Management of refractory early-stage cutaneous T-cell lymphoma

Leveraging nuclear receptor mediated transcriptional signaling for drug discovery: Historical insights and current advances

Nuclear receptors (NRs) are ligand-activated transcription factors that regulate gene expression in response to physiological signals, such as hormones and other chemical messengers. These receptors either activate or repress the transcription of target genes, which in turn promotes or suppresses physiological processes governing growth, differentiation, and homeostasis. NRs bind to specific DNA sequences and, in response to ligand binding, either promote or hinder the assembly of the transcriptional machinery, thereby influencing gene expression at the transcriptional level. These receptors are involved in a wide range of pathological conditions, including cancer, metabolic disorders, chronic inflammatory diseases, and immune system-related disorders. Modulation of NR function through targeted drugs has shown therapeutic benefits in treating such conditions. NR-targeted drugs, which either completely or selectively activate or block receptor function, represent a significant class of clinically valuable therapeutics. However, the pathways of NR-mediated gene expression and the resulting physiological effects are complex, involving crosstalk between various biomolecular components. As a result, NR-targeted drug discovery is challenging. With improved understanding of how NRs regulate physiological functions and deeper insights into their molecular structure, the process of NR-targeted drug discovery has evolved. While many traditional NR-targeting drugs are associated with side effects of varying severity, new drug candidates are being designed to minimize these adverse effects. Given that NR activity varies according to the tissue in which they are expressed and the specific isoform that is activated or repressed, achieving selectivity in targeting specific tissues and isoform classes may help reduce systemic side effects. In a recent breakthrough, the isoform-selective, hepato-targeted thyroid hormone-β agonist, Resmetirom (marketed as Rezdiffra), was approved for the treatment of non-alcoholic steatohepatitis. This chapter explores the structural and mechanistic principles guiding NR-targeted drug discovery and provides insights into recent developments in this field.

Trial watch: FDA-approved Toll-like receptor agonists for cancer therapy

Toll-like receptors (TLRs) have first been characterized for their capacity to detect conserved microbial components like lipopolysaccharide (LPS) and double-stranded RNA, resulting in the elicitation of potent (innate) immune responses against invading pathogens. More recently, TLRs have also been shown to promote the activation of the cognate immune system against cancer cells. Today, only three TLR agonists are approved by FDA for use in humans: the bacillus Calmette-Guérin (BCG), monophosphoryl lipid A (MPL) and imiquimod. BCG (an attenuated strain of Mycobacterium bovis) is mainly used as a vaccine against tuberculosis, but also for the immunotherapy of in situ bladder carcinoma. MPL (derived from the LPS of Salmonella minnesota) is included in the formulation of Cervarix®, a vaccine against human papillomavirus-16 and -18. Imiquimod (a synthetic imidazoquinoline) is routinely employed for actinic keratosis, superficial basal cell carcinoma, and external genital warts (condylomata acuminata). In this Trial Watch, we will summarize the results of recently completed clinical trials and discuss the progress of ongoing studies that have evaluated/are evaluating FDA-approved TLR agonists as off-label medications for cancer therapy.

Classification and Treatment of Rare and Aggressive Types of Peripheral T-Cell/Natural Killer-Cell Lymphomas of the Skin

Background

The classification of cutaneous lymphomas has been contentious. Two major competing classifications were the World Health Organization (WHO) and the European Organization for Research and Treatment of Cancer (EORTC). The principal authors met for a consensus meeting resulted in a combined classification called WHO-EORTC Classification of Cutaneous Lymphoma.

Methods

We review the classification of “mature” or peripheral T-cell lymphoma (PTCL) with high predilection to the skin as published by the WHO-EORTC. We also highlight new information and changes from the previous classifications of cutaneous PTCL according to the WHO classification or the EORTC classification. Finally, the salient findings are compared with similar-looking nodal PTCLs with a high frequency of skin involvement.

Results

This review focuses on a rare group of cutaneous PTCLs other than mycosis fungoides or its variants. Changes from the previous classifications are discussed, and the rare group of nodal PTCLs with high predilection to the skin are presented. The salient findings, diagnostic features, and treatments are included, along with summary tables and clinical-histopathologic images.

Conclusions

This review may serve as a guide for hematologists, oncologists and dermatologists in the diagnosis and management of these rare, aggressive, and often difficult to diagnose lymphomas. Although cutaneous lymphomas are morphologically identical to systemic lymphomas, the former behave differently, require divergent management, and should be recognized as separate entities. The consensus WHO-EORTC classification presents unified terminology and definitions to promote conformity in diagnosing and treating these cases, to foster a multidisciplinary approach to these often-obscure diseases, and to lead to more advances in identifying molecular targets specific to these entities.

Synergistic enhancement of cellular immune responses by the novel Toll receptor 7/8 agonist 3M-007 and interferon-γ: implications for therapy of cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma (CTCL) is responsive at all stages to immunotherapy. We determined whether a novel agonist for Toll-like receptor (TLR) 7/8 (3M-007) combined with either interferon-γ (IFN-γ) or interleukin-15 (IL-15) would enhance patients' immune responses in vitro. Our data demonstrate that IFN-γ or IL-15 in combination with 007 significantly increases patients' natural killer (NK) cytolytic activity against CTCL tumor cell lines and synergistically induces dendritic cell cytokines, compared to 007 alone. Microarray studies of gene expression of patients' peripheral blood mononuclear cells (PBMCs) primed with IFN-γ followed by stimulation with 007 identified significant up-regulation of the expression of IL-12 p35 (α-chain), IL-12 p40 (β-chain), and nine IFN-α genes. Importantly, the underlying mechanism of increased levels of IFN-α and IL-12 from combined treatment appears to involve IFN regulatory factor 8 (IRF-8). These results further support our hypothesis that combinations of biological modifiers activating different arms of the immune system may provide significant therapeutic benefits for patients with advanced CTCL.

[Cutaneous cytotoxic T-cell lymphoma]

Cutaneous cytotoxic T-cell lymphoma is a rare variant of cutaneous T-cell lymphoma, which shows immunoreactivity for CD56+. We report on an 83-year old woman with numerous skin infiltrates and nodules mainly on her face and trunk. Histopathologic criteria lead to the diagnosis of cutaneous cytotoxic T-cell lymphoma. Bexarotene was not tolerated because of cardiac insufficiency, but treatment with methotrexate (7.5 mg once weekly) led to prompt regression of all lesions.

Non-surgical treatments of primary, non-melanoma eyelid malignancies: a review

The diagnosis and management of periocular cutaneous malignancies are essential components of an ophthalmologist's practice. Skin cancers comprise nearly one-third of newly diagnosed malignancies. Furthermore, the incidence of skin cancer appears to be increasing. Multiple treatment modalities exist for periocular cutaneous malignancy. Surgical extirpation, often with the combined expertise of a Mohs micrographic surgeon, is typically the first line therapy and is often curative in the periocular region, depending on a variety of factors, including tumour histology, specific location, depth of invasion and surgical technique. However, there are instances where a less invasive, non-surgical treatment option is warranted, including patients who are poor surgical risks or those with diffuse disease. The purpose of this article is to review the literature and describe the non-surgical treatment options, indications and efficacies for non-melanoma primary eyelid malignancies.

Host and donor immune responses contribute to antiviral effects of amotosalen-treated donor lymphocytes following early posttransplant cytomegalovirus infection

We have previously shown that amotosalen-treated splenocytes rescued allorecipients from a lethal dose of mouse CMV (MCMV) administered on day 0 in experimental parent C57BL/6-->CB6F1 allogeneic bone marrow transplant. In this study, we investigated the mechanism of antiviral activity of amotosalen-treated donor splenocytes when sublethal MCMV infections were administered 7 days posttransplant. Recipients of 3 x 10(6) untreated splenocytes were used as control. Following MCMV infection, recipients of untreated splenocytes had 40% early mortality due to acute graft-vs-host disease compared with no deaths among recipients of 10 x 10(6) treated splenocytes. However, recipients of both types of donor splenocytes effectively cleared MCMV from their liver. Like the untreated CD8(+) T cells, amotosalen-treated CD8(+) T cells equally retained their in vivo CTL activity against MCMV early peptide-pulsed targets and expressed similar levels of granzyme B within 11 days of infection. In contrast to full donor chimerism in recipients of untreated splenocytes, recipients of amotosalen-treated splenocytes showed mixed chimerism with both donor spleen- and host-derived anti-MCMV CD8(+) T cells in their blood and lymphoid organs, with significantly higher numbers of host-derived CD4(-)CD8(-) (double negative) T cells in the spleens of recipients of treated splenocytes compared with the recipients of untreated splenocytes. Additionally, recipients of amotosalen-treated splenocytes had lower levels of serum IFN-gamma and TNF-alpha in response to MCMV infection compared with untreated recipients. Thus, adoptive immunotherapy with treated T cells is a novel therapeutic approach that facilitates hematopoietic engraftment and permits antiviral immunity of both donor and host T cells without graft-vs-host disease.