title: Density- and proliferation status-dependent expression of T-cadherin, a novel lipoprotein-binding glycoprotein: a function in negative regulation of smooth muscle cell growth?
abstract: The atypical low density lipoprotein (LDL) binding proteins (Mr 105 and 130 kDa; p105 and p130) in human aortic medial membranes and cultured human and rat aortic smooth muscle cells (SMC) have recently been identified as the cell adhesion glycoprotein T-cadherin. Although cadherins are generally recognized to be important regulators of morphogenesis, the function of T-cadherin in the vasculature is poorly understood. This study has examined the relationship between expression of T-cadherin and the density and proliferation status of SMC. T-cadherin (p105 and p130) levels in SMC lysates were measured on Western blots using ligand-binding techniques. T-cadherin expression was dependent upon cell density, and maximal levels were achieved at confluency. T-cadherin levels were reversibly modulated by switching cultures between serum-free (upmodulation) and serum-containing (downmodulation) conditions. Platelet-derived growth factor (PDGF)-BB, epidermal growth factor (EGF) or insulin-like growth factor (IGF) elicited a dose- and time-dependent downmodulation that was reversible after transfer of SMC to growth factor-free medium. Our results support the hypothesis that T-cadherin may function as a negative determinant of cell growth.
authors.affiliation: Department of Research, Basel University Hospital, Switzerland.
authors.forename: Y S
authors.initials: YS
authors.lastname: Kuzmenko
authors.forename: F
authors.initials: F
authors.lastname: Kern
authors.forename: V N
authors.initials: VN
authors.lastname: Bochkov
authors.forename: V A
authors.initials: VA
authors.lastname: Tkachuk
authors.forename: T J
authors.initials: TJ
authors.lastname: Resink
mesh_terms: D000818:Animals; D015820:Cadherins / Q000096:biosynthesis*; D002452:Cell Count; D002455:Cell Division; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D006023:Glycoproteins / Q000096:biosynthesis*; D006801:Humans; D008074:Lipoproteins / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D051381:Rats
chemical_list: D015820:Cadherins; D016895:Culture Media, Serum-Free; D006023:Glycoproteins; C099972:H-cadherin; D008074:Lipoproteins