Intracellular Autofluorescence as a New Biomarker for Cancer Stem Cells in Glioblastoma.

The identification of cancer stem cells (CSCs), which are implicated in tumor initiation, progression, therapy resistance, and relapse, is of great biological and clinical relevance. In glioblastoma (GBM), this is still a challenge, as no single marker is able to universally identify populations of GBM cancer stem cells (GSCs). Indeed, there is still controversy on whether biomarker-expressing cells fulfill the functional criteria of bona fide GSCs, despite being widely used. Here, we describe a novel subpopulation of autofluorescent (Fluo+) cells in GBM that bear all the functional characteristics of GSCs, including higher capacity to grow as neurospheres, long-term self-renewal ability, increased expression of stem cell markers, and enhanced in vivo tumorigenicity. Mechanistically, the autofluorescent phenotype is largely due to the intracellular accumulation of riboflavin, mediated by the ABC transporter ABCG2. In summary, our work identifies an intrinsic cellular autofluorescent phenotype enriched in GBM cells with functional stem cells features that can be used as a novel, simple and reliable biomarker to target these highly malignant tumors, with implications for GBM biological and clinical research.

Sweet Selenium: Synthesis and Properties of Selenium-Containing Sugars and Derivatives.

In the last decades, organoselenium compounds gained interest due to their important biological features. However, the lack of solubility, which characterizes most of them, makes their actual clinical exploitability a hard to reach goal. Selenosugars, with their intrinsic polarity, do not suffer from this issue and as a result, they can be conceived as a useful alternative. The aim of this review is to provide basic knowledge of the synthetic aspects of selenosugars, selenonium salts, selenoglycosides, and selenonucleotides. Their biological properties will be briefly detailed. Of course, it will not be a comprehensive dissertation but an analysis of what the authors think is the cream of the crop of this interesting research topic.

Helicobacter pylori seroprevalence in Spain: influence of adult and childhood sociodemographic factors.

Helicobacter pylori (H. pylori) chronic infection causes severe digestive diseases, including gastric cancer, and certain strains entail a higher risk. Risk factors for this infection are still not fully understood. The aim of this study was to describe the association of adult and childhood sociodemographic factors with the seroprevalence of H. pylori, and with CagA and VacA antigen-specific seropositivity among H. pylori-seropositive individuals in the Spanish adult population. Serum antibody reactivity to H. pylori proteins was evaluated using multiplex serology in 2555 population-based controls enrolled in the MCC-Spain study, a multicase-control study recruiting participants from 2008 to 2013 in different areas of Spain. H. pylori seroprevalence was defined as seropositivity against at least four bacterial proteins. Information on sociodemographics, lifestyles, and environmental exposures was collected through personal interviews. Prevalence ratios and 95% confidence intervals were estimated using Poisson regression models to assess the association of lifetime sociodemographic factors with H. pylori seroprevalence and with seropositivity for CagA and VacA. H. pylori seroprevalence was 87.2%. Seropositivity was statistically significantly higher in men, increased with age, BMI, and number of siblings, and decreased with education and socioeconomic family level at birth. Among H. pylori-seropositive individuals, seropositivity was 53.3% for CagA, 61.4% for VacA, and 38.8% for both CagA and VacA. Ever smokers had lower seroprevalence for CagA and VacA than never smokers. H. pylori seroprevalence among this Spanish adult population was high and one third of the population was seropositive for two well-known markers of gastric cancer risk: CagA and VacA. Sex, age, education, and BMI were associated with H. pylori seroprevalence.

