Triggering "signal-on" photoelectrochemical responses by heterojunction transition for selective detection of copper(II) based on Pd/MoS2@g-C3N4 nanocomposites.

Controlling the concentration of copper(II) in aquatic systems is of importance for human health. Numerous traditional technologies to detect Cu2+ may encounter with limitations, such as high signal background and complicated operation. Herein, a highly selective photoelectrochemical (PEC) sensor is proposed for the "signal-on" detection of Cu2+ employing g-C3N4 nanosheets with MoS2 and Pd quantum dots deposited (Pd/MoS2@g-C3N4). Pd/MoS2@g-C3N4 could present the enhanced photocurrents of specific responses to Cu2+ under light irradiation. MoS2 quantum dots on the sensor are agglomerated into MoS2 bulk during sensing Cu2+, forming an efficient Z-scheme heterojunction. The heterojunction transition induced photoelectrons transferring from the bulk MoS2 to g-C3N4, resulting in "signal-on" PEC responses. Such Z-scheme heterojunction has conquered the traditional heterojunction towards "signal-on" mechanism, that was further verified by band structure measurements and DMPO spin trapping ESR analysis. Photocurrent intensities increased gradually with the addition of incremental Cu2+ concentrations, achieving a detection limit of 0.21 µM and a broad linear interval range from 1 µM to 1 mM with high selectivity and stability. This work may open a new door towards the in situ construction of g-C3N4-based Z-scheme heterojunctions for the signal-on PEC sensing platform, providing wide applications in environmental monitoring and food safety.

Deciphering the functional landscape of phosphosites with deep neural network.

Current biochemical approaches have only identified the most well-characterized kinases for a tiny fraction of the phosphoproteome, and the functional assignments of phosphosites are almost negligible. Herein, we analyze the substrate preference catalyzed by a specific kinase and present a novel integrated deep neural network model named FuncPhos-SEQ for functional assignment of human proteome-level phosphosites. FuncPhos-SEQ incorporates phosphosite motif information from a protein sequence using multiple convolutional neural network (CNN) channels and network features from protein-protein interactions (PPIs) using network embedding and deep neural network (DNN) channels. These concatenated features are jointly fed into a heterogeneous feature network to prioritize functional phosphosites. Combined with a series of in vitro and cellular biochemical assays, we confirm that NADK-S48/50 phosphorylation could activate its enzymatic activity. In addition, ERK1/2 are discovered as the primary kinases responsible for NADK-S48/50 phosphorylation. Moreover, FuncPhos-SEQ is developed as an online server.

The discovery of a non-competitive GOT1 inhibitor, hydralazine hydrochloride, via a coupling reaction-based high-throughput screening assay.

Glutamate oxaloacetate transaminase 1 (GOT1) plays a key role in aberrant glutamine metabolism. GOT1 suppression can arrest tumor growth and prevent the development of cancer, indicating GOT1 as a potential anticancer target. Reported GOT1 inhibitors, on the other hand, are quite restricted. Here, we developed and optimized a coupling reaction-based high-throughput screening assay for the discovery of GOT1 inhibitors. By using this screening assay, we found that the cardiovascular drug hydralazine hydrochloride inhibited GOT1 catalytic activity, with an IC50 of 26.62 ± 7.45 µM, in a non-competitive and partial-reversible manner. In addition, we determined the binding affinity of hydralazine hydrochloride to GOT1, with a Kd of 16.54 ± 8.59 µM, using a microscale thermophoresis assay. According to structure-activity relationship analysis, the inhibitory activity of hydralazine hydrochloride is mainly derived from its hydrazine group. Furthermore, it inhibits the proliferation of cancer cells MCF-7 and MDA-MB-468 with a slight inhibitory effect compared to other tested cancer cells, highlighting GOT1 as a promising therapeutic target for the treatment of breast cancer.

Targeting the RT loop of Src SH3 in Platelets Prevents Thrombosis without Compromising Hemostasis.

