Upregulation Of EZH2 Research Articles

EZH2 promotes hepatocellular carcinoma progression through modulating miR-22/galectin-9 axis

BackgroundRecent studies have shown that interferon-γ (IFN-γ)-induced galectin-9 expression in Kupffer cells plays an essential role in modulatingthe microenvironment of hepatitis-associated hepatocellular carcinoma (HCC). However, whether or not IFN-γ induces galectin-9 expression in HCC cells, its biological role and regulatory mechanism in HCC development and progression are poorly defined.MethodsQuantitative PCR and western blotting analysis were used to detect galectin-9 and EZH2 levels in HCC cell lines stimulated with IFN-γ. Bioinformatics analysis and luciferase reporter assay were utilized to confirmthe binding ofmiR-22 to the 3′ untranslated region (3’-UTR) of galectin-9. The methylation status of miR-22 promoter was analyzed by MSP (Methylation specific PCR) and BSP (bisulfite sequencing PCR), while chromatin immunoprecipitation (ChIP) assay identify the occupation status of EZH2 and H3K27me3 at the promoter. Furthermore, the effect of ectopic expression of galectin-9 and miR-22 on cell proliferation, migration, invasion and cell apoptosis was assessed by using CCK-8, transwell assays and flow cytometric analysis, respectively.ResultsIFN-γ induces up-regulation of galectin-9 and EZH2 in HCC cell lines. Galectin-9 is a target of miR-22 and EZH2 facilitates galectin-9 expression by tri-methylation of H3K27 on miR-22 promoter but not hyper-methylation status of DNA. MiR-22 overexpression suppressed HCC cell growth, invasion, and metastasis both in vitro and in vivo. Interestingly, galectin-9 also exhibited antitumor effects, and restoring galectin-9 expression in miR-22 overexpressing cells strengthened its antitumor effects.ConclusionsThese findings indicated that EZH2 facilitates galectin-9 expression by epigenetically repressing miR-22 and that galectin-9, which is known as an immunosuppressant, also functions as a tumor suppressor in HCC.

Long non-coding RNA LOC554202 modulates chordoma cell proliferation and invasion by recruiting EZH2 and regulating miR-31 expression.

Chordoma is a rare malignant bone tumour arising from notochordal remnants. Long non-coding RNA LOC554202, as the host gene of miR-31, contributes to various cancer developments. However, little is known about the biological function of LOC554202 in chordoma. Here, the relationship between LncRNA LOC554202, miR-31 and EZH2 was elucidated in chordoma. The levels of LOC554402, miR-31, EZH2, RNF144B, and epithelial-mesenchymal transition (EMT) markers were measured in chordoma tissues and the chordoma cell lines via quantitative real-time PCR (qRT-PCR) or Western blot. FISH assay demonstrated the LOC554402 expression in chordoma tissues. The chordoma cell lines, U-CH1 and JHC7, were transfected with siRNA or miRNA mimics and analysed for cell proliferation ability, apoptosis, cell migration, and invasion. RNA pull down, RIP assay, and Luciferase Reporter Assay were used to analyze the interaction between LOC554202 and EZH2. Animal tumour xenografts were generated, and qRT-PCR was performed to investigate EZH2, miR-31, and RNB144B expression on tumour growth in vivo. We found elevated expression of LOC554202 was associated with a decreased level of miR-31 in cancer tissues. Knockdown of LOC554202 or overexpression of miR-31 suppressed the proliferation, migration, and invasion of chordoma cells. Unexpectedly, EZH2 as a binding protein of LOC554202, and it was positively regulated by LOC554202, leading to the reduced expression of miR-31. Furthermore, the impaired function of miR-31 restored expression of the oncogene RNF144B and maintained the metastasis-promoting activity in vitro. The results in vivo confirmed the anti-tumour effects of knockdown of LOC554202, which inhibited EZH2/miR-31 to activate the oncogene RNF144B. Our results suggest that LOC554202 may play an important role in the progression of chordoma by the direct upregulation of EZH2 and indirect promotion of RNF144B via miR-31.

Enhancer of Zeste homolog 2 (EZH2) induces epithelial-mesenchymal transition in endometriosis

EZH2, a subunit of the polycomb repressive complex 2 (PRC2) catalyzing trimethylation of histone H3 lysine 27 (H3K27), induces epithelial-mesenchymal transition (EMT) in cancers. However, whether EZH2 regulates EMT in endometriosis is unclear. Here, we show that EZH2 expression, along with its associated PRC2 proteins, is significantly elevated in ectopic and eutopic endometrium from women with endometriosis as compared with control endometrium. EZH2 knockdown or inhibition restored the epithelial phenotypes of endometriotic epithelial cells, concomitant with the upregulation of E-cadherin and downregulation of vimentin and transcription factors (Snail and Slug) as well as reduced cellular migratory and invasive propensity. Conversely, overexpression of EZH2 induced the expression of Snail, Slug and vimentin and suppresses E-cadherin expression. In vivo administration of 3-Deazaneplanocin A (DZNep), an EZH2 inhibitor, significantly inhibited the growth of endometriotic lesions and improved generalized hyperalgesia, along with attenuated EMT and reduced fibrosis in endometriosis. Notably, platelets induced EZH2 upregulation and increased H3K27 and H3K9 trimethylation levels in endometriotic epithelial cells. These data identify EZH2 as a novel driver of EMT in endometriosis, implicates the link between wound healing and epigenetic changes in the context of endometriosis, and underscore the role of platelets in the development of endometriosis.

