title: Exchange proteins directly activated by cAMP induce the proliferation of rat anterior pituitary GH3 cells via the activation of extracellular signal-regulated kinase.
abstract: Cyclic adenosine 3'-5'-monophosphate (cAMP) plays a crucial role in regulating pituitary cell proliferation and hormone synthesis. Recent evidence suggests that exchange proteins directly activated by cAMP (Epacs) may mediate the effects of cAMP. Here we used rat anterior pituitary GH3 cells as the experiment model to demonstrate that forskolin increased the proliferation of GH3 cells and the phosphorylation of ERK1/2, and these effects were inhibited by PKA or Epac inhibitors. Epac activator 8-pCPT-2'-O-Me-cAMP increased GH3 cell proliferation and this was blocked by ESI-09, an Epac inhibitor. In contrast, forskolin-induced phosphorylation of CREB was unaffected by Epac inhibition. Notably, increased phosphorylation of ERK1/2 was correlated with increased cyclin D3 expression in GH3 cells. Furthermore, knockdown of Epac as well as B-Raf and MEK inhibitors blocked 8-pCPT-2'-O-Me-cAMP induced proliferation of GH3 cells and the phosphorylation of ERK1/2. In conclusion, our study suggests that Epac mediates cAMP induced pituitary cell proliferation via B-Raf and MAPK dependent mechanism.
authors.affiliation: Department of Neurosurgery, Sino-German Neuro-Oncology Molecular Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
authors.affiliation: Department of Neurosurgery, Sino-German Neuro-Oncology Molecular Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Jiao
authors.affiliation: Department of Neurosurgery, Sino-German Neuro-Oncology Molecular Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Neurosurgery, Sino-German Neuro-Oncology Molecular Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China.
authors.forename: Ran
authors.initials: R
authors.lastname: Li
authors.affiliation: Department of Neurosurgery, Sino-German Neuro-Oncology Molecular Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China.
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Neurosurgery, Sino-German Neuro-Oncology Molecular Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China.
authors.forename: Junwen
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, Sino-German Neuro-Oncology Molecular Laboratory, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, PR China. Electronic address: tlei@tjh.tjmu.edu.cn.
authors.forename: Ting
authors.initials: T
authors.lastname: Lei
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002070:Butadienes / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D056743:Cyclin D3 / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020662:Guanine Nucleotide Exchange Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006835:Hydrazones / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D007555:Isoxazoles / Q000494:pharmacology; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D048493:Proto-Oncogene Proteins B-raf / Q000037:antagonists & inhibitors / Q000378:metabolism; D034622:RNA Interference; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: C579558:3-(5-tert-butylisoxazol-3-yl)-2-((3-chlorophenyl)hydrazono)-3-oxopropionitrile; C473217:8-(4-chloro-phenylthio)-2'-O-methyladenosine-3'-5'-cyclic monophosphate; D002070:Butadienes; D056743:Cyclin D3; D004791:Enzyme Inhibitors; D020662:Guanine Nucleotide Exchange Factors; D006835:Hydrazones; D007546:Isoquinolines; D007555:Isoxazoles; D009570:Nitriles; C526973:Rapgef3 protein, rat; C531571:Rapgef4 protein, rat; D013449:Sulfonamides; C113580:U 0126; D005576:Colforsin; D000242:Cyclic AMP; C482123:Braf protein, rat; D048493:Proto-Oncogene Proteins B-raf; D017868:Cyclic AMP-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048369:MAP Kinase Kinase 1; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide
keywords: B-Raf; ERK; Epac; Pituitary cells; Proliferation