Search

The key role of RUNX3 in physiological T-cell differentiation has been extensively documented. However, information on its relevance for the development of human T-cell lymphomas or leukemias is scarce. Here, we show that alterations of RUNX3 by either heterozygous deletion or methylation of its distal promoter can be observed in the tumor cells of 15 of 21 (71%) patients suffering from Sézary syndrome, an aggressive variant of cutaneous T-cell lymphoma. As a consequence, mRNA levels of RUNX3/p46, the isoform controlled by the distal promoter, are significantly lower in Sézary syndrome tumor cells. Re-expression of RUNX3/p46 reduces cell viability and promotes apoptosis in a RUNX3/p46 low cell line of cutaneous T-cell lymphoma. Based on this, we present evidence that RUNX3 can act as a tumor suppressor in a human T-cell malignancy and suggest that this effect is predominantly mediated through transcripts from its distal promoter, in particular RUNX3/p46., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

Despite intensive efforts in recent years, a curative therapy for cutaneous T-cell lymphoma (CTCL) has not yet been developed. Therefore, the establishment of new therapeutic approaches with higher efficacy rates and milder side effects is strongly desired. A characteristic feature of the malignant T-cell population in CTCL is resistance toward cell death resulting from constitutive NF-κB activation. Therefore, NF-κB-dependent cell death resistance represents an interesting therapeutic target in CTCL because an NF-κB-directed therapy would leave bystander T cells widely unaffected. We investigated the effects of dimethyl fumarate (DMF) on CTCL cells in vitro and in vivo. DMF induced cell death in primary patient-derived CD4(+) cells and CTCL cell lines, but hardly in T cells from healthy donors. DMF-induced cell death was linked specifically to NF-κB inhibition. To study the impact of DMF in vivo, we developed 2 CTCL xenograft mouse models with different cutaneous localizations of the T-cell infiltrate. DMF treatment delayed the growth of CTCL tumors and prevented formation of distant metastases. In addition, DMF induced increased cell death in primary CTCL tumors and in liver metastases. In summary, DMF treatment represents a remarkable therapeutic option in CTCL because it restores CTCL apoptosis in vitro and in preclinical models in vivo and prevents spreading of the disease to distant sites. DMF treatment is of particular promise in CTCL because DMF is already in successful clinical use in the treatment of psoriasis and multiple sclerosis allowing fast translation into clinical studies in CTCL., (© 2016 by The American Society of Hematology.)

Cutaneous T-cell lymphomas (CTCL) are characterized by an infiltration of the skin with malignant T cells. Curative treatments for aggressive entities such as Sézary syndrome have not been identified yet. Arsenic trioxide (AsO3) is used for the treatment of acute promyelocytic leukemia in combination with retinoids. As the latter are established treatment options in CTCL, we sought to evaluate the efficacy of AsO3 for mono- and combination therapy in vitro. Analyses for apoptosis, cell cycle inhibition, cytotoxicity and cell viability were made after incubation of CTCL cells with AsO3 alone or in combination with the retinoids all-trans-retinoic acid or bexarotene. While AsO3 induced apoptosis, retinoids did not at the time point of analysis. However, retinoids strongly reduced cell viability. Due to the efficient apoptosis induction, AsO3 might be a potentially suitable agent for CTCL treatment, although this effect was not increased by retinoids., (© 2016 S. Karger AG, Basel.)

Cutaneous T-cell lymphomas (CTCLs) form a heterogeneous group of non-Hodgkin's lymphomas characterized by only poor prognosis in advanced stage. Despite significant progress made in the identification of novel genes and pathways involved in the pathogenesis of cutaneous lymphoma, the therapeutic value of these findings has still to be proven. Here, we demonstrate by gene expression arrays that Aurora kinase A is one of the highly overexpressed genes of the serine/threonine kinase in CTCL. The finding was confirmed by quantitative reverse transcriptase-PCR, western blotting, and immunohistochemistry in CTCL cell lines and primary patient samples. Moreover, treatment with a specific Aurora kinase A inhibitor blocks cell proliferation by inducing cell cycle arrest in G2 phase, as well as apoptosis in CTCL cell lines. These data provide a promising rationale for using Aurora kinase A inhibition as a therapeutic modality of CTCL.

Background and Objectives: Erythrodermic cutaneous T-cell lymphomas are aggressive diseases posing diagnostic and therapeutic challenges. Numerous indicators for confirming diagnosis and disease-monitoring have been proposed. CD26-negativity of peripheral CD4+ T-cells has been reported to have these properties. Our aim was to test, if the CD4(+) T-cell count, fraction of CD26- or CD7-negative CD4+ T-cells during the course of disease are valuable markers to predict therapeutic efficacy or disease progression in relation to changes in skin status., Patients and Methods: Retrospective cohort analysis of eleven patients treated at a tertiary referral centre. Statistics were done by linear regression analysis and logrank test., Results: Five patients displayed response to therapy in the skin, nine in the blood. Patients with cutaneous response showed a decrease of CD4+ T-cells, preceding the clinical response in most patients, whereas the percentage of CD26-negative T-cells changed first during clinical improvement. The calculated positive predictive values for response or progression were low for both CD4-count and CD26-expression., Conclusions: CD26 is not a reliable marker of either response or progression. As cutaneous response was always associated with a response in blood and not vice versa, we conclude, that the clinical status represents the most important parameter for guiding therapeutic decisions., (© 2014 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.)

