title: Antineoplastic effects of Chlorella pyrenoidosa in the breast cancer model.
abstract: OBJECTIVE
  There has been considerable interest in both clinical and preclinical research about the role of phytochemicals in the reduction of risk for cancer in humans. The aim of this study was to determine the antineoplastic effects of Chlorella pyrenoidosa in experimental breast cancer in vivo and in vitro.
  
  
  METHODS
  In this experiment, the antineoplastic effects of C. pyrenoidosa in the chemoprevention of N-methyl-N-nitrosourea-induced mammary carcinogenesis in female rats were evaluated. Chlorella powder was administered through diet at concentrations of 0.3% and 3%. The experiment was terminated 14 wk after carcinogen administration. At autopsy, mammary tumors were removed and prepared for histopathological and immunohistochemical analysis. In vitro cytotoxicity assay, parameters of apoptosis, and proliferation after chlorella treatment in human breast adenocarcinoma (MCF-7) cells were carried out.
  
  
  RESULTS
  Basic parameters of experimental carcinogenesis, mechanism of action (biomarkers of apoptosis, proliferation, and angiogenesis), chosen metabolic variables, and side effects after long-term chlorella treatment in animals were assessed. Chlorella at higher concentration suppressed tumor frequency by 61% (P < 0.02) and lengthened tumor latency by 12.5 d (P < 0.02) in comparison with the controls. Immunohistochemical analysis of rat tumor cells showed caspase-7 expression increase by 73.5% (P < 0.001) and vascular endothelial growth factor receptor-2 expression decrease by 19% (P = 0.07) after chlorella treatment. In a parallel in vitro study, chlorella significantly decreased survival of MCF-7 cells in a dose-dependent manner. In chlorella-treated MCF-7 cells, a significant increase in cells having sub-G0/G1 DNA content and significant increase of early apoptotic and late apoptotic/necrotic cells after annexin V/PI staining assay were found. Decreases in mitochondrial membrane potential and increasing reactive oxygen species generation were observed in the chlorella-treated MCF-7 cells.
  
  
  CONCLUSIONS
  This study is the first report on the antineoplastic effects of C. pyrenoidosa in experimental breast cancer in vivo and in vitro.
authors.affiliation: Department of Medical Biology, Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia. Electronic address: kubatka@jfmed.uniba.sk.
authors.forename: Peter
authors.initials: P
authors.lastname: Kubatka
authors.affiliation: Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia.
authors.forename: Andrea
authors.initials: A
authors.lastname: Kapinová
authors.affiliation: International Clinical Research Center, St. Anne's University Hospital and Masaryk University, Brno, Czech Republic.
authors.forename: Peter
authors.initials: P
authors.lastname: Kružliak
authors.affiliation: Department of Pharmacology, Faculty of Medicine, P. J. Šafárik University, Košice, Slovakia.
authors.forename: Martin
authors.initials: M
authors.lastname: Kello
authors.affiliation: Department of Anatomy, Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia.
authors.forename: Desanka
authors.initials: D
authors.lastname: Výbohová
authors.affiliation: Department of Pathology, Slovak Medical University and St. Elisabeth Oncology Institute, Bratislava, Slovakia.
authors.forename: Karol
authors.initials: K
authors.lastname: Kajo
authors.affiliation: International Clinical Research Center, St. Anne's University Hospital and Masaryk University, Brno, Czech Republic.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Novák
authors.affiliation: Department of Pharmacology, Faculty of Medicine, P. J. Šafárik University, Košice, Slovakia.
authors.forename: Martina
authors.initials: M
authors.lastname: Chripková
authors.affiliation: Department of Histology and Embryology, Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia.
authors.forename: Marián
authors.initials: M
authors.lastname: Adamkov
authors.affiliation: Department of Medical Biology, Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia.
authors.forename: Martin
authors.initials: M
authors.lastname: Péč
authors.affiliation: Department of Pharmacology, Faculty of Medicine, P. J. Šafárik University, Košice, Slovakia.
authors.forename: Ján
authors.initials: J
authors.lastname: Mojžiš
authors.affiliation: Department of Animal Physiology, Institute of Biological and Ecological Sciences, Faculty of Science, P. J. Šafárik University, Košice, Slovakia.
authors.forename: Bianka
authors.initials: B
authors.lastname: Bojková
authors.affiliation: Department of Animal Physiology, Institute of Biological and Ecological Sciences, Faculty of Science, P. J. Šafárik University, Košice, Slovakia.
authors.forename: Monika
authors.initials: M
authors.lastname: Kassayová
authors.affiliation: Department of Biology and Ecology, Faculty of Education, Catholic University in Ružomberok, Ružomberok, Slovakia.
authors.forename: Nadežda
authors.initials: N
authors.lastname: Stollárová
authors.affiliation: Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia.
authors.forename: Dušan
authors.initials: D
authors.lastname: Dobrota
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D049109:Cell Proliferation; D002708:Chlorella; D004032:Diet; D005260:Female; D006801:Humans; D061986:MCF-7 Cells; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D058086:Microalgae; D008517:Phytotherapy; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D017304:Annexin A5; D000972:Antineoplastic Agents, Phytogenic; D017382:Reactive Oxygen Species; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D053179:Caspase 7
keywords: Angiogenesis; Apoptosis; Cell proliferation; Chlorella; MCF-7; Mammary carcinogenesis; Rat