Abstract 5326: EZH2 regulation through lysine 63 linked ubiquitination in prostate cancer

Abstract Enhancer of zeste homolog 2 (EZH2) plays crucial roles on the development of cells and tissues as well as the progression of prostate cancer (PCa) and castration resistant prostate cancer (CRPC). EZH2 can upregulate and activate progenitor genes including androgen receptor (AR) and the target genes. However, the mechanisms by which EZH2 is regulated in PCa remain elusive. Literature reports that tumor necrosis factor (TNF) receptor associated factor 6 (TRAF6) is essential for both normal tissue development and regulation of oncogenic signaling pathways in cancers. In this study, we reported that EZH2 is regulated by PTEN and SKP2 network in PCa. Specifically, we showed that the aberrant upregulation of EZH2 and histone H3 lysine 27 trimethylation (H3K27me3) in both Pten null mouse embryonic fibroblasts (MEFs) in vitro and prostate tumors of Pten null mice in vivo, as compared to the controls. EZH2 levels were negatively correlated with TRAF6 in human PCa cells upon SKP2 dysregulation. Immunofluorescence (IF) staining results showed a co-localization of EZH2 and TRAF6 in nucleus of PC3 cells, and co-immunoprecipitation (co-IP) analysis further confirmed a physical binding of EZH2 and TRAF6 in PC3 cells. Ectopic expression of TRAF6 promoted the K63-linked polyubiquitination of EZH2 to decrease EZH2 and H3K27me3 levels in PCa cells. Conversely, TRAF6 knockdown resulted in a reduction of EZH2 polyubiquitination with an increase of EZH2 and H3K27me3 levels in PCa cells. Furthermore, the catalytically dead mutant TRAF6 C70A abolished the TRAF6-mediated polyubiquitination of human EZH2 in vivo in 293T cells and in vitro in the recombinant human EZH2 protein, as compared with TRAF6 WT. Together, we report for the first time a novel mechanism on EZH2 ubiquitination and an important signaling network of SKP2-TRAF6-EZH2-H3K27me3 in PCa cells. Our findings provide valuable clues on the mechanism and efficiency of targeting EZH2 in PCa and CRPC . Note: This abstract was not presented at the meeting. Citation Format: Wenfu Lu, Shenji Lu, Bo Li, Yingqiu Xie, Michael G. Izban, Billy R. Ballard, Sandeep A. Sathyanarayana, Samuel E. Adunyah, Robert J. Matusik, Zhenbang Chen. EZH2 regulation through lysine 63 linked ubiquitination in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5326. doi:10.1158/1538-7445.AM2017-5326

MP71-06 PROGNOSTIC SIGNIFICANCE OF EZH2 EXPRESSION IN UPPER TRACT UROTHELIAL CARCINOMA

You have accessJournal of UrologyBladder Cancer: Upper Tract Transitional Cell Carcinoma I1 Apr 2017MP71-06 PROGNOSTIC SIGNIFICANCE OF EZH2 EXPRESSION IN UPPER TRACT UROTHELIAL CARCINOMA Ahmet Aydin, Nirmish Singla, Vandana Panwar, Ryan Hutchinson, Solomon Woldu, Christopher Wood, Jose Karam, Alon Weizer, Jay Raman, Mesut Remzi, Nathalie Rioux-Leclercq, Andrea Haitel, Marco Roscigno, Christian Bolenz, Karim Bensalah, Arthur Sagalowsky, Shahrokh Shariat, Yair Lotan, Aditya Bagrodia, Payal Kapur, Vitaly Margulis, and Laura-Maria Krabbe Ahmet AydinAhmet Aydin More articles by this author , Nirmish SinglaNirmish Singla More articles by this author , Vandana PanwarVandana Panwar More articles by this author , Ryan HutchinsonRyan Hutchinson More articles by this author , Solomon WolduSolomon Woldu More articles by this author , Christopher WoodChristopher Wood More articles by this author , Jose KaramJose Karam More articles by this author , Alon WeizerAlon Weizer More articles by this author , Jay RamanJay Raman More articles by this author , Mesut RemziMesut Remzi More articles by this author , Nathalie Rioux-LeclercqNathalie Rioux-Leclercq More articles by this author , Andrea HaitelAndrea Haitel More articles by this author , Marco RoscignoMarco Roscigno More articles by this author , Christian BolenzChristian Bolenz More articles by this author , Karim BensalahKarim Bensalah More articles by this author , Arthur SagalowskyArthur Sagalowsky More articles by this author , Shahrokh ShariatShahrokh Shariat More articles by this author , Yair LotanYair Lotan More articles by this author , Aditya BagrodiaAditya Bagrodia More articles by this author , Payal KapurPayal Kapur More articles by this author , Vitaly MargulisVitaly Margulis More articles by this author , and Laura-Maria KrabbeLaura-Maria Krabbe More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.2262AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Enhancer of zeste homolog 2 is a methyltransferase encoded by the EZH2 gene. The role of EZH2 upregulation has been studied in several malignancies, including bladder cancer, though its role in upper tract urothelial carcinoma (UTUC) is poorly understood. We sought to evaluate the prognostic value of EZH2 expression in UTUC. METHODS We reviewed a multi-institutional cohort of patients who underwent radical nephroureterectomy (RNU) for high-grade UTUC from 1990-2008. Immunohistochemistry for EZH2 was performed on tissue microarrays from RNU specimens. The percentage of staining was evaluated, with EZH2 positivity defined as >20% staining present. Clinicopathologic characteristics and oncologic outcomes including recurrence-free (RFS), cancer-specific (CSS), and overall survival (OS) were compared between patients stratified by EZH2 positivity. Prognostic role of EZH2 was assessed using Kaplan-Meier (KM) analysis. Predictors of oncologic outcomes were identified using univariate (UVA) and multivariate (MVA) Cox regression analysis. Significance was defined for p<0.05. RESULTS 402 patients were included for analysis, with median follow-up 35.5 months. 313 (77.9%) patients were EZH2-negative and 89 (22.1%) were EZH2-positive. While gender, pT stage, pN stage, and prior bladder cancer were similar between groups, EZH2 expression was more often associated with ureteral location, sessile architecture, necrosis, and CIS (Table). On UVA, EZH2 was a significant predictor for worse RFS (HR 1.63, p=0.019), CSS (HR 1.87, p=0.004), and OS (HR 1.97, p<0.001). On MVA adjusted for age, pT, pN, and LVI, EZH2 remained a significant predictor for worse OS (HR 1.65, p=0.005), while significance was lost for RFS and CSS. KM curves are shown (Figure). CONCLUSIONS EZH2 expression appears to be associated with adverse pathologic features and may predict worse oncologic outcomes in patients with high-grade UTUC. The role of EZH2 pathways in UTUC pathogenesis remains to be further elucidated. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e947 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Ahmet Aydin More articles by this author Nirmish Singla More articles by this author Vandana Panwar More articles by this author Ryan Hutchinson More articles by this author Solomon Woldu More articles by this author Christopher Wood More articles by this author Jose Karam More articles by this author Alon Weizer More articles by this author Jay Raman More articles by this author Mesut Remzi More articles by this author Nathalie Rioux-Leclercq More articles by this author Andrea Haitel More articles by this author Marco Roscigno More articles by this author Christian Bolenz More articles by this author Karim Bensalah More articles by this author Arthur Sagalowsky More articles by this author Shahrokh Shariat More articles by this author Yair Lotan More articles by this author Aditya Bagrodia More articles by this author Payal Kapur More articles by this author Vitaly Margulis More articles by this author Laura-Maria Krabbe More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Ulinastatin protects against lipopolysaccharide-induced cardiac microvascular endothelial cell dysfunction via downregulation of lncRNA MALAT1 and EZH2 in sepsis.