Conventional antiplatelet agents indiscriminately inhibit both thrombosis and hemostasis, and the increased bleeding risk thus hampers their use at more aggressive dosages to achieve adequate effect. Blocking integrin αIIbß3 outside-in signaling by separating the ß3/Src interaction, yet to be proven in vivo, may nonetheless resolve this dilemma. Identification of a specific druggable target for this strategy remains a fundamental challenge as Src SH3 is known to be responsible for binding to not only integrin ß3 but also the proteins containing the PXXP motif. In vitro and in vivo mutational analyses show that the residues, especially E97, in the RT loop of Src SH3 are critical for interacting with ß3. DCDBS84, a small molecule resulting from structure-based virtual screening, is structurally validated to be directed toward the projected target. It specifically disrupts ß3/Src interaction without affecting canonical PXXP binding and thus inhibits the outside-in signaling-regulated platelet functions. Treatment of mice with DCDBS84 causes a profound inhibition of thrombosis, equivalent to that induced by extremely high doses of αIIbß3 antagonist, but does not compromise primary hemostasis. Specific targets are revealed for a preferential inhibition of thrombosis that may lead to new classes of potent antithrombotics without hemorrhagic side effects.

Structure-Guided Development of Small-Molecule PRC2 Inhibitors Targeting EZH2-EED Interaction.

Disruption of EZH2-embryonic ectoderm development (EED) protein-protein interaction (PPI) is a new promising cancer therapeutic strategy. We have previously reported the discovery of astemizole, a small-molecule inhibitor targeting the EZH2-EED PPI. Herein, we report the cocrystal structure of EED in complex with astemizole at 2.15 Å. The structure elucidates the detailed binding mode of astemizole to EED and provides a structure-guided design for the discovery of a novel EZH2-EED interaction inhibitor, DC-PRC2in-01, with an affinity Kd of 4.56 µM. DC-PRC2in-01 destabilizes the PRC2 complex, thereby leading to the degradation of PRC2 core proteins and the decrease of global H3K27me3 levels in cancer cells. The proliferation of PRC2-driven lymphomas cells is effectively inhibited, and the cell cycle is arrested in the G0/G1 phase. Together, these data demonstrate that DC-PRC2in-01 could be an effective chemical probe for investigating the PRC2-related physiology and pathology and providing a promising chemical scaffold for further development.

Integrin ß3 Deficiency Results in Hypertriglyceridemia via Disrupting LPL (Lipoprotein Lipase) Secretion.

OBJECTIVE: Integrin ß3 is implicated in numerous biological processes such as its relevance to blood triglyceride, yet whether ß3 deficiency affects this metabolic process remains unknown. Approach and Results: We showed that the Chinese patients with ß3-deficient Glanzmann thrombasthenia had a 2-fold higher serum triglyceride level together with a lower serum LPL (lipoprotein lipase) level than those with an αIIb deficiency or healthy subjects. The ß3 knockout mice recapitulated these phenotypic features. The elevated plasma triglyceride level was due to impaired LPL-mediated triglyceride clearance caused by a disrupted LPL secretion. Further analysis revealed that ß3 directly bound LPL via a juxtamembrane TIH (threonine isoleucine histidine)720-722 motif in its cytoplasmic domain and functioned as an adaptor protein by interacting with LPL and PKD (protein kinase D) to form the PKD/ß3/LPL complex that is required for ß3-mediated LPL secretion. Furthermore, the impaired triglyceride clearance in ß3 knockout mice could be corrected by adeno-associated virus serotype 9 (AAV9)-mediated delivery of wild-type but not TIH720-722-mutated ß3 genes. CONCLUSIONS: This study reveals a hypertriglyceridemia in both ß3-deficient Chinese patients and mice and provides novel insights into the molecular mechanisms of the significant roles of ß3 in LPL secretion and triglyceride metabolism, drawing attention to the metabolic consequences in patients with ß3-deficient Glanzmann thrombasthenia.

A Sphingosine-1-Phosphate Modulator Ameliorates Polycystic Kidney Disease in Han:SPRD Rats.

BACKGROUND: Inflammation plays an important role in polycystic kidney disease (PKD). Cordyceps sinensis, a prized -Chinese medicinal herb, exerts anti-tumor, anti-inflammatory and anti-metastatic effects and benefits patients with kidney diseases. The aim of this study was to test the efficacy of FTY720, an immunosuppressant derived from C. sinensis, in a rat cystic kidney disease model, and explore its underlining mechanism. METHODS: Male wild type and Cy/+ Han:SPRD rats were treated with FTY720 at 3 and 10 mg/kg/day for 5 weeks and 12 weeks by gavage. Blood and kidney were collected for functional, morphological, RNA, and protein analysis. RESULTS: Inflammation is activated in Cy/+ Han:SPRD rats. Inflammatory cytokines including interleukin 6 and tumor necrosis factor alpha were upregulated and inflammation-related pathways were activated, such as nuclear factor κB and signal transducer and activator of transcription 3 (STAT3) pathways. Furthermore, the bioactive sphingolipid mediator sphingosine-1-phosphate (S1P), a regulator of inflammation, was accumulated in the Cy/+ Han:SPRD rats. FTY720 significantly reduced cyst growth and delayed disease progression by reducing the accumulation of S1P, thereby inhibiting inflammatory responses. CONCLUSION: FTY720 treatment reduced the expression of inflammatory cytokines and attenuated the activation of NK-κB and STAT3 pathways in Cy/+ Han:SPRD rats. It suggests that FTY720 may serve as a therapeutic agent for clinical autosomal dominant PKD treatment.

