Characterization of NF-kappaB expression in Hodgkin's disease: inhibition of constitutively expressed NF-kappaB results in spontaneous caspase-independent apoptosis in Hodgkin and Reed-Sternberg cells

Mechanism of action and therapeutic targeting of CD30 molecule in lymphomas

At present, the treatment of lymphoma has entered the era of precision medicine, and CD30, as a transmembrane protein, has become an important marker to help the diagnosis and formulation of treatment plans for lymphomas. This protein is widely expressed in various types of lymphomas and can play a role through nuclear factor-κB (NF-κB), mitogen-activated protein kinase (MAPK), and other pathways, and ultimately lead to the up-regulation of CD30 expression to give tumor cells a survival advantage. Brentuximab vedotin (BV), as an antibody-drug conjugate (ADC) targeting CD30, is one of the first new drugs to significantly improve survival in patients with CD30+lymphomas. However, the biological function of CD30 has not been fully elucidated. Therefore, this review highlights the CD30-mediated tumor-promoting mechanisms and the molecular factors that regulate CD30 expression. We hope that a better understanding of CD30 biology will provide new insights into clinical treatment and improve the survival and quality of life of lymphoma patients.

Inhibitors of SARS-CoV-2 main protease: Biological efficacy and toxicity aspects

The emergence of the highly contagious respiratory disease, COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a significant global public health concern. To combat this virus, researchers have focused on developing antiviral strategies that target specific viral components, such as the main protease (Mpro), which plays a crucial role in SARS-CoV-2 replication. While many compounds have been identified as potent inhibitors of Mpro, only a few have been translated into clinical use due to the potential risk-benefit trade-offs. Development of systemic inflammatory response and bacterial co-infection in patients belong to severe, frequent complications of COVID-19. In this context, we analysed available data on the anti-inflammatory and antibacterial activities of the SARS-CoV-2 Mpro inhibitors for possible implementation in the treatment of complicated and long COVID-19 cases. Synthetic feasibility and ADME properties were calculated and included for better characterisation of the compounds' predicted toxicity. Analysis of the collected data resulted in several clusters pointing to the most prospective compounds for further study and design. The complete tables with collected data are attached in Supplementary material for use by other researchers.

BET inhibitors induce NF-κB and E2F downregulation in Hodgkin and Reed-Sternberg cells

The prognosis of patients with relapsed and/or refractory classic Hodgkin lymphoma (cHL) continues to be poor. Therefore, there is a continuing need to develop novel therapies and to rationalize the use of target combinations. In recent years there has been growing interest in epigenetic targets for hematological malignancies under the rationale of the presence of common alterations in epigenetic transcriptional regulation. Since Hodgkin and Reed-Sternberg (HRS) cells have frequent inactivating mutations of the CREBBP and EP300 acetyltransferases, bromodomain and extra-terminal (BET) inhibitors can be a rational therapy for cHL. Here we aimed to confirm the efficacy of BET inhibitors (iBETs) using representative cell models and functional experiments, and to further explore biological mechanisms under iBET treatment using whole-transcriptome analyses. Our results reveal cytostatic rather than cytotoxic activity through the induction of G1/S and G2/M cell-cycle arrest, in addition to variable MYC downregulation. Additionally, massive changes in the transcriptome induced by the treatment include downregulation of relevant pathways in cHL disease: NF-kB and E2F, among others. Our findings support the therapeutic use of iBETs in selected cHL patients and reveal previously unknown biological mechanisms and consequences of pan-BET inhibition.

Resveratrol triggers the ER stress-mediated intrinsic apoptosis of neuroblastoma cells coupled with suppression of Rho-dependent migration and consequently prolongs mouse survival

Neuroblastoma, the most common childhood tumor, are highly malignant and fatal because neuroblastoma cells extremely defend against apoptotic targeting. Traditional treatments for neuroblastomas are usually ineffective and lead to serious side effects and poor prognoses. In this study, we investigated the molecular mechanisms of resveratrol-induced insults to neuroblastoma cells and survival extension of nude mice with neuroblastomas, especially in the endoplasmic reticular (ER) stress-intracellular reactive oxygen species (iROS) axis-mediated signals. Resveratrol specifically killed neuroblastoma cells mainly via apoptosis and autophagy rather than necrosis. As to the mechanisms, resveratrol time-dependently triggered productions of Grp78 protein and iROS in neuroblastoma cells. Attenuating the ER stress-iROS signaling axis significantly suppressed resveratrol-induced autophagy, DNA damage, and cell apoptosis. Successively, resveratrol decreased phosphorylation of retinoblastoma protein and induced cell cycle arrest at the S phase, translocation of Bak protein to mitochondria, a reduction in the mitochondrial membrane potential, cascade activation of caspases-9, -3, and -6, and DNA fragmentation. Moreover, weakening the ER stress-iROS axis concomitantly overcome resveratrol-induced decreases in translocation of Rho protein to membranes and succeeding cell migration. Interestingly, administration of resveratrol did not cause significant side effects but could protect the neuroblastoma-bearing nude mice from body weight loss and consequently extended the animal survival. In parallel, resveratrol elevated levels of Grp78 and then induced cell apoptosis in neuroblastoma tissues. This study has shown that resveratrol could kill neuroblastoma cells and extend survival of animals with neuroblastomas by triggering the ER stress-iROS-involved intrinsic apoptosis and suppression of Rho-dependent cell migration. Our results imply the potential of resveratrol as a drug candidate for chemotherapy of neuroblastoma patients.

Epipolythiodioxopiperazine-Based Natural Products: Building Blocks, Biosynthesis and Biological Activities

Epipolythiodioxopiperazines (ETPs) are fungal secondary metabolites that share a 2,5-diketopiperazine scaffold built from two amino acids and bridged by a sulfide moiety. Modifications of the core and the amino acid side chains, for example by methylations, acetylations, hydroxylations, prenylations, halogenations, cyclizations, and truncations create the structural diversity of ETPs and contribute to their biological activity. However, the key feature responsible for the bioactivities of ETPs is their sulfide moiety. Over the last years, combinations of genome mining, reverse genetics, metabolomics, biochemistry, and structural biology deciphered principles of ETP production. Sulfurization via glutathione and uncovering of the thiols followed by either oxidation or methylation crystallized as fundamental steps that impact expression of the biosynthesis cluster, toxicity and secretion of the metabolite as well as self-tolerance of the producer. This article showcases structure and activity of prototype ETPs such as gliotoxin and discusses the current knowledge on the biosynthesis routes of these exceptional natural products.

