Hepatitis B virus-related cryogobulinemic vasculitis. The role of antiviral nucleot(s)ide analogues: a review.

Cryoglobulinemic vasculitis (CV) can develop in 1.2-4% of hepatitis B virus (HBV)-infected patients. HBV infection affects about 350 million people worldwide. It can progress from acute or fulminant hepatitis to chronic hepatitis, cirrhosis or hepatocellular carcinoma. Twenty per cent of HBV patients may develop extra-hepatic manifestations, such as polyarteritis nodosa, glomerulonephritis, dermatitis, polyarthralgias and arthritis, lung disease, aplastic anaemia. Our review focuses on the role of antiviral agent nucleot(s)ide analogues (NAs) in treatment of HBV-related CV. The studies in literature have demonstrated that NAs therapy in HBV-related CV yields high virological and satisfying clinical responses in most patients with mild-and-moderate CV, but a low response in severe CV. Overall, NAs represent a promising therapeutic option for HBV-related CV. Obtaining early suppression of HBV viral load should be the main virological and clinical goal in order to prevent organ complications and lymphoproliferative disorders.

NOTCH1 mutations are associated with high CD49d expression in chronic lymphocytic leukemia: link between the NOTCH1 and the NF-κB pathways.

In chronic lymphocytic leukemia (CLL), stabilizing mutations of NOTCH1, affecting up to 10-15% of cases, have been associated to poor prognosis, disease progression and refractoriness to chemotherapy. NOTCH1 mutations are significantly overrepresented in trisomy 12 CLL, a disease subset frequently expressing CD49d, the α4 chain of the very-late-activation-4 integrin, a well-known key regulator of microenviromental interactions, and negative prognosticator in CLL. In the present study, by analysing a wide cohort of 1180 CLL, we observed a very strong association between the presence of NOTCH1 mutations and the expression of CD49d (P<0.0001), occurring also outside the trisomy 12 CLL subset. Using both the MEC-1 CLL-like cells stably transfected with the NOTCH1 intracellular domain and primary CLL cells bearing a mutated or wild-type NOTCH1 gene configuration, we provide evidence that triggering of the NOTCH1 pathway resulted in a positive CD49d expression regulation, which was driven by a NOTCH1-dependent activation of nuclear factot-κB (NF-κB). Consistently, pharmacological inhibition of the NOTCH1 and/or of the NF-κB pathways resulted in impaired NF-κB nuclear translocation with consequent down-modulation of CD49d expression. Altogether, our data link for the first time NOTCH1 mutations to CD49d expression regulation through the involvement of the NF-κB pathway in CLL.

Differences between BCL2-break positive and negative follicular lymphoma unraveled by whole-exome sequencing.

Depending on disease stage follicular lymphoma (FL) lack the t(14;18) in ~15-~50% of cases. Nevertheless, most of these cases express BCL2. To elucidate mechanisms triggering BCL2 expression and promoting pathogenesis in t(14;18)-negative FL, exonic single-nucleotide variant (SNV) profiles of 28 t(14;18)-positive and 13 t(14;18)-negative FL were analyzed, followed by the integration of copy-number changes, copy-neutral LOH and published gene-expression data as well as the assessment of immunoglobulin N-glycosylation sites. Typical FL mutations also affected t(14;18)-negative FL. Curated gene set/pathway annotation of genes mutated in either t(14;18)-positive or t(14;18)-negative FL revealed a strong enrichment of same or similar gene sets but also a more prominent or exclusive enrichment of immune response and N-glycosylation signatures in t(14;18)-negative FL. Mutated genes showed high BCL2 association in both subgroups. Among the genes mutated in t(14;18)-negative FL 555 were affected by copy-number alterations and/or copy-neutral LOH and 96 were differently expressed between t(14;18)-positive and t(14;18)-negative FL (P<0.01). N-glycosylation sites were detected considerably less frequently in t(14;18)-negative FL. These results suggest a diverse portfolio of genetic alterations that may induce or regulate BCL2 expression or promote pathogenesis of t(14;18)-negative FL as well as a less specific but increased crosstalk with the microenvironment that may compensate for the lack of N-glycosylation.

