CD38 at the junction between prognostic marker and therapeutic target

Development of a reporter gene method to measure the bioactivity of anti-CD38 × CD3 bispecific antibody

Background

A T cell-redirecting bispecific antibody (bsAb) consisting of a tumor-binding unit and a T cell-binding unit is a large group of antibody-based biologics against death-causing cancer diseases. The anti-CD38 × anti-CD3 bsAb (Y150) is potential for treating multiple myeloma (MM). When developing a cell-based reporter gene bioassay to assess the activities of Y150, it was found that the expression of CD38 on the human T lymphocyte cells (Jurkat) caused the nonspecific activation, which interfered with the specific T cells activation of mediated by the Y150 and CD38(+) tumor cells.

Methods

Here, we first knocked-out the CD38 expression on Jurkat T cell line by CRISPR-Cas9 technology, then developed a stable monoclonal CD38(−) Jurkat T cell line with an NFAT-RE driving luciferase expressing system. Further based on the CD38(−) Jurkat cell, we developed a reporter gene method to assess the bioactivity of the anti-CD38 × anti-CD3 bsAb.

Results

Knocking out CD38 expression abolished the nonspecific self-activation of the Jurkat cells. The selected stable monoclonal CD38(−) Jurkat T cell line assured the robustness of the report genes assay for the anti-CD38 × anti-CD3 bsAb. The relative potencies of the Y150 measured by the developed reporter gene assay were correlated with those by the flow-cytometry-based cell cytotoxicity assay and by the ELISA-based binding assay.

Conclusions

The developed reporter gene assay was mechanism of action-reflective for the bioactivity of anti-CD38 × anti-CD3 antibody, and suitable for the quality control for the bsAb product.

Mechanisms of Action of the New Antibodies in Use in Multiple Myeloma

Monoclonal antibodies (mAbs) directed against antigen-specific of multiple myeloma (MM) cells have Fc-dependent immune effector mechanisms, such as complement-dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC), and antibody-dependent cellular phagocytosis (ADCP), but the choice of the antigen is crucial for the development of effective immuno-therapy in MM. Recently new immunotherapeutic options in MM patients have been developed against different myeloma-related antigens as drug conjugate-antibody, bispecific T-cell engagers (BiTEs) and chimeric antigen receptor (CAR)-T cells. In this review, we will highlight the mechanism of action of immuno-therapy currently available in clinical practice to target CD38, SLAMF7, and BCMA, focusing on the biological role of the targets and on mechanisms of actions of the different immunotherapeutic approaches underlying their advantages and disadvantages with critical review of the literature data.

CD38 Multi-Functionality in Oral Squamous Cell Carcinoma: Prognostic Implications, Immune Balance, and Immune Checkpoint

Background

CD38 belongs to the ribosyl cyclase family and is expressed on various hematological cells and involved in immunosuppression and tumor promotion. Although targeting CD38 antibodies has been approved for treatment of multiple myeloma, the function of CD38 in solid tumor, oral squamous cell carcinoma (OSCC) etc., has not been investigated.

Methods

This retrospective study included 92 OSCC samples and analyzed the spatial distribution of CD38 by immunohistochemistry (IHC). The values of diagnosis and prognosis of CD38 were evaluated. Additionally, 53 OSCC preoperative peripheral blood samples were used to be analyzed by flow cytometry. Tumor Immune Estimation Resource (TIMER) and cBioPortal databases were used to study CD38 level in various tumors and its correlation with tumor immune microenvironment in head and neck squamous cell carcinoma (HNSCC).

Results

CD38 ubiquitously presented in tumor cells (TCs), fibroblast-like cells (FLCs), and tumor-infiltrating lymphocytes (TILs). Patients with highly expressed CD38 in TCs (CD38^TCs) had higher TNM stage and risk of lymph node metastasis. Upregulation of CD38 in FLCs (CD38^FLCs) was significantly associated with poor WPOI. Escalated CD38 in TILs (CD38^TILs) led to higher Ki-67 level of tumor cells. Moreover, patients with enhanced CD38^TCs were susceptible to postoperative metastasis occurrence, and those with highly expressed CD38^TILs independently predicted shorter overall and disease-free survival. Strikingly, patients with highly expressed CD38^TILs, but not CD38^TCs and CD38^FLCs, had significantly lower CD3⁺CD4⁺ T cells and higher ratio of CD3^-CD16⁺CD56⁺NK cells. The imbalance of immune system is attributed to dysregulated immune checkpoint molecules (VISTA, PD-1, LAG-3, CTLA-4, TIGIT, GITR) as well as particular immune cell subsets, which were positively correlated with CD38 expression in HNSCC.

Conclusion

CD38 is a poor prognostic biomarker for OSCC patients and plays a vital role in governing immune microenvironment and circulating lymphocyte homeostasis. Co-expression between CD38 and immune checkpoint molecules provides new insight into immune checkpoint therapy.

Bispecific T cell engagers: an emerging therapy for management of hematologic malignancies

Harnessing the power of immune cells, especially T cells, to enhance anti-tumor activities has become a promising strategy in clinical management of hematologic malignancies. The emerging bispecific antibodies (BsAbs), which recruit T cells to tumor cells, exemplified by bispecific T cell engagers (BiTEs), have facilitated the development of tumor immunotherapy. Here we discussed the advances and challenges in BiTE therapy developed for the treatment of hematologic malignancies. Blinatumomab, the first BiTE approved for the treatment of acute lymphocytic leukemia (ALL), is appreciated for its high efficacy and safety. Recent studies have focused on improving the efficacy of BiTEs by optimizing treatment regimens and refining the molecular structures of BiTEs. A considerable number of bispecific T cell-recruiting antibodies which are potentially effective in hematologic malignancies have been derived from BiTEs. The elucidation of mechanisms of BiTE action and neonatal techniques used for the construction of BsAbs can improve the treatment of hematological malignancies. This review summarized the features of bispecific T cell-recruiting antibodies for the treatment of hematologic malignancies with special focus on preclinical experiments and clinical studies.

CD31+, CD38+, CD44+, and CD103+ lymphocytes in peripheral blood, bronchoalveolar lavage fluid and lung biopsy tissue in sarcoid patients and controls

Background

The mechanisms driving the transition from inflammation to fibrosis in sarcoidosis patients are poorly understood; prognostic features are lacking. Immune cell profiling may provide insights into pathogenesis and prognostic factors of the disease. This study aimed to establish associations in simultaneous of lymphocyte subset profiles in the blood, bronchoalveolar lavage fluid (BALF), and lung biopsy tissue in the patients with newly diagnosed sarcoidosis.

Methods

A total of 71 sarcoid patients (SPs) and 20 healthy controls (HCs) were enrolled into the study. CD31, CD38, CD44, CD103 positive T lymphocytes in blood and BALF were analysed. Additionally, the densities of CD4, CD8, CD38, CD44, CD103 positive cells in lung tissue biopsies were estimated by digital image analysis.

Results

Main findings: (I) increase of percentage of CD3⁺CD4⁺CD38⁺ in BALF and blood, and increase of percentage of CD3⁺CD4⁺CD44⁺ in BALF in Löfgren syndrome patients comparing with patients without Löfgren syndrome, (II) increase of percentage of CD3⁺CD4⁺103⁺ in BALF and in blood in patients without Löfgren syndrome (comparing with Löfgren syndrome patients) and increase of percentage of CD3⁺CD4⁺103⁺ in BALF and in blood in more advanced sarcoidosis stage. (III) Increasing percentage of BALF CD3⁺CD4⁺CD31⁺ in sarcoidosis patients when comparing with controls independently of presence of Löfgren syndrome, smoking status or stage of sarcoidosis. Several significant correlations were found.

