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Cortes M.A.,University of Alcala | Cariaga-Martinez A.E.,University of Alcala | Lobo M.V.T.,University of Alcala | Lobo M.V.T.,Instituto Ramon Y Cajal Of Investigaciones Sanitarias | And 7 more authors.
Carcinogenesis | Year: 2012

An increased neuroendocrine (NE) cell population in prostate cancer is associated with more aggressive disease and recurrence after androgen-deprivation therapy, although the mechanism responsible is unknown. In this study, we report that the treatment of LNCaP cells with epidermal growth factor (EGF) in the presence of LY294002, an inhibitor of the phosphoinositol 3'-kinase (PI3K)-AKT pathway, induced an increase of levels and activity of ErbB2. Under these conditions, we also observed cell survival and NE differentiation. When we treated with wortmannin, another PI3K inhibitor, or we knocked down PI3K or AKT isoforms in the presence of EGF, ErbB2 up-regulation was not observed, suggesting that the increase of ErbB2 induced by EGF plus LY294002 is not mediated by the PI3K-Akt pathway. Other targets of LY294002 were also discounted. We also show that ErbB2 up-regulation is directly involved in neuroendocine differentiation but not in cell survival as ErbB2 levels increased in parallel with NE differentiation marker levels, whereas ErbB2 knockdown reduced them; other NE differentiation inducers also increased the ErbB2 levels and the immunohistochemical analysis of prostate cancer samples showed colocalization of ErbB2 and chromogranin A. We found that, in LNCaP cells, EGF in combination with LY294002 increased ErbB2 levels by a PI3K/AKT-independent mechanism and that this increase was associated with the acquisition of a NE phenotype. These results suggest that is worth reconsidering ErbB2 as a drug target in prostate cancer and this should be kept in mind when designing new clinical schedules for the treatment of this disease. © The Author 2012. Published by Oxford University Press. All rights reserved.

Bejarano E.,Yeshiva University | Rodriguez-Navarro J.A.,Yeshiva University | Rodriguez-Navarro J.A.,Instituto Ramon Y Cajal Of Investigaciones Sanitarias
Amino Acids | Year: 2014

Autophagy is a catabolic pathway responsible for the maintenance of the tissue and organism homeostasis. Several amino acids regulate autophagic activity in different tissues, such as liver and muscle, but much less is known about this regulation in the brain. The lack of autophagy in neurons leads to a strong neurodegenerative phenotype and epileptic disorders. We summarize the current knowledge about the regulation of autophagy mediated by amino acids and how macroautophagy could serve as source of amino acids. We review the contribution of macroautophagy in the brain physiology and pathology emphasizing the relevancy of the proper control of amino acid levels such as glutamate and GABA in the brain due to its role as neurotransmitters and energy source. Furthermore, we discuss how malfunction in autophagy may result in pathological consequences, because many genetic epileptic disorders are related to signaling or metabolic pathways controlling both macroautophagy and amino acid metabolism in the brain. © 2014 Springer-Verlag Wien.

Cariaga-Martinez A.E.,University of Alcala | Lopez-Ruiz P.,University of Alcala | Nombela-Blanco M.P.,University of Alcala | Motino O.,University of Alcala | And 6 more authors.
Cellular Signalling | Year: 2013

AKT isoforms are expressed in prostate cancer and their expression and localization have different associations with clinical characteristics. However, the distinct roles of the AKT isoforms in prostate cancer cells are largely unknown. In the present study, we demonstrate distinct roles for AKT1 and AKT2 in cell growth and migration. Ablation of AKT1 and AKT2 decreased the proliferation of the androgen-independent cell line PC-3, although by different mechanisms. AKT1 ablation induced loss of cell adhesion and subsequent apoptosis. AKT2 (but not AKT1) ablation promoted cell cycle arrest at G0/G1, associated with downregulation of cyclin D, CDK6 and CDK2, and upregulation and cytoplasmic-to-nuclear redistribution of p27. The increase of p27 protein levels was due to more gene transcription and an increase in protein stability. The increased stability of p27 was induced by delocalisation of Skp2 and a lower level of p27 phosphorylation at Thr187. AKT1 and AKT2 ablation inhibited and stimulated PC-3 cell migration, respectively. An AKT isoform-specific function could be associated with its subcellular localization. We found that AKT1 and AKT2 were mainly localised in the cytoplasm and nucleus, respectively. In androgen-sensitive cell line LNCaP, the ablation of AKT1 or AKT2 caused apoptosis but in androgen-independent LNCaP sublines, the effect of AKT1 ablation was lower; whereas no changes were observed after AKT2 ablation. Taken together, our data show that AKT1 and AKT2 have non-redundant roles in the regulation of PC-3 cell proliferation and migration. These could be explained by their subcellular localization and/or the specific regulation of downstream effectors. Furthermore, contribution of AKT isoforms to the progression of prostate cancer may change from an androgen-sensitive to a hormone-refractory stage. These findings may help design new targeted strategies for inhibiting AKT isoforms in prostate cancer. © 2013 Elsevier Inc.

