Osmoregulation of taurine efflux from cultured human breast cancer cells: Comparison with volume activated Cl efflux and regulation by extracellular ATP

David B. Shennan, Jean Thomson, Iain F. Gow

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9 Citations (Scopus)

Abstract

The properties and regulation of volume-activated taurine efflux from MDA-MB-231 and MCF-7 cells have been investigated. Volume-activated taurine release from both cell lines was almost completely inhibited by diidosalicylate. DIDS, was more effective at inhibiting swelling-induced taurine release from MCF-7 than from MDA-MB-231 cells. On the basis of comparing taurine, Cl- and I- efflux time courses, it appears that volume-activated taurine efflux does not utilize volume-sensitive anion channels in MDA-MB-231 and MCF-7 cells. Extracellular ATP stimulated volume-activated taurine release from MDA-MB-231 cells but not from MCF-7 cells. The effect of ATP was mimicked by UTP and was dependent upon external calcium and inhibited by suramin. However, suramin inhibited volume-activated taurine efflux from both MDA-MB-231 and MCF-7 cells even in the absence of exogenously added ATP suggesting that it acts directly on the taurine efflux pathway and/or is inhibiting the effect of ATP released from the cells. Volume-activated taurine efflux from MDA-MB-231 cells was stimulated by ionomycin. In contrast, ionomycin had no effect on taurine release from MCF-7 cells. Adenosine also stimulated volume-activated taurine efflux from MDA-MB-231 cells. The results suggest that purines regulate taurine transport in MDA-MB-231 cells via more than one type of receptor.
Original languageEnglish
Pages (from-to)113-122
Number of pages9
JournalCellular Physiology and Biochemistry
Volume18
Issue number1-3
DOIs
Publication statusPublished - 2006

Keywords

  • taurine efflux
  • breast cancer cells
  • volume-regulation

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