-
Journal of Medicinal Chemistry Nov 2023The glutamine antagonist 6-diazo-5-oxo-l-norleucine (DON) exhibits remarkable anticancer efficacy; however, its therapeutic potential is hindered by its toxicity to...
The glutamine antagonist 6-diazo-5-oxo-l-norleucine (DON) exhibits remarkable anticancer efficacy; however, its therapeutic potential is hindered by its toxicity to gastrointestinal (GI) tissues. We recently reported the discovery of DRP-104, a tumor-targeted DON prodrug with excellent efficacy and tolerability, which is currently in clinical trials. However, DRP-104 exhibits limited aqueous solubility, and the instability of its isopropyl ester promoiety leads to the formation of an inactive M1-metabolite, reducing overall systemic prodrug exposure. Herein, we aimed to synthesize DON prodrugs with various ester and amide promoieties with improved solubility, GI stability, and DON tumor delivery. Twenty-one prodrugs were synthesized and characterized in stability and pharmacokinetics studies. Of these, , -butyl-()-6-diazo-2-(()-2-(2-(dimethylamino)acetamido)-3-phenylpropanamido)-5-oxo-hexanoate, showed excellent metabolic stability in plasma and intestinal homogenate, high aqueous solubility, and high tumor DON exposures and preserved the ideal tumor-targeting profile of DRP-104. In conclusion, we report a new generation of glutamine antagonist prodrugs with improved physicochemical and pharmacokinetic attributes.
Topics: Humans; Prodrugs; Diazooxonorleucine; Glutamine; Esters; Neoplasms
PubMed: 37949450
DOI: 10.1021/acs.jmedchem.3c01681 -
Journal of Safety Research Sep 2023Worn shoes are an important contributor to occupational slip and fall injuries. Tools to assess worn tread are emerging; imaging tools offer the potential to assist. The...
PROBLEM
Worn shoes are an important contributor to occupational slip and fall injuries. Tools to assess worn tread are emerging; imaging tools offer the potential to assist. The aim of this study was to develop a shoe tread scanner and evaluate its effectiveness to predict slip risk.
METHODS
This study analyzed data from two previous studies in which worn or new slip-resistant shoes were donned during an unexpected slip condition. The shoe tread for each shoe was scanned using a portable scanner that utilized frustrated total internal reflection (FTIR) technology. The shoe tread parameters of the worn region size (WRS) for worn shoes and total contact area for new shoes were measured. These parameters were then used to predict slip risk from the unexpected slip conditions.
RESULTS
The WRS was able to accurately predict slip risk, but the contact area was not.
DISCUSSION
These findings support that increased WRS on the shoe outsole is associated with worse slip outcomes. Furthermore, the tool was able to offer robust feedback across a wide range of tread designs, but the results of this study show that the tool may be more applicable for slip-resistant shoes that are worn compared to their new counterparts.
SUMMARY
This study shows that FTIR technology utilized in this tool may be a useful and portable method for determining slip risk for worn shoes.
PRACTICAL APPLICATIONS
This tool has the potential to be an efficient, objective, end-user tool that improves timely replacement of shoes and prevention of injuries.
Topics: Humans; Shoes; Diazooxonorleucine; Technology
PubMed: 37718069
DOI: 10.1016/j.jsr.2023.05.014 -
Journal of Virology Oct 2016Inflammation is a necessary part of the response to infection but can also cause neuronal injury in both infectious and autoimmune diseases of the central nervous system...
UNLABELLED
Inflammation is a necessary part of the response to infection but can also cause neuronal injury in both infectious and autoimmune diseases of the central nervous system (CNS). A neurovirulent strain of Sindbis virus (NSV) causes fatal paralysis in adult C57BL/6 mice during clearance of infectious virus from the CNS, and the virus-specific immune response is implicated as a mediator of neuronal damage. Previous studies have shown that survival is improved in T-cell-deficient mice and in mice with pharmacological inhibition of the inflammatory response and glutamate excitotoxicity. Because glutamine metabolism is important in the CNS for the generation of glutamate and in the immune system for lymphocyte proliferation, we tested the effect of the glutamine antagonist DON (6-diazo-5-oxo-l-norleucine) on the outcome of NSV infection in mice. DON treatment for 7 days from the time of infection delayed the onset of paralysis and death. Protection was associated with reduced lymphocyte proliferation in the draining cervical lymph nodes, decreased leukocyte infiltration into the CNS, lower levels of inflammatory cytokines, and delayed viral clearance. In vitro studies showed that DON inhibited stimulus-induced proliferation of lymphocytes. When in vivo treatment with DON was stopped, paralytic disease developed along with the inflammatory response and viral clearance. These studies show that fatal NSV-induced encephalomyelitis is immune mediated and that antagonists of glutamine metabolism can modulate the immune response and protect against virus-induced neuroinflammatory disease.
IMPORTANCE
Encephalomyelitis due to infection with mosquito-borne alphaviruses is an important cause of death and of long-term neurological disability in those who survive infection. This study demonstrates the role of the virus-induced immune response in the generation of neurological disease. DON, a glutamine antagonist, inhibited the proliferation of lymphocytes in response to infection, prevented the development of brain inflammation, and protected mice from paralysis and death during treatment. However, because DON inhibited the immune response to infection, clearance of the virus from the brain was also prevented. When treatment was stopped, the immune response was generated, brain inflammation occurred, virus was cleared, and mice developed paralysis and died. Therefore, more definitive treatment for alphaviral encephalomyelitis should inhibit virus replication as well as neuroinflammatory damage.
Topics: Alphavirus; Alphavirus Infections; Animals; Cells, Cultured; Central Nervous System; Cytokines; Diazooxonorleucine; Encephalitis; Encephalitis, Viral; Encephalomyelitis; Female; Glutamine; Lymphocytes; Mice; Mice, Inbred C57BL; Paralysis; Sindbis Virus; Virus Replication
PubMed: 27489275
DOI: 10.1128/JVI.01045-16 -
Journal of Neuro-oncology Feb 2020Glioblastoma is an aggressive central nervous system tumor with a 5-year survival rate of < 10%. The standard therapy for glioblastoma is maximal safe resection,...
PURPOSE
Glioblastoma is an aggressive central nervous system tumor with a 5-year survival rate of < 10%. The standard therapy for glioblastoma is maximal safe resection, followed by radiation therapy and chemotherapy with temozolomide. New approaches to treatment of glioblastoma, such as targeting metabolism, have been studied. The object of this study is to evaluate whether asparagine could be a new target for treatment of glioblastoma.
METHODS
We investigated a potential treatment for glioblastoma that targets the amino acid metabolism. U251, U87, and SF767 glioblastoma cells were treated with L-asparaginase and/or 6-diazo-5-oxo-L-norleucine (DON). L-asparaginase hydrolyzes asparagine into aspartate and depletes asparagine. L-asparaginase has been used for the treatment of acute lymphoblastic leukemia. DON is a glutamine analog that inhibits several glutamine-utilizing enzymes, including asparagine synthetase.
RESULTS
Cell viability was measured after 72 h of treatment. MTS assay showed that L-asparaginase suppressed the proliferation of U251, U87, and SF767 cells in a dose-dependent manner. DON also inhibited the proliferation of these cell lines in a dose-dependent manner. Combined treatment with these drugs had a synergistic antiproliferative effect in these cell lines. Exogenous asparagine rescued the effect of inhibition of proliferation by L-asparaginase and DON. The expression of asparagine synthetase mRNA was increased in cells treated with a combination of L-asparaginase and DON. This combined treatment also induced greater apoptosis and autophagy than did single-drug treatment.
CONCLUSION
The results suggest that the combination of L-asparaginase and DON could be a new therapeutic option for patients with glioblastoma.
Topics: Antineoplastic Agents; Asparaginase; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Cell Survival; Diazooxonorleucine; Glioblastoma; Humans
PubMed: 32020477
DOI: 10.1007/s11060-019-03351-4 -
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 -
Scientific Reports Apr 2019Glutamine metabolism and the mechanistic target of rapamycin (mTOR) pathway are activated cooperatively in the differentiation and activation of inflammatory immune...
