title: TIMP-3 induces cell death by stabilizing TNF-alpha receptors on the surface of human colon carcinoma cells.
abstract: Matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) regulate the structural integrity of the extracellular matrix (ECM). Constitutive expression of human TIMP-3 in human DLD colon carcinoma cells renewed serum-responses and inhibited tumour formation in nude mice. To elucidate the mechanism of TIMP-3-mediated tumour suppression, we compared parental DLD and TIMP-3 expressing DLD cells (TIMP-3/DLD), finding them to be significantly different. TIMP-3/DLD cultures have fewer mitotic cells, are delayed in G1, and die after serum starvation. TIMP-3/DLD conditioned media activates cell death on fibroblast cells. The cell death induced by serum starvation and conditioned media was inhibited by 70%, in the presence of neutralizing tumour necrosis factor alpha (TNF-alpha) antibody. TIMP-3/DLD whole cell lysate contained p55 TNF-alpha receptor, while vector/DLD lysate had p55 TNF-alpha receptor and p46 soluble TNF-alpha inhibitor. Vector/DLD conditioned media had p46, while no soluble TNF-alpha receptor was detected in TIMP-3/DLD conditioned media. In addition, FACS analysis revealed that TIMP-3/DLD cells have more TNF-alpha surface binding sites, suggesting a direct correlation between TIMP-3 expression and surface receptors. The mechanism of tumorigenic reversion induced by TIMP-3 in DLD cells may involve protection of receptors from the proteolytic activity of MMPs. Putative TIMP-3-mediated inhibition of MMPs restores the TNF-alpha p55 signalling pathway and the carcinoma cell is killed by autocrine TNF-alpha. Thus, DLD cells have specific ECM MMPs that cleave cytokines and cytokine receptors. TIMP-3 specifically inhibits MMPs involved in receptor shedding.
authors.affiliation: Intramural Research Support Program, SAIC Frederick, National Cancer Institute, Frederick Cancer Research and Development Center, Frederick, MD 21702, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Smith
authors.forename: H
authors.initials: H
authors.lastname: Kung
authors.forename: S K
authors.initials: SK
authors.lastname: Durum
authors.forename: N H
authors.initials: NH
authors.lastname: Colburn
authors.forename: Y
authors.initials: Y
authors.lastname: Sun
mesh_terms: D015703:Antigens, CD / Q000378:metabolism*; D017209:Apoptosis; D002453:Cell Cycle; D002462:Cell Membrane / Q000378:metabolism; D003110:Colonic Neoplasms; D017077:Culture Media, Conditioned / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D016193:G1 Phase; D006801:Humans; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I; D015398:Signal Transduction; D019717:Tissue Inhibitor of Metalloproteinase-3 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014162:Transfection; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology
chemical_list: D015703:Antigens, CD; D017077:Culture Media, Conditioned; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D019717:Tissue Inhibitor of Metalloproteinase-3; D014409:Tumor Necrosis Factor-alpha