A Novel Cellular Model to Study Angiotensin II AT2 Receptor Function in Breast Cancer Cells

Sylvie Rodrigues-Ferreira,Marina Morel,Rosana I Reis,Françoise Cormier,Véronique Baud,Claudio M Costa-Neto,Clara Nahmias

doi:10.1155/2012/745027

Abstract

Recent studies have highlighted the AT1 receptor as a potential therapeutic target in breast cancer, while the role of the AT2 subtype in this disease has remained largely neglected. The present study describes the generation and characterization of a new cellular model of human invasive breast cancer cells (D3H2LN-AT2) stably expressing high levels of Flag-tagged human AT2 receptor (Flag-hAT2). These cells exhibit high-affinity binding sites for AngII, and total binding can be displaced by the AT2-selective antagonist PD123319 but not by the AT1-selective antagonist losartan. Of interest, high levels of expression of luciferase and green fluorescent protein make these cells suitable for bioluminescence and fluorescence studies in vitro and in vivo. We provide here a novel tool to investigate the AT2 receptor functions in breast cancer cells, independently of AT1 receptor activation.

Highlights

Angiotensin II (AngII) is the biologically active peptide of the renin-angiotensin system, a well-known regulator of cardiovascular homeostasis and brain functions [1, 2]
These cells exhibit high-affinity binding sites for AngII, and total binding can be displaced by the AT2-selective antagonist PD123319 but not by the AT1-selective antagonist losartan
We provide here a novel tool to investigate the AT2 receptor functions in breast cancer cells, independently of AT1 receptor activation

Summary

Introduction

Angiotensin II (AngII) is the biologically active peptide of the renin-angiotensin system, a well-known regulator of cardiovascular homeostasis and brain functions [1, 2]. Over the past ten years, a large number of studies have unraveled an additional role for the renin-angiotensin system in proliferative pathologies such as hyperplasia and cancer [3,4,5,6,7,8]. It is generally admitted that AT1 receptor activation is responsible for most of the reported effects of AngII, whereas the AT2 receptor behaves as a negative regulator of AT1 signaling pathways [9,10,11]. Activation of the AT1 receptor triggers a large number of intracellular kinases leading to modulation of cell proliferation, migration, and inflammation, three processes closely associated with tumor progression. Studies using knockout animals have further pointed out a role for stromal AT1 receptors from the host in tumor-associated macrophages infiltration and in cancer-related angiogenesis [17, 18]

Objectives

Methods

Results