The present study aimed to evaluate the effects of ulinastatin on the permeability and apoptosis of lipopolysaccharide(LPS)-induced cardiac microvascular endothelial cells(CMVECs), and investigate its molecular mechanisms in sepsis. The sepsis rat model was induced by cecal ligation and puncture(CLP), and rat CMVECs were isolated and treated with LPS or/and ulinastatin. Then, cell permeability was evaluated by transendothelial electrical resistance, reactive oxygen species(ROS) levels were assessed by 2,7-dichlorofluorescein diacetate, cell apoptosis was detected using AnnexinV-FITC apoptosis detection kit, and the expression levels of Bcl-2, Bax, caspase-3, metastasis-associated lung adenocarcinoma transcript1 (MALAT1) and EZH2 were detected by RT-qPCR and/or western blotting. In addition, the relationship of MALAT1 and EZH2 was evaluated by RNA immunoprecipitation(RIP) assay and chromatin immunoprecipitation(ChIP) assay. Compared with LPS-induced CMVECs, treatment with ulinastatin significantly reduced CMVEC permeability and the percentage of apoptotic cells, as well as an increased level of Bcl-2 and inhibited the levels of ROS, caspase-3 and Bax (all p<0.05). In addition, long non-coding RNA(lncRNA) MALAT1 was confirmed to interact with EZH2 in CMVECs. Overexpression of lncRNA MALAT1 and EZH2 was found in the hearts of the sepsis rat and LPS-induced CMVECs, while ulinastatin inhibited the upregulation of lncRNA MALAT1 and EZH2 in the LPS-induced CMVECs (all p<0.05). Ulinastatin protected against LPS-induced CMVEC cell hyperpermeability and apoptosis via downregulation of lncRNA MALAT1 and EZH2 in sepsis.

Integrated genomic analyses of de novo pathways underlying atypical meningiomas

Meningiomas are mostly benign brain tumours, with a potential for becoming atypical or malignant. On the basis of comprehensive genomic, transcriptomic and epigenomic analyses, we compared benign meningiomas to atypical ones. Here, we show that the majority of primary (de novo) atypical meningiomas display loss of NF2, which co-occurs either with genomic instability or recurrent SMARCB1 mutations. These tumours harbour increased H3K27me3 signal and a hypermethylated phenotype, mainly occupying the polycomb repressive complex 2 (PRC2) binding sites in human embryonic stem cells, thereby phenocopying a more primitive cellular state. Consistent with this observation, atypical meningiomas exhibit upregulation of EZH2, the catalytic subunit of the PRC2 complex, as well as the E2F2 and FOXM1 transcriptional networks. Importantly, these primary atypical meningiomas do not harbour TERT promoter mutations, which have been reported in atypical tumours that progressed from benign ones. Our results establish the genomic landscape of primary atypical meningiomas and potential therapeutic targets.

NFIB Mediates BRN2 Driven Melanoma Cell Migration and Invasion Through Regulation of EZH2 and MITF

While invasion and metastasis of tumour cells are the principle factor responsible for cancer related deaths, the mechanisms governing the process remain poorly defined. Moreover, phenotypic divergence of sub-populations of tumour cells is known to underpin alternative behaviors linked to tumour progression such as proliferation, survival and invasion. In the context of melanoma, heterogeneity between two transcription factors, BRN2 and MITF, has been associated with phenotypic switching between predominantly invasive and proliferative behaviors respectively. Epigenetic changes, in response to external cues, have been proposed to underpin this process, however the mechanism by which the phenotypic switch occurs is unclear. Here we report the identification of the NFIB transcription factor as a novel downstream effector of BRN2 function in melanoma cells linked to the migratory and invasive characteristics of these cells. Furthermore, the function of NFIB appears to drive an invasive phenotype through an epigenetic mechanism achieved via the upregulation of the polycomb group protein EZH2. A notable target of NFIB mediated up-regulation of EZH2 is decreased MITF expression, which further promotes a less proliferative, more invasive phenotype. Together our data reveal that NFIB has the ability to promote dynamic changes in the chromatin state of melanoma cells to facilitate migration, invasion and metastasis.

Molecular Mechanism behind the Synergistic Activity of Proteasome Inhibition and PRC2 Inhibition in the Treatment of Multiple Myeloma

