Molecular detection of Epstein–Barr virus in different types of lymphoma

Molecular Biology Reports - Epstein-Barr virus (EBV) is a member of the γ herpesvirus subfamily. It is widely spread, potentially oncogenic and has been studied in different human cancers such...     

FTY720 normalizes hyperglycemia by stimulating β-cell in vivo regeneration in db/db mice through regulation of cyclin D3 and p57(KIP2)

Loss of insulin-producing β-cell mass is a hallmark of type 2 diabetes in humans and diabetic db/db mice. Pancreatic β-cells can modulate their mass in response to a variety of physiological and pathophysiological cues. There are currently few effective therapeutic approaches targeting β-cell regeneration although some anti-diabetic drugs may positively affect β-cell mass. Here we show that oral administration of FTY720, a sphingosine 1-phosphate (S1P) receptor modulator, to db/db mice normalizes fasting blood glucose by increasing β-cell mass and blood insulin levels without affecting insulin sensitivity. Fasting blood glucose remained normal in the mice even after the drug was withdrawn after 23 weeks of treatment. The islet area in the pancreases of the FTY720-treated db/db mice was more than 2-fold larger than that of the untreated mice after 6 weeks of treatment. Furthermore, BrdU incorporation assays and Ki67 staining demonstrated cell proliferation in the islets and pancreatic duct areas. Finally, islets from the treated mice exhibited a significant decrease in the level of cyclin-dependent kinase inhibitor p57(KIP2) and an increase in the level of cyclin D3 as compared with those of untreated mice, which could be reversed by the inhibition of phosphatidylinositol 3-kinase (PI3K). Our findings reveal a novel network that controls β-cell regeneration in the obesity-diabetes setting by regulating cyclin D3 and p57(KIP2) expression through the S1P signaling pathway. Therapeutic strategies targeting this network may promote in vivo regeneration of β-cells in patients and prevent and/or cure type 2 diabetes.     

From Natural Product to the First Oral Treatment for Multiple Sclerosis: The Discovery of FTY720 (Gilenya™)?

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Expression and function of T cell homing molecules in Hodgkin’s lymphoma

Circulating T lymphocytes enter a tissue if they express appropriate chemokine receptors and adhesion molecules to engage ligands presented at this site. To aid rational development of T cell-based therapies for Hodgkin's lymphoma (HL), we have assessed the expression and function of homing receptors on tumour-infiltrating T cells in HL and compared them with T cells from unaffected lymph nodes and colorectal cancer tissue. Chemokine receptors CXCR3, CXCR4 and CCR7 were expressed on a large proportion of T cells within HL tissue and mediated chemotaxis to purified chemokine. The corresponding ligands (CXCL10, CXCL12, CCL21) were expressed on the malignant cells and/or vascular endothelium. Adhesion molecules including CD62L were widely expressed on HL-derived T cells and their corresponding ligands were detected on vessels within the tumour. This homing phenotype was distinct from T cells isolated from colorectal cancer, but matched closely the phenotype of T cells from unaffected lymph nodes. Thus, T cell recruitment to HL resembles entry of na?ve/central memory T cells into normal lymph nodes. This has important implications for current approaches to treat HL using T cells activated and expanded in vitro that lack CCR7 and CD62L expression.     

Notch and NF-κB signaling pathways in the biology of classical Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is now recognized as a B-cell-derived lymphoma which is characterized by only about 1% malignant pathognomonic Hodgkin and Reed-Sternberg (HRS) cells and an abundant infiltrate of reactive bystander cells. HRS cells are unique with respect to their lost B-cell-specific gene expression pattern and recurrent genetic lesions. Aberrant activity of Notch signaling, a highly conserved developmental pathway, acts as a negative regulator of the B cell program in HRS cells and thereby contributes to their reprogramming. Another striking feature and the major pathogenetic mechanism in HRS cells is constitutive NF-κB activation. A number of aberrations that contribute to canonical NF-κB activity in HRS cells have been described such as genetic lesions, deregulated receptor signaling and Epstein-Barr virus (EBV) infection. The importance of Notch and NF-κB signaling for cHL pathogenesis, their potential cross-talk and implications for future therapeutic applications are being discussed.     

