CD30 in normal and neoplastic cells

Sézary Syndrome and Atopic Dermatitis: Comparison of Immunological Aspects and Targets

Sézary syndrome (SS), an aggressive form of erythrodermic pruritic cutaneous T cell lymphoma (CTCL), from an immunological perspective characterized by increased Th2 cytokine levels, elevated serum IgE and impaired cellular immunity. Not only the clinical appearance but also the hallmark immunological characteristics of SS often share striking similarities with acute flares of atopic dermatitis (AD), a common benign chronic inflammatory skin disease. Given the overlap of several immunological features, the application of similar or even identical therapeutic approaches in certain stages of both diseases may come into consideration. The aim of this review is to compare currently accepted immunological aspects and possible therapeutic targets in AD and SS.

Brentuximab: a major advance in treatment of CD30-positive malignancies

Antibody-directed therapies allow greater selectivity in targeting of tumor associated antigens and spare normal cells. Brentuximab vedotin is an anti-CD30 antibody–drug conjugate. It has demonstrated impressive activity in the treatment of refractory and or relapsed Hodgkin's lymphoma, anaplastic large cell lymphoma and other CD30+ lymphoid malignancies. Several ongoing trials are testing the potential use of brentuximab vedotin for treatment of various CD30+ and CD30- malignancies in the setting of high-risk untreated disease. It is being tested in combination with chemotherapy, and testing in combination with immune therapy is also planned. CD30 plays a pivotal role in immune regulation and is also an attractive new target for intervention in the setting of select auto-immune diseases, as well as graft versus host disease.

The European Medicines Agency Review of Brentuximab Vedotin (Adcetris) for the Treatment of Adult Patients With Relapsed or Refractory CD30+ Hodgkin Lymphoma or Systemic Anaplastic Large Cell Lymphoma: Summary of the Scientific Assessment of the Committee for Medicinal Products for Human Use

BACKGROUND

On October 25, 2012, a conditional marketing authorization valid throughout the European Union (EU) was issued for brentuximab vedotin for the treatment of adult patients with relapsed or refractory CD30+ Hodgkin lymphoma (HL) and for the treatment of adult patients with relapsed or refractory systemic anaplastic large cell lymphoma (sALCL). For HL, the indication is restricted to treatment after autologous stem cell transplantation (ASCT) or after at least two previous therapies when ASCT or multiagent chemotherapy is not a treatment option.

MATERIALS AND METHODS

Brentuximab vedotin is an antibody-drug conjugate (ADC) composed of a CD30-directed monoclonal antibody (recombinant chimeric IgG1) that is covalently linked to the antimicrotubule agent monomethyl auristatin E (MMAE). Binding of the ADC to CD30 on the cell surface initiates internalization of the MMAE-CD30 complex, followed by proteolytic cleavage that releases MMAE. The recommended dose is 1.8 mg/kg administered as an intravenous infusion over 30 minutes every 3 weeks.

RESULTS

Brentuximab vedotin as a single agent was evaluated in two single-arm studies. Study SG035-003 included 102 patients with relapsed or refractory HL. An objective response was observed in 76 patients (75%), with complete remission in 34 (33%). Study SG035-004 included 58 patients with relapsed or refractory sALCL. An objective response was observed in 50 patients (86%), with complete remission in 34 (59%). The most frequently observed toxicities were peripheral sensory neuropathy, fatigue, nausea, diarrhea, neutropenia, vomiting, pyrexia, and upper respiratory tract infection.

CONCLUSION

The present report summarizes the scientific review of the application leading to approval in the EU. The detailed scientific assessment report and product information, including the summary of the product characteristics, are available on the European Medicines Agency website (http://www.ema.europa.eu).

IMPLICATIONS FOR PRACTICE

Brentuximab vedotin was approved in the European Union for the treatment of adult patients with relapsed or refractory CD30+ Hodgkin lymphoma or systemic anaplastic large cell lymphoma. For Hodgkin lymphoma, brentuximab vedotin should only be used after autologous stem cell transplantation or following at least two prior therapies when transplantation or multiagent chemotherapy is not a treatment option. In two studies involving 160 patients, partial or complete responses were observed in the majority of patients. Although there was no information on the survival of patients treated in the studies at the time of approval, the responses were considered a clinically relevant benefit.

Immuno-PET Imaging of CD30-Positive Lymphoma Using 89Zr-Desferrioxamine-Labeled CD30-Specific AC-10 Antibody

The CD30-specific antibody-drug conjugate, brentuximab vedotin, is approved for the treatment of relapsed, refractory Hodgkin lymphomas and systemic anaplastic large T-cell lymphomas. Multiple ongoing clinical trials are investigating brentuximab vedotin efficacy in other CD30-positive hematologic malignancies. Because CD30 expression varies among different types of lymphoma and can also change during the course of treatment, companion diagnostic imaging of CD30 could be a valuable tool in optimizing patient-specific brentuximab vedotin treatment regimens.

METHODS

The mouse antihuman CD30 antibody AC-10 was radiolabeled with the positron-emitting radionuclide (89)Zr. The stability and specificity of (89)Zr-desferrioxamine (DFO)-labeled CD30-specific AC-10 antibody ((89)Zr-DFO-AC-10) was evaluated in vitro. The pharmacokinetics of (89)Zr-DFO-AC-10 was studied in BALB/c nude mice bearing subcutaneous human Karpas 299 tumors (CD30-positive model) or A-431 tumors (CD30-negative model) using PET/CT imaging, biodistribution studies, and autoradiography.

RESULTS

AC-10 was conjugated with a DFO B chelator and radiolabeled with (89)Zr to give formulated (89)Zr-DFO-AC-10 with a radiochemical yield of 80%, radiochemical purity greater than 99%, and specific activity of 111-148 MBq/mg. (89)Zr-DFO-AC-10 was stable in mouse and human sera and preserved the immunoreactivity toward CD30. Biodistribution data showed the highest tissue accumulation of (89)Zr-DFO-AC-10 in CD30-positive tumors, with 37.9% ± 8.2% injected activity per gram of tissue at 72 h after injection, whereas uptake in CD30-negative tumors was 11.0% ± 0.4%. The specificity of (89)Zr-DFO-AC-10 binding to CD30 in vivo was confirmed by blocking studies. Time-activity curves showed that between 24 and 144 h after injection, tumor-to-muscle ratios increased from 18.9 to 51.8 in the CD30-positive model and from 4.8 to 8.7 in the CD30-negative model. Tumor-to-blood ratios also increased, from 3.2 to 13.6 and from 1 to 2 in the CD30-positive and -negative models, respectively.

CONCLUSION

Our results demonstrate that for measuring CD30 expression, (89)Zr-DFO-AC-10 is a sensitive PET agent with high tumor-to-normal-tissue contrast. (89)Zr-DFO-AC-10 is a promising CD30-imaging radiotracer for clinical translation in patients with various lymphomas and other diseases.

