Hematopathology Unit


Hematopathology Unit

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Colomer D.,Hematopathology Unit | Nakanishi M.,Japan National Institute of Advanced Industrial Science and Technology | Menendez P.,Catalan Institution for Research and Advanced Studies
Stem Cells | Year: 2016

Although B cells have been shown to be refractory to reprogramming into pluripotency, induced pluripotent stem cells (iPSCs) have been very recently generated, at very low efficiency, from human cord blood (CB)- and peripheral blood (PB)-derived CD19+CD20+B cells using nonintegrative tetracistronic OSKM-expressing Sendai Virus (SeV). Here, we addressed whether cell ontogeny and hierarchy influence the reprogramming efficiency of the B-cell compartment. We demonstrate that human fetal liver (FL)-derived CD19+B cells are 110-fold easier to reprogram into iPSCs than those from CB/PB. Similarly, FL-derived CD34+CD19+B progenitors are reprogrammed much easier than mature B cells (0.46% vs. 0.11%). All FL B-cell iPSCs carry complete VDJH rearrangements while 55% and 45% of the FL B-progenitor iPSCs carry incomplete and complete VDJH rearrangements, respectively, reflecting the reprogramming of developmentally different B progenitors (pro-B vs. pre-B) within a continuous differentiation process. Finally, our data suggest that successful B-cell reprogramming relies on active cell proliferation, and it is MYC-dependent as identical nonintegrative polycistronic SeV lacking MYC (OSKL or OSKLN) fail to reprogram B cells. The ability to efficiently reprogram human fetal primary B cells and B precursors offers an unprecedented opportunity for studying developmental B-lymphopoiesis and modeling B-cell malignances. Stem Cells 2016 Human B-cell progenitors are reprogrammed into iPSCs significantly easier than committed B-lymphocytes. Similarly, human fetal B-cells are reprogrammed into iPSCs at much higher efficiency than neonatal (cord blood) and adult (peripheral blood) B-cells, highlighting how cellular hierarchy and ontogeny impact reprogramming into pluripotency. Early ontogeny and immature phenotype are associated to higher proliferation rates, a key mechanism underlying reprogramming. © 2016 AlphaMed Press.

Palomero J.,Hematopathology Unit | Vegliante M.C.,Hematopathology Unit | Rodriguez M.L.,Hematopathology Unit | Eguileor A.,Hematopathology Unit | And 8 more authors.
Blood | Year: 2014

SOX11 is overexpressed in several solid tumors and in the vast majority of aggressive mantle cell lymphomas (MCLs). We have recently proven that SOX11 silencing reduces tumor growth in aMCLxenograft model, consistent with the indolent clinical course of the human SOX11-negative mantle cell lymphoma (MCL). However, the direct oncogenic mechanisms and downstream effector pathways implicated in SOX11-driven transformation remain poorly understood. Here, we observed that SOX11-positive xenograft and human primary MCL tumors overexpressed angiogenic gene signatures and had a higher microvascular density compared with their SOX11-negative counterparts. Conditioned media of SOX11-positive MCL cell lines induced in vitro endothelial cell proliferation, migration, tube formation, and activation of downstream angiogenic pathways.We identified PDGFA as a SOX11 direct target gene upregulated in MCL cells whose inhibition impaired SOX11-enhanced in vitro angiogenic effects on endothelial cells. In addition, platelet-derived growth factorA(PDGFA) was overexpressed inSOX11-positive but not in SOX11-negativeMCL. In vivo, imatinib impaired tumor angiogenesis and lymphoma growth in SOX11-positiveMCL xenograft tumors. Overall, our results demonstrate a prominent role for SOX11 as a driver of proangiogenic signals in MCL, and highlight the SOX11-PDGFA axis as a potential therapeutic target for the treatment of this aggressive disease. (Blood. 2014;124(14):2235-2247). © 2014 by The American Society of Hematology.

Matas-Cespedes A.,Experimental Therapeutics in Lymphoid Malignancies Group | Rodriguez V.,Experimental Therapeutics in Lymphoid Malignancies Group | Kalko S.G.,Bioinformatics Core Facility | Vidal-Crespo A.,Experimental Therapeutics in Lymphoid Malignancies Group | And 12 more authors.
Clinical Cancer Research | Year: 2014

Purpose: To uncover the signaling pathways underlying follicular lymphoma-follicular dendritic cells (FL-FDC) cross-talk and its validation as new targets for therapy. Experimental Design: FL primary cells and cell lines were cocultured in the presence or absence of FDC. After 24 and 48 hours, RNA was isolated from FL cells and subjected to gene expression profiling (CEP) and data meta-analysis using DAVID and GSEA softwares. Blockade of PI3K pathway by the pan-PI3K inhibitor BKM120 (buparlisib; Novartis Pharmaceutical Corporation) and the effect of PI3K inhibition on FL-FDC cross-talk were analyzed by means of ELISA, RT-PCR, human umbilical vein endothelial cell tube formation, adhesion and migration assays, Western blot, and in vivo studies in mouse FL xenografts. Results: GEP of FL-FDC cocultures yields a marked modulation of FL transcriptome by FDC. Pathway assignment by DAVID and GSEA software uncovered an overrepresentation of genes related to angiogenesis, cell adhesion, migration, and serum-response factors. We demonstrate that the addition of the pan-PI3K inhibitor BKM120 to the cocultures was able to downregulate the expression and secretion of proangiogenic factors derived from FL-FDC cocultures, reducing in vitro and in vivo angiogenesis. Moreover, BKM 120 efficiently counteracts FDC-mediated cell adhesion and impedes signaling and migration induced by the chemokine CXCL12. BKM120 inhibits both constitutive PI3K/AKT pathway and FDC- or CXCL12-induced PI3K/AKT pathway, hampers FDC survival signaling, and reduces cell proliferation of FL cells in vitro and in mouse xenografts. Conclusions: These data support the use of BKM 120 in FL therapy to counteract microenvironment-related survival signaling in FL cells. © 2014 American Association for Cancer Research.

Ferrer G.,University of Barcelona | Navarro A.,University of Barcelona | Hodgson K.,University of Barcelona | Aymerich M.,Hematopathology Unit | And 5 more authors.
Leukemia and Lymphoma | Year: 2013

Chronic lymphocytic leukemia (CLL) is frequently associated with autoimmune hemolytic anemia (AIHA). However, the mechanisms governing the association between CLL and AIHA are poorly understood. MicroRNAs (miRNAs) have been associated with different clinico-biological forms of CLL and are also known to play a substantial role in autoimmunity. However, there are no studies correlating miRNA expression with the likelihood that patients with CLL will develop AIHA. In this study, we found that malignant B-cells from patients with CLL subsequently developing AIHA present nine down-regulated (i.e. miR-19a, miR-20a, miR-29c, miR-146b-5p, miR-186, miR-223, miR-324-3p, miR-484 and miR-660) miRNAs. Interestingly, two of these miRNAs (i.e. miR-20a and miR-146b-5p) are involved in autoimmune phenomena, and one (i.e. miR-146b-5p) in both autoimmunity and CLL. Furthermore, we demonstrated that miR-146b-5p modulates CD80, a molecule associated with the B-T-cell synapse and in restoration of the antigen presenting cell capacity of CLL cells. © 2013 Informa UK, Ltd.

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