EZH2 (Ki = 24 nM)

EPZ005687 exhibits an IC50 value of 54±5 nM, indicating concentration-dependent reduction of PRC2 enzymatic activity. H3K27 methylation in lymphoma cells is particularly inhibited by EPZ005687. The proliferation of the EZH2Y641F-bearing cell line is significantly impacted by EPZ005687. In mutant EZH2 lymphoma cells, but not in wild-type cells, EPZ005687 inhibits proliferation[1]. U937 cells undergo a clear apoptosis in response to EPZ005687 at doses of 0.5, 1, 5, and 10 µM. The proliferation of U937 cells is clearly inhibited by EPZ005687, whereas NBMCD34+ cell growth is very slightly affected. EPZ005687 causes blockage of the G1 phase and reduces the proportion of S phase cells in U937 cells. Furthermore, H3K27 methylation in U937 cells is clearly depleted by EPZ005687, whereas H3K27 methylation in NBMCD34+ cells is barely affected[3].

EZH2 Inhibition Protects against TAC-Induced PAH In Vivo [2]
To assess the biological impact of EZH2 on the development of pulmonary hypertension, we first measured the RVSP as an indicator of pulmonary artery pressure in spontaneously breathing mice, following sham control and TAC operation, EPZ005687 or DMSO was injected peritoneally as described in methods. On day 28 after TAC, the RVSBP was markedly higher in the TAC group than in the sham control group (Figures 2(a) and 2(d)). Besides, as shown in Figures 2(b) and 2(c), ratios of RV and lung weight to body weight were significantly increased 2.1-fold and 2.6-fold in TAC mice compared to sham control mice, respectively. EPZ005687 treatment significantly alleviated the further increase of RVSBP, ratios of LV and lung weight to body weight, respectively. These findings suggest that EPZ005687 treatment might have a prominent role in protecting against TAC-induced PAH and RV hypertrophy in vivo.

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EZH2 Inhibition Regulates Oxidative Reactions in Lungs [2]
ROS are important parts of physiological and pathological processes. Recently, ROS are thought to be signaling molecules to mediate specific cellular responses in the vasculature. Moreover, evidence shows that the accumulation of ROS contributes to the development of PAH. To investigate the role of ROS in our TAC-induced PAH model, DHE fluorescence probe was utilized to detect ROS production in murine frozen lung sections. Figure 3(a) showed that EZH2 silencing prevented the induction of ROS production by TAC-induced PAH from 18.3 fold to 4.8 fold compared with sham control. As anticipated, the increase of lung nitrotyrosine caused by TAC-induced PAH was significant inhibited by EPZ005687 treatment (Figure 3(b)). These findings suggest that inhibition of EZH2 reduces oxidative reaction in lungs caused by TAC-induced PAH.

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EZH2 Suppresses SOD1 Transexpression in Lung in TAC-Induced PAH Mice [2]
SOD1 is responsible for destroying free superoxide radicals in the body. In accordance with the oxidative reaction in lungs, the expression of SOD1 was significantly downregulated and the expression of EZH2 was upregulated in TAC + DMSO group as compared with sham control, respectively (Figures 4(a) and 4(b)). Due to the negative correlation between EZH2 and SOD1 expression, and next, we tackled the relationship between EZH2 and SOD1. Interestingly, we observed EPZ005687 treatment could inhibit the expression of EZH2 and reverse the decreased expression of SOD1 (Figures 4(a) and 4(b)). Thus, we hypothesized that EZH2 might promote TAC-induced PAH by targeting SOD1. Chromatin immunoprecipitation (ChIP) assay showed that EZH2 and trimethylated histone H3K27 (H3K27Me3) accumulated on the SOD1 promoter but not the Gapdh promoter in TAC + DMSO group. EPZ005687 treatment was used to validate the role of EZH2 in SOD1 transrepression. Indeed, EPZ005687 treatment could reverse the increased accumulation of EZH2 and H3K27Me3 on SOD1 promoter (Figure 4(c)) and increase SOD1 expression in lung in TAC-induced PAH mice (Figures 4(a) and 4(b)). Combined, these data suggest that EZH2 regulates intracellular ROS levels in response to TAC-induced PAH stimulation through repressing SOD1 transcription.

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Intra-articular injection of EPZ005687 delayed OA development in mice.

