Nucleoside Transporters: CNTs and ENTs

2007 ◽  
pp. 171-200
Author(s):  
Li Xia ◽  
Mingyan Zhou ◽  
Joanne Wang
Keyword(s):  
Nucleoside Transporters

scholarly journals Testicular disposition of clofarabine in rats is dependent on equilibrative nucleoside transporters

2021 ◽  
Vol 9 (4) ◽  
Author(s):  
Siennah R. Miller ◽  
Joseph L. Jilek ◽  
Meghan E. McGrath ◽  
Raymond K. Hau ◽  
Erin Q. Jennings ◽  
...  
Keyword(s):  
Nucleoside Transporters ◽  
Equilibrative Nucleoside Transporters

scholarly journals Equilibrative Nucleoside Transporters Mediate the Import of Nicotinamide Riboside and Nicotinic Acid Riboside into Human Cells

2021 ◽  
Vol 22 (3) ◽  
pp. 1391
Author(s):  
Andrey Kropotov ◽  
Veronika Kulikova ◽  
Kirill Nerinovski ◽  
Alexander Yakimov ◽  
Maria Svetlova ◽  
...  
Keyword(s):  
Nicotinic Acid ◽  
Mammalian Cells ◽  
Experimental Models ◽  
The Body ◽  
Nucleoside Transporters ◽  
Hek293 Cells ◽  
Nucleoside Transporter ◽  
Vitamin B3 ◽  
Animal Cells ◽  
Nicotinamide Riboside

Nicotinamide riboside (NR), a new form of vitamin B3, is an effective precursor of nicotinamide adenine dinucleotide (NAD+) in human and animal cells. The introduction of NR into the body effectively increases the level of intracellular NAD+ and thereby restores physiological functions that are weakened or lost in experimental models of aging and various pathologies. Despite the active use of NR in applied biomedicine, the mechanism of its transport into mammalian cells is currently not understood. In this study, we used overexpression of proteins in HEK293 cells, and metabolite detection by NMR, to show that extracellular NR can be imported into cells by members of the equilibrative nucleoside transporter (ENT) family ENT1, ENT2, and ENT4. After being imported into cells, NR is readily metabolized resulting in Nam generation. Moreover, the same ENT-dependent mechanism can be used to import the deamidated form of NR, nicotinic acid riboside (NAR). However, NAR uptake into HEK293 cells required the stimulation of its active utilization in the cytosol such as phosphorylation by NR kinase. On the other hand, we did not detect any NR uptake mediated by the concentrative nucleoside transporters (CNT) CNT1, CNT2, or CNT3, while overexpression of CNT3, but not CNT1 or CNT2, moderately stimulated NAR utilization by HEK293 cells.

Structure-inhibitory profiles of nucleosides for the human intestinal N1 and N2 Na + -nucleoside transporters

2000 ◽  
Vol 46 (5) ◽  
pp. 394-402 ◽  
Author(s):  
Shivakumar D. Patil ◽  
Leock Y. Ngo ◽  
Jashvant D. Unadkat
Keyword(s):  
Nucleoside Transporters

Role of nucleoside transporters SLC28A2/3 and SLC29A1/2 genetics in ribavirin therapy

2011 ◽  
Vol 21 (5) ◽  
pp. 289-296 ◽  
Author(s):  
Alexandra Doehring ◽  
Wolf Peter Hofmann ◽  
Christina Schlecker ◽  
Stefan Zeuzem ◽  
Christoph Sarrazin ◽  
...  
Keyword(s):  
Nucleoside Transporters

Expression of Concentrative Nucleoside Transporters (SLC28A) in the Human Placenta: Effects of Gestation Age and Prototype Differentiation-Affecting Agents

2018 ◽  
Vol 15 (7) ◽  
pp. 2732-2741 ◽  
Author(s):  
Lucie Jiraskova ◽  
Lukas Cerveny ◽  
Sara Karbanova ◽  
Zuzana Ptackova ◽  
Frantisek Staud
Keyword(s):  
Human Placenta ◽  
Nucleoside Transporters ◽  
Gestation Age

scholarly journals 2-Nitroimidazole-Furanoside Derivatives for Hypoxia Imaging—Investigation of Nucleoside Transporter Interaction, 18F-Labeling and Preclinical PET Imaging

2019 ◽  
Vol 12 (1) ◽  
pp. 31
Author(s):  
Florian Maier ◽  
Anna Schweifer ◽  
Vijaya Damaraju ◽  
Carol Cass ◽  
Gregory Bowden ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Tumor Hypoxia ◽  
Radiochemical Yield ◽  
Nucleoside Transporters ◽  
Nucleoside Transporter ◽  
Hypoxia Imaging ◽  
Molar Activity ◽  
Slow Kinetics ◽  
Sugar Derivatives

The benefits of PET imaging of tumor hypoxia in patient management has been demonstrated in many examples and with various tracers over the last years. Although, the optimal hypoxia imaging agent has yet to be found, 2-nitroimidazole (azomycin) sugar derivatives—mimicking nucleosides—have proven their potential with [18F]FAZA ([18F]fluoro-azomycin-α-arabinoside) as a prominent representative in clinical use. Still, for all of these tracers, cellular uptake by passive diffusion is postulated with the disadvantage of slow kinetics and low tumor-to-background ratios. We recently evaluated [18F]fluoro-azomycin-β-deoxyriboside (β-[18F]FAZDR), with a structure more similar to nucleosides than [18F]FAZA and possible interaction with nucleoside transporters. For a deeper insight, we comparatively studied the interaction of FAZA, β-FAZA, α-FAZDR and β-FAZDR with nucleoside transporters (SLC29A1/2 and SLC28A1/2/3) in vitro, showing variable interactions of the compounds. The highest interactions being for β-FAZDR (IC50 124 ± 33 µM for SLC28A3), but also for FAZA with the non-nucleosidic α-configuration, the interactions were remarkable (290 ± 44 µM {SLC28A1}; 640 ± 10 µM {SLC28A2}). An improved synthesis was developed for β-FAZA. For a PET study in tumor-bearing mice, α-[18F]FAZDR was synthesized (radiochemical yield: 15.9 ± 9.0% (n = 3), max. 10.3 GBq, molar activity > 50 GBq/µmol) and compared to β-[18F]FAZDR and [18F]FMISO, the hypoxia imaging gold standard. We observed highest tumor-to-muscle ratios (TMR) for β-[18F]FAZDR already at 1 h p.i. (2.52 ± 0.94, n = 4) in comparison to [18F]FMISO (1.37 ± 0.11, n = 5) and α-[18F]FAZDR (1.93 ± 0.39, n = 4), with possible mediation by the involvement of nucleoside transporters. After 3 h p.i., TMR were not significantly different for all 3 tracers (2.5–3.0). Highest clearance from tumor tissue was observed for β-[18F]FAZDR (56.6 ± 6.8%, 2 h p.i.), followed by α-[18F]FAZDR (34.2 ± 7.5%) and [18F]FMISO (11.8 ± 6.5%). In conclusion, both isomers of [18F]FAZDR showed their potential as PET hypoxia tracers. Differences in uptake behavior may be attributed to a potential variable involvement of transport mechanisms.

Sign in / Sign up

Export Citation Format

Share Document