Glutamine metabolism and the mechanistic target of rapamycin (mTOR) pathway are activated cooperatively in the differentiation and activation of inflammatory immune cells. But the combined inhibition of both pathways was rarely investigated. This study investigated how inhibiting both glutamine metabolism with 6-diazo-5-oxo-L-norleucine (DON) and mTOR with rapamycin affects immune cells and the arthritis in a mouse model. We revealed that rapamycin and DON additively suppressed CD4 T cell proliferation, and both of them inhibited Th17 cell differentiation. While DON inhibited the differentiation of dendritic cells and macrophages and facilitated that of Ly6G granulocytic (G)-MDSCs more strongly than did rapamycin, G-MDSCs treated with rapamycin but not DON suppressed CD4 T cell proliferation in vitro. The combination of rapamycin and DON significantly suppressed the arthritis in SKG mice more strongly than did each monotherapy in vivo. The numbers of CD4 T and Th17 cells in the spleen were lowest in mice treated with the combination therapy. Thus, combined treatment with rapamycin and DON additively ameliorated the arthritis in SKG mice, possibly by suppressing CD4 T cell proliferation and Th17 differentiation. These results suggest the combination of rapamycin and DON may be a potential novel therapy for arthritis.
Topics: Animals; Arthritis; Bone Marrow Cells; Cell Differentiation; Cell Proliferation; Dendritic Cells; Diazooxonorleucine; Female; Glutamine; Immunosuppression Therapy; Macrophages; Mice, Inbred BALB C; Myeloid-Derived Suppressor Cells; Sirolimus; TOR Serine-Threonine Kinases; Th17 Cells
PubMed: 31011190
DOI: 10.1038/s41598-019-42932-1 -
Biochemical Pharmacology Oct 2018Glutaminase-1 (GLS1) is a mitochondrial enzyme found in endothelial cells (ECs) that metabolizes glutamine to glutamate and ammonia. Although glutaminolysis modulates...
Glutaminase-1 (GLS1) is a mitochondrial enzyme found in endothelial cells (ECs) that metabolizes glutamine to glutamate and ammonia. Although glutaminolysis modulates the function of human umbilical vein ECs, it is not known whether these findings extend to human ECs beyond the fetal circulation. Furthermore, the molecular mechanism by which GLS1 regulates EC function is not defined. In this study, we show that the absence of glutamine in the culture media or the inhibition of GLS1 activity or expression blocked the proliferation and migration of ECs derived from the human umbilical vein, the human aorta, and the human microvasculature. GLS1 inhibition arrested ECs in the G/G phase of the cell cycle and this was associated with a significant decline in cyclin A expression. Restoration of cyclin A expression via adenoviral-mediated gene transfer improved the proliferative, but not the migratory, response of GLS1-inhibited ECs. Glutamine deprivation or GLS1 inhibition also stimulated the production of reactive oxygen species and this was associated with a marked decline in heme oxygenase-1 (HO-1) expression. GLS1 inhibition also sensitized ECs to the cytotoxic effect of hydrogen peroxide and this was prevented by the overexpression of HO-1. In conclusion, the metabolism of glutamine by GLS1 promotes human EC proliferation, migration, and survival irrespective of the vascular source. While cyclin A contributes to the proliferative action of GLS1, HO-1 mediates its pro-survival effect. These results identify GLS1 as a promising therapeutic target in treating diseases associated with aberrant EC proliferation, migration, and viability.
Topics: Aorta; Benzeneacetamides; Cell Movement; Cell Proliferation; Cell Survival; Cyclin A; Diazooxonorleucine; Endothelial Cells; Gene Expression Regulation, Enzymologic; Glutaminase; Glutamine; Heme Oxygenase-1; Humans; RNA Interference; Thiadiazoles; Veins
PubMed: 30144404
DOI: 10.1016/j.bcp.2018.08.032 -
Biochemical and Biophysical Research... Jun 2021Myocardial ischemia/reperfusion (I/R) injury is a major determinant of morbidity and mortality in patients undergoing treatment for cardiac disease. A variety of...
