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Journal of Controlled Release :... Apr 2024Modulating the metabolism of cancer cells, immune cells, or both is a promising strategy to potentiate cancer immunotherapy in the nutrient-competitive tumor...
Modulating the metabolism of cancer cells, immune cells, or both is a promising strategy to potentiate cancer immunotherapy in the nutrient-competitive tumor microenvironment. Glutamine has emerged as an ideal target as cancer cells highly rely on glutamine for replenishing the tricarboxylic acid cycle in the process of aerobic glycolysis. However, non-specific glutamine restriction may induce adverse effects in unconcerned tissues and therefore glutamine inhibitors have achieved limited success in the clinic so far. Here we report the synthesis and evaluation of a redox-responsive prodrug of 6-Diazo-5-oxo-L-norleucine (redox-DON) for tumor-targeted glutamine inhibition. When applied to treat mice bearing subcutaneous CT26 mouse colon carcinoma, redox-DON exhibited equivalent antitumor efficacy but a greatly improved safety profile, particularly, in spleen and gastrointestinal tract, as compared to the state-of-the-art DON prodrug, JHU083. Furthermore, redox-DON synergized with checkpoint blockade antibodies leading to durable cures in tumor-bearing mice. Our results suggest that redox-DON is a safe and effective therapeutic for tumor-targeted glutamine inhibition showing promise for enhanced metabolic modulatory immunotherapy. The approach of reversible chemical modification may be generalized to other metabolic modulatory drugs that suffer from overt toxicity.
Topics: Animals; Mice; Diazooxonorleucine; Prodrugs; Glutamine; Colonic Neoplasms; Oxidation-Reduction; Tumor Microenvironment
PubMed: 38403173
DOI: 10.1016/j.jconrel.2024.02.031 -
JAMA Network Open Feb 2024Training on the proper use of personal protective equipment (PPE) is critical for infection prevention among health care workers. Traditional methods, such as... (Randomized Controlled Trial)
Randomized Controlled Trial
IMPORTANCE
Training on the proper use of personal protective equipment (PPE) is critical for infection prevention among health care workers. Traditional methods, such as face-to-face and video-based training, can strain resources and present challenges.
OBJECTIVE
To determine the effectiveness of 360° virtual reality (VR) training for PPE donning and doffing compared with face-to-face and video training in enhancing the PPE use skills of prospective health care practitioners.
DESIGN, SETTING, AND PARTICIPANTS
A blinded, prospective, and randomized noninferiority clinical trial was conducted from August to December 2021 at Teikyo University School of Medicine in Tokyo, Japan, with a mixed population of medical students. Participants were second- to fourth-year medicine, medical technology, or pharmacy students aged 20 years or older with no prior PPE training. Participants were randomized into 1 of 3 training groups (VR, face-to-face, or video) based on their enrollment order. An intention-to-treat analysis was conducted.
INTERVENTION
A 30-minute lecture on PPE procedures was delivered to all participants before the training. After the lecture, the VR group trained with an immersive 360° VR tool, the face-to-face group trained with actual PPE, and the video group trained by watching video footage on a computer and a projector. After 3 days, a standardized practical skills test was administered.
MAIN OUTCOMES AND MEASURES
The primary outcome was the mean score on a 20-point practical skills test, and the secondary outcome was the percentage of correct execution.
RESULTS
A total of 91 participants were recruited and randomized into 3 groups: VR (n = 30), face-to-face (n = 30), and video (n = 31) training. After excluding 1 participant due to illness, 90 participants (mean [SD] age, 24.2 [3.15] years; 54 males [60.0%]) completed the assessment. The mean (SD) scores were 17.70 (2.10) points for the VR group, 17.57 (2.45) points for the face-to-face group, and 15.87 (2.90) points for the video group. The VR group demonstrated no significant difference in performance from the face-to-face group. However, the VR group had significantly higher effectiveness than the video group (17.70 vs 15.87 points; P = .02).
CONCLUSIONS AND RELEVANCE
Results of this trial indicate that VR training was as effective as face-to-face training in enhancing PPE donning and doffing skills and was superior to video training. The findings suggest that VR training is a viable resource-conserving training option.
TRIAL REGISTRATION
Japan Registry of Clinical Trials Identifier: jRCT103021029.
