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

A novel knockout mouse model to assess the impact of one-copy loss of Hnrnpk in CD4 + T cells in chronically inflamed skin as a prelude to CTCL

Cutaneous T-cell lymphomas (CTCLs), particularly Mycosis fungoides (MF), frequently exhibit deletions and reduced expression of HNRNPK in CD4 + T cells. To enable in vivo studies, we developed a conditional Hnrnpk knockout mouse that thrives, facilitating the investigation of HNRNPK's role in CTCL onset. We generated mice with a floxed Hnrnpk allele, then crossbred them with Cd4CreERT2 mice to generate Hnrnpk flox Cd4CreERT2 mice, all in BL6 background. PCR confirmed the targeted deletion of Hnrnpk in CD4 + T cells after tamoxifen i.p. injection. Skin allergic reactions were induced with oxazolone, and Cre was activated in skin-infiltrating CD4 + T cells using tamoxifen topically after the first allergic skin reaction. The mice exhibited no immediately obvious phenotype. Flow cytometry and histopathological analysis were conducted on blood and skin samples collected throughout the experiment. Following 20 weeks of sustained allergic reactions, inflammation persisted over 20 weeks after challenges ceased, demonstrating early CTCL characteristics such as chronic skin inflammation, CD3 + CD4 + T cell infiltration, and stable peripheral blood parameters. This mouse model provides experimental access to the complex microenvironment and immune responses involved in early inflammatory stages, providing opportunities for further research into the role of HNRNPK in CTCL and the development of effective therapeutic interventions for this challenging malignancy.

Is Kaposi sarcoma a novel comorbidity of cutaneous lymphoma? A systematic review of the literature

BACKGROUND AND OBJECTIVES

Patients with cutaneous lymphomas (CL) are at an increased risk of developing secondary malignancies. This study aimed to assess the frequency of association between CL and Kaposi sarcoma (KS) and to identify factors that may promote the co-occurrence of these two diseases.

PATIENTS AND METHODS

On January 25, 2024, we conducted a systematic search of four electronic medical databases to identify all published cases of KS associated with CL. The clinical course and outcomes of these patients were summarized. For critical appraisal, we applied the JBI Checklist for Case Reports. The study was registered in the PROSPERO database (CRD42022313204).

RESULTS

A total of 40 articles reporting on 45 patients were assessed for eligibility. We included 27 cases in the final analysis (26 cutaneous T-cell lymphomas, 1 cutaneous B-cell lymphoma). In 71% of cases, the diagnosis of CL preceded KS. Nearly half (48%) of the patients had erythrodermic mycosis fungoides or Sézary syndrome. KS lesions were predominantly limited to the skin, with complete remission achieved in 53% of cases.

CONCLUSIONS

The association between KS and CL is rare, limiting our study due to the small sample size and potential reporting bias. Skin-targeted therapies, a restricted T-cell repertoire, and impaired T-cell responses in erythrodermic CTCL patients may contribute to the development of KS.

Therapeutic Targeting of the Janus Kinase/Signal Transducer and Activator of Transcription Pathway in Cutaneous T-Cell Lymphoma

Background/Objectives: Cutaneous T-cell lymphoma (CTCL) is a rare group of non-Hodgkin lymphomas characterized by the clonal expansion of malignant T cells. While current treatments can alleviate symptoms and significant progress has been made in treating leukemic CTCL, a definitive cure remains elusive. Dysregulation of the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway is a key driver of CTCL pathogenesis. As a result, therapeutic strategies targeting JAK/STAT signaling have gained momentum, with the increasing use of JAK inhibitors and other agents that effectively suppress this pathway. These immune-modulating therapies have broad effects on physiological processes, inflammation, and the pathological changes associated with both inflammatory diseases and cancers. Several JAK inhibitors, originally FDA-approved for inflammatory conditions, are now being investigated for cancer treatment. Methods: In this paper, a brief review of the literature on JAK/STAT pathway dysregulation in CTCL is provided, highlighting both clinical and preclinical studies involving JAK inhibitors and other agents that target this pathway. Results: Specifically, we focus on six JAK inhibitors currently under clinical investigation-golidocitinib, ruxolitinib, cerdulatinib, tofacitinib, upadacitinib, and abrocitinib. Additionally, we discuss preclinical studies that explore the mechanisms underlying JAK/STAT pathway inhibition in CTCL. Furthermore, we review reported cases in which CTCL relapsed or emerged following JAK inhibitor treatment. Conclusions: Collectively, these findings support the potential clinical utility of targeting the JAK/STAT pathway in CTCL. However, further research is needed to evaluate safety risks, minimize adverse effects, and optimize these therapeutic strategies.