NFkB Pathway and Hodgkin Lymphoma

The tumor cells that drive classical Hodgkin lymphoma (cHL), namely, Hodgkin and Reed-Sternberg (HRS) cells, display hallmark features that include their rareness in contrast with an extensive and rich reactive microenvironment, their loss of B-cell phenotype markers, their immune escape capacity, and the activation of several key biological pathways, including the constitutive activation of the NFkB pathway. Both canonical and alternative pathways are deregulated by genetic alterations of their components or regulators, EBV infection and interaction with the microenvironment through multiple receptors, including CD30, CD40, BAFF, RANK and BCMA. Therefore, NFkB target genes are involved in apoptosis, cell proliferation, JAK/STAT pathway activation, B-cell marker expression loss, cellular interaction and a positive NFkB feedback loop. Targeting this complex pathway directly (NIK inhibitors) or indirectly (PIM, BTK or NOTCH) remains a challenge with potential therapeutic relevance. Nodular predominant HL (NLPHL), a distinct and rare HL subtype, shows a strong NFkB activity signature because of mechanisms that differ from those observed in cHL, which is discussed in this review.

Distinct 3D Structural Patterns of Lamin A/C Expression in Hodgkin and Reed-Sternberg Cells

Classical Hodgkin's lymphoma (cHL) is a B-Cell lymphoma comprised of mononuclear Hodgkin cells (H) and bi- to multi-nucleated Reed-Sternberg (RS) cells. Previous studies revealed that H and RS cells express lamin A/C, a component of the lamina of the nuclear matrix. Since no information was available about the three-dimensional (3D) expression patterns of lamin A/C in H and RS cells, we analyzed the 3D spatial organization of lamin in such cells, using 3D fluorescent microscopy. H and RS cells from cHL derived cell lines stained positive for lamin A/C, in contrast to peripheral blood lymphocytes (PBLs), in which the lamin A/C protein was not detected or weak, although its presence could be transiently increased with lymphocyte activation by lipopolysaccharide (LPS). Most importantly, in H and RS cells, the regular homogeneous and spherically shaped lamin A/C pattern, identified in activated lymphocytes, was absent. Instead, in H and RS cells, lamin staining showed internal lamin A/C structures, subdividing the nuclei into two or more smaller compartments. Analysis of pre-treatment cHL patients' samples replicated the lamin patterns identified in cHL cell lines. We conclude that the investigation of lamin A/C protein could be a useful tool for understanding nuclear remodeling in cHL.

Genome-wide association study of classical Hodgkin lymphoma identifies key regulators of disease susceptibility

Several susceptibility loci for classical Hodgkin lymphoma have been reported. However, much of the heritable risk is unknown. Here, we perform a meta-analysis of two existing genome-wide association studies, a new genome-wide association study, and replication totalling 5,314 cases and 16,749 controls. We identify risk loci for all classical Hodgkin lymphoma at 6q22.33 (rs9482849, P = 1.52 × 10-8) and for nodular sclerosis Hodgkin lymphoma at 3q28 (rs4459895, P = 9.43 × 10-17), 6q23.3 (rs6928977, P = 4.62 × 10-11), 10p14 (rs3781093, P = 9.49 × 10-13), 13q34 (rs112998813, P = 4.58 × 10-8) and 16p13.13 (rs34972832, P = 2.12 × 10-8). Additionally, independent loci within the HLA region are observed for nodular sclerosis Hodgkin lymphoma (rs9269081, HLA-DPB1*03:01, Val86 in HLA-DRB1) and mixed cellularity Hodgkin lymphoma (rs1633096, rs13196329, Val86 in HLA-DRB1). The new and established risk loci localise to areas of active chromatin and show an over-representation of transcription factor binding for determinants of B-cell development and immune response.

Expression of PIM kinases in Reed-Sternberg cells fosters immune privilege and tumor cell survival in Hodgkin lymphoma

Reed-Sternberg (RS) cells of classical Hodgkin lymphoma (cHL) express multiple immunoregulatory proteins that shape the cHL microenvironment and allow tumor cells to evade immune surveillance. Expression of certain immunoregulatory proteins is modulated by prosurvival transcription factors, such as NFκB and STATs. Because these factors also induce expression of the oncogenic PIM1/2/3 serine/threonine kinases, and as PIMs modulate transcriptional activity of NFκB and STATs, we hypothesized that these kinases support RS cell survival and foster their immune privilege. Here, we investigated PIM1/2/3 expression in cHL and assessed their role in developing RS cell immune privilege and survival. PIM1/2/3 were ubiquitously expressed in primary and cultured RS cells, and their expression was driven by JAK-STAT and NFκB activity. Genetic or chemical PIM inhibition with a newly developed pan-PIM inhibitor, SEL24-B489, induced RS cell apoptosis. PIM inhibition decreased cap-dependent protein translation, blocked JAK-STAT signaling, and markedly attenuated NFκB-dependent gene expression. In a cHL xenograft model, SEL24-B489 delayed tumor growth by 95.8% (P = .0002). Furthermore, SEL24-B489 decreased the expression of multiple molecules engaged in developing the immunosuppressive microenvironment, including galectin-1 and PD-L1/2. In coculture experiments, T cells incubated with SEL24-B489-treated RS cells exhibited higher expression of activation markers than T cells coincubated with control RS cells. Taken together, our data indicate that PIM kinases in cHL exhibit pleiotropic effects, orchestrating tumor immune escape and supporting RS cell survival. Inhibition of PIM kinases decreases RS cell viability and disrupts signaling circuits that link these cells with their niches. Thus, PIM kinases are promising therapeutic targets in cHL.

Relevance of the Measles Virus Expression in Cancer - an Update

Evidence of an association between classical Hodgkin lymphoma and the measles virus has previously been presented by our group. Arguments held against our thesis were reevaluated. Substantiation of a relationship between the measles virus and additional solid tumors was submitted. Moreover, a pathogenic pathway was suggested to support a possible contribution of the measles virus to the development of classical Hodgkin lymphoma. We have chosen to exclude a discussion of measles virotherapy, since this carries distinct implications. We now add new evidence regarding the expression of the measles virus phosphoprotein in a few cancers. We also suggest a role in this context for atypical measles syndrome in malignant tumors. Last, we propose a collaboration which may make the best, on the one hand of our cohort of classical Hodgkin lymphoma, half of which carry the measles virus expression in their tumor cells. The planned study will also look into the patients vaccination records and into a previous history of the measles disease. On the other hand, cohorts of patients diagnosed with late onset measles will be assessed for the eventual diagnosis of atypical measles syndrome and will be followed up for the subsequent development of a malignant tumor.

