Shennan, David B. and Thomson, Jean and Gow, Iain F. and Travers, M. and Barber, M.C. (2004) L-Leucine transport in human breast cancer cells (MCF-7 and MDA-MB-231): kinetics, regulation by estrogen and molecular identity of the transporter. BBA - Biomembranes, 1664 (2). pp. 206-216. ISSN 0005-2736Full text not available in this repository. (Request a copy from the Strathclyde author)
The transport of L-leucine by two human breast cancer cell lines has been examined. L-Leucine uptake by MDA-MB-231 and MCF-7 cells was via a BCH-sensitive, Na+-independent pathway. L-Leucine uptake by both cell lines was inhibited by L-alanine, D-leucine and to a lesser extent by L-lysine but not by L-proline. Estrogen (17beta-estradiol) stimulated L-leucine uptake by MCF-7 but not by MDA-MB-231 cells. L-Leucine efflux from MDA-MB-231 and MCF-7 cells was trans-stimulated by BCH in a dose-dependent fashion. The effect of external BCH on L-leucine efflux from both cell types was almost abolished by reducing the temperature from 37 to 4 degreesC. There was, however, a significant efflux of L-leucine under zero-trans conditions which was also temperature-sensitive. L-Glutamine, L-leucine, D-leucine, L-alanine, AIB and L-lysine all trans-stimulated L-leucine release from MDA-MB-231 and MCF-7 cells. In contrast, D-alanine and L-proline had little or no effect. The anti-cancer agent melphalan inhibited L-leucine uptake by MDA-MB-231 cells but had no effect on L-leucine efflux. Quantitative real-time PCR revealed that LAT1 mRNA was approximately 200 times more abundant than LAT2 mRNA in MCF-7 cells and confirmed that MDA-MB-231 cells express LAT1 but not LAT2 mRNA. LAT1 mRNA levels were higher in MCF-7 cells than in MDA-MB-231 cells. Furthermore, LAT1 mRNA was more abundant than CD98hc mRNA in both MDA-MB-231 and MCF-7 cells. The results suggest that system L is the major transporter for L-leucine in both MDA-MB-231 and MCF-7 cells. It is possible that LAT1 may be the major molecular correlate of system L in both cell types. However, not all of the properties of system L reflected those of LAT1/LAT2/CD98hc.
|Keywords:||L-Leucine, cancer cell, estrogen, Pharmacy and materia medica, Biochemistry, Cell Biology, Biophysics|
|Subjects:||Medicine > Pharmacy and materia medica|
|Department:||Faculty of Science > Strathclyde Institute of Pharmacy and Biomedical Sciences|
|Depositing user:||Strathprints Administrator|
|Date Deposited:||12 May 2010 13:27|
|Last modified:||30 Sep 2016 02:11|