Licochalcone A suppresses the proliferation of sarcoma HT-1080 cells, as a selective R132C mutant IDH1 inhibitor.

IDH1 mutations are closely related to the development and progression of various human cancers, such as glioblastoma, sarcoma, and acute myeloid leukemia. By screening dozens of reported natural compounds using both wild-type and mutant IDH1 enzymatic assays, we discovered Licochalcone A is a selective inhibitor to the R132C-mutant IDH1 with an IC50 value of 5.176 µM, and inhibits the proliferation of sarcoma HT-1080 cells with an IC50 value of 10.75 µM. Suggested by the molecular docking results, Licochalcone A might occupy the allosteric pocket between the two monomers of IDH1 homodimer, and the R132H mutation was unfavorable for the binding of Licochalcone A with the IDH1 protein, as compared to the R132C mutation. Revealed by the RNA-Seq data analysis, the Cell Cycle pathway was the most over-represented pathway for HT-1080 cells treated with Licochalcone A. Consistent with these results, Licochalcone A induced apoptosis and cell cycle arrest of HT-1080 cells, while it showed minimal effect against the proliferation of normal RCTEC cells. The discovery of Licochalcone A as a mutation-selective IDH1 inhibitor can serve as a promising starting point for the development of mutation-selective anti-tumor lead compounds targeting IDH1.

Discovery of DC_H31 as potential mutant IDH1 inhibitor through NADPH-based high throughput screening.

IDH1 mutations are early events in the development of IDH-mutant gliomas and leukemias and are associated with various regulation of molecular process. Mutations of active site in IDH1 could lead to high levels of 2-HG and the suppression of cellular differentiation, while these changes can be reversed by molecule inhibitors target mutant IDH1. Here, through in-house developed enzymatic assay-based high throughput screening platform, we discovered DC_H31 as a novel IDH1-R132H/C inhibitor, with the IC50 value of 0.41 µmol/L and 2.7 µmol/L respectively. In addition, saturable SPR binding assay indicated that DC_H31 bound to IDH1-R132H/C due to specific interaction. Further computational docking studies and structure-activity relationship (SAR) suggest that DC_H31 could occupy the allosteric pocket between the two monomers of IDH1-R132H homodimer, which accounts for its inhibitory ability. And it is possible to conclude that DC_H31 acts via an allosteric mechanism of inhibition. At the cellular level, DC_H31 could inhibit cell proliferation, promote cell differentiation and reduce the production of 2-HG with a dose-dependent manner in HT1080 cells. Taken together, DC_H31 is a potent selective inhibitor of IDH1-R132H/C both in vitro and in vivo, which can promote the development of more potent pan-inhibitors against IDH1-R132H/C through further structural decoration and provide a new insight for the pharmacological treatment of gliomas.

Identification of 5-benzylidene-2-phenylthiazolones as potent PRMT5 inhibitors by virtual screening, structural optimization and biological evaluations.

Protein arginine methyltransferase 5 (PRMT5) is an epigenetics related enzyme that has been validated as an important therapeutic target for glioblastoma and mantel cell lymphoma. In the present study, 11 novel PRMT5 inhibitors with 5-benzylidene-2-phenylthiazolone scaffold were identified by molecular docking-based virtual screening and structural optimization. Their IC50 values against PRMT5 at enzymatic level were ranging from 0.77 to 23 µM. As expected, the top two active hits (5 and 19) showed potent anti-proliferative activity against MV4-11 cells with EC50 values lower than 10 µM and reduced the cellular symmetric arginine dimethylation levels of SmD3 protein. Besides, 5 and 19 demonstrated the mechanism of cell killing in cell cycle arrest and apoptotic effect. The probable binding modes of the two compounds were explored and further verified by molecular dynamics simulation. The structure-activity relationship (SAR) of this class of structures was also discussed and further demonstrated by molecular docking simulation.

