Histone deacetylase inhibitors inhibit metastasis by restoring a tumor suppressive microRNA-150 in advanced cutaneous T-cell lymphoma

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.

Comprehensive analysis of microRNAs modulated by histone deacetylase inhibitors identifies microRNA-7-5p with anti-myeloma effect

Basic research to expand treatment options for multiple myeloma is greatly needed due to the refractory nature of the disease. Histone deacetylase (HDAC) inhibitors, which are epigenetic regulators, are attractive but have limited applications. MicroRNAs (miRNAs), which are also epigenetic regulators, are important molecules that may lead to future therapeutic breakthroughs. In this study, we comprehensively searched for miRNAs that are altered by HDAC inhibitors in myeloma cells. We identified miR-7-5p (miR-7) as a miRNA downregulated by HDAC inhibitors. Transfection of myeloma cell lines with miR-7 suppressed cell proliferation, induced apoptosis, and enhanced the effects of the HDAC inhibitor panobinostat. Expression of miR-7 was downregulated by c-Myc inhibition, but upregulated by bortezomib. Comprehensive examination of miR-7 targets revealed four candidates: SLC6A9, LRRC59, EXOSC2, and PSME3. Among these, we focused on PSME3, an oncogene involved in proteasome capacity in myeloma cells. PSME3 knockdown increases myeloma cell death and panobinostat sensitivity. In conclusion, miR-7, which is downregulated by HDAC inhibitors, is a tumor suppressor that targets PSME3. This miR-7 downregulation may be involved in HDAC inhibitor resistance. In addition, combinations of anti-myeloma drugs that complement changes in miRNA expression should be considered.

"Next top" mouse models advancing CTCL research

This review systematically describes the application of in vivo mouse models in studying cutaneous T-cell lymphoma (CTCL), a complex hematological neoplasm. It highlights the diverse research approaches essential for understanding CTCL's intricate pathogenesis and evaluating potential treatments. The review categorizes various mouse models, including xenograft, syngeneic transplantation, and genetically engineered mouse models (GEMMs), emphasizing their contributions to understanding tumor-host interactions, gene functions, and studies on drug efficacy in CTCL. It acknowledges the limitations of these models, particularly in fully replicating human immune responses and early stages of CTCL. The review also highlights novel developments focusing on the potential of skin-targeted GEMMs in studying natural skin lymphoma progression and interactions with the immune system from onset. In conclusion, a balanced understanding of these models' strengths and weaknesses are essential for accelerating the deciphering of CTCL pathogenesis and developing treatment methods. The GEMMs engineered to target specifically skin-homing CD4+ T cells can be the next top mouse models that pave the way for exploring the effects of CTCL-related genes.

What Is New in Cutaneous T Cell Lymphoma?

PURPOSE OF REVIEW

This review focuses on updates in prognosis, pathogenesis, and treatment of cutaneous T cell lymphoma (CTCL).

RECENT FINDINGS

Cohort studies indicate imaging may be necessary in early-stage CTCL. Risk factors for progression of CTCL have been identified. Interactions between malignant cells and the tumor microenvironment (TME) and the skin microbiome advance the understanding of pathogenesis and tumor cell dissemination. Studies support a hypothesis of circulating malignant tumor cells. MicroRNA (miR) influence tumor progression and prognosis; the IL22-STAT3-CCL20 cascade may be a novel target. IL-4, IL-5, and IL-31 cytokines are relevant for pruritus and could be targets for therapeutic interventions. Systemic therapies, such as JAK inhibitors, targeted antibodies, and checkpoint inhibitors, show promise in advanced stages. Allogenic hematopoietic stem cell transplantation provides a potential curative option for patients. Further investigations of prognosis and translational research are necessary to improve stratification of patients for treatment.

Suberoylanilide hydroxamic acid (SAHA) attenuates memory impairment in the offspring of rats exposed to sevoflurane anesthesia

BACKGROUND

SAHA was reported to enhance the expression of miR-129-5p, which was predicted to bind to 3' UTR of CASP-6, a gene playing crucial roles in the pathogenesis of memory impairment. Whether SAHA/miR-129-5p/CASP-6 is involved in the pathogenesis of prenatal exposure to sevoflurane remains to be explored.

METHODS

Morris water maze test was performed to evaluate the functional parameters of learning and memory. Quantitative real-time qPCR was carried out to analyze the expression of miRNAs and CASP-6 mRNA under different conditions.

