Paeoniflorin promotes PPARγ expression to suppress HSCs activation by inhibiting EZH2-mediated histone H3K27 trimethylation.

BACKGROUND: The alleviating effect of paeoniflorin (Pae) on liver fibrosis has been established; however, the molecular mechanism and specific target(s) underlying this effect remain elusive. PURPOSE: This study was to investigate the molecular mechanism underlying the regulatory effect of Pae on hepatic stellate cells (HSCs) activation in liver fibrosis, with a specific focus on the role of Pae in modulating histone methylation modifications. METHODS: The therapeutic effect of Pae was evaluated by establishing in vivo and in vitro models of carbon tetrachloride (CCl4)-induced mice and transforming growth factor ß1 (TGF-ß1)-induced LX-2 cells, respectively. Molecular docking, surface plasmon resonance (SPR), chromatin immunoprecipitation-quantitative real time PCR (ChIP-qPCR) and other molecular biological methods were used to clarify the molecular mechanism of Pae regulating HSCs activation. RESULTS: Our study found that Pae inhibited HSCs activation and histone trimethylation modification in liver of CCl4-induced mice and LX-2 cells. We demonstrated that the inhibitory effect of Pae on the activation of HSCs was dependent on peroxisome proliferator-activated receptor γ (PPARγ) expression and enhancer of zeste homolog 2 (EZH2). Mechanistically, Pae directly binded to EZH2 to effectively suppress its enzymatic activity. This attenuation leaded to the suppression of histone H3K27 trimethylation in the PPARγ promoter region, which induced upregulation of PPARγ expression. CONCLUSION: This investigative not only sheds new light on the precise targets that underlie the remission of hepatic fibrogenesis induced by Pae but also emphasizes the critical significance of EZH2-mediated H3K27 trimethylation in driving the pathogenesis of liver fibrosis.

Epigenetic regulation of enhancer of zeste homolog 2 (EZH2) -Yin Yang 1 (YY1) axis in cancer.

In accordance with the World Health Organization, cancer is the second leading cause of death in patients. In recent years, the number of cancer patients has been growing, and the occurrence of cancer in people is becoming more common, primarily due to lifestyle factors. Yin Yang 1 (YY1) is a transcription factor that is widespread throughout. It is a zinc finger protein, falling under the GLI-Kruppel class. YY1 is known to regulate transcriptional activation and repression of various genes associated with different cellular processes such as DNA repair, autophagy, cell survival and apoptosis, and cell division. Meanwhile, EZH2 is a histone-lysine N-methyltransferase enzyme encoded by gene 7 in humans. Its main function involves catalyzing the addition of methyl groups to histone H3 at lysine 27 (H3K27me3), and it is involved in regulating CD8 + T cell fate and function. It is a subunit of a Polycomb repressor complex 2 (PRC2). The EZH2 gene encodes for an enzyme that is involved in histone methylation and transcriptional repression. It adds methyl groups to lysine 27 on histone H3 (H3K27me3) with the help of the cofactor S-adenosyl-L-methionine. In addition to its role in epigenetic regulation, EZH2 also acts as a regulator of CD8+ T cell fate and function. EZH2 has been implicated in T Cell Receptor (TCR) signaling via the regulation of actin polymerization. In fact, EZH2 is involved in numerous signaling pathways that lead to tumorigenesis. EZH2 is mutated in cancer and shows overexpression. Due to its mutation and overexpression, the cells that help combat cancer are suppressed and carcinogenicity is promoted. The association of EZH2 and YY1 poses an intriguing mechanism in relation to cancer.

Depletion of enhancer zeste homolog 2 (EZH2) directs transcription factors associated with T cell differentiation through epigenetic regulation of Yin Yang 1(YY1) in combating non-small cell lung cancer (NSCLC).

Non-Small Cell Lung Cancer (NSCLC) is the leading cause of death in all countries alike. In the current study, we have found out that Histone H3Lys4trimethylation is abnormal on YY1 in CD4+T Helper (TH) cells of NSCLC patients which is evident by Histone H3Lys27 trimethylation mediated via EZH2. We investigated the status of Yin Yang 1 (YY1) and the involvement of certain transcription factors that lead to tumorigenesis after depleting endogenous EZH2 in vitro by CRISPR/Cas9 in the CD4+TH1-or-TH2-polarized cells isolated initially as CD4+TH0 cells from the PBMC of the control subjects and patients suffering from NSCLC. After depletion of endogenous EZH2, RT-qPCR based mRNA expression analysis showed that there was an increase in the expression of TH1 specific genes and a decrease in the expression of TH2 specific genes in NSCLC patients CD4+TH cells. We can conclude that this group of NSCLC patients may have the tendency at least in vitro to elucidate adaptive/protective immunity through the depletion of endogenous EZH2 along with the reduction in the expression of YY1. Moreover, depletion of EZH2 not only suppressed the CD4+CD25+FOXP3+Regulatory T cells (Treg) but also it aided the generation of CD8+Cytotoxic T Lymphocytes (CTL) which were involved in killing of the NSCLC cells. Thus the transcription factors involved in EZH2 mediated T cell differentiation linked to malignancies offers us an appealing avenue of targeted therapeutic intervention for NSCLC.

