Targeting sphingolipid metabolism in chronic lymphocytic leukemia.

Elevated levels of circulating C16:0 glucosylceramides (GluCer) and increased mRNA expression of UDP-glucose ceramide glycosyltransferase (UGCG), the enzyme responsible for converting ceramides (Cer) to GluCer, represent unfavorable prognostic markers in chronic lymphocytic leukemia (CLL) patients. To evaluate the therapeutic potential of inhibiting GluCer synthesis, we genetically repressed the UGCG pathway using in vitro models of leukemic B cells, in addition to UGCG pharmacological inhibition with approved drugs such as eliglustat and ibiglustat, both individually and in combination with ibrutinib, assessed in cell models and primary CLL patient cells. Cell viability, apoptosis, and proliferation were evaluated in vitro, and survival and apoptosis were examined ex vivo.

Untargeted metabolomics identifies metabolic dysregulation of sphingolipids associated with aggressive chronic lymphocytic leukaemia and poor survival.

Background: Metabolic dependencies of chronic lymphocytic leukaemia (CLL) cells may represent new personalized treatment approaches in patients harbouring unfavourable features.

Methods: Here, we used untargeted metabolomics and lipidomics analyses to isolate metabolomic features associated with aggressive CLL and poor survival outcomes. We initially focused on profiles associated with overexpression of the adverse metabolic marker glycosyltransferase (UGT2B17) associated with poor survival and drug resistance.

A Non-Canonical Role for the Glycosyltransferase Enzyme UGT2B17 as a Novel Constituent of the B Cell Receptor Signalosome.

In chronic lymphocytic leukemia (CLL), an elevated glycosyltransferase UGT2B17 expression (UGT2B17) identifies a subgroup of patients with shorter survival and poor drug response. We uncovered a mechanism, possibly independent of its enzymatic function, characterized by an enhanced expression and signaling of the proximal effectors of the pro-survival B cell receptor (BCR) pathway and elevated Bruton tyrosine kinase (BTK) phosphorylation in B-CLL cells from UGT2B17 patients. A prominent feature of B-CLL cells is the strong correlation of UGT2B17 expression with the adverse marker ZAP70 encoding a tyrosine kinase that promotes B-CLL cell survival.

Core-binding factor leukemia hijacks the T-cell-prone PU.1 antisense promoter.

The blood system serves as a key model for cell differentiation and cancer. It is orchestrated by precise spatiotemporal expression of crucial transcription factors. One of the key master regulators in the hematopoietic systems is PU.

Higher-order connections between stereotyped subsets: implications for improved patient classification in CLL.

Chronic lymphocytic leukemia (CLL) is characterized by the existence of subsets of patients with (quasi)identical, stereotyped B-cell receptor (BcR) immunoglobulins. Patients in certain major stereotyped subsets often display remarkably consistent clinicobiological profiles, suggesting that the study of BcR immunoglobulin stereotypy in CLL has important implications for understanding disease pathophysiology and refining clinical decision-making. Nevertheless, several issues remain open, especially pertaining to the actual frequency of BcR immunoglobulin stereotypy and major subsets, as well as the existence of higher-order connections between individual subsets.

UGT2B17 modifies drug response in chronic lymphocytic leukaemia.

Background: High UGT2B17 is associated with poor prognosis in untreated chronic lymphocytic leukaemia (CLL) patients and its expression is induced in non-responders to fludarabine-containing regimens. We examined whether UGT2B17, the predominant lymphoid glucuronosyltransferase, affects leukaemic drug response and is involved in the metabolic inactivation of anti-leukaemic agents.

Methods: Functional enzymatic assays and patients' plasma samples were analysed by mass-spectrometry to evaluate drug inactivation by UGT2B17.

Inactivation of Prostaglandin E as a Mechanism for UGT2B17-Mediated Adverse Effects in Chronic Lymphocytic Leukemia.

High expression of the metabolic enzyme UDP-glucuronosyltransferase UGT2B17 in chronic lymphocytic leukemia (CLL) cells was associated with poor prognosis in two independent studies. However, the underlying mechanism remains unknown. We hypothesized that UGT2B17 impacts intracellular levels of hormone-like signaling molecules involved in the regulation of gene expression in leukemic cells.

