Epigenetic cues regulating airway development in human lung organoids: Polycomb repressive complex 2 and altered chromatin accessibility determine cell fate.

Today, human organoids are becoming an integrated part of genomics and epigenomics, as they provide a platform that can be used for the definite study of molecular and cellular mechanisms occurring at different stages of development, particularly organogenesis, within the human body. Airway development is a complex process heavily influenced by epigenetic regulatory mechanisms in response to environmental changes, and as such, human lung organoids are an indispensable asset for further exploration of these mechanisms as a mode of transition from human in vitro to human ex vivo studies. Cultured primarily in compounds mimicking the extracellular matrix, such as Matrigel, these lung organoids have helped us to come to a better understanding of the role of polycomb repressive complex 2 (PRC2) and enhancer of zeste homolog 2 (EZH2) in lung epithelial cell differentiation and airway development, which was first reported in the FASEB journal in 2019. The following is an extended account of how the histone methylation-regulating PRC2 comes to play in the molding of the human bronchial tree, along with further epigenetic insights based on more recently developed human lung organoids.

Pharmacological inhibition of EZH2 using a covalent inhibitor suppresses human ovarian cancer cell migration and invasion.

Metastasis is the cause of poor prognosis in ovarian cancer (OC). Enhancer of Zeste homolog 2 (EZH2), a histone-lysine N-methyltransferase enzyme, promotes OC cell migration and invasion by regulating the expression of tissue inhibitor of metalloproteinase-2 (TIMP2) and matrix metalloproteinases-9 (MMP9). Hence, we speculated that EZH2-targeting therapy might suppress OC migration and invasion. In this study, the expression of EZH2, TIMP2, and MMP9 in OC tissues and cell lines was analyzed using The Cancer Genome Atlas (TCGA) database and western blotting, respectively. The effects of SKLB-03220, an EZH2 covalent inhibitor, on OC cell migration and invasion were investigated using wound-healing assays, Transwell assays, and immunohistochemistry. TCGA database analysis confirmed that the EZH2 and MMP9 mRNA expression was significantly higher in OC tissues, whereas TIMP2 expression was significantly lower than that in normal ovarian tissues. Moreover, EZH2 negatively correlated with TIMP2 and positively correlated with MMP9 expression. In addition to the anti-tumor activity of SKLB-03220 in a PA-1 xenograft model, immunohistochemistry results showed that SKLB-03220 markedly increased the expression of TIMP2 and decreased the expression of MMP9. Additionally, wound-healing and Transwell assays showed that SKLB-03220 significantly inhibited the migration and invasion of both A2780 and PA-1 cells in a concentration-dependent manner. SKLB-03220 inhibited H3K27me3 and MMP9 expression and increased TIMP2 expression in PA-1 cells. Taken together, these results indicate that the EZH2 covalent inhibitor SKLB-03220 inhibits metastasis of OC cells by upregulating TIMP2 and downregulating MMP9, and could thus serve as a therapeutic agent for OC.

Design, synthesis, and evaluation of VHL-based EZH2 degraders for breast cancer.

EZH2 (enhancer of zeste homolog 2) is one of the most important histone methyltransferases (HMTs), and overexpression of EZH2 can lead to proliferation, migration and angiogenesis of tumor cells. But most of EZH2 inhibitors are only effective against some hematologic malignancies and have poor efficacy against solid tumors. Here, we report the design, synthesis, and evaluation of highly potent proteolysis targeting chimeric (PROTACs) small molecules targeting EZH2. We developed a potent and effective EZH2 degrader P4, which effectively induced EZH2 protein degradation and inhibited breast cancer cell growth. Further studies showed that P4 can significantly decrease the degree of H3K27me3 in MDA-MB-231 cell line, induce apoptosis and G0/G1 phase arrest in Pfeiffer and MDA-MB-231 cell lines. Therefore, P4 is a potential anticancer molecule for breast cancer treatment.

Neuroprotective effects of GSK-343 in an in vivo model of MPTP-induced nigrostriatal degeneration.

