Cutaneous T-Cell Lymphoma: A Paradigm for Biological Therapies

Spatially Resolved Single-Cell Transcriptome Analysis of Mycosis Fungoides Reveals Distinct Biomarkers GNLY and FYB1 Compared With Psoriasis and Chronic Spongiotic Dermatitis

Early mycosis fungoides (MF) and inflammatory dermatoses including psoriasis and chronic spongiotic dermatitis are often difficult to differentiate. We explored diagnostic markers differentiating MF from psoriasis and chronic spongiotic dermatitis via spatially resolved single-cell transcriptome analysis. Single-cell transcriptomics of intraepidermal T cells of MF patches, psoriasis, and chronic spongiotic dermatitis were analyzed using CosMx spatial molecular imager utilizing surface markers, including CD3 and CD4. An immunohistochemical study with potential markers was performed to verify clinical utility. Compared with psoriasis and chronic spongiotic dermatitis, 41 upregulated differentially expressed genes (DEGs) in MF were associated with the T-cell receptor (TCR) signaling pathway and apoptosis regulation. Protein-protein interaction network analysis of these DEGs revealed a main cluster associated with TCR signaling. Pathway enrichment analysis showed that apoptosis, Th17 cell differentiation, and TCR signaling pathways were enriched in MF. GNLY and FYB1, DEGs with the highest fold-change values, were selected as potential diagnostic biomarkers for MF. For immunohistochemistry, biopsy specimens from 150 patients diagnosed with patch MF with CD4+ immunophenotype (n = 56), psoriasis (n = 48), and chronic eczema (n = 46) were included. The sensitivity and specificity of granulysin (GNLY) for distinguishing MF and psoriasis/chronic spongiotic dermatitis were 67.9% and 93.6%, respectively. For FYN-binding protein 1 (FYB1), those values were 73.2% and 69.2%, respectively. The area under the receiver operating characteristic curve values of GNLY and FYB1 were 0.86 and 0.79, respectively. In conclusion, granulysin and FYB1 can be promising diagnostic biomarkers for differentiating early-stage MF from psoriasis and chronic spongiotic dermatitis.

mAb14, a Monoclonal Antibody against Cell Surface PCNA: A Potential Tool for Sezary Syndrome Diagnosis and Targeted Immunotherapy

Mycosis fungoides (MF) and Sézary syndrome (SS) are the most common types of primary cutaneous T-cell lymphoma (CTCL). Proliferating cell nuclear antigen (PCNA) is expressed on the cell surface of cancer cells (csPCNA), but not on normal cells. It functions as an immune checkpoint ligand by interacting with natural killer (NK) cells through the NK inhibitory receptor NKp44, leading to the inhibition of NK cytotoxicity. A monoclonal antibody (mAb14) was established to detect csPCNA on cancer cells and block their interaction with NKp44. In this study, three CTCL cell lines and peripheral blood mononuclear cells (PBMCs) from patients with SS and healthy donors were analyzed for csPCNA using mAb14, compared to monoclonal antibody PC10, against nuclear PCNA (nPCNA). The following assays were used: immunostaining, imaging flow cytometry, flow cytometry, cell sorting, cell cycle analysis, ELISA, and the NK-cell cytotoxic assay. mAb14 successfully detected PCNA on the membrane and in the cytoplasm of viable CTCL cell lines associated with the G2/M phase. In the Sézary PBMCs, csPCNA was expressed on lymphoma cells that had an atypical morphology and not on normal cells. Furthermore, it was not expressed on PBMCs from healthy donors. In the co-culture of peripheral blood NK (pNK) cells with CTCL lines, mAb14 increased the secretion of IFN-γ, indicating the reactivation of pNK activity. However, mAb14 did not enhance the cytotoxic activity of pNK cells against CTCL cell lines. The unique expression of csPCNA detected by mAb14 suggests that csPCNA and mAb14 may serve as a potential biomarker and tool, respectively, for detecting malignant cells in SS and possibly other CTCL variants.