NF-κB deregulation in Hodgkin lymphoma

Hodgkin and Reed/Sternberg (HRS) cells in classical Hodgkin lymphoma (HL) show constitutive activity of both the canonical and non-canonical NF-κB signaling pathways. The central pathogenetic role of this activity is indicated from studies with HL cell lines, which undergo apoptosis upon NF-κB inhibition. Multiple factors contribute to the strong NF-κB activity of HRS cells. This includes interaction with other cells in the lymphoma microenvironment through CD30, CD40, BCMA and other receptors, but also recurrent somatic genetic lesions in various factors of the NF-κB pathway, including destructive mutations in negative regulators of NF-κB signaling (e.g. TNFAIP3, NFKBIA), and copy number gains of genes encoding positive regulators (e.g. REL, MAP3K14). In Epstein-Barr virus-positive cases of classical HL, the virus-encoded latent membrane protein 1 causes NF-κB activation by mimicking an active CD40 receptor. NF-κB activity is also seen in the tumor cells of the rare nodular lymphocyte predominant form of HL, but the causes for this activity are largely unclear.

Gliotoxin--bane or boon?

Gliotoxin (GT) is the most important epidithiodioxopiperazine (ETP)-type fungal toxin. GT was originally isolated from Trichoderma species as an antibiotic substance involved in biological control of plant pathogenic fungi. A few isolates of GT-producing Trichoderma virens are commercially marketed for biological control and widely used in agriculture. Furthermore, GT is long known as an immunosuppressive agent and also reported to have anti-tumour properties. However, recent publications suggest that GT is a virulence determinant of the human pathogen Aspergillus fumigatus. This compound is thus important on several counts - it has medicinal properties, is a pathogenicity determinant, is a potential diagnostic marker and is important in biological crop protection. The present article addresses this paradox and the ecological role of GT. We discuss the function of GT as defence molecule, the role in aspergillosis and suggest solutions for safe application of Trichoderma-based biofungicides.

PTPIP51—A New RelA-tionship with the NFκB Signaling Pathway

The present study shows a new connection of protein tyrosine phosphatase interacting protein 51 (PTPIP51) to the nuclear factor κB (NFκB) signalling pathway. PTPIP51 mRNA and protein expression is regulated by RelA. If bound to the PTPIP51 promoter, RelA repress the mRNA and protein expression of PTPIP51. The parallel treatment with pyrrolidine dithiocarbamate (PDTC) reversed the suppression of PTPIP51 protein expression induced by TNFα. Using the intensity correlation analysis PTPIP51 verified a co-localization with RelA, which is also regulated by TNFα administration. Moreover, the direct interaction of PTPIP51 and RelA was established using the DuoLink proximity ligation assay. IκBα, the known inhibitor of RelA, also interacted with PTPIP51. This hints to the fact that in un-stimulated conditions PTPIP51 forms a complex with RelA and IκBα. The PTPIP51/RelA/IκBα complex is modulated by TNFα. Interestingly, the impact on the mitogen activated protein kinase pathway was negligible except in highest TNFα concentration. Here, PTPIP51 and Raf-1 interactions were slightly repressed. The newly established relationship of PTPIP51 and the NFκB signaling pathway provides the basis for a possible therapeutic impact.

Contribution of the Epstein-Barr Virus to the Pathogenesis of Hodgkin Lymphoma

The morphology of the pathognomonic Hodgkin and Reed-Sternberg cells (HRS) of Hodgkin lymphoma was described over a century ago, yet it was only relatively recently that the B-cell origin of these cells was identified. In a proportion of cases, HRS cells harbour monoclonal forms of the B lymphotropic Epstein-Barr virus (EBV). This review summarises current knowledge of the pathogenesis of Hodgkin lymphoma with a particular emphasis on the contribution of EBV.

Does the measles virus contribute to carcinogenesis? - a review

An association between the measles virus and classical Hodgkin lymphoma has previously been suggested by us. This has been refuted by two European groups. A reevaluation of the arguments held against our thesis was carried out and further evidence for a relationship between the measles virus and additional solid tumors has been presented. We have suggested a molecular mechanism to support a possible contribution of the virus to carcinogenesis in classical Hodgkin lymphoma.

The Concise Guide to PHARMACOLOGY 2013/14: enzymes

The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. Enzymes are one of the seven major pharmacological targets into which the Guide is divided, with the others being G protein-coupled receptors, ligand-gated ion channels, ion channels, nuclear hormone receptors, catalytic receptors and transporters. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors and Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and the Guide to Receptors and Channels, providing a permanent, citable, point-in-time record that will survive database updates.

Role of immune escape mechanisms in Hodgkin's lymphoma development and progression: a whole new world with therapeutic implications

Hodgkin's lymphoma represents one of the most frequent lymphoproliferative syndromes, especially in young population. Although HL is considered one of the most curable tumors, a sizeable fraction of patients recur after successful upfront treatment or, less commonly, are primarily resistant. This work tries to summarize the data on clinical, histological, pathological, and biological factors in HL, with special emphasis on the improvement of prognosis and their impact on therapeutical strategies. The recent advances in our understanding of HL biology and immunology show that infiltrated immune cells and cytokines in the tumoral microenvironment may play different functions that seem tightly related with clinical outcomes. Strategies aimed at interfering with the crosstalk between tumoral Reed-Sternberg cells and their cellular partners have been taken into account in the development of new immunotherapies that target different cell components of HL microenvironment. This new knowledge will probably translate into a change in the antineoplastic treatments in HL in the next future and hopefully will increase the curability rates of this disease.

A nationwide study of aspirin, other non-steroidal anti-inflammatory drugs, and Hodgkin lymphoma risk in Denmark

BACKGROUND

We recently found an inverse association between low-dose aspirin use and risk of Hodgkin lymphoma (HL) in northern Denmark. To strengthen the evidence for this association, we expanded the study base to include all of Denmark.

METHODS

Between 1997 and 2009, 1659 incident HL cases were identified in nationwide databases and matched with ≤5 population controls on age, sex, and residence. Use of aspirin, selective cyclooxygenase-2 (sCOX-2) inhibitors, and other non-steroidal anti-inflammatory drugs (NSAIDs) from 1995 through 2008 (≥1 year before the index date) was ascertained via the Danish National Prescription Database. Odds ratios (ORs) for associations with HL risk were estimated using conditional logistic regression.

RESULTS

Ever use (>2 prescriptions) vs never/rare use (≤2 prescriptions) of low-dose aspirin was not associated with HL risk, but the association with long-term use for ≥7 years vs never/rare use was clearly inverse, although statistically nonsignificantly so (OR=0.65, 95% confidence interval (CI): 0.39-1.09). By contrast, ever use of sCOX-2 inhibitors or other NSAIDs (OR=1.27, 95% CI: 1.10-1.47), especially short-term and low- or medium-intensity use, was associated with elevated HL risk.

CONCLUSION

Our results are consistent with the hypothesis that long-term use of low-dose aspirin, but not other NSAIDs, protects against HL development.

