Parathyroid hormone responses of cyclic AMP-, serum- and phorbol ester-responsive reporter genes in osteoblast-like UMR-106 cells.
Parathyroid hormone (PTH) and PTH-related protein interact with a G protein-coupled receptor linked to the activation of adenylyl cyclase and phospholipase C signaling pathways. Regulation by PTH of the expression of three distinct, stably transfected luciferase reporter genes responsive to cAMP (CRE-luc), serum (SRE-luc) and phorbol ester (TRE-luc) has been studied in rat osteoblast-like UMR-106 cells. Maximal 43-fold induction of CRE-luc expression occurred in response to 100 nM rat (r)PTH(1-34) (EC50=0.44 nM), but SRE-luc and TRE-luc remained unaffected. Maximal 2.8- and 3.4-fold inductions of SRE-luc by 10 ng/ml EGF and 100 nM phorbol ester (PMA) were suppressed with 100 nM rPTH(1-34) (IC50=0.04 and 0.15 nM, respectively). Similarly, 7.3-fold induction of TRE-luc by 100 nM PMA was inhibited to 50% with 100 nM rPTH(1-34) (IC50=0.5 nM). Activation of mitogen-activated protein kinase by EGF and PMA was also suppressed by rPTH(1-34). 1 mM 8-Br-cAMP and 0.1 mM forskolin mimicked all the effects of rPTH(1-34). In conclusion, the regulation of target genes by PTH in osteoblast-like UMR-106 cells is mediated by the activation of the cAMP/protein kinase A signaling pathway.
Research Laboratory for Calcium Metabolism, Department of Orthopedic Surgery, Zurich, Switzerland.
B
B
Flühmann
U
U
Zimmermann
R
R
Muff
G
G
Bilbe
J A
JA
Fischer
W
W
Born
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D001769:Blood; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000502:physiology*; D017930:Genes, Reporter / Q000235:genetics*; D008156:Luciferases / Q000235:genetics; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D008969:Molecular Sequence Data; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000494:pharmacology*; D051381:Rats; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection
D010281:Parathyroid Hormone; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D004815:Epidermal Growth Factor; D000242:Cyclic AMP; D008156:Luciferases; D017868:Cyclic AMP-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D013755:Tetradecanoylphorbol Acetate