Augmentation of myelopoiesis in a murine host bearing a T cell lymphoma following in vivo administration of proton pump inhibitor pantoprazole

Proton pump inhibitors (PPI) are being proposed as potent antitumor agents, owing to their ability to specifically induce tumor cell death by reversing H⁺ ion homeostasis. As tumor growth induces myelosuppression in tumor-bearing hosts, it remains unclear if PPI can also modulate tumor-induced myelosuppression. Thus, we studied the effect of in vivo administration of pantoprazole (PPZ), a PPI, on myelopoiesis in a murine model of a transplantable T cell lymphoma, designated as Dalton’s lymphoma (DL). Intraperitoneal administration of PPZ to tumor-bearing mice resulted in an enhanced bone marrow cellularity, inhibited induction of apoptosis and augmented bone marrow cell (BMC) survival. BMC of PPZ-administered tumor-bearing mice showed elevated number of F4/80 positive cells, augmented colony forming ability and differentiation in bone marrow-derived macrophages (BMDM) with higher expression of F4/80 and CD11c markers. This study also presents evidences to indicate that PPZ-dependent augmentation of myelopoiesis in the tumor-bearing host is dependent on an enhanced expression of M-CSF and receptors for M-CSF & GM-CSF in BMC, along with a modulation in the expression of cell survival regulatory molecules PUMA, Bcl2, p53 and caspase-activated DNase (CAD). BMDM obtained from PPZ-administered tumor-bearing mice also showed an augmented expression of TLR-2, tumoricidal activity, production of NO and monokines: IL-1, IL-6 & TNF-α. The study discusses the possible mechanisms underlying PPZ-dependent augmentation of myelopoiesis. Taken together, the present study proposes that a PPZ-dependent alleviation of tumor-induced myelosuppression could contribute to an augmented myelopoiesis.     

Modulation of diphthamide synthesis by 5′-deoxy-5′-methylthioadenosine in murine lymphoma cells

The histidine derivative diphthamide occurs uniquely in eukaryotic elongation factor 2 (EF-2), and is the specific target for the diphtheria toxin mono(ADP-ribosyl)transferase. The first step in diphthamide biosynthesis may involve the transfer of an aminocarboxypropyl moiety from S-adenosylmethionine to the imidazole ring of histidine in EF-2, to yield 2-(3-carboxy-3-aminopropyl)histidine and 5′-deoxy-5′-methylthioadenosine (MeSAdo). As the possible nucleoside product of the initial reaction in the diphthamide biosynthetic pathway, MeSAdo could be an inhibitor of diphthamide formation. In the present experiments, we have analyzed the effects of MeSAdo on diphthamide synthesis in a MeSAdo phosphorylase-deficient mutant murine lymphoma cell line (R1.1, clone H3). As measured by susceptibility to diphtheria toxin-induced ADP-ribosylation, MeSAdo inhibited the formation of diphthamide in EF-2. The inhibition was not due to a nonspecific effect on protein synthesis. Indeed, exogenous MeSAdo substantially protected the lymphoma cells from the lethal effects of diphtheria toxin. These results suggest that MeSAdo can specifically modulate the biosynthesis of diphthamide in EF-2 in murine malignant lymphoma cells.     

Can paternal preconceptional radiation account for the increase of leukaemia and non-Hodgkin's lymphoma in Seascale?