Signatures of CD8+ T cell dysfunction in AML patients and their reversibility with response to chemotherapy.

Background: Our understanding of phenotypic and functional signatures of CD8+ T cell dysfunction in acute myeloid leukemia (AML) is limited. Deciphering these deranged T cell functional states and how they are impacted by induction chemotherapy is essential for incorporation of novel immune-based strategies to restore and maintain antileukemia immunity.

Methods: We utilized high-dimensional immunophenotyping, gene expression, and functional studies to characterize peripheral blood and bone marrow CD8+ T cells in 72 AML patients at diagnosis and after induction chemotherapy.

Sex-dependent association of circulating sex steroids and pituitary hormones with treatment-free survival in chronic lymphocytic leukemia patients.

Chronic lymphocytic leukemia (CLL) is not considered a hormone-regulated cancer although sex is a recognized risk factor with men more frequently diagnosed and developing progressive disease. We hypothesized that variable hormonal exposure may have a sexually dimorphic influence on treatment-free survival (TFS). In 156 CLL cases, we quantitatively profiled 29 circulating steroids (progesterone, adrenal precursors, androgens, estrogens, and catechol estrogens) as well as luteinizing hormone (LH) and follicle-stimulating hormone.

Cannabinoid Receptors Are Overexpressed in CLL but of Limited Potential for Therapeutic Exploitation.

The cannabinoid receptors 1 and 2 (CNR1&2) are overexpressed in a variety of malignant diseases and cannabinoids can have noteworthy impact on tumor cell viability and tumor growth. Patients diagnosed with chronic lymphocytic leukemia (CLL) present with very heterogeneous disease characteristics translating into highly differential risk properties. To meet the urgent need for refinement in risk stratification at diagnosis and the search for novel therapies we studied CNR expression and response to cannabinoid treatment in CLL.

Pre-BCR signaling in precursor B-cell acute lymphoblastic leukemia regulates PI3K/AKT, FOXO1 and MYC, and can be targeted by SYK inhibition.

Precursor-B-cell receptor (pre-BCR) signaling and spleen tyrosine kinase (SYK) recently were introduced as therapeutic targets for patients with B-cell acute lymphoblastic leukemia (B-ALL), but the importance of this pathway in B-ALL subsets and mechanism of downstream signaling have not fully been elucidated. Here, we provide new detailed insight into the mechanism of pre-BCR signaling in B-ALL. We compared the effects of pharmacological and genetic disruption of pre-BCR signaling in vitro and in mouse models for B-ALL, demonstrating exquisite dependency of pre-BCR(+) B-ALL, but not other B-ALL subsets, on this signaling pathway.

SAR-guided development and characterization of a potent antitumor compound toward B-cell neoplasms with no detectable cytotoxicity toward healthy cells.

Acute hematological diseases (leukemias and aggressive lymphomas) can be cured in approximately half of the patients, while the other patients die from their disease. Chronic leukemias and indolent lymphomas can be well controlled for years in most cases. However, the cure rate of these patients is low and the course of the disease is characterized by frequent recurrence.

Lupus anticoagulant and thrombosis in splenic marginal zone lymphoma.

Introduction: Splenic marginal zone lymphoma (SMZL) is a rare low-malignant Non-Hodgkin lymphoma (NHL), in which immune mediated paraneoplastic phenomena such as autoimmune hemolytic anemia (AIHA), autoimmune thrombocytopenia (ITP) and C1 esterase inhibitor deficiency are relatively common.

Materials And Methods: We performed a multicenter retrospective study in 70 patients on the prevalence and clinical features of antiphospholipid antibodies (aPLA) in SMZL.

Results And Conclusions: Nine patients (13%) had the diagnosis of a lupus anticoagulant (LA).

The Runx-PU.1 pathway preserves normal and AML/ETO9a leukemic stem cells.

