title: Upregulation of matrix metalloproteinase-9 in murine 5T33 multiple myeloma cells by interaction with bone marrow endothelial cells.
abstract: MM is a B-cell malignancy mainly characterized by monoclonal expansion of plasma cells in the BM, presence of paraprotein in serum and occurrence of osteolytic bone lesions. MMPs are a family of proteolytic enzymes that can contribute to cancer growth, invasion, angiogenesis, bone degradation and other processes important in the pathogenesis of MM. We investigated MMP-9 production in the 5T33MM murine model. Expression of MMP-9 protein in supernatant and cell extracts was analyzed by gelatin zymography. The in vitro, stroma-independent variant 5T33MMvt showed no protein expression of MMP-9 in contrast to in vivo growing MM cells, 5T33MMvv. However, when 5T33MMvt cells were injected into naive mice and isolated after tumor take (5T33MMvt-vv), they secreted a significant amount of MMP-9. These results were confirmed by specific staining of cytospins with an anti-MMP-9 antibody. The MMP-9 production by 5T33MMvt-vv cells disappeared when the cells were recultured in vitro. These data demonstrated that upregulation of MMP-9 occurs in vivo and that this process is dependent on the microenvironment. Cocultures of 5T33MMvt cells with STR10 BMECs induced MMP-9 in MM cells, as determined by both gelatin zymography and flow-cytometric analysis. In conclusion, our results demonstrate that MMP-9 production by MM cells is upregulated in vivo by the interaction of MM cells with BMECs.
authors.affiliation: Department of Hematology and Immunology, Free University Brussels, Brussels, Belgium.
authors.forename: Els
authors.initials: E
authors.lastname: Van Valckenborgh
authors.forename: Marleen
authors.initials: M
authors.lastname: Bakkus
authors.forename: Carine
authors.initials: C
authors.lastname: Munaut
authors.forename: Agnes
authors.initials: A
authors.lastname: Noël
authors.forename: Yves
authors.initials: Y
authors.lastname: St  Pierre
authors.forename: Kewal
authors.initials: K
authors.lastname: Asosingh
authors.forename: Ivan
authors.initials: I
authors.lastname: Van Riet
authors.forename: Ben
authors.initials: B
authors.lastname: Van Camp
authors.forename: Karen
authors.initials: K
authors.lastname: Vanderkerken
mesh_terms: D000818:Animals; D001685:Biological Factors / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism*; D002448:Cell Adhesion; D004727:Endothelium / Q000166:cytology / Q000378:metabolism*; D004790:Enzyme Induction; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009101:Multiple Myeloma / Q000201:enzymology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured; D015854:Up-Regulation
chemical_list: D001685:Biological Factors; D012333:RNA, Messenger; D020780:Matrix Metalloproteinase 9