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Brazilian Oral Research 2023The current study aims to assess the effectiveness of e-learning in compliance with the new biosafety recommendations in dentistry in the context of COVID-19 applied to...
The current study aims to assess the effectiveness of e-learning in compliance with the new biosafety recommendations in dentistry in the context of COVID-19 applied to the clinical staff of a dental school in Brazil. A quasi-experimental epidemiological study was carried out by means of a structured, pre-tested online questionnaire, applied before and after an educational intervention, using an e-learning format. After data collection, statistical tests were performed. A total of 549 members of the clinical staff participated in the study in the two collection phases, with a return rate of 26.9%. After the e-learning stage, a reduction was found in the reported use of disposable gloves, protective goggles, and surgical masks. The course had no impact on the staff's knowledge concerning the proper sequence for donning PPE and showed 100% effectiveness regarding proper PPE doffing sequence. Knowledge about avoiding procedures that generate aerosols in the clinical setting was improved. Despite the low rate of return, it can be concluded that online intervention alone was ineffective in significantly improving learning about the new clinical biosafety guidelines. Therefore, the use of hybrid teaching and repetitive training is highly recommended.
Topics: Humans; Computer-Assisted Instruction; COVID-19; Brazil; Diazooxonorleucine; Dentistry
PubMed: 37341233
DOI: 10.1590/1807-3107bor-2023.vol37.0060 -
Acta Biochimica Et Biophysica Sinica Mar 2023Ferroptosis is a type of programmed cell death closely related to amino acid metabolism. Pancreatic cancer cells have a strong dependence on glutamine, which serves as a...
Ferroptosis is a type of programmed cell death closely related to amino acid metabolism. Pancreatic cancer cells have a strong dependence on glutamine, which serves as a carbon and nitrogen substrate to sustain rapid growth. Glutamine also aids in self-protection mechanisms. However, the effect of glutamine on ferroptosis in pancreatic cancer remains largely unknown. Here, we aim to explore the association between ferroptosis and glutamine deprivation in pancreatic cancer. The growth of pancreatic cancer cells in culture media with or without glutamine is evaluated using Cell Counting Kit-8. Reactive oxygen species (ROS) are measured by 2',7'-dichlorodihydrofluorescein diacetate staining. Ferroptosis is assessed by BODIPY-C11 dye using confocal microscopy and flow cytometry. Amino acid concentrations are measured using ultrahigh-performance liquid chromatography-tandem mass spectrometry. Isotope-labelled metabolic flux analysis is performed to track the metabolic flow of glutamine. Additionally, RNA sequencing is performed to analyse the genetic alterations. Glutamine deprivation inhibits pancreatic cancer growth and induces ferroptosis both and . Additionally, glutamine decreases ROS formation via glutathione production in pancreatic cancer cells. Interestingly, glutamine inhibitors (diazooxonorleucine and azaserine) promotes ROS formation and ferroptosis in pancreatic cancer cells. Furthermore, ferrostatin, a ferroptosis inhibitor, rescues ferroptosis in pancreatic cancer cells. Glutamine deprivation leads to changes in molecular pathways, including cytokine-cytokine receptor interaction pathways ( , , , , , and ). Thus, exogenous glutamine is required for the detoxification of ROS in pancreatic cancer cells, thereby preventing ferroptosis.
Topics: Humans; Ferroptosis; Glutamine; Reactive Oxygen Species; Apoptosis; Pancreatic Neoplasms
PubMed: 36942991
DOI: 10.3724/abbs.2023029 -
Discover Oncology Feb 2023Carbohydrate antigen 19-9 (CA19-9) is the most widely used biomarker for pancreatic cancer. Since CA19-9 closely correlates with patient outcome and tumor stage in...
BACKGROUND
Carbohydrate antigen 19-9 (CA19-9) is the most widely used biomarker for pancreatic cancer. Since CA19-9 closely correlates with patient outcome and tumor stage in pancreatic cancer, the deciphering of CA19-9 biosynthesis provides a potential clue for treatment.
METHODS
Concentration of amino acids was detected by ultrahigh-performance liquid chromatography tandem mass spectrometry. Metabolic flux of glutamine was examined by isotope tracing untargeted metabolomics. Label-free quantitative N-glycosylation proteomics was used to examine N-glycosylation alterations.
