Imprinting fidelity in mouse iPSCs depends on sex of donor cell and medium formulation.

Reprogramming of somatic cells into induced Pluripotent Stem Cells (iPSCs) is a major leap towards personalised approaches to disease modelling and cell-replacement therapies. However, we still lack the ability to fully control the epigenetic status of iPSCs, which is a major hurdle for their downstream applications. Epigenetic fidelity can be tracked by genomic imprinting, a phenomenon dependent on DNA methylation, which is frequently perturbed in iPSCs by yet unknown reasons.

Analysis of T cell receptor clonotypes in tumor microenvironment identifies shared cancer-type-specific signatures.

Despite the conventional view that a truly random V(D)J recombination process should generate a highly diverse immune repertoire, emerging reports suggest that there is a certain bias toward the generation of shared/public immune receptor chains. These studies were performed in viral diseases where public T cell receptors (TCR) appear to confer better protective responses. Selective pressures generating common TCR clonotypes are currently not well understood, but it is believed that they confer a growth advantage.

Mutational synergy during leukemia induction remodels chromatin accessibility, histone modifications and three-dimensional DNA topology to alter gene expression.

Altered transcription is a cardinal feature of acute myeloid leukemia (AML); however, exactly how mutations synergize to remodel the epigenetic landscape and rewire three-dimensional DNA topology is unknown. Here, we apply an integrated genomic approach to a murine allelic series that models the two most common mutations in AML: Flt3-ITD and Npm1c. We then deconvolute the contribution of each mutation to alterations of the epigenetic landscape and genome organization, and infer how mutations synergize in the induction of AML.

Synergistic targeting of FLT3 mutations in AML via combined menin-MLL and FLT3 inhibition.

The interaction of menin (MEN1) and MLL (MLL1, KMT2A) is a dependency and provides a potential opportunity for treatment of NPM1-mutant (NPM1mut) and MLL-rearranged (MLL-r) leukemias. Concomitant activating driver mutations in the gene encoding the tyrosine kinase FLT3 occur in both leukemias and are particularly common in the NPM1mut subtype. In this study, transcriptional profiling after pharmacological inhibition of the menin-MLL complex revealed specific changes in gene expression, with downregulation of the MEIS1 transcription factor and its transcriptional target gene FLT3 being the most pronounced.

Vitamin D Receptor Controls Cell Stemness in Acute Myeloid Leukemia and in Normal Bone Marrow.

Vitamin D (VD) is a known differentiating agent, but the role of VD receptor (VDR) is still incompletely described in acute myeloid leukemia (AML), whose treatment is based mostly on antimitotic chemotherapy. Here, we present an unexpected role of VDR in normal hematopoiesis and in leukemogenesis. Limited VDR expression is associated with impaired myeloid progenitor differentiation and is a new prognostic factor in AML.

Genetic modification of primary human B cells to model high-grade lymphoma.

Sequencing studies of diffuse large B cell lymphoma (DLBCL) have identified hundreds of recurrently altered genes. However, it remains largely unknown whether and how these mutations may contribute to lymphomagenesis, either individually or in combination. Existing strategies to address this problem predominantly utilize cell lines, which are limited by their initial characteristics and subsequent adaptions to prolonged in vitro culture.

Molecular synergy underlies the co-occurrence patterns and phenotype of -mutant acute myeloid leukemia.

mutations define the commonest subgroup of acute myeloid leukemia (AML) and frequently co-occur with internal tandem duplications (ITD) or, less commonly, or mutations. Co-occurrence of mutant with carries a significantly worse prognosis than combinations. To understand the molecular basis of these observations, we compare the effects of the 2 combinations on hematopoiesis and leukemogenesis in knock-in mice.

Hemopoietic-specific Sf3b1-K700E knock-in mice display the splicing defect seen in human MDS but develop anemia without ring sideroblasts.

Heterozygous somatic mutations affecting the spliceosome gene SF3B1 drive age-related clonal hematopoiesis, myelodysplastic syndromes (MDS) and other neoplasms. To study their role in such disorders, we generated knock-in mice with hematopoietic-specific expression of Sf3b1-K700E, the commonest type of SF3B1 mutation in MDS. Sf3b1 animals had impaired erythropoiesis and progressive anemia without ringed sideroblasts, as well as reduced hematopoietic stem cell numbers and host-repopulating fitness.

A CRISPR Dropout Screen Identifies Genetic Vulnerabilities and Therapeutic Targets in Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is an aggressive cancer with a poor prognosis, for which mainstream treatments have not changed for decades. To identify additional therapeutic targets in AML, we optimize a genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) screening platform and use it to identify genetic vulnerabilities in AML cells. We identify 492 AML-specific cell-essential genes, including several established therapeutic targets such as DOT1L, BCL2, and MEN1, and many other genes including clinically actionable candidates.

Targeting Chromatin Regulators Inhibits Leukemogenic Gene Expression in NPM1 Mutant Leukemia.

Unlabelled: Homeobox (HOX) proteins and the receptor tyrosine kinase FLT3 are frequently highly expressed and mutated in acute myeloid leukemia (AML). Aberrant HOX expression is found in nearly all AMLs that harbor a mutation in the Nucleophosmin (NPM1) gene, and FLT3 is concomitantly mutated in approximately 60% of these cases. Little is known about how mutant NPM1 (NPM1) cells maintain aberrant gene expression.

