人胃癌细胞膜表皮生长因子受体的表达

Expression of Epidermal Growth Factor Receptor in the Surface of Human Gastric Cancer Membrane

用^(125)Ⅰ标记的人类表皮生长因子(^(125)Ⅰ-EGF)与分离制备的胃癌和癌旁组织细胞膜进行放射配体结合试验。胃癌细胞膜^(125)Ⅰ-EGF结合量为13.5±3.84fmol/mg膜蛋白,癌旁组织为6.15±1.65fmol/mg膜蛋白,两者差异显著(22例,t=8.25,P<0.01)。高分化组胃癌^(125)Ⅰ-EGF结合量显著低于低分化组胃癌(P<0.05)。Scatchard分析表明,胃组织细胞膜EGF受体是一种单一亲和力的受体。胃癌^(125)Ⅰ-EGF最大结合力(B_(max)=26.15±2.17fmol/mg膜蛋白)高于癌旁正常组织(B_(max)=19.87±2.81 fmol/mg膜蛋白),两者差异显著(t=2.95,P<0.05)。胃癌EGF受体的亲和力(K_D=11.13±0.22nM)大于癌旁正常组织(K_D=1.79±0.23nM),两者差异显著(t=3.59,P<0.05)。本研究表明,胃癌细胞膜表面EGF受体在数量和亲和力两方面都有显著改变,提示在胃癌的发生发展过程中。

The membrane of gastric cancer and nonneoplastic tissues beside the cancer were bound by 125 I labeled human epidermal growth factor (125I -EGF) in a test of radio ligand binding assay. The values of 125I-EGF binding were 13.51±3.84 fmol/mg membrane protein in gastric cancer and 6.15±1.65 fmol/mg membrane protein in nonneoplastic tissues, the difference was significant (n=22,t=8.25, P< 0.01). Scatchard analysis of 125I -EGF binding indicated a single class of receptors in both gastric cancer and nonneoplastic tissues. The binding capacities in carcinoma and nonneoplastic tissues were 26.15±2.17 fmol/mg membrane protein and 19.87±2.81 fmol/mg membrane protein respectively, the difference was significant (n=3,t= 2.95, P<0.05). The affinities of gastric cancer (KD=1.13±0.22 nM) were significantly higher than that of nonneoplastic tissues (KD=1.79±0.23 nM). The present study suggestted that an auto/paracrine loops of self-proliferation by EGF and its receptor played an important role in gastric cancer growth regulation.