The Tumor Microenvironment as a Therapeutic Target in Cutaneous T Cell Lymphoma

Cutaneous T cell lymphomas (CTCLs) are a heterogeneous group of non-Hodgkin lymphomas, with mycosis fungoides and Sézary syndrome being the two common subtypes. Despite the substantial improvement in early-stage diagnosis and treatments, some patients still progress to the advanced stage with an elusive underpinning mechanism. While this unsubstantiated disease mechanism coupled with diverse clinical outcomes poses challenges in disease management, emerging evidence has implicated the tumor microenvironment in the disease process, thus revealing a promising therapeutic potential of targeting the tumor microenvironment. Notably, malignant T cells can shape their microenvironment to dampen antitumor immunity, leading to Th2-dominated responses that promote tumor progression. This is largely orchestrated by alterations in cytokines expression patterns, genetic dysregulations, inhibitory effects of immune checkpoint molecules, and immunosuppressive cells. Herein, the recent insights into the determining factors in the CTCL tumor microenvironment that support their progression have been highlighted. Also, recent advances in strategies to target the CTCL tumor micromovement with the rationale of improving treatment efficacy have been discussed.

Non-coding RNAs in the spotlight of the pathogenesis, diagnosis, and therapy of cutaneous T cell lymphoma

Cutaneous T-cell lymphoma (CTCL) is a group of primary and secondary cutaneous malignancies characterized by aberrant T-cells in the skin. Diagnosing CTCL in its early stage can be difficult because of CTCL's ability to mimic benign cutaneous inflammatory skin diseases. CTCL has multiple subtypes with different disease progression and diagnostic parameters despite similar clinical manifestations. The accurate diagnosis and prognosis of a varied range of diseases require the detection of molecular entities to capture the complete footprint of disease physiology. Non-coding RNAs (ncRNAs) have recently been discovered as major regulators of CTCL gene expression. They can affect tumor cell growth, migration, programmed cell death (PCD), and immunoregulation through interactions with the tumor microenvironment (TME), which in turn affect CTCL progression. This review summarizes recent advances in how ncRNAs regulate CTCL cell activity, especially their role in PCD. It also discusses the potential use of ncRNAs as diagnostic and prognostic biomarkers for different subtypes of CTCL. Furthermore, prospective targets and therapeutic approaches influenced by ncRNAs are presented. A better appreciation of the intricate epigenetic landscape of CTCL is expected to facilitate the creation of innovative targeted therapies for the condition.

Hsa_circRNA_101036 aggravates hypoxic-induced endoplasmic reticulum stress via the miR-21-3p/TMTC1 axis in oral squamous cell carcinoma

Objective

Circular RNAs (circRNAs) have been identified as potential biomarkers and therapeutic targets for various types of cancer, including Oral squamous cell carcinoma (OSCC). Hsa_circRNA_101036 was found to function as a cancer suppressor gene in OSCC; however, the underlying regulatory mechanism remains unclear. We investigated the role of hsa_circRNA_101036 in OSCC development and progression and explored its potential as a therapeutic target.