Parkinson's disease (PD) is characterized by the degeneration of dopaminergic nigrostriatal neurons, which causes disabling motor disorders. Scientific findings support the role of epigenetics mechanism in the development and progression of many neurodegenerative diseases, including PD. In this field, some studies highlighted an upregulation of Enhancer of zeste homolog 2 (EZH2) in the brains of PD patients, indicating the possible pathogenic role of this methyltransferase in PD. The aim of this study was to evaluate the neuroprotective effects of GSK-343, an EZH2 inhibitor, in an in vivo model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic degeneration. Specifically, nigrostriatal degeneration was induced by MPTP intraperitoneal injection. GSK-343 was administered intraperitoneally daily at doses of 1 mg/kg, 5 mg/kg and 10 mg/kg, mice were killed 7 days after MPTP injection. Our results demonstrated that GSK-343 treatment significantly improved behavioral deficits and reduced the alteration of PD hallmarks. Furthermore, GSK-343 administration significantly attenuated the neuroinflammatory state through the modulation of canonical and non-canonical NF-κB/IκBα pathway as well as the cytokines expression and glia activation, also reducing the apoptosis process. In conclusion, the obtained results provide further evidence that epigenetic mechanisms play a pathogenic role in PD demonstrating that the inhibition of EZH2, mediated by GSK-343, could be considered a valuable pharmacological strategy for PD.

TGFß1-RCN3-TGFBR1 loop facilitates pulmonary fibrosis by orchestrating fibroblast activation.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) bears high mortality due to unclear pathogenesis and limited therapeutic options. Therefore, identifying novel regulators is required to develop alternative therapeutic strategies. METHODS: The lung fibroblasts from IPF patients and Reticulocalbin 3 (RCN3) fibroblast-selective knockdown mouse model were used to determine the importance of Rcn3 in IPF; the epigenetic analysis and protein interaction assays, including BioID, were used for mechanistic studies. RESULTS: Reticulocalbin 3 (RCN3) upregulation is associated with the fibrotic activation of lung fibroblasts from IPF patients and Rcn3 overexpression blunts the antifibrotic effects of pirfenidone and nintedanib. Moreover, repressing Rcn3 expression in mouse fibroblasts ameliorates bleomycin-induced lung fibrosis and pulmonary dysfunction in vivo. Mechanistically, RCN3 promotes fibroblast activation by maintaining persistent activation of TGFß1 signalling via the TGFß1-RCN3-TGFBR1 positive feedback loop, in which RCN3 upregulated by TGFß1 exposure detains EZH2 (an epigenetic methyltransferase) in the cytoplasm through RCN3-EZH2 interaction, leading to the release of the EZH2-H3K27me3 epigenetic repression of TGFBR1 and the persistent expression of TGFBR1. CONCLUSIONS: These findings introduce a novel regulating mechanism of TGFß1 signalling in fibroblasts and uncover a critical role of the RCN3-mediated loop in lung fibrosis. RCN3 upregulation may cause resistance to IPF treatment and targeting RCN3 could be a novel approach to ameliorate pulmonary fibrosis.

Inhibition of EZH2 suppresses peritoneal angiogenesis by targeting a VEGFR2/ERK1/2/HIF-1α-dependent signaling pathway.

The catalytic subunit of polycomb repressive complex 2 (PRC2), enhancer of zeste homolog 2 (EZH2), has been reported to be involved in angiogenesis in some tumors and autoimmune diseases. However, the mechanisms by which EZH2 regulates peritoneal angiogenesis remain unclear. We detected the expression of EZH2 in clinical samples and the peritoneal tissue of a mouse peritoneal fibrosis model induced by chlorhexidine gluconate (CG). In addition, we further investigated the mechanisms by which inhibition of EZH2 by 3-deazaneplanocin A (3-DZNeP) alleviated the CG-induced peritoneal fibrosis mouse model in vivo and 3-DZNeP or EZH2 siRNA treatment in cultured human peritoneal mesothelial cells (HPMCs) and human umbilical vein endothelial cells (HUVECs). The expression of EZH2 in the peritoneum of long-term peritoneal dialysis (PD) patients and the CG-induced peritoneal fibrosis mouse model was remarkably increased and this was positively associated with higher expression of vascular markers (CD31, CD34, VEGF, p-VEGFR2). Peritoneal injection of 3-DZNeP attenuated angiogenesis in the peritoneum of CG-injured mice; improved peritoneal membrane function; and decreased phosphorylation of STAT3, ERK1/2, and activation of Wnt1/ß-catenin. In in vitro experiments, we demonstrated that inhibition of EZH2 by 3-DZNeP or EZH2 siRNA decreased tube formation and the migratory ability of HUVECs via two pathways: the Wnt1/ß-catenin pathway and the IL-6/STAT3 pathway. Suppression of the Wnt1/ß-catenin pathway and the IL-6/STAT3 pathway subsequently reduced VEGF production in HPMCs. Using specific inhibitors of VEGFR2, ERK1/2, and HIF-1α, we found that a VEGFR2/ERK1/2/HIF-1α axis existed and contributed to angiogenesis in vitro. Moreover, phosphorylation of VEGFR2 and activation of the ERK1/2 pathway and HIF-1α in HUVECs could be suppressed by inhibition of EZH2. Taken together, the results of this study suggest that EZH2 may be a novel target for preventing peritoneal angiogenesis in PD patients. © 2022 The Pathological Society of Great Britain and Ireland.