Inventario de síntomas prefrontales (ISP): validez ecológica y convergencia con medidas neuropsicológicas / Prefrontal Symptoms Inventory (PSI): ecological validity and convergence with neuropsychological measures

Introducción. El inventario de síntomas prefrontales (ISP) es un cuestionario autoinformado creado en España que interroga sobre alteraciones cognitivas, emocionales y comportamentales en las actividades de la vida diaria y que resulta aplicable tanto en población general como en múltiples poblaciones clínicas. Existe una versión abreviada de 20 ítems (ISP-20) con excelentes propiedades psicométricas para el cribado. Objetivo. Estudiar la validez convergente y divergente del ISP e ISP-20, analizando cómo sus escalas reflejan las consecuencias cotidianas de déficits reales hallados en evaluación neuropsicológica mediante pruebas de ejecución. Pacientes y métodos. Se estudiaron 52 personas con adicción a sustancias en tratamiento (31 varones y 21 mujeres) a las que se administró el ISP junto con una batería de exploración neuropsicológica abreviada centrada en describir procesos atencionales, mnémicos y ejecutivos. Resultados. Ambas versiones del ISP presentan óptimas propiedades psicométricas (0,78 > alfa > 0,94 para la versión completa de 46 ítems y 0,7 > alfa > 0,89 para la versión abreviada de 20 ítems). Los resultados confirman las hipótesis sobre su validez: la escala de problemas en la ejecución se relaciona con la capacidad para resolver tests que presumiblemente valoran funciones ejecutivas de origen prefrontal (validez convergente), mientras que las escalas de problemas en el control emocional y problemas en la conducta social no se relacionan con dichas capacidades cognitivas (validez discriminante). Conclusiones. El ISP es una prueba clínicamente útil, psicométricamente válida y aplicable en múltiples poblaciones clínicas (AU)

Introduction. The Prefrontal Symptoms Inventory (PSI) is a self-reported questionnaire, created in Spain, which asks about cognitive, emotional and behavioural alterations in activities of daily living and which can be applied in both the general population and in multiple clinical populations. There is a shorter 20-item version (PSI-20) with excellent psychomotor properties for screening. Aim. To study the convergent and divergent validity of the PSI and PSI-20, by analysing how their scales reflect the day-today consequences of real deficits found in neurological assessment performed by means of performance tests. Patients and methods. A sample of 52 persons undergoing treatment for substance addiction (31 males and 21 females) were administered the PSI together with an abbreviated neuropsychological examination battery focused on describing attentional, mnemonic and executive processes. Results. Both versions of the PSI present optimal psychometric properties (0.78 > alpha > 0.94 for the complete 46-item version and 0.7 > alpha > 0.89 for the abbreviated 20-item version). The results confirm the hypotheses regarding their validity: the performance problems scale is related with the capacity to resolve tests that supposedly rate the executive functions of a prefrontal origin (convergent validity), whereas the scales of problems in emotional control and problems with social behaviour are not related with those cognitive capabilities (discriminant validity). Conclusions. The PSI is a test that is clinically useful, psychometrically valid and applicable in multiple clinical populations (AU)

The miR-17-92 cluster counteracts quiescence and chemoresistance in a distinct subpopulation of pancreatic cancer stem cells.

OBJECTIVE: Cancer stem cells (CSCs) represent the root of many solid cancers including pancreatic ductal adenocarcinoma, are highly chemoresistant and represent the cellular source for disease relapse. However the mechanisms involved in these processes still need to be fully elucidated. Understanding the mechanisms implicated in chemoresistance and metastasis of pancreatic cancer is critical to improving patient outcomes. DESIGN: Micro-RNA (miRNA) expression analyses were performed to identify functionally defining epigenetic signatures in pancreatic CSC-enriched sphere-derived cells and gemcitabine-resistant pancreatic CSCs. RESULTS: We found the miR-17-92 cluster to be downregulated in chemoresistant CSCs versus non-CSCs and demonstrate its crucial relevance for CSC biology. In particular, overexpression of miR-17-92 reduced CSC self-renewal capacity, in vivo tumourigenicity and chemoresistance by targeting multiple NODAL/ACTIVIN/TGF-ß1 signalling cascade members as well as directly inhibiting the downstream targets p21, p57 and TBX3. Overexpression of miR-17-92 translated into increased CSC proliferation and their eventual exhaustion via downregulation of p21 and p57. Finally, the translational impact of our findings could be confirmed in preclinical models for pancreatic cancer. CONCLUSIONS: Our findings therefore identify the miR-17-92 cluster as a functionally determining family of miRNAs in CSCs, and highlight the putative potential of developing modulators of this cluster to overcome drug resistance in pancreatic CSCs.