Conclusions

Lymphocyte subpopulations in blood, BALF, and lung tissue were substantially different in SPs at the time of diagnosis compared to HCs. CD3⁺CD4⁺CD31⁺ in BALF might be a potential supporting marker for the diagnosis of sarcoidosis. CD3⁺CD4⁺CD38⁺ in BALF and blood and CD3⁺CD4⁺CD44⁺ in BALF may be markers of the acute immune response in sarcoidosis patients. CD4⁺CD103⁺ T-cells in BALF and in blood are markers of the persistent immune response in sarcoidosis patients and are potential prognostic features of the chronic course of this disease.

Bispecific, T-Cell-Recruiting Antibodies in B-Cell Malignancies

Bispecific antibodies (BsAbs) are designed to recognize and bind to two different antigens or epitopes. In the last few decades, BsAbs have been developed within the context of cancer therapies and in particular for the treatment of hematologic B-cell malignancies. To date, more than one hundred different BsAb formats exist, including bispecific T-cell engagers (BiTEs), and new constructs are constantly emerging. Advances in protein engineering have enabled the creation of BsAbs with specific mechanisms of action and clinical applications. Moreover, a better understanding of resistance and evasion mechanisms, as well as advances in the protein engineering and in immunology, will help generating a greater variety of BsAbs to treat various cancer types. This review focuses on T-cell-engaging BsAbs and more precisely on the various BsAb formats currently being studied in the context of B-cell malignancies, on ongoing clinical trials and on the clinical concerns to be taken into account in the development of new BsAbs.

Targeting CD38-Expressing Multiple Myeloma and Burkitt Lymphoma Cells In Vitro with Nanobody-Based Chimeric Antigen Receptors (Nb-CARs)

The NAD-hydrolyzing ecto-enzyme CD38 is overexpressed by multiple myeloma and other hematological malignancies. We recently generated CD38-specific nanobodies, single immunoglobulin variable domains derived from heavy-chain antibodies naturally occurring in llamas. Nanobodies exhibit high solubility and stability, allowing easy reformatting into recombinant fusion proteins. Here we explore the utility of CD38-specific nanobodies as ligands for nanobody-based chimeric antigen receptors (Nb-CARs). We cloned retroviral expression vectors for CD38-specific Nb-CARs. The human natural killer cell line NK-92 was transduced to stably express these Nb-CARs. As target cells we used CD38-expressing as well as CRISPR/Cas9-generated CD38-deficient tumor cell lines (CA-46, LP-1, and Daudi) transduced with firefly luciferase. With these effector and target cells we established luminescence and flow-cytometry CAR-dependent cellular cytotoxicity assays (CARDCCs). Finally, the cytotoxic efficacy of Nb-CAR NK-92 cells was tested on primary patient-derived CD38-expressing multiple myeloma cells. NK-92 cells expressing CD38-specific Nb-CARs specifically lysed CD38-expressing but not CD38-deficient tumor cell lines. Moreover, the Nb-CAR-NK cells effectively depleted CD38-expressing multiple myeloma cells in primary human bone marrow samples. Our results demonstrate efficacy of Nb-CARs in vitro. The potential clinical efficacy of Nb-CARs in vivo remains to be evaluated.

212Pb α-Radioimmunotherapy Targeting CD38 in Multiple Myeloma: A Preclinical Study

Multiple myeloma (MM) is a plasma cell cancer and represents the second most frequent hematologic malignancy. Despite new treatments and protocols, including high-dose chemotherapy associated with autologous stem cell transplantation, the prognosis of MM patients is still poor. α-radioimmunotherapy (α-RIT) represents an attractive treatment strategy because of the high-linear-energy transfer and short pathlength of α-radiation in tissues, resulting in high tumor cell killing and low toxicity to surrounding tissues. In this study, we investigated the potential of α-RIT with ²¹²Pb-daratumumab (anti-hCD38), in both in vitro and in vivo models, as well as an antimouse CD38 antibody using in vivo models. Methods: Inhibition of cell proliferation after incubation of the RPMI8226 cell line with an increasing activity (0.185-3.7 kBq/mL) of ²¹²Pb-isotypic control or ²¹²Pb-daratumumab was evaluated. Biodistribution was performed in vivo by SPECT/CT imaging and after death. Dose-range-finding and acute toxicity studies were conducted. Because daratumumab does not bind the murine CD38, biodistribution and dose-range finding were also determined using an antimurine CD38 antibody. To evaluate the in vivo efficacy of ²¹²Pb-daratumumab, mice were engrafted subcutaneously with 5 × 10⁶ RPMI8226 cells. Mice were treated 13 d after engraftment with an intravenous injection of ²¹²Pb-daratumumab or control solution. Therapeutic efficacy was monitored by tumor volume measurements and overall survival. Results: Significant inhibition of proliferation of the human myeloma RPMI8226 cell line was observed after 3 d of incubation with ²¹²Pb-daratumumab, compared with ²¹²Pb-isotypic control or cold antibodies. Biodistribution studies showed a specific tumoral accumulation of daratumumab. No toxicity was observed with ²¹²Pb-daratumumab up to 370 kBq because of lack of cross-reactivity. Nevertheless, acute toxicity experiments with ²¹²Pb-anti-mCD38 established a toxic activity of 277.5 kBq. To remain within realistically safe treatment activities for efficacy studies, mice were treated with 185 kBq or 277.5 kBq of ²¹²Pb-daratumumab. Marked tumor growth inhibition compared with controls was observed, with a median survival of 55 d for 277.5 kBq of ²¹²Pb-daratumumab instead of 11 d for phosphate-buffered saline. Conclusion: These results showed ²¹²Pb-daratumumab to have efficacy in xenografted mice, with significant tumor regression and increased survival. This study highlights the potency of α-RIT in MM treatment.

CD38 Expression by Myeloma Cells and Its Role in the Context of Bone Marrow Microenvironment: Modulation by Therapeutic Agents

In the last decades CD38 has emerged as an attractive target for multiple myeloma (MM). CD38 is a novel multifunctional glycoprotein that acts as a receptor, adhesion molecule interacting with CD31 and as an ectoenzyme. As an ectoenzyme, CD38 functions as a metabolic sensor catalyzing the extracellular conversion of NAD+ to the immunosuppressive factor adenosine (ADO). Other ectoenzymes, CD73 and CD203a, together with CD38, are also involved in the alternative axis of extracellular production of ADO, bypassing the canonical pathway mediated by CD39. CD38 is ubiquitously expressed in the bone marrow microenvironment; however, only MM cells display a very high surface density, which lead to the development of several anti-CD38 monoclonal antibodies (mAbs). The efficacy of anti-CD38 mAbs depends from the presence of CD38 on the surface of MM and immune-microenvironment cells. Interestingly, it has been reported that several drugs like lenalidomide, panobinostat, the all-trans retinoic acid and the DNA methyltransferase inhibitors may increase the expression of CD38. Hence, the possibility to modulate CD38 by increasing its expression on MM cells is the pre-requisite to potentiate the clinical efficacy of the anti-CD38 mAbs and to design clinical trials with the combination of anti-CD38 mAbs and these drugs.

