H3 Methylation Research Articles

IOX-1 suppresses metastasis of osteosarcoma by upregulating histone H3 lysine trimethylation

New therapeutic approaches are needed for metastatic osteosarcoma (OS), as survival rates remain low despite surgery and chemotherapy. Epigenetic changes, such as histone H3 methylation, play key roles in many cancers including OS, although the underlying mechanisms are not clear. In this study, human OS tissue and OS cell lines displayed lower levels of histone H3 lysine trimethylation compared with normal bone tissue and osteoblast cells. Treating OS cells with the histone lysine demethylase inhibitor 5-carboxy-8-hydroxyquinoline (IOX-1) dose-dependently increased histone H3 methylation and inhibited cellular migratory and invasive capabilities, suppressed matrix metalloproteinase expression, reversed epithelial-to-mesenchymal transition by increasing levels of epithelial markers E-cadherin and ZO-1 and decreasing the expression of mesenchymal markers N-cadherin, vimentin, and TWIST, and also reduced stemness properties. An analysis of cultivated MG63 cisplatin-resistant (MG63-CR) cells revealed lower histone H3 lysine trimethylation levels compared with levels in MG63 cells. Exposing MG63-CR cells to IOX-1 increased histone H3 trimethylation and ATP-binding cassette transporter expression, potentially sensitizing MG63-CR cells to cisplatin. In conclusion, our study suggests that histone H3 lysine trimethylation is associated with metastatic OS and that IOX-1 or other epigenetic modulators present promising strategies to inhibit metastatic OS progression.

Chemical inhibition of LSD1 leads to epithelial to mesenchymal transition in vitro of an oral squamous cell carcinoma OM-1 cell line via release from LSD1-dependent suppression of ZEB1

The epigenetic regulation for gene expression determines cell plasticity. Oral squamous cell carcinoma (SCC) exhibits bidirectional cell plasticity, i.e. epithelial differentiation and epithelial to mesenchymal transition (EMT). The epigenetic regulator LSD1 is a histone H3-specific demethylase to which chemical inhibitors for its activity had been developed as an anti-cancer therapeutics. The bidirectional plasticity of the oral SCC cell line OM-1 had been characterized, but it remained unclear how chemical LSD1 inhibitors affect cell plasticity. Here we reported an adverse effect against cancer therapeutics, which was EMT induction in vitro by the chemical LSD1 inhibitor. The LSD1 inhibitor caused EMT-TF ZEB1 in OM-1 to undergo EMT. Furthermore, an additional EMT-TF Snail-dependent partial EMT phenotype in OM-1 progressed to complete EMT in conjunction with LSD1 inhibitor-dependent ZEB1 induction. The promotor activity of ZEB1 was up-regulated under LSD1 inhibition. The regulatory chromatin regions of ZEB1 accumulated histone H3 methylation under the chemical inhibition of LSD1. The LSD1 inhibitor also upregulates epithelial gene expression in vitro; however, the bidirectional effect of LSD1 inhibitor should be considered in cancer therapeutics.

DOT-1.1 (DOT1L) deficiency in C. elegans leads to small RNA-dependent gene activation

Methylation of histone H3 at lysine 79 (H3K79) is conserved from yeast to humans and is accomplished by Dot1 (disruptor of telomeric silencing-1) methyltransferases. The C. elegans enzyme DOT-1.1 and its interacting partners are similar to the mammalian DOT1L (Dot1-like) complex. The C. elegans DOT-1.1 complex has been functionally connected to RNA interference. Specifically, we have previously shown that embryonic and larval lethality of dot-1.1 mutant worms deficient in H3K79 methylation was suppressed by mutations in the RNAi pathway genes responsible for generation (rde-4) and function (rde-1) of primary small interfering RNAs (siRNAs). This suggests that dot-1.1 mutant lethality is dependent on the enhanced production of some siRNAs. We have also found that this lethality is suppressed by a loss-of-function of CED-3, a conserved apoptotic protease. Here, we describe a comparison of gene expression and primary siRNA production changes between control and dot-1.1 deletion mutant embryos. We found that elevated antisense siRNA production occurred more often at upregulated than downregulated genes. Importantly, gene expression changes were dependent on RDE-4 in both instances. Moreover, the upregulated group, which is potentially activated by ectopic siRNAs, was enriched in protease-coding genes. Our findings are consistent with a model where in the absence of H3K79 methylation there is a small RNA-dependent activation of protease genes, which leads to embryonic and larval lethality. DOT1 enzymes’ conservation suggests that the interplay between H3K79 methylation and small RNA pathways may exist in higher organisms.

