ILK silencing inhibits migration and invasion of more invasive glioblastoma cells by downregulating ROCK1 and Fascin-1.

Glioblastoma multiforme (GBM) is the most aggressive type of brain tumor and it is associated with poor survival. Integrin-linked kinase (ILK) is a serine/threonine protein pseudo-kinase that binds to the cytoplasmic domains of β1 and β3 integrins and has been previously shown to promote invasion and metastasis in many cancer types, including GBM. However, little is known regarding the exact molecular mechanism implicating ILK in GBM aggressiveness. In this study, we used two brain cell lines, the non-invasive neuroglioma H4 cells, and the highly invasive glioblastoma A172 cells, which express ILK in much higher levels than H4. We studied the effect of ILK silencing on the metastatic behavior of glioblastoma cells in vitro and elucidate the underlying molecular mechanism. We showed that siRNA-mediated silencing of ILK inhibits cell migration and invasion of the highly invasive A172 cells while it does not affect the migratory and invasive capacity of H4 cells. These data were also supported by respective changes in the expression of Rho-associated kinase 1 (ROCK1), fascin actin-bundling protein 1 (FSCN1), and matrix metalloproteinase 13 (MMP13), which are known to regulate cell migration and invasion. Our findings were further corroborated by analyzing the Cancer Genome Atlas Glioblastoma Multiforme (TCGA-GBM) dataset. We conclude that ILK promotes glioblastoma cell invasion through activation of ROCK1 and FSCN1 in vitro, providing a more exact molecular mechanism for its action.