Kindlin-2 promotes invasiveness of prostate cancer cells via NF-κB-dependent upregulation of matrix metalloproteinases

Invasive progression is the major lethal cause of prostate cancer. In this study, we aimed to investigate the role of kindlin-2, an integrin-binding focal adhesion protein, in the regulation of invasiveness of prostate cancer. We found that downregulation of kindlin-2 using small interfering RNA (siRNA) technology significantly inhibited the invasion of PC-3 and DU-145 prostate cancer cells in a Matrigel Transwell assay. Conversely, overexpression of kindlin-2 promoted the invasiveness of prostate cancer cells. Kindlin-2 overexpression was found to activate nuclear factor (NF)-κB-dependent signaling and upregulate the expression of matrix metalloproteinase-9 (MMP-9) and MMP-2, whereas kindlin-2 silencing led to opposing effects on the expression of NF-κB and MMPs. Most importantly, kindlin-2-induced invasiveness was almost completely abolished by pretreatment with pyrrolidine dithiocarbamate (an inhibitor of NF-κB signaling) or co-transfection with MMP-9 or MMP-2 siRNA. Taken together, our data indicate that kindlin-2 promotes the invasiveness of prostate cancer cells largely through NF-κB-dependent upregulation of MMP-9 and MMP-2. Further studies are warranted to evaluate the significance of kindlin-2 as a therapeutic target for metastatic prostate cancer.