Calcineurin/NFATc3 pathway mediates myocardial fibrosis in diabetes by impairing enhancer of zeste homolog 2 of cardiac fibroblasts.

BACKGROUND: Diabetes is associated with myocardial fibrosis, while the underlying mechanisms remain elusive. The aim of this study is to investigate the underlying role of calcineurin/nuclear factor of activated T cell 3 (CaN/NFATc3) pathway and the Enhancer of zeste homolog 2 (EZH2) in diabetes-related myocardial fibrosis. METHODS: Streptozotocin (STZ)-injected diabetic rats were randomized to two groups: the controlled glucose (Con) group and the diabetes mellitus (DM) group. Eight weeks later, transthoracic echocardiography was used for cardiac function evaluation, and myocardial fibrosis was visualized by Masson trichrome staining. The primary neonatal rat cardiac fibroblasts were cultured with high-glucose medium with or without cyclosporine A or GSK126. The expression of proteins involved in the pathway was examined by western blotting. The nuclear translocation of target proteins was assessed by immunofluorescence. RESULTS: The results indicated that high glucose treatment increased the expression of CaN, NFATc3, EZH2 and trimethylates lysine 27 on histone 3 (H3K27me3) in vitro and in vivo. The inhibition of the CaN/NFATc3 pathway alleviated myocardial fibrosis. Notably, inhibition of CaN can inhibit the nuclear translocation of NFATc3, and the expression of EZH2 and H3K27me3 protein induced by high glucose. Moreover, treatment with GSK126 also ameliorated myocardial fibrosis. CONCLUSION: Diabetes can possibly promote myocardial fibrosis by activating of CaN/NFATc3/EZH2 pathway.

Mesenchymal Stem Cell-Derived Exosome-Containing Linc00632 Regulates GATA Binding Protein-3 Expression in Allergic Rhinitis by Interacting with Enhancer of Zeste Homolog 2 to Inhibit T Helper Cell 2 Differentiation.

BACKGROUND: Allergic rhinitis (AR) is regarded as one of the most common allergic disease of nasal mucosa affecting many people worldwide. Long noncoding RNAs are critical modulators affecting AR progression, whereas the pathogenesis of Linc00632 in the development of AR remains unclear. METHODS: T helper cell 2 (Th2) differentiation of CD4+ T cells was measured by flow cytometry. Real-time quantitative PCR assay and Western blot were applied to determine the levels of RNA and proteins, respectively. The interleukin (IL)-4 and IL-13 levels were quantitatively assessed through ELISA. Subcellular fractionation was conducted to detect the cellular localization of Linc00632. RNA immunoprecipitation experiment was employed to validate the interaction relationship between Linc00632 and enhancer of zeste homolog 2 (EZH2). Chromatin immunoprecipitation assay was used for determination of protein-DNA interactions. RESULTS: The expression of Linc00632 was significantly decreased by 4 times in nasal mucosa of AR patients. Human umbilical cord mesenchymal stem cell-derived exosome dramatically inhibited Th2 differentiation, decreased GATA binding protein-3 (GATA-3) protein expressions and IL-4 levels by about 2 times in CD4+ T cells. Knockdown Linc00632 partially reversed the effects of exosomes on Th2 differentiation, IL-4 and IL-13 levels, and GATA-3 expression. Linc00632 overexpression could suppress Th2 differentiation of CD4+ T cells, reduced IL-4 and IL-13 levels, and GATA-3 expressions roughly 2 times. Linc00632 repressed the expression of GATA-3 by interacting with EZH2. GATA-3 overexpression partially reversed the effect of Linc00632 on Th2 differentiation of CD4+ T cells. CONCLUSION: Linc00632 acted as a suppression factor in Th2 differentiation by inhibiting the expression of GATA-3 via interacting with EZH2, which might provide a new insight for understanding the action mechanism of Linc00632 in AR.

