Specificity of the volume-activated amino acid efflux pathway in cultured human breast cancer cells

D. B. Shennan, J. Thomson

Research output: Contribution to journalArticle

Abstract

It has been shown that cell swelling stimulates the efflux of taurine from MCF-7 and MDA-MB-231 cells via a pathway which has channel-like properties. The purpose of this study was to examine the specificity of the volume-activated taurine efflux pathway in both cell lines. A hyposmotic shock increased the efflux of glycine, L-alanine, AIB (α-aminoisobutyric acid), D-aspartate but not L-leucine from MDA-MB-231 and MCF-7 cells. It was evident that the time course of activation/inactivation of those amino acids whose efflux was affected by cell swelling was similar to that of volume-activated taurine efflux. The effect of exogenous ATP on swelling-induced glycine, AIB and D-aspartate efflux from MDA-MB-231 cells was similar to that found on taurine efflux. In addition, volume-activated AIB efflux from MDA-MB-231 cells, like that of swelling-induced taurine efflux, was inhibited by diiodosalicylate. Tamoxifen inhibited volume-activated taurine release from both MDA-MB-231 and MCF-7 cells. The results suggest that neutral and anionic α-amino acids are able to utilize the volume-activated taurine efflux pathway in both cell lines. The effect of tamoxifen on breast cancer growth may, in part, be related to perturbations in cell volume regulation.
Original languageEnglish
Pages (from-to)45-51
Number of pages7
JournalGeneral Physiology and Biophysics
Volume30
Issue number1
DOIs
Publication statusPublished - 2011

Keywords

  • tumors
  • apoptosis
  • channels
  • taurine
  • cellular hydration
  • decreases
  • line MCF-7
  • volume-regulation
  • tamoxifen
  • taurine efflux
  • mechanisms
  • breast cancer cells
  • cancer

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