RESULTS

Sevoflurane exposure of pregnant rats and SAHA treatment of the offspring had no effect on the blood gases, litter size, survival rate and weight. SAHA administration remarkably reversed the learning and memory impairment in prenatal rats caused by sevoflurane exposure. Mechanistically, the abnormal expression of miR-129-5p and CASP-6 in the offspring of pregnant rats exposed to sevoflurane was effectively restored by SAHA treatment. The luciferase activity of CASP-6 vector was effectively inhibited by miR-129-5p in primary neuron cells of rats. Moreover, the expression of CASP-6 mRNA and protein was significantly suppressed by miR-129-5p and SAHA treatment in a dose-dependent manner.

CONCLUSION

Our work demonstrated that the administration of SAHA suppressed the expression of CASP-6 via modulating the expression of miR-129-5p, and SAHA may rescue the apoptosis of neurons caused by exposure to sevoflurane. The underlying mechanism might be the ability of SAHA to relieve learning and memory impairment in the offspring of the pregnant rats exposed to sevoflurane.

Restoration of WT1/miR-769-5p axis by HDAC1 inhibition promotes MMT reversal in mesenchymal-like mesothelial cells

Histone acetylation/deacetylation play an essential role in modifying chromatin structure and in regulating cell plasticity in eukaryotic cells. Therefore, histone deacetylase (HDAC) pharmacological inhibitors are promising tools in the therapy of fibrotic diseases and in cancer. Peritoneal fibrosis is a pathological process characterized by many cellular and molecular alterations, including the acquisition of invasive/pro-fibrotic abilities by mesothelial cells (MCs) through induction of mesothelial to mesenchymal transition (MMT). The aim of this study was to characterize the molecular mechanism of the antifibrotic role of HDAC1 inhibition. Specifically, treatment with MS-275, an HDAC1-3 inhibitor previously known to promote MMT reversal, induced the expression of several TGFBRI mRNA-targeting miRNAs. Among them, miR-769-5p ectopic expression was sufficient to promote MMT reversal and to limit MC migration and invasion, whereas miR-769-5p silencing further enhanced mesenchymal gene expression. These results were confirmed by HDAC1 genetic silencing. Interestingly, miR-769-5p silencing maintained mesenchymal features despite HDAC1 inhibition, thus indicating that it is necessary to drive MMT reversal induced by HDAC1 inhibition. Besides TGFBRI, miR-769-5p was demonstrated to target SMAD2/3 and PAI-1 expression directly. When analyzing molecular mechanisms underlying miR-769-5p expression, we found that the transcription factor Wilms' tumor 1 (WT1), a master gene controlling MC development, binds to the miR-769-5p promoter favoring its expression. Interestingly, both WT1 expression and binding to miR-769-5p promoter were increased by HDAC1 inhibition and attenuated by TGFβ1 treatment. Finally, we explored the significance of these observations in the cell-to-cell communication: we evaluated the ability of miR-769-5p to be loaded into extracellular vesicles (EVs) and to promote MMT reversal in recipient mesenchymal-like MCs. Treatment of fibrotic MCs with EVs isolated from miR-769-5p over-expressing MCs promoted the down-regulation of specific mesenchymal targets and the reacquisition of an epithelial-like morphology. In conclusion, we highlighted an HDAC1-WT1-miR-769-5p axis potentially relevant for therapies aimed at counteracting organ fibrosis.

MiR-150 in HTLV-1-infection and T-cell transformation

Human T-cell leukemia virus-1 (HTLV-1) is a retrovirus that persistently infects CD4+ T-cells, and is the causative agent of adult T-cell leukemia/lymphoma (ATLL), tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM) and several inflammatory diseases. T-cell transformation by HTLV-1 is driven by multiple interactions between viral regulatory proteins and host cell pathways that govern cell proliferation and survival. Studies performed over the last decade have revealed alterations in the expression of many microRNAs in HTLV-1-infected cells and ATLL cells, and have identified several microRNA targets with roles in the viral life cycle and host cell turnover. This review centers on miR-150-5p, a microRNA whose expression is temporally regulated during lymphocyte development and altered in several hematological malignancies. The levels of miR-150-5p are reduced in many HTLV-1-transformed- and ATLL-derived cell lines. Experiments in these cell lines showed that downregulation of miR-150-5p results in activation of the transcription factor STAT1, which is a direct target of the miRNA. However, data on miR-150-5p levels in freshly isolated ATLL samples are suggestive of its upregulation compared to controls. These apparently puzzling findings highlight the need for more in-depth studies of the role of miR-150-5p in HTLV-1 infection and pathogenesis based on knowledge of miR-150-5p-target mRNA interactions and mechanisms regulating its function in normal leukocytes and hematologic neoplasms.

MicroRNAs and their signaling pathway in mycosis fungoides

BACKGROUND

Oncogenic microRNAs, a kind of stable epigenetic inhibitors, often deregulated in Mycosis fungoides (MF) which affect the skin and tend to transform and spread.