Identification of the Ki-1 antigen (CD30) as a novel therapeutic target in systemic mastocytosis

The Ki-1 antigen (CD30) is an established therapeutic target in patients with Hodgkin lymphoma and anaplastic large-cell lymphoma. We have recently shown that CD30 is expressed abundantly in the cytoplasm of neoplastic mast cells (MCs) in patients with advanced systemic mastocytosis (SM). In the current study, we asked whether CD30 is expressed on the surface of neoplastic MCs in advanced SM, and whether this surface structure may serve as therapeutic target in SM. As assessed by flow cytometry, CD30 was found to be expressed on the surface of neoplastic MCs in 3 of 25 patients (12%) with indolent SM, 4 of 7 patients (57%) with aggressive SM, and 4 of 7 patients (57%) with MC leukemia. The immature RAS-transformed human MC line MCPV-1.1 also expressed cell surface CD30, whereas the KIT-transformed MC line HMC-1.2 expressed no detectable CD30. The CD30-targeting antibody-conjugate brentuximab-vedotin inhibited proliferation in neoplastic MCs, with lower IC50 values obtained in CD30(+) MCPV-1.1 cells (10 µg/mL) compared with CD30(-) HMC-1.2 cells (>50 µg/mL). In addition, brentuximab-vedotin suppressed the engraftment of MCPV-1.1 cells in NSG mice. Moreover, brentuximab-vedotin produced apoptosis in all CD30(+) MC lines tested as well as in primary neoplastic MCs in patients with CD30(+) SM, but did not induce apoptosis in neoplastic MCs in patients with CD30(-) SM. Furthermore, brentuximab-vedotin was found to downregulate anti-IgE-induced histamine release in CD30(+) MCs. Finally, brentuximab-vedotin and the KIT D816V-targeting drug PKC412 produced synergistic growth-inhibitory effects in MCPV-1.1 cells. Together, CD30 is a promising new drug target for patients with CD30(+) advanced SM.

CD30 cell graphs of Hodgkin lymphoma are not scale-free--an image analysis approach

MOTIVATION

Hodgkin lymphoma (HL) is a type of B-cell lymphoma. To diagnose the subtypes, biopsies are taken and immunostained. The slides are scanned to produce high-resolution digital whole slide images (WSI). Pathologists manually inspect the spatial distribution of cells, but little is known on the statistical properties of cell distributions in WSIs. Such properties would give valuable information for the construction of theoretical models that describe the invasion of malignant cells in the lymph node and the intercellular interactions.

RESULTS

In this work, we define and discuss HL cell graphs. We identify CD30(+) cells in HL WSIs, bringing together the fields of digital imaging and network analysis. We define special graphs based on the positions of the immunostained cells. We present an automatic analysis of complete WSIs to determine significant morphological and immunohistochemical features of HL cells and their spatial distribution in the lymph node tissue under three different medical conditions: lymphadenitis (LA) and two types of HL. We analyze the vertex degree distributions of CD30 cell graphs and compare them to a null model. CD30 cell graphs show higher vertex degrees than expected by a random unit disk graph, suggesting clustering of the cells. We found that a gamma distribution is suitable to model the vertex degree distributions of CD30 cell graphs, meaning that they are not scale-free. Moreover, we compare the graphs for LA and two subtypes of HL. LA and classical HL showed different vertex degree distributions. The vertex degree distributions of the two HL subtypes NScHL and mixed cellularity HL (MXcHL) were similar.

AVAILABILITY AND IMPLEMENTATION

The CellProfiler pipeline used for cell detection is available at https://sourceforge.net/projects/cellgraphs/.

CONTACT

ina.koch@bioinformatik.uni-frankfurt.de

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Peripheral T-cell and NK cell lymphoproliferative disorders: cell of origin, clinical and pathological implications

T-cell lymphoproliferative disorders are a heterogeneous group of neoplasms with distinct clinical-biological properties. The normal cellular counterpart of these processes has been postulated based on functional and immunophenotypic analyses. However, T lymphocytes have been proven to be remarkably capable of modulating their properties, adapting their function in relationship with multiple stimuli and to the microenvironment. This impressive plasticity is determined by the equilibrium among a pool of transcription factors and by DNA chromatin regulators. It is now proven that the acquisition of specific genomic defects leads to the enforcement/activation of distinct pathways, which ultimately alter the preferential activation of defined regulators, forcing the neoplastic cells to acquire features and phenotypes distant from their original fate. Thus, dissecting the landscape of the genetic defects and their functional consequences in T-cell neoplasms is critical not only to pinpoint the origin of these tumors but also to define innovative mechanisms to re-adjust an unbalanced state to which the tumor cells have become addicted and make them vulnerable to therapies and targetable by the immune system. In our review, we briefly describe the pathological and clinical aspects of the T-cell lymphoma subtypes as well as NK-cell lymphomas and then focus on the current understanding of their pathogenesis and the implications on diagnosis and treatment.

CD30 expression in malignant vascular tumors and its diagnostic and clinical implications: a study of 146 cases

Angiosarcoma (AS) is a rare malignant vascular tumor, whereas epithelioid hemangioendothelioma (EHE) is a vascular tumor of low-grade malignancy. CD30 is a member of the tumor necrosis factor receptor superfamily, member 8 (TNFRSF8). Although the expression of CD30 is most commonly associated with lymphoid malignancies or germ cell tumors, occasional ASs have been reported as CD30 positive. However, there are limited data to evaluate its role definitively in malignant vascular tumors. In this study, we evaluated 91 ASs, 30 EHEs from various sites, and 25 Kaposi sarcomas. Overall, CD30 was expressed in 31/91 cases (34%) of AS, in 7/30 cases (30%) of EHE, but in none of the Kaposi sarcomas. CD30 was expressed in a membranous staining pattern and positivity in tumor cells varied from focal to diffuse. The positive ASs included vasoformative more differentiated tumors and also solid, undifferentiated, lymphoma-like examples, one of which was classified as lymphoma before the era of immunohistochemistry. The CD30 expression was seen in >50% of tumor cells in a majority of ASs but only in 7% of EHEs. None of the 55 ASs studied were immunohistochemically positive for TIA-1 or Granzyme B, antigens used as more specific markers for anaplastic large-cell lymphoma. Compared with AS, normal vascular endothelia of capillaries and muscular vessels showed variable positivity. Among hemangiomas, cavernous and spindle cell hemangiomas showed most frequent endothelial CD30 positivity, whereas in most other hemangiomas, CD30 positivity was scant. In conclusion, CD30 expression occurs in a significant subset of ASs and EHEs and needs to be included in the differential diagnosis with other CD30-positive malignancies to avoid a diagnostic pitfall. It remains to be determined whether patients with strongly CD30-positive ASs could be candidates for targeted therapy using the recently introduced CD30 antibody drug conjugates.

