Figure 4.

Signaling pathways involved in the MLH1‐mediated cetuximab resistance in CRC cells. A) Bioinformatics analysis: The Gene MANIA database and the STRING database were searched to make predictions. B) Western blotting was performed to detect levels of EGFR, p‐EGFR, and Her‐2 in eight CRC cell lines. β‐Actin was used as a loading control. C) MLH1 was overexpressed in HCT116 cells transfected with LV‐MLH1 and was silenced in Caco‐2 cells transfected with LV‐siMLH1. The levels of Her‐2, PI3k, AKT, and p‐AKT were detected by western blotting. β‐Actin was used as a loading control. Data are expressed as the means of three independent experiments. D,E) HCT116 cells overexpressing MLH1 were treated with an activator of the PI3K/AKT signaling pathway, while MLH1 negative control HCT116 cells were transfected with shRNA‐Her‐2. MLH1‐knockdown Caco‐2 cells were treated with an inhibitor of the PI3K/AKT signaling pathway, while MLH1 negative control Caco‐2 cells were transfected with LV‐Her‐2. The levels of Her‐2, PI3k, AKT, and p‐AKT were detected by western blotting. β‐Actin was used as a loading control.