Long non-coding RNA FOXP4-AS1 facilitates the biological functions of hepatocellular carcinoma cells via downregulating ZC3H12D by mediating H3K27me3 through recruitment of EZH2.

BACKGROUND: Some studies have reported the effect of long non-coding RNA forkhead box P4 antisense RNA 1 (lncRNA FOXP4-AS1) on hepatocellular carcinoma (HCC). Here, we aimed to discuss the effects of FOXP4-AS1/enhancer of zeste homolog 2 (EZH2)/trimethylation of lysine 27 on histone H3 (H3K27me3)/zinc finger CCCH-type containing 12D (ZC3H12D) axis on HCC. METHODS: The expression of FOXP4-AS1, EZH2, and ZC3H12D, and abundance of H3K27me3 in HCC tissues and cells were tested. The relationship between FOXP4-AS1 expression and prognosis of HCC patients was analyzed. The biological functions of HCC cells were detected via loss- and gain-of-function assays. The tumor weight and volume in vivo were tested. The interaction between FOXP4-AS1 and EZH2 as well as that between EZH2 and H3K27me3 was verified. RESULTS: FOXP4-AS1 and EZH2 expression and H3K27me3 abundance were enhanced while ZC3H12D expression was depressed in HCC tissues and cells. Knockdown of FOXP4-AS1 suppressed biological functions of HCC cells as well as the weight and volume of HCC transplanted tumor. Depleting ZC3H12D reversed the effect of downregulated FOXP4-AS1 on HCC cells. FOXP4-AS1 suppressed ZC3H12D expression via mediating H3K27me3 by recruitment of EZH2. CONCLUSION: The key findings of the present study demonstrate that FOXP4-AS1 suppresses ZC3H12D expression via mediating H3K27me3 by recruitment of EZH2, thus promoting the progression of HCC.

Elevated Expression of DNA Methyltransferases and Enhancer of Zeste Homolog 2 in Helicobacter pylori - Gastritis and Gastric Carcinoma.

AIM: The aim of this study was to study the role of key epigenetic regulators pertaining to DNA methylation and histone-modification systems in Helicobacter pylori (HP)-associated gastritis and gastric carcinogenesis. METHODS: The expression of DNA methyltransferase (DNMT-1, 3A, and 3B) and the catalytic subunit of polycomb repressive complex-2 (enhancer of zeste homolog 2 [EZH2]) in gastric carcinomas (n = 104), mucosa adjacent to carcinoma (n = 104), HP-associated gastritis (n = 95), and histologically normal mucosa (n = 31) was assessed by immunohistochemistry and qRT-PCR. RESULTS: The expression of all 3 DNMTs and EZH2 was significantly higher in HP-associated gastritis and carcinoma cases than in those with adjacent and normal mucosa. The expression of DNMT-1 and 3B was maximum in HP-associated gastritis. DNMT-3A showed higher expression in carcinoma-adjacent mucosa than in normal mucosa. Interestingly, the expression of EZH2 was higher in cases of HP-associated gastritis with metaplasia than in those without metaplasia and also in cases of intestinal type of adenocarcinoma. Significant positive correlation of EZH2 was identified with DNMT-1, DNMT-3A, and DNMT-3B. However, none of these markers was associated with survival outcome. CONCLUSION: This study establishes an important role of the key epigenetic regulators in the pathogenesis of both HP-associated gastritis and gastric carcinoma. Higher expression of all the epigenetic markers in the gastritis and their persistence in the carcinoma point toward their implications in HP-driven gastric carcinogenesis. Further, an inter-relation between the 2 arms of epigenetics, namely, DNA methylation and histone-modification in the pathogenesis of gastric carcinoma, is also documented. Given the reversibility of epigenetic phenomenon, these molecules may be of important therapeutic use.

