title: Regulation of MMP-9 (92 kDa type IV collagenase/gelatinase B) expression in stromal cells of human giant cell tumor of bone.
abstract: Matrix metalloproteinases (MMPs) play an important regulatory role in tissue morphogenesis, cell differentiation, tumor invasion and metastasis. Several authors have reported a direct correlation between the production of 72 kDa (MMP-2) and 92 kDa (MMP-9) type IV collagenases/gelatinases and the metastatic potential of cancer cells. Recently, we have identified the expression of both MMP-2 and MMP-9 in primary cultures of human giant cell tumor (GCT) of bone in vitro, and in tissue extracts in vivo. Interestingly, MMP-9 is not secreted by late-passaged GCT cells. It is possible that the production of MMP-9 is regulated by certain factor(s) secreted by the multinucleated giant cells in the primary culture. In order to test this hypothesis, the effect of primary-culture-conditioned medium on the expression of MMP-9 by late-passaged mononuclear stromal cells was examined. Adding conditioned medium from the primary GCT culture to the late-passaged stromal cells induced MMP-9, as evidenced by the presence of lytic bands at M(r) 92,000 and 72,000 on a gelatin zymogram. These enzyme activities were inhibited by EDTA, a well-known inhibitor of the MMPs. We confirmed these results by Western blotting using specific antibodies and RT-PCR for MMP-2 and MMP-9. Immunofluorescence studies with specific antibodies to MMP-9 further confirmed its expression by the passaged stromal cells cultured in the primary-culture-conditioned medium. The data indicate that MMP-2 and MMP-9 are produced by the mononuclear stromal cells when cultured in GCT primary-culture-conditioned medium. This suggests that multinucleated giant cells in primary cultures secrete a factor(s) that stimulates stromal cells to produce MMP-9, which, in turn, may contribute to the aggressive behavior of GCT.
authors.affiliation: Meyer Rehabilitation Institute and Department of Pediatrics, University of Nebraska Medical Center, Omaha 68198, USA. VRAO@UNMC.EDU
authors.forename: V H
authors.initials: VH
authors.lastname: Rao
authors.forename: R K
authors.initials: RK
authors.lastname: Singh
authors.forename: J A
authors.initials: JA
authors.lastname: Bridge
authors.forename: J R
authors.initials: JR
authors.lastname: Neff
authors.forename: G B
authors.initials: GB
authors.lastname: Schaefer
authors.forename: D C
authors.initials: DC
authors.lastname: Delimont
authors.forename: C M
authors.initials: CM
authors.lastname: Dunn
authors.forename: W G
authors.initials: WG
authors.lastname: Sanger
authors.forename: B A
authors.initials: BA
authors.lastname: Buehler
authors.forename: R
authors.initials: R
authors.lastname: Sawaya
authors.forename: G L
authors.initials: GL
authors.lastname: Nicolson
authors.forename: J S
authors.initials: JS
authors.lastname: Rao
mesh_terms: D000293:Adolescent; D015153:Blotting, Western; D001859:Bone Neoplasms / Q000201:enzymology* / Q000473:pathology; D017364:Collagenases / Q000235:genetics / Q000378:metabolism*; D017077:Culture Media, Conditioned; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018212:Giant Cell Tumor of Bone / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008297:Male; D020780:Matrix Metalloproteinase 9; D008875:Middle Aged; D017154:Stromal Cells / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D017077:Culture Media, Conditioned; D017364:Collagenases; D020780:Matrix Metalloproteinase 9