Biochemical Enzyme Assays [2]
Preparation of recombinant purified human PRC2 complex containing WT EZH2, Y641 EZH2 mutants, A677G EZH2 or WT EZH1 was performed as previously described 1,2. Chicken erythrocyte oligonucleosomes were purified as previously described 3. Biotinylated histone peptides were synthesized by 21st Century Biochemicals and HPLC-­‐purified to > 95% purity. 384-­‐well Flashplates and Microscint 0 scintillation fluid were purchased commercially and 96-­‐well Multiscreen HTS filter-­‐binding plates were from Millipore. 3H-­‐labeled S-­‐ adenosylmethionine (3H-­‐SAM) was obtained commercially with a specific activity of 80 Ci/mmol. Unlabeled SAM and S-­‐adenosylhomocysteine (SAH) were obtained commercially. Flashplates were washed in a Biotek ELx-­‐ 405 with 0.1% Tween. 384-­‐well Flashplates and 96-­‐well filter binding plates were read on a TopCount microplate reader . Compound serial dilutions were performed on a Freedom EVO and spotted into assay plates using a Thermo Scientific Matrix PlateMate.

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Determination of Enzyme Inhibition IC50 Values [2]
10-­‐point curves of EPZ005687 were made using serial 3-­‐fold dilutions in DMSO, beginning at 2.5 mM (final top concentration of compound was 50 μM and the DMSO was 2%). A 1 μL aliquot the inhibitor dilution series was spotted in a 384-­‐well microtiter plate. The 100% inhibition control consisted of 1 mM final concentration of the product inhibitor S-­‐adenosylhomocysteine, (SAH). Compound was incubated for 30 min with 40 μL per well of 5 nM PRC2 (final assay concentration in 50 μL was 4 nM) in 1X assay buffer (20 mM Bicine [pH 7.6], 0.002% Tween 20, 0.005% Bovine Skin Gelatin and 0.5 mM DTT). 10 μL per well of substrate mix comprising assay buffer 3H-­‐SAM, unlabeled SAM, and peptide representing histone H3 residues 21 – 44 containing C-­‐terminal biotin (appended to a C-­‐terminal amide-­‐capped lysine) were added to initiate the reaction (both substrates were present in the final reaction mixture at their respective Km values, an assay format referred to as ‘‘balanced conditions’’4. The final concentrations of substrates and methylation state of the substrate peptide are indicated for each enzyme in Supplementary Table 7. Reactions were incubated for 90 min at room temperature and quenched with 10 μL per well of 600 μM unlabeled SAM, then transferred to a 384-­‐well Flashplate and washed after 30 min.

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In Vitro EPZ005687-­Substrate Competitions [2]
Experimental conditions for the SAM competitions in 50 μL total volume in 384-­‐well format were similar to the IC50 experiments with the following exceptions.EPZ005687 was serially diluted 2-­‐fold in DMSO (final concentration 2%) to make 10-­‐point curves. SAM was titrated over a range between 0.012 to 15 μM. To monitor the reaction, a radioactive tracer 3H-­‐SAM was used in each reaction, equivalent to up to 250 nM (which was accounted for in the total SAM concentration). At SAM concentrations less than 250 nM, the reaction contained only 3H-­‐SAM. Each SAM concentration had equivalent wells with no enzyme present in the reaction as negative controls to subtract the contribution to background signal of the 3H-­‐SAM. Reactions were incubated for 90 min and quenched with 10 μL per well of 600 μM SAM. Oligonucleosome competitions were performed in 96-­‐well format in the same assay buffer as described in the IC50 determination, except that it was supplemented with 100 mM KCl. EPZ005687 was serially diluted 2-­‐fold in DMSO (final concentration 2%) to make 10-­‐point curves. The oligonucleosome was titrated over 8 points using a 2-­‐fold dilution scheme with top concentration of 500 nM in the final enzyme reaction volume of 50 μL. Reactions were initiated by adding a cocktail of SAM and 3H-­‐SAM, with final respective concentrations of 450 and 150 nM. Reactions were quenched with the addition of 10 μL SAM (600 μM) and 30 μL of the reactions were added to 96-­‐well filter binding plates. The membranes were washed 3 times with 200 μL of 10% tricarboxylic acid followed by washing once with 95% ethanol. The membranes were air dried and 30 μL Microscint 0 was added before reading in a TopCount.