Effects of physiological and synthetic IAP antagonism on c-IAP-dependent signaling

Cellular inhibitor of apoptosis proteins 1 and 2 (c-IAP1/2) play central roles in signal transduction mediated by numerous receptors that participate in inflammatory and immune responses. In certain pathways, such as activation of NF-κB, their degradation is a major regulatory event and is physiologically induced by activation of receptors. Additionally, a number of synthetic compounds have been developed that also target the c-IAPs and induce their degradation. However, the extent of a synthetic IAP antagonist's ability to mirror the transcriptional program by a physiological signal remains unclear. Here we take a systems approach to compare the transcriptional programs triggered by activation of CD30, a well-characterized receptor previously shown to induce the degradation of the c-IAPs, to SM-164, a synthetic IAP antagonist that specifically triggers c-IAP degradation. Employing a technique that allows the specific analysis of newly transcribed RNA, we have generated comparative transcriptome profiles for CD30 activation and SM-164 treatment. Analysis of these profiles revealed that the genes regulated by each stimulus were not completely shared, indicating novel functions of IAP antagonists and consequences of c-IAP1/2 degradation. The data identified a role for c-IAP1/2 in the regulation of the ribosome and protein synthesis, which was subsequently confirmed by biological assays. These findings expand our knowledge of the roles of c-IAP1/2 in signaling and provide insight into the mechanism of synthetic IAP antagonists, furthering our understanding of their therapeutic potential.

Novel therapies for cutaneous T-cell lymphoma: what does the future hold?

INTRODUCTION

Cutaneous T-cell lymphomas (CTCLs) represent a group of extranodal non-Hodgkin lymphomas, of which mycosis fungoides (MF) is the most frequent. Standard therapeutic approaches are well established and often achieve stable disease. However, cure for MF is rare and thus novel therapies are needed.

AREAS COVERED

This review provides a discussion of the most promising new therapeutic approaches in the management of MF and other rare CTCLs. It includes targeted therapies with antibodies against surface molecules on malignant T cells (e.g., brentuximab), novel chemotherapeutic agents (e.g., pralatrexate), small-molecule compounds (e.g., panobinostat) and evidence of emerging targets in CTCLs (e.g., anti-IL-31). It also provides discussion of immune checkpoint inhibitors such as anti-PD1 that are worth considering in the treatment of leukaemic CTCL variants. Finally, it gives a brief overview of the possible use of stem-cell transplantation.

EXPERT OPINION

There is no doubt that progress has been made in the treatment of CTCLs with new, innovative and promising therapies approaching. However, there is still an urgent need to identify and test additional targets in well-designed clinical trials.

Biostable ssDNA aptamers specific for Hodgkin lymphoma

As a "chemical antibody", oligonucleotide aptamers can specifically bind to their target molecules. However, clinical potential of aptamers in disease diagnosis is not yet fully explored. Using a tumor cell-based selection protocol, we developed single-stranded DNA aptamers for Hodgkin lymphoma (HL) tumor cells. The aptamers specifically bound to HL cells with a high affinity, reaching maximal cell binding at 10 nM final concentration. Importantly, the aptamers were able to selectively detect HL cells and did not react to other tumor or blood cells in mixed samples, indicating that the aptamers can be used as a specific probe for in vitro analysis of HL cells. Moreover, due to the inherent properties of DNA, the aptamers were stable in human serum, suggesting potential for in vivo detection of HL tumor cells.

CD30 expression by bone marrow mast cells from different diagnostic variants of systemic mastocytosis

AIMS

CD30 expression by bone marrow (BM) mast cells (MC) has been reported recently in systemic mastocytosis (SM) patients. The aim of this study was to investigate the potential diagnostic and prognostic value of CD30 expression in SM as assessed by multiparameter flow cytometry.

METHODS AND RESULTS

A total of 163 consecutive BM samples corresponding to 142 SM patients and 21 non-mastocytosis cases were studied. CD30 was positive in most SM patients (80%), but in only one non-mastocytosis case (4.8%). When combined with CD25, CD30 contributed to an improved accuracy over that of CD25 alone (98% versus 93%) mainly because most (eight of nine) of the well-differentiated SM (WDSM), who lacked CD25, were CD30(+). Similar levels of expression of CD30 were observed among all different subgroups of SM except mast cell leukaemia; among indolent SM (ISM) patients, no significant association was observed between the levels of CD30 expression and other clinical and biological features of the disease.

CONCLUSIONS

The increased expression of CD30 associated with absence of CD25 contributes to the diagnosis of WDSM and its distinction from other subtypes of SM. By contrast, CD30 expression did not contribute either to prognostic stratification of ISM or to the differential diagnosis between ISM and aggressive SM cases.

New drugs and targeted treatments in Hodgkin's lymphoma

New drugs are being developed in recent years that may change the handling of relapsed and refractory Hodgkin's lymphoma patients. Brentuximab vedotin treatment has already been approved by the FDA; and other drugs are promising, such as histone deacetylase inhibitors, bendamustine, lenalidomide and m-TOR inhibitors.

Immunotherapy of CD30-expressing lymphoma using a highly stable ssDNA aptamer

CD30 is highly expressed on Hodgkins lymphoma and anaplastic large cell lymphoma, making it an attractive target for therapy. We describe the generation of serum-stabilized ssDNA aptamers that bind CD30 via a hybrid SELEX methodology. The selected aptamer bound CD30 with high affinity and specificity. Further optimization of the aptamer led to a short, truncated variant with a 50-fold higher affinity than its longer counterpart. The multivalent aptamer was able to induce oligomerization of CD30 receptors and, in effect, activate downstream signaling, which led to apoptosis of ALCL cells. Immunotherapy using aptamer-based co-stimulation provides an alternative to antibodies, and has potential to transform cancer treatment.

CD30 targeting with brentuximab vedotin: a novel therapeutic approach to primary effusion lymphoma

Primary effusion lymphoma (PEL) is an aggressive subtype of non-Hodgkin lymphoma characterized by short survival with current therapies, emphasizing the urgent need to develop new therapeutic approaches. Brentuximab vedotin (SGN-35) is an anti-CD30 monoclonal antibody (cAC10) conjugated by a protease-cleavable linker to a microtubule-disrupting agent, monomethyl auristatin E. Brentuximab vedotin is an effective treatment of relapsed CD30-expressing Classical Hodgkin and systemic anaplastic large cell lymphomas. Herein, we demonstrated that PEL cell lines and primary tumors express CD30 and thus may serve as potential targets for brentuximab vedotin therapy. In vitro treatment with brentuximab vedotin decreased cell proliferation, induced cell cycle arrest, and triggered apoptosis of PEL cell lines. Furthermore, in vivo brentuximab vedotin promoted tumor regression and prolonged survival of mice bearing previously reported UM-PEL-1 tumors as well as UM-PEL-3 tumors derived from a newly established and characterized Kaposi's sarcoma-associated herpesvirus- and Epstein-Barr virus-positive PEL cell line. Overall, our results demonstrate for the first time that brentuximab vedotin may serve as an effective therapy for PEL and provide strong preclinical indications for evaluation of brentuximab vedotin in clinical studies of PEL patients.

