TY - JOUR
T1 - Estrogen receptor beta growth-inhibitory effects are repressed through activation of MAPK and PI3K signalling in mammary epithelial and breast cancer cells
AU - Cotrim, C. Z.
AU - Fabris, V.
AU - Doria, M. L.
AU - Lindberg, K.
AU - Gustafsson, J. Å
AU - Amado, F.
AU - Lanari, C.
AU - Helguero, L. A.
N1 - Funding Information:
We are grateful to Dr Lars-Arne Haldosén for enlightening discussions related to this work, Dr Anders Ström for T47-DERb human breast cancer cells and Dr Margaret Warner for chicken anti-ERb 503 and rabbit anti-ERb2 antibodies. This work was supported by Federal funds through Programa Operacional Temático Factores de Competitividade (COMPETE) with co-participation from the European Community Fund (FEDER) and national funds through Fundac¸ão para a Ciência e Tecnología (FCT) under the project no. PTDC/SAU-ONC/112671/2009 (LAH); Project Ciência 2008 through FCT; Mass Spectrometry Unit at University of Aveiro and Swedish Cancer Fund.
PY - 2013/5/9
Y1 - 2013/5/9
N2 - Two thirds of breast cancers express estrogen receptors (ER). ER alpha (ERα) mediates breast cancer cell proliferation, and expression of ERα is the standard choice to indicate adjuvant endocrine therapy. ERbeta (ERβ) inhibits growth in vitro; its effects in vivo have been incompletely investigated and its role in breast cancer and potential as alternative target in endocrine therapy needs further study. In this work, mammary epithelial (EpH4 and HC11) and breast cancer (MC4-L2) cells with endogenous ERα and ERβ expression and T47-D human breast cancer cells with recombinant ERβ (T47-DERβ) were used to explore effects exerted in vitro and in vivo by the ERβ agonists 2,3-bis (4-hydroxy-phenyl)-propionitrile (DPN) and 7-bromo-2-(4-hydroxyphenyl)-1,3-benzoxazol-5-ol (WAY). In vivo, ERβ agonists induced mammary gland hyperplasia and MC4-L2 tumour growth to a similar extent as the ERα agonist 4,4′,4′′-(4-propyl-(1H)- pyrazole-1,3,5-triyl) trisphenol (PPT) or 17β-estradiol (E2) and correlated with higher number of mitotic and lower number of apoptotic features. In vitro, in MC4-L2, EpH4 or HC11 cells incubated under basal conditions, ERβ agonists induced apoptosis measured as upregulation of p53 and apoptosis-inducible factor protein levels and increased caspase 3 activity, whereas PPT and E2 stimulated proliferation. However, when extracellular signal-regulated kinase 1 and 2 (ERK 1/2) were activated by co-incubation with basement membrane extract or epidermal growth factor, induction of apoptosis by ERβ agonists was repressed and DPN induced proliferation in a similar way as E2 or PPT. In a context of active ERK 1/2, phosphatidylinositol-4,5- bisphosphate 3-kinase (PI3K)/RAC-alpha serine/threonine-protein kinase (AKT) signalling was necessary to allow proliferation stimulated by ER agonists. Inhibition of MEK 1/2 with UO126 completely restored ERβ growth-inhibitory effects, whereas inhibition of PI3K by LY294002 inhibited ERβ-induced proliferation. These results show that the cellular context modulates ERβ growth-inhibitory effects and should be taken into consideration upon assessment of ERβ as target for endocrine treatment.
AB - Two thirds of breast cancers express estrogen receptors (ER). ER alpha (ERα) mediates breast cancer cell proliferation, and expression of ERα is the standard choice to indicate adjuvant endocrine therapy. ERbeta (ERβ) inhibits growth in vitro; its effects in vivo have been incompletely investigated and its role in breast cancer and potential as alternative target in endocrine therapy needs further study. In this work, mammary epithelial (EpH4 and HC11) and breast cancer (MC4-L2) cells with endogenous ERα and ERβ expression and T47-D human breast cancer cells with recombinant ERβ (T47-DERβ) were used to explore effects exerted in vitro and in vivo by the ERβ agonists 2,3-bis (4-hydroxy-phenyl)-propionitrile (DPN) and 7-bromo-2-(4-hydroxyphenyl)-1,3-benzoxazol-5-ol (WAY). In vivo, ERβ agonists induced mammary gland hyperplasia and MC4-L2 tumour growth to a similar extent as the ERα agonist 4,4′,4′′-(4-propyl-(1H)- pyrazole-1,3,5-triyl) trisphenol (PPT) or 17β-estradiol (E2) and correlated with higher number of mitotic and lower number of apoptotic features. In vitro, in MC4-L2, EpH4 or HC11 cells incubated under basal conditions, ERβ agonists induced apoptosis measured as upregulation of p53 and apoptosis-inducible factor protein levels and increased caspase 3 activity, whereas PPT and E2 stimulated proliferation. However, when extracellular signal-regulated kinase 1 and 2 (ERK 1/2) were activated by co-incubation with basement membrane extract or epidermal growth factor, induction of apoptosis by ERβ agonists was repressed and DPN induced proliferation in a similar way as E2 or PPT. In a context of active ERK 1/2, phosphatidylinositol-4,5- bisphosphate 3-kinase (PI3K)/RAC-alpha serine/threonine-protein kinase (AKT) signalling was necessary to allow proliferation stimulated by ER agonists. Inhibition of MEK 1/2 with UO126 completely restored ERβ growth-inhibitory effects, whereas inhibition of PI3K by LY294002 inhibited ERβ-induced proliferation. These results show that the cellular context modulates ERβ growth-inhibitory effects and should be taken into consideration upon assessment of ERβ as target for endocrine treatment.
KW - apoptosis
KW - breast cancer
KW - ERK 1/2
KW - estrogen receptor beta
KW - mammary gland
KW - proliferation
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U2 - 10.1038/onc.2012.261
DO - 10.1038/onc.2012.261
M3 - Article
C2 - 22751110
AN - SCOPUS:84877604335
SN - 0950-9232
VL - 32
SP - 2390
EP - 2402
JO - Oncogene
JF - Oncogene
IS - 19
ER -