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Magnetic pull-­down of EZH2 to determine effect of EPZ005687 on protein-­ protein interactions within the PRC2 complex [2]
50% suspension of Anti-­‐FLAG M2 magnetic beads was obtained commercially and washed 3 times in 1X assay buffer, consisting of 20 mM bicine (pH = 7.6) and 0.002% Tween20. PRC2 complex (500 nM) containing FLAG-­‐tagged EED was incubated with 10 μM EPZ005687 in 1X assay buffer. The DMSO contribution from addition of the compounds was 1%, so a vehicle control of 1% DMSO was also included. The incubations were then added to 50 μL of washed beads that were resuspended in 50 μL of 1X assay buffer in the wells of a 96-­‐well polypropylene microplate and incubated for 1 h at room temperature. The beads were pulled down using a microplate magnet, and 50 μL of supernatant was removed. The beads were washed 3 times with 100 μL of 1X assay buffer and resuspended in 50 μL of 1X assay buffer. The supernatant and beads were then mixed with an equal volume of 2X SDS-­‐PAGE gel loading buffer and boiled for 10 minutes. The samples were run on an 8% Tris-­‐glycine SDS-­‐PAGE gel for 90 min at 125V, then visualized with GelCode Blue staining.

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Determination of Mutually Exclusive Binding of SAH and EPZ005687 by Yonetani-­Theorell Analysis [2]
SAH and EPZ005687 were serially diluted and spotted into a 384-­‐well microplate in a grid pattern such that all combinations of concentrations of SAH and EPZ005687 were obtained. To this, 40 μL of a mixture containing PRC2 (4 nM) and biotin in 1X assay buffer (20 mM Bicine [pH 7.6], 0.002% Tween 20, 0.005% Bovine Skin Gelatin and 0.5 mM DTT). 10 μL per well of substrate mix comprising assay buffer 3H-­‐SAM (150 nM), unlabeled SAM (1800 nM), and peptide representing histone H3 residues 21 – 44 containing C-­‐terminal biotin (appended to a C-­‐terminal amide-­‐capped lysine) (185 nM) were added to initiate the reaction (both substrates were present in the final reaction mixture at their respective Km values, an assay format referred to as ‘‘balanced conditions’’4. Reactions were incubated for 90 min at room temperature and quenched with 10 μL per well of 600 μM unlabeled SAM, then transferred to a 384-­‐well Flashplate and washed after 30 min. The inverse of the reaction velocity was plotted as a function of SAH concentration at several different concentrations of EPZ005687 to yield a Yonetani-­‐Theorell plot.

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Selectivity of EPZ005687 Against a Panel of 77 Human Ion Channels and GPCRs [2]
EPZ005687 was tested for the displacement of radiolabeled ligands known to bind to 77 human ion channels and GPCRs in a standard panel offered by Cerep. EPZ005687 was tested in duplicate at a concentration of 10 μM and the specific ligand binding to the receptor is defined as the difference between the total binding and the non-­‐specific binding determined in the presence of an excess of unlabeled ligand. The results in Supplementary Table 1 are expressed as percent of control of specific binding ((measured specific control/specific control binding) X 100). Also shown in Supplementary Table 1 are the identities of the reference radioligands and their binding affinities.

Methylation Timecourse: [1]
For days 1-­‐4 of the timecourse, WSU-­‐DLCL2 cells were plated in T-­‐75 flasks for each timepoint, at a final density of 5x104-­‐ 1x105 cells/mL, and treated with either DMSO, or 1.5 or 5.6uM EPZ005687. At each timepoint, cells were harvested by centrifugation, washed with PBS, and histones were extracted as previously described6. A second set of WSU-­‐DLCL2 cells treated with DMSO, or 1.5 or 5.6uM EPZ005687 was set up on day 0, counted on day 4, and split back to the original plating density for the day 5 and 6 timepoints.

