A role for human Dicer in pre-RISC loading of siRNAs

RNA interference is a powerful mechanism for sequence-specific inhibition of gene expression. It is widely known that small interfering RNAs (siRNAs) targeting the same region of a target-messenger RNA can have widely different efficacies. In efforts to better understand the siRNA features that influence knockdown efficiency, we analyzed siRNA interactions with a high-molecular weight complex in whole cell extracts prepared from two different cell lines. Using biochemical tools to study the nature of the complex, our results demonstrate that the primary siRNA-binding protein in the whole cell extracts is Dicer. We find that Dicer is capable of discriminating highly functional versus poorly functional siRNAs by recognizing the presence of 2-nt 3′ overhangs and the thermodynamic properties of 2–4 bp on both ends of effective siRNAs. Our results suggest a role for Dicer in pre-selection of effective siRNAs for handoff to Ago2. This initial selection is reflective of the overall silencing potential of an siRNA

Gene expression profile changes after short-activating RNA-mediated induction of endogenous pluripotency factors in human mesenchymal stem cells

It is now recognized that small noncoding RNA sequences have the ability to mediate transcriptional activation of specific target genes in human cells. Using bioinformatics analysis and functional screening, we screened short-activating RNA (saRNA) oligonucleotides designed to target the promoter regions of the pluripotency reprogramming factors, Kruppel-like factor 4 (KLF4) and c-MYC. We identified KLF4 and c-MYC promoter-targeted saRNA sequences that consistently induced increases in their respective levels of nascent mRNA and protein expression in a time- and dose-dependent manner, as compared with scrambled sequence control oligonucleotides. The functional consequences of saRNA-induced activation of each targeted reprogramming factor were then characterized by comprehensively profiling changes in gene expression by microarray analysis, which revealed significant increases in mRNA levels of their respective downstream pathway genes. Notably, the microarray profile after saRNA-mediated induction of endogenous KLF4 and c-MYC showed similar gene expression patterns for stem cell- and cell cycle-related genes as compared with lentiviral vector-mediated overexpression of exogenous KLF4 and c-MYC transgenes, while divergent gene expression patterns common to viral vector-mediated transgene delivery were also noted. The use of promoter-targeted saRNAs for the activation of pluripotency reprogramming factors could have broad implications for stem cell research

Studies on W.B. Yeats

Dans ce recueil convergent différents regards sur la poésie de W.B. Yeats. Ces pages le situent par rapport à d’autres poètes comme MacNeice. Elles nous promènent aussi des premiers volumes, où l’espace de l’écriture devient l’écriture de l’espace, à Responsabilities, volume qui témoigne d’une intensité qu’Ezra Pound qualifie de « robustesse nouvelle », puis à travers les thèmes sexuels, politiques et esthétiques de Michael Robartes and the Dancer. Nous abordons ensuite les grands poèmes de la maturité avec The Tower. Cet ouvrage envisage également des sujets généraux, comme l’importance de la tradition pour Yeats, sa conception de l’au-delà avec la dette envers l’Inde en particulier, son attitude face à la dégénérescence, sa vision de l’Apocalypse avec le symbole de la spirale. D’autres études se concentrent sur certains grands poèmes tels que « The Circus Animais Desertion », qui tisse ensemble et la vie et l’art, ou « Lapis Lazuli » et la notion de « joie tragique ».In this book, different perspectives on W. B. Yeats' poetry converge. These pages place him in relation to other poets such as MacNeice. They also take us from the first volumes, where the space of writing becomes the writing of space, to Responsabilities, a volume that reflects an intensity that Ezra Pound calls "new robustness", and then through the sexual, political and aesthetic themes of Michael Robartes and the Dancer. We then discuss the great poems of maturity with The Tower. This book also considers general topics, such as the importance of tradition for Yeats, his conception of the afterlife with the debt to India in particular, his attitude towards degeneration, his vision of the Apocalypse with the symbol of the spiral. Other studies focus on some major poems such as "The Circus Animais Desertion", which weaves together life and art, or "Lapis Lazuli" and the notion of "tragic joy"

Multi-center phase II trial of bortezomib and rituximab maintenance combination therapy in patients with mantle cell lymphoma after consolidative autologous stem cell transplantation

