The effect of various drug treatments on cell growth and proliferation in β-catenin knockout cells. Beta-catenin was silenced in colorectal cancer cells (HCT-8, panel 6A). HCT-8 wild type cells (HCT-8WT), scramble controls (HCT-8SC) and 2 β-catenin knockout clones (HCT-8RH7 and HCT-8RF4) were tested. Expression of β-catenin was significantly lower in HCT-8RH1 and HCT-8RF4 when compared with all other groups (panel 6A). Cancer cell growth and proliferation were determined in HCT-8WT, HCT-8SC, HCT-8RH7 and HCT-8RF4 after treatment with various doses of SN-38, docetaxel, paclitaxel, oxaliplatin, 5-FU and topotecan using SRB assay. HCT-8RH7 and HCT-RF4 cells were significantly more sensitive to various drug treatments when compared with HCT-8WT and HCT-8SC (panel 6B). * denotes a p value of less than 0.05 when compared with all other groups.