Epigenetic drug library screening reveals targeting DOT1L abrogates NAD+synthesis by reprogramming H3K79 methylation in uveal melanoma / 药物分析学报

Uveal melanoma(UM)is the most frequent and life-threatening ocular malignancy in adults.Aberrant histone methylation contributes to the abnormal transcriptome during oncogenesis.However,a comprehensive understanding of histone methylation patterns and their therapeutic potential in UM remains enigmatic.Herein,using a systematic epi-drug screening and a high-throughput transcriptome profiling of histone methylation modifiers,we observed that disruptor of telomeric silencing-1-like(DOT1L),a methyltransferase of histone H3 lysine 79(H3K79),was activated in UM,especially in the high-risk group.Concordantly,a systematic epi-drug library screening revealed that DOT1 L inhibitors exhibited salient tumor-selective inhibitory effects on UM cells,both in vitro and in vivo.Combining Cleavage Under Targets and Tagmentation(CUT&Tag),RNA sequencing(RNA-seq),and bioinformatics analysis,we identified that DOT1 L facilitated H3K79 methylation of nicotinate phosphoribosyltransferase(NAPRT)and epigenetically activated its expression.Importantly,NAPRT served as an oncogenic accel-erator by enhancing nicotinamide adenine dinucleotide(NAD+)synthesis.Therapeutically,DOT1L inhi-bition epigenetically silenced NAPRT expression through the diminishment of dimethylation of H3K79(H3K79me2)in the NAPRT promoter,thereby inhibiting the malignant behaviors of UM.Conclusively,our findings delineated an integrated picture of the histone methylation landscape in UM and unveiled a novel DOT1L/NAPRT oncogenic mechanism that bridges transcriptional addiction and metabolic reprogramming.

Hedgehog pathway orchestrates the interplay of histone modifications and tailors combination epigenetic therapies in breast cancer

Epigenetic therapies that cause genome-wide epigenetic alterations, could trigger local interplay between different histone marks, leading to a switch of transcriptional outcome and therapeutic responses of epigenetic treatment. However, in human cancers with diverse oncogenic activation, how oncogenic pathways cooperate with epigenetic modifiers to regulate the histone mark interplay is poorly understood. We herein discover that the hedgehog (Hh) pathway reprograms the histone methylation landscape in breast cancer, especially in triple-negative breast cancer (TNBC). This facilitates the histone acetylation caused by histone deacetylase (HDAC) inhibitors and gives rise to new therapeutic vulnerability of combination therapies. Specifically, overexpression of zinc finger protein of the cerebellum 1 (ZIC1) in breast cancer promotes Hh activation, facilitating the switch of H3K27 methylation (H3K27me) to acetylation (H3K27ac). The mutually exclusive relationship of H3K27me and H3K27ac allows their functional interplay at oncogenic gene locus and switches therapeutic outcomes. Using multiple in vivo breast cancer models including patient-derived TNBC xenograft, we show that Hh signaling-orchestrated H3K27me and H3K27ac interplay tailors combination epigenetic drugs in treating breast cancer. Together, this study reveals the new role of Hh signaling-regulated histone modifications interplay in responding to HDAC inhibitors and suggests new epigenetically-targeted therapeutic solutions for treating TNBC.

The engagement of histone lysine methyltransferases with nucleosomes: structural basis, regulatory mechanisms, and therapeutic implications

Histone lysine methyltransferases (HKMTs) deposit methyl groups onto lysine residues on histones and play important roles in regulating chromatin structure and gene expression. The structures and functions of HKMTs have been extensively investigated in recent decades, significantly advancing our understanding of the dynamic regulation of histone methylation. Here, we review the recent progress in structural studies of representative HKMTs in complex with nucleosomes (H3K4, H3K27, H3K36, H3K79, and H4K20 methyltransferases), with emphasis on the molecular mechanisms of nucleosome recognition and trans-histone crosstalk by these HKMTs. These structural studies inform HKMTs' roles in tumorigenesis and provide the foundations for developing new therapeutic approaches targeting HKMTs in cancers.