RESULTS

Previous studies investigating the de-expression of microRNA in MF patients skin biopsies identified that they were not only regulated by signaling pathway, but also regulated other signaling pathway. Furthermore, studies have elucidated the molecular mechanisms of the STAT signaling pathway that can promote a great diversity of miRNA expression via cytokine binding receptors, activating Janus kinase-3 and STAT proteins. But some non-STAT signaling pathway with mircoRNA de-expression in MF was incomplete.

CONCLUSION

Taken together, these studies demonstrate that microRNA may be used as the prognosis, progression and diagnose of MF, as they can not only control MF cell proliferation, but also induce MF cell apoptosis.

Implication of microRNAs in Carcinogenesis with Emphasis on Hematological Malignancies and Clinical Translation

MicroRNAs (miRNAs) are evolutionarily conserved small non-coding RNAs, that are involved in the multistep process of carcinogenesis, contributing to all established hallmarks of cancer. In this review, implications of miRNAs in hematological malignancies and their clinical utilization fields are discussed. As components of the complex regulatory network of gene expression, influenced by the tissue microenvironment and epigenetic modifiers, miRNAs are “micromanagers” of all physiological processes including the regulation of hematopoiesis and metabolic pathways. Dysregulated miRNA expression levels contribute to both the initiation and progression of acute leukemias, the metabolic reprogramming of malignantly transformed hematopoietic precursors, and to the development of chemoresistance. Since they are highly stable and can be easily quantified in body fluids and tissue specimens, miRNAs are promising biomarkers for the early detection of hematological malignancies. Besides novel opportunities for differential diagnosis, miRNAs can contribute to advanced chemoresistance prediction and prognostic stratification of acute leukemias. Synthetic oligonucleotides and delivery vehicles aim the therapeutic modulation of miRNA expression levels. However, major challenges such as efficient delivery to specific locations, differences of miRNA expression patterns between pediatric and adult hematological malignancies, and potential side effects of miRNA-based therapies should be considered.

Downregulation of miR-26 promotes invasion and metastasis via targeting interleukin-22 in cutaneous T-cell lymphoma

It has been reported that certain microRNAs (miRNA) are associated with the pathogenesis of lymphoma. We have previously demonstrated that histone deacetylase inhibitors restore tumor-suppressive miRNAs, such as miR-16, miR-29, miR-150, and miR-26, in advanced cutaneous T-cell lymphoma (CTCL). Among these, the function of miR-26 remains unclear. In this study, we aimed to reveal the function of miR-26 in CTCL oncogenesis. First, we confirmed that the miR-26 family was markedly dysregulated in CTCL cell lines and primary samples. In vivo analysis using miR-26a-transduced CTCL cells injected into immunodeficient NOG mice demonstrated the significant prolonged survival of the mice, suggesting that the miRNA had a tumor-suppressive function. We performed gene expression assays and identified 12 candidate miR-26 targets, namely RGS13, FAM71F1, OAF, SNX21, CDH2, PTPLB, IL22, DNAJB5, CASZ1, CACNA1C, MYH10, and CNR1. Among these, IL22 was the most likely candidate target because the IL-22-STAT3-CCL20-CCR6 cascade is associated with tumor invasion and metastasis of advanced CTCL. In vitro analysis of IL22 and IL22RA knockdown and miR-26 transduction demonstrated inhibited CTCL cell migration. In particular, IL22 knockdown induced cell apoptosis. Finally, we conducted in vivo inoculation analysis of mice injected with shIL22-transfected CTCL cells, and found no tumor invasion or metastasis in the inoculated mice, although the control mice showed multiple tumor invasions and metastases. These results, along with our previous data, demonstrated that miR-26 is a tumor suppressor that is associated with tumor invasion and the metastasis of advanced CTCL by regulating the IL-22-STAT3-CCL20 cascade. Therefore, a IL-22-targeting therapy could be a novel therapeutic strategy for advanced CTCL.

Mogamulizumab induces long term immune restoration and reshapes tumor heterogeneity in Sézary syndrome

BACKGROUND

Mogamulizumab, an anti-CCR4 monoclonal antibody, has been shown to increase progression-free survival in cutaneous T-cell lymphoma.

OBJECTIVES

We hypothesized that besides the targeted depletion of Sézary cells (SCs), mogamulizumab may reshape the immune tumor microenvironment.

METHODS

Both malignant and benign compartments from 26 Sézary patients with B2 stage before mogamulizumab initiation were prospectively analyzed using KIR3DL2 and TCR-Vβ markers, serological markers and molecular assessments of clonality.

