title: Calcium electroporation in three cell lines: a comparison of bleomycin and calcium, calcium compounds, and pulsing conditions.
abstract: BACKGROUND
  Electroporation with calcium (calcium electroporation) can induce ATP depletion-associated cellular death. In the clinical setting, the cytotoxic drug bleomycin is currently used with electroporation (electrochemotherapy) for palliative treatment of tumors. Calcium electroporation offers several advantages over standard treatment options: calcium is inexpensive and may readily be applied without special precautions, as is the case with cytostatic drugs. Therefore, details on the use of calcium electroporation are essential for carrying out clinical trials comparing calcium electroporation and electrochemotherapy.
  
  
  METHODS
  The effects of calcium electroporation and bleomycin electroporation (alone or in combination) were compared in three different cell lines (DC-3F, transformed Chinese hamster lung fibroblast; K-562, human leukemia; and murine Lewis Lung Carcinoma). Furthermore, the effects of electrical pulsing parameters and calcium compound on treatment efficacy were determined.
  
  
  RESULTS
  Electroporation with either calcium or bleomycin significantly reduced cell survival (p<0.0001), without evidence of a synergistic effect. Cellular death following calcium or bleomycin treatment occurred at similar applied voltages, suggesting that similar parameters should be applied. At equimolar concentrations, calcium chloride and calcium glubionate resulted in comparable decreases in cell viability.
  
  
  CONCLUSIONS
  Calcium electroporation and bleomycin electroporation significantly reduce cell survival at similar applied voltage parameters. The effect of calcium electroporation is independent of calcium compound.
  
  
  CONCLUSIONS
  This study strongly supports the use of calcium electroporation as a potential cancer therapy and the results may aid in future clinical trials.
authors.affiliation: Center for Experimental Drug and Gene Electrotransfer, Department of Oncology, Copenhagen University Hospital Herlev, Herlev Ringvej 75, 2730 Herlev, Denmark.
authors.forename: Stine Krog
authors.initials: SK
authors.lastname: Frandsen
authors.affiliation: Institute of Biomedicine, Aarhus University, Building 1160, Ole Worms Allé 4, 8000 Aarhus C, Denmark.
authors.forename: Hanne
authors.initials: H
authors.lastname: Gissel
authors.affiliation: Centre of Inflammation and Metabolism, Department of Infectious Diseases, Copenhagen University Hospital, Blegdamsvej 9, 2100 Copenhagen, Denmark.
authors.forename: Pernille
authors.initials: P
authors.lastname: Hojman
authors.affiliation: Center for Experimental Drug and Gene Electrotransfer, Department of Oncology, Copenhagen University Hospital Herlev, Herlev Ringvej 75, 2730 Herlev, Denmark; Department of Pathology, Naestved Sygehus, Ringstedgade 61, 4700 Naestved, Denmark.
authors.forename: Jens
authors.initials: J
authors.lastname: Eriksen
authors.affiliation: Center for Experimental Drug and Gene Electrotransfer, Department of Oncology, Copenhagen University Hospital Herlev, Herlev Ringvej 75, 2730 Herlev, Denmark. Electronic address: Julie.Gehl@regionh.dk.
authors.forename: Julie
authors.initials: J
authors.lastname: Gehl
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage*; D001761:Bleomycin / Q000008:administration & dosage*; D002118:Calcium / Q000008:administration & dosage*; D017610:Calcium Compounds / Q000008:administration & dosage*; D018827:Carcinoma, Lewis Lung; D006224:Cricetinae; D003412:Cricetulus; D018274:Electroporation / Q000379:methods*; D006801:Humans; D020014:K562 Cells; D051379:Mice
chemical_list: D000903:Antibiotics, Antineoplastic; D017610:Calcium Compounds; D001761:Bleomycin; D002118:Calcium
keywords: 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; ANOVA; Analysis of Variance; Bleomycin; Calcium electroporation; Cancer; Electrochemotherapy; In vitro; MTT