The neuropeptide y y(1) receptor: a diagnostic marker? Expression in mcf-7 breast cancer cells is down-regulated by antiestrogens in vitro and in xenografts.

The neuropeptide Y (NPY) Y(1) receptor (Y(1)R) has been suggested as a tumor marker for in vivo imaging and as a therapeutic target. In view of the assumed link between estrogen receptor (ER) and Y(1)R in mammary carcinoma and with respect to the development of new diagnostic tools, we investigated...

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Main Authors: Martin Memminger, Max Keller, Miroslaw Lopuch, Nathalie Pop, Günther Bernhardt, Erwin von Angerer, Armin Buschauer
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2012-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3517602?pdf=render
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author Martin Memminger
Max Keller
Miroslaw Lopuch
Nathalie Pop
Günther Bernhardt
Erwin von Angerer
Armin Buschauer
author_facet Martin Memminger
Max Keller
Miroslaw Lopuch
Nathalie Pop
Günther Bernhardt
Erwin von Angerer
Armin Buschauer
author_sort Martin Memminger
collection DOAJ
description The neuropeptide Y (NPY) Y(1) receptor (Y(1)R) has been suggested as a tumor marker for in vivo imaging and as a therapeutic target. In view of the assumed link between estrogen receptor (ER) and Y(1)R in mammary carcinoma and with respect to the development of new diagnostic tools, we investigated the Y(1)R protein expression in human MCF-7 cell variants differing in ER content and sensitivity against antiestrogens. ER and Y(1)R expression were quantified by radioligand binding using [(3)H]-17β-estradiol and the Y(1)R selective antagonist [(3)H]-UR-MK114, respectively. The latter was used for cellular binding studies and for autoradiography of MCF-7 xenografts. The fluorescent ligands Cy5-pNPY (universal Y(1)R, Y(2)R and Y(5)R agonist) and UR-MK22 (selective Y(1)R antagonist), as well as the selective antagonists BIBP3226 (Y(1)R), BIIE0246 (Y(2)R) and CGP71683 (Y(5)R) were used to identify the NPY receptor subtype(s) by confocal microscopy. Y(1)R functionality was determined by mobilization of intracellular Ca(2+). Sensitivity of MCF-7 cells against antiestrogen 4-hydroxytamoxifen correlated directly with the ER content. The exclusive expression of Y(1)Rs was confirmed by confocal microscopy. The Y(1)R protein was up-regulated (100%) by 17β-estradiol (EC(50) 20 pM) and the predominant role of ERα was demonstrated by using the ERα-selective agonist "propylpyrazole triol". 17β-Estradiol-induced over-expression of functional Y(1)R protein was reverted by the antiestrogen fulvestrant (IC(50) 5 nM) in vitro. Furthermore, tamoxifen treatment of nude mice resulted in an almost total loss of Y(1)Rs in MCF-7 xenografts. In conclusion, the value of the Y(1)R as a target for therapy and imaging in breast cancer patients may be compromised due to Y(1)R down-regulation induced by hormonal (antiestrogen) treatment.
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spelling doaj.art-abef60db5c2d42e099c52d0f0c76f6022022-12-22T03:04:09ZengPublic Library of Science (PLoS)PLoS ONE1932-62032012-01-01712e5103210.1371/journal.pone.0051032The neuropeptide y y(1) receptor: a diagnostic marker? Expression in mcf-7 breast cancer cells is down-regulated by antiestrogens in vitro and in xenografts.Martin MemmingerMax KellerMiroslaw LopuchNathalie PopGünther BernhardtErwin von AngererArmin BuschauerThe neuropeptide Y (NPY) Y(1) receptor (Y(1)R) has been suggested as a tumor marker for in vivo imaging and as a therapeutic target. In view of the assumed link between estrogen receptor (ER) and Y(1)R in mammary carcinoma and with respect to the development of new diagnostic tools, we investigated the Y(1)R protein expression in human MCF-7 cell variants differing in ER content and sensitivity against antiestrogens. ER and Y(1)R expression were quantified by radioligand binding using [(3)H]-17β-estradiol and the Y(1)R selective antagonist [(3)H]-UR-MK114, respectively. The latter was used for cellular binding studies and for autoradiography of MCF-7 xenografts. The fluorescent ligands Cy5-pNPY (universal Y(1)R, Y(2)R and Y(5)R agonist) and UR-MK22 (selective Y(1)R antagonist), as well as the selective antagonists BIBP3226 (Y(1)R), BIIE0246 (Y(2)R) and CGP71683 (Y(5)R) were used to identify the NPY receptor subtype(s) by confocal microscopy. Y(1)R functionality was determined by mobilization of intracellular Ca(2+). Sensitivity of MCF-7 cells against antiestrogen 4-hydroxytamoxifen correlated directly with the ER content. The exclusive expression of Y(1)Rs was confirmed by confocal microscopy. The Y(1)R protein was up-regulated (100%) by 17β-estradiol (EC(50) 20 pM) and the predominant role of ERα was demonstrated by using the ERα-selective agonist "propylpyrazole triol". 17β-Estradiol-induced over-expression of functional Y(1)R protein was reverted by the antiestrogen fulvestrant (IC(50) 5 nM) in vitro. Furthermore, tamoxifen treatment of nude mice resulted in an almost total loss of Y(1)Rs in MCF-7 xenografts. In conclusion, the value of the Y(1)R as a target for therapy and imaging in breast cancer patients may be compromised due to Y(1)R down-regulation induced by hormonal (antiestrogen) treatment.http://europepmc.org/articles/PMC3517602?pdf=render
spellingShingle Martin Memminger
Max Keller
Miroslaw Lopuch
Nathalie Pop
Günther Bernhardt
Erwin von Angerer
Armin Buschauer
The neuropeptide y y(1) receptor: a diagnostic marker? Expression in mcf-7 breast cancer cells is down-regulated by antiestrogens in vitro and in xenografts.
PLoS ONE
title The neuropeptide y y(1) receptor: a diagnostic marker? Expression in mcf-7 breast cancer cells is down-regulated by antiestrogens in vitro and in xenografts.
title_full The neuropeptide y y(1) receptor: a diagnostic marker? Expression in mcf-7 breast cancer cells is down-regulated by antiestrogens in vitro and in xenografts.
title_fullStr The neuropeptide y y(1) receptor: a diagnostic marker? Expression in mcf-7 breast cancer cells is down-regulated by antiestrogens in vitro and in xenografts.
title_full_unstemmed The neuropeptide y y(1) receptor: a diagnostic marker? Expression in mcf-7 breast cancer cells is down-regulated by antiestrogens in vitro and in xenografts.
title_short The neuropeptide y y(1) receptor: a diagnostic marker? Expression in mcf-7 breast cancer cells is down-regulated by antiestrogens in vitro and in xenografts.
title_sort neuropeptide y y 1 receptor a diagnostic marker expression in mcf 7 breast cancer cells is down regulated by antiestrogens in vitro and in xenografts
url http://europepmc.org/articles/PMC3517602?pdf=render
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