title: Cryptotanshinone enhances the effect of Arsenic trioxide in treating liver cancer cell by inducing apoptosis through downregulating phosphorylated- STAT3 in vitro and in vivo.
abstract: BACKGROUND
  Arsenic trioxide (ATO) is approved for treating terminal-stage liver cancer in China. Cryptotanshinone (CT), a STAT3 inhibitor, has exhibited certain anti-tumor potency; however, the use of CT enhanced ATO for treating liver cancer has not been reported. Here we try to elucidate how CT could enhance the efficacy of ATO for treating liver cancer and its correlation to STAT3 in vitro and in vivo.
  
  
  METHODS
  Cell viability of ATO combined with CT was assessed by1MTT assay. Cell apoptosis induced by ATO combined with CT was detected by Annexin V/PI staining and apoptosis-related proteins were detected by western blotting. STAT3-related proteins were analysis by western blotting analysis and Immunofluorescence assays. Efficacy evaluation of ATO combined with CT on xenograft was carried in nude mice and related proteins were analysis by Immunohistochemistry assays.
  
  
  RESULTS
  First we evaluated cell vitality, and our data indicated that the ATO combined with CT showed obvious growth inhibition of Bel-7404 cells compared to ATO or CT alone. Next we found that ATO combined with CT induced cell apoptosis in Bel-7404 cells and upregulated the activation of apoptosis-related proteins cleaved-caspase-3, cleaved-caspase-9, and cleaved-poly(ADP-ribose) polymerase in a time-dependent manner. Next, we found that ATO combined with CT not only inhibited the constitutive levels of phosphorylated-JAK2 and phosphorylated-STAT3Tyr705but did so in a time-dependent manner. We also found that ATO combined with CT reversed the upregulated expression of phosphorylated-STAT3Tyr705stimulated by interleukin-6 and downregulated STAT3 direct target genes and the anti-apoptotic proteins Bcl-2, XIAP, and survivin but obviously upregulated the promoting apoptosis proteins Bak,.In vivo studies showed that ATO combined with CT decreased tumor growth. Tumors from ATO combined with CT-treated mice showed decreased levels of phosphorylated-STAT3Tyr705and the anti-apoptotic protein Bcl-2 but an increased level of pro-apoptotic protein Bax.
  
  
  CONCLUSIONS
  Our study provides strong evidence that CT could enhance the efficacy of ATO in treating liver cancer both in vitro and in vivo. Downregulation of phosphorylated-STAT3 expression may play an important role in inducing apoptosis of Bel-7404 cells.
authors.affiliation: College of Basic Medical Science, Zhejiang Chinese Medical University, 548 Bin Wen Road, Hangzhou, 310053, Zhejiang Province, China.|Center for post-doctoral studies, China Academy of Chinese Medicine Science, Beijing, China.
authors.forename: Li
authors.initials: L
authors.lastname: Shen
authors.affiliation: College of pharmacy, Zhejiang Chinese Medicine University, Hang Zhou, People's Republic of China.
authors.forename: Guangshun
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Institute of Pharmacology, Zhejiang Chinese Medicine University, Hang Zhou, People's Republic of China.
authors.forename: Zhaohuan
authors.initials: Z
authors.lastname: Lou
authors.affiliation: First People's Hospital of Xiaoshan District in Hangzhou, Hang Zhou, China.
authors.forename: Guanhua
authors.initials: G
authors.lastname: Xu
authors.affiliation: College of Basic Medical Science, Zhejiang Chinese Medical University, 548 Bin Wen Road, Hangzhou, 310053, Zhejiang Province, China. zgj@zcmu.edu.cn.
authors.forename: Guangji
authors.initials: G
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D015536:Down-Regulation / Q000187:drug effects; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010087:Oxides / Q000494:pharmacology*; D010616:Phenanthrenes / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D001152:Arsenicals; D010087:Oxides; D010616:Phenanthrenes; D050796:STAT3 Transcription Factor; C037886:cryptotanshinone; D000077237:Arsenic Trioxide
keywords: Arsenic trioxide; Cell apoptosis; Cryptotanshinone; Liver cancer