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Photoemissions from aqueous solutions are prone to elastic and inelastic electron scattering, streaming potential, and space charge effect errors; however, direct assessments of their individual contributions are still a daunting challenge. Herein, to assess how these errors in a combined experimental error manner influence on the genuine photoelectron kinetic energy (PKE) spectra, the ultraviolet PKE (or electron binding energy, eBE) spectra of aqueous thymidine at different solution flow rates and laser energies