Cell signaling in cutaneous T-cell lymphoma microenvironment: promising targets for molecular-specific treatment

Cutaneous T-cell lymphomas (CTCL) result from the infiltration and proliferation of a population of T cells in the skin, inducing changes in the activity of both T cells and surrounding skin cells. In the CTCL microenvironment, cell interactions mediated by cell signaling pathways are altered. Defining changes in cell signaling enables to understand T-cell deregulations in the CTCL microenvironment and thus the progression of the disease. Moreover, characterizing signaling networks activated in CTCL stages can lead to consider new molecular biomarkers and therapeutic targets. Focusing on mycosis fungoides (MF), the most frequent variant of CTCL, and Sézary syndrome (SS), its leukemic variant, this review highlights recent molecular and genetic findings revealing modifications of key signaling pathways involved in (1) cell proliferation, cell growth, and cell survival such as MAP kinases and PI3K/Akt; (2) immune responses derived from TCR, TLR, JAK/STAT, and NF-kB; and (3) changes in tissue conditions such as extracellular matrix remodeling, hypoxia, and angiogenesis. Alterations in these signaling networks promote malignant T-cell proliferation and survival, T-cell migration, inflammation, and suppression of immune regulation of malignant T cells, making a skin microenvironment that allows disease progression. Targeting key proteins of these signaling pathways, using molecules already available and used in research, in clinical trials, and with other disease indications, can open the way to different therapeutic options in CTCL treatment.

New Therapies and Immunological Findings in Cutaneous T-Cell Lymphoma

Primary cutaneous lymphomas comprise a group of lymphatic malignancies that occur primarily in the skin. They represent the second most common form of extranodal non-Hodgkin’s lymphoma and are characterized by heterogeneous clinical, histological, immunological, and molecular features. The most common type is mycosis fungoides and its leukemic variant, Sézary syndrome. Both diseases are considered T-helper cell type 2 (Th2) diseases. Not only the tumor cells but also the tumor microenvironment can promote Th2 differentiation, which is beneficial for the tumor cells because a Th1 environment enhances antitumor immune responses. This Th2-dominant milieu also underlies the infectious susceptibility of the patients. Many components, such as tumor-associated macrophages, cancer-associated fibroblasts, and dendritic cells, as well as humoral factors, such as chemokines and cytokines, establish the tumor microenvironment and can modify tumor cell migration and proliferation. Multiagent chemotherapy often induces immunosuppression, resulting in an increased risk of serious infection and poor tolerance. Therefore, overtreatment should be avoided for these types of lymphomas. Interferons have been shown to increase the time to next treatment to a greater degree than has chemotherapy. The pathogenesis and prognosis of cutaneous T-cell lymphoma (CTCL) differ markedly among the subtypes. In some aggressive subtypes of CTCLs, such as primary cutaneous gamma/delta T-cell lymphoma and primary cutaneous CD8⁺ aggressive epidermotropic cytotoxic T-cell lymphoma, hematopoietic stem cell transplantation should be considered, whereas overtreatment should be avoided with other, favorable subtypes. Therefore, a solid understanding of the pathogenesis and immunological background of cutaneous lymphoma is required to better treat patients who are inflicted with this disease. This review summarizes the current knowledge in the field to attempt to achieve this objective.

Targeting Thioredoxin-1 by dimethyl fumarate induces ripoptosome-mediated cell death

Constitutively active NFκB promotes survival of many cancers, especially T-cell lymphomas and leukemias by upregulating antiapoptotic proteins such as inhibitors of apoptosis (IAPs) and FLICE-like inhibitory proteins (cFLIPs). IAPs and cFLIPs negatively regulate the ripoptosome, which mediates cell death in an apoptotic or necroptotic manner. Here, we demonstrate for the first time, that DMF antagonizes NFκB by suppressing Thioredoxin-1 (Trx1), a major regulator of NFκB transcriptional activity. DMF-mediated inhibition of NFκB causes ripoptosome formation via downregulation of IAPs and cFLIPs. In addition, DMF promotes mitochondrial Smac release and subsequent degradation of IAPs, further enhancing cell death in tumor cells displaying constitutive NFκB activity. Significantly, CTCL patients treated with DMF display substantial ripoptosome formation and caspase-3 cleavage in T-cells. DMF induces cell death predominantly in malignant or activated T-cells. Further, we show that malignant T-cells can die by both apoptosis and necroptosis, in contrast to resting T-cells, which are restricted to apoptosis upon DMF administration. In summary, our data provide new mechanistic insight in the regulation of cell death by targeting NFκB via Trx1 in cancer. Thus, interference with Trx1 activity is a novel approach for treatment of NFκB-dependent tumors.

