Pirfenidone inhibits motility of NSCLC cells by interfering with the urokinase system

Pirfenidone (PFD) is an orally available synthetic drug which has been approved for the treatment of idiopathic pulmonary fibrosis. In addition to its anti-fibrotic properties, PFD also exerts anti-tumor effects in cancer models by inducing alterations in the tumor microenvironment. Here, we demonstrate that PFD reduces proliferation, 2D- and 3D-migration as well as colony formation of the non-small-cell lung carcinoma (NSCLC) cells. On a molecular level, we show that PFD on the one hand interacts with plasminogen activator inhibitor-1 (PAI-1; K-d of 46.2 +/- 11.3 nM) and affects its inhibitory potency, but on the other hand it also increases PAI-1 expression; in both cases consequently leading to the reduction of urokinase (uPA) activity. Finally, we report that the effect of PFD on 2D-migration of NSCLC cells depends on PAI-1 expression and thus on the activity of the uPA system whereas the PFD-induced changes in cancer cell proliferation, 3D-migration and colony formation are PAI-1 independent. To conclude, a direct interference of PFD with the uPA-PAI-1 system may deregulate pericellular proteolytic activity and thereby influence the stability of the tumor blood vessels and the matrix architecture within tumor stroma.