SET8 Inhibition Potentiates Radiotherapy by Suppressing DNA Damage Repair in Carcinomas / 生物医学与环境科学（英文）

Objective@#SET8 is a member of the SET domain-containing family and the only known lysine methyltransferase (KMT) that monomethylates lysine 20 of histone H4 (H4K20me1). SET8 has been implicated in many essential cellular processes, including cell cycle regulation, DNA replication, DNA damage response, and carcinogenesis. There is no conclusive evidence, however, regarding the effect of SET8 on radiotherapy. In the current study we determined the efficacy of SET8 inhibition on radiotherapy of tumors and the underlying mechanism.@*Methods@#First, we explored the radiotherapy benefit of the SET8 expression signature by analyzing clinical data. Then, we measured a series of biological endpoints, including the xenograft tumor growth in mice and apoptosis, frequency of micronuclei, and foci of 53BP1 and γ-H2AX in cells to detect the SET8 effects on radiosensitivity. RNA sequencing and subsequent experiments were exploited to verify the mechanism underlying the SET8 effects on radiotherapy.@*Results@#Low expression of SET8 predicted a better benefit to radiotherapy in lung adenocarcinoma (LUAD) and invasive breast carcinoma (BRCA) patients. Furthermore, genetic deletion of SET8 significantly enhanced radiation treatment efficacy in a murine tumor model, and A549 and MCF7 cells; SET8 overexpression decreased the radiosensitivity. SET8 inhibition induced more apoptosis, the frequency of micronuclei, and blocked the kinetics process of DNA damage repair as 53BP1 and γ-H2AX foci remained in cells. Moreover, RNF8 was positively correlated with the SET8 impact on DNA damage repair.@*Conclusion@#Our results demonstrated that SET8 inhibition enhanced radiosensitivity by suppressing DNA damage repair, thus suggesting that SET8 potentiated radiotherapy of carcinomas. As new inhibitors of SET8 are synthesized and tested in preclinical and clinical settings, combining SET8 inhibitors with radiation warrants consideration for precise radiotherapy.

Effect of histone methylation and its inhibitors on the progression of colorectal cancer / 国际生物医学工程杂志

Colorectal cancer is a malignant tumor occurring in the colon or rectum, which has a high incidence rate. In order to improve the prognosis of colorectal cancer, the pathogenesis of colorectal cancer still needs to be further clarified. Epigenetics can directly affect the progression and metastasis of colorectal cancer, and histone methylation is an important means of histone modification, which can regulate the transcriptional activation and inhibition of downstream genes. A large number of studies have confirmed the effects of histone methylation on the progression of colorectal cancer, and inhibitors of related methylation and demethylation may play a role as potential therapeutic drugs for colorectal cancer. In this article, the colorectal cancer and its related methylation regulation were introduced, the types of histone methylation modifications and their regulation were summarized, and the regulation of histone methyltransferases and demethylases involved in the progression of colorectal cancer was demonstrated. In addition, the potential significance of histone methylation inhibitors for the treatment of colorectal cancer was summarized, and the possibility of related inhibitors as treatment drugs for colorectal cancer was explored.

Perspectivas moleculares en cardiopatía hipertrófica: abordaje epigenético desde la modificación de la cromatina / Molecular perspectives in hypertrophic cardiomyopathy: epigenetic approach from chromatin remodeling

Resumen Los cambios epigenéticos inducidos por factores ambientales tienen cada día más relevancia en las enfermedades cardiovasculares. Uno de los componentes moleculares más observados en la hipertrofia cardiaca es la reactivación de los genes fetales causados por diversas patologías que incluyen obesidad, hipertensión arterial, estenosis valvular aórtica, causas congénitas, entre otras. A pesar de las múltiples investigaciones cuyo objetivo es obtener información acerca de los componentes moleculares de esta patología, su influencia en las estrategias terapéuticas es relativamente escasa. En la actualidad se busca información acerca de las proteínas que modifican la expresión de los genes fetales que se reactivan en esta condición. La relación entre las histonas y el ADN tiene un control reconocido en la expresión de genes que son condicionados por el ambiente e inducen modificaciones epigenéticas. Las deacetilasas de histonas son un grupo de proteínas que han demostrado tener un papel importante en la diferenciación de la célula cardiaca y además pueden ser claros componentes en el desarrollo de la hipertrofia cardiaca. En este trabajo se revisan los conocimientos actuales sobre la influencia de estas proteínas y los posibles planes terapéuticos en la hipertrofia cardiaca.

