A PGD(2)
receptor (DP) deficiency enhances
tumor progression accompanied by abnormal vascular expansion. In tumors, angiogenic endothelial cells highly express DP
receptor, and its deficiency accelerates
vascular leakage and
angiogenesis. Administration of a synthetic DP
agonist, BW245C, markedly suppresses
tumor growth as well as tumor hyperpermeability in WT mice, but not in DP-deficient mice. In a corneal
angiogenesis assay and a modified Miles
assay, host DP deficiency potentiates
angiogenesis and vascular hyperpermeability under COX-2-active situation, whereas exogenous administration of BW245C strongly inhibits both angiogenic properties in WT mice. In an
in vitro assay, BW245C does not affect endothelial migration and
tube formation, processes that are necessary for angiogenesis; however, it strongly improves endothelial
barrier function via an increase in
intracellular cAMP production. PGD(2) / DP
receptor is a newly identified
regulator of tumor
vascular permeability, indicating DP agonism can be exploited as a therapy for the treatment of
cancer.