Inhibition of pyrimidine biosynthesis targets protein translation in acute myeloid leukemia.

The mitochondrial enzyme dihydroorotate dehydrogenase (DHODH) catalyzes one of the rate-limiting steps in de novo pyrimidine biosynthesis, a pathway that provides essential metabolic precursors for nucleic acids, glycoproteins, and phospholipids. DHODH inhibitors (DHODHi) are clinically used for autoimmune diseases and are emerging as a novel class of anticancer agents, especially in acute myeloid leukemia (AML) where pyrimidine starvation was recently shown to reverse the characteristic differentiation block in AML cells. Herein, we show that DHODH blockade rapidly shuts down protein translation in leukemic stem cells (LSCs) and has potent and selective activity against multiple AML subtypes.

Epigenetic Activation of Plasmacytoid DCs Drives IFNAR-Dependent Therapeutic Differentiation of AML.

Unlabelled: Pharmacologic inhibition of epigenetic enzymes can have therapeutic benefit against hematologic malignancies. In addition to affecting tumor cell growth and proliferation, these epigenetic agents may induce antitumor immunity. Here, we discovered a novel immunoregulatory mechanism through inhibition of histone deacetylases (HDAC).

A Histone Deacetylase Inhibitor, Panobinostat, Enhances Chimeric Antigen Receptor T-cell Antitumor Effect Against Pancreatic Cancer.

Purpose: In this article, we describe a combination chimeric antigen receptor (CAR) T-cell therapy that eradicated the majority of tumors in two immunocompetent murine pancreatic cancer models and a human pancreatic cancer xenograft model.

Experimental Design: We used a dual-specific murine CAR T cell that expresses a CAR against the Her2 tumor antigen, and a T-cell receptor (TCR) specific for gp100. As gp100 is also known as pMEL, the dual-specific CAR T cells are thus denoted as CARaMEL cells.

CDK4/6 Inhibition Promotes Antitumor Immunity through the Induction of T-cell Memory.

Pharmacologic inhibitors of cyclin-dependent kinases 4 and 6 (CDK4/6) are an approved treatment for hormone receptor-positive breast cancer and are currently under evaluation across hundreds of clinical trials for other cancer types. The clinical success of these inhibitors is largely attributed to well-defined tumor-intrinsic cytostatic mechanisms, whereas their emerging role as immunomodulatory agents is less understood. Using integrated epigenomic, transcriptomic, and proteomic analyses, we demonstrated a novel action of CDK4/6 inhibitors in promoting the phenotypic and functional acquisition of immunologic T-cell memory.

TET2 deficiency reprograms the germinal center B cell epigenome and silences genes linked to lymphomagenesis.

The TET2 DNA hydroxymethyltransferase is frequently disrupted by somatic mutations in diffuse large B cell lymphomas (DLBCLs), a tumor that originates from germinal center (GC) B cells. Here, we show that TET2 deficiency leads to DNA hypermethylation of regulatory elements in GC B cells, associated with silencing of the respective genes. This hypermethylation affects the binding of transcription factors including those involved in exit from the GC reaction and involves pathways such as B cell receptor, antigen presentation, CD40, and others.

Portal Angiogenesis in Chronic Liver Disease Patients Correlates with Portal Pressure and Collateral Formation.

Background/aims: One hallmark of chronic liver disease in patients with portal hypertension is the formation of portal-systemic collaterals in which angiogenesis has a fundamental role. We studied patients with chronic liver disease undergoing liver transplantation to correlate levels of circulating angiogenic factors in portal and peripheral circulation with portal pressure and portal-systemic collaterals.

Methods: Sixteen patients who underwent liver transplantation were enrolled.

TET2 Deficiency Causes Germinal Center Hyperplasia, Impairs Plasma Cell Differentiation, and Promotes B-cell Lymphomagenesis.

somatic mutations occur in ∼10% of diffuse large B-cell lymphomas (DLBCL) but are of unknown significance. Herein, we show that TET2 is required for the humoral immune response and is a DLBCL tumor suppressor. TET2 loss of function disrupts transit of B cells through germinal centers (GC), causing GC hyperplasia, impaired class switch recombination, blockade of plasma cell differentiation, and a preneoplastic phenotype.

Extracellular vesicles in DLBCL provide abundant clues to aberrant transcriptional programming and genomic alterations.