CYP3A-mediated drug-drug interaction potential and excretion of brentuximab vedotin, an antibody-drug conjugate, in patients with CD30-positive hematologic malignancies

Brentuximab vedotin is an antibody-drug conjugate (ADC) that selectively delivers monomethyl auristatin E (MMAE) into CD30-expressing cells. This study evaluated the CYP3A-mediated drug-drug interaction potential of brentuximab vedotin and the excretion of MMAE. Two 21-day cycles of brentuximab vedotin (1.2 or 1.8 mg/kg intravenously) were administered to 56 patients with CD30-positive hematologic malignancies. Each patient also received either a sensitive CYP3A substrate (midazolam), an effective inducer (rifampin), or a strong inhibitor (ketoconazole). Brentuximab vedotin did not affect midazolam exposures. ADC exposures were unaffected by concomitant rifampin or ketoconazole; however, MMAE exposures were lower with rifampin and higher with ketoconazole. The short-term safety profile of brentuximab vedotin in this study was generally consistent with historic clinical observations. The most common adverse events were nausea, fatigue, diarrhea, headache, pyrexia, and neutropenia. Over a 1-week period, ∼23.5% of intact MMAE was recovered after administration of brentuximab vedotin; all other species were below the limit of quantitation. The primary excretion route is via feces (median 72% of the recovered MMAE). These results suggest that brentuximab vedotin (1.8 mg/kg) and MMAE are neither inhibitors nor inducers of CYP3A; however, MMAE is a substrate of CYP3A.

Persistent CD30 expression by embryonal carcinoma in the treatment time course: prognostic significance of a worthwhile target for personalized treatment

PURPOSE

CD30 is expressed by untreated embryonal carcinoma, supporting the rationale for a targeted approach. However, the reported chemotherapy induced switching off of CD30 noted on immunohistochemistry may affect its therapeutic potential for disease relapse. We evaluated persistent CD30 expression and its prognostic meaning in cases of post-chemotherapy residual disease.

MATERIALS AND METHODS

Paraffin blocks of surgical samples that yielded nonteratomatous viable cells after 1 or more cisplatin based chemotherapy treatments were retrieved and reassessed by 2 pathologists blinded to the study purpose. Multivariable analysis was done for prespecified factors.

RESULTS

A total of 49 cases of pure embryonal carcinoma or mixed germ cell tumor from August 1991 to August 2012 had full clinical data and suitable tissue available for analysis. Of the 35 cases (71.4%, 95% CI 56.7-83.4) with preserved CD30 positivity 14 (40.0%) showed residual disease after a median of 1 regimen (IQR 1-2). Five-year overall survival in CD30 positive and negative cases was 37.0% (95% CI 22.1-61.8) and 50.1% (95% CI 27.9-90.0, p=0.078), while after first line treatment it was 23.2% (95% CI 8.6-62.5) and 47.6% (95% CI 18.8-100, p=0.025), respectively. On multivariable analysis CD30 positivity was a significant prognostic factor for progression-free survival (HR 2.32, 95% CI 1.04-5.19) and overall survival (HR 2.77, 95% CI 1.05-7.29).

CONCLUSIONS

CD30 was retained even after an intensive pretreatment load, confirming that it is a reliable treatment target. Its expression was associated with a significantly poorer prognosis in multiple relapse/chemoresistant cases and it was an independent prognostic factor for survival.

CD30 expression in high-risk acute myeloid leukemia and myelodysplastic syndromes

BACKGROUND

We assessed for CD30 expression in patients with acute myeloid leukemia (AML) or high-grade myelodysplastic syndrome (MDS) to examine the possibility that anti-CD30 could be targeted therapy in these patients.

METHODS

Multicolor flow cytometry immunophenotypic analysis was performed on bone marrow aspirates of 135 patients with AML or MDS and peripheral blood samples in a subset of 33 patients. Immunohistochemistry was performed on bone marrow aspirate clot specimens of 84 patients.

RESULTS

The median patient age was 63 years (range, 13-92 years); 102 (75%) patients had refractory or recurrent disease, and 68 (50%) had high-risk cytogenetics. Overall, the median percentage of blasts positive for CD30 was 14% (range, 0%-91%). By using an arbitrary 20% cutoff, 49 (36%) patients were considered to have CD30 expression. Monocytic cells, either mature or immature, were consistently negative for CD30. Therefore, CD30 expression was less in AML with monocytic differentiation (P = .006). The patients with persistent disease who had been actively treated had a higher level of CD30 expression than the patients who were untreated (P = .031). In paired samples, CD30 expression was consistently higher in bone marrow blasts than in peripheral blood blasts (P = .002). Immunohistochemistry demonstrated CD30 expression by myeloblasts in a subset of patients, but reactivity was generally weaker and focally compared.

CONCLUSIONS

CD30 is expressed by myeloblasts in a substantial subset of patients with AML or MDS. Because the study group was composed mostly of patients with high-risk AML or MDS in whom very few treatment options are available, these data raise the possibility that anti-CD30-targeted therapy could be a potential option for this patient group.

Risks and untoward toxicities of antibody-based immunoconjugates

Antibody-based immunoconjugates are specifically targeted monoclonal antibodies that deliver a cytotoxic payload to their target. The cytotoxic agents can be highly potent drugs, radionuclides or toxins. Such molecules, referred to as antibody-drug conjugates, radioimmunoconjugates and immunotoxins, respectively, represent a promising approach for enhancing the efficacy of unconjugated (naked) antibodies for improved therapeutic results. Though tremendous progress has been achieved over the last few decades, the safety of these molecules still remains a matter of concern and a careful design is required for achieving a relatively safe toxicity profile along with therapeutic effectiveness. This review focuses on the toxicities arising from the use of these potent agents.

Brentuximab vedotin

Brentuximab vedotin (SGN-35), an intravenously administered CD30-specific antibody-drug conjugate, has recently been approved by the U.S. Food and Drug Administration for two indications, including (i) patients with Hodgkin lymphoma relapsing after autologous stem-cell transplantation (ASCT), or after two multidrug regimens in patients with Hodgkin lymphoma who are not candidates for ASCT; and (ii) patients with systemic anaplastic large cell lymphoma (ALCL) who failed at least one prior multidrug chemotherapy regimen. Patients with Hodgkin lymphoma and ALCL treated with brentuximab vedotin showed markedly high response rates for a single agent, exceeding 70% and 80% for Hodgkin lymphoma and ALCL, respectively. The complete response rate was equally as impressive, at 34% and 57% for Hodgkin lymphoma and ALCL, respectively. Results like these and from many other upcoming clinical trials, in which brentuximab vedotin is being investigated in the frontline setting, promise to profoundly change how we manage the CD30-positive lymphoproliferative malignancies. The mechanism of action, preclinical antitumor activity, and clinical activity of brentuximab vedotin against Hodgkin lymphoma, ALCL, and other CD30-expressing lymphomas are reviewed.

