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Background: SUZ12 is one of the core members of the polycomb repressive complex 2 (PRC2), but its expression and role in lung adenocarcinoma (LUAD) are unclear. We aimed to explore the expression, prognosis, biological functions and roles of SUZ12 in LUAD. Methods: The expression of SUZ12 was detected by immunohistochemical staining, qRT‐PCR, and western blotting in LUAD tissues and cells. The biological functions and molecular mechanisms of SUZ12 were characterized by a range of in vitro and in vivo experiments. Results: SUZ12 was overexpressed in LUAD tissues, and high SUZ12 expression was correlated with worse clinicopathological features and a poorer prognosis. Knockdown of SUZ12 significantly inhibited cell growth, colony formation, invasion, and migration, and induced apoptosis and G1/S phase arrest, while overexpression of SUZ12 had the opposite effects. Knockdown of SUZ12 decreased the tumorigenic capacity of A549 cells in vivo. The expression of key signaling molecules related to the cell cycle, apoptosis, migration, and immunity were altered by the knockdown or overexpression of SUZ12. SUZ12 can directly bind to the Bax promoter region, EZH2 and H3K27me3 levels dependents on SUZ12. The expression levels of SUZ12 and Bax were negatively correlated in LUAD tissues. Conclusions: SUZ12 is a new oncogene related to the poor prognosis of LUAD. SUZ12 regulates LUAD progression by regulating the expression of related signaling molecules, and as a part of the PRC2 complex, it may bind to the Bax promoter to silence Bax expression. [ABSTRACT FROM AUTHOR]

Imagawa-Matsumoto syndrome (IMMAS; MIM #618786) is an autosomal dominant syndrome characterized by overgrowth, dysmorphic features, musculoskeletal abnormalities, developmental delay, and intellectual disability. The first case was reported in 2017 and has subsequently been diagnosed in only another 12 patients. We also present the first IMMAS patient from Turkey. A 19-year-old female was admitted to the neurology outpatient clinic due to a behavioral disorder and intellectual disability. Her physical examination revealed macrocephaly and dysmorphic features like a round face, broad forehead, hypertelorism, and variable skeletal anomalies such as flat feet, clinodactyly, and macrocephaly. Cranial magnetic resonance imaging (MRI) showed agenesis of the corpus callosum and polymicrogyria. Chromosomal analysis results were consistent with a normal constitutional female karyotype and microarray analysis showed a de novo 1.5-MB size deletion on the long arm of chromosome 17; band q11.2 encompassing the Polycomb Repressive Complex 2 Subunit (SUZ12 gene, MIM *606245). This report will contribute to the limited information in the literature. [ABSTRACT FROM AUTHOR]

Abstract Background SUZ12 is one of the core members of the polycomb repressive complex 2 (PRC2), but its expression and role in lung adenocarcinoma (LUAD) are unclear. We aimed to explore the expression, prognosis, biological functions and roles of SUZ12 in LUAD. Methods The expression of SUZ12 was detected by immunohistochemical staining, qRT‐PCR, and western blotting in LUAD tissues and cells. The biological functions and molecular mechanisms of SUZ12 were characterized by a range of in vitro and in vivo experiments. Results SUZ12 was overexpressed in LUAD tissues, and high SUZ12 expression was correlated with worse clinicopathological features and a poorer prognosis. Knockdown of SUZ12 significantly inhibited cell growth, colony formation, invasion, and migration, and induced apoptosis and G1/S phase arrest, while overexpression of SUZ12 had the opposite effects. Knockdown of SUZ12 decreased the tumorigenic capacity of A549 cells in vivo. The expression of key signaling molecules related to the cell cycle, apoptosis, migration, and immunity were altered by the knockdown or overexpression of SUZ12. SUZ12 can directly bind to the Bax promoter region, EZH2 and H3K27me3 levels dependents on SUZ12. The expression levels of SUZ12 and Bax were negatively correlated in LUAD tissues. Conclusions SUZ12 is a new oncogene related to the poor prognosis of LUAD. SUZ12 regulates LUAD progression by regulating the expression of related signaling molecules, and as a part of the PRC2 complex, it may bind to the Bax promoter to silence Bax expression.

BACKGROUND: While Alzheimers disease (AD) pathology is associated with altered brain structure, it is not clear whether gene expression changes mirror the onset and evolution of pathology in distinct brain regions. Deciphering the mechanisms which cause the differential manifestation of the disease across different regions has the potential to help early diagnosis. OBJECTIVE: We aimed to identify common and unique endotypes and their regulation in tangle-free neurons in sporadic AD (SAD) across six brain regions: entorhinal cortex (EC), hippocampus (HC), medial temporal gyrus (MTG), posterior cingulate (PC), superior frontal gyrus (SFG), and visual cortex (VCX). METHODS: To decipher the states of tangle-free neurons across different brain regions in human subjects afflicted with AD, we performed analysis of the neural transcriptome. We explored changes in differential gene expression, functional and transcription factor target enrichment, and co-expression gene module detection analysis to discern disease-state transcriptomic variances and characterize endotypes. Additionally, we compared our results to tangled AD neuron microarray-based study and the Allen Brain Atlas. RESULTS: We identified impaired neuron function in EC, MTG, PC, and VCX resulting from REST activation and reversal of mature neurons to a precursor-like state in EC, MTG, and SFG linked to SOX2 activation. Additionally, decreased neuron function and increased dedifferentiation were linked to the activation of SUZ12. Energetic deficit connected to NRF1 inactivation was found in HC, PC, and VCX. CONCLUSIONS: Our findings suggest that SAD manifestation varies in scale and severity in different brain regions. We identify endotypes, such as energetic shortfalls, impaired neuronal function, and dedifferentiation.

Enhancing cardiomyocyte proliferation is essential to reverse or slow down the heart failure progression in many cardiovascular diseases such as myocardial infarction (MI). Long non-coding RNAs (lncRNAs) have been reported to regulate cardiomyocyte proliferation. In particular, lncRNA urothelial carcinoma-associated 1 (lncUCA1) played multiple roles in regulating cell cycle progression and cardiovascular diseases, making lncUCA1 a potential target for promoting cardiomyocyte proliferation. However, the role of lncUCA1 in cardiomyocyte proliferation remains unknown. This study aimed at exploring the function and underlying molecular mechanism of lncUCA1 in cardiomyocyte proliferation. Quantitative RT-PCR showed that lncUCA1 expression decreased in postnatal hearts. Gain-and-loss-of-function experiments showed that lncUCA1 positively regulated cardiomyocyte proliferation in vitro and in vivo. The bioinformatics program identified miR-128 as a potential target of lncUCA1, and loss of miR-128 was reported to promote cardiomyocyte proliferation by inhibiting the SUZ12/P27 pathway. Luciferase reporter assay, qRT-PCR, western blotting, and immunostaining experiments further revealed that lncUCA1 acted as a ceRNA of miR-128 to upregulate its target SUZ12 and downregulate P27, thereby increasing cyclin B1, cyclin E, CDK1 and CDK2 expression to promote cardiomyocyte proliferation. In conclusion, upregulation of lncRNA UCA1 promoted cardiomyocyte proliferation by inhibiting the miR-128/SUZ12/P27 pathway. Our results indicated that lncUCA1 might be a new therapeutic target for stimulating cardiomyocyte proliferation.

Abstract Background Cisplatin (CDDP)-based chemotherapy is a standard first-line treatment for metastatic bladder cancer (BCa) patients, and chemoresistance remains a major challenge in clinical practice. Circular RNAs (circRNAs) have emerged as essential regulators in carcinogenesis and cancer progression. However, the role of circRNAs in mediating CDDP chemosensitivity has yet to be well elucidated in BCa. Methods CircSTX6 (hsa_circ_0007905) was identified by mining the public circRNA datasets and verified by Sanger sequencing, agarose gel electrophoresis, RNase R treatment and qRT-PCR assays. Then, function experiments were performed to evaluate the effects of circSTX6 on BCa metastasis. Luciferase reporter assay, RNA pull-down, RNA immunoprecipitation (RIP), RNA stability assay, Fluorescence in situ hybridization (FISH) and Immunofluorescence (IF) were conducted to evaluate the interaction among circSTX6, miR-515-3p, PABPC1 and SUZ12. Animal experiments were performed to explore the function of circSTX6 in tumor metastasis and CDDP sensitivity. Results We identified that circSTX6 was significantly upregulated in clinical samples and cells of BCa. Functionally, circSTX6 promoted cell migration and invasion both in vitro and in vivo. Mechanistically, circSTX6 could act as a miR-515-3p sponge and abolish its effect on SUZ12. Moreover, circSTX6 was confirmed to increase the stability of SUZ12 mRNA by interacting with a mRNA stabilizer PABPC1 and subsequently promote the expression of SUZ12. Importantly, silencing of circSTX6 improved the chemosensitivity of CDDP-resistant bladder cancer cells to CDDP. Furthermore, in vivo analysis supported that knockdown of circSTX6 attenuated CDDP resistance in BCa tumors. Conclusion These studies demonstrate that circSTX6 plays a pivotal role in BCa metastasis and chemoresistance, and has potential to serve as a therapeutic target for treatment of BCa.

Background: Cisplatin (CDDP)-based chemotherapy is a standard first-line treatment for metastatic bladder cancer (BCa) patients, and chemoresistance remains a major challenge in clinical practice. Circular RNAs (circRNAs) have emerged as essential regulators in carcinogenesis and cancer progression. However, the role of circRNAs in mediating CDDP chemosensitivity has yet to be well elucidated in BCa. Methods: CircSTX6 (hsa_circ_0007905) was identified by mining the public circRNA datasets and verified by Sanger sequencing, agarose gel electrophoresis, RNase R treatment and qRT-PCR assays. Then, function experiments were performed to evaluate the effects of circSTX6 on BCa metastasis. Luciferase reporter assay, RNA pull-down, RNA immunoprecipitation (RIP), RNA stability assay, Fluorescence in situ hybridization (FISH) and Immunofluorescence (IF) were conducted to evaluate the interaction among circSTX6, miR-515-3p, PABPC1 and SUZ12. Animal experiments were performed to explore the function of circSTX6 in tumor metastasis and CDDP sensitivity. Results: We identified that circSTX6 was significantly upregulated in clinical samples and cells of BCa. Functionally, circSTX6 promoted cell migration and invasion both in vitro and in vivo. Mechanistically, circSTX6 could act as a miR-515-3p sponge and abolish its effect on SUZ12. Moreover, circSTX6 was confirmed to increase the stability of SUZ12 mRNA by interacting with a mRNA stabilizer PABPC1 and subsequently promote the expression of SUZ12. Importantly, silencing of circSTX6 improved the chemosensitivity of CDDP-resistant bladder cancer cells to CDDP. Furthermore, in vivo analysis supported that knockdown of circSTX6 attenuated CDDP resistance in BCa tumors. Conclusion: These studies demonstrate that circSTX6 plays a pivotal role in BCa metastasis and chemoresistance, and has potential to serve as a therapeutic target for treatment of BCa. [ABSTRACT FROM AUTHOR]

Weaver syndrome (WS), an overgrowth/intellectual disability syndrome (OGID), is caused by pathogenic variants in the histone methyltransferase EZH2, which encodes a core component of the Polycomb repressive complex-2 (PRC2). Using genome-wide DNA methylation (DNAm) data for 187 individuals with OGID and 969 control subjects, we show that pathogenic variants in EZH2 generate a highly specific and sensitive DNAm signature reflecting the phenotype of WS. This signature can be used to distinguish loss-of-function from gain-of-function missense variants and to detect somatic mosaicism. We also show that the signature can accurately classify sequence variants in EED and SUZ12, which encode two other core components of PRC2, and predict the presence of pathogenic variants in undiagnosed individuals with OGID. The discovery of a functionally relevant signature with utility for diagnostic classification of sequence variants in EZH2, EED, and SUZ12 supports the emerging paradigm shift for implementation of DNAm signatures into diagnostics and translational research.

The SUZ12 gene encodes a subunit of polycomb repressive complex 2 (PRC2) that is essential for development by silencing the expression of multiple genes. Germline heterozygous variants in SUZ12 have been found in Imagawa–Matsumoto syndrome (IMMAS) characterized by overgrowth and multiple dysmorphic features. Similarly, both EZH2 and EED also encode a subunit of PRC2 each and their pathogenic variants cause Weaver syndrome and Cohen–Gibson syndrome, respectively. Clinical manifestations of these syndromes significantly overlap, although their different prevalence rates have recently been noted: generalized overgrowth, intellectual disability, scoliosis, and excessive loose skin appear to be less prevalent in IMMAS than in the other two syndromes. We could not determine any apparent genotype–phenotype correlation in IMMAS. The phenotype of neurofibromatosis type 1 arising from NF1 deletion was also shown to be modified by the deletion of SUZ12, 560 kb away. This review deepens our understanding of the clinical and genetic characteristics of IMMAS together with other overgrowth syndromes related to PRC2. We also report on a novel IMMAS patient carrying a splicing variant (c.1023+1G>C) in SUZ12. This patient had a milder phenotype than other previously reported IMMAS cases, with no macrocephaly or overgrowth phenotypes, highlighting the clinical variation in IMMAS. [ABSTRACT FROM AUTHOR]

Abstract Background Long non-coding RNAs (lncRNAs) are implicated in the development of multiple cancers. In our previous study, we demonstrated that HDAC1/4-mediated silencing of microRNA-200b (miR-200b) enhances docetaxel (DTX)-resistance of human lung adenocarcinoma (LAD) cells. Methods and results Herein, we probed the function of LncRNA MARCKSL1–2 (MARCKSL1-transcript variant 2, NR_052852.1) in DTX resistance of LAD cells. It was found that MARCKSL1–2 expression was markedly reduced in DTX-resistant LAD cells. Through gain- or loss- of function assays, colony formation assay, EdU assay, TUNEL assay, and flow cytometry analysis, we found that MARCKSL1–2 suppressed the growth and DTX resistance of both parental and DTX-resistant LAD cells. Moreover, we found that MARCKSL1–2 functioned in LAD through increasing miR-200b expression and repressing HDAC1. Mechanistically, MARCKSL1–2 recruited the suppressor of zeste 12 (SUZ12) to the promoter of histone deacetylase 1 (HDAC1) to strengthen histone H3 lysine 27 trimethylation (H3K27me3) of HDAC1 promoter, thereby reducing HDAC1 expression. MARCKSL1–2 up-regulated miR-200b by blocking the suppressive effect of HDAC1 on the histone acetylation modification at miR-200b promoter. Furthermore, in vivo analysis using mouse xenograft tumor model supported that overexpression of MARCKSL1–2 attenuated the DTX resistance in LAD tumors. Conclusions We confirmed that MARCKSL1–2 alleviated DTX resistance in LAD cells by abolishing the inhibitory effect of HDAC1 on miR-200b via the recruitment of SUZ12. MARCKSL1–2 could be a promising target to improve the chemotherapy of LAD. Graphical abstract

In acute myeloid leukemia (AML), treatment decisions are currently made according to the risk classification of the European LeukemiaNet (ELN), which is based on genetic alterations. Recently, optical genome mapping (OGM) as a novel method proved to yield a genome-wide and detailed cytogenetic characterization at the time of diagnosis. A young female patient suffered from a rather unexpected aggressive disease course under FLT3 targeted therapy in combination with induction chemotherapy. By applying a “next-generation diagnostic workup“ strategy with OGM and whole-exome sequencing (WES), a DDX3X: MLLT10 gene fusion could be detected, otherwise missed by routine diagnostics. Furthermore, several aspects of lineage ambiguity not shown by standard diagnostics were unraveled such as deletions of SUZ12 and ARPP21, as well as T-cell receptor recombination. In summary, the detection of this particular gene fusion DDX3X: MLLT10 in a female AML patient and the findings of lineage ambiguity are potential explanations for the aggressive course of disease. Our study demonstrates that OGM can yield novel clinically significant results, including additional information helpful in disease monitoring and disease biology.

Paroxysmal nocturnal hemoglobinuria (PNH) is a disease involving hematopoietic stem cell membrane defects caused by acquired phosphatidylinositol glycan anchor biosynthesis class A (PIGA) mutations. In this study, 97 target genes were selected as a target gene panel and screened in 23 PNH patients via the sequencing of specific DNA target regions. Through functional analysis, we identified that suppressor‐of‐Zeste 12 (SUZ12) may be involved in the proliferation of PNH clones. mRNA and protein expression levels of SUZ12 and the trimethylation level of histone H3 at lysine 27 (H3K27) in CD59– peripheral blood leukocytes from PNH patients were higher than those in CD59+ cells from PNH patients and peripheral blood leukocytes from healthy controls. In addition, the relative expression of SUZ12 in PNH patients was positively correlated with Ret% and the proportion of PNH clones. When we knocked down SUZ12 expression in a PIGA knockdown THP‐1 cell line (THP‐1 KD cells), the trimethylation of histone H3K27(H3K27me3) and cell proliferation decreased, apoptosis increased, and cell cycle arrest occurred in G0/G1 phase. In conclusion, SUZ12 participates in the proliferation of PNH clones by regulating histone H3K27me3 levels. Our results may provide new therapeutic targets and possibilities for PNH patients. [ABSTRACT FROM AUTHOR]

Background: Long non-coding RNAs (lncRNAs) are implicated in the development of multiple cancers. In our previous study, we demonstrated that HDAC1/4-mediated silencing of microRNA-200b (miR-200b) enhances docetaxel (DTX)-resistance of human lung adenocarcinoma (LAD) cells. Methods and results: Herein, we probed the function of LncRNA MARCKSL1–2 (MARCKSL1-transcript variant 2, NR_052852.1) in DTX resistance of LAD cells. It was found that MARCKSL1–2 expression was markedly reduced in DTX-resistant LAD cells. Through gain- or loss- of function assays, colony formation assay, EdU assay, TUNEL assay, and flow cytometry analysis, we found that MARCKSL1–2 suppressed the growth and DTX resistance of both parental and DTX-resistant LAD cells. Moreover, we found that MARCKSL1–2 functioned in LAD through increasing miR-200b expression and repressing HDAC1. Mechanistically, MARCKSL1–2 recruited the suppressor of zeste 12 (SUZ12) to the promoter of histone deacetylase 1 (HDAC1) to strengthen histone H3 lysine 27 trimethylation (H3K27me3) of HDAC1 promoter, thereby reducing HDAC1 expression. MARCKSL1–2 up-regulated miR-200b by blocking the suppressive effect of HDAC1 on the histone acetylation modification at miR-200b promoter. Furthermore, in vivo analysis using mouse xenograft tumor model supported that overexpression of MARCKSL1–2 attenuated the DTX resistance in LAD tumors. Conclusions: We confirmed that MARCKSL1–2 alleviated DTX resistance in LAD cells by abolishing the inhibitory effect of HDAC1 on miR-200b via the recruitment of SUZ12. MARCKSL1–2 could be a promising target to improve the chemotherapy of LAD. [ABSTRACT FROM AUTHOR]

Abstract Background MicroRNAs are a class of non-coding RNAs that regulate gene expression through binding to mRNAs and preventing their translation. One family of microRNAs known as the miR-200 family is an important regulator of epithelial identity. The miR-200 family consists of five members expressed in two distinct clusters; the miR-200c/141 cluster and the miR-200b/200a/429 cluster. We have found that murine and human mammary tumor cells with claudin-low characteristics are associated with very low levels of all five miR-200s. Methods To determine the impact of miR-200s on claudin-low mammary tumor cells, the miR-200c/141 cluster and the miR-200b/200a/429 cluster were stably re-expressed in murine (RJ423) and human (MDA-MB-231) claudin-low mammary tumor cells. Cell proliferation and migration were assessed using BrdU incorporation and transwell migration across Matrigel coated inserts, respectively. miRNA sequencing and RNA sequencing were performed to explore miRNAs and mRNAs regulated by miR-200 re-expression while Enrichr-based pathway analysis was utilized to identify cellular functions modified by miR-200s. Results Re-expression of the miR-200s in murine and human claudin-low mammary tumor cells partially restored an epithelial cell morphology and significantly inhibited proliferation and cell invasion in vitro. miRNA sequencing and mRNA sequencing revealed that re-expression of miR-200s altered the expression of other microRNAs and genes regulated by SUZ12 providing insight into the complexity of miR-200 function. SUZ12 is a member of the polycomb repressor complex 2 that suppresses gene expression through methylating histone H3 at lysine 27. Flow cytometry confirmed that re-expression of miR-200s increased histone H3 methylation at lysine 27. Conclusions Re-expression of miR-200s in claudin-low mammary tumor cells alters cell morphology and reduces proliferation and invasion, an effect potentially mediated by SUZ12-regulated genes and other microRNAs.

Background and objectives: Esophageal squamous cell carcinoma (ESCC) is the most widespread type of esophageal cancer. LncRNA TUG1 was first identified in a genomic screening study for the treatment of taurine in retinal cells. This study aimed at analyzing TUG1 expression in ESCC tissues collected from an Iranian population of patients. Bioinformatics study was also conducted for better understanding the function of this lnc-RNA. Methods: We examined the expression of TUG1 in 31 pairs of ESCC tissues and adjacent non-cancerous tissues by qRT-PCR. Bioinformatics analysis was conducted using various databases. Student’s t-test was performed using SPSS software (version 16.0) to evaluate the difference in TUG1 expression between ESCC and adjacent non-cancerous tissues. Results: TUG1 expression level in ESCC tissues was significantly higher than that in the adjacent non-cancerous tissues (P=0.04). Conclusion: TUG1 is upregulated in ESCC, which may be related to history of smoking

Enhancement of protein synthesis from mRNA translation is one of the key steps supporting cardiomyocyte hypertrophy during cardiac remodeling. The methyltransferase-like5 (METTL5), which catalyzes m6A modification of 18S rRNA at position A1832, has been shown to regulate the efficiency of mRNA translation during the differentiation of ES cells and the growth of cancer cells. It remains unknown whether and how METTL5 regulates cardiac hypertrophy. In this study, we have generated a mouse model, METTL5-cKO, with cardiac-specific depletion of METTL5 in vivo. Loss function of METTL5 promotes pressure overload-induced cardiomyocyte hypertrophy and adverse remodeling. The regulatory function of METTL5 in hypertrophic growth of cardiomyocytes was further confirmed with both gain- and loss-of-function approaches in primary cardiomyocytes. Mechanically, METTL5 can modulate the mRNA translation of SUZ12, a core component of PRC2 complex, and further regulate the transcriptomic shift during cardiac hypertrophy. Altogether, our study may uncover an important translational regulator of cardiac hypertrophy through m6A modification.

Abstract Background Neural tube defects (NTDs) are severe, common birth defects that result from failure of normal neural tube closure during early embryogenesis. Accumulating strong evidence indicates that genetic factors contribute to NTDs etiology, among them, HOX genes play a key role in neural tube closure. Although abnormal HOX gene expression can lead to NTDs, the underlying pathological mechanisms have not fully been understood. Method We detected that H3K27me3 and expression of the Hox genes in a retinoic acid (RA) induced mouse NTDs model on E8.5, E9.5 and E10.5 using RNA-sequencing and chromatin immunoprecipitation sequencing assays. Furthermore, we quantified 10 Hox genes using NanoString nCounter in brain tissue of fetuses with 39 NTDs patients including anencephaly, spina bifida, hydrocephaly and encephalocele. Results Here, our results showed differential expression in 26 genes with a > 20-fold change in the level of expression, including 10 upregulated Hox genes. RT-qPCR revealed that these 10 Hox genes were all upregulated in RA-induced mouse NTDs as well as RA-treated embryonic stem cells (ESCs). Using ChIP-seq assays, we demonstrate that a decrease in H3K27me3 level upregulates the expression of Hox cluster A–D in RA-induced mouse NTDs model on E10.5. Interestingly, RA treatment led to attenuation of H3K27me3 due to cooperate between UTX and Suz12, affecting Hox gene regulation. Further analysis, in human anencephaly cases, upregulation of 10 HOX genes was observed, along with aberrant levels of H3K27me3. Notably, HOXB4, HOXC4 and HOXD1 expression was negatively correlated with H3K27me3 levels. Conclusion Our results indicate that abnormal HOX gene expression induced by aberrant H3K27me3 levels may be a risk factor for NTDs and highlight the need for further analysis of genome-wide epigenetic modification in NTDs.

Enhancing cardiomyocyte proliferation is essential to reverse or slow down the heart failure progression in many cardiovascular diseases such as myocardial infarction (MI). Long non-coding RNAs (lncRNAs) have been reported to regulate cardiomyocyte proliferation. In particular, lncRNA urothelial carcinoma-associated 1 (lncUCA1) played multiple roles in regulating cell cycle progression and cardiovascular diseases, making lncUCA1 a potential target for promoting cardiomyocyte proliferation. However, the role of lncUCA1 in cardiomyocyte proliferation remains unknown. This study aimed at exploring the function and underlying molecular mechanism of lncUCA1 in cardiomyocyte proliferation. Quantitative RT-PCR showed that lncUCA1 expression decreased in postnatal hearts. Gain-and-loss-of-function experiments showed that lncUCA1 positively regulated cardiomyocyte proliferation in vitro and in vivo . The bioinformatics program identified miR-128 as a potential target of lncUCA1, and loss of miR-128 was reported to promote cardiomyocyte proliferation by inhibiting the SUZ12/P27 pathway. Luciferase reporter assay, qRT-PCR , western blotting, and immunostaining experiments further revealed that lncUCA1 acted as a ceRNA of miR-128 to upregulate its target SUZ12 and downregulate P27, thereby increasing cyclin B1, cyclin E, CDK1 and CDK2 expression to promote cardiomyocyte proliferation. In conclusion, upregulation of lncRNA UCA1 promoted cardiomyocyte proliferation by inhibiting the miR-128/SUZ12/P27 pathway. Our results indicated that lncUCA1 might be a new therapeutic target for stimulating cardiomyocyte proliferation., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

Patients with germline neurofibromatosis type 1 (NF1) microdeletions frequently exhibit hereditary syndromes such as cardiovascular anomalies and have an increased risk of malignant peripheral nerve sheath tumors (MPNSTs). This study aimed to identify the genes codeleted with SUZ12 that are related to MPNST. We used differential gene expression and enrichment analyses to analyze the SUZ12-mutant and SUZ12-wild-type gene expression profiles in the GSE118186 and GSE66743 datasets in Gene Expression Omnibus (GEO). PPI network analysis combined with MPNST patient survival analysis was used to identify ADCY1, which catalyzes the conversion of ATP to cAMP, as a key gene. Moreover, chromatin immunoprecipitation sequencing (ChIP-Seq) showed that the distribution of H3K27me3 in the ADCY1 promoter region and gene body was significantly reduced in SUZ12-mutant cells. To verify the role of ADCY1 in SUZ12 mutation, we used RNA interference and plasmid transfection to interfere with SUZ12 expression in plexiform neurofibroma (pNF) and MPNST cell lines and then treated the cells with forskolin, IBMX and H89. ERK phosphorylation was accelerated and prolonged after siRNA transfection, especially in ipNF05.5 cells, and the intensity and duration of ERK activation were reduced after SUZ12 overexpression. Importantly, the level of p-ERK was consistent with that of Rap1-GTP. Moreover, H89 completely blocked Rap1 activation and the changes in the p-ERK level after SUZ12 siRNA transfection. In conclusion, our findings suggested that SUZ12 loss potentiates the effects of NF1 mutations by amplifying Ras signaling through the ADCY1/cAMP/Rap1/ERK pathway and that SUZ12 may serve as a therapeutic and prognostic biomarker in NF1-associated neurofibromas. [ABSTRACT FROM AUTHOR]

Background: Stem cell based therapy has been encouraged as an attractive method in regenerative medicine. Poor survival and maintenance of the cells transferred into the damaged tissue are broadly accepted as serious barriers to enhancing the efficacy of regenerative medicine. For this reason, some antioxidants such as L-carnitine (LC) are used as a favorite strategy to improve cell survival and retention properties. Aims: This study aims to evaluate the effect of LC on the expression of CD34 marker and its effect on apoptosis and SUZ12 gene expression. Methods: Rat bone marrow mono-nuclear cells (rBMNCs) were isolated. Then, CD34+ hematopoietic stem cells (HSCs) were enriched using the magnetic activated cell sorting (MACS) method. The cells were treated with 0.2 and 0.4 mM LC. Gene and protein expression levels of the CD34 were then measured by real-time PCR and flow cytometry, respectively. The percentage of apoptosis and SUZ12 gene expression were measured using the Annexin V/PI method and real-time PCR, respectively. Results: The results showed that in the experimental group, of the CD34+ HSCs treated with 0.2 mM LC, gene and protein expressions of CD34 increased by 1.7 fold and 0.49%, respectively. At the concentration of 0.4 mM, the early cell apoptosis increased by 25.9% (P<0.05). Also, in the concentration of 0.2 and 0.4 mM LC, the SUZ12 gene expression increased by 1.10 and 1.75 folds compared to the control group (P<0.05 and P<0.01), respectively. Conclusion: The results of this study could be used to improve chronic myeloid leukemia (CML) as a multidirectional therapeutic strategy. [ABSTRACT FROM AUTHOR]

Patients with germline neurofibromatosis type 1 (NF1) microdeletions frequently exhibit hereditary syndromes such as cardiovascular anomalies and have an increased risk of malignant peripheral nerve sheath tumors (MPNSTs). This study aimed to identify the genes codeleted with SUZ12 that are related to MPNST. We used differential gene expression and enrichment analyses to analyze the SUZ12-mutant and SUZ12-wild-type gene expression profiles in the GSE118186 and GSE66743 datasets in Gene Expression Omnibus (GEO). PPI network analysis combined with MPNST patient survival analysis was used to identify ADCY1, which catalyzes the conversion of ATP to cAMP, as a key gene. Moreover, chromatin immunoprecipitation sequencing (ChIP-Seq) showed that the distribution of H3K27me3 in the ADCY1 promoter region and gene body was significantly reduced in SUZ12-mutant cells. To verify the role of ADCY1 in SUZ12 mutation, we used RNA interference and plasmid transfection to interfere with SUZ12 expression in plexiform neurofibroma (pNF) and MPNST cell lines and then treated the cells with forskolin, IBMX and H89. ERK phosphorylation was accelerated and prolonged after siRNA transfection, especially in ipNF05.5 cells, and the intensity and duration of ERK activation were reduced after SUZ12 overexpression. Importantly, the level of p-ERK was consistent with that of Rap1-GTP. Moreover, H89 completely blocked Rap1 activation and the changes in the p-ERK level after SUZ12 siRNA transfection. In conclusion, our findings suggested that SUZ12 loss potentiates the effects of NF1 mutations by amplifying Ras signaling through the ADCY1/cAMP/Rap1/ERK pathway and that SUZ12 may serve as a therapeutic and prognostic biomarker in NF1-associated neurofibromas.

Abstract Background The deubiquitinating enzyme ubiquitin-specific protease 3 (USP3) plays a crucial role in numerous biological processes. The aberrant expression of USP3 may have an important role in tumor development. However, the mechanism by which USP3 promotes gastric cancer (GC) metastasis remains largely unknown. Methods Effects of USP3 on the progression of GC in vivo and in vitro and the potential underlying mechanisms have been investigated utilizing proteomics, RT-PCR, western blotting, immunohistochemistry, immunofluorescence, cell invasion and migration assays and xenograft tumor models. Results USP3 expression was upregulated in GC compared with matched normal tissues and was predictive of poor survival. USP3 also promoted migration and epithelial-to-mesenchymal transition (EMT) in GC cells. Moreover, TGF-β1 induced USP3 expression, and USP3 knockdown inhibited TGF-β1-induced EMT. Furthermore, we utilized Isobaric Tag for Relative and Absolute Quantitation (iTRAQ) to identify differentially expressed proteins in USP3-overexpressing cells compared with control cells. Importantly, we found that SUZ12 is indispensable for USP3-mediated oncogenic activity in GC. We observed that USP3 interacted with and stabilized SUZ12 via deubiquitination. SUZ12 knockdown inhibited USP3-induced migration and invasion, as well as EMT in GC cells. Examination of clinical samples confirmed that USP3 expression was positively correlated with SUZ12 protein expression and that the levels of USP3 or SUZ12 protein were negatively correlated with the levels of E-cadherin protein. Conclusions These findings identify USP3 as a critical regulator. The USP3-SUZ12 axis might promote tumor progression and could be a potential therapeutic candidate for human GC.

Background: MicroRNAs are a class of non-coding RNAs that regulate gene expression through binding to mRNAs and preventing their translation. One family of microRNAs known as the miR-200 family is an important regulator of epithelial identity. The miR-200 family consists of five members expressed in two distinct clusters; the miR-200c/141 cluster and the miR-200b/200a/429 cluster. We have found that murine and human mammary tumor cells with claudin-low characteristics are associated with very low levels of all five miR-200s. Methods: To determine the impact of miR-200s on claudin-low mammary tumor cells, the miR-200c/141 cluster and the miR-200b/200a/429 cluster were stably re-expressed in murine (RJ423) and human (MDA-MB-231) claudin-low mammary tumor cells. Cell proliferation and migration were assessed using BrdU incorporation and transwell migration across Matrigel coated inserts, respectively. miRNA sequencing and RNA sequencing were performed to explore miRNAs and mRNAs regulated by miR-200 re-expression while Enrichr-based pathway analysis was utilized to identify cellular functions modified by miR-200s. Results: Re-expression of the miR-200s in murine and human claudin-low mammary tumor cells partially restored an epithelial cell morphology and significantly inhibited proliferation and cell invasion in vitro. miRNA sequencing and mRNA sequencing revealed that re-expression of miR-200s altered the expression of other microRNAs and genes regulated by SUZ12 providing insight into the complexity of miR-200 function. SUZ12 is a member of the polycomb repressor complex 2 that suppresses gene expression through methylating histone H3 at lysine 27. Flow cytometry confirmed that re-expression of miR-200s increased histone H3 methylation at lysine 27. Conclusions: Re-expression of miR-200s in claudin-low mammary tumor cells alters cell morphology and reduces proliferation and invasion, an effect potentially mediated by SUZ12-regulated genes and other microRNAs. [ABSTRACT FROM AUTHOR]

Non‐coding RNAs play important roles in tumorigenesis and tumour progression. In previous screening, lncRNA‐LINC00659 (LINC00659) is highly expressed in gastric cancer; however, its role in gastric cancer has not been illustrated yet. In this study, the expression of LINC00659 was detected in cancer tissues and paracancerous tissues of patients with gastric cancer. As a result, LINC00659 expression was increased in gastric cancer tissues, which was closely associated with tumour stage and lymph node metastasis, but was not correlated with age, gender and tissue differentiation. Survival curve analysis showed that patients with low expression of LINC00659 harboured higher overall survival. In vitro, the level of LINC00659 was increased in gastric cancer cells. Afterwards, the expression of LINC00659 was down‐regulated in SGC‐7901 and BGC‐823 cells by plasmid‐mediated si‐LINC00659 transfection. Consequently, the cell invasion ability was weakened, the cell cycle was inhibited, and cell viability was also suppressed. Luciferase reporter gene assay and RNA pull‐down assay showed that LINC00659 could bind to the transcription factor SUZ12, indicating that SUZ12 was a regulatory gene of LINC00659. The overexpression of SUZ12 could resist the roles of si‐LINC00659. In this study, we found that LINC00659 was highly expressed in gastric cancer, which might be related to the regulation of cell proliferation and promotion of cell invasion. Transcription factor, SUZ12, was a regulator of LINC00659. Additionally, LINC00659 could regulate cell cycle and invasion of gastric cancer by promoting the expression of SUZ12. [ABSTRACT FROM AUTHOR]

Polycomb repressive complex 2 (PRC2) is an epigenetic regulator of gene expression that possesses histone methyltransferase activity. PRC2 trimethylates lysine 27 of histone H3 proteins (H3K27me3) as a chromatin modification associated with repressed transcription of genes frequently involved in cell proliferation or self-renewal. Loss-of-function mutations in the PRC2 core subunit SUZ12 have been identified in a variety of tumors, including malignant peripheral nerve sheath tumors (MPNSTs). To determine the consequences of SUZ12 loss in the pathogenesis of MPNST and other cancers, we used CRISPR-Cas9 to disrupt the open reading frame of each of two orthologous suz12 genes in zebrafish: suz12a and suz12b. We generated these knockout alleles in the germline of our previously described p53 (also known as tp53)- and nf1-deficient zebrafish model of MPNSTs. Loss of suz12 significantly accelerated the onset and increased the penetrance of MPNSTs compared to that in control zebrafish. Moreover, in suz12-deficient zebrafish, we detected additional types of tumors besides MPNSTs, including leukemia with histological characteristics of lymphoid malignancies, soft tissue sarcoma and pancreatic adenocarcinoma, which were not detected in p53/nf1-deficient control fish, and are also contained in the human spectrum of SUZ12-deficient malignancies identified in the AACR Genie database. The suz12-knockout tumors displayed reduced or abolished H3K27me3 epigenetic marks and upregulation of gene sets reported to be targeted by PRC2. Thus, these zebrafish lines with inactivation of suz12 in combination with loss of p53/nf1 provide a model of human MPNSTs and multiple other tumor types, which will be useful for mechanistic studies of molecular pathogenesis and targeted therapy with small molecule inhibitors.

Background: Neural tube defects (NTDs) are severe, common birth defects that result from failure of normal neural tube closure during early embryogenesis. Accumulating strong evidence indicates that genetic factors contribute to NTDs etiology, among them, HOX genes play a key role in neural tube closure. Although abnormal HOX gene expression can lead to NTDs, the underlying pathological mechanisms have not fully been understood. Method: We detected that H3K27me3 and expression of the Hox genes in a retinoic acid (RA) induced mouse NTDs model on E8.5, E9.5 and E10.5 using RNA-sequencing and chromatin immunoprecipitation sequencing assays. Furthermore, we quantified 10 Hox genes using NanoString nCounter in brain tissue of fetuses with 39 NTDs patients including anencephaly, spina bifida, hydrocephaly and encephalocele. Results: Here, our results showed differential expression in 26 genes with a > 20-fold change in the level of expression, including 10 upregulated Hox genes. RT-qPCR revealed that these 10 Hox genes were all upregulated in RA-induced mouse NTDs as well as RA-treated embryonic stem cells (ESCs). Using ChIP-seq assays, we demonstrate that a decrease in H3K27me3 level upregulates the expression of Hox cluster A–D in RA-induced mouse NTDs model on E10.5. Interestingly, RA treatment led to attenuation of H3K27me3 due to cooperate between UTX and Suz12, affecting Hox gene regulation. Further analysis, in human anencephaly cases, upregulation of 10 HOX genes was observed, along with aberrant levels of H3K27me3. Notably, HOXB4, HOXC4 and HOXD1 expression was negatively correlated with H3K27me3 levels. Conclusion: Our results indicate that abnormal HOX gene expression induced by aberrant H3K27me3 levels may be a risk factor for NTDs and highlight the need for further analysis of genome-wide epigenetic modification in NTDs. [ABSTRACT FROM AUTHOR]

The most aggressive of four medulloblastoma (MB) subgroups are cMyc-driven group 3 (G3) tumors, some of which overexpress EZH2, the histone H3K27 mono-, di-, and trimethylase of polycomb-repressive complex 2. Ezh2 has a context-dependent role in different cancers as an oncogene or tumor suppressor and retards tumor progression in a mouse model of G3 MB. Engineered deletions of Ezh2 in G3 MBs by gene editing nucleases accelerated tumorigenesis, whereas Ezh2 re-expression reversed attendant histone modifications and slowed tumor progression. Candidate oncogenic drivers suppressed by Ezh2 included Gfi1, a proto-oncogene frequently activated in human G3 MBs. Gfi1 disruption antagonized the tumor-promoting effects of Ezh2 loss; conversely, Gfi1 overexpression collaborated with Myc to bypass effects of Trp53 inactivation in driving MB progression in primary cerebellar neuronal progenitors. Although negative regulation of Gfi1 by Ezh2 may restrain MB development, Gfi1 activation can bypass these effects.

Numerous molecular processes conduct epigenetic regulation of protein transcription to maintain cell specification. In this review, we discuss molecular mechanisms of the Polycomb group of proteins and its enzymatic role in epigenetics. More specifically, we focus on the Polycomb repressive complex 2 (PRC2) and the effects of its repressive marker. We have compiled information regarding the biological structure and how that impacts the stability of the complex. In addition, we examined functions of the individual core proteins of PRC2 in relation to the accessory proteins that interact with the complex. Lastly, we discuss the implications of unregulated and downregulated PRC2 activity in Alzheimer's disease and cancer and possible methods of treatment related to PRC2 regulation. [ABSTRACT FROM AUTHOR]

SUZ12 is a core component of polycomb repressive complex 2 (PRC2) along with EZH2 and EED. Recently, germline mutations in the SUZ12, EZH2 and EED genes have been reported in Weaver syndrome (WS) or Weaver‐like syndrome, suggesting a functional link between PRC2 deficits and WS. However, only one case of a SUZ12 mutation presenting with Weaver‐like syndrome has been reported. Here, we report a missense and a frameshift mutation in SUZ12 (c.1797A>C; p.Gln599His and c.844_845del; p.Ala282Glnfs*7), both of which are novel, in two individuals. Their clinical features included postnatal overgrowth, increased bifrontal diameter, large ears, round face, horizontal chin crease and skeletal anomalies, but did not fulfill the WS diagnostic criteria. These data provide strong evidence that SUZ12 mutations cause Weaver‐like syndrome. [ABSTRACT FROM AUTHOR]

Abstract: The suppressor of zest 12 (SUZ12), one of the core polycomb repressive complex 2 (PRC2) components, has increasingly appreciated as a key mediator during human tumorigenesis. However, its expression pattern and oncogenic roles in head and neck squamous cell carcinoma (HNSCC) remain largely unexplored yet. Here, we sought to determine its expression pattern, clinicopathological significance and biological roles in HNSCC. Through data mining and interrogation from multiple publicly available databases, our bioinformatics analyses revealed that SUZ12 mRNA was significantly overexpressed in multiple HNSCC patient cohorts. Moreover, SUZ12 protein was markedly up‐regulated in primary HNSCC samples from our patient cohort as assessed by immunohistochemical staining and its overexpression significantly associated with cervical node metastasis and reduced overall and disease‐free survival. In the 4‐nitroquinoline 1‐oxide (4NQO)‐induced HNSCC mouse model, increased SUZ12 immunostaining was observed along with disease progression from epithelial hyperplasia to squamous cell carcinoma in tongue. Furthermore, shRNA‐mediated SUZ12 knock‐down significantly inhibited cell proliferation, migration and invasion in HNSCC cells, and resulted in compromised tumour growth in vivo. Collectively, our data reveal that SUZ12 might serve as a putative oncogene by promoting cell proliferation, migration and invasion, and also a novel biomarker with diagnostic and prognostic significance for HNSCC. [ABSTRACT FROM AUTHOR]

There are seven conserved CTCF binding domains in the herpes simplex virus 1 (HSV-1) genome. These binding sites individually flank the latency-associated transcript (LAT) and the immediate early (IE) gene regions, suggesting that CTCF insulators differentially control transcriptional domains in HSV-1 latency. In this work, we show that two CTCF binding motifs in HSV-1 display enhancer blocking in a celltype- specific manner. We found that CTCF binding to the latent HSV-1 genome was LAT dependent and that the quantity of bound CTCF was site specific. Following reactivation, CTCF eviction was dynamic, suggesting that each CTCF site was independently regulated. We explored whether CTCF sites recruit the polycomb-repressive complex 2 (PRC2) to establish repressive domains through a CTCF-Suz12 interaction and found that Suz12 colocalized to the CTCF insulators flanking the ICP0 and ICP4 regions and, conversely, was removed at early times postreactivation. Collectively, these data support the idea that CTCF sites in HSV-1 are independently regulated and may contribute to lytic-latent HSV-1 control in a site-specific manner. IMPORTANCE The role of chromatin insulators in DNA viruses is an area of interest. It has been shown in several beta- and gammaherpesviruses that insulators likely control the lytic transcriptional profile through protein recruitment and through the formation of three-dimensional (3D) chromatin loops. The ability of insulators to regulate alphaherpesviruses has been understudied to date. The alphaherpesvirus HSV-1 has seven conserved insulator binding motifs that flank regions of the genome known to contribute to the establishment of latency. Our work presented here contributes to the understanding of how insulators control transcription of HSV-1. [ABSTRACT FROM AUTHOR]

Objective: Increased expression of suppressor of zest 12 (SUZ12), a core component of the polycomb repressive complex 2, contributes to human tumorigenesis and associates with patient prognosis. In the present study, we sought to investigate the expression of SUZ12 and its clinicopathological significance in primary tongue squamous cell carcinoma (TSCC). Methods: The expression of SUZ12 protein was determined by immunohistochemistry in clinical samples from a retrospective cohort of 72 patients with primary TSCC who were treated at our institution from Jan. 2007 to Dec. 2013. The potential associations between SUZ12 abundance and multiple clinicopathological parameters were assessed by Chi square test. Moreover, the effect of SUZ12 expression on patients' survival was further estimated by Kaplan-Meier and Cox regression analyses. Results: Our immunohistochemical staining data revealed aberrant overexpression of SUZ12 in a large subset of TSCC as compared to normal tongue mucosa. Elevated SUZ12 was found to be significantly associated with cervical nodes metastasis (P = 0.0325) and reduced overall as well as disease-free survival (Log-rank test, P = 0.0225, 0.0179, respectively). Both univariate and multivariate Cox regression analysis identified the expression status of SUZ12 (low/ high) as an important independent prognostic factor for patients' survival. Conclusions: Our data reveal that aberrant SUZ12 overexpression is associated with cervical nodes metastasis and reduced survival in TSCC. These findings suggest that SUZ12 might play critical roles during tongue tumorigenesis and serve as a novel biomarker with diagnostic and prognostic significance. [ABSTRACT FROM AUTHOR]

Background: While Alzheimer's disease (AD) pathology is associated with altered brain structure, it is not clear whether gene expression changes mirror the onset and evolution of pathology in distinct brain regions. Deciphering the mechanisms which cause the differential manifestation of the disease across different regions has the potential to help early diagnosis., Objective: We aimed to identify common and unique endotypes and their regulation in tangle-free neurons in sporadic AD (SAD) across six brain regions: entorhinal cortex (EC), hippocampus (HC), medial temporal gyrus (MTG), posterior cingulate (PC), superior frontal gyrus (SFG), and visual cortex (VCX)., Methods: To decipher the states of tangle-free neurons across different brain regions in human subjects afflicted with AD, we performed analysis of the neural transcriptome. We explored changes in differential gene expression, functional and transcription factor target enrichment, and co-expression gene module detection analysis to discern disease-state transcriptomic variances and characterize endotypes. Additionally, we compared our results to tangled AD neuron microarray-based study and the Allen Brain Atlas., Results: We identified impaired neuron function in EC, MTG, PC, and VCX resulting from REST activation and reversal of mature neurons to a precursor-like state in EC, MTG, and SFG linked to SOX2 activation. Additionally, decreased neuron function and increased dedifferentiation were linked to the activation of SUZ12. Energetic deficit connected to NRF1 inactivation was found in HC, PC, and VCX., Conclusions: Our findings suggest that SAD manifestation varies in scale and severity in different brain regions. We identify endotypes, such as energetic shortfalls, impaired neuronal function, and dedifferentiation., Competing Interests: The authors have no conflict of interest to report., (© 2023 – The authors. Published by IOS Press.)

Background/Aims: SUZ12 and EZH2 are two main components of polycomb repressive complex 2 (PRC2) that is known to be of great importance in tumorigenesis. EZH2 has been reported to play a vital role in pathogenesis of human cancer. However, whether SUZ12 has equivalent roles in tumorigenesis has not been demonstrated. Here, we investigated a possible role of SUZ12 for the proliferation of gastric cancer cells. Methods: Western-blot analysis was used to detected the levels of SUZ12, H3K27me3, EZH2 and p27 in ten gastric cell lines. SUZ12 was depleted by RNA interference. Cell cycle was detected by flow cytometry. Luciferase assays was to analyze whether miR-200b directly regulate SUZ12. Results: We found that SUZ12 depletion mediated by RNA interference (RNAi) led to a reduction of gastric cell numbers and arrested the cell cycle at G1/S point. As an important G1/S phase inhibitory gene, p27 is re-induced to some extent by SUZ12 knockdown. Furthermore, we demonstrated that SUZ12 was directly downregulated by miR-200b. Conclusion: We provide evidence suggesting that SUZ12 may be a potential therapeutic target for gastric cancer.

This review focuses on the significance of deregulation of epigenetic mechanisms by the hepatitis B virus (HBV) X protein in hepatocarcinogenesis and HBV replication. Epigenetic mechanisms, DNA methylation, and specific histone modifications, e.g., trimethylation of H3 on lysine-27 or lysine-4, maintain ‘cellular memory’ by silencing expression of lineage-inducing factors in stem cells and conversely, of pluripotency factors in differentiated cells. The X protein has been reported to induce expression of DNA methyltransferases (DNMTs), likely promoting epigenetic changes during hepatocarcinogenesis. Furthermore, in cellular and animal models of X-mediated oncogenic transformation, protein levels of chromatin modifying proteins Suz12 and Znf198 are down-regulated. Suz12 is essential for the Polycomb Repressive Complex 2 (PRC2) mediating the repressive trimethylation of H3 on lysine-27 (H3K27me3). Znf198, stabilizes the LSD1-CoREST-HDAC complex that removes, via lysine demethylase1 (LSD1), the activating trimethylation of H3 on lysine-4 (H3K4me3). Down-regulation of Suz12 also occurs in liver tumors of woodchucks chronically infected by woodchuck hepatitis virus, an animal model recapitulating HBV-mediated hepatocarcinogenesis in humans. Significantly, subgroups of HBV-induced liver cancer re-express hepatoblast and fetal markers, and imprinted genes, suggesting hepatocyte reprogramming during oncogenic transformation. Lastly, down-regulation of Suz12 and Znf198 enhances HBV replication. Collectively, these observations suggest deregulation of epigenetic mechanisms by HBV X protein influences both the viral cycle and the host cell.