Fernandez-Pinar P.,Complutense University of Madrid | Fernandez-Pinar P.,Instituto Ramon Y Cajal Of Investigaciones Sanitarias | Aleman A.,Complutense University of Madrid | Aleman A.,Instituto Ramon Y Cajal Of Investigaciones Sanitarias | And 6 more authors.
Molecular Biology of the Cell | Year: 2012

Intracellular survival of Salmonella relies on the activity of proteins translocated into the host cell by type III secretion systems (T3SS). The protein kinase activity of the T3SS effector SteC is required for F-actin remodeling in host cells, although no SteC target has been identified so far. Here we show that expression of the N-terminal non-kinase domain of SteC down-regulates the mating and HOG pathways in Saccharomyces cerevisiae. Epistasis analyses using constitutively active components of these pathways indicate that SteC inhibits signaling at the level of the GTPase Cdc42. We demonstrate that SteC interacts through its N-terminal domain with the catalytic domain of Cdc24, the sole S. cerevisiae Cdc42 guanine nucleotide exchange factor (GEF). SteC also binds to the human Cdc24-like GEF protein Vav1. Moreover, expression of human Cdc42 suppresses growth inhibition caused by SteC. Of interest, the N-terminal SteC domain alters Cdc24 cellular localization, preventing its nuclear accumulation. These data reveal a novel functional domain within SteC, raising the possibility that this effector could also target GTPase function in mammalian cells. Our results also highlight the key role of the Cdc42 switch in yeast mating and HOG pathways and provide a new tool to study the functional consequences of Cdc24 localization. © 2012 Fernandez-Piñar et al.

Fortun J.,Instituto Ramon Y Cajal Of Investigaciones Sanitarias | Meije Y.,Instituto Ramon Y Cajal Of Investigaciones Sanitarias | Peman J.,Polytechnic University of Valencia | Perez M.,Fontlab2000 | And 7 more authors.
The Journal of antimicrobial chemotherapy | Year: 2014

BACKGROUND: New techniques, such as those based on multiplex quantitative real-time PCR (MRT-PCR), can improve the detection of invasive candidiasis (IC).METHODS: We prospectively studied 63 intensive care unit patients with suspected IC and 40 healthy controls. Blood cultures and MRT-PCR were performed at day 0 and +2, +7, +14 and +21 days in all patients. In addition, β-d-glucan (BDG) and Candida albicans germ tube antibody (CAGTA) were quantified.RESULTS: IC was confirmed in 27 patients. Colonization was significantly higher in patients with IC (96% versus 64%, P = 0.002). The sensitivity, specificity, positive predictive value and negative predictive value of MRT-PCR for the diagnosis of IC were 96.3%, 97.3%, 92.8% and 98.7%, respectively. The positive predictive value and specificity were significantly higher for MRT-PCR than for BDG and CATGA. MRT-PCR performed very well, especially in deep-seated IC (sensitivity 90.9% versus 45.4% for blood culture; P = 0.06). As regards the most appropriate clinical sample for DNA amplification, in this study whole blood and serum presented similar results.CONCLUSIONS: MRT-PCR appears to be a useful test for confirming a diagnosis of IC in critically ill patients, especially in those with deep-seated disease. Its high sensitivity and positive predictive value make it a much more efficient tool for the management of IC than other diagnostic procedures and clinical scores. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

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