Braun L, Goyette M, Yaswen P, Thompson N L, Fausto N
Cancer Res. 1987 Aug 1;47(15):4116-24.
Two epithelial cell lines designated LE/2 and LE/6 were established from cells isolated by centrifugal elutriation from the livers of carcinogen-treated rats. Both cell lines exhibit some characteristics of fetal liver cells, such as the expression of the 2.3-kilobase alpha-fetoprotein mRNA, aldolase A, and lactate dehydrogenases 4 and 5. Primary cultures contain gamma-glutamyl transferase-positive cells which do not proliferate in vitro. After the first passage, the LE/2 and LE/6 cell lines are uniformly gamma-glutamyl transferase negative. Neither cell line is transformed as assayed by morphology, anchorage-independent growth, or tumor formation in nude mice. By the 50th passage, LE/6 cells form numerous colonies in soft agar in the presence of epidermal growth factor, while no colonies grow in medium lacking this growth factor. Clonal cell populations derived from five epidermal growth factor-induced soft agar colonies were not tumorigenic in nude mice. This indicates that, although epidermal growth factor-responsive late passage cells had acquired some of the phenotypic properties commonly associated with tumor cells, these cells were not fully transformed. Transformation of LE/6 cells was accomplished by transfection of the rasH oncogene (EJ). Subcutaneous inoculation of rasH (EJ)-transfected LE/6 cells produced tumors at the site of injection with histological features of moderate to well-differentiated trabecular hepatocellular carcinomas. Tumor cell lines derived from the nude mouse tumors are gamma-glutamyl transferase positive and express alpha-fetoprotein mRNA. One clonal cell line expresses both alpha-fetoprotein and albumin mRNA. These results show that nonparenchymal liver epithelial cells transfected with an activated oncogene can give rise to differentiated hepatocellular tumors similar to those induced in livers of rats fed a carcinogenic diet.
从经致癌物处理的大鼠肝脏中通过离心淘析分离得到的细胞建立了两种上皮细胞系，分别命名为LE/2和LE/6。这两种细胞系均表现出胎儿肝细胞的一些特征，如2.3千碱基甲胎蛋白mRNA、醛缩酶A以及乳酸脱氢酶4和5的表达。原代培养物中含有γ-谷氨酰转移酶阳性细胞，这些细胞在体外不增殖。首次传代后，LE/2和LE/6细胞系均一致为γ-谷氨酰转移酶阴性。通过形态学、不依赖贴壁生长或裸鼠肿瘤形成检测，这两种细胞系均未发生转化。到第50代时，LE/6细胞在表皮生长因子存在的情况下于软琼脂中形成大量集落，而在缺乏该生长因子的培养基中则无集落生长。源自五个表皮生长因子诱导的软琼脂集落的克隆细胞群体在裸鼠中不具有致瘤性。这表明，尽管对表皮生长因子有反应的传代后期细胞获得了一些通常与肿瘤细胞相关的表型特性，但这些细胞并未完全转化。LE/6细胞的转化是通过转染rasH癌基因（EJ）实现的。皮下接种rasH（EJ）转染的LE/6细胞在注射部位产生肿瘤，其组织学特征为中度至分化良好的小梁状肝细胞癌。源自裸鼠肿瘤的肿瘤细胞系γ-谷氨酰转移酶呈阳性并表达甲胎蛋白mRNA。一个克隆细胞系同时表达甲胎蛋白和白蛋白mRNA。这些结果表明，用活化癌基因转染的非实质肝上皮细胞可产生类似于给喂食致癌饮食的大鼠肝脏中诱导产生的分化型肝细胞肿瘤。
