RESUMEN
The tumour stroma is believed to contribute to some of the most malignant characteristics of epithelial tumours. However, signalling between stromal and tumour cells is complex and remains poorly understood. Here we show that the genetic inactivation of Pten in stromal fibroblasts of mouse mammary glands accelerated the initiation, progression and malignant transformation of mammary epithelial tumours. This was associated with the massive remodelling of the extracellular matrix (ECM), innate immune cell infiltration and increased angiogenesis. Loss of Pten in stromal fibroblasts led to increased expression, phosphorylation (T72) and recruitment of Ets2 to target promoters known to be involved in these processes. Remarkably, Ets2 inactivation in Pten stroma-deleted tumours ameliorated disruption of the tumour microenvironment and was sufficient to decrease tumour growth and progression. Global gene expression profiling of mammary stromal cells identified a Pten-specific signature that was highly represented in the tumour stroma of patients with breast cancer. These findings identify the Pten-Ets2 axis as a critical stroma-specific signalling pathway that suppresses mammary epithelial tumours.
Asunto(s)
Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Fibroblastos/metabolismo , Neoplasias Glandulares y Epiteliales/metabolismo , Neoplasias Glandulares y Epiteliales/patología , Fosfohidrolasa PTEN/metabolismo , Células del Estroma/metabolismo , Animales , Línea Celular Tumoral , Proliferación Celular , Transformación Celular Neoplásica , Matriz Extracelular/metabolismo , Eliminación de Gen , Regulación Neoplásica de la Expresión Génica , Humanos , Inmunidad Innata , Neoplasias Mamarias Experimentales/metabolismo , Neoplasias Mamarias Experimentales/patología , Ratones , Ratones Transgénicos , Fosfohidrolasa PTEN/deficiencia , Fosfohidrolasa PTEN/genética , Proteína Proto-Oncogénica c-ets-2/deficiencia , Proteína Proto-Oncogénica c-ets-2/metabolismoRESUMEN
The ras/Raf/Mek/Erk pathway plays a central role in coordinating endothelial cell activities during angiogenesis. Transcription factors Ets1 and Ets2 are targets of ras/Erk signaling pathways that have been implicated in endothelial cell function in vitro, but their precise role in vascular formation and function in vivo remains ill-defined. In this work, mutation of both Ets1 and Ets2 resulted in embryonic lethality at midgestation, with striking defects in vascular branching having been observed. The action of these factors was endothelial cell autonomous as demonstrated using Cre/loxP technology. Analysis of Ets1/Ets2 target genes in isolated embryonic endothelial cells demonstrated down-regulation of Mmp9, Bcl-X(L), and cIAP2 in double mutants versus controls, and chromatin immunoprecipitation revealed that both Ets1 and Ets2 were loaded at target promoters. Consistent with these observations, endothelial cell apoptosis was significantly increased both in vivo and in vitro when both Ets1 and Ets2 were mutated. These results establish essential and overlapping functions for Ets1 and Ets2 in coordinating endothelial cell functions with survival during embryonic angiogenesis.
Asunto(s)
Apoptosis/genética , Desarrollo Embrionario/genética , Células Endoteliales/citología , Regulación del Desarrollo de la Expresión Génica/fisiología , Neovascularización Fisiológica/genética , Proteína Proto-Oncogénica c-ets-1/fisiología , Proteína Proto-Oncogénica c-ets-2/fisiología , Animales , Vasos Sanguíneos/embriología , Vasos Sanguíneos/ultraestructura , Supervivencia Celular/genética , Quimera , Edema/embriología , Edema/genética , Transferencia de Embrión , Muerte Fetal/genética , Muerte Fetal/patología , Enfermedades Fetales/genética , Enfermedades Fetales/patología , Regulación del Desarrollo de la Expresión Génica/genética , Vectores Genéticos/genética , Vectores Genéticos/farmacología , Hemorragia/embriología , Hemorragia/genética , Homocigoto , Ratones , Ratones Noqueados , Fenotipo , Proteína Proto-Oncogénica c-ets-1/deficiencia , Proteína Proto-Oncogénica c-ets-1/genética , Proteína Proto-Oncogénica c-ets-2/deficiencia , Proteína Proto-Oncogénica c-ets-2/genéticaRESUMEN
The ETS-family transcription factors Ets1 and Ets2 are evolutionarily conserved effectors of the RAS/ERK signaling pathway, but their function in Ras cellular transformation and biology remains unclear. Taking advantage of Ets1 and Ets2 mouse models to generate Ets1/Ets2 double knockout mouse embryonic fibroblasts, we demonstrate that deletion of both Ets1 and Ets2 was necessary to inhibit HrasG12V induced transformation both in vitro and in vivo. HrasG12V expression in mouse embryonic fibroblasts increased ETS1 and ETS2 expression and binding to cis-regulatory elements on the c-Myc proximal promoter, and consequently induced a robust increase in MYC expression. The expression of the oncogenic microRNA 17-92 cluster was increased in HrasG12V transformed cells, but was significantly reduced when ETS1 and ETS2 were absent. MYC and ETS1 or ETS2 collaborated to increase expression of the oncogenic microRNA 17-92 cluster in HrasG12V transformed cells. Enforced expression of exogenous MYC or microRNA 17-92 rescued HrasG12V transformation in Ets1/Ets2-null cells, revealing a direct function for MYC and microRNA 17-92 in ETS1/ETS2-dependent HrasG12V transformation.