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Effective removal of strontium isotopes in radioactive waste streams has important implications for the environment and the sustainable development of nuclear energy.

CREB (cyclic-AMP responsive element binding protein) binding protein (CBP) is a potential target for prostate cancer treatment. Herein, we report the structural optimization of a series of 1-(indolizin-3-yl)ethan-1-one compounds as new selective CBP bromodomain inhibitors, aiming to improve cellular potency and metabolic stability. This process led to compound

The hollow fiber membrane energy accumulator (HFMEA) and the flat membrane energy accumulator (FMEA) were designed. Dynamic mathematic models of the heat and mass transfer in the full-scale membrane energy accumulators (MEAs) were built in order to consider the membrane-to-membrane interactions and boundary effect in MEAs. The reliability of mathematic models has been verified by the experimental results. The maximum relative deviations of the mass transfer flux and solution temperature were 14.9 % and 14.6 %, respectively. The change rate of LiBr mass fraction in the FMEA was 1.38 times of that in the HFMEA. The hollow fiber membrane bundle in HFMEA is more conducive to the mass transfer process when the arrangement of the fibers is triangular. When the length of the membrane channel increased from 50 mm to 160 mm in HFMEA, the mass transfer per membrane surface area decreased by about 5 %. With increasing the vapor inlet pressure from 700 Pa to 1500 Pa, the mass transfer flux was tripled. And the average temperature of the solution increased by more than 3.75°C in 10 minutes. If the membrane filled density increased from 1.4 % to 2.1 %, the mass transfer flux increased to 2.04 times in FMEA.

Cancer recurrence after surgery remains an unresolved clinical problem1–3. Myeloid cells derived from bone marrow contribute to the formation of the premetastatic microenvironment, which is required for disseminating tumour cells to engraft distant sites4–6. There are currently no effective interventions that prevent the formation of the premetastatic microenvironment6,7. Here we show that, after surgical removal of primary lung, breast and oesophageal cancers, low-dose adjuvant epigenetic therapy disrupts the premetastatic microenvironment and inhibits both the formation and growth of lung metastases through its selective effect on myeloid-derived suppressor cells (MDSCs). In mouse models of pulmonary metastases, MDSCs are key factors in the formation of the premetastatic microenvironment after resection of primary tumours. Adjuvant epigenetic therapy that uses low-dose DNA methyltransferase and histone deacetylase inhibitors, 5-azacytidine and entinostat, disrupts the premetastatic niche by inhibiting the trafficking of MDSCs through the downregulation of CCR2 and CXCR2, and by promoting MDSC differentiation into a more-interstitial macrophage-like phenotype. A decreased accumulation of MDSCs in the premetastatic lung produces longer periods of disease-free survival and increased overall survival, compared with chemotherapy. Our data demonstrate that, even after removal of the primary tumour, MDSCs contribute to the development of premetastatic niches and settlement of residual tumour cells. A combination of low-dose adjuvant epigenetic modifiers that disrupts this premetastatic microenvironment and inhibits metastases may permit an adjuvant approach to cancer therapy. In mouse models of pulmonary metastasis, adjuvant epigenetic therapy targeting myeloid-derived suppressor cells disrupts the premetastatic microenvironment after resection of primary tumours and inhibits the dissemination of residual tumour cells.

The selective hydrogenation of phenol to cyclohexanone is an important process in the chemical industry. However, achieving high selectivity at high conversion rates is highly challenging, particularly under continuous reaction conditions. Here, we found that the presence of Na alkaline additives (NaX, X = CO32–, HCO3–, or OH–) on Pd/Al2O3 not only promoted the phenol conversion from 8.3% to >99% but also increased the cyclohexanone selectivity from 89% to >97% during the continuous hydrogenation of phenol on a fixed bed reactor. After 1200 h of continuous reaction, no activity or selectivity attenuation was observed and the turnover number was approximately 2.9 × 105. Density functional theory calculations, spectroscopic, and dynamics studies demonstrated that the addition of NaX greatly promoted phenol adsorption and hydrogen activation, thereby improving catalytic activity. Simultaneously, the formation of a “-C=O-Na-” intermediate inhibited the excessive hydrogenation and intermolecular coupling of cyclohexanone, leading to high selectivity.