RESULTS

Prior to mogamulizumab, the benign subset of CD4+ T-cells displayed exhausted phenotypes, with an increased gradient in PD1/TIGIT/DNAM/CD27/CD28 and CD70 expression from age- matched controls to patient benign CD4+T cells and to SCs. All patients presented SCs with heterogeneous phenotypes and differential expression of individual markers were found within distinct malignant subsets. Early complete blood response was observed in 17/26 patients and was associated to a higher baseline CCR4 expression. A drastic decrease in benign T cells and activated Treg counts was observed during the first 4 weeks. Long-term follow-up revealed the emergence of an immune restoration involving CD8+, naive and stem-memory CD4+T cells, with almost complete disappearance of exhausted lymphocytes. Development of resistance/tumor escape to mogamulizumab was associated to the emergence of CCR4- SCs in blood and skin, displaying significant changes in their heterogeneity patterns, and not univocally explained by mutations within CCR4 coding regions.

CONCLUSIONS

Mogamulizumab is likely contributing to the restoration of an efficient immunity and reshapes not only the malignant lymphocyte subset but also the benign subset. These results have potential implications for optimal therapeutic sequences and/or combinations.

Challenging Cutaneous T-Cell Lymphoma: What Animal Models Tell us So Far

Cutaneous T-cell lymphomas are characterized by heterogeneity of clinical variants, further complicated by genomic and microenvironmental variables. Furthermore, in vitro experiments are hampered by the low culture efficiency of these malignant cells. Animal models are essential for understanding the pathogenetic mechanisms underlying malignancy and for discovering new anticancer treatments. They are divided into two main categories: those in which tumors arise in the host owing to genetic modifications and those that use tumor cell transplantation. In this review, we summarize the attempts to decipher the complexity of the pathogenesis of cutaneous T-cell lymphoma by exploiting genetically modified and xenograft models.

MicroRNA-325 inhibits the proliferation and induces the apoptosis of T cell acute lymphoblastic leukemia cells in a BAG2-dependent manner

The inhibitory effect of microRNA (miR)-325 in multiple different types of cancer cell has been identified; however, its biological function in T cell acute lymphoblastic leukemia (T-ALL) remains unknown. Moreover, Bcl-2-associated athanogene (BAG)2 is highly expressed in a various types of tumors and is regarded as an anti-apoptotic gene. In the present study, the roles of miR-325 and BAG2 in a T-ALL cell line (Jurkat cells) were investigated. BAG2 and miR-325 expression levels in clinical blood samples from healthy donors and pediatric patients with T-ALL, as well as in T-ALL cell lines was detected using western blot analysis and/or reverse transcription-quantitative PCR. Dual-luciferase reporter gene assays and TargetScan were used to evaluate the interaction between BAG2 and miR-325. Small interfering RNA technology was applied to knockdown BAG2 expression in Jurkat cells. The effects of miR-325 mimic and BAG2 downregulation on the proliferation and apoptosis were assessed by an MTT assay, flow cytometry and western blot analysis. The results revealed that the expression of miR-325 was downregulated in blood samples from pediatric patients and in T-ALL cell lines, and its expression was lowest in Jurkat cells. The expression levels of BAG2 exhibited the opposite results. The knockdown of BAG2 markedly induced the apoptosis and inhibited the proliferation of Jurkat cells. In addition, the overexpression of miR-325 significantly inhibited the growth and promoted the apoptosis of Jurkat cells, with these effects being eliminated by BAG2 overexpression. In conclusion, the findings of the present study demonstrated that miR-325 directly targets the BAG2 gene and that the introduction of miR-325 can accelerate apoptosis and suppress the proliferation of Jurkat cells by silencing BAG2 expression.

Epigenetics of cutaneous T-cell lymphoma: biomarkers and therapeutic potentials

Cutaneous T-cell lymphomas (CTCLs) are a heterogeneous group of skin-homing non-Hodgkin lymphomas. There are limited options for effective treatment of patients with advanced-stage CTCL, leading to a poor survival rate. Epigenetics plays a pivotal role in regulating gene expression without altering the DNA sequence. Epigenetic alterations are involved in virtually all key cancer-associated pathways and are fundamental to the genesis of cancer. In recent years, the epigenetic hallmarks of CTCL have been gradually elucidated and their potential values in the diagnosis, prognosis, and therapeutic intervention have been clarified. In this review, we summarize the current knowledge of the best-studied epigenetic modifications in CTCL, including DNA methylation, histone modifications, microRNAs, and chromatin remodelers. These epigenetic regulators are essential in the development of CTCL and provide new insights into the clinical treatments of this refractory disease.

