Erlotinib inhibits colon cancer metastasis through inactivation of TrkB‐dependent ERK signaling pathway

The distal metastasis is the main cause of death in patients with colon cancer. Tyrosine receptor kinase B (TrkB) and ERK signals may be the potential targets for the treatment of colon cancer metastasis. This study aims to investigate whether erlotinib inhibits distant metastasis of colon cancer by regulating TrkB and ERK signaling pathway. Human colon adenocarcinoma cell lines (SW480 and Caco‐2) pretreated with exogenous C‐X‐C motif chemokine ligand 8 (CXCL8) were used to assess the suppressive effect of erlotinib on tumor metastasis, including anoikis, epithelial‐mesenchymal transformation (EMT), migration, and invasion. Through TrkB overexpression, Akt suppression, and ERK suppression, the roles of TrkB, Akt, and ERK in erlotinib‐induced metastasis inhibition of colon cancer cells were explored. The results showed that erlotinib alleviated CXCL8‐induced metastasis of the colon cancer cells. Overexpression of TrkB in colon cancer cells eliminated the effect of erlotinib on anoikis, inhibition of EMT, migration, and invasion, and downregulation of p‐ERK and p‐Akt. Furthermore, the inhibition of ERK activation instead of Akt activation was found to participate in erlotinib‐mediated metastasis resistance, including anoikis, inhibition of EMT, migration, and invasion. In conclusion, erlotinib inhibits colon cancer cell anoikis resistance, EMT, migration, and invasion by inactivating TrkB‐dependent ERK signaling pathway. The present study demonstrates that erlotinib is responsible for metastasis inhibition in colon cancer through tyrosine receptor kinase B (TrkB)‐dependent downregulation of ERK signaling pathway.