title: Diacerein retards cell growth of chondrosarcoma cells at the G2/M cell cycle checkpoint via cyclin B1/CDK1 and CDK2 downregulation.
abstract: BACKGROUND
  Chondrosarcoma is characterized for its lack of response to conventional cytotoxic chemotherapy, propensity for developing lung metastases, and low rates of survival. Research within the field of development and expansion of new treatment options for unresectable or metastatic diseases is of particular priority. Diacerein, a symptomatic slow acting drug in osteoarthritis (SYSADOA), implicates a therapeutic benefit for the treatment of chondrosarcoma by an antitumor activity.
  
  
  METHODS
  After treatment with diacerein the growth behaviour of the cells was analyzed with the xCELLigence system and MTS assay. Cell cycle was examined using flow cytometric analysis, RT-PCR, and western blot analysis of specific checkpoint regulators. The status for phosophorylation of mitogen-activated protein kinases (MAPKs) was analyzed with a proteome profiler assay. In addition, the possible impact of diacerein on apoptosis was investigated using cleaved caspase 3 and Annexin V/PI flow cytometric analysis.
  
  
  RESULTS
  Diacerein decreased the cell viability and the cell proliferation in two different chondrosarcoma cell lines in a dose dependent manner. Flow cytometric analysis showed a classical G2/M arrest. mRNA and protein analysis revealed that diacerein induced a down-regulation of the cyclin B1-CDK1 complex and a reduction in CDK2 expression. Furthermore, diacerein treatment increased the phosphorylation of p38α and p38β MAPKs, and Akt1, Akt2, and Akt 3 in SW-1353, whereas in Cal-78 the opposite effect has been demonstrated. These observations accordingly to our cell cycle flow cytometric analysis and protein expression data may explain the G2/M phase arrest. In addition, no apoptotic induction after diacerein treatment, neither in the Cal-78 nor in the SW-1353 cell line was observed.
  
  
  CONCLUSIONS
  Our results demonstrate for the first time that the SYSADOA diacerein decreased the viability of human chondrosarcoma cells and induces G2/M cell cycle arrest by CDK1/cyclin B1 down-regulation.
authors.affiliation: Department of Orthopedic Surgery, Medical University Graz, Auenbruggerplatz 5, A-8036, Graz, Austria. birgit.lohberger@medunigraz.at.
authors.forename: Birgit
authors.initials: B
authors.lastname: Lohberger
authors.affiliation: Department of Orthopedic Surgery, Medical University Graz, Auenbruggerplatz 5, A-8036, Graz, Austria. andreas.leithner@medunigraz.at.
authors.forename: Andreas
authors.initials: A
authors.lastname: Leithner
authors.affiliation: Department of Orthopedic Surgery, Medical University Graz, Auenbruggerplatz 5, A-8036, Graz, Austria. nicole.stuendl@klinikum-graz.at.
authors.forename: Nicole
authors.initials: N
authors.lastname: Stuendl
authors.affiliation: Department of Orthopedic Surgery, Medical University Graz, Auenbruggerplatz 5, A-8036, Graz, Austria. heike.kaltenegger@klinikum-graz.at.
authors.forename: Heike
authors.initials: H
authors.lastname: Kaltenegger
authors.affiliation: Ludwig Boltzmann Institute for Rehabilitation of Internal Diseases, Ludwig Boltzmann Cluster for Rheumatology, Balneology and Rehabilitation, Saalfelden, Austria. lbirehab@aon.at.
authors.forename: Werner
authors.initials: W
authors.lastname: Kullich
authors.affiliation: Ludwig Boltzmann Institute for Rehabilitation of Internal Diseases, Ludwig Boltzmann Cluster for Rheumatology, Balneology and Rehabilitation, Saalfelden, Austria. lbi.groebming@aon.at.
authors.forename: Bibiane
authors.initials: B
authors.lastname: Steinecker-Frohnwieser
mesh_terms: D000880:Anthraquinones / Q000008:administration & dosage*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002813:Chondrosarcoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D056744:Cyclin B1 / Q000096:biosynthesis* / Q000235:genetics; D051357:Cyclin-Dependent Kinase 2 / Q000096:biosynthesis* / Q000235:genetics; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans
chemical_list: D000880:Anthraquinones; C534699:CCNB1 protein, human; D056744:Cyclin B1; C025292:diacerein; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2