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1.
Biomed Pharmacother ; 165: 115261, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37549461

ABSTRACT

Enhancing the clearance of proteins associated with Alzheimer's disease (AD) emerges as a promising approach for AD therapeutics. This study explores the potential of Radix Stellariae, a traditional Chinese medicine, in treating AD. Utilizing transgenic C. elegans models of AD, we demonstrated that a 75% ethanol extract of Radix Stellariae (RSE) (at 50 µg/mL) effectively diminishes Aß and Tau protein expression, and alleviates their induced impairments including paralysis, behavioral dysfunction, neurotoxicity, and ROS accumulation. Additionally, RSE enhances the stress resistance of C. elegans. Further investigations revealed that RSE promotes autophagy, a critical cellular process for protein degradation, in these models. We found that inhibiting autophagy-related genes negated the neuroprotective effects of RSE, suggesting a central role for autophagy in the actions of RSE. In PC-12 cells, we observed that RSE not only inhibited Aß fibril formation but also promoted the degradation of AD-related proteins and reduced their cytotoxicity. Mechanistically, RSE was found to induce autophagy via modulating PI3K/AKT/mTOR and AMPK/mTOR signaling pathways. Importantly, inhibiting autophagy counteracted the beneficial effects of RSE on the clearance of AD-associated proteins. Moreover, we identified Dichotomine B, a ß-carboline alkaloid, as a key active constituent of RSE in mitigating AD pathology in C. elegans at concentrations ranging from 50 to 1000 µM. Collectively, our study presents novel discoveries that RSE alleviates AD pathology and toxicity primarily by inducing autophagy, both in vivo and in vitro. These findings open up new avenues for exploring the therapeutic potential of RSE and its active component, Dichotomine B, in treating neurodegenerative diseases like AD.


Subject(s)
Alzheimer Disease , Animals , Alzheimer Disease/metabolism , Caenorhabditis elegans/metabolism , Phosphatidylinositol 3-Kinases , Autophagy , TOR Serine-Threonine Kinases , Amyloid beta-Peptides/metabolism , Disease Models, Animal
2.
Phytother Res ; 37(10): 4639-4654, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37394882

ABSTRACT

BACKGROUND: Alzheimer's disease (AD) is a prevalent neurodegenerative disorder without an effective cure. Natural products, while showing promise as potential therapeutics for AD, remain underexplored. AIMS: This study was conducted with the goal of identifying potential anti-AD candidates from natural sources using Caenorhabditis elegans (C. elegans) AD-like models and exploring their mechanisms of action. MATERIALS & METHODS: Our laboratory's in-house herbal extract library was utilized to screen for potential anti-AD candidates using the C. elegans AD-like model CL4176. The neuroprotective effects of the candidates were evaluated in multiple C. elegans AD-like models, specifically targeting Aß- and Tau-induced pathology. In vitro validation was conducted using PC-12 cells. To investigate the role of autophagy in mediating the anti-AD effects of the candidates, RNAi bacteria and autophagy inhibitors were employed. RESULTS: The ethanol extract of air-dried fruits of Luffa cylindrica (LCE), a medicine-food homology species, was found to inhibit Aß- and Tau-induced pathology (paralysis, ROS production, neurotoxicity, and Aß and pTau deposition) in C. elegans AD-like models. LCE was non-toxic and enhanced C. elegans' health. It was shown that LCE activates autophagy and its anti-AD efficacy is weakened with the RNAi knockdown of autophagy-related genes. Additionally, LCE induced mTOR-mediated autophagy, reduced the expression of AD-associated proteins, and decreased cell death in PC-12 cells, which was reversed by autophagy inhibitors (bafilomycin A1 and 3-methyladenine). DISCUSSION: LCE, identified from our natural product library, emerged as a valuable autophagy enhancer that effectively protects against neurodegeneration in multiple AD-like models. RNAi knockdown of autophagy-related genes and cotreatment with autophagy inhibitors weakened its anti-AD efficacy, implying a critical role of autophagy in mediating the neuroprotective effects of LCE. CONCLUSION: Our findings highlight the potential of LCE as a functional food or drug for targeting AD pathology and promoting human health.