Non-Coding RNAs as Mediators of Epigenetic Changes in Malignancies

Non-coding RNAs (ncRNAs) are untranslated RNA molecules that regulate gene expressions. NcRNAs include small nuclear RNAs (snRNAs), small nucleolar RNAs (snoRNAs), ribosomal RNAs (rRNAs), transfer RNAs (tRNAs), circular RNAs (cRNAs) and piwi-interacting RNAs (piRNAs). This review focuses on two types of ncRNAs: microRNAs (miRNAs) or short interfering RNAs (siRNAs) and long non-coding RNAs (lncRNAs). We highlight the mechanisms by which miRNAs and lncRNAs impact the epigenome in the context of cancer. Both miRNAs and lncRNAs have the ability to interact with numerous epigenetic modifiers and transcription factors to influence gene expression. The aberrant expression of these ncRNAs is associated with the development and progression of tumors. The primary reason for their deregulated expression can be attributed to epigenetic alterations. Epigenetic alterations can cause the misregulation of ncRNAs. The experimental evidence indicated that most abnormally expressed ncRNAs impact cellular proliferation and apoptotic pathways, and such changes are cancer-dependent. In vitro and in vivo experiments show that, depending on the cancer type, either the upregulation or downregulation of ncRNAs can prevent the proliferation and progression of cancer. Therefore, a better understanding on how ncRNAs impact tumorigenesis could serve to develop new therapeutic treatments. Here, we review the involvement of ncRNAs in cancer epigenetics and highlight their use in clinical therapy.

Suppressed microRNA-195-5p expression in mycosis fungoides promotes tumor cell proliferation

BACKGROUND

Several cancers, including mycosis fungoides (MF), have reported dysregulation of miR-195-5p. miR-195-5p plays a role in cell cycle regulation in several malignant diseases.

OBJECTIVES

This study aimed to investigate: (a) the expression level of miR-195-5p in lesional MF skin biopsies and (b) the potential regulatory roles of miR-195-5p in MF.

METHODS

Quantitative real-time polymerase chain reaction (RT-qPCR) was used to determine miR-195-5p expression in MF skin biopsies and cell lines. The effect of miR-195-5p and ADP-ribosylation factor-like protein 2 (ARL2) on cell cycle and apoptosis was measured by flow cytometry assays. Changes in ARL2 expression were determined by RT-qPCR and Western blotting (WB).

RESULTS

We found lower expression levels of miR-195-5p in lesional skin from MF patients compared with non-lesional MF skin and skin from healthy volunteers. Additionally, miR-195-5p showed lower expression levels in the skin from patients with disease progression compared with patients with stable disease. In vitro studies showed that overexpression of miR-195-5p induced a cell cycle arrest in G0G1. Using microarray analysis, we identified several genes that were regulated after miR-195-5p overexpression. The most downregulated gene after miR-195-5p mimic transfection was ARL2. RT-qPCR and WB analyses confirmed downregulation of ARL2 following transfection with miR-195-5p mimic. Lastly, transfection with siRNA against ARL2 also induced a G0G1 arrest.

CONCLUSION

Upregulation of miR-195-5p in MF inhibits cycle arrest by downregulation of ARL2. miR-195-5p may thus function as a tumor suppressor in MF and low miR-195-5p expression in lesional MF skin may promote disease progression.

MicroRNAs in the Pathogenesis, Diagnosis, Prognosis and Targeted Treatment of Cutaneous T-Cell Lymphomas

Cutaneous T-cell lymphoma (CTCL) represents a heterogeneous group of potentially devastating primary skin malignancies. Despite decades of intense research efforts, the pathogenesis is still not fully understood. In the early stages, both clinical and histopathological diagnosis is often difficult due to the ability of CTCL to masquerade as benign skin inflammatory dermatoses. Due to a lack of reliable biomarkers, it is also difficult to predict which patients will respond to therapy or progress towards severe recalcitrant disease. In this review, we discuss recent discoveries concerning dysregulated microRNA (miR) expression and putative pathological roles of oncogenic and tumor suppressive miRs in CTCL. We also focus on the interplay between miRs, histone deacetylase inhibitors, and oncogenic signaling pathways in malignant T cells as well as the impact of miRs in shaping the inflammatory tumor microenvironment. We highlight the potential use of miRs as diagnostic and prognostic markers, as well as their potential as therapeutic targets. Finally, we propose that the combined use of miR-modulating compounds with epigenetic drugs may provide a novel avenue for boosting the clinical efficacy of existing anti-cancer therapies in CTCL.

