title: Ras/ERK1 pathway regulation of p27KIP1-mediated G1-phase cell-cycle arrest in cordycepin-induced inhibition of the proliferation of vascular smooth muscle cells.
abstract: Cordycepin, the main constituent of Cordyceps militaris, demonstrated an anti-atherogenic effect in experimental animals. However, the effects of cordycepin on cell-cycle regulation and the signaling pathway in vascular smooth muscle cells (VSMC) remain largely unknown; therefore, unexpected roles of cordycepin-induced inhibition in VSMC growth were investigated. Mechanisms in cordycepin-treated VSMC were examined via an MTT assay, a thymidine uptake experiment, FACS analysis, immunoblot analysis, kinase assay, immunoprecipitation assay, and transient transfection assays. Cordycepin inhibited cell growth, induced G1-phase cell-cycle arrest, down-regulated cyclins and cyclin-dependent kinase (CDK) expression, and up-regulated p27KIP1 expression in VSMC. Cordycepin induced activation of JNK, p38MAPK and ERK1/2. Blocking of the ERK function using either ERK1/2-specific inhibitor U0126 or a small interfering RNA (si-ERK1) reversed p27KIP1 expression, inhibition of cell growth, and decreased cell-cycle proteins in cordycepin-treated VSMC. Ras activation was increased by cordycepin. Transfection of cells with dominant negative Ras (RasN17) mutant genes rescued cordycepin-induced ERK1/2 activity, increased p27KIP1 expression, inhibited cell proliferation, and reduced cell cycle proteins. In conclusion, our findings indicate that Ras/ERK1 pathways participate in p27KIP1-mediated G1-phase cell-cycle arrest induced by cordycepin via a decrease in cyclin/CDK complexes in VSMC.
authors.affiliation: Department of Food and Biotechnology, Chungju National University, Chungju, Chungbuk 380-702, South Korea.
authors.forename: Su-Mi
authors.initials: SM
authors.lastname: Jung
authors.forename: Sung-Soo
authors.initials: SS
authors.lastname: Park
authors.forename: Wun-Jae
authors.initials: WJ
authors.lastname: Kim
authors.forename: Sung-Kwon
authors.initials: SK
authors.lastname: Moon
mesh_terms: D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects*; D032661:Cordyceps / Q000737:chemistry; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism; D003839:Deoxyadenosines / Q000302:isolation & purification / Q000494:pharmacology*; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014162:Transfection; D018631:ras Proteins / Q000378:metabolism
chemical_list: D003839:Deoxyadenosines; D050760:Cyclin-Dependent Kinase Inhibitor p27; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D018631:ras Proteins; C058120:cordycepin