Subject(s)
Alzheimer Disease , Caenorhabditis elegans Proteins , Luffa , Neuroprotective Agents , Animals , Humans , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Caenorhabditis elegans/genetics , Caenorhabditis elegans/metabolism , Luffa/metabolism , Amyloid beta-Peptides/metabolism , Neuroprotective Agents/pharmacology , Neuroprotective Agents/therapeutic use , Fruit/metabolism , Autophagy , Disease Models, Animal , Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans Proteins/pharmacology
3.
ACS Omega ; 6(43): 28936-28945, 2021 Nov 02.
Article in English | MEDLINE | ID: mdl-34746585

ABSTRACT

Existing studies of coal self-ignition and impact frictional sparks do not provide valid support for the analysis of ignition sources in all cases of methane explosions in the gob. In this paper, the explosion in the gob of the Renlou coal mine is used to investigate the piezoelectric effect and ignition characteristics of roof collapse in identifying a new ignition source of gas explosion. Experimental and theoretical analyses conclude that the piezoelectric effect is produced by quartz, which is the main constituent of the roof sandstone. During the loading process, the piezoelectric effect and compressive strength are key factors in the gathering of free charges on rock tips. During rupture, the rock tip retains a large number of charges, forming a ″point-surface″ effect, which triggers an electron avalanche accompanied by an orange-yellow spark lasting over 22 ms, far exceeding the ionization energy and ignition induction period of methane-air mixtures. The piezoelectric effect and compressive strength of the rock cause the generation of electrical sparks, which is the ignition source of the explosion in the gob of Renlou mine II7322.

4.
BMC Anesthesiol ; 20(1): 214, 2020 08 26.
Article in English | MEDLINE | ID: mdl-32847522

ABSTRACT

BACKGROUND: Shivering is a common side effect in women having cesarean delivery (CD) under spinal anesthesia, which can be bothersome to the patient, and it can also interfere with perioperative monitoring. In several studies, the intrathecal (IT) addition of a lipophilic opioid to local anesthetics has been shown to decrease the incidence of shivering. OBJECTIVE: We performed this network meta-analysis to evaluate the effects of intrathecal lipophilic opioids in preventing the incidence of shivering in patients undergoing CD. METHODS: This review was planned according to the PRISMA for Network Meta-Analysis (PRISMA-NMA) guidelines. An English literature search of multiple electronic databases was conducted. We included randomized controlled trials (RCTs) that reported on the incidence of shivering, with study groups receiving either IT fentanyl, sufentanil, or meperidine in women undergoing CD under spinal anesthesia. Quality of the studies was assessed using the modified Oxford scoring system. Using random-effects modeling, dichotomous data were extracted and summarized using odds ratio (OR) with a 95% credible interval (CrI). Statistical analysis was conducted using R studio version 1.0.153 - Inc. RESULTS: Twenty-one studies consisting of 1433 patients (Control group: 590 patients in twenty-one studies; Fentanyl group:199 patients in seven studies; Sufentanil group: 156 patients in five studies; Meperidine group: 488 patients in ten studies) met the inclusion criteria for this systematic review investigating the effect of intrathecal lipophilic opioids in preventing the incidence of shivering in women undergoing cesarean delivery under spinal anesthesia. Methodological validity scores ranged from 3 to 7. The Bayesian mixed network estimate showed the incidence of shivering was significantly lower with IT fentanyl (pooled odds ratio (OR): 0.13; 95% credible interval (CrI): 0.04 to 0.35; P = 0.0004) and IT meperidine (OR: 0.12; 95% CrI: 0.05 to 0.29; P < 0.00001), but not with IT sufentanil (OR: 0.37; 95% CrI: 0.11 to 1.22; P = 0.23). The IT fentanyl group had a significantly lower incidence of intraoperative discomfort [Risk Ratio (RR): 0.19; 95% CI: 0.10-0.35; P < 0.00001], the IT sufentanil group had a significantly higher incidence of pruritus (RR: 6.18; 95% CI: 1.18-32.46; P = 0.03) The IT meperidine group had a significantly lower incidence of intraoperative discomfort (2.7% vs. 13.6%; RR: 0.22; 95% CI: 0.09-0.55; P = 0.001), but there was a significant increase in nausea and vomiting (IT meperidine group vs. Control group: 42.7% vs. 19.4%; RR: 2.56; 95% CI: 1.14-5.75; P = 0.02). Meta-regression analysis based on the opioid dose and quality of the study did not impact the final inference of our result. CONCLUSION: IT fentanyl significantly decreased the incidence of shivering in women undergoing CD under spinal anesthesia without increasing maternal adverse events, confirming that routine use in this patient population is a good choice. IT sufentanil did not decrease the incidence of shivering. IT meperidine decreased the incidence and severity of shivering, but its use was also associated with significant nausea and vomiting.


