Characterisation of taurine uptake in human KB MDR and non-MDR tumour cell lines in culture.
Studies on taurine transport in MDR (multidrug resistant) and non-MDR KB cancer cells show that both cell types contain Na(+)- and Cl(-)-dependent high-affinity and low-affinity transport systems selective for beta-amino acids and a taurine diffusion component. Good buffers, such as HEPES or MOPS, interfered with taurine uptake. The basal taurine Vmax measured in isoosmotic medium represented 1/5 of taurine captured by uptake in KB non-MDR, but was negligible in KB MDR cells. High-and low- affinity uptake systems were reduced by medium hyperosmolarity in both cell types. Although properties of low-and high-affinity transport systems were similar in both cell types, Vmax (but not Km) were reduced in MDR compared to non-MDR cells. Taurine uptake was unaffected by chemotherapeutic agents (doxorubicin, vinblastine) or MDR revertants (verapamil). Taurine did not affect cell proliferation of MDR or non-MDR cells nor did it alter the inhibitory effect of doxorubicin or vinblastine cell proliferation.
Wersinger
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UPR 9003 du CNRS-IRCAD, Hĵpitaux Universitaires, Strasbourg, France.
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D002021:Buffers; D002455:Cell Division / Q000187:drug effects; D004317:Doxorubicin / Q000633:toxicity; D004347:Drug Interactions; D018432:Drug Resistance, Multiple / Q000502:physiology*; D006801:Humans; D007624:KB Cells; D007700:Kinetics; D013654:Taurine / Q000493:pharmacokinetics*; D014700:Verapamil / Q000494:pharmacology; D014747:Vinblastine / Q000633:toxicity
D002021:Buffers; D013654:Taurine; D014747:Vinblastine; D004317:Doxorubicin; D014700:Verapamil