LncRNA Dlx6os1 Accelerates Diabetic Nephropathy Progression by Epigenetically Repressing SOX6 via Recruiting EZH2.

INTRODUCTION: Diabetic nephropathy (DN) is the leading cause of kidney failure worldwide. To explore the pathogenesis and effective biological target of DN is beneficial to seeking novel treatment strategies. OBJECTIVE: This study aimed to investigate the role of the lncRNA Dlx6os1/SOX6/EZH2 axis in DN progression. METHODS: PAS staining was performed to evaluate extracellular matrix accumulation; ELISA was carried out to assess the levels of urine microalbumin and blood glucose concentration; RT-qPCR was carried out to detect the levels of lncRNA Dlx6os1, TNF-α, IL-1ß, IL-6, SOX6, and EZH2. Western blot was performed to assess the levels of Col-IV, FN, TGF-ß1, and SOX6 proteins. RIP assay was carried out to verify the interaction between lncRNA Dlx6os1 and EZH2. ChIP-qPCR was conducted to verify the interaction between EZH2 and SOX6 promoter. RESULTS: Our results illustrated that lncRNA Dlx6os1 was highly expressed in DN mice and HG-induced SV40 MES13 cells. LncRNA Dlx6os1 knockdown inhibited HG-induced SV40 MES13 cell proliferation, fibrosis, and inflammatory cytokine release. LncRNA Dlx6os1 inhibited SOX6 expression by recruiting EZH2 in HG-SV40 MES13 cells, and SOX6 mediated the effects of lncRNA Dlx6os1 on proliferation, fibrosis, and inflammatory factor release of HG-induced SV40 MES13 cells. CONCLUSION: LncRNA Dlx6os1 accelerates the progression of DN by epigenetically repressing SOX6 via recruiting EZH2.

Selective EZH2 inhibitor zld1039 alleviates inflammation in cisplatin-induced acute kidney injury partially by enhancing RKIP and suppressing NF-κB p65 pathway.

Enhancer of zeste homolog 2 (EZH2), a component of polycomb repressive complex 2 (PRC2), is a histone lysine methyltransferase mediating trimethylation of histone H3 at lysine 27 (H3K27me3), which is a repressive marker at the transcriptional level. EZH2 sustains normal renal function and its overexpression has bad properties. Inhibition of EZH2 overexpression exerts protective effect against acute kidney injury (AKI). A small-molecule compound zld1039 has been developed as an efficient and selective EZH2 inhibitor. In this study, we evaluated the efficacy of zld1039 in the treatment of cisplatin-induced AKI in mice. Before injection of cisplatin (20 mg/kg, i.p.), mice were administered zld1039 (100, 200 mg/kg, i.g.) once, then in the following 3 days. We found that cisplatin-treated mice displayed serious AKI symptoms, evidenced by kidney dysfunction and kidney histological injury, accompanied by EZH2 upregulation in the nucleus of renal tubular epithelial cells. Administration of zld1039 dose-dependently alleviated renal dysfunction as well as the histological injury, inflammation and cell apoptosis in cisplatin-treated mice. We revealed that zld1039 administration exerted an anti-inflammatory effect in kidney of cisplatin-treated mice via H3K27me3 inhibition, raf kinase inhibitor protein (RKIP) upregulation and NF-κB p65 repression. In the cisplatin-treated mouse renal tubular epithelial (TCMK-1) cells, silencing of RKIP with siRNA did not abolish the anti-inflammatory effect of EZH2 inhibition, suggesting that RKIP was partially involved in the anti-inflammatory effect of zld1039. Collectively, EZH2 inhibition alleviates inflammation in cisplatin-induced mouse AKI via upregulating RKIP and blocking NF-κB p65 signaling in cisplatin-induced AKI. The potent and selective EZH2 inhibitor zld1039 has the potential as a promising agent for the treatment of AKI.

LncRNA colorectal neoplasia differentially expressed promotes glycolysis of liver cancer cells by regulating hypoxia-inducible factor 1α.