Abstract Background Mantle cell lymphoma (MCL) is an aggressive and incurable lymphoma. Standard of care for younger patients with MCL is induction chemotherapy followed by autologous stem cell transplantation (auto-HCT). Rituximab maintenance after auto-HCT has been shown to improve progression-free survival (PFS) and overall survival (OS) in MCL. Bortezomib maintenance therapy has also been shown to be tolerable and feasible in this setting. However, the combination of bortezomib and rituximab as maintenance therapy post-auto-HCT has not been studied. Methods We conducted a multicenter, phase II trial of bortezomib given in combination with rituximab as maintenance in MCL patients after consolidative auto-HCT. Enrolled patients (n = 23) received bortezomib 1.3 mg/m2 subcutaneously weekly for 4 weeks every 3 months (up to 24 months) and rituximab 375 mg/m2 intravenously weekly for 4 weeks every 6 months (up to 24 months) for a total duration of 2 years. The primary study endpoint was disease-free survival (DFS). Results With a median follow-up of 35.9 months, the 2-year DFS probability was 90.2% (95% CI 66–97), and 2-year OS was 94.7% (95% CI 68–99). The most frequent grade 3/4 toxic events were neutropenia (in 74% of patients) and lymphopenia (in 35%). The incidence of peripheral neuropathy was 48% for grade 1, 9% for grade 2, and 0% for grade 3/4. We also examined the role of quantitative cyclin D1 (CCND1) mRNA in monitoring minimal residual disease. Conclusion Combined bortezomib and rituximab as maintenance therapy in MCL patients following auto-HCT is an active and well-tolerated regimen. Trial registration ClinicalTrials.gov NCT01267812, registered Dec 29, 2010

NG2 antigen is involved in leukemia invasiveness and central nervous system infiltration in MLL-rearranged infant B-ALL

Mixed-lineage leukemia (MLL)-rearranged (MLLr) infant B-cell acute lymphoblastic leukemia (iMLLr-B-ALL) has a dismal prognosis and is associated with a pro-B/mixed phenotype, therapy refractoriness and frequent central nervous system (CNS) disease/relapse. Neuron-glial antigen 2 (NG2) is specifically expressed in MLLr leukemias and is used in leukemia immunophenotyping because of its predictive value for MLLr acute leukemias. NG2 is involved in melanoma metastasis and brain development; however, its role in MLL-mediated leukemogenesis remains elusive. Here we evaluated whether NG2 distinguishes leukemia-initiating/propagating cells (L-ICs) and/or CNS-infiltrating cells (CNS-ICs) in iMLLr-B-ALL. Clinical data from the Interfant cohort of iMLLr-B-ALL demonstrated that high NG2 expression associates with lower event-free survival, higher number of circulating blasts and more frequent CNS disease/relapse. Serial xenotransplantation of primary MLL-AF4+ leukemias indicated that NG2 is a malleable marker that does not enrich for L-IC or CNS-IC in iMLLr-B-All. However, NG2 expression was highly upregulated in blasts infiltrating extramedullar hematopoietic sites and CNS, and specific blockage of NG2 resulted in almost complete loss of engraftment. Indeed, gene expression profiling of primary blasts and primografts revealed a migratory signature of NG2+ blasts. This study provides new insights on the biology of NG2 in iMLLr-B-ALL and suggests NG2 as a potential therapeutic target to reduce the risk of CNS disease/relapse and to provide safer CNS-directed therapies for iMLLr-B-ALL.This work was supported by the European Research Council (CoG-2014-646903) and the Spanish Ministry of Economy-Competitiveness (SAF-SAF2013-43065) to PM, the Asociación Española Contra el Cáncer to CB and the ISCIII/FEDER (PI14/01191-PI13/00168) to CB and JCRM. PM acknowledges the financial support from the Obra Social La Caixa-Fundaciò Josep Carreras, the Inocente-Inocente Foundation and Generalitat de Catalunya. CP and DRM were funded by PFIS scholarships from the ISCIII. VA has financial support from L’Oreal-UNESCO. PM is investigator of the Spanish Cell Therapy cooperative network (TERCEL). We thank Antonio Agraz/Ignacio Varela (IBBTEC, Santander) for assisting in microarray analysis. We also thank Dr Patricia Pérez-Galán and Gael Roue (IDIBAPS, Barcelona, Spain) for helpful discussions on NG2 blocking experiments