Comparison of the effects of bacteriophage-derived dsRNA and poly(I:C) on ex vivo cultivated peripheral blood mononuclear cells

Double-stranded RNA (dsRNA), regardless of the origin and nucleotide sequence, exhibits multiple biological activities, including the establishment of an antiviral state and modulation of the immune response. Both involve the stimulation of innate immunity primarily via the release of pro-inflammatory cytokines, which in turn shapes the adaptive immune response. In this study, we compared the immune response triggered by two different dsRNAs: 1) a well-known synthetic dsRNA-poly (I:C); and 2) bacteriophage-derived dsRNA (bf-dsRNA) that is a replicative form of ssRNA bacteriophage f2. Human peripheral blood mononuclear cells (PBMCs) from 61 heathy volunteers were stimulated ex vivo with both dsRNAs. Subsequently, activation markers on the main lymphocyte subpopulations were analysed by flow cytometry and the production of 29 different cytokines and chemokines was measured by Luminex xMAP technology. The effect of bf-dsRNA on ex vivo cultivated PBMCs is similar to that induced by poly(I:C), albeit with subtle dissimilarities. Both treatments increased expression of the lymphocyte CD38 marker and intracellular IFN-γ in CD8⁺ T and natural killer (NK) cells, as well as the CD95 marker on the main lymphocyte subpopulations. Poly(I:C) was a stronger inducer of IL-6, IL-1β, and CCL4, whereas bf-dsRNA induced higher levels of IFN-α2, CXCL10, and CCL17. These differences might contribute to a distinct clinical manifestation when used as vaccine adjuvants, and bf-dsRNA may have more profound activity against several types of bacteria.

The Mechanism of Action of the Anti-CD38 Monoclonal Antibody Isatuximab in Multiple Myeloma

PURPOSE

Knowledge about the mechanism of action (MoA) of monoclonal antibodies (mAb) is required to understand which patients with multiple myeloma (MM) benefit the most from a given mAb, alone or in combination therapy. Although there is considerable research about daratumumab, knowledge about other anti-CD38 mAbs remains scarce.

EXPERIMENTAL DESIGN

We performed a comprehensive analysis of the MoA of isatuximab.

RESULTS

Isatuximab induces internalization of CD38 but not its significant release from MM cell surface. In addition, we uncovered an association between levels of CD38 expression and different MoA: (i) Isatuximab was unable to induce direct apoptosis on MM cells with CD38 levels closer to those in patients with MM, (ii) isatuximab sensitized CD38^hi MM cells to bortezomib plus dexamethasone in the presence of stroma, (iii) antibody-dependent cellular cytotoxicity (ADCC) was triggered by CD38^lo and CD38^hi tumor plasma cells (PC), (iv) antibody-dependent cellular phagocytosis (ADCP) was triggered only by CD38^hi MM cells, whereas (v) complement-dependent cytotoxicity could be triggered in less than half of the patient samples (those with elevated levels of CD38). Furthermore, we showed that isatuximab depletes CD38^hi B-lymphocyte precursors and natural killer (NK) lymphocytes ex vivo-the latter through activation followed by exhaustion and eventually phagocytosis.

CONCLUSIONS

This study provides a framework to understand response determinants in patients treated with isatuximab based on the number of MoA triggered by CD38 levels of expression, and for the design of effective combinations aimed at capitalizing disrupted tumor-stroma cell protection, augmenting NK lymphocyte-mediated ADCC, or facilitating ADCP in CD38^lo MM patients.See related commentary by Malavasi and Faini, p. 2946.

Design of new CD38 inhibitors based on CoMFA modelling and molecular docking analysis of 4‑amino-8-quinoline carboxamides and 2,4-diamino-8-quinazoline carboxamides

In this study, based on molecular docking analysis and comparative molecular field analysis (CoMFA) modelling of a series of 71 CD38 inhibitors including 4‑amino-8-quinoline carboxamides and 2,4-diamino-8-quinazoline carboxamides, new CD38 inhibitors were designed. The interactions of the molecules with the greatest and the lowest activities with the nicotinamide mononucleotide (NMN) binding site were investigated by molecular docking analysis. A CoMFA model with four partial least squares regression (PLSR) components was developed to predict the CD38 inhibitory activity of the molecules. The r² values for the training and test sets were 0.89 and 0.82, respectively. The Q² values for leave-one-out cross-validation (LOO-CV) and leave-many-out cross-validation (LMO-CV) tests on the training set were 0.65 and 0.64, respectively. The CoMFA model was validated by calculating several statistical parameters. CoMFA contour maps were interpreted, and structural features that influence the CD38 inhibitory activity of molecules were determined. Finally, seven new CD38 inhibitors with greater activity with respect to the greatest active molecules were designed.

Inflammatory cell expression of Toll-like receptor-2 (TLR2) within refractory periapical granuloma

Background: Toll-like receptor-2 (TLR2) is highly important within the immune system. Characterization of the expression of TLR2 within inflammatory cells in periapical lesions could help in diagnosis and management of refractory cases. The aim of the study is identification of Toll-like receptor (TLR2) through immunohistochemical and immunofluroscence expression in inflammatory cells within refractory periapical granuloma cases. Methods: Eight cases of refractory periapical granuloma were selected out of 772 cases. Histological examination and immunohistochemical staining with polyclonal rabbit antihuman TLR2, monoclonal mouse antihuman CD38, CD68 and CD83 primary antibodies, as well as immunofluorescence staining with goat anti-rabbit TLR2, donkey anti-mouse CD38, CD68 and CD83 primary antibodies was conducted. Positive controls, negative controls and experimental sections with no primary antibody were included in the study. Qualitative analysis and double immunofluorescence technique was used to characterize the TLR + cells. Results: In periapical granuloma, lymphocytes (CD38 cells) expressed the most amount of TLR reactivity followed by macrophages (CD68 cells), and odontogenic epithelial cells. Neutrophils, red blood cells (RBCs) and collagen ground substance were negative to TLR2.  Conclusion: TLR2 was highly expressed by lymphocytes and plasma cells indicative of their major role in the inflammatory process and antigen recognition in refractory periapical granuloma. Dendritic cells expressing TLR2 were low in number suggesting a minor role in sustaining these lesions.

Current developments in immunotherapy in the treatment of multiple myeloma

Multiple myeloma (MM) is the second most common hematologic malignancy and represents approximately 10% of all hematological neoplasms. Standard therapy consists of induction therapy followed by high-dose chemotherapy and autologous stem cell transplantation (ASCT) or, if ASCT cannot be performed, standard doublet, triplet, or quadruplet, novel agent-containing induction treatment until progression. Although MM is still regarded as mostly incurable by current standards, the development of several novel compounds, combination therapies, and immunotherapy approaches has raised great hopes about transforming MM into an indolent, chronic disease and possibly achieving a cure for individual patients. Several new inhibitory and immunological agents have been approved or are under intensive investigation and may lead to new therapeutic options for patients with relapsed/refractory MM, for patients ineligible for ASCT, and for patients after ASCT. Especially in the field of immunotherapy, including monoclonal antibodies, checkpoint inhibition, and chimeric antigen receptor T cells, current advances are rapid and highly promising. This review aims to summarize the newest and most promising immunotherapeutic agents for MM, their clinical efficacy, their adverse event (AE) profiles, and the ways in which these AEs can best be overcome or avoided. Cancer 2018;124:2075-85. © 2018 American Cancer Society.

