Pressure-stimulated cell adhesion contributes to the iatrogenic spread of cancer by increasing the likelihood of attachment of dislodged neoplastic cells. Central to the pressure-adhesion pathway is the interaction between focal adhesion kinase (FAK) and protein kinase B alpha, also known as Akt1. Akt1 binds and phosphorylates FAK at three serine sites (S517, 601, 695) to drive pressure-stimulated cell adhesion. Because both FAK and Akt1 are kinases, interventions targeting the interaction between the two without disturbing their kinase activity would seem worthwhile. Here I tested various peptidyl and small-molecule inhibitors of Akt1 derived from FAK and examined how they altered the FAK-Akt1 interaction. The FAK-derived peptide inhibitors were developed by serially truncating FAK and testing the ability of these fragments to bind Akt1 using pull-down assays. I identified a 7-residue peptide that disrupted the FAK-Akt1 interaction. In vitro, the 7-residue peptide was able to inhibit both pressure-stimulated FAK phosphorylation and the subsequent pressure-stimulated adhesion of colorectal adenocarcinoma cells to collagen matrices. In vivo, the same peptide prevented pressure-stimulated cell adhesion to murine surgical wounds and increase tumor-free survival times. FAK-derived small-molecule inhibitor candidates were identified using computational screening. The 7-residue peptide was used as a query against a virtual library of 10,639,555 drug-like molecules. TanimotoCombo scoring, which considers volumetric and chemical similarity, was used to assess the overlays. The top results were tested for their ability to disrupt the FAK-Akt1 interaction. The small-molecule inhibitor designated as ZINC31501681 was able to prevent FAK pull-down of Akt1, as well as pressure-stimulated FAK phosphorylation and cell adhesion. These results render further studies of both ZINC31501681 and other leads generated by the virtual screen promising with the ultimate goal being the development of a therapeutic intervention for the iatrogenic spread of colorectal carcinoma.
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