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1.
Medicine (Baltimore) ; 103(13): e37586, 2024 Mar 29.
Article in English | MEDLINE | ID: mdl-38552094

ABSTRACT

OBJECTIVE: The development and current state of hemorrhagic fever with renal syndrome (HFRS) over the past 40 years are analyzed in this study, along with explored and discovered the hotspots and frontiers in the field, which serve as the foundation for future investigation. METHODS: CiteSpace and VOSviewer analysis software were used to visually analyze the literature data on HFRS from 1980 to 2022, including the annual number of publications, countries and research institutions, authors, co-cited literature and keywords. RESULTS: The number of pertinent papers published in the field of HFRS displayed an overall upward trend from 1980 to 2022. The United States, China, Germany, Sweden, and France are the top 5 countries in terms of publishing volume, with high intermediate centrality mainly concentrated in Europe and the United States. The top 10 co-occurring keywords were hemorrhagic fever, renal syndrome, infection, virus, epidemic, nephropathia epidemical, disease, hantavirus, outbreak, and transmission. According to keyword cluster analysis, there were 4 main research fields. In the HFRS-related study, there were mainly 21 notable keywords and "Korean hemorrhagic fever" had the highest hemorrhagic value (28.87). CONCLUSION: The United States, China, Germany, Sweden and other countries attached great importance to the HFRS-related research. Moreover, the collaboration between authors and institutions in various collaborator clusters should be strengthened. In recent decades, investigations have focused on the study of viral infection and the clinical symptoms and pathophysiology of HFRS. Future research may concentrate on factors affecting host population distribution and density, such as vaccine development and meteorological factors pertaining to virus transmission.


Subject(s)
Hemorrhagic Fever with Renal Syndrome , Humans , Hemorrhagic Fever with Renal Syndrome/epidemiology , Europe , China/epidemiology , Germany , France
2.
Acta Pharmacol Sin ; 44(7): 1500-1518, 2023 Jul.
Article in English | MEDLINE | ID: mdl-36639570

ABSTRACT

As a major class of medicine for treating the lethal type of castration-resistant prostate cancer (PCa), long-term use of androgen receptor (AR) antagonists commonly leads to antiandrogen resistance. When AR signaling pathway is blocked by AR-targeted therapy, glucocorticoid receptor (GR) could compensate for AR function especially at the late stage of PCa. AR-GR dual antagonist is expected to be a good solution for this situation. Nevertheless, no effective non-steroidal AR-GR dual antagonist has been reported so far. In this study, an AR-GR dual binder H18 was first discovered by combining structure-based virtual screening and biological evaluation. Then with the aid of computationally guided design, the AR-GR dual antagonist HD57 was finally identified with antagonistic activity towards both AR (IC50 = 0.394 µM) and GR (IC50 = 17.81 µM). Moreover, HD57 could effectively antagonize various clinically relevant AR mutants. Further molecular dynamics simulation provided more atomic insights into the mode of action of HD57. Our research presents an efficient and rational strategy for discovering novel AR-GR dual antagonists, and the new scaffold provides important clues for the development of novel therapeutics for castration-resistant PCa.


Subject(s)
Androgen Antagonists , Prostatic Neoplasms , Male , Humans , Androgen Antagonists/pharmacology , Receptors, Glucocorticoid/metabolism , Receptors, Androgen/metabolism , Androgen Receptor Antagonists/pharmacology , Prostatic Neoplasms/metabolism , Cell Line, Tumor
3.
J Med Chem ; 65(3): 2507-2521, 2022 02 10.
Article in English | MEDLINE | ID: mdl-35077161

ABSTRACT

Androgen receptor (AR) antagonists have been widely used for the treatment of prostate cancer (PCa). As a link between the AR and its transcriptional function, the activation function 2 (AF2) region has recently been revealed as a novel targeting site for developing AR antagonists. Here, we reported a series of N-(4-(benzyloxy)-phenyl)-sulfonamide derivatives as new-scaffold AR antagonists targeting the AR AF2. Therein, compound T1-12 showed excellent AR antagonistic activity (IC50 = 0.47 µM) and peptide displacement activity (IC50 = 18.05 µM). Furthermore, the in vivo LNCaP xenograft study confirmed that T1-12 offered effective inhibition on tumor growth when administered intratumorally. The study represents the first successful attempt to identify a small molecule targeting the AR AF2 with submicromolar AR antagonistic activity by structure-based virtual screening and provides important clues for the development of novel therapeutics for PCa treatment.


