The role and prospect of JMJD3 in stem cells and cancer

Encapsulation of 4-oxo-N-(4-hydroxyphenyl) retinamide in human serum albumin nanoparticles promotes EZH2 degradation in preclinical neuroblastoma models

Neuroblastoma is the most prevalent and aggressive solid tumor that develops extracranially in children between the ages of 0-14 years, which accounts for 8-10% of all childhood malignancies and ∼15% of pediatric cancer-related mortality. The polycomb repressive complex 2 (PRC2) protein, EZH2, is overexpressed in neuroblastoma and mediates histone H3 methylation at lysine 27 (K27) positions through its methyl transferase activity and is a potential epigenetic silencer of many tumor suppressor genes in cancer. Phosphorylation of EZH2 decreases its stability and leads to proteasomal degradation. The 4-oxo-N-(4-hydroxyphenyl) retinamide (4O4HPR) promotes EZH2 degradation via activation of PKC-δ, but its limited solubility and physiological instability limit its application. In the current study, the encapsulation of 4O4HPR in Human Serum Albumin Nanoparticles (HSANPs) enhanced the solubility and physiological stability of the nanoformulation, leading to improved therapeutic efficacy through G2-M cell cycle arrest, depolarization of mitochondrial membrane potential, generation of reactive oxygen species and caspase 3 mediated apoptosis activation. The molecular mechanistic approach of 4O4HPR loaded HSANPs has activated caspase 3, which further cleaves PKC-δ into two fragments wherein the cleaved fragment of PKC-δ possesses the kinase activity that phosphorylates EZH2 and decreases the protein stability leading to its further ubiquitination in SH-SY5Y cells. Co-immunoprecipitation experiments revealed the direct interaction between PKC-δ and EZH2 phosphorylation, followed by ubiquitination. Moreover, 4O4HPR loaded HSANPs demonstrated improved in vivo biodistribution, greater dispersibility, and biocompatibility and exhibited enhanced protein instability and degradation of EZH2 in the neuroblastoma xenograft mouse model.

Targeting of H19/cell adhesion molecules circuitry by GSK-J4 epidrug inhibits metastatic progression in prostate cancer

BACKGROUND

About 30% of Prostate cancer (PCa) patients progress to metastatic PCa that remains largely incurable. This evidence underlines the need for the development of innovative therapies. In this direction, the potential research focus might be on long non-coding RNAs (lncRNAs) like H19, which serve critical biological functions and show significant dysregulation in cancer. Previously, we showed a transcriptional down-regulation of H19 under combined pro-tumoral estrogen and hypoxia treatment in PCa cells that, in turn, induced both E-cadherin and β4 integrin expression. H19, indeed, acts as transcriptional repressor of cell adhesion molecules affecting the PCa metastatic properties. Here, we investigated the role of H19/cell adhesion molecules circuitry on in vivo PCa experimental tumor growth and metastatic dissemination models.

METHODS

H19 was silenced in luciferase-positive PC-3 and 22Rv1 cells and in vitro effect was evaluated by gene expression, proliferation and invasion assays before and after treatment with the histone lysine demethylase inhibitor, GSK-J4. In vivo tumor growth and metastasis dissemination, in the presence or absence of GSK-J4, were analyzed in two models of human tumor in immunodeficient mice by in vivo bioluminescent imaging and immunohistochemistry (IHC) on explanted tissues. Organotypic Slice Cultures (OSCs) from fresh PCa-explant were used as ex vivo model to test GSK-J4 effects.

RESULTS

H19 silencing in both PC-3 and 22Rv1 cells increased: i) E-cadherin and β4 integrin expression as well as proliferation and invasion, ii) in vivo tumor growth, and iii) metastasis formation at bone, lung, and liver. Of note, treatment with GSK-J4 reduced lesions. In parallel, GSK-J4 efficiently induced cell death in PCa-derived OSCs.

CONCLUSIONS

Our findings underscore the potential of the H19/cell adhesion molecules circuitry as a targeted approach in PCa treatment. Modulating this interaction has proven effective in inhibiting tumor growth and metastasis, presenting a logical foundation for targeted therapy.

Antitumoral Potential of the Histone Demethylase Inhibitor GSK-J4 in Retinoblastoma

Purpose

The purpose of this study was to investigate the antitumor effects of GSK-J4 on retinoblastoma, as well as its related biological functions and molecular mechanisms.

Methods

The antitumor effect of GSK-J4 on retinoblastoma was evaluated by in vitro and in vivo assays. CCK-8, EdU incorporation, and soft agar colony formation assays were performed to examine the effect of GSK-J4 on cell proliferation. Flow cytometry was used to evaluate the effect of GSK-J4 on the cell cycle and apoptosis. RNA-seq and Western blotting were conducted to explore the molecular mechanisms of GSK-J4. An orthotopic xenograft model was established to determine the effect of GSK-J4 on tumor growth.

Results

GSK-J4 significantly inhibited retinoblastoma cell proliferation both in vitro and in vivo, arrested the cell cycle at G2/M phase, and induced apoptosis. Mechanistically, GSK-J4 may suppress retinoblastoma cell growth by regulating the PI3K/AKT/NF-κB signaling pathway.

Conclusions

The antitumor effects of GSK-J4 were noticeable in retinoblastoma and were at least partially mediated by PI3K/AKT/NF-κB pathway suppression. Our study provides a novel strategy for the treatment of retinoblastoma.

YAP represses intestinal inflammation through epigenetic silencing of JMJD3

BACKGROUND

Epigenetics plays an important role in the pathogenesis of inflammatory bowel disease (IBD). Some studies have reported that YAP is involved in inflammatory response and can regulate target genes through epigenetic modifications. JMJD3, a histone H3K27me3 demethylase, is associated with some inflammatory diseases. In this study, we investigated the role of YAP in the development of IBD and the underlying epigenetic mechanisms.