Microenvironmental hCAP-18/LL-37 promotes pancreatic ductal adenocarcinoma by activating its cancer stem cell compartment.

OBJECTIVES: The tumour stroma/microenvironment not only provides structural support for tumour development, but more importantly it provides cues to cancer stem cells (CSCs) that regulate their self-renewal and metastatic potential. This is certainly true for pancreatic ductal adenocarcinomas (PDAC), where tumour-associated fibroblasts, pancreatic stellate cells and immune cells create an abundant paracrine niche for CSCs via microenvironment-secreted factors. Thus understanding the role that tumour stroma cells play in PDAC development and CSC biology is of utmost importance. DESIGN: Microarray analyses, tumour microarray immunohistochemical assays, in vitro co-culture experiments, recombinant protein treatment approaches and in vivo intervention studies were performed to understand the role that the immunomodulatory cationic antimicrobial peptide 18/LL-37 (hCAP-18/LL-37) plays in PDAC biology. RESULTS: We found that hCAP-18/LL-37 was strongly expressed in the stroma of advanced primary and secondary PDAC tumours and is secreted by immune cells of the stroma (eg, tumour-associated macrophages) in response to tumour growth factor-ß1 and particularly CSC-secreted Nodal/ActivinA. Treatment of pancreatic CSCs with recombinant LL-37 increased pluripotency-associated gene expression, self-renewal, invasion and tumourigenicity via formyl peptide receptor 2 (FPR2)- and P2X purinoceptor 7 receptor (P2X7R)-dependent mechanisms, which could be reversed by inhibiting these receptors. Importantly, in a genetically engineered mouse model of K-Ras-driven pancreatic tumourigenesis, we also showed that tumour formation was inhibited by either reconstituting these mice with bone marrow from cathelicidin-related antimicrobial peptide (ie, murine homologue of hCAP-18/LL-37) knockout mice or by pharmacologically inhibiting FPR2 and P2X7R. CONCLUSIONS: Thus, hCAP-18/LL-37 represents a previously unrecognised PDAC microenvironment factor that plays a critical role in pancreatic CSC-mediated tumourigenesis.

Intracellular autofluorescence: a biomarker for epithelial cancer stem cells.

Cancer stem cells (CSCs) are thought to drive tumor growth, metastasis and chemoresistance. Although surface markers such as CD133 and CD44 have been successfully used to isolate CSCs, their expression is not exclusively linked to the CSC phenotype and is prone to environmental alteration. We identified cells with an autofluorescent subcellular compartment that exclusively showed CSC features across different human tumor types. Primary tumor-derived autofluorescent cells did not overlap with side-population (SP) cells, were enriched in sphere culture and during chemotherapy, strongly expressed pluripotency-associated genes, were highly metastatic and showed long-term in vivo tumorigenicity, even at the single-cell level. Autofluorescence was due to riboflavin accumulation in membrane-bounded cytoplasmic structures bearing ATP-dependent ABCG2 transporters. In summary, we identified and characterized an intrinsic autofluorescent phenotype in CSCs of diverse epithelial cancers and used this marker to isolate and characterize these cells.

Chloroquine targets pancreatic cancer stem cells via inhibition of CXCR4 and hedgehog signaling.