Therapeutic antibodies against cancer

Antibody-based therapeutics against cancer are highly successful and currently enjoy unprecedented recognition of their potential; 13 monoclonal antibodies (mAbs) have been approved for clinical use in the European Union and in the United States. Bevacizumab, rituximab, and trastuzumab had sales in 2010 of more than $5 billion each. Hundreds of mAbs, including bispecific mAbs and multispecific fusion proteins, mAbs conjugated with small-molecule drugs, and mAbs with optimized pharmacokinetics, are in clinical trials. However, deeper understanding of mechanisms is needed to overcome major problems including resistance to therapy, access to targets, complexity of biological systems, and individual variations.

Histone acetylation and DNA demethylation of T cells result in an anaplastic large cell lymphoma-like phenotype

A characteristic feature of anaplastic large cell lymphoma is the significant repression of the T-cell expression program despite its T-cell origin. The reasons for this down-regulation of T-cell phenotype are still unknown. To elucidate whether epigenetic mechanisms are responsible for the loss of the T-cell phenotype, we treated anaplastic large cell lymphoma and T-cell lymphoma/leukemia cell lines (n=4, each) with epigenetic modifiers to evoke DNA demethylation and histone acetylation. Global gene expression data from treated and untreated cell lines were generated and selected, and differentially expressed genes were evaluated by real-time reverse transcriptase polymerase chain reaction and western blot analysis. Additionally, histone H3 lysine 27 trimethylation was analyzed by chromatin immunoprecipitation. Combined DNA demethylation and histone acetylation of anaplastic large cell lymphoma cells was not able to reconstitute their T-cell phenotype. Instead, the same treatment induced in T cells: (i) an up-regulation of anaplastic large cell lymphoma-characteristic genes (e.g. ID2, LGALS1, c-JUN), and (ii) an almost complete extinction of their T-cell phenotype including CD3, LCK and ZAP70. In addition, suppressive trimethylation of histone H3 lysine 27 of important T-cell transcription factor genes (GATA3, LEF1, TCF1) was present in anaplastic large cell lymphoma cells, which is in line with their absence in primary tumor specimens as demonstrated by immunohistochemistry. Our data suggest that epigenetically activated suppressors (e.g. ID2) contribute to the down-regulation of the T-cell expression program in anaplastic large cell lymphoma, which is maintained by trimethylation of histone H3 lysine 27.

Brentuximab Vedotin (SGN-35)

Brentuximab vedotin (SGN-35) is an antibody-drug conjugate (ADC) directed against the CD30 antigen expressed on Hodgkin lymphoma and anaplastic large cell lymphoma. SGN-35 consists of the cAC10 chimerized IgG1 monoclonal antibody SGN30, modified by the addition of a valine-citrulline dipeptide linker to permit attachment of the potent inhibitor of microtubule polymerization monomethylauristatin E (MMAE). In phase II trials, SGN-35 produced response rates of 75% in patients with Hodgkin lymphoma (n = 102) and 87% in patients with anaplastic large cell lymphoma (n = 30). Responses to SGN-35 might be related not only to the cytotoxic effect due to release of MMAE within the malignant cell but also to other effects. First, SGN-35 may signal malignant cells through CD30 ligation to deliver an apoptotic or proliferative response. The former would amplify the cytotoxicity of MMAE. A proliferative signal delivered in the context of MMAE intoxication could enhance cell death. Second, the efficacy of SGN-35, particularly in Hodgkin lymphoma, might be attributed to its effect on the tumor microenvironment. Diffusion of free MMAE from the targeted tumor cells could result in a bystander effect that kills the normal supporting cells in close proximity to the malignant cells. The elimination of T regulatory cells that inhibit cytotoxic effector cells and elimination of cells that provide growth factor support for Hodgkin/Reed-Sternberg cells could further enhance the cytotoxic activity of SGN-35. Here we review the biology of SGN-35 and the clinical effects of SGN-35 administration.

HIV-associated immune dysfunction and viral infection: role in the pathogenesis of AIDS-related lymphoma

HIV infection is associated with a much higher risk for the development of non-Hodgkin lymphoma (AIDS-NHL). The principal causes of lymphomagenesis in HIV-infected individuals are thought to be the loss of immune function seen in HIV infection, which results in the loss of immunoregulation of Epstein-Barr virus-infected B cells, as well as HIV infection-associated immune dysregulation, including chronic B-cell activation. In this review, we discuss recent reports that further support the importance of these factors, and we highlight emerging evidence of different mechanisms that potentially drive lymphomagenesis in HIV-infected individuals.

Brentuximab vedotin for the treatment of CD30+ lymphomas

Brentuximab vedotin is a novel antibody–drug conjugate consisting of the anti-CD30 antibody cAC10 chemically conjugated to monomethylauristatin E, a potent antimicrotubule agent. Preliminary response rates of 75% in relapsed/refractory Hodgkin’s lymphoma and 87% in relapsed/refractory systemic anaplastic large-cell lymphoma were recently reported in large Phase II trials. Brentuximab vedotin is well tolerated with manageable side effects including peripheral sensory neuropathy. This antibody–drug conjugate is currently under investigation in numerous clinical trials, including in combination with front-line chemotherapy for high-risk Hodgkin’s lymphoma and in a placebo-controlled, Phase III trial for patients with Hodgkin’s lymphoma at high risk for residual disease following autologous stem cell transplant. The impressive response rates and limited toxicity of brentuximab vedotin are very promising for relapsed/refractory patients with few treatment options. In addition, the possibilities for incorporation into front-line therapies for both Hodgkin’s lymphoma and systemic anaplastic large-cell lymphoma are intriguing.

Aberrant expression of CD30 in neoplastic mast cells in high-grade mastocytosis

Systemic mastocytosis either presents as aggressive neoplasm with short survival time or indolent systemic mastocytosis with normal life expectancy. In both instances, neoplastic mast cells usually harbor the D816V-mutated variant of KIT. Phenotypically, mast cells in systemic mastocytosis usually express CD25. However, no robust marker that discriminates between aggressive and indolent variants of systemic mastocytosis has been identified yet. We here report that CD30, also known as Ki-1 antigen, is expressed in neoplastic mast cells in a majority of patients with advanced systemic mastocytosis (11/13, 85%), whereas in most patients with indolent systemic mastocytosis (12/45, 27%; P<0.001), only a few if any mast cells stained positive for CD30. These results could be confirmed by TissueFAXS analysis in subsets of patients with indolent systemic mastocytosis (n=7) and advanced systemic mastocytosis (n=4; P=0.008). The mast cell leukemia cell line HMC-1, derived from a patient with aggressive systemic mastocytosis also expressed the CD30 protein. In addition, we were able to detect CD30 mRNA in HMC-1 cells as well as in bone marrow biopsy samples in patients with systemic mastocytosis. In contrast, CD30 transcripts could not be detected in bone marrow biopsies in cases of reactive mast cell hyperplasia and in various other myeloid neoplasms. In conclusion, CD30 is preferentially expressed in neoplastic mast cells in advanced mast cell neoplasms. Upregulated expression of CD30 in advanced systemic mastocytosis may thus be employed as a potential marker for grading systemic mastocytosis in hematopathology.

