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Embryonic stem cells (ESCs) fluctuate among different levels of pluripotency defined as metastates. Sporadically, metastable cellular populations convert to a highly pluripotent metastate that resembles the preimplantation two-cell embryos stage (defined as 2C stage) in terms of transcriptome, DNA methylation, and chromatin structure. Recently, we found that the retinoic acid (RA) signaling leads to a robust increase of cells specifically expressing 2C genes, such as members of the Prame family. Here, we show that Gm12794c, one of the most highly upregulated Prame members, and previously identified as a key player for the maintenance of pluripotency, has a functional role in conferring ESCs resistance to RA signaling. In particular, RA-dependent expression of Gm12794c induces a ground state-like metastate, as evaluated by activation of 2C-specific genes, global DNA hypomethylation and rearrangement of chromatin similar to that observed in naive totipotent preimplantation epiblast cells and 2C-like cells. Mechanistically, we demonstrated that Gm12794c inhibits Cdkn1A gene expression through the polycomb repressive complex 2 (PRC2) histone methyltransferase activity. Collectively, our data highlight a molecular mechanism employed by ESCs to counteract retinoic acid differentiation stimuli and contribute to shed light on the molecular mechanisms at grounds of ESCs naive pluripotency-state maintenance.

// Antonella Caivano 1 , Francesco La Rocca 1 , Ilaria Laurenzana 1 , Tiziana Annese 2 , Roberto Tamma 2 , Ubaldo Famigliari 3 , Vittorio Simeon 1 , Stefania Trino 1 , Luciana De Luca 1 , Oreste Villani 4 , Simona Berardi 5 , Antonio Basile 5 , Angelo Vacca 5 , Giuseppe Saglio 6 , Luigi Del Vecchio 7, 8 , Pellegrino Musto 9 , Daniela Cilloni 6 1 Laboratory of Pre-clinical and Translational Research, Scientific Institute of Research and Cure (IRCCS), Referral Cancer Center of Basilicata (CROB), Rionero in Vulture, Italy 2 Department of Human Anatomy, Histology and Embryology, University of Bari Medical School, Bari, Italy 3 Division of Pathology, Department of Oncology, St Luigi Hospital, Turin, Italy 4 Department of Onco-Hematology, IRCCS-CROB, Rionero in Vulture, Italy 5 Department of Biomedical Sciences and Human Oncology, University of Bari Medical School, Bari, Italy 6 Department of Clinical and Biological Sciences, University of Turin, Orbassano, Italy 7 CEINGE-Biotecnologie Avanzate s.c.a r.l and Medical Biotechnologies, Federico II University, Naples, Italy 8 Department of Molecular Medicine and Medical Biotechnologies, Federico II University, Naples, Italy 9 Scientific Direction, IRCCS-CROB, Rionero in Vulture, Italy Correspondence to: Antonella Caivano, email: caivanoa@libero.it Keywords: angiogenesis, bone marrow endothelial cells, receptor tyrosine kinase, EphA3, multiple myeloma Received: September 02, 2016 Accepted: March 01, 2017 Published: March 10, 2017 ABSTRACT This study investigates the role of ephrin receptor A3 (EphA3) in the angiogenesis of Multiple Myeloma (MM) and the effects of a selective target of EphA3 by a specific monoclonal antibody on primary bone marrow endothelial cells (ECs) of MM patients. EphA3 mRNA and protein were evaluated in ECs of MM patients (MMECs), in ECs of patients with monoclonal gammopathies of undetermined significance (MGECs) and in ECs of healthy subjects (control ECs). The effects of EphA3 targeting by mRNA silencing (siRNA) or by the anti EphA3 antibody on the angiogenesis were evaluated. We found that EphA3 is highly expressed in MMECs compared to the other EC types. Loss of function of EphA3 by siRNA significantly inhibited the ability of MMECs to adhere to fibronectin, to migrate and to form tube like structures in vitro , without affecting cell proliferation or viability. In addition, gene expression profiling showed that knockdown of EphA3 down modulated some molecules that regulate adhesion, migration and invasion processes. Interestingly, EphA3 targeting by an anti EphA3 antibody reduced all the MMEC angiogenesis-related functions in vitro . In conclusion, our findings suggest that EphA3 plays an important role in MM angiogenesis.