RESULTS

YAP expression was significantly increased in both in vitro and in vivo colitis models as well as in patients with IBD. Epithelial-specific knockout of YAP aggravates disease progression in dextran sodium sulfate (DSS)-induced murine colitis. In the TNF-α-activated cellular inflammation model, YAP knockdown significantly increased JMJD3 expression. Coimmunoprecipitation experiments showed that YAP and EZH2 bind to each other, and chromatin immunoprecipitation-PCR (ChIP-PCR) assay indicated that silencing of YAP or EZH2 decreases H3K27me3 enrichment on the promoter of JMJD3. Finally, administration of the JMJD3 pharmacological inhibitor GSK-J4 alleviated the progression of DSS-induced murine colitis.

CONCLUSION

Our findings elucidate an epigenetic mechanism by which YAP inhibits the inflammatory response in colitis through epigenetic silencing of JMJD3 by recruiting EZH2.

Functional and long-lived melanocytes from human pluripotent stem cells with transient ectopic expression of JMJD3

BACKGROUND

Melanocytes are an essential part of the epidermis, and their regeneration has received much attention because propagation of human adult melanocytes in vitro is too slow for clinical use. Differentiation from human pluripotent stem cells to melanocytes has been reported, but the protocols to produce them require multiple and complex differentiation steps.

METHOD

We differentiated human embryonic stem cells (hESCs) that transiently express JMJD3 to pigmented cells. We investigated whether the pigmented cells have melanocytic characteristics and functions by qRT-PCR, immunocytochemical analysis and flow cytometry. We also investigated their biocompatibility by injecting the cells into immunodeficient mice for clinical use.

RESULT

We successfully differentiated and established a pure culture of melanocytes. The melanocytes maintained their growth rate for a long time, approximately 200 days, and were functional. They exhibited melanogenesis and transfer of melanin to peripheral keratinocytes. Moreover, melanocytes simulated the developmental processes from melanoblasts to melanocytes. The melanocytes had high engraftability and biocompatibility in the immunodeficient mice.

CONCLUSION

The robust generation of functional and long-lived melanocytes are key to developing clinical applications for the treatment of pigmentary skin disorders.

Histone methyltransferase enzyme enhancer of zeste homolog 2 counteracts ischemic brain injury via H3K27me3-mediated regulation of PI3K/AKT/mTOR signaling pathway

BACKGROUND

Epigenetic histone methylation plays a crucial role in cerebral ischemic injury, particularly in the context of ischemic stroke. However, the complete understanding of regulators involved in histone methylation, such as Enhancer of Zeste Homolog 2 (EZH2), along with their functional effects and underlying mechanisms, remains incomplete.

METHODS

Here, we employed a rat model of MCAO (Middle cerebral artery occlusion) and an OGD (Oxygen-Glucose Deprivation) model of primary cortical neurons to study the role of EZH2 and H3K27me3 in cerebral ischemia-reperfusion injury. The infarct volume was measured through TTC staining, while cell apoptosis was detected using TUNEL staining. The mRNA expression levels were quantified through quantitative real-time polymerase chain reaction (qPCR), whereas protein expressions were evaluated via western blotting and immunofluorescence experiments.

RESULTS

The expression levels of EZH2 and H3K27me3 were upregulated in OGD; these expression levels were further enhanced by GSK-J4 but reduced by EPZ-6438 and AKT inhibitor (LY294002) under OGD conditions. Similar trends were observed for mTOR, AKT, and PI3K while contrasting results were noted for UTX and JMJD3. The phosphorylation levels of mTOR, AKT, and PI3K were activated by OGD, further stimulated by GSK-J4, but inhibited by EPZ-6438 and AKT inhibitor. Inhibition of EZH2 or AKT effectively counteracted OGD-/MCAO-induced cell apoptosis. Additionally, inhibition of EZH2 or AKT mitigated MCAO-induced infarct size and neurological deficit in vivo.

CONCLUSIONS

Collectively, our results demonstrate that EZH2 inhibition exerts a protective effect against ischemic brain injury by modulating the H3K27me3/PI3K/AKT/mTOR signaling pathway. The results provide novel insights into potential therapeutic mechanisms for stroke treatment.

Novel insights of EZH2-mediated epigenetic modifications in degenerative musculoskeletal diseases

Degenerative musculoskeletal diseases (Osteoporosis, Osteoarthritis, Degenerative Spinal Disease and Sarcopenia) are pathological conditions that affect the function and pain of tissues such as bone, cartilage, and muscles, and are closely associated with ageing and long-term degeneration. Enhancer of zeste homolog 2 (EZH2), an important epigenetic regulator, regulates gene expression mainly through the PRC2-dependent trimethylation of histone H3 at lysine 27 (H3K27me3). Increasing evidence suggests that EZH2 is involved in several biological processes closely related to degenerative musculoskeletal diseases, such as osteogenic-adipogenic differentiation of bone marrow mesenchymal stem cells, osteoclast activation, chondrocyte functional status, and satellite cell proliferation and differentiation, mainly through epigenetic regulation (H3K27me3). Therefore, the synthesis and elucidation of the role of EZH2 in degenerative musculoskeletal diseases have attracted increasing attention. In addition, although EZH2 inhibitors have been approved for clinical use, whether they can be repurposed for the treatment of degenerative musculoskeletal diseases needs to be considered. Here, we reviewed the role of EZH2 in the development of degenerative musculoskeletal diseases and brought forward prospects of its pharmacological inhibitors in the improvement of the treatment of the diseases.

SPOCK2 and SPRED1 function downstream of EZH2 to impede the malignant progression of lung adenocarcinoma in vitro and in vivo

Enhancer of zeste homolog 2 (EZH2) is an important epigenetic regulator, and is associated with the malignant progression of lung cancer. However, the mechanisms of EZH2 on lung adenocarcinoma (LUAD) remain unclear. The relationship between EZH2 and SPOCK2 or SPRED1 was confirmed by dual-luciferase reporter assay. The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were analyzed to examine the expression of SPOCK2 and SPRED1 and their prognostic values of LUAD. The effects of SPOCK2 and SPRED1 on the biological characters of LUAD cells were identified on functional assays in vitro and in vivo. Our results showed that EZH2 suppressed the expression and transcriptional activity of SPOCK2 and SPRED1, and these effects were reversed by the EZH2 inhibitor, Tazemetostat. SPOCK2 and SPRED1 were expressed at low levels in LUAD patients, and a high expression level of SPOCK2 or SPRED1 predicted better survival. Moreover, overexpression of SPOCK2 or SPRED1 could inhibit tumoral proliferation, migration ratio, and invasion activity in vitro as well as retard tumor growth in vivo. However, EZH2 elevation could rescue these impacts and accelerate LUAD progression. Our findings reveal that SPOCK2 and SPRED1 are epigenetically suppressed by EZH2 and may act as novel regulators to inhibit the proliferation, migration, and invasion of LUAD cells.

