title: Ras, protein kinase C zeta, and I kappa B kinases 1 and 2 are downstream effectors of CD44 during the activation of NF-kappa B by hyaluronic acid fragments in T-24 carcinoma cells.
abstract: We have investigated the ability of hyaluronic acid (HA) fragments to activate the transcription factor NF-kappa B. HA fragments activated NF-kappa B in the cell lines T-24, HeLa, MCF7, and J774. Further studies in T-24 cells demonstrated that HA fragments also induced I kappa B alpha phosphorylation and degradation, kappa B-linked reporter gene expression, and ICAM-1 promoter activity in an NF-kappa B-dependent manner. The effect of HA was size dependent as neither disaccharide nor native HA were active. CD44, the principal cellular receptor for HA, was critical for the response because the anti-CD44 Ab IM7.8.1 blocked the effect on NF-kappa B. HA fragments activated the I kappa B kinase complex, and the effect on a kappa B-linked reporter gene was blocked in T-24 cells expressing dominant negative I kappa B kinases 1 or 2. Activation of protein kinase C (PKC) was required because calphostin C inhibited NF-kappa B activation and I kappa B alpha phosphorylation. In particular, PKC zeta was required because transfection of cells with dominant negative PKC zeta blocked the effect of HA fragments on kappa B-linked gene expression and HA fragments increased PKC zeta activity. Furthermore, damnacanthal and manumycin A, two mechanistically distinct inhibitors of Ras, blocked NF-kappa B activation. Transfection of T-24 cells with dominant negative Ras (RasN17) blocked HA fragment-induced kappa B-linked reporter gene expression, and HA fragments activated Ras activity within 5 min. Taken together, these studies establish a novel signal transduction cascade emanating from CD44 to Ras, PKC zeta, and I kappa B kinase 1 and 2.
authors.affiliation: Department of Biochemistry, Trinity College, Dublin, Ireland.
authors.forename: K A
authors.initials: KA
authors.lastname: Fitzgerald
authors.forename: A G
authors.initials: AG
authors.lastname: Bowie
authors.forename: B S
authors.initials: BS
authors.lastname: Skeffington
authors.forename: L A
authors.initials: LA
authors.lastname: O'Neill
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000378:metabolism; D004306:Dose-Response Relationship, Immunologic; D015972:Gene Expression Regulation, Neoplastic / Q000276:immunology; D017930:Genes, Reporter / Q000276:immunology; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000737:chemistry / Q000494:pharmacology*; D051550:I-kappa B Kinase; D020672:I-kappa B Proteins; D007527:Isoenzymes / Q000502:physiology; D051379:Mice; D008970:Molecular Weight; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D014407:Tumor Cells, Cultured; D001749:Urinary Bladder Neoplasms / Q000201:enzymology / Q000378:metabolism*; D018631:ras Proteins / Q000502:physiology*; D000099221:Protein Kinase C zeta
chemical_list: D004268:DNA-Binding Proteins; D018960:Hyaluronan Receptors; D006820:Hyaluronic Acid; D051550:I-kappa B Kinase; D020672:I-kappa B Proteins; D007527:Isoenzymes; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B; D011493:Protein Kinase C; D017346:Protein Serine-Threonine Kinases; D018631:ras Proteins; D000099221:Protein Kinase C zeta; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; C496559:CHUK protein, human; C496564:Chuk protein, mouse; C496560:IKBKB protein, human; C496565:IKBKE protein, human; C496562:Ikbkb protein, mouse; C496566:Ikbke protein, mouse