This study aims to validate whether bone marrow stromal cells (BMSCs) transplantation could promote the resolution and recanalization of deep vein thrombosis (DVT) and to explore the underlying mechanism. The right hind femoral vein was embolized to establish the DVT rabbit model. BMSCs from New Zealand white rabbits were isolated and identified, and then injected into DVT rabbits. After that, the extent of angiogenesis was determined by the amount of capillaries that were positive for antibody against vWF. Macrophage infiltration was measured by immunohistochemistry with F4/80 antibody. M1 or M2 macrophages were identified as F4/80 + CD11c + or F4/80 + CD206 + cells by using flow cytometry analysis, respectively. BMSCs were successfully isolated and identified. BMSCs transplantation promotes macrophage infiltration and angiogenesis in DVT rabbits. BMSCs transplantation causes M1/M2 polarization, altered cytokine production and increased monocyte chemotactic protein 1 (MCP-1) protein expression in DVT rabbits. However, injection of MCP-1 protein not only reversed the effects of BMSCs transplantation on macrophage infiltration and angiogenesis, but also reversed the effects of BMSCs transplantation on M1/M2 polarization and cytokine production in DVT rabbits. BMSCs transplantation promotes the resolution and recanalization of DVT in rabbits through regulating macrophage infiltration and angiogenesis, the underlying mechanism is associated with MCP-1 expression.

Electrospun polymer nanofibers have gained much attention in blood vessel tissue engineering. However, conventional nanofiber materials with the deficiencies of slow endothelialization and thrombosis are not effective in promoting blood vessel tissue repair and regeneration. Herein, biomimetic gelatin (Gt)/polycaprolactone (PCL) composite nanofibers incorporating a different amount of chondroitin sulfate (CS) were developed via electrospinning technology to investigate their effects on antithrombogenicity and endothelial cell affinity. Varying CS concentrations in PG nanofibers affects fiber morphology and diameter. The CS/Gt/PCL nanofibers have suitable porosity (~ 80%) and PBS solution absorption (up to 650%). The introduction of CS in Gt/PCL nanofibers greatly enhances their anticoagulant properties, prolongs their coagulation time, and facilitates cell responses. Particularly, 10%CS/Gt/PCL nanofibers display favorable cell attachment, elongation, and proliferation. Thus, the Gt/PCL nanofibers containing a certain amount of CS could be excellent candidates as a promising tissue-engineering scaffold in blood vessel repair and regeneration.

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 A. 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.

Background: Chronic liver disease is traditionally conceived as a risk factor for cardiovascular surgery. Transcatheter aortic valve implantation (TAVI) has recently burgeoned to precede surgical aortic valve replacement (SAVR) in patients with severe aortic stenosis at intermediate to high surgical risk. The evidence regarding TAVI in the patients with chronic liver disease is currently scarce. Methods: This article aims to assess the application of TAVI technique in the patients with chronic liver disease. Results: TAVI in the patients with chronic liver disease produced acceptable postoperative results. The post-TAVI outcomes were comparable between the patients with or without chronic liver disease, except for a lower rate of pacemaker implantation in the patients with chronic liver disease (OR, 0.49[0.27–0.87], P = .02). In the patients with chronic liver disease, compared to SAVR, TAVI led to a decrease in the in-hospital mortality (OR, 0.43[0.22–0.86], P = .02) and need for transfusion (OR, 0.39[0.25–0.62], P

Fatty alcohols are widely used as detergents, but the large-scale synthesis still involves serious environmental pollution due to the use of toxic Cr-containing catalysts. Herein, a series of eco-friendly NixFey catalysts were successfully developed by utilizing a facile in-situ carbonization and reduction method, which exhibited excellent selectivity in the hydrogenation of stearic acid. The best performance was achieved on the Ni1.8Fe1.5 catalyst with 98% selectivity at 100% stearic acid conversion towards stearic alcohol. Further investigation revealed that Ni 3 Fe intermetallic compound was the effective active component. Besides, this catalyst can be easily separated and reused for several times without significant loss of activity.

Selective hydrogenation of phenol to cyclohexanone has attracted a great deal of attentions both in industry and academic field. Here in this review, the significances, strategies and mechanisms for the production of cyclohexanone are briefly described. Then, we mainly summarize the evolution of phenol hydrogenation in gas/liquid phase by the classification of catalyst types. In situ hydrogenation techniques including catalytic transfer hydrogenation (CTH) and electro-catalytic hydrogenation (ECH) of phenol are also discussed. Despite technology of catalyst design has been developed rapidly within the past decades, the direct evidences to understand the reaction mechanisms and kinetics are still scarce. Therefore, it is still of great challenge to explore the function mechanisms and design advanced catalysts with high activity and high selectivity (>95%) for direct hydrogenation of phenol to cyclohexanone. This review may provide guidance for these attempts.