Discovery of cysteine-targeting covalent histone methyltransferase inhibitors

Post-translational methylation of histone lysine or arginine residues by histone methyltransferases (HMTs) plays crucial roles in gene regulation and diverse physiological processes and is implicated in a plethora of human diseases, especially cancer. Therefore, histone methyltransferases have been increasingly recognized as potential therapeutic targets. Consequently, the discovery and development of histone methyltransferase inhibitors have been pursued with steadily increasing interest over the past decade. However, the disadvantages of limited clinical efficacy, moderate selectivity, and propensity for acquired resistance have hindered the development of HMTs inhibitors. Targeted covalent modification represents a proven strategy for kinase drug development and has gained increasing attention in HMTs drug discovery. In this review, we focus on the discovery, characterization, and biological applications of covalent inhibitors for HMTs with emphasis on advancements in the field. In addition, we identify the challenges and future directions in this fast-growing research area of drug discovery.

Multi-therapies Based on PARP Inhibition: Potential Therapeutic Approaches for Cancer Treatment

The nuclear enzymes called poly(ADP-ribose)polymerases (PARPs) are known to catalyze the process of PARylation, which plays a vital role in various cellular functions. They have become important targets for the discovery of novel antitumor drugs since their inhibition can induce significant lethality in tumor cells. Therefore, researchers all over the world have been focusing on developing novel and potent PARP inhibitors for cancer therapy. Studies have shown that PARP inhibitors and other antitumor agents, such as EZH2 and EGFR inhibitors, play a synergistic role in cancer cells. The combined inhibition of PARP and the targets with synergistic effects may provide a rational strategy to improve the effectiveness of current anticancer regimens. In this Perspective, we sum up the recent advance of PARP-targeted agents, including single-target inhibitors/degraders and dual-target inhibitors/degraders, discuss the fundamental theory of developing these dual-target agents, and give insight into the corresponding structure-activity relationships of these agents.

Emerging role of EZH2 in rheumatic diseases: A comprehensive review

Enhancer of zeste homolog 2 (EZH2) is a histone methylated enzyme. It trimethylates histone 3 lysine 27 (H3K27) to regulate epigenetic processes. Recently, studies showed excessive expression of EZH2 in rheumatic diseases, such as systemic lupus erythematosus, rheumatoid arthritis, osteoarthritis, and systemic sclerosis. Moreover, epigenetic modification of EZH2 regulates differentiation and proliferation of different immune cells. Therefore, in this review, we comprehensively discuss the role of EZH2 in rheumatic diseases. Collection of the evidence may provide a basis for further understanding the role of EZH2 and give potential for targeting these diseases.

BMP2 inhibits cell proliferation by downregulating EZH2 in gastric cancer

Gastric cancer is among the most common gastrointestinal malignancies. Recent studies have suggested that bone morphogenetic protein-2 (BMP2) is related to the development and progression of various cancers. Meanwhile, evidence suggests that BMP2 might lead to epigenetic changes in gastric cancer. Thus, we investigated whether BMP2 plays a role in the development of gastric cancer via epigenetic regulation. Cell viability, colony formation, and cell cycle assays were performed to assess the effect of recombinant human BMP2 (rhBMP2) in gastric cancer cells. LDN-193189 and Noggins were used as antagonists of the canonical BMP-SMAD signaling pathway. The protein levels were determined using a western blot analysis. Lentiviral vectors with EZH2 shRNA or EZH2 overexpression were used to mediate the role of EZH2 and the relationship between BMP2 and EZH2 in gastric cancer. We found that rhBMP2 inhibits cell proliferation by arresting the cell cycle in HGC-27 and SNU-216 gastric cancer cells. Neither LDN-193189 nor Noggins, antagonists of the canonical BMP-SMAD signaling pathway, can reverse the effect of rhBMP2 on gastric cancer. Molecularly, rhBMP2 downregulates the expression of EZH2 and H3K27me3, leading to increases in P16 and P21 and decreases in CDK2, CDK4, and CDK6. Altogether, in this study, we demonstrate that BMP2 serves as a tumor suppressor in gastric cancer cells by downregulating EZH2 and H3K27me3 through the non-SMAD BMP pathway, suggesting that BMP2 might be a new therapeutic target for gastric cancer treatment. Abbreviations: BMP: bone morphogenetic protein; TGF-β: transforming growth factor-beta; EZH2: enhancer of zeste homolog 2; H3K27me3: trimethylation histone H3 lysine 27; HRECs: human retinal endothelial cells; PcG: polycomb group; PRC: polycomb repressive complexes.

JMJD3 suppresses tumor progression in oral tongue squamous cell carcinoma patients receiving surgical resection

Background

Jumonji domain-containing-3 (JMJD3) is reported to be a histone H3 lysine 27 (H3K27) demethylase and a tumor suppressor gene. The present study designed to investigate the crucial role of JMJD3 in oral tongue squamous cell carcinoma (OTSCC) patients who received surgical resection.

Methods

We enrolled a total of 156 OTSCC patients receiving surgical resection, including 73 patients (47%) with high expression of JMJD3 and 83 patients (53%) harboring low expression of JMJD3. Two OTSCC cell lines, SAS and Cal 27, were used to explore the modulation of cancer. GSK-J4, a potent inhibitor of JMJD3, was used to treat the two OTSCC cell lines. The Chi-square test was performed to examine between-group differences in categorical variables; the Kaplan-Meier method was used to investigate survival outcome in univariate analysis, and the Cox regression model was used for multivariate analysis.