Efficacy and safety of denileukin diftitox retreatment in patients with relapsed cutaneous T-cell lymphoma

This open-label phase III trial, a companion to an earlier placebo-controlled trial, evaluated safety and efficacy of denileukin diftitox (DD) in patients with cutaneous T-cell lymphoma (CTCL) who relapsed after responding to DD primary treatment in the earlier trial. Twenty relapsed patients (stages IA-III) received DD 18 μg/kg/day intravenously on days 1-5 of a 21-day cycle, for ≤ 8 cycles. Efficacy was assessed monthly during the first year then every 3 months. The overall response rate was 40%, mostly partial responses. Nine patients (all baseline stages ≤ IIA) experienced progression. Intent-to-treat median progression-free survival was 205 days, and median duration of response was 274 days. The most common adverse events were nausea, upper respiratory tract infections, fatigue and rigors. Three patients withdrew because of toxicity. This study showed that DD may provide clinically meaningful benefit in patients with CTCL who relapsed after initial response to DD.

Cyclosporine, prednisone, and high-dose immunoglobulin treatment of angioimmunoblastic T-cell lymphoma refractory to prior CHOP or CHOP-like regimen

Angioimmunoblastic T-cell lymphoma (AITL) is a rare, distinct subtype of peripheral T-cell lymphoma, possessing an aggressive course and poor prognosis with no standard therapy. Twelve patients who have failed at least two initial CHOP or CHOP-like regimens were enrolled in this study and treated with individualized cyclosporine (CsA), prednisone (PDN), and monthly, high-dose intravenous immunoglobulin (HDIVIG). The dose of CsA was adjusted individually based on the blood trough concentration of CsA and renal function. All patients were examined for response, toxicity and survival. The most significant toxicities (≥ grade 2) were infection (16.7%), renal insufficiency (8.3%), hypertension (8.3%), diabetes (8.3%) and insomnia (16.7%). Discontinuation of treatment occurred in one patient (8.3%) due to grade 3 renal toxicity and subsequent grade 4 pulmonary infection. Treatment-related death was not observed. The overall response rate was 75.0% (complete response, 33.3%; partial response, 41.7%). With a median follow-up of 25.5 months, the median duration of response was 20 months (range, 12 to 49 months) and the median progression-free survival (PFS) was 25.5 months (range, 10 to 56 months). The 2-year PFS rate was 81.5%. Our findings indicate the combination of CsA, PDN and HDIVIG is an effective salvage regimen for refractory or relapsed AITL with predictable and manageable toxicity.

Immunomodulatory therapy of cutaneous T-cell lymphoma: a multimodality approach in advanced disease

Dialogues in Dermatology, a monthly audio program from the American Academy of Dermatology, contains discussions between dermatologists on timely topics. Commentaries from Dialogues Editor-in-Chief Jacqueline M. Junkins-Hopkins, MD, are provided after each discussion as a topic summary and are provided here as a special service to readers of the Journal of the American Academy of Dermatology.

[Subcutaneous panniculitis-like T-cell lymphoma]

Subcutaneous panniculitis-like T-cell lymphoma is extremely rare and has recently been recognized as a clinicopathological entity. Young female, 17 years old, has complained of subcutaneous nodules and plaques in the limbs and abdomen for three years, accompanied of mild weight loss without other constitutional symptoms. Nodal, visceral and bone marrow involvement was absent, and subcutaneous CD3/CD8 atypical lymphocyte infiltration was observed in the skin sample. Chemotherapy interrupted the onset of new lesions and led to remission in the 8-month follow-up. Immunophenotypic and molecular aspects were relevant to the diagnosis and as prognosis makers.

An uncommon skin condition illustrates the need for caution when prescribing for friends

PURPOSE

A dual-focused case study written to discuss the legal and medical hazards of informally writing prescriptions for friends or family members and to provide knowledge of early-stage mycosis fungoides (MF), its course, and treatment.

DATA SOURCES

A review of the prescribing practices of clinicians, the cognitive processes needed in diagnosis and treatment, the current ethical guidelines, and a review of MF, its course, and treatments.

CONCLUSIONS

Treating acquaintances and family informally places clinicians at risk for liability and patients at risk for inaccurate diagnosis and treatment. This case illustrates the potential hazard of casually treating a friend for what looks like a benign condition. Resembling atopic dermatitis in its early stages, MF is the most common of a rare group of skin lymphomas. Early diagnosis and treatment are crucial for a better prognosis. Had this clinician complied with the request of her friend, his diagnosis would have been missed and timely treatment delayed.

IMPLICATIONS FOR PRACTICE

No matter what the prior relationship may have been, once a clinician treats a patient, a legally binding relationship begins, requiring the due standard of care. Nurse practitioners (NPs) need to be aware of the potential for error when treating acquaintances. Available NP standards of practice and ethical guidelines should address informal treatment situations.