Aberrant expression of CD30 in aggressive systemic mastocytosis and mast cell leukemia: a differential diagnosis to consider in aggressive hematopoietic CD30-positive neoplasms

During the past two decades the immunophenotype of normal, reactive, and neoplastic mast cells (MCs) has been established. These studies have convincingly demonstrated that MCs form a separate lineage within the myeloid cell family. A most intriguing finding was that in contrast to normal MCs, neoplastic MCs in systemic mastocytosis (SM) aberrantly express several lymphoid marker antigens such as CD2 and CD25. This phenomenon has now been topped by the unexpected observation that neoplastic MCs in aggressive variants of SM and MC leukemia (leukemic variant of SM) aberrantly express CD30, whereas this antigen, Ki-1, is not detectable or is expressed only weakly in MCs in most patients with indolent SM. These observations may have implications for the evolution of SM as well as for diagnostic evaluation and grading in these patients. Moreover, these observations suggest that advanced SM has to be considered as a differential diagnosis of CD30-positive lymphoid neoplasms. Finally, CD30 may be considered as a potential target of antibody-based therapeutic intervention in advanced mast cell disorders.

Targeting CD30/CD30L in oncology and autoimmune and inflammatory diseases

The transmembrane receptor CD30 (TNFRSF8) and its ligand CD30L (CD153, TNFSF8) are members of the tumor necrosis factor (TNF) superfamily and display restricted expression in subpopulations of activated T-and B-cells in nonpathologic conditions. CD30 expression is upregulated in various hematological malignancies, including Reed-Sternberg cells in Hodgkin's disease (HD), anaplastic large cell lymphoma (ALCL) and subsets of Non-Hodgkin's lymphomas (NHLs). Increased CD30L expression was found on mast cells within HD tumors and preclinical and clinical studies with compounds targeting the CD30/ CD30L system in HD and ALCL demonstrated therapeutic benefit. Upregulation of CD30 and CD30L is also linked to leukocytes in patients with chronic inflammatory diseases, including lupus erythematosus, asthma, rheumatoid arthritis and atopic dermatitis (AD). Preclinical studies conducted with transgenic mice or biologic compounds suggested important regulatory functions of the CD30-CD30L system in various aspects of the immune system. Such key regulatory roles and their low expression in normal conditions combined with increased expression in malignant tissues provided a strong rationale to investigate CD30 and CD30L as therapeutic targets in hematologic malignancies, autoimmune and inflammatory diseases. In this report, we review the pharmacodynamic effects of specific therapeutic compounds targeting the CD30/CD30L system in preclinical- and clinical studies.

Using an RNA aptamer probe for flow cytometry detection of CD30-expressing lymphoma cells

Aptamers are small molecular ligands composed of short oligonucleotides that bind targets with high affinity. In contrast to antibodies, as synthetic oligonucleotides, aptamers have lower production costs and elicit no antigenic reactions. Therefore, aptamers are potential agents for disease diagnosis and treatment. In this study, we validate a fluorescently labeled RNA aptamer, which has been reported to bind specifically to mouse CD30 proteins in solution, for human CD30 protein recognition on intact cells. The aptamer probe was tested with cultured anaplastic large cell lymphoma and Hodgkin's lymphoma cells that express high levels of CD30. Flow cytometry and fluorescence microscopy showed specific and sensitive binding of the aptamer probe to CD30-expressing lymphoma cells at low concentrations (0.3 nM). Studies performed on multiple cell lines and nuclear cells from healthy donors confirmed that the CD30 aptamer and anti-CD30 antibody, the standard clinical probe, recognized the same set of cells. The potential application of multicolor flow cytometry analysis using the CD30 aptamer probe and antibodies was also shown. In conclusion, the developed CD30 aptamer probe could act as a replacement and/or a supplement for antibodies in the diagnosis of the CD30-expressing lymphomas.

Anaplastic large cell lymphoma with primary involvement of skeletal muscle: a rare case report and review of the literature

Primary skeletal muscle ALCL is very rare. Here the authors report a case of skeletal muscle ALCL that was proven pathologically. A 14-year-old boy presented with a persistent fever, chills, night sweats, headache, and significant weight loss. A CT scan of the abdomen showed a hazy mass about 3.2 x 1.2 cm in his left sacrospinalis. Ultrasonography revealed a low-echo and irregular mass in the left lumbar muscle measuring 8 x 1.4 x 3.6 cm in size and a similar mass 8 x 3.5 x 3.7 cm in size in the femoral muscle of the left thigh. MRI demonstrated an abnormal mass signal 4 x 3 x 9 cm in size infiltrating the left sacrospinalis muscle. The biopsy specimen was taken from the femoral muscle of the left thigh at surgery. Histopathological examination revealed a diffuse infiltration of large and atypical cells with pleomorphic nuclei and abundant cytoplasm. Immunohistological staining showed these atypical cells were positive for CD30 (Ki-l), anaplastic lymphoma kinase (ALK), epithelial membrane antigen (EMA), CD3, CD45RO, and CD68. The morphology and immunophenotype were consistent with CD30-positive, ALK-positive, and ALCL of T-cell lineage. The patient's condition was diagnosed as CD30-positive primary skeletal muscle ALCL.

The aryl hydrocarbon nuclear translocator alters CD30-mediated NF-kappaB-dependent transcription

Expression and signaling of CD30, a tumor necrosis factor receptor family member, is up-regulated in numerous lymphoid-derived neoplasias, most notably anaplastic large-cell lymphoma (ALCL) and Hodgkin's lymphoma. To gain insight into the mechanism of CD30 signaling, we used an affinity purification strategy that led to the identification of the aryl hydrocarbon receptor nuclear translocator (ARNT) as a CD30-interacting protein that modulated the activity of the RelB subunit of the transcription factor nuclear factor kappaB (NF-kappaB). ALCL cells that were deficient in ARNT exhibited defects in RelB recruitment to NF-kappaB-responsive promoters, whereas RelA recruitment to the same sites was potentiated, resulting in the augmented expression of these NF-kappaB-responsive genes. These findings indicate that ARNT functions in concert with RelB in a CD30-induced negative feedback mechanism.

Novel antibody approaches for T-cell lymphomas

T-cell lymphomas are biologically more aggressive--and less responsive than their B-cell counterparts--to conventional chemotherapy. The understanding of the normal physiology of T-cell signaling as well as the pathophysiology of T-cell neoplasia has advanced dramatically in the past decade. Thus, a number of novel cell surface therapeutic targets specific for T-cells have been identified and evaluated as potential monoclonal antibody (MoAb)-based therapeutic targets. Herein, we review a number of these cell surface targets and discuss the development and the clinical evaluation of MoAb therapies directed against these antigens.

