人上皮样胃癌细胞株与人正常上皮细胞LDL受体的分析比较

COMPARISON OF THE LOW-DENSITY-LIPOPROTEIN RECEPTOR ACTIVITY IN HUMAN EPITHELIOID GASTRIC CARCINOMA CELL LINES AND IN HUMAN NORMAL EPITHELIOID CELLS

用放射性配体分析法测定了胃癌细胞株ＳＧＣ－７９０１、ＮＫＭ－４５的ＬＤＬ受体、ＬＤＬ内移及降解量，并与正常的胃粘膜细胞和建株的人羊膜细胞对照。结果表明，胃癌细胞株ＬＤＬ受体的Ｋｄ值与对照细胞相似，最大结合量较正常细胞显著增加，分别为４１２．０２（ＳＧＣ－７９０１）、３８４．４３（ＮＫＭ－４５）、２９１．０７（胃粘膜细胞）及２９１．４２μｇ／ｇ细胞蛋白（羊膜细胞），胃癌细胞的ＬＤＬ内移及降解量较正常细胞明显增加。提示胃癌细胞株ＳＧＣ－７９０１及ＮＫＭ－４５受体介导的ＬＤＬ代谢率增强，ＬＤＬ受体数量增加，受体对ＬＤＬ的亲和性、特异性与正常细胞之间差异无显著性。

in this experiment,the authors compared the LDLR activity in two human epithelioid gastric carcinoma cell lines (SGC-7901,NKM-45)and two human normal epithelioid cells (amnionic cell line,gastric mucosal cells derived from tissue culture )with the methods of saturation analysis. It was found that the uptake and degradation of 125I LDL in carcinoma cell line(SGC-7901 and NKM-45)was obviously higher than that in normal cells. The maximum binding of LDL for the four different cell types were 412. 02(SGC-7901 ), 384. 43 (NKM-45), 291. 07 (gastric mucosal cell ), and 291. 42μg/g cell protein(amnionic cell)respectively, which indicated that the LDLR level was increased in carcinoma cells. The results also showed that the equilibrium dissociation constant(Kd) value in carcinoma cells were similar to that in normal cells,demonstrating the LDLR affinity and specifity was similar in both carcinomal and normal cells.