Subject(s)
Analgesics, Opioid/administration & dosage , Anesthesia, Spinal/methods , Cesarean Section/methods , Injections, Spinal/methods , Randomized Controlled Trials as Topic/methods , Shivering/drug effects , Analgesics, Opioid/adverse effects , Anesthesia, Obstetrical/adverse effects , Anesthesia, Obstetrical/methods , Anesthesia, Spinal/adverse effects , Bayes Theorem , Female , Fentanyl/administration & dosage , Fentanyl/adverse effects , Humans , Incidence , Injections, Spinal/adverse effects , Network Meta-Analysis , Postoperative Nausea and Vomiting/chemically induced , Pregnancy , Shivering/physiology , Sufentanil/administration & dosage , Sufentanil/adverse effects
5.
J Biomed Res ; 32(5): 442-453, 2018 Nov 20.
Article in English | MEDLINE | ID: mdl-30333280

ABSTRACT

Non-Hodgkin lymphoma (NHL) is one of the most common cancers affecting men of reproductive age. The high response rate of bendamustine as first-line treatment for NHL, coupled with young age of patients, makes elucidation of the impact of treatment on male reproduction important. Our aim was to determine the effects of bendamustine on male reproduction by animal model. Male mice were treated with bendamustine (40 mg/kg) through tail vein injection while cisplatin was given as a standard (3 mg/kg) through intraperitoneal injection. After 3 weeks, bendamustine induced weight loss and sperm morphology abnormalities were compared to the control. Additionally, sperm with folded tails were the most frequent abnormality in bendamustine-treated mice. But the mechanism of sperm abnormality induced by bendamustine remains to be elucidated. These results indicate bendamustine may affect spermatozoa of patients who have been treated for NHL.

6.
Biol Lett ; 14(8)2018 08.
Article in English | MEDLINE | ID: mdl-30158139

ABSTRACT

Plants are moving poleward and upward in response to climate warming. However, such movements lag behind the expanding warming front for many reasons, including the impediment of plant movement caused by unusual cold events. In this study, we measured the maximum photochemical efficiency of photosystem II (Fv/Fm) in 101 warm-climate angiosperm species to assess their cold tolerance at the end of a severe chilling period of 49 days in a southern subtropical region (Nanning) in China. We found that 36 of the 101 species suffered from chilling-induced physiological injury, with predawn Fv/Fm values of less than 0.7. There was a significant exponential relationship between the predawn Fv/Fm and northern latitudinal limit of a species; species with a lower latitudinal limit suffered more. Our results suggest that the range limits of warm-climate plants are potentially influenced by their physiological sensitivity to chilling temperatures and that their poleward movement might be impeded by extreme cold events. The quick measurement of Fv/Fm is useful for assessing the cold tolerance of plants, providing valuable information for modelling species range shifts under changing climate conditions and species selection for horticultural management and urban landscape design.


Subject(s)
Cold Temperature/adverse effects , Magnoliopsida/physiology , Photosynthesis/physiology , Adaptation, Physiological , China , Climate Change , Plant Dispersal/physiology , Plant Physiological Phenomena
7.
Br J Cancer ; 117(10): 1486-1494, 2017 Nov 07.
Article in English | MEDLINE | ID: mdl-28926525

ABSTRACT

BACKGROUND: Because of medical advances, metastatic breast cancer (MBC) is now viewed as a chronic disease, rather than an imminent death sentence. Helping women live with this disease requires more than a medical approach to symptoms. Thus, a mentor-based and supportive-expressive program 'Be Resilient to Breast Cancer' (BRBC) was designed to help Chinese women with MBC enhance their resilience levels, biopsychosocial functions, and potentially extend their life span. METHODS: A total of 226 women with MBC were randomly assigned, in a 1 : 1 ratio, to an intervention group (IG) that participated in BRBC or to a control group (CG) that received no intervention. Be Resilient to Breast Cancer was conducted for 120 min once a week. Primary outcomes were cancer-specific survival and secondary outcomes were resilience, Allostatic Load Index (ALI), anxiety, depression, and quality of life (QoL). The Cox proportional-hazards model was used for survival analysis and growth mixture models were performed for secondary outcomes. RESULTS: Be Resilient to Breast Cancer did not significantly prolong 3- or 5-year survival (median survival, 36.7 months in IG and 31.5 months in CG). The hazard ratio for death was 0.736 (95% CI, 0.525-1.133, P=0.076; univariate Cox model) and 0.837 (95% CI, 0.578-1.211, P=0.345; multivariate Cox analysis). The IG improved in anxiety (ES=0.85, P<0.001), depression (ES=0.95, P<0.001), QoL (ES=0.55, P<0.001), resilience (ES=0.67, P<0.001), and ALI (ES=0.90, P<0.001) compared to CG. CONCLUSIONS: BRBC does not improve survival of women with MBC in this study, though longer follow up is warranted. It positively impacts resilience, QoL, ALI, and emotional distress.