Background Allogeneic hematopoietic stem cell transplantation (AHSCT) is a curative therapeutic approach for different hematological malignancies (HMs), and epigenetic modifications, including DNA methylation, play a role in the reconstitution of the hematopoietic system after AHSCT. This study aimed to explore global DNA methylation dynamic of bone marrow (BM) hematopoietic stem and progenitor cells (HSPCs) from donors and their respective recipients affected by acute myeloid leukemia (AML), acute lymphoid leukemia (ALL) and Hodgkin lymphoma (HL) during the first year after transplant. Methods We measured DNA methylation profile by Illumina HumanMethylationEPIC in BM HSPC of 10 donors (t0) and their matched recipients at different time points after AHSCT, at day + 30 (t1), + 60 (t2), + 120 (t3), + 180 (t4), and + 365 (t5). Differential methylation analysis was performed by using R software and CRAN/Bioconductor packages. Gene set enrichment analysis was carried out on promoter area of significantly differentially methylated genes by clusterProfiler package and the mSigDB genes sets. Results Results show significant differences in the global methylation profile between HL and acute leukemias, and between patients with mixed and complete chimerism, with a strong methylation change, with prevailing hyper-methylation, occurring 30 days after AHSCT. Functional analysis of promoter methylation changes identified genes involved in hematopoietic cell activation, differentiation, shaping, and movement. This could be a consequence of donor cell “adaptation” in recipient BM niche. Interestingly, this epigenetic remodeling was reversible, since methylation returns similar to that of donor HSPCs after 1 year. Only for a pool of genes, mainly involved in dynamic shaping and trafficking, the DNA methylation changes acquired after 30 days were maintained for up to 1 year post-transplant. Finally, preliminary data suggest that the methylation profile could be used as predictor of relapse in ALL. Conclusions Overall, these data provide insights into the DNA methylation changes of HSPCs after transplantation and a new framework to investigate epigenetics of AHSCT and its outcomes. Electronic supplementary material The online version of this article (10.1186/s13287-019-1245-6) contains supplementary material, which is available to authorized users.

