Ectopic EBP2 expression enhances cyclin E1 expression and induces chromosome instability in HEK293 stable clones

• Published in: BMB reports 2008-10, Vol.41 (10), p.716-721
• Main Authors: Lee, M.C. (National Taiwan University, Taipai, Taiwan), Hsieh, Chang-Hsun (National Taiwan University, Taipai, Taiwan), Wei, Shu-Chen (National Taiwan University Hospital, Taipai, Taiwan), Shen, Shu-Chen (National Taiwan University Hospital, Taipai, Taiwan), Chen, Chiung-Nien (National Taiwan University Hospital, Taipai, Taiwan), Wu, Vin-Cent (National Taiwan University Hospital, Taipai, Taiwan), Chuang, Li-Ying (National Taiwan University Hospital, Taipai, Taiwan), Hsieh, Fon-Jou (National Taiwan University Hospital, Taipai, Taiwan), Wu, C. H. Herbert (National Taiwan University, Taipai, Taiwan), Tsai-Wu, Jyy-Jih (National Taiwan University Hospital, Taipai, Taiwan), E-mail: [e-mail]
• Format: Article
• Language: English
• Subjects: Ataxia Telangiectasia Mutated Proteins; Carrier Proteins - metabolism; Cell Cycle Proteins - metabolism; Cell Line; CELLS; CELLULE; CELULAS; Chromosomal Instability; Chromosome instability; Chromosomes, Human - metabolism; Clone Cells; Cyclin E - metabolism; Cyclin E1; Cyclin-Dependent Kinase 2 - metabolism; Cyclin-Dependent Kinase Inhibitor p21 - metabolism; DNA-Binding Proteins - metabolism; EBP2; Green Fluorescent Proteins - metabolism; Humans; Oncogene Proteins - metabolism; p53-p21 system; Protein-Serine-Threonine Kinases - metabolism; Recombinant Fusion Proteins - metabolism; Tumor Suppressor Protein p53 - metabolism; Tumor Suppressor Proteins - metabolism; Tumorigenesis
• ISSN: 1976-6696
• DOI: 10.5483/BMBRep.2008.41.10.716

To explore the effects of deregulated expression of the EBNA1 binding protein 2 (EBP2) on cell growth, we generated human HEK293 stable clones constitutively expressing an EBP2-EGFP fusion protein. We found both RNA and protein levels of cyclin E1, a dominant oncoprotein, were elevated in the EBP2-EGFP stable clones. These findings were confirmed by flow cytometry bivariate analysis of cyclin expression versus DNA content. Moreover, the increase in p21 expression and the specific phosphorylation at Ser1981 of ATM and Ser15 of p53 were also observed in these stable clones, and these observations may explain the failure to observe an increase in Cdk2 kinase activity. In addition, after one year of passage culture, the EBP2-EGFP stable clones tended to lose 4 to 5 chromosomes per cell when compared to that of control cells. All of these findings provide a possible link between deregulated expression of EBP2 and tumor development.