Prognostic value of antigen expression in multiple myeloma: a PETHEMA/GEM study on 1265 patients enrolled in four consecutive clinical trials

Persistence of minimal residual disease (MRD) after treatment for myeloma predicts inferior outcomes, but within MRD-positive patients there is great heterogeneity with both early and very late relapses. Among different MRD techniques, flow cytometry provides additional information about antigen expression on tumor cells, which could potentially contribute to stratify MRD-positive patients. We investigated the prognostic value of those antigens required to monitor MRD in 1265 newly diagnosed patients enrolled in the GEM2000, GEM2005MENOS65, GEM2005MAS65 and GEM2010MAS65 protocols. Overall, CD19^pos, CD27^neg, CD38^lo, CD45^pos, CD81^pos, CD117^neg and CD138^lo expression predicted inferior outcomes. Through principal component analysis, we found that simultaneous CD38^lowCD81^posCD117^neg expression emerged as the most powerful combination with independent prognostic value for progression-free survival (HR:1.69; P=0.002). This unique phenotypic profile retained prognostic value among MRD-positive patients. We then used next-generation flow to determine antigen stability throughout the course of the disease, and found that the expression of antigens required to monitor MRD is mostly stable from diagnosis to MRD stages, except for CD81 whose expression progressively increased from baseline to chemoresistant tumor cells (14 vs 28%). Altogether, we showed that the phenotypic profile of tumor cells provides additional prognostic information, and could be used to further predict risk of relapse among MRD-positive patients.

Nanobodies effectively modulate the enzymatic activity of CD38 and allow specific imaging of CD38+ tumors in mouse models in vivo

The cell surface ecto-enzyme CD38 is a promising target antigen for the treatment of hematological malignancies, as illustrated by the recent approval of daratumumab for the treatment of multiple myeloma. Our aim was to evaluate the potential of CD38-specific nanobodies as novel diagnostics for hematological malignancies. We successfully identified 22 CD38-specific nanobody families using phage display technology from immunized llamas. Crossblockade analyses and in-tandem epitope binning revealed that the nanobodies recognize three different non-overlapping epitopes, with four nanobody families binding complementary to daratumumab. Three nanobody families inhibit the enzymatic activity of CD38 in vitro, while two others were found to act as enhancers. In vivo, fluorochrome-conjugated CD38 nanobodies efficiently reach CD38 expressing tumors in a rodent model within 2 hours after intravenous injection, thereby allowing for convenient same day in vivo tumor imaging. These nanobodies represent highly specific tools for modulating the enzymatic activity of CD38 and for diagnostic monitoring CD38-expressing tumors.

Protein signatures of molecular pathways in non-small cell lung carcinoma (NSCLC): comparison of glycoproteomics and global proteomics

Background

Non-small cell lung carcinoma (NSCLC) remains the leading cause of cancer deaths in the United States. More than half of NSCLC patients have clinical presentations with locally advanced or metastatic disease at the time of diagnosis. The large-scale genomic analysis of NSCLC has demonstrated that molecular alterations are substantially different between adenocarcinoma (ADC) and squamous cell carcinoma (SqCC). However, a comprehensive analysis of proteins and glycoproteins in different subtypes of NSCLC using advanced proteomic approaches has not yet been conducted.

Methods

We applied mass spectrometry (MS) technology featuring proteomics and glycoproteomics to analyze six primary lung SqCCs and eleven ADCs, and we compared the expression level of proteins and glycoproteins in tumors using quantitative proteomics. Glycoproteins were analyzed by enrichment using a chemoenzymatic method, solid-phase extraction of glycopeptides, and quantified by iTRAQ-LC–MS/MS. Protein quantitation was further annotated via Ingenuity Pathway Analysis.

Results

Over 6000 global proteins and 480 glycoproteins were quantitatively identified in both SqCC and ADC. ADC proteins (8337) consisted of enzymes (22.11%), kinases (5.11%), transcription factors (6.85%), transporters (6.79%), and peptidases (3.30%). SqCC proteins (6967) had a very similar distribution. The identified glycoproteins, in order of relative abundance, included membrane (42%) and extracellular matrix (>33%) glycoproteins. Oncogene-coded proteins (82) increased 1.5-fold among 1047 oncogenes identified in ADC, while 124 proteins from SqCC were up-regulated in tumor tissues among a total of 827 proteins. We identified 680 and 563 tumor suppressor genes from ADC and SqCC, respectively.

Conclusion

Our systematic analysis of proteins and glycoproteins demonstrates changes of protein and glycoprotein relative abundance in SqCC (TP53, U2AF1, and RXR) and in ADC (SMARCA4, NOTCH1, PTEN, and MST1). Among them, eleven glycoproteins were upregulated in both ADC and SqCC. Two glycoproteins (ELANE and IGFBP3) were only increased in SqCC, and six glycoproteins (ACAN, LAMC2, THBS1, LTBP1, PSAP and COL1A2) were increased in ADC. Ingenuity Pathway Analysis (IPA) showed that several crucial pathways were activated in SqCC and ADC tumor tissues.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-017-9166-9) contains supplementary material, which is available to authorized users.

Reduced Plasmodium Parasite Burden Associates with CD38+ CD4+ T Cells Displaying Cytolytic Potential and Impaired IFN-γ Production

Using a unique resource of samples from a controlled human malaria infection (CHMI) study, we identified a novel population of CD4+ T cells whose frequency in the peripheral blood was inversely correlated with parasite burden following P. falciparum infection. These CD4+ T cells expressed the multifunctional ectoenzyme CD38 and had unique features that distinguished them from other CD4+ T cells. Specifically, their phenotype was associated with proliferation, activation and cytotoxic potential as well as significantly impaired production of IFN-γ and other cytokines and reduced basal levels of activated STAT1. A CD38+ CD4+ T cell population with similar features was identified in healthy uninfected individuals, at lower frequency. CD38+ CD4+ T cells could be generated in vitro from CD38- CD4+ T cells after antigenic or mitogenic stimulation. This is the first report of a population of CD38+ CD4+ T cells with a cytotoxic phenotype and markedly impaired IFN-γ capacity in humans. The expansion of this CD38+ CD4+ T population following infection and its significant association with reduced blood-stage parasite burden is consistent with an important functional role for these cells in protective immunity to malaria in humans. Their ubiquitous presence in humans suggests that they may have a broad role in host-pathogen defense.

TRIAL REGISTRATION

ClinicalTrials.gov clinical trial numbers ACTRN12612000814875, ACTRN12613000565741 and ACTRN12613001040752.

Key Molecular Drivers of Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is an adult neoplastic disease of B cells characterized by variable clinical outcomes. Although some patients have an aggressive form of the disease and often encounter treatment failure and short survival, others have more stable disease with long-term survival and little or no need for theraphy. In the past decade, significant advances have been made in our understanding of the molecular drivers that affect the natural pathology of CLL. The present review describes what is known about these key molecules in the context of their role in tumor pathogenicity, prognosis, and therapy.

Immuno-targeting the multifunctional CD38 using nanobody

CD38, as a cell surface antigen is highly expressed in several hematologic malignancies including multiple myeloma (MM) and has been proven to be a good target for immunotherapy of the disease. CD38 is also a signaling enzyme responsible for the metabolism of two novel calcium messenger molecules. To be able to target this multifunctional protein, we generated a series of nanobodies against CD38 with high affinities. Crystal structures of the complexes of CD38 with the nanobodies were solved, identifying three separate epitopes on the carboxyl domain. Chromobodies, engineered by tagging the nanobody with fluorescence proteins, provide fast, simple and versatile tools for quantifying CD38 expression. Results confirmed that CD38 was highly expressed in malignant MM cells compared with normal white blood cells. The immunotoxin constructed by splicing the nanobody with a bacterial toxin, PE38 shows highly selective cytotoxicity against patient-derived MM cells as well as the cell lines, with half maximal effective concentration reaching as low as 10⁻¹¹ molar. The effectiveness of the immunotoxin can be further increased by stimulating CD38 expression using retinoid acid. These results set the stage for the development of clinical therapeutics as well as diagnostic screening for myeloma.