Capsaicin Reduces Cancer Stemness and Inhibits Metastasis by Downregulating SOX2 and EZH2 in Osteosarcoma.

Metastasis of osteosarcoma is an important adverse factor affecting patients' survival, and cancer stemness is the crucial cause of distant metastasis. Capsaicin, the main component of pepper, has been proven in our previous work to inhibit osteosarcoma proliferation and enhance its drug sensitivity to cisplatin at low concentrations. This study aims to further explore the anti-osteosarcoma effect of capsaicin at low concentrations (100[Formula: see text][Formula: see text]M, 24[Formula: see text]h) on stemness and metastasis. The stemness of human osteosarcoma (HOS) cells was decreased significantly by capsaicin treatment. Additionally, the capsaicin treatment's inhibition of cancer stem cells (CSCs) was dose-dependent on both sphere formation and sphere size. Meanwhile, capsaicin inhibited invasion and migration, which might be associated with 25 metastasis-related genes. SOX2 and EZH2 were the most two relevant stemness factors for capsaicin's dose-dependent inhibition of osteosarcoma. The mRNAsi score of HOS stemness inhibited by capsaicin was strongly correlated with most metastasis-related genes of osteosarcoma. Capsaicin downregulated six metastasis-promoting genes and up-regulated three metastasis-inhibiting genes, which significantly affected the overall survival and/or disease-free survival of patients. In addition, the CSC re-adhesion scratch assay demonstrated that capsaicin inhibited the migration ability of osteosarcoma by inhibiting its stemness. Overall, capsaicin exerts a significant inhibitory effect on the stemness expression and metastatic ability of osteosarcoma. Moreover, it can inhibit the migratory ability of osteosarcoma by suppressing its stemness via downregulating SOX2 and EZH2. Therefore, capsaicin is expected to be a potential drug against osteosarcoma metastasis due to its ability to inhibit cancer stemness.

Antagonizing EZH2 combined with vitamin D3 exerts a synergistic role in anti-fibrosis through bidirectional effects on hepatocytes and hepatic stellate cells.

BACKGROUND AND AIM: Whether vitamin D3 (VD3) supplementation is associated with improved liver fibrosis is controversial. METHODS: Liver fibrosis models were treated with VD3, active VD (1,25-OH2 Vitamin D3), or collaboration with GSK126 (Ezh2 inhibitor), respectively. Hepatic stellate cells (HSCs) were co-cultured with hepatocytes and then stimulated with TGF-ß. Autophagy of hepatocytes was determined after the intervention of 1,25-OH2 Vitamin D3 and GSK126. Also, the active status of HSCs and the mechanism with 1,25-OH2 Vitamin D3 and GSK126 intervention were detected. RESULTS: 1,25-OH2 Vitamin D3, but not VD3, is involved in anti-fibrosis and partially improves liver function, which might be associated with related enzymes and receptors (especially CYP2R1), leading to decreased of its biotransformation. GSK126 plays a synergistic role in anti-fibrosis. The co-culture system showed increased hepatocyte autophagy after HSCs activation. Supplementation with 1,25-OH2 Vitamin D3 or combined GSK126 reduced these effects. Further studies showed that 1,25-OH2 Vitamin D3 promoted H3K27 methylation of DKK1 promoter through VDR/Ezh2 due to the weakening for HSCs inhibitory signal. CONCLUSIONS: VD3 bioactive form 1,25-OH2 Vitamin D3 is responsible for the anti-fibrosis, which might have bidirectional effects on HSCs by regulating histone modification. The inhibitor of Ezh2 plays a synergistic role in this process.

Effects of EZH2 on Invasion and Migration of Endometrial Stromal Cells in Endometriosis Patients by Regulating PCDH10 Gene H3K27 Methylation.