Analysis of Dual Class I Histone Deacetylase and Lysine Demethylase Inhibitor Domatinostat (4SC-202) on Growth and Cellular and Genomic Landscape of Atypical Teratoid/Rhabdoid

Central nervous system atypical teratoid/rhabdoid tumors (ATRTs) are rare and aggressive tumors with a very poor prognosis. Current treatments for ATRT include resection of the tumor, followed by systemic chemotherapy and radiation therapy, which have toxic side effects for young children. Gene expression analyses of human ATRTs and normal brain samples indicate that ATRTs have aberrant expression of epigenetic markers including class I histone deacetylases (HDAC’s) and lysine demethylase (LSD1). Here, we investigate the effect of a small molecule epigenetic modulator known as Domatinostat (4SC-202), which inhibits both class I HDAC’s and Lysine Demethylase (LSD1), on ATRT cell survival and single cell heterogeneity. Our findings suggest that 4SC-202 is both cytotoxic and cytostatic to ATRT in 2D and 3D scaffold cell culture models and may target cancer stem cells. Single-cell RNA sequencing data from ATRT-06 spheroids treated with 4SC-202 have a reduced population of cells overexpressing stem cell-related genes, including SOX2. Flow cytometry and immunofluorescence on 3D ATRT-06 scaffold models support these results suggesting that 4SC-202 reduces expression of cancer stem cell markers SOX2, CD133, and FOXM1. Drug-induced changes to the systems biology landscape are also explored by multi-omics enrichment analyses. In summary, our data indicate that 4SC-202 has both cytotoxic and cytostatic effects on ATRT, targets specific cell sub-populations, including those with cancer stem-like features, and is an important potential cancer therapeutic to be investigated in vivo.

Animal Models in Microbeam Radiation Therapy: A Scoping Review

BACKGROUND

Microbeam Radiation Therapy (MRT) is an innovative approach in radiation oncology where a collimator subdivides the homogeneous radiation field into an array of co-planar, high-dose beams which are tens of micrometres wide and separated by a few hundred micrometres.

OBJECTIVE

This scoping review was conducted to map the available evidence and provide a comprehensive overview of the similarities, differences, and outcomes of all experiments that have employed animal models in MRT.

METHODS

We considered articles that employed animal models for the purpose of studying the effects of MRT. We searched in seven databases for published and unpublished literature. Two independent reviewers screened citations for inclusion. Data extraction was done by three reviewers.

RESULTS

After screening 5688 citations and 159 full-text papers, 95 articles were included, of which 72 were experimental articles. Here we present the animal models and pre-clinical radiation parameters employed in the existing MRT literature according to their use in cancer treatment, non-neoplastic diseases, or normal tissue studies.

CONCLUSIONS

The study of MRT is concentrated in brain-related diseases performed mostly in rat models. An appropriate comparison between MRT and conventional radiotherapy (instead of synchrotron broad beam) is needed. Recommendations are provided for future studies involving MRT.

Novel cell adhesion/migration pathways are predictive markers of HDAC inhibitor resistance in cutaneous T cell lymphoma

Background

Treatment for Cutaneous T Cell Lymphoma (CTCL) is generally not curative. Therefore, selecting therapy that is effective and tolerable is critical to clinical decision-making. Histone deacetylase inhibitors (HDACi), epigenetic modifier drugs, are commonly used but effective in only ~30% of patients. There are no predictive markers of HDACi response and the CTCL histone acetylation landscape remains unmapped. We sought to identify pre-treatment molecular markers of resistance in CTCL that progressed on HDACi therapy.

Methods

Purified T cells from 39 pre/post-treatment peripheral blood samples and skin biopsies from 20 patients were subjected to RNA-seq and ChIP-seq for histone acetylation marks (H3K14/9 ac, H3K27ac). We correlated significant differences in histone acetylation with gene expression in HDACi-resistant/sensitive CTCL. We extended these findings in additional CTCL patient cohorts (RNA-seq, microarray) and using ELISA in matched CTCL patient plasma.

Findings

Resistant CTCL exhibited high levels of histone acetylation, which correlated with increased expression of 338 genes (FDR < 0·05), including some novel to CTCL: BIRC5 (anti-apoptotic); RRM2 (cell cycle); TXNDC5, GSTM1 (redox); and CXCR4, LAIR2 (cell adhesion/migration). Several of these, including LAIR2, were elevated pre-treatment in HDACi-resistant CTCL. In CTCL patient plasma (n = 6), LAIR2 protein was also elevated (p < 0·01) compared to controls.

Interpretation

This study is the first to connect genome-wide differences in chromatin acetylation and gene expression to HDACi-resistance in primary CTCL. Our results identify novel markers with high pre-treatment expression, such as LAIR2, as potential prognostic and/or predictors of HDACi-resistance in CTCL.

Funding

NIH:CA156690, CA188286; NCATS: WU-ICTS UL1 TR000448; Siteman Cancer Center: CA091842.