Proteasome inhibitors (PIs) such as bortezomib and carfilzomib play a central role in the treatment of multiple myeloma (MM). However, the almost inevitable resistance to PIs necessitates the search for novel strategies to improve patient outcome. The methyltransferase EZH2 and its homolog EZH1 are components of polycomb repressive complex 2 (PRC2), inducing H3K27me3 and repressing the transcription of target genes. Recent studies have linked EZH2 to tumorigenesis including MM. In this study, we investigated the molecular mechanism of PRC2 inhibition as a partner of PIs for the treatment of MM.We first examined the impact of proteasome inhibition on EZH2. Bortezomib as well as carfilzomib remarkably decreased EZH2 protein, and downregulated its mRNA in dose- and time-dependent manners. As EZH2 is a downstream target of E2F1, the effects of bortezomib on RB-E2F pathway were investigated. Bortezomib downregulated E2F1 protein and mRNA with notable decrease of phosphorylated RB protein, due to accumulation of cyclin-dependent kinase inhibitors such as p21 and p27. ChIP assay revealed that bortezomib significantly inhibited the binding of E2F1 to EZH2 promoter, and E2F1 overexpression resulted in upregulation of EZH2 in MM cells. These data suggest that bortezomib transcriptionally downregulates EZH2 via modulating RB-E2F pathway.Next we used lentiviral vectors to overexpress EZH2 in RPMI8226 cells and observed diminished sensitivity to bortezomib in EZH2-overexpressing cells compared to cells transduced with an empty vector. Remarkably, the combined treatment of bortezomib and UNC1999, a dual inhibitor of EZH2 and EZH1, restored the sensitivity of MM cells to bortezomib. Notably, UNC1999 enhanced the cytotoxicity induced by bortezomib in vitro and in vivo partly through enhanced apoptosis. Carfilzomib also demonstrated strong synergy with UNC1999 in vitro, suggesting broad application of this strategy.To characterize the mechanism of action of PRC2 inhibition alone and in combination with proteasome inhibition, we performed RNA sequencing (RNA-seq) of MM.1S cells treated with UNC1999, bortezomib or the combination of both agents versus DMSO-treated cells and chromatin immunoprecipitation sequencing (ChIP-seq) for H3K27me3 of UNC1999 versus DMSO-treated MM.1S cells. Importantly, we identified the direct targets of UNC1999 as those with significantly enhanced expression (>1.5 fold UNC1999/Control) and remarkable reduction of H3K27me3 (≥ 2-fold). These genes included NR4A1, EGR1 and LTB. EGR1 and LTB are known tumor suppressor candidates in MM, while NR4A1 is implicated in myeloid and lymphoid malignancies. Upregulation of NR4A1 and reduction of H3K27me3 at the NR4A1promotor were confirmed using manual RT-PCR and ChIP, respectively. Notably, overexpression of NR4A1 significantly inhibited the growth of MM cells, suggesting a tumor suppressive role for NR4A1 in MM. Notably, MYC (c-Myc), a major contributor to the pathogenesis of MM, was greatly downregulated in NR4A1-overexpressing cells. MYC is reportedly a direct target of NR4A1 that suppresses its expression. We found that UNC1999 downregulated MYC mRNA and protein. Moreover, the combination of UNC1999 and bortezomib remarkably suppressed MYC-related gene sets.Gene set enrichment analysis (GSEA) showed that while PRC2 genes were positively enriched in UNC1999- and combination-treated cells, they were not significantly enriched in bortezomib-treated cells. In addition, although bortezomib downregulated EZH2, EZH1 and H3K27me3 mark were not affected in bortezomib-treated cells. This suggested that inhibition of EZH2 alone is not enough to completely suppress PRC2 function. Therefore, we compared the combination of bortezomib and UNC1999 with that of bortezomib and a specific EZH2 inhibitor, GSK126. UNC1999 induced much better synergistic activity with bortezomib than GSK126 as evidenced by the combination index, associated with further reduction of the levels of H3K27me3. This underlines the importance of dual inhibition of EZH2 and EZH1 to fully block PRC2 activity.In conclusion, our findings demonstrate that the combination of dual inhibition of EZH2 and EZH1 together with proteasome inhibition cooperatively blocks PRC2 function, resulting in derepression of tumor suppressors such as NR4A1 and inhibition of MYC. Thus, this combination is a promising new therapeutic option for the treatment of MM. DisclosuresNo relevant conflicts of interest to declare.

Development and Molecular Analysis of Synthetic Lethality By Targeting EZH1 and EZH2 in Non-Hodgkin Lymphomas

Epigenetic program is a molecular basis of cellular identity and functions. We have shown the transcriptome (Cancer Cell, 2012) and the underlying histone methylation patterns (Blood, 2016) of adult T-cell leukemia-lymphoma (ATL). The epigenetic landscape of ATL is defined as "genome-wide H3K27me3 accumulation". Similar accumulation has been detected in multiple cancers, particularly in hematological malignancies. Relief of the cumulative methylation may restore the aberrant transcriptome to ideal expression signature, leading to a promising treatment. Due to variation characteristics, EZH2 is recognized as a druggable target. However, extrinsic regulation of methylation pattern is still challenging without knowledge of molecule(s) and their combination that needs to be targeted to reprogram the epigenome in anticipation of synthetic lethality.To redefine the conventional concept, we first examined expression and global occupancy patterns of H3K27 methyltransferases EZH1 and EZH2. EZH2 expression was low in CD4+ T cells and significantly high in ATL. In contrast, basal EZH1 was very high in mature lymphocytes compared with undifferentiated lineages and also high in ATL. ChIP-on-chip analysis revealed significant changes in distributions of both EZH1 and EZH2 in primary ATL cells, which caused abnormal H3K27me3 accumulation. Importantly, over 80% of H3K27me3 are specifically induced by either EZH1 (28.9%) or EZH2 (14.4%), or by both (39.3%). Moreover, they have differential functions by regulating specific targets; EZH2 suppresses various transcription regulators, establishing complex gene regulatory network. EZH1 would rather directly induce H3K27me3 at genes involving functional processes such as lymphocyte activation. We detected EZH1 and EZH2 in functional polycomb repressive complex 2 (PRC2) in ATL and DLBCL cells. Unexpectedly, EZH1/2 were co-localized with H3K4me3 at a small population of the lymphoma genome. The "EZH1/2 + H3K4me3" non-canonical targets such as cell cycle activators were highly expressed in ATL.We next compared functions of EZH1/2. Single depletion of EZH1 or EZH2 suppressed T- and B-lymphoma cell proliferation, which supports their unique functions. The broad reduction of H3K27me3 was achieved by EZH2 inhibition; however, genome-wide ChIP demonstrated that EZH2 inhibition or depletion triggered strong compensatory action of EZH1, followed by rebound accumulation of H3K27me3 at many functional genes in EZH1+ lymphoma cells. We found that a transcription factor YY1 affects PRC2 recruitment and EZH1 compensation after EZH2 inhibition. Double depletion of EZH1+EZH2 or YY1+EZH2 surmounted the epigenetic homeostasis. In addition, depletion of EZH1 significantly enhanced effects of EZH2 inhibitors in ATL and DLBCL cells (5.47~205-fold). These data indicate requirements for the aberrant epigenome, namely, fluctuating EZH2 (upregulation or mutation) and underlying stable EZH1.We have succeeded in developing an unprecedented EZH1/2 dual-inhibitor (IC50 9.0 nM (EZH1); 10 nM (EZH2)). The new drug successfully inhibited genome-wide EZH1/2 occupancies without compensation, resulting in effective H3K27me3 reduction and gene reactivation compared with the single inhibitor. Of note, the dual-inhibitor suppressed expression of the non-canonical EZH1/2 + H3K4me3 target genes. Besides H3K27me3 reprogramming, EZH1/2 inhibition could modulate genes through H3K4me3 regulation and indirect influence on the secondary regulatory network and signaling pathways such as NF-kB.The EZH1/2 dual-inhibitor significantly blocked primary ATL cell survival and in vivo tumor growth of ATL and DLBCL models. Furthermore, we evaluated drug efficacy in various models of hematological malignancies including ATL, DLBCL (EZH2 WT and mutant), Burkitt lymphoma, and PTCL, which are all originated from EZH1+ differentiated lymphocytes. All of them showed higher sensitivity against the EZH1/2 inhibitor compared with the EZH2 solo inhibitor (5.2~200-fold). We did not detect strong adverse effects in normal T cells.These integrated molecular and phenotypic analyses provide a novel concept "EZH1+EZH2 dual-targeting" and demonstrate validity of the new drug in the treatment of malignant lymphomas. Taking these results, a Phase I clinical trial against T- and B-cell non-Hodgkin lymphomas including ATL is now under way in Japan. DisclosuresYamagishi:Daiichi Sankyo Co., Ltd.: Research Funding. Honma:Daiichi Sankyo Co., Ltd.: Employment. Adachi:Daiichi Sankyo Co., Ltd.: Employment. Ohsugi:Daiichi Sankyo Co., Ltd.: Research Funding. Utsunomiya:Daiichi Sankyo Co., Ltd.: Speakers Bureau. Tsukasaki:Daiichi Sankyo Co., Ltd.: Consultancy; Takeda: Research Funding. Tobinai:Zenyaku Kogyo: Honoraria; Takeda: Honoraria, Research Funding; Mundipharma KK: Honoraria, Research Funding; Kyowa Hakko Kirin: Research Funding; Celgene: Research Funding; Daiichi Sankyo Co., Ltd.: Consultancy; SERVIER: Research Funding; Ono Pharmaceutical: Research Funding; Eisai: Honoraria, Research Funding; Chugai Pharma: Research Funding; Abbvie: Research Funding; Janssen Pharmaceuticals: Honoraria, Research Funding; GlaxoSmithKline: Research Funding; HUYA Bioscience: Honoraria. Araki:Daiichi Sankyo Co., Ltd.: Employment.

STAT3 signaling drives EZH2 transcriptional activation and mediates poor prognosis in gastric cancer.

BackgroundSTAT3 signaling plays the pivotal role in tumorigenesis through EZH2 epigenetic modification, which enhanced STAT3 activity by increased tyrosine phosphorylation of STAT3. Here, another possible feedback mechanism and clinical significance of EZH2 and STAT3 were investigated in gastric cancer (GC).MethodsSTAT3, p-STAT3 (Tyr 705) and EZH2 expression were examined in 63 GC specimens with matched normal tissues by IHC staining. EZH2 and STAT3 were also identified in five GC cell lines using RT-PCR and western blot analyses. p-STAT3 protein was detected by western blotting. In order to investigate whether EZH2 expression was directly regulated by STAT3, EZH2 expression was further detected using siRNA for STAT3 or IL-6 stimulation, with dual luciferase reporter analyses, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assays. The clinical significance of STAT3, p-STAT3 and EZH2 expression was evaluated by multi-factor COX regression and Kaplan-Meier analyses.ResultsHyper-activation of STAT3, p-STAT3 and EZH2 expression were observed in GC cells and tissues. STAT3 signaling was correlated with EZH2 expression in GC (R = 0.373, P = 0.003), which was consistent with our data showing that STAT3 as the transcriptional factor enhanced EZH2 transcriptional activity by binding the relative promoter region (-214 ~ -206). STAT3 was an independent signature for poor survival (P = 0.002). Patients with STAT3+/EZH2+ or p-STAT3+/EZH2+ had a worse outcome than others (P < 0.001); Besides, high levels of STAT3 and EZH2 was associated with advanced TNM staging (P = 0.017). Moreover, treatment with a combination of siSTAT3 and EZH2-specific inhibitor, 3-deazaneplanocin A (DZNEP), increased the apoptotic ratio of cells. It is benefit for targeting STAT3-EZH2 interplay in GC treatment.ConclusionsOur results indicate that STAT3 status mediated EZH2 upregulation, associated with advanced TNM stage and poor prognosis, suggesting that combination with knockdown of STAT3 and EZH2 inhibitor might be a novel therapy in GC treatment. Collectively, STAT3, p-STAT3 and EZH2 expression were provided for the precision medicine in GC patients.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-016-0561-z) contains supplementary material, which is available to authorized users.

SKP2 loss destabilizes EZH2 by promoting TRAF6-mediated ubiquitination to suppress prostate cancer.

EZH2 is crucial for the progression of prostate cancer (PCa) and castration-resistant prostate cancer (CRPC) through upregulation and activation of progenitor genes, as well as androgen receptor (AR)-target genes. However, the mechanisms by which EZH2 is regulated in PCa and CRPC remain elusive. Here we report that EZH2 is post-transcriptionally regulated by SKP2 in vitro in cultured cells and in vivo in mouse models. We observed aberrant upregulation of Skp2, Ezh2 and histone H3 lysine 27 trimethylation (H3K27me3) in both Pten null mouse embryonic fibroblasts (MEFs) and Pten null mouse prostate tissues. Loss of Skp2 resulted in a striking decrease of Ezh2 levels in Pten/Trp53 double-null MEFs and in prostate tumors of Pten/Trp53 double-null mutant mice. SKP2 knockdown decreased EZH2 levels in human PCa cells through upregulation of TRAF6-mediated and lysine(K) 63-linked ubiquitination of EZH2 for degradation. Ectopic expression of TRAF6 promoted the K63-linked ubiquitination of EZH2 to decrease EZH2 and H3K27me3 levels in PCa cells. In contrast, TRAF6 knockdown resulted in a reduced EZH2 ubiquitination with an increase of EZH2 and H3K27me3 levels in PCa cells. Furthermore, the catalytically dead mutant TRAF6 C70A abolished the TRAF6-mediated polyubiquitination of recombinant human EZH2 in vitro. Most importantly, a concurrent elevation of Skp2 and Ezh2 was found in CRPC tumors of Pten/Trp53 mutant mice, and expression levels of SKP2 and EZH2 were positively correlated in human PCa specimens. Taken together, our findings revealed a novel mechanism on EZH2 ubiquitination and an important signaling network of SKP2-TRAF6-EZH2/H3K27me3, and targeting SKP2-EZH2 pathway may be a promising therapeutic strategy for CRPC treatment.

Identification of transcription factors (TFs) and targets involved in the cholangiocarcinoma (CCA) by integrated analysis.

The present study was designed to investigate the upstream transcription factors (TFs) and the signature genes in cholangiocarcinoma (CCA), providing better clues on the regulatory mechanisms and therapeutic applications. Gene expression data sets of CCA were searched in the Gene Expression Omnibus database for integrated analysis. Functional annotation of differently expressed genes (DEGs) was then conducted and the TFs were identified. Moreover, a global transcriptional regulatory network of TFs-targets was constructed. Integrated analysis of five eligible Gene Expression Omnibus data sets led to a set of 993 DEGs and 48 TFs in CCA. The constructed TFs-targets regulatory network consisted of 697 TF-target interactions between 41 TFs and 436 DEGs. The top 10 TFs covering the most downstream DEGs were NFATC2, SOX10, ARID3A, ZNF263, NR4A2, GATA3, EGR1, PLAG1, STAT3 and FOSL1, which may have important roles in the tumorigenesis of CCA. Supporting the fact that defects of cell-cycle surveillance mechanism were closely related to various cancers, we found that cell cycle was the most significantly enriched pathway. KCNN2 and ADCY6 were involved in the bile secretion. Thus, their aberrant expression may be closely related to the pathogenesis of CCA. Particularly, we found that upregulation of EZH2 in CCA is a powerful potential marker for CCA.

MicroRNA-298 inhibits malignant phenotypes of epithelial ovarian cancer by regulating the expression of EZH2.

MicroRNA (miRNA or miR)-298 has been reported to be downregulated and to modify the expression of the polycomb protein enhancer of zeste 2 (EZH2) in recurrent epithelial ovarian cancer (EOC). To date, no functional evidence of a miR-298-EZH2 axis in EOC has been documented. The present study aimed to investigate the associations of miR-298 and/or EZH2 expression with clinicopathological features of EOC patients, and revealed their roles in cell motility based on EOC cell lines. Reverse transcription-quantitative polymerase chain reaction was performed to detect the expression levels of miR-298 and EZH2 messenger RNA in human EOC tissues and cell lines. Wound healing and transwell assays were performed to determine the function of the miR-298-EZH2 axis on cell migration and invasion, respectively. Compared with normal tissues, miR-298 expression was significantly downregulated, while EZH2 expression was significantly upregulated, in human EOC tissues (both P=0.001). In addition, miR-298 downregulation and EZH2 upregulation were significantly associated with high clinical stage (both P=0.01) and pathological grade (both P=0.02) of EOC patients. Furthermore, the ectopic expression of miR-298 could efficiently inhibit cell migration and invasion. Notably, the overexpression of EZH2 could restore the cell migration and invasion abilities suppressed by miR-298. Our data offer convincing evidence that the dysregulation of the miR-298-EZH2 axis may be important in tumor progression of EOC patients. The present study also confirmed a tumor-suppressive role of miR-298 in modulating EOC cell motility by regulating the expression of EZH2, implying its potential as a novel miRNA-based therapeutic target for the treatment of human EOC.

Abstract 4534: Taxol therapy-induced catalytic EZH2 limits therapeutic responses in PTEN null prostate cancer

Abstract Prostate cancer (PCa) is the most common cancer and a major cause of cancer related deaths in men in North America. The phosphatase and tensin homolog gene (PTEN) is frequently inactivated in PCa. Approximately 40% of primary and 70% of metastatic PCa's have genomic alterations in the PI3K-signaling, mostly through the loss of PTEN. Majority of metastatic PCa associated with PTEN loss are treated with docetaxel; an FDA approved therapy for recurrent PCa. However, in PTEN null PCa docetaxel treatment enhances senescence and does not significantly impact tumor volume. These findings were further confirmed in PCa patients with decreased levels of PTEN. In order to understand the global impact of docetaxel in PTEN null PCa we performed an unbiased RNA-seq of prostate tissues harvested from docetaxel treated prostate specific PTEN null mice. Data analysis showed strong enrichment of chromatin modifying enzymes reactome, mainly PRC2 as one of the top ranked categories. Among them EZH2, an oncogenic methyltransferase was found to be significantly upregulated. Quantitative PCR analysis confirmed statistically significant upregulation of EZH2 in docetaxel treated mice compared to vehicle control. EZH2 upregulation was independent of androgen levels as both androgen dependent and independent cells showed striking upregulation of EZH2 when treated with docetaxel. Next, we confirmed the nature of the upregulated EZH2 (catalytic or non-catalytic) by docetaxel. EZH2 methyltransferase activity assay data showed significant induction of methyltransferase activity by docetaxel in both androgen dependent and independent conditions and in PTEN null mouse tissues. Further, we measured other methyltransferase marks i.e. H3K27me1&amp;2, H3K4me3, H3K9me3 in the presence of docetaxel and found only specific upregulation of H3K27me3, confirming upregulation of only catalytic EZH2 by docetaxel. These data suggested a need for co-targeting EZH2 during docetaxel treatment in PTEN null PCa conditions. In order to provide a proof-of-principle we performed a tumor xenograft study in nude mice implanted with PTEN null PC3 cells. Combination of DZNeP (an EZH2 inhibitor) and docetaxel significantly inhibited tumor growth compared to each agent alone. Results obtained from the xenograft studies prompted us to perform a preclinical study in prostate specific PTEN null mice. Data obtained from this study clearly showed a significant reduction in number of high grade lesions in PTEN null tumors in combination group when compared to either docetaxel or DZNeP treated mice. We also observed clearance of senescent cells and accumulation of CD8+ T cells and classical dendritic (CD8+ Clec9a+ positive) cells. Our data suggests the necessity of designing a combination therapy of targeting EZH2 during docetaxel treatment specifically, which will likely increase the efficacy of docetaxel in PTEN null PCa. Citation Format: Mohammad Imran Khan, Abid Hamid, Vaqar Mustafa Adhami, Chloe Lang, Hasan Mukhtar. Taxol therapy-induced catalytic EZH2 limits therapeutic responses in PTEN null prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4534.

MiR-340 impedes the progression of laryngeal squamous cell carcinoma by targeting EZH2

Laryngeal squamous cell carcinoma (LSCC) is a common malignant tumor of the otolaryngeal region and accounts for 1–2% of all malignancies diagnosed worldwide. miR-340 down-regulation and EZH2 up-regulation have been frequently identified in multiple cancers, but the role of miR-340 and EZH2 in LSCC has not been explored. In this study, we investigated the regulative role of miR-340 in EZH2 expression and LSCC progression. The results showed that EZH2 was up-regulated and miR-340 was down-regulated in both Hep-2 cells and LSCC tissues. Molecularly, our results confirmed that miR-340 directly targeted EZH2 gene and inhibited EZH2 expression. MTT assay and BrdU assay showed that miR-340 transfection reduced the cell proliferation ability of Hep-2 cells. The transwell assay indicated that the invasion and migration ability of Hep-2 cells was dramatically inhibited by miR-340 transfection. In addition, miR-340 transfection induced cell apoptosis with concomitant enhancement of Bax, increase of Caspase-3 expression and activity, and reduction of Bcl-2 expression in Hep-2 cells. Both miR-340 transfection and EZH2 knockdown induced p27 expression and suppressed PI3K/Akt activation in Hep-2 cells. Strikingly, EZH2 knockdown reduced cell proliferation, and EZH2 overexpression significantly rescued the miR-340-mediated suppressive effect on cell proliferation. Moreover, miR-340 could obviously induce the inhibition of Hep-2 cell-derived tumor growth and EZH2/p27 expression ratio in vivo. Taken together, these data suggest that miR-340 impedes LSCC progression by targeting EZH2 with the possible mechanism to enhance the expression of anti-oncogene p27 and suppress PI3K/Akt activation, providing a novel target and a potential therapeutic pathway against LSCC.

EZH2 dependent epigenetic landscape in adult T cell leukemia and Tax immortalized cells

Epigenetic regulations globally determine gene transcription. Recent studies have revealed that expression changes and genetic mutations of epigenetic factors cause epigenetic imbalance in cancers. We previously reported that aberrant expression of Polycomb repressive complex 2 (PRC2) components causes constitutive NF-κB activation through silencing of miR-31 in ATL cells. However, the underlying mechanisms by which the epigenetic imbalance is induced and maintained remain to be elucidated. Here, we conducted ChIP-on-chip and transcriptome analyses of ATL and normal CD4+ T cells and found that the epigenetic reprogramming closely associates with ATL specific gene expression signature. Leukemic cell-specific silencing of cell cycle regulator, CDNK1A, was correlated with H3K27me3 level. In addition, orchestrated loss of microRNAs and multiple transcription factors appears to be mediated by the epigenetic mechanism. EZH2 upregulation and H3K27me3 accumulation were found in HTLV-1-infected populations derived from ATL patients as well as asymptomatic carriers. Furthermore, EZH2 inhibition blocked Tax-dependent cell growth and its immortalization in vitro. Intriguingly, the Tax-triggered immortalizing cells partially mimicked the methylation pattern observed in ATL cells, suggesting that the epigenetic alterations are closely involved in immortalization of infected cells and disease progression. In parallel, we found that over expression of PRC2 core components was induced by active signaling cascades including NF-κB in ATL cells. Collectively, our results suggest a coherent positive feedback mechanism comprised of PRC2 and NF-κB signaling, which stabilizes the epigenetic rearrangement and phenotypic outcomes in HTLV-1 infected cells. Since pharmacological inhibition of EZH2 selectively killed ATL and HTLV-1 infected cells in ex vivo culture, targeting the epigenetic elements will hold great promise in treatment and prevention of ATL and HTLV-1-related diseases.

Abstract 4063: The oncogenic cell cycle-related kinase promotes tumor immune escape via modulation of myeloid-derived suppressor cells in hepatocellular carcinoma

Abstract Hepatocellular carcinoma (HCC) is a sexually dimorphic cancer significantly associated with elevated levels of male sex hormone androgen and pro-inflammatory cytokine interleukin-6 (IL-6) (ref 1). Our previous genome-wide location and functional analysis has pinpointed cell cycle-related kinase (CCRK) as a critical mediator of androgen receptor (AR) oncogenic activity in HCC through a self-reinforcing circuitry involving β-catenin and the Polycomb repressor enhancer of zeste 2 (EZH2) (ref 2-4). As these key circuit players have also been shown to trigger inflammatory response and aggressiveness of HCC cells (ref 5,6), we aimed to investigate whether CCRK modulates tumor microenvironment during hepatocarcinogenesis. Expression profiling of 16 pro-inflammatory cytokines and chemokines revealed that ectopic expression of wild-type but not kinase-defective CCRK significantly induced the production of IL-6, IL-1β, tumor necrosis factor-α and cyclooxygenase 2 in immortal hepatic and HCC cells. Rescue experiments showed that CCRK-induced IL-6 production was dependent on EZH2 up-regulation and subsequent nuclear factor-κB activation. Based on the causal link between IL-6 and myeloid-derived suppressor cells (MDSCs), we next examined the relationship between CCRK and MDSCs in vitro and in vivo. By co-culturing CCRK-expressed or silenced hepatic and HCC cell lines with peripheral blood mononuclear cells (PBMCs) isolated from healthy donors, we found that CCRK stimulated the expansion of Lin-CD33+CD11b+HLA-DR-MDSCs from PBMCs by flow cytometry analysis. The induced MDSCs also showed higher suppressive activity against CD3+ T cell proliferation. In a high-fat diet-fed mouse model exposed to low-dose carcinogen diethylnitrosamine, administration of lentivirus expressing short-hairpin (sh)RNA against Ccrk significantly reduced &amp;gt;70% obesity-promoted tumor multiplicity and size compared to mice treated with control shRNA (p&amp;lt;0.01). Notably, Ccrk down-regulation also significantly reduced the population of circulating CD11b+Gr-1intMDSCs in the mice (p&amp;lt;0.05). In summary, our findings demonstrate that the oncogenic CCRK in hepatic cells can promote MDSC expansion and suppressive functions possibly via IL-6 production. Such tumor-stromal cell interaction provides survival advantage of cancer cells via immune escape. In conclusion, CCRK not only functions as a signaling hub but also an immunoregulator, thus representing a new cancer immunotherapy target.

Abstract 173: SOX4 interacts with EZH2 and HDAC3 to suppress microRNA-31 in invasive esophageal cancer cells

Abstract Tumor metastasis is responsible for 90% of cancer-related deaths. A strong link between microRNA dysregulation and human cancers has recently been established. However, the molecular mechanisms through which microRNAs regulate metastasis and cancer progression remain unclear. We analyzed the reciprocal expression regulation of miR-31 and SOX4 in esophageal squamous and adenocarcinoma cell lines by qRT-PCR and Western Blotting using overexpression and shRNA knock-down approaches. Here we report that SOX4 promotes esophageal tumor cell proliferation and invasion by silencing miR-31 via activation and stabilization of a co-repressor complex with EZH2 and HDAC3. We demonstrate that miR-31 is significantly decreased in invasive esophageal cancer cells compared to non-invasive cell lines, while upregulation of miR-31 inhibits growth, migration and invasion of esophageal adenocarcinoma (EAC) and squamous cell carcinoma (ESCC) cell lines. miR-31, in turn, targets SOX4 for degradation by directly binding to its 3′-UTR. Additionally, miR-31 regulates EZH2 and HDAC3 indirectly. SOX4, EZH2 and HDAC3 levels inversely correlate with miR-31 expression in ESCC cell lines. Ectopic expression of miR-31 in ESCC and EAC cell lines leads to down regulation of SOX4, EZH2 and HDAC3. Conversely, pharmacologic and genetic inhibition of SOX4 and EZH2 restore miR-31 expression. We show that SOX4, EZH2 and HDAC3 form a co-repressor complex that binds to the miR-31 promoter, repressing miR-31 through an epigenetic mark by H3K27me3 and by histone acetylation. Clinically, when compared to normal adjacent tissues, esophageal tumor samples show upregulation of SOX4, EZH2, and HDAC3, and EZH2 expression is significantly increased in metastatic ESCC tissues. Thus, we identified a novel molecular mechanism by which the SOX4, EZH2 and miR-31 circuit promotes tumor progression and potential therapeutic targets for invasive esophageal carcinomas. Citation Format: Rainelli B. Koumangoye, Thomas Andl, Kenneth J. Taubenslag, Steven T. Zilberman, Chase Taylor, Claudia D. Andl. SOX4 interacts with EZH2 and HDAC3 to suppress microRNA-31 in invasive esophageal cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 173. doi:10.1158/1538-7445.AM2015-173

Abstract 3517: Honokiol inhibits bladder tumor growth by suppressing EZH2/miR-143 axis

Abstract EZH2, a histone H3K27 methyltransferase, plays an essential role in regulation of cell proliferation, survival, invasiveness and cancer stem cell (CSC) maintenance. The upregulation of the histone methyltransferase EZH2 is frequently detected in various cancer types, including urinary bladder cancer (UBC). However, the mechanisms underlying its role in cancer cell are not yet fully understood. Honokiol, a biologically active biphenolic compound isolated from the Magnolia spp, has been linked with anticancer activities; however, its mechanisms is poorly understood. In this study, we investigated the in vitro and in vivo effects of honokiol on UBC cells and whether honokiol can modulate EZH2 mediated network. By employing MTT, colony formation, wound healing, transwell invasion, Western blot, and Aldofluor stem cell detection assays, honokiol was shown to inhibit human UBC cell proliferation, survival, CSC maintenance, migration and invasion. Immunoblotting assay showed that the reduction of EZH2 expression level by honokiol was correlated with the decreases of MMP9, CD44, Sox2, Notch1. Forced expression of EZH2 reversed honokiol induced cell growth arrest and low clonogenicity, indicating that EZH2 is a major downstream target for honokiol in UBC cells. Since EZH2 is essential for gene expression repression, we screened 24 cancer related miRNAs and found that tumor suppressor miR-143 was the most induced miRNA by honokiol treatment. Further quantitative RT-PCR, chromatin immunoprecipitation (ChIP) and functional analysis revealed that EZH2 directly inhibited the expression of miR-143, whereas the inhibition of miR-143 partially rescued the EZH2 knockdown-induced cell growth arrest and reduced clonogenicity. Moreover, in vivo investigation using xenograft analysis in athymic nude mice indicated that honokiol treatment inhibited tumor progression, which was associated with reduced EZH2, CD44, Sox2, Notch1 and MMP9, and increased expression of miR-143. Altogether, our data indicated that honokiol inhibited human UBC tumor growth and aggressiveness through suppression of EZH2 function and induction of its target, miR-143, and that honokiol is promising candidate for chemoprevention and/or therapeutic treatment for bladder cancer. Citation Format: Jun Yan, Qing Zhang, Wei Zhao, Changxiao Ye, Cunjie Chang, Xiaojing Huang, Junlong Zhuang, Jiannan Song, Yangyan Cui, Isaac Eliaz, Bing Shen, Ruimin Huang, Hao Ying, Hongqian Guo. Honokiol inhibits bladder tumor growth by suppressing EZH2/miR-143 axis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3517. doi:10.1158/1538-7445.AM2015-3517