Subject(s)
Breast Neoplasms/mortality , Breast Neoplasms/psychology , Mentoring/methods , Quality of Life , Resilience, Psychological , Adult , Aged , China , Female , Humans , Kaplan-Meier Estimate , Mentors , Middle Aged , Proportional Hazards Models
8.
Psychooncology ; 26(6): 829-835, 2017 06.
Article in English | MEDLINE | ID: mdl-27479936

ABSTRACT

BACKGROUND: Patients with cancer often experience considerable emotional distress, which decreases their quality of life (QOL). Resilience is defined as the psychological characteristics that promote positive adaptation in the face of stress and adversity; however, the relationships among QOL, resilience, and emotional distress in patients with cancer, especially Chinese patients with cancer, are under-researched in the literature. METHODS: Quality of Life Questionnaire Core 30 items, Zung Self-Rating Anxiety Scale, and the Zung Self-Rating Depression Scale were applied in this study. Univariate correlated analysis and multivariate logistic regression analysis were used to test the associations among resilience, emotional distress, and QOL with a sample of 276 participants. A Sobel test was conducted to determine whether the indirect effect of resilience was significant. RESULTS: The mean ratings of QOL (59.2), resilience (20.8), anxiety (43.1), and depression (47.7) were reported. The correlations between resilience and QOL in patients with lung cancer were significantly increased compared with patients with gastric or colorectal cancer (Spearman coefficient squares of 0.284, 0.189, and 0.227, respectively). The highest quartile of the resilience level was associated with a 64% (odds ratio = 0.36, 95% confidence interval = 0.17-0.75, P = .006), 70% (odds ratio = 0.30, 95% confidence interval = 0.14-0.63), and 90% (odds ratio = 0.10, 95% confidence interval = 0.04-0.26, P < .001) reduction in the risk of emotional distress compared with the lowest quartile. The Sobel test indicated a buffering effect of resilience that was significant for depression (Sobel value = 2.002, P = .045) but not anxiety (Sobel value = 1.336, P = .182). CONCLUSIONS: The present study suggests that psychological resilience is positively associated with QOL and may comprise a robust buffer between depression and QOL in Chinese patients with cancer.


Subject(s)
Colorectal Neoplasms/psychology , Lung Neoplasms/psychology , Quality of Life , Stomach Neoplasms/psychology , Stress, Psychological/psychology , Adult , Aged , Anxiety/psychology , China , Colorectal Neoplasms/diagnosis , Depression/psychology , Female , Humans , Lung Neoplasms/diagnosis , Male , Middle Aged , Resilience, Psychological , Stomach Neoplasms/diagnosis , Surveys and Questionnaires
9.
Breast Cancer Res Treat ; 158(3): 509-22, 2016 08.
Article in English | MEDLINE | ID: mdl-27400910

ABSTRACT

To reduce the risk of adjustment problems for breast cancer patients in mainland China, we examined the efficacy of a multidiscipline mentor-based program, Be Resilient to Breast Cancer (BRBC), delivered after breast surgery to (a) increase protective factors of social support, hope for the future, etc.; (b) decrease risk factors of Physical and Emotional Distress; and (c) increase outcomes of Resilience, Transcendence and Quality of Life (QOL). A multisite randomized controlled trial was conducted at 6 specialist cancer hospitals. 101 and 103 breast cancer patients were allocated to intervention group (IG) and control group (CG), respectively, and 112 general females (without breast cancer) were allocated to the norm group (NG). Participants completed measures that were related to latent variables derived from the Resilience Model for Breast Cancer (RM-BC) at baseline (T1), 2 months (T2), 6 months (T3), and 12 months (T4) after intervention. At T2, the IG reported significantly lower Depression (ES = 0.65,P = 0.0019) and Illness Uncertainty (ES = 0.57, P = 0.004), better Hope (ES = 0.81, P < 0.001) and QOL (ES = 0.60, P = 0.002) than did the CG. At T3, the IG reported significantly lower Anxiety (ES = 0.74, P < 0.001), better Social Support (ES = 0.51,P = 0.009), Transcendence (ES = 0.87, P < 0.001), and Resilience (ES = 0.83, P < 0.001) compared with the CG. At T4, the IG reported better Resilience though not significant (P = 0.085) and better Transcendence (P = 0.0243) than did the NG. The BRBC intervention improves the positive health outcomes and decreases the risk factors of illness-related distress of breast cancer patients during the high-risk cancer treatment.


