title: Quantitative analysis of the anti-proliferative activity of combinations of selected iron-chelating agents and clinically used anti-neoplastic drugs.
abstract: Recent studies have demonstrated that several chelators possess marked potential as potent anti-neoplastic drugs and as agents that can ameliorate some of the adverse effects associated with standard chemotherapy. Anti-cancer treatment employs combinations of several drugs that have different mechanisms of action. However, data regarding the potential interactions between iron chelators and established chemotherapeutics are lacking. Using estrogen receptor-positive MCF-7 breast cancer cells, we explored the combined anti-proliferative potential of four iron chelators, namely: desferrioxamine (DFO), salicylaldehyde isonicotinoyl hydrazone (SIH), (E)-N'-[1-(2-hydroxy-5-nitrophenyl)ethyliden] isonicotinoyl hydrazone (NHAPI), and di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), plus six selected anti-neoplastic drugs. These six agents are used for breast cancer treatment and include: paclitaxel, 5-fluorouracil, doxorubicin, methotrexate, tamoxifen and 4-hydroperoxycyclophosphamide (an active metabolite of cyclophosphamide). Our quantitative chelator-drug analyses were designed according to the Chou-Talalay method for drug combination assessment. All combinations of these agents yielded concentration-dependent, anti-proliferative effects. The hydrophilic siderophore, DFO, imposed antagonism when used in combination with all six anti-tumor agents and this antagonistic effect increased with increasing dose. Conversely, synergistic interactions were observed with combinations of the lipophilic chelators, NHAPI or Dp44mT, with doxorubicin and also the combinations of SIH, NHAPI or Dp44mT with tamoxifen. The combination of Dp44mT with anti-neoplastic agents was further enhanced following formation of its redox-active iron and especially copper complexes. The most potent combinations of Dp44mT and NHAPI with tamoxifen were confirmed as synergistic using another estrogen receptor-expressing breast cancer cell line, T47D, but not estrogen receptor-negative MDA-MB-231 cells. Furthermore, the synergy of NHAPI and tamoxifen was confirmed using MCF-7 cells by electrical impedance data, a mitochondrial inner membrane potential assay and cell cycle analyses. This is the first systematic investigation to quantitatively assess interactions between Fe chelators and standard chemotherapies using breast cancer cells. These studies are vital for their future clinical development.
authors.affiliation: Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Prague, Czech Republic.
authors.forename: Eliska
authors.initials: E
authors.lastname: Potuckova
authors.affiliation: Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Prague, Czech Republic.
authors.forename: Hana
authors.initials: H
authors.lastname: Jansova
authors.affiliation: Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Prague, Czech Republic.
authors.forename: Miloslav
authors.initials: M
authors.lastname: Machacek
authors.affiliation: Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Prague, Czech Republic.
authors.forename: Anna
authors.initials: A
authors.lastname: Vavrova
authors.affiliation: Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Prague, Czech Republic.
authors.forename: Pavlina
authors.initials: P
authors.lastname: Haskova
authors.affiliation: Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Prague, Czech Republic.
authors.forename: Lucie
authors.initials: L
authors.lastname: Tichotova
authors.affiliation: Molecular Pharmacology and Pathology Program, Bosch Institute and Department of Pathology, University of Sydney, Sydney, Australia.
authors.forename: Vera
authors.initials: V
authors.lastname: Richardson
authors.affiliation: Molecular Pharmacology and Pathology Program, Bosch Institute and Department of Pathology, University of Sydney, Sydney, Australia.
authors.forename: Danuta S
authors.initials: DS
authors.lastname: Kalinowski
authors.affiliation: Molecular Pharmacology and Pathology Program, Bosch Institute and Department of Pathology, University of Sydney, Sydney, Australia.
authors.forename: Des R
authors.initials: DR
authors.lastname: Richardson
authors.affiliation: Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University in Prague, Prague, Czech Republic.
authors.forename: Tomas
authors.initials: T
authors.lastname: Simunek
mesh_terms: D000447:Aldehydes / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects*; D003520:Cyclophosphamide / Q000031:analogs & derivatives; D003676:Deferoxamine / Q000494:pharmacology; D004317:Doxorubicin; D004357:Drug Synergism; D005472:Fluorouracil; D006801:Humans; D006835:Hydrazones / Q000494:pharmacology; D007502:Iron Chelating Agents / Q000494:pharmacology*; D061986:MCF-7 Cells; D008727:Methotrexate; D017239:Paclitaxel; D013629:Tamoxifen; D013882:Thiosemicarbazones / Q000494:pharmacology
chemical_list: D000447:Aldehydes; D000970:Antineoplastic Agents; D006835:Hydrazones; D007502:Iron Chelating Agents; D013882:Thiosemicarbazones; C539263:di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone; C413684:salicylaldehyde isonicotinoyl hydrazone; D013629:Tamoxifen; D004317:Doxorubicin; D003520:Cyclophosphamide; D003676:Deferoxamine; D017239:Paclitaxel; D005472:Fluorouracil; C011272:perfosfamide; D008727:Methotrexate