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ELISA [1]
Acid extracted histones were prepared from cells in linear log-­‐phase growth which had been treated with EPZ005687 at the indicated final concentrations. Histones were prepared in equivalent concentrations in coating buffer (PBS+0.05%BSA) yielding 0.5 ng/ul of sample, and 100 ul of sample or standard was added in duplicate to two 96-­‐well ELISA plates. The plates were sealed and incubated overnight at 4°C. The following day, plates were washed 3x with 300 ul/well PBST (PBS+0.05% Tween 20; 10X PBST, KPL #51-­‐ 14-­‐02) on a Bio Tek plate washer. Plates were blocked with 300 ul/well of diluent (PBS+2%BSA+0.05% Tween 20), incubated at RT for 2 hours, and washed 3x with PBST. All antibodies were diluted in diluent. 100 ul/well of anti-­‐H3K27me3 or anti-­‐total H3 was added to each plate. Plates were incubated for 90 min at RT and washed 3x with PBST. 100 ul/well of anti-­‐Rb-­‐IgG-­‐HRP was added 1:2,000 to the H3K27Me3 plate and 1:6,000 to the H3 plate and incubated for 90 min at RT. Plates were washed 4X with PBST. For detection, 100 ul/well of TMB substrate was added and plates incubated in the dark at RT for 5 min. Reaction was stopped with 100 ul/well 1N H2SO4 . Absorbance at 450 nm was read on SpectaMax M5 Microplate reader.

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Expression Profiling Sample Preparation [1]
For days 1, 2, and 4 of the timecourse, WSU-­‐DLCL2 cells were plated in 6-­‐well plates for each timepoint, at a final initial seeding density of 1x105 cells/mL, and treated with either DMSO, or 1.5 or 5.6uM EPZ005687. At each timepoint, cells were harvested by centrifugation, washed with PBS, and cell pellets were snap frozen. A second set of WSU-­‐DLCL2 cells treated with DMSO, or 1.5 or 5.6uM EPZ005687 was set up on day 0, counted on day 4, split back to the original plating density, and re-­‐ dosed with DMSO, or 1.5 or 5.6uM EPZ005687 for the day 6 timepoint.

Balb/c mice (6–8 weeks) were assigned randomly to three experimental groups: (a) sham control group, injected peritoneally with DMSO for 4 weeks once a week; (b) TAC group, injected peritoneally with DMSO for 4 weeks once a week; and (c) TAC group, injected peritoneally with EPZ005687 (10 mg kg−1) for 4 weeks once a week. The injection was performed at 1, 8, 15, and 22 days post-TAC or sham operation.[2]

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5.6 μM, 50 μL; intra-articular injection

Osteoarthritis (OA) mouse model

[1]. A selective inhibitor of EZH2 blocks H3K27 methylation and kills mutant lymphoma cells. Nat Chem Biol. 2012;8(11):890-6.

[2]. EZH2 Inhibition Ameliorates Transverse Aortic Constriction-Induced Pulmonary Arterial Hypertension in Mice. Can Respir J. 2018 Feb 28;2018:9174926.

[3]. Effects of H3K27 methylation inhibitor EPZ005687 on apoptosis, proliferation and cell cycle of U937 cells and normal CD34 positive cells. Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2014 Dec;22(6):1561-6.

1-cyclopentyl-N-[(4,6-dimethyl-2-oxo-1H-pyridin-3-yl)methyl]-6-[4-(4-morpholinylmethyl)phenyl]-4-indazolecarboxamide is a member of indazoles.

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EZH2 catalyzes trimethylation of histone H3 lysine 27 (H3K27). Point mutations of EZH2 at Tyr641 and Ala677 occur in subpopulations of non-Hodgkin's lymphoma, where they drive H3K27 hypertrimethylation. Here we report the discovery of EPZ005687, a potent inhibitor of EZH2 (K(i) of 24 nM). EPZ005687 has greater than 500-fold selectivity against 15 other protein methyltransferases and has 50-fold selectivity against the closely related enzyme EZH1. The compound reduces H3K27 methylation in various lymphoma cells; this translates into apoptotic cell killing in heterozygous Tyr641 or Ala677 mutant cells, with minimal effects on the proliferation of wild-type cells. These data suggest that genetic alteration of EZH2 (for example, mutations at Tyr641 or Ala677) results in a critical dependency on enzymatic activity for proliferation (that is, the equivalent of oncogene addiction), thus portending the clinical use of EZH2 inhibitors for cancers in which EZH2 is genetically altered.[1]

