Invading Basement Membrane Matrix Is Sufficient for MDA-MB-231 Breast Cancer Cells to Develop a Stable In Vivo Metastatic Phenotype

1 - ArticleIntroduction: The poor efficacy of various anti-cancer treatments against metastatic cells has focused attention on the role of tumor microenvironment in cancer progression. To understand the contribution of the extracellular matrix (ECM) environment to this phenomenon, we isolated ECM surrogate invading cell populations from MDA-MB-231 breast cancer cells and studied their genotype and malignant phenotype. Methods: We isolated invasive subpopulations (INV) from non invasive populations (REF) using a 2D-Matrigel assay, a surrogate of basal membrane passage. INV and REF populations were investigated by microarray assay and for their capacities to adhere, invade and transmigrate in vitro, and to form metastases in nude mice. Results: REF and INV subpopulations were stable in culture and present different transcriptome profiles. INV cells were characterized by reduced expression of cell adhesion and cell-cell junction genes (44% of down regulated genes) and by a gain in expression of anti-apoptotic and pro-angiogenic gene sets. In line with this observation, in vitro INV cells showed reduced adhesion and increased motility through endothelial monolayers and fibronectin. When injected into the circulation, INV cells induced metastases formation, and reduced injected mice survival by up to 80% as compared to REF cells. In nude mice, INV xenografts grew rapidly inducing vessel formation and displaying resistance to apoptosis. Conclusion: Our findings reveal that the in vitro ECM microenvironment per se was sufficient to select for tumor cells with a stable metastatic phenotype in vivo characterized by loss of adhesion molecules expression and induction of proangiogenic and survival factors

Bone marrow adipose tissue is a unique adipose subtype with distinct roles in glucose homeostasis

Bone marrow adipose tissue (BMAT) comprises >10% of total adipose mass, yet unlike white or brown adipose tissues (WAT or BAT) its metabolic functions remain unclear. Herein, we address this critical gap in knowledge. Our transcriptomic analyses revealed that BMAT is distinct from WAT and BAT, with altered glucose metabolism and decreased insulin responsiveness. We therefore tested these functions in mice and humans using positron emission tomography-computed tomography (PET/CT) with 18F-fluorodeoxyglucose. This revealed that BMAT resists insulin- and cold-stimulated glucose uptake, while further in vivo studies showed that, compared to WAT, BMAT resists insulin-stimulated Akt phosphorylation. Thus, BMAT is functionally distinct from WAT and BAT. However, in humans basal glucose uptake in BMAT is greater than in axial bones or subcutaneous WAT and can be greater than that in skeletal muscle, underscoring the potential of BMAT to influence systemic glucose homeostasis. These PET/CT studies characterise BMAT function in vivo, establish new methods for BMAT analysis, and identify BMAT as a distinct, major adipose tissue subtype

Natural killer cells distinguish innocuous and destructive forms of pancreatic islet autoimmunity

In both human patients and murine models, the progression from insulitis to diabetes is neither immediate nor inevitable, as illustrated by the innocuous versus destructive infiltrates of BDC2.5 transgenic mice on the nonobese diabetic (NOD) versus C57BL/6.H-2(g(7)) genetic backgrounds. Natural killer (NK)-cell-specific transcripts and the proportion of NK cells were increased in leukocytes from the aggressive BDC2.5/B6.H-2(g(7)) lesions. NK cell participation was also enhanced in the aggressive lesions provoked by CTLA-4 blockade in BDC2.5/NOD mice. In this context, depletion of NK cells significantly inhibited diabetes development. NOD and B6.H-2(g(7)) mice exhibit extensive variation in NK receptor expression, reminiscent of analogous human molecules. NK cells can be important players in type 1 diabetes, a role that was previously underappreciated

The circadian clock coordinates ribosome biogenesis.

Biological rhythms play a fundamental role in the physiology and behavior of most living organisms. Rhythmic circadian expression of clock-controlled genes is orchestrated by a molecular clock that relies on interconnected negative feedback loops of transcription regulators. Here we show that the circadian clock exerts its function also through the regulation of mRNA translation. Namely, the circadian clock influences the temporal translation of a subset of mRNAs involved in ribosome biogenesis by controlling the transcription of translation initiation factors as well as the clock-dependent rhythmic activation of signaling pathways involved in their regulation. Moreover, the circadian oscillator directly regulates the transcription of ribosomal protein mRNAs and ribosomal RNAs. Thus the circadian clock exerts a major role in coordinating transcription and translation steps underlying ribosome biogenesis

Vav proteins maintain epithelial traits in breast cancer cells using miR-200c-dependent and independent mechanisms

The bidirectional regulation of epithelial–mesenchymal transitions (EMT) is key in tumorigenesis. Rho GTPases regulate this process via canonical pathways that impinge on the stability of cell-to-cell contacts, cytoskeletal dynamics, and cell invasiveness. Here, we report that the Rho GTPase activators Vav2 and Vav3 utilize a new Rac1-dependent and miR-200c-dependent mechanism that maintains the epithelial state by limiting the abundance of the Zeb2 transcriptional repressor in breast cancer cells. In parallel, Vav proteins engage a mir-200c-independent expression prometastatic program that maintains epithelial cell traits only under 3D culture conditions. Consistent with this, the depletion of endogenous Vav proteins triggers mesenchymal features in epithelioid breast cancer cells. Conversely, the ectopic expression of an active version of Vav2 promotes mesenchymal-epithelial transitions using E-cadherin-dependent and independent mechanisms depending on the mesenchymal breast cancer cell line used. In silico analyses suggest that the negative Vav anti-EMT pathway is operative in luminal breast tumors. Gene signatures from the Vav-associated proepithelial and prometastatic programs have prognostic value in breast cancer patients.Fil: Lorenzo Martín, L. Francisco. Universidad de Salamanca; España. Consejo Superior de Investigaciones Científicas; España. Instituto de Biología Molecular y Celular del Cáncer de Salamanca; EspañaFil: Citterio, Carmen. Consejo Superior de Investigaciones Científicas; España. Instituto de Biología Molecular y Celular del Cáncer de Salamanca; EspañaFil: Menacho Márquez, Mauricio Ariel. Universidad de Salamanca; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario. Universidad Nacional de Rosario. Instituto de Investigaciones para el Descubrimiento de Fármacos de Rosario; Argentina. Instituto de Biología Molecular y Celular del Cáncer de Salamanca; EspañaFil: Conde, Javier. Consejo Superior de Investigaciones Científicas; España. Instituto de Biología Molecular y Celular del Cáncer de Salamanca; EspañaFil: Larive, Romain M.. Consejo Superior de Investigaciones Científicas; España. Institut Des Biomolécules Max Mousseron; FranciaFil: Rodríguez Fdez, Sonia. Consejo Superior de Investigaciones Científicas; EspañaFil: García Escudero, Ramón. Consejo Superior de Investigaciones Científicas; España. Universidad de Salamanca; EspañaFil: Robles Valero, Javier. Universidad de Salamanca; España. Consejo Superior de Investigaciones Científicas; España. Centro de Investigación del Cáncer; España. Instituto de Biología Molecular y Celular del Cáncer de Salamanca; EspañaFil: Cuadrado, Myriam. Universidad de Salamanca; España. Instituto de Biología Molecular y Celular del Cáncer de Salamanca; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Fernández Pisonero, Isabel. Universidad de Salamanca; España. Consejo Superior de Investigaciones Científicas; España. Instituto de Biología Molecular y Celular del Cáncer de Salamanca; EspañaFil: Dosil, Mercedes. Universidad de Salamanca; España. Consejo Superior de Investigaciones Científicas; España. Instituto de Biología Molecular y Celular del Cáncer de Salamanca; EspañaFil: Sevilla, María A.. Universidad de Salamanca; EspañaFil: Montero, María J.. Universidad de Salamanca; EspañaFil: Fernández Salguero, Pedro. Universidad de Extremadura; EspañaFil: Paramio, Jesús M.. Universidad de Salamanca; España. Consejo Superior de Investigaciones Científicas; España. Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas; EspañaFil: Bustelo, Xosé R.. Universidad de Salamanca; España. Consejo Superior de Investigaciones Científicas; Españ