Figure 3.

Cytotoxic effect of prodrug convertase. (a) In total, 10⁴ cells each were infected with measles virus (MV)-purine nucleoside phosphorylase (PNP)-anti-PSCA (multiplicity of infection (MOI) of 1) for 24 h and incubated with 5 μm fludarabine for 72 h, followed by a viability assay. Means and standard deviations from two experiments are shown (black, mock-treated cells defining 100% viability; white, fludarabine only; dark gray, MV-PNP-anti-PSCA; light gray, MV-PNP-anti-PSCA + fludarabine). (b) Cytotoxic efficacy of activated fludarabine in conditioned media. Vero-αHis cells were mock treated, treated with fludarabine only, infected with MV-PNP-anti-PSCA only (MOI = 0.1) or infected with MV-PNP-anti-PSCA and incubated with 5 μm fludarabine 36 h post-infection (p.i.) for 12 h. Different fractions (0.1 and 0.5) of conditioned and heat-inactivated media were added to a fresh layer of test cells. Viability was determined after 72 h by XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) assay. Means and standard deviations from three experiments are shown (black, mock-treated cells defining 100% viability; white, fludarabine only; dark gray, MV-PNP-anti-PSCA; light gray, MV-PNP-anti-PSCA + fludarabine).