The biological role of extracellular vesicles (EVs) in diffuse large B-cell lymphoma (DLBCL) initiation and progression remains largely unknown. We characterized EVs secreted by 5 DLBCL cell lines, a primary DLBCL tumor, and a normal control B-cell sample, optimized their purification, and analyzed their content. We found that DLBCLs secreted large quantities of CD63, Alix, TSG101, and CD81 EVs, which can be extracted using an ultracentrifugation-based method and traced by their cell of origin surface markers.

Liver X Receptor Nuclear Receptors Are Transcriptional Regulators of Dendritic Cell Chemotaxis.

The liver X receptors (LXRs) are ligand-activated nuclear receptors with established roles in the maintenance of lipid homeostasis in multiple tissues. LXRs exert additional biological functions as negative regulators of inflammation, particularly in macrophages. However, the transcriptional responses controlled by LXRs in other myeloid cells, such as dendritic cells (DCs), are still poorly understood.

AICDA drives epigenetic heterogeneity and accelerates germinal center-derived lymphomagenesis.

Epigenetic heterogeneity is emerging as a feature of tumors. In diffuse large B-cell lymphoma (DLBCL), increased cytosine methylation heterogeneity is associated with poor clinical outcome, yet the underlying mechanisms remain unclear. Activation-induced cytidine deaminase (AICDA), an enzyme that mediates affinity maturation and facilitates DNA demethylation in germinal center (GC) B cells, is required for DLBCL pathogenesis and linked to inferior outcome.

The new frontier of epigenetic heterogeneity in B-cell neoplasms.

Purpose Of Review: There is mounting evidence that heterogeneity of the epigenome is a feature of many cancers, including B-cell lymphomas, and presents important clinical implications. The purpose of this review is to explain the biological and clinical relevance of this epigenetic phenomenon in B-cell neoplasms.

Recent Findings: Here, we summarize new findings demonstrating that B-cell lymphomas display increased DNA methylation heterogeneity compared to their normal counterparts.

The many layers of epigenetic dysfunction in B-cell lymphomas.

Purpose Of Review: Perturbation of the epigenome is emerging as a central driving force in the pathogenesis of diffuse large B-cell lymphomas (DLBCL) and follicular lymphoma. The purpose of this review is to explain how alteration of different layers of the epigenome contributes to the biology and clinical features of these tumors.

Recent Findings: Key new findings implicate DNA methylation heterogeneity as a core feature of DLBCL.

DNA Methylation Dynamics of Germinal Center B Cells Are Mediated by AID.

Changes in DNA methylation are required for the formation of germinal centers (GCs), but the mechanisms of such changes are poorly understood. Activation-induced cytidine deaminase (AID) has been recently implicated in DNA demethylation through its deaminase activity coupled with DNA repair. We investigated the epigenetic function of AID in vivo in germinal center B cells (GCBs) isolated from wild-type (WT) and AID-deficient (Aicda(-/-)) mice.

A team-based multidisciplinary approach to managing peripherally inserted central catheter complications in high-risk haematological patients: a prospective study.

Purpose: Use of peripherally inserted central catheters (PICCs) has markedly increased during the last decade. However, there are few studies on use of PICCs in patients with haematological malignancies (HM) receiving intensive chemotherapy. Preliminary data suggest a higher rate of PICC-related complications in these high-risk patients.

[Outcomes using two preservation solutions (UW/HTK) in liver transplantation from brain death donors].

Background: Preservation solutions are critical for organ transplantation. In liver transplant (LT), the solution developed by the University Of Wisconsin (UW) is the gold-standard to perfuse deceased brain death donor (DBD) grafts. Histidine-Tryptophan-Ketoglutarate (HTK), formerly a cardioplegic infusion, has been also used in solid organ transplantation.

Epigenetic function of activation-induced cytidine deaminase and its link to lymphomagenesis.

Activation-induced cytidine deaminase (AID) is essential for somatic hypermutation and class switch recombination of immunoglobulin (Ig) genes during B cell maturation and immune response. Expression of AID is tightly regulated due to its mutagenic and recombinogenic potential, which is known to target not only Ig genes, but also non-Ig genes, contributing to lymphomagenesis. In recent years, a new epigenetic function of AID and its link to DNA demethylation came to light in several developmental systems.

