEG-PE)制备包载重组人内皮抑素的胶束,以期寻找内皮抑素的新药物载体。方法:研究PEG-PE内皮抑素胶束的理化性质,观察PEG-PE内皮抑素胶束对体外肿瘤细胞生长的作用及对鸡胚绒毛尿囊体内血管生长的影响。结果:制备的PEG-PE-内皮抑素胶束的粒径为(48.32±8.29)nm,Zeta电位为+3.2 mV。包封率为75%,该胶束可以抑制MCF-7肿瘤细胞的生长和增殖,内皮抑素浓度50μg.mL-1时抑制率为31.4%,对鸡胚绒毛尿囊血管新生也有明显的抑制作用。结论:同单独用内皮抑素比较,用PEG-PE胶束作为药物载体运送内皮抑素直接抑制肿瘤细胞生长和抑制新生血管形成的效果更明显。

Objective： Recombinant human endostatin （rhEndostatin） have been shown to inhibit vascular endothelial proliferation. However, low solubility of rhEndostatin limits its therapeutic potential. In order to obtain an effective delivery system pemitting transported rhEndostatin into tumor cell, phospholipid micelles made of polyethyleneglycol phosphatidyl ethanolamine （PEG-PE） was studied. Methods： The size and morphology of micelles encapsulating rhEndostatin were examined using dynamic light scattering （DLS） and transmission electron microscopy （TEM）. The entrapment efficiency in micelles was investigated by the high speed centrifugation method. The corresponding in vitro antitumor effect of encapsulation of rhEndostatin in PEG-PE micelles was obtained on MCF-7 cells from 3-（4, 5- dimethylthiazol-2-yl ） -2,5-diphenyhetrazolium bromide （MTF） assay. The inhibition of neovascularization was studied by chicken embryo chorioallantoic membrane （CAM）. Results： The mean diameter of the rhEndostatin -encapsulated micelles was 48. 32 nm with narrow size distribution. Encapsulation efficiency in micelles was 75%. The micellar rhEndostatin exhibited an irregular spherical shape from TEM photographs. Encapsulation of this micelles was demonstrated significant antitumor activity on MCF-7 cell proliferation, with an inhibition rate of 31.4% when the concentration of rhEndostatin was at 50 μg·mL^-1. And neovascularization in CAM was inhibited efficiently compared to the rhEndostatin alone. Gonclusion： Encapsulation of rhEndostatin in PEG-PE micelles are effective compound in inhibiting tumor cell growth and vascular endothelial prolification compared to rhEndostatin.