Article type: Research Article
Authors: Hurtado, Antoni | Pinós, Tomàs; | Barbosa-Desongles, Anna; | López-Avilés, Sandra | Barquinero, Jordi | Petriz, Jordi | Santamaria-Martínez, Albert | Morote, Joan | de Torres, Inés | Bellmunt, Joaquim | Reventós, Jaume | Munell, Francina;
Affiliations: Unitat de Recerca Biomèdica, Institut de Recerca, Hospital Universitari Vall d'Hebrón, 8035 Barcelona, Spain | Departatment de Biologia Cellular i Anatomia Patológica, Facultat de Medicina, Universitat de Barcelona, Hospital Clínic, 08036 Barcelona, Spain | Unitat de Diagnostic i Terapia Molecular, Banc de Sang i Teixits, 08035 Barcelona, Spain | Servei d'Urologia, Hospital Universitari Vall d'Hebrón, 08035 Barcelona, Spain | Servei d'Anatomia Patológica, Hospital Universitari Vall d'Hebrón, 08035 Barcelona, Spain | Servei d'Oncologia, Hospital Universitari Vall d'Hebrón, 08035 Barcelona, Spain
Note: [] Authors contributed equally to this work.
Note: [] Authors contributed equally to this work.
Note: [] Corresponding author: Francina Munell, Unitat de Recerca Biomèdica, Institut de Recerca, Hospital Universitari Vall d'Hebron, Passeig Vall d'Hebron, 119-129, 08035 Barcelona, Spain. Fax: +34 934894015; E-mail: fmunell@ir.vhebron.net.
Abstract: Background: It is well known that estrogens regulate cell cycle progression, but the specific contributions and mechanisms of action of the estrogen receptor beta (ERβ) remain elusive. Methods: We have analyzed the levels of ERβ1 and ERβ2 throughout the cell cycle, as well as the mechanisms of action and the consequences of the over-expression of ERβ1 in the human prostate cancer LNCaP cell line. Results: Both ERβ1 mRNA and protein expression increased from the G1 to the S phase and decreased before entering the G2/M phase, whereas ERβ2 levels decreased during the S phase and increased in the G2/M phase. ERβ1 protein was detected in both the nuclear and non-nuclear fractions, and ERβ2 was found exclusively in the nucleus. Regarding the mechanisms of action, endogenous ERβ was able to activate transcription via ERE during the S phase in a ligand-dependent manner, whereas no changes in AP1 and NFκB transactivation were observed after exposure to estradiol or the specific inhibitor ICI 182,780. Over-expression of either wild type ERβ1 or ERβ1 mutated in the DNA-binding domain caused an arrest in early G1. This arrest was accompanied by the interaction of over-expressed ERβ1 with c-Jun N-terminal protein kinase 1 (JNK1) and a decrease in c-Jun phosphorylation and cyclin D1 expression. The administration of ICI impeded the JNK1–ERβ1 interaction, increased c-Jun phosphorylation and cyclin D1 expression and allowed the cells to progress to late G1, where they became arrested. Conclusions: Our results demonstrate that, in LNCaP prostate cancer cells, both ERβ isoforms are differentially expressed during the cell cycle and that ERβ regulates the G1 phase by a non-genomic mechanism.
Keywords: ERβ1, ERβ2, LNCaP, cell cycle, ERE, AP1, ICI 182,780
DOI: 10.3233/CLO-2008-0430
Journal: Analytical Cellular Pathology, vol. 30, no. 4, pp. 349-365, 2008