Subject(s)
Breast Neoplasms/psychology , Mentoring/methods , Survivors/psychology , Breast Neoplasms/surgery , China , Female , Humans , Quality of Life , Resilience, Psychological , Self Efficacy , Social Support , Treatment Outcome
10.
Food Chem ; 170: 110-7, 2015 Mar 01.
Article in English | MEDLINE | ID: mdl-25306324

ABSTRACT

HPLC analysis of samples from four major fermentation procedures of Jing-Wei Fu brick tea showed that the level of major tea catechins epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) dropped increasingly to about 1/3 in the final product. Phytochemical study of the final product led to the discovery of four new B-ring fission metabolites of catechins (BRFCs) Fuzhuanin C-F (1-4) together with three known BRFCs (5-7), six known catechins (8-13), five simple phenols (14-18), seven flavones and flavone glycosides (19-25), two alkaloids (26, 27), three triterpenoids (28-30) and one steroid (31). The structures were elucidated by spectroscopic methods including 1D and 2D NMR, LC-HR-ESI-MS, IR, and CD spectra. Five compounds (16-18, 28, 29) were reported for the first time in tea. Possible pathways for the degradation of major tea catechins and the generation of BRFCs were also provided.


Subject(s)
Chromatography, High Pressure Liquid/methods , Phenols/analysis , Polyphenols/analysis , Tea/chemistry , Fermentation
11.
Molecules ; 18(3): 2840-50, 2013 Mar 01.
Article in English | MEDLINE | ID: mdl-23455673

ABSTRACT

Two new limonoids, toonins A (1) and B (2), and one new dihydrobenzofuran norlignan, toonin C (3), were isolated from the roots of Toona sinensis together with the ten known compounds 4-methoxy-6-(2',4'-dihydroxy-6'-methylphenyl)-pyran-2-one (4), bourjotinolone A (5), proceranone (6), matairesinol (7), 4-hydroxy-3-methoxybenzene-ethanol (8), syringic acid (9), isoscopoletin (10), lyoniresinol (11), aloeemodin (12), and ß-sitosterol (13). Their structures were elucidated on the basis of one- and two-dimensional spectroscopic analysis. Isolation of compounds 4, 6-13 from this plant is reported here for the first time.


Subject(s)
Cedrela/chemistry , Limonins/chemistry , Plant Roots/chemistry , Free Radical Scavengers/chemistry , Free Radical Scavengers/pharmacology , Limonins/pharmacology , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Plant Extracts/chemistry , Plant Extracts/pharmacology , Stereoisomerism
12.
J Med Chem ; 51(23): 7478-85, 2008 Dec 11.
Article in English | MEDLINE | ID: mdl-19006286

ABSTRACT

The discovery of novel uracil phenylethylamines bearing a butyric acid as potent human gonadotropin-releasing hormone receptor (hGnRH-R) antagonists is described. A major focus of this optimization was to improve the CYP3A4 inhibition liability of these uracils while maintaining their GnRH-R potency. R-4-{2-[5-(2-fluoro-3-methoxyphenyl)-3-(2-fluoro-6-[trifluoromethyl]benzyl)-4-methyl-2,6-dioxo-3,6-dihydro-2H-pyrimidin-1-yl]-1-phenylethylamino}butyric acid sodium salt, 10b (elagolix), was identified as a potent and selective hGnRH-R antagonist. Oral administration of 10b suppressed luteinizing hormone in castrated macaques. These efforts led to the identification of 10b as a clinical compound for the treatment of endometriosis.