KLF4 is a tumor suppressor in B-cell non-Hodgkin lymphoma and in classic Hodgkin lymphoma

The transcription factor KLF4 may act both as an oncogene and a tumor suppressor in a tissue-depending manner. In T- and pre-B-cell lymphoma, KLF4 was found to act as tumor suppressor. We found the KLF4 promoter methylated in B-cell lymphoma cell lines and in primary cases of B-cell lymphomas, namely, follicular lymphoma, diffuse large B-cell lymphoma, Burkitt lymphoma, and in classic Hodgkin lymphoma (cHL) cases. Promoter hypermethylation was associated with silencing of KLF4 expression. Conditional overexpression of KLF4 in Burkitt lymphoma cell lines moderately retarded proliferation, via cell-cycle arrest in G(0)/G(1). In the cHL cell lines, KLF4 induced massive cell death that could partially be inhibited with Z-VAD.fmk. A quantitative reverse-transcribed polymerase chain reaction array revealed KLF4 target genes, including the proapoptotic gene BAK1. Using an shRNA-mediated knock-down approach, we found that BAK1 is largely responsible for KLF4-induced apoptosis. In addition, we found that KLF4 negatively regulates CXCL10, CD86, and MSC/ABF-1 genes. These genes are specifically up-regulated in HRS cells of cHL and known to be involved in establishing the cHL phenotype. We conclude that epigenetic silencing of KLF4 in B-cell lymphomas and particularly in cHL may favor lymphoma survival by loosening cell-cycle control and protecting from apoptosis.

Aspirin and other nonsteroidal anti-inflammatory drugs in relation to Hodgkin lymphoma risk in northern Denmark

There are few known modifiable risk factors for Hodgkin lymphoma, but the recent finding of an inverse association between routine regular-strength aspirin use and Hodgkin lymphoma risk suggests that aspirin may protect against Hodgkin lymphoma development. To further investigate this association using prospectively collected data, we conducted a population-based case-control study in northern Denmark. A total of 478 incident Hodgkin lymphoma cases were identified in nationwide health-care databases from 1991 to 2008. Ten population controls were matched to each case on age, sex, and county using risk-set sampling. Use of aspirin, selective cyclooxygenase-2 inhibitors, and other nonsteroidal anti-inflammatory drugs (NSAIDs) from 1989 to 2007 was ascertained by linkage to a population-based prescription database. Conditional logistic regression was used to estimate odds ratios for associations between medication use and risk of Hodgkin lymphoma. The odds ratio (95% confidence interval) for ever use (>2 prescriptions) compared with never/rare use (< or =2 prescriptions) of low-dose aspirin was 0.7 (0.5-1.2). The association with low-dose aspirin use did not vary appreciably by recentness, duration, or intensity of use. Recent use (>2 prescriptions in the 1-2 years before the index date), short-term use (<7 years), and medium/high-intensity use (> or =25% of duration of use covered by prescription) of selective cyclooxygenase-2 inhibitors or other NSAIDs was associated with increased Hodgkin lymphoma risk possibly due to prodromal symptoms among cases. In conclusion, our results provide some evidence of a protective effect of low-dose aspirin, but not other NSAIDs, against Hodgkin lymphoma development.

Lymphocyte-rich classical Hodgkin's lymphoma: distinctive tumor and microenvironment markers

The existence, diagnostic features, and the biological and clinical relevance of lymphocyte-rich classical Hodgkin's lymphoma remain controversial. A comparative marker analysis of lymphocyte-rich classical Hodgkin's lymphoma, nodular lymphocyte-predominance Hodgkin's lymphoma, and of other subtypes of classical Hodgkin's lymphoma was carried out. Markers were selected focusing on B-cell lineage and transcription program (OCT.1, OCT.2, BOB.1, BCL6, PAX-5, GCET1, KLHL6, and BLIMP1), the NF-kappaB signaling pathway (REL-B, C-REL, TRAF-1, p-50, and MUM-1) and the T-cell microenvironment (CD3, CD57, PD-1, CXCL-13, and CD10, BCL-6, CD23). Lymphocyte-rich classical Hodgkin's lymphoma cases displayed features intermediate between those of classical Hodgkin's lymphoma and nodular lymphocyte-predominance Hodgkin's lymphoma. The expression of B-cell transcription factors such as OCT.1, OCT.2, BOB.1, and BCL6 was more frequent in lymphocyte-rich classical Hodgkin's lymphoma than in classical Hodgkin's lymphoma. A follicular T-cell microenvironment was also identified in 50% of lymphocyte-rich classical Hodgkin's lymphoma cases. NF-kB markers were expressed at frequencies comparable with those observed in classical Hodgkin's lymphoma. The neoplastic cell immunophenotype and microenvironment in lymphocyte-rich classical Hodgkin's lymphoma closely mimic that which are observed in the outer zone of the germinal center, where B-cell blasts with germinal-center markers co-express CD30 and the B-cell transcription program, surrounded by follicular T-cell rosettes. Lymphocyte-rich classical Hodgkin's lymphoma seems to be characterized by a stronger expression of the B-cell transcription program by the neoplastic cells and by a follicular T-cell background, occupying an intermediate position between classical Hodgkin's lymphoma and nodular lymphocyte-predominance Hodgkin's lymphoma.

Single agent bortezomib in the treatment of relapsed and refractory Hodgkin lymphoma: Cancer and leukemia Group B protocol 50206

Constitutive activation of nuclear factor-kappaB (NF-kappaB) has been described in patient-derived Reed - Sternberg cells and Hodgkin lymphoma (HL) cell lines and contributes to the proliferation and survival of HL. Therapeutic inhibition of the proteasome with bortezomib may inhibit over-expression of nuclear NF-kappaB by preventing degradation of IkappaB, which sequesters NF-kappaB in the cytoplasm. To evaluate this hypothesis, the Cancer and Leukemia Group B (CALGB) conducted a multi-institutional phase II trial of single agent bortezomib in patients with relapsed or refractory classical HL. Thirty patients received bortezomib 1.3 mg/m(2) on days 1, 4, 8, 11 and every 21 days for a median of 2 cycles (range, 1 - 8). Patients were heavily pre-treated with a median of four prior therapies, and 83% were previously transplanted. No responses were observed, 9 patients had stable disease, and 21 progressed. The median progression-free and overall survivals were 1.4 months [95% CI, (1.28, 1.91)] and 14.8 months [95% CI (11.2, 22.3)], respectively. Grade 3 - 4 adverse events, primarily thrombocytopenia, occurred in 15 patients. Therefore, although well tolerated, 1.3 mg/m(2) bortezomib administered biweekly has no single agent activity in relapsed/refractory classical HL.

