Purine Research Articles

TMET-14. ENOLASE 2 IS A UNIQUE METABOLIC VULNERABILITY INDUCED BY THE 1P19Q CODELETION IN OLIGODENDROGLIOMAS

Abstract Gliomas are devastating primary brain tumors in adults. The presence of an isocitrate dehydrogenase mutation combined with a chromosomal 1p/19q codeletion discriminates oligodendrogliomas from astrocytomas. The goal of this study was to leverage metabolic vulnerabilities induced by the 1p/19q codeletion for oligodendroglioma therapy. The 1p19q codeletion results in loss of enolase 1 (ENO1), which converts 2-phosphoglycerate to phosphoenolpyruvate during glycolysis. Here, we show that enolase 2 (ENO2) is upregulated in patient-derived oligodendroglioma (SF10417, BT88, BT54) models relative to astrocytoma (BT142, SF10602) and normal human astrocytes. ENO2 is also elevated in oligodendroglioma patient biopsies relative to astrocytoma or gliosis. Mechanistic studies indicate that inhibiting MEK1 or ERK1 abrogates ENO2 expression, suggesting that the MAPK pathway upregulates ENO2 in oligodendrogliomas. Next, we examined the therapeutic potential of targeting ENO2 in oligodendrogliomas. Genetic ablation of ENO2 or pharmacological inhibition using POMHEX inhibited the viability of SF10417 and BT88 cells with IC50 values of ~50 nM. In contrast, the IC50 for BT142 and SF10602 astrocytoma cells was ~5-8 uM, highlighting the exquisite dependence of oligodendrogliomas on ENO2. However, ENO2 inhibition did not lead to cytotoxicity in patient-derived oligodendroglioma cells or intracranial tumor xenografts. To assess the metabolic consequences of ENO2 inhibition and identify potential compensatory alterations, we traced [U-13C]-glucose metabolism in vivo in mice bearing intracranial SF10417 tumors. Although POMHEX abrogated glycolytic metabolism downstream of 2-phosphoglycerate, it shunted glucose towards biosynthesis of serine, glycine, methionine and purine nucleotides, an effect that was driven by phosphoglycerate dehydrogenase (PHGDH), the rate-limiting enzyme for serine biosynthesis. Importantly, the novel PHGDH inhibitor PHGDH-D8 was synthetically lethal in combination with POMHEX in oligodendroglioma cells and the combination induced apoptosis in mice bearing intracranial SF10417 tumors. Collectively, we exploit a mechanistic understanding of metabolic vulnerabilities induced by the 1p19q codeletion to identify combined inhibition of ENO2 and PHGDH as a novel therapeutic opportunity for oligodendrogliomas.

Novel Dipeptide Inhibitors of PfPNP: In-Silico Identification of Promising New Antimalarials.

Malaria, an infectious disease caused by Plasmodium falciparum, is becoming increasingly difficult to treat due to the emergence of drug-resistant strains. Recent studies have proposed purine nucleoside phosphorylase from P. falciparum (PfPNP) as a potential target for malaria treatment. In the present study, we designed a virtual library of 400 dipeptides to discover novel anti-malarial peptide inhibitors. A structure-based molecular docking method was employed to virtually screen the designed library against the wild-type structure of PfPNP (PDB: 5ZNC). The best four (Phe-Arg, Arg-His, Trp-Arg and Tyr-Arg) dipeptides, which were then investigated for their binding potential against PfPNP using Molecular Dynamics simulation studies. Parameters such as RMSD, RMSF, Rg, and SASA were analyzed to understand the structural changes, energetics, and overall behavior of PfPNP-dipeptide complexes. The PfPNP demonstrated significant stability upon binding with each of the identified dipeptides with ΔG of over -168 kcal/mol. Additionally, DFT and ADME predictions indicated that the electronic structure, energetics, and pharmacokinetic properties of Phe-Arg, Arg-His, Trp-Arg and Tyr-Arg were favourable for drug development. Our comprehensive computational investigation has identified these four dipeptides as promising candidates. These designed and selected dipeptides may further be modified using peptidomimetic and medicinal chemistry tools to develop a novel class of promising antimalarials.

Host-derived Lactobacillus plantarum alleviates hyperuricemia by improving gut microbial community and hydrolase-mediated degradation of purine nucleosides.