Subject(s)
Drug Discovery , Hydrocarbons, Fluorinated/pharmacology , Pyrimidines/pharmacology , Receptors, LHRH/antagonists & inhibitors , Animals , Caco-2 Cells , Cytochrome P-450 CYP3A Inhibitors , Drug Evaluation, Preclinical , Humans , Hydrocarbons, Fluorinated/chemistry , Hydrocarbons, Fluorinated/metabolism , Macaca fascicularis , Male , Microsomes, Liver/chemistry , Microsomes, Liver/metabolism , Molecular Structure , Pyrimidines/chemistry , Pyrimidines/metabolism , Stereoisomerism , Structure-Activity Relationship , Time Factors
15.
Bioorg Med Chem Lett ; 18(11): 3344-9, 2008 Jun 01.
Article in English | MEDLINE | ID: mdl-18442905

ABSTRACT

Optimization of a series of uracils bearing a 2-fluoro- or 2-chloro-3-methoxyphenyl group at the 5-position resulted in compounds such as 3d and 3f with subnanomolar binding affinity at the human GnRH receptor. While the 2-fluoro-3-methoxyphenyl compound 3a was characterized as a mixture of interchangeable atropisomers, the diastereoisomers of 2-chloro-3-methoxyphenyl analogs were separated. It was found that the aR-atropisomer was much more potent than the aS-isomer based on the X-ray crystal structure of 3h-II.


Subject(s)
Receptors, LHRH/antagonists & inhibitors , Uracil/analogs & derivatives , Uracil/chemical synthesis , Uracil/pharmacology , Crystallography, X-Ray , Humans , Molecular Conformation , Molecular Structure , Stereoisomerism , Structure-Activity Relationship , Uracil/chemistry
16.
Bioorg Med Chem Lett ; 18(11): 3301-5, 2008 Jun 01.
Article in English | MEDLINE | ID: mdl-18442910

ABSTRACT

Incorporation of a carboxylic acid into a series of uracil derivatives as hGnRH-R antagonists resulted in a significant reduction of CYP3A4 inhibitory activity. Highly potent hGnRH antagonists with low CYP3A4 inhibitory liability, such as 8a and 8d, were identified. Thus, 8a had a K(i) of 2.2 nM at GnRH-R and an IC(50) of 36 microM at CYP3A4.


Subject(s)
Cytochrome P-450 CYP3A Inhibitors , Gonadotropin-Releasing Hormone/antagonists & inhibitors , Receptors, LHRH/antagonists & inhibitors , Uracil/analogs & derivatives , Uracil/chemical synthesis , Animals , Cytochrome P-450 CYP3A , Haplorhini , Humans , Inhibitory Concentration 50 , Molecular Structure , Rats , Structure-Activity Relationship , Uracil/pharmacokinetics
17.
Bioorg Med Chem ; 15(16): 5590-603, 2007 Aug 15.
Article in English | MEDLINE | ID: mdl-17561404

ABSTRACT

The present article describes a selection of a new class of small molecule antagonists for the h-GnRH receptor, their preparation, and evaluation in vitro. Three computational methods were combined into a consensus score, to rank order virtual templates. The top 5% of templates were further evaluated in silico and assessed for novelty and synthetic accessibility. The tetrahydropyrido[4,3-d]pyrimidine-2,4-dione core was selected for synthesis and evaluated in vitro. Using an array approach for analog design and synthesis, we were able to drive the binding below 10nM for the h-GnRH receptor after two rounds of optimization.


Subject(s)
Hydrogen/chemistry , Pyrimidines/chemistry , Pyrimidines/pharmacology , Receptors, LHRH/antagonists & inhibitors , Databases, Factual , Ethylamines/chemistry , Humans , Models, Molecular , Molecular Structure , Pyrimidines/chemical synthesis , Receptors, LHRH/metabolism , Structure-Activity Relationship
18.
Bioorg Med Chem Lett ; 17(14): 3845-50, 2007 Jul 15.
Article in English | MEDLINE | ID: mdl-17521908

ABSTRACT

A novel series of 2-(4,5,6,7-tetrahydro-1H-pyrrolo[3,2-c]pyridin-3-yl)-ethylamine derivatives were designed and synthesized as GnRH receptor antagonists. SAR studies led to a series of highly active molecules against both the rat and human receptors. Furthermore, one potent compound, 17j, demonstrated dose-dependent LH suppression in castrated rats.


