U87 cell growth curves by MTT assay.

<p>Cell growth was monitored for 12 days. Three independent U87 clones for each construct, i.e. pcDNA3 (circles, continuous line), pcDNA3-prodh-wild-type (squares, dashed line), or pCDNA3-prodh-<i>L441P</i> (triangles, dotted line), were seeded in 96-well plates (1.5 x 10³ cells/well) and incubated at 37 °C in a 5% CO₂ incubator. The values of absorbance at 600 nm represent the average of three clones transfected with the same vector (mean value ± standard error, n = 6; **p ≤ 0.05 at the selected time).