Metabolic signature of breast cancer cell line MCF-7: profiling of modified nucleosides via LC-IT MS coupling.
BACKGROUND
Cancer, like other diseases accompanied by strong metabolic disorders, shows characteristic effects on cell turnover rate, activity of modifying enzymes and DNA/RNA modifications, resulting also in elevated amounts of excreted modified nucleosides. For a better understanding of the impaired RNA metabolism in breast cancer cells, we screened these metabolites in the cell culture supernatants of the breast cancer cell line MCF-7 and compared it to the human mammary epithelial cells MCF-10A. The nucleosides were isolated and analyzed via 2D-chromatographic techniques: In the first dimension by cis-diol specific boronate affinity extraction and subsequently by reversed phase chromatography coupled to an ion trap mass spectrometer.


RESULTS
Besides the determination of ribonucleosides, additional compounds with cis-diol structure, deriving from cross-linked biochemical pathways, like purine-, histidine- and polyamine metabolism were detected. In total, 36 metabolites were identified by comparison of fragmentation patterns and retention time. Relation to the internal standard isoguanosine yielded normalized area ratios for each identified compound and enabled a semi-quantitative metabolic signature of both analyzed cell lines.13 of the identified 26 modified ribonucleosides were elevated in the cell culture supernatants of MCF-7 cells, with 5-methyluridine, N2,N2,7-trimethylguanosine, N6-methyl-N6-threonylcarbamoyladenosine and 3-(3-aminocarboxypropyl)-uridine showing the most significant differences. 1-ribosylimidazole-4-acetic acid, a histamine metabolite, was solely found in the supernatants of MCF-10A cells, whereas 1-ribosyl-4-carboxamido-5-aminoimidazole and S-adenosylmethionine occurred only in supernatants of MCF-7 cells.


CONCLUSIONS
The obtained results are discussed against the background of pathological changes in cell metabolism, resulting in new perspectives for modified nucleosides and related metabolites as possible biomedical markers for breast carcinoma in vivo.
Department of Pharmacology and Toxicology, Division of Clinical Pharmacology, University Hospital Tübingen, Otfried-Müller-Str, 45, 72076 Tübingen, Germany. Dino.Bullinger@uni-tuebingen.de
Dino
D
Bullinger
Hans
H
Neubauer
Tanja
T
Fehm
Stefan
S
Laufer
Christoph H
CH
Gleiter
Bernd
B
Kammerer
D000241:Adenosine / Q000031:analogs & derivatives / Q000378:metabolism; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives* / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism*; D002460:Cell Line; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D006151:Guanosine / Q000031:analogs & derivatives / Q000378:metabolism / Q000592:standards; D006801:Humans; D007093:Imidazoles / Q000378:metabolism*; D007477:Ions; D042361:Mammary Glands, Human / Q000166:cytology; D053858:Metabolic Networks and Pathways; D012263:Ribonucleosides / Q000378:metabolism*; D012266:Ribose / Q000031:analogs & derivatives* / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry; D014529:Uridine / Q000031:analogs & derivatives / Q000378:metabolism
D014408:Biomarkers, Tumor; D007093:Imidazoles; D007477:Ions; C111429:N6-methyl-N6-threonylcarbamoyladenosine; D012263:Ribonucleosides; D006151:Guanosine; C009182:ribothymidine; C008184:isoguanosine; C008940:N(2),N(2)-dimethylguanosine; C094727:ribosylimidazole acetic acid; D000620:Aminoimidazole Carboxamide; C006514:3-(3-amino-3-carboxypropyl)uridine; C011651:acadesine; D012266:Ribose; D012436:S-Adenosylmethionine; D000241:Adenosine; D014529:Uridine