Context: Endometriosis refers to the appearance of ectopic endometrioid tissue outside the uterus. Low PCDH10 expression has been associated with enhancer of zeste homolog 2 (EZH2), which catalyzes histone 3 (H3K27me3). H3K27me3 is an epigenetic marker associated with endometriosis. Objective: The study intended to explore the influence of protocadherin 10 (PCDH10) on the invasion and migration of endometrial stromal cells in endometriosis as well as its mechanism. Design: The research team designed a laboratory study using endometrial tissue. Setting: The study took place in Department of Obstetrics and Gynecology at South University of Science and Technology Hospital in Shenzhen, Guangdong Province, China. Participants: Participants were 10 patients with ovarian endometriosis (ovarian chocolate cysts) who were undergoing surgical treatment at the hospital between January and December 2019. The endometrial tissue of those participants became the endometriosis group. Other participants with normal endometrial tissue became the controls (n=10). Outcome Measures: The research team collected tissues from participants and used immunofluorescence, real-time quantitative polymerase chain reaction (qPCR), and Western blot assay to determine the expression levels of PCDH10, enhancer of zeste homolog 2 (EZH2), and histone H3 (H3K27me3). The team cultured endometrial stromal cells from participants primarily to detect the effects of silencing EZH2 on PCDH10 and H3K27me3 expression. The team used a Transwell assay and scratch test to examine the influence of silencing EZH2 on invasion and migration of endometrial stromal cells and applied chromatin immunoprecipitation to determine H3K27me3 enrichment in the PCDH10 gene promoter region. Results: PCDH10 in heterotopic endometrial tissues of endometriosis patients had low expression, while EZH2 and H3K27me3 were highly expressed. Silencing EZH2 inhibited EZH2 protein expression, increased PCDH10 expression, and inhibited invasion and migration of endometrial stromal cells by increasing PCDH10 expression. Silencing EZH2 also reduced H3K27me3 enrichment in PCDH10 promoter region. Conclusions: Low PCDH10 expression may be associated with high EZH2 expression and H3K27me3 enrichment in endometriosis patients, which promotes the migration and invasion of endometrial stromal cells. This connection provides a theoretical basis for the treatment of endometriosis.

Gambogenic acid alleviates kidney fibrosis via epigenetic inhibition of EZH2 to regulate Smad7-dependent mechanism.

BACKGROUND: Epigenetics regulating gene expression plays important role in kidney fibrosis. Natural products originating from diverse sources including plants and microorganisms are capable to influence epigenetic modifications. Gambogenic acid (GNA) is a caged xanthone extracted from gamboge resin, exudation of Garcinia hanburyi Hook.f., and the effect of GNA on kidney fibrosis with its underlying mechanism on epigenetics remains unknown. PURPOSE: This study aimed to explore the role of GNA against kidney fibrogenesis by histone methylation mediating gene expression. METHODS: Two experimental mice of unilateral ureteral obstruction (UUO) and folic acid (FA) were given two dosages of GNA (3 and 6 mg/kg/d). TGF-ß1 was used to stimulate mouse tubular epithelial (TCMK-1) cells and siRNAs were transfected to verify the underlying mechanisms of GNA. Histological changes were evaluated by HE, MASSON stainings, immunohistochemistry and immunofluorescence. Western blot and qPCR were used to measure protein/gene transcription levels. RESULTS: GNA dose-dependently alleviated UUO-induced kidney fibrosis and FA-induced kidney early fibrosis, indicated by the pathology and fibrotic factor changes (α-SMA, collagen I, collagen VI, and fibronectin). Mechanically, GNA reduced enhancer of zeste homolog 2 (EZH2) and H3K27me3, promoted Smad7 transcription, and inhibited TGF-ß/Smad3 fibrotic signaling in injured kidneys. Moreover, with TGF-ß1-induced EZH2 increasing, GNA suppressed α-SMA, fibronectin and collagen levels in tubular epithelial TCMK-1 cells. Although partially decreasing EZH2, GNA did not influence fibrotic signaling in Smad7 siRNA-transfected TCMK-1 cells. CONCLUSION: Epigenetic inhibition of EZH2 by GNA ameliorated kidney fibrogenesis via regulating Smad7-meidated TGF-ß/Smad3 signaling.

Morphoproteomics Identifies SIRT1, EZH2 and CXCR4 Pathways in Diffuse Large B-Cell Lymphoma: Therapeutic Implications.

