The membrane proteins CD38 and CD157 belong to an evolutionarily conserved family of enzymes that play crucial roles in human physiology. Expressed in distinct patterns in most tissues, CD38 (and CD157) cleaves NAD(+) and NADP(+), generating cyclic ADP ribose (cADPR), NAADP, and ADPR. These reaction products are essential for the regulation of intracellular Ca(2+), the most ancient and universal cell signaling system. The entire family of enzymes controls complex processes, including egg fertilization, cell activation and proliferation, muscle contraction, hormone secretion, and immune responses. Over the course of evolution, the molecules have developed the ability to interact laterally and frontally with other surface proteins and have acquired receptor-like features. As detailed in this review, the loss of CD38 function is associated with impaired immune responses, metabolic disturbances, and behavioral modifications in mice. CD38 is a powerful disease marker for human leukemias and myelomas, is directly involved in the pathogenesis and outcome of human immunodeficiency virus infection and chronic lymphocytic leukemia, and controls insulin release and the development of diabetes. Here, the data concerning diseases are examined in view of potential clinical applications in diagnosis, prognosis, and therapy. The concluding remarks try to frame all of the currently available information within a unified working model that takes into account both the enzymatic and receptorial functions of the molecules.

Notch2 mutations represent the most frequent lesion in splenic marginal zone lymphoma.

The genetic lesions identified in chronic lymphocytic leukemia (CLL) do not entirely recapitulate the disease pathogenesis and the development of serious complications, such as chemorefractoriness. While investigating the coding genome of fludarabine-refractory CLL, we observed that mutations of SF3B1, encoding a splicing factor and representing a critical component of the cell spliceosome, were recurrent in 10 of 59 (17%) fludarabinerefractory cases, with a frequency significantly greater than that observed in a consecutive CLL cohort sampled at diagnosis (17/301, 5%; P ‫؍‬ .002). Mutations were somatically acquired, were generally represented by missense nucleotide changes, clustered in selected HEAT repeats of the SF3B1 protein, recurrently targeted 3 hotspots (codons 662, 666, and 700), and were predictive of a poor prognosis. In fludarabine-refractory CLL, SF3B1 mutations and TP53 disruption distributed in a mutually exclusive fashion (P ‫؍‬ . IntroductionThe clinical course of chronic lymphocytic leukemia (CLL) ranges from a very indolent disorder with a normal lifespan for the patient to a rapidly progressive disease that leads to death. Occasionally, CLL undergoes a transformation to Richter syndrome (RS). [1][2][3] The variable clinical course of CLL is driven, at least in part, by the disease's immunogenetic and molecular heterogeneity. 4 Despite recent advances, the genetic lesions identified to date do not fully recapitulate the molecular pathogenesis of CLL and do not entirely explain the development of severe complications, such as chemorefractoriness, which still represent unmet clinical needs. 5 In approximately 40% of cases, refractoriness to fludarabine is attributable to the disruption of TP53, but in a sizeable fraction of patients, the molecular basis of this aggressive phenotype remains unclear. 6 Recently, 2 independent studies of the CLL coding genome investigated at disease presentation have revealed a restricted number of mutated genes, including NOTCH1. 7,8 These studies have provided a proof of concept that, similar to other malignancies, genome-wide mutational analysis might identify novel lesions of biologic and clinical relevance in CLL. On these grounds, we have embarked on the investigation of the coding genome of fludarabine-refractory CLL to identify genetic lesions associated with chemorefractoriness. The initial phases of this analysis have revealed recurrent mutations of SF3B1, a critical component of the cell spliceosome, pointing to the potential involvement of splicing regulation in CLL pathogenesis and chemorefractoriness. Methods PatientsThe study population comprised 3 cohorts representative of different disease phases: (1) fludarabine-refractory CLL (n ϭ 59), including cases (n ϭ 11) subjected to whole-exome sequencing (supplemental Table 1, available on the Blood Web site; see the Supplemental Materials link at the top of the online article); (2) a consecutive series of newly diagnosed and previously untreated patients with CLL (n ϭ 301; supplemental Table 2 For pers...

The genetic lesions identified to date do not fully recapitulate the molecular pathogenesis of chronic lymphocytic leukemia (CLL) and do not entirely explain the development of severe complications such as chemorefractoriness. In the present study, BIRC3, a negative regulator of noncanonical NF-B signaling, was investigated in different CLL clinical phases.