Methods

We performed a bioinformatics analysis and used experimental approaches to investigate the regulatory mechanism of hsa_circRNA_101036. The database StarBase v.2.0 was used to predict potential target-miRNAs of hsa_circRNA_101036. The levels of hsa_circRNA_101036, miR-21-3p, and TMTC2 expression in samples of OSCC cancer tissue (n = 15) and adjacent tissue (n = 15) were determined. We also examined the effects of hsa_circRNA_101036 overexpression on OSCC cell lines by using cell viability, migration, and invasion assays. The proportions of apoptotic cells and the reactive oxygen species (ROS) levels were analyzed by flow cytometry. We also investigated how hsa_circRNA_101036 overexpression affected the levels of miR-21-3p and TMTC2, and endoplasmic reticulum (ER) stress in OSCC cells.

Results

The levels of hsa_circRNA_101036 and TMTC2 expression were significantly lower, while miR-21-3p expression was higher in tumor tissues and OSCC cells when compared to adjacent tissues and normal oral fibroblasts, respectively. The levels of HIF-1α and miR-21-3p expression were significantly increased under conditions of hypoxia, while the levels of hsa_circRNA_101036 and TMTC2 were decreased. The expression levels of proteins associated with ER stress, the proportions of apoptotic cells, and the levels of ROS were all increased by hypoxia stimulation. In addition, overexpression of hsa_circRNA_101036, but not mutant hsa_circRNA_101036, was found to enhance the effect of hypoxia on HSC3 and OECM-1 cells. Hsa_circRNA_101036 overexpression suppressed tumor growth and induced ER stress. Finally, knockdown of miR-21-3p had the same effect as overexpression of hsa_circRNA_101036.

Conclusion

Our findings suggest that hsa_circRNA_101036 plays a critical role in the development and progression of OSCC. Overexpression of hsa_circRNA_101036 aggravated ER stress, and increased cell apoptosis and ROS production in OSCC under hypoxic conditions. Hsa_circRNA_101036 up-regulated TMTC2 expression by sponging miR-21-3p in OSCC.

Keratinocytes Present Staphylococcus aureus Enterotoxins and Promote Malignant and Nonmalignant T Cell Proliferation in Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphoma is characterized by malignant T cells proliferating in a unique tumor microenvironment dominated by keratinocytes (KCs). Skin colonization and infection by Staphylococcus aureus are a common cause of morbidity and are suspected of fueling disease activity. In this study, we show that expression of HLA-DRs, high-affinity receptors for staphylococcal enterotoxins (SEs), by KCs correlates with IFN-γ expression in the tumor microenvironment. Importantly, IFN-γ induces HLA-DR, SE binding, and SE presentation by KCs to malignant T cells from patients with Sézary syndrome and malignant and nonmalignant T-cell lines derived from patients with Sézary syndrome and mycosis fungoides. Likewise, preincubation of KCs with supernatant from patient-derived SE-producing S aureus triggers proliferation in malignant T cells and cytokine release (including IL-2), when cultured with nonmalignant T cells. This is inhibited by pretreatment with engineered bacteriophage S aureus-specific endolysins. Furthermore, alteration in the HLA-DR-binding sites of SE type A and small interfering RNA-mediated knockdown of Jak3 and IL-2Rγ block induction of malignant T-cell proliferation. In conclusion, we show that upon exposure to patient-derived S aureus and SE, KCs stimulate IL-2Rγ/Jak3-dependent proliferation of malignant and nonmalignant T cells in an environment with nonmalignant T cells. These findings suggest that KCs in the tumor microenvironment play a key role in S aureus-mediated disease activity in cutaneous T-cell lymphoma.

