GATA-3-dependent Gene Transcription is Impaired upon HDAC Inhibition

PURPOSE

Many peripheral and cutaneous T-cell lymphoma (CTCL) subtypes are poorly responsive to conventional chemotherapeutic agents and associated with dismal outcomes. The zinc finger transcription factor GATA-3 and the transcriptional program it instigates are oncogenic and highly expressed in various T-cell neoplasms. Posttranslational acetylation regulates GATA-3 DNA binding and target gene expression. Given the widespread use of histone deacetylase inhibitors (HDACi) in relapsed/refractory CTCL, we sought to examine the extent to which these agents attenuate the transcriptional landscape in these lymphomas.

EXPERIMENTAL DESIGN

Integrated GATA-3 chromatin immunoprecipitation sequencing and RNA sequencing analyses were performed in complementary cell line models and primary CTCL specimens treated with clinically available HDACi.

RESULTS

We observed that exposure to clinically available HDACi led to significant transcriptional reprogramming and increased GATA-3 acetylation. HDACi-dependent GATA-3 acetylation significantly impaired both its ability to bind DNA and transcriptionally regulate its target genes, thus leading to significant transcriptional reprogramming in HDACi-treated CTCL.

CONCLUSIONS

Beyond shedding new light on the mechanism of action associated with HDACi in CTCL, these findings have significant implications for their use, both as single agents and in combination with other novel agents, in GATA-3-driven lymphoproliferative neoplasms.

A case report of acute promyelocytic leukemia with mycosis fungoides

RATIONALE

Acute promyelocytic leukaemia (APL) is a rare subtype of acute myelogenous leukaemia. With advances in treatment regimens, namely, introduction of all-trans-retinoicacid, outcomes have drastically improved, its side effects should not be ignored. Mycosis fungoides is one of the side effects of all-trans-retinoicacid treatment, but it may also be a clinical manifestation before disease progression. However, it rarely appears and is easily overlooked. This leads to being easily misled during the treatment process, affecting the treatment plan, and resulting in adverse consequences. Therefore, early identification and judgment can not only provide appropriate treatment options, but also prevent and treat further disease progression.

PATIENT CONCERNS

The patient was hospitalized for pancytopaenia. After completing the examination, the patient was finally diagnosed with acute promyelocytic leukaemia (acute myelogenous leukaemia-M3). We administered tretinoin and arsenous acid. Evaluation of the treatment effect on the 7th day after chemotherapy showed that the bone marrow morphology showed complete remission. After the second course of chemotherapy, the patient developed red miliary macular papules, which gradually worsened. After completing relevant inspections, Considering that the cases was complicated with skin mycosis fungoides, the patient was treated with budesonide ointment and methylprednisolone as chemotherapy.

DIAGNOSES

Upon examination, the patient was initially diagnosed with acute promyelocytic leukaemia. Evaluation of the treatment effect on the 7th day after chemotherapy showed that the bone marrow morphology showed complete remission. After the second course of chemotherapy, we discovered the patient was diagnosed with skin mycosis fungoides.

INTERVENTIONS

Systemic chemotherapy is first given when a patient was diagnosed with acute promyelocytic leukaemia. After the patient happened skin mycosis fungoides, We have adjusted the treatment plan and supplemented it with other treatment plans based on the original chemotherapy, After 2 months of treatment, his condition gradually improved.

OUTCOMES

All-trans-retinoicacid in the treatment of APL must be given attention because mycosis fungoides should not only be distinguished from infectious diseases but also be further assessed with regard to disease progression and metastasis.

LESSONS

Acute promyelocytic leukemia needs to be treated with arsenic trioxide. All-trans-retinoicacid in the treatment of APL must be given attention mycosis fungoides. Early diagnosis can guide accurate treatment, which is of great help in alleviating the pain of patients and improving the cure rate.

Pneumocystis jirovecii Pneumonia in a Patient With Localized Mycosis Fungoides Not Receiving Immunosuppressive Treatment

Pneumocystis jirovecii pneumonia (PCP) is the most common opportunistic infection in patients with human immunodeficiency virus (HIV), but it may develop in patients without HIV, whose immune system is suppressed by anticancer or immunosuppressive agents even when indicating normal counts of CD4+ T cells. Mycosis fungoides (MF) is a primary cutaneous T-cell lymphoma, which is believed not to cause immunosuppressive conditions unless it develops leukosis or metastasis or is treated with anticancer drugs or systemic immunosuppressants. Here, we report a case of PCP in a patient with localized MF not receiving immunosuppressive treatment. The patient, a woman in her 70s, presented with persistent dyspnea. High-resolution computed tomography (HRCT) showed diffuse ground-glass opacities in both lungs. Bronchoalveolar lavage fluid was positive for P. jirovecii. Moreover, the cytomegalovirus antigenemia test was positive, whereas tests for anti-HIV and antihuman T-cell lymphotropic virus antibodies were negative. The patient was treated with trimethoprim-sulfamethoxazole, prednisolone, and ganciclovir, which gradually improved the symptoms and diminished diffuse ground-glass opacities on HRCT. This case exemplifies a rare presentation of PCP with mild MF that was not treated with chemotherapy or immunosuppressants. The possible mechanisms for the development of PCP are discussed.

Cutaneous Intravascular CD-30-Positive Anaplastic Large Cell Lymphoma: A Case Report and Literature Review

Intravascular cutaneous anaplastic large cell lymphoma (ALCL) is an extremely rare non-Hodgkin lymphoma that proliferates in the lumen of small blood vessels and has a propensity to manifest in the skin. Most reported cases of intravascular lymphoma described in the literature are of large B-cell lymphomas, making T-cell lymphomas incredibly rare. As such, we present the case of an 87-year-old male with primary cutaneous intravascular anaplastic large T-cell lymphoma that initially presented with an erythematous, subcutaneous nodule on the right mid-abdomen. We report the immunohistochemical results showing lymphoma cells staining positively for CD3 and CD30 and lacking expression of anaplastic lymphoma kinase, pan-cytokeratin, CD10, CD20, and SOX10. We also review and compare previously reported cases of intravascular ALCL with primary cutaneous involvement.

Cutaneous T-cell Lymphoma Progression: A Potential Dupilumab Pitfall

Dupilumab is a monoclonal antibody inhibiting key drivers in the inflammatory signaling cascade. It has been considered a saving grace for many patients suffering from severe atopic dermatitis and has quickly become a widespread treatment option for many inflammatory pathologies. However, recent reports have linked dupilumab with exacerbating symptoms and accelerated disease progression of cutaneous T-cell lymphoma (CTCL). This report presents the case of a 60-year-old African American female who was diagnosed with CTCL three months after her initial treatment with dupilumab for presumed atopic dermatitis. An appreciation of this unique relationship, as well as the morphological differences seen in patient presentation, is important for physicians to better guide timely diagnoses while working to uncover the true relationship between dupilumab and CTCL.

Overcoming Chemotherapy Resistance in Cutaneous T-Cell Lymphoma: A Successful Case of High-Dose Radiotherapy Management

The management of refractory cutaneous T-cell lymphoma (CTCL) is challenging and requires a multimodal approach. Radiotherapy is one of the treatment options used in managing CTCL, particularly for localized disease or as a palliative measure to control symptoms in advanced cases. The rarity of the disease makes it difficult to conduct extensive clinical trials and gather sufficient data on the most effective treatment approaches. Lymphocytes are among the most sensitive cells to radiation's damaging effects. Because of this sensitivity, radiation therapy can be an effective treatment. This case illustrates the efficacy of radiotherapy and its potential as an effective treatment alternative for a severe and resistant CTCL to systemic therapy in a 61-year-old Moroccan patient. The patient underwent curative high-dose radiation therapy, utilizing three-dimensional conformal radiation therapy. At the 19-month follow-up post-radiotherapy, no evidence of local recurrence, either clinically or radiologically, was observed, and the patient maintained a good quality of life with unrestricted mobility of his arm.

Cutaneous T-cell lymphoma developing in surgical scars post cardiac surgery: A case study

Cutaneous T-cell lymphomas are a class of non-Hodgkin lymphomas characterized by the infiltration of malignant T cells into the skin. Their precise pathogenesis remains incompletely understood, but persistent and specific antigen stimulation of skin-homing CD4+ memory T cells by external or internal factors, combined with an inflammatory cytokine-rich tissue microenvironment, may be critical in the development of cutaneous T-cell lymphomas. We present herein a case of primary cutaneous T-cell lymphoma arising in two surgical scars that developed 6 months post-operatively and were successfully treated with external beam radiotherapy. This case highlights the notion that primary cutaneous T-cell lymphoma can develop locally at the site of injury/foreign body within a relatively short time post trauma/surgery. This work contributes to the literature of cutaneous T-cell lymphomas arising after a trauma, surgery, or a foreign body.

Advanced stage cutaneous T-cell lymphoma treated with high-dose external beam radiation therapy: A case report

INTRODUCTION

The treatment for advanced-stage or refractory cutaneous T-cell lymphoma (CTCL) is largely palliative. Due to the rarity of the disease, there are few randomized controlled trials and large-scale prospective studies. Therefore, the treatment of advanced-stage CTCL remains challenging.

PATIENT CONCERNS AND DIAGNOSIS

A 64-years-old man who had received narrowband UVB phototherapy for several years presented with a generalized rash with widespread polycyclic erosions and painful ulcers on his hands and feet. We restaged him as stage III CTCL.

INTERVENTIONS AND OUTCOMES

He was treated with high-dose radiation for curative purposes and 3-dimensional conformal radiation therapy to both hands and feet. At the 2-year follow-up after the end of radiotherapy, the irradiated skin had recovered to normal soft, smooth skin with localized fibrosis and hypopigmented skin. He reported an excellent quality of life, and his hands and feet were free to move.

CONCLUSION

CTCL at an advanced stage could require dose escalation with local radiotherapy for curative purposes. High-dose 3-dementional conformal radiation therapy could be effective and has tolerable toxicities.

Primary Cutaneous Anaplastic Large Cell Lymphoma With Gastric Metastasis

Primary cutaneous anaplastic large cell lymphoma (PCALCL) is a subtype of non-Hodgkin lymphoma (NHL) that is localized to the skin. Disseminated disease is rare, and visceral organ involvement is even more so. We report a unique case of PCALCL with gastric metastasis. A 75-year-old man with a history of cutaneous left lower extremity PCALCL status post radiation therapy initially presented with abdominal pain and was found to have diffuse celiac axis and retroperitoneal lymphadenopathy. Endoscopy, initially done to biopsy an involved lymph node (LN), demonstrated a friable gastric nodular lesion with telangiectasias. Biopsy of the lesion and LN revealed anaplastic large cell lymphoma, identical in pathology to the known skin lesion. The patient was treated with systemic chemotherapy with a good response. PCALCL has been thought of as a localized malignancy with a good prognosis and low potential for extracutaneous spread. To our knowledge, this is the first instance of metastatic PCALCL involving the stomach.

Response to Chlormethine/Mechlorethamine gel Maintenance Treatment Regimen in Patients With Mycosis Fungoides: A Single-center Retrospective Study

BACKGROUND

Mycosis fungoides (MF), the most common subtype of Cutaneous T-cell lymphomas, is caused by malignant T-cell proliferations in the skin that can invade blood, lymph nodes, or viscera. Currently, data on efficacy of maintenance therapies in MF are lacking. We developed a unique protocol to use chlormethine/mechlorethamine 0.016% gel formulation as maintenance regimen for MF patients in remission.

PURPOSE

To determine progression-free survival and efficacy of chlormethine/mechlorethamine as maintenance and active treatment regimens for MF.

MATERIALS AND METHODS

A retrospective review of MF patients seen at Thomas Jefferson University from 2012 to 2020 was conducted. Patients of all stages treated with chlormethine/mechlorethamine as maintenance or active treatment with 2 consecutive mSWATs (modified Severity Weighted Assessment Tool) documented were included. Treatment outcomes were assessed by change in mSWAT and progression-free survival. Dermatology Life Quality Index surveys before and after treatment were analyzed.

RESULTS

Of 186 MF patients, 44 met inclusion criteria. Patients on maintenance therapy had a 65.22% progression-free survival rate with median time to progression of 29.45 months. By-time analysis for responders on active and maintenance treatment showed an increased response over time. Peak responses were seen at last mSWAT recorded. Both cohorts experienced improved quality-of-life scores from initiation to discontinuation of chlormethine/mechlorethamine.

CONCLUSION

Patients on maintenance and active chlormethine/mechlorethamine treatment regimens demonstrated improvement in mSWAT and quality-of-life. Chlormethine/mechlorethamine treatment showed progression-free survival for a median of 29.45 months, indicating this therapy may be an effective maintenance regimen.

Factors Associated With In-Hospital Mortality in Mycosis Fungoides Patients: A Multivariable Analysis

Background Mycosis fungoides (MF) is the most common form of cutaneous T-cell lymphoma (CTCL). Although it often has an indolent course, it can progress to more aggressive CTCL forms. There is sparse data in current literature describing specific clinical factors associated with in-hospital mortality in mycosis fungoides patients. An understanding of patients at greatest risk for in-hospital mortality can aid in developing recommendations for prophylaxis and empirical management. Aim We aim to characterize factors associated with in-hospital mortality in MF patients. Materials and methods The Nationwide Emergency Department Sample (NEDS) was queried for MF cases from 2006 to 2015. Baseline demographic and hospital characteristics were stratified based on survival outcomes. Multivariable logistic regression was used to identify factors associated with in-hospital mortality. Results A total of 57,665 patients with MF presenting to the ED between 2006 and 2015 were identified. Sézary syndrome, sepsis, and advanced age were associated with MF in-hospital mortality, while female sex was inversely associated. There was a downtrend in in-hospital mortality among MF patients presenting to the ED from 2006 to 2015. Conclusions Our study highlights factors crucial for risk-stratification for hospitalized MF patients.

MicroRNA Regulation of T-Cell Exhaustion in Cutaneous T Cell Lymphoma

Cutaneous T cell lymphoma (CTCL) is characterized by a background of chronic inflammation, where malignant CTCL cells escape immune surveillance. To study how microRNAs (miRs) regulate T-cell exhaustion, we performed miR sequencing analysis, qRT-PCR, and in situ hybridization on 45 primary CTCL samples, three healthy skin samples, and CTCL cell lines, identifying miR-155-5p, miR-130b-3p, and miR-21-3p. Moreover, miR-155-5p, miR-130b-3p, and miR-21-3p positively correlated with immune checkpoint gene expression in lesional skin samples and were enriched in the IL-6/Jak/signal transducer and activator of transcription signaling pathway by gene set enrichment analysis. Further gene sequencing analysis showed decreased mRNA expression of the major negative regulators of Jak/signal transducer and activator of transcription signaling: SOCS, PIAS, and PTPN. Transfection of MyLa and HuT78 cells with anti-miR-155-5p, anti‒miR-21-3p, and anti‒miR-130b revealed a considerable increase in SOCS proteins along with a significant decrease in the levels of activated signal transducer and activator of transcription 3 and immune checkpoint surface protein expression as well as decreased cell proliferation. Downregulation of miR-155, miR-130, and miR-21 in CTCL cell lines decreased CTCL cell growth and facilitated CD8⁺ T-cell-mediated cytotoxic activity, with concordant production of IFN-γ and CD107a expression. Our results describe the mechanisms of miR-induced T-cell exhaustion, which provide a foundation for developing synthetic anti-miRs to therapeutically target the tumor microenvironment in CTCL.

Near-infrared photoimmunotherapy for the treatment of skin disorders

INTRODUCTION

Near-Infrared Photoimmunotherapy (NIR-PIT) is a novel molecularly targeted phototherapy. This technique is based on a conjugate of a near-infrared photo-inducible molecule (antibody-photon absorber conjugate, APC) and a monoclonal antibody that targets a tumor-specific antigen. To date, this novel approach has been successfully applied to several types of cancer.

AREAS COVERED

The authors discuss the possible use of NIR-PIT for the management of skin diseases, with special attention given to squamous cell carcinomas, advanced melanomas, and primary cutaneous lymphomas.

EXPERT OPINION

NIR-PIT may be an attractive strategy for the treatment of skin disorders. The main advantage of NIR-PIT therapy is its low toxicity to healthy tissues. Cutaneous lymphocyte antigen is a potential molecular target for NIR-PIT for both cutaneous T-cell lymphomas and inflammatory skin disorders.

Bexarotene: A Rare Cause of Misleading Thyroid Function Tests

Bexarotene is a very rare cause of central hypothyroidism (CH) and its effects have been reported to be dose-dependent; however, the available data in the literature on dose-dependent effects are variable. The standard practice of monitoring thyroid function using thyroid-stimulating hormone (TSH) to adjust levothyroxine (LT4) dose does not apply to bexarotene since it causes CH. In CH, TSH is not reliable. Hence free tetraiodothyronine (fT₄) level is used to monitor and adjust the LT4 dose. We report a case of an 81-year-old Caucasian male with cutaneous T-cell lymphoma (CTCL) who was treated with bexarotene. His pre-treatment TSH was normal at 1.6 µIU/mL (reference range: 0.46-4.68 µIU/mL). Post-bexarotene, the total tetraiodothyronine (T₄) level was within the reference range, but a downward trend was noted. Eventually, total triiodothyronine (T₃) dropped to a low level of 0.61 ng/mL (reference range: 0.97-1.69 ng/mL), and LT4 was initiated. Bexarotene dose was increased, but LT4 was not increased by the primary physician who relied on TSH level, which was low, and hence the existing LT4 dose was maintained. The patient had persistent symptoms of hypothyroidism and, eventually, a diagnosis of CH was made. The symptoms of hypothyroidism improved after normalizing fT₄, with an increase in the LT4 dose. This case represents an example of missed CH due to bexarotene, ­which led to suboptimal LT4 replacement impacting the quality of life for the patient.

Primary Cutaneous CD30+ Anaplastic Large Cell Lymphoma: A Rare Association With Large Plaque Parapsoriasis

Primary cutaneous CD30-positive lymphoproliferative disorders represent the second most common subgroup of cutaneous T-cell lymphomas and include lymphomatoid papulosis, primary cutaneous anaplastic large cell lymphoma, and borderline lesions. Primary cutaneous anaplastic large cell lymphoma is characterized by the presence of solitary or localized nodules or tumors located on the extremities or the cephalic or cervical region. Large plaque parapsoriasis is a chronic inflammatory disorder that associates a high risk of progression to mycosis fungoides. We report a case of CD30+ primary cutaneous anaplastic large cell lymphoma in a patient with a long history of large plaque parapsoriasis.

Pilot Study of a Novel Therapeutic Approach for Refractory Advanced Stage Folliculotropic Mycosis Fungoides

Folliculotropic mycosis fungoides is a variant of cutaneous T-cell lymphoma characterized as having a folliculocentric infiltrate of malignant T cells along with a worse prognosis in comparison to the epidermotropic variants. Patients with advanced forms of folliculotropic mycosis fungoides are often poorly responsive to both skin-directed as well as to systemic therapies. We report here a high response rate using a novel therapeutic regimen combining interferon gamma, isotretinoin in low dose and topical carmustine, and in some cases concomitant skin-directed therapies, among 6 consecutive patients with refractory folliculotropic mycosis fungoides with stages IB through IIIB who had previously failed both topical and systemic therapies. The potential mechanisms of this multimodality approach are discussed.

Multifocal CD4+ Primary Cutaneous Small/Medium Lymphoproliferative Disorder Successfully Treated With Low-Dose Oral Methotrexate: A Case Report

Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder (PCSM-LPD) is a rare indolent disorder often associated with a favourable prognosis. It typically presents as a solitary skin lesion, mainly in the head, neck, or upper trunk region. Multifocal PCSM-LPD is a rare entity, with no standard treatment approaches available. In this article, we present the case of a 56-year-old male patient with multifocal biopsy-proven PCSM-LPD that was treated with methotrexate orally at 10 mg/m² body surface area weekly and successfully achieved full clinical resolution by the 10th week of therapy. A review of the literature indicates the efficacy of combination chemotherapy. However, due to the indolent nature of this disorder and the undesired side effects from combination chemotherapy, our treatment method involved oral methotrexate alone, and it was successful. Oral methotrexate is a potential therapeutic option in the management of multifocal PCSM-LPD and it warrants further investigations.

A single center phase II study of ixazomib in patients with relapsed or refractory cutaneous or peripheral T-cell lymphomas

The transcription factor GATA-3, highly expressed in many cutaneous T-cell lymphoma (CTCL) and peripheral T-cell lymphomas (PTCL), confers resistance to chemotherapy in a cell-autonomous manner. As GATA-3 is transcriptionally regulated by NF-κB, we sought to determine the extent to which proteasomal inhibition impairs NF-κB activation and GATA-3 expression and cell viability in malignant T cells. Proteasome inhibition, NF-κB activity, GATA-3 expression, and cell viability were examined in patient-derived cell lines and primary T-cell lymphoma specimens ex vivo treated with the oral proteasome inhibitor ixazomib. Significant reductions in cell viability, NF-κB activation, and GATA-3 expression were observed preclinically in ixazomib-treated cells. Therefore, an investigator-initiated, single-center, phase II study with this agent in patients with relapsed/refractory CTCL/PTCL was conducted. Concordant with our preclinical observations, a significant reduction in NF-κB activation and GATA-3 expression was observed in an exceptional responder following one month of treatment with ixazomib. While ixazomib had limited activity in this small and heterogeneous cohort of patients, inhibition of the NF-κB/GATA-3 axis in a single exceptional responder suggests that ixazomib may have utility in appropriately selected patients or in combination with other agents.

Phase II study of gemcitabine and bexarotene (GEMBEX) in the treatment of cutaneous T-cell lymphoma

BACKGROUND

Both gemcitabine and bexarotene are established single agents for the treatment of cutaneous T-cell lymphoma (CTCL). We investigated the feasibility and efficacy of combining these drugs in a single-arm phase II study.

METHODS

Cutaneous T-cell lymphoma patients who had failed standard skin-directed therapy and at least one prior systemic therapy were given four cycles of gemcitabine and concurrent bexarotene for 12 weeks. Responders were continued on bexarotene maintenance until disease progression or unacceptable toxicity.

RESULTS

The median age was 65 years, stage IB (n=5), stage IIA (n=2), stage IIB (n=8), stage III (n=8) and stage IVA (n=12), 17 patients were erythrodermic, 17 patients were B1, and 10 patients were both erythrodermic and B1. Thirty (86%) patients completed four cycles of gemcitabine. In all, 80.0% of patients demonstrated a reduction in modified Severity-Weighted Assessment Tool (mSWAT) score although the objective disease response rate at 12 weeks was 31% (partial response (PR) 31%) and at 24 weeks 14% (PR 14%, stable disease (SD) 23%, progressive disease (PD) 54%, not evaluable 9%). Median progression-free survival was 5.3 months and median overall survival was 21.2 months.

CONCLUSION

The overall response rate of the combination did not reach the specified target to proceed further and is lower than that previously reported for gemcitabine as a single agent.

T-cell inhibitors: a bench-to-bedside review

Allergic contact dermatitis is the quintessential example of a delayed-in-time and T-cell-mediated immune response. In the last decade, many of the molecular events required to initiate (or block) such a response have been uncovered. Textbook and journal reviews have emphasized the costimulatory requirements, with less focus on the coinhibitory signals that are of equal importance in understanding this central event of adaptive immunity. To fill this gap, we offer a compendium of discoveries characterizing the ligand-receptor pairs inhibiting T-cell activation and of selected illnesses and therapeutic applications that illuminate their role in health and disease.

The histone deacetylase inhibitors vorinostat and romidepsin downmodulate IL-10 expression in cutaneous T-cell lymphoma cells

BACKGROUND AND PURPOSE

Vorinostat and romidepsin are histone deacetylase inhibitors (HDI), approved for the treatment of cutaneous T-cell lymphoma (CTCL). However, the mechanism(s) by which these drugs exert their anti-cancer effects are not fully understood. Since CTCL is associated with immune dysregulation, we investigated whether these HDI modulated cytokine expression in CTCL cells.

EXPERIMENTAL APPROACH

CTCL cell lines and primary CTCL cells were treated in vitro with vorinostat or romidepsin, or with STAT3 pathway inhibitors. Cell cycle parameters and apoptosis were analysed by propidium iodide and annexin V/propidium iodide staining respectively. Cytokine expression was analysed using QRT-PCR and elisa assays. STAT3 expression/phosphorylation and transcriptional activity were analysed using immunoblotting and transfection/reporter assays respectively.

KEY RESULTS

Vorinostat and romidepsin strongly down-regulated expression of the immunosuppressive cytokine, interleukin (IL)-10, frequently overexpressed in CTCL, at both the RNA and protein level in CTCL cell lines and at the RNA level in primary CTCL cells. Vorinostat and romidepsin also increased expression of IFNG RNA and decreased expression of IL-2 and IL-4 RNA, although to a lesser extent compared to IL-10. Transient exposure to vorinostat was sufficient to suppress IL-10 secretion but was not sufficient to irreversibly commit cells to undergo cell death. STAT3 pathway inhibitors decreased production of IL-10 and vorinostat/romidepsin partially decreased STAT3-dependent transcription without effects on STAT3 expression or phosphorylation.

CONCLUSIONS AND IMPLICATIONS

These results demonstrate that HDI modulate cytokine expression in CTCL cells, potentially via effects on STAT3. Immunomodulation may contribute to the clinical activity of HDI in this disease.

Therapeutic advances in cutaneous T-cell lymphoma

A variety of novel therapeutic modalities have recently become available for patients with cutaneous T cell lymphoma (CTCL). In particular, with recent FDA approvals of the three new agents vorinostat (Zolinza), romidepsin (Istodax), and pralatrexate (Folotyn) CTCL treatment has been transformed. Here, we offer a brief overview of these agents and discuss their place in the spectrum of current therapies for CTCL.

Prognostic significance of the therapeutic targets histone deacetylase 1, 2, 6 and acetylated histone H4 in cutaneous T-cell lymphoma

AIMS

Aberrant histone acetylation has been associated with malignancy and histone deacetylase (HDAC) inhibitors are currently being investigated in numerous clinical trials. So far, the malignancy most sensitive to HDAC inhibitors has been cutaneous T-cell lymphoma (CTCL). The reason for this sensitivity is unclear and studies on HDAC expression and histone acetylation in CTCL are lacking. The aim of this study was to address this issue.

METHODS AND RESULTS

The immunohistochemical expression of HDAC1, HDAC2, HDAC6, and acetylated H4 was examined in 73 CTCLs and the results related to histological subtypes and overall survival. HDAC1 was most abundantly expressed (P < 0.0001), followed by HDAC2; HDAC6 and H4 acetylation were equally expressed. HDAC2 (P = 0.001) and H4 acetylation (P = 0.03) were significantly more common in aggressive than indolent CTCL subtypes. In contrast, no differences were observed for HDAC1 and HDAC6. In a Cox analysis, elevated HDAC6 was the only parameter showing significant influence on survival (P = 0.04).

CONCLUSIONS

High expression of HDAC2 and acetylated H4 is more common in aggressive than indolent CTCL. HDAC6 expression is associated with a favorable outcome independent of the subtype.

Transcriptional modulations by RXR agonists are only partially subordinated to PPARalpha signaling and attest additional, organ-specific, molecular cross-talks

Nuclear hormone receptors (NR) are important transcriptional regulators of numerous genes involved in diverse pathophysiological and therapeutic functions. Following ligand activation, class II NR share the ability to heterodimerize with the retinoid X receptor (RXR). It is established that RXR activators, rexinoids, transactivate several peroxisome proliferator-activated receptor alpha (PPARalpha) target genes in a PPARalpha-dependent manner. We hypothesized that, once activated, RXR might signal through quiescent NR other than PPARalpha, in an organ-specific manner. To study this putative phenomenon in vivo, we developed an array of 120 genes relevant to the class II NR field. The genes were selected using both published data and high-density screenings performed on RXR or PPARalpha agonist-treated mice. Wild-type C57BL/6J and PPARalpha-deficient mice were treated with fenofibrate (PPARalpha activator) or LGD1069 (RXR activator). Using our customized array, we studied the hepatic, cardiac, and renal expression of this panel of 120 genes and compared them in both murine genotypes. The results obtained from this study confirmed the ability of an RXR agonist to modulate PPARalpha-restricted target genes in the liver and the kidney. Furthermore, we show that various organ-specific regulations occurring in both genotypes (PPARalpha +/+ or -/-) are highly indicative of the ability of RXR to recruit other class II NR pathways. Further development of this molecular tool may lead to a better understanding of the permissiveness of class II nuclear receptor dimers in vivo.