fig2

Figure 2. Viability loss of ALA/light-challenged glioblastoma cells and inhibition thereof by stress-induced iNOS/NO. Cells ~ 60% confluency in serum-free medium were dark-incubated with 1 mM ALA for 30 min, switched to ALA-free medium, then irradiated with increasing fluences of broad-band visible light in the absence or presence of 25 μM 1400W (W), 1mM L-NAME (N), or 25 μM cPTIO (cP). ALA-only and light-only controls were run alongside. After treatment, cells were switched to serum-containing medium and after 20 h of dark incubation, assessed for viability by MTT assay or iNOS and nNOS status by Western blot analysis. A: U87 cells; B: U251 cells. Plotted values in (A) and (B) are means ± SEM (n = 3). Number below each NOS band is intergrated band Intensity relative to β-actin and normalized to the dark control (DC). ALA: 5-Aminolevulinic acid; PpIX: protoporphyrin IX; NO: nitric oxide; iNOS: inducible NO synthase; nNOS: neuronal NO synthase; post-hv: post-irradiation (Reproduced from Ref. 56, with permission)