Detection of prostate-specific membrane antigen on HUVECs in response to breast tumor-conditioned medium

Prostate-specific membrane antigen (PSMA), a well-known biomarker of prostate cancer, has also been found to be highly expressed in the neovasculature of multiple non-prostatic solid tumors. As a consequence, it has the potential to become a biomarker for tumor-associated vasculature. Herein, we describe an in vitro model for assessing PSMA expression associated with tube formation by primary human umbilical vein endothelial cells (HUVECs) cultured in Matrigel and induced by tumor-conditioned medium (TCM) derived from human breast cancer cells (MDA-MB-231). In contrast to vascular endothelial growth factor (VEGF)-containing endothelial cell medium, TCM induced higher expression of PSMA in HUVECs. The vessel-like tubes were detected by imaging with fluorescent PSMA inhibitors. Consequently, this in vitro model is expected to enable subsequent studies aimed at determining the role of PSMA in angiogenesis and factors that induce it.