Pancreatic ductal adenocarcinoma is one of the deadliest carcinomas and is characterized by highly tumorigenic and metastatic cancer stem cells (CSC). CSCs evade available therapies, which preferentially target highly proliferative and more differentiated progenies, leaving behind CSCs as a putative source for disease relapse. Thus, to identify potentially more effective treatment regimens, we screened established and new compounds for their ability to eliminate CSCs in primary pancreatic cancer (stem) cells in vitro and corresponding patient-derived pancreatic cancer tissue xenografts in vivo. Intriguingly, we found that in vitro treatment with the antimalarial agent chloroquine significantly decreased CSCs, translating into diminished in vivo tumorigenicity and invasiveness in a large panel of pancreatic cancers. In vivo treatment in combination with gemcitabine was capable of more effectively eliminating established tumors and improved overall survival. The inhibitory effect of chloroquine was not related to inhibition of autophagy, but was due to inhibition of CXCL12/CXCR4 signaling, resulting in reduced phosphorylation of ERK and STAT3. Furthermore, chloroquine showed potent inhibition of hedgehog signaling by decreasing the production of Smoothened, translating into a significant reduction in sonic hedgehog-induced chemotaxis and downregulation of downstream targets in CSCs and the surrounding stroma. Our study demonstrates that via to date unreported effects, chloroquine is an effective adjuvant therapy to chemotherapy, offering more efficient tumor elimination and improved cure rates. Chloroquine should be further explored in the clinical setting as its success may help to more rapidly improve the poor prognosis of patients with pancreatic cancer.

Shaking the family tree: identification of novel and biologically active alternatively spliced isoforms across the KLF family of transcription factors.

Alternative splicing represents a unique post-transcriptional mechanism that increases the complexity of the eukaryotic proteome-generating protein isoforms whose functions can be novel, diverse, and/or even antagonistic when compared to its full-length transcript. The KLF family of genes consists of ≥17 members, which are involved in the regulation of numerous critical cellular processes, including differentiation, cell proliferation, growth-related signal transduction, angiogenesis, and apoptosis. Using a strategy based on RT-PCR, selective cloning, and promoter-based assays of cancer-relevant genes, we identify and characterize the existence of multiple biologically active KLF splice forms across the entire family of proteins. We demonstrate biological function for a number of these isoforms. Furthermore, we highlight a possible functional interaction between full-length KLF4 and one of its splice variants in up-regulating cellular proliferation. Taken together, this report identifies for the first time a more complete view of the genomic and proteomic breadth and complexity of the KLF transcription factor family, revealing the existence of highly expressed and biologically active isoforms previously uncharacterized. In essence, knowing that these KLF isoforms exist provides the first step toward understanding the roles of these genes in human health and disease.

Primate genome gain and loss: a bone dysplasia, muscular dystrophy, and bone cancer syndrome resulting from mutated retroviral-derived MTAP transcripts.

Diaphyseal medullary stenosis with malignant fibrous histiocytoma (DMS-MFH) is an autosomal-dominant syndrome characterized by bone dysplasia, myopathy, and bone cancer. We previously mapped the DMS-MFH tumor-suppressing-gene locus to chromosomal region 9p21-22 but failed to identify mutations in known genes in this region. We now demonstrate that DMS-MFH results from mutations in the most proximal of three previously uncharacterized terminal exons of the gene encoding methylthioadenosine phosphorylase, MTAP. Intriguingly, two of these MTAP exons arose from early and independent retroviral-integration events in primate genomes at least 40 million years ago, and since then, their genomic integration has gained a functional role. MTAP is a ubiquitously expressed homotrimeric-subunit enzyme critical to polyamine metabolism and adenine and methionine salvage pathways and was believed to be encoded as a single transcript from the eight previously described exons. Six distinct retroviral-sequence-containing MTAP isoforms, each of which can physically interact with archetype MTAP, have been identified. The disease-causing mutations occur within one of these retroviral-derived exons and result in exon skipping and dysregulated alternative splicing of all MTAP isoforms. Our results identify a gene involved in the development of bone sarcoma, provide evidence of the primate-specific evolution of certain parts of an existing gene, and demonstrate that mutations in parts of this gene can result in human disease despite its relatively recent origin.

Adsorption and detection of sport doping drugs on metallic plasmonic nanoparticles of different morphology.