Is Oxytocin Application for Autism Spectrum Disorder Evidence-Based?

Autism spectrum disorder (ASD) is characterized by persistent deficits within two core symptom domains: social communication and restricted, repetitive behaviors. Although numerous studies have reported psychopharmacological treatment outcomes for the core symptom domains of ASD, there are not enough studies on fundamental treatments based on the etiological pathology of ASD. Studies on candidate medications related to the pathogenesis of ASD, such as naltrexone and secretin, were conducted, but the results were inconclusive. Oxytocin has been identified as having an important role in maternal behavior and attachment, and it has been recognized as a key factor in the social developmental deficit seen in ASD. Genetic studies have also identified associations between ASD and the oxytocin pathway. As ASD has its onset in infancy, parents are willing to try even experimental or unapproved treatments in an effort to avoid missing the critical period for diagnosis and treatment, which can place their child in an irreversible state. While therapeutic application of oxytocin for ASD is in its early stages, we have concluded that oxytocin would be a promising therapeutic substance via a thorough literature review focusing on the following: the relationship between oxytocin and sociality; single nucleotide polymorphisms as a biological marker of ASD; and validity verification of oxytocin treatment in humans. We also reviewed materials related to the mechanism of oxytocin action that may support its potential application in treating ASD.

CD38 Monoclonal Antibody Therapies for Multiple Myeloma

The goal of this review is to provide historical, recent preclinical, and current clinical summaries of efforts to understand the CD38 molecule and to develop monoclonal antibodies that target it. We focus particularly on efforts involving multiple myeloma, a malignancy of terminally differentiated B cells that remains incurable despite many advances. An era of anti-CD38 monoclonal antibody therapy for myeloma is approaching, one that, we hope, will enable patients to live longer and better lives.

Comparative Analysis of Pharmacophore Features and Quantitative Structure-Activity Relationships for CD38 Covalent and Non-covalent Inhibitors

In the past decade, the discovery, synthesis, and evaluation for hundreds of CD38 covalent and non-covalent inhibitors has been reported sequentially by our group and partners; however, a systematic structure-based guidance is still lacking for rational design of CD38 inhibitor. Here, we carried out a comparative analysis of pharmacophore features and quantitative structure-activity relationships for CD38 inhibitors. The results uncover that the essential interactions between key residues and covalent/non-covalent CD38 inhibitors include (i) hydrogen bond and hydrophobic interactions with residues Glu226 and Trp125, (ii) electrostatic or hydrogen bond interaction with the positively charged residue Arg127 region, and (iii) the hydrophobic interaction with residue Trp189. For covalent inhibitors, besides the covalent effect with residue Glu226, the electrostatic interaction with residue Arg127 is also necessary, while another hydrogen/non-bonded interaction with residues Trp125 and Trp189 can also be detected. By means of the SYBYL multifit alignment function, the best CoMFA and CoMSIA with CD38 covalent inhibitors presented cross-validated correlation coefficient values (q(2)) of 0.564 and 0.571, and non-cross-validated values (r(2)) of 0.967 and 0.971, respectively. The CD38 non-covalent inhibitors can be classified into five groups according to their chemical scaffolds, and the residues Glu226, Trp189, and Trp125 are indispensable for those non-covalent inhibitors binding to CD38, while the residues Ser126, Arg127, Asp155, Thr221, and Phe222 are also important. The best CoMFA and CoMSIA with the F12 analogues presented cross-validated correlation coefficient values (q(2)) of 0.469 and 0.454, and non-cross-validated values (r(2)) of 0.814 and 0.819, respectively.

CD38 is a putative functional marker for side population cells in human nasopharyngeal carcinoma cell lines

Cancer stem cells (CSCs) are thought to be responsible for cancer progression and therapeutic resistance but identification of this subpopulation requires selective markers. Fortunately, side population (SP) cells analysis brings a novel method to CSCs study. In this study, we identified SP cells, which are demonstrated rich in CSCs, in four nasopharyngeal carcinoma (NPC) cell lines. We investigated SP cells from HK-1 NPC cell line and showed CSCs characteristics in this subpopulation. SP cells displayed greater proliferation and invasion and expressed high levels of CSCs markers than NSP cells. Furthermore, our microRNA microarray analysis of SP versus NSP cells revealed that CD38-related miRNAs were down-regulated in SP cell, but the mRNA and protein level of CD38 were highly expressed in SP cells. We further searched for molecules interacting with CD38 and identified ZAP70, which was also well expressed in SP cells at both mRNA and protein levels. Our results uncover a CD38 pathway that may regulate the proliferation and migration of SP cells from HK-1 NPC cell line.

Electroosmotic perfusion of tissue: sampling the extracellular space and quantitative assessment of membrane-bound enzyme activity in organotypic hippocampal slice cultures

This review covers recent advances in sampling fluid from the extracellular space of brain tissue by electroosmosis (EO). Two techniques, EO sampling with a single fused-silica capillary and EO push-pull perfusion, have been developed. These tools were used to investigate the function of membrane-bound enzymes with outward-facing active sites, or ectoenzymes, in modulating the activity of the neuropeptides leu-enkephalin and galanin in organotypic-hippocampal-slice cultures (OHSCs). In addition, the approach was used to determine the endogenous concentration of a thiol, cysteamine, in OHSCs. We have also investigated the degradation of coenzyme A in the extracellular space. The approach provides information on ectoenzyme activity, including Michaelis constants, in tissue, which, as far as we are aware, has not been done before. On the basis of computational evidence, EO push-pull perfusion can distinguish ectoenzyme activity with a ~100 μm spatial resolution, which is important for studies of enzyme kinetics in adjacent regions of the rat hippocampus.

Possible role of hemichannels in cancer

In humans, connexins (Cxs) and pannexins (Panxs) are the building blocks of hemichannels. These proteins are frequently altered in neoplastic cells and have traditionally been considered as tumor suppressors. Alteration of Cxs and Panxs in cancer cells can be due to genetic, epigenetic and post-transcriptional/post-translational events. Activated hemichannels mediate the diffusional membrane transport of ions and small signaling molecules. In the last decade hemichannels have been shown to participate in diverse cell processes including the modulation of cell proliferation and survival. However, their possible role in tumor growth and expansion remains largely unexplored. Herein, we hypothesize about the possible role of hemichannels in carcinogenesis and tumor progression. To support this theory, we summarize the evidence regarding the involvement of hemichannels in cell proliferation and migration, as well as their possible role in the anti-tumor immune responses. In addition, we discuss the evidence linking hemichannels with cancer in diverse models and comment on the current technical limitations for their study.

Clinical significance of serum ADP-ribosylation and NAD glycohydrolase activity in patients with colorectal cancer

The objective of this study was to evaluate the clinical significance of serum ADP-ribosylation and NAD glycohydrolase activity in patients with colorectal cancer (CRC). A total of 108 patients with CRC who underwent curative surgery and 20 healthy volunteers were enrolled in this study. ADP-ribosylation and NAD glycohydrolase activity levels were determined. The association of ADP-ribosylation and NAD glycohydrolase with clinical and laboratory factors and their impact on overall survival (OS) and disease free survival (DFS) were shown. The preoperative ADP-ribosylation and NAD glycohydrolase activity levels were significantly higher in patients with CRC than in the control group (p<0.001). ADP-ribosylation and NAD glycohydrolase activity levels were correlated with tumor stage (p=0.05, p=0.001), stage of disease (p<0.001, p<0.001), serum CEA level (p<0.001, p<0.001), and site of lesion (p<0.001, p<0.001), respectively. Patients with high ADP-ribosylation had significantly unfavorable OS and DFS compared with those with lower levels (p<0.001, p<0.001), respectively. Moreover, the patients with high NAD glycohydrolase activity showed significantly worse OS and DFS rates, similar to ADP-ribosylation. Serum levels of ADP-ribosylation and NAD glycohydrolase activity correlate well with tumor stage, stage of disease, serum CEA level, and site of lesion. In conclusion, elevated levels of preoperative ADP-ribosylation and NAD glycohydrolase levels in serum are associated with poor prognosis in patients with CRC.