Chromatin Immunostaining of Plant Nuclei.

Recent evidence has demonstrated that specific epigenetic changes are also related to plant growth and development. Immunostaining enables the detection and characterization of chromatin modification, e.g., histone H4 acetylation (H4K5ac), histone H3 methylation (H3K4me2 and H3K9me2), and DNA methylation (5mC) with unique and specific patterns in plant tissues. Here we describe experimental procedures to determine the histone H3 methylation (H3K4me2 and H3K9me2) patterns in 3D-chromatin in whole roots tissue and 2D-chromatin in single nuclei in rice. To analyze both iron and salinity treatments, we show how to test for changes to the epigenetic chromatin landscape using heterochromatin (H3K9me2) and euchromatin (H3K4me) markers for chromatin immunostaining, especially in the proximal meristem region. To elucidate the epigenetic impact of environmental stress and external plant growth regulators, we demonstrate how to apply a combination of salinity, auxin, and abscisic acid treatments. The results of these experiments provide insights into the epigenetic landscape during rice root growth and development.

DNA methylation 6 mA and histone methylation involved in multi-/trans-generational reproductive effects in Caenorhabditis elegans induced by Atrazine

Atrazine (ATR), a widely used triazine herbicide, is an environmental endocrine disruptor that can cause health problems. However, whether there are multi/trans-generational reproductive impacts of ATR have not been studied. Therefore, in this study, Caenorhabditis elegans was used as a preferable model organism to identify the multi/trans-generational reproductive toxicity of ATR. Only parental C.elegans (P0) were exposed to different concentrations (0.0004–40 mg/L) for 48 h and the subsequent offspring (F1–F5) were grown under ATR-free conditions and ATR conditions.The results showed that ATR exposure during P0 decreased fecundity, including a reduction in fertilized eggs, oocytes, and ovulation rate, delayed gonadal development, and decreased the relative area of gonad arm and germ cell number. Furthermore, continuous ATR exposure (P0–F5) causes a significant increase in reproductive toxicity in subsequent generations, although no significant toxicity occurred in the P0 generation after exposure to environmental-related concentrations, suggesting that ATR exposure might have cumulative effects. Likewise, parental exposure to ATR caused transgenerational toxicity impairments. Interestingly, only reproductive toxicity, not development toxicity, was transmitted to several generations (F1–F4), and the F2 generation showed the most notable changes. QRT-PCR results showed that genes expression related to DNA methylation 6 mA (damt-1, nmad-1) and histone H3 methylation (mes-4, met-2, set-25, set-2, and utx-1) can also be passed on to offspring. The function of H3K4 and H3K9 methylation were explored by using loss-of-function mutants for set-2, set-25, and met-2. Transmissible reproductive toxicity was absent in met-2(n4256), set-2(ok952), and set-25(n5021) mutants, which suggests that the histone methyltransferases H3K4 and H3K9 activity are indispensable for the transgenerational effect of ATR. Finally, the downstream genes of DNA methylation and histone H3 methylation were determined. ATR upregulated the expression of ZC317.7, hsp-6, and hsp-60. Mitochondrial stress in parental generation dependent transcription 6 mA modifiers may establish these epigenetic marks in progeny.

RINGs, DUBs and Abnormal Brain Growth-Histone H2A Ubiquitination in Brain Development and Disease.

During mammalian neurodevelopment, signaling pathways converge upon transcription factors (TFs) to establish appropriate gene expression programmes leading to the production of distinct neural and glial cell types. This process is partially regulated by the dynamic modulation of chromatin states by epigenetic systems, including the polycomb group (PcG) family of co-repressors. PcG proteins form multi-subunit assemblies that sub-divide into distinct, yet functionally related families. Polycomb repressive complexes 1 and 2 (PRC1 and 2) modify the chemical properties of chromatin by covalently modifying histone tails via H2A ubiquitination (H2AK119ub1) and H3 methylation, respectively. In contrast to the PRCs, the Polycomb repressive deubiquitinase (PR-DUB) complex removes H2AK119ub1 from chromatin through the action of the C-terminal hydrolase BAP1. Genetic screening has identified several PcG mutations that are causally associated with a range of congenital neuropathologies associated with both localised and/or systemic growth abnormalities. As PRC1 and PR-DUB hold opposing functions to control H2AK119ub1 levels across the genome, it is plausible that such neurodevelopmental disorders arise through a common mechanism. In this review, we will focus on advancements regarding the composition and opposing molecular functions of mammalian PRC1 and PR-DUB, and explore how their dysfunction contributes to the emergence of neurodevelopmental disorders.

Epigenetic regulation for delaying tomato fruit ripening through histone modification by specific sound wave treatment

Controlling fruit ripening is crucial for maintaining its quality during delivery. A specific sound wave treatment to delay fruit ripening without genetic modifications has been identified as an effective method in tomatoes. However, the molecular mechanisms of the sound wave-triggered suppression of fruit ripening remain largely unknown. In this study, we demonstrated that sound waves influence histone modifications, particularly at ethylene biosynthesis-related genetic loci, inhibiting transcription. Sound waves reduced histone modifications involved in transcriptional activation but increased repressive histone modifications at the RIN, NOR, and TAGL1 genes, which are positive regulators of fruit ripening. Similar epigenetic events have also been observed in genes encoding ethylene biosynthesis enzymes. Sound wave treatment upregulated the expression of histone modification enzyme genes involved in H3 methylation and deacetylation but downregulated those involved in H3 demethylation and acetylation. In addition, histone-modifying enzymes may directly associate with promoters of RIN, NOR, and TAGL1 genes and indirectly associate with promoters of ethylene biosynthesis enzyme genes through physical interactions with transcription factors. Our findings provide the basis for the practical use of sound waves to delay fruit ripening.

Abstract B031: PRC2 inhibitor suppresses angiogenesis in Hepatocellular carcinoma (HCC) by up-regulation of anti-angiogenic factors vasohibin1 (VASH1) and tissue inhibitor of metalloproteinases 3 (TIMP-3)

Abstract Tumor-associated angiogenesis plays a crucial role in the progression of tumor, especially in highly vascularized cancer, such as Liver hepatocellular carcinoma (LIHC), ovarian cancer, lung cancer, human head and neck cancers. Clinical research has shown that LIHC cells upregulate expression of vascular endothelial growth factor A (VEGFA), and induce proliferation and migration of epithelial cells under hypoxia condition, however, the mechanism of angiogenesis has not been completely elucidated in LIHC, especially in epigenetic regulation level. Polycomb repressive complex 2 (PRC2) is a multi-subunit protein complex that catalyzes the methylation of histone H3 at lysine 27, Enhancer of Zeste homolog 2 (EZH2) is the catalytic subunit, while embryonic ectoderm development (EED) recognizes H3K27me3 and enhance the catalytic activity of EZH2. A recent study suggests PRC2 promote angiogenesis in human ovarian carcinoma, while the detailed mechanism this process has not been illustrated. In this paper, we show BR1763, a potent, selective and orally bioavailable small-molecule inhibitor of EED, inhibits PRC2 activity, promote expression of vasohibin1 (VASH1) and tissue inhibitor of metalloproteinases 3 (TIMP3) in certain Hepatocellular Carcinoma (HCC) cells, and induces tumor growth inhibition by suppression of tumor-associated angiogenesis in vivo. Citation Format: Hailong Zhang. PRC2 inhibitor suppresses angiogenesis in Hepatocellular carcinoma (HCC) by up-regulation of anti-angiogenic factors vasohibin1 (VASH1) and tissue inhibitor of metalloproteinases 3 (TIMP-3). [abstract]. In: Proceedings of the AACR Special Conference: Cancer Epigenomics; 2022 Oct 6-8; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_2):Abstract nr B031.

KDM1A drives hepatoblastoma progression by activating the Wnt/β-catenin pathway through inhibition of DKK3 transcription

This study is to explore the mechanism of KDM1A-regulated hepatoblastoma (HB) development. Cancerous and paracancer tissues of 30 HB patients were collected for detection of KDM1A and DKK3 expression. HuH-6 and HepG2 cells were subjected to assays of cellular activities after treatment with sh-KDM1A, sh-DKK3, and/or XAV-939 (an inhibitor of the Wnt/β-catenin pathway). Chromatin immunoprecipitation was used to determine the interaction of KDM1A with DKK3. Nude mice were injected with HuH-6 cells in which KDM1A was knocked down. KDM1A was highly expressed and DKK3 was lowly expressed in HB patients. Knockdown of KDM1A reduced the proliferative and invasive capabilities of HepG2 and HuH-6 cells and accelerated the cell apoptosis; these influences were nullified by knockdown of DKK3. KDM1A inhibited DKK3 transcription by reducing H3 methylation. XAV-939 treatment inhibited the development of HepG2 and HuH-6 cells in which KDM1A and DKK3 were both knocked down. Knockdown of KDM1A reduced the tumor mass, inactivated the Wnt/β-catenin signaling, and increased the expression of DKK3 in nude mice. KDM1A stimulates HB development by activating the Wnt/β-catenin pathway through inhibition of DKK3 transcription.

Epigenetic mechanisms of Strip2 in differentiation of pluripotent stem cells

Significant evidence points to Strip2 being a key regulator of the differentiation processes of pluripotent embryonic stem cells. However, Strip2 mediated epigenetic regulation of embryonic differentiation and development is quite unknown. Here, we identified several interaction partners of Strip2, importantly the co-repressor molecular protein complex nucleosome remodeling deacetylase/Tripartite motif-containing 28/Histone deacetylases/Histone-lysine N-methyltransferase SETDB1 (NuRD/TRIM28/HDACs/SETDB1) histone methyltransferase, which is primarily involved in regulation of the pluripotency of embryonic stem cells and its differentiation. The complex is normally activated by binding of Krueppel-associated box zinc-finger proteins (KRAB-ZFPs) to specific DNA motifs, causing methylation of H3 to Lysin-9 residues (H3K9). Our data showed that Strip2 binds to a DNA motif (20 base pairs), like the KRAB-ZFPs. We establish that Strip2 is an epigenetic regulator of pluripotency and differentiation by modulating DNA KRAB-ZFPs as well as the NuRD/TRIM28/HDACs/SETDB1 histone methyltransferase complex.

Identification of alternative transcripts of NSD1 gene in Sotos Syndrome patients and healthy subjects

NSD1 gene (Nuclear Receptor Binding SET Domain Protein 1) encodes a methyltransferase that plays an important role in embryonic development. NSD1 is implicated in the transcription and methylation of histone H3 at lysine 36 (H3-K36), but the molecular mechanisms involved in these processes remain largely unknown. Pathogenic variants of NSD1 gene lead to Sotos syndrome, and have also been detected in some type of cancers, such as acute myeloid leukemia.In this study we have investigated NSD1 mRNA expression in fibroblast cell lines obtained from 14 Sotos patients and from 8 healthy controls. In addition to the expected NSD1 canonical transcript (isoform 1), we identified two additional, not yet reported, short NSD1 mRNA isoforms: NSD1 Δ5Δ7 (isoform 2) and NSD1 Δ19-23 (isoform 3), both in healthy subjects and in Sotos patients. We also show that NSD1 mutations in patients can be associated with a decreased level of NSD1 mRNA, as expected. Moreover, one patient, bearing the NSD1 variant c.6010-10G > A, expressed an additional shorter transcript derived from an aberrant splicing event.These results may provide a basis to elucidate the impact of different NSD1 pathogenic variants on the heterogeneity of phenotype associated with Sotos syndrome.

Deficiency of p53 Causes the Inadequate Expression of miR-1246 in B Cells of Systemic Lupus Erythematosus.

Underexpression of p53 is considered the leading cause of the decreased miR-1246 expression in B cells of systemic lupus erythematosus (SLE) patients, yet the exact mechanism of action still remains unclear. To further explore the molecular mechanism of p53 upregulating miR-1246 expression, we targeted the methylation and acetylation of histone H3 in the miR-1246 promoter region of SLE B cells. We found that increased histone H3 trimethylation at Lys27 (H3K27me3) and decreased histone H3 acetylation at Lys9 and Lys14 (H3K9/K14ac) in the miR-1246 promoter region are essential for the low expression of miR-1246 in SLE B cells. p53 can promote miR-1246 transcription by recruiting Jumonji domain-containing protein 3 (JMJD3), E1A-binding protein p300 (EP300), and CREB-binding protein (CBP) to bind to the miR-1246 promoter, downregulating H3K27me3 and upregulating H3K9/K14ac. Furthermore, early B cell factor 1 (EBF1), CD40, CD38, and X box binding protein-1 (XBP-1) expression levels in SLE B cells transfected with p53 expression plasmid were significantly decreased, whereas autoantibody IgG production in autologous CD4+ T cells cocultured with overexpressed p53 SLE B cells was reduced. Collectively, our data suggest that the reduction of p53 decreases miR-1246 expression via upregulation of H3K27me3 and downregulation of H3K9/14ac, which in turn results in SLE B cell hyperactivity.

Expanding the Genotype and Phenotype of SETD5-Related Neurodevelopmental Syndrome

Su(var)3-9, Enhancer of Zeste, and Trithorax Domain Containing 5 (SETD5) gene, located on chromosome 3q3.25, has 49 exons and codes a 1442-amino acid protein belonging to the SET methyltransferase family.1 This protein catalyzes methylation of histone H3 and H4 lysine residues.2 Pathogenic variants in SETD5 are known to result in intellectual disability.3,4 Other reported manifestations of SETD5-related neurodevelopmental syndrome include autism, stuttering, brachycephaly, low-set ears, synophrys, ptosis, depressed nasal bridge, thin upper lip, micrognathia, postaxial polydactyly, leg-length discrepancy, feeding difficulties, congenital heart defects, skeletal issues, gastrointestinal and genitourinary malformations, and behavioral difficulties.

Bromoacetic acid impairs mouse oocyte in vitro maturation through affecting cytoskeleton architecture and epigenetic modification

As a major public health achievement, disinfection of drinking water significantly decreases outbreaks of waterborne disease, but produces drinking water disinfection by-products (DBPs) unfortunately. The haloacetic acids (HAAs) including bromoacetic acid (BAA), the second major class of DBPs, are considered as a global public health concern. BAA has been identified as cytotoxic, genotoxic, mutagenic, carcinogenic, and teratogenic in somatic cells. However, the toxic effects of BAA on oocyte maturation remain obscure. Herein, we documented that exposure to BAA compromised mouse oocyte maturation in vitro, causing blocked polar body extrusion (PBE). Meiotic progression analysis demonstrated that exposure to BAA induced the activated spindle assembly checkpoint (SAC) mediated metaphase I (MI) arrest in oocytes. Further study revealed that exposure to BAA resulted in the hyperacetylation of α-tubulin, disrupting spindle assembly and chromosome alignment, which is responsible for the activation of SAC. Besides, the organization of actin, the other major component of cytoskeleton in oocytes, was disturbed after BAA exposure. In addition, exposure to BAA altered the status of histone H3 methylation and 5 mC, indicative of the damaged epigenetic modifications. Moreover, we found that exposure to BAA induced DNA damage in a dose-dependent manner in oocytes. Collectively, our study evidenced that exposure to BAA intervened mouse oocyte maturation via disrupting cytoskeletal dynamics, damaging epigenetic modifications and inducing accumulation of DNA damage.

KMT2B-dependent RFK transcription activates the TNF-α/NOX2 pathway and enhances ferroptosis caused by myocardial ischemia-reperfusion

Epigenetic regulation such as histone modification is implicated in the pathogenesis of myocardial ischemia/reperfusion injury (MIRI). Lysine-specific methyltransferase 2B (KMT2B) is a histone H3 lysine 4 (H3K4) methyltransferase. This study aims at exploring the role of KMT2B-mediated histone modification in MIRI. Peripheral blood samples were collected from 30 patients with acute myocardial infarction (AMI) and 30 healthy volunteers for analyses of the expression levels of KMT2B, riboflavin kinase (RFK), tumor necrosis factor (TNF)-α, and NADPH oxidase 2 (NOX2). H9C2 cardiomyocytes and Sprague-Dawley rats were utilized for developing in vitro and in vivo models. To evaluate the effects of the aforementioned molecules on cellular damage and MIRI, short hairpin RNAs or overexpression plasmids were introduced into cardiomyocytes for gene silencing or overexpression and also, they were packaged into adenovirus vectors for in vivo interventions. Immunoprecipitation assays were conducted to assess the interactions between KMT2B and RFK and among RFK, NOX2 sub-unit p22phox, and TNF receptor 1-associated death domain protein. KMT2B, RFK, TNF-α, and NOX2 were notably upregulated in AMI patients. KMT2B knockdown resulted in considerably attenuated cell apoptosis and reduced myocardial infarct area. Additionally, the release of pro-inflammatory proteins and ferroptosis were suppressed. Furthermore, KMT2B could promote RFK gene transcription by upregulating H3 methylation levels and consequently activate the TNF-α/NOX2 axis, which was the possible mechanism underlying the role of KMT2B in MIRI. KMT2B motivates MIRI-induced cellular injury and ferroptosis by inducing RFK transcription and mediating the TNF-α/NOX2 axis.

Polycomb Directed Cell Fate Decisions in Development and Cancer.

The polycomb group (PcG) proteins are a subset of transcription regulators highly conserved throughout evolution. Their principal role is to epigenetically modify chromatin landscapes and control the expression of master transcriptional programs to determine cellular identity. The two mayor PcG protein complexes that have been identified in mammals to date are Polycomb Repressive Complex 1 (PRC1) and 2 (PRC2). These protein complexes selectively repress gene expression via the induction of covalent post-translational histone modifications, promoting chromatin structure stabilization. PRC2 catalyzes the histone H3 methylation at lysine 27 (H3K27me1/2/3), inducing heterochromatin structures. This activity is controlled by the formation of a multi-subunit complex, which includes enhancer of zeste (EZH2), embryonic ectoderm development protein (EED), and suppressor of zeste 12 (SUZ12). This review will summarize the latest insights into how PRC2 in mammalian cells regulates transcription to orchestrate the temporal and tissue-specific expression of genes to determine cell identity and cell-fate decisions. We will specifically describe how PRC2 dysregulation in different cell types can promote phenotypic plasticity and/or non-mutational epigenetic reprogramming, inducing the development of highly aggressive epithelial neuroendocrine carcinomas, including prostate, small cell lung, and Merkel cell cancer. With this, EZH2 has emerged as an important actionable therapeutic target in such cancers.

Distinct histone H3 modification profiles correlate with aggressive characteristics of salivary gland neoplasms

Post-translational modification of histones is the crucial event that affect many tumor-specific traits. A diverse type of histone modifications had been reported in different cancers with prognostic implications. This study aimed to examine the degree of histone H3 modifications in salivary gland neoplasms and their associations with tumor pathologic characteristics and proliferative activity. The expression of H3K9Ac, H3K18Ac, H3K9Me3 and Ki-67 in 70 specimens of salivary gland neoplasms, consisting of 30 mucoepidermoid carcinoma (MEC), 20 adenoid cystic carcinoma (ACC) and 20 pleomorphic adenoma (PA), were investigated immunohistochemically. The immunohistochemical scoring of 3 histone modification types and Ki-67 labeling index were determined. Overall, MEC demonstrated elevated H3K9Ac level compared with benign PA. Increased H3K9Me3 in MEC was positively correlated with small nest invasion at tumor front, advanced pathologic grade, and elevated proliferative index. In addition, the significant upregulation of all 3 types of histone H3 modification was noted in solid subtype of ACC and associated with increased cell proliferation. This study indicates that salivary gland neoplasms differentially acquire distinct patterns of histone H3 modification, which impact prognostically relevant cancer phenotypes. The hyperacetylation and methylation of histone H3 could be underpinning the prognostically worsen solid type of ACC, and the trimethylation of H3K9 may be involved in aggressive characteristics of MEC.

1258P HJM-353: A potent, selective and orally bioavailable EED inhibitor with robust anti-tumor activities

Polycomb Repressive Complex 2 (PRC2), a multimeric complex that catalyzes the methylation of histone H3 at lysine 27 with core subunits EZH2, EED and SUZ12, functions as an epigenetic modulator in regulating cell proliferation and development. Dysregulation of the PRC2 complex is implicated in hematological and solid malignancies and shown to correlate with poor prognosis in cancers. Recently EZH2 inhibitor Tazemetostat has been approved by FDA for the treatment of advanced epithelioid sarcoma and follicular lymphoma. However, acquired resistant mutations in EZH2 and complementary activation of EZH1 might impair the effectiveness of this class of PRC2 inhibitors. Targeting the allosteric subunit EED represents a new strategy to fully inhibit PRC2 activity and address the limitations of EZH2 inhibition. Herein, we report HJM-353 as an efficacious EED inhibitor for cancer therapy. In vitro activities of HJM-353 were assessed by CTG assay and Western blot in EZH2 mutant human cell lines.In vivo anti-tumor activities of HJM-353 were evaluated in DLBCL and gastric cancer xenograft models.Pharmacokinetic/pharmacodynamics correlation of HJM-353 was determined by LC-MS/MS, Western blot and Q-PCR. HJM-353 effectively reduced H3K27me3 level and inhibited cell proliferation with an IC50 of 33.8 nM in WSU-DLCL2 cells. It displayed favorable PK properties and induced complete tumor regression in KARPAS-422 derived DLBCL xenograft model. Plasma concentration of HJM-353 correlated with the inhibition of H3K27me3 and upregulation of PRC2 target genes in tumors, indicating a clear PK/PD relationship in the xenografts. In addition, HJM-353 caused tumor stasis as MAK683 did in a xKATO-III gastric xenograft model. In summary, HJM-353 is a potent, selective and orally bioavailable EED inhibitor with robust anti-tumor activities. We are developing HJM-353 for the treatment of hematological malignancies and solid tumors and expect to file an IND in the second half of 2022.

Adipocyte-mediated epigenomic instability in human T-ALL cells is cytotoxic and phenocopied by epigenetic-modifying drugs.

The world’s population with obesity is reaching pandemic levels. If current trends continue, it is predicted that there will be 1.5 billion people with obesity by 2030. This projection is alarming due to the association of obesity with numerous diseases including cancer, with recent studies demonstrating a positive association with acute myeloid leukemia (AML) and B cell acute lymphoblastic leukemia (B-ALL). Interestingly, several epidemiological studies suggest the converse relationship may exist in patients with T cell acute lymphoblastic leukemia (T-ALL). To determine the relationship between obesity and T-ALL development, we employed the diet-induced obesity (DIO) murine model and cultured human T-ALL cells in adipocyte-conditioned media (ACM), bone marrow stromal cell-conditioned media, stromal conditioned media (SCM), and unconditioned media to determine the functional impact of increased adiposity on leukemia progression. Whereas only 20% of lean mice transplanted with T-ALL cells survived longer than 3 months post-inoculation, 50%–80% of obese mice with leukemia survived over this same period. Furthermore, culturing human T-ALL cells in ACM resulted in increased histone H3 acetylation (K9/K14/K18/K23/K27) and methylation (K4me3 and K27me3) posttranslational modifications (PTMs), which preceded accelerated cell cycle progression, DNA damage, and cell death. Adipocyte-mediated epigenetic changes in human T-ALL cells were recapitulated with the H3K27 demethylase inhibitor GSK-J4 and the pan-HDAC inhibitor vorinostat. These drugs were also highly cytotoxic to human T-ALL cells at low micromolar concentrations. In summary, our data support epidemiological studies demonstrating that adiposity suppresses T-ALL pathogenesis. We present data demonstrating that T-ALL cell death in adipose-rich microenvironments is induced by epigenetic modifications, which are not tolerated by leukemia cells. Similarly, GSK-J4 and vorinostat treatment induced epigenomic instability and cytotoxicity profiles that phenocopied the responses of human T-ALL cells to ACM, which provides additional support for the use of epigenetic modifying drugs as a treatment option for T-ALL.

The Role of Histone H3 Methylation in Acute Kidney Injury.

Acute kidney injury (AKI) is a clinical syndrome in which kidney function declines sharply due to various reasons. Although the morbidity and mortality of AKI are high, the mechanism of occurrence and development of AKI has not been fully elucidated, and precise prevention and treatment measures are lacking. Epigenetics is a branch of genetics that provides a new perspective to explore the pathophysiology of AKI and renal repair. A large amount of literature shows that the methylation mechanism of H3 in histones is closely related to the development of kidney diseases. The sorting out of histone H3 methylation mechanism in AKI and kidney repair can help understand the pathophysiological process of the disease more deeply. It may also provide new ideas for diagnosing and treating of the disease.