Runx transcription factors contribute to hematopoiesis and are frequently implicated in hematologic malignancies. All three Runx isoforms are expressed at the earliest stages of hematopoiesis; however, their function in hematopoietic stem cells (HSCs) is not fully elucidated. Here, we show that Runx factors are essential in HSCs by driving the expression of the hematopoietic transcription factor PU.

Chronic lymphocytic leukemia patients have a preserved cytomegalovirus-specific antibody response despite progressive hypogammaglobulinemia.

Chronic lymphocytic leukemia (CLL) is characterized by progressive hypogammaglobulinemia predisposing affected patients to a variety of infectious diseases but paradoxically not to cytomegalovirus (CMV) disease. Moreover, we found reactivity of a panel of CLL recombinant antibodies (CLL-rAbs) encoded by a germ-line allele with a single CMV protein, pUL32, despite differing antibody binding motifs. To put these findings into perspective, we studied prospectively relative frequency of viremia, kinetics of total and virus-specific IgG over time, and UL32 genetic variation in a cohort of therapy-naive patients (n=200).

UDP-glucuronosyltransferase 2B17 genotype and the risk of lung cancer among Austrian Caucasians.

Background: The enzyme uridine diphospho glucuronosyltansferase 2B17 (UGT2B17) glucuronidates several endogenous and exogenous compounds, including carcinogens from tobacco smoke like 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanl (NNAL). UGT2B17 shows a remarkable copy number variation (CNV) and an association between deletion genotype and increased risk of lung adenocarcinoma in women has been previously reported.

Methods: We investigated the UGT2B17 CNV by PCR in 453 Austrian lung cancer patients and in 449 healthy donors and analyzed the impact on lung cancer susceptibility and outcome.

Lipoprotein lipase in chronic lymphocytic leukaemia - strong biomarker with lack of functional significance.

In chronic lymphocytic leukaemia (CLL), lipoprotein lipase (LPL) mRNA overexpression is an established poor prognostic marker, its function, however, is poorly understood. Measuring extracellular LPL enzymatic activity and protein, we found no difference between levels in CLL patients and those of controls, both before and after heparin treatment in vivo and in vitro. Investigating LPL knock down effects, we determined five potential downstream targets, of which one gene, STXBP3, reportedly is involved in fatty acid metabolism.

Overexpression of uridine diphospho glucuronosyltransferase 2B17 in high-risk chronic lymphocytic leukemia.

Uridine diphospho glucuronosyltransferase 2B17 (UGT2B17) glucuronidates androgens and xenobiotics including certain drugs. The UGT2B17 gene shows a remarkable copy number variation (CNV), which predisposes for solid tumors and influences drug response. Here, we identify a yet undescribed UGT2B17 mRNA overexpression in poor-risk chronic lymphocytic leukemia (CLL).

Recombinant antibodies encoded by IGHV1-69 react with pUL32, a phosphoprotein of cytomegalovirus and B-cell superantigen.

Leukemia cells from patients with chronic lymphocytic leukemia (CLL) express a highly restricted immunoglobulin heavy variable chain (IGHV) repertoire, suggesting that a limited set of antigens reacts with leukemic cells. Here, we evaluated the reactivity of a panel of different CLL recombinant antibodies (rAbs) encoded by the most commonly expressed IGHV genes with a panel of selected viral and bacterial pathogens. Six different CLL rAbs encoded by IGHV1-69 or IGHV3-21, but not a CLL rAb encoded by IGHV4-39 genes, reacted with a single protein of human cytomegalovirus (CMV).

Prolonged progression-free survival in patients with chronic lymphocytic leukemia receiving granulocyte colony-stimulating factor during treatment with fludarabine, cyclophosphamide, and rituximab.

The clinical benefit of the addition of granulocyte colony-stimulating factor (G-CSF) to standard immunochemotherapy of chronic lymphocytic leukemia (CLL) with fludarabine, cyclophosphamide, and rituximab (FCR) is still unclear. In this retrospective study we analyzed the outcome of 32 consecutive patients with CLL during treatment with FCR. Sixteen patients received G-CSF for treatment of CTC grade 3 or 4 neutropenia or febrile neutropenia at some point during therapy and 16 did not.