Haematopoietic stem cell transplantation for patients with primary cutaneous T-cell lymphoma

There is no standard of care for patients with advanced forms of mycosis fungoides, Sézary syndrome and other less common subtypes of primary cutaneous T-cell lymphoma. Expected median survival for such patients with conventional therapy is only 1-4 years. As a result of such dismal prognosis, alternative strategies based on autologous and allogeneic transplantation have been explored, and a relatively small number of case reports and small series communicated to date have provided evidence for the potential role of haematopoietic transplantation in these patients. High-dose radio-chemotherapy and autologous rescue has been shown to induce complete responses in the majority of patients. Disappointingly though, these responses were very short-lived in nearly all cases. On the contrary, the use of allogeneic transplantation has provided solid evidence for an allogeneic GVL effect in these malignancies. In fact, more than two-thirds of the allogeneic transplant recipients reported in the literature experienced long-term durable remissions of more than 3 years, which would appear superior to the expected median survival for such patients. This review summarizes the experience published to date in this setting and highlights main areas that would merit further investigation.

Vorinostat: a new oral histone deacetylase inhibitor approved for cutaneous T-cell lymphoma

Epigenetic regulation of gene transcription by small-molecule inhibitors of histone deacetylases (HDACs) is a novel cancer therapy. Vorinostat (suberoylanilide hydroxamic acid) is the first FDA-approved HDAC inhibitor for the treatment of cutaneous manifestations of cutaneous T-cell lymphoma (CTCL). Vorinostat was active against solid tumors and hematologic malignancies as intravenous and oral preparations in Phase I development. In two Phase II trials, vorinostat 400 mg/day was safe and effective with an overall response rate of 24-30% in refractory advanced patients with CTCL including large cell transformation and Sézary syndrome. The common side effects of vorinostat, which are similar in all studies, include gastrointestinal symptoms, fatigue and thrombocytopenia and the most common serious event was thrombosis.

Interferon-? is effective for CD4+, CCR4? mycosis fungoides

Mycosis fungoides (MF), a cutaneous T-cell lymphoma, is usually characterized by cell features of T-helper-2 (Th2) lymphocytes. MF has recently been reported to show increased CCR4 expression, a chemokine receptor specifically expressed in Th2. Previously, we have reported the effectiveness of interferon-gamma (IFN-gamma) for the treatment of CCR4(+) MF. In this report, we describe two cases of CD4(+), CCR4(-) MF successfully treated with IFN-alpha, but not IFN-gamma. Although MF usually displays a Th2 profile, the tumor cells in our two cases did not express CCR4. Our cases suggest the effectiveness of IFN-alpha, but not IFN-gamma, for CCR4- MF.

Mycosis fungoides und chronisch lymphatische B-Zell-Leukämie

The simultaneous appearance of mycosis fungoides (MF) and B-cell chronic lymphocytic leukemia (B-CLL) in the same patient is extremely rare. Only seven cases have been described in literature. A 72-year-old patient was diagnosed with coincident MF, stage Ib, and B-CLL, Binet stage A. Hypotheses on simultaneous occurrence of B- and T-cell malignancies as well as a new therapeutic option are discussed.

Macromolecular immunosuppressants

Recombinant immunosuppressants have come of age and represent a significant class of quite diverse drugs. They target extracellular molecules, and either label or inhibit them. Those targets are soluble factors or membrane proteins almost all of which are components of a very complex molecular network of communication and amplification. Notably, many recombinant immunosuppressants have been developed in a rather short period of time. This is due to the fact that developing the actual drug is left to nature, so to speak; either it is a human protein as is the case for Anakinra or it is an antibody or antibody derivative "developed" by the immune system of mice or rats following exposure to the antigen. The challenge for developing recombinant immunosuppressants is to identify relevant targets. It is no longer very difficult to generate proteins to targets, once those are identified. The clinical use of recombinant immunosuppressants has yet to show which targets are truly relevant and which drugs prove effective.

