title: Sulforaphane potentiates oxaliplatin-induced cell growth inhibition in colorectal cancer cells via induction of different modes of cell death.
abstract: The objective of this study was to investigate, whether the plant-derived isothiocyanate Sulforaphane (SFN) enhances the antitumor activities of the chemotherapeutic agent oxaliplatin (Ox) in a cell culture model of colorectal cancer. Caco-2 cells were cultured under standard conditions and treated with increasing concentrations of SFN [1-20 μM] and/or Ox [100 nM-10 μM]. For co-incubation, cells were pre-treated with SFN for 24 h. Cell growth was determined by BrdU incorporation. Drug interactions were assessed using the combination-index method (CI) (Cl < 1 indicates synergism). Apoptotic events were characterized by different ELISA techniques. Protein levels were examined by Western blot analysis. Annexin V- and propidium iodide (PI) staining followed by FACS analysis was used to differentiate between apoptotic and necrotic events. SFN and Ox alone inhibited cell growth of Caco-2 cells in a dose-dependent manner, an effect, which could be synergistically enhanced, when cells were incubated with the combination of both agents. Co-treated cells further displayed distinctive morphological changes that occurred during the apoptotic process, such as cell surface exposure of phosphatidylserine, membrane blebbing as well as the occurence of cytoplasmic histone-associated DNA fragments. Further observations thereby pointed toward simultaneous activation of both extrinsic and intrinsic apoptotic pathways. With increasing concentrations and treatment duration, a shift from apoptotic to necrotic cell death could be observed. In conclusion, the data suggest that the isothiocyanate SFN sensitizes colon cancer cells to Ox-induced cell growth inhibition via induction of different modes of cell death.
authors.affiliation: Institute of Pharmaceutical Chemistry, Biozentrum, Goethe University, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany.
authors.forename: Bettina M
authors.initials: BM
authors.lastname: Kaminski
authors.forename: Andreas
authors.initials: A
authors.lastname: Weigert
authors.forename: Bernhard
authors.initials: B
authors.lastname: Brüne
authors.forename: Marco
authors.initials: M
authors.lastname: Schumacher
authors.forename: Uwe
authors.initials: U
authors.lastname: Wenzel
authors.forename: Dieter
authors.initials: D
authors.lastname: Steinhilber
authors.forename: Jürgen
authors.initials: J
authors.lastname: Stein
authors.forename: Sandra
authors.initials: S
authors.lastname: Ulrich
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D018938:Caco-2 Cells; D049109:Cell Proliferation / Q000187:drug effects; D015179:Colorectal Neoplasms; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology; D052816:Foreskin / Q000166:cytology; D006801:Humans; D017879:Isothiocyanates; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D009336:Necrosis; D009944:Organoplatinum Compounds / Q000494:pharmacology*; D000077150:Oxaliplatin; D013454:Sulfoxides; D013861:Thiocyanates / Q000494:pharmacology*
chemical_list: D000970:Antineoplastic Agents; D017879:Isothiocyanates; D009944:Organoplatinum Compounds; D013454:Sulfoxides; D013861:Thiocyanates; D000077150:Oxaliplatin; D007770:L-Lactate Dehydrogenase; C016766:sulforaphane