NOTCH1-mutated chronic lymphocytic leukemia cells are characterized by a MYC-related overexpression of nucleophosmin 1 and ribosome-associated components.

In chronic lymphocytic leukemia (CLL), the mechanisms controlling cell growth and proliferation in the presence of NOTCH1 mutations remain largely unexplored. By performing a gene expression profile of NOTCH1-mutated (NOTCH1-mut) versus NOTCH1 wild-type CLL, we identified a gene signature of NOTCH1-mut CLL characterized by the upregulation of genes related to ribosome biogenesis, such as nucleophosmin 1 (NPM1) and ribosomal proteins (RNPs). Activation of NOTCH1 signaling by ethylenediaminetetraacetic acid or by coculture with JAGGED1-expressing stromal cells increased NPM1 expression, and inhibition of NOTCH1 signaling by either NOTCH1-specific small interfering RNA (siRNA) or γ-secretase inhibitor reduced NPM1 expression. Bioinformatic analyses and in vitro activation/inhibition of NOTCH1 signaling suggested a role of MYC as a mediator of NOTCH1 effects over NPM1 and RNP expression in NOTCH1-mut CLL. Chromatin immunoprecipitation experiments performed on NOTCH1 intracellular domain (NICD)-transfected CLL-like cells showed the direct binding of NOTCH1 to the MYC promoter, and transfection with MYC-specific siRNA reduced NPM1 expression. In turn, NPM1 determined a proliferation advantage of CLL-like cells, as demonstrated by NPM1-specific siRNA transfection. In conclusion, NOTCH1 mutations in CLL are associated with the overexpression of MYC and MYC-related genes involved in protein biosynthesis including NPM1, which are allegedly responsible for cell growth and/or proliferation advantages of NOTCH1-mut CLL.

Venetoclax: Bcl-2 inhibition for the treatment of chronic lymphocytic leukemia.

Venetoclax (ABT-199) is a small-molecule selective oral inhibitor of the antiapoptotic protein Bcl-2 that promotes programmed cell death of chronic lymphocytic leukemia (CLL) cells regulating the release of proapoptotic factors, such as Smac/Diablo, apoptosis-inducing factor (AIF) and cytochrome c. In April 2016, the U.S. Food and Drug Administration (FDA) granted accelerated approval to venetoclax for patients diagnosed with CLL with 17p deletion, as detected by an FDA-approved test, who have received at least one prior therapy. This review will focus on the mechanism of action, preclinical studies and clinical development of venetoclax both as a monotherapy and in combination with other drugs for CLL in the current milieu of therapy dominated by novel tyrosine kinase inhibitors such as ibrutinib and idelalisib.

CD49d prevails over the novel recurrent mutations as independent prognosticator of overall survival in chronic lymphocytic leukemia.

CD49d, the alpha-chain of the integrin heterodimer α4ß1, was identified among the strongest predictors of overall survival (OS) in chronic lymphocytic leukemia (CLL), along with IGHV mutational status and deletion of the 17p chromosome involving TP53. In addition to TP53, the clinical relevance of NOTCH1, SF3B1 and BIRC3 gene mutations has been recently emphasized. By analyzing a cohort of 778 unselected CLL patients, we assessed the clinical relevance of CD49d as an OS predictor in subgroups defined by mutation/deletion of the TP53, NOTCH1, SF3B1 and BIRC3 genes. In this context, CD49d emerged as an independent predictor of OS in multivariate Cox analysis (Hazard ratio =1.88, P<0.0001). Consistently, high CD49d expression identified CLL subsets with inferior OS in the context of each category of a previously reported hierarchical risk stratification model. Moreover, by evaluating the relative importance of biological prognosticators by random survival forests, CD49d was selected among the top-ranked OS predictor (variable importance =0.0410), along with IGHV mutational status and TP53 abnormalities. These results confirmed CD49d as an independent negative OS prognosticator in CLL also in comprehensive models comprising the novel recurrent mutations. In this context, TP53 disruption and NOTCH1 mutations retained prognostic relevance, in keeping with their roles in CLL cell immuno-chemoresistance.

NOTCH1 mutations associate with low CD20 level in chronic lymphocytic leukemia: evidence for a NOTCH1 mutation-driven epigenetic dysregulation.