Detection of a dominant T-cell clone by T-cell receptor (TCR) gene rearrangement analysis is often essential for the diagnosis of cutaneous T-cell lymphomas (CTCL). The occurrence of T-cell clones in addition to the diagnostic T-cell clone during the course of CTCL has been reported, but the data of these studies have been contradictory. We retrospectively evaluated the data of 114 lesional skin biopsies from 26 patients with Mycosis fungoides and two patients with primary cutaneous anaplastic large cell lymphoma, which were analysed with the standardized Biomed-2 PCR for the TCRγ and TCRβ locus. A dominant T-cell clone was repetitively detected in 93% (26/28) of patients. Additional T-cell clones appeared temporarily in 39% (11/28) of patients. Correlation with the clinical data did not show an association of the presence of additional T-cell clones with age, number of treatments, progression of disease or survival. Our findings demonstrate that a persistent T-cell clone, most likely the disease causing tumor clone, is detectable in almost all CTCL patients. In addition, transiently appearing T-cell clones frequently occur during the course of disease. The biological relevance of these additional clones has still to be determined. However, it is important to take the possibility of additional T-cell clones into account for diagnostic analyses., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Suberoylanilide hydroxamic acid (SAHA) has been approved for the treatment of cutaneous T-cell lymphoma (CTCL), but its mode of action remained largely elusive. As shown here in four CTCL cell lines, loss of cell viability correlated with significant time- and dose-dependent induction of apoptosis, whereas cytotoxicity was less pronounced. Both extrinsic and intrinsic apoptosis pathways were activated, as seen by processing of initiator caspases 8 and 9, loss of mitochondrial membrane potential, and cytochrome c release. Characteristically, antiapoptotic mediators such as Mcl-1, XIAP, survivin, and c-FLIP were downregulated. Consistent with its critical function, c-FLIP overexpression resulted in a significant decrease of SAHA-mediated apoptosis. Enhanced sensitivity to TRAIL (TNF-related apoptosis-inducing ligand) and enhanced TRAIL signaling was seen in CTCL cell lines with high sensitivity, whereas cell lines with moderate response were characterized by downregulation of TRAIL-R2 and weaker TRAIL expression. Comparable proapoptotic responses to SAHA and to the combination with TRAIL were seen in ex vivo tumor T cells of CTCL patients. Thus, activation of extrinsic apoptosis pathways, related to c-FLIP downregulation and enhanced TRAIL signaling, appeared as characteristic for CTCL cell responsiveness to SAHA. An improved understanding of the pathways may facilitate its targeted use and the selection of suitable combinations.

Cutaneous T-cell lymphomas (CTCL) form a heterogeneous group of non-Hodgkin's lymphomas of the skin. In previous studies, we had characterized CTCL cells as resistant to the death ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), which correlated to pronounced expression of the caspase-8/-10 inhibitor c-FLIP. For identification of proapoptotic strategies in CTCL cells and for overcoming their death ligand resistance, we investigated the effects of nonsteroidal anti-inflammatory drugs (NSAIDs) such as acetylsalicylic acid, sodium salicylate, and diclofenac (DF). These drugs strongly enhanced apoptosis, as well as decreased CTCL cell proliferation and vitality, and DF furthermore sensitized for TRAIL-induced apoptosis. Full activation of the caspase cascade (caspase-3, -8, -9) and decreased mitochondrial membrane potential were characteristic for NSAID treatment, whereas cytochrome c release was seen only for DF. Downregulation of Mcl-1 and enhanced surface expression of TRAIL were seen in response to NSAIDs. Most characteristic for apoptosis induction was the downregulation of c-FLIP. In agreement with the critical role of c-FLIP for apoptosis deficiency of CTCL cells, its overexpression decreased NSAID-mediated apoptosis and its downregulation by small hairpin RNA-enhanced apoptosis. The study provides a rationale for the use of NSAIDs as a new therapeutic option for CTCL patients. Supporting this concept, ex vivo lymphoma cells of CTCL patients also revealed significant sensitivity for NSAID treatment.

Recently, several European centers of lymphoma diagnosis and research developed various polymerase chain reaction (PCR) methods for clonality analysis in suspect T-cell and B-cell proliferations (Biomed-2 Concerted Action). They have mainly been applied to frozen material of systemic B-cell and T-cell malignancies. Thus far, only limited data exist with regard to cutaneous T-cell lymphoma (CTCL) and paraffin-embedded material. Thus, we applied the Biomed-2 T-cell receptor (TCR) gamma and TCRbeta PCR as well as an in-house TCRgamma PCR to a collection of 107 archival skin samples (84 CTCL, 3 systemic TCL and 20 controls). As a result, the Biomed-2 TCRgamma PCR revealed 81% clonality, the in-house TCRgamma method revealed 86% clonality, and the Biomed-2 TCRbeta revealed 78% clonality in CTCL samples generating at least the 300 bp fragment in the Biomed-2 control PCR. We found clonal TCRbeta rearrangements in 5 of 17 CTCL samples that were polyclonal in the Biomed-2 TCRgamma PCR. By combining all Biomed-2 assays, one or more clonal rearrangements were detected in 87% of CTCL and in all 3 systemic TCLs. By combining all TCR PCR assays applied here, clonality was shown in 90% of the CTCL cases. In conclusion, we showed that the Biomed-2 TCR PCR worked well with DNA from paraffin-embedded tissue, revealing a high-clonality detection rate in CTCL, and thus should be highly recommended for routine molecular analysis. In addition, the performance of our in-house TCRgamma assay verifies our previously published findings on clonally expanded T-cells in CTCL.