The gut microbiota is implicated in the pathogenesis of hyperuricemia (HUA) and gout. However, it remains unclear whether probiotics residing in the host gut, such as Lactobacillus, can prevent HUA development. Herein, we isolated Lactobacillus plantarum SQ001 from the cecum of HUA geese and conducted in vitro assays on uric acid (UA) and nucleoside co-culture. Metabolomics and genome-wide analyses, revealed that this strain may promote nucleoside uptake and hydrolysis through its nucleoside hydrolase gene. The functional role of iunH gene was confirmed via heterologous expression and gene knockout studies. Oral administration of L. plantarum SQ001 resulted in increased abundance of Lactobacillus species and reduced serum UA levels. Furthermore, it downregulated hepatic xanthine oxidase, a key enzyme involved in UA synthesis, as well as renal reabsorption protein GLUT9, while enhancing the expression of renal excretion protein ABCG2. Our findings suggest that L. plantarum has potential to ameliorate gut microbial dysbiosis with HUA, thereby offering insights into its potential application as a probiotic therapy for individuals with HUA or gout.

Outgrowth of Escherichia is susceptible to aggravation of systemic lupus erythematosus

BackgroundSystemic lupus erythematosus (SLE) is linked to host gut dysbiosis. Here we performed faecal gut microbiome sequencing to investigate SLE-pathogenic gut microbes and their potential mechanisms.MethodsThere were 134 healthy controls (HCs) and 114 SLE cases for 16 S ribosomal RNA (rRNA) sequencing and 97 HCs and 124 SLE cases for shotgun metagenomics. Faecal microbial changes and associations with clinical phenotypes were evaluated, and SLE-associated microbial genera were identified in amplicon analysis. Next, metagenomic sequencing was applied for accurate identification of microbial species and discovery of their metabolic pathways and immunogenic peptides both relevant to SLE. Finally, contribution of specific taxa to disease development was confirmed by oral gavage into lupus-prone MRL/lpr mice.ResultsSLE patients had gut microbiota richness reduction and composition alteration, particularly lupus nephritis and active patients. Proteobacteria/Bacteroidetes (P/B) ratio was remarkably up-regulated, and Escherichia was identified as the dominantly expanded genus in SLE, followed by metagenomics accurately located Escherichia coli and Escherichia unclassified species. Significant associations primarily appeared among Escherichia coli, metabolic pathways of purine nucleotide salvage or peptidoglycan maturation and SLE disease activity index (SLEDAI), and between multiple epitopes from Escherichia coli and disease activity or renal involvement phenotype. Finally, gavage with faecal Escherichia revealed that it upregulated lupus-associated serum traits and aggravated glomerular lesions in MRL/lpr mice.ConclusionWe characterize a novel SLE exacerbating Escherichia outgrowth and suggest its contribution to SLE procession may be partially associated with metabolite changes and cross-reactivity of gut microbiota-associated epitopes and host autoantigens. The findings could provide a deeper insight into gut Escherichia in the procession of SLE.

The effectiveness of a synthetic analogue purine nucleoside bases in the treatment of acute respiratory viral infections

Introduction. The aggravation of the comorbid background of patients with ARVI is the main reason for the addition of secondary pathogenic and conditionally pathogenic bacterial flora and, as a result, the development of local and general complications.Аim. To conduct a clinical assessment of the efficacy and safety of the drug Triazavirin based on riamilovir in the treatment of acute respiratory viral infections.Materials and methods. The study conducted on the basis of the medical center of the Federal State Budgetary Educational Institution of the Russian Ministry of Health involved 56 patients with acute recurrent viral infection. Regarding the prescribed therapy, the patients were divided into 2 groups: group 1 (n = 27) from day 2, triazavirin was taken as an antiviral drug (riamilo- vir) 250 mg (1 capsule) 3 times a day for 5 days; group 2 (n = 29) – as an antiviral drug, Kagocel took 2 tablets 3 times a day for 2 days, then 1 tablet 3 times a day for 5 days. The effect of the therapy was assessed by the severity of intoxication syndrome, rhinorrhea, difficulty in nasal breathing, decreased olfactory function, pain syndrome localized in the nasopharynx and throat, cough severity and laboratory results.Results. In patients with 7 days of therapy, the indicator of psychological health increased by 34.7 points in the first group, by 28.8 points in the second group. Vital activity increased by 33.7 points in patients of group 1 and by 23.8 points in the second group. Physical activity tended to increase by 19.5 points and 6.0 points in the first and second groups, respectively.Conclusions. The analysis of changes in the severity of clinical symptoms affecting the quality of life of patients confirmed the effectiveness and safety of the drug Triazavirin.

