TABLE 1

Uptake of naturally-occurring nucleotides, nucleobases and nucleosides in empty vector and hOAT2 transfected cells

The mean uptake values of nucleotides, nucleobases, and nuclesides in the absence and presence of NBMPR (10 μM) are shown. The uptake of PAH (a known hOAT2 substrate) and gemcitabine (a known ENT substrate), are shown for comparison. Each value represents the mean ± S.D. ENT -fold transport was calculated by dividing empty vector transport in the absence of NBMPR by empty vector transport in the presence of NBMPR.


Compound

Uptake Rate in the Absence of NBMPR

Uptake Rate in the Presence of NBMPR

ENT Transport
EV
hOAT2
EV
hOAT2
pmol/mg protein/min -fold
cGMP 0.0710 ± 0.0315 4.11 ± 1.65 0.0380 ± 0.0196 3.26 ± 0.819 1.87
Guanine 0.263 ± 0.119 0.804 ± 0.513 0.0859 ± 0.0292 0.604 ± 0.313 3.06
Adenine 0.412 ± 0.0578 1.30 ± 0.239 0.262 ± 0.0530 1.10 ± 0.212 1.57
Guanosine 0.109 ± 0.0575 0.226 ± 0.169 0.0775 ± 0.0110 0.225 ± 0.163 1.41
GMP 0.00935 ± 0.00813 0.0196 ± 0.0190 0.00113 ± 0.000545 0.0185 ± 0.0185 8.27
GDP 0.00638 ± 0.000838 0.0110 ± 0.00328 0.00218 ± 0.0000522 0.00892 ± 0.00271 2.93
GTP 0.00724 ± 0.000970 0.0113 ± 0.00135 0.00143 ± 0.000502 0.00901 ± 0.00216 5.06
PAH 0.0228 ± 0.00326 0.0344 ± 0.00699 0.0265 ± 0.00684 0.0312 ± 0.00568 0.860
2′-Deoxyguanosine 0.0551 ± 0.0234 0.0790 ± 0.0314 0.00313 ± 0.000745 0.0740 ± 0.0262 17.6
Uracil 0.0280 ± 0.00870 0.0411 ± 0.00825 0.0198 ± 0.00725 0.0258 ± 0.00333 1.41
Uridine 1.14 ± 0.242 1.34 ± 0.102 0.115 ± 0.0305 0.151 ± 0.0224 9.91
Hypoxanthine 0.351 ± 0.0523 0.403 ± 0.0351 0.123 ± 0.0171 0.203 ± 0.0304 2.85
Thymine 0.00774 ± 0.00451 0.00845 ± 0.00544 0.00585 ± 0.00296 0.00707 ± 0.00394 1.32
Adenosine 0.108 ± 0.0353 0.126 ± 0.0133 0.0295 ± 0.00581 0.0521 ± 0.0132 3.66
Thymidine 0.306 ± 0.0694 0.331 ± 0.0306 0.0338 ± 0.00415 0.0391 ± 0.00254 9.05
Cytidine 0.0548 ± 0.0177 0.0571 ± 0.00903 0.00194 ± 0.000239 0.00463 ± 0.00145 28.2
Cytosine 0.0101 ± 0.00552 0.0112 ± 0.00124 0.00768 ± 0.00512 0.00704 ± 0.00176 1.32
Inosine 0.306 ± 0.0904 0.282 ± 0.0174 0.0193 ± 0.00159 0.0354 ± 0.00524 15.8
Gemcitabine
0.699 ± 0.0958
N/A
0.0998 ± 0.0343
N/A
7.00