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EPZ005687 is a selective inhibiter of methyltransferase EZH2. In this article, we investigated the protective role and mechanism of EPZ005687 in transverse aortic constriction-induced pulmonary arterial hypertension in mice. Methods We assigned 15 (6–8 weeks old) male balb/c mice to 3 groups randomly: Sham control + DMSO group, TAC + DMSO group, and TAC + EPZ005687 group (10 mg kg−1, once a week for 4 weeks). On day 28 following TAC operation, the right ventricular systolic blood pressure (RVSBP) was measured, and lung tissues were collected for laboratory examinations (DHE, Western blot, real-time PCR, and ChIP). Results Murine PAH model was successfully created by TAC operation as evidenced by increased RVSBP and hypertrophic right ventricle. Compared with the sham control, TAC-induced PAH markedly upregulated the expression of EZH2 and ROS deposition in lungs in PAH mice. The inhibiter of methyltransferase EZH2, EPZ005687 significantly inhibits the development of TAC-induced PAH in an EZH2-SOD1-ROS dependent manner. Conclusion Our data identified that EZH2 serves a fundamental role in TAC-induced PAH, and administration of EPZ005687 might represent a novel therapeutic target for the treatment of TAC-induced PAH.[2] The aim of this study was to investigate the effects of H3K27 methylation inhibitor EPZ005687 on the apoptosis, proliferation and cell cycle of U937 cells and normal CD34⁺ cells. The U937 cells and normal CD34⁺ cells were treated with different concentration of EPZ005687 at different time points. The apoptosis rate was determined by Annexin V/PI staining. The cell proliferation and cell cycle was determined using WST-1 assay and 7-AAD assay, respectively. The activity of H3K27 methylation was detected by chemiluminescent immunoassay. The results showed that the EPZ005687 induced an obvious apoptosis of U937 cells. The apoptotic rate was 3.96% ± 0.79%,5.74% ± 0.73%,13.34% ± 1.77% and 25.24% ± 2.55% in U937 cells treated with 0.5, 1, 5 and 10 µmol/L EPZ005687 for 48 hours, respectively. However, EPZ005687 had rare effect on normal bone marrow(NBM) CD34⁺ cells. The apoptotic rate was 3.64% ± 0.62%,4.28% ± 0.99%,6.18% ± 1.19% and 7.56% ± 1.34% after U937 cells were treated with 0.5, 1, 5 and 10 µmol/L EPZ005687 for 48 hours, respectively. EPZ005687 inhibited obviously the proliferation of U937 cells but had weak effect on the proliferation of NBMCD34⁺ cells. The inhibitory effect of EPZ005687 on U937 cells was time-dependent after treated with 0.5, 1, 5 and 10 µmol/L EPZ005687 from 12 to 96 hours. EPZ005687 induced G1 phase blocking (G1%, 64.18% ± 13.27% vs 49.43% ± 12.54%) and decreased the percentage of cells in S phase (9.67% ± 2.61% vs15.26% ± 5.58%) in U937 cells. However, EPZ005687 had no effect on the cell cycle of NBMCD34⁺ cells. In addition, EPZ005687 produced obviously depletion of H3K27 methylation in U937 cells (P < 0.05), but hardly had effect on the H3K27 methylation of NBMCD34⁺ cells. It is concluded that the EPZ005687 inhibites proliferation, induces apoptosis and cell cycle blocking in G1 phase in leukemia cells. This agent may have potential value in clinical application.[3]

C32H37N5O3

539.67

539.289

1396772-26-1

60160561

Off-white to yellow solid powder

1.3±0.1 g/cm3

797.9±60.0 °C at 760 mmHg

436.4±32.9 °C

0.0±2.8 mmHg at 25°C

1.676

2.96

2

5

7

40

991

0

ZOIBZSZLMJDVDQ-UHFFFAOYSA-N

InChI=1S/C32H37N5O3/c1-21-15-22(2)35-32(39)28(21)18-33-31(38)27-16-25(17-30-29(27)19-34-37(30)26-5-3-4-6-26)24-9-7-23(8-10-24)20-36-11-13-40-14-12-36/h7-10,15-17,19,26H,3-6,11-14,18,20H2,1-2H3,(H,33,38)(H,35,39)

1-cyclopentyl-N-((4,6-dimethyl-2-oxo-1,2-dihydropyridin-3-yl)methyl)-6-(4-(morpholinomethyl)phenyl)-1H-indazole-4-carboxamide.

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 1.67 mg/mL (3.09 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 16.7 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 1.67 mg/mL (3.09 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 16.7 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 1.67 mg/mL (3.09 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 16.7 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)