Effects of integrin αvβ6 on endo-exocytotic cycle of integrin αvβ5 in colon cancer cells

AIM: To investigate the effects of integrin αvβ6 on the endo-exocytotic cycle of integrin αvβ5 in colon cancer cells. METHODS: The expression of integrin αvβ6 and αvβ5 in SW480 cells, SW480 wild-type β6 cells and SW480 mock cells was detected by Western blotting. The trafficking of integrin αvβ6 and αvβ5 was examined by endocytosis assay, exocytosis assay and capture-ELISA. The adhesive and migration abilities of these 3 cell lines towards fibronectin or vitronectin were measured by cell adhesion assay and cell migration assay. RESULTS: The expression of integrin αv and β5 subunits was similar in these 3 cell lines (P>0.05), while the expression of integrin β6 subunit in SW480 wild-type β6 cells was much higher than that in the other 2 cell lines (P<0.05). The transfection of integrin β6 subunit into SW480 cells was able to slow down the endocytosis and exocytosis of integrin αvβ5, and subsequently inhibited the cellular adhesion and migration abilities towards vitronectin. CONCLUSION: Integrin αvβ6 and αvβ5 share the same αv subunit. In the process of endocytosis and exocytosis, there might be some competitive relationship between these 2 integrin isoforms. Compared with integrin αvβ5, integrin αvβ6 has the priority to get into the trafficking process, and it has subsequent effects on the adhesion and migration of colon cancer cells.