Subject(s)
Androgen Receptor Antagonists/therapeutic use , Antineoplastic Agents/therapeutic use , Prostatic Neoplasms/drug therapy , Receptors, Androgen/metabolism , Sulfonamides/therapeutic use , Androgen Receptor Antagonists/chemical synthesis , Androgen Receptor Antagonists/metabolism , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/metabolism , Binding Sites , Cell Proliferation/drug effects , Gene Expression/drug effects , Humans , Male , Mice, SCID , Molecular Docking Simulation , Molecular Structure , Protein Transport/drug effects , Receptors, Androgen/chemistry , Structure-Activity Relationship , Sulfonamides/chemical synthesis , Sulfonamides/metabolism , Xenograft Model Antitumor Assays
4.
Acta Pharmacol Sin ; 43(1): 229-239, 2022 Jan.
Article in English | MEDLINE | ID: mdl-33767381

ABSTRACT

Androgen receptor (AR), a ligand-activated transcription factor, is a master regulator in the development and progress of prostate cancer (PCa). A major challenge for the clinically used AR antagonists is the rapid emergence of resistance induced by the mutations at AR ligand binding domain (LBD), and therefore the discovery of novel anti-AR therapeutics that can combat mutation-induced resistance is quite demanding. Therein, blocking the interaction between AR and DNA represents an innovative strategy. However, the hits confirmed targeting on it so far are all structurally based on a sole chemical scaffold. In this study, an integrated docking-based virtual screening (VS) strategy based on the crystal structure of the DNA binding domain (DBD) of AR was conducted to search for novel AR antagonists with new scaffolds and 2-(2-butyl-1,3-dioxoisoindoline-5-carboxamido)-4,5-dimethoxybenzoicacid (Cpd39) was identified as a potential hit, which was competent to block the binding of AR DBD to DNA and showed decent potency against AR transcriptional activity. Furthermore, Cpd39 was safe and capable of effectively inhibiting the proliferation of PCa cell lines (i.e., LNCaP, PC3, DU145, and 22RV1) and reducing the expression of the genes regulated by not only the full-length AR but also the splice variant AR-V7. The novel AR DBD-ARE blocker Cpd39 could serve as a starting point for the development of new therapeutics for castration-resistant PCa.


Subject(s)
Androgen Receptor Antagonists/pharmacology , DNA/antagonists & inhibitors , Drug Discovery , Molecular Docking Simulation , Receptors, Androgen/metabolism , Androgen Receptor Antagonists/chemistry , Binding Sites/drug effects , DNA/chemistry , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Humans , Molecular Structure , Receptors, Androgen/chemistry , Structure-Activity Relationship
5.
Acta Biochim Biophys Sin (Shanghai) ; 52(4): 421-429, 2020 Apr 20.
Article in English | MEDLINE | ID: mdl-32250393

ABSTRACT

Local hypoxia is a universal phenomenon in most solid tumors. The role of local hypoxia in the tumor microenvironment and cancer growth and metastasis has been well established. However, the effect of acute systemic hypoxia (exposing the whole body to 10% O2 environment) on cancer has not yet been investigated. In this study, we investigated the potential effects of acute systemic hypoxia itself and in combination with metformin on hepatocellular carcinoma (HCC) growth and metastasis in a mouse model of HCC. Acute systemic hypoxia significantly decreased tumor volume and weight in H22 tumor-bearing mice. Interestingly, the combined treatment of acute systemic hypoxia and metformin showed a more pronounced effect in reducing tumor volume and weight. Moreover, acute systemic hypoxia and metformin in combination had a potent inhibitory effect on tumor progression. More importantly, the expressions of hypoxia response genes including hypoxia-inducible factor-1 α, vascular endothelial growth factor, and matrix metalloproteinase 2 were significantly decreased in the tumor tissues with combination treatment. Our study demonstrated that acute systemic hypoxia repressed tumor progression of the HCC and potentiated the anti-tumor activities of metformin. This study supports that combination of systemic hypoxia and metformin treatment may represent a novel strategy for HCC.