Abstract Epigenetic alterations induced by environmental factors are more relevant each day for cardiovascular diseases. One of the most observed molecular components in hypertrophic cardiomyopathy is the reactivation of fetal genes caused by multiple conditions, including obesity, high blood pressure, aortic valve stenosis and congenital causes. Despite several investigations with the objective of obtaining information regarding molecular components of this condition, its influence in therapeutic strategies is relatively scarce. Nowadays information is being searched about proteins that modify the expression of the fetal genes that reactivate with this condition. The relationship between histones and DNA has a recognised control in the expression of genes that are subject to the environment and induce epigenetic alterations. Histone deacetylases are a group of proteins that have revealed to play an important role in differentiation the cardiac cell and could be clear components in the development of hypertrophic cardiomyopathy. In this study current knowledge about the influence of these proteins and possible therapeutic plans for hypertrophic cardiomyopathy are revised.

Effects of pargyline on histone methylation in promoter and enhancer regions and transcription of CYP3A4/3A7 / 药学学报

This study was designed to investigate effects of pargyline on histone methylation in the promoter and enhancer regions and transcription of cytochrome P450 3A4/3A7 (CYP3A4/3A7) gene. Human primary fetal liver cells were isolated, cultured and randomly divided into several groups including control, solvent, pargyline low, middle, high dose (treated with 0.6, 1.2, 2.4 mmol·L-1). HepG2 cells were cultured and treated with 0.03, 0.3, 3 mmol·L-1 pargyline. After 48 hours, total RNAs were prepared from the cells to determine the expression of CYP3A mRNA in primary fetal cells and HepG2 cells with real-time quantative PCR (qPCR). HepG2 cells were cultured and then treated with 3 mmol·L-1 pargyline for 48 hours. The chromatin immunoprecipitation (ChIP) assay was performed with dimethylation of histone H3 at lysine 4 (H3K4me2), and IgG antibodies respectively. The precipitated DNA was resuspended and used for qPCR. Primers were used to detect different regions of CYP3A4/3A7 promoter and enhancer. Occupancy of H3K4me2 was shown as percent of input DNA relative to control cells. The results suggested that pargyline has an effect on primary fetal liver cells and HepG2 cells proliferation. The level of CYP3A7 was markedly enhanced in human primary fetal liver cells by treatment with 1.2, 2.4 mmol·L-1 of pargyline (P-1 of pargyline in HepG2 cells (P<0.001) compared with solvent control. Occupancy of H3K4me2 on human CYP3A4 promoter (-362 to +53) and enhancer segment (-7 836 to -6 093) harbored the overlapping hepatocyte nuclear factors 4A (HNF4A) binding site compared with a negative control. Occupancy of H3K4me2 on human CYP3A7 promoter (-163 to +103) and enhancer segment (-4 054 to -3 421, -6 265 to -6 247) overlapped with glucocorticoid receptor (GR) binding site. In conclusion, the enriched H3K4me2 in the promoter and enhancer regions was induced by pargyline with HNF4A or GR binding site in CYP3A4/3A7 gene to activate the corresponding genes.

Epigenetic modifications in mental disordersZhang / 中华行为医学与脑科学杂志

Mental disorders are caused by the synergy of genetic and environmental factors,and epigenetics provides a bridge for mental disorders between environmental exposure and genetic background.This review discussed the role of epigenetics on the development of mental disorders,especially in schizophrenia and depression.DNA methylation,histone acetylation,histone methylation,ncRNA,depressive disorder and schizophrenia were used as searching terms.('Schizophrenia OR depressive disorder') and all field of DNA methylation/histone acetylation/histone methylation/ncRNA were taken as index strategy.67 related articles in database of PubMed,ScienceDirect in March 2017 were acquired.41 articles were enrolled as reviewing materials according to literature screening.Existing researches suggest that epigenetic modifications,including DNA methylation,histone acetylation,histone methylation,and ncRNAs,may be associated with the occurrence of mental illnesses and play key roles in the pathogenesis of mental illnesses,especially in schizophrenia and depression.Further studies on them could provide us novel insights into the pathogenesis of these disorders and effective treatments based upon epigenetic mechanisms.

Expression Difference and Its Mechanisms of miR-497 and miR-34a in Platinum-sensitive and Platinum-re-sistant Epithelial Ovarian Carcinoma Patients / 中国药房

OBJECTIVE:To investigate the expression difference and its mechanism of miR-497 and miR-34a in platinum-sen-sitive and platinum-resistant epithelial ovarian carcinoma(EOC)patients. METHODS:A total of 72 EOC patients underwent ovari-an cancer staging surgery or cytoreductive surgery were selected from department of gynaecology and obstetriscs of our hospital dur-ing Jan. 2008-Jan. 2012. They received standardized platinum chemotherapy after surgery and were followed up (during Jul.2008-Jul.2016). According to the sensitivity to platinum,those patients were divided into platinum-sensitive group (42 cases) and platinum-resistant group (30 cases) . Real-time fluorescent quantitative PCR was adopted to detect the expression of miR-497 and miR-34a in tumor tissue,and the relationship of it with total survival period was investigated. The levels of DNA methylation of miR-497 and miR-34a promoter region were determined by nest type land type methylation specific PCR. Western blot assay was used to detect the H3K9 dimethylation(H3K9me2)levels. The H3K9me2 levels of miR-497 and miR-34a promoter region were de-termined by chromatin immunoprecipitation method. RESULTS:The expression levels of miR-497 and miR-34a in platinum-sensi-tive group were significantly higher than platinum-resistant group,with statistical significance (P0.05). CONCLUSIONS:The expression of miR-497 and miR-34a in tumor tissue of EOC patients are related to the sensitivity of platinum chemotherapy and the survival time of patients. DNA methylation and histone methylation of promoter region may be one of the mechanisms of their expression changes.

Ontogeny of drug metabolism enzymes and epigentic regulation / 中国药理学通报

Great changes in drug metabolizing enzyme (DME) expression occur in the fetus and child during development. Individual hepatic DME ontogeny can be categorized into one of three groups based on developmental trajectories.Some enzymes such as CYP3A7,are expressed at highest level in the fetus dur-ing the first trimester and either remain elevated or slightly de-crease during gestation,but are silenced or reduced to relatively low levels within one to two years after birth.SULT1 A1 is an ex-ample of the second group of DME.These enzymes are ex-pressed at relatively constant levels throughout gestation and into adulthood.CYP3A4 belongs to the third DME group .These en-zymes are expressed at negligible or low levels in the fetus.Sig-nificant increases in enzyme levels are exhibited within the first one to two years after birth.The epigenetic regulation refers to genomic modifications that do not involve changes in DNA se-quence and include DNA methylation,histone modifications, and non-coding RNAs.The epigenetic regulation mechanisms are responsible for the developmental expression of DME genes dur-ing liver maturation.This review will provide a summary of DME developmental expression profiles and reveal epigenetic mecha-nisms underlying variable drug metabolism and drug response. Thus,knowledge regarding DME ontogeny has permitted im-proved capability to predict drug disposition in pediatric pa-tients,which is crucial for improving drug dosing leading to opti-mal safety and efficacy in children.

Changes and significances of IL-17-associated histone methylation in the acute phase of Kawasaki dis-ease / 中华微生物学和免疫学杂志

Objective To investigate the changes and significances of IL-17-associated histone methylation in the acute phase of Kawasaki disease (KD). Methods Forty-two children with KD and 28 age-matched healthy children were recruited in this study. Co-immunoprecipitation and real-time PCR were performed to detect the IL-17-associated histone methylation in CD4+ T cells. The percentages of CD4+IL-17+ T cells (Th17) and the expression of IL-17 and pSTAT3 at protein level were analyzed by flow cytome-try. Quantitative real-time PCR was used to measure the expression of IL-17, IL-6Rα, gp130, IL-23R, IL-23Rβ1, ETV5, SOCS1, SOCS3, TLR4, MyD88/TRIF, TNFR1 and RIP1 at mRNA level and the expres-sion of miR155 in CD4+ T cells. The levels of IL-6, IL-23 and TNF-αin plasma samples were measured by enzyme-linked immunosorbent assay. Results (1) The children with acute KD showed increased percenta-ges of Th17 cells and enhanced expression of IL-17 and H3K4me3, but inhibited expression of H3K27me3 [H3K4me3:(3.79±1. 45)% vs (1. 93±0. 31)%, H3K27me3: (54. 51±13. 60)% vs (73. 96± 22. 32)%;P<0. 05]. Moreover, the three former indexes in KD patients complicated with coronary artery lesions ( KD-CAL+) were higher than those in KD patients without coronary artery lesions ( KD-CAL-) , while the levels of H3K27me3 in KD-CAL+ group were lower than those in KD-CAL- group [ H3K4me3:(5. 11±1. 68)% vs (2. 98±0. 99)%, H3K27me3:(45. 02±14. 83)% vs (60. 35±12. 51)%;P<0. 05]. A positive correlation was observed between the ratio of H3K4me3/H3K27me3 and IL-17 at transcriptional level in patients with acute KD (r=0. 69, P<0. 05). Treatment with intravenous immunoglobulin (IVIG) restored Th17 cells, expression of IL-17 and methylation levels of H3K4me3 and H3K27me3 to normal levels [H3K4me3:(2. 44 ± 0. 77)% vs (3. 79 ± 1. 45)%, H3K27me3: (66. 52 ± 15. 73)% vs (54. 51 ± 13. 60)%;P<0. 05]. (2) The expressions of pSTAT3, ETV5 and miR155 increased significantly in pa-tients with acute KD, while the expressions of negative regulators of pSTAT3 ( SOCS1 and SOCS3 ) were down-regulated. The expressions of pSTAT3, ETV5 and miR155 in KD-CAL+ group were higher than those in KD-CAL- group (P<0. 05), while the levels of SOCS1 and SOCS3 in KD-CAL+ group were lower than those in KD-CAL- group (P<0. 05). IVIG therapy restored the indexes mentioned above to some extent (P<0. 05). (3) Compared with the healthy subjects, the levels of inflammatory cytokines (IL-6, IL-23 and TNF-α) in plasma and the expressions of surface receptors (TLR4, IL-6Rα/gp130, IL-23R/IL-23Rβ1 and TNFR1) and its downstream adaptors (MyD88, TRIF, RIP1) in CD4+T cells were up-regulated in patients with acute KD (P<0. 05), but were down-regulated significantly after IVIG treatment (P<0. 05). Moreo-ver, all of the indexes mentioned above in KD-CAL+ group were found to be higher than those in KD-CAL-group (P<0. 05). Conclusion Aberrant patterns of IL-17-associated histone methylation might be related to the immune dysfunction in patients with KD.

The effects of arsenic on histone modifications / 中华地方病学杂志

Arsenic is one of the important metalloid elements, which is widely distributed in nature. Arsenic can cause many health hazards. However, the toxic mechanisms of arsenic have not yet been fully understood. In recent years, many studies have shown that epigenetic regulation and control mechanism is associated with arsenic toxicity. Histone modification is an important epigenetic regulation and control mechanism, changes in its patterns may be one of the mechanisms by which arsenic alters the gene expression. We reviewed the effects of arsenic on regulation of histone methylation, acetylation, phosphorylation and ubiquitination.

Expression of SET8 in renal cell carcinoma tissue and its clinical significance / 医学研究生学报

Objective The occurrence and progression of renal cell carcinoma ( RCC) is complicated process associated with DNA abnormal methylation , histone modification , and Wnt signaling pathway .This study aimed to investigate the expression of histone methylase SET8 in RCC, its relationship with the Wnt signaling pathway , its action mechanism in RCC , and its clinical significance . Methods We selected 50 cases of RCC treated by radical nephrectomy , detected the expression of SET 8 in the RCC and adjacent noncancerous kidney tissues by immunohistochemical EliVision two-step staining with β-catenin.We compared the expression levels of SET8 and β-catenin in the two types of tissue and analyzed their relationship with the patients′clinical information and the pathologic stage and grade of tumor as well as the correlation between the SET 8 andβ-catenin expressions . Results SET8 was mainly express in the cytoplasm of the RCC and noncancerous kidney tissues , partially in the cell membrane and nucleus , while theβ-catenin protein chiefly in the cell membrane of renal tubular epithelial cells in the normal kidney tissue .The expression levels of SET 8 and β-catenin in the RCC tissue were closely related to the TNM stage and tumor grade (P0.05), but that of β-catenin was remarkably higher in the former (68%[34/50]) than in the latter (4%[2/50]) (P<0.01).There was a positive correlation between the positive expression of SET 8 and the abnormal expression of β-catenin (r=0.219, P<0.05). Conclusion SET8-activated H4K20me-1 controls the activation and abnormal activities of the Wnt signaling pathway , affects the gene transcription and cell activity , and participates in the occurrence , progression, and distant metastasis of RCC .

Histone acetylation and methylation modification of topoisomerase Ⅱαpromoter regulatory factor Sp1 in patients with chronic benzene poison-ing / 中国病理生理杂志

AIM:To investigate the histone modification changes of topoisomerase Ⅱα( TOPOⅡα) promoter regulatory factor Sp1 in the patients with chronic benzene poisoning .METHODS:The bone marrow samples were collect-ed from 25 chronic benzene poisoning cases and 25 controls.The chromatin immunoprecipitation assay was carried out to study the possible mechanism of TOPOⅡαpromoter regulatory factor Sp 1 expression changes .The mRNA expression of Sp1 was detected by RT-PCR.RESULTS:Compared with the controls , the histone H4 acetylation and histone H3 acetyla-tion of Sp1 in the chronic benzene poisoning patients significantly decreased (P0.05). The mRNA expression of Sp1 in the chronic benzene poisoning patients was significantly lower than that in the controls (P<0.05).CONCLUSION:In chronic benzene poisoning patients , the histone acetylation and methylation modification changes of TOPOⅡαpromoter regulatory factor Sp 1 accompanied with the changes of mRNA level are observed .Histone H4 and H3 acetylation and H3K9 methylation modification of Sp1 may play an important role in the benzene ’s hematopoiet-ic toxicities.

Influence of transcription factor Stat5a on proliferation of human breast cancer cells and its epigenetic mechanisms / 重庆医学

Objective To investigate and clarify the effect of Stat5a on proliferation of human breast cancer cells (MCF‐7) and to detect the changes of epigenetic signature on the promoter region of p53 gene .Methods Stat5a was over expressed in human breast cancer cells (MCF‐7) by using adenovirus mediated gene transfer technology .The cell proliferation was examined by MTS assay .ChIP assay was used to check the trimethylation of lysine 27 on histone 3 (H3K27Me3) of p53 gene promoter region .Fur‐thermore ,qRT‐PCR and western blot were also applied to confirm the expression of p53 gene .Results The number of MCF 7 in‐creased in a dose dependent manner .Compared with that of control group ,the cell density of MCF‐7 increased 7 .603 1% , 18 .123 7% and 24 .898 7% when the MOI were 10 ,20 and 30 .Chromatin Immunoprecipitation showed that Stat5a significantly in‐creased H3K27Me3 and down regulated the expression level of p53 gene .Conclusion Stat5a promotes proliferation of breast cancer cells through trimethylation of H3K27 and inhibition of p53 gene expression .

Expression and Regulation Mechanism of Vitamin D Receptor in Colorectal Cancer / 胃肠病学

Background:Vitamin D receptor( VDR)is a member of the steroid hormone receptor superfamily,which plays roles in various biological processes including cell proliferation,differentiation,apoptosis and immune responses,and is low expressed in many malignant tumors. Aims:To evaluate the expression and regulation mechanism of VDR in colorectal cancer. Methods:A total of 30 patients with colorectal cancer admitted from February 2010 to December 2012 at Ren Ji Hospital,School of Medicine,Shanghai Jiao Tong University were enrolled. Expression of VDR in cancerous tissue and para-cancer noncancerous tissue was determined by immunohistochemistry. Clinical data of 224 patients with colorectal cancer were collected from Gene Expression Omnibus( GEO)for analyzing the correlation between VDR expression in cancerous tissue and clinicopathological characteristics as well as survival time. Expression of VDR in human colon cancer cell lines HCT116 and SW620 transfected with enhancer of zeste homolog 2( EZH2 )-siRNA or treated with 5-azacytidine (5-AZA)was determined by real-time PCR,and methylation level of VDR promoter was determined by methylation-specific PCR( MSP). Results:Positivity rate of VDR was significantly lower in colorectal cancer tissue than that in para-cancer noncancerous tissue( 26. 7% vs. 70. 0%,P < 0. 001 ). Expression of VDR was negatively correlated with histological staging,distant metastasis,vascular metastasis and lymph node metastasis of colorectal cancer(P<0. 05). Survival time was significantly longer in patients with high expression of VDR than patients with low expression of VDR (P=0. 032). Compared with cells transfected with control-siRNA,expression of EZH2 mRNA and methylation level of VDR promoter in HCT116 and SW620 cells transfected with EZH2-siRNA were significantly decreased(P<0. 05),and expression of VDR mRNA was significantly increased(P<0. 05). Compared with negative control group,methylation level of VDR promoter in HCT116 and SW620 cells treated with 5-AZA was significantly decreased(P<0. 05),and expression of VDR mRNA was significantly increased(P<0. 05). Conclusions:Expression of VDR in colorectal cancer is down-regulated and positively correlated with a favourable prognosis. Transcriptional repression of VDR in colorectal cancer is co-regulated by histone methylation and DNA methylation.