Activated effector and memory T cells contribute to circulating sCD30: potential marker for islet allograft rejection

T-cell activation up-regulates CD30 resulting in an increase in serum soluble CD30 (sCD30). CD4+ T cells, a major source for sCD30, play a significant role in the pathogenesis of rejection. In this study, sCD30 was measured pre- and posttransplant in mouse islet allograft models and human islet allograft recipients. sCD30 was measured by ELISA in diabetic C57BL/6, CD4Knockout (KO) and CD8KO islet allograft recipients. sCD30 increased significantly prior to rejection (1.8 +/- 1 days) in 80% of allograft recipients. Sensitization with donor splenocytes, or a second graft, further increased sCD30 (282.5 +/- 53.5 for the rejecting first graft vs. 374.6 +/- 129 for the rejecting second graft) prior to rejection suggesting memory CD4+ T cells contribute to sCD30. CD4KO failed to reject islet allograft and did not demonstrate sCD30 increase. CD8KO showed elevated (227 +/- 107) sCD30 (1 day) prior to rejection. High pretransplant sCD30 (>20 U/ml) correlated with poor outcome in human islet allograft recipients. Further, increase in sCD30 posttransplant preceded (3-4 months) loss of islet function. We conclude that sCD30 is released from activated CD4 T cells prior to islet allograft rejection and monitoring sCD30 can be a valuable adjunct in the follow-up of islet transplant recipients.

Development of anaplastic lymphoma kinase (ALK) small-molecule inhibitors for cancer therapy

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase (RTK) involved in the genesis of several human cancers; indeed, ALK was initially identified in constitutively activated and oncogenic fusion forms--the most common being nucleophosmin (NPM)-ALK--in a non-Hodgkin's lymphoma (NHL) known as anaplastic large-cell lymphoma (ALCL) and subsequent studies identified ALK fusions in the human sarcomas called inflammatory myofibroblastic tumors (IMTs). In addition, two recent reports have suggested that the ALK fusion, TPM4-ALK, may be involved in the genesis of a subset of esophageal squamous cell carcinomas. While the cause-effect relationship between ALK fusions and malignancies such as ALCL and IMT is very well established, more circumstantial links implicate the involvement of the full-length, normal ALK receptor in the genesis of additional malignancies including glioblastoma, neuroblastoma, breast cancer, and others; in these instances, ALK is believed to foster tumorigenesis following activation by autocrine and/or paracrine growth loops involving the reported ALK ligands, pleiotrophin (PTN) and midkine (MK). There are no currently available ALK small-molecule inhibitors approved for clinical cancer therapy; however, recognition of the variety of malignancies in which ALK may play a causative role has recently begun to prompt developmental efforts in this area. This review provides a succinct summary of normal ALK biology, the confirmed and putative roles of ALK fusions and the full-length ALK receptor in the development of human cancers, and efforts to target ALK using small-molecule kinase inhibitors.

Clinical implication of natural killer cells and reproduction

The regulation of natural killer (NK) cells in the peripheral blood and endometrial layers has been associated with reproductive immunopathology such as recurrent spontaneous abortions (RSA), infertility of implantation failures, or pre-eclampsia. The placenta has a complex anatomical structure and different subsets of NK cells with various functional roles can directly interact with trophoblasts. NK cell subpopulations and their functions, putative roles of NK cells in peripheral blood and endometrium are reviewed in relation to RSA and infertility. An increase in NK cell numbers and /or activity in pre- or post-conceptional period in women with RSA or infertility with multiple implantation failures are a significant clinical concern. In addition, immuno-phenotypic characteristics of NK cells in these women support the changes for their increased activity status. Further studies are needed to explore underlying mechanism of NK cells in RSA, infertility, and other reproductive immunopathologies. Possible neurological and hormonal control of NK cells and NK cell interaction with various leukocyte populations need further investigation in women with reproductive failures.

A phase 1 multidose study of SGN-30 immunotherapy in patients with refractory or recurrent CD30+ hematologic malignancies

Phase 1 testing of SGN-30, a chimeric monoclonal antibody for the treatment of CD30+ malignancies, was conducted in a multicenter study. To explore the safety profile and establish the maximum tolerated dose (MTD), 24 patients with refractory or relapsed Hodgkin lymphoma or CD30+ non-Hodgkin lymphoma received 6 weekly doses of intravenous SGN-30 at 4 dose levels (2, 4, 8, or 12 mg/kg). Serum concentrations of SGN-30 rose rapidly and were dose dependent. Adverse events were mild, with nausea, fatigue, and fever attributed to study treatment. One episode of hypersensitivity rash was reported. The MTD was not reached. Serious adverse events included herpes zoster (n = 2), influenza, and pneumonia. One patient with cutaneous anaplastic large cell lymphoma (8 mg/kg) achieved a complete response. Six patients, of whom 4 had Hodgkin lymphoma, achieved stable disease with durations ranging from 6 to 16 months. The pharmacokinetic profile of SGN-30 showed a biphasic disposition, and estimated half-lives ranging between 1 to 3 weeks. The 6 weekly infusions of SGN-30 resulted in approximately 2- to 3-fold accumulation in serum exposures consistently across the dose range. These results demonstrate that weekly administration of SGN-30 is safe and has modest clinical activity in patients with CD30+ tumors. This trial is registered at http://www.ClinicalTrials.gov as no. NCT00051597.

CD30-induced signaling is absent in Hodgkin's cells but present in anaplastic large cell lymphoma cells

High CD30 expression in classical Hodgkin's lymphoma and anaplastic large cell lymphoma (ALCL) suggests an important pathogenic role of this cytokine receptor. To test this hypothesis, we investigated CD30 signaling in Hodgkin's and ALCL cell lines by different approaches: 1) CD30 stimulation, 2) CD30 down-regulation, and 3) a combination of both. The effects were determined at the RNA (microarray and real-time quantitative RT-PCR), protein (electrophoretic mobility shift analysis, immunoblot, and flow cytometry), and cellular/functional (proliferation and apoptosis) levels. We demonstrate that Hodgkin's cells are virtually CD30 unresponsive. Neither CD30 stimulation nor CD30 silencing of Hodgkin's cells had any significant effect. In contrast, CD30 stimulation of ALCL cells activated nuclear transcription factor-kappaB (NF-kappaB), induced major transcriptional changes, and decreased proliferation. These effects could be abrogated by down-regulation of CD30. Stimulation of CD30 in ALCL cells, stably transfected with a dominant-negative NF-kappaB inhibitor, induced pronounced caspase activation and massive apoptosis. Our data indicate that 1) CD30 signaling is not effective in Hodgkin's cell lines but is effective in ALCL cell lines, 2) CD30 is probably not significantly involved in the pathogenesis of classical Hodgkin's lymphoma, and 3) CD30 stimulation triggers two competing effects in ALCL cells, namely activation of caspases and NF-kappaB-mediated survival. These data suggest that CD30-targeted therapy in ALCL should be combined with NF-kappaB inhibitors to induce effective cell killing.