Subject(s)
Carcinoma, Hepatocellular , Hypoxia , Liver Neoplasms , Metformin/pharmacology , Animals , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/pathology , Carcinoma, Hepatocellular/therapy , Cell Line, Tumor , Hypoxia/metabolism , Hypoxia/pathology , Liver Neoplasms/metabolism , Liver Neoplasms/pathology , Liver Neoplasms/therapy , Male , Mice , Mice, Inbred BALB C
6.
J Chem Inf Model ; 59(2): 842-857, 2019 02 25.
Article in English | MEDLINE | ID: mdl-30658039

ABSTRACT

Androgen receptor (AR), as a member of the nuclear receptor (NR) superfamily, regulates the gene transcription in response to the sequential binding of diverse agonists and coactivators. Great progress has been made in studies on the pharmacology and structure of AR, but the atomic level mechanism of the bidirectional communications between the ligand-binding pocket (LBP) and the activation function-2 (AF2) region of AR remains poorly understood. Therefore, in this study, molecular dynamics (MD) simulations and free energy calculations were carried out to explore the interactions among water, agonist (DHT) or antagonist (HFT), AR, and coactivator (SRC3). Upon the binding of an agonist (DHT) or antagonist (HFT), the LBP structure would transform to the agonistic or antagonistic state, and the conformational changes of the LBP would regulate the structure of the AF2 surface. As a result, the binding of the androgen DHT could promote the recruitment of the coactivator SRC3 to the AF2, and on the contrary, the binding of the antagonist HFT would induce a perturbation to the shape of the AF2 and then weaken its accommodating capability of the coactivators with the LXXLL motif. The simulation results illustrated that the DHT-AR binding affinity was enhanced by the association of the coactivator SRC3, which would reduce the conformational fluctuation of the AR-LBD and expand the size of the AR LBP. On the other hand, the coactivator-to-HFT allosteric pathway, which involves the SRC3, helix 3 (H3), helix 4 (H4), the loop (L1-3) between helix 1 (H1) and H3, and HFT, was characterized. The HFT's skewness and different interactions between HFT and the LBP were observed in the SRC3-present AR. The mutual communications between the AF2 surface and LBP, together with the processes involving the interplay of the ligand binding and coactivator recruitment events, would help in understanding the association of coactivators and rationally develop potent drugs to inhibit the activity of AR.


Subject(s)
Molecular Dynamics Simulation , Receptors, Androgen/chemistry , Receptors, Androgen/metabolism , Amino Acid Motifs , Amino Acid Sequence , Binding Sites , Ligands , Nuclear Receptor Coactivator 3/metabolism , Protein Binding , Thermodynamics
7.
Med Res Rev ; 39(5): 1485-1514, 2019 09.
Article in English | MEDLINE | ID: mdl-30569509

ABSTRACT

Androgen receptor (AR) is closely associated with a group of hormone-related diseases including the cancers of prostate, breast, ovary, pancreas, etc and anabolic deficiencies such as muscle atrophy and osteoporosis. Depending on the specific type and stage of the diseases, AR ligands including not only antagonists but also agonists and modulators are considered as potential therapeutics, which makes AR an extremely interesting drug target. Here, we at first review the current understandings on the structural characteristics of AR, and then address why and how AR is investigated as a drug target for the relevant diseases and summarize the representative antagonists and agonists targeting five prospective small molecule binding sites at AR, including ligand-binding pocket, activation function-2 site, binding function-3 site, DNA-binding domain, and N-terminal domain, providing recent insights from a target and drug development view. Further comprehensive studies on AR and AR ligands would bring fruitful information and push the therapy of AR relevant diseases forward.