A preclinical model of CD38-pretargeted radioimmunotherapy for plasma cell malignancies

The vast majority of patients with plasma cell neoplasms die of progressive disease despite high response rates to novel agents. Malignant plasma cells are very radiosensitive, but the potential role of radioimmunotherapy (RIT) in the management of plasmacytomas and multiple myeloma has undergone only limited evaluation. Furthermore, CD38 has not been explored as a RIT target despite its uniform high expression on malignant plasma cells. In this report, both conventional RIT (directly radiolabeled antibody) and streptavidin-biotin pretargeted RIT (PRIT) directed against the CD38 antigen were assessed as approaches to deliver radiation doses sufficient for multiple myeloma cell eradication. PRIT demonstrated biodistributions that were markedly superior to conventional RIT. Tumor-to-blood ratios as high as 638:1 were seen 24 hours after PRIT, whereas ratios never exceeded 1:1 with conventional RIT. (90)Yttrium absorbed dose estimates demonstrated excellent target-to-normal organ ratios (6:1 for the kidney, lung, liver; 10:1 for the whole body). Objective remissions were observed within 7 days in 100% of the mice treated with doses ranging from 800 to 1,200 μCi of anti-CD38 pretargeted (90)Y-DOTA-biotin, including 100% complete remissions (no detectable tumor in treated mice compared with tumors that were 2,982% ± 2,834% of initial tumor volume in control animals) by day 23. Furthermore, 100% of animals bearing NCI-H929 multiple myeloma tumor xenografts treated with 800 μCi of anti-CD38 pretargeted (90)Y-DOTA-biotin achieved long-term myeloma-free survival (>70 days) compared with none (0%) of the control animals.

Impairment of B-cell functions during HIV-1 infection

A variety of B-cell dysfunctions are manifested during HIV-1 infection, as reported early during the HIV-1 epidemic. It is not unusual that the pathogenic mechanisms presented to elucidate impairment of B-cell responses during HIV-1 infection focus on the impact of reduced T-cell numbers and functions, and lack of germinal center formation in lymphoid tissues. To our understanding, however, perturbation of B-cell phenotype and function during HIV-1 infection may begin at several different B-cell developmental stages. These impairments can be mediated by intrinsic B-cell defects as well as by the lack of proper T-cell help. In this review, we will highlight some of the pathways and molecular interactions leading to B-cell impairment prior to germinal center formation and B-cell activation mediated through the B-cell receptor in response to HIV-1 antigens. Recent studies indicate a regulatory role for B cells on T-cell biology and immune responses. We will discuss some of these novel findings and how these regulatory mechanisms could potentially be affected by the intrinsic defects of B cells taking place during HIV-1 infection.

Purification of NAD+ glycohydrolase from human serum

In the present study, NAD⁺ glycohydrolase was purified from serum samples collected from healthy individuals using ammonium sulfate fractionation, Affi-Gel blue (Cibacron Blue F3GA) affinity chromatography, Sephadex G-100 column chromatography and isoelectric focusing. The final step was followed by a second Sephadex G-100 column chromatography assay in order to remove the ampholytes from the isoelectric focusing step. In terms of enhancement of specific activity, the NAD⁺ glycohydrolase protein was purified ∼480-fold, with a yield of 1% compared with the initial serum fraction. The purified fraction appeared to be homogeneous, with a molecular weight of 39 kDa, as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, and also corresponded to the soluble (monomeric) form of surface antigen CD38.

Increased CD38 expression in T cells and circulating anti-CD38 IgG autoantibodies differentially correlate with distinct cytokine profiles and disease activity in systemic lupus erythematosus patients

CD38 is a multifunctional protein possessing ADP-ribosyl cyclase activity responsible for both the synthesis and the degradation of several Ca(2+)-mobilizing second messengers. In mammals, CD38 also functions as a receptor. In this study CD38 expression in CD4(+), CD8(+), or CD25(+) T cells was significantly higher in systemic lupus erythematosus (SLE) patients than in Normal controls. Increased CD38 expression in SLE T cells correlated with plasma levels of Th2 (IL-4, IL-10, IL-13) and Th1 (IL-1β, IL-12, IFN-γ, TNF-α) cytokines, and was more prevalent in clinically active SLE patients than in Normal controls. In contrast, elevated anti-CD38 IgG autoantibodies were more frequent in clinically quiescent SLE patients (SLEDAI=0) than in Normal controls, and correlated with moderate increased plasma levels of IL-10 and IFN-γ. However, clinically active SLE patients were mainly discriminated from quiescent SLE patients by increased levels of IL-10 and anti-dsDNA antibodies, with odds ratios (ORs) of 3.7 and 4.8, respectively. Increased frequency of anti-CD38 autoantibodies showed an inverse relationship with clinical activity (OR=0.43), and in particular with the frequency of anti-dsDNA autoantibodies (OR=0.21). Increased cell death occurred in CD38(+) Jurkat T cells treated with anti-CD38(+) SLE plasmas, and not in these cells treated with anti-CD38(-) SLE plasmas, or Normal plasmas. This effect did not occur in CD38-negative Jurkat T cells, suggesting that it could be attributed to anti-CD38 autoantibodies. These results support the hypothesis that anti-CD38 IgG autoantibodies or their associated plasma factors may dampen immune activation by affecting the viability of CD38(+) effector T cells and may provide protection from certain clinical SLE features.

Targeting the microenvironment in chronic lymphocytic leukemia offers novel therapeutic options

Chronic lymphocytic leukemia (CLL) cells display features consistent with a defect in apoptosis and exhibit prolonged survival in vivo. Survival of these malignant cells is influenced by interactions with non-leukemic cells located in permissive niches in lymphoid organs. Leukemic cells subvert the normal architecture of the lymphoid organs, recruiting stromal cells, dendritic cells and T lymphocytes, all reported as playing active roles in the survival and proliferation of CLL. The same survival-promoting environment also rescues/protects leukemic cells from cytotoxic therapies, giving way to disease relapse. This review summarizes and discusses current knowledge about the intricate network of soluble and cell-bound signals regulating the life and death of CLL cells in different districts. At the same time, it seeks to hone in on which discrete molecular elements are best suited as targets for treating this still incurable disease.

Bone marrow stromal cells protect lymphoma B-cells from rituximab-induced apoptosis and targeting integrin α-4-β-1 (VLA-4) with natalizumab can overcome this resistance

Rituximab improves the outcome of patients with non-Hodgkin lymphoma, but does not completely eradicate residual B-cell populations in the microenvironment of the bone marrow and lymph nodes. Adhesion to stromal cells can protect B-cells from apoptosis induced by chemotherapy drugs [(cell adhesion-mediated drug resistance (CAM-DR)]. A similar mechanism of resistance to rituximab has not, to our knowledge, been described. We tested the hypothesis that the microenvironment protects malignant B-cells from rituximab-induced apoptosis, and that blocking these interactions with natalizumab, an antibody targeting VLA-4 (integrin alfa-4-beta-1/CD49d), can overcome this protection. VLA-4 is an adhesion molecule constitutively expressed on malignant B-cells and is important for pro-survival signalling in the bone marrow and lymph node microenvironment. The human bone marrow stromal cell line HS-5 was shown to strongly protect B-cell lymphoma cells from rituximab cytotoxicity, suggesting the existence of a stromal cell adhesion-mediated antibody resistance (CAM-AR) mechanism analogous to CAM-DR. Natalizumab decreased B-lymphocyte adherence to fibronectin by 75-95% and partially overcame stromal protection against rituximab and cytotoxic drugs. These pre-clinical findings suggest that the addition of stromal adhesion-disruptive drugs to rituximab-containing therapy could improve treatment efficacy.