OBJECTIVE: Diffuse large B-cell lymphoma (DLBCL) is the most aggressive form of non-Hodgkin's lymphoma. METHODS: We applied morphoproteomics to a tissue microarray of DLBCL cases to uncover commonalities in its biology with therapeutic implications. Morphoproteomic analysis of 9 individual cases of classic DLBCL included immunohistochemical probes to detect silent mating type information regulation 2 homolog 1 (SIRT1), enhancer of Zeste homolog 2 (EZH2) and C-X-C chemokine receptor 4 (CXCR4) and their cellular compartmentalization by bright field microscopy. RESULTS: We detected the expression of SIRT1 in the majority (>50%) of the tumoral nuclei of 8 of 9 cases of DLBCL and of EZH2 expression in the majority (>50%) of the tumoral nuclei in 9 of the 9 cases; and the expression of the tumoral stem cell marker, CXCR4 in the cytoplasmic and/or plasmalemmal compartment at >50% of the tumor cells in all 9 cases of DLBCL. The morphoproteomic findings of SIRT1 and EZH2 expression in DLBCL, for the most part, parallel the morphoproteomic findings in B-cell acute lymphoblastic leukemia. This concordance has pharmacogenomic and therapeutic implications. Similarly, the fact that EZH2 can enhance the expression of tumoral stem cell marker, CXCR4 implies that there is a block in differentiation in DLBCL. CONCLUSION: By targeting the Sirt1, EZH2 and CXCR4 pathways using relatively non-toxic adjuvant therapeutic agents such as metformin, melatonin, curcumin, sulforaphane, vitamin D3 and plerixafor, we should be able to target the biology of DLBCL.

Evaluation of an EZH2 inhibitor in patient-derived orthotopic xenograft models of pediatric brain tumors alone and in combination with chemo- and radiation therapies.

Brain tumors are the leading cause of cancer-related death in children. Tazemetostat is an FDA-approved enhancer of zeste homolog (EZH2) inhibitor. To determine its role in difficult-to-treat pediatric brain tumors, we examined EZH2 levels in a panel of 22 PDOX models and confirmed EZH2 mRNA over-expression in 9 GBM (34.6 ± 12.7-fold) and 11 medulloblastoma models (6.2 ± 1.7 in group 3, 6.0 ± 2.4 in group 4) accompanied by elevated H3K27me3 expression. Therapeutic efficacy was evaluated in 4 models (1 GBM, 2 medulloblastomas and 1 ATRT) via systematically administered tazemetostat (250 and 400 mg/kg, gavaged, twice daily) alone and in combination with cisplatin (5 mg/kg, i.p., twice) and/or radiation (2 Gy/day × 5 days). Compared with the untreated controls, tazemetostat significantly (Pcorrected < 0.05) prolonged survival times in IC-L1115ATRT (101% at 400 mg/kg) and IC-2305GBM (32% at 250 mg/kg, 45% at 400 mg/kg) in a dose-dependent manner. The addition of tazemetostat with radiation was evaluated in 3 models, with only one [IC-1078MB (group 4)] showing a substantial, though not statistically significant, prolongation in survival compared to radiation treatment alone. Combining tazemetostat (250 mg/kg) with cisplatin was not superior to cisplatin alone in any model. Analysis of in vivo drug resistance detected predominance of EZH2-negative cells in the remnant PDOX tumors accompanied by decreased H3K27me2 and H3K27me3 expressions. These data supported the use of tazemetostat in a subset of pediatric brain tumors and suggests that EZH2-negative tumor cells may have caused therapy resistance and should be prioritized for the search of new therapeutic targets.

Apigenin Induces Autophagy and Cell Death by Targeting EZH2 under Hypoxia Conditions in Gastric Cancer Cells.

Hypoxia is a major obstacle to gastric cancer (GC) therapy and leads to chemoresistance as GC cells are frequently exposed to the hypoxia environment. Apigenin, a flavonoid found in traditional medicine, fruits, and vegetables and an HDAC inhibitor, is a powerful anti-cancer agent against various cancer cell lines. However, detailed mechanisms involved in the treatment of GC using APG are not fully understood. In this study, we investigated the biological activity of and molecular mechanisms involved in APG-mediated treatment of GC under hypoxia. APG promoted autophagic cell death by increasing ATG5, LC3-II, and phosphorylation of AMPK and ULK1 and down-regulating p-mTOR and p62 in GC. Furthermore, our results show that APG induces autophagic cell death via the activation of the PERK signaling, indicating an endoplasmic reticulum (ER) stress response. The inhibition of ER stress suppressed APG-induced autophagy and conferred prolonged cell survival, indicating autophagic cell death. We further show that APG induces ER stress- and autophagy-related cell death through the inhibition of HIF-1α and Ezh2 under normoxia and hypoxia. Taken together, our findings indicate that APG activates autophagic cell death by inhibiting HIF-1α and Ezh2 under hypoxia conditions in GC cells.