Subject(s)
Receptors, Androgen/drug effects , Binding Sites , Humans , Male , Prostatic Neoplasms/metabolism , Protein Conformation , Receptors, Androgen/chemistry , Receptors, Androgen/metabolism
8.
J Chem Inf Model ; 58(8): 1652-1661, 2018 08 27.
Article in English | MEDLINE | ID: mdl-29993249

ABSTRACT

The androgen receptor (AR) plays important roles in gene expression regulation, sexual phenotype maintenance, and prostate cancer (PCa) development. The communications between the AR ligand-binding domain (LBD) and its coactivator are critical to the activation of AR. It is still unclear how the ligand binding would affect the AR-coactivator interactions. In this work, the effects of the ligand binding on the AR-coactivator communications were explored by molecular dynamics (MD) simulations. The results showed that the ligand binding regulates the residue interactions in the function site AF-2. The ligand-to-coactivator allosteric pathway, which involves the coactivator, helix 3 (H3), helix 4 (H4), the loop between H3 and H4 (L3), and helix 12 (H12), and ligands, was characterized. In addition, the interactions of residues on the function site BF-3, especially on the boundary of AF-2 and BF-3, are also affected by the ligands. The MM/GBSA free energy calculations demonstrated that the binding affinity between the coactivator and apo-AR is roughly weaker than those between the coactivator and antagonistic ARs but stronger than those between the coactivator and agonistic ARs. The results indicated that the long-range electrostatic interactions and the conformational entropies are the main factors affecting the binding free energies. In addition, the F876L mutation on AR-LBD affects the ligand-to-coactivator allosteric pathway, which could be the reason for point mutation induced tolerance for the antagonistic drugs such as enzalutamide. Our study would help to develop novel drug candidates against PCa.


Subject(s)
Androgen Receptor Antagonists/pharmacology , Androgens/pharmacology , Receptors, Androgen/metabolism , Binding Sites/drug effects , Humans , Ligands , Molecular Docking Simulation , Molecular Dynamics Simulation , Protein Binding/drug effects , Protein Conformation/drug effects , Receptors, Androgen/chemistry , Receptors, Androgen/genetics
9.
Genomics Proteomics Bioinformatics ; 16(6): 416-427, 2018 12.
Article in English | MEDLINE | ID: mdl-30639122

ABSTRACT

Androgen receptor (AR) is a ligand-activated transcription factor that plays a pivotal role in the development and progression of many severe diseases such as prostate cancer, muscle atrophy, and osteoporosis. Binding of ligands to AR triggers the conformational changes in AR that may affect the recruitment of coactivators and downstream response of AR signaling pathway. Therefore, AR ligands have great potential to treat these diseases. In this study, we searched for novel AR ligands by performing a docking-based virtual screening (VS) on the basis of the crystal structure of the AR ligand binding domain (LBD) in complex with its agonist. A total of 58 structurally diverse compounds were selected and subjected to LBD affinity assay, with five of them (HBP1-3, HBP1-17, HBP1-38, HBP1-51, and HBP1-58) exhibiting strong binding to AR-LBD. The IC50 values of HBP1-51 and HBP1-58 are 3.96 µM and 4.92 µM, respectively, which are even lower than that of enzalutamide (Enz, IC50 = 13.87 µM), a marketed second-generation AR antagonist. Further bioactivity assays suggest that HBP1-51 is an AR agonist, whereas HBP1-58 is an AR antagonist. In addition, molecular dynamics (MD) simulations and principal components analysis (PCA) were carried out to reveal the binding principle of the newly-identified AR ligands toward AR. Our modeling results indicate that the conformational changes of helix 12 induced by the bindings of antagonist and agonist are visibly different. In summary, the current study provides a highly efficient way to discover novel AR ligands, which could serve as the starting point for development of new therapeutics for AR-related diseases.


