转铁蛋白结合镱跨膜转运及镱对U-87MG细胞增殖的影响

目的:研究转铁蛋白/转铁蛋白受体转运系统对转铁蛋白结合镱(Yb₂Tf)跨膜转运进入神经胶质瘤U-87MG细胞,以及转铁蛋白结合镱和非转铁蛋白结合镱对U-87MG细胞增殖的影响。方法:细胞培养及ICP-MS镱测定法。结果:随Yb₂Tf浓度增加,细胞镱摄入量增加。当浓度达2μmol/L时,细胞摄取镱基本达到饱和状态。细胞摄入镱量也随镱:apoTf摩尔比增大而增加,当摩尔比达到1.5时,摄入量达到最高水平。0.4μmol/LYb₂Tf可显著抑制U-87MG细胞增殖,而Yb³⁺浓度高达10μmol对细胞增殖仅有轻微影响。结论:转铁蛋白/转铁蛋白受体介导的膜转运可能是镱跨越U-87MG细胞的机制之一。转铁蛋白结合Yb³⁺可以有效地抑制U-87MG细胞的增殖。

Transferrin - bound Yb2 uptake by U - 87 MG cells and effect of Yb on proliferation of the cells

AIM:To investigate the role of transferrin/transferrin receptor system in transferrin-bound Yb₂ (Yb₂Tf) uptake by U-87 MG cells and the effect of transferrin-bound and -free Yb₂ on proliferation of U-87 MG cells.METHODS:Cell culture and ICP-MS measurement of Yb₂.RESULTS:Yb₂Tf uptake by U-87 MG cells increased with the concentrations of Yb₂Tf, and reached saturation as the concentration in the incubation medium was raised to about 2 μmol/L. Also, Yb₂ uptake by the cells increased with increase of the mole ratio (Yb₂: apoTf), reaching a maximum at 1.5 mole ratio. Yb₂Tf in 0.4 μmol/L significantly inhibited proliferation of U-87 MG cells, however, 10 μmol/L Yb³⁺ had no significant effect on proliferation of the cells.CONCLUSION:The uptake of Yb₂ by U-87 MG cells might be mediated by transferrin/transferrin receptor system. Transferrin-bound but not transferrin-free Yb₂ could significantly inhibit proliferation of U-87 MG cells.