Differential expression of osteopontin, PC4, and CEC5, a novel mRNA species, during in vitro angiogenesis.

The formation of new capillaries from preexisting blood vessels, a process termed angiogenesis, plays a key role in many physiological and pathological conditions such as wound healing, embryogenesis, and tumor growth. The aim of this study was to identify changes in endothelial cell gene expression specifically associated with angiogenesis. Using an in vitro model and the differential display strategy, we compared gene expression patterns of rat microvascular endothelial cells cultured in two (2D) and three-dimensional (3D) culture. In 2D culture, the cells express actin and proliferate, whereas in 3D culture actin expression is downregulated, and the cells are mitotically quiescent and reorganize into vascular tubes. We identified three differentially expressed genes, osteopontin, PC4, and CEC5, a novel mRNA species, with homology to calmodulin-dependent protein kinases. The expression patterns were confirmed by Northern blot analysis. In conclusion, the analysis of gene expression in endothelial cells in 3D and 3D culture allows the identification of genes differentially expressed during angiogenesis. These genes or proteins may serve as targets for therapeutic modulation of angiogenesis.