IL-4 blocks TH1-polarizing/inflammatory cytokine gene expression during monocyte-derived dendritic cell differentiation through histone hypoacetylation.

Background: Whereas recent research has characterized the mechanism by which dendritic cells (DCs) induce T(H)1/T(H)17 responses, the functional specialization enabling DCs to polarize T(H)2 responses remains undefined. Because IL-4 is essential during T(H)2 responses not only by acting on CD4(+) T cells through the activation of GATA-3 but also by regulating IgE class-switching, epithelial cell permeability, and muscle contractility, we hypothesized that IL-4 could also have a role in the conditioning of DCs during T(H)2 responses.

Objective: We sought to analyze whether IL-4 exerts an immunomodulatory function on DCs during their differentiation, leading to their functional specialization for the induction of T(H)2 responses.

Steatotic livers. Can we use them in OLTX? Outcome data from a prospective baseline liver biopsy study.

Introduction: Steatotic livers have been associated with greater risk of allograft dysfunction in liver transplantation. Our aim was to determinate the prevalence of steatosis in grafts from deceased donors in Chile and to assess the utility of a protocol-bench biopsy as an outcome predictor of steatotic grafts in our transplant program.

Material And Methods: We prospectively performed protocol-bench graft biopsies from March 2004 to January 2009.

[Treatment of the patient with castration-resistant biochemical progression of prostate cancer].

Castration resistant prostatic carcinoma (CRPC) is defined as tumor progression despite an effective castration (serum testosterone levels < 50 ng/dL). Biochemical progression requires at least two successive increases from the previous lowest value of serum prostate-specific antigen (PSA) spaced at least a week, and with a minimum value of 2 ng/mL. In patients receiving complete androgen blockade, antiandrogen should be discontinued prior to diagnosis of CRPC.

Statins inhibit iNOS-mediated microbicidal potential of activated monocyte-derived dendritic cells by an IFN-β-dependent mechanism.

Statins are prescribed to 25 million people worldwide for treating hypercholesterolemia and reducing the risk of cardiovascular diseases. However, the side effects of statins on immunity, and particularly on DC immunobiology, have not been analyzed in-depth. Here, we have investigated the impact of lovastatin treatment during monocyte differentiation into DCs on the responsiveness of the resulting monocyte-derived DCs (moDCs) to TLR-mediated activation.

Operational tolerance after liver transplantation, more common than we think: a case report.

Operational tolerance after liver transplantation has been described in around 20% of the recipients. These patients are able to maintain a normal graft function in the absence of immunosuppressive drugs, thus being free of adverse effects that are common and frequently severe. Here we present a well-documented case of operational tolerance after liver transplantation and discuss current concepts on this topic with emphasis on recent findings that will potentially allow for identifying graft-tolerant patients.

Differentiation and function of mouse monocyte-derived dendritic cells in steady state and inflammation.

Although monocytes were originally described as precursors to all the different subpopulations of macrophages found in the steady state and formed under inflammatory and infectious conditions, recent data have demonstrated conclusively that monocytes can also differentiate into dendritic cells (DCs). Monocytes are the precursors to different subsets of DCs, such as Langerhans cells and DCs found in the lamina propria of the gastrointestinal, respiratory, and urogenital tracts. In addition, monocyte-derived DCs (moDCs), newly formed during inflammatory reactions, appear to fulfill an essential role in defense mechanisms against pathogens by participating in the induction of both adaptive and innate immune responses.

[Intravascular hypothermia for the management of Intracranial hypertension in acute liver failure: case report].

Acute liver failure has a mortality rate in excess of 80%. Most deaths are attributed to brain edema with intracranial hypertension and herniation of structures, where ammonium plays a major role in its generation. We report an 18 year-old female with a fulminant hepatic failure caused by virus A infection.

Successful treatment of severe hepatopulmonary syndrome with a sequential use of TIPS placement and liver transplantation.

Unlabelled: Hepatopulmonary syndrome (HPS) is a complication of portal hypertension (PH) defined by the presence of liver disease, abnormal pulmonary gas exchange and evidence of intrapulmonary vascular dilatations (IPVD) producing a right to left intrapulmonary shunt. Liver transplantation (LT) is the treatment of choice; however, severe hypoxemia may contraindicate LT. The use of transjugular intrahepatic portosystemic shunts (TIPS) could be effective in HPS, although available data is limited.