Hocher B, Abou-Rebyeh H, Plaum M, Fakhury M, Schiller S, Bauer C
Abteilung für Allgemeine Innere Medizin und Nephrologie, Universitätsklinikum Benjamin Franklin, Freien Universität Berlin, Germany.
Eur J Clin Chem Clin Biochem. 1994 Sep;32(9):697-704. doi: 10.1515/cclm.1994.32.9.697.
Altered expression of protooncogenes/oncogenes is believed to be involved in hepatocarcinogenesis of the chemically induced, transplantable Morris hepatoma 7777. We compared the mRNA expression of c-N-ras and v-erb B mRNA of normal rat liver with that of Morris hepatoma 7777 using Northern blot analysis and in situ hybridization. Northern blot analysis revealed a strong overexpression of the v-erb B related mRNA, while the c-N-ras mRNA was only slightly increased. In situ hybridization using a c-N-ras mRNA probe also showed only a slightly increased number of silver grains in the hepatoma cells compared with normal rat liver. On the other hand, the v-erb B related mRNA was strongly overexpressed in the hepatoma cells, while the connective-tissue capsule, the blood vessels, blood cells and the necrotic foci did not show an elevated v-erb B related gene mRNA expression. Similar results were obtained in liver metastases. The detectable v-erb B hybridization signal was lost by pretreatment with RNase A. We conclude that the c-N-ras gene is of minor importance in the chemically induced, transplantable Morris hepatoma 7777, while the increased expression of the v-erb B related mRNA is due to a selection of ligand-independent tyrosine kinase activity.
原癌基因/癌基因的表达改变被认为与化学诱导的、可移植的莫里斯肝癌7777的肝癌发生有关。我们使用Northern印迹分析和原位杂交技术，比较了正常大鼠肝脏与莫里斯肝癌7777中c-N-ras和v-erb B mRNA的表达。Northern印迹分析显示v-erb B相关mRNA有强烈的过表达，而c-N-ras mRNA仅略有增加。与正常大鼠肝脏相比，使用c-N-ras mRNA探针进行的原位杂交也显示肝癌细胞中银颗粒的数量仅略有增加。另一方面，v-erb B相关mRNA在肝癌细胞中强烈过表达，而结缔组织包膜、血管、血细胞和坏死灶未显示v-erb B相关基因mRNA表达升高。在肝转移中也获得了类似的结果。用核糖核酸酶A预处理后，可检测到的v-erb B杂交信号消失。我们得出结论，c-N-ras基因在化学诱导的、可移植的莫里斯肝癌7777中不太重要，而v-erb B相关mRNA表达的增加是由于选择了不依赖配体的酪氨酸激酶活性。