Metastasis is the major dominant reason for poor prognosis of hepatocellular carcinoma (HCC) after surgical treatment. However, the molecular mechanism of metastasis has not been well characterzied. Here, we report a novel function of Barx homeobox1 (Barx1) in inhibiting HCC invasion and metastasis. Barx1 expression is significantly decreased in human HCC tissues than in adjacent non-tumorous tissues and normal liver tissues. Low Barx1 expression is correlated with higher tumor-nodule-metastasis stage and indicates poor prognosis. Down-regulation of Barx1 promotes HCC migration, invasion and metastasis, whereas up-regulation of Barx1 inhibits HCC migration, invasion and metastasis. Mannosyl (alpha-1,6-)-glycoprotein beta-1,6-N-acetyl-glucosaminyltransferase 5 (MGAT5) and matrix metallopeptidase 9 (MMP9) are direct target genes of Barx1. Knockdown of Barx1 up-regulates MGAT5 and MMP9 expression in HCC cells with low metastatic capability, whereas over-expression of Barx1 suppresses their expression in HCC cells with high metastatic capability. Knockdown of both MGAT5 and MMP9 significantly decreases the invasion and metastasis abilities induced by Barx1 knockdown. Barx1 expression is negatively correlated with MGAT5 and MMP9 expression in human HCC tissues. Patients with low expression of Barx1 and high expression of MGAT5 or MMP9 are associated with poorer prognosis. Thus, loss of Barx1 represents a prognostic biomarker in human HCC patients.

INTRODUCTION Recently transcatheter aortic valve replacement (TAVR) has emerged as a feasible alternative for traditional surgical aortic valve replacement (SAVR) in patients with intermediate to high risk. There is currently no clear consensus regarding the optimal antiplatelet strategy after TAVR. The primary objective of this updated meta-analyses was to compare the outcomes of dual antiplatelet therapy (DAPT) versus single antiplatelet therapy (SAPT) following TAVR. EVIDENCE ACQUISITION A meta-analysis of eligible studies of patients undergoing TAVR which reported our outcomes of postoperative DAPT in comparison with SAPT, was carried out. The outcomes included the all-cause mortality, stroke, major/life-threatening bleeding, myocardial infarction and a composite endpoint of mortality, stroke, bleeding and myocardial infarction. EVIDENCE SYNTHESIS Three randomized controlled trials (RCTs, N.=421) and 5 observational studies (N.=6683) were included in this updated meta-analysis. All-cause mortality was comparable between the two groups (OR 1.13 [95% CI: 0.70-1.81], P=0.619). Besides, DAPT resulted in an augmented risk of major/life-threatening bleeding (OR 2.45 [95% CI: 1.08-5.59], P=0.032). No statistically significant difference was found between the two groups in the rates of stroke (OR 0.83 [95% CI: 0.62-1.10], P=0.212) and myocardial infarction (OR 1.17 [95% CI: 0.47-2.91], P=0.728). And DAPT led to an increased rate of the composite endpoint (OR 2.39 [95% CI: 1.63-3.50], P

Summary UHRF1 facilitates the establishment and maintenance of DNA methylation patterns in mammalian cells. The establishment domains are defined, including E3 ligase function, but the maintenance domains are poorly characterized. Here, we demonstrate that UHRF1 histone- and hemimethylated DNA binding functions, but not E3 ligase activity, maintain cancer-specific DNA methylation in human colorectal cancer (CRC) cells. Disrupting either chromatin reader activity reverses DNA hypermethylation, reactivates epigenetically silenced tumor suppressor genes (TSGs), and reduces CRC oncogenic properties. Moreover, an inverse correlation between high UHRF1 and low TSG expression tracks with CRC progression and reduced patient survival. Defining critical UHRF1 domain functions and its relationship with CRC prognosis suggests directions for, and value of, targeting this protein to develop therapeutic DNA demethylating agents.

