title: Reactive oxygen species-mediated apoptosis contributes to chemosensitization effect of saikosaponins on cisplatin-induced cytotoxicity in cancer cells.
abstract: BACKGROUND
  Saikosaponin-a and -d, two naturally occurring compounds derived from Bupleurum radix, have been shown to exert anti-cancer activity in several cancer cell lines. However, the effect of combination of saikosaponins with chemotherapeutic drugs has never been addressed. Thus, we investigated whether these two saikosaponins have chemosensitization effect on cisplatin-induced cancer cell cytotoxicity.
  
  
  METHODS
  Two cervical cancer cell lines, HeLa and Siha, an ovarian cancer cell line, SKOV3, and a non-small cell lung cancer cell line, A549, were treated with saikosaponins or cisplatin individually or in combination. Cell death was quantitatively detected by the release of lactate dehydrogenase (LDH) using a cytotoxicity detection kit. Cellular ROS was analyzed by flow cytometry. Apoptosis was evaluated by AO/EB staining, flow cytometry after Anexin V and PI staining, and Western blot for caspase activation. ROS scavengers and caspase inhibitor were used to determine the roles of ROS and apoptosis in the effects of saikosaponins on cisplatin-induced cell death.
  
  
  RESULTS
  Both saikosaponin-a and -d sensitized cancer cells to cisplatin-induced cell death in a dose-dependent manner, which was accompanied with induction of reactive oxygen species (ROS) accumulation. The dead cells showed typical apoptotic morphologies. Both early apoptotic and late apoptotic cells detected by flow cytometry were increased in saikosaponins and cisplatin cotreated cells, accompanied by activation of the caspase pathway. The pan-caspase inhibitor z-VAD and ROS scavengers butylated hydroxyanisole (BHA) and N-acetyl-L-cysteine (NAC) dramatically suppressed the potentiated cytotoxicity achieved by combination of saikosaponin-a or -d and cisplatin.
  
  
  CONCLUSIONS
  These results suggest that saikosaponins sensitize cancer cells to cisplatin through ROS-mediated apoptosis, and the combination of saikosaponins with cisplatin could be an effective therapeutic strategy.
authors.affiliation: Laboratory of Molecular and Translational Medicine, West China Institute of Women and Children's Health, West China Second University Hospital, Sichuan University, Chengdu 610041, PR China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wang
authors.forename: Xue-lian
authors.initials: XL
authors.lastname: Zheng
authors.forename: Lan
authors.initials: L
authors.lastname: Yang
authors.forename: Fang
authors.initials: F
authors.lastname: Shi
authors.forename: Lin-bo
authors.initials: LB
authors.lastname: Gao
authors.forename: Ying-jia
authors.initials: YJ
authors.lastname: Zhong
authors.forename: Hong
authors.initials: H
authors.lastname: Sun
authors.forename: Fan
authors.initials: F
authors.lastname: He
authors.forename: Yong
authors.initials: Y
authors.lastname: Lin
authors.forename: Xia
authors.initials: X
authors.lastname: Wang
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002469:Cell Separation; D002945:Cisplatin / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D009369:Neoplasms / Q000378:metabolism*; D009828:Oleanolic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012503:Saponins / Q000494:pharmacology*
chemical_list: D017382:Reactive Oxygen Species; D012503:Saponins; D009828:Oleanolic Acid; D002945:Cisplatin; C025759:saikosaponin D