Myocardial ischemia/reperfusion (I/R) injury is a major determinant of morbidity and mortality in patients undergoing treatment for cardiac disease. A variety of treatments are reported to have benefits against reperfusion injury, yet their cardioprotective effects seem to be diminished in obesity, and the underlying mechanism remains elusive. In this study, we found that db/db mice exhibit cardiac hyper-O-GlcNAcylation. In parallel, palmitate treatment (200 mM; 12 h) in H9c2 cells showed an increase in global protein O-GlcNAcylation, along with an impaired insulin response against reperfusion injury. To investigate whether O-GlcNAcylation underlies this phenomenon, glucosamine was used to increase global protein O-GlcNAc levels. Interestingly, histological staining, electrophysiological studies, serum cardiac markers and oxidative stress biomarker assays showed that preischemic treatment with glucosamine attenuated insulin cardioprotection against myocardial infarction, arrhythmia and oxidative stress. Mechanistically, glucosamine treatment decreased insulin-stimulated Akt phosphorylation, a key modulator of cell survival. Furthermore, inhibition of O-GlcNAcylation via 6-diazo-5-oxo-l-norleucine (DON) apparently increased insulin-induced Akt phosphorylation and restored its cardioprotective response against reperfusion injury in palmitate-induced insulin-resistant H9c2 cells. Our findings demonstrated that obesity-induced hyper-O-GlcNAcylation might contribute to the attenuation of insulin cardioprotection against I/R injury.
Topics: Acetylglucosamine; Animals; Arrhythmias, Cardiac; Cardiotonic Agents; Cell Hypoxia; Cell Line; Diazooxonorleucine; Disease Models, Animal; Glycosylation; Humans; Insulin; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Myocardial Reperfusion Injury; Myocardium; Obesity; Protein Processing, Post-Translational; Rats
PubMed: 33915326
DOI: 10.1016/j.bbrc.2021.04.066 -
ELife Jun 2018Energy metabolism is essential for T cell function. However, how persistent antigenic stimulation affects T cell metabolism is unknown. Here, we report that long-term in...
Energy metabolism is essential for T cell function. However, how persistent antigenic stimulation affects T cell metabolism is unknown. Here, we report that long-term in vivo antigenic exposure induced a specific deficit in numerous metabolic enzymes. Accordingly, T cells exhibited low basal glycolytic flux and limited respiratory capacity. Strikingly, blockade of inhibitory receptor PD-1 stimulated the production of IFNγ in chronic T cells, but failed to shift their metabolism towards aerobic glycolysis, as observed in effector T cells. Instead, chronic T cells appeared to rely on oxidative phosphorylation (OXPHOS) and fatty acid oxidation (FAO) to produce ATP for IFNγ synthesis. Check-point blockade, however, increased mitochondrial production of superoxide and reduced viability and effector function. Thus, in the absence of a glycolytic switch, PD-1-mediated inhibition appears essential for limiting oxidative metabolism linked to effector function in chronic T cells, thereby promoting survival and functional fitness.
Topics: Adenosine Triphosphate; Animals; Antibodies, Monoclonal; Antimetabolites, Antineoplastic; B7-H1 Antigen; Cell Lineage; DNA-Binding Proteins; Diazooxonorleucine; Epoxy Compounds; Gene Expression Profiling; Gene Expression Regulation; Glycolysis; Interferon-gamma; Interleukin Receptor Common gamma Subunit; Lymphocyte Activation; Male; Mice; Mice, Inbred BALB C; Mice, Knockout; Oligomycins; Oxidative Phosphorylation; Programmed Cell Death 1 Receptor; Receptors, Antigen, T-Cell; Signal Transduction; T-Lymphocytes; Transplantation, Homologous
PubMed: 29911570
DOI: 10.7554/eLife.30938 -
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