title: Blockade of tumor growth due to matrix metalloproteinase-9 inhibition is mediated by sequential activation of beta1-integrin, ERK, and NF-kappaB.
abstract: We previously showed that matrix metalloproteinase (MMP)-9 inhibition using an adenovirus-mediated delivery of MMP-9 small interfering RNA (Ad-MMP-9), caused senescence in medulloblastoma cells. Regardless of whether or not Ad-MMP-9 would induce apoptosis, the possible signaling mechanism is still obscure. In this report, we demonstrate that Ad-MMP-9 induced apoptosis in DAOY cells as determined by propidium iodide and terminal deoxynucleotidyltransferase-mediated nick end labeling staining. Ad-MMP-9 infection induced the release of cytochrome c, activation of caspase-9 and -3, and cleavage of poly(ADP-ribose) polymerase. Ad-MMP-9 infection stimulated ERK, and electrophoretic mobility shift assay indicated an increase in NF-kappaB activation. ERK inhibition, using a kinase-dead mutant for ERK, ameliorated NF-kappaB activation and caspase-mediated apoptosis in Ad-MMP-9-infected cells. beta1-Integrin expression in Ad-MMP-9-infected cells also increased, and this increase was reversed by the reintroduction of MMP-9. We found that the addition of beta1 blocking antibodies inhibited Ad-MMP-9-induced ERK activation. Taken together, our results indicate that MMP-9 inhibition induces apoptosis due to altered beta1-integrin expression in medulloblastoma. In addition, ERK activation plays an active role in this process and functions upstream of NF-kappaB activation to initiate the apoptotic signal.
authors.affiliation: Program of Cancer Biology, Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois 61605.
authors.forename: Praveen
authors.initials: P
authors.lastname: Bhoopathi
authors.affiliation: Program of Cancer Biology, Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois 61605.
authors.forename: Chandramu
authors.initials: C
authors.lastname: Chetty
authors.affiliation: Program of Cancer Biology, Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois 61605.
authors.forename: Sateesh
authors.initials: S
authors.lastname: Kunigal
authors.affiliation: Program of Cancer Biology, Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois 61605.
authors.forename: Sravan K
authors.initials: SK
authors.lastname: Vanamala
authors.affiliation: Program of Cancer Biology, Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois 61605; Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, Illinois 61605.
authors.forename: Jasti S
authors.initials: JS
authors.lastname: Rao
authors.affiliation: Program of Cancer Biology, Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois 61605. Electronic address: slakka@uic.edu.
authors.forename: Sajani S
authors.initials: SS
authors.lastname: Lakka
mesh_terms: D000256:Adenoviridae; D000818:Animals; D017209:Apoptosis; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005799:Genes, Dominant; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D019012:Integrin beta1 / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D061965:Matrix Metalloproteinase Inhibitors; D008527:Medulloblastoma / Q000201:enzymology / Q000473:pathology; D051379:Mice; D008954:Models, Biological; D016328:NF-kappa B / Q000378:metabolism*; D009369:Neoplasms / Q000201:enzymology* / Q000473:pathology*; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D014162:Transfection
chemical_list: D020672:I-kappa B Proteins; D019012:Integrin beta1; D061965:Matrix Metalloproteinase Inhibitors; D016328:NF-kappa B; D048049:Extracellular Signal-Regulated MAP Kinases