Anti-TGF-beta antibody blocks enamel matrix derivative-induced upregulation of p21WAF1/cip1 and prevents its inhibition of human oral epithelial cell proliferation.
We have previously demonstrated that porcine enamel matrix derivative (EMD) contains TGF-beta 1 (or a TGF-beta-like substance), and that EMD rapidly translocates smad2, which is an effector of the TGF-beta signaling pathway, into the nucleus and modulates the proliferation of both human gingival fibroblastic and oral epithelial cells in a cell type-specific manner. To investigate the involvement of TGF-beta in the growth modulatory action of EMD, two approaches have been used in the present study: i) a neutralizing anti-TGF-beta antibody to block EMD action, and ii) authentic porcine TGF-beta 1 to compare with EMD. Both in epithelial and fibroblastic cells, TGF-beta 1 closely mimicked EMD in nuclear accumulation of smad2, phosphorylation of MAP kinase family members, and consequent cell type-specific growth modulation. Anti-TGF-beta antibody, at levels which completely blocked TGF-beta 1-induced smad2 translocation, strongly blocked EMD-induced smad2 translocation. This antibody also blocked other actions of EMD in epithelial cells, i.e. p38-MAP kinase (p38-K) phosphorylation, p21WAF1/cip1 expression, and inhibition of DNA synthesis. In support of our previous proposal, these data suggest that TGF-beta 1 (or a TGF-beta-like substance), which is delivered as a principal bioactive factor in EMD, inhibits epithelial cell proliferation probably by a smad2-mediated, p21WAF1/cip1-dependent mechanism. However, the same neutralizing antibody failed to convincingly block EMD-induced fibroblastic proliferation, which suggests that EMD may contain additional unidentified mitogenic factor(s), which act in combination with TGF-beta to fully stimulate fibroblastic proliferation.
Department of Pharmacology, Faculty of Dentistry, Niigata University, 2-5274 Gakkocho-dori, Niigata 951-8514, Japan.
Tomoyuki
T
Kawase
Kazuhiro
K
Okuda
Hiromasa
H
Yoshie
Douglas M
DM
Burns
D000704:Analysis of Variance; D000818:Animals; D000906:Antibodies / Q000276:immunology*; D002455:Cell Division / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000037:antagonists & inhibitors*; D004247:DNA / Q000037:antagonists & inhibitors; D004268:DNA-Binding Proteins / Q000032:analysis / Q000187:drug effects; D003746:Dental Enamel Proteins / Q000037:antagonists & inhibitors*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004847:Epithelial Cells / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases / Q000032:analysis / Q000037:antagonists & inhibitors; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors; D008934:Mitogens / Q000494:pharmacology; D009061:Mouth Mucosa / Q000166:cytology / Q000187:drug effects*; D010766:Phosphorylation / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D018125:Receptors, Transforming Growth Factor beta / Q000037:antagonists & inhibitors; D015398:Signal Transduction / Q000187:drug effects; D051899:Smad2 Protein; D013223:Statistics as Topic; D015534:Trans-Activators / Q000032:analysis / Q000187:drug effects; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors* / Q000276:immunology; D015854:Up-Regulation / Q000187:drug effects*; D048051:p38 Mitogen-Activated Protein Kinases
D000906:Antibodies; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004268:DNA-Binding Proteins; D003746:Dental Enamel Proteins; D004791:Enzyme Inhibitors; D008934:Mitogens; D018125:Receptors, Transforming Growth Factor beta; C497782:SMAD2 protein, human; D051899:Smad2 Protein; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; C109069:enamel matrix proteins; D004247:DNA; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases