The glutamate transport inhibitor DL-Threo-β-Benzyloxyaspartic acid (DL-TBOA) differentially affects SN38- and oxaliplatin-induced death of drug-resistant colorectal cancer cells

BMC Cancer

Research Article

Sandra Christensen¹  Elena Pedraz-Cuesta¹  Stine Falsig Pedersen¹  Lennart Bunch²  Anders A. Jensen²  Jan Stenvang³  Nils Brünner³  Niels Frank Jensen³  Maria Unni Romer⁴ 

[1] Department of Biology, Faculty of Science, University of Copenhagen, 13, Universitetsparken, DK-2100, Copenhagen, Denmark;Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, 13, Universitetsparken, DK-2100, Copenhagen, Denmark;Faculty of Health and Medical Sciences, Institute of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark;Faculty of Health and Medical Sciences, Institute of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark;Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark;

关键词: SLC1A1;    EAAT3;    SLC1A3;    EAAT1;    GSH;    Glutathione;    LoVo;    HCT116;    Irinotecan;   

DOI  :  10.1186/s12885-015-1405-8

 received in 2014-12-10, accepted in 2015-04-29,  发布年份 2015

来源: Springer

【 摘 要 】

BackgroundColorectal cancer (CRC) is a leading cause of cancer death globally and new biomarkers and treatments are severely needed.MethodsHere, we employed HCT116 and LoVo human CRC cells made resistant to either SN38 or oxaliplatin, to investigate whether altered expression of the high affinity glutamate transporters Solute Carrier (SLC)-1A1 and -1A3 (EAAT3, EAAT1) is associated with the resistant phenotypes. Analyses included real-time quantitative PCR, immunoblotting and immunofluorescence analyses, radioactive tracer flux measurements, and biochemical analyses of cell viability and glutathione content. Results were evaluated using one- and two-way ANOVA and Students two-tailed t-test, as relevant.ResultsIn SN38-resistant HCT116 and LoVo cells, SLC1A1 expression was down-regulated ~60 % and up-regulated ~4-fold, respectively, at both mRNA and protein level, whereas SLC1A3 protein was undetectable. The changes in SLC1A1 expression were accompanied by parallel changes in DL-Threo-β-Benzyloxyaspartic acid (TBOA)-sensitive, UCPH101-insensitive [3H]-D-Aspartate uptake, consistent with increased activity of SLC1A1 (or other family members), yet not of SLC1A3. DL-TBOA co-treatment concentration-dependently augmented loss of cell viability induced by SN38, while strongly counteracting that induced by oxaliplatin, in both HCT116 and LoVo cells. This reflected neither altered expression of the oxaliplatin transporter Cu2+-transporter-1 (CTR1), nor changes in cellular reduced glutathione (GSH), although HCT116 cell resistance per se correlated with increased cellular GSH. DL-TBOA did not significantly alter cellular levels of p21, cleaved PARP-1, or phospho-Retinoblastoma protein, yet altered SLC1A1 subcellular localization, and reduced chemotherapy-induced p53 induction.ConclusionsSLC1A1 expression and glutamate transporter activity are altered in SN38-resistant CRC cells. Importantly, the non-selective glutamate transporter inhibitor DL-TBOA reduces chemotherapy-induced p53 induction and augments CRC cell death induced by SN38, while attenuating that induced by oxaliplatin. These findings may point to novel treatment options in treatment-resistant CRC.

【 授权许可】

Unknown   
© Pedraz-Cuesta et al.; licensee BioMed Central. 2015. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.