Adipocyte-Derived Leucine Aminopeptidase Suppresses Angiogenesis in Human Endometrial Carcinoma via Renin-Angiotensin System

Purpose: Angiotensin (Ang) II was reported to induce vascular endothelial growth factor (VEGF) expression in various cells. Adipocyte-derived leucine aminopeptidase (A-LAP) is a novel member of the M1 family of zinc metallopeptidases. Enzymatic characterization demonstrated that A-LAP hydrolyzes Ang II. This study examined the role of A-LAP in angiogenesis of human endometrial carcinoma. Experimental Design: We investigated whether Ang II induces VEGF expression in human endometrial carcinoma cells. To investigate the possible function of A-LAP in angiogenesis of endometrial carcinoma, we transfected A-LAP cDNA into HEC-1A cells, showing the lowest expression of A-LAP. Results: In the present study, we showed that Ang II enhanced VEGF expression in a dose-dependent manner in endometrial carcinoma cells (HEC-1A cells). Overexpression of A-LAP attenuated Ang II-induced VEGF expression in HEC-1A cells. In addition, Human umbilical vascular endothelial cell migration was increased in conditioned media from Ang II-treated wild-type cells, but not in conditioned media from Ang II-treated A-LAP-overexpressing cells (HEC-1A-A-LAP cells). In an in vivo study, we showed that A-LAP overexpression in endometrial carcinoma cells results in a reduction of VEGF immunoreactivity and the number of blood vessels within tumors. Conclusions: Our study demonstrates that it is feasible to overexpress Ang II-degrading enzymes in cultured cells and that this overexpression attenuated some effects of exogenous and endogenous Ang II. These experiments are a first step toward the development of novel strategies to selectively antagonize locally generated Ang II and suppress VEGF-induced angiogenesis in endometrial carcinoma.