Subject(s)
Pyridines/pharmacology , Receptors, LHRH/antagonists & inhibitors , Animals , Cells, Cultured , Humans , Pyridines/chemistry , Rats , Structure-Activity Relationship
19.
Mol Pharmacol ; 72(2): 238-47, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17409285

ABSTRACT

Drugs that exhibit insurmountable antagonism are proposed to provide improved clinical efficacy through extended receptor blockade. Long-term suppression of the gonadotropin-releasing hormone receptor (GnRHR) is an important therapeutic approach for a number of sex hormone-dependent diseases. In this study, we describe the mechanism and structural components required for insurmountable activity of a GnRHR antagonist. TAK-013 behaves as an insurmountable antagonist at the human receptor (hGnRHR) but as a surmountable antagonist at the macaque receptor (mGnRHR). Mutation of the eight residues that differ between hGnRHR and mGnRHR identified Ser-203 and Leu-300 in extracellular loops (ECL) 2 and 3 of hGnRHR as essential for the insurmountability of TAK-013. Substitution of the corresponding residues in mGnRHR with Ser and Leu (mGnRHR-P203S/V300L) converts TAK-013 to an insurmountable antagonist. In addition, mutation of Met-24 to Leu in the amino terminus of hGnRHR also ablates the insurmountable antagonism of TAK-013. The mechanism of insurmountability of TAK-013 was determined to be governed by its rate of dissociation from the receptor. Although the association rates of TAK-013 to hGnRHR, mGnRHR, and mGnRHR-P203S/V300L do not differ, the dissociation rate half-life correlates closely with the degree of insurmountability observed (169, 9, and 55 min, respectively). Taken together, these data suggest a model of the GnRHR in which ECL2, ECL3, and the amino terminus engage with TAK-013 upon its binding to the transmembrane region of the receptor. These additional interactions form a "trap door" above TAK-013, restricting its dissociation and thus resulting in its insurmountability.


Subject(s)
Phenylurea Compounds/metabolism , Pyrimidinones/metabolism , Receptors, LHRH/antagonists & inhibitors , Receptors, LHRH/chemistry , Amino Acid Sequence , Animals , Binding Sites , Cell Line , Humans , Ligands , Macaca , Models, Molecular , Molecular Sequence Data , Phenylurea Compounds/pharmacology , Protein Structure, Tertiary , Pyrimidinones/pharmacology , Structure-Activity Relationship
20.
Endocrinology ; 148(2): 857-67, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17095587

ABSTRACT

Suppression of the hypothalamic-pituitary-gonadal axis by peptides that act at the GnRH receptor has found widespread use in clinical practice for the management of sex-steroid-dependent diseases (such as prostate cancer and endometriosis) and reproductive disorders. Efforts to develop orally available GnRH receptor antagonists have led to the discovery of a novel, potent nonpeptide antagonist, NBI-42902, that suppresses serum LH concentrations in postmenopausal women after oral administration. Here we report the in vitro and in vivo pharmacological characterization of this compound. NBI-42902 is a potent inhibitor of peptide radioligand binding to the human GnRH receptor (K(i) = 0.56 nm). Tritiated NBI-42902 binds with high affinity (K(d) = 0.19 nm) to a single class of binding sites and can be displaced by a range of peptide and nonpeptide GnRH receptor ligands. In vitro experiments demonstrate that NBI-42902 is a potent functional, competitive antagonist of GnRH stimulated IP accumulation, Ca(2+) flux, and ERK1/2 activation. It did not stimulate histamine release from rat peritoneal mast cells. Finally, it is effective in lowering serum LH in castrated male macaques after oral administration. Overall, these data provide a benchmark of pharmacological characteristics required for a nonpeptide GnRH antagonist to effectively suppress gonadotropins in humans and suggest that NBI-42902 may have clinical utility as an oral agent for suppression of the hypothalamic-pituitary-gonadal axis.


Subject(s)
Receptors, LHRH/antagonists & inhibitors , Thymine/analogs & derivatives , Administration, Oral , Animals , Binding Sites , Binding, Competitive , Calcium Channel Blockers/pharmacology , Cell Line , Enzyme Activation/drug effects , Gonadotropin-Releasing Hormone/pharmacology , Histamine Release/drug effects , Humans , Inositol Phosphates/antagonists & inhibitors , Inositol Phosphates/metabolism , Ligands , Luteinizing Hormone/blood , Macaca , Male , Mast Cells/metabolism , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , Orchiectomy , Receptors, LHRH/metabolism , Thymine/administration & dosage , Thymine/metabolism , Thymine/pharmacology
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