B-cell differentiation immunophenotypes in classical Hodgkin lymphomas

The bcl6/CD10/MUM1/CD138 B-cell differentiation immunophenotypes were analysed in 101 cases of classical Hodgkin lymphomas (cHL) aiming to elucidate their histogenesis. Three major bcl6/CD10/MUM1/CD138 immunophenotypes were distinguished on the basis of the immunohistochemical positivity of Hodgkin and Reed-Sternberg (H/RS) cells: (a) the late germinal center (GC)/early post-GC B-cell-like immunophenotype (bcl6-/CD10-/MUM1+/CD138-); 59/101 cases (59%), (b) the post-GC B-cell-like immunophenotype (bcl6-/CD10-/MUM1+/CD138+); 24/101 cases (24%) and (c) the indeterminate immunophenotype (bcl6+/CD10-/MUM1+/CD138-: 14 cases and bcl6+/CD10-/MUM1+/CD138+: four cases); 18/101 cases (18%). The above findings indicate that H/RS cells in most cHL display bcl6/CD10/MUM1/CD138 immunophenotypes consistent with late GC/early post-GC or post-GC B-cell differentiation. In addition, H/RS cells in a small fraction of cHL display indeterminate bcl6/CD10/MUM1/CD138 immunophenotypic profiles which are characterized by simultaneous expression of GC, late GC/early post-GC and post-GC B-cell differentiation proteins. These immunophenotypic profiles do not correspond to the differentiation immunophenotypes of normal B-cells and their identification in a part of cHL suggests that the differentiation process of H/RS cells is not complete in a fraction of these cells and/or is still ongoing at the time of observation.

Genetic markers of mediastinal tumors

Determination of the genetic markers by the application of new genomic methodologies has provided important insight into the pathogenesis of mediastinal disease. These new techniques have enabled scientists to uncover differential gene expression patterns between subtypes of thymomas, correlate tumor marker expression with germ cell tumors, and determine a link between the NF-kappaB and JAK/STAT pathways with Hodgkin's and non-Hodgkin's lymphoma. Despite the progress made in the understanding of genetic markers of select mediastinal tumors, significantly more investigation is required to elucidate the molecular pathways involved in the pathogenesis of these tumors.

Polymorphic variation in NFKB1 and other aspirin-related genes and risk of Hodgkin lymphoma

We found that regular use of aspirin may reduce the risk of Hodgkin lymphoma (HL), a common cancer of adolescents and young adults in the United States. To explore possible biological mechanisms underlying this association, we investigated whether polymorphic variation in genes involved in nuclear factor-kappaB (NF-kappaB) activation and inhibition, other inflammatory pathways, and aspirin metabolism influences HL risk. Twenty single nucleotide polymorphisms (SNP) in seven genes were genotyped in DNA from 473 classical HL cases and 373 controls enrolled between 1997 and 2000 in a population-based case-control study in the Boston, Massachusetts, metropolitan area and the state of Connecticut. We selected target genes and SNPs primarily using a candidate-SNP approach and estimated haplotypes using the expectation-maximization algorithm. We used multivariable logistic regression to estimate odds ratios (OR) for associations with HL risk. HL risk was significantly associated with rs1585215 in NFKB1 (AG versus AA: OR, 2.1; 95% confidence interval, 1.5-2.9; GG versus AA: OR, 3.5; 95% confidence interval, 2.2-5.7, Ptrend=1.7x10(-8)) and with NFKB1 haplotypes (Pglobal=6.0x10(-21)). Similar associations were apparent across categories of age, sex, tumor EBV status, tumor histology, and regular aspirin use, although statistical power was limited for stratified analyses. Nominally significant associations with HL risk were detected for SNPs in NFKBIA and CYP2C9. HL risk was not associated with SNPs in IKKA/CHUK, PTGS2/COX2, UDP1A6, or LTC4S. In conclusion, genetic variation in the NF-kappaB pathway seems to influence risk of HL. Pooled studies are needed to detect any heterogeneity in the association with NF-kappaB across HL subgroups, including aspirin users and nonusers.

Biologic features of Hodgkin lymphoma and the development of biologic prognostic factors in Hodgkin lymphoma: tumor and microenvironment

Classical Hodgkin lymphoma is now recognised as a B-cell lymphoma. Improved therapy has increased cure rates dramatically; however, relapse and death still occurs in a minority of patients. Much has been learned about the biology of Hodgkin and Reed Sternberg cells and their interactions with the microenvironment, which has informed studies exploring biologic markers that may improve upon clinical prognostic models. This manuscript reviews recent advances in our understanding of the pathobiology of cHL with an emphasis on biologic prognostic markers.

Origin and pathogenesis of nodular lymphocyte-predominant Hodgkin lymphoma as revealed by global gene expression analysis

The pathogenesis of nodular lymphocyte–predominant Hodgkin lymphoma (NLPHL) and its relationship to other lymphomas are largely unknown. This is partly because of the technical challenge of analyzing its rare neoplastic lymphocytic and histiocytic (L&H) cells, which are dispersed in an abundant nonneoplastic cellular microenvironment. We performed a genome-wide expression study of microdissected L&H lymphoma cells in comparison to normal and other malignant B cells that indicated a relationship of L&H cells to and/or that they originate from germinal center B cells at the transition to memory B cells. L&H cells show a surprisingly high similarity to the tumor cells of T cell–rich B cell lymphoma and classical Hodgkin lymphoma, a partial loss of their B cell phenotype, and deregulation of many apoptosis regulators and putative oncogenes. Importantly, L&H cells are characterized by constitutive nuclear factor κB activity and aberrant extracellular signal-regulated kinase signaling. Thus, these findings shed new light on the nature of L&H cells, reveal several novel pathogenetic mechanisms in NLPHL, and may help in differential diagnosis and lead to novel therapeutic strategies.

The role of NF-kappaB in lymphoid malignancies

Nuclear Factor kappaB (NF-kappaB) transcription factors are central regulators of lymphocyte proliferation, survival and development. Although normally subject to tight control, constitutive activation of NF-kappaB promotes inappropriate lymphocyte survival and proliferation, and is recognised as key pathological feature in various lymphoid malignancies. Inhibition of NF-kappaB may be an attractive therapeutic approach in these diseases. This review focuses on the mechanisms and functional consequences of NF-kappaB activation in lymphoid malignancies and potential therapeutic strategies for inhibition of NF-kappaB.

Nuclear factor-kappaB activation and differential expression of survivin and Bcl-2 in human grade 2-4 astrocytomas

BACKGROUND

Antiapoptotis resulting from hyperactivation of the transcription factor NF-kappaB has been described in several cancer types. It is triggered by the interaction of the tumor necrosis factor (TNF) with its receptors and recruitment of the intermediate factor TNF-receptor associated factor (TRAF) 2. The NF-kappaB transcriptional activity could amplify the expression of antiapoptotic genes. The authors investigated the activity of NF-kappaB, and the mRNA expression of TNFalpha, TNFalpha receptor, TRAF1, TRAF2, and TRAF-associated NF-kappaB activator (TANK), and the antiapoptotic genes Bcl-2, c-IAP 1 and 2, and Survivin in human astrocytic tumors.

