Universität zu Köln

Mueller, Julian Peter and Gruendemann, Dirk (2022). Does Intracellular Metabolism Render Gemcitabine Uptake Undetectable in Mass Spectrometry? Int. J. Mol. Sci., 23 (9). BASEL: MDPI. ISSN 1422-0067

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Abstract

The ergothioneine transporter ETT (formerly OCTN1; human gene symbol SLC22A4) is a powerful and highly specific transporter for the uptake of ergothioneine (ET). Recently, Sparreboom et al. reported that the ETT would transport nucleosides and nucleoside analogues such as cytarabine and gemcitabine with the highest efficiency. In our assay system, we could not detect any such transport. Subsequently, Sparreboom suggested that the intracellular metabolization of the nucleosides occurs so fast that the original compounds cannot be detected by LC-MS/MS after inward transport. Our current experiments with 293 cells disprove this hypothesis. Uptake of gemcitabine was easily detected by LC-MS/MS measurements when we expressed the Na+/nucleoside cotransporter CNT3 (SLC28A3). Inward transport was 1280 times faster than the intracellular production of gemcitabine triphosphate. The deoxycytidine kinase inhibitor 2-thio-2 '-deoxycytidine markedly blocked the production of gemcitabine triphosphate. There was no concomitant surge in intracellular gemcitabine, however. This does not fit the rapid phosphorylation of gemcitabine. Uptake of cytarabine was very slow, but detection by MS was still possible. When the ETT was expressed and incubated with gemcitabine, there was no increase in intracellular gemcitabine triphosphate. We conclude that the ETT does not transport nucleosides.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Mueller, Julian Peter UNSPECIFIED UNSPECIFIED UNSPECIFIED Gruendemann, Dirk UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-661409
DOI:	10.3390/ijms23094690
Journal or Publication Title:	Int. J. Mol. Sci.
Volume:	23
Number:	9
Date:	2022
Publisher:	MDPI
Place of Publication:	BASEL
ISSN:	1422-0067
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language NUCLEOSIDE TRANSPORTER FAMILIES; ORGANIC CATION TRANSPORTER; ERGOTHIONEINE TRANSPORTER; HIGH-AFFINITY; CELL-LINES; EXPRESSION; GLUTAMATE; MEMBRANE; EFFLUX; SLC28 Multiple languages Biochemistry & Molecular Biology; Chemistry, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/66140