No abstract

CD38, an ectoenzyme and a signaling receptor, is a novel marker of human mature monocyte-derived dendritic cells (MDDCs). The working hypothesis is that CD38 is not only a marker but also contributes to functions specifically gained by MDDCs with maturation. This was tested by assessing the role(s) of CD38 after signaling with agonistic anti-CD38 monoclonal antibodies or by blocking the interactions taking place between CD38 and CD31, its counterreceptor. IntroductionCD38 is a pleiotropic cell surface molecule acting as an ectoenzyme and a receptor. The enzymatic activity ends in the synthesis of Ca 2ϩ -mobilizing metabolites (ie, ADP-ribose [ADPR], nicotinic acid adenine dinucleotide phosphate [NAADP], and cyclic ADP-ribose [cADPR]) involved in the regulation of calcium-dependent calcium release. 1,2 CD38 has a unique pattern of surface expression among cells of the human immune system, being present on lymphoid and myeloid progenitors, lost during differentiation, and re-expressed at high density in activated T, B, and natural killer (NK) cells. 3,4 The molecule shows a broad distribution in different tissues. 5 CD38 ligation in immune cells delivers activation signals and induces cytokine production and secretion by T, 6 B, 7 and NK cells 8 and monocytes. 9 CD38 also regulates cell viability by preventing human germinal center B cells from undergoing apoptosis 10 and contributing to increased survival of B-cell chronic lymphocytic leukemia (B-CLL) cells. 11 This panoply of different functional roles may be explained considering some nonconventional features of CD38 as a receptor. The intrinsic ineptitude of CD38 to transduce signals is overcome by working in physical and functional associations with specialized signaling molecules, such as T-cell receptor on T cells, 12-14 B-cell receptor on B cells, 15,16 and CD16 on NK cells. 17 CD38 can sustain adhesion and rolling of CD38 ϩ lymphocytes on endothelial cells through interaction with CD31 (identified as a specific counterreceptor 18 ), suggesting its possible role in lymphocyte trafficking. 19 All the signals mediated by monoclonal antibody (mAb) ligation of CD38 can be reproduced by its interaction with CD31.In murine models, CD38 is involved in chemotaxis and transendothelial migration of both polymorphonuclear leukocytes (PMNs) and dendritic cells (DCs) and this function requires its enzymatic activities. 20,21 Consequently, CD38 knockout mice have impaired capacity to respond to infections. 20 The evaluation of the expression of the molecule also has applications in clinical diagnosis, such as in AIDS (where CD38 is one of the earliest indicators of infection 22 ) and B-CLL (where the expression is generally associated with poor prognosis 15 ). Autoantibodies specific for CD38 are found in diabetes and thyroid disorders. [23][24][25][26] The agonistic properties of these autoantibodies envisage pathogenic role(s) in these diseases.We recently reported a pulsatile pattern of surface CD38 expression in human monocyte-derived dendritic cells (MDDCs). 27 ...