We addressed the precursor role of aging-like spontaneous promoter DNA hypermethylation in initiating tumorigenesis. Using mouse colon-derived organoids, we show that promoter hypermethylation spontaneously arises in cells mimicking the human aging-like phenotype. The silenced genes activate the Wnt pathway, causing a stem-like state and differentiation defects. These changes render aged organoids profoundly more sensitive than young ones to transformation by Braf(V600E), producing the typical human proximal BRAF(V600E)- driven colon adenocarcinomas characterized by extensive, abnormal gene-promoter CpG-island methylation, or the methylator phenotype (CIMP). Conversely, CRISPR-mediated simultaneous inactivation of a panel of the silenced genes markedly sensitizes to Braf(V600E)-induced transformation. Our studies tightly link aging-like epigenetic abnormalities to intestinal cell fate changes and predisposition to oncogene-driven colon tumorigenesis.

Cancer recurrence after surgery remains an unresolved clinical problem

Aims Abdominal aortic aneurysm (AAA) is a multi-factorial progressive vascular disease characterized by chronic inflammatory cell infiltration. We investigated the roles played by IFI16 and ASC inflammasomes in AAA development and progression. Materials and methods Western blot and qRT-PCR studies were performed to analyze the expression of relative genes in AAA specimens and mouse vascular smooth muscle cells (VSMCs). The apoptosis rates and ROS levels of VSMCs were assessed by flow cytometry. Transwell assays were performed to analyze the migration ability of VSMCs. The levels of MCP-1, IL-1β, and IL-6 in the supernatants of cultured VSMCs were analyzed by ELISA. Key findings Increased levels of IFI16 expression were found in AAA specimens and Ang-II-treated VSMCs. IFI16 and ASC silencing suppressed the apoptosis and migration ability of VSMCs undergoing Ang-II treatment, reduced elasticity damage to the aortic wall, and decreased the levels of MMP expression. The effect of IFI16 knockdown in Ang-II-induced VSMCs was reversed by MCPIP1 overexpression. Significance Our data suggest that an up-regulation of IFI16 and ASC expression might promote the apoptosis of VSMCs, enhance the inflammatory response, and impairs vascular wall elasticity via a MCPIP1-related mechanism. The inflammasome components IFI16 and ASC might be involved in AAA progression and serve as target molecules for diagnosing and treating AAA.

Thromboangiitis obliterans (TAO), also known as Buerger's disease, is a nonatherosclerotic inflammatory disease that influences medium- and small-sized blood vessels of extremities. However, mechanisms underlying TAO are still unclear. As a mediator associated with inflammation, A disintegrin and metalloprotease 10 (ADAM10) was hypothesized to play inhibitory roles in the development of TAO. Thus, the objective of this study is to investigate the effects of ADAM10 in a sodium laurate-induced TAO rat model and elucidate underlying mechanisms. Male Wistar rats were randomly divided into four groups (n = 6) for treatment: sham-operated (SHAM), TAO model (TAO), ADAM10 low dose injection (3 mg/kg; ADAM10-LD) and ADAM10 high dose injection (6 mg/kg; ADAM10-HD). After 14-day treatment, color Doppler ultrasound and hematology analysis indicated TAO rats displayed higher whole blood viscosity and blood platelet count compared with those in the SHAM group. Histologic evaluation and transmission electron microscopy revealed that the ultrastructural damages of vascular smooth muscle and endothelial cells were observed in TAO rats, such as fractured endoplasmic reticulum, decreased cell counts, and fibrillation. On the other hand, the typical signs and symptoms of TAO rats were significantly alleviated via ADAM10 treatment with a dose-dependent pattern. Real-time PCR and western blot results revealed that the expression of high-mobility-group box 1 (HMGB1), receptor for advanced glycation end-products (RAGE) and nuclear factor-kappa B (NF-κB) increased in TAO rats whereas decreased by ADAM10 treatment in both mRNA and protein levels. In conclusion, the results suggest ADAM10 alleviates symptoms of sodium laurate-induced TAO in rats via the RAGE/NF-κB signaling pathway and provides insight into the molecular basis and a potential therapeutic strategy for TAO.

Background Aorto-left ventricular tunnel (ALVT) is a rare congenital extracardiac channel that connects the ascending aorta to the left ventricle. To our knowledge, no case has been thus far reported as ALVT with both anomalous origin of right coronary artery (AORCA) and bicuspid aortic valve (BAV). Case presentation We reported a case of a 5-year-old female diagnosed as ALVT with accompanying AORCA and BAV which had been previously misdiagnosed as aortic regurgitation (AR) triggered by BAV. Additionally, a special modality of ALVT was confirmed in this case during the surgery in which the tunnel was formed by the separation between the roots of two aortic leaflets during the diastolic period. Conclusions ALVT with both AORCA and BAV is clinically uncommon and the aberrant tunnel in ALVT can be formed by the gap between the roots of two aortic leaflets. Besides, ALVT with BAV might easily lead to an inaccurate diagnose as aortic regurgitation caused by BAV. Cardiac surgeons should be alerted for differential diagnosis of ALVT with BAV and isolated bicuspid aortic valve (BAV) causing aortic regurgitation (AR).

