title: PP2B and ERK1/2 regulate hyaluronan synthesis of HT168 and WM35 human melanoma cell lines.
abstract: Hyaluronan (HA) is the major glycosaminoglycan component of the extracellular matrix in either normal or malignant tissues and it may affect proliferation, motility and differentiation of various cell types. Three isoforms of plasma membrane-bound hyaluronan synthases (HAS 1, 2 and 3) secrete and simultaneously bind pericellular HA. HAS enzymes are subjects of post-translational protein phosphorylation which is believed to regulate their enzymatic activity. In this study, we investigated the HA homeostasis of normal human epidermal melanocytes, HT168 and WM35 human melanoma cell lines and melanoma metastases. HAS2 and HAS3 were detected in all the samples, while the expression of HAS1 was not detectable in any case. Malignant tissue samples and melanoma cell lines contained extra- and intracellular HA abundantly but not normal melanocytes. Applying HA as a chemoattractant facilitated the migration of melanoma cells in Boyden chamber. The amount of HA was reduced upon the inhibition of calcineurin with cyclosporine A (CsA), while the inhibition of ERK1/2 with PD098059 elevated it in both cell lines. The signals of Ser/Thr phosphoproteins at 57 kD were stronger after CsA treatment, while a markedly weaker signal was detected upon inhibition of the MAPK pathway. Our results suggest opposing effects of the two investigated enzymes on the HA homeostasis of melanoma cells. We propose that the dephosphorylation of HAS enzymes targeted by PP2B augments HA production, while their phosphorylation by the activity of MAPK pathway reduces HA synthesis. As the expression of the HA receptor RHAMM was also significantly enhanced by PD098059, the MAPK pathway exerted a complex attenuating effect on HA signalling in the investigated melanoma cells. This observation suggests that the application of MAPK-ERK pathway inhibitors requires a careful therapeutic design in melanoma treatment.
authors.affiliation: Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary.
authors.forename: Éva
authors.initials: É
authors.lastname: Katona
authors.affiliation: Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Juhász
authors.affiliation: Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary.
authors.forename: Csilla Szűcs
authors.initials: CS
authors.lastname: Somogyi
authors.affiliation: Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary.
authors.forename: Tibor
authors.initials: T
authors.lastname: Hajdú
authors.affiliation: Department of Pathology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary.
authors.forename: Csaba
authors.initials: C
authors.lastname: Szász
authors.affiliation: Department of Forensic Medicine, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary.
authors.forename: Kálmán
authors.initials: K
authors.lastname: Rácz
authors.affiliation: Department of Cell Biology and Signalling Research Group of the Hungarian Academy of Sciences, Department of Medical Chemistry, Research Centre for Molecular Medicine, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary.
authors.forename: Endre
authors.initials: E
authors.lastname: Kókai
authors.affiliation: Department of Cell Biology and Signalling Research Group of the Hungarian Academy of Sciences, Department of Medical Chemistry, Research Centre for Molecular Medicine, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary.
authors.forename: Pál
authors.initials: P
authors.lastname: Gergely
authors.affiliation: Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Debrecen, H-4032 Debrecen, Hungary.
authors.forename: Róza
authors.initials: R
authors.lastname: Zákány
mesh_terms: D019703:Calcineurin / Q000378:metabolism; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D016572:Cyclosporine / Q000737:chemistry; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005419:Flavonoids / Q000737:chemistry; D015972:Gene Expression Regulation, Neoplastic; D014453:Glucuronosyltransferase / Q000378:metabolism; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid / Q000096:biosynthesis*; D020935:MAP Kinase Signaling System; D008545:Melanoma / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D054648:Protein Phosphatase 2 / Q000378:metabolism*
chemical_list: D005419:Flavonoids; D018960:Hyaluronan Receptors; D010750:Phosphoproteins; D016572:Cyclosporine; D006820:Hyaluronic Acid; D014453:Glucuronosyltransferase; D000076002:Hyaluronan Synthases; D048049:Extracellular Signal-Regulated MAP Kinases; D019703:Calcineurin; D054648:Protein Phosphatase 2; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one