EphB3 overexpression by Ad-EphB3 partially decreased Form-induced inhibition of cell viability and invasion in colon cancer cells. HCT116 cells were infected with the Ad-GFP control or Ad-EphB3, 24 h following infection cells were treated with 100 µM Form for 24 h. (A) The expression of EphB3 was analyzed by western blotting. (B) MTT assay and (C) Transwell assay were performed to determine cell viability and invasion. Data are presented as the mean ± standard deviation, *P<0.05 vs. the Control, n=5. Ad-GFP, adenovirus-green fluorescent protein; EphB3, Ephrin type-B receptor 3; Form, Formononetin. (D) HCT116 (Control), Form treatment and Ad-EphB3 infection and Form treatment (Ad-EphB3+Form) xenograft tumour masses were harvested on day 28. Photographs of tumor removed from mice in each group. (E) Form treatment significantly decreased and Ad-EphB3+Form rescued the xenograft tumour volumes and (F) tumor weights, compared with Control. *P<0.05, **P<0.01, ***P<0.001 vs. the Control.