CD38 expression as response of hematopoietic system to cancer

Erythrocyte and lymphocyte NAD(+) glycohydrolase levels were previously found to be elevated in cancer patients. These results were confirmed in an animal model. The administration of live Ehrlich ascites tumor cells to BALB/c mice led to increases in erythrocyte and lymphocyte NAD(+) glycohydrolase, along with tumor development. Serum samples, ascites fluid from mice with developed tumors, serum samples from cancer patients and Ehrlich cell supernatants had a similar stimulatory effect when administered to mice or when incubated with peripheric lymphocytes in culture. These increases were accompanied by the appearance of an anti-CD38 reactive band of 45 kDa in SDS-PAGE/Western blot analyses of erythrocyte ghost and lymphocyte membrane proteins. The results, supported by flow cytometry data, support previous clinical findings that an enhancement in CD38 expression occurs in the hematopoietic system during proliferative processes. Moreover, they suggest that CD38 expression is triggered at least in part by a certain cytokine(s) secreted by cancer cells. Finally, the results emphasize the prospective use of CD38 expression as a marker of tumor development and progression.

Flavonoids as inhibitors of human CD38

CD38 is a multifunctional enzyme which is ubiquitously distributed in mammalian tissues. It is involved in the conversion of NAD(P)(+) into cyclic ADP-ribose, NAADP(+) and ADP-ribose and the role of these metabolites in multiple Ca(2+) signaling pathways makes CD38 a novel potential pharmacological target. The dire paucity of CD38 inhibitors, however, renders the search for new molecular tools highly desirable. We report that human CD38 is inhibited at low micromolar concentrations by flavonoids such as luteolinidin, kuromanin and luteolin (IC(50) <10 μM). Docking studies provide some clues on the mode of interaction of these molecules with the active site of CD38.

Are retinoids potential therapeutic agents in disorders of social cognition including autism?

Increasing evidence suggests that the nonapeptide, oxytocin (OT), helps shape social and affiliative behaviors not only in lower mammals but also in humans. Recently, an essential mediator of brain OT release has been discovered, ADP-ribosyl cyclase and/or CD38. We have subsequently shown that polymorphisms across the CD38 gene are associated with autism spectrum disorders (ASD). Notably, CD38 expression in lymphoblastoid cells (LBC) is reduced in cell lines derived from ASD subjects compared to parental cell lines. Intriguingly, a correlation was observed between CD38 expression and measures of social function in ASD. Finally, we have shown that all-trans retinoic acid (ATRA), a known inducer of CD38 transcription, can rescue low CD38 expressing LBC lines derived from ASD subjects and restore normal levels of transcription of this ectoenzyme providing 'proof of principle' in a peripheral model that retinoids are potential therapeutic agents in ASD.

All-trans retinoic acid upregulates reduced CD38 transcription in lymphoblastoid cell lines from Autism spectrum disorder

Deficits in social behavior in mice lacking the CD38 gene have been attributed to impaired secretion of oxytocin. In humans, similar deficits in social behavior are associated with autistic spectrum disorder (ASD), for which genetic variants of CD38 have been pinpointed as provisional risk factors. We sought to explore, in an in vitro model, the feasibility of the theory that restoring the level of CD38 in ASD patients could be of potential clinical benefit. CD38 transcription is highly sensitive to several cytokines and vitamins. One of these, all-trans retinoic acid (ATRA), a known inducer of CD38, was added during cell culture and tested on a large sample of N = 120 lymphoblastoid cell (LBC) lines from ASD patients and their parents. Analysis of CD38 mRNA levels shows that ATRA has an upmodulatory potential on LBC derived from ASD patients as well as from their parents. The next crucial issue addressed in our study was the relationship between levels of CD38 expression and psychological parameters. The results obtained indicate a positive correlation between CD38 expression levels and patient scores on the Vineland Adaptive Behavior Scale. In addition, analysis of the role of genetic polymorphisms in the dynamics of the molecule revealed that the genotype of a single-nucleotide polymorphism (rs6449182; C>G variation) in the CpG island of intron 1, harboring the retinoic-acid response element, exerts differential roles in CD38 expression in ASD and in parental LBC. In conclusion, our results provide an empirical basis for the development of a pharmacological ASD treatment strategy based on retinoids.

Genetic modification of primary chronic lymphocytic leukemia cells with a lentivirus expressing CD38

Studies of the role of individual genes in chronic lymphocytic leukemia (CLL) have been hampered by the inability to consistently transfect primary tumor cells. Here, we describe a highly efficient method of genetically modifying primary CLL cells using a VSVG pseudotyped lentiviral vector. We transduced CD38 negative CLL cells with a lentiviral vector encoding CD38 which caused increased surface CD38 expression in all the samples tested (n=17) with no evidence of plasmacytoid differentiation. The mean percentage of positive cells expressing CD38 was 87%+/-8.5% and the mean cell viability 74%+/-17%. This high level of transduction of all the CLL cell samples tested demonstrates the utility of this technique which should prove applicable for the introduction and analysis of other genes in these non-dividing cells.

Two genetic variants of CD38 in subjects with autism spectrum disorder and controls

The neurobiological basis of autism spectrum disorder (ASD) remains poorly understood. Given the role of CD38 in social recognition through oxytocin (OT) release, we hypothesized that CD38 may play a role in the etiology of ASD. Here, we first examined the immunohistochemical expression of CD38 in the hypothalamus of post-mortem brains of non-ASD subjects and found that CD38 was colocalized with OT in secretory neurons. In studies of the association between CD38 and autism, we analyzed 10 single nucleotide polymorphisms (SNPs) and mutations of CD38 by re-sequencing DNAs mainly from a case-control study in Japan, and Caucasian cases mainly recruited to the Autism Genetic Resource Exchange (AGRE). The SNPs of CD38, rs6449197 (p<0.040) and rs3796863 (p<0.005) showed significant associations with a subset of ASD (IQ>70; designated as high-functioning autism (HFA)) in the U.S. 104 AGRE family trios, but not with Japanese 188 HFA subjects. A mutation that caused tryptophan to replace arginine at amino acid residue 140 (R140W; (rs1800561, 4693C>T)) was found in 0.6-4.6% of the Japanese population and was associated with ASD in the smaller case-control study. The SNP was clustered in pedigrees in which the fathers and brothers of T-allele-carrier probands had ASD or ASD traits. In this cohort OT plasma levels were lower in subjects with the T allele than in those without. One proband with the T allele who was taking nasal OT spray showed relief of symptoms. The two variant CD38 poloymorphysms tested may be of interest with regard of the pathophysiology of ASD.

