非促有丝分裂型人酸性成纤维细胞生长因子的受体结合特性及对MAPK信号通路的影响

目的:研究非促分裂人酸性成纤维细胞生长因子(non- mitogenetichumanacidicfibroblastgrowthfac tor,nm haFGF)促细胞增殖活性的变化及其作用机制。方法:采用MTT法测定人酸性成纤维细胞生长因子(haFGF)和nm- haFGF对NIH3T3细胞株的增殖活性;采用受体放射性配基结合法,测定haFGF和nm- haFGF与其受体结合的亲和力及受体总结合位点数RT ;利用Western印迹检测haFGF和nm- haFGF分别作用于NIH3T3细胞后MAPK信号通路中ERK信号分子的表达。结果:与haFGF比较,nm- haFGF对NIH3T3细胞的促增殖活性降低,nm -haFGF与NIH3T3细胞胞膜上aFGF受体结合的亲和力下降,但与受体结合的总位点数不变。Western半定量检测结果显示,nm -haFGF组信号蛋白ERK的表达水平明显低于haFGF组。结论:nm -haFGF与受体结合能力下降,下调MAPK信号通路是导致nm haFGF的促分裂活性降低的主要原因之一。

Receptor Binding Character of Non-mitogenetic Acidic Fibroblast Growth Factor and Its Effects on MAPK Signal Pathway

AIM:To study the mitogenesis and its mechanism of n on-mitogenetic human acidic fibroblast growth factor (nm-haFGF).MEHTO D:The mitogenic effects of human acidic fibroblast growth factor (haFGF) and nm-haFGF on NIH3T3 cells were measured by MTT.The receptors affinity (Kd an d IC 50) and the number of binding receptors (RT) of haFGF and nm-haFGF we re assessed by radio-ligand binding assay of receptors. The expression of the MAPK si gnal protein ERK 1/2 induced respectively by haFGF and nm-haFGF was det ected by Western-blot.RESULT:The mitogenic effect of nm-haFGF on NIH3T3 cells was reduced if compared to that of haFGF. The receptors affin ity of nm-haFGF was found to be decreased, while the number of binding receptors (RT) of nm-haFGF remained unchanged. The results of Western-blot showed that t he expression le vel of ERK of the nm-haFGF treated group was lower than that of the haFGF treat ed group.CONCLUSION:The decline of the receptor-binding affinity and down-regulation of the MAPK signal pathway were mainly responsible for the decrease of the mitogenic activity of nm-haFGF.