DNA methyltransferase-1 (DNMT1) plays a crucial role in the maintenance of genomic methylation patterns. The crystal structure of DNMT1 was determined in two different states in which the helix that follows the catalytic loop was either kinked (designated helix-kinked) or well folded (designated helix-straight state). Here, we show that the proper structural transition between these two states is required for DNMT1 activity. The mutations of N1248A and R1279D, which did not affect interactions between DNMT1 and substrates or cofactors, allosterically reduced enzymatic activities in vitro by decreasing k(cat)/K(m) for AdoMet. The crystallographic data combined with molecular dynamic (MD) simulations indicated that the N1248A and R1279D mutants bias the catalytic helix to either the kinked or straight conformation. In addition, genetic complementation assays for the two mutants suggested that disturbing the conformational transition reduced DNMT1 activity in cells, which could act additively with existing DNMT inhibitors to decrease DNA methylation. Collectively, our studies provide molecular insights into conformational changes of the catalytic helix, which is essential for DNMT1 catalytic activity, and thus aid in better understanding the relationship between DNMT1 dynamic switching and enzymatic activity.

In this paper, the spectral characteristics of the interaction between lead and bovine serum albumin (BSA) were analyzed by fluorescence spectroscopy, ultraviolet spectroscopy and infrared spectroscopy. The effects of pH, bovine serum albumin concentration, lead ion concentration and ionic strength on the spectra of lead ion-bovine serum albumin system were investigated, and the best testing condition is to determine the interaction between lead and BSA by testing the peak changes or displacement in the UV spectrum analysis. Fluorescence spectroscopy showed that lead ion could induce the fluorescence quenching of bovine serum albumin. The influence of lead ion on the secondary structure of protein was analyzed by infrared spectroscopy. It was found that β-angle increased, α-helix decreased and β-slice increased.

The POU family transcription factor Oct4 plays pivotal roles in regulating pluripotency and somatic cell reprogramming. Previous studies have indicated an important role for major groove contacts in Oct4-DNA recognition; however, the contributions of the RK motif in the POUh domain and the linker segment joining the two DNA-binding domains remain poorly understood. Here, by combining molecular modelling and functional assays, we find that the RK motif is essential for Oct4-DNA association by recognizing the narrowed DNA minor groove. Intriguingly, computational simulations reveal that the function of the RK motif may be finely tuned by H-bond interactions with the partially disordered linker segment and that breaking these interactions significantly enhances the DNA binding and reprogramming activities of Oct4. These findings uncover a self-regulatory mechanism for specific Oct4-DNA recognition and provide insights into the functional crosstalk at the molecular level that may illuminate mechanistic studies of the Oct protein family and possibly transcription factors in the POU family. Our gain-of-function Oct4 mutants might also be useful tools for use in reprogramming and regenerative medicine.

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.

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.

Cdk5 is a member of cyclin-dependent kinase (Cdk), a proline-directed serine/threonine kinase, and plays a key role in normal neural development and function. Evidence of previous study showed that chronic inhibition of Cdk5 in hippocampal dentate gyrus (DG) blocked the development of depressive-like symptoms, suggesting that Cdk5 plays a role in development of depression. Forced swim test, novelty-suppressed feeding test, and learned helplessness were used to evaluate the cellular and molecular mechanisms underlying the behavioral regulation of Cdk5 inhibitors in rats. Two Cdk5 inhibitors butyrolactone and roscovitine were used to investigate the possible antidepressant-like actions of Cdk5 blockade and the potential mechanisms. Systemic administration of butyrolactone (200 mg/kg, IP) or roscovitine (100 mg/kg, IP) produced effective antidepressant-like actions. Moreover, infusion (5 mM) of GSK3β activator LY294002 into DG abolished the antidepressant-like actions of butyrolactone and roscovitine, suggesting that inhibition of GSK3β might be involved in the antidepressant effect of Cdk5 inhibitors. Moreover, pretreatment of LY294002 (5 mM) blocked the antidepressant-like effect of butyrolactone and roscovitine in learned helplessness. Additionally, inescapable footshock induced a significant increase of GSK3β activity, while butyrolactone and roscovitine decreased GSK3β activity. In contrast, pretreatment of LY294002 prevented the inhibitory effects of butyrolactone and roscovitine on GSK3β activation. Finally, a specific GSK3β inhibitor, SB216763 (1 ng, DG), demonstrated an effective antidepressant-like action. These findings demonstrate that systemic administration of Cdk5 inhibitors produced antidepressant-like actions and that inhibition of GSK3β is involved in behavioral response of Cdk5 inhibitors.