Growth Performance and Microbial Activity Positively Responded to Interactive Effect of Nitrogen and Phosphorus in Young Holstein Dairy Calves.

We hypothesized that nitrogen (N) and phosphorus (P), as two pivotal nutrients that contributed to the growth of growing animals, may have interactive effect on growth performance and microbial development in young calves. For this purpose, feeding two starter protein contents (20% [20CP] vs. 24% [24CP], DM basis) and two phosphorus supplementation levels (0.35% [0.35P] and 0.70% [0.7P], DM basis) was evaluated on growth performance, health indicators, digestibility of nutrients and microbial protein synthesis (MPS), the latter estimated from urinary purine derivatives (PDs). Forty-eight female Holstein calves (3 days of age) were assigned randomly to the following treatments: 20CP-0.35P, 20CP-0.7P, 24CP-0.35P and 24CP-0.7P (n = 12, each). Milk feeding schedule was identical among treatments until weaning (d 59), but study lasted until d 73. Feeding 24CP compared to 20CP diet tended to improve starter intake, increased average daily gain (ADG) during pre-weaning period (p < 0.05), and final body weight (p = 0.01). Higher P supplementation has marginal effect on starter intake but improved ADG (pre-weaning; p = 0.02) and microbial activity by greater MPS (p = 0.02) compared to 0.35P. The greatest starter intake, the most favourable general appearance score, the highest withers height, the highest hip height, the greatest organic matter and neutral detergent digestibility, and the greatest MPS were found when calves fed diets contained 24CP along with 0.7P in starter. Based on the current study results, N and P have separate effects on the growth performance of young calves; however, their positive interaction can be attributable to growth performance and microbial development, especially during the pre-weaning period.

Determination of 42 antimicrobials in disinfection products by dispersive solid phase extraction-high performance liquid chromatography-tandem mass spectrometry

Antimicrobials inhibit the growth and reproduction of microorganisms thereby alleviating skin and other problems caused by microorganisms. Antimicrobials are classified into different categories, including antibacterials, antifungals, and antivirals, among others, and include azoles, sulfonamides, tetracyclines, quinolones, and many other classes of synthetic and natural compound. The inappropriate or excessive use of antimicrobials can damage skin and other human organs and increase antimicrobial resistance. Relevant regulations and standards clearly state that antimicrobials are prohibited for use as ingredients in disinfection products. However, since antimicrobials enhance the disinfection or antibacterial effect of a product, with a significant short-term effect, antimicrobials are occasionally illegally added to disinfectant products, including those intended for human use. Therefore, establishing testing methods that provide technical support for enforcing regulations is an urgent objective. Herein, a method was established for the analysis of 42 antimicrobials in disinfection products, that is applicable to common types of disinfection-product matrix, including creams, gels, and aqueous solutions, using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) combined with dispersive solid phase extraction. The 42 antimicrobials comprise antibacterials, antifungals, and antivirals, and include seven sulfonamides, ten quinolones, three lincosamides, five tetracyclines, three macrolides, eight azoles, three purine nucleoside analogs, one furan, one nonpolyene antifungal, and one steroid. Briefly, 0.2 g of a sample was first dispersed in 2 mL of water and then extracted with 10 mL of 0.5% formic acid in acetonitrile, with 3 g of anhydrous Na2SO4 added to remove water. After centrifugation, 5 mL of the supernatant was cleaned using dispersive solid phase extraction with EMR-Lipid as the adsorbent. Lipids, waxes, surfactants, and moisturizing lubricants are commonly used as cream and gel matrices. Matrix substances containing long carbon chains dissolved in acetonitrile were removed using the EMR-Lipid adsorbent. Target analytes were separated on a Poroshell 120 EC-C18 analytical chromatography column (150 mm×3.0 mm, 2.7 μm), with 0.1% formic acid in acetonitrile and 0.1% formic acid aqueous solution used as mobile phases under gradient-elution conditions. The target analytes in the test solution were detected in positive ionization (ESI+) and multi-reaction-monitoring (MRM) modes. Analytes were characterized in terms of their retention times and selected ions, and quantified using the external-standard method. The main factors affecting method response, recovery, and sensitivity, such as the extraction method and solvent, purification method and adsorbent, mobile phase, and MS conditions, were examined during sample pretreatment and instrumental analysis. The 42 antimicrobials were effectively separated under the optimized experimental conditions; the target compounds exhibited linear working curves in the 0.25-5.0 mg/kg concentration range, with correlation coefficients (r) greater than 0.99. Limits of detection (LODs) for the 42 antimicrobials were determined from the signal-to-noise ratios (S/N) of their chromatographic peaks. LODs of 0.03-0.10 mg/kg were determined for the three matrices using 0.2-g samples and 10-mL test solution. Recoveries of 80.3-109.8%, with relative standard deviations (RSDs) of less than 9.8%, were obtained by determining three levels of each target analyte added to the three blank matrices; this process was repeated for six parallel samples. The developed method was used to analyze antimicrobials in commercially available disinfection products, with two sample batches testing positive. The established method is simple, accurate, precise, and suitable for the rapid screening and quantification of antimicrobials in disinfection products. This study provides powerful technical support for regulating the illegal addition of related antimicrobials to disinfection products.