Results

The median follow-up period was 59.2 months and he five-year disease-free survival (DFS) and overall survival (OS) rates were 46.2% and 50.0%, respectively. Better five-year DFS (59% versus 35%) and five-year OS (63% versus 39%) were mentioned in patients with high expression of JMJD3 compared to those with low expression of JMJD3. High expression of JMJD3 was significantly associated with superior DFS and OS in the univariate and multivariate analyses. Following successful inhibition of JMJD3 by GSK-J4, western blotting analysis showed the decreased expression of Rb and p21.

Conclusion

Our study showed that high expression of JMJD3 is a good prognostic factor in OTSCC patients who underwent surgical resection.

Emerging roles of JMJD3 in cancer

Histone lysine methylation plays a key role in gene activation and repression. The trimethylation of histone H3 on lysine-27 (H3K27me3) is a critical epigenetic event that is controlled by Jumonji domain-containing protein-3 (JMJD3). JMJD3 is a histone demethylase that specifically removes methyl groups. Previous studies have suggested that JMJD3 has a dual role in cancer cells. JMJD3 stimulates the expression of proliferative-related genes and increases tumor cell growth, propagation, and migration in various cancers, including neural, prostate, ovary, skin, esophagus, leukemia, hepatic, head and neck, renal, lymphoma, and lung. In contrast, JMJD3 can suppress the propagation of tumor cells, and enhance their apoptosis in colorectal, breast, and pancreatic cancers. In this review, we summarized the recent advances of JMJD3 function in cancer cells.

The correlation of EZH2 expression with the progression and prognosis of hepatocellular carcinoma

Background

Enhancer of Zeste homologue 2 (EZH2) is a polycomb group gene and an epigenetic regulator that inhibits transcription, a modification associated with gene silencing. EZH2 plays an essential role in humoral and cell-mediated adaptive immunity. The purpose of the current study is to investigate the prognostic potential of EZH2 and to comprehensively analyse the correlation between EZH2 and immune infiltration in multiple cancer cases, especially liver hepatocellular carcinoma.

Methods

EZH2 expression across cancers was explored through Oncomine, HPA, and GEPIA2. Additionally, the prognostic value of EZH2 analysis across cancers was based on the GEPIA2, TCGA portal, Kaplan–Meier Plotter, and LOGpc databases. Based on GO and KEGG analyses, GSEA helped demonstrate the biological processes through which EZH2 might lead to HCC development. GEPIA and TIMER were adopted to detect the possible relationship of EZH2 expression with tumour-infiltrating immune cells (TIICs).

Results

EZH2 overexpression levels were associated with poor prognosis of cancer, especially hepatocellular carcinoma. A high EZH2 expression level is related to a poor prognosis of HCC, especially in disease histology and stage III. The EZH2 expression level was positively correlated with critical gene markers of TAMs, M2 macrophages, M1 macrophages, and monocytes. Further analysis revealed that EZH2 genes were mainly related to DNA recombination, mitotic cell cycle phase transition, and chromosome segregation.

Conclusion

EZH2 plays an essential role in the immune microenvironment and is a potential prognostic marker and immunotherapy target for hepatocellular carcinoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-022-00502-7.

GSK-J4, a Specific Histone Lysine Demethylase 6A Inhibitor, Ameliorates Lipotoxicity to Cardiomyocytes via Preserving H3K27 Methylation and Reducing Ferroptosis

Changes in modern lifestyle provoke a series of metabolic stresses such as hyperlipidemia. Excessive free fatty acids induce cardiomyocyte metabolic reprogramming and rearrangement of the lipid content of cardiomyocyte and promote oxidative stress. As a newly defined lipid peroxidation-related cell death pathway, the role of ferroptosis in metabolic stress-induced cardiomyocyte injury is poorly revealed. Our work indicates that GSK-J4, a histone lysine demethylase 6A/6B dual inhibitor, can alleviate palmitic acid (PA)-induced hypersensitivity to ferroptosis by suppressing H3K27 demethylation. Mechanistically, PA stimulation reduces the H3K27me3 level and hence promotes the expression of ACSL4, a key lipid modulator of ferroptosis. GSK-J4 pretreatment significantly preserves the H3K27me3 level and reduces the ACSL4 level. GSK-J4 also reduces reactive oxygen species to alleviate oxidative stress, which further decreases lipid peroxidation. Taken together, our data suggest that cardiomyocyte undergoes epigenetic reprogramming under metabolic challenges, rearranging lipid content, and sensitizing to ferroptosis. GSK-J4 can be a potential drug for treating hyperlipidemia-induced cardiomyocyte injury by targeting epigenetic modulations.

α-Ketoglutaric acid ameliorates hyperglycemia in diabetes by inhibiting hepatic gluconeogenesis via serpina1e signaling

Previously, we found that α-ketoglutaric acid (AKG) stimulates muscle hypertrophy and fat loss through 2-oxoglutarate receptor 1 (OXGR1). Here, we demonstrated the beneficial effects of AKG on glucose homeostasis in a diet-induced obesity (DIO) mouse model, which are independent of OXGR1. We also showed that AKG effectively decreased blood glucose and hepatic gluconeogenesis in DIO mice. By using transcriptomic and liver-specific serpina1e deletion mouse model, we further demonstrated that liver serpina1e is required for the inhibitory effects of AKG on hepatic gluconeogenesis. Mechanistically, we supported that extracellular AKG binds with a purinergic receptor, P2RX4, to initiate the solute carrier family 25 member 11 (SLC25A11)-dependent nucleus translocation of intracellular AKG and subsequently induces demethylation of lysine 27 on histone 3 (H3K27) in the seprina1e promoter region to decrease hepatic gluconeogenesis. Collectively, these findings reveal an unexpected mechanism for control of hepatic gluconeogenesis using circulating AKG as a signal molecule.