The cross-talk between miRNAs and JAK/STAT pathway in cutaneous T cell lymphoma: Emphasis on therapeutic opportunities

Mycosis Fungoides (MF) and Sézary Syndrome (SS) belong to a wide spectrum of T cell lymphoproliferative disorders collectively termed cutaneous T cell lymphomas (CTCL). CTCLs represent an archetype of heterogeneous and dynamically variable lymphoproliferative neoplasms typified by distinct clinical, histological, immunophenotypic, and genetic features. Owing to its complex dynamics, the pathogenesis of CTCL remains elusive. However, in recent years, progress in CTCL classification combined with next-generation sequencing analyses has broadened the genetic and epigenetic spectrum of clearly defined CTCL entities such as MF and SS. Several large-scale genome studies have identified the polygenic nature of CTCL and unveiled an idiosyncratic mutational landscape involving genetic aberrations, epigenetic alterations, cell cycle dysregulation, apoptosis, and the constitutive activation of T cell/NF-κB/JAK-STAT signaling pathways. In this review, we summarize the evolving insights on how the intrinsic epigenetic events driven by dysregulated miRNAs, including the oncogenic and tumor-suppressive miRNAs, influence the pathogenesis of MF and SS. We also focus on the interplay between the JAK/STAT pathway and miRNAs in CTCL as well as the significance of the miRNA/STAT axis as a relevant pathogenetic mechanism underlying CTCL initiation and progression. Based on these biologic insights, the current status and recent progress on novel therapies with a strong biological rationale, including miRNA-targeted molecules and JAK/STAT-targeted therapy for CTCL management, are discussed.

Role of microRNAs in Immune Regulation with Translational and Clinical Applications

MicroRNAs (miRNAs) are 19-23 nucleotide long, evolutionarily conserved noncoding RNA molecules that regulate gene expression at the post-transcriptional level. In this review, involvement of miRNAs is summarized in the differentiation and function of immune cells, in anti-infective immune responses, immunodeficiencies and autoimmune diseases. Roles of miRNAs in anticancer immunity and in the transplantation of solid organs and hematopoietic stem cells are also discussed. Major focus is put on the translational clinical applications of miRNAs, including the establishment of noninvasive biomarkers for differential diagnosis and prediction of prognosis. Patient selection and response prediction to biological therapy is one of the most promising fields of application. Replacement or inhibition of miRNAs has enormous therapeutic potential, with constantly expanding possibilities. Although important challenges still await solutions, evaluation of miRNA fingerprints may contribute to an increasingly personalized management of immune dysregulation with a remarkable reduction in toxicity and treatment side effects. More detailed knowledge of the molecular effects of physical exercise and nutrition on the immune system may facilitate self-tailored lifestyle recommendations and advances in prevention.

CircDENND2D Inhibits PD-L1-Mediated Non-Small Cell Lung Cancer Metastasis and Immune Escape by Regulating miR-130b-3p/STK11 Axis

Local recurrence and distant metastasis of non-small cell lung cancer (NSCLC) caused by immune escape is one of the root causes of treatment difficulties. We aim to investigate the mechanism of immune escape in NSCLC. NSCLC tissues were collected. Cell proliferation was detected by CCK-8 assay. Cell migration and invasion ability was measured by Transwell assay. The expressions of E-cadherin, N-cadherin and PD-L1 were detected by Western blot. NSCLC cells were co-cultured with CD8+ T cells to simulate tumor microenvironment in vitro. The proportion of CD8+ T cells and apoptosis were detected by flow cytometry. Dual-luciferase reporter gene assay confirmed the targeting relationship of circDENND2D and STK11. The expressions of circDENND2D and STK1 were down-regulated, while miR-130b-3p expression was up-regulated in NSCLC tissues. Overexpression of circDENND2D or STK11 inhibited NSCLC cells proliferation, migration and invasion, and attenuated the immune escape of NSCLC cells. CircDENND2D targeted miR-130b-3p to competitively promote STK11 expression. STK11 knockdown or miR-130b-3p overexpression attenuated the function of circDENND2D overexpression on NSCLC cells. CircDENND2D inhibited metastasis and immune escape of NSCLC by regulating miR-130b-3p/STK11 axis.

Emerging drugs for the treatment of cutaneous T-cell lymphoma

INTRODUCTION

Cutaneous T cell lymphoma (CTCL) is a rare and incurable group of non-Hodgkin lymphomas that manifests as patches, plaques, tumors, and/or erythroderma in the skin. Standard skin-directed therapies for CTCL are effective in patients with indolent early-stage disease but more advanced/refractory stage patients require systemic therapies. However, none of the treatments are considered curative and most patients suffer from relapses. Biologic therapies and immunotherapy provide novel treatment options for patients with advanced or refractory disease.

AREAS COVERED

This review provides a discussion of recently approved biological and novel therapeutics that are actively developed for the management of the heterogenous group of CTCL.

EXPERT OPINION

Mogamulizumab and brentuximab vedotin have reached the market and are approved for the treatment of CTCL, providing valuable options. Additionally, therapies utilizing immune checkpoint inhibitors, miRNA inhibitors, and peptide inhibitors show promising results in clinical trials. Durvalumab, pembrolizumab, TTI-621, BNZ-1, and MRG-106 are several of the emerging treatments still in trials. Further combinatorial studies are needed as none of the treatments have demonstrated long term remissions.

Exosomes produced by melanoma cells significantly influence the biological properties of normal and cancer-associated fibroblasts

The incidence of cutaneous malignant melanoma is increasing worldwide. While the treatment of initial stages of the disease is simple, the advanced disease frequently remains fatal despite novel therapeutic options . This requires identification of novel therapeutic targets in melanoma. Similarly to other types of tumours, the cancer microenvironment plays a prominent role and determines the biological properties of melanoma. Importantly, melanoma cell-produced exosomes represent an important tool of intercellular communication within this cancer ecosystem. We have focused on potential differences in the activity of exosomes produced by melanoma cells towards melanoma-associated fibroblasts and normal dermal fibroblasts. Cancer-associated fibroblasts were activated by the melanoma cell-produced exosomes significantly more than their normal counterparts, as assessed by increased transcription of genes for inflammation-supporting cytokines and chemokines, namely IL-6 or IL-8. We have observed that the response is dependent on the duration of the stimulus via exosomes and also on the quantity of exosomes. Our study demonstrates that melanoma-produced exosomes significantly stimulate the tumour-promoting proinflammatory activity of cancer-associated fibroblasts. This may represent a potential new target of oncologic therapy .

Identification of a Distinct miRNA Regulatory Network in the Tumor Microenvironment of Transformed Mycosis Fungoides

Simple Summary

Transformed mycosis fungoides (LCT-MF) is a histopathological marker of poor prognosis and associated with worse survival. We compared miRNA and mRNA expression profiles of LCT-MF with classic MF and found a distinct miRNA regulatory network modulated immunosuppressive tumor microenvironment in LCT-MF. Our findings provide novel insights and therapeutic targets for LCT-MF.

Abstract

Large cell transformation of mycosis fungoides (LCT-MF) occurs in 20–50% of advanced MF and is generally associated with poor response and dismal prognosis. Although different mechanisms have been proposed to explain the pathogenesis, little is known about the role of microRNAs (miRs) in transcriptional regulation of LCT-MF. Here, we investigated the miR and mRNA expression profile in lesional skin samples of patients with LCT-MF and non-LCT MF using RNA-seq analysis. We found miR-146a and miR-21 to be significantly upregulated, and miR-708 the most significantly downregulated miR in LCT-MF. Integration of miR and mRNA expression profiles revealed the miR-regulated networks in LCT-MF. Ingenuity pathway analysis (IPA) demonstrated the involvement of genes for ICOS-ICOSL, PD1-PDL1, NF-κB, E2F transcription, and molecular mechanisms of cancer signaling pathways. Quantitative real time (qRT)-PCR results of target genes were consistent with the RNA-seq data. We further identified the immunosuppressive tumor microenvironment (TME) in LCT-MF. Moreover, our data indicated that miR-146a, -21 and -708 are associated with the immunosuppressive TME in LCT-MF. Collectively, our results suggest that the key LCT-MF associated miRs and their regulated networks may provide insights into its pathogenesis and identify promising targets for novel therapeutic strategies.