Figure 6: Caspase-3 expression is increased in tumors treated with QLT0267. In vitro analysis of Caspase3/7 activity was performed using a luminescent based Caspase-3/7 assay (A). As shown, treatment using QLT0267 was able to promote increased Caspase activity in vitro with a peak at 12 hours after treatment. Vehicle and QLT0267 treated tumor cores were subject to Caspase-3 staining and quantification using Aperio Image Scope software. A significant increase in Caspase-3 expression was observed (P<0.05) (B). Whole tissue sections were analyzed for Caspase-3 expression using the Aperio Image Scope software. The whole tumor section was marked off as the region of interest except region outlined in green representing necrotic tissue plus a margin was excluded from the analysis (C). The colorized image represents the mark-up after the positive pixel count algorithm was performed:blue represents negative pixels, orange positive pixels, and red strongly positive pixels (C). Note that the region selected as necrotic was not included in the mark-up image. Quantification of all sections analyzed from the 6 hour time-point shows that QLT0267 treated tissues has significantly higher Caspase-3 activation than vehicle treated tumors (P<0.05) (D). Positive control tonsil tissue (E) exhibits single positive cells scattered throughout negative tissue (see arrows). Vehicle treated tumor tissues (E) exhibits diffuse weak cytoplasmic staining with some positive cells, while QLT0267 treated tumors show increased cytoplasmic staining and an increase in the number of positive cells (E).