Premium
Regulation of plasminogen activation, matrix metalloproteinases and urokinase‐type plasminogen activator‐mediated extracellular matrix degradation in human osteosarcoma cell line MG63 by interleukin‐1 alpha
Author(s) -
de Bart Anton C. W.,
Quax Paul H.A.,
Löwik Clemens W.G.M.,
Verheijen Jan H.
Publication year - 1995
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1002/jbmr.5650100915
Subject(s) - plasminogen activator , extracellular matrix , matrix metalloproteinase , urokinase receptor , urokinase , cytokine , microbiology and biotechnology , extracellular , plasmin , endocrinology , cell culture , chemistry , medicine , biology , biochemistry , enzyme , genetics
Abstract Plasmin‐mediated extracellular proteolysis has been implicated in the degradation of bone in normal and pathological conditions. Normal and malignant osteoblasts can produce both tissue‐type plasminogen activator (t‐PA) and urokinase‐type plasminogen activator (u‐PA). We have used the osteosarcoma cell line MG63 to address the question of whether the enhanced bone turnover in osteosarcomas is mediated by t‐PA or by u‐PA and to study the effect of the cytokine interleukin‐1α (IL‐1α), known to influence bone degradation, on the plasminogen activator production and extracellular matrix degradation in malignant osteoblastic cells. Furthermore, the effect of IL‐1α on the synthesis of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) was analyzed. u‐PA production by MG63 was high (approximately 180 ng/10 6 cells/24 h). Also t‐PA and PAI‐1 production was observed. u‐PA production was rapidly increased in MG63 by IL‐1α (10 ng/ml), whereas an effect on t‐PA production was only found after a prolonged incubation and hardly any effect of IL‐1α on PAI‐1 production was observed. mRNA analysis revealed similar effects. u‐PA receptor (u‐PAR) mRNA was detectable in MG63 cells and could be increased by IL‐1α after 24 h. In MG63, u‐PA‐mediated extracellular matrix degradation was detectable, and IL‐1α increased the u‐PA‐mediated matrix degradation (approximately 2‐fold). Under control conditions in MG63, only MMP‐2, TIMP‐1, and TIMP‐2 mRNA could be observed. After the addition of IL‐1α, a very rapid increase in MMP‐1 and MMP‐3 mRNA could be observed as well as a moderate increase in TIMP‐1 mRNA. The presence of MMP‐2 was demonstrated by gelatin zymography. These results show that IL‐1α can stimulate u‐PA production and can regulate extracellular proteolytic activity mainly via u‐PA induction in the MG63 osteosarcoma cell line. Furthermore, IL‐1α has a strong stimulating effect on the production of MMP‐1 and MMP‐3. These findings suggest that u‐PA and possibly MMP‐1 and MMP‐3 play an important role in the process of bone turnover in osteosarcomas.