Targeting Epigenetic Regulatory Enzymes for Cancer Therapeutics: Novel Small-Molecule Epidrug Development

Dysregulation of the epigenetic enzyme-mediated transcription of oncogenes or tumor suppressor genes is closely associated with the occurrence, progression, and prognosis of tumors. Based on the reversibility of epigenetic mechanisms, small-molecule compounds that target epigenetic regulation have become promising therapeutics. These compounds target epigenetic regulatory enzymes, including DNA methylases, histone modifiers (methylation and acetylation), enzymes that specifically recognize post-translational modifications, chromatin-remodeling enzymes, and post-transcriptional regulators. Few compounds have been used in clinical trials and exhibit certain therapeutic effects. Herein, we summarize the classification and therapeutic roles of compounds that target epigenetic regulatory enzymes in cancer treatment. Finally, we highlight how the natural compounds berberine and ginsenosides can target epigenetic regulatory enzymes to treat cancer.

Exploring Methods of Targeting Histone Methyltransferases and Their Applications in Cancer Therapeutics

Histone methyltransferases (HMTs) are enzymes that catalyze the methylation of lysine or arginine residues of histone proteins, a key post-translational modification (PTM). Aberrant expression or activity of these enzymes can lead to abnormal histone methylation of cancer-related genes and thus promote tumorigenesis. Histone methyltransferases have been implicated in chemotherapeutic resistance and immune stimulation, making these enzymes potential therapeutic targets of interest, and chemically targeting these proteins provides an avenue for novel drug development in cancer therapy. This Review aims to discuss the evolution of chemical approaches that have emerged in the past five years to design probes targeting these enzymes, including inhibition through noncovalent inhibitors, covalent inhibitors, and targeted protein degradation through proteolysis targeting chimeras (PROTACs). This Review also highlights how these compounds have been used to study the myriad of HMT functions in cancer progression and treatment response. The recent advancement of some of these drugs into human clinical investigation and even to regulatory approval highlights HMTs as a promising class of targets for chemical intervention and novel therapy development.

Inhibition of Histone H3 Lysine-27 Demethylase Activity Relieves Rheumatoid Arthritis Symptoms via Repression of IL6 Transcription in Macrophages

Rheumatoid arthritis (RA) occurs in about 5 per 1,000 people and can lead to severe joint damage and disability. However, the knowledge of pathogenesis and treatment for RA remains limited. Here, we found that histone demethylase inhibitor GSK-J4 relieved collagen induced arthritis (CIA) symptom in experimental mice model, and the underlying mechanism is related to epigenetic transcriptional regulation in macrophages. The role of epigenetic regulation has been introduced in the process of macrophage polarization and the pathogenesis of inflammatory diseases. As a repressive epigenetic marker, tri-methylation of lysine 27 on histone H3 (H3K27me3) was shown to be important for transcriptional gene expression regulation. Here, we comprehensively analyzed H3K27me3 binding promoter and corresponding genes function by RNA sequencing in two differentially polarized macrophage populations. The results revealed that H3K27me3 binds on the promoter regions of multiple critical cytokine genes and suppressed their transcription, such as IL6, specifically in M-CSF derived macrophages but not GM-CSF derived counterparts. Our results may provide a new approach for the treatment of inflammatory and autoimmune disorders.

KDM6 Demethylases and Their Roles in Human Cancers

Cancer therapy is moving beyond traditional chemotherapy to include epigenetic approaches. KDM6 demethylases are dynamic regulation of gene expression by histone demethylation in response to diverse stimuli, and thus their dysregulation has been observed in various cancers. In this review, we first briefly introduce structural features of KDM6 subfamily, and then discuss the regulation of KDM6, which involves the coordinated control between cellular metabolism (intrinsic regulators) and tumor microenvironment (extrinsic stimuli). We further describe the aberrant functions of KDM6 in human cancers, acting as either a tumor suppressor or an oncoprotein in a context-dependent manner. Finally, we propose potential therapy of KDM6 enzymes based on their structural features, epigenetics, and immunomodulatory mechanisms, providing novel insights for prevention and treatment of cancers.

JMJD3: a critical epigenetic regulator in stem cell fate

The Jumonji domain-containing protein-3 (JMJD3) is a histone demethylase that regulates the trimethylation of histone H3 on lysine 27 (H3K27me3). H3K27me3 is an important epigenetic event associated with transcriptional silencing. JMJD3 has been studied extensively in immune diseases, cancer, and tumor development. There is a comprehensive epigenetic transformation during the transition of embryonic stem cells (ESCs) into specialized cells or the reprogramming of somatic cells to induced pluripotent stem cells (iPSCs). Recent studies have illustrated that JMJD3 plays a major role in cell fate determination of pluripotent and multipotent stem cells (MSCs). JMJD3 has been found to enhance self-renewal ability and reduce the differentiation capacity of ESCs and MSCs. In this review, we will focus on the recent advances of JMJD3 function in stem cell fate.

Histone demethylase KDM6B inhibits breast cancer metastasis by regulating Wnt/β-catenin signaling

Tumor metastasis remains a major challenge for patients with breast cancer. Aberrant epigenetic factor lysine‐specific demethylase 6B (KDM6B) has been associated with tumor progression. Here, we show that KDM6B is significantly down‐regulated in human breast cancer tissues, and its low expression is associated with poor prognosis of patients with breast cancer. Furthermore, overexpression of KDM6B remarkably inhibited cell proliferation, invasion, migration and epithelial–mesenchymal transition markers of breast cancer cells in vitro and tumor growth and lung metastasis in vivo. Notably, the expression of KDM6B in breast cancer tissues was negatively correlated with that of β‐catenin, and overexpression of KDM6B decreased the expression of β‐catenin and its accumulation in the nucleus of breast cancer cells. Overall, our findings provide novel insights into suppression of metastasis of breast cancer cells by KDM6B via β‐catenin and suggest involvement of the KDM6B‐Wnt/β‐catenin axis in breast cancer progression.

Inhibition of enhancer of zeste homolog 2 prevents corneal myofibroblast transformation in vitro

PURPOSE

Corneal fibroblast can be transformed into corneal myofibroblasts by TGF-β1. Enhancer of zeste homolog 2 (EZH2) upregulation has been observed in the occurrence of other fibrotic disorders. We investigated the role of EZH2 in the progression of corneal fibrosis and the antifibrotic effect of EZH2 inhibition in corneal fibroblasts (CFs).