Activating mutations in KIT have been associated with gastrointestinal stromal tumors (GISTs). The tyrosine kinase inhibitor imatinib mesylate has revolutionized the treatment of GISTs. Unfortunately, primary or acquired resistance to imatinib does occur in GISTs and forms a major problem. Although sunitinib malate, a multi-kinase inhibitor, has shown effectiveness against imatinib-resistant GISTs, recent studies have indicated that some imatinib-resistant GISTs harboring secondary mutations in the KIT activation loop were also resistant to sunitinib. Therefore, new drugs capable of overcoming the dual drug resistance of GISTs probably have potential clinical utility. In this study, we investigated the efficacy of flumatinib, an inhibitor of BCR-ABL/PDGFR/KIT, against 32D cells transformed by various KIT mutants and evaluated its potency to overcome the drug resistance of certain mutants. Interestingly, our in vitro study revealed that flumatinib effectively overcame the drug resistance of certain KIT mutants with activation loop mutations (i.e., D820G, N822K, Y823D, and A829P). Our in vivo study consistently suggested that flumatinib had superior efficacy compared with imatinib or sunitinib against 32D cells with the secondary mutation Y823D. Molecular modeling of flumatinib docked to the KIT kinase domain suggested a special mechanism underlying the capability of flumatinib to overcome the drug-resistance conferred by activation loop mutations. These findings suggest that flumatinib could be a promising therapeutic agent against GISTs resistant to both imatinib and sunitinib because of secondary mutations in the activation loop.

Reversing the DNA methylation abnormalities by targeting the maintenance DNA methylation machinery represents a sought-after therapy paradigm in both liquid and solid tumors. UHRF1, a multi-domain protein with both chromatin reader and writer functions, is essential for targeting DNA methyltransferase 1 (DNMT1) to replicating DNA to maintain DNA methylation in both normal and cancer cells. Dysregulation of the DNMT1-UHRF1 axis is being increasingly linked to malignant transformation and progression across cancer types. Our recent study shows that UHRF1 depletion, alone or in combination with low doses of a DNMT inhibitor, effectively induces DNA demethylation and tumor suppressor genes (TSGs) reactivation. These findings collectively suggest UHRF1 represents a promising target for developing next-generation DNA demethylation agents for cancer therapy. Understanding the collective contribution of UHRF1’s domains for maintenance methylation is essential for the major translational goal of blocking maintenance of abnormal DNA methylation in established cancers and throughout cancer initiation and progression. While the UHRF1 domains responsible for de novo or re-methylation have been identified, the domain requirements specifically for maintaining normal and cancer-specific DNA methylation are poorly characterized. Herein, by developing a carefully timed genetic complementation assay, we systematically interrogate the roles for each major domain of UHRF1 for maintaining genome-wide DNA methylation in human colorectal cancer (CRC) cells. Distinct from the domain required for establishing methylation, we find that UHRF1 histone-binding and hemimethylated DNA reader domains, but not E3 ligase activity, are essential for maintaining cancer-specific DNA methylation in both HCT116 and RKO cells. Disrupting either one of the essential domains phenocopies UHRF1 depletion for global DNA demethylation and reactivation of epigenetically silenced TSGs. Supporting the essential roles of abnormal DNA methylation in sustaining the key oncogenic properties of CRC cells, we further show genetic perturbation of either histone- or hemimethylated DNA-binding activities of UHRF1 dramatically impairs CRC proliferation, invasion, and metastasis in vitro and in vivo. Moreover, for eight UHRF1 chromatin-reader domain regulated TSGs, we reveal a strong negative correlation between high UHRF1 expression, promoter hypermethylation, and their low expression with disease progression and overall survival in CRC patients in both TCGA and two independent CRC cohorts (n=363 and 390, respectively). Taken together, our data identify important differences from domains dominant for de novo DNA methylation, and provide important implications for the oncogenic functions of UHRF1 in CRC, and for credentialing UHRF1 as a desirable target for cancer drug development and means to personalize this. Citation Format: Xiangqian Kong, Jie Chen, Wenbing Xie, Stephen M. Brown, Yi Cai, Kaichun Wu, Daiming Fan, Yongzhan Nie, Yong Tao, Ray-Whay Chiu Yen, Hariharan Easwaran, Michael J. Topper, Scott B. Rothbart, Limin Xia, Stephen B. Baylin. Defining UHRF1 domains that support maintenance of human colon cancer DNA methylation and tumorigenicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 947.