RESULTS
Among all amino acids, glutamine was higher in CA19-9-high pancreatic cancers (> 37 U/mL, 66 cases) than in CA19-9-normal clinical specimens (≤ 37 U/mL, 37 cases). The glutamine concentration in clinical specimens was positively correlated with liver metastasis or lymphovascular invasion. Glutamine blockade using diazooxonorleucine suppressed pancreatic cancer growth and intraperitoneal and lymphatic metastasis. Glutamine promotes O-GlcNAcylation, protein glycosylation, and CA19-9 biosynthesis through the hexosamine biosynthetic pathway. UDP-N-acetylglucosamine (UDP-GlcNAc) levels correlated with the glutamine influx through hexosamine biosynthetic pathway and supported CA19-9 biosynthesis.
CONCLUSIONS
Glutamine is a substrate for CA19-9 biosynthesis in pancreatic cancer. Glutamine blockade may be a potential therapeutic strategy for pancreatic cancer.
PubMed: 36797531
DOI: 10.1007/s12672-023-00628-z -
Science Advances Nov 20226-Diazo-5-oxo-l-norleucine (DON) is a glutamine antagonist that suppresses cancer cell metabolism but concurrently enhances the metabolic fitness of tumor CD8 T cells....
6-Diazo-5-oxo-l-norleucine (DON) is a glutamine antagonist that suppresses cancer cell metabolism but concurrently enhances the metabolic fitness of tumor CD8 T cells. DON showed promising efficacy in clinical trials; however, its development was halted by dose-limiting gastrointestinal (GI) toxicities. Given its clinical potential, we designed DON peptide prodrugs and found DRP-104 [isopropyl()-2-(()-2-acetamido-3-(1-indol-3-yl)-propanamido)-6-diazo-5-oxo-hexanoate] that was preferentially bioactivated to DON in tumor while bioinactivated to an inert metabolite in GI tissues. In drug distribution studies, DRP-104 delivered a prodigious 11-fold greater exposure of DON to tumor versus GI tissues. DRP-104 affected multiple metabolic pathways in tumor, including decreased glutamine flux into the TCA cycle. In efficacy studies, both DRP-104 and DON caused complete tumor regression; however, DRP-104 had a markedly improved tolerability profile. DRP-104's effect was CD8 T cell dependent and resulted in robust immunologic memory. DRP-104 represents a first-in-class prodrug with differential metabolism in target versus toxicity tissue. DRP-104 is now in clinical trials under the FDA Fast Track designation.
Topics: Humans; Prodrugs; Diazooxonorleucine; Glutamine; CD8-Positive T-Lymphocytes; Neoplasms; Enzyme Inhibitors
PubMed: 36383674
DOI: 10.1126/sciadv.abq5925 -
British Journal of Anaesthesia Nov 2022Hypersensitivity to general anaesthetics predicts adverse postoperative outcomes in patients. Hypoxia exerts extensive pathophysiological effects on the brain; however,...
BACKGROUND
Hypersensitivity to general anaesthetics predicts adverse postoperative outcomes in patients. Hypoxia exerts extensive pathophysiological effects on the brain; however, whether hypoxia influences sevoflurane sensitivity and its underlying mechanisms remain poorly understood.
METHODS
Mice were acclimated to hypoxia (oxygen 10% for 8 h day) for 28 days and anaesthetised with sevoflurane; the effective concentrations for 50% of the animals (EC) showing loss of righting reflex (LORR) and loss of tail-pinch withdrawal response (LTWR) were determined. Positron emission tomography-computed tomography, O-glycoproteomics, seahorse analysis, carbon-13 tracing, site-specific mutagenesis, and electrophysiological techniques were performed to explore the underlying mechanisms.
RESULTS
Compared with the control group, the hypoxia-acclimated mice required higher concentrations of sevoflurane to present LORR and LTWR (EC50: 1.61 [0.03]% vs 1.46 [0.04]%, P<0.01; EC50: 2.46 [0.14]% vs 2.22 [0.06]%, P<0.01). Hypoxia-induced reduction in sevoflurane sensitivity was correlated with elevation of protein O-linked N-acetylglucosamine (O-GlcNAc) modification in brain, especially in the thalamus, and could be abolished by 6-diazo-5-oxo-l-norleucine, a glutamine fructose-6-phosphate amidotransferase inhibitor, and mimicked by thiamet-G, a selective O-GlcNAcase inhibitor. Mechanistically, O-GlcNAcylation drives de novo synthesis of glutamine from glucose in astrocytes and promotes the glutamate-glutamine cycle, partially via glycolytic flux and activation of glutamine synthetase.
CONCLUSIONS
Intermittent hypoxia exposure decreased mouse sensitivity to sevoflurane anaesthesia through enhanced O-GlcNAc-dependent modulation of the glutamate-glutamine cycle in the brain.
Topics: Animals; Mice; Acetylglucosamine; Sevoflurane; Glutamine; Diazooxonorleucine; Glutamate-Ammonia Ligase; Brain; Hypoxia; Glucose; Anesthetics, General; Oxygen; Glutamates
PubMed: 36031420
DOI: 10.1016/j.bja.2022.06.041 -
Molecules (Basel, Switzerland) Aug 2022Cancer cells change their glucose and glutamine (GLU) metabolism to obtain the energy required to continue growing. Glutaminase (GLS) plays a crucial role in promoting...
Cancer cells change their glucose and glutamine (GLU) metabolism to obtain the energy required to continue growing. Glutaminase (GLS) plays a crucial role in promoting cell metabolism for cancer cell growth; targeting GLU metabolism by inhibiting GLS has attracted interest as a potential cancer management strategy. Herein, we employed a sequential screening of traditional Chinese medicine (TCM) database followed by drug-likeness and molecular dynamics simulations against the active site of GLS. We report 12 potent compounds after screening the TCM database against GLS, followed by a drug-likeness filter with Lipinski and Veber rule criteria. Among them, ZINC03978829 and ZINC32296657 were found to have higher binding energy (BE) values than the control compound 6-Diazo-5-Oxo-L-Norleucine, with BEs of -9.3 and -9.7 kcal/mol, respectively, compared to the BE of 6-Diazo-5-Oxo-L-Norleucine (-4.7 kcal/mol) with GLS. Molecular dynamics simulations were used to evaluate the results further, and a 100 ns MD simulation revealed that the hits form stable complexes with GLS and formed 2-5 hydrogen bond interactions. This study indicates that these hits might be employed as GLS inhibitors in the battle against cancer. However, more laboratory tests are a prerequisite to optimize them as GLS inhibitors.
Topics: Diazooxonorleucine; Early Detection of Cancer; Glutaminase; Humans; Molecular Docking Simulation; Molecular Dynamics Simulation; Neoplasms; Neoplastic Processes
PubMed: 35956989
DOI: 10.3390/molecules27155042 -
Molecular Cancer Therapeutics Oct 2022Glutamine is a conditionally essential amino acid consumed by rapidly proliferating cancer cells, which deprives the same fuel from immune cells and contributes to tumor...
Glutamine is a conditionally essential amino acid consumed by rapidly proliferating cancer cells, which deprives the same fuel from immune cells and contributes to tumor immune evasion. As such, the broad antagonism of glutamine in tumors and the tumor microenvironment may lead to direct antitumor activity and stimulation of antitumoral immune responses. DRP-104 (sirpiglenastat) was designed as a novel prodrug of the broad-acting glutamine antagonist 6-diazo-5-oxo-L-norleucine (DON). DRP-104 is an inactive form that is preferentially converted to DON within tumors. Metabolomic profiling of tumors treated with DRP-104 revealed widespread changes indicative of the disruption of tumor anabolism and canonical cancer metabolism pathways; including altered glutamine metabolism while several immunosuppressive metabolites were decreased. Gene expression profiling revealed broad immunological modulation, confirmed by flow cytometry indicating that DRP-104 treatment resulted in substantial and broad changes in various immune cell infiltrates, such as increased TIL, T, NK, and NK T cells. Functionally, T cells became more proliferative and less exhausted; tumor-associated macrophages were polarized to the M1 phenotype; MDSCs and protumorigenic proteins were decreased in TME. Finally, DRP-104 demonstrated significant antitumor activity as a monotherapy, which was further enhanced in combination with checkpoint blockade therapies, leading to improved survival and long-term durable cures. In summary, DRP-104 broadly remodels the tumor microenvironment by inducing extensive tumor metabolism effects and enhancing the infiltration and function of multiple immune cells distinct from those obtained by checkpoint inhibitor therapy. This unique mechanism of action supports the ongoing clinical development of DRP-104 alone and in combination with checkpoint inhibitors.
Topics: Amino Acids, Essential; Cell Line, Tumor; Diazooxonorleucine; Glutamine; Humans; Immune System; Neoplasms; Prodrugs; Tumor Microenvironment
PubMed: 35930753
DOI: 10.1158/1535-7163.MCT-22-0282 -
Pharmacologically Inferred Glycolysis and Glutaminolysis Requirement of B Cells in Lupus-Prone Mice.Journal of Immunology (Baltimore, Md. :... May 2022Several studies have shown an enhanced metabolism in the CD4 T cells of lupus patients and lupus-prone mice. Little is known about the metabolism of B cells in lupus. In...