METHODS

Primary CFs were isolated from corneal limbi and the CFs were treated with TGF-β1 to induce fibrosis. EPZ-6438 and EZH2 siRNA were used to inhibit EZH2 expression. Myofibroblast activation and extracellular matrix (ECM) protein synthesis was detected by quantitative real-time PCR, western blotting, and immunofluorescence staining assay. The functions of myofibroblast were evaluated by cell migration and collagen gel contraction assays. Molecular mechanisms involved in EZH2 inhibition were investigated by RNA sequencing.

RESULTS

TGF-β1 activated EZH2 expression in CFs. Treatment with EPZ-6438 (5 μM) and EZH2 siRNA considerably suppressed corneal myofibroblast activation and ECM protein synthesis in CFs induced by TGF-β1 when compared to the control group. EPZ-6438 (5 μM) suppressed cell migration and gel contraction in CFs. RNA sequencing results revealed that antifibrotic genes were activated after EZH2 inhibition to suppress corneal myofibroblast activation.

CONCLUSION

Inhibition of EZH2 suppresses corneal myofibroblast activation and ECM protein synthesis, and could serve as a novel therapeutic target for preventing corneal scarring.

Reciprocal regulation of pancreatic ductal adenocarcinoma growth and molecular subtype by HNF4α and SIX1/4

OBJECTIVE

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a 5-year survival of less than 5%. Transcriptomic analysis has identified two clinically relevant molecular subtypes of PDAC: classical and basal-like. The classical subtype is characterised by a more favourable prognosis and better response to chemotherapy than the basal-like subtype. The classical subtype also expresses higher levels of lineage specifiers that regulate endodermal differentiation, including the nuclear receptor hepatocyte nuclear factor 4 α (HNF4α). The objective of this study is to evaluate the role of HNF4α, SIX4 and SIX1 in regulating the growth and molecular subtype of PDAC.

DESIGN

We manipulate the expression of HNF4α, SIX4 and SIX1 in multiple in vitro and in vivo PDAC models. We determine the consequences of manipulating these genes on PDAC growth, differentiation and molecular subtype using functional assays, gene expression analysis and cross-species comparisons with human datasets.

RESULTS

We show that HNF4α restrains tumour growth and drives tumour cells toward an epithelial identity. Gene expression analysis of murine models and human tumours shows that HNF4α activates expression of genes associated with the classical subtype. HNF4α also directly represses SIX4 and SIX1, two mesodermal/neuronal lineage specifiers expressed in the basal-like subtype. Finally, SIX4 and SIX1 drive proliferation and regulate differentiation in HNF4α-negative PDAC.

CONCLUSION

Our data show that HNF4α regulates the growth and molecular subtype of PDAC by multiple mechanisms, including activation of the classical gene expression programme and repression of SIX4 and SIX1, which may represent novel dependencies of the basal-like subtype.

Expression pattern of histone lysine-specific demethylase 6B in gastric cancer

Over the last few decades, predictive markers for the prognosis of gastric cancer have not been extensively investigated. The present study aimed to evaluate the expression profile of histone demethylase lysine (K)-specific demethylase 6B (KDM6B) in gastric cancer and healthy control tissues, as well as its value in prognosis prediction as a clinical marker. Within the framework of these criteria, the diagnostic role of KMD6B for gastric cancer was investigated, which may provide insights into novel treatment targets. Immunohistochemistry was applied to detect KMD6B expression in 100 gastric cancer tissues and matching para-cancerous tissues to analyze the association between KMD6B expression and clinicopathological features. Based on the follow-up data, the value of KMD6B in prognosis assessment was further explored. The role of KMD6B in gastric cancer cell proliferation, cell cycle distribution and the expression of cell cycle-associated proteins was investigated by inhibiting KMD6B activity using the specific inhibitor GSK J4. KMD6B was mostly distributed in cytoplasm and nucleus in gastric cancer tissue. The expression level was significantly higher in cancer tissues compared with that in the corresponding non-cancerous tissues. The expression of KMD6B was significantly associated with sex, lymph node and distant metastasis status and clinical stage (P<0.05). Cell proliferation was significantly decreased with the inhibition of KMD6B activity, and the cell cycle in HGC27 cells was arrested in the G₂/M phase after being treated with GSK J4 for 24 h. The expression of cyclin B and Cdc2 were significantly decreased, while p21 was upregulated. It was concluded that the dysregulated expression of KMD6B is associated with the malignant progression of gastric cancer and could be a potential marker for prognosis. Blocking the demethylase activity of KMD6B induced G₂/M arrest and inhibited the proliferation of gastric cancer cells, suggesting that KMD6B is a potential novel therapeutic target for gastric cancer.

Inhibition of the Histone Methyltransferase EZH2 Enhances Protumor Monocyte Recruitment in Human Mesothelioma Spheroids

Malignant pleural mesothelioma (MPM) is a highly aggressive cancer with a long latency period and dismal prognosis. Recently, tazemetostat (EPZ-6438), an inhibitor of the histone methyltransferase EZH2, has entered clinical trials due to the antiproliferative effects reported on MPM cells. However, the direct and indirect effects of epigenetic reprogramming on the tumor microenvironment are hitherto unexplored. To investigate the impact of tumor-associated macrophages (TAMs) on MPM cell responsiveness to tazemetostat, we developed a three-dimensional MPM spheroid model that recapitulates in vitro, both monocytes’ recruitment in tumors and their functional differentiation toward a TAM-like phenotype (Mo-TAMs). Along with an increased expression of genes for monocyte chemoattractants, inhibitory immune checkpoints, immunosuppressive and M2-like molecules, Mo-TAMs promote tumor cell proliferation and spreading. Prolonged treatment of MPM spheroids with tazemetostat enhances both the recruitment of Mo-TAMs and the expression of their protumor phenotype. Therefore, Mo-TAMs profoundly suppress the antiproliferative effects due to EZH2 inhibition in MPM cells. Overall, our findings indicate that TAMs are a driving force for MPM growth, progression, and resistance to tazemetostat; therefore, strategies of TAM depletion might be evaluated to improve the therapeutic efficacy of pharmacological inhibition of EZH2.