LncRNAs are associated with tumorigenesis of liver cancer. LncRNA Colorectal Neoplasia Differentially Expressed (CRNDE) was identified as an oncogenic lncRNA and involved in tumor growth and metastasis. The role of CRNDE in liver cancer was investigated. CRNDE was elevated in liver cancer cells. Knockdown of CRNDE decreased cell viability and inhibited proliferation of liver cancer. Moreover, knockdown of CRNDE reduced levels of extracellular acidification rate, glucose consumption, and lactate production to repress glycolysis of liver cancer. Silence of CRNDE enhanced the expression of miR-142 and reduced enhancer of zeste homolog 2 (EZH2) and hypoxia-inducible factor 1α (HIF-1α). Over-expression of HIF-1α attenuated CRNDE silence-induced decrease of glucose consumption and lactate production. Injection with sh-CRNDE virus reduced in vivo tumor growth of liver cancer through up-regulation of miR-142 and down-regulation of EZH2 and HIF-1α. In conclusion, knockdown of CRNDE suppressed cell proliferation, glycolysis, and tumor growth of liver cancer through EZH2/miR-142/HIF-1α.

GSK343, an Inhibitor of Enhancer of Zeste Homolog 2, Reduces Glioblastoma Progression through Inflammatory Process Modulation: Focus on Canonical and Non-Canonical NF-κB/IκBα Pathways.

Glioblastoma (GB) is a tumor of the central nervous system characterized by high proliferation and invasiveness. The standard treatment for GB includes radiotherapy and chemotherapy; however, new therapies are needed. Particular attention was given to the role of histone methyltransferase enhancer of zeste-homolog-2 (EZH2) in GB. Recently, several EZH2-inhibitors have been developed, particularly GSK343 is well-known to regulate apoptosis and autophagy processes; however, its abilities to modulate canonical/non-canonical NF-κB/IκBα pathways or an immune response in GB have not yet been investigated. Therefore, this study investigated for the first time the effect of GSK343 on canonical/non-canonical NF-κB/IκBα pathways and the immune response, by an in vitro, in vivo and ex vivo model of GB. In vitro results demonstrated that GSK343 treatments 1, 10 and 25 µM significantly reduced GB cell viability, showing the modulation of canonical/non-canonical NF-κB/IκBα pathway activation. In vivo GSK343 reduced subcutaneous tumor mass, regulating canonical/non-canonical NF-κB/IκBα pathway activation and the levels of reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD). Ex vivo results confirmed the anti-proliferative effect of GSK343 and also demonstrated its ability to regulate immune response through CXCL9, CXCL10 and CXCL11 expression in GB. Thus, GSK343 could represent a therapeutic strategy to counteract GB progression, thanks to its ability to modulate canonical/non-canonical NF-κB/IκBα pathways and immune response.

Alpha Ketoglutarate Downregulates the Neutral Endopeptidase and Enhances the Growth Inhibitory Activity of Thiorphan in Highly Aggressive Osteosarcoma Cells.

Since natural substances are widely explored as epigenetic modulators of gene expression and epigenetic abnormalities are important causes of cancerogenesis, factors with pro-tumor activities subjected to epigenetic control, e.g., neutral endopeptidase (NEP, neprilysin), are promising anticancer targets for potential therapies acting via epigenetic regulation of gene expression. Alpha-ketoglutarate (AKG) is a naturally occurring co-substrate for enzymes involved in histone and DNA demethylation with suggested anti-cancer activity. Hence, we investigated a potential effect of AKG on the NEP expression in cells derived from various cancers (cervical, colon, osteosarcoma) and normal epithelial cells and osteoblasts. Moreover, the overall methylation status of histone H3 was explored to establish the molecular target of AKG activity. Additionally, it was investigated whether AKG in combination with thiorphan (NEP specific inhibitor) exhibited enhanced anticancer activity. The results revealed that AKG downregulated the expression of NEP at the protein level only in highly aggressive osteosarcoma HOS cells (flow cytometry and fluorometric assays), and this protease was found to be involved in AKG-induced growth inhibition in osteosarcoma cells (siRNA NEP silencing, BrdU assay, flow cytometry). Unexpectedly, AKG-induced hypermethylation of H3K27 in HOS cells, which was partially dependent on EZH2 activity. However, this effect was not implicated in the AKG-induced NEP downregulation (flow cytometry). Finally, the combined treatment with AKG and thiorphan was shown to significantly enhance the growth inhibitory potential of each one towards HOS cells (BrdU assay). These preliminary studies have shown for the first time that the downregulation of NEP expression is a promising target in therapies of NEP-implicating HOS cells. Moreover, this therapeutic goal can be achieved via AKG-induced downregulation of NEP and synergistic activity of AKG with thiorphan, i.e., a NEP specific inhibitor. Furthermore, this study has reported for the first time that exogenous AKG can influence the activity of histone methyltransferase, EZH2. However, this issue needs further investigation to elucidate the mechanisms of this phenomenon.