Identification of a novel selective small-molecule inhibitor of protein arginine methyltransferase 5 (PRMT5) by virtual screening, resynthesis and biological evaluations.

As one of the most promising anticancer target in protein arginine methyltransferase (PRMT) family, PRMT5 has been drawing more and more attentions, and many efforts have been devoted to develop its inhibitors. In this study, three PRMT5 inhibitors (9, 16, and 23) with novel scaffolds were identified by performing pharmacophore- and docking-based virtual screening combined with in vitro radiometric-based scintillation proximity assay (SPA). Substructure search based on the scaffold of the most active 9 afforded 26 additional analogues, and SPA results indicated that two analogues (9-1 and 9-2) showed increased PRMT5 inhibitory activity compared with the parental compound. Resynthesis of 9, 9-1, and 9-2 confirmed their PRMT5 enzymatic inhibition activity. In addition, compound 9-1 displayed selectivity against PRMT5 over other key homological members (PRMT1 and CARM1 (PRMT4)). While the structure-activity relationship (SAR) of this series of compounds was discussed to provide clues for further structure optimization, the probable binding modes of active compounds were also probed by molecular docking and molecular dynamics simulations. Finally, the antiproliferative effect of 9-1 on MV4-11 leukemia cell line was confirmed and its impact on regulating the target gene of PRMT5 was also validated. The hit compounds identified in this work have provided more novel scaffolds for future hit-to-lead optimization of small-molecule PRMT5 inhibitors.

Discovery of potent DOT1L inhibitors by AlphaLISA based High Throughput Screening assay.

DOT1L (the disruptor of telomeric silencing 1-like), through its methyltransferase activity of H3K79, plays essential roles in transcriptional regulation, cell cycle regulation, and DNA damage response. In addition, DOT1L is believed to be involved in the development of MLL-rearranged leukemia driven by the MLL (mixed-lineage leukemia) fusion proteins, which thus to be a crucial target for leukemia therapy. Hence, discovering of novel DOT1L inhibitors has been in a great demand. In this study, we initiated the discovering process from setting up the AlphaLISA based High Throughput Screening (HTS) assay of DOT1L. Combining with radioactive inhibition assay and Surface Plasmon Resonance (SPR) binding assay, we identified compound 3 and its active analogues as novel DOT1L inhibitors with IC50 values range from 7 µM to 20 µM in vitro. Together with the analysis of structure activity relationships (SAR) and binding modes of these compounds, we provided clues to assist in the future development of more potent DOT1L inhibitors. Moreover, compounds 3 and 9 effectively inhibited the proliferation of MLL-rearranged leukemia cells MV4-11, which could induce cell cycle arrest and apoptosis. In conclusion, we developed a HTS platform based on AlphaLISA method for screening and discovery of DOT1L novel inhibitor, through which we discovered compound 3 and its analogues as potent DOT1L inhibitors with promising MLL-rearranged leukemia therapeutic application.

Genomic Variants in NEURL, GJA1 and CUX2 Significantly Increase Genetic Susceptibility to Atrial Fibrillation.

Atrial fibrillation (AF) is the most common arrhythmia. In 2014, two new meta-GWAS identified 5 AF loci, including the NEURL locus, GJA1 locus, CAND2 locus, and TBX5 locus in the European ancestry populations and the NEURL locus and CUX2 locus in a Japanese population. The TBX5 locus for AF was reported by us in 2013 in the Chinese population. Here we assessed the association between AF and SNPs in the NEURL, GJA1, CAND2 and CUX2 loci in the Chinese Han population. We carried out a large case-control association study with 1,164 AF patients and 1,460 controls. Significant allelic and genotypic associations were identified between NEURL variant rs6584555 and GJA1 variant rs13216675 and AF. Significant genotypic association was found between CUX2 SNP rs6490029 and AF. No association was found between CAND2 variant rs4642101 and AF, which may be due to an insufficient power of the sample size for rs4642101. Together with our previous findings, seven of fifteen AF loci (<50%) identified by GWAS in the European ancestry populations conferred susceptibility to AF in the Chinese population, and explained approximately 14.5% of AF heritability. On the other hand, two AF loci identified in the Japanese population were both replicated in the Chinese population.

Development of a high-throughput fluorescence polarization assay for the discovery of EZH2-EED interaction inhibitors.