Topics: Adult; Humans; Male; Young Adult; Diazooxonorleucine; Health Facilities; Health Personnel; Personal Protective Equipment; Schools; Female
PubMed: 38353953
DOI: 10.1001/jamanetworkopen.2023.55358 -
The Journal of Clinical Investigation Jan 2020Pancreatic ductal adenocarcinoma (PDAC) is considered to be a highly immunosuppressive and heterogenous neoplasm. Despite improved knowledge regarding the genetic...
Pancreatic ductal adenocarcinoma (PDAC) is considered to be a highly immunosuppressive and heterogenous neoplasm. Despite improved knowledge regarding the genetic background of the tumor and better understanding of the tumor microenvironment, immune checkpoint inhibitor therapy (targeting CTLA4, PD1, PDL1) has not been very successful against PDAC. The robust desmoplastic stroma, along with an extensive extracellular matrix (ECM) that is rich in hyaluronan, plays an integral role in this immune evasion. Hexosamine biosynthesis pathway (HBP), a shunt pathway of glycolysis, is a metabolic node in cancer cells that can promote survival pathways on the one hand and influence the hyaluronan synthesis in the ECM on the other. The rate-limiting enzyme of the pathway, glutamine-fructose amidotransferase 1 (GFAT1), uses glutamine and fructose 6-phosphate to eventually synthesize uridine diphosphate N-acetylglucosamine (UDP-GlcNAc). In the current manuscript, we targeted this glutamine-utilizing enzyme by a small molecule glutamine analog (6-diazo-5-oxo-l-norleucine [DON]). Our results showed that DON decreased the self-renewal potential and metastatic ability of tumor cells. Further, treatment with DON decreased hyaluronan and collagen in the tumor microenvironment, leading to an extensive remodeling of the ECM and an increased infiltration of CD8+ T cells. Additionally, treatment with DON sensitized pancreatic tumors to anti-PD1 therapy, resulting in tumor regression and prolonged survival.
Topics: Animals; CD8-Positive T-Lymphocytes; Carcinoma, Pancreatic Ductal; Cell Line, Tumor; Diazooxonorleucine; Female; Hexosamines; Humans; Mice; Mice, Nude; Neoplasm Metastasis; Neoplasm Proteins; Pancreatic Neoplasms; Programmed Cell Death 1 Receptor; Xenograft Model Antitumor Assays
PubMed: 31613799
DOI: 10.1172/JCI127515 -
Journal of Neuropathology and... Mar 2021Medulloblastoma is the most common malignant pediatric brain tumor. Amplification of c-MYC is a hallmark of a subset of poor-prognosis medulloblastoma. MYC upregulates...
Medulloblastoma is the most common malignant pediatric brain tumor. Amplification of c-MYC is a hallmark of a subset of poor-prognosis medulloblastoma. MYC upregulates glutamine metabolism across many types of cancer. We modified the naturally occurring glutamine antagonist 6-diazo-5-oxo-l-norleucine (DON) by adding 2 promoeities to increase its lipophilicity and brain penetration creating the prodrug isopropyl 6-diazo-5-oxo-2-(((phenyl (pivaloyloxy) methoxy) - carbonyl) amino) hexanoate, termed JHU395. This prodrug was shown to have a 10-fold improved CSF-to-plasma ratio and brain-to-plasma ratio relative to DON. We hypothesized that JHU395 would have superior cell penetration compared with DON and would effectively and more potently kill MYC-expressing medulloblastoma. JHU395 treatment caused decreased growth and increased apoptosis in multiple human high-MYC medulloblastoma cell lines at lower concentrations than DON. Parenteral administration of JHU395 in Nu/Nu mice led to the accumulation of micromolar concentrations of DON in brain. Treatment of mice bearing orthotopic xenografts of human MYC-amplified medulloblastoma with JHU395 increased median survival from 26 to 45 days compared with vehicle control mice (p < 0.001 by log-rank test). These data provide preclinical justification for the ongoing development and testing of brain-targeted DON prodrugs for use in medulloblastoma.
Topics: Animals; Apoptosis; Caproates; Cell Line, Tumor; Cerebellar Neoplasms; Diazooxonorleucine; Dose-Response Relationship, Drug; Excitatory Amino Acid Antagonists; Female; Glutamine; Humans; Medulloblastoma; Mice; Mice, Nude
PubMed: 33712838
DOI: 10.1093/jnen/nlab018 -
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 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 -
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 -
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