Phase 1 study of tazemetostat in Japanese patients with relapsed or refractory B-cell lymphoma.

BACKGROUND: Tazemetostat is a selective and orally available inhibitor of enhancer of zeste homolog 2 (EZH2), a histone methyltransferase and epigenetic regulator of cellular differentiation programs. We carried out a phase I study of tazemetostat in Japanese patients with relapsed or refractory B-cell non-Hodgkin-type lymphoma (B-NHL) to evaluate its tolerability, safety, pharmacokinetics, and preliminary antitumor activity. METHODS: Tazemetostat was given orally at a single dose of 800 mg on the first day and 800 mg twice daily (BID: total 1600 mg/d) on following days in a 28-day/cycle manner. Tazemetostat dose-limiting toxicity (DLT) was evaluated up to the end of the first treatment cycle. Archival tumor tissues were analyzed for hotspot EZH2 mutations. RESULTS: As of 15 January 2018, seven patients (four follicular lymphoma [FL] and three diffuse large B-cell lymphoma [DLBCL]) were enrolled. The median age was 73 (range, 59-85) years, and the median number of prior chemotherapy regimens was three (range, one to five). No DLT was observed (one patient was not evaluable due to early disease progression). The common treatment-related adverse events (AEs) were thrombocytopenia and dysgeusia (three patients each; 42.9%). No treatment-related serious AEs were observed. The objective response rate was 57% (4/7 patients), including responses in three of four patients with FL and one of three patients with DLBCL. An EZH2 mutation was detected in one patient with FL responding to treatment. CONCLUSIONS: Tazemetostat at 800 mg BID showed an acceptable safety profile and promising antitumor activity in Japanese patients with relapsed or refractory B-NHL.

Phase II study of tazemetostat for relapsed or refractory B-cell non-Hodgkin lymphoma with EZH2 mutation in Japan.

Tazemetostat is a selective, reversible, small-molecule inhibitor of the histone methyltransferase enzyme, enhancer of zest homolog 2 (EZH2). In this multicenter, open-label, phase II study, we assessed the efficacy and safety of tazemetostat in Japanese patients with relapsed or refractory (R/R) B-cell non-Hodgkin lymphoma harboring the EZH2 mutation. Tazemetostat (800 mg twice daily) was given orally (28-day cycle) until disease progression or unacceptable toxicity. Among the 20 eligible patients, 17 were enrolled in cohort 1 (follicular lymphoma [FL]), and three were enrolled in cohort 2 (diffuse large B-cell lymphoma). At data cut-off, the objective response rate in cohort 1 was 76.5%, including six patients (35.3%) with complete response and seven patients (41.2%) with partial response (PR). All three patients in cohort 2 achieved PR. In cohort 1, median progression-free survival (PFS) was not reached at the median follow-up of 12.9 months. The estimated PFS rate at 12 and 15 months was 94.1% and 73.2%, respectively. The most common grade 3 treatment-emergent adverse event (TEAE) was lymphopenia (n = 2). Grade 4 TEAEs included hypertriglyceridemia and pneumonia aspiration (n = 1 each), which were not related to tazemetostat. Treatment-emergent adverse events leading to study drug discontinuation were reported in four of the 20 patients, indicating that the safety profile of tazemetostat was acceptable and manageable. Tazemetostat 800 mg twice daily showed encouraging efficacy in patients with R/R EZH2 mutation-positive FL with a manageable safety profile in the overall population. Thus, tazemetostat could be a potential treatment for R/R EZH2 mutation-positive FL.

LINC00511-dependent inhibition of IL-24 contributes to the oncogenic role of HNF4α in colorectal cancer.

