Figure 3.

Cytotoxicity of 5HRE/tk and GCV in VHL(–/–) and VHLmt cells. (A) 786‐O/VHL(–/–), 786‐O/VHLmt, 786‐O/VHLwt and HT1080 were exposed to GCV under aerobic (open) or hypoxic (closed) conditions. Cell viability was quantified using the MTS assay at 72 h after the end of the GCV treatment, and calculated as the ratio of the absorbance value at each condition against that incubated in medium without GCV under continuous aerobic conditions. Results are the mean of three independent experiments ± SD. (B) Cells were cultured under aerobic (A) or hypoxic (H) conditions, and expression of HSVtk mRNA was assessed using semiquantitative RT–PCR using a specific primer set. GAPDH mRNA was also analyzed as an internal control.