METHODS

Eight low-grade astrocytomas (LGA), 10 anaplastic astrocytomas (AAs), 10 glioblastoma multiforme (GBM) samples were used; 4 samples of normal brain tissue were used as controls. The NF-kappaB activation was analyzed by electrophoretic mobility shift assay; TRAF1, TRAF2, TANK/I-TRAF, Bcl-2, c-IAP 1 and 2, and Survivin mRNA expressions were studied using real-time quantitative reverse-transcriptase polymerase chain reaction.

RESULTS

NF-kappaB hyperactivity was detected in tumor samples. mRNA of antiapoptotic genes, particularly BCL-2 and Survivin, was hyperexpressed in gliomas. Interestingly, BCL-2 was hyperexpressed in LGAs, whereas a very high level of Survivin featured high-grade gliomas. The differential expression of antiapoptotic genes yielded a tight clustering of all LGA and nearly all GBM samples in cluster analysis.

CONCLUSIONS

NF-kappaB and factors involved in its intracellular activation were up-regulated in gliomas. NF-kappaB-activated antiapoptotic genes were hyperexpressed in tumor samples, but showed a differential expression with higher levels of Bcl-2 in LGAs and higher levels of Survivin in GBMs.

Bortezomib induces caspase-dependent apoptosis in Hodgkin lymphoma cell lines and is associated with reduced c-FLIP expression: A gene expression profiling study with implications for potential combination therapies

The Hodgkin cells and Reed-Sternberg cells (HRS) of classical Hodgkin lymphoma (CHL) are derived from germinal center B cells. The pathogenesis of CHL is unclear but constitutive activation of NFkappaB may contribute. Proteasome inhibition aimed at inhibiting NFkappaB has been shown to result in apoptosis in HRS cells. Here we investigated the effects of bortezomib, a proteasome inhibitor, in HRS cells with a combination of functional assays and gene expression profiling (GEP). Exposure of KMH2 and L428 cells to bortezomib resulted in inhibition of proliferation and induction of apoptosis. Gene expression analysis of KMH2 cells by oligonucleotide cDNA microarrays showed that a limited set of genes were differentially expressed involving several key cellular pathways including cell cycle and apoptosis. Among them, the caspase 8 inhibitor cFLIP was down-regulated and confirmed by Q-PCR. Given the evidence that cFLIP in HRS cells contribute to cells' insensitive to death receptor-mediated apoptosis, we combined bortezomib and TRAIL. This combination caused further down-regulation of cFLIP protein and increased apoptosis in CHL cells demonstrated by PARP p85 immunohistochemistry and immunoblotting. Such apoptotic effects were inhibited by caspase inhibitor z-VAD-FMK, confirming the pro-apoptotic effects of bortezomib and TRAIL are caspase-dependent. Bortezomib has no detectable effect on expression of TRAIL receptor DR4/DR5 in these two cell lines. Tissue microarray analysis of primary Hodgkin lymphomas displayed that 82% cases (95/116) expressed cFLIP in Reed-Sternberg cells. The discovery of apoptotic pathways that can be manipulated by proteasome inhibition provides rationale for the combination of bortezomib and agents such as TRAIL in CHL treatment.

IkappaBalpha independent induction of NF-kappaB and its inhibition by DHMEQ in Hodgkin/Reed-Sternberg cells

Constitutive nuclear factor kappaB (NF-kappaB) activation characterizes Hodgkin/Reed-Sternberg (H-RS) cells. Blocking constitutive NF-kappaB has been shown to be a potential strategy to treat Hodgkin lymphoma (HL). Here, for the first time we show that although constitutive NF-kappaB level of H-RS cell lines is very high, topoisomerase inhibitors further enhance NF-kappaB activation through IkappaB kinase activation in not only H-RS cell lines with wild-type IkappaBalpha, but also in those with IkappaBalpha mutations and lacking wild-type IkappaBalpha. Thus, both constitutive and inducible NF-kappaB are potential targets to treat HL. We also present the data that indicate the involvement of IkappaBbeta in NF-kappaB induction by topoisomerase inhibitors. A new NF-kappaB inhibitor, dehydroxymethylepoxyquinomicin (DHMEQ) inhibited constitutive NF-kappaB activity and induced apoptosis of H-RS cell lines. DHMEQ also inhibited the growth of H-RS cells without significant systemic toxicity in a NOD/SCID/gammac(null) (NOG) mice model. DHMEQ and topoisomerase inhibitors revealed enhancement of apoptosis of H-RS cells by blocking inducible NF-kappaB. Results of this study suggest that both constitutive and inducible NF-kappaB are molecular targets of DHMEQ in the treatment of HL. The results also indicate that IkappaBbeta is involved in NF-kappaB activation in H-RS cells and IkappaBbeta substitutes for IkappaBalpha in H-RS cells lacking wild-type IkappaBalpha.

Pathobiology of Classical Hodgkin Lymphoma

The World Health Organization has acknowledged the malignant nature of classical Hodgkin lymphoma (cHL), which encompasses four histological subtypes. The diagnosis of cHL is based on the detection of malignant Hodgkin and Reed-Sternberg cells (HRSC) confirmed by immunophenotyping and the detection of growth patterns specific to each histological subtype. The pathologic HRSC arise from germinal center or immediate postgerminal cells that lack detectable immunoglobulin/B-cell antigen receptor expression, with a consequent loss of B-cell identity; very few cHL cases are of T-cell origin. To escape apoptosis, which normally occurs in B cells with nonfunctioning antigen receptor machinery, HRSC develop concurrent antiapoptotic mechanisms by activation of nuclear factor-kappaB or are rescued by Epstein-Barr virus infection. HRSC are characterized by a variable and inconstant immunophenotype, with a remarkable loss of lineage-specific cell antigens and expression of antigens of other cell lineages. The master plan of B-cell identity in HRSC is disturbed not only at the immunoglobulin expression level, but also at the transcriptional factor level. HRSC are further characterized by profound cell cycle deregulation with futile replication, multinucleation and poly- and aneuploidy. Here, we review pathobiological aspects of cHL with respect to lymphomagenesis and routine diagnostics.

Tobacco smoking, alcohol drinking and Hodgkin's lymphoma: a European multi-centre case-control study (EPILYMPH)

We analysed the effects of tobacco and alcohol in the aetiology of Hodgkin's lymphoma (HL), based on 340 cases and 2465 controls enrolled in Spain, France, Italy, Germany, Ireland and Czech Republic, between 1998 and 2004. Current smokers showed a significantly increased odds ratio (OR) of HL of 1.39 (95% confidence interval (CI) = 1.04-1.87). Analyses were also conducted separately for subjects younger than 35 years (179 cases) and for older subjects (161 cases). For subjects below age 35, no association was observed between tobacco and HL, whereas for older subjects, ever-smokers experienced a doubled risk of HL as compared to never smokers and the OR of HL for current smoking was 2.35 (95% CI = 1.52-3.61), with suggestion of a dose-response relationship. A protective effect of alcohol was observed in both age groups. The OR for ever-regular drinking was 0.58 (95% CI = 0.38-0.89) for younger subjects and 0.50 (95% CI = 0.34-0.74) for older subjects. There was no evidence of interaction between tobacco and alcohol. Our results are consistent with previous studies, suggesting a protective effect of alcohol on HL. An effect of tobacco was suggested for HL occurring in middle and late age, although this finding might have occurred by chance.