Unlocking the Recovery Potential: JMJD3 Inhibition-Mediated SAPK/JNK Signaling Inactivation Supports Endogenous Oligodendrocyte-Lineage Commitment Post Mammalian Spinal Cord Injury

Spinal cord injury (SCI) induced catastrophic neurological disability is often incurable at present. The injury triggered immediately oligodendrocytes loss and overwhelming demyelination are regarded as an insurmountable barrier to SCI recovery. To date, effective strategy to promote the endogenous oligodendrocytes replacement post SCI remains elusive. Epigenetic modifications are emerging as critical molecular switches of gene expression in CNS. However, the epigenetic mechanisms underlying oligodendrogenesis post SCI yet to be discovered. In this study, we report that H3K27me3 demethylase JMJD3 exists as a pivotal epigenetic regulator which manipulates the endogenous oligodendrogenesis post SCI. We found that JMJD3 inhibition promotes the oligodendrocyte linage commitment of neural stem/progenitor cells (NPCs) in vitro and in vivo. Moreover, we demonstrated that JMJD3 inhibition mediated SAPK/JNK signaling inactivation is functionally necessary for endogenous oligodendrocyte-lineage commitment post SCI. Our results also suggested that JMJD3 is downstream of SAPK/JNK pathway, and capable of translates SCI induced SAPK/JNK signaling into epigenetic codes readable by spinal cord endogenous NPCs. Taken together, our findings provide novel evidence of JMJD3 mediated oligodendrocyte-lineage commitment orchestration post SCI, which would be a potential epigenetic approach to induce the mature mammalian endogenous recovery.

Inhibition of macrophage histone demethylase JMJD3 protects against abdominal aortic aneurysms

Abdominal aortic aneurysms (AAAs) are a life-threatening disease for which there is a lack of effective therapy preventing aortic rupture. During AAA formation, pathological vascular remodeling is driven by macrophage infiltration, and the mechanisms regulating macrophage-mediated inflammation remain undefined. Recent evidence suggests that an epigenetic enzyme, JMJD3, plays a critical role in establishing macrophage phenotype. Using single-cell RNA sequencing of human AAA tissues, we identified increased JMJD3 in aortic monocyte/macrophages resulting in up-regulation of an inflammatory immune response. Mechanistically, we report that interferon-β regulates Jmjd3 expression via JAK/STAT and that JMJD3 induces NF-κB–mediated inflammatory gene transcription in infiltrating aortic macrophages. In vivo targeted inhibition of JMJD3 with myeloid-specific genetic depletion (JMJD3^f/fLyz2^Cre+) or pharmacological inhibition in the elastase or angiotensin II–induced AAA model preserved the repressive H3K27me3 on inflammatory gene promoters and markedly reduced AAA expansion and attenuated macrophage-mediated inflammation. Together, our findings suggest that cell-specific pharmacologic therapy targeting JMJD3 may be an effective intervention for AAA expansion.

A KDM6 inhibitor potently induces ATF4 and its target gene expression through HRI activation and by UTX inhibition

UTX/KDM6A encodes a major histone H3 lysine 27 (H3K27) demethylase, and is frequently mutated in various types of human cancers. Although UTX appears to play a crucial role in oncogenesis, the mechanisms involved are still largely unknown. Here we show that a specific pharmacological inhibitor of H3K27 demethylases, GSK-J4, induces the expression of transcription activating factor 4 (ATF4) protein as well as the ATF4 target genes (e.g. PCK2, CHOP, REDD1, CHAC1 and TRIB3). ATF4 induction by GSK-J4 was due to neither transcriptional nor post-translational regulation. In support of this view, the ATF4 induction was almost exclusively dependent on the heme-regulated eIF2α kinase (HRI) in mouse embryonic fibroblasts (MEFs). Gene expression profiles with UTX disruption by CRISPR-Cas9 editing and the following stable re-expression of UTX showed that UTX specifically suppresses the expression of the ATF4 target genes, suggesting that UTX inhibition is at least partially responsible for the ATF4 induction. Apoptosis induction by GSK-J4 was partially and cell-type specifically correlated with the activation of ATF4-CHOP. These findings highlight that the anti-cancer drug candidate GSK-J4 strongly induces ATF4 and its target genes via HRI activation and raise a possibility that UTX might modulate cancer formation by regulating the HRI-ATF4 axis.

microRNA-27b shuttled by mesenchymal stem cell-derived exosomes prevents sepsis by targeting JMJD3 and downregulating NF-κB signaling pathway

Background

Exosomal microRNAs (miRs) derived from mesenchymal stem cells (MSCs) have been shown to play roles in the pathophysiological processes of sepsis. Moreover, miR-27b is highly enriched in MSC-derived exosomes. Herein, we aimed to investigate the potential role and downstream molecular mechanism of exosomal miR-27b in sepsis.

Methods

Inflammation was induced in bone marrow-derived macrophages (BMDMs) by lipopolysaccharide (LPS), and mice were made septic by cecal ligation and puncture (CLP). The expression pattern of miR-27b in MSC-derived exosomes was characterized using RT-qPCR, and its downstream gene was predicted by in silico analysis. The binding affinity between miR-27b, Jumonji D3 (JMJD3), or nuclear factor κB (NF-κB) was characterized to identify the underlying mechanism. We induced miR-27b overexpression or downregulation, along with silencing of JMJD3 or NF-κB to examine their effects on sepsis. The production of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6 was detected by ELISA.

Results

miR-27b was highly expressed in MSC-derived exosomes. Mechanistic investigations showed that miR-27b targeted JMJD3. miR-27b decreased expression of pro-inflammatory genes by inhibiting the recruitment of JMJD3 and NF-κB at gene promoter region. Through this, MSC-derived exosomal miR-27b diminished production of pro-inflammatory cytokines in LPS-treated BMDMs and septic mice, which could be rescued by upregulation of JMJD3 and NF-κB. Besides, in vitro findings were reproduced by in vivo findings.