Histones and histone modifications of retina conditions and disorders / 中华实验眼科杂志

Retina conditions and disorders,such as age-related macular degeneration (AMD),diabetic retinopathy (DR),retinitis pigmentosa (RP) and retinal or choroidal tumors,are relevant diseases to retinal neurons and vasculatures.Although genetic factors such as gene mutation and single nucleotide polymorphisms cause changes of gene expression and involve in the pathogenesis of certain retinal diseases,the alteration of gene expression can be observed without changing the genome sequences under the external or internal stimuli.This epigenetic role,especially histones and its modification,has been considered as a part of mechanisms of those diseases described above.Current advances have drawn our attentions to this field in both pathological and therapeutical challenges of retinal diseases.

EZH2 plays a role in HSC-T6 cell proliferation and activation affecting MAPK/ERK and PI3 K/AKT pathway / 中国药理学通报

Aim To investigate the effects of cell pro-liferation and activation in HSC-T6 cells by inhibiting the expression of EZH2 , and its partial relevant mech-anism. Methods By introducing the inhibitor DZNep in activated HSC-T6 cells stimulated by TGF-β1 , the protein expression levels of EZH2, p-ERK, p-AKT andα-SMA were detected by Western blot. The siRNA targeting EZH2 was designed and synthesized according to its nucleotide sequence, and their corresponding ex-pression vectors were constructed and transfected into HSC-T6 cells with LipofectamineTM 2000. The prolifer-ation of HSC-T6 cells was determined by MTT. And the protein expression levels of EZH2, p-ERK, p-AKT and α-SMA were measured by Western blot. Results By introducing the inhibitor DZNep in activated HSC-T6 cells stimulated by TGF-β1 , it effectively de-creased the protein levels of EZH2 and also the protein levels of p-ERK, p-AKT and α-SMA. By introducing EZH2-siRNA in activated HSC-T6 cells, it effectively inhibited the cell proliferation, and also the protein levels of EZH2, p-ERK, p-AKT andα-SMA. Conclu-sion Silencing EZH2 expression inhibits HSC-T6 cell proliferation and activation, and EZH2 may be a poten-tial therapeutic target gene for hepatic fibrosis.

Epigenetic regulation of estrogen receptor-αin breast cancer / 实用肿瘤学杂志

Recently,in the management of estrogen receptor(ER)positive breast canner,endocrine thera-py is the main treatment method;and estrogen receptor -α( ER-α) has obtained popularity as one of the most common targets .There are many known risk factors for ER function in breast canner such as ER gene mutation ;unbalanced microenvironment;signal transduction pathway disorders .While more and more attention is paid to the changes in ER expression and function induced by epigenetic aberrations .ER gene promoter methylation induces down regulation and deletion in ER expression ,which has not only a most highly incidence in epigenetic aberra-tions,but also a widen degree of research .Histone modification could influence ER -αexpression and function , either.However,the special mirco RNAs(miRNAs)are also implicated in the regulation of ER -α,and affect the therapy of tamoxifen in breast tumor .

Regulation of DU145 prostate cancer cell growth by Scm-like with four mbt domains 2.

Mammalian SFMBTs have been considered to be polycomb group repressors. However, molecular mechanisms underlying mammalian SFMBTs-mediated gene regulation and their biological function have not been characterized. In the present study, we identified YY1 and methylated histones as interacting proteins of human SFMBT2. We also found that human SFMBT2 binds preferentially to methylated histone H3 and H4 that are associated with transcriptional repression. Using DU145 prostate cancer cells as a model, we showed that SFMBT2 has a transcriptional repression activity on HOXB13 gene expression. In addition, occupancy of SFMBT2 coincided with enrichment of diand tri-methylated H3K9 and H4K20 as well as tri-methylated H3K27 at the HOXB13 gene promoter. When SFMBT2 was depleted by siRNA in DU145 prostate cancer cells, significant up-regulation of HOXB13 gene expression and decreased cell growth were observed. Collectively, our findings indicate that human SFMBT2 may regulate cell growth via epigenetic regulation of HOXB13 gene expression in DU145 prostate cancer cells.