PGE2 Binding Affinity of Hemocyte Membrane Preparations of Manduca sexta and Identification of the Receptor-Associated G Proteins in Two Lepidopteran Species.

Prostaglandin E2 (PGE2) is an eicosanoid that mediates a range of physiological actions in vertebrates and invertebrates, including reproduction and immunity. The PGE2 receptor was identified and functionally assessed in two lepidopteran insects, Manduca sexta and Spodoptera exigua. However, its binding affinity to the receptor has not been reported. The PGE2 receptor is a G-protein coupled receptor (GPCR) although its corresponding G-protein is not identified. PGE2 binding assays were performed with membrane preparations from hemocytes of M. sexta larvae. We recorded an optimal binding in 4 h reactions conducted at pH 7.5 with 12 nM tritium-labeled PGE2. We found that hemocytes express a single population of PGE2 binding sites with a high affinity (Kd = 35 pmol/mg protein), which are specific and saturable. The outcomes of experiments on the influence of purine nucleotides suggested these are functional GPCRs. A bioinformatics analysis led to a proposed trimeric G-protein in the S. exigua transcriptome, in which the Gα subunit is classified into five different types: Gα(o), Gα(q), Gα(s), Gα(12), and Gα(f). After confirming expressions of these five types in S. exigua, individual RNA interference (RNAi) treatments were applied to the larvae using gene-specific double-stranded RNAs. RNAi treatments specific to Gα(s) or Gα(12) gene expression significantly suppressed the cellular immune responses although the RNAi treatments specific to other three Gα components did not. While PGE2 treatments led to elevated hemocyte cAMP or Ca2+ levels, the RNAi treatments specific to Gα(s) or Gα(12) genes led to significantly reduced second messenger levels under PGE2, although the RNAi treatments specific to the other three Gα components did not. These results showed that the PGE2 receptor has high PGE2 affinity in the nanomolar range and binds G-proteins containing a Gα(s) or Gα(12) trimeric component in S. exigua and M. sexta, and likely, all lepidopteran insects.

Effect of High-Tannin and -Polyphenol Plant Material Supplement on Rumen Fermentation, Nitrogen Partitioning and Nutrient Utilization in Beef Cattle

The current issue of ruminant methane emissions is still being researched by animal nutritionists in an effort to find new approaches. In this study, five beef cattle were randomly assigned in a 5 × 5 Latin square design to examine the effects of supplementation with high-tannin and -polyphenol plant materials on nutrient utilization, rumen fermentation, and nitrogen partitioning. Cattle offered total mixed ration (TMR) silage diets with or without tannin-rich tree leaf or plant herbs, such as Piper sarmentosum Roxb., Cymbopogon citratus (DC.) Stapf, Anacardium occidentale L., and Careya arborea Roxb., were supplemented at a dose of 10 g/d. Prior to TMR feeding, the animals’ meals were supplemented with 10 g of fortified plant materials twice a day, along with 100 g of rice bran. The animals in the control group received only 100 g of rice bran and no other plant materials. The result showed that there was no difference in nutrient intake or digestibility between the supplemented and control groups. Although the effect of ruminal pH, NH3-N, Total VFA, acetate (C2), and butyrate (C4) was not significant (p &gt; 0.05), the proportion of propionate (C3) tended to increase with supplementation (p = 0.07). There was no difference in the excretion of purine derivatives or the amount of microbial nitrogen supply, even though supplemented animals had significantly lower protozoal populations than the control group (p &lt; 0.05). Moreover, when A. occidentale or C. arborea was added to the TMR silage diet, the nitrogen intake and retention increased considerably, although total nitrogen excretion decreased. In this approach, the leaves of Anacardium occidentale L. and Careya arborea Roxb. were particularly promising for strategic supplementation.

