title: Sanguinarine inhibits Rac1b-rendered cell survival enhancement by promoting apoptosis and blocking proliferation.
abstract: OBJECTIVE
  Small GTPase Rac1 is a member of the Ras superfamily, which plays important roles in regulation of cytoskeleton reorganization, cell growth, proliferation, migration, etc. The aim of this study was to determine how a constitutively active Rac1b regulated cell proliferation and to investigate the effects of the Rac1b inhibitor sanguinarine.
  
  
  METHODS
  Three HEK293T cell lines stably overexpressing GFP, Rac1-GFP or Rac1b-GFP were constructed by lentiviral infection. The cells were treated with sanguinarine (1 μmol/L) or its analogue berberine (1 μmol/L) for 4 d. Cell proliferation was evaluated by counting cell numbers and with a BrdU incorporation assay. The levels of cleaved PARP-89 (an apoptosis marker) and cyclin-D1 (a proliferative index) were measured using Western blotting.
  
  
  RESULTS
  In 10% serum-containing media, overexpressing either Rac1 or Rac1b did not significantly change the cell proliferation. In the serum-starved media, however, the survival rate of Rac1b cells was significantly increased, whereas that of Rac1 cells was moderately increased. The level of cleaved PARP-89 was significantly increased in serum-starved Rac1 cells, but markedly reduced in serum-starved Rac1b cells. The level of cyclin-D1 was significantly increased in both serum-starved Rac1 and Rac1b cells. Treatment with sanguinarine, but not berberine, inhibited the proliferation of Rac1b cells, which was accompanied by significantly increased the level of PARP-89, and decreased both the level of cyclin-D1 and the percentage of BrdU positive cells.
  
  
  CONCLUSIONS
  Rac1b enhances the cell proliferation under a growth-limiting condition via both anti-apoptotic and pro-proliferative mechanisms. Sanguinarine, as the specific inhibitor of Rac1b, is a potential therapeutic agent for malignant tumors with up-regulated Rac1b.
authors.affiliation: 1] Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China [2] Gerontology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China.
authors.forename: Li
authors.initials: L
authors.lastname: Ying
authors.affiliation: Pediatrics, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Cardiology, Affiliated 10th People's Hospital, Shanghai Tongji University School of Medicine, Shanghai 200072, China.
authors.forename: Si-si
authors.initials: SS
authors.lastname: Wei
authors.affiliation: Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China.
authors.forename: Pei
authors.initials: P
authors.lastname: An
authors.affiliation: Pediatrics, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China.
authors.forename: Xun
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Guo
authors.affiliation: School of Chemistry and Chemical Engineering of SJTU, Shanghai 200240, China.
authors.forename: Xian-jin
authors.initials: XJ
authors.lastname: Luo
authors.affiliation: Key Laboratory of Laboratory Medicine of the Chinese Ministry of Education, Wenzhou Medical College, Wenzhou 325035, China.
authors.forename: Ji-min
authors.initials: JM
authors.lastname: Gao
authors.affiliation: Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China.
authors.forename: Yi-gang
authors.initials: YG
authors.lastname: Li
authors.affiliation: Gerontology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China.
authors.forename: Jun-li
authors.initials: JL
authors.lastname: Duan
authors.affiliation: Department of Cardiology, Affiliated Xinhua Hospital, Shanghai Jiaotong University (SJTU) School of Medicine, Shanghai 200092, China.
authors.forename: Yue-peng
authors.initials: YP
authors.lastname: Wang
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D053119:Benzophenanthridines / Q000494:pharmacology*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects*; D057809:HEK293 Cells; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology*; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*
chemical_list: D053119:Benzophenanthridines; D007546:Isoquinolines; C107953:RAC1 protein, human; C005705:sanguinarine; D020830:rac1 GTP-Binding Protein