Subject(s)
Androgen Receptor Antagonists/pharmacology , Androgens/metabolism , Androgens/pharmacology , Drug Discovery/methods , Receptors, Androgen/metabolism , Benzamides , Biological Assay , Cell Line, Tumor , Humans , Ligands , Male , Molecular Docking Simulation , Molecular Dynamics Simulation , Nitriles , Phenylthiohydantoin/analogs & derivatives , Phenylthiohydantoin/pharmacology , Principal Component Analysis , Prostatic Neoplasms/drug therapy , Protein Binding/physiology , Protein Conformation/drug effects
10.
Phys Chem Chem Phys ; 20(8): 5591-5605, 2018 Feb 21.
Article in English | MEDLINE | ID: mdl-29270587

ABSTRACT

NIMA-related kinase 2 (Nek2) plays a significant role in cell cycle regulation, and overexpression of Nek2 has been observed in several types of carcinoma, suggesting it is a potential target for cancer therapy. In this study, we attempted to gain more insight into the binding mechanisms of a series of aminopyrazine inhibitors of Nek2 through multiple molecular modeling techniques, including molecular docking, molecular dynamics (MD) simulations and free energy calculations. The simulation results showed that the induced fit docking and ensemble docking based on multiple protein structures yield better predictions than conventional rigid receptor docking, highlighting the importance of incorporating receptor flexibility into the accurate predictions of the binding poses and binding affinities of Nek2 inhibitors. Additionally, we observed that the Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) calculations did not show better performance than the docking scoring to rank the binding affinities of the studied inhibitors, suggesting that MM/GBSA is system-dependent and may not be the best choice for the Nek2 systems. Moreover, the detailed information on protein-ligand binding was characterized by the MM/GBSA free energy decomposition, and a number of derivatives with improved docking scores were designed. It is expected that our study can provide valuable information for the future rational design of novel and potent inhibitors of Nek2.


Subject(s)
NIMA-Related Kinases/antagonists & inhibitors , Protein Kinase Inhibitors/pharmacology , Pyrazines/pharmacology , Humans , Ligands , Models, Molecular , Molecular Structure , NIMA-Related Kinases/metabolism , Protein Kinase Inhibitors/chemistry , Pyrazines/chemistry , Thermodynamics
11.
ACS Cent Sci ; 3(11): 1208-1220, 2017 Nov 22.
Article in English | MEDLINE | ID: mdl-29202023

ABSTRACT

Targeted inhibition of anaplastic lymphoma kinase (ALK) dramatically improved therapeutic outcomes in the treatment of ALK-positive cancers, but unfortunately patients invariably progressed due to acquired resistance mutations in ALK. Currently available drugs are all type-I inhibitors bound to the ATP-binding pocket and are most likely to be resistant in patients harboring genetic mutations surrounding the ATP pocket. To overcome drug resistance, we rationally designed a novel kind of "bridge" inhibitor, which specially bind into an extended hydrophobic back pocket adjacent to the ATP-binding site of ALK. The novel type-I1/2 inhibitors display excellent antiproliferation activity against ALK-positive cancer cells and appear superior to two clinically used drugs, crizotinib and ceritinib. Structural and molecular modeling analyses indicate that the inhibitor induces dramatic conformational transition and stabilizes unique DFG-shifted loop conformation, enabling persistent sensitivity to different genetic mutations in ALK. These data highlight a rationale for further development of next-generation ALK inhibitors to combat drug resistance.

12.
Mol Pharm ; 14(11): 3935-3953, 2017 11 06.
Article in English | MEDLINE | ID: mdl-29037046

ABSTRACT

Xenobiotic chemicals and their metabolites are mainly excreted out of our bodies by the urinary tract through the urine. Chemical-induced urinary tract toxicity is one of the main reasons that cause failure during drug development, and it is a common adverse event for medications, natural supplements, and environmental chemicals. Despite its importance, there are only a few in silico models for assessing urinary tract toxicity for a large number of compounds with diverse chemical structures. Here, we developed a series of qualitative and quantitative structure-activity relationship (QSAR) models for predicting urinary tract toxicity. In our study, the recursive feature elimination method incorporated with random forests (RFE-RF) was used for dimension reduction, and then eight machine learning approaches were used for QSAR modeling, i.e., relevance vector machine (RVM), support vector machine (SVM), regularized random forest (RRF), C5.0 trees, eXtreme gradient boosting (XGBoost), AdaBoost.M1, SVM boosting (SVMBoost), and RVM boosting (RVMBoost). For building classification models, the synthetic minority oversampling technique was used to handle the imbalance data set problem. Among all the machine learning approaches, SVMBoost based on the RBF kernel achieves both the best quantitative (qext2 = 0.845) and qualitative predictions for the test set (MCC of 0.787, AUC of 0.893, sensitivity of 89.6%, specificity of 94.1%, and global accuracy of 90.8%). The application domains were then analyzed, and all of the tested chemicals fall within the application domain coverage. We also examined the structure features of the chemicals with large prediction errors. In brief, both the regression and classification models developed by the SVMBoost approach have reliable prediction capability for assessing chemical-induced urinary tract toxicity.


