Mechanotransduction Pathways Promoting Tumor Progression Are Activated in Invasive Human Squamous Cell Carcinoma

Cutaneous squamous cell carcinomas (SCCs) are commonly diagnosed skin cancers that may progress to invasiveness in the absence of early intervention. Using a murine model of SCC, we have previously demonstrated that activation of the Rho-associated kinase (ROCK) signaling pathway promotes rapid progression of pre-neoplastic lesions to invasive SCC. Herein we demonstrate that in human cutaneous SCC, ROCK signaling is increasingly up-regulated with tumor progression in both tumor cells and cells of the tumor microenvironment and is accompanied by key tumor-promoting changes in the extracellular matrix protein composition. The mechanotransduction pathway mediated by integrin signaling through FAK, GSK3β, and the transcription coactivator β-catenin is also progressively activated in human cutaneous SCC. Our observations indicate that ROCK activation is a tumor promoter in human cutaneous SCC and acts via mechanotransduction of signals to β-catenin. Our experiments raise the possibility that inhibition of ROCK signaling could be a useful therapeutic approach to halt cutaneous SCC progression by reducing the signal flux through this pathway to physiologic levels, thereby normalizing the extracellular matrix composition.