Determination of non-cytotoxic antiviral concentrations of purine and indole derivatives in vitro

Mammalian cells from lines derived from bovine embryonic trachea (EBTr) were used in the present study. After the formation of semi-confluent monolayers, one subpopulation of cells was inoculated with the vaccine avian poxvirus strain FK (fowl) and the other with the vaccine avian poxvirus strain Dessau (pigeon) (Poxviridae family). Twenty-four hours after viral inoculation, individual subsets of infected cells were treated with the purine derivative aminophylline and the remaining subsets with the indole derivative ergotamine tartrate, respectively. The effects of the analogues thus administered on the cells were recorded at the 24th hour and 48th hour after treatment with each substance, respectively. In cells inoculated with the FK viral strain and treated with both aminophylline and ergotamine tartrate, decreased cell viability was observed at all dilutions at the 48th hour post-treatment compared to the 24th hour. In aminophylline-treated cells, these differences were not statistically significant, unlike in ergotamine tartrate-treated cells, where they were statistically significant. In the same cells infected with the Dessau strain and treated with aminophylline, although decreased cell viability was found at the 48th hour of treatment compared to the 24th hour, in most cases no statistically significant differences were found. In cells infected with the same strain but treated with ergotamine tartrate, despite the lack of statistically significant differences, increased cell viability was seen at the 48th hour post-treatment compared to the 24th hour, specifically at the higher concentrations of 10-3 and 10-4 M/mL. These results suggest a lower cytotoxicity of aminophylline compared to ergotamine tartrate, but on the other hand, a higher anti-viral activity of ergotamine tartrate against the Dessau virus strain compared to aminophylline in in vitro conditions. Further studies need to be conducted in this regard.

CRISPR/Cas9 editing of two adenine phosphoribosyl transferase coding genes reveals the functional specialization of adenine salvage proteins in common bean.

Adenine metabolism is important for common bean (Phaseolus vulgaris L) productivity since this legume uses ureides derived from the oxidation of purine nucleotides, as their primary nitrogen storage molecules. Purine nucleotides are produced from de novo synthesis or through salvage pathways. Adenine phosphoribosyl transferase (APRT) is the enzyme dedicated to adenine nucleobase salvage for nucleotide synthesis, but it also acts on the inactivation of cytokinin bases. In common bean, the APRT enzyme is encoded by four genes. Gene expression analysis, biochemical properties and subcellular location suggest functional differences among the common bean APRT isoforms. CRISPR/Cas9 targeted downregulation of two of the four PvAPRTs followed by metabolomics and physiological analyses of targeted hairy roots reveals that, although the two proteins have redundant functions, PvAPRT1 mostly participates in the salvage of adenine, whereas PvAPRT5 is the predominant form in the regulation of cytokinin homeostasis and stress responses with a high impact in root and nodule growth.

Quantum computational and experimental spectroscopic investigation (FT-IR, Raman, UV–Vis), PES, LHE and topological investigations of 7-[(2R)-2-hydroxypropyl]-1,3-dimethylpurine-2,6-dione

The current research explored the structural optimization, electrical and vibrational characteristics, and quantum chemical calculations via the procedure of DFT for a purine derivative, 7-[(2R)-2-hydroxypropyl]-1,3-dimethylpurine-2,6-dione (2HDPD). Functional groups were found by correlating FT-IR with simulated spectra. TD-DFT calculations were done for UV–vis absorption and to ascertain the electronic properties of both the solvent and the gas phase, enabling additional study of the compounds LHE. The experimental outcomes and theoretic parameters are in good agreement. LUMO and HOMO band gaps spectacle that the molecule is chemically reactive and that there is adequate charge transfer. Polar solvent exhibits the highest band gap value, 5.057 eV. Numerous topological considerations were accomplished using the Multiwfn tool. Charge transfer investigations have demonstrated the most imperative states. Weak intermolecular interactions were investigated using RDG analysis, LOL, NBO, and ELF. The 2HDPD compounds reactive areas were discovered by applying the MEP and Fukui investigations. Hyperpolarizability characteristics were used to calculate NLO behavior. The drug-like characteristics of the molecule follow Lipinski five rules. After docking with the proteins 1NG2, 2DVV, 3CAF, and 7OEX, the compound 2HDPD showed moderate binding affinities of −5.28, −5.04, −4.96, and −5.66 kcal/mol, in that order. The Ramachandran plot verified the proteins stability and advantageous locations. The Docking results show compound 2HDPD exhibited a COPD property.

Substrate preference, RNA binding and active site versatility of Stenotrophomonas maltophilia nuclease SmNuc1, explained by a structural study.

Nucleases of the S1/P1 family have important applications in biotechnology and molecular biology. We have performed structural analyses of SmNuc1 nuclease from Stenotrophomonas maltophilia, including RNA cleavage product binding and mutagenesis in a newly discovered flexible Arg74-motif, involved in substrate binding and product release and likely contributing to the high catalytic rate. The Arg74Gln mutation shifts substrate preference towards RNA. Purine nucleotide binding differs compared to pyrimidines, confirming the plasticity of the active site. The enzyme-product interactions indicate a gradual, stepwise product release. The activity of SmNuc1 towards c-di-GMP in crystal resulted in a distinguished complex with the emerging product 5'-GMP. This enzyme from an opportunistic pathogen relies on specific architecture enabling high performance under broad conditions, attractive for biotechnologies.

Purines and purinergic receptors in primary tumors of the central nervous system.

Purine nucleotides and nucleosides play critical roles in various pathological conditions, including tumor cell growth. Adenosine triphosphate (ATP) activates pro-tumor receptors, while adenosine (ADO) is a potent immunosuppressant and modulator of cell growth. This study aims to analyze the purinergic actions of ATP and its metabolites, associated enzymes, and P1 or P2 class receptors in primary central nervous system tumors. Additionally, we sought to correlate the levels of nucleosides and the density of P1, P2X, and P2Y receptors in cells with tumor progression. The results indicate that purinergic signaling depends on the receptor concentration and signaling molecules specific to each cell type, tissue, and tumor histology. The purinergic system may function as either a tumor-promoting agent or an antitumor factor, depending on the microenvironmental conditions and the concentrations of receptors and their respective activators. Notably, ATP emerges as the most significant extracellular signal, capable of being converted into other cellular stimulators pertinent to neoplasms, such as adenosine diphosphate, adenosine monophosphate, adenosine, and inosine. Consequently, a cascade of responses to these stimuli promotes tumor development, cell division, and metastasis. Purine nucleotides in central nervous system tumors are pivotal in cellular responses in glioblastoma multiforme, vestibular schwannoma, medulloblastoma, adenomas, gliomas, meningiomas, and pineal tumors. These findings hold the potential for developing novel therapeutic strategies and aiding in therapeutic management.

Interaction of Purine and its Derivatives with A1, A2-Adenosine Receptors and Vascular Endothelial Growth Factor Receptor-1 (Vegf-R1) as a Therapeutic Alternative to Treat Cancer.

There are several studies that indicate that cancer development may be conditioned by the activation of some biological systems that involve the interaction of different biomolecules, such as adenosine and vascular endothelial growth factor. These biomolecules have been targeted of some drugs for treat of cancer; however, there is little information on the interaction of purine derivatives with adenosine and vascular endothelial growth factor receptor (VEGF-R1). The aim of this research was to determine the possible interaction of purine (1: ) and their derivatives (2-31: ) with A1, A2-adenosine receptors, and VEGF-R1. Theoretical interaction of purine and their derivatives with A1, A2-adenosine receptors and VEGF-R1 was carried out using the 5uen, 5mzj and 3hng proteins as theoretical tools. Besides, adenosine, cgs-15943, rolofylline, cvt-124, wrc-0571, luf-5834, cvt-6883, AZD-4635, cabozantinib, pazopanib, regorafenib, and sorafenib drugs were used as controls. The results showed differences in the number of aminoacid residues involved in the interaction of purine and their derivatives with 5uen, 5mzj and 3hng proteins compared with the controls. Besides, the inhibition constants (Ki) values for purine and their derivatives 5: , 9: , 10: , 14: , 15: , 16: , and 20: were lower compared with the controls CONCLUSIONS: Theoretical data suggest that purine and their derivatives 5: , 9: , 10: , 14: , 15: , 16: , and 20: could produce changes in cancer cell growth through inhibition of A1, A2-adenosine receptors and VEGFR-1 inhibition. These data indicate that these purine derivatives could be a therapeutic alternative to treat some types of cancer.

Relationship between pyrimidines, purines and fatty acids in milk of dairy cows fed distinct carbohydrate types: a metabolomic approach

The aim of this research was to evaluate changes in the milk metabolome of dairy cows fed different carbohydrate types from silages and concentrates, with special focus on purines and pyrimidines, likely associated with the microbial activity in the rumen. Furthermore, the relationship between the milk fatty acids and pyrimidine and purine metabolism retrieved in milk was investigated for potential correlations between these 2 groups of potential milk biomarkers. Twenty-four lactating dairy cows were used in a crossover design, where each cow received 2 of 4 diets. Diets were formulated based on a 2 by 2 factorial arrangement, using either grass-clover or corn silage as a forage source, and barley or dried beet pulp in the concentrate fraction. Fatty acids and LC-MS metabolome of the milk were analyzed. The milk metabolome and fatty acid concentration could differentiate the 4 diets used in the trial, while the milk metabolome alone could only differentiate the 2 silage types. Milk odd-chain fatty acids (C17:1 and C17:0) were correlated with pyrimidine and purine derivatives, with uric acid being significantly higher in milk samples associated with corn silage diets. Therefore, the results indicate potential differences in microbial protein synthesis between the diets, but a validation with actual ruminal microbial protein synthesis and investigation in digestive biofluids are necessary for further confirmation.

Evolution of the biochemistry underpinning purine alkaloid metabolism in plants.

Purine alkaloids are naturally occurring nitrogenous methylated derivatives of purine nucleotide degradation products, having essential roles in medicine, food and various other aspects of our daily lives. They are generated through convergent evolution in different plant species. The pivotal reaction steps within the purine alkaloid metabolic pathways have been largely elucidated, and the convergent evolution of purine alkaloids has been substantiated through bioinformatic, biochemical and other research perspectives within S-adenosyl-ʟ-methionine-dependent N-methyltransferases. Currently, the biological and ecological roles of purine alkaloids, further refinement of the purine alkaloid metabolic pathways and the investigation of purine alkaloid adaptive evolutionary mechanisms continue to attract widespread research interest. The exploration of the purine alkaloid metabolic pathways also enhances our comprehension of the biochemical mechanism, providing insights into inter-species interactions and adaptive evolution and offering potential value in drug development and agricultural applications. Here, we review the progress of research in the distribution, metabolic pathway elucidation and regulation, evolutionary mechanism and ecological roles of purine alkaloids in plants. The opportunities and challenges involved in elucidating the biochemical basis and evolutionary mechanisms of the purine alkaloid metabolic pathways, as well as other research aspects, are also discussed. This article is part of the theme issue 'The evolution of plant meta-bolism'.

HIF-1α-HPRT1 axis promotes tumorigenesis and gefitinib resistance by enhancing purine metabolism in EGFR-mutant lung adenocarcinoma

