Combined inhibition of the FAK-Rho-ROCK signaling cascade, one of the important players in mechanotransduction, in colorectal cancers

Purpose: Colorectal cancer (CRC) is one of the most common cancer types globally, with a high mortality rate. The FAK-Rho-ROCK successive signaling cascade promotes growth, migration and invasion of cancer cells. Focal adhesions are major sites of interactions between extracellular mechanical environments and intracellular biochemical signaling molecules/cytoskeleton and therefore focal adhesion proteins have been proposed to play important roles in mechanotransduction. This study aims to evaluate the effects of combination treatments with Focal Adhesion Kinase (FAK), Rho-ROCK, and YAP/TAZ inhibitors on the proliferative and epithelial-mesenchymal transition (EMT)-related metastatic characteristics of colorectal cancer cells. Material and Methods: In vitro experiments were performed using the HCT-116 colon cancer cell line. The effects of Y-15 (FAK inhibitor), ROCK inhibitor-2, and YAP/TAZ inhibitor-2, either applied alone or in combination, on cell proliferation were analyzed using the WST-1 cell viability assay. Epithelial-mesenchymal transition (EMT) markers, E-cadherin and N-cadherin, were evaluated via immunofluorescence staining, and fluorescent intensity was analyzed using ImageJ software. Results: Y-15, when applied alone or in combination with other inhibitors, significantly reduced cell proliferation (p≤0.005). Moreover, the combination of Y-15 and ROCK inhibitor-2 increased E-cadherin levels while decreasing N-cadherin levels (p≤0.0159, p≤0.0286). While the effect of YAP/TAZ inhibitor-2 alone was limited, specific effects were observed in combination treatments. Conclusion: This study demonstrates the potential of FAK-Rho-ROCK pathway inhibitors in the treatment of colorectal cancer. The ability of Y-15, in particular, to inhibit cell viability/proliferation and metastatic processes suggests that combination strategies targeting these pathways could contribute to the development of new therapeutic approaches for CRC.