OBJECTIVE--To determine if the excess of leukaemia and non-Hodgkin''s lymphoma in Seascale is restricted to those born in the parish and whether it might be explained by the postulated relation with paternal preconceptional radiation. DESIGN--Comparison, separately for those born in the parish and those born elsewhere, of the numbers of these malignancies observed in Seascale with those expected on the basis of reference rates for England and Wales. Details of paternal radiation levels were sought for each case. SETTING--The parish of Seascale in west Cumbria. SUBJECTS--Residents of Seascale below age 25 years in the years 1951-91. MAIN OUTCOME MEASURES--The observed and expected numbers of cases of leukaemia and non-Hodgkin''s lymphoma within Seascale among those born there and among those born elsewhere. Also, the levels of any paternal preconceptional radiation associated with each case. RESULTS--A significant excess of leukaemia and non-Hodgkin''s lymphoma at ages 0-24 was found in Seascale in those who were born there (ratio of observed to expected cases 8.6 and 20.2 respectively; p < 0.01). This also applied to those not born there (7.2 and 16.5; p < 0.01), a group often regarded as not showing an excess. The estimates were then conservatively recalculated so as to overestimate the risks among those born in Seascale and underestimate them among those born elsewhere. On this basis the six cases in those born in Seascale compare with 0.38 expected (15.8; p < 0.001), of which two were associated with paternal preconceptional life-time levels of 100 mSv or greater and three others with levels of 90-99 mSv. Among those born elsewhere, there were five cases (expected 0.74; ratio 6.7, p < 0.01), of which only one was associated with a high level of such radiation. CONCLUSIONS--Paternal preconceptional radiation cannot be the sole cause of the excess in Seascale since it will not explain the excess among those born outside Seascale. It follows that, unless two causes are to be postulated, any single cause must be a factor other than paternal preconceptional radiation. On this basis, the association found among those born there, if not partly due to chance, may reflect an indirect relation with the true cause. The recent hypothesis about such paternal radiation has originated in a subgroup of the excess cases that have aroused concern.     

Sulfation of keratan sulfate proteoglycan reduces radiation-induced apoptosis in human Burkitt’s lymphoma cell lines

This study focuses on clarifying the contribution of sulfation to radiation-induced apoptosis in human Burkitt’s lymphoma cell lines, using 3′-phosphoadenosine 5′-phosphosulfate transporters (PAPSTs). Overexpression of PAPST1 or PAPST2 reduced radiation-induced apoptosis in Namalwa cells, whereas the repression of PAPST1 expression enhanced apoptosis. Inhibition of PAPST slightly decreased keratan sulfate (KS) expression, so that depletion of KS significantly increased radiation-induced apoptosis. In addition, the repression of all three N-acetylglucosamine-6-O-sulfotransferases (CHST2, CHST6, and CHST7) increased apoptosis. In contrast, PAPST1 expression promoted the phosphorylation of p38 MAPK and Akt in irradiated Namalwa cells. These findings suggest that 6-O-sulfation of GlcNAc residues in KS reduces radiation-induced apoptosis of human Burkitt’s lymphoma cells.     

Curcumin induces apoptosis and inhibits growth of human Burkitt’s lymphoma in xenograft mouse model

Curcumin, a natural compound extracted from rhizomes of curcuma Curcuma species, has been shown to possess potent anti-inflammatory, anti-tumor and anti-oxidative properties. However, the mechanism of action of the compound remains poorly understood. In this report, we have analyzed the effects of curcumin on the cell proliferation of Burkitt’s lymphoma Raji cells. The results demonstrated that curcumin could effectively inhibit the growth of Raji cells in a dose- and time-dependent manner. Further studies indicated that curcumin treatment resulted in apoptosis of cells. Biochemical analysis showed that the expression of Bax, Bid and cytochrome C were up-regulated, while the expression of oncogene c-Myc was down regulated after curcumin treatment. Furthermore, poly (ADP-ribose) polymerase (PARP) cleavage was induced by the compound. Interestingly, the antiapoptotic Bcl-2 expression was not significantly changed in Raji cells after curcumin treatment. These results suggested that the mechanism of action of curcumin was to induce mitochondrial damage and therefore led to Raji cell apoptosis. We further investigated the in vivo effects of curcumin on the growth of xenograft tumors in nude mice. The results showed that curcumin could effectively inhibit tumor growth in the xenograft mouse model. The overall results showed that curcumin could suppress the growth of Burkitt’s lymphoma cells in both in vitro and in vitro systems.     

