Nucleoside Transport Into Cells

Role of Nucleoside Transporters SLC28 and SLC29 in Cancer Chemotherapy
  • Marçal Pastor-Anglada
  • F. Javier Casado
Part of the Cancer Drug Discovery and Development book series (CDD&D)


Nucleosides are taken up into cells by either concentrative nucleoside transporter (CNT; SLC28 gene family) or equilibrative nucleoside transporter (ENT; SLC29 gene family) nucleoside transporters, which differ in their substrate selectivity and their energy requirements. Both nucleoside transporter families have also been involved in the transmembrane transport of nucleoside-derived compounds, many of them currently used in antiviral and antitumoral therapies; hence, there is necessity for good knowledge about the function of these transporters. Some key points in the pharmacological understanding of these transporters are addressed. There is a long list of nucleoside derivatives with clinical relevance that are known to be transported by one or several nucleoside transporters; however, until recently little was known about the structural determinants that allow the molecular recognition of the substrates by their transporters. This will be a key point in the development of rationally designed new drugs. Other aspects of nucleoside transporters are also relevant to their function as drug transporters. On the one hand, several polymorphisms have been described in CNT and ENT proteins that could affect their activity, although thorough functional analysis awaits. On the other hand, tissue distribution of these transporters is not homogeneous among tissues, and their expression can be tightly regulated, thus opening the possibility of over- or underexpression of a particular transporter in transformed cells, as has been reported in several cases. All these properties of nucleoside transporters determine their role in the bioavailability and cell sensitivity to anticancer drugs, and the first studies linking nucleoside transporter function to drug sensitivity and clinical outcome in cancer patients are now reported.

Key Words

Concentrative nucleoside transporter equilibrative nucleoside transporter nucleoside uptake passive diffusion. 


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Copyright information

© Humana Press Inc., Totowa, NJ 2006

Authors and Affiliations

  • Marçal Pastor-Anglada
    • 1
  • F. Javier Casado
    • 2
  1. 1.University of BarcelonaBarcelonaSpain
  2. 2.Department of Biochemistry and Molecular BiologyUniversity of BarcelonaBarcelonaSpain

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