Breast primary epithelial cells that escape p16-dependent stasis enter a telomere-driven crisis state
Feijoo, Purificación (Universitat Autònoma de Barcelona. Departament de Biologia Cel·lular, de Fisiologia i d'Immunologia)
Terradas, Mariona (Universitat Autònoma de Barcelona. Departament de Biologia Cel·lular, de Fisiologia i d'Immunologia)
Soler, David (Universitat Autònoma de Barcelona. Departament de Biologia Cel·lular, de Fisiologia i d'Immunologia)
Domínguez, Daniel (Universitat Autònoma de Barcelona. Departament de Biologia Cel·lular, de Fisiologia i d'Immunologia)
Tusell Padrós, Laura (Universitat Autònoma de Barcelona. Departament de Biologia Cel·lular, de Fisiologia i d'Immunologia)
Genescà, Anna (Anna) (Universitat Autònoma de Barcelona. Departament de Biologia Cel·lular, de Fisiologia i d'Immunologia)

Fecha:	2016
Resumen:	Breast cancer is the most common malignant disease in women, but some basic questions remain in breast cancer biology. To answer these, several cell models were developed. Recently, the use of improved cell-culture conditions has enabled the development of a new primary cell model with certain luminal characteristics. This model is relevant because, after the introduction of a specific set of genetic elements, the transformed cells yielded tumors resembling human adenocarcinomas in mice. The use of improved cell-culture conditions supporting the growth of these breast primary epithelial cells was expected to delay or eliminate stress-induced senescence and lead to the propagation of normal cells. However, no studies have been carried out to investigate these points. Propagation of breast primary epithelial cells was performed in WIT medium on Primaria plates. Immunofluorescence, western blot and qRT-PCR were used to detect molecular markers, and to determine the integrity of DNA damage-response pathways. Promoter methylation of p16 INK4a was assessed by pyrosequencing. In order to obtain a dynamic picture of chromosome instability over time in culture, we applied FISH methodologies. To better link chromosome instability with excessive telomere attrition, we introduced the telomerase reverse transcriptase human gene using a lentiviral vector. We report here that breast primary epithelial cells propagated in vitro with WIT medium on Primaria plates express some luminal characteristics, but not a complete luminal lineage phenotype. They undergo a p16-dependent stress-induced senescence (stasis), and the cells that escape stasis finally enter a crisis state with rampant chromosome instability. Chromosome instability in these cells is driven by excessive telomere attrition, as distributions of chromosomes involved in aberrations correlate with the profiles of telomere signal-free ends. Importantly, ectopic expression of the human TERT gene rescued their chromosomal instability phenotype. Essentially, our data show that contrary to what was previously suggested, improved culture conditions to propagate in vitro mammary epithelial cells with some luminal characteristics do not prevent stress-induced senescence. This barrier is overcome by spontaneous methylation of the p16 INK4a promoter, allowing the proliferation of cells with telomere dysfunction and ensuing chromosome instability.
Ayudas:	Ministerio de Economía y Competitividad SAF2013-43801-P Ministerio de Economía y Competitividad 2013FI-B200186 Ministerio de Economía y Competitividad 2013FI-B200188
Derechos:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	Mammary epithelial cells ; Breast cancer ; Telomeres ; Chromosome instability
Publicado en:	Breast cancer research, Vol. 18 (January 2016) , art. 7, ISSN 1465-542X

DOI: 10.1186/s13058-015-0667-z
PMID: 26758019

13 p, 2.7 MB

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