Rho kinase proteins regulate global miRNA expression in endothelial cells.

BACKGROUND Therapeutic targeting of Rho-Associated, Coiled-Coil Containing Protein Kinase (ROCK) signaling for tumor cells and tumor endothelium has shown efficacy in pre-clinical tumors models, and a better understanding of how proteins regulate tumor progression will strengthen our knowledge over disease etiology and treatment of patients with cancer. Recent reports have shown that ROCK activity is critical for the expression of a large number of mRNA transcripts across multiple cell types including endothelial cells. MATERIALS AND METHODS To examine the effects of ROCK proteins on microRNA (miRNA) expression in tumor-forming endothelial cells, we utilized microarrays to evaluate expression levels of 1088 miRNAs in vascular tumor-forming endothelial cells knocked-down for ROCK1 or ROCK2 or treated with a pharmacological inhibitor of ROCK activity. RESULTS Microarray analysis demonstrated that inhibiting ROCK activity altered global miRNA expression. We confirmed our findings using qPCR and identified cell-cycle progression, calcium transport, and neurogenesis/synaptogenesis as the most highly overrepresented predicted target gene networks for the identified miRNAs whose expression was altered by ROCK inhibition. CONCLUSION ROCK signaling induces large-scale changes in global miRNA expression and may lead to a better understanding of how these proteins affect aberrant vascular states.