title: The estrogen receptor alpha-derived peptide ERα17p (P(295)-T(311)) exerts pro-apoptotic actions in breast cancer cells in vitro and in vivo, independently from their ERα status.
abstract: In recent years, our knowledge on estrogen receptors (ER) has been modified profoundly with the identification and the deciphering of the role of its protein effectors, as well as with the deeper insight of its molecular structure/function dynamics, characteristics associated with its nucleo-cytoplasmic-membrane shuttling properties. Also, significant progress has been made concerning its turn-over and associated final proteasomal degradation processes. These advances could lead in the near future to the design and the synthesis of novel receptor-interacting drugs. Recently, a number of receptor-related peptides acting as specific ER ligands have been identified and extensively studied with respect to their estrogenic/antiestrogenic activities. Among them, ERα17p, a synthetic analog of the P(295)-T(311) sequence of ERα, has been shown to exert pseudo-estrogenic effects by interacting in the close vicinity of its hinge region (BF3 domain). Remarkably, this sequence appears as the epicenter of a number of post-transcriptional modifications as well as of the recruitment of co-regulators, suggesting that it would play a key role in ERα functions. Here, we provide evidence that ERα17p induces apoptosis in ERα-positive (MCF-7, T47D) and -negative (MDA-MB-231, SK-BR-3) breast cancer cells by an ERα-independent membrane mechanism, triggering major pro-apoptotic signaling cascades. Finally, ERα17p induces the regression of breast ERα-negative cancer tumor xenografts, without apparent toxicity, suggesting that it could represent a new attractive tool for the development of future promising therapeutic approaches, and providing a novel insight to ER regulation of cell fate.
authors.affiliation: Laboratory of Experimental Endocrinology, University of Crete, School of Medicine, P.O. Box 2208, Heraklion 71003, Greece.
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Pelekanou
authors.forename: Marilena
authors.initials: M
authors.lastname: Kampa
authors.forename: Dominique
authors.initials: D
authors.lastname: Gallo
authors.forename: George
authors.initials: G
authors.lastname: Notas
authors.forename: Maria
authors.initials: M
authors.lastname: Troullinaki
authors.forename: Hugues
authors.initials: H
authors.lastname: Duvillier
authors.forename: Yves
authors.initials: Y
authors.lastname: Jacquot
authors.forename: Efstathios N
authors.initials: EN
authors.lastname: Stathopoulos
authors.forename: Elias
authors.initials: E
authors.lastname: Castanas
authors.forename: Guy
authors.initials: G
authors.lastname: Leclercq
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010455:Peptides / Q000502:physiology*
chemical_list: D047628:Estrogen Receptor alpha; D010455:Peptides