Nucleoside Transporter Inhibition Assay

For the nucleoside transporter inhibition assay, CT26 and PANC-1 cells were seeded in 96- well plates. Dipyridamole was used as a nucleoside transporter inhibitor and the cells were pre-incubated with 10 μM dipyridamole for 30 min. Different concentrations of Gem or HA-Gem (0.01-100 μM) were added to the wells and the incubation was extended along with the inhibitor for 24 and 72 h, at 37 °C and 5 % CO₂. At the end of the incubation period, media was removed from the wells and replaced with 120 µL of MTT solution. The MTT assay (as described above) was used to measure cell viability.