Análisis de la distribución de tamaño de los cristales de glaucofana en los esquistos azules de Jambaló

Las texturas junto a la geoquímica de la roca quedan registradas dentro de los granos minerales que se desarrollan en esta, permitiendo analizar y entender los procesos geológicos evolutivos ocurridos en un área. Las rocas metamórficas de alta presión asociadas a zonas de subducción pueden desarrollar minerales índices para dichas condiciones como la glaucofana, granate, circón, rutilo y esfena, a partir de diversos mecanismos como milonitización entre rocas de diferente litología y rocas con alto contenido en SiO2. Los esquistos azules de Jambaló muestran condiciones tectónicas, geoquímicas y trayectorias de cristalización que permiten el desarrollo de esta mineralogía. El análisis de la distribución de tamaño de grano permitió definir los diferentes estadios de cristalización para las glaucofanas y asociarlas a un modelo de zona de subducción de arco de isla que se produjo durante el cretácico tardío

Role of the androgen receptor in breast cancer and preclinical analysis of enzalutamide

INTRODUCTION: The androgen receptor (AR) is widely expressed in breast cancers and has been proposed as a therapeutic target in estrogen receptor alpha (ER) negative breast cancers that retain AR. However, controversy exists regarding the role of AR, particularly in ER + tumors. Enzalutamide, an AR inhibitor that impairs nuclear localization of AR, was used to elucidate the role of AR in preclinical models of ER positive and negative breast cancer. METHODS: We examined nuclear AR to ER protein ratios in primary breast cancers in relation to response to endocrine therapy. The effects of AR inhibition with enzalutamide were examined in vitro and in preclinical models of ER positive and negative breast cancer that express AR. RESULTS: In a cohort of 192 women with ER + breast cancers, a high ratio of AR:ER (≥2.0) indicated an over four fold increased risk for failure while on tamoxifen (HR = 4.43). The AR:ER ratio had an independent effect on risk for failure above ER % staining alone. AR:ER ratio is also an independent predictor of disease-free survival (HR = 4.04, 95% CI: 1.68, 9.69; p = 0.002) and disease specific survival (HR = 2.75, 95% CI: 1.11, 6.86; p = 0.03). Both enzalutamide and bicalutamide inhibited 5-alpha-dihydrotestosterone (DHT)-mediated proliferation of breast cancer lines in vitro; however, enzalutamide uniquely inhibited estradiol (E2)-mediated proliferation of ER+/AR + breast cancer cells. In MCF7 xenografts (ER+/AR+) enzalutamide inhibited E2-driven tumor growth as effectively as tamoxifen by decreasing proliferation. Enzalutamide also inhibited DHT- driven tumor growth in both ER positive (MCF7) and negative (MDA-MB-453) xenografts, but did so by increasing apoptosis. CONCLUSIONS: AR to ER ratio may influence breast cancer response to traditional endocrine therapy. Enzalutamide elicits different effects on E2-mediated breast cancer cell proliferation than bicalutamide. This preclinical study supports the initiation of clinical studies evaluating enzalutamide for treatment of AR(+) tumors regardless of ER status, since it blocks both androgen- and estrogen- mediated tumor growth

Autophagy Counterbalances Endoplasmic Reticulum Expansion during the Unfolded Protein Response

The protein folding capacity of the endoplasmic reticulum (ER) is regulated by the unfolded protein response (UPR). The UPR senses unfolded proteins in the ER lumen and transmits that information to the cell nucleus, where it drives a transcriptional program that is tailored to re-establish homeostasis. Using thin section electron microscopy, we found that yeast cells expand their ER volume at least 5-fold under UPR-inducing conditions. Surprisingly, we discovered that ER proliferation is accompanied by the formation of autophagosome-like structures that are densely and selectively packed with membrane stacks derived from the UPR-expanded ER. In analogy to pexophagy and mitophagy, which are autophagic processes that selectively sequester and degrade peroxisomes and mitochondria, the ER-specific autophagic process described utilizes several autophagy genes: they are induced by the UPR and are essential for the survival of cells subjected to severe ER stress. Intriguingly, cell survival does not require vacuolar proteases, indicating that ER sequestration into autophagosome-like structures, rather than their degradation, is the important step. Selective ER sequestration may help cells to maintain a new steady-state level of ER abundance even in the face of continuously accumulating unfolded proteins

Intracellular signaling by the unfolded protein response

Abstract The unfolded protein response (UPR) is an intracellular signaling pathway that is activated by the accumulation of unfolded proteins in the endoplasmic reticulum (ER). UPR activation triggers an extensive transcriptional response, which adjusts the ER protein folding capacity according to need. As such, the UPR constitutes a paradigm of an intracellular control mechanism that adjusts organelle abundance in response to environmental or developmental clues. The pathway involves activation of ER unfolded protein sensors that operate in parallel circuitries to transmit information across the ER membrane, activating a set of downstream transcription factors by mechanisms that are unusual yet rudimentarily conserved in all eukaryotes. Recent results shed light on the mechanisms by which unfolded proteins are sensed in the ER and by which the unfolded protein signals are relayed and integrated to reestablish homeostasis in the cell's protein folding capacity or-if this cannot be achievedcommit cells to apoptosis

Role of dopamine in the physiology of T-cells and dendritic cells.

Dendritic cells (DCs) are responsible for priming T-cells and for promoting their differentiation from naïve T-cells into appropriate effector cells. Because of their fundamental roles in controlling immunity, DCs and T-cells require tight regulatory mechanisms. Several studies have shown that dopamine, not only mediate interactions into the nervous system, but can also contribute to the modulation of immunity. Here, we review the emerging role of this neurotransmitter as a regulator of DC and T-cell physiology and, in turn, immune response. Moreover, we discuss how alterations in the dopamine-mediated immune regulatory mechanisms could contribute to the onset of immune-related disorders