Transport of antiviral 3'-deoxy-nucleoside drugs by recombinant human and rat equilibrative,nitrobenzylthioinosine (NBMPR)-insensitive (ENT2) nucleoside transporter proteins produced in Xenopus oocytes |
| |
Authors: | Sylvia Y. M. Yao Amy M. L. Ng Manickavasagam Sundaram Carol E. Cass Stephen A. Baldwin James D. Young |
| |
Affiliation: | 1. Department of Biology, University of York, York, UK;2. Biomolecular Research, Paul Scherrer Institut, CH-5232, Villigen, Switzerland |
| |
Abstract: | In the present study, one has determined the relative role of plasma membrane equilibrative (Na+-independent) ENT nucleoside transport proteins (particularly ENT2) in the uptake of antiviral nucleoside analogues for comparison with the previously reported drug transport properties of concentrative (Na+-dependent) CNT nucleoside transport proteins. The human and rat nucleoside transport proteins hENT1, rENT1, hENT2 and rENT2 were produced in Xenopus oocytes and investigated for their ability to transport three 3'-deoxy-nucleoside analogues, ddC (2' 3'-dideoxycytidine), AZT (3'-azido-3'-deoxythymidine)and ddI (2' 3'-dideoxyinosine), used in human immunodeficiency virus (HIV) therapy. The results show, for the first time, that the ENT2 transporter isoform represents a mechanism for cellular uptake of these clinically important nucleoside drugs. Recombinant h/rENT2 transported ddC, ddI and AZT, whilst h/rENT1 transported only ddC and ddI. Relative to uridine, h/rENT2 mediated substantially larger fluxes of ddC and ddI than h/rENT1. Transplanting the amino-terminal half of rENT2 into rENT1 rendered rENT1 transport-positive for AZT and enhanced the uptake of both ddC and ddI, identifying this region as a major site of 3'-deoxy-nucleoside drug interaction. |
| |
Keywords: | Nucleoside Transport Chimeric Transporter |
|
|