Hepatocyte nuclear factor 4 α (HNF4α) is an important transcription factor that acts as a pro-proliferative mediator during tumorigenesis, yet its function in colorectal cancer (CRC) remain unclear. Hence, this study aims to explore roles that HNF4α plays in the CRC development. RNA quantification analysis was conducted to characterize the expression pattern of long intergenic noncoding RNA 00511 (LINC00511)/HNF4α/IL-24 in CRC tissues and cell lines. Using gain- and loss-of-function approaches, effects of HNF4α/LINC00511/IL-24 axis on biological processes such as proliferative, migrating, invading, apoptotic, and tumorigenic functions of CRC cells were evaluated. We further identified the interactions among HNF4α/LINC00511/EZH2/IL-24 using RNA binding protein immunoprecipitation, RNA pull-down along with chromatin immunoprecipitation (ChIP). LINC00511 was an upregulated lncRNA in CRC tissues and cells, which played an oncogenic role by strengthening the malignant phenotypes of CRC cells. LINC00511 downregulated IL-24 expression by interacting with EZH2. HNF4α could enhance LINC00511 transcription in an epigenetic manner, which finally accelerated cancer progression and tumorigenesis through LINC00511-mediated inhibition of IL-24. Those data together demonstrated the contribution of HNF4α to the progression of CRC through mediating the LINC00511/EZH2/IL-24 axis. Hence, our study provides a promising therapeutic target for CRC.NEW & NOTEWORTHY Our findings on the roles of hepatocyte nuclear factor 4 α/long intergenic noncoding RNA 00511/IL-24 axis provide new insights into the CRC and offer potential targets for translational applications.

Emodin ameliorates tubulointerstitial fibrosis in obstructed kidneys by inhibiting EZH2.

Emodin, a major component of Chinese herbal rhubarb, delays the progression of chronic renal failure. However, the effect and working mechanisms of Emodin on renal tubulointerstitial fibrosis remains elusive. We hypothesized that emodin inhibits renal tubulointerstitial fibrosis through EZH2, a histone methyltransferase. Our in vivo and in vitro studies demonstrate that emodin reduced extracellular collagen deposition and inhibited Smad3 and CTGF pro-fibrotic signaling pathways, which were correlated with the down-regulation of EZH2 and reduced trimethylation of histone H3 on lysine 27 (H3k27me3) in NRK-49F fibrotic cells and UUO kidneys. Inhibition of EZH2 by 3-DZNeP blocked or attenuated the anti-fibrotic effect of emodin in UUO kidneys and NRK-49F cells. These data indicate that emodin inhibits renal tubulointerstitial fibrosis in obstructed kidneys and this effect is mediated through EZH2.

Long Noncoding RNA SPRY4-IT1 Modulates Ketamine-Induced Neurotoxicity in Human Embryonic Stem Cell-Derived Neurons through EZH2.

OBJECTIVE: This study aimed to investigate whether long noncoding RNA sprouty receptor tyrosine kinase signaling antagonist 4-intronic transcript 1 (SPRY4-IT1) is involved in the regulation of ketamine-induced neurotoxicity. METHODS: Human embryonic stem cells (hESCs) were induced into neurons in vitro and treated with ketamine. Apoptosis and neurite degeneration assays were used to determine ketamine-induced neurotoxicity and qRT-PCR to determine SPRY4-IT1 expression. SPRY4-IT1 was downregulated in hESC-induced neurons to examine its regulation on ketamine-induced neurotoxicity. The correlation between enhancer of zeste homolog 2 (EZH2) and SPRY4-IT1 was also examined. EZH2 was upregulated in SPRY4-IT1-downregualted hESC-induced neurons to further examine its participation in SPRY4-IT1-mediated ketamine neurotoxicity. RESULTS: Ketamine-induced dose-dependent apoptosis, neurite degeneration, and SPRY4-IT1 upregulation in hESC-induced neurons. Lentivirus-mediated SPRY4-IT1 downregulation protected ketamine neurotoxicity. EZH2 expression was positively correlated with SPRY4-IT1 in hESC-induced neurons. EZH2 overexpression markedly reversed the protective effects of SPRY4-IT1 knockdown on ketamine neurotoxicity. CONCLUSIONS: SPRY4-IT1 is involved in anesthesia-induced neurotoxicity, possibly through the regulation on EZH2 gene.