Inoue H, Tavoloni N, Hanafusa H
Laboratory of Molecular Oncology, Rockefeller University, New York, New York 10021, USA.
Oncogene. 1995 Jul 20;11(2):231-8.
To understand the mechanism for resistance of primary cultures of rat embryo fibroblasts (REFs) to oncogene-induced transformation, we studied the transforming ability of a recombinant retrovirus, ZSV, containing v-src and neo genes in REFs and in the rat cell line F2408. The susceptibility of REFs to p60v-src transformation was markedly reduced when compared with that of F2408 cells, despite high levels of expression of functional p60v-src tyrosine kinase in the two systems. In hybrid cells obtained by somatic cell fusion between F2408 cells transformed by v-src and uninfected REFs, the transformed phenotype was suppressed despite persistent expression of p60v-src tyrosine kinase. On the other hand, hybrid cells between v-src transformed F2408 cells and uninfected F2408 cells retained the transformed phenotypes. These results indicate that primary cells possess an intracellular function(s) that cause suppression of the transformed phenotype induced by the v-src gene. In ZSV-infected REFs, tyrosine phosphorylation of cellular proteins, including p125 focal adhesion kinase, p70 paxillin and p130 was similar to that in the ZSV-infected F2408 cells, indicating that tyrosine phosphorylation of these proteins is not sufficient for the expression of transformed phenotype. On the other hand, cellular fibronectin and one of integrin receptors were downregulated in the ZSV-transformed F2408 cells but not in ZSV-infected REFs, suggesting that fibronectin and/or its receptor might play a role in suppressing v-src transformation in primary rat cells.
为了解大鼠胚胎成纤维细胞（REFs）原代培养物对癌基因诱导转化产生抗性的机制，我们研究了一种含有v-src和neo基因的重组逆转录病毒ZSV在REFs和大鼠细胞系F2408中的转化能力。与F2408细胞相比，REFs对p60v-src转化的敏感性显著降低，尽管在这两个系统中功能性p60v-src酪氨酸激酶的表达水平都很高。在由v-src转化的F2408细胞与未感染的REFs通过体细胞融合获得的杂交细胞中，尽管p60v-src酪氨酸激酶持续表达，但转化表型受到抑制。另一方面，v-src转化的F2408细胞与未感染的F2408细胞之间的杂交细胞保留了转化表型。这些结果表明原代细胞具有一种细胞内功能，可导致v-src基因诱导的转化表型受到抑制。在ZSV感染的REFs中，包括p125粘着斑激酶、p70桩蛋白和p130在内的细胞蛋白的酪氨酸磷酸化与ZSV感染的F2408细胞中的相似，这表明这些蛋白的酪氨酸磷酸化不足以表达转化表型。另一方面，细胞纤连蛋白和整合素受体之一在ZSV转化的F2408细胞中下调，但在ZSV感染的REFs中未下调，这表明纤连蛋白和/或其受体可能在抑制原代大鼠细胞中的v-src转化中发挥作用。