In chronic lymphocytic leukemia (CLL), NOTCH1 mutations have been associated with clinical resistance to the anti-CD20 rituximab, although the mechanisms behind this peculiar behavior remain to be clarified. In a wide CLL series (n=692), we demonstrated that CLL cells from NOTCH1-mutated cases (87/692) were characterized by lower CD20 expression and lower relative lysis induced by anti-CD20 exposure in vitro. Consistently, CD20 expression by CLL cells was upregulated in vitro by γ-secretase inhibitors or NOTCH1-specific small interfering RNA and the stable transfection of a mutated (c.7541-7542delCT) NOTCH1 intracellular domain (NICD-mut) into CLL-like cells resulted in a strong downregulation of both CD20 protein and transcript. By using these NICD-mut transfectants, we investigated protein interactions of RBPJ, a transcription factor acting either as activator or repressor of NOTCH1 pathway when respectively bound to NICD or histone deacetylases (HDACs). Compared with controls, NICD-mut transfectants had RBPJ preferentially complexed to NICD and showed higher levels of HDACs interacting with the promoter of the CD20 gene. Finally, treatment with the HDAC inhibitor valproic acid upregulated CD20 in both NICD-mut transfectants and primary CLL cells. In conclusion, NOTCH1 mutations are associated with low CD20 levels in CLL and are responsible for a dysregulation of HDAC-mediated epigenetic repression of CD20 expression.

Bispecific antibodies targeting tumor-associated antigens and neutralizing complement regulators increase the efficacy of antibody-based immunotherapy in mice.

The efficacy of antibody-based immunotherapy is due to the activation of apoptosis, the engagement of antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity (CDC). We developed a novel strategy to enhance CDC using bispecific antibodies (bsAbs) that neutralize the C-regulators CD55 and CD59 to enhance C-mediated functions. Two bsAbs (MB20/55 and MB20/59) were designed to recognize CD20 on one side. The other side neutralizes CD55 or CD59. Analysis of CDC revealed that bsAbs could kill 4-25 times more cells than anti-CD20 recombinant antibody in cell lines or cells isolated from patients with chronic lymphocytic leukemia. The pharmacokinetics of the bsAbs was evaluated in a human-SCID model of Burkitt lymphoma. The distribution profile of bsAbs mimics the data obtained by studying the pharmacokinetics of anti-CD20 antibodies, showing a peak in the tumor mass 3-4 days after injection. The treatment with bsAbs completely prevented the development of human/SCID lymphoma. The tumor growth was blocked by the activation of the C cascade and by the recruitment of macrophages, polymorphonuclear and natural killer cells. This strategy can easily be applied to the other anti-tumor C-fixing antibodies currently used in the clinic or tested in preclinical studies using the same vector with the appropriate modifications.

The enzymatic activities of CD38 enhance CLL growth and trafficking: implications for therapeutic targeting.

The ecto-enzyme CD38 is gaining momentum as a novel therapeutic target for patients with hematological malignancies, with several anti-CD38 monoclonal antibodies in clinical trials with promising results. In chronic lymphocytic leukemia (CLL) CD38 is a marker of unfavorable prognosis and a central factor in the pathogenetic network underlying the disease: activation of CD38 regulates genetic pathways involved in proliferation and movement. Here we show that CD38 is enzymatically active in primary CLL cells and that its forced expression increases disease aggressiveness in a xenograft model. The effect is completely lost when using an enzyme-deficient version of CD38 with a single amino-acid mutation. Through the enzymatic conversion of NAD into ADPR (ADP-ribose) and cADPR (cyclic ADP-ribose), CD38 increases cytoplasmic Ca(2+) concentrations, positively influencing proliferation and signaling mediated via chemokine receptors or integrins. Consistently, inhibition of the enzymatic activities of CD38 using the flavonoid kuromanin blocks CLL chemotaxis, adhesion and in vivo homing. In a short-term xenograft model using primary cells, kuromanin treatment traps CLL cells in the blood, thereby increasing responses to chemotherapy. These results suggest that monoclonal antibodies that block the enzymatic activities of CD38 or enzyme inhibitors may prove therapeutically useful.

The CD49d/CD29 complex is physically and functionally associated with CD38 in B-cell chronic lymphocytic leukemia cells.

