Nuclear FAK and Runx1 cooperate to regulate IGFBP3, cell cycle progression and tumor growth

Nuclear focal adhesion kinase (FAK) is a potentially important regulator of gene
expression in cancer, impacting both cellular function and the composition of the surrounding tumor microenvironment. Here we report in a murine model of skin squamous cell carcinoma (SCC) that nuclear FAK regulates Runx1-dependent transcription of insulin-like growth factor binding protein 3 (IGFBP3), and that this regulates SCC cell cycle progression and tumor growth in vivo. Furthermore, we identified a novel molecular complex between FAK and Runx1 in the nucleus of SCC cells and showed that FAK interacted with a number of Runx1 regulatory proteins, including Sin3a and other epigenetic modifiers known to alter Runx1 transcriptional function through post-translational modification. These findings provide important new insights into the role of FAK as a scaffolding protein in molecular complexes that regulate gene transcription.