title: Mouse embryonic stem cells induce targeted DNA demethylation within human MAGE-A1 transgenes.
abstract: Human tumor development is often associated with a DNA demethylation process. This results in the activation of germline-specific genes, such as MAGE-A1, which rely on DNA methylation for repression in somatic tissues. Here, we searched to identify a cell line possessing ongoing DNA demethylation activity targeted to MAGE-A1. We first assessed MAGE-A1-expressing human tumor cell lines, by evaluating their ability to induce demethylation of MAGE-A1 transgenes that were methylated in vitro before transfection. All cell lines lacked such activity, suggesting that MAGE-A1 hypomethylation in tumors results from a past demethylation event. We then turned to mouse embryonic stem (mES) cells, which are characterized by a high level of methylation plasticity. Interestingly, in vitro methylated MAGE-A1 transgenes became demethylated after transfection into mES cells. Demethylation was targeted to the 5'-region of MAGE-A1 and was strongly reduced at mutated MAGE-A1 transgenes exhibiting impaired promoter activity. Our results indicate that mES cells induce demethylation of MAGE-A1 and represent therefore a valuable system to study this tumor-related process.
authors: Cellular Genetics Unit, de Duve Institute, Université Catholique de Louvain, Brussels, Belgium.
authors: Axelle
authors: A
authors: Loriot
authors: Christiane
authors: C
authors: Sterpin
authors: Olivier
authors: O
authors: De Backer
authors: Charles
authors: C
authors: De Smet
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000378:metabolism*; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D058950:Melanoma-Specific Antigens; D051379:Mice; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D019076:Transgenes
chemical_list: D000951:Antigens, Neoplasm; D004273:DNA, Neoplasm; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins