title: Intracellular calcium is a target of modulation of apoptosis in MCF-7 cells in the presence of IgA adsorbed to polyethylene glycol.
abstract: OBJECTIVE
  Clinical and epidemiological studies have indicated that breastfeeding has a protective effect on breast cancer risk. Protein-based drugs, including antibodies, are being developed to attain better forms of cancer therapy. Secretory IgA (SIgA) is the antibody class in human breast milk, and its activity can be linked to the protective effect of breastfeeding. The aim of this study was to investigate the effect of polyethylene glycol (PEG) microspheres with adsorbed SIgA on MCF-7 human breast cancer cells.
  
  
  METHODS
  The PEG microspheres were characterized by flow cytometry and fluorescence microscopy. The MCF-7 cells were obtained from American Type Culture Collection. MCF-7 cells were pre-incubated for 24 hours with or without SIgA (100 ng/mL), PEG microspheres or SIgA adsorbed in PEG microspheres (100 ng/mL). Viability, intracellular calcium release, and apoptosis in MCF-7 cells were determined by flow cytometry.
  
  
  RESULTS
  Fluorescence microscopy and flow cytometry analyses revealed that SIgA was able to adsorb to the PEG microspheres. The MCF-7 cells that were incubated with PEG microspheres with adsorbed SIgA showed decreased viability. MCF-7 cells that were incubated with SIgA or PEG microspheres with adsorbed SIgA had increased intracellular Ca(2+) levels. In the presence of SIgA, an increase in the percentage of apoptotic cells was observed. The highest apoptosis index was observed when the cells were treated with PEG microspheres with adsorbed SIgA.
  
  
  CONCLUSIONS
  These data suggest that colostral SIgA adsorbed to PEG microspheres has antitumor effects on human MCF-7 breast cancer cells and that the presence of large amounts of this protein in secreted breast milk may provide protection against breast tumors in women who breastfed.
authors.affiliation: Institute of Biological and Health Science, Federal University of Mato Grosso, Barra do Garças, Mato Grosso, Brazil.
authors.forename: Adenilda Cristina
authors.initials: AC
authors.lastname: Honorio-França
authors.affiliation: Institute of Biological and Health Science, Federal University of Mato Grosso, Barra do Garças, Mato Grosso, Brazil.
authors.forename: Gabriel Triches
authors.initials: GT
authors.lastname: Nunes
authors.affiliation: Institute of Biological and Health Science, Federal University of Mato Grosso, Barra do Garças, Mato Grosso, Brazil.
authors.forename: Danny Laura Gomes
authors.initials: DL
authors.lastname: Fagundes
authors.affiliation: Institute of Biological and Health Science, Federal University of Mato Grosso, Barra do Garças, Mato Grosso, Brazil.
authors.forename: Patrícia Gelli Feres
authors.initials: PG
authors.lastname: de Marchi
authors.affiliation: Institute of Biological and Health Science, Federal University of Mato Grosso, Barra do Garças, Mato Grosso, Brazil.
authors.forename: Rubian Trindade da Silva
authors.initials: RT
authors.lastname: Fernandes
authors.affiliation: Institute of Biological and Health Science, Federal University of Mato Grosso, Barra do Garças, Mato Grosso, Brazil; Institute of Health Sciences, University Center of Planalto de Araxá, Araxá, Minas Gerais, Brazil.
authors.forename: Juliana Luzia
authors.initials: JL
authors.lastname: França
authors.affiliation: Institute of Health Sciences, University Center of Planalto de Araxá, Araxá, Minas Gerais, Brazil.
authors.forename: Aline do Carmo
authors.initials: Ado C
authors.lastname: França-Botelho
authors.affiliation: Institute of Biological and Health Science, Federal University of Mato Grosso, Barra do Garças, Mato Grosso, Brazil.
authors.forename: Lucélia Campelo Albuquerque
authors.initials: LC
authors.lastname: Moraes
authors.affiliation: Campus Centro Oeste Dona Lindu - Federal University of São João Del Rei, Divinópolis, Minas Gerais, Brazil.
authors.forename: Fernando de Pilla
authors.initials: Fde P
authors.lastname: Varotti
authors.affiliation: Institute of Biological and Health Science, Federal University of Mato Grosso, Barra do Garças, Mato Grosso, Brazil; Campus Centro Oeste Dona Lindu - Federal University of São João Del Rei, Divinópolis, Minas Gerais, Brazil.
authors.forename: Eduardo Luzía
authors.initials: EL
authors.lastname: França
keywords: MCF-7 cells; PEG microsphere; SIgA; apoptosis; colostrum