Ets1 was significantly activated by ERK1/2 in mutant K-ras stably transfected human adrenocortical cells.
In our previous study on the tumorigenesis of human functional adrenal tumors, we observed a high frequency of point mutation in the K-ras gene in clinical adrenal tumors. Therefore, we analyzed gene profiles of mutant K-ras transfected adrenocortical cells by DNA microarray to determine the expression pattern of genes related to cell cycle, signal transduction, apoptosis, tumorigenesis, steroidogenesis, and other expressed sequence tags (ESTs). Then we analyzed all of the significant differentially expressed genes by bioinformatics tools, "Matchminer" and "Gominer." The results revealed that expression of mutant K-ras gene induced by IPTG upregulated Ets1, which was mainly related to cell proliferation. After carefully being analyzed by software "DAVID" and "Pathart," Ets1 was found to be activated by being phosphorylated at theronine 38 by ERK1/2, and in turn, to regulate the following genes: uPA, MMP-3, and prolactin (Ling et al., 2003; Duffy and Daggan, 2004; Maupas-Schwalm et al., 2004; van Themsche et al., 2004). The result of Western blotting analysis confirmed that Ets1 was really phosphorylated when mutant K-ras was activated. On the other hand, the membrane blotting analyses indicated that the expression levels of uPA, MMP-3, and prolactin in human adrenocortical cells stably transfected with the mutant K-ras gene were significantly higher than those in normal control cells. Compared to control cells, the level of prolactin raised 1.4-fold, the level of MMP-3 raised 1.8-fold, and the level of uPA raised 2.1-fold in the transfected cells. From the results of this study, we proposed a mechanism of Ets1 in human adrenocortical cells expressing a mutated K-ras gene.
Chen
Y-F
YF
MedicoGenomic Research Center, Kaohsiung, Taiwan.
Shin
S-J
SJ
Lin
S-R
SR
D000302:Adrenal Cortex / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D000306:Adrenal Cortex Neoplasms / Q000235:genetics; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D006801:Humans; D019278:Matrix Metalloproteinase 3 / Q000235:genetics; D019950:Mitogen-Activated Protein Kinase 1 / Q000502:physiology*; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000502:physiology*; D009154:Mutation / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D010766:Phosphorylation; D011388:Prolactin / Q000235:genetics; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D050783:Proto-Oncogene Proteins c-ets; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics* / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D015854:Up-Regulation
C494041:ETS1 protein, human; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D014157:Transcription Factors; D011388:Prolactin; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D019278:Matrix Metalloproteinase 3; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras)