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Simple Summary: Glioblastoma (GBM) uses the Leloir pathway to catabolize D-Galactose (Gal) for tumor growth. Selective targeting of the Leloir pathway with Gal-based antimetabolites has potential for the treatment of GBM. Here, we tested the effect of a Gal-based antimetabolite, 4-deoxy-4-fluorogalactose (4DFG) on the viability and metabolism of GBM cells in culture. 4DFG is a good Glut3/Glut14 substrate and acts as a potent glioma chemotherapeutic. GBM cell cultures were used to examine toxicity and alterations in glycan composition. 4DFG is moderately potent against GBM cells in vitro (IC50: 125–300 µM). Glycosylation in GBM was disrupted by 4DFG. The effect of 4DFG on D-glucose (Glc) metabolism in GBM cells was assessed by using 13C NMR-based tracer studies. 13C-NMR-based metabolic flux analysis revealed that both glycolytic and mitochondrial metabolic fluxes of [U-13C]Glc were significantly decreased in the presence of 4DFG in GBM cells. Survival analysis in an intracranial mouse model during treatment with 4DFG (6 × 25 mg/kg of 4DFG, intravenously) showed improved outcomes by three-fold (p < 0.01). 4DFG is metabolized by GBM in vitro and in vivo, and is lethal to GBM tumors, but well tolerated in mice. A functional Gal-scavenging pathway in GBM allows Gal-based antimetabolites to act as chemotherapeutics. Background: Glioblastoma (GBM) uses Glut3 and/or Glut14 and the Leloir pathway to catabolize D-Galactose (Gal). UDP-4-deoxy-4-fluorogalactose (UDP-4DFG) is a potent inhibitor of the two key enzymes, UDP-galactose-4-epimerase (GALE) and UDP-Glucose 6-dehydrogenase (UGDH), involved in Gal metabolism and in glycan synthesis. The Gal antimetabolite 4-deoxy-4-fluorogalactose (4DFG) is a good substrate for Glut3/Glut14 and acts as a potent glioma chemotherapeutic. Methods: Primary GBM cell cultures were used to examine toxicity and alterations in glycan composition via lectin binding in fixed cells and by Western blots. Toxicity/efficacy in vivo data was performed in mouse flank and intracranial models. The effect of 4DFG on D-glucose (Glc) metabolism in GBM cells was assessed by using 13C NMR-based tracer studies. Results: 4DFG is moderately potent against GBM cells (IC50: 125–300 µM). GBM glycosylation is disrupted by 4DFG. Survival analysis in an intracranial mouse model showed that treatment with 4DFG (6 × 25 mg/kg of 4DFG, intravenously) improved outcomes by three-fold (p < 0.01). Metabolic flux analysis revealed that both glycolytic and mitochondrial metabolic fluxes of [U-13C]Glc were significantly decreased in the presence of 4DFG in GBM cells. Conclusion: A functional Gal-scavenging pathway in GBM allows Gal-based antimetabolites to act as chemotherapeutics. 4DFG is metabolized by GBM in vitro and in vivo, is lethal to GBM tumors, and is well tolerated in mice. [ABSTRACT FROM AUTHOR]

Some patients taking methotrexate (MTX) or mycophenolate mofetil (MMF) experience intolerable side effects at full doses. We evaluated whether dose reduction affected treatment outcomes in uveitis patients. Subanalysis of the First-line Antimetabolites as Steroid-sparing Treatment (FAST) uveitis trial. Patients were randomized to receive MTX (25 mg weekly) or MMF (3 g daily). A pre-specified dose reduction protocol could be employed for intolerable side effects. Primary analysis was performed at 6 months. 43/194 patients (22%) required dose reduction. 88/151 patients (58%) on maximum doses and 32/43 patients (74%) on reduced doses were deemed treatment successes at 6 months. The odds ratio point estimate (1.60, 95% CI 0.72–3.74) favored dose-reduction but this was not significant. Following reduction, adverse events improved at the subsequent study visit (79 events reduced to 63 events). Dose reduction of antimetabolites was not associated with worse outcomes in this subanalysis of a uveitis trial. [ABSTRACT FROM AUTHOR]

Purpose: Plasma rich in growth factors (PRGF) technology creates blood-derived products with growth factors that promote wound healing and regeneration. The goal of this study was to assess the potential role of PRGF products as wound modulators in trabeculectomy. Our premise is that due to PRGF's regenerative and antifibrotic properties, its use in trabeculectomy may produce a more physiological bleb, without altering IOP reduction. Methods: A retrospective, longitudinal study was conducted in a Hospital in Portugal. Patients with eyes with open angle glaucoma were included. Trabeculectomy was performed on all patients using PRGF membrane (mPRGF) under the conjunctiva, as adjuvant. Data regarding patients' demographics and number of medications used, was collected. Intraocular pressure (IOP) before surgery, 8 days, 1 month, 3 month, 6 month, 9 month and 1 year after surgery was recorded. Bleb morphology was classified according to Moorfields Bleb Grading System 6 months after surgery. Results: Nine eyes of 9 patients were enrolled. Mean age was 71 ± 5.1 years old. Six were male. Mean IOP decreased from 24.0 ± 8.8 mmHg pre-surgery to 12.9 ± 2.6 mmHg at one year follow-up. The number of hypotensive drugs (mean ± SD) was 4.3 ± 0.9 preoperatively and 0.8 ± 1.1 at 1-year. Complete success was defined as IOP equal to or less than 21 mm Hg without ocular hypotensive medications and qualified success as IOP equal to or less than 21 mm Hg with medications. Complete success was 66.7% and qualified success was 100% at 1 year follow-up. Conclusion: In our study, trabeculectomy with mPRGF demonstrated both safety and efficacy. Low values of bleb height (1.6 ± 0.8) were recorded. mPRGF could improve wound healing and produce a more well-tolerated, favourable bleb, avoiding antimetabolite complications. [ABSTRACT FROM AUTHOR]

ABSTRACT: This study aimed to probe if xylooligosaccharide (XOS) could act as an antimetabolite to impact the cell cycle and antibiotic tolerance of avian pathogenic Escherichia coli (APEC). We firstly measured the bacteriostasis of XOS against APEC O78 and its effect on the growth of APEC O78 growing on different medium. Afterwards, the effects of XOS on xylose operon activation along with the cell cycle and antibiotic tolerance of APEC O78 were analyzed. The results showed that XOS caused no inhibitory circle against APEC O78 and did not affect (P > 0.05) the growth of APEC O78 growing on LB medium. Besides, APEC O78 was unable to grow on M9 medium (carbon-free) added with XOS. However, XOS exerted a similar role as xylose in increasing (P < 0.05) the expression of certain xylose operon genes including xylose isomerase (XylA)-encoding gene (xylA) and xylose-binding periplasmic protein (XylF)-encoding gene (xylF) in APEC O78. The molecular docking simulation revealed that the major monomer components (xylobiose, xylotriose and xylotetraose) of XOS had stable binding potentials to both XylA and XylF proteins of E. coli, as supported by the low binding free energy and the formation of considerable hydrogen bonds between them. The subsequent analysis showed that XOS altered certain cell cycle-related genes expression, especially elevated (P < 0.05) nrdB expression and decreased ihfB expression to a degree. Moreover, XOS played a similar role as 2-deoxy-glucose (a glucose analogue serving as a typical antimetabolite) in lowering (P < 0.05) the number of ampicillin-tolerant APEC O78. Collectively, XOS had no direct bacteriostasis against APEC and could not be metabolized/utilized by APEC O78. However, it might become an analogue of xylose and then activate xylose transport- and metabolism-related proteins in APEC O78, thus functioning as a potential antimetabolite and exerting antimetabolic actions. This could at least partially interpret the observed roles of XOS in interfering with the cell cycle and diminishing the antibiotic tolerance of APEC O78. The above findings expand the knowledges about the functions of XOS and provide a basis for exploring novel strategies to reduce the antibiotic tolerance of APEC.

PURPOSE: Some patients taking methotrexate (MTX) or mycophenolate mofetil (MMF) experience intolerable side effects at full doses. We evaluated whether dose reduction affected treatment outcomes in uveitis patients. METHODS: Subanalysis of the First-line Antimetabolites as Steroid-sparing Treatment (FAST) uveitis trial. Patients were randomized to receive MTX (25 mg weekly) or MMF (3 g daily). A pre-specified dose reduction protocol could be employed for intolerable side effects. Primary analysis was performed at 6 months. RESULTS: 43/194 patients (22%) required dose reduction. 88/151 patients (58%) on maximum doses and 32/43 patients (74%) on reduced doses were deemed treatment successes at 6 months. The odds ratio point estimate (1.60, 95% CI 0.72-3.74) favored dose-reduction but this was not significant. Following reduction, adverse events improved at the subsequent study visit (79 events reduced to 63 events). CONCLUSION: Dose reduction of antimetabolites was not associated with worse outcomes in this subanalysis of a uveitis trial.

Capecitabine, the oral prodrug of 5‐fluorouracil, is indicated in people to treat various malignant epithelial cancers. In dogs, capecitabine has not been extensively evaluated. The aim of this retrospective study was to investigate toxicity and preliminary efficacy of single agent capecitabine in dogs with advanced malignant epithelial cancers of any site, for which no effective therapy existed, conventional treatment failed or was declined. Capecitabine was administered orally at 750 mg/m2 from day 1 to 14, followed by 1‐week rest period, given as 3‐week cycles. Safety evaluation was performed after 2 cycles, and every 2–3 cycles thereafter. Tumour response was determined every 2–3 cycles. Twenty‐five dogs with hepatocellular carcinoma (n = 6), lung papillary carcinoma (n = 4), anal sac adenocarcinoma (n = 3), colic adenocarcinoma (n = 2), and other individually represented epithelial cancers (n = 10) were included. Dogs received a median of 4 cycles (range, 2–43) for a median of 84 days (range, 42–913). Toxicity occurred in 17 (68.0%) dogs; the most frequent adverse events were gastrointestinal, with the majority being self‐resolving and of mild grade. Of the 22 dogs with macroscopic disease, 3 (13.6%) achieved partial remission, 16 (72.7%) were stable and 3 (13.6%) progressed; overall clinical benefit rate was 86.4%. Median progression‐free interval was 93 days (95% CI 42–154; range, 1–521) and median tumour‐specific survival was 273 days (95% CI 116–482; range 45–913). These findings suggest that capecitabine is an attractive option for the treatment of several types of carcinomas in dogs. Prospective studies are warranted to optimize the scheduling of capecitabine and confirm its efficacy. [ABSTRACT FROM AUTHOR]

The use of azathioprine (AZA) in human medicine dates back to research conducted in 1975 that led to the development of several drugs, including 6-mercaptopurine. In 1958, it was shown that 6-mercaptopurine decreased the production of antibodies against earlier administered antigens, raising the hypothesis of an immunomodulatory effect. AZA is a prodrug that belongs to the thiopurine group of drugs that behave as purine analogs. After absorption, it is converted into 6-mercaptopurine. Subsequently, it can be degraded through various enzymatic pathways into inactive compounds and biologically active compounds related to the mechanism of action, which has been the subject of study to evaluate a possible antiviral effect. This study aims to examine the metabolism, mechanism of action, and antiviral potential of AZA and its derivatives, exploring AZA impact on antiviral targets and adverse effects through a narrative literature review. Ultimately, the review will provide insights into the antiviral mechanism, present evidence of its in vitro effectiveness against various DNA and RNA viruses, and suggest in vivo studies to further demonstrate its antiviral effects. [ABSTRACT FROM AUTHOR]

Toxoplasmosis is a common protozoan infection that can have severe outcomes in the immunocompromised and during pregnancy, but treatment options are limited. Recently, nucleotide metabolism has received much attention as a target for new antiprotozoal agents and here we focus on pyrimidine salvage by Toxoplasma gondii as a drug target. Whereas uptake of [³H]-cytidine and particularly [³H]-thymidine was at most marginal, [³H]-uracil and [³H]-uridine were readily taken up. Kinetic analysis of uridine uptake was consistent with a single transporter with a Km of 3.3 ± 0.8 µM, which was inhibited by uracil with high affinity (Ki = 1.15 ± 0.07 µM) but not by thymidine or 5-methyluridine, showing that the 5-Me group is incompatible with uptake by T. gondii. Conversely, [³H]-uracil transport displayed a Km of 2.05 ± 0.40 µM, not significantly different from the uracil Ki on uridine transport, and was inhibited by uridine with a Ki of 2.44 ± 0.59 µM, also not significantly different from the experimental uridine Km. The reciprocal, complete inhibition, displaying Hill slopes of approximately -1, strongly suggest that uridine and uracil share a single transporter with similarly high affinity for both, and we designate it uridine/uracil transporter 1 (TgUUT1). While TgUUT1 excludes 5-methyl substitutions, the smaller 5F substitution was tolerated, as 5F-uracil inhibited uptake of [³H]-uracil with a Ki of 6.80 ± 2.12 µM (P > 0.05 compared to uracil Km). Indeed, we found that 5F-Uridine, 5F-uracil and 5F,2’-deoxyuridine were all potent antimetabolites against T. gondii with EC50 values well below that of the current first line treatment, sulfadiazine. In vivo evaluation also showed that 5F-uracil and 5F,2’-deoxyuridine were similarly effective as sulfadiazine against acute toxoplasmosis. Our preliminary conclusion is that TgUUT1 mediates potential new anti-toxoplasmosis drugs with activity superior to the current treatment. [ABSTRACT FROM AUTHOR]

To determine the incidence of all-cause and cancer mortality (CM) in association with immunosuppression. Retrospective cohort study at ocular inflammatory disease (OID) subspecialty centers. We harvested exposure and covariate data retrospectively from clinic inception (earliest in 1979) through 2010 inclusive. Then we ascertained overall and cancer-specific mortalities by National Death Index linkage. We constructed separate Cox models to evaluate overall and CM for each class of immunosuppressant and for each individual immunosuppressant compared with person-time unexposed to any immunosuppression. Patients with noninfectious OID, excluding those with human immunodeficiency infection or preexisting cancer. Tumor necrosis factor (TNF) inhibitors (mostly infliximab, adalimumab, and etanercept); antimetabolites (methotrexate, mycophenolate mofetil, azathioprine); calcineurin inhibitors (cyclosporine); and alkylating agents (cyclophosphamide) were given when clinically indicated in this noninterventional cohort study. Overall mortality and CM. Over 187 151 person-years (median follow-up 10.0 years), during which 15 938 patients were at risk for mortality, we observed 1970 deaths, 435 due to cancer. Both patients unexposed to immunosuppressants (standardized mortality ratio [SMR] = 0.95, 95% confidence interval [CI], 0.90–1.01) and those exposed to immunosuppressants but free of systemic inflammatory diseases (SIDs) (SMR = 1.04, 95% CI, 0.95–1.14) had similar mortality risk to the US population. Comparing patients exposed to TNF inhibitors, antimetabolites, calcineurin inhibitors, and alkylating agents with patients not exposed to any of these, we found that overall mortality (adjusted hazard ratio [aHR] = 0.88, 0.89, 0.90, 1.11) and CM (aHR = 1.25, 0.89, 0.86, 1.23) were not significantly increased. These results were stable in sensitivity analyses whether excluding or including patients with SID, across 0-, 3-, or 5-year lags and across quartiles of immunosuppressant dose and duration. Our results, in a cohort where the indication for treatment was proven unassociated with mortality risk, found that commonly used immunosuppressants—especially the antimetabolites methotrexate, mycophenolate mofetil, and azathioprine; the TNF inhibitors adalimumab and infliximab, and cyclosporine—were not associated with increased overall and CM over a median cohort follow-up of 10.0 years. These results suggest the safety of these agents with respect to overall and CM for patients treated with immunosuppression for a wide range of inflammatory diseases. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article. [ABSTRACT FROM AUTHOR]

PurposeSub-analysis of the FAST Trial comparing change in CD4 (∆CD4) from baseline through 12 months in uveitis patients treated with mycophenolate mofetil (MMF) and methotrexate (MTX).MethodsPatients were randomly allocated to 1.5 g twice daily MMF or 25 mg weekly MTX. Individuals with CD4 counts at baseline, 6 months (or treatment failure prior), and 12 months (or treatment failure between 6 and 12 months) were included. The association between treatment and ∆CD4 (cells/μL) was analyzed using multivariable linear regression.ResultsThere was no significant difference in ∆CD4 between MMF and MTX at 6 months (-31.7 cells/μL for MMF compared to MTX; 95% CI: -358.2 to 294.8, P = .85) and 12 months (-78.3 cells/μL for MMF compared to MTX; 95% CI: -468.0 to 311.3; P = .69).ConclusionThere was no significant difference in ∆CD4 between MMF and MTX from baseline to 12 months, suggesting that MMF does not confer additional risk of CD4 lymphopenia in uveitic patients.ClinicalTrials.gov Identifier: NCT01829295.

Toxoplasmosis is a common protozoan infection that can have severe outcomes in the immunocompromised and during pregnancy, but treatment options are limited. Recently, nucleotide metabolism has received much attention as a target for new antiprotozoal agents and here we focus on pyrimidine salvage by Toxoplasma gondii as a drug target. Whereas uptake of [3H]-cytidine and particularly [3H]-thymidine was at most marginal, [3H]-uracil and [3H]-uridine were readily taken up. Kinetic analysis of uridine uptake was consistent with a single transporter with a Km of 3.3 ± 0.8 µM, which was inhibited by uracil with high affinity (Ki = 1.15 ± 0.07 µM) but not by thymidine or 5-methyluridine, showing that the 5-Me group is incompatible with uptake by T. gondii. Conversely, [3H]-uracil transport displayed a Km of 2.05 ± 0.40 µM, not significantly different from the uracil Ki on uridine transport, and was inhibited by uridine with a Ki of 2.44 ± 0.59 µM, also not significantly different from the experimental uridine Km. The reciprocal, complete inhibition, displaying Hill slopes of approximately -1, strongly suggest that uridine and uracil share a single transporter with similarly high affinity for both, and we designate it uridine/uracil transporter 1 (TgUUT1). While TgUUT1 excludes 5-methyl substitutions, the smaller 5F substitution was tolerated, as 5F-uracil inhibited uptake of [3H]-uracil with a Ki of 6.80 ± 2.12 µM (P > 0.05 compared to uracil Km). Indeed, we found that 5F-Uridine, 5F-uracil and 5F,2’-deoxyuridine were all potent antimetabolites against T. gondii with EC50 values well below that of the current first line treatment, sulfadiazine. In vivo evaluation also showed that 5F-uracil and 5F,2’-deoxyuridine were similarly effective as sulfadiazine against acute toxoplasmosis. Our preliminary conclusion is that TgUUT1 mediates potential new anti-toxoplasmosis drugs with activity superior to the current treatment.

Background: The nucleoside FF‐10502‐01, structurally similar to but with different biologic effects than gemcitabine, shows promising activity both alone and combined with cisplatin in preclinical gemcitabine‐resistant tumor models. We conducted an open‐label, single‐arm, 3 + 3 first‐in‐human trial to explore the safety, tolerability, and antitumor activity of FF‐10502‐01 in patients with solid tumors. Methods: Patients with inoperable metastatic tumors refractory to standard therapies were enrolled. Escalating intravenous FF‐10502‐01 doses (8–135 mg/m2) were administered weekly for 3 weeks in 28‐day cycles until progressive disease or unacceptable toxicity was observed. Three expansion cohorts were subsequently evaluated. Results: A phase 2 dose of 90 mg/m2 was determined after evaluating 40 patients. Dose‐limiting toxicities included hypotension and nausea. Phase 2a enrolled patients with cholangiocarcinoma (36), gallbladder cancer (10), and pancreatic/other tumors (20). Common adverse events were grade 1–2 rash, pruritus, fever, and fatigue. Grade 3 or 4 hematologic toxicities were observed at low incidences, including thrombocytopenia (5.1%) and neutropenia (2%). Confirmed partial responses (PRs) occurred in five patients with gemcitabine‐refractory tumors, including three with cholangiocarcinoma and one each with gallbladder and urothelial cancer. Median progression‐free and overall survival rates in patients with cholangiocarcinoma were 24.7 and 39.1 weeks, respectively. Prolonged progression‐free survival in patients with cholangiocarcinoma was associated with BAP1 and PBRM1 mutations. Conclusion: FF‐10502‐01 was well tolerated with manageable side effects and limited hematologic toxicity. Durable PRs and disease stabilizations were observed in heavily pretreated biliary tract patients who had received prior gemcitabine. FF‐10502‐01 is distinct from gemcitabine and may represent an effective therapy. A phase 1/2a study of FF‐10502‐01, a nucleoside structurally similar to gemcitabine but with distinct biologic effects, demonstrates activity in patients with gemcitabine‐refractory tumors, including cholangiocarcinoma; this compares favorably to second‐line FOLFOX chemotherapy in patients with advanced biliary cancer. Prolonged progression‐free survival in cholangiocarcinoma was associated with BAP1 and PBRM1 mutations, which may be important for patient selection. [ABSTRACT FROM AUTHOR]

Odontogenic keratocyst (OKC) is an aggressive cystic lesion of the jaw with high growth and recurrence. Patients are usually asymptomatic and detected during routine radiographic examination. Management of OKC varies from conservative procedures like simple Enucleation and peripheral ostectomy to aggressive resection. More attention is given to new treatment protocols to form them simple and successful. 5 fluorouracil is an anti-metabolite used to treat basal cell carcinoma and other malignancies act by inhibiting thymidylate synthase an enzyme required for DNA synthesis causing cell death. This is a case report of a 40-year-old female patient with OKC treated with topical 5 fluorouracil after enucleation, has less morbidity minimal recurrence, and low cost. [ABSTRACT FROM AUTHOR]

The use of azathioprine (AZA) in human medicine dates back to research conducted in 1975 that led to the development of several drugs, including 6-mercaptopurine. In 1958, it was shown that 6-mercaptopurine decreased the production of antibodies against earlier administered antigens, raising the hypothesis of an immunomodulatory effect. AZA is a prodrug that belongs to the thiopurine group of drugs that behave as purine analogs. After absorption, it is converted into 6-mercaptopurine. Subsequently, it can be degraded through various enzymatic pathways into inactive compounds and biologically active compounds related to the mechanism of action, which has been the subject of study to evaluate a possible antiviral effect. This study aims to examine the metabolism, mechanism of action, and antiviral potential of AZA and its derivatives, exploring AZA impact on antiviral targets and adverse effects through a narrative literature review. Ultimately, the review will provide insights into the antiviral mechanism, present evidence of its in vitro effectiveness against various DNA and RNA viruses, and suggest in vivo studies to further demonstrate its antiviral effects.

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Among the scarce validated drug targets against Chagas disease (CD), caused by Trypanosoma cruzi, the parasite's nucleoside salvage system has recently attracted considerable attention. Although the trypanocidal activity of tubercidin (7-deazapurine) has long been known, the identification of a class of 7-substituted tubercidin analogs with potent in vitro and in vivo activity and much-enhanced selectivity has made nucleoside analogs among the most promising lead compounds against CD. Here, we investigate the recently identified TcrNT2 nucleoside transporter and its potential role in antimetabolite chemotherapy. TcrNT2, expressed in a Leishmania mexicana cell line lacking the NT1 nucleoside transporter locus, displayed very high selectivity and affinity for thymidine with a Km of 0.26 ± 0.05 µM. The selectivity was explained by interactions of 2-oxo, 4-oxo, 5-Me, 3′-hydroxy and 5′-hydroxy with the transporter binding pocket, whereas a hydroxy group at the 2′ position was deleterious to binding. This made 5-halogenated 2′-deoxyuridine analogues good substrates but 5-F-2′-deoxyuridine displayed disappointing activity against T. cruzi trypomastigotes. By comparing the EC50 values of tubercidin and its 7-substituted analogues against L. mexicana Cas9, Cas9ΔNT1 and Cas9ΔNT1+TcrNT2 it was shown that TcrNT2 can take up tubercidin and, at a minimum, a subset of the analogs. [ABSTRACT FROM AUTHOR]

This study aimed to probe if xylooligosaccharide (XOS) could act as an antimetabolite to impact the cell cycle and antibiotic tolerance of avian pathogenic Escherichia coli (APEC). We firstly measured the bacteriostasis of XOS against APEC O78 and its effect on the growth of APEC O78 growing on different medium. Afterwards, the effects of XOS on xylose operon activation along with the cell cycle and antibiotic tolerance of APEC O78 were analyzed. The results showed that XOS caused no inhibitory circle against APEC O78 and did not affect (P > 0.05) the growth of APEC O78 growing on LB medium. Besides, APEC O78 was unable to grow on M9 medium (carbon-free) added with XOS. However, XOS exerted a similar role as xylose in increasing (P < 0.05) the expression of certain xylose operon genes including xylose isomerase (XylA)-encoding gene (xylA) and xylose-binding periplasmic protein (XylF)-encoding gene (xylF) in APEC O78. The molecular docking simulation revealed that the major monomer components (xylobiose, xylotriose and xylotetraose) of XOS had stable binding potentials to both XylA and XylF proteins of E. coli, as supported by the low binding free energy and the formation of considerable hydrogen bonds between them. The subsequent analysis showed that XOS altered certain cell cycle-related genes expression, especially elevated (P < 0.05) nrdB expression and decreased ihfB expression to a degree. Moreover, XOS played a similar role as 2-deoxy-glucose (a glucose analogue serving as a typical antimetabolite) in lowering (P < 0.05) the number of ampicillin-tolerant APEC O78. Collectively, XOS had no direct bacteriostasis against APEC and could not be metabolized/utilized by APEC O78. However, it might become an analogue of xylose and then activate xylose transport- and metabolism-related proteins in APEC O78, thus functioning as a potential antimetabolite and exerting antimetabolic actions. This could at least partially interpret the observed roles of XOS in interfering with the cell cycle and diminishing the antibiotic tolerance of APEC O78. The above findings expand the knowledges about the functions of XOS and provide a basis for exploring novel strategies to reduce the antibiotic tolerance of APEC., Competing Interests: DISCLOSURES The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Trypanosoma brucei, the causative agent for human African trypanosomiasis, is an emerging ergosterol-dependent parasite that produces chokepoint enzymes, sterol methyltransferases (SMT), not synthesized in their animal hosts that can regulate cell viability. Here, we report the lethal effects of two recently described natural product antimetabolites that disrupt Acanthamoeba sterol methylation and growth, cholesta-5,7,22,24-tetraenol (CHT) and ergosta-5,7,22,24(28)-tetraenol (ERGT) that can equally target T. brucei. We found that CHT/ERGT inhibited cell growth in vitro, yielding EC50 values in the low nanomolar range with washout experiments showing cidal activity against the bloodstream form, consistent with their predicted mode of suicide inhibition on SMT activity and ergosterol production. Antimetabolite treatment generated altered T. brucei cell morphology and death rapidly within hours. Notably, in vivo ERGT/CHT protected mice infected with T. brucei, doubling their survival time following daily treatment for 8–10 days at 50 mg/kg or 100 mg/kg. The current study demonstrates a new class of lead antibiotics, in the form of common fungal sterols, for antitrypanosomal drug development. [ABSTRACT FROM AUTHOR]

To evaluate the outcomes of uveitic macular edema at 6 and 12 months in patients treated with methotrexate or mycophenolate mofetil. Subanalysis of a block-randomized, observer-masked, multicenter clinical trial. Patients were enrolled in the First-line Antimetabolites as Steroid-sparing Treatment (FAST) Uveitis Trial between August 2013 and August 2017. Patients were randomized to oral methotrexate 25 mg weekly or mycophenolate mofetil 1.5 g twice daily for 12 months, along with a corticosteroid taper. In addition to standardized clinical examination, all patients underwent spectral-domain OCT imaging at each visit. At the 6-month primary end point, patients who achieved treatment success continued the same treatment for a subsequent 6 months, and treatment failures switched to the other treatment group. Prespecified 6-month primary outcome and 12-month outcomes of central subfield thickness and visual acuity. Of 216 patients in the FAST Trial, 42 eyes (30 patients) in the methotrexate group and 55 eyes (41 patients) in the mycophenolate group had uveitic macular edema. Baseline median central subfield thickness was 359 μm and 342 μm in the methotrexate and mycophenolate groups, respectively. At 12 months, for those who stayed on the same treatment, macular thickness decreased from baseline by 30.5 μm (interquartile range [IQR], −132.3 to 4.0) and 54 μm (IQR, −95.5 to −4.5) in the methotrexate and mycophenolate groups, respectively (P = 0.73). In patients who switched treatment at 6 months, macular thickness decreased from baseline by 12.5 μm (IQR, −32.3 to −0.5) and 50 μm (IQR, −181.0 to −10.0) in the methotrexate and mycophenolate groups, respectively (P = 0.34). At 12 months, 7 of 19 eyes (37%) on methotrexate had resolution of macular edema compared with 15 of 25 eyes (60%) on mycophenolate (P = 0.10). For those who switched treatments, 8 of 17 eyes (47%) on methotrexate and 6 of 11 eyes (55%) on mycophenolate had resolution of macular edema (P = 0.92). Treatment with methotrexate or mycophenolate mofetil for uveitic macular edema results in similar improvements in macular thickness at 6 and 12 months. At 12 months, approximately half of eyes in each antimetabolite group still had persistent macular edema. [ABSTRACT FROM AUTHOR]

PurposeTo conduct a Bayesian analysis of a randomized clinical trial (RCT) for non-infectious uveitis using expert opinion as a subjective prior belief.MethodsA RCT was conducted to determine which antimetabolite, methotrexate or mycophenolate mofetil, is more effective as an initial corticosteroid-sparing agent for the treatment of intermediate, posterior, and pan-uveitis. Before the release of trial results, expert opinion on the relative effectiveness of these two medications was collected via online survey. Members of the American Uveitis Society executive committee were invited to provide an estimate for the relative decrease in efficacy with a 95% credible interval (CrI). A prior probability distribution was created from experts' estimates. A Bayesian analysis was performed using the constructed expert prior probability distribution and the trial's primary outcome.ResultsA total of 11 of the 12 invited uveitis specialists provided estimates. Eight of 11 experts (73%) believed mycophenolate mofetil is more effective. The group prior belief was that the odds of treatment success for patients taking mycophenolate mofetil were 1.4-fold the odds of those taking methotrexate (95% CrI 0.03-45.0). The odds of treatment success with mycophenolate mofetil compared to methotrexate was 0.4 from the RCT (95% confidence interval 0.1-1.2) and 0.7 (95% CrI 0.2-1.7) from the Bayesian analysis.ConclusionsA Bayesian analysis combining expert belief with the trial's result did not indicate preference for one drug. However, the wide credible interval leaves open the possibility of a substantial treatment effect. This suggests clinical equipoise necessary to allow a larger, more definitive RCT.

Summary: Background RX-3117 is an oral small molecule antimetabolite, cyclopentyl pyrimidyl nucleoside that is activated by cancer cells over-expressing uridine cytidine kinase 2 (UCK2). Single agent RX-3117 demonstrated efficacy in a phase I trial in patients with metastatic (met) pancreatic adenocarcinoma (PC). RX-3117 plus nab-paclitaxel (nab-Pac) was evaluated as a first line treatment in met-PC cancer. Methods This was a multicenter open label phase I/II 2-stage study investigating the combination of RX3117 plus nab-Pac in the frontline treatment of patients with met-PC. The phase I portion comprised a dose de-escalation design with primary objectives of determining the safety, tolerability and recommended phase 2 dose (RP2D) of RX-3117 (orally 700, 600, or 500 mg/day for 5 consecutive days with 2 days off/week) plus nab-Pac (intravenous (IV) 125 mg/m2 once weekly) for 3 weeks with 1 week off per a 4-week cycle. The primary objective was to determine the antitumor efficacy. Results 46 patients were enrolled (22 male/24 female; median age 67; 91% Caucasian). The RP2D of RX-3117 plus nab-Pac was 700 mg/day. No dose-limiting toxicities were observed (DLTs). The overall response rate (ORR) was 23.1% and disease control rate (DCR) 74.4%. RX-3117 pharmacokinetics (PK) results were similar to previously reported monotherapy phase 1 trial. All patients experienced a treatment emergent adverse event (TEAE) with the most common diarrhea, nausea, and fatigue.10.9% of patients experienced a serious adverse event (SAE) related to the combination. Conclusion RX-3117 plus nab-Pac in newly diagnosed met-PC patients demonstrated tolerability, safety, and early treatment efficacy. [ABSTRACT FROM AUTHOR]

Scleritis is a severe, vision-threatening ocular inflammation often associated with systemic diseases that carry high risks of morbidity. Timely diagnosis and management are crucial to prevent sequela. This review encompasses the etiology, pathophysiology, classification, diagnosis, and treatment of scleritis with an emphasis on novel diagnostic and treatment modalities. A review of the literature was performed using the keywords 'scleritis,' 'autoimmune diseases,' 'non-steroidal anti-inflammatory drugs,' 'antimetabolite,' 'immunomodulatory therapy,' 'tumor necrosis factor alpha inhibitors,' biologic response modifier' and 'optical coherence tomography.' Scleritis is mainly a clinical diagnosis. Nevertheless, multimodal imaging may be used in diagnostically challenging cases. New approaches such as anterior segment optical coherence tomography (OCT), OCT angiography (OCTA), and ultrasound biomicroscopy (UBM) may serve as more objective measures to diagnose and monitor scleritis patients. The etiology, severity, anatomical location, and associated systemic inflammatory diseases should be considered when determining scleritis treatment. Currently, first-line treatment in low grade non-necrotizing anterior scleritis is usually non-steroidal anti-inflammatory drugs (NSAIDs) and/or topical/systemic corticosteroids. In non-responsive cases, systemic immunomodulatory therapy (IMT) is recommended. Novel treatment with biologic response modifiers (BRMs) is promising in refractory scleritis. Further studies are needed to evaluate efficiency and safety of BRMs. [ABSTRACT FROM AUTHOR]

Aims: To compare the long-term safety and efficacy of subconjunctival injection mitomycin C(MMC) with conventional sponge applied MMC during trabeculectomy., Methods and Material: Retrospective analysis of 98 eyes of 90 patients who underwent trabeculectomy with Mitomycin C were divided into two groups, group 1- sponge (n = 52) and group 2- Injection(n = 46). Follow-up data were collected on day one, day 15, one month, three months, six months, one year, two years and three years. Data from baseline and follow-up visits were analyzed and compared to study the significant difference in intraocular pressure (IOP), number of antiglaucoma medications (AGM) and best corrected visual acuity (BCVA) . P -value of <0.05 was considered statistically significant., Results: Mean preop IOP was 34.61 ± 13.3 mmHg in group one and 33.07 ± 9.6 mmHg in group two, which reduced to 11.43 ± 3.2 and 11.59 ± 3.2 mmHg at three years ( p  < 0.001 in both groups) with no significant difference between the groups. Mean number of preoperative AGM was 2.28 ± 0.8 and 2.42 ± 0.7 in group one and two respectively which reduced to 1.19 ± 1.1( p  = 0.405) and 0.88 ± 0.9( p  = 0.001) at three years. Complete and overall success rates (complete + qualified) were 59.3% and 78.9% in group one and 60.9% and 80.4% in group two at three years. No statistically significant difference was found in complication rates, post-operative interventions, and final visual outcome in both groups., Conclusions: Subconjunctival Injection MMC was a safe and effective alternative to sponge application with comparable long term surgical outcomes., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

5′-Methylthioadenosine (MTA) is a natural substrate of MTA phosphorylase (MTAP) and is converted to adenine via a salvage pathway for AMP production in normal healthy cells. The lack of MTAP expression in many solid tumors and hematologic malignancies compared to normal healthy cells has been explored in a potential therapeutic strategy to selectively target tumor cells using antimetabolites such as 5-fluorouracil (5-FU) and 6-thioguanine (6-TG) while protecting normal healthy cells with MTA. Herein, a series of carbamate prodrugs, namely the N-(alkyloxy)carbonyl-MTA derivatives 2a-f, was designed, synthesized, and evaluated as potential prodrugs of MTA. All carbamate prodrugs were stable in phosphate buffer, pH 7.4 at 37 °C. In the presence of mouse liver microsomes, the prodrugs were converted to MTA at varying rates with the hexyl and butyl carbamates 2a and 2b most readily activated (t1/2 of 1.2 and 9.4 h, respectively). The activation was shown to be mediated by carboxyesterases present in mouse liver microsomes. [ABSTRACT FROM AUTHOR]

Summary: Objectives Malignant pleural mesothelioma (MPM) is an occupational disease mainly due to asbestos exposure. Effective therapies for MPM are lacking, making this tumour type a fatal disease. Materials and Methods In order to meet this need and in view of a future "drug repositioning" approach, here we screened five MPM (Mero-14, Mero-25, IST-Mes2, NCI-H28 and MSTO-211H) and one SV40-immortalized mesothelial cell line (MeT-5A) as a non-malignant model, with a library of 1170 FDA-approved drugs. Results Among several potential compounds, we found that fludarabine (F-araA) and, to a lesser extent, risedronic acid (RIS) were cytotoxic in MPM cells, in comparison to the non-malignant Met-5A cells. In particular, F-araA reduced the proliferation and the colony formation ability of the MPM malignant cells, in comparison to the non-malignant control cells, as demonstrated by proliferation and colony formation assays, in addition to measurement of the phospho-ERK/total-ERK ratio. We have shown that the response to F-araA was not dependent upon the expression of DCK and NT5E enzymes, nor upon their functional polymorphisms (rs11544786 and rs2295890, respectively). Conclusion This drug repositioning screening approach has identified that F-araA could be therapeutically active against MPM cells, in addition to other tumour types, by inhibiting STAT1 expression and nucleic acids synthesis. Further experiments are required to fully investigate this. [ABSTRACT FROM AUTHOR]

Trypanosoma brucei, the causative agent for human African trypanosomiasis, is an emerging ergosterol-dependent parasite that produces chokepoint enzymes, sterol methyltransferases (SMT), not synthesized in their animal hosts that can regulate cell viability. Here, we report the lethal effects of two recently described natural product antimetabolites that disrupt Acanthamoeba sterol methylation and growth, cholesta-5,7,22,24-tetraenol (CHT) and ergosta-5,7,22,24(28)-tetraenol (ERGT) that can equally target T. brucei. We found that CHT/ERGT inhibited cell growth in vitro, yielding EC50 values in the low nanomolar range with washout experiments showing cidal activity against the bloodstream form, consistent with their predicted mode of suicide inhibition on SMT activity and ergosterol production. Antimetabolite treatment generated altered T. brucei cell morphology and death rapidly within hours. Notably, in vivo ERGT/CHT protected mice infected with T. brucei, doubling their survival time following daily treatment for 8–10 days at 50 mg/kg or 100 mg/kg. The current study demonstrates a new class of lead antibiotics, in the form of common fungal sterols, for antitrypanosomal drug development.

Despite decades of dedicated research, there remains a dire need for new drugs against tuberculosis (TB). Current therapies are generations old and problematic. Resistance to these existing therapies results in an ever-increasing burden of patients with disease that is difficult or impossible to treat. Novel chemical entities with new mechanisms of action are therefore earnestly required. The biosynthesis of coenzyme A (CoA) has long been known to be essential in Mycobacterium tuberculosis (Mtb), the causative agent of TB. The pathway has been genetically validated by seminal studies in vitro and in vivo. In Mtb, the CoA biosynthetic pathway is comprised of nine enzymes: four to synthesize pantothenate (Pan) from l-aspartate and α-ketoisovalerate; five to synthesize CoA from Pan and pantetheine (PantSH). This review gathers literature reports on the structure/mechanism, inhibitors, and vulnerability of each enzyme in the CoA pathway. In addition to traditional inhibition of a single enzyme, the CoA pathway offers an antimetabolite strategy as a promising alternative. In this review, we provide our assessment of what appear to be the best targets, and, thus, which CoA pathway enzymes present the best opportunities for antitubercular drug discovery moving forward.

Aim: To report on the outcome of subsequent interventions after failed initial intervention for primary congenital glaucoma (PCG)., Methods: Retrospective chart review of children presenting with PCG and failed the initial glaucoma surgery in Alexandria Main University Hospital from 2005 to 2017. The data included demographics, preoperative, operative and postoperative clinical characteristics. Success was defined as IOP<16mmHg and <20% from the presenting IOP and C/D ratio like or better than presentation., Results: The charts of 531 (260 right, 49%) eyes of 360 (224 males, 62%) children presenting with PCG and failed the initial glaucoma surgery (58 [31 right, 53%] eyes [10.9%] of 50 [28 males, 56%] children) revealed that at initial presentation, the mean±standard deviation (range, median) of the age of the children subjected to one successful glaucoma procedure and the study children was 8.6±11.7 (0.6-109, 5.2) and 4.9±6.1 (0.5-34.4, 3.0) months, respectively. Each of the study eyes was subjected to 2.6±0.8 (2-5.2) glaucoma procedures. The mean±standard deviation (range, median) duration between the initial and second glaucoma surgery and the duration of follow-up was 6.9±7.8 (0.7-39,3.9) and 61.5±32.1 (12.0-139.1, 60.1) months, respectively. At the final follow-up visit success was reported in 41 (70.1%) eyes by IOP<16mmHg criterion, 39 (67.2%) eyes by IOP>20% reduction criterion and in 28 (out of 35 eyes, 80.0%) by the optic nerve condition (C/D ratio) criterion. Success by all 3 criteria was reported in 25 (out of 35 eyes, 71%) eyes., Conclusions: A repeat glaucoma surgical procedure maybe needed in up to 11% of operated PCG eyes, with the subsequent glaucoma surgical procedures being successful by about 70%., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Despite decades of dedicated research, there remains a dire need for new drugs against tuberculosis (TB). Current therapies are generations old and problematic. Resistance to these existing therapies results in an ever-increasing burden of patients with disease that is difficult or impossible to treat. Novel chemical entities with new mechanisms of action are therefore earnestly required. The biosynthesis of coenzyme A (CoA) has long been known to be essential in Mycobacterium tuberculosis (Mtb), the causative agent of TB. The pathway has been genetically validated by seminal studies in vitro and in vivo. In Mtb, the CoA biosynthetic pathway is comprised of nine enzymes: four to synthesize pantothenate (Pan) from l-aspartate and α-ketoisovalerate; five to synthesize CoA from Pan and pantetheine (PantSH). This review gathers literature reports on the structure/mechanism, inhibitors, and vulnerability of each enzyme in the CoA pathway. In addition to traditional inhibition of a single enzyme, the CoA pathway offers an antimetabolite strategy as a promising alternative. In this review, we provide our assessment of what appear to be the best targets, and, thus, which CoA pathway enzymes present the best opportunities for antitubercular drug discovery moving forward. [ABSTRACT FROM AUTHOR]

Colorectal cancer (CRC) is the third leading cause of death in men and the fourth in women worldwide and is characterized by deranged cellular energetics. Thymoquinone, an active component from Nigella sativa, has been extensively studied against cancer, however, its role in affecting deregulated cancer metabolism is largely unknown. Further, the phosphoinositide 3-kinase (PI3K) pathway is one of the most activated pathways in cancer and its activation is central to most deregulated metabolic pathways for supporting the anabolic needs of growing cancer cells. Herein, we provide evidence that thymoquinone inhibits glycolytic metabolism (Warburg effect) in colorectal cancer cell lines. Further, we show that such an abrogation of deranged cell metabolism was due, at least in part, to the inhibition of the rate-limiting glycolytic enzyme, Hexokinase 2 (HK2), via modulating the PI3/AKT axis. While overexpression of HK2 showed that it is essential for fueling glycolytic metabolism as well as sustaining tumorigenicity, its pharmacologic and/or genetic inhibition led to a reduction in the observed effects. The results decipher HK2 mediated inhibitory effects of thymoquinone in modulating its glycolytic metabolism and antitumor effects. In conclusion, we provide evidence of metabolic perturbation by thymoquinone in CRC cells, highlighting its potential to be used/repurposed as an antimetabolite drug, though the latter needs further validation utilizing other suitable cell and/or preclinical animal models.

Infections due to Gram-negative bacteria are increasingly dangerous due to the spread of multi-drug resistant strains, emphasizing the urgent need for new antibiotics with alternative modes of action. We have previously identified a novel class of antibacterial agents, thioacetamide-triazoles, using an antifolate targeted screen and determined their mode of action which is dependent on activation by cysteine synthase A. Herein, we report a detailed examination of the anti-E. coli structure–activity relationship of the thioacetamide-triazoles. Analogs of the initial hit compounds were synthesized to study the contribution of the aryl, thioacetamide, and triazole sections. A clear structure–activity relationship was observed generating compounds with excellent inhibition values. Substitutions to the aryl ring were generally best tolerated, including the introduction of thiazole and pyridine heteroaryl systems. Substitutions to the central thioacetamide linker section were more nuanced; the introduction of a methyl branch to the thioacetamide linker substantially decreased antibacterial activity, but the isomeric propionamide and N-benzamide systems retained activity. Changes to the triazole portion of the molecule dramatically decreased the antibacterial activity, further indicating that 1,2,3-triazole is critical for potency. From these studies, we have identified new lead compounds with desirable in-vitro ADME properties and in-vivo pharmacokinetic properties.

Broad-spectrum antiviral therapies hold promise as a first-line defense against emerging viruses by blunting illness severity and spread until vaccines and virus-specific antivirals are developed. The nucleobase favipiravir, often discussed as a broad-spectrum inhibitor, was not effective in recent clinical trials involving patients infected with Ebola virus or SARS-CoV-2. A drawback of favipiravir use is its rapid clearance before conversion to its active nucleoside-5′-triphosphate form. In this work, we report a synergistic reduction of flavivirus (dengue, Zika), orthomyxovirus (influenza A), and coronavirus (HCoV-OC43 and SARS-CoV-2) replication when the nucleobases favipiravir or T-1105 were combined with the antimetabolite 6-methylmercaptopurine riboside (6MMPr). The 6MMPr/T-1105 combination increased the C-U and G-A mutation frequency compared to treatment with T-1105 or 6MMPr alone. A further analysis revealed that the 6MMPr/T-1105 co-treatment reduced cellular purine nucleotide triphosphate synthesis and increased conversion of the antiviral nucleobase to its nucleoside-5′-monophosphate, -diphosphate, and -triphosphate forms. The 6MMPr co-treatment specifically increased production of the active antiviral form of the nucleobases (but not corresponding nucleosides) while also reducing levels of competing cellular NTPs to produce the synergistic effect. This in-depth work establishes a foundation for development of small molecules as possible co-treatments with nucleobases like favipiravir in response to emerging RNA virus infections.

Summary: Endemism and rarity have long intrigued scientists. We focused on a rare endemic and critically‐endangered species in a global biodiversity hotspot, Grevillea thelemanniana (Proteaceae).We carried out plant and soil analyses of four Proteaceae, including G. thelemanniana, and combined these with glasshouse studies. The analyses related to hydrology and plant water relations as well as soil nutrient concentrations and plant nutrition, with an emphasis on sodium (Na) and calcium (Ca).The local hydrology and matching plant traits related to water relations partially accounted for the distribution of the four Proteaceae. What determined the rarity of G. thelemanniana, however, was its accumulation of Ca. Despite much higher total Ca concentrations in the leaves of the rare G. thelemanniana than in the common Proteaceae, very few Ca crystals were detected in epidermal or mesophyll cells. Instead of crystals, G. thelemanniana epidermal cell vacuoles contained exceptionally high concentrations of noncrystalline Ca. Calcium ameliorated the negative effects of Na on the very salt‐sensitive G. thelemanniana. Most importantly, G. thelemanniana required high concentrations of Ca to balance a massively accumulated feeding‐deterrent carboxylate, trans‐aconitate.This is the first example of a calcicole species accumulating and using Ca to balance accumulation of an antimetabolite. [ABSTRACT FROM AUTHOR]

Scoring changes in enzyme or pathway performance by their effect on growth behavior is a widely applied strategy for identifying improved biocatalysts. While in directed evolution this strategy is powerful in removing non-functional catalysts in selections, measuring subtle differences in growth behavior remains difficult at high throughput, as it is difficult to focus metabolic control on only one or a few enzymatic steps over the entire process of growth-based discrimination. Here, we demonstrate successful miniaturization of a growth-based directed enzyme evolution process. For cultivation of library clones we employed optically clear gel-like microcarriers of nanoliter volume (NLRs) as reaction vessels and used fluorescence-assisted particle sorting to estimate the growth behavior of each of the gel-embedded clones in a highly parallelized fashion. We demonstrate that the growth behavior correlates with the desired improvements in enzyme performance and that we can fine-tune selection stringency by including an antimetabolite in the assay. As a model enzyme reaction, we improve the racemization of ornithine, a possible starting block for the large-scale synthesis of sulphostin, by a broad-spectrum amino acid racemase and confirm the discriminatory power by showing that even moderately improved enzyme variants can be readily identified. Image 1 • Screening for differences in growth is a powerful strategy in directed evolution. • Growth of bacterial strains can be robustly measured in nanoliter reactors. • Antimetabolite selection can be used as a powerful strategy in enzyme evolution. • A racemase with a roughly 3-fold improved catalytic efficiency was isolated. [ABSTRACT FROM AUTHOR]

Developing novel strategies against foodborne pathogens, like Listeria monocytogenes , is crucial due to their growing resistance to current hurdles and disinfection protocols. Disruption of the cobalamin biosynthesis pathway revealed the importance of vitamin B 12 (B 12) in L. monocytogenes tolerance to cold and copper stress, suggesting that B 12 analogues have potential as hurdles against it on food. In 2021, 10-Br-methyl cobalamin (10-Br-MeCbl) was introduced as an L. monocytogenes antimetabolite. Herein, we re-evaluated 10-Br-MeCbl and tested seven related B 12 analogues against six L. monocytogenes strains and a B 12 auxotrophic Lactobacillus delbrueckii strain. No analogue, including 10-Br-MeCbl, was inhibitory to L. monocytogenes. In contrast, 10-Br-MeCbl, 10-Br-CNCbl, 10-Br-PhCbl, and 10-Br-CNCbl- c -lactam inhibited L. delbrueckii growth (13–27%) at concentrations 50-folds higher than B 12. This inhibitory activity was lost under conditions of B 12 abundance, indicating competitive inhibition. The activity of phenylcobalamin- c -lactam against L. delbrueckii differed compared to a previous study, emphasizing that the antimicrobial activity of B 12 derivatives is not universal and must be examined for each species under the application conditions. Overall, while this study illustrates the potential of B 12 antimetabolites as antimicrobials, it also demonstrates that other classes of B 12 antimetabolites and/or improved strategies are required for tackling pathogens like L. monocytogenes. • Novel strategies are needed to combat foodborne pathogens. • No tested B 12 analogue, including 10-Br-MeCbl, inhibited L. monocytogenes. • Four B 12 analogues inhibited L. delbrueckii at concentrations 50 times that of B 12. • B 12 analogues might act on L. delbrueckii through competitive inhibition. • B 12 analogue inhibitory action is species-based, necessitating specific-validation. [ABSTRACT FROM AUTHOR]

CONTEXT: Trabeculectomy is the most common surgical procedure for treatment of glaucoma. To improve success rates, adjuvants were utilized as Mitomycin C (MMC) and Ologen implant. AIMS: This study aims to establish efficacy and safety of Ologen implant versus MMC in trabeculectomy. SETTING AND DESIGN: A prospective, comparative clinical study was conducted at the Department of Ophthalmology, Assiut University, between December 2014 and April 2016. SUBJECTS AND METHODS: Patients with primary open-angle glaucoma (OAG), primary narrow-angle glaucoma and secondary OAG were assigned equally to trabeculectomy with Ologen, 0.4 mg/mL or 0.2 mg/mL MMC. The study outcome measures were reduction in intra-ocular pressure (IOP), success rates, survival analysis, and rate of complications. STATISTICAL ANALYSIS USED: SPSS software Version 17.0 (SPSS, Inc., IL, USA) was utilized. RESULTS: Thirty eyes were included in the study. Mean baseline IOP in Ologen, MMC 0.4 and MMC 0.2 groups were 27.43 ± 2.97, 28.4 ± 3.24, and 27.56 ± 2.69 mmHg, respectively. At week 24 follow-up, mean IOP in Ologen, MMC 0.4 and MMC 0.2 groups were 18.55 ± 3.18, 16.2 ± 3.22, and 16.93 ± 3.04 mmHg, respectively. No significant inter-group difference was noticed at any visits. Complete success was achieved in 10%, 40%, and 30%, whereas incomplete success in 70%, 50%, and 60%, respectively in Ologen, MMC 0.4 and MMC 0.2 groups. No treatment group difference was reported by Kaplan–Meier analysis. Shallow anterior chamber occurred more in Ologen and MMC 0.4 groups. A single case of serous choroidal effusion had occurred in MMC 0.4 group. CONCLUSION: Ologen implant is a promising alternative to MMC for improving the success rate of trabeculectomy.

The rise in antibiotic resistance among bacterial pathogens has prompted the exploitation of alternative antibacterial strategies, such as antivirulence therapy. By inhibiting virulence traits, antivirulence drugs are expected to lessen pathogenicity without affecting bacterial growth, therefore avoiding the spread of resistance. However, some studies argued against this assumption, and the lack of antivirulence drugs in clinical use hampers the empirical assessment of this concept. Here we compared the mode of action and range of activity of two drugs which have been proposed for repurposing as quorum sensing and pyoverdine inhibitors in the human pathogen Pseudomonas aeruginosa: the anticancer drug 5-fluorouracil (5-FU) and the antimycotic drug 5-fluorocytosine (5-FC), respectively. The effect on bacterial growth, emergence and spread of resistance, and activity against clinical isolates were assessed. Our results confirm that 5-FU has growth inhibitory activity on reference strains and can rapidly select for spontaneous resistant mutants with loss-of-function mutations in the upp gene, responsible for uracil conversion into UMP. These mutants were also insensitive to the anti-pyoverdine effect of 5-FC. Conversely, 5-FC did not cause relevant growth inhibition, likely because of poor enzymatic conversion into 5-FU by cytosine deaminase. However, coculturing experiments showed that 5-FU resistant mutants can outcompete sensitive cells in mixed populations, in the presence of not only 5-FU but also 5-FC. Moreover, we observed that serial passages of wild-type cells in 5-FC-containing medium leads to the appearance and spread of 5-FC insensitive sub-populations of 5-FU resistant cells. The different effect on growth of 5-FU and 5-FC was overall conserved in a large collection of cystic fibrosis (CF) isolates, corresponding to different infection stages and antibiotic resistance profiles, although high variability was observed among strains. Notably, this analysis also revealed a significant number of pyoverdine-deficient isolates, whose proportion apparently increases over the course of the CF infection. This study demonstrates that the efficacy of an antivirulence drug with no apparent effect on growth can be significantly influenced by the emergence of insensitive mutants, and highlights the importance of the assessment of resistance-associated fitness cost and activity on clinical isolates for the development of “resistance-proof” antivirulence drugs.

The rise in antibiotic resistance among bacterial pathogens has prompted the exploitation of alternative antibacterial strategies, such as antivirulence therapy. By inhibiting virulence traits, antivirulence drugs are expected to lessen pathogenicity without affecting bacterial growth, therefore avoiding the spread of resistance. However, some studies argued against this assumption, and the lack of antivirulence drugs in clinical use hampers the empirical assessment of this concept. Here we compared the mode of action and range of activity of two drugs which have been proposed for repurposing as quorum sensing and pyoverdine inhibitors in the human pathogen Pseudomonas aeruginosa : the anticancer drug 5-fluorouracil (5-FU) and the antimycotic drug 5-fluorocytosine (5-FC), respectively. The effect on bacterial growth, emergence and spread of resistance, and activity against clinical isolates were assessed. Our results confirm that 5-FU has growth inhibitory activity on reference strains and can rapidly select for spontaneous resistant mutants with loss-of-function mutations in the upp gene, responsible for uracil conversion into UMP. These mutants were also insensitive to the anti-pyoverdine effect of 5-FC. Conversely, 5-FC did not cause relevant growth inhibition, likely because of poor enzymatic conversion into 5-FU by cytosine deaminase. However, coculturing experiments showed that 5-FU resistant mutants can outcompete sensitive cells in mixed populations, in the presence of not only 5-FU but also 5-FC. Moreover, we observed that serial passages of wild-type cells in 5-FC-containing medium leads to the appearance and spread of 5-FC insensitive sub-populations of 5-FU resistant cells. The different effect on growth of 5-FU and 5-FC was overall conserved in a large collection of cystic fibrosis (CF) isolates, corresponding to different infection stages and antibiotic resistance profiles, although high variability was observed among strains. Notably, this analysis also revealed a significant number of pyoverdine-deficient isolates, whose proportion apparently increases over the course of the CF infection. This study demonstrates that the efficacy of an antivirulence drug with no apparent effect on growth can be significantly influenced by the emergence of insensitive mutants, and highlights the importance of the assessment of resistance-associated fitness cost and activity on clinical isolates for the development of "resistance-proof" antivirulence drugs. [ABSTRACT FROM AUTHOR]

Résumé Le succès d'une greffe repose sur une gestion optimale des médicaments immunosuppresseurs, que ce soit lors de leur prescription, de leur délivrance ou de leur administration. Le pharmacien est un maillon déterminant dans le suivi du traitement d'entretien. Il prodigue des conseils adaptés au patient transplanté, s'assure de la bonne observance thérapeutique et évalue les éventuels effets iatrogènes. Summary The success of a transplant depends on an optimal management of immunosuppressants, when they are prescribed, dispensed and administered. Pharmacists play a key role in monitoring the maintenance therapy. They provide advice adapted to the transplant recipient, ensure proper compliance with medication and assess any iatrogenic effects. [ABSTRACT FROM AUTHOR]

Abstract Malonyl-CoA is a central metabolite in fatty acid biochemistry. It is the rate-determining intermediate in fatty acid synthesis but is also an allosteric inhibitor of the rate-setting step in mitochondrial long-chain fatty acid oxidation. While these canonical cytoplasmic roles of malonyl-CoA have been well described, malonyl-CoA can also be generated within the mitochondrial matrix by an alternative pathway: the ATP-dependent ligation of malonate to Coenzyme A by the malonyl-CoA synthetase ACSF3. Malonate, a competitive inhibitor of succinate dehydrogenase of the TCA cycle, is a potent inhibitor of mitochondrial respiration. A major role for ACSF3 is to provide a metabolic pathway for the clearance of malonate by the generation of malonyl-CoA, which can then be decarboxylated to acetyl-CoA by malonyl-CoA decarboxylase. Additionally, ACSF3-derived malonyl-CoA can be used to malonylate lysine residues on proteins within the matrix of mitochondria, possibly adding another regulatory layer to post-translational control of mitochondrial metabolism. The discovery of ACSF3-mediated generation of malonyl-CoA defines a new mitochondrial metabolic pathway and raises new questions about how the metabolic fates of this multifunctional metabolite intersect with mitochondrial metabolism. [ABSTRACT FROM AUTHOR]

Pharmacokinetic enhancers (boosters) are compounds used in combination with a primary therapeutic agent (drug) and are not used for their direct effects on the disease but because they enhance or restore the activity of the primary agent. Hence, in certain cases, they represent an indispensable escort for enzyme-labile drugs. Pharmacokinetic enhancers can exert their activity on different ways. In the most common case, they inhibit enzymes such as human cytochrome P450 enzymes in the liver or other organs and, thereby, block or reduce undesired metabolism and inactivation of the primary drug. In this review, an overview will be given on the therapeutically most important classes of pharmacokinetic enhancers like β-lactamase inhibitors, inhibitors of CYP (cytochrome P450) enzymes in HIV therapy and hepatitis C, boosters for fluoropyrimidine-type anticancer agents, compounds utilized for enabling therapy of Parkinson's disease with levodopa, and others. Inhibitors of efflux pumps in both pathogenic bacteria and tumor cells will be addresses shortly. [ABSTRACT FROM AUTHOR]

Background: Cladribine is an antimetabolite used for the treatment of relapsing–remitting multiple sclerosis. At present, there are no data available on its use in breastfeeding mothers and its transfer in human milk. Objective: We present a case of a lactating mother who donated her milk samples to study the transfer of cladribine following a 20-mg oral dose. Methods: Analysis was done using liquid chromatography–mass spectrometry. Results: The relative infant dose calculated in this study was 3.06%. Conclusion: This is the first case report suggesting the transfer of cladribine in human milk in measurable quantities. However, caution should be advised during lactation. [ABSTRACT FROM AUTHOR]

Viral infection treatment is a difficult task due to its complex structure and metabolism. Additionally, viruses can alter the metabolism of host cells, mutate, and readily adjust to harsh environments. Coronavirus stimulates glycolysis, weakens mitochondrial activity, and impairs infected cells. In this study, we investigated the efficacy of 2-DG in inhibiting coronavirus-induced metabolic processes and antiviral host defense systems, which have not been explored so far. 2-Deoxy- d -glucose (2-DG), a molecule restricting substrate availability, has recently gained attention as a potential antiviral drug. The results revealed that 229E human coronavirus promoted glycolysis, producing a significant increase in the concentration of fluorescent 2-NBDG, a glucose analog, particularly in the infected host cells. The addition of 2-DG decreased its viral replication and suppressed infection-induced cell death and cytopathic effects, thereby improving the antiviral host defense response. It was also observed that administration of low doses of 2-DG inhibited glucose uptake, indicating that 2-DG consumption in virus-infected host cells was mediated by high-affinity glucose transporters, whose levels were amplified upon coronavirus infection. Our findings indicated that 2-DG could be a potential drug to improve the host defense system in coronavirus-infected cells. [Display omitted] [ABSTRACT FROM AUTHOR]