title: Over-expressed human TREK-1 inhibits CHO cell proliferation via inhibiting PKA and p38 MAPK pathways and subsequently inducing G1 arrest.
abstract: OBJECTIVE
  Recent studies have shown that the two-pore-domain potassium channel TREK-1 is involved in the proliferation of neural stem cells, astrocytes and human osteoblasts. In this study, we investigated how TREK-1 affected the proliferation of Chinese hamster ovary (CHO) cells in vitro.
  
  
  METHODS
  A CHO cell line stably expressing hTREK-1 (CHO/hTREK-1 cells) was generated. TREK-1 channel currents in the cells were recorded using whole-cell voltage-clamp recording. The cell cycle distribution was assessed using flow cytometry analysis. The expression of major signaling proteins involved was detected with Western blotting.
  
  
  RESULTS
  CHO/hTREK-1 cells had a high level of TREK-1 expression, reached up to 320%±16% compared to the control cells. Application of arachidonic acid (10 μmol/L), chloroform (1 mmol/L) or etomidate (10 μmol/L) substantially increased TREK-1 channel currents in CHO/hTREK-1 cells. Overexpression of TREK-1 caused CHO cells arresting at the G1 phase, and significantly decreased the expression of cyclin D1. The TREK-1 inhibitor l-butylphthalide (1-100 μmol/L) dose-dependently attenuated TREK-1-induced G1 phase cell arrest. Moreover, overexpression of TREK-1 significantly decreased the phosphorylation of Akt (S473), glycogen synthase kinase-3β (S9) and cAMP response element-binding protein (CREB, S133), enhanced the phosphorylation of p38 (T180/Y182), but did not alter the phosphorylation and expression of signal transducer and activator of transcription 3 (STAT3).
  
  
  CONCLUSIONS
  TREK-1 overexpression suppresses CHO cell proliferation by inhibiting the activity of PKA and p38/MAPK signaling pathways and subsequently inducing G1 phase cell arrest.
authors.affiliation: State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
authors.forename: Man
authors.initials: M
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
authors.forename: Hua-Jing
authors.initials: HJ
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
authors.forename: Wei-Ping
authors.initials: WP
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Li
authors.affiliation: State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
authors.forename: Xiao-Liang
authors.initials: XL
authors.lastname: Wang
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D001572:Benzofurans / Q000494:pharmacology; D015153:Blotting, Western; D016466:CHO Cells; D049109:Cell Proliferation / Q000187:drug effects / Q000235:genetics*; D002725:Chloroform / Q000494:pharmacology; D006224:Cricetinae; D003412:Cricetulus; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors*; D005045:Etomidate / Q000494:pharmacology; D005434:Flow Cytometry; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects / Q000235:genetics; D018408:Patch-Clamp Techniques; D024683:Potassium Channels, Tandem Pore Domain / Q000037:antagonists & inhibitors / Q000235:genetics*; D015398:Signal Transduction; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors*
chemical_list: D001572:Benzofurans; D024683:Potassium Channels, Tandem Pore Domain; C103742:potassium channel protein TREK-1; D016718:Arachidonic Acid; D002725:Chloroform; C027125:3-n-butylphthalide; D017868:Cyclic AMP-Dependent Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D005045:Etomidate