Sézary Syndrome: Clinical and Biological Aspects

Development of Bexarotene Analogs for Treating Cutaneous T-Cell Lymphomas

Bexarotene, a drug approved for treatment of cutaneous T-cell lymphoma (CTCL), is classified as a rexinoid by its ability to act as a retinoid X receptor (RXR) agonist with high specificity. Rexinoids are capable of inducing RXR homodimerization leading to the induction of apoptosis and inhibition of proliferation in human cancers. Numerous studies have shown that bexarotene is effective in reducing viability and proliferation in CTCL cell lines. However, many treated patients present with cutaneous toxicity, hypothyroidism, and hyperlipidemia due to crossover activity with retinoic acid receptor (RAR), thyroid hormone receptor (TR), and liver X receptor (LXR) signaling, respectively. In this study, 10 novel analogs and three standard compounds were evaluated side-by-side with bexarotene for their ability to drive RXR homodimerization and subsequent binding to the RXR response element (RXRE). In addition, these analogs were assessed for proliferation inhibition of CTCL cells, cytotoxicity, and mutagenicity. Furthermore, the most effective analogs were analyzed via qPCR to determine efficacy in modulating expression of two critical tumor suppressor genes, ATF3 and EGR3. Our results suggest that these new compounds may possess similar or enhanced therapeutic potential since they display enhanced RXR activation with equivalent or greater reduction in CTCL cell proliferation, as well as the ability to induce ATF3 and EGR3. This work broadens our understanding of RXR-ligand relationships and permits development of possibly more efficacious pharmaceutical drugs. Modifications of RXR agonists can yield agents with enhanced biological selectivity and potency when compared to the parent compound, potentially leading to improved patient outcomes.

The Role of Tumor Microenvironment in the Pathogenesis of Sézary Syndrome

Sézary syndrome is an aggressive leukemic variant of cutaneous T-cell lymphomas, characterized by erythroderma, lymphadenopathy, and peripheral blood involvement by CD4+ malignant T-cells. The pathogenesis of Sézary syndrome is not fully understood. However, the course of the disease is strongly influenced by the tumor microenvironment, which is altered by a combination of cytokines, chemokines, and growth factors. The crosstalk between malignant and reactive cells affects the immunologic response against tumor cells causing immune dysregulation. This review focuses on the interaction of malignant Sézary cells and the tumor microenvironment.

[Minimal change nephropathy and IgA deposits associated with a Sezary syndrome]

INTRODUCTION

The Sézary syndrome (SS) is an aggressive form of cutaneous T-cell lymphoma (CTCL) requiring a rapid diagnosis due to its poor prognosis.

CASE REPORT

We report the first case of an eighty-nine-year-old woman who presented with concomitant Sezary syndrome and anasarca, revealing a nephrotic syndrome caused by a minimal change nephropathy associated with immunoglobulin A (IgA) deposits. Scarce literature described rare cases associating these two entities (nephrotic syndrome and nephropathy). However, the nephrotic syndrome was delayed from disease onset, secondary to immunosuppressive treatment of SS, or due to the weaning of SS therapy. Thus, the direct link between the glomerular lesion and the cutaneous lymphoma was difficult to establish. However, the synchronous occurrence of both SS and glomerulopathy in our patient, along with Sezary cells in both urines (urinary cytology) and biopsy, and resolution of nephropathy after treatment of SS, support the likely attributability of SS in glomerulopathy.

CONCLUSION

Practitioners must acknowledge the possible occurrence of glomerular involvement in SS.

Novel therapeutic approaches for cutaneous T cell lymphomas

Introduction: Cutaneous T-cell lymphoma (CTCL) is a rare non-Hodgkin's lymphoma, characterized by malignant T cells infiltrating the skin. CTCL exhibits vast heterogeneity which complicates diagnosis and therapeutic strategies. Current CTCL treatment includes skin-directed therapies (such as topical corticosteroid, topical mechlorethamine, topical bexarotene, ultraviolet phototherapy and localized radiotherapy), total skin electron beam therapy and systemic therapies. Elucidation of molecular and signaling pathways underlying CTCL pathogenesis leads to identification of innovative and personalized treatment schemes.Areas covered: The authors reviewed the molecular and immunological aspects of CTCL with special focus on Mycosis Fungoides (MF), Sézary Syndrome (SS) and associated systemic treatment. A literature search was conducted in PubMed and Web of Science for peer-reviewed articles published until November 2020. Novel treatment approaches including retinoids, targeted therapies, immune checkpoint and JAK/STAT inhibitors, histones deacetylase (HDAC) and mTOR inhibitors as well as proteasome inhibitors, are discussed as potential therapeutic tools for the treatment of CTCL.Expert opinion: Novel therapeutic agents exhibit potential beneficial effects in CTCL patients of high need for therapy such as refractory early stage cutaneous and advanced stage disease. Therapeutic schemes employing a combination of novel agents with current treatment options may prove valuable for the future management of CTCL patients.

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.

Efficient Therapeutic Delivery by a Novel Cell-Penetrating Peptide Derived from Acinus

In this study, we have identified a novel cell-penetrating sequence, termed hAP10, from the C-terminus of the human protein Acinus. hAP10 was able to efficiently enter various normal and cancerous cells, likely through an endocytosis pathway, and to deliver an EGFP cargo to the cell interior. Cell penetration of a peptide, hAP10DR, derived from hAP10 by mutation of an aspartic acid residue to an arginine was dramatically increased. Interestingly, a peptide containing a portion of the heptad leucine repeat region domain of the survival protein AAC-11 (residues 377–399) fused to either hAP10 or hAP10DR was able to induce tumor cells, but not normal cells, death both ex vivo on Sézary patients’ circulating cells and to inhibit tumor growth in vivo in a sub-cutaneous xenograft mouse model for the Sézary syndrome. Combined, our results indicate that hAP10 and hAP10DR may represent promising vehicles for the in vitro or in vivo delivery of bioactive cargos, with potential use in clinical settings.

Highly cytotoxic natural killer cells are associated with poor prognosis in patients with cutaneous T-cell lymphoma

Paradoxically higher NK-cell activity in CTCL patients is associated with increased expression of phosphorylated STAT5. These highly effective NK cells are associated with poor prognosis in patients with leukemic CTCL.

Nail Changes in Sézary Syndrome: A Single-Center Study and Review of the Literature

Background:

The onychodystrophies associated with Sézary syndrome (SzS) have rarely been described in the literature. We performed a retrospective analysis of SzS patients at a single institution and compared our data with previous publications.

Objectives:

The objectives of this study were to identify and describe the most frequent nail alterations in patients with SzS.

Methods:

A retrospective analysis was performed with some prospective observations at the University of Pittsburgh from 1989 to 2017.

Results:

We identified 54 patients with SzS out of 535 patients with cutaneous T-cell lymphoma. Nineteen patients with SzS had photos of their nail. All those patients exhibited some type of onychodystrophy. The most common types were paronychia (63.2%; 12/19), leukonychia (42.1%; 8/19), onycholysis (42.1%; 8/19), trachyonychia (31.6%; 6/19), and subungual hyperkeratosis (26.3; 5/19). Cluster analysis of our data in comparison with published data on the psoriatic nails indicated that while leukonychia, onycholysis, subungual hyperkeratosis, and nail discoloration were frequently observed in psoriasis, onychauxis, anonychia, distal notching, and onychoschizia occurred more commonly in patients with SzS.

Conclusions:

The most common nail manifestations in SzS patients included paronychia, leukonychia, and onycholysis. The nail manifestations in SzS patients appeared to be heterogeneous, while onychauxis, anonychia, distal notching, and onychoschizia seem to be specific to SzS in comparison with psoriasis.

Preclinical Targeting of MicroRNA-214 in Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphomas (CTCLs) are a family of primary extranodal lymphomas of mature CD4⁺, skin-homing or skin-resident T cells. In a significant fraction of patients with CTCL, the neoplastic CD4⁺ lymphocytes acquire extracutaneous tropism, and with disease progression, they disseminate to the lymph nodes, peripheral blood, and visceral organs. MicroRNA (miR)-based therapies are a newly emerging strategy for many types of diseases, including cancers. CTCL represents one of the disease indications for a clinical trial of miR inhibitor therapy, supporting further investigation of epigenetic dysregulation and miR-driven oncogenesis in this disease. In this study, we interrogated an aberrant miR-based regulatory network that operates in malignant CD4⁺ T cells and identified potential targets of therapy. We show that miR-214 levels are significantly higher in purified CD4⁺ neoplastic T cells from patients with CTCL than from healthy donors. We then show that antagomiR-214 treatment of IL-15 transgenic mice with spontaneous, miR-214-overexpressing CTCL leads to significant decrease in disease severity using multiple validated clinical and histological endpoints, compared with scrambled control-treated IL-15 transgenic CTCL mice. Mechanistically, we show that aberrantly expressed TWIST1 and BET protein BRD4 cooperate to drive miR-214 expression in CTCL cell lines and in samples from patients with CTCL and that treatment with BRD4 inhibitor JQ1 leads to down-regulation of miR-214. Based on both in vitro and in vivo data, we propose that the TWIST1/BRD4/miR-214 regulatory loop is an important, targetable, oncogenic pathway in CTCL.

MicroRNAs in Cutaneous T-Cell Lymphoma: The Future of Therapy

MicroRNAs (miRs) are small, noncoding RNAs with numerous cellular functions. With advancing knowledge of the many functions of miRs in cancer pathogenesis, there is emerging interest in miRs as therapeutic targets in cancers. One disease that poses an intriguing model for miR therapy is cutaneous T-cell lymphoma, a rare disease featuring malignant CD4⁺ T cells that proliferate in the skin. The hallmark of cutaneous T-cell lymphoma progression is epigenetic dysregulation, with aberrant miR levels being a common feature. This review aims to summarize the rapidly emerging advances in the development of miR-based therapies in cancers, with a special emphasis on CTCL.

Blood and skin-derived Sezary cells: differences in proliferation-index, activation of PI3K/AKT/mTORC1 pathway and its prognostic relevance

Sézary syndrome (SS) is a rare and aggressive variant of Cutaneous T-Cell Lymphoma characterized by neoplastic distribution mainly involving blood, skin, and lymph-node. Although a role of the skin microenvironment in SS pathogenesis has long been hypothesized, its function in vivo is poorly characterized. To deepen this aspect, here we compared skin to blood-derived SS cells concurrently obtained from SS patients highlighting a greater proliferation-index and a PI3K/AKT/mTORC1 pathway activation level, particularly of mTOR protein, in skin-derived-SS cells. We proved that SDF-1 and CCL21 chemokines, both overexpressed in SS tissues, induce mTORC1 signaling activation, cell proliferation and Ki67 up-regulation in a SS-derived cell line and primary-SS cells. In a cohort of 43 SS cases, we observed recurrent copy number variations (CNV) of members belonging to this cascade, namely: loss of LKB1 (48%), PTEN (39%) and PDCD4 (35%) and gains of P70S6K (30%). These alterations represent druggable targets unraveling new therapeutic treatments as metformin here evaluated in vitro. Moreover, CNV of PTEN, PDCD4, and P70S6K, evaluated individually or in combination, are associated with reduced survival of SS patients. These data shed light on effects in vivo of skin-SS cells interaction underlying the prognostic and therapeutic relevance of mTORC1 pathway in SS.

Diminished microRNA-29b level is associated with BRD4-mediated activation of oncogenes in cutaneous T-cell lymphoma

MicroRNA (miRNA) dysregulation is a hallmark of cutaneous T-cell lymphoma (CTCL), an often-fatal malignancy of skin-homing CD4⁺ T cells for which there are few effective therapies. The role of microRNAs (miRs) in controlling epigenetic modifier-dependent transcriptional regulation in CTCL is unknown. In this study, we characterize a novel miR dysregulation that contributes to overexpression of the epigenetic reader bromodomain-containing protein 4 (BRD4). We used patient CD4⁺ T cells to show diminished levels of miR-29b compared with healthy donor cells. Patient cells and miR-29b^-/- mouse cells revealed an inverse relationship between miR-29b and BRD4, the latter of which is overexpressed in these cells. Chromatin immunoprecipitation and sequencing analysis revealed increased genome-wide BRD4 occupancy at promoter and enhancer regions in CD4⁺ T cells from CTCL patients. The cumulative result of BRD4 binding was increased expression of tumor-associated genes such as NOTCH1 and RBPJ, as well as the interleukin-15 (IL-15) receptor complex, the latter enhancing IL-15 autocrine signaling. Furthermore, we confirm the in vivo relevance of this pathway in our IL-15 transgenic mouse model of CTCL by showing that interference with BRD4-mediated pathogenesis, either by restoring miR-29b levels via bortezomib treatment or by directly inhibiting BRD4 binding via JQ1 treatment, prevents progression of CTCL. We describe a novel oncogenic pathway featuring IL-15, miR-29b, and BRD4 in CTCL and suggest targeting of these components as a potentially effective therapy for CTCL patients.

Multidisciplinary Management of Mycosis Fungoides/Sézary Syndrome

PURPOSE OF REVIEW

Diagnosis and management of mycosis fungoides and Sézary syndrome (MF/SS) require accurate clinicopathological correlation and a multidisciplinary approach. We reviewed major advances in the field regarding diagnostic and prognostic tools as well as skin-directed therapies (SDTs) and systemic agents for MF/SS published in the past 2 years.

RECENT FINDINGS

Improved technology (T-cell receptor high-throughput sequencing) and increased multicenter collaboration (Cutaneous Lymphoma International Consortium) have led to diagnostic/prognostic advances. Concurrently, numerous genomic studies have enhanced understanding of disease pathogenesis. Advances in SDTs include topical resiquimod, a novel potent Toll-like receptor (TLR) agonist; consensus CTCL phototherapy guidelines; and use of low-dose radiation therapy. Novel systemic therapies for advanced disease of note include targeted antibody drug conjugates (brentuximab vedotin), immune checkpoint inhibitors, and allogeneic hematopoietic stem cell transplantation (HSCT). Our "toolbox" to diagnose and treat the spectrum of MF/SS continues to expand. Further characterization of genomic data going forward will enable a rational approach to selecting and combining therapies to improve patient care.

CD4-Positive T-Cell Large Granular Lymphocytosis Mimicking Sezary Syndrome in a Patient With Mycosis Fungoides

A white woman aged 65 years presented with a macular, nonscaly, nonpruritic, erythematous lesion on her right breast. Test results revealed histological features similar to lichenoid dermatitis and early-phase primary cutaneous T-cell lymphoma with a subtype of mycosis fungoides (MF). Despite topical therapy with steroids, her skin disease continued to progress, so she underwent polymerase chain reaction and gene mutation testing. Two missense mutations were detected. The overall findings supported a diagnosis of co-occurring, CD4-positive large granular lymphocytosis and stage IA MF. The patient continued to receive topical steroids and maintenance phototherapy, and her skin lesions completely resolved after 14 weeks of therapy. Approximately 5 years after her initial presentation, she was free of symptoms, cytopenia, and no skin lesions were present. CD4-positive, large granular lymphocytosis was persistent. This patient case - to our knowledge, the first of its kind - posed dilemmas of a diagnostic and therapeutic nature. Correctly staging the lymphoma helped to aid the diagnosis and can help prevent patients similar to the one in this case from receiving unnecessary therapy.