Tetraspanin CD9 induces MMP-2 expression by activating p38 MAPK, JNK and c-Jun pathways in human melanoma cells.
Expression of matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9), which correlates with tumor invasion and metastasis, has been known to be regulated by several intracellular signaling pathways. Since the CD9 membrane protein has been implicated in signal transduction and malignant progression of cancer cells, we examined the functional involvement of CD9 in the regulation of MMP-2 and MMP-9 expression by using stable CD9 transfectant clones of MelJuso human melanoma cells. The CD9 cDNA-transfected cells with elevated CD9 expression displayed increased MMP-2 and decreased MMP-9 expression when compared with the mock transfectant cells. Among several signal pathway inhibitors tested, SB203580 and SP600125, which inhibit p38 MAPK and JNK respectively, completely blocked the CD9-stimulated MMP-2 expression. Phosphorylation levels of p38 MAPK and c-Jun in MelJuso cells were also significantly increased by CD9 transfection. In addition, the down-regulation of p38 MAPK and JNK by siRNA transfection resulted in a decrease in MMP-2 expression by MelJuso cells. Promoter analysis and gel shift assay showed that the CD9-induced MMP-2 expression is mediated by a functional AP-1 site through interactions with AP-1 transcription factors including c-Jun. These results suggest that CD9 induces MMP-2 expression by activating c- Jun through p38 MAPK and JNK signaling pathways in human melanoma cells.
Hong
In-Kee
IK
Vascular System Research Center and Division of Life Sciences, College of Natural Sciences, School of Medicine, Kangwon National University, Chunchon 200-701, Republic of Korea.
Kim
Young-Myeong
YM
Jeoung
Doo-Il
DI
Kim
Keun-Cheol
KC
Lee
Hansoo
H
D015703:Antigens, CD / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D004789:Enzyme Activation; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D008562:Membrane Glycoproteins / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology; D015398:Signal Transduction; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology; D060245:Tetraspanin 29; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
D015703:Antigens, CD; C554869:CD9 protein, human; D008562:Membrane Glycoproteins; D016755:Proto-Oncogene Proteins c-jun; D034741:RNA, Small Interfering; D060245:Tetraspanin 29; D018808:Transcription Factor AP-1; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9