Background: Bevacizumab (Bev) resistance is hypothesized to be overcome by combining inhibitors of other signalling pathways. Objective: We aimed to study the effect of combining Bev with knocked down β-catenin (Bev-β-cat-siRNA) on the expression of VEGF-A, Slug, NFкB, and its two target genes, c-Flip and FasR, in HepG2. Expression of VEGF-A and Slug was also studied in Caco-2 cells. Methods: Cultured cells were divided into six groups 1) cells treated with Bev, 2) cells treated with β-catenin-siRNA, 3) cells treated with Bev-β-cat-siRNA, 4) cells treated with negative control, 5) cells treated with Bev-negative control, and 6) untreated cells. Expressions were assessed using qPCR and western blotting. Results: Bev-β-cat-siRNA significantly reduced the mRNA level of VEGF-A, which was initially increased in response to Bev alone in HepG2 but not in Caco-2. Additionally, Bev-β-cat-siRNA significantly decreased Slug mRNA level compared to Bev treated HepG2 cells. In contrast, VEGF-A and Slug mRNA levels in Bev group were remarkably lower than Bev-β-cat-siRNA in Caco-2 cells. Distinct β-catenin and Slug protein expressions were noticed in HepG2 and Caco-2 cells. On the other hand, Bev-β-catsiRNA remarkably reduced the level of NFкB, FasR, and c-Flip compared to Bev treated HepG2 cells, although the difference was not statistically significant. Conclusion: We conclude that combining Bevacizumab with knocked down β-catenin reduces the expression of VEGF-A and Slug in HepG2 but not in Caco-2 cells.
