A45
The role of RhoJ in endothelial cell biology and angiogenesis
Sukhbir Kaur, Sabina Hiltbrunner, Roy Bicknell, Victoria Heath
University of Birmingham, Birmingham, UK
Rho GTPases are a distinct family of molecular switches, which regulate many essential aspects of cell physiology such as cell growth, adhesion, migration and control of actin dynamics. These processes are essential for angiogenesis, a component of cancer progression. Expanding our knowledge of the molecular mechanisms underlying angiogenesis is necessary to understand fully the biology of cancer. RhoJ/TCL belongs to the cdc42-like subfamily of Rho GTPases and its expression is highly endothelial specific. Our aim was to investigate and characterise the role of RhoJ in angiogenesis.
RhoJ expression was knocked down in human umbilical vein endothelial cells using siRNA technology and various in vitro angiogenesis assays were then performed. In all assays, cells lacking RhoJ were compared with mock transfected and cells transfected with a negative control siRNA. Cell-counting assays and flow cytometry analysis revealed reduced growth and increased cell death as a result of RhoJ downregulation. In addition, wound-healing and modified Boyden chamber assays revealed a defect in chemokinesis and chemotactic movement in cells lacking RhoJ. These cells also showed a dramatic inability to form a stable tubule network when plated on the basement membrane extract, Matrigel.
Our results suggest that RhoJ plays a crucial role in regulating fundamental aspects of angiogenesis and endothelial cell biology.
