Figure 2. DZNep partially competes with the uptake of purine nucleosides by hENT1 and hCNT3.

A. DZNep hindered the uptake of radiolabeled purine nucleosides in PANC-1 and MIA PaCa-2. Twenty-four hours after 5×10⁴ cells/well were seeded in a 24-well plate, cells were allowed to uptake the indicated radiolabeled nucleoside in the presence of DZNep or its respective unlabeled nucleoside. B. Inhibition of adenosine transport in Xenopus oocytes with DZNep. C. Pharmacological inhibition of hENT1 and excess uridine decreased the cytotoxicity of DZNep in MIA PaCa-2. Twenty-four hours after 3×10³ cells/well were seeded in a 96-well plate, cells were treated with increasing concentrations of DZNep in the presence of DMSO (control), 10 µM NBMPR, or 200 µM uridine. Cellular viability was measured using an MTT assay. IC₅₀ values are indicated. Significant differences between the control and each treatment were determined using the Student’s t test. Bars, SD. n = 3. *p<0.05, **p<0.01.