A comparative study of different plasmonic nanoparticles with different morphologies (nanospheres and triangular nanoprisms) and metals (Ag and Au) was done in this work and applied to the ultrasensitive detection of aminoglutethimide (AGI) drug by surface enhanced Raman spectroscopy (SERS) and plasmon resonance. AGI is an aromatase inhibitor used as an antitumoral drug with remarkable pharmacological interest and also in illegal sport doping. The application of very sensitive spectroscopic techniques based on the localization of an electromagnetic field on plasmonic nanoparticles confirms the previous study of the adsorption of drugs onto a metal surface due to the near field character of these techniques. The adsorption of AGI on the above substrates was investigated at different pH values and surface coverages, and the results were analyzed on the basis of AGI/metal affinity, considering the interaction mechanism, the existence of two binding sites in AGI, and the influence of the interface on the adsorption in terms of surface charge due to the presence of other ions linked to the surface. Finally, a comparative quantitative detection of AGI was performed on both spherical and triangular nanoprism nanoparticles, and a limit of detection lower than those reported so far was deduced on the latter nanoparticles.

Nodal/Activin signaling drives self-renewal and tumorigenicity of pancreatic cancer stem cells and provides a target for combined drug therapy.

Nodal and Activin belong to the TGF-ß superfamily and are important regulators of embryonic stem cell fate. Here we investigated whether Nodal and Activin regulate self-renewal of pancreatic cancer stem cells. Nodal and Activin were hardly detectable in more differentiated pancreatic cancer cells, while cancer stem cells and stroma-derived pancreatic stellate cells markedly overexpressed Nodal and Activin, but not TGF-ß. Knockdown or pharmacological inhibition of the Nodal/Activin receptor Alk4/7 in cancer stem cells virtually abrogated their self-renewal capacity and in vivo tumorigenicity, and reversed the resistance of orthotopically engrafted cancer stem cells to gemcitabine. However, engrafted primary human pancreatic cancer tissue with a substantial stroma showed no response due to limited drug delivery. The addition of a stroma-targeting hedgehog pathway inhibitor enhanced delivery of the Nodal/Activin inhibitor and translated into long-term, progression-free survival. Therefore, inhibition of the Alk4/7 pathway, if combined with hedgehog pathway inhibition and gemcitabine, provides a therapeutic strategy for targeting cancer stem cells.

Pancreatic cancer stem cells: new insights and perspectives.

Since the identification of self-renewing cells in the hematopoietic system several decades ago, stem cells have changed the way we study biology and medicine. Solid tumors contain a distinct subpopulation of cells that have stem cell characteristics and are exclusively responsible for tumorigenicity. This discovery has led to the development of the stem cell concept of cancer, which proposes that a subpopulation of self-renewing tumor cells, also termed cancer stem cells, is responsible for tumorigenesis and metastasis. This contrasts with the stochastic model of tumor development, which holds that all tumor cells are capable of tumor initiation. Different subpopulations of cancer stem cells have been identified in pancreatic ductal adenocarcinoma, based on the use of combinations of surface markers that allow their isolation, propagation, and further characterization. Importantly, cancer stem cells are not only capable of self-renewal and differentiation, but may also confer virulence via immune system evasion and multidrug resistance, and potentially via vasculogenic mimicry and transition to migratory and metastasizing derivatives. Therapeutic targeting of this subset of cells and the pathways defining their virulence holds great promise for the development of more effective strategies for the amelioration and eradication of this most lethal form of cancer.

Manejo clínico de la caries profunda / Clinical management of deep caries lesion

La lesión cariosa profunda por la posibilidad de afectación pulpar, es un cuadro clínico de especial significación y permanente vigencia. Su tratamiento requiere de protocolos bien establecidos, de manera que la técnica empleada pueda ser conservadora y proporcione una amplia cobertura. Es fundamental el conocimiento de la etiopatogenia de los correctos diagnósticos de la salud pulpar, de las propiedades de bases y protectores, así como también del correcto sellado marginal de la restauración coronaria. El objetivo será siempre mantener de manera conservadora la salud pulpar, dejando a la pieza apta para su restauración en forma, función y estética. Este artículo recoge el trabajo de una comisión que sistemizó los protocolos clínicos para la Protección Pulpar Indirecta (PPI) y para el Tratamiento Pulpar Indirecto (TPI), con eliminación de caries en forma diferida. Los mismos se utilizan actualmente en la Clínica Integrada de Adultos III, Facultad de Odontología, Universidad de la República (Uruguay). Se considera que el Hidróxido de Calcio (Ca(OH)2) sigue manteniendo su vigencia, siendo condición necesaria de su uso una pulpa saludable y requerimientos de reacción defensiva por depósito de tejido mineralizado.

