肝细胞癌变时神经节苷脂对转铁蛋白受体介导的内吞作用的影响

Effect of gangliosides on transferrin receptor mediated endocytosis in hepatoma cells

目的：研究肝细胞癌变时神经节苷脂ＧＭ３和ＧＤ３的变化对转铁蛋白受体介导的内吞作用的影响及其在促进肝癌生长中所起的作用。方法：采用放射性核素标记配体受体结合法，及洗脱法测定转铁蛋白与其受体的结合以及转铁蛋白受体介导的内吞作用；用ＭＴＴ比色法测定细胞生长情况。结果：（１）ＧＭ３抑制肝癌细胞的生长，ＧＤ３则促进肝癌细胞的生长；（２）这种影响与转铁蛋白对细胞的作用直接相关；（３）此相关作用不是通过影响转铁蛋白与其受体的结合，而是通过影响转铁蛋白受体介导的内吞作用而实现的。结论：肝细胞癌变时神经节苷脂组成的变化能明显加快转铁蛋白受体介导的内吞作用，增加肝癌细胞对转铁蛋白的摄取，从而促进肝癌细胞的生长与增殖。

Objective: To study the effect of gangliosides GM 3 and GD 3 on transferrin receptor medicated endocytosis in hepatoma cells and its role in tumor growth.Methods: The effects of GM 3 and GD 3 on cell growth, transferrin binding to its receptor and transferrin receptor mediated endocytosis were investigated by biochemistry and cell culture techniques.Results:The changes of gangliosides GM 3 and GD 3 in HCC could promote cell growth and are directly related with the effect of transferrin on HCC cells. Mechanism study indicated that the changes of gangliosides had no effect on binding of transferrin to its receptors but could accelerate the endocytosis of transferrin receptors and transferrin uptake.Conclusion:This may be one of the reasons that changes of gangliosides in hepatoma cells could promote HCC growth.