Adrenomedullin binds with high affinity, elevates cyclic AMP, and stimulates c-fos mRNA in C6 glioma cells.
The effects of adrenomedullin (ADM) on C6 glioma cells were investigated. [125I]ADM bound with high affinity (Kd = 24 nM) to a single class of sites (Bmax = 36,000/cell) in C6 cells. Specific [125I]ADM binding was inhibited with high affinity by ADM (IC50 value of 10 nM) but not ADM(22-52) or pro-adrenomedullin N-terminal 20 peptide (PAMP). By RT-PCR, ADM receptors were detected in C6 cells. ADM elevated cAMP (ED50 value of 10 nM) whereas PAMP and ADM(22-52) did not. ADM stimulated transiently c-fos mRNA in a concentration-dependent manner. Monoclonal antibody G6, which neutralizes ADM, significantly inhibited C6 proliferation and decreased the ability of ADM to elevate c-fos mRNA. These data suggest that ADM is a regulatory peptide of C6 cells.
Moody
T W
TW
Department of Cell and Cancer Biology, National Cancer Institute, Rockville, MD 20850, USA.
Miller
M J
MJ
Mártinez
A
A
Unsworth
E
E
Cuttitta
F
F
D053607:Adrenomedullin; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D000242:Cyclic AMP / Q000378:metabolism*; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D010455:Peptides / Q000276:immunology / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis*; D012334:RNA, Neoplasm / Q000096:biosynthesis*; D051381:Rats; D058265:Receptors, Adrenomedullin; D018000:Receptors, Peptide; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D008565:Membrane Proteins; D010455:Peptides; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D058265:Receptors, Adrenomedullin; D018000:Receptors, Peptide; D053607:Adrenomedullin; D000242:Cyclic AMP