Subject(s)
Drug Discovery , Machine Learning , Algorithms , Quantitative Structure-Activity Relationship , Support Vector Machine
13.
Environ Sci Technol ; 51(11): 6452-6460, 2017 Jun 06.
Article in English | MEDLINE | ID: mdl-28466639

ABSTRACT

Parabens have been widely used in packaged foods, pharmaceuticals, and personal-care products. Considering their potential hydrolysis, we herein investigated structural features leading to the disruption of human androgen receptor (AR) and whether hydrolysis could alleviate such effects using the recombinant yeast two-hybrid assay. Parabens with an aryloxy side chain such as benzyl paraben and phenyl paraben have the strongest antiandrogenic activity. The antiandrogenic activity of parabens with alkyloxyl side chains decreases as the side chain length increases from 1 to 4, and no antiandrogenic effect occurred for heptyl, octyl, and dodecyl parabens with the number of alkoxyl carbon atoms longer than 7. The antiandrogenic activity of parabens correlates significantly with their binding energies (R2 = 0.84, p = 0.01) and were completely diminished after the hydrolysis, particularly for parabens with aryloxy side chains. The Km for the hydrolysis of parabens with aromatic moiety side chain is 1 order of magnitude higher than that of the parabens with alkyl side chains. Both in vitro and in silico data, for the first time, suggest parabens with aromatic side chains are less prone to hydrolysis. Our results provide an insight into risk of various paraben and considerations for design of new paraben-related substitutes.


Subject(s)
Androgen Antagonists , Molecular Docking Simulation , Parabens/chemistry , Humans , Hydrolysis
14.
Sci Rep ; 6: 37628, 2016 11 23.
Article in English | MEDLINE | ID: mdl-27876862

ABSTRACT

The receptor tyrosine kinase Tie-2 is involved in vessel remodeling and maturation, and has been regarded as a potential target for the treatment of various solid tumors. The absence of novel, potent and selective inhibitors severely hampers the understanding of the therapeutic potential of Tie-2. In the present work, we describe the discovery of novel type-I inhibitors of Tie-2 by structure-based virtual screening. Preliminary SAR was also performed based on one active compound, and several novel inhibitors with low micro-molar affinity were discovered. To directly compare the efficiency between different filtering strategies in selecting VS candidates, two methods were separately carried out to screen the same chemical library, and the selected VS candidates were then experimentally assessed by in vitro enzymatic assays. The results demonstrate that the hit rate is improved when stricter drug-likeness criteria and less number of molecules for clustering analysis are used, and meanwhile, the molecular diversity of the compounds still maintains. As a case study of TIE-2, the information presented in this work underscores the importance of selecting an appropriate selection strategy in VS campaign, and the novel inhibitors identified and the detailed binding modes of action provide a starting point for further hit-to-lead optimization process.