CD49d and CD38 are independent negative prognostic markers in chronic lymphocytic leukemia (CLL). Their associated expression marks a disease subset with a highly aggressive clinical course. Here, we demonstrate a constitutive physical association between the CD49d/CD29 integrin complex and CD38 in primary CLL cells and B-cell lines by (i) cocapping, (ii) coimmunoprecipitation and (iii) cell adhesion experiments using CD49d-specific substrates (vascular-cell adhesion molecule-1 or CS-1/H89 fibronectin fragments). The role of CD38 in CD49d-mediated cell adhesion was studied in CD49d(+)CD38(+) and CD49d(+)CD38(-) primary CLL cells, and confirmed using CD38 transfectants of the originally CD49d(+)CD38(-) CLL-derived cell line Mec-1. Results indicate that CD49d(+)CD38(+) cells adhered more efficiently onto CD49d-specific substrates than CD49d(+)CD38(-) cells (P < 0.001). Upon adhesion, CD49d(+)CD38(+) cells underwent distinctive changes in cell shape and morphology, with higher levels of phosphorylated Vav-1 than CD49d(+)CD38(-) cells (P = 0.0006) and a more complex distribution of F-actin to the adhesion sites. Lastly, adherent CD49d(+)CD38(+) cells were more resistant to serum-deprivation-induced (P < 0.001) and spontaneous (P = 0.03) apoptosis than the CD49d(+)CD38(-) counterpart. Altogether, our results point to a direct role for CD38 in enhancing CD49d-mediated adhesion processes in CLL, thus providing an explanation for the negative clinical impact exerted by these molecules when coexpressed in neoplastic cells.

The miR-17∼92 family regulates the response to Toll-like receptor 9 triggering of CLL cells with unmutated IGHV genes.

Chronic lymphocytic leukemia (CLL) cells from clinically aggressive cases have a greater capacity to respond to external microenvironmental stimuli, including those transduced through Toll-like-receptor-9 (TLR9). Concomitant microRNA and gene expression profiling in purified CLL cells (n=17) expressing either unmutated (UM) or mutated (M) IGHV genes selected microRNAs from the miR-17∼92 family as significantly upregulated and in part responsible for modifications in the gene expression profile of UM CLL cells stimulated with the TLR9 agonist CpG. Notably, the stable and sustained upregulation of miR-17∼92 microRNAs by CpG was preceded by a transient induction of the proto-oncogene MYC. The enforced expression of miR-17, a major member from this family, reduced the expression of the tumor suppressor genes E2F5, TP53INP1, TRIM8 and ZBTB4, and protected cells from serum-free-induced apoptosis (P ≤ 0.05). Consistently, transfection with miR-17∼92 family antagomiRs reduced Bromo-deoxy-uridine incorporation in CpG-stimulated UM CLL cells. Finally, miR-17 expression levels, evaluated in 83 CLL samples, were significantly higher in UM (P=0.03) and ZAP-70(high) (P=0.02) cases. Altogether, these data reveal a role for microRNAs of the miR-17∼92 family in regulating pro-survival and growth-promoting responses of CLL cells to TLR9 triggering. Overall, targeting of this pathway may represent a novel therapeutic option for management of aggressive CLL.

A new freezing and storage procedure improves safety and viability of haematopoietic stem cells and neutrophil engraftment: a single institution experience.

BACKGROUND AND OBJECTIVES: Autologous peripheral blood stem cell transplantation has recently become a standard therapeutic approach to virus-related or infected haematological malignancies. Collection, manipulation, storage and thawing of leukapheresis products in this subset of patients require strict monitoring to prevent infection risk for operators and risk of contamination for other stored bags. MATERIALS AND METHODS: This is a non-randomized retrospective observational study. In the 2000-2002 period, a single bag freezing procedure was used for autologous peripheral blood stem cell transplantation. Bags were stored in tanks containing liquid and gas phase nitrogen. In 2002, the processing procedure was revised, and a second additional safety bag and a new storage tank containing jacketed liquid nitrogen have been used. RESULTS: A total of 524 bags were thawed, of which 121 processed with the single bag method and 403 with the double bag method. Forty-nine and 109 patients were infused respectively. The observed rupture rate with the single bag in liquid and gas phase nitrogen was 17 and 2.5%, respectively, against a rupture rate as little as 0.24% with the new methodology. Viability revealed levels of 84.4% +/- 6.1% and 96.9% +/- 2.4% for the single and double-bag respectively. This statistically significant (P < 0.0001) difference correlated with better neutrophil engraftment. CONCLUSIONS: The new proposed method, based on a double bag and storage freezer without liquid or gas phase nitrogen into a cryogenic chamber, significantly reduces bag rupture and bio-hazard and improves stem cell viability and neutrophil engraftment remarkably.

