Figure 4.

Isogenic radiation-resistant CRC cells show elevated Wnt/β-catenin signaling activity. (A) SW1463 cells were repetitively irradiated with 2 Gy (total dose of 68 Gy), which resulted in a cell population (SW1463_RES) with a decreased sensitivity to irradiation (P = 0.0575; ANOVA model). (B) This increased treatment resistance was accompanied by a significantly increased TCF/LEF transcriptional activity (P = 0.002). (C) Protein levels of both active and total β-catenin were elevated in radiation-resistant SW1463_RES cells. Proteins were isolated as cytosolic and nuclear fractions (left panel) and whole protein lysates (right panel). Each experiment was repeated three times. Data are displayed as mean values, n = 3, error bars ± SEM. (D) SW1463_RES cells activate distinct pathways in response to a single dose of 4 Gy of X-Rays compared to SW1463 cells. Pathway analysis is based on gene expression profiles of three biological replicates of each condition (SW1463, SW1463-4 Gy, SW1463_RES, SW1463_RES-4 Gy).