Figure 2.

Antifolate growth inhibition assay of HeLa cells under severe hypoxic conditions. Growth inhibition was performed by exposing HeLa cells to increasing concentrations of various cytotoxic drugs with or without 0.5 mM DMOG for 72 h (a–f), or severe hypoxia for 24 h (g and h), and cell survival was determined using the XTT assay. Growth inhibition was assessed using hydrophilic antifolates (a, b and g), lipophilic antifolates (c and d) or non-antifolate anticancer drugs (e, f and h). Results are normalized to the drug-free control for each treatment and are the means of at least three independent experiments performed in triplicates±S.D.