Minimal change nephrotic syndrome and classical Hodgkin's lymphoma: Report of 21 cases and review of the literature

Minimal change nephrotic syndrome (MCNS) is described as a paraneoplastic manifestation of classical Hodgkin's lymphoma (cHL). We reassessed the pathophysiological and clinical significance of this association. A retrospective study was performed to evaluate a cohort of adult patients who developed MCNS and cHL. Twenty-one patients recruited in 15 French centers were analyzed. cHL was associated with inflammatory and general symptoms in most cases. The morphological subtype was predominantly nodular sclerosis (71.4%). MCNS appeared before the diagnosis of lymphoma in eight patients (38.1%) and in this case, it was characterized by a nephrotic syndrome (NS) frequently resistant (50%) or dependent (12.5%) to steroid treatment. Interestingly, diagnosis (3-120 months after MCNS) and effective treatment of the hemopathy were associated with the disappearance of the MCNS. cHL was diagnosed before MCNS in nine patients (42.9%), and in this case, glomerulopathy was associated with cHL relapse in 55.5% of cases. In four patients (19%), the two diseases occurred simultaneously. Extensive immunohistochemical study of lymph nodes was performed in eight patients and did not reveal particular features. In conclusion, MCNS associated with cHL is frequently dependent or resistant to steroid regimen, but remission of NS is obtained with the cure of lymphoma.

Cadmium-Induced Apoptosis in Rat Kidney Epithelial Cells Involves Decrease in Nuclear Factor-Kappa B Activity

Renal epithelial cells undergo apoptosis upon exposure to cadmium (Cd). Transcription factors, such as nuclear factor-kappa B (NF-kappaB), mediate the expression of a number of genes involved in apoptosis. The present study was designed to examine the involvement of this transcription factor in Cd-induced apoptosis. Rat kidney proximal tubular epithelial cells, NRK-52E, were incubated with up to 20 microM CdCl2 in serum-free medium for 5 h followed by incubation in serum-containing medium (without Cd) for an additional 12 h. The cells accumulated 582 +/- 19 ng Cd/mg protein after 5-h exposure to 20 microM Cd. As a result of Cd exposure, the DNA-binding activity of the p65 subunit of NF-kappaB was decreased in a concentration- and time-dependent manner. The activity of tumor necrosis factor-alpha-induced inhibitor of kappa B (IkappaB) kinase alpha was also inhibited by Cd. In addition, the phosphorylation of IkappaB-alpha and NF-kappaB p65, as well as the levels of NF-kappaB target gene products, cIAP-1 and cIAP-2, were reduced. Pretreatment of the cells with the antioxidant U83836E or butylated hydroxytoluene preserved the DNA-binding activity and blocked the Cd-induced decease in IkappaB-alpha phosphorylation. Cd exposure caused the activation of caspase-3, -7, and -9 and DNA fragmentation. By flow cytometry, 14.6 and 30.5% apoptosis was detected at 6 and 12 h after stopping the Cd exposure. Overexpression of NF-kappaB p65 by transient transfection protected the cells from the Cd-induced apoptosis. Conversely, attenuation of NF-kappaB activity by pretreatment with SN50, an NF-kappaB nuclear translocation inhibitor, potentiated apoptosis. These results suggest that Cd-induced apoptosis involves suppression of NF-kappaB activity which may be mediated by oxidative stress.

Tumor necrosis factor- $$\alpha$$ induces caspase-independent cell death in human neutrophils via reactive oxidants and associated with calpain activity

Apoptosis mediated by caspase activation is important in the neutrophil homeostasis and resolution of tissue inflammation. Paradoxically, our previous study demonstrated that broad-spectrum caspase inhibition augmented tumor necrosis factor (TNF)-alpha-induced cell death in the human neutrophils. Therefore, we further explored the mechanisms related to the caspase-independent cell death in the neutrophils. The cell apoptosis/necrosis was determined by annexin V and propidium iodide dual staining in flow cytometry. Their morphological changes were observed under light microscopy. Fluorogenic substrates were used to measure the intracellular oxidative reactions and the activities of proteinases, calpains. Calpain inhibitors and antioxidants were used to elucidate the relationship of calpains and oxidants with the neutrophil cell death. Our results verified the caspase-independent cell death pathway in the zVAD-sensitized, TNF-alpha-stimulated neutrophils. Furthermore, the cell death was accompanied with increased calpain and oxidative activities in the cells. Calpain inhibitors, zLLY, as well as anti-oxidants, catalase and DMSO, were able to attenuate the cell death in the zVAD-sensitized, TNF-alpha-induced neutrophils. Pretreating the neutrophils with G-CSF or GM-CSF was not able to reduce the cell death. These results demonstrate that, in human neutrophils, TNF-alpha-induces a caspase-independent cell death signal, which is related to calpain and oxidative activities and cannot be rescued by the growth factor-related signaling mechanism.

Expression of the tumor necrosis factor receptor-associated factors 1 and 2 and regulation of the nuclear factor-kappaB antiapoptotic activity in human gliomas

OBJECT

Tumor necrosis factor receptor (TNFR)-associated factors (TRAFs) are a recently established group of proteins involved in the intracellular signaling of the TNFR superfamily members. The TRAFs have been implicated in promoting cell survival through the activation of transcription factor nuclear factor (NF)-kappaB. The authors investigated the expression of NF-kappaB, caspase 3, TRAF1, TRAF2, and TRAF-associated NF-kappaB activator/TRAF-interacting protein (TANK/I-TRAF), a regulator of TRAF activity, in human gliomas.

METHODS

Tumor samples were obtained in 27 adult patients harboring seven low-grade gliomas, nine anaplastic astrocytomas, and 11 glioblastomas multiforme. The NF-kappaB activation was analyzed using the electrophoresis mobility shift assay; TRAF1, TRAF2, TANK/I-TRAF, and caspase 3 expression were studied using Western blot analysis. Upregulated NF-kappaB DNA-binding activity, compared with that in normal brain tissue, was detected in all tumor samples (p = 0.002). The level of NF-kappaB activity showed some correlation with World Health Organization tumor grades (p = 0.01), even though variable activity levels were demonstrated in relation to tissue heterogeneity, which resulted in a substantial number of outliers in the quantitative analysis. Increased levels of TRAF1, TRAF2, and TANK/ I-TRAF were expressed in astrocytomas compared with levels in normal brain tissue (p = 0.02, 0.006, and 0.01, respectively).