Conclusion

These data demonstrated that exosomal miR-27b derived from MSCs inhibited the development of sepsis by downregulating JMJD3 and inactivating the NF-κB signaling pathway.

Causes, effects, and clinical implications of perturbed patterns within the cancer epigenome

Somatic mutations accumulating over a patient's lifetime are well-defined causative factors that fuel carcinogenesis. It is now clear, however, that epigenomic signature is also largely perturbed in many malignancies. These alterations support the transcriptional program crucial for the acquisition and maintenance of cancer hallmarks. Epigenetic instability may arise due to the genetic mutations or transcriptional deregulation of the proteins implicated in epigenetic signaling. Moreover, external stimulation and physiological aging may also participate in this phenomenon. The epigenomic signature is frequently associated with a cell of origin, as well as with tumor stage and differentiation, which all reflect its high heterogeneity across and within various tumors. Here, we will overview the current understanding of the causes and effects of the altered and heterogeneous epigenomic landscape in cancer. We will focus mainly on DNA methylation and post-translational histone modifications as the key regulatory epigenetic signaling marks. In addition, we will describe how this knowledge is translated into the clinic. We will particularly concentrate on the applicability of epigenetic alterations as biomarkers for improved diagnosis, prognosis, and prediction. Finally, we will also review current developments regarding epi-drug usage in clinical and experimental settings.

Identification of disulfiram as a potential antifungal drug by screening small molecular libraries

OBJECTIVES

Candida albicans and Candida auris strains are common causative species of Candidiasis. The limited number of antifungal drugs and the current situation of resistance to existing antifungals force us to search for new antifungal alternatives.

METHODS

In this work, primary screening of small molecule libraries (Metabolism Compound Library and Epigenetics Compound Library) consisting of 584 compounds against Candida albicans SC5314 was performed. The dose-response assays, XTT assays, scanning electron microscopy and confocal laser scanning microscopy were used to confirm the antifungal activities of the selected compounds against Candida strains.

RESULTS

Through the primary screening, we identified five compounds (U73122, disulfiram, BSK805, BIX01294, and GSKJ4) that inhibited strains growth ≥ 80% for dose-response assays. Disulfiram was identified as the most potent repositionable antifungal drug with 50% growth inhibition detected at a concentration as low as 1 mg/L. The further results showed the antifungal activity of disulfiram against biofilm formation of Candida strains with a 50% minimum inhibitory concentration ranging from 32 to 128 mg/L. Further observations by scanning electron microscopy and confocal laser scanning microscopy confirmed the destruction of biofilm architecture and the change of biofilm morphology after being exposed to disulfiram.

CONCLUSION

The study indicated the potential clinical application of disulfiram as a promising antifungal drug against candidiasis.

Regulating Methylation at H3K27: A Trick or Treat for Cancer Cell Plasticity

Properly timed addition and removal of histone 3 lysine 27 tri-methylation (H3K27me3) is critical for enabling proper differentiation throughout all stages of development and, likewise, can guide carcinoma cells into altered differentiation states which correspond to poor prognoses and treatment evasion. In early embryonic stages, H3K27me3 is invoked to silence genes and restrict cell fate. Not surprisingly, mutation or altered functionality in the enzymes that regulate this pathway results in aberrant methylation or demethylation that can lead to malignancy. Likewise, changes in expression or activity of these enzymes impact cellular plasticity, metastasis, and treatment evasion. This review focuses on current knowledge regarding methylation and de-methylation of H3K27 in cancer initiation and cancer cell plasticity.

Targeted inhibition of KDM6 histone demethylases eradicates tumor-initiating cells via enhancer reprogramming in colorectal cancer

Tumor-initiating cells (TICs) maintain heterogeneity within tumors and seed metastases at distant sites, contributing to therapeutic resistance and disease recurrence. In colorectal cancer (CRC), strategy that effectively eradicates TICs and is of potential value for clinical use still remains in need. Methods: The anti-tumorigenic activity of a small-molecule inhibitor of KDM6 histone demethylases named GSK-J4 in CRC was evaluated by in vitro assays and in vivo imaging of xenografted tumors. Sphere formation, flow cytometry analysis of cell surface markers and intestinal organoid formation were performed to examine the impact of GSK-J4 on TIC properties. Transcriptome analysis and global profiling of H3K27ac, H3K27me3, and KDM6A levels by ChIP-seq were conducted to elucidate how KDM6 inhibition reshapes epigenetic landscape and thereby eliminating TICs. Results: GSK-J4 alleviated the malignant phenotypes of CRC cells in vitro and in vivo, sensitized them to chemotherapeutic treatment, and strongly repressed TIC properties and stemness-associated gene signatures in these cells. Mechanistically, KDM6 inhibition induced global enhancer reprogramming with a preferential impact on super-enhancer-associated genes, including some key genes that control stemness in CRC such as ID1. Besides, expression of both Kdm6a and Kdm6b was more abundant in mouse intestinal crypt when compared with upper villus and inhibition of their activities blocked intestinal organoid formation. Finally, we unveiled the power of KDM6B in predicting both the overall survival outcome and recurrence of CRC patients. Conclusions: Our study provides a novel rational strategy to eradicate TICs through reshaping epigenetic landscape in CRC, which might also be beneficial for optimizing current therapeutics.

EZH2: a novel target for cancer treatment

Enhancer of zeste homolog 2 (EZH2) is enzymatic catalytic subunit of polycomb repressive complex 2 (PRC2) that can alter downstream target genes expression by trimethylation of Lys-27 in histone 3 (H3K27me3). EZH2 could also regulate gene expression in ways besides H3K27me3. Functions of EZH2 in cells proliferation, apoptosis, and senescence have been identified. Its important roles in the pathophysiology of cancer are now widely concerned. Therefore, targeting EZH2 for cancer therapy is a hot research topic now and different types of EZH2 inhibitors have been developed. In this review, we summarize the structure and action modes of EZH2, focusing on up-to-date findings regarding the role of EZH2 in cancer initiation, progression, metastasis, metabolism, drug resistance, and immunity regulation. Furtherly, we highlight the advance of targeting EZH2 therapies in experiments and clinical studies.