Combination of curcumin with N-n-butyl haloperidol iodide inhibits hepatocellular carcinoma malignant proliferation by downregulating enhancer of zeste homolog 2 (EZH2) - lncRNA H19 to silence Wnt/ß-catenin signaling.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common cause of cancer-related death worldwide. Curcumin (C) has been extensively investigated in different types of malignancies, including hepatocellular carcinoma, but its physicochemical properties have significantly influenced its clinical use. Several approaches are being explored to enhance curcumin's therapeutic response, including its combination with various drugs. PURPOSE: This study aimed to evaluate the anti-tumor effect of curcumin (C) in combination with F2 (N-n-butyl haloperidol iodide) on hepatocellular carcinoma and its potential underlying mechanism in vitro and in vivo. METHODS: Cell proliferation was evaluated by CCK-8 and colony formation assays, and apoptosis was measured by flow cytometry. The migratory and invasive abilities of Hep3B and SMMC-7721 cells were measured by wound-healing and matrigel transwell assays. In order to investigate the molecular pathways, various experiments such as western blotting, qPCR, RNA-seq, immunostaining and transfection were performed. To evaluate the anti-HCC effects in vivo, a xenograft tumor model was used. RESULTS: Our findings showed that the combination of curcumin (C) & F2 (F2C) strongly inhibited malignant proliferation and migration in SMMC-7721 and Hep3B cells. The F2C treatment downregulates enhancer of zeste homolog 2 (EZH2) transcription and protein expression, which is key epigenetic regulator responsible for HCC development. Moreover, the inhibition of EZH2 by F2C led to Wnt/ß-catenin signaling inhibition by decreasing tri-methylation of histone H3 at lysine 27 (H3K27me3) and long non-coding RNA H19 expression. The inhibition of F2C was associated with the suppression of tumorigenicity in xenograft HCC models. CONCLUSION: These findings suggested that, F2C inhibited HCC formation, migration and its modulatory mechanism seemed to be associated with downregulation of EZH2, silencing Wnt/ß-catenin signaling by interacting with H19, suggesting that F2C may be a promising drug in the clinical treatment of HCC.

Scutellarein induces apoptosis and inhibits proliferation, migration, and invasion in ovarian cancer via inhibition of EZH2/FOXO1 signaling.

Scutellarein, a flavone found in the perennial herb Scutellaria baicalensis, has antitumorigenic activity in multiple human cancers. However, whether scutellarein can attenuate ovarian cancer (OC) is unclear. This study investigated the effects of scutellarein in OC. In vitro cell viability was assessed using MTT assay whereas proliferation was assessed using 5-ethynyl-2'-deoxyuridine and colony formation assays. Cell apoptosis was detected by an Annexin V-fluorescein isothiocyanate/propidium iodide assay. Wound-healing and Transwell assays were used to determine cell migration and invasion. The differential expression of enhancer of zeste homolog 2 (EZH2) and forkhead box protein O1 (FOXO1) was measured by Quantitative real-time PCR and western blot analysis. We found that scutellarein inhibited viability, migration, invasion of A2780 and SKOV-3 cells, and reduced the expression of EZH2 in OC cells. In addition, FOXO1 was downregulated in OC tissues and cells and negatively regulated by EZH2. Also, scutellarein inhibited tumor growth and metastasis in vivo. In conclusion, scutellarein alleviates OC by the regulation of EZH2/FOXO1 signaling.

Histone methylatic modification mediates the tumor-suppressive activity of curcumol in hepatocellular carcinoma via an Hotair/EZH2 regulatory axis.

ETHNOPHARMACOLOGICAL RELEVANCE: Curcuma kwangsiensis S. G. Lee & C. F. Liang (Guangxi ezhu, in Chinese) has been used as a traditional Chinese medicine (TCM) for approximately 2000 years. Curcumol is one of the major bioactive components of this herb, which has been demonstrated possesses anti-cancer properties, and was recorded in the Chinese Pharmacopoeia 2020 edition. However, most studies mainly focused on the superficial anti-cancer activity, the underlying mechanism remains poorly understood. AIM OF THE STUDY: In the present study, we aimed to investigate the anti-tumor effect of Curcumol on hepatocellular carcinoma (HCC), and elucidate its underlying mechanism from the perspective of epigenetic modification. MATERIALS AND METHODS: The potential anti-cancer properties of Curcumol were evaluated in HepG2 and SMMC-7721 cells. Its effects on cell growth, cell cycle, apoptosis and migration were examined in these HCC cells. Moreover, the lncRNA HOX transcript antisense intergenic RNA (Hotair) and histone methylatic modification were detected by qPCR and Western blotting assays. RESULTS: In the present study, Curcumol was illustrated to suppress cell growth in HCC cells via inducing apoptosis and cell cycle arrest. And it was also found that Curcumol inhibited the invasion and metastasis of HCC as well. As for the mechanism investigation, it was showed that lncRNA Hotair was significantly downregulated by Curcumol in HCC cells. As is well known, Hotair recruited histone methyltransferase enhancer of zeste homolog 2 (EZH2) to exert transcriptional regulation. Our results showed that EZH2 were downregulated by Curcumol in HCC cells, and thus disrupted the trimethylation of H3K9 and H3K27 which were specifically catalyzed by EZH2. CONCLUSIONS: In conclude, our results demonstrated that Curcumol suppressed tumor growth and metastasis via an Hotair/EZH2/histone modification regulatory axis.