Exposure of B cell chronic lymphocytic leukemia (B-CLL) cells to nutlin-3 induces a characteristic gene expression profile, which correlates with nutlin-3-mediated cytotoxicity.

By analyzing the cDNA obtained from 16 B-cell chronic lymphocytic leukemia (B-CLL) patient samples, we found that Nutlin-3, a small molecule inhibitor of MDM2/p53 interaction, induced a characteristic gene expression profile (GEP) signature in 13 out of 16 B-CLL samples. The lack of Nutlin-3-induced GEP signature in 3 out of 16 B-CLL samples was not due to p53 deletion and/or mutation, as demonstrated by FISH analysis and p53 sequencing. Of note, the 3 B-CLL samples in which Nutlin-3 did not elicit the GEP signature were also less susceptible to Nutlin-3-mediated cytotoxicity with respect to the remaining 13 B-CLL samples. However, the partial lack of response in these p53 wild-type B-CLL samples was not due to defects in the ability of Nutlin-3 to promote p53 induction, as confirmed by the rapid accumulation of p53 protein at Western blot analysis in response to Nutlin-3 in all samples examined. Upon exposure to Nutlin-3, the genes up-regulated with the highest score in the majority of B-CLL cells were all known p53-target genes, including genes involved in apoptotic pathways, such as FAS and BAX, as well as MDM2. Taken together, our data indicate that the ability of Nutlin-3 to induce a characteristic GEP signature correlates with its cytotoxic potential in p53 wild-type B-CLL cells. However, in some p53 wild-type B-CLL samples, the response to Nutlin-3 cannot be predicted on the basis of FISH analysis or p53 sequencing.

Preclinical ex vivo expansion of peripheral blood CD34+ selected cells from cancer patients mobilized with combination chemotherapy and granulocyte colony-stimulating factor.

BACKGROUND AND OBJECTIVES: Ex vivo peripheral blood progenitor cell (PBPC) expansion has been proposed as a strategy to increase the number of haematopoietic progenitors available for cell transplantation. We have expanded CD34+ cells from PBPCs obtained from four patients with haematological malignancies and one patient with an Ewing's sarcoma. MATERIALS AND METHODS: Cells were expanded in the Dideco 'Pluricell system'. After 12 days in culture, we evaluated cell phenotype, total nucleated cells, CD34+ fold increase, cell apoptosis and colony assay of expanded cells. Cell engraftment has been evaluated by transplanting two groups of irradiated non-obese diabetic/severe combined immunodeficient (NOD-SCID) mice with expanded and non-expanded cell populations. RESULTS: Total nucleated cells and CD34+ cells increased 59.5 and 4.0 times, respectively. The expanded cells were mainly constituted of myeloid and megakaryocytic cells. A significant increase in the number of colony-forming unit-granulocyte macrophage (CFU-GM) was observed in the CFU assay. Ten mice transplanted with expanded cells showed a best overall survival (80%) compared to 10 mice transplanted with non-expanded cells (20%). Human CD45+ cells were detected by flow cytometry and polymerase chain reaction in bone marrow and spleen of transplanted animals. The relative low engraftment level obtained with the expanded cells suggests a loss of SCID repopulating cells maybe due to cell differentiation during expansion. CONCLUSIONS: We have demonstrated the feasibility of the ex vivo expansion of mobilized PBPCs from cancer patients, evidencing a clonal expansion of CFUs and the ability of the expanded cells to engraft the bone marrow and spleen of immunosuppressed mice. The differentiation of the CD34+ stem cell compartment could be further minimized by ameliorating the expansion conditions.