BackgroundThe mutations of oncogenic epidermal growth factor receptor (EGFR) is an important cause of lung adenocarcinoma (LUAD) malignance. It has been knowm that metabolic reprogramming is an important hallmark of malignant tumors, and purine metabolism is a key metabolic pathway for tumor progression and drug resistance, but its relationship with the EGFR-mutant LUAD is unclear.MethodsMetabolic reprogramming was studied through capillary electrophoresis-time of flight mass spectrometry (CE-TOF/MS)-based metabolic profiling analysis. Cell proliferation in vitro was evaluated by EdU staining and cell cycle assay. Tumorigenicity in vivo was tested by subcutaneous tumor formation experiment in nude mice. The binding of hypoxia-inducible factor-1 alpha (HIF-1α) and hypoxanthine phosphoribosyltransferase 1 (HPRT1) was detected by DNA pull‑down assay and Chromatin immunoprecipitation (ChIP) assays. HIF-1α, HPRT1, DNA damage and cell apoptosis related genes were examined by western blot. In addition, RNA sequencing, mass spectrometry and bioinformatics analysis were performed.ResultsWe found that mutated EGFR (muEGFR) upregulates HPRT1 to promote purine metabolism and tumorigenesis of EGFR-mutant LUAD. Mechanistically, muEGFR increases HIF-1α expression through protein stability. Meanwhile, up-regulated HIF-1α bound to the promoter of HPRT1 and transcriptionally activates HPRT1 expression, enhancing purine metabolism to maintain rapid tumor cell proliferation in EGFR-mutant LUAD. Further, gefitinib inhibited the synthesis of purine nucleotides, and HPRT1 inhibition increased the sensitivity of gefitinib to EGFR-mutant LUAD.ConclusionsOur study reveals that muEGFR-HIF-1α-HPRT1 axis plays a key role in EGFR-mutant LUAD and provides a new strategy-inhibiting purine metabolism for treating EGFR-mutant LUAD.

Interaction of Tri-Cyclic Nucleobase Analogs with Enzymes of Purine Metabolism: Xanthine Oxidase and Purine Nucleoside Phosphorylase.

Fluorescent markers play important roles in spectroscopic and microscopic research techniques and are broadly used in basic and applied sciences. We have obtained markers with fluorescent properties, two etheno derivatives of 2-aminopurine, as follows: 1,N2-etheno-2-aminopurine (1,N2-ε2APu, I) and N2,3-etheno-2-aminopurine (N2,3-ε2APu, II). In the present paper, we investigate their interaction with two key enzymes of purine metabolism, purine nucleoside phosphorylase (PNP), and xanthine oxidase (XO), using diffraction of X-rays on protein crystals, isothermal titration calorimetry, and fluorescence spectroscopy. Crystals were obtained and structures were solved for WT PNP and D204N-PNP mutant in a complex with N2,3-ε2APu (II). In the case of WT PNP-1,N2-ε2APu (I) complex, the electron density corresponding to the ligand could not be identified in the active site. Small electron density bobbles may indicate that the ligand binds to the active site of a small number of molecules. On the basis of spectroscopic studies in solution, we found that, in contrast to PNP, 1,N2-ε2APu (I) is the ligand with better affinity to XO. Enzymatic oxidation of (I) leads to a marked increase in fluorescence near 400 nm. Hence, we have developed a new method to determine XO activity in biological material, particularly suitable for milk analysis.

Novel purine derivatives as selective CDK2 inhibitors with potential anticancer activities: Design, synthesis and biological evaluation

Purine analogues were discovered to be inhibitors of CDK2, suggesting a potential therapeutic scaffold. This paper addresses the design, synthesis, and anticancer evaluation of purine analogues as kinase inhibitors. In the early stages of the investigation, the designed compounds demonstrated a promising docking score and greater protein–ligand stability in MD simulation than the standard, indicating a higher affinity against CDK2. Thus, we synthesised new purine analogues under simple and optimised reaction conditions. Among the studies under NCI-60, 5g and 5i were the most effective, with a percentage GI of 98.09 and 90 against OVCAR-4 and SNB-75, respectively, at a dose of 10 µM. Additionally, 5g and 5i demonstrated 7.80-fold and 1.54-fold greater cytotoxicity against PA-1 and MCF-7, with IC50s of 1.08 µM and 3.54 µM, respectively, compared to seliciclib (8.43 µM and 5.46 µM). In addition, 5g and 5i showed selective cytotoxicity against PA-1 and MCF-7 than normal cells, with selectivity indexes of 26.40 and 15.45, respectively, as compared to the standard (SI=3.83 and 5.91). In the kinase selectivity assay, both compounds demonstrated greater affinity against CDK2 than other kinases, with IC50 of 0.21 µM and 0.59 µM, in contrast to the standard (IC50 = 0.63 µM). Furthermore, 5g confirmed kinase inhibition in the western blot by lowering CDK2, cyclin A2, and other downstream substrates. Moreover, it triggered cell death by apoptosis and cell cycle arrest in G2/M. Taken together, 5g merits further investigation in PKPD research to discover a potential therapeutic candidate against cancer.