Tanshinone I, a new EZH2 inhibitor restricts normal and malignant hematopoiesis through upregulation of MMP9 and ABCG2.

Rationale: Tanshinone, a type of diterpenes derived from salvia miltiorrhiza, is a particularly promising herbal medicine compound for the treatment of cancers including acute myeloid leukemia (AML). However, the therapeutic function and the underlying mechanism of Tanshinone in AML are not clear, and the toxic effect of Tanshinone limits its clinical application. Methods: Our work utilizes human leukemia cell lines, zebrafish transgenics and xenograft models to study the cellular and molecular mechanisms of how Tanshinone affects normal and abnormal hematopoiesis. WISH, Sudan Black and O-Dianisidine Staining were used to determine the expression of hematopoietic genes on zebrafish embryos. RNA-seq analysis showed that differential expression genes and enrichment gene signature with Tan I treatment. The surface plasmon resonance (SPR) method was used with a BIAcore T200 (GE Healthcare) to measure the binding affinities of Tan I. In vitro methyltransferase assay was performed to verify Tan I inhibits the histone enzymatic activity of the PRC2 complex. ChIP-qPCR assay was used to determine the H3K27me3 level of EZH2 target genes. Results: We found that Tanshinone I (Tan I), one of the Tanshinones, can inhibit the proliferation of human leukemia cells in vitro and in the xenograft zebrafish model, as well as the normal and malignant definitive hematopoiesis in zebrafish. Mechanistic studies illustrate that Tan I regulates normal and malignant hematopoiesis through direct binding to EZH2, a well-known histone H3K27 methyltransferase, and inhibiting PRC2 enzymatic activity. Furthermore, we identified MMP9 and ABCG2 as two possible downstream genes of Tan I's effects on EZH2. Conclusions: Together, this study confirmed that Tan I is a novel EZH2 inhibitor and suggested MMP9 and ABCG2 as two potential therapeutic targets for myeloid malignant diseases.

Genistein nanoformulation promotes selective apoptosis in oral squamous cell carcinoma through repression of 3PK-EZH2 signalling pathway.

BACKGROUND: Overexpression of polycomb protein contributes to epigenetic repression in oral squamous cell carcinoma (OSCC) ensuing in poor prognosis and aggressive phenotype. Several plant-based compounds could help prevent epigenome alteration and cancer progression, but their low bioavailability limits their therapeutic activity. HYPOTHESIS: In this study, we have synthesized genistein nanoformulation (GLNPs) and evaluated its epigenetic regulation mechanism for selective apoptosis induction in OSCC. METHODS: Lactalbumin was used to prepare nanoformulation of Genistein. The mechanism of epigenetic regulation and selective apoptosis by Genistein loaded nanoparticles was studied in OSCC cell line JHU011 and fibroblast cell line L929 using immunofluorescence, Western blotting and ChIP-qPCR assay. RESULTS: We have found that GLNPs treatment selectively induced apoptosis in OSCC compared to the normal fibroblast cells. This selective effect in OSCC is achieved through enhanced reactive oxygen species (ROS) generation followed by Bax mitochondrial translocation and caspase 3 activation. Further, GLNPs induced withdrawal of epigenetic transcription repression through concurrent downregulation of the polycomb group proteins (PcG) Bmi 1 and EZH2 along with their successive targets, UbH2AK119 and H3K27me3, which have immense therapeutic implications in the treatment of OSCC. Last, we have established that GLNPs regulate EZH2expression through proteasomal mediated degradation and 3PK inhibition; 3PK protein was found physically linked with EZH2 protein and its promoter region (-1107 to -1002). This event indicates that 3PK might play some crucial role in EZH2 expression and epigenetic control of OSCC. Moreover, the formulation showed improved biodistribution, aqueous dispersibility and enhanced biocompatibility In-vivo. CONCLUSIONS: These results provide evidence that GLNPs may withdraw epigenetic transcriptional repression and selectively induce apoptosis in human oral squamous cell carcinoma.

