title: Spatholobus suberectus inhibits cancer cell growth by inducing apoptosis and arresting cell cycle at G2/M checkpoint.
abstract: OBJECTIVE
  Although herbs have long been alternatively applied for cancer treatment in China, its treatment effects and their potential mechanisms have not been sufficiently investigated. The chinese herb Spatholobus suberectus (SS) is commonly prescribed to cancer patients. In this study, the anti-cancer effect of SS and its molecular mechanisms have been investigated.
  
  
  METHODS
  The effect of SS on cell proliferation was studied by cell growth assay and flow cytometry on breast cancer cell lines MCF-7 and colon cancer cell line HT-29. The role of SS in apoptosis was studied by flow cytometry, DNA fragmentation assay and mitochondrial membrane potential assay. Expression of proteins associated with cell cycle and apoptosis was determined by Western blot analysis. The in vivo effect of SS was tested in nude mouse cancer xenografts.
  
  
  RESULTS
  Cell growth assay showed that SS effectively inhibits tumor cell growth in a dose-dependent manner. Flow cytometry analysis showed that SS could arrest the cell cycle at G2/M checkpoint, which is associated with DNA damage and activation of phosphor-Chk1/Chk2. The pro-apoptotic effect of SS was demonstrated by Annexin V-PI staining and mitochondrial membrane potential assay. In vivo experiments show that the efficiency of SS alone group was superior to docetaxel or to docetaxel and SS combined. No obvious body weight loss or blood toxicity was observed in SS tested animals.
  
  
  CONCLUSIONS
  Our data demonstrates that SS is a potential herb for cancer treatment by inhibiting tumor growth via induction of apoptosis and arrest of the cell cycle at G2/M phase.
authors.affiliation: School of Chinese Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China.
authors.forename: Zhi-Yu
authors.initials: ZY
authors.lastname: Wang
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Wang
authors.forename: Tjing Yung
authors.initials: TY
authors.lastname: Loo
authors.forename: Yue
authors.initials: Y
authors.lastname: Cheng
authors.forename: Lei-Lei
authors.initials: LL
authors.lastname: Chen
authors.forename: Jian-Gang
authors.initials: JG
authors.lastname: Shen
authors.forename: De-Po
authors.initials: DP
authors.lastname: Yang
authors.forename: Louis Wing-Cheong
authors.initials: LW
authors.lastname: Chow
authors.forename: Xin-Yuan
authors.initials: XY
authors.lastname: Guan
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Chen
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002681:China; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D020834:Ethnopharmacology; D007887:Fabaceae / Q000737:chemistry; D005260:Female; D016195:G2 Phase / Q000187:drug effects; D019073:HT29 Cells; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008819:Mice, Nude; D009369:Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008517:Phytotherapy; D010946:Plants, Medicinal / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D004365:Drugs, Chinese Herbal; D017382:Reactive Oxygen Species