Background: Thecross talk between neoplastic cells and microenvironment is mediated by direct cell-to-cell contacts, secretion of soluble factors and release of extracellular vesicles (EVs). EVs deriving from tumor cells in chronic lymphocytic leukemia (CLL) may affect the surrounding microenvironment, playing a key role on survival of neoplastic clone. Of note, EVs are increased in CLL patients compared to normal subjects. In this study, we performed a comprehensive characterization of serum EVs from previously untreated CLL patients, investigating, in particular, phenotype and absolute number, in order to test their possible prognostic significance. Patients and methods: Serum samples of 131 newly diagnosed CLL and from 28 healthy subjects were analyzed. One milliliter of serum was processed with serial ultracentrifugations. Each sample of EV-enriched pellet, from patients and controls, was freshly analyzed by FACS Calibur (Becton Dickinson BD) cytometer using Cell Quest software (BD). The system was calibrated using standard microbeads with a diameter of 0.3-0.9-3 μm to define the size limit for microvesicles (MV), a subtype of EVs. To determine the number of MV/μL serum, TruCOUNT beads (BD) were added immediately prior to analysis by flow cytometry. MV morphology was characterized by transmission electron microscope (TEM). MV were then labeled with fluorochrome-conjugated monoclonal antibodies (anti-CD19, CD3, CD94, CD20, CD2, CD56, CD52, CD37) and their specific isotypic controls. Finally, MV were correlated with the main clinical and biological disease's characteristics, including clinical outcome. Results: Flow cytometric analysis of MVs showed a size within 1mm, based on forward and side scatter evaluation and the use of standard beads. The analysis was carried out on MV population isolated by the gating strategy. MV were also visualized by TEM, showing a spheroid morphology. We found a significantly higher mean number of MV in CLL patients with respect to healthy subjects (p Conclusions: Our study indicates that: (i) MV number is higher in CLL patients as compared to normal controls; (ii) CD19 and CD37 are the most represented B-cell antigens on CLL derived MV; (iii) total MV levels are associated with high tumor burden; (iv) total MV levels predict for TTT in Rai 0 patients, as well as for TTT and OS in all stage patients. These observations suggest that MV may represent a new biomarker for CLL. Disclosures D'Arena: Janssen-Cilag: Honoraria. Musto:Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Purpose: Multiple myeloma (MM) is a hematologic malignancy characterized by a clonal expansion of plasma cells (PCs) in the bone marrow (BM). Since MM has so far remained incurable, further insights into its pathogenesis and the concomitant identification of new therapeutic targets are urgently needed. The tyrosine kinase receptor EphA3 is known to be involved in various cellular processes including cell viability, cell movement and cell-cell interactions. Recently, EphA3 has emerged as a potential therapeutic target in several hematologic and solid tumors. Here, we aimed to uncover the role of EphA3 in MM. Methods: EphA3 mRNA and protein expression in primary MM bone marrow plasma cells (BMPCs), in MM-derived cell lines and in healthy controls (HCs) was assessed using qRT-PCR, Western blotting and flow cytometry. The effects of siRNA-mediated EphA3 silencing and anti EphA3 antibody (EphA3mAb) treatment on MM PC trafficking and viability were evaluated using in vitro assays. The effects of EphA3mAb treatment were also assessed in two MM-derived mouse xenograft models. Results: We found that EphA3 was overexpressed in primary MM BMPCs and MM-derived cell lines compared to HCs. We also found that siRNA-mediated EphA3 silencing and EphA3mAb treatment significantly inhibited the ability of MM PCs to adhere to fibronectin and stromal cells and to invade in vitro, without affecting cell proliferation and viability. Gene expression profiling showed that EphA3 silencing resulted in expression modulation of several molecules that regulate adhesion, migration and invasion processes. Importantly, we found that EphA3mAb treatment significantly inhibited in vivo tumor growth and angiogenesis in two MM-derived mouse xenograft models. Conclusions: Our findings suggest that EphA3 plays an important role in the pathogenesis of MM and provide support for the notion that its targeting may represent a novel therapeutic opportunity for MM.

Lin28A is a highly conserved RNA-binding protein that concurs to control the balance between stemness and differentiation in several tissue lineages. Here, we report the role of miR-128a/Lin28A axis in blocking cell differentiation in acute myeloid leukemia (AML), a genetically heterogeneous disease characterized by abnormally controlled proliferation of myeloid progenitor cells accompanied by partial or total inability to undergo terminal differentiation. First, we found Lin28A underexpressed in blast cells from AML patients and AML cell lines as compared with CD34+ normal precursors. In vitro transfection of Lin28A in NPM1-mutated OCI-AML3 cell line significantly triggered cell-cycle arrest and myeloid differentiation, with increased expression of macrophage associate genes (EGR2, ZFP36 and ANXA1). Furthermore, miR-128a, a negative regulator of Lin28A, was found overexpressed in AML cells compared with normal precursors, especially in acute promyelocytic leukemia (APL) and in ‘AML with maturation’ (according to 2016 WHO classification of myeloid neoplasms and acute leukemia). Its forced overexpression by lentiviral infection in OCI-AML3 downregulated Lin28A with ensuing repression of macrophage-oriented differentiation. Finally, knockdown of miR-128a in OCI-AML3 and in APL/AML leukemic cells (by transfection and lentiviral infection, respectively) induced myeloid cell differentiation and increased expression of Lin28A, EGR2, ZFP36 and ANXA1, reverting myeloid differentiation blockage. In conclusion, our findings revealed a new mechanism for AML differentiation blockage, suggesting new strategies for AML therapy based upon miR-128a inhibition.