Mouse models of NPM1-mutated acute myeloid leukemia: biological and clinical implications.

Acute myeloid leukemia (AML) carrying nucleophosmin (NPM1) mutations displays distinct biological and clinical features that led to its inclusion as a provisional disease entity in the 2008 World Health Organization (WHO) classification of myeloid neoplasms. Studies of the molecular mechanisms underlying the pathogenesis of NPM1-mutated AML have benefited greatly from several mouse models of this leukemia developed over the past few years. Immunocompromised mice xenografted with NPM1-mutated AML served as the first valuable tool for defining the biology of the disease in vivo.

ArrayExpress update--trends in database growth and links to data analysis tools.

The ArrayExpress Archive of Functional Genomics Data (http://www.ebi.ac.

Quercetin induced apoptosis in association with death receptors and fludarabine in cells isolated from chronic lymphocytic leukaemia patients.

Background: Quercetin is a flavonoid naturally present in food and beverages belonging to the large class of phytochemicals with potential anti-cancer properties. Here, we investigated the ability of quercetin to sensitise primary cells from chronic lymphocytic leukaemia (CLL) to death receptor (DR) agonists, recombinant TNF-related-apoptosis-inducing ligand (rTRAIL) and anti-CD95, and to fludarabine, a widely used chemotherapeutic drug against CLL.

Methods: Peripheral white blood cells were isolated from patients and incubated with medium containing 50 ng ml anti-CD95 agonist antibody; 10 ng ml recombinant TRAIL; 10-25 microM quercetin and 3.

Tbx1 regulates Vegfr3 and is required for lymphatic vessel development.

Lymphatic dysfunction causes several human diseases, and tumor lymphangiogenesis is implicated in cancer spreading. TBX1 is the major gene for DiGeorge syndrome, which is associated with multiple congenital anomalies. Mutation of Tbx1 in mice recapitulates the human disease phenotype.

Exploring death receptor pathways as selective targets in cancer therapy.

A recent and innovative strategy in cancer therapy is the activation of apoptosis in tumour cells specifically expressing death receptors (DR) belonging to the tumour necrosis factor (TNF) receptor superfamily and including several members known since the early '90. Among these, those largely studied for clinical purpose are TNF, CD95, and TRAIL receptors. Promising results are expecting from ongoing phases I/II clinical trials proving the therapeutic efficacy of DR agonistic antibodies and/or recombinant proteins alone or in association to classic and novel chemotherapeutic drugs.

Fgf8 expression in the Tbx1 domain causes skeletal abnormalities and modifies the aortic arch but not the outflow tract phenotype of Tbx1 mutants.

Fgf8 and Tbx1 have been shown to interact in patterning the aortic arch, and both genes are required in formation and growth of the outflow tract of the heart. However, the nature of the interaction of the two genes is unclear. We have utilized a novel Tbx1(Fgf8) allele which drives Fgf8 expression in Tbx1-positive cells and an inducible Cre-LoxP recombination system to address the role of Fgf8 in Tbx1 positive cells in modulating cardiovascular development.

Tbx1 haploinsufficiency is linked to behavioral disorders in mice and humans: implications for 22q11 deletion syndrome.

About 35% of patients with 22q11 deletion syndrome (22q11DS), which includes DiGeorge and velocardiofacial syndromes, develops psychiatric disorders, mainly schizophrenia and bipolar disorder. We previously reported that mice carrying a multigene deletion (Df1) that models 22q11DS have reduced prepulse inhibition (PPI), a behavioral abnormality and schizophrenia endophenotype. Impaired PPI is associated with several psychiatric disorders, including those that occur in 22q11DS, and recently, reduced PPI was reported in children with 22q11DS.

Biochemical and functional characterization of protein kinase CK2 in ascidian Ciona intestinalis oocytes at fertilization. Cloning and sequence analysis of cDNA for alpha and beta subunits.

The ubiquitous and pleiotropic dual specificity protein kinase CK2 has been studied and characterized in many organisms, from yeast to mammals. Generally, the enzyme is composed of two catalytic (alpha and/or alpha') and two regulatory (beta) subunits, forming a differently assembled tetramer. Although prone to controversial interpretation, the function of CK2 has been associated with fundamental biological processes such as signal transduction, cell cycle progression, cell growth, apoptosis, and transcription.

Flavonoid quercetin sensitizes a CD95-resistant cell line to apoptosis by activating protein kinase Calpha.

We previously demonstrated that quercetin, a naturally occurring flavonoid with strong antioxidant properties, was able to enhance programmed cell death in HPB-acute lymphoblastic leukemia (ALL) cell line, derived from a human tymoma, when associated with the agonistic anti-CD95 monoclonal antibody. Here, we report that HPB-ALL cells are normally resistant to CD95-mediated apoptosis, and quercetin is able to sensitize this cell line through a mechanism independent of its antioxidant properties. In fact, other compounds structurally and functionally similar to quercetin, when associated with anti-CD95 antibody did not induce any CD95-mediated apoptosis, still maintaining their antioxidant capacity.