Macrophages contribute to the antitumor activity of the anti-CD30 antibody SGN-30

Increased expression of CD30 is associated with a variety of hematologic malignancies, including Hodgkin disease (HD) and anaplastic large cell lymphoma (ALCL). The anti-CD30 monoclonal antibody SGN-30 induces direct antitumor activity by promoting growth arrest and DNA fragmentation of CD30(+) tumor cells. In this study, we investigated the contributions of Fc-mediated effector cell functions to SGN-30 activity. We determined that antibody-dependent cellular phagocytosis, mediated by macrophages, to contribute significantly to antitumor activity in vitro. To delineate the identity of the host effector cells involved in mediating antitumor activity in vivo, we studied the effects of effector cell ablation in a disseminated model of HD (L540cy). Depletion of macrophages markedly reduced efficacy of SGN-30, demonstrating that macrophages contribute significantly to SGN-30 efficacy in this model. These findings may have implications for patient stratification or combination treatment strategies in clinical trials conducted with SGN-30 in HD and ALCL.

Characteristics of novel myeloid precursor cell line, PC-MDS, established from a bone marrow of the patient with therapy-related myelodysplastic syndrome

We report on characteristics of the first human cell line, PC-MDS, derived from a bone marrow of a patient with therapy-related myelodysplastic syndrome (t-MDS) who had no overt post-MDS leukemia. Classic cytology analyses, immunophenotyping, cytogenetic and molecular genetic procedures were used for characterization of the cell line. PC-MDS cells are positive for the expression of CD13, CD15, CD30, CD33, and CD45 antigen. Positive cytochemical staining and immunophenotype analyses indicated that PC-MDS cells have some characteristics of the early myeloid precursor cell. The karyotype analysis of PC-MDS cell line revealed various numerical and structural changes including those typically associated with t-MDS: del(5)(q13)[7], der(5)t(5;11)(p11;q11)[13], -7[6], del(7)(q31)[2], +20[3], -20[4]. Evaluation of methylation status in a promoter region of p15, p16 and MGMT genes showed biallelic hypermethylation pattern of 5' promoter region only in MGMT gene. PC-MDS is the first t-MDS derived cell line, and based on its immunological, cytogenetic and molecular characterization could be a new tool in evaluation of complex biology of MDS and a model for methylation studies.

CD30 Activates Both the Canonical and Alternative NF-κB Pathways in Anaplastic Large Cell Lymphoma Cells

CD30 is a member of the tumor necrosis factor receptor superfamily whose expression is up-regulated on anaplastic large cell lymphoma (ALCL) and Hodgkin lymphoma (HL) cells. Many different outcomes of CD30 stimulation have been reported, including cell cycle arrest, apoptosis, and activation of the prosurvival transcription factor, NF-kappaB, although this last activity is much less well defined in ALCL cells. In order to better understand the signaling properties of CD30 in cancer, we established a system for the stimulation of CD30 with its physiological ligand. Using this system, CD30 was stimulated on ALCL and HL cells, and the subsequent CD30 signaling properties were characterized. We show that a fraction of ALCL cells rapidly underwent apoptosis following CD30 stimulation, whereas HL cells were unaffected. The surviving ALCL cells exhibited robust activation of both the canonical and alternative NF-kappaB pathways as measured by nuclear translocation of RelA, p50, RelB, and p52, and this culminated in the transactivation of classical NF-kappaB-responsive genes. With prolonged CD30 stimulation, ALCL cells underwent cell cycle arrest that correlated with expression of the cell cycle inhibitor p21(waf1). Furthermore, p21(waf1) expression and cell cycle arrest were found to depend predominantly on the canonical NF-kappaB pathway, since it was reversed by RNA interference-mediated suppression of RelA. In contrast, suppression of the p100/p52 NF-kappaB subunit had little effect on p21(waf1). These data reveal that in ALCL cells, in contrast to other cell types, CD30 stimulation elicits p21(waf1)-mediated arrest through the canonical but not the alternative NF-kappaB pathway.

The expression of CD30 in anaplastic large cell lymphoma is regulated by nucleophosmin-anaplastic lymphoma kinase-mediated JunB level in a cell type-specific manner

Chromosomal translocation t(2;5) and the resulting fusion protein nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) are detected in 50% to 70% of anaplastic large cell lymphoma (ALCL), which is a T/null cell non-Hodgkin's lymphoma showing anaplastic morphology with cell surface expression of CD30. Because aberrant CD30 expression was also observed in the T-cell lymphoma derived from lineage-specific NPM-ALK transgenic mice, we tested the hypothesis that there might be a functional relationship between the two neoplastic-related proteins: NPM-ALK and CD30. In this study, we used the RNA interference method to modulate NPM-ALK protein expression in ALCL-derived, t(2;5)-positive Karpas 299 cells. We observed decreased CD30 expression when NPM-ALK was repressed. Further analysis suggested that JunB functioned as the mediator of NPM-ALK-derived CD30 transcriptional regulation. The NPM-ALK-repressed cells, which had low CD30 expression, were characterized with lower cell proliferation compared with cells in the control group, suggesting that altered CD30 expression may correlate to NPM-ALK-mediated tumor cell growth inhibition. Combination of NPM-ALK repression and CD30 ligand leads to significantly increased tumor cell growth inhibition compared with one method alone, suggesting its potential application for ALCL-specific cancer treatment.

Unexpected features of acute T lymphoblastic lymphomas in Notch1IC transgenic rats

Dysregulated Notch signaling accounts for the majority of acute T lymphoblastic leukemia/lymphoma (T-ALL) cases in humans. Here, we characterize lymphomas from Notch1IC transgenic rats, which develop T-ALL shortly after weaning, and show that they display a number of previously undocumented features. Starting from monoclonal thymic tumors, the CD4(+)CD8alphaalpha(+) lymphoma cells infiltrate the bone marrow and then spread to secondary lymphoid and non-lymphoid organs. However, major hallmarks of T-ALL cells in other murine models and human patients, such as constitutive NF-kappaB activity and increased levels of anti-apoptotic proteins, are remarkably absent in Notch1IC lymphomas. In contrast, CD30, a classic marker of Hodgkin lymphomas, is overexpressed in these tumors. Intriguingly, enforced Notch1 signaling up-regulates expression of Notch3, which has also been implicated in the pathogenesis of T-ALL. By blocking endogenous Notch signaling, we could demonstrate that Notch1IC is sufficient to induce sustained preTCR expression in transgenic thymocytes but not for their progression to the double-positive stage. This suggests that other Notch activities may also contribute to the phenotype of the transgenic rats. In summary, we anticipate this new animal model will help to further elucidate the role of Notch1 in the pathogenesis of T-ALL.