Regulation of gene transcription and proliferation by parathyroid hormone is blocked in mutant osteoblastic cells resistant to cyclic AMP.
We employed a cyclic AMP-resistant subclone of UMR 106-01 osteoblastic osteosarcoma cells (UMR 4-7) with a regulated, dominant-negative mutation of cyclic AMP-dependent protein kinase (PK-A), to examine the mechanism(s) whereby parathyroid hormone (PTH) regulates growth of these cells. Expression of a transiently transfected CAT reporter gene controlled by the cAMP response element of the rat somatostatin gene ('SST-CAT') was used to monitor PK-A activation in intact cells. Agonist-stimulated SST-CAT expression was specific for agents known to activate adenylate cyclase, required an intact cAMP response element and was specifically blocked following induction of the mutant cAMP-resistant phenotype in UMR 4-7 cells. Inhibition of the proliferation of UMR 106-01 cells by PTH, which is mimicked by forskolin and 8-bromo-cAMP, was blocked completely in mutant cyclic AMP-resistant UMR 4-7 cells. We conclude that control of proliferation in UMR 106-01 cells by PTH involves the cAMP messenger system and requires activation of PK-A.
Zajac
J D
JD
Endocrine Unit, Massachusetts General Hospital, Boston 02114.
Kearns
A K
AK
Skurat
R M
RM
Kronenberg
H M
HM
Bringhurst
F R
FR
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D001859:Bone Neoplasms / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D002455:Cell Division / Q000187:drug effects; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology / Q000502:physiology*; D004789:Enzyme Activation / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006133:Growth Substances / Q000494:pharmacology; D008969:Molecular Sequence Data; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects*; D012516:Osteosarcoma / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D010281:Parathyroid Hormone / Q000494:pharmacology*; D011453:Prostaglandins / Q000494:pharmacology; D011494:Protein Kinases / Q000235:genetics* / Q000502:physiology; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D013004:Somatostatin / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects*; D014407:Tumor Cells, Cultured
D006133:Growth Substances; D010281:Parathyroid Hormone; D011453:Prostaglandins; D011993:Recombinant Fusion Proteins; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D013004:Somatostatin; D000242:Cyclic AMP; D011494:Protein Kinases; D000262:Adenylyl Cyclases