title: The role of TG2 in regulating S100A4-mediated mammary tumour cell migration.
abstract: The importance of S100A4, a Ca(2+)-binding protein, in mediating tumour cell migration, both intracellularly and extracellularly, is well documented. Tissue transglutaminase (TG2) a Ca(2+)-dependent protein crosslinking enzyme, has also been shown to enhance cell migration. Here by using the well characterised non-metastatic rat mammary R37 cells (transfected with empty vector) and highly metastatic KP1 cells (R37 cells transfected with S100A4), we demonstrate that inhibition of TG2 either by TG2 inhibitors or transfection of cells with TG2 shRNA block S100A4-accelerated cell migration in the KP1cells and in R37 cells treated with exogenous S100A4. Cell migration was also blocked by the treatment with the non-cell permeabilizing TG2 inhibitor R294, in the human breast cancer cell line MDA-MB-231 (Clone 16, which has a high level of TG2 expression). Inhibition was paralleled by a decrease in S100A4 polymer formation. In vitro co-immunoprecipitation and Far Western blotting assays and cross-linking assays showed not only the direct interaction between TG2 and S100A4, but also confirmed S100A4 as a substrate for TG2. Using specific functional blocking antibodies, a targeting peptide and a recombinant protein as a competitive treatment, we revealed the involvement of syndecan-4 and α5β1 integrin co-signalling pathways linked by activation of PKCα in this TG2 and S100A4-mediated cell migration. We propose a mechanism for TG2-regulated S100A4-related mediated cell migration, which is dependent on TG2 crosslinking.
authors.affiliation: School of Life and Health Sciences, Aston University, Aston Triangle, Birmingham, United Kingdom.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Wang
authors.forename: Martin
authors.initials: M
authors.lastname: Griffin
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002464:Cell Migration Inhibition / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D039081:Integrin alpha5beta1 / Q000235:genetics / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D015674:Mammary Neoplasms, Animal / Q000235:genetics* / Q000378:metabolism; D010455:Peptides / Q000494:pharmacology; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D051571:Protein Kinase C-alpha / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D053671:Syndecan-4 / Q000235:genetics / Q000378:metabolism; D011503:Transglutaminases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D039081:Integrin alpha5beta1; D007527:Isoenzymes; D010455:Peptides; D034741:RNA, Small Interfering; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins; C499412:S100a4 protein, rat; C508307:Sdc4 protein, rat; D053671:Syndecan-4; C000717609:Tgm2 protein, rat; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D051571:Protein Kinase C-alpha; D019204:GTP-Binding Proteins