Woodworth C D, Kreider J W, Mengel L, Miller T, Meng Y L, Isom H C
Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey 17033.
Mol Cell Biol. 1988 Oct;8(10):4492-501. doi: 10.1128/mcb.8.10.4492-4501.1988.
Five simian virus 40 (SV40)-hepatocyte cell lines were examined for tumorigenicity and the effect of in vitro passage on the expression of four liver-specific genes (albumin, transferrin, alpha 1-antitrypsin, and phosphoenolpyruvate carboxykinase), two oncogenes (c-Ha-ras and c-raf), and two genes associated with hepatocarcinogenesis (alpha-fetoprotein and placental-type glutathione-S-transferase). At low passage (12 to 22), all five cell lines expressed the four liver-specific genes at levels similar to those in the liver and were not tumorigenic or were weakly tumorigenic. At high passage (33 to 61), the cell lines formed carcinomas, and four out of five cell lines produced primary tumors that metastasized. At least two cell lines produced well-differentiated hepatocellular carcinomas that expressed liver-specific RNAs. Levels of expression of liver-specific genes changed with time in culture. Some of the changes in liver-specific gene expression in the tumor tissue (such as for the phosphoenolpyruvate carboxykinase gene) paralleled those that occurred with in vitro passage, while other changes (such as for the albumin gene) did not parallel those that occurred with in vitro passage. Correlations between enhanced expression of c-Ha-ras and tumorigenic potential and between the process of SV40 immortalization and induced expression of c-raf and glutathione-S-transferase-P were observed. Induction of alpha-fetoprotein was detected with in vitro and in vivo passage only in the CWSV14 cell line and was paralleled by diminished albumin expression. In conclusion, we developed a model system with five SV40-hepatocyte cell lines, tumors induced by them, and tumor cell lines to examine changes in gene expression that accompany the progression from a normal cell to a hepatocellular carcinoma. Because the SV40-hepatocyte cell lines and tumor cell lines remain highly differentiated and vary in the magnitude of expression of specific genes, they can be used to study the molecular mechanisms regulating gene expression, in particular those regulating specific genes associated with differentiation.
对五个猿猴病毒40（SV40）-肝细胞系进行了致瘤性检测，以及体外传代对四个肝脏特异性基因（白蛋白、转铁蛋白、α1-抗胰蛋白酶和磷酸烯醇丙酮酸羧激酶）、两个癌基因（c-Ha-ras和c-raf）和两个与肝癌发生相关基因（甲胎蛋白和胎盘型谷胱甘肽-S-转移酶）表达的影响。在低传代（12至22代）时，所有五个细胞系表达四个肝脏特异性基因的水平与肝脏中的水平相似，且不具有致瘤性或致瘤性较弱。在高传代（33至61代）时，细胞系形成癌，五个细胞系中有四个产生了发生转移的原发性肿瘤。至少两个细胞系产生了表达肝脏特异性RNA的高分化肝细胞癌。肝脏特异性基因的表达水平随培养时间而变化。肿瘤组织中肝脏特异性基因表达的一些变化（如磷酸烯醇丙酮酸羧激酶基因）与体外传代时发生的变化相似，而其他变化（如白蛋白基因）则与体外传代时发生的变化不同。观察到c-Ha-ras表达增强与致瘤潜能之间以及SV40永生化过程与c-raf和谷胱甘肽-S-转移酶-P诱导表达之间存在相关性。仅在CWSV14细胞系中检测到体外和体内传代时甲胎蛋白的诱导，同时白蛋白表达减少。总之，我们建立了一个模型系统，包括五个SV40-肝细胞系、由它们诱导产生的肿瘤以及肿瘤细胞系，以研究从正常细胞发展为肝细胞癌过程中伴随的基因表达变化。由于SV40-肝细胞系和肿瘤细胞系保持高度分化，且特定基因表达量存在差异，它们可用于研究调节基因表达的分子机制，特别是那些调节与分化相关特定基因的机制。