Subject(s)
Computer Simulation , Drug Evaluation, Preclinical , Protein Kinase Inhibitors/pharmacology , Receptor, TIE-2/antagonists & inhibitors , User-Computer Interface , Inhibitory Concentration 50 , Molecular Docking Simulation , Protein Kinase Inhibitors/chemistry , Receptor, TIE-2/metabolism , Structure-Activity Relationship
15.
J Chem Theory Comput ; 12(9): 4611-9, 2016 Sep 13.
Article in English | MEDLINE | ID: mdl-27560203

ABSTRACT

Androgen receptor (AR) plays important roles in the development of prostate cancer (PCa). The antagonistic drugs, which suppress the activity of AR, are widely used in the treatment of PCa. However, the molecular mechanism of antagonism about how ligands affect the structures of AR remains elusive. To better understand the conformational variability of ARs bound with agonists or antagonists, we performed long time unbiased molecular dynamics (MD) simulations and enhanced sampling simulations for the ligand binding domain of AR (AR-LBD) in complex with various ligands. Based on the simulation results, we proposed an allosteric pathway linking ligands and helix 12 (H12) of AR-LBD, which involves the interactions among the ligands and the residues W741, H874, and I899. The interaction pathway provides an atomistic explanation of how ligands affect the structure of AR-LBD. A repositioning of H12 was observed, but it is facilitated by the C-terminal of H12, instead of by the loop between helix 11 (H11) and H12. The bias-exchange metadynamics simulations further demonstrated the above observations. More importantly, the free energy profiles constructed by the enhanced sampling simulations revealed the transition process between the antagonistic form and agonistic form of AR-LBD. Our results would be helpful for the design of more efficient antagonists of AR to combat PCa.


Subject(s)
Molecular Dynamics Simulation , Receptors, Androgen/chemistry , Allosteric Regulation , Androgen Receptor Antagonists/chemistry , Androgen Receptor Antagonists/metabolism , Ligands , Principal Component Analysis , Protein Binding , Protein Structure, Secondary , Protein Structure, Tertiary , Receptors, Androgen/metabolism
16.
J Chem Inf Model ; 55(12): 2693-704, 2015 Dec 28.
Article in English | MEDLINE | ID: mdl-26618892

ABSTRACT

Angiopoietin (ANG) ligands and their downstream TIE receptors have been validated as the second vascular signaling system involving vessel remodeling and maturation. Among them, the ANG/TIE-2 signaling pathway is involved in numerous life-threatening diseases and has become an attractive potential therapeutic target. Several large-molecule inhibitors targeting the ANG/TIE-2 axis have recently entered clinical phase for the therapy of various solid tumors, but selective small-molecule inhibitors of TIE-2 are still quite limited. In the present work, structure-based virtual screening was performed to search for type-I inhibitors of TIE-2. Of the only 41 compounds selected by our strategy, 8 molecules with the concentration of 25 µg/mL exhibit over 50% inhibitory rate against TIE-2 in in vitro enzymatic activity assay, and the IC50 values of 2 hits are lower than 1 µM. Further optimization and SAR analysis based on compound TP-S1-30 and 31 were carried out by using substructure searching strategy, leading to the discovery of several sub-100 nM inhibitors. Among them, the most potent compound, TP-S1-68, showed an inhibitory IC50 of 0.149 µM. These novel inhibitors of TIE-2 discovered in this study and the analogs of the active core scaffolds can serve as the starting points for further drug development.


Subject(s)
Drug Design , Molecular Docking Simulation , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Receptor, TIE-2/antagonists & inhibitors , Biological Assay , Crystallography, X-Ray , Dose-Response Relationship, Drug , Enzyme Activation/drug effects , Inhibitory Concentration 50 , Receptor, TIE-2/chemistry , Receptor, TIE-2/metabolism , Structure-Activity Relationship
17.
Article in Chinese | MEDLINE | ID: mdl-22934426

