title: Activating transcription factor 2 mediates matrix metalloproteinase-2 transcriptional activation induced by p38 in breast epithelial cells.
abstract: Mounting evidence suggests a role for matrix metalloproteinase (MMP)-2 in the malignant progression of breast cancer cells. We showed previously that H-Ras, but not N-Ras, induced invasion of MCF10A human breast epithelial cells through Rac-MKK3/6-p38 pathway resulted in MMP-2 up-regulation. Activation of p38 pathway by MKK6 caused a selective up-regulation of MMP-2. In this study, we aimed to elucidate the transcriptional regulation of MMP-2 by p38 pathway leading to the invasive phenotype of MCF10A cells. By using 5' deletion mutant constructs of MMP-2 promoter, we showed that deletion of the region containing activator protein-1 (AP-1) site caused the greatest reduction of MMP-2 promoter activity both in MKK6- and H-Ras-activated MCF10A cells, suggesting that the AP-1 binding site is critical for the MMP-2 promoter activation. DNA binding and transcriptional activities of AP-1 were increased by MKK6 or H-Ras as evidenced by electrophoretic mobility shift assay and luciferase assay using an AP-1-driven plasmid. By doing immunoinhibition assay and chromatin immunoprecipitation assay, we revealed the activating transcription factor (ATF) 2 as a transcription factor for MMP-2 gene expression through binding to the functional AP-1 site. Activation of ATF2, which depended on p38 activity, was crucial for MMP-2 promoter activity as well as induction of invasive and migrative phenotypes in MCF10A cells. This is the first report revealing ATF2 as an essential transcription factor linking MKK3/6-p38 signaling pathway to MMP-2 up-regulation, providing evidence for a direct role of ATF2 activation in malignant phenotypic changes of human breast epithelial cells.
authors.affiliation: College of Pharmacy, Duksung Women's University, Seoul National University, Seoul, Korea.
authors.forename: Hyun
authors.initials: H
authors.lastname: Song
authors.forename: Sung Hwan
authors.initials: SH
authors.lastname: Ki
authors.forename: Sang Geon
authors.initials: SG
authors.lastname: Kim
authors.forename: Aree
authors.initials: A
authors.lastname: Moon
mesh_terms: D051698:Activating Transcription Factor 2 / Q000502:physiology*; D001665:Binding Sites; D001940:Breast / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D011905:Genes, ras / Q000502:physiology; D006801:Humans; D048669:MAP Kinase Kinase 6 / Q000502:physiology; D020778:Matrix Metalloproteinase 2 / Q000235:genetics*; D009361:Neoplasm Invasiveness; D018808:Transcription Factor AP-1 / Q000378:metabolism; D015533:Transcriptional Activation; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology*
chemical_list: C497105:ATF2 protein, human; D051698:Activating Transcription Factor 2; D018808:Transcription Factor AP-1; D048051:p38 Mitogen-Activated Protein Kinases; D048669:MAP Kinase Kinase 6; C482566:MAP2K6 protein, human; D020778:Matrix Metalloproteinase 2