Several studies have shown an enhanced metabolism in the CD4 T cells of lupus patients and lupus-prone mice. Little is known about the metabolism of B cells in lupus. In this study, we compared the metabolism of B cells between lupus-prone B6. triple-congenic mice and C57BL/6 controls at steady state relative to autoantibody production, as well as during T cell-dependent (TD) and T cell-independent (TI) immunizations. Starting before the onset of autoimmunity, B cells from triple-congenic mice showed an elevated glycolysis and mitochondrial respiration, which were normalized in vivo by inhibiting glycolysis with a 2-deoxy-d-glucose (2DG) treatment. 2DG greatly reduced the production of TI-Ag-specific Abs, but showed minimal effect with TD-Ags. In contrast, the inhibition of glutaminolysis with 6-diazo-5-oxo-l-norleucine had a greater effect on TD than TI-Ag-specific Abs in both strains. Analysis of the TI and TD responses in purified B cells in vitro suggests, however, that the glutaminolysis requirement is not B cell-intrinsic. Thus, B cells have a greater requirement for glycolysis in TI than TD responses, as inferred from pharmacological interventions. B cells from lupus-prone and control mice have different intrinsic metabolic requirements or different responses toward 2DG and 6-diazo-5-oxo-l-norleucine, which mirrors our previous results obtained with follicular Th cells. Overall, these results predict that targeting glucose metabolism may provide an effective therapeutic approach for systemic autoimmunity by eliminating both autoreactive follicular Th and B cells, although it may also impair TI responses.
Topics: Animals; B-Lymphocytes; Diazooxonorleucine; Glycolysis; Humans; Mice; Mice, Congenic; Mice, Inbred C57BL; T-Lymphocytes, Helper-Inducer
PubMed: 35387839
DOI: 10.4049/jimmunol.2100356 -
Chembiochem : a European Journal of... Apr 2022During the biosynthesis of alazopeptin, a tripeptide composed of two molecules of 6-diazo-5-oxo-L-norleucine (DON) and one of alanine, the α/β hydrolase AzpM...
During the biosynthesis of alazopeptin, a tripeptide composed of two molecules of 6-diazo-5-oxo-L-norleucine (DON) and one of alanine, the α/β hydrolase AzpM synthesizes the DON-DON dipeptide using DON tethered to the carrier protein AzpF (DON-AzpF). However, whether AzpM catalyzes the condensation of DON-AzpF with DON or DON-AzpF remains unclear. Here, to distinguish between these two condensation possibilities, the reaction catalyzed by AzpM was examined in vitro using a DON analogue, azaserine (AZS). We found that AzpM catalyzed the condensation between AZS-AzpF and DON-AzpF, but not between AZS-AzpF and DON. Possible reaction intermediates, DON-DON-AzpF and AZS-AZS-AzpF, were also detected during AzpM-catalyzed dipeptide formation from DON-AzpF and AZS-AzpF, respectively. From these results, we concluded that AzpM catalyzed the condensation of the two molecules of DON-AzpF and subsequent hydrolysis to produce DON-DON. Thus, AzpM is an unprecedented α/β hydrolase that catalyzes dipeptide synthesis from two molecules of a carrier protein-tethered amino acid.
Topics: Carrier Proteins; Diazooxonorleucine; Dipeptides; Hydrolases
PubMed: 35132756
DOI: 10.1002/cbic.202100700 -
Cellular Immunology Dec 2021Infection of the cornea with HSV results in an immune-inflammatory reaction orchestrated by proinflammatory T cells that is a major cause of human vision impairment. The...
Infection of the cornea with HSV results in an immune-inflammatory reaction orchestrated by proinflammatory T cells that is a major cause of human vision impairment. The severity of lesions can be reduced if the representation of inflammatory T cells is changed to increase the presence of T cells with regulatory function. This report shows that inhibiting glutamine metabolism using 6-Diazo-5-oxo-l-norleucine (DON) administered via intraperitoneal (IP) starting 6 days after ocular infection and continued until day 15 significantly reduced the severity of herpetic stromal keratitis lesions. The therapy resulted in reduced neutrophils, macrophages as well proinflammatory CD4 Th1 and Th17 T cells in the cornea, but had no effect on levels of regulatory T cells. A similar change in the representation of inflammatory and regulatory T cells occurred in the trigeminal ganglion (TG) the site where HSV infection establishes latency. Glutamine metabolism was shown to be required for the in-vitro optimal induction of both Th1 and Th17 T cells but not for the induction of Treg that were increased when glutamine metabolism was inhibited. Inhibiting glutamine metabolism also changed the ability of latently infected TG cells from animals previously infected with HSV to reactivate and produce infectious virus.
Topics: Animals; Diazooxonorleucine; Glutamine; Keratitis, Herpetic; Latent Infection; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; T-Lymphocytes; Trigeminal Ganglion; Virus Activation; Virus Latency
PubMed: 34678554
DOI: 10.1016/j.cellimm.2021.104450