CONCLUSIONS

Data in this study confirm the upregulation of NF-kappaB in gliomas and reveal a correlation between levels of this transcription factor and tumor grade. A constitutive expression of TRAF1, TRAF2, and TANK/I-TRAF in human gliomas was documented. These proteins are involved in the intracellular signal transduction of the TNFR superfamily and in the control of NF-kappaB expression and its antiapoptotic activity.

Bortezomib interactions with chemotherapy agents in acute leukemia in vitro

Although there is effective chemotherapy for many patients with leukemia, 20% of children and up to 65% of adults relapse. Novel therapies are needed to treat these patients. Leukemia cells are very sensitive to the proteasome inhibitor bortezomib (VELCADE(R), PS-341), which enhances the in vitro cytotoxic effects of dexamethasone and doxorubicin in multiple myeloma. To determine if bortezomib enhances the cytotoxicity of agents used in leukemia, we employed an in vitro tetrazolium-based colorimetric assay (MTT) to evaluate the cytotoxic effects of bortezomib alone and in combination with dexamethasone, vincristine, doxorubicin, cytarabine, asparaginase, geldanamycin, trichostatin A, and the bcl-2 inhibitor HA14.1. We demonstrated that primary leukemia lymphoblasts and leukemia cell lines are sensitive to bortezomib, with an average IC(50) of 12 nM. Qualitative and quantitative bortezomib-drug interactions were evaluated using the universal response surface approach (URSA). Bortezomib was synergistic with dexamethasone in dexamethasone-sensitive leukemia cells, and additive with vincristine, asparaginase, cytarabine, and doxorubicin. The anti-leukemic activity of bortezomib was also additive with geldanamycin and HA14.1, and additive or synergistic with trichostatin A. These results were compared to analysis using the median-dose effect method, which generated complex drug interactions due to differences in dose-response curve sigmoidicities. These data suggest bortezomib could potentiate the cytotoxic effects of combination chemotherapy in patients with leukemia.

The fully human anti-CD30 antibody 5F11 activates NF-κB and sensitizes lymphoma cells to bortezomib-induced apoptosis

5F11, a fully human monoclonal antibody directed against CD30, effectively induces killing of CD30-expressing lymphoma cell lines in vitro and in animal models. A recently conducted phase 1/2 study shows that 5F11 is well tolerated in heavily pretreated patients with relapsed and refractory CD30+ lymphoma and has some clinical activity. In the present study, we demonstrate that 5F11 activates nuclear factor κB (NF-κB) and the anti-apoptotic protein cellular FLICE (Fas-associating protein with death domain-like interleukin-1β-converting enzyme) inhibitory protein (c-flip) in Hodgkin lymphoma (HD)-derived cell lines, which might cause apoptosis resistance, thus limiting the clinical use of 5F11. To overcome this resistance, we combined 5F11 with the proteasome inhibitor bortezomib, which has been shown to suppress NF-κB activity. This combination revealed a synergistic cytotoxic effect in vitro and in a human HD xenograft model provided that 5F11 precedes bortezomib treatment. We conclude that initial 5F11-mediated NF-κB signaling sensitizes the tumor cells to bortezomib-induced cell death. These data suggest a therapeutic value of this combination for HD patients. (Blood. 2005;106:1839-1842)

A beginner's guide to NF-kappaB signaling pathways

Nuclear factor kappaB (NF-kappaB) belongs to a family of heterodimeric transcription factors that play a key role in inflammatory and stress responses as well as in tumor cell resistance to apoptosis. These effects are due to the NF-kappaB-dependent transcription of many proinflammatory and antiapoptotic genes, whose products ensure various cell responses to environmental conditions. The signal transduction pathways leading to NF-kappaB activation are well characterized, and the different steps implicated in these pathways involve proteins that could constitute targets for NF-kappaB inhibition. Several inhibitors aiming to prevent NF-kappaB activity and thus the transcription of target genes are studied, and a few compounds seem particularly promising. We try here to summarize the advantages that can issue from various studies on NF-kappaB.

From Hodgkin disease to Hodgkin lymphoma: biologic insights and therapeutic potential

Reclassification of Hodgkin disease as Hodgkin lymphoma (HL) represents a milestone in the lymphoma field, awarding recent insights in the molecular biology of Hodgkin and Reed-Sternberg (H-RS) cells and their environment. This review summarizes antiapoptotic and proproliferative pathways involved in the pathogenesis of this disease with the ultimate goal of translating laboratory knowledge into clinical decision making. The focus is on potential targets and novel drugs, which are discussed in the context of the complex biology of HL. Considering that HL patients are more likely to die from acute and late treatment-related toxicities than from HL itself, the introduction of targeted, biologically based therapies for HL patients with palliative and eventually curative intention might be justified. (Blood. 2005;105:4553-4560)

TRAF1 Expression and c-Rel Activation Are Useful Adjuncts in Distinguishing Classical Hodgkin Lymphoma From a Subset of Morphologically or Immunophenotypically Similar Lymphomas

We demonstrate that the expression of TRAF1 and activated c-Rel, two proteins that function in signaling events downstream of activated CD30 in Reed-Sternberg cells, reliably distinguish classical Hodgkin lymphoma from anaplastic large cell lymphoma, nodular lymphocyte predominant Hodgkin lymphoma, and nonmediastinal diffuse large B-cell lymphoma. By immunohistochemistry, we found strong TRAF1 staining in 21 of 25 cases of classical Hodgkin lymphoma. In contrast, strong TRAF1 staining was present in only 1 of 17 cases of anaplastic large cell lymphoma, 0 of 15 cases of lymphocyte predominant Hodgkin lymphoma, and 2 of 36 cases of nonmediastinal diffuse large B-cell lymphoma. Nuclear staining for c-Rel, a pattern consistent with NFkappaB activation, was observed in the Reed-Sternberg cells in 23 of 25 cases of classical Hodgkin lymphoma but only in 1 of 15 cases of anaplastic large cell lymphoma and 3 of 15 cases of nodular lymphocyte predominant Hodgkin lymphoma. A heterogeneous pattern of subcellular c-Rel localization was found in nonmediastinal diffuse large B-cell lymphoma. Taken together, the combination of strong cytoplasmic TRAF1 expression and nuclear c-Rel was present in 80% of cases of classical Hodgkin lymphoma (n = 25) but in only 3% of cases of the other malignant lymphomas tested (n = 62). Thus, the differential expression patterns of downstream components in the CD30 signaling pathway may prove a useful adjunct in distinguishing cases of classical Hodgkin lymphoma from other malignant lymphomas in routine clinical practice.