Gastric cancer (GC) remains one of the major causes of cancer-related mortality worldwide. As for other types of cancers, several limitations to the success of current therapeutic GC treatments may be due to cancer drug resistance that leads to tumor recurrence and metastasis. Increasing evidence suggests that cancer stem cells (CSCs) are among the major causative factors of cancer treatment failure. The research of molecular CSC mechanisms and the regulation of their properties have been intensively studied. To date, molecular gastric cancer stem cell (GCSC) characterization remains largely incomplete. Among the GCSC-targeting approaches to overcome tumor progression, recent studies have focused their attention on microRNA (miRNA). The miRNAs are short non-coding RNAs which play an important role in the regulation of numerous cellular processes through the modulation of their target gene expression. In this review, we summarize and discuss recent findings on the role of miRNAs in GCSC regulation. In addition, we perform a meta-analysis aimed to identify novel miRNAs involved in GCSC homeostasis.

Molecular targeted therapies are based upon drugs acting on tumors by interfering with specific targets involved in growth and spread of cancer. Many targeted therapies were approved by Food and Drug Administration as standard treatment, others were introduced into preclinical or clinical studies on hematological malignancies (HMs). The development of drug-resistance in some HMs and the lack of effective treatments in other ones emphasized the need for searching new molecular targets and therapeutic agents. The aim of this study was to evaluate the effects of 4c pyrazolo[3,4-d]pyrimidine compound, a Src inhibitor, on lymphoid and myeloid neoplasms. Here, we demonstrated its ability to reduce cell viability, induce apoptosis and cell cycle arrest in lymphoid cell lines such as Jurkat, SKMM1, Derl-2/7, and myeloid cell lines, such as Jurl-MK1. Moreover, we reported a high expression of a Src kinase, Fyn, in these cell lines compared to healthy subjects. This study was a starting point to investigate 4c pyrazolo[3,4-d]pyrimidine compound as a drug for HMs and Src kinases as its potential molecular targets.

The use of extracellular vesicles (EVs) from body fluids as “liquid biopsies” is emerging as a promising approach for the diagnosis, prognosis and therapeutic monitoring of cancer patients. MicroRNA-155 (miR155), a non-coding transcript of the B-cell integration cluster (BIC) gene, has been reported to play a critical role in the pathogenesis of several types of hematologic malignancies (HMs) in which high miR155 levels have been found. At yet, however, the EV miR155 level and its putative clinical relevance in sera of HM patients have not been reported. EVs from sera of representative patients with eight different HMs and healthy subjects (controls) were isolated using differential centrifugation. The identity and quality of the EVs were verified by atomic force and transmission electron microscopy. The EV miR155 levels were measured by quantitative RT-PCR. The sensitivity, specificity and area under the curve (AUC) of differences in EV miR155 levels were determined using ROC curve analyses. We found that the EV miR155 levels were significantly higher in chronic lymphocytic leukemia (CLL), acute myeloid leukemia (AML) and Waldenstrom’s macroglobulinemia (WM) cases compared to controls. Conversely, we found that the EV miR155 levels were significantly lower in myelodysplastic syndrome (MDS) and multiple myeloma (MM) cases. No differences were found in follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL) or Hodgkin’s Lymphoma (HL) cases compared to controls. EV miR155 ROC curve analyses revealed significantly different patterns in CLL and AML cases compared to controls, and in AML cases compared to MDS cases (p = 0.004, p = 0.01 and p = 0.04, respectively). In addition, we found that high EV miR155 levels correlated with high white blood cell counts in AML patients. Our data indicate that EV miR155 may serve as an attractive new, non-invasive diagnostic biomarker in human hematologic malignancies.