IntroductionKnowledge of the pathogenesis of splenic marginal zone lymphoma (SMZL) is scarce. 1,2 On the basis of clinical and epidemiologic data, hepatitis C virus infection might play a role in a fraction of SMZLs. 1,2 The contribution of antigen stimulation is suggested by the highly restricted immunoglobulin gene repertoire and by the stereotyped B-cell receptor in ϳ 10% of SMZLs. 3,4 Cancer genes involved in SMZL pathogenesis are currently unknown, except for TP53 disruption in ϳ 10%-15% of cases. 3,5 Indirect evidence points to nuclear factor-B (NF-B) pathway genes as attractive candidates in SMZL. Abnormal marginal zone B-cell expansions are observed frequently in animal models with constitutive NF-B activation. [6][7][8] In addition, up-regulated expression of NF-B target genes in SMZL suggests the occurrence of NF-B activation, 9 which in other B-cell malignancies is sustained by cancer-specific genetic lesions. 10,11 This rationale prompted the assessment of NF-B genetic alterations in SMZL. We document that the canonical and noncanonical NF-B pathways are affected by multiple genetic lesions in Ͼ 30% of SMZLs. Methods Patient samplesThe study was based on 101 SMZLs diagnosed according to World Health Organization classification and SMZL Working Party criteria (supplemental Table 1, available on the Blood Web site; see the Supplemental Materials link at the top of the online article). 1,2 Matched germline DNA was extracted from saliva. Patients provided informed consent in accordance with local institutional review board requirements and the Declaration of Helsinki. The study was approved by the ethics committee of the Amedeo Avogadro University. Molecular studiesMutation analysis of 20 NF-B pathway genes (supplemental Table 2; supplemental Figure 1) and TP53 was performed by DNA Sanger sequencing. Copy number abnormalities (CNAs) of NF-B genes and TP53 were analyzed by FISH (probes in supplemental Table 2) and single-nucleotide polymorphism array (GeneChip Human Mapping 250K NspI, Affymetrix; Gene Expression Omnibus accession number GSE24881). Western blot studies B cells from SMZL spleens were purified by negative selection with Dynal magnetic beads (Invitrogen). Proteins were resolved by SDS-PAGE and analyzed by Western blot. Antibodies were anti-NFKB2 (Cell Signaling, #4882), anti-MAP3K14 (Cell Signaling, #4994), and anti-actin (Santa Cruz Biotechnology, #sc-1615). Image acquisition and densitometric analyses were performed with ImageQuant LAS4000 and TL software (GE Healthcare). Results and discussionSMZLs were characterized for active NF-B signaling by immunohistochemical assays that detected nuclear NFKB1 (p50) and NFKB2 (p52). 10 Nuclear localization of NF-B was observed in tumor cells of 14 (58%) of 24 SMZLs ( Figure 1A-B). Both canonical (11/24, 46%) and noncanonical (4/24, 17%) NF-B pathways were activated. One patient showed activation of both pathways. Engagement of the noncanonical NF-B pathway was confirmed by biochemical detection of NFKB2 processing ( Figure 1C).To investigate the m...

Key Points• CLL lymphocytes show high intracellular and extracellular NAMPT levels, further increased upon activation.• eNAMPT prompts differentiation of CLL monocytes into M2 macrophages that sustain CLL survival and reduce T-cell proliferation.Nicotinamide phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme in nicotinamide adenine dinucleotide biosynthesis. In the extracellular compartment, it exhibits cytokine-/adipokinelike properties, suggesting that it stands at the crossroad between metabolism and inflammation. Here we show that both intracellular and extracellular NAMPT levels are increased in cells and plasma of chronic lymphocytic leukemia (CLL) patients. The extracellular form (eNAMPT) is produced by CLL lymphocytes upon B-cell receptor, Toll-like receptor, and nuclear factor kB (NF-kB) signaling pathway activation. eNAMPT is important for differentiation of resting monocytes, polarizing them toward tumor-supporting M2 macrophages. These cells express high levels of CD163, CD206, and indoleamine 2,3-dioxygenase and secrete immunosuppressive (interleukin [IL] 10, CC chemokine ligand 18) and tumor-promoting (IL-6, IL-8) cytokines. NAMPT-primed M2 macrophages activate extracellular-regulated kinase 1/2, signal transducer and activator of transcription 3, and NF-kB signaling; promote leukemic cell survival; and reduce T-cell responses. These effects are independent of the enzymatic activity of NAMPT, as inferred from the use of an enzymatically inactive mutant. Overall, these results reveal that eNAMPT is a critical element in the induction of an immunosuppressive and tumor-promoting microenvironment of CLL. (Blood. 2015;125(1):111-123) IntroductionBesides being the first line of defense against pathogens, macrophages orchestrate tissue plasticity and homeostasis. They are classified into classically activated (M1) or alternatively activated (M2) macrophages, reflecting a different functional role. 1 In cancer tissues, macrophages tend to be of the M2 phenotype, acquired and maintained through multiple interactions with tumor cells.2 Evidence indicates that these macrophages enhance tumor progression, mainly through the secretion of chemokines/cytokines that sustain neoplastic the cell proliferation and suppress immune responses. 3,4 Chronic lymphocytic leukemia (CLL) is a disease of mature B cells, which rely on the host environment for progression. [5][6][7] Tumor-host interactions occur predominantly in protected niches in the lymph nodes (LNs) and in the bone marrow, known as proliferation centers. 8,9 Within these areas, CLL cells are in contact with a population of CD681 elements, resembling tumor-associated macrophages. [10][11][12][13] They may be also differentiated in vitro by coculturing peripheral blood monocytes with CLL cells. These so-called nurselike cells (NLCs) protect leukemic cells from apoptosis through multiple interactions regulated by soluble or cell-surface-anchored molecules. 14,15 Leukemic cells play an essential role in driving NLC differentiation, as inferred fr...