Triterpenoid saponins from Ilex cornuta protect H9c2 cardiomyocytes against H2O2-induced apoptosis by modulating Ezh2 phosphorylation.

ETHNOPHARMACOLOGICAL RELEVANCE: Ilex cornuta Lindl. et Paxt. (Aquifoliaceae family) belongs to the Ilex genus. The leaves of this plant are used for the popular herbal tea "Ku-Ding-Cha" in China due to their health benefits for sore throat, obesity and hypertension. Our previous studies have shown that the extract of Ilex cornuta root exerts cardioprotective effects in rat models of myocardial ischaemic injury, and several new kinds of triterpenoid saponins from Ilex cornuta (TSIC) have protective effects against hydrogen peroxide (H2O2)-induced cardiomyocyte injury. AIM OF THE STUDY: The aim of this study was to clarify the underlying mechanisms by which TSIC protect against H2O2-induced cardiomyocyte injury. MATERIALS AND METHODS: An H2O2-treated H9c2 cardiomyocyte line was used as an in vitro model of oxidation-damaged cardiomyocytes to evaluate the effects of TSIC. Apoptosis was detected with CCK-8 and annexin V assays and via analysis of the levels of apoptosis-associated proteins or genes. The underlying mechanisms related to Akt signalling, Ezh2 expression and activity, and ROS were clarified by Western blotting, quantitative PCR, flow cytometry and rescue experiments. RESULTS: TSIC protected H9c2 cells from H2O2-induced apoptosis. This effect of TSIC was attributable to inhibition of Ezh2 activity, as exhibited by attenuation of H2O2-induced Akt signalling-dependent phosphorylation of Ezh2 at serine 21 (pEzh2S21) upon TSIC pretreatment. In addition, feedback pathway between Akt-dependent Ezh2 phosphorylation and ROS was involved in TSIC-mediated protection of H9c2 cells from apoptosis. CONCLUSIONS: Our findings indicate a pivotal role of the pEzh2S21 network in TSIC-mediated protection against cardiomyocyte apoptosis, potentially providing evidence of the mechanism of TSIC in the treatment and prevention of cardiovascular diseases.

Long noncoding RNA LINC01578 drives colon cancer metastasis through a positive feedback loop with the NF-κB/YY1 axis.

Metastasis accounts for poor prognosis of cancers and related deaths. Accumulating evidence has shown that long noncoding RNAs (lncRNAs) play critical roles in several types of cancer. However, which lncRNAs contribute to metastasis of colon cancer is still largely unknown. In this study, we found that lncRNA LINC01578 was correlated with metastasis and poor prognosis of colon cancer. LINC01578 was upregulated in colon cancer, associated with metastasis, advanced clinical stages, poor overall survival, disease-specific survival, and disease-free survival. Gain-of-function and loss-of-function assays revealed that LINC01578 enhanced colon cancer cell viability and mobility in vitro and colon cancer liver metastasis in vivo. Mechanistically, nuclear factor kappa B (NF-κB) and Yin Yang 1 (YY1) directly bound to the LINC01578 promoter, enhanced its activity, and activated LINC01578 expression. LINC01578 was shown to be a chromatin-bound lncRNA, which directly bound NFKBIB promoter. Furthermore, LINC01578 interacted with and recruited EZH2 to NFKBIB promoter and further repressed NFKBIB expression, thereby activating NF-κB signaling. Through activation of NF-κB, LINC01578 further upregulated YY1 expression. Through activation of the NF-κB/YY1 axis, LINC01578 in turn enhanced its own promoter activity, suggesting that LINC01578 and NF-κB/YY1 formed a positive feedback loop. Blocking NF-κB signaling abolished the oncogenic roles of LINC01578 in colon cancer. Furthermore, the expression levels of LINC01578, NFKBIB, and YY1 were correlated in clinical tissues. Collectively, this study demonstrated that LINC01578 promoted colon cancer metastasis via forming a positive feedback loop with NF-κB/YY1 and suggested that LINC01578 represents a potential prognostic biomarker and therapeutic target for colon cancer metastasis.

YAP-Mediated Recruitment of YY1 and EZH2 Represses Transcription of Key Cell-Cycle Regulators.

