Daily berry consumption attenuates β-catenin signalling and genotoxicity in colon carcinoma cells exposed to faecal water from healthy volunteers in a clinical trial

[Display omitted] •β-catenin expression is downregulated in diet supplemented with berries.•Cell proliferation is downregulated in women following Meat&Berries diet.•Genotoxicity of faecal water is attenuated in Meat&Berries diet.•N-nitroso compound formation is unaffected by supplementating berries to the diet. Berries are known to have disease preventive and anticancer properties. We studied whether supplementing a habitual diet rich in red meat with berries affects cancer biomarkers in a clinical trial with 43 healthy volunteers. We exposed Caco-2 and HCA-7 colon adenocarcinoma cells and HaCaT cells, representing non-cancerous epithelial tissue, in 2D and 3D cultures to faecal water extracted from stool samples collected at baseline and at the end of the 4-wk trial. Expression of markers from the Wnt/β-catenin and PI3K/AKT/mTOR pathways, the cell proliferation marker Ki67, and the apoptosis marker cleaved caspase-3 were detected by Western blotting and immunofluorescence staining methods. In addition, genotoxicity of faecal water and the concentration of N-nitroso compounds in the faeces were analysed. The diet supplemented with berries caused downregulation of β-catenin, PS6 as well as Ki67 signalling in the cells exposed to faecal water. Our results suggest that consuming berries as part of a habitual Western-type diet could lead to less cancerous colon metabolism and possibly lower the risk for colorectal cancer by modulating the central signalling pathways in cancer.