Fig. 4

Silencing of KLK6 induces β-catenin signaling and radioresistance (A) Western blot analysis with whole cell lysate of FaDu-Mock and FaDu-shKLK6 clones confirm similar β-catenin protein levels. Detection of β-Actin serves as control for quantity and quality of protein lysates. (B) Representative pictures of an IF staining demonstrates β-catenin localization (green signal) at the cell membrane of FaDu-Mock controls and its nuclear accumulation in FaDu-shKLK6 clones. Nuclear staining was done with Hoechst 33324 (blue staining); white bar = 20 μm. (C) Two independent FaDu-Mock and FaDu-shKLK6 clones were transfected with a TCF-dependent reporter (TOPFLASH) or a mutant control plasmid (FOPFLASH). The graph represents the relative luciferase activity as mean value + SD of three independent experiments. The value of one FOPFLASH-transfected mock control was set to one. (D) Representative pictures of a colony forming assay after irradiation with 2 or 5 Gy and of untreated controls (0 Gy). (E) The graph represents the relative survival fraction after irradiation at the indicated doses, which is displayed as mean values ± SD and was calculated by the combination of FaDu-Mock#1–3 (red line) and FaDu-shKLK#1-3 (blue line). *p-value < 0.05, ***p-value < 0.0005