成纤维细胞表皮生长因子的胞吞和向细胞核转移研究

本文以C3H小鼠胚胎正常成纤维细胞株C3H10T1/2C18(简称NC3H10)及其由氚标记脱氧胸苷(~3H-TdR)恶性转化的细胞株(简称TC 3H 10)为对象,研究了表皮生长因子(EGF)在受体介导下的胞吞和向细胞核转移现象。~(125)I-EGF 与细胞膜上的EGF 受体结合后,胞吞和向细胞核转移呈时间依赖性。两种细胞的EGF 的胞吞和向细胞核转移率接近。但是NC 3 H 10细胞~(125)I-EGF 胞知和向细胞核转移的绝对量明显高于TC 3 H 1 0细胞(p<0.05)。SDS-PAGE 电泳表明向细胞核转移的~(125)I-EGF 是未被降解的完整分子,溶酶体抑制剂NH_4Cl 对~(125)I-EGF 向细胞核转移有明显促进作用(p<0.05)。这些结果表明受体介导下的EGF 胞吞和向细胞核转移可能与EGF 的细胞核内凋节作用密切相关。

STUDY ON ENDOCYTOSIS AND NUCLEAR ACCUMULATION OF EPIDERMAL GROWTH FACTOR(EGF)IN NORMAL C3H MOUSE FIBROBLAST CELLS C3 H10 T1/2 C 1 8 AND 3 H-TdR TRANSFORMED COUNTERPART CELLS

In this study,we investigated endo-cytosis and nuclear accumulation of epider-mal growth factor(EGF)in normal C3Hmouse embryo fibroblast cells C3H10T1/2 C18(designated NC3H10)and ~3H-TdR transformed counterpart cells(designa-ted TC3H10).The results revealed that~(125)I-labelled EGF bound to the receptoron the cell surface of the two cell lineswas subsequently endocytosed and translo-cated from the cell membrane to the nuc-leus,where it progressively accumulated.NC3H10 showed more EGF accumulationin nucleus than TC3H10(p<0.05).SDS-polyacrylamide gel electrophoresis re-vealed that the endocytosed ~(125)I-EGF asso-ciated with the nucleus was intact,withnegligible breakdown products present.Thenuclear accumulation of intact EGF in thementioned cell lines exposed to ammoniumchloride(a lysosomal inhibitor)was hig-her than the control(p<0.05).These re-sults suggested that receptor-mediated endo-cytosis and nuclear accumulation of EGFmay play an important role in mediationsome of the action of EGF.