title: Axl promotes cell invasion by inducing MMP-9 activity through activation of NF-kappaB and Brg-1.
abstract: Activity of the Axl receptor tyrosine kinase is positively correlated with tumor metastasis; however, its detailed role in the mechanism of tumor invasion is still not completely understood. Here, we show that Axl enhances the expression of matrix metalloproteinase 9 (MMP-9), required for Axl-mediated invasion both in vitro and in vivo. We found that the highly selective MEK1/2 inhibitors U0126 and PD98059, and the expressed dominant-negative form of extracellular signal-regulated kinase (ERK), completely block Axl-mediated MMP-9 activation. In contrast, the phosphatidylinositol 3-kinase inhibitor LY294002 and wortmannin had little effect on activation. Interestingly, however, the Axl ligand Gas6 is not involved in Axl-mediated MMP-9 activation. Mutation of Glu59(Axl) and Thr77(Axl) dramatically reduced Gas6-Axl binding but continued to induce MMP-9 activation. In addition, overexpression of Axl-activated ERK and enhanced nuclear factor-kappaB (NF-kappaB) transactivation and brahma-related gene-1 (Brg-1) translocation. Exposure to the NF-kappaB inhibitor silibinin, which inhibits IkappaBalpha kinase activity, or overexpression of the dominant-negative mutant IkappaB and Brg-1 strikingly inhibited Axl-mediated MMP-9 activation. These data indicate that coordination of ERK signaling and NF-kappaB and Brg-1 activation are indispensable to regulation of Axl-dependent MMP-9 gene transcription. Together with previous data, our results provide a plausible mechanism for Axl-mediated tumor invasion and establish a functional link between the Axl and MMP-9 signaling pathways.
authors.affiliation: Institute of Cancer Research, National Health Research Institutes, Miaoli County, Taiwan.
authors.forename: K-Y
authors.initials: KY
authors.lastname: Tai
authors.forename: Y-S
authors.initials: YS
authors.lastname: Shieh
authors.forename: C-S
authors.initials: CS
authors.lastname: Lee
authors.forename: S-G
authors.initials: SG
authors.lastname: Shiah
authors.forename: C-W
authors.initials: CW
authors.lastname: Wu
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000235:genetics; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism*; D004790:Enzyme Induction / Q000187:drug effects / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D051550:I-kappa B Kinase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D048370:MAP Kinase Kinase 2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000235:genetics; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis* / Q000235:genetics; D009154:Mutation; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011485:Protein Binding / Q000187:drug effects / Q000235:genetics; D011518:Proto-Oncogene Proteins; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics; D000094963:Axl Receptor Tyrosine Kinase; D000099255:Growth Arrest-Specific Protein 6
chemical_list: D004265:DNA Helicases; D004791:Enzyme Inhibitors; D051550:I-kappa B Kinase; D036341:Intercellular Signaling Peptides and Proteins; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D020780:Matrix Metalloproteinase 9; D016328:NF-kappa B; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011518:Proto-Oncogene Proteins; D020794:Receptor Protein-Tyrosine Kinases; D014157:Transcription Factors; D000094963:Axl Receptor Tyrosine Kinase; D000099255:Growth Arrest-Specific Protein 6; C482128:MAP2K2 protein, human; C482125:MAP2K1 protein, human; C084108:SMARCA4 protein, human; C000722289:AXL protein, human