Aberrant activity of enhancer of zeste homolog 2 (EZH2) is associated with a wide range of human cancers. The interaction of EZH2 with embryonic ectoderm development (EED) is required for EZH2's catalytic activity. Inhibition of the EZH2-EED complex thus represents a novel strategy for interfering with the oncogenic potentials of EZH2 by targeting both its catalytic and non-catalytic functions. To date, there have been no reported high-throughput screening (HTS) assays for inhibitors acting at the EZH2-EED interface. In this study, we developed a fluorescence polarization (FP)-based HTS system for the discovery of EZH2-EED interaction inhibitors. The tracer peptide sequences, positions of fluorescein labeling, and a variety of physicochemical conditions were optimized. The high Z' factors (>0.9) at a variety of DMSO concentrations suggested that this system is robust and suitable for HTS. The minimal sequence requirement for the EZH2-EED interaction was determined by using this system. A pilot screening of an in-house compound library containing 1600 FDA-approved drugs identified four compounds (apomorphine hydrochloride, oxyphenbutazone, nifedipine and ergonovine maleate) as potential EZH2-EED interaction inhibitors.

Genomic Variant in IL-37 Confers A Significant Risk of Coronary Artery Disease.

The interleukin 1 family plays an important role in the immune and inflammatory responses. Coronary artery disease (CAD) is a chronic inflammatory disease. However, the genetic association between IL-37, the seventh member of the IL-1 family, and CAD is unknown. Here we show that a single nucleotide polymorphism in the IL-37 gene (rs3811047) confers a significant risk of CAD. We have performed an association analysis between rs3811047 and CAD in two independent populations with 2,501 patients and 3,116 controls from China. Quantitative RT-PCR analysis has been performed to determine if the IL-37 expression level is influenced by rs3811047. We show that the minor allele A of rs3811047 is significantly associated with CAD in two independent populations under a recessive model (Padj = 5.51 × 10-3/OR = 1.56 in the GeneID Northernern population and Padj = 1.23 × 10-3/OR = 1.45 in the GeneID Central population). The association became more significant in the combined population (Padj = 9.70 × 10-6/OR = 1.47). Moreover, the association remains significant in a CAD case control population matched for age and sex. Allele A of rs3811047 shows significant association with a decreased mRNA expression level of IL-37 (n = 168, P = 3.78 × 10-4). These data suggest that IL37 is a new susceptibility gene for CAD, which provides a potential target for the prevention and treatment of CAD.

Small-Molecule Targeting of E3 Ligase Adaptor SPOP in Kidney Cancer.

In the cytoplasm of virtually all clear-cell renal cell carcinoma (ccRCC), speckle-type POZ protein (SPOP) is overexpressed and misallocated, which may induce proliferation and promote kidney tumorigenesis. In normal cells, however, SPOP is located in the nucleus and induces apoptosis. Here we show that a structure-based design and subsequent hit optimization yield small molecules that can inhibit the SPOP-substrate protein interaction and can suppress oncogenic SPOP-signaling pathways. These inhibitors kill human ccRCC cells that are dependent on oncogenic cytoplasmic SPOP. Notably, these inhibitors minimally affect the viability of other cells in which SPOP is not accumulated in the cytoplasm. Our findings validate the SPOP-substrate protein interaction as an attractive target specific to ccRCC that may yield novel drug discovery efforts.

Identification of novel EZH2 inhibitors through pharmacophore-based virtual screening and biological assays.

Polycomb repressive complex 2 (PRC2) acts as a primary writer for di- and tri-methylation of histone H3 at lysine 27. This protein plays an essential role in silencing gene expression. Enhancer of zeste 2 (EZH2), the catalytic subunit of PRC2, is considered as a promising therapeutic target for cancer. GSK126, a specific inhibitor of EZH2, is undergoing phase I trials for hypermethylation-related cancers. In addition, many derivatives of GSK126 are also commonly used in laboratory investigations. However, studies on the mechanism and drug development of EZH2 are limited by the absence of structural diversity of these inhibitors because they share similar SAM-like scaffolds. In this study, we generated a pharmacophore model based on reported EZH2 inhibitors and performed in silico screenings. Experimental validations led to the identification of two novel EZH2 inhibitors, DCE_42 and DCE_254, with IC50 values of 23 and 11µM, respectively. They also displayed significant anti-proliferation activity against lymphoma cell lines. Thus, we discovered potent EZH2 inhibitors with novel scaffold using combined in silico screening and experimental study. Results from this study can also guide further development of novel specific EZH2 inhibitors.

Identification of Novel Disruptor of Telomeric Silencing 1-like (DOT1L) Inhibitors through Structure-Based Virtual Screening and Biological Assays.