ABSTRACT

OBJECTIVE: To research the responsibility and mechanism of auditory event-related potentials (AERP) evoked by pure-tone and different Chinese speech (including single-syllable words, two-syllable words and munbers) stimuli respectively. Meanwhile, to explore feasibility of using different Chinese speech forms as stimulation to evoke AERP in Chinese people. METHOD: AERPs were measured in 37 young normal post-graduated students (70 ears) with pure-tone and three different Chinese speech forms as stimuli. The mean incidence rates, latencies and amplitudes of AERPs were analyzed, the waveforms of AERPs were quantitatively scored. Then all data were statistically analyzed and compared. RESULT: The typical wave P1, N1, P2, N2 and P3 of AERPs could be recorded by both pure-tone and three different Chinese speech stimuli, in which the Chinese two-syllable word was most likely to evoked AERP than pure-tone and remains of Chinese speech forms, and the differences were statistical significance (Chi2 = 0.046, P < 0.05). The quantitative scores and amplitudes of P3 evoked by pure-tone and three different Chinese speech stimuli were analyzed in 56 ears, whose results showed no significant difference (P > 0.05) among different stimuli. However, the waveforms of AERPs were smoother and much satisfied evoked by Chinese character and two-syllable word than pure-tone and Chinese number stimuli. The latencies of P3 evoked by number stimulus were significant longer than by other stimuli (P < 0.05). Nevertheless, the latencies of P3 were no significant differences among the other stimuli (P > 0.05). CONCLUSION: Besides pure-tone and Chinese single-syllable words, other Chinese speech such as two-syllable words and numbers could be used to evoke AERP with satisfied waveform, which indicated that the Chinese character, two-syllable words and numbers were available to apply for AERP measurement as stimuli for Chinese people.


Subject(s)
Evoked Potentials, Auditory/physiology , Speech/physiology , Adult , Asian People , Audiometry, Pure-Tone/methods , Evoked Potentials , Feasibility Studies , Female , Humans , Language , Male
18.
Anal Chim Acta ; 686(1-2): 1-8, 2011 Feb 07.
Article in English | MEDLINE | ID: mdl-21237303

ABSTRACT

An ion chromatographic method with on-line sample pretreatment was developed for the trace analysis of seven common anions in concentrated matrices. The pretreatment column used in this study consisted of polystyrene-divinylbenzene (PS-DVB) and multi-walled carbon nanotubes (MWCNTs). It was too hydrophobic to retain different inorganic anions, but it showed a strong affinity for organic compounds. Thus, this chromatographic system could be used to detect trace anions in organic solvents, organic acids and relevant salts. The addition of MWCNTs decreased the surface areas of stationary phases and the retention times of organic matrices were shortened. Compared with conventional column-switching technique, only a single instrument (ICS2100) was needed in this system, including a pump, a conductivity detector, an eluent generator, a six-port valve and a ten-port valve. An electrochemical self-generating suppressor (ESGS) was adopted to convert the eluent of KOH into water for the matrix elimination. Two different eluent were employed in the chromatographic system, one for separation and the other for matrix elimination. The sample pretreatment and analysis were realized simultaneously. After optimization of this system, a calibration study was conducted by preparing and analyzing eight concentrations (between 5 and 5000 µg L(-1)) of mixture standards of seven anions in deionized water. The linearity was between 0.9990 and 0.9998, and the detection limits ranged from 0.41 to 3.17 µg L(-1). A spiking study was performed on three representative organic chemicals with satisfactory recoveries between 88.1% and 118.5% when the concentrations of the matrices did not exceed 10 g L(-1).


Subject(s)
Chromatography, Ion Exchange/methods , Nanotubes, Carbon/chemistry , Organic Chemicals/analysis , Polystyrenes/chemistry , Vinyl Compounds/chemistry , Anions/analysis , Nanotubes, Carbon/ultrastructure , Solvents/chemistry
19.
Talanta ; 82(4): 1439-47, 2010 Sep 15.
Article in English | MEDLINE | ID: mdl-20801353

ABSTRACT

A polymer-based chromatographic stationary phase with embedded or grafted multi-walled carbon nanotubes (MWCNTs) has been developed. Three different synthetic methods were utilized to combine the nano-fibers with the substrate of polystyrene-divinylbenzene (PS-DVB). After optimizing the synthetic conditions, this novel polystyrene-divinylbenzene-carbon nanotube (PS-DVB-CNT) stationary phase was characterized by scanning electron microscopy, Raman spectroscopy, thermogravimetric analysis, chemical adsorption and desorption measurement, and mechanical stability test. Compared to PS-DVB particles, PS-DVB-CNT particles have certain improvement in physical and chromatographic performances because the addition of MWCNTs has altered the structures of the particles. The novel stationary phase owns satisfactory resolution, wide pH endurance, and long lifetime, which can be used as an extent to normal HPLC.

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