Begley D J, Lechardeur D, Chen Z D, Rollinson C, Bardoul M, Roux F, Scherman D, Abbott N J
Biomedical Sciences Division, King's College London, England.
J Neurochem. 1996 Sep;67(3):988-95. doi: 10.1046/j.1471-4159.1996.67030988.x.
The presence of P-glycoprotein in the cell plasma membrane limits the penetration of many cytotoxic substances into cells that express the gene product. There is considerable evidence also to indicate that P-glycoprotein is expressed as part of the normal blood-brain barrier in the luminal membranes of the cerebral capillary endothelial cells, where it presumably performs a protective function for the brain. This report describes the functional expression of P-glycoprotein in an immortalised cell line, RBE4, derived from rat cerebral capillary endothelial cells. The expression of P-glycoprotein is demonstrated by western immunoblotting and by immunogold and fluorescent staining with monoclonal antibodies. The cellular accumulation of [3H]colchicine and [3H]-vinblastine is investigated and shown to be enhanced by the presence of azidothymidine, chlorpromazine, verapamil, cyclosporin A, and PSC 833 ([3'-keto-Bmt1]-[Val2]-cyclosporin) at 50 or 100 microM concentration. It is concluded that the RBE4 cell line is a valuable tool for investigating the mechanisms of P-glycoprotein activity both in the blood-brain barrier and in multidrug resistance in general.
细胞质膜中P-糖蛋白的存在限制了许多细胞毒性物质进入表达该基因产物的细胞。也有大量证据表明，P-糖蛋白在脑毛细血管内皮细胞的管腔膜中作为正常血脑屏障的一部分表达，它可能在那里为大脑发挥保护作用。本报告描述了P-糖蛋白在源自大鼠脑毛细血管内皮细胞的永生化细胞系RBE4中的功能性表达。通过蛋白质免疫印迹以及用单克隆抗体进行免疫金和荧光染色来证明P-糖蛋白的表达。研究了[3H]秋水仙碱和[3H]长春碱在细胞内的积累情况，结果表明，浓度为50或100微摩尔的叠氮胸苷、氯丙嗪、维拉帕米、环孢素A和PSC 833（[3'-酮基-Bmt1]-[Val2]-环孢素）可增强这种积累。得出的结论是，RBE4细胞系是研究血脑屏障中P-糖蛋白活性机制以及一般多药耐药性机制的宝贵工具。
