靶向BST2微泡造影剂的制备及其与肿瘤细胞的体外结合能力

目的 制备骨髓基质抗原蛋白(BST2)靶向微泡造影剂,观察其与小鼠前列腺癌细胞(RM-1)和小鼠乳腺癌细胞(4T1)的体外结合能力,探讨BST2作为前列腺癌潜在靶点的可行性.方法 通过免疫荧光染色和蛋白质印迹法对BST2在两种细胞中的表达进行对比分析.采用生物素-亲和素桥连技术制备BST2靶向脂质微泡,普通光镜下观察BST2靶向微泡造影剂,并采用Accu Sizer 780A粒度仪进行表征,以非靶向微泡作为对照,比较其与RM-1和4T1两种肿瘤细胞系的结合特性及结合率.结果 BST2在RM-1细胞中的表达高于在4T1细胞中的表达;BST2靶向微泡与RM-1细胞的黏附率明显高于其与4T1细胞的黏附率,并远远高于非靶向微泡的黏附率.结论 BST2靶向微泡造影剂可与RM-1细胞特异性结合,有望作为前列腺癌的特异性超声分子探针用于前列腺癌的靶向分子成像.

Preparation of BST2 targeted ultrasound contrast agent and its in vitro binding with tumor cells

Objective To investigate the feasibility of bone marrow stromal antigen 2 (BST2) as a potential target for prostate cancer by preparation of BST2 targeted microbubbles as ultrasound contrast agent and evaluation on the in vitro targeting ability with mouse prostate tumor cells (RM-1) and breast cancer cells (4T1). Methods By immunofluorescence staining and Western blotting assays, the expression level of BST2 protein was analyzed and compared in both RM-1 and 4T1 cells. The biotinylated anti-BST2 monoclonal antibody was used to prepare targeted microbubbles through the biotin-avidin bridge. The resulting BST2-targeted microbubbles were observed under light microscope and characterized by AccuSizer 780A particle size analyzer. The targeting specificity and attachment capability of the BST2 targeted microbubbles to RM-1 and 4T1 cells were assessed in vitro. Results Expression of BST2 protein in RM-1 cells was significantly higher than in 4T1 cells. BST2 targeted microbubbles attached with tumor cells obviously compared with non-targeted microbubbles. RM-1 cells possessed significantly higher attachment capability than that with 4T1 cells in vitro. Conclusion BST2 targeted microbubbles are successful prepared, which are able to specifically adhere to RM-1 cells, therefore serving as a potential valuable targeted probe for ultrasound molecular imaging of prostate cancer.