A role for focal adhesion kinase signaling in tumor necrosis factor-α-dependent matrix metalloprotelnase-9 production in a cholangiocarcinoma cell line, CCKS1

We have previously reported that tumor necrosis factor-alpha (TNF-alpha) stimulation of CCKS1, a cell line established from cholangiocarcinoma with i.p. dissemination, dramatically increased matrix metalloproteinase-9 (MMP-9) production and tumor invasion. We investigated the role of focal adhesion kinase (FAK) in TNF-alpha-dependent production of MMP-9 in CCKS I and FAK-null mouse fibroblast cells. TNF-alpha stimulation of CCKS1 or wild-type fibroblasts substantially activated FAK phosphorylation and increased MMP-9 production. In contrast, FAK-null fibroblasts could not respond well to TNF-alpha stimulation. Conditional expression of wild-type FAK in FAK-null cells restored the TNF-alpha-dependent production of MMP-9. TNF-alpha treatment activated the kinase activity of FAK and its phosphorylation especially at Y397 and Y925. Phosphorylated FAK accumulated at focal adhesions and formed a complex with growth factor receptor binding protein 2 and SOS. In contrast, Y397F FAK and Y925F FAK, whose Y397 and Y925 were replaced with phenylalanine, respectively, as well as KD FAK, whose kinase was inactivated, could not restore the MMP-9 production. In addition, small interfering RNA against FAK drastically suppressed the TNF-alpha-dependent production of MMP-9 and inhibited the TNF-alpha-dependent invasion of CCKS1. Taken together, our results suggest the pivotal role of FAK in TNF-alpha-dependent production of MMP-9 and subsequent activation of tumor invasion.