The Hippo pathway regulates cell proliferation and organ size through control of the transcriptional regulators YAP (yes-associated protein) and TAZ. Upon extracellular stimuli such as cell-cell contact, the pathway negatively regulates YAP through cytoplasmic sequestration. Under conditions of low cell density, YAP is nuclear and associates with enhancer regions and gene promoters. YAP is mainly described as a transcriptional activator of genes involved in cell proliferation and survival. Using a genome-wide approach, we show here that, in addition to its known function as a transcriptional activator, YAP functions as a transcriptional repressor by interacting with the multifunctional transcription factor Yin Yang 1 (YY1) and Polycomb repressive complex member enhancer of zeste homologue 2 (EZH2). YAP colocalized with YY1 and EZH2 on the genome to transcriptionally repress a broad network of genes mediating a host of cellular functions, including repression of the cell-cycle kinase inhibitor p27, whose role is to functionally promote contact inhibition. This work unveils a broad and underappreciated aspect of YAP nuclear function as a transcriptional repressor and highlights how loss of contact inhibition in cancer is mediated in part through YAP repressive function. SIGNIFICANCE: This study provides new insights into YAP as a broad transcriptional repressor of key regulators of the cell cycle, in turn influencing contact inhibition and tumorigenesis.

EZH2-mediated H3K27me3 inhibits ACE2 expression.

The outbreak of corona virus disease 2019 (COVID-19) caused by SARS-CoV-2 infection is spreading globally and quickly, leading to emerging health issues. SARS-CoV-2 enters into and infects host cells through its spike glycoprotein recognizing the cell receptor Angiotensin-converting enzyme II (ACE2). Here, we noticed that ACE2 was further enhanced by SARS-CoV-2 infection. Human germ cells and early embryos express high level of ACE2. Notably, RNA-seq result showed that reduction of H3K27me3, but not H3K4/9/36me3, led to upregulation of Ace2 expression in mouse germ cell line GC-2. In agreement with this result, we found in human embryonic stem cells that ACE2 expression was significantly increased in absence of EZH2, the major enzyme catalyzing H3K27me3. ChIP-seq analysis further confirmed decrease of H3K27me3 signal and increase of H3K27ac signal at ACE2 promoter upon EZH2 knockout. Therefore, we propose that EZH2-mediated H3K27me3 at ACE2 promoter region inhibits ACE2 expression in mammalian cells. This regulatory pattern may also exist in other human cells and tissues. Our discovery provides clues for pathogenesis and targeted drug therapy towards ACE2 expression for prevention and adjuvant therapy of COVID-19.

1,25-Dihydroxyvitamin D protects against age-related osteoporosis by a novel VDR-Ezh2-p16 signal axis.

To determine whether 1,25-dihydroxyvitamin D (1,25(OH)2 D) can exert an anti-osteoporosis role through anti-aging mechanisms, we analyzed the bone phenotype of mice with 1,25(OH)2 D deficiency due to deletion of the enzyme, 25-hydroxyvitamin D 1α-hydroxylase, while on a rescue diet. 1,25(OH)2 D deficiency accelerated age-related bone loss by activating the p16/p19 senescence signaling pathway, inhibiting osteoblastic bone formation, and stimulating osteoclastic bone resorption, osteocyte senescence, and senescence-associated secretory phenotype (SASP). Supplementation of exogenous 1,25(OH)2 D3 corrected the osteoporotic phenotype caused by 1,25(OH)2 D deficiency or natural aging by inhibiting the p16/p19 pathway. The proliferation, osteogenic differentiation, and ectopic bone formation of bone marrow mesenchymal stem cells derived from mice with genetically induced deficiency of the vitamin D receptor (VDR) were significantly reduced by mechanisms including increased oxidative stress, DNA damage, and cellular senescence. We also demonstrated that p16 deletion largely rescued the osteoporotic phenotype caused by 1,25(OH)2 D3 deficiency, whereas 1,25(OH)2 D3 could up-regulate the enzyme Ezh2 via VDR-mediated transcription thereby enriching H3K27me3 and repressing p16/p19 transcription. Finally, we demonstrated that treatment with 1,25(OH)2 D3 improved the osteogenic defects of human BM-MSCs caused by repeated passages by stimulating their proliferation and inhibiting their senescence via the VDR-Ezh2-p16 axis. The results of this study therefore indicate that 1,25(OH)2 D3 plays a role in preventing age-related osteoporosis by up-regulating Ezh2 via VDR-mediated transcription, increasing H3K27me3 and repressing p16 transcription, thus promoting the proliferation and osteogenesis of BM-MSCs and inhibiting their senescence, while also stimulating osteoblastic bone formation, and inhibiting osteocyte senescence, SASP, and osteoclastic bone resorption.