title: Synergistic anticancer effects of cisplatin and histone deacetylase inhibitors (SAHA and TSA) on cholangiocarcinoma cell lines.
abstract: Clinical application of cisplatin against cholangiocarcinoma is often associated with resistance and toxicity posing urgent demand for combination therapy. In this study, we evaluated the combined anticancer effect of cisplatin and histone deacetylase inhibitors (HDACIs), suberoylanilide hydroxamic acid (SAHA) and trichostatin A (TSA), on the cholangiocarcinoma KKU-100 and KKU-M214 cell lines. Antiproliferative activity was evaluated using MTT assay. Apoptosis induction and cell cycle arrest were analyzed by flow cytometry. Cell cycle and apoptosis regulating proteins were evaluated by western blot analysis. MTT assay showed that cisplatin, SAHA and TSA dose-dependently reduced the viability of KKU-100 and KKU-M214 cells. The combination of cisplatin and HDACIs exerted significantly more cytotoxicity than the single drugs. Combination indices below 1.0 reflect synergism between cisplatin and HDACIs, leading to positive dose reductions of cisplatin and HDACIs. Cisplatin and HDACIs alone induced G0/G1 phase arrest in KKU-100 cells, but the drug combinations increased sub-G1 percent more than either drug. However, cisplatin and HDACIs alone or in combination increased only the sub-G1 percent in KKU-M214 cells. Annexin V-FITC staining revealed that cisplatin and HDACIs combinations induced more apoptotic cell death of both KKU-100 and KKU-M214 cells than the single drug. In KKU-100 cells, growth inhibition was accompanied by upregulation of p53 and p21 and downregulation of CDK4 and Bcl-2 due to exposure to cisplatin, SAHA and TSA alone or in combination. Moreover, combination of agents exerted higher impacts on protein expression. Single agents or combination did not affect p53 expression, however, combination of cisplatin and HDACIs increased the expression of p21 in KKU-M214 cells. Taken together, cisplatin and HDACIs combination may improve the therapeutic outcome in cholangiocarcinoma patients.
authors.affiliation: Program in Biological Science, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Md Ali
authors.initials: MA
authors.lastname: Asgar
authors.affiliation: Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Gulsiri
authors.initials: G
authors.lastname: Senawong
authors.affiliation: Department of Pathology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Banchob
authors.initials: B
authors.lastname: Sripa
authors.affiliation: Program in Biological Science, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Thanaset
authors.initials: T
authors.lastname: Senawong
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D018281:Cholangiocarcinoma / Q000188:drug therapy*; D002945:Cisplatin / Q000008:administration & dosage*; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D056572:Histone Deacetylase Inhibitors / Q000008:administration & dosage*; D006801:Humans; D006877:Hydroxamic Acids / Q000008:administration & dosage; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis; D000077337:Vorinostat
chemical_list: D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D016159:Tumor Suppressor Protein p53; C012589:trichostatin A; D000077337:Vorinostat; D002945:Cisplatin