Epigenetics is key to understanding modulation of gene expression at specific stages and conditions in nervous system development and function. In epigenetic processes, a variety of enzymes contribute to modify chromatin with methyl, acetyl or other chemical marks, leading to repression or activation of the targeted gene without altering the original sequence. Aberrant activities of these epigenetic enzymes are implicated in many nervous system diseases, including neurodevelopmental disorders, brain cancer, neurodegenerative diseases, and mental illnesses. Thus, they have emerged as new targets for treating a variety of nervous system disorders. In this review, we briefly summarize the association between various epigenetic mechanisms and discuss recent progress in drug discovery efforts involving epigenetic regulators.

New Delhi metallo-β-lactamase-1 (NDM-1) has emerged as a major global threat to human health for its rapid rate of dissemination and ability to make pathogenic microbes resistant to almost all known β-lactam antibiotics. In addition, effective NDM-1 inhibitors have not been identified to date. In spite of the plethora of structural and kinetic data available, the accurate molecular characteristics of and details on the enzymatic reaction of NDM-1 hydrolyzing β-lactam antibiotics remain incompletely understood. In this study, a combined computational approach including molecular docking, molecular dynamics simulations and quantum mechanics/molecular mechanics calculations was performed to characterize the catalytic mechanism of meropenem catalyzed by NDM-1. The quantum mechanics/molecular mechanics results indicate that the ionized D124 is beneficial to the cleavage of the C-N bond within the β-lactam ring. Meanwhile, it is energetically favorable to form an intermediate if no water molecule coordinates to Zn2. Moreover, according to the molecular dynamics results, the conserved residue K211 plays a pivotal role in substrate binding and catalysis, which is quite consistent with previous mutagenesis data. Our study provides detailed insights into the catalytic mechanism of NDM-1 hydrolyzing meropenem β-lactam antibiotics and offers clues for the discovery of new antibiotics against NDM-1 positive strains in clinical studies.

Reversing DNA methylation abnormalities and associated gene silencing, through inhibiting DNA methyltransferases (DNMTs) is an important potential cancer therapy paradigm. Maximizing this potential requires defining precisely how these enzymes maintain genome-wide, cancer-specific DNA methylation. To date, there is incomplete understanding of precisely how the three DNMTs, 1, 3A, and 3B, interact for maintaining DNA methylation abnormalities in cancer. By combining genetic and shRNA depletion strategies, we define not only a dominant role for DNA methyltransferase 1 (DNMT1) but also distinct roles of 3A and 3B in genome-wide DNA methylation maintenance. Lowering DNMT1 below a threshold level is required for maximal loss of DNA methylation at all genomic regions, including gene body and enhancer regions, and for maximally reversing abnormal promoter DNA hypermethylation and associated gene silencing to reexpress key genes. It is difficult to reach this threshold with patient-tolerable doses of current DNMT inhibitors (DNMTIs). We show that new approaches, like decreasing the DNMT targeting protein, UHRF1, can augment the DNA demethylation capacities of existing DNA methylation inhibitors for fully realizing their therapeutic potential.

Vascular endothelial cell (VEC) apoptosis is involved in the development of atherosclerosis and other cardiovascular diseases. We previously found that ethyl 1-(2-hydroxy-3-aroxypropyl)-3-aryl-1H-pyrazole -5-carboxylate derivatives (3a-o) play important roles in cell fate control. In this study, among the 15 compounds, we further screened 2 compounds, 3d and 3k, that suppressed VEC apoptosis induced by deprivation of serum and fibroblast growth factor 2. To clarify which chiral enantiomers of 3d and 3k functioned, we synthesized 3d-S and its enantiomer 3d-R, 3k-S, and its enantiomer 3k-R. Then, we investigated the apoptosis-inhibiting activity of the chiral compounds in VECs. Four small molecules, 3d-S, 3d-R, 3k-S, 3k-R, significantly elevated VEC viability and inhibited apoptosis. Furthermore, these small molecules could obviously decrease the level of integrin β4 that plays a key role in the regulation of VEC apoptosis. 3k-S and 3k-R increased Bcl-2/Bax ratio and reduced reactive oxygen species levels dramatically. Therefore, we provide new VEC apoptosis inhibitors. These compounds may be potential agents in the prevention of vascular diseases associated with VEC apoptosis.

