FRA1 is a determinant for the difference in RAS-induced transformation between human and rat fibroblasts
FRA1 is a determinant for the difference in RAS-induced transformation between human and rat fibroblasts
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DOI：
10.1073/pnas.0601222103
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发表时间：
2006-04-04
影响因子：
11.1
通讯作者：
Akagi, T
中科院分区：
文献类型：
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作者：
Kakumoto, K;Sasai, K;Akagi, T
与SV 40 ER永生化的大鼠胚胎成纤维细胞（REF）相比，hTERT和猴病毒40（SV 40）早期区（ER）永生化的人二倍体成纤维细胞（HDF）在表达活化的H-RAS（H-RAS V12）后表现出有限程度的转化。在这里，我们确定FRA 1作为RAS诱导转化的这种差异的决定因素。FRA 1在永生化HDF中不被H-RAS V12诱导，相反，其在永生化REF中显著蓄积。FRA 1的异位表达显著增强了表达hTERT、SV 40 ER和H-RAS V12的各种HDF的锚定非依赖性生长。更重要的是，FRA 1可以诱导锚定非依赖性生长以及裸鼠肿瘤形成的永生化HDF在H-RAS V12的情况下。体外激酶测定的结果清楚地表明，RAS诱导的细胞外信号调节激酶（ERK）激活，这是负责FRA 1诱导，显着减弱HDF与REF相比，尽管没有明显的差异，在物种之间的ERK磷酸化状态。我们的研究结果强烈表明，HDF负调节丝裂原活化蛋白激酶激酶（MEK）/ERK途径比REF更有效，因此表达较少的恶性表型响应H-RAS V12。
Human diploid fibroblasts (HDF) immortalized by hTERT and simian virus 40 (SV40) early region (ER) exhibit a limited degree of transformation upon the expression of activated H-RAS (H-RAS V12) compared with rat embryonic fibroblasts (REF) immortalized by SV40 ER. Here, we identified FRA1 as a determinant for this difference in RAS-induced transformation. FRA1 was not induced by H-RAS V12 in the immortalized HDF, in contrast to its marked accumulation in the immortalized REF. Ectopic expression of FRA1 significantly enhanced anchorage-independent growth of various HDF expressing hTERT, SV40 ER, and H-RAS V12. More importantly, FRA1 could induce anchorage-independent growth as well as nude mice tumor formation of the immortalized HDF in the absence of H-RAS V12. The results of an in vitro kinase assay clearly showed that the RAS-induced extracellular signal-regulated kinase (ERK) activation, which is responsible for FRA1 induction, was markedly attenuated in the HDF compared with that in the REF, despite no obvious differences in the phosphorylation status of ERK between the species. Our results strongly suggest that HDF negatively regulate the mitogen-activated protein kinase kinase (MEK)/ERK pathway more efficiently than REF, and consequently express less malignant phenotypes in response to H-RAS V12.