Angiogenesis in cutaneous T-cell lymphoma - proteomic approaches

Neoangiogenesis plays an important role in cutaneous lymphoma pathogenesis. Cutaneous T-cell lymphoma (CTCL) is characterized by the presence of malignant T-cell clones in the skin. Vascular microenvironment of lymphomas accelerates neoangiogenesis through several factors released by tumoral cells: VEGF family, bFGF and PIGF. Tumor stroma (fibroblasts, inflammatory and immune cells) also plays a crucial role, by providing additional angiogenic factors. The angiogenic process through the VEGF-VEGFR axis can promote survival, proliferation and metastasis via autocrine mechanisms in cutaneous lymphomas. Microvascular density (MVD) measures the neo-vascularization of cutaneous lymphoma, generated by the response of tumor cells, proangiogenic stromal cells, and benign T/B lymphocytes within the tumor inflammatory infiltrate. Pro-angiogenic proteins have been found to indicate the evolution and prognosis in patients with CTCL. In conclusion, anti-angiogenic therapeutic protocols can target tumor vasculature or malignant tumor cells directly or through a large number of combinations with other drugs. The integration of proteomics into clinical practice based on high-throughput technologies leads to the development of personalized medicine, adapting the specific biomarkers to the application of cancer-type specific individual drug targets.

Mechanism of Action for HDAC Inhibitors-Insights from Omics Approaches

Histone deacetylase inhibitors (HDIs) are a class of prominent epigenetic drugs that are currently being tested in hundreds of clinical trials against a variety of diseases. A few compounds have already been approved for treating lymphoma or myeloma. HDIs bind to the zinc-containing catalytic domain of the histone deacetylase (HDACs) and they repress the deacetylase enzymatic activity. The broad therapeutic effect of HDIs with seemingly low toxicity is somewhat puzzling when considering that most HDIs lack strict specificity toward any individual HDAC and, even if they do, each individual HDAC has diverse functions under different physiology scenarios. Here, we review recent mechanistic studies using omics approaches, including epigenomics, transcriptomics, proteomics, metabolomics, and chemoproteomics, methods. These omics studies provide non-biased insights into the mechanism of action for HDIs.

Histone Deacetylases (HDACs) Guided Novel Therapies for T-cell lymphomas

T-cell lymphomas are a heterogeneous group of cancers with different pathogenesis and poor prognosis. Histone deacetylases (HDACs) are epigenetic modifiers that modulate many key biological processes. In recent years, HDACs have been fully investigated for their roles and potential as drug targets in T-cell lymphomas. In this review, we have deciphered the modes of action of HDACs, HDAC inhibitors as single agents, and HDACs guided combination therapies in T-cell lymphomas. The overview of HDACs on the stage of T-cell lymphomas, and HDACs guided therapies both as single agents and combination regimens endow great opportunities for the cure of T-cell lymphomas.

miRNA‑135a regulates Hut78 cell proliferation via the GATA‑3/TOX signaling pathway

The present study investigated the role of microRNA‑135a (miR‑135a) in cutaneous T‑cell lymphoma (CTCL) proliferation. Compared with the normal T lymphocyte control cell line, the mRNA and protein levels of GATA binding protein 3 (GATA‑3) were markedly increased in the Hut78 cell line and miR‑135a was markedly decreased (P<0.05). Based on bioinformatics, the target gene of miR‑135a was identified as GATA‑3. Dual luciferase and pre‑miR‑135a assays showed that miR‑135a regulated the translation of GATA‑3. In addition, the overexpression of miR‑135a mimics decreased the protein levels of GATA‑3 and thymocyte selection‑associated high mobility group box (TOX). The substantially increased mRNA and protein levels of GATA‑3 may be associated with the downregulation of miR‑135a, leading to T‑cell deregulation and proliferation through GATA‑3/TOX regulation and subsequently causing CTCL.

Histone deacetylase 6 in cancer

Histone acetylation and deacetylation are important epigenetic mechanisms that regulate gene expression and transcription. Histone deacetylase 6 (HDAC6) is a unique member of the HDAC family that not only participates in histone acetylation and deacetylation but also targets several nonhistone substrates, such as α-tubulin, cortactin, and heat shock protein 90 (HSP90), to regulate cell proliferation, metastasis, invasion, and mitosis in tumors. Furthermore, HDAC6 also upregulates several critical factors in the immune system, such as program death receptor-1 (PD-1) and program death receptor ligand-1 (PD-L1) receptor, which are the main targets for cancer immunotherapy. Several selective HDAC6 inhibitors are currently in clinical trials for cancer treatment and bring hope for patients with malignant tumors. A fuller understanding of HDAC6 as a critical regulator of many cellular pathways will help further the development of targeted anti-HDAC6 therapies. Here, we review the unique features of HDAC6 and its role in cancer, which make HDAC6 an appealing drug target.

