title: Matrine inhibits vascular smooth muscle cell proliferation by modulating the expression of cell cycle regulatory genes.
abstract: OBJECTIVE
  To investigate the effect of matrine on proliferation of vascular smooth muscle cells (VSMCs) and elucidate the underlying mechanisms.
  
  
  METHODS
  Rat aortic VSMCs were cultured in medium supplemented with 10% fetal bovine serum and treated with various concentrations (0, 5, 10, 15, and 20 mg/L) of matrine for 72 h. VSMCs proliferation and cell cycle profiling were assessed using a methylene blue incorporation assay and flow cytometry, respectively. The underlying protein signaling mechanisms were determined using Western blot analysis of the expression levels of cell cycle regulatory genes, including p53, p21, p27, cyclin D1, cyclin E, cyclin-dependent kinase 2 and 4 (cdk2, cdk4), and phosphorylated Rb. The involvement of p21 and p27 pathways was further determined using small interfering RNA (siRNA) knockdown.
  
  
  RESULTS
  Matrine inhibited VSMC proliferation in a dose-dependent manner by promoting G(1) arrest. The G(1) arrest was accompanied by up-regulation of p53 and p21 protein levels, and down-regulation of cyclin D1/cdk4, cyclin E/cdk2 and phosphorylated Rb protein levels. Matrine did not affect p27 expression. Furthermore, the anti-proliferative effect of matrine was abolished by silencing of p21, but not by silencing of p27.
  
  
  CONCLUSIONS
  Our data indicate that matrine has an inhibitory effect on VSMC proliferation via up-regulation of the p53/p21 signaling pathway and modulation of other cell cycle regulatory genes.
authors.affiliation: Department of Cardiovascular Surgery, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhu
authors.forename: Ji-mei
authors.initials: JM
authors.lastname: Chen
authors.forename: Shu-zhen
authors.initials: SZ
authors.lastname: Chen
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhang
authors.forename: Shao-yi
authors.initials: SY
authors.lastname: Zheng
authors.forename: Guang
authors.initials: G
authors.lastname: Long
authors.forename: Ji
authors.initials: J
authors.lastname: Chen
authors.forename: Zhi-ling
authors.initials: ZL
authors.lastname: Zhou
authors.forename: Rui-xin
authors.initials: RX
authors.lastname: Fan
authors.forename: Xiao-ping
authors.initials: XP
authors.lastname: Fan
authors.forename: Yan-fang
authors.initials: YF
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Zhuang
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D018797:Cell Cycle Proteins / Q000096:biosynthesis*; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D016213:Cyclins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010766:Phosphorylation; D011807:Quinolizines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation; D000093842:Matrines
chemical_list: D000470:Alkaloids; D018797:Cell Cycle Proteins; D016213:Cyclins; D011807:Quinolizines; D000093842:Matrines