Cardiac surgery in patients irradiated for Hodgkin’s lymphoma

Background/Objectives. Therapy for Hodgkin’s lymphoma is disease specific and cannot be compared with treatment for other diseases. It often includes more extensive radiotherapy on the mediastinum than for other malignancies. Cardiac morbidity is known to occur in patients previously irradiated. This study describes the postoperative course after cardiac surgery of patients previously irradiated for Hodgkin’s lymphoma. Methods. From January 1990 until June 2008, 12 patients underwent cardiac surgery in the University Medical Center Utrecht after previous irradiation for Hodgkin’s lymphoma. Data on radiotherapy, surgery and follow-up were collected retrospectively. The postoperative functional status was assessed by a telephone questionnaire. Results. Atrial fibrillation (33%) and pleural effusion (25%) were the most common postoperative complications. After a mean followup of 2.6±2.9 years four patients had died. The remaining patients were all in a favourable New York Heart Association and Canadian Cardiothoracic Society class. The estimated one-, two- and four-year survival rates were 83, 69 and 46% respectively. Conclusion. The early postoperative outcome of cardiac surgery in this population is reasonably good. The long-term results may prove to be disappointing, but the cohort is small. (Neth Heart J 2010;18:61–5.)     

Genotoxicity of 6 oxime compounds in the Salmonella/mammalian-microsome assay and mouse lymphoma TK+/− assay

To aid in the selection of chemical candidates for in vivo tests, the mutagenicity of 6 oxime compounds was evaluated in the Salmonella plate incorporation assay and mouse lymphoma L5178Y TK^+/− assay. All of the oximes were mutagenic in the mouse lymphoma assay in the absence of exogenous metabolic activation. Acetaldehyde oxime was also mutagenic in the presence of S9 activation. In contrast to these results, a positive response was noted only for 2-(hydroxyimino)-N-phenyl-acetamide oxime in strain TA1535 in the absence of activation in the Salmonella/microsome test.     

Rituximab inhibits Kv1.3 channels in human B lymphoma cells via activation of FcγRIIB receptors

Kv1.3 channels play an important role in modulating lymphocyte proliferation and apoptosis. We hypothesized that Kv1.3 channels in B lymphocytes might be regulated by rituximab, an antibody to CD20, a drug for treatments of B-cell lymphomas and autoimmune diseases. Using both whole-cell and cell-attached patch-clamp techniques, we found that rituximab inhibited Kv1.3 channels in Daudi human B lymphoma cells by promoting the channel inactivation at a concentration which was much greater than that required for activation of CD20. The effect of rituximab on Kv1.3 channels was abolished after selective blockade of FcγRIIB receptors with anti-FcγRIIB antibody. Western blot experiments showed that Daudi B cells expressed both Kv1.3 channel and the low affinity Fc receptor, FcγRIIB, which could be activated by the Fc region of rituximab. In contrast, normal lymphocytes expressed less Kv1.3 channels with faster inactivation. Confocal microscopy and flow cytometry data showed that rituximab induced apoptosis of Daudi B cells and that the effect was attenuated by blockade of FcγRIIB receptors and partially mimicked by inhibition of Kv1.3 channels. These results suggest that in addition to previously described complement-dependent cytotoxicity, rituximab also induces apoptosis of malignant B lymphocyte by stimulating FcγRIIB receptors and inhibiting Kv1.3 channels.     

A case of hepatitis B reactivation in an anti-HBs positive, anti-HBc positive non-Hodgkin’s lymphoma patient

Dear Editor, We report a case of HBV reactivation in an anti-HBs positive,anti-HBc positive non-Hodgkin's lymphoma patient.Hepatitis B virus (HBV) reactivation is a well-recognized complication of patients undergoing chemotherapy or immunosuppressive therapy for lymphomas.The presence of antibodies to the hepatitis B surface antigen (anti-HBs) has been identified to be a factor preventing HBV reactivation in patients with occult HBV infection receiving chemotherapy.In this paper,we present a non-Hodgkin Lymphoma patient who,before immunosuppressive therapy,displayed positive anti-HBs and positive antibodies to hepatitis B core antigens (anti-HBc),as markers of resolved HBV infection,and developed hepatitis B surface antigen (HBsAg) and high viraemia with an HBV escape mutant after rituximabbased administration.The sequencing data revealed HBV genotype D with two known escape mutations,P120S.