CD38/cyclic ADP-ribose system: a new player for oxytocin secretion and regulation of social behaviour

Oxytocin is important for regulating a number of physiological processes. Disruption of the secretion, metabolism or action of oxytocin results in an impairment of reproductive function, social and sexual behaviours, and stress responses. This review discusses current views on the regulation and autoregulation of oxytocin release in the hypothalamic-neurohypophysial system, with special focus on the activity of the CD38/cADP-ribose system as a new component in this regulation. Data from our laboratories indicate that an impairment of this system results in alterations of oxytocin secretion and abnormal social behaviour, thus suggesting new clues that help in our understanding of the pathogenesis of neurodevelopmental disorders.

Intrinsic and extrinsic factors influencing the clinical course of B-cell chronic lymphocytic leukemia: prognostic markers with pathogenetic relevance

B-cell chronic lymphocytic leukemia (CLL), the most frequent leukemia in the Western world, is characterized by extremely variable clinical courses with survivals ranging from 1 to more than 15 years. The pathogenetic factors playing a key role in defining the biological features of CLL cells, hence eventually influencing the clinical aggressiveness of the disease, are here divided into "intrinsic factors", mainly genomic alterations of CLL cells, and "extrinsic factors", responsible for direct microenvironmental interactions of CLL cells; the latter group includes interactions of CLL cells occurring via the surface B cell receptor (BCR) and dependent to specific molecular features of the BCR itself and/or to the presence of the BCR-associated molecule ZAP-70, or via other non-BCR-dependent interactions, e.g. specific receptor/ligand interactions, such as CD38/CD31 or CD49d/VCAM-1. A putative final model, discussing the pathogenesis and the clinicobiological features of CLL in relationship of these factors, is also provided.

Molecular and cellular mechanisms of CLL: novel therapeutic approaches

The mainstay of therapy of chronic lymphocytic leukemia (CLL) is cytotoxic chemotherapy; however, CLL is still an incurable disease with resistance to therapy developing in the majority of patients. In recent years, our understanding of the biological basis of CLL pathogenesis has substantially improved and novel treatment strategies are emerging. Tailoring and individualizing therapy according to the molecular and cellular biology of the disease is on the horizon, and advances with targeted agents such as monoclonal antibodies combined with traditional chemotherapy have lead to improved remission rates. The proposed key role of the B-cell receptor (BCR) in CLL pathogenesis has led to a number of possible opportunities for therapeutic exploitation. We are beginning to understand that the microenvironment is of utmost importance in CLL because certain T-cell subsets and stromal cells support the outgrowth and development of the malignant clone. Furthermore, an increase in our understanding of the deregulated cell-death machinery in CLL is a prerequisite to developing new targeted strategies that might be more effective in engaging with the cell-death machinery. This Review summarizes the progress made in understanding these features of CLL biology and describes novel treatment strategies that have also been exploited in current clinical trials.

p65 activity and ZAP-70 status predict the sensitivity of chronic lymphocytic leukemia cells to the selective IkappaB kinase inhibitor BMS-345541

PURPOSE

Constitutive nuclear factor-kappaB (NF-kappaB) activation has been implicated in the pathogenesis of chronic lymphocytic leukemia (CLL). Our purpose was to characterize the molecular mechanisms underlying for the selective IkappaB kinase inhibitor BMS-345541 in CLL cells together with the analysis of its combination with several antineoplasic drugs.

EXPERIMENTAL DESIGN

Primary cells from 34 CLL patients were incubated with different doses of BMS-345541. NF-kappaB DNA-binding activity was analyzed by ELISA-based kits and the characterization of the apoptotic pathway was done by flow cytometry, immunoblotting, quantitative reverse transcription-PCR, and immunofluorescence techniques.

RESULTS

BMS-345541 selectively induced apoptosis in CLL cells in the low micromolar range irrespective of p53 status. Noteworthy, the high ZAP-70 group was significantly more sensitive to BMS-345541 than the low ZAP-70 group, in correlation with high levels of p65 phosphorylation and DNA-binding activity. Following NF-kappaB inhibition, BMS-345541 led to induction of the mitochondrial apoptotic pathway and activation of both caspase-dependent and caspase-independent factors. Moreover, BMS-345541-induced apoptosis was accompanied by down-regulation of several antiapoptotic NF-kappaB-target genes, including both BCL2 family members and apoptotic endogenous inhibitors. In addition, we showed a strong synergism between BMS-345541 and conventional chemotherapeutics such as mitoxantrone and dexamethasone as well as with new promising drugs such as the BH3-mimetic GX15-070/Obatoclax or the anti-TRAIL-R1 monoclonal antibody mapatumumab.

CONCLUSIONS

These data confirm that NF-kappaB is a relevant target in CLL and indicate that inhibitors of IkappaB kinase, alone or in combination, represent a novel therapeutic strategy for the treatment of CLL patients, especially for the group with high ZAP-70.

Decreased ADP-ribosyl cyclase activity in peripheral blood mononuclear cells from diabetic patients with nephropathy

Aims/hypothesis. ADP-ribosyl-cyclase activity (ADPRCA) of CD38 and other ectoenzymes mainly generate cyclic adenosine 5’diphosphate-(ADP-) ribose (cADPR) as a second messenger in various mammalian cells, including pancreatic beta cells and peripheral blood mononuclear cells (PBMCs). Since PBMCs contribute to the pathogenesis of diabetic nephropathy, ADPRCA of PBMCs could serve as a clinical prognostic marker for diabetic nephropathy. This study aimed to investigate the connection between ADPRCA in PBMCs and diabetic complications. Methods. PBMCs from 60 diabetic patients (10 for type 1 and 50 for type 2) and 15 nondiabetic controls were fluorometrically measured for ADPRCA based on the conversion of nicotinamide guanine dinucleotide (NGD⁺) into cyclic GDP-ribose. Results. ADPRCA negatively correlated with the level of HbA1c (P = .040, R² = .073), although ADPRCA showed no significant correlation with gender, age, BMI, blood pressure, level of fasting plasma glucose and lipid levels, as well as type, duration, or medication of diabetes. Interestingly, patients with nephropathy, but not other complications, presented significantly lower ADPRCA than those without nephropathy (P = .0198) and diabetes (P = .0332). ANCOVA analysis adjusted for HbA1c showed no significant correlation between ADPRCA and nephropathy. However, logistic regression analyses revealed that determinants for nephropathy were systolic blood pressure and ADPRCA, not HbA1c. Conclusion/interpretation. Decreased ADPRCA significantly correlated with diabetic nephropathy. ADPRCA in PBMCs would be an important marker associated with diabetic nephropathy.

CD38 gene polymorphism and chronic lymphocytic leukemia: a role in transformation to Richter syndrome?

CD38 rules proliferation signals in chronic lymphocytic leukemia (CLL) cells, suggesting that the molecule is not merely a prognostic marker but also a key element in the pathogenetic network underlying the disease. CD38 has a genetic polymorphism, characterized by a C>G variation in the regulatory region of intron 1. The working hypothesis is that the presence of different alleles in CLL patients marks (or accounts for) some of the clinical heterogeneity. CD38 allele distribution in 248 Italian patients overlapped with that of the controls (n = 232), suggesting that susceptibility to CLL is not influenced by CD38 genotype. Stratification of patients according to markers of unfavorable prognosis constantly resulted in a significantly higher frequency of the rare G allele. Furthermore, analysis of clinical parameters showed that G allele is independently associated with nodal/splenic involvement. The highest G allele frequency was observed in the 16 patients of the cohort that developed Richter syndrome (RS). Five-year cumulative incidence of transformation was significantly higher in G allele carriers than in CC homozygotes. Multivariate analysis on a total of 30 RS patients confirmed that the probability of transformation is strongly associated with G allele, likely representing an independent risk factor for RS development.