Histone methyltransferases are involved in many important biological processes, and abnormalities in these enzymes are associated with tumorigenesis and progression. Disruptor of telomeric silencing 1-like (DOT1L), a key hub in histone lysine methyltransferases, has been reported to play an important role in the processes of mixed-lineage leukemia (MLL)-rearranged leukemias and validated to be a potential therapeutic target. In this study, we identified a novel DOT1L inhibitor, DC_L115 (CAS no. 1163729-79-0), by combining structure-based virtual screening with biochemical analyses. This potent inhibitor DC_L115 shows high inhibitory activity toward DOT1L (IC50 = 1.5 µM). Through a process of surface plasmon resonance-based binding assays, DC_L115 was founded to bind to DOT1L with a binding affinity of 0.6 µM in vitro. Moreover, this compound selectively inhibits MLL-rearranged cell proliferation with an IC50 value of 37.1 µM. We further predicted the binding modes of DC_L115 through molecular docking analysis and found that the inhibitor competitively occupies the binding site of S-adenosylmethionine. Overall, this study demonstrates the development of potent DOT1L inhibitors with novel scaffolds.

Molecular Basis of Gene-Gene Interaction: Cyclic Cross-Regulation of Gene Expression and Post-GWAS Gene-Gene Interaction Involved in Atrial Fibrillation.

Atrial fibrillation (AF) is the most common cardiac arrhythmia at the clinic. Recent GWAS identified several variants associated with AF, but they account for <10% of heritability. Gene-gene interaction is assumed to account for a significant portion of missing heritability. Among GWAS loci for AF, only three were replicated in the Chinese Han population, including SNP rs2106261 (G/A substitution) in ZFHX3, rs2200733 (C/T substitution) near PITX2c, and rs3807989 (A/G substitution) in CAV1. Thus, we analyzed the interaction among these three AF loci. We demonstrated significant interaction between rs2106261 and rs2200733 in three independent populations and combined population with 2,020 cases/5,315 controls. Compared to non-risk genotype GGCC, two-locus risk genotype AATT showed the highest odds ratio in three independent populations and the combined population (OR=5.36 (95% CI 3.87-7.43), P=8.00×10-24). The OR of 5.36 for AATT was significantly higher than the combined OR of 3.31 for both GGTT and AACC, suggesting a synergistic interaction between rs2106261 and rs2200733. Relative excess risk due to interaction (RERI) analysis also revealed significant interaction between rs2106261 and rs2200733 when exposed two copies of risk alleles (RERI=2.87, P<1.00×10-4) or exposed to one additional copy of risk allele (RERI=1.29, P<1.00×10-4). The INTERSNP program identified significant genotypic interaction between rs2106261 and rs2200733 under an additive by additive model (OR=0.85, 95% CI: 0.74-0.97, P=0.02). Mechanistically, PITX2c negatively regulates expression of miR-1, which negatively regulates expression of ZFHX3, resulting in a positive regulation of ZFHX3 by PITX2c; ZFHX3 positively regulates expression of PITX2C, resulting in a cyclic loop of cross-regulation between ZFHX3 and PITX2c. Both ZFHX3 and PITX2c regulate expression of NPPA, TBX5 and NKX2.5. These results suggest that cyclic cross-regulation of gene expression is a molecular basis for gene-gene interactions involved in genetics of complex disease traits.

Astemizole arrests the proliferation of cancer cells by disrupting the EZH2-EED interaction of polycomb repressive complex 2.

Polycomb Repressive Complex 2 (PRC2) modulates the chromatin structure and transcriptional repression by trimethylation lysine 27 of histone H3 (H3K27me3), a process that necessitates the protein-protein interaction (PPI) between the catalytic subunit EZH2 and EED. Deregulated PRC2 is intimately involved in tumorigenesis and progression, making it an invaluable target for epigenetic cancer therapy. However, until now, there have been no reported small molecule compounds targeting the EZH2-EED interactions. In the present study, we identified astemizole, an FDA-approved drug, as a small molecule inhibitor of the EZH2-EED interaction of PRC2. The disruption of the EZH2-EED interaction by astemizole destabilizes the PRC2 complex and inhibits its methyltransferase activity in cancer cells. Multiple lines of evidence have demonstrated that astemizole arrests the proliferation of PRC2-driven lymphomas primarily by disabling the PRC2 complex. Our findings demonstrate the chemical tractability of the difficult PPI target by a small molecule compound, highlighting the therapeutic promise for PRC2-driven human cancers via targeted destruction of the EZH2-EED complex.