title: Enhancing cytotoxic and apoptotic effect in OVCAR-3 and MDAH-2774 cells with all-trans retinoic acid and zoledronic acid: a paradigm of synergistic molecular targeting treatment for ovarian cancer.
abstract: BACKGROUND
  Ovarian cancer is the most fatal gynecologic malignancies in the world. Although, platinum based treatments are widely used, the disease becomes treatment refractory within two years, and novel treatment options should be searched. All- trans retinoic acid (ATRA) induces growth arrest, differentiation and cell death in some types of cancer cells and its combination with various anticancer agents results in enhanced cytotoxicity. Zoledronic acid is a common bisphosphonate known for its anticancer effects beyond its current use in the treatment of cancer-induced bone disease. We aimed to investigate the possible additive/synergistic effect of both agents in OVCAR-3 and MDAH-2774 ovarian cancer cell lines, since both agents show superiority to conventional cytotoxics in terms of adverse events.
  
  
  METHODS
  XTT cell proliferation assay was used for showing cytotoxicity. For verifying apoptosis, both DNA Fragmentation by ELISA assay and caspase 3/7 activity measurement were used. OligoGeArray which consists of 112 apoptosis related genes was used to elucidate the genetic changes within cancer cells. To validate our oligoarray results, quantitative real-time PCR was performed on four selected genes that were maximally effected by the combination treatment: lymphotoxin beta receptor (LTBR), myeloid cell leukemia-1 (MCL-1), tumor necrosis factor receptor superfamily, member 1A (TNFRSF1A), TNFRSF1A-associated death domain protein (TRADD).
  
  
  RESULTS
  We demonstrated that a novel combination of ATRA and zoledronic acid is a strong inducer of apoptotic related cell death in both ovarian cancer cells. While the combination therapy significantly induced proapoptotic genes such as tumor necrosis factor receptor superfamily (TNFRSF), TRADD and caspase 4, some of the antiapoptotic genes such as members of MCL-1, LTBR, BAG3 and Bcl-2 family members were inhibited.
  
  
  CONCLUSIONS
  These are the preliminary molecular results of a novel combination treatment of ATRA and zoledronic acid, with fewer side effects as compared to conventional cytotoxic agents. With additional experimental analysis, it may serve as a good option for the treatment of refractory and elderly ovarian cancer patients, for whom there exists very limited choice of treatment.
authors.affiliation: Division of Medical Oncology, Tulay Aktas Oncology Hospital, School of Medicine, Ege University, Bornova, Izmir, Turkey.
authors.forename: Bulent
authors.initials: B
authors.lastname: Karabulut
authors.forename: Burcak
authors.initials: B
authors.lastname: Karaca
authors.forename: Umut
authors.initials: U
authors.lastname: Varol
authors.forename: Ugur
authors.initials: U
authors.lastname: Muslu
authors.forename: Burcu
authors.initials: B
authors.lastname: Cakar
authors.forename: Harika
authors.initials: H
authors.lastname: Atmaca
authors.forename: Asli
authors.initials: A
authors.lastname: Kisim
authors.forename: Selim
authors.initials: S
authors.lastname: Uzunoglu
authors.forename: Ruchan
authors.initials: R
authors.lastname: Uslu
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D049109:Cell Proliferation / Q000187:drug effects*; D004164:Diphosphonates / Q000008:administration & dosage; D004357:Drug Synergism; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage; D020411:Oligonucleotide Array Sequence Analysis; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014212:Tretinoin / Q000008:administration & dosage; D014407:Tumor Cells, Cultured; D000077211:Zoledronic Acid
chemical_list: D014408:Biomarkers, Tumor; D004164:Diphosphonates; D007093:Imidazoles; D012333:RNA, Messenger; D014212:Tretinoin; D000077211:Zoledronic Acid