Prostanoid-induced expression of matrix metalloproteinase-1 messenger ribonucleic acid in rat osteosarcoma cells.
Individual prostanoids have distinct potencies in activating intracellular signaling pathways and regulating gene expression in osteoblastic cells. The E-series prostaglandins (PGs) are known to stimulate matrix metalloproteinase-1 (MMP-1) synthesis and secretion in certain rodent and human osteoblastic cells, yet the intracellular events involved remain unclear. To further characterize this response and its signal transduction pathway(s), we examined prostanoid-induced expression of the MMP-1 gene in the rat osteoblastic osteosarcoma cell line UMR 106-01. Northern blot analysis demonstrated that prostaglandin E2 (PGE2) and PGE1 were very potent stimulators (40-fold) of MMP-1 transcript abundance, PGF2 alpha and prostacyclin were weak stimulators (4-fold), and thromboxane-B2 had no effect. The marked increase in MMP-1 transcript abundance after PGE2 treatment was first detected at 2 h, became maximal at 4 h, and persisted beyond 24 h. This response was dose dependent and elicited maximal and half-maximal effects with concentrations of 10(-6) and 0.6 x 10(-7) M, respectively. Cycloheximide, a protein synthesis inhibitor, completely blocked this effect of PGE2, suggesting that the expression of other genes is required. Nuclear run-on experiments demonstrated that PGE2 rapidly activates MMP-1 gene transcription, with a maximal increase at 2-4 h. The second messenger analog, 8-bromo-cAMP, mimicked the effects of PGE2 by stimulating a dose-dependent increase in MMP-1 messenger RNA (mRNA) levels, with a maximal effect quantitatively similar to that observed with PGE2. Thus, in UMR 106-01 cells, different prostanoids have distinct potencies in stimulating MMP-1 mRNA abundance. Our data suggest that PGE2 stimulation of MMP-1 synthesis is due to activation of MMP-1 gene transcription and a subsequent marked increase in MMP-1 mRNA abundance. This effect is dependent on de novo protein synthesis and is mimicked by protein kinase-A activation.
Clohisy
J C
JC
Department of Pharmacological and Physiological Science, St. Louis University Health Sciences Center, Missouri 63104.
Connolly
T J
TJ
Bergman
K D
KD
Quinn
C O
CO
Partridge
N C
NC
D000818:Animals; D015152:Blotting, Northern; D001859:Bone Neoplasms / Q000737:chemistry* / Q000201:enzymology / Q000473:pathology*; D017364:Collagenases / Q000032:analysis / Q000235:genetics*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D015232:Dinoprostone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D020781:Matrix Metalloproteinase 1; D012516:Osteosarcoma / Q000737:chemistry* / Q000201:enzymology / Q000473:pathology*; D011453:Prostaglandins / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis* / Q000235:genetics; D051381:Rats; D013929:Thromboxane B2 / Q000494:pharmacology*; D013997:Time Factors; D014407:Tumor Cells, Cultured
D011453:Prostaglandins; D012333:RNA, Messenger; D013929:Thromboxane B2; D003513:Cycloheximide; D017868:Cyclic AMP-Dependent Protein Kinases; D017364:Collagenases; D020781:Matrix Metalloproteinase 1; D015232:Dinoprostone