Effects of 17beta-estradiol on the expression of membrane type 1 matrix metalloproteinase (MT1-MMP) and MMP-2 in human osteoblastic MG-63 cell cultures.
Estrogens are important regulators of bone cell function. Osteoblast-derived membrane type 1 matrix metalloproteinses (MT1-MMP) have recently been implied to play an important role in the process of bone resorption by proteolytically activating latent matrix metalloproteinase-2 (proMMP-2) at the cell surface and degrading tumor necrosis factor-alpha (TNF-alpha). In the present study, we observed the effects of 17beta-estradiol (E2) on MT1-MMP production and subsequent activation of latent matrix proMMP-2, and also proMMP-2 secretion in cultures of human osteoblastic MG-63 cells. Western immunoblot analysis showed that treatment with increasing doses of E2 in MG-63 cells caused a dose-dependent increase in expression of MT1-MMP protein. Confocal immunohistochemistry analysis also confirmed that E2 induced MT1-MMP synthesis in MG-63 cells. We found unexpectedly that although MT1-MMP synthesis was up-regulated by E2 in cultures of MG-63 cells, activation of proMMP-2 was unchanged, which can be attributed partly to the undetectable tissue inhibitor of metalloproteinase-2 (TIMP-2) protein in MG-63 cells by Western immunoblotting. ProMMP-2 production was also not influenced by E2. In conclusion, E2 induces MT1-MMP protein expression in MG-63 cells while it is not followed by proMMP-2 activation, E2 may suppress bone resorption by accentuated degradation of TNF-alpha which mediated through increasingly MT1 -MMP production in osteoblastic cells.
Liao
E Y
EY
Institute of Endocrinology and Metabolism, The Second Affiliated Hospital, Hunan Medical University, Changsha, PR China.
Luo
X H
XH
Deng
X G
XG
Wu
X P
XP
D015153:Blotting, Western; D002460:Cell Line; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D018093:Gelatinases / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000378:metabolism*; D010006:Osteoblasts / Q000187:drug effects* / Q000201:enzymology*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000096:biosynthesis
D004792:Enzyme Precursors; D019716:Tissue Inhibitor of Metalloproteinase-2; D004958:Estradiol; D018093:Gelatinases; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; C069860:progelatinase; D020778:Matrix Metalloproteinase 2