The Epstein-Barr virus oncogene product, latent membrane protein 1, induces the downregulation of E-cadherin gene expression via activation of DNA methyltransferases.
The latent membrane protein (LMP1) of Epstein-Barr virus (EBV) is expressed in EBV-associated nasopharyngeal carcinoma, which is notoriously metastatic. Although it is established that LMP1 represses E-cadherin expression and enhances the invasive ability of carcinoma cells, the mechanism underlying this repression remains to be elucidated. In this study, we demonstrate that LMP1 induces the expression and activity of the DNA methyltransferases 1, 3a, and 3b, using real-time reverse transcription-PCR and enzyme activity assay. This results in hypermethylation of the E-cadherin promoter and down-regulation of E-cadherin gene expression, as revealed by methylation-specific PCR, real-time reverse transcription-PCR and Western blotting data. The DNA methyltransferase inhibitor, 5'-Aza-2'dC, restores E-cadherin promoter activity and protein expression in LMP1-expressing cells, which in turn blocks cell migration ability, as demonstrated by the Transwell cell migration assay. Our findings suggest that LMP1 down-regulates E-cadherin gene expression and induces cell migration activity by using cellular DNA methylation machinery.
Tsai
Chi-Neu
CN
Graduate Institute of Basic Medical Sciences, Chang-Gung University, Kwei-shan, Taoyuan, Taiwan 333, Republic of China.
Tsai
Chia-Lung
CL
Tse
Ka-Po
KP
Chang
Hwan-You
HY
Chang
Yu-Sun
YS
D000818:Animals; D000956:Antigens, Viral / Q000235:genetics; D015820:Cadherins / Q000235:genetics*; D002460:Cell Line; D017931:DNA Primers; D015257:DNA-Cytosine Methylases / Q000378:metabolism*; D004285:Dogs; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D004854:Herpesvirus 4, Human / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014763:Viral Matrix Proteins / Q000235:genetics* / Q000378:metabolism
D000956:Antigens, Viral; D015820:Cadherins; D017931:DNA Primers; C037662:EBV-associated membrane antigen, Epstein-Barr virus; D011994:Recombinant Proteins; D014763:Viral Matrix Proteins; D015257:DNA-Cytosine Methylases