Histone deacetylase inhibitors induce the degradation of the t(8;21) fusion oncoprotein

The t(8;21) chromosomal translocation that generates the fusion oncoprotein RUNX1-ETO predominates in leukemia patients of the French-American-British (FAB) class M2 subtype. The oncoprotein has the capacity to promote expansion of hematopoietic stem/progenitor cells and induces leukemia in association with other genetic alterations. Here, we show that RUNX1-ETO undergoes degradation in response to treatment with histone deacetylase inhibitors, one of which, depsipeptide (DEP), is currently undergoing phase II clinical testing in a variety of malignancies. These compounds induce turnover of RUNX1-ETO without affecting the stability of RUNX1-ETO partner proteins. In addition, RUNX1-ETO physically interacts with heat shock protein 90 (HSP90). DEP treatment interrupts the association of RUNX1-ETO with HSP90 and induces proteasomal degradation of RUNX1-ETO. DEP and the HSP90 antagonist 17-allylamino-geldanamycin (17-AAG) both triggered RUNX1-ETO degradation, but without any additive or cooperative effects. These findings may stimulate the development of more rational and effective approaches for treating t(8;21) patients using histone deacetylase inhibitors or HSP90 inhibitors.

Lymphocyte activation antigen CD70 expressed by renal cell carcinoma is a potential therapeutic target for anti-CD70 antibody-drug conjugates

Metastatic renal cell carcinoma (RCC) is an aggressive disease refractory to most existing therapeutic modalities. Identifying new markers for disease progression and drug targets for RCC will benefit this unmet medical need. We report a subset of clear cell and papillary cell RCC aberrantly expressing the lymphocyte activation marker CD70, a member of the tumor necrosis factor superfamily. Importantly, CD70 expression was found to be maintained at the metastatic sites of RCC. Anti-CD70 antibody-drug conjugates (ADC) consisting of auristatin phenylalanine phenylenediamine (AFP) or monomethyl auristatin phenylalanine (MMAF), two novel derivatives of the anti-tubulin agent auristatin, mediated potent antigen-dependent cytotoxicity in CD70-expressing RCC cells. Cytotoxic activity of these anti-CD70 ADCs was associated with their internalization and subcellular trafficking through the endosomal-lysosomal pathway, disruption of cellular microtubule network, and G2-M phase cell cycle arrest. The efficiency of drug delivery using anti-CD70 as vehicle was illustrated by the much enhanced cytotoxicity of antibody-conjugated MMAF compared with free MMAF. Hence, ADCs targeted to CD70 can selectively recognize RCC, internalize, and reach the appropriate subcellular compartment(s) for drug release and tumor cell killing. In vitro cytotoxicity of these ADCs was confirmed in xenograft models using RCC cell lines. Our findings provide evidence that CD70 is an attractive target for antibody-based therapeutics against metastatic RCC and suggest that anti-CD70 ADCs can provide a new treatment approach for advanced RCC patients who currently have no chemotherapeutic options.

Progress in drug development of immunostimulatory CpG oligodeoxynucleotide ligands for TLR9

Oligodeoxynucleotides (ODNs) with unmethylated deoxycytosine-deoxyguanosine (CpG) motifs are recognised by Toll-like receptor (TLR)9 expressed in specialised cell subsets of the human immune system, B cells and plasmacytoid dendritic cells. TLR9-mediated stimulation of the immune system leads to a plethora of directed effects linking innate to adaptive immune responses. This allows the use of TLR9 agonists as highly effective targeted immunomodulatory drugs with broad potential applications as vaccine adjuvants, stand-alone therapy or in combination with other therapies in cancer, infectious diseases or asthma and allergy. TLR9 agonists represent a new class of small (8-30 bases long), easily synthesised, non-antisense ODN pharmaceuticals.

Denileukin diftitox: a concise clinical review

Denileukin diftitox (DAB389IL-2; Ontak) is a novel recombinant fusion protein approved by the US Food and Drug Administration for the treatment of relapsed or refractory cutaneous T-cell lymphoma. It consists of fragments of diphtheria toxin linked to human interleukin-2 and works by targeting the high-affinity interleukin-2 receptor expressed on malignant cells. This article will review the clinical trials leading to the approval of denileukin diftitox for cutaneous T-cell lymphoma, and discuss the potential future role of this novel drug in patients with both malignant and nonmalignant diseases, including non-Hodgkin's lymphoma, chronic lymphocytic leukemia, solid tumors, psoriasis and graft-versus-host disease.

Signal transducer and activator of transcription (STAT) signalling and T-cell lymphomas

Interaction of cytokines with their cognate receptors leads to the activation of latent transcription factors - the signal transducers and activators of transcription (STAT) proteins - whose biological activities ultimately regulate many critical aspects of cell growth, survival and differentiation. Dysregulation of the JAK-STAT pathway is frequently observed in many primary human tumours, reflecting the importance of this pathway in the maintenance of cellular integrity. Here we review the current progress in STAT structure and function, and the contribution of STAT signalling to the pathogenesis of T-cell lymphomas.