Self-assembly of alpha,omega-aliphatic diamines on Ag nanoparticles as an effective localized surface plasmon nanosensor based in interparticle hot spots.

The adsorption and self-assembly of alpha,omega-aliphatic diamines on silver nanoparticles is studied in this work by surface-enhanced Raman scattering (SERS) spectroscopy and plasmon resonance. These bifunctional diamines can act as linkers of metal nanoparticles (NPs) inducing the formation of hot spots (HS), i.e. interparticle junctions or gaps between metal NPs, which are points where a huge intensification of the electromagnetic field occurs. In addition, the dicationic nature of these diamines leads to the formation of cavities just at the induced hot spots which can be applied to molecular recognition of analytes. The influence of the surface coverage and the aliphatic chain length in diamines on their self-assembly was tested by the vibrational spectra and correlated to the different plasmon resonances of the dimers detected in the extinction spectra. These factors can be used for tuning the plasmon resonance of dimers formed by two metal nanoparticles where interparticle hot spots are formed. Finally, the analytical potential of these functionalized Ag nanoparticles is demonstrated for the trace detection of the pesticide aldrin.

Obturación de conductos radiculares por medio de la inyección de gutapercha termoplastizada (70 grados C): un estudio con microscopía electrónica de barrido / Root canal obturation by thermoplasticized gutta-percha injection (70 degree C): an electron scanning microcopy study

Cuarenta incisivos centrales y caninos superiores humanos fueron instrumentados y posteriormente obturados con gutapercha termoplastizada a 70 grados C, o mediante la condensación lateral de conos de gutapercha. En ambos casos, las obturaciones fueron radiográficamente controladas, en sentido vestíbulo palatino y mesiodistal. Luego de que los dientes fueran fracturados longitudinalmente, se analizó la adaptación de la gutapercha a la pared del conducto radicular como así también la frecuencia con que se producían sobreobturaciones, por medio del microscopio electrónico de barrido. A pesar de que la morfología de los conductos radiculares fue adecuadamente reproducida por ambas técnicas, la inyección de gutapercha termoplastizada parecería ser superior en su habilidad para replicar las irregularidades de las paredes dentinarias y para distribuirse a lo largo del conducto radicular en una masa más homogénea. Sin embargo, hubo en estos casos una mayor tendencia a la sobreobturación, siendo las diferencias entre ambos grupos, estadísticamente significativas (p < 0,05)

Obturación de conductos radiculares por medio de la inyección de gutapercha termoplastizada (70 grados C): un estudio con microscopía electrónica de barrido / Root canal obturation by thermoplasticized gutta-percha injection (70 degree C): an electron scanning microcopy study

Cuarenta incisivos centrales y caninos superiores humanos fueron instrumentados y posteriormente obturados con gutapercha termoplastizada a 70 grados C, o mediante la condensación lateral de conos de gutapercha. En ambos casos, las obturaciones fueron radiográficamente controladas, en sentido vestíbulo palatino y mesiodistal. Luego de que los dientes fueran fracturados longitudinalmente, se analizó la adaptación de la gutapercha a la pared del conducto radicular como así también la frecuencia con que se producían sobreobturaciones, por medio del microscopio electrónico de barrido. A pesar de que la morfología de los conductos radiculares fue adecuadamente reproducida por ambas técnicas, la inyección de gutapercha termoplastizada parecería ser superior en su habilidad para replicar las irregularidades de las paredes dentinarias y para distribuirse a lo largo del conducto radicular en una masa más homogénea. Sin embargo, hubo en estos casos una mayor tendencia a la sobreobturación, siendo las diferencias entre ambos grupos, estadísticamente significativas (p < 0,05) (AU)