Background/aims: The study was designed to investigate a potential role and mechanisms of fibronectin in tyrosine phosphorylation of focal adhesion kinase (FAK) and invasiveness of colon cancer cells.
Methodology: A colorectal cancer cell line, Colo320, was stimulated by fibronectin with gradient concentrations. Phosphorylation of FAK tyrosine 397 (tyr-397), was detected by immunoprecipitation and western-blotting. The invasiveness of Colo320 cells was measured by the modified Boyden chamber assay. An antisense oligonucleotide of FAK was used to testify the role of FAK tyr-397 in the process of cell invasion enhanced by fibronectin.
Results: The Colo320 cell showed a dose-independence on fibronectin in its invasion and phosphorylation of FAK tyr-397. Invasion and phosphorylation of FAK tyr-397 in Colo320 reached their climax when concentration of fibronectin reached 1 nmol/L. But they did not increased accordingly when the concentrations of fibronectin reached 10 nmol/L and 100 nmol/L. Antisense oligonucleotide decreased phosphorylation of FAK tyr-397 and the invasion of Colo320 cells significantly, compared with the controls.
Conclusions: Fibronectin can promote invasion of Colo320 cells, FAK tyrosine phosphorylation plays a key role in this process. Inhibition of FAK expression can inhibit colon cancer cell invasion.