Oxidation sensing and quorum sensing significantly affect bacterial physiology and host–pathogen interactions. However, little attention has been paid to the cross-talk between these two seemingly orthogonal signaling pathways. Here we show that the quorum-sensing agr system has a built-in oxidation-sensing mechanism through an intramolecular disulfide switch possessed by the DNA-binding domain of the response regulator AgrA. Biochemical and mass spectrometric analysis revealed that oxidation induces the intracellular disulfide bond formation between Cys-199 and Cys-228, thus leading to dissociation of AgrA from DNA. Molecular dynamics (MD) simulations suggest that the disulfide bond formation generates a steric clash responsible for the abolished DNA binding of the oxidized AgrA. Mutagenesis studies further established that Cys-199 is crucial for oxidation sensing. The oxidation-sensing role of Cys-199 is further supported by the observation that the mutant Staphylococcus aureus strain expressing AgrAC199S is more susceptible to H 2 O 2 owing to repression of the antioxidant bsaA gene under oxidative stress. Together, our results show that oxidation sensing is a component of the quorum-sensing agr signaling system, which serves as an intrinsic checkpoint to ameliorate the oxidation burden caused by intense metabolic activity and potential host immune response.

Recent breakthroughs in generating induced pluripotent stem cells (iPSCs) using four defined factors have revealed the potential utility of stem cells in biological research and clinical applications. However, the low efficiency and slow kinetics of reprogramming related to producing these cells and underlying safety issues, such as viral integration and genetic and epigenetic abnormalities of iPSCs, hamper the further application of iPSCs in laboratory and clinical settings. Previous studies have suggested that reprogramming efficiency can be enhanced and that reprogramming kinetics can be accelerated by manipulating epigenetic status. Herein, we review recent studies on the application of epigenome-modifying small molecules in enhancing reprogramming and functionally replacing some reprogramming factors. We mainly focus on studies that have used small molecules to interfere with epigenome-modifying enzymes, such as DNA methyltransferase, histone acetyltransferase, and histone methyltransferase. The potential use of these small molecules in inducing iPSCs and new ways to identify small molecules of higher potency and fewer side effects are also discussed.

The receptor tyrosine kinase c-Met is an attractive target for therapeutic treatment of cancers nowadays. The discovery of small molecule inhibitors is of special interest in the blockade of the c-Met kinase pathway. Here, we initiated our study from compound 1a, a novel inhibitor against c-Met kinase. A substructure similarity search against the SPECS database and chemical synthesis methods were performed to obtain a series of pyrazolidine-3,5-dione derivatives. Through the enzyme-based assay against c-Met kinase, 4 compounds (1c, 1e, 1m and 1o) showed potential inhibitory activity, with IC(50) values mostly less than 10 μM. Based on the structure-activity relationship (SAR) and binding mode analysis, a focused combinatorial library was designed by the LD1.0 program. Taking into account ADMET properties and synthesis accessibility, seven candidate compounds (5a-g) were successfully synthesized. The activity of the most potent compounds 5b (IC(50) = 0.46 μM) was 20 fold higher than that of the lead 1a. Taken together, our findings identified the pyrazolidine-3,5-dione derivatives as potent inhibitors against c-Met kinase and demonstrated the efficiency of the strategy in the development of small molecules against c-Met kinase.

A series of substituted 5-benzyl-2-phenylpyrazolo[1,5-a]pyrazin-4,6(5H,7H)-dione derivatives was synthesized by one-step reaction of ethyl 3-phenyl-1H-pyrazole-5-carboxylate derivatives and N-arylalkyl-2-chloroacetamide. Structures of the compounds were determined by IR, (1)H NMR and mass spectroscopy. In addition, a representative single-crystal structure was characterized by using X-ray diffraction analysis. The compound 5j could selectively inhibit the growth of H322 lung cancer cells which contain a mutated p53 gene in a dose-dependent manner through inducing apoptosis of cells.