Epigenetic regulation of miR-200 as the potential strategy for the therapy against triple-negative breast cancer

MicroRNAs (miRNAs) are a class of small, non-coding RNAs that are involved in the regulation of gene expression at the post-transcriptional level. MicroRNAs play an important role in cancer cell proliferation, survival and apoptosis. Epigenetic modifiers regulate the microRNA expression. Among the epigenetic players, histone deacetylases (HDACs) function as the key regulators of microRNA expression. Epigenetic machineries such as DNA and histone modifying enzymes and various microRNAs have been identified as the important contributors in cancer initiation and progression. Recent studies have shown that developing innovative microRNA-targeting therapies might improve the human health, specifically against the disease areas of high unmet medical need. Thus microRNA based therapeutics are gaining importance for anti-cancer therapy. Studies on Triple negative breast cancer (TNBC) have revealed the early relapse and poor overall survival of patients which needs immediate therapeutic attention. In this report, we focus the effect of HDAC inhibitors on TNBC cell proliferation, regulation of microRNA gene expression by a series of HDAC genes, chromatin epigenetics, epigenetic remodelling at miR-200 promoter and its modulation by various HDACs. We also discuss the need for identifying novel HDAC inhibitors for modulation of miR-200 in triple negative breast cancer.

Histone deacetylase inhibitors downregulate CCR4 expression and decrease mogamulizumab efficacy in CCR4-positive mature T-cell lymphomas

Histone deacetylase inhibitors are promising agents for various T-cell lymphomas, including cutaneous T-cell lymphoma, peripheral T-cell lymphoma, and adult T-cell lymphoma/leukemia. CCR4 is an important therapeutic target molecule because mogamulizumab, an anti-CCR4 antibody, has shown promising efficacy against various T-cell lymphomas. In this study, we examined the in vitro synergistic effects of mogamulizumab and histone deacetylase inhibitors against various T-cell lymphomas. First, we examined the expression of CCR4 mRNA and surface CCR4 in various T-cell lymphoma cell lines and found that it was downregulated upon treatment with vorinostat, a pan-histone deacetylase inhibitor. Next, we used isoform-specific histone deacetylase inhibitors and short-interfering RNA to determine the histone deacetylase isoform involved in the regulation of CCR4, and demonstrated that romidepsin, a class I selective histone deacetylase inhibitor, reduced CCR4 most efficiently. Moreover, among class I histone deacetylases, histone deacetylase 2 knockdown led to a reduction of CCR4 in lymphoma cells, suggesting that CCR4 expression is mainly regulated by histone deacetylase 2. When we examined the CCR4 expression in skin samples from primary cutaneous T-cell lymphoma, obtained from the same patients before and after vorinostat treatment, we found that CCR4 expression was greatly reduced after treatment. Finally, when we conducted an antibody-dependent cell-mediated cytotoxicity assay with mogamulizumab by using various lymphoma cells, we found that the efficacy of mogamulizumab was significantly reduced by pretreatment with vorinostat. Altogether, our results suggest that the primary use of histone deacetylase inhibitors before treatment with mogamulizumab might not be suitable to obtain synergistic effects. Moreover, these results have potential implications for optimal therapeutic sequences in various CCR4-positive T-cell lymphomas.

Dual strands of pre-miR‑150 (miR‑150‑5p and miR‑150‑3p) act as antitumor miRNAs targeting SPOCK1 in naïve and castration-resistant prostate cancer

Analysis of our microRNA (miRNA) expression signature in human cancers has shown that guide and passenger strands of pre-miR‑150, i.e., miR‑150‑5p and miR‑150‑3p, are significantly downregulated in cancer tissues. In miRNA biogenesis, the passenger strand of miRNA is degraded and is thought to have no functions. Thus, the aim of this study was to investigate the functional significance of miR‑150‑5p and miR‑150‑3p in naïve prostate cancer (PCa) and castration-resistant prostate cancer (CRPC). Ectopic expression assays showed that both strands of miRNAs significantly suppressed cancer cell migration and invasion. Our strategies of miRNA target searching demonstrated that SPOCK1 (SPARC/osteonectin, cwcv and kazal like domains proteoglycan 1) was directly regulated by miR‑150‑5p and miR‑150‑3p. Knockdown of SPOCK1 by siRNA inhibited cancer cell aggressiveness. Moreover, overexpression of SPOCK1 was observed in naïve PCa and CRPC tissues. Taken together, dual strands of pre-miR‑150 (miR‑150‑5p and miR‑150‑3p) acted as antitumor miRNAs in naïve PCa and CRPC cells. Expression of oncogenic SPOCK1 was involved in naïve PCa and CRPC pathogenesis. Novel approaches to analysis of antitumor miRNA-regulated RNA networks in cancer cells may provide new insights into the pathogenic mechanisms of naïve PCa and CRPC.