title: Human macrophage metalloelastase (MMP-12) expression is induced in chondrocytes during fetal development and malignant transformation.
abstract: Fetal development and tumor progression both require a complex system of extracellular matrix (ECM) synthesis and breakdown, which is mediated by, for instance, the matrix metalloproteinases (MMPs). Human metalloelastase (MMP-12) is an MMP, the expression of which has so far been documented in macrophages associated with atherosclerosis, wound repair, and certain cancers. In this study we first examined the expression of MMP-12 during human fetal development. By in situ hybridization MMP-12 transcripts were detected in chondrocytes of hypertrophic cartilage in vertebrae of the spinal column, in ribs, and in extremities undergoing ossification, beginning at the gestational age of 8 weeks. Also, periosteal cells expressed MMP-12 at 11 weeks. No expression of MMP-12 mRNA could be noted in other fetal tissues, including the skin, lungs, intestine, kidney, and liver. Expression of MMP-12 mRNA could not be detected in adult normal cartilage or osteosarcomas, but in chondrosarcomas both macrophages (8 of 19 samples) (identified by CD68 immunostaining) and chondrosarcoma cells (8 of 19) were positive. MMP-12 was also demonstrated in the tumors by western blotting and it was expressed in the same regions as MMP-13 mRNA. By immunostaining, MMP-12 mRNA colocalized with the protein in both fetal and chondrosarcoma specimens. Unlike basic fibroblast growth factor (bFGF) and transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha) induced MMP-12 mRNA production in chondrosarcoma-derived HTB-94 cells. Our results suggest that MMP-12 plays an important role in ECM remodeling during fetal bone development and is induced when chondrocytes undergo malignant transformation.
authors.affiliation: Department of Dermatology Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland.
authors.forename: E
authors.initials: E
authors.lastname: Kerkelä
authors.forename: T
authors.initials: T
authors.lastname: Böhling
authors.forename: R
authors.initials: R
authors.lastname: Herva
authors.forename: J A
authors.initials: JA
authors.lastname: Uria
authors.forename: U
authors.initials: U
authors.lastname: Saarialho-Kere
mesh_terms: D001859:Bone Neoplasms / Q000503:physiopathology*; D002356:Cartilage / Q000166:cytology / Q000196:embryology*; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002813:Chondrosarcoma / Q000503:physiopathology*; D017364:Collagenases / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008264:Macrophages / Q000201:enzymology; D053508:Matrix Metalloproteinase 12; D053509:Matrix Metalloproteinase 13; D008666:Metalloendopeptidases / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D017364:Collagenases; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13; D008666:Metalloendopeptidases; C507122:MMP12 protein, human; D053508:Matrix Metalloproteinase 12