FIG. 1.

Stress-induced resistance to apoptotic photokilling in ALA/light-challenged breast cancer cells: role of upregulated iNOS. COH-BR1 cells at ~ 60% confluency in serum-free medium were dark-incubated with 1-mM ALA for 45 min, switched to ALA-free medium, then irradiated with broad-band visible light for 15 min (delivered light fluence ~ 1 J/cm²). Where indicated, L-NAME (1 mM) or 1400W (10 µM) was present (added 15 min before ALA). (A) Mitochondrial localization of PpIX in ALA-treated cells, as detected by confocal fluorescence microscopy; Rh123, Rhodamine-123. (B) Quantitative RT-PCR-assessed iNOS mRNA level at various post-hν incubation times; DC, dark control (ALA-only). (C) Western blot of iNOS at indicated post-hν times; numbers below bands are iNOS/β-actin ratios normalized to DC. (D) Effects of L-NAME (N) and 1400W (W) on 20-h post-hν extent of apoptosis determined by TUNEL or Hoechst/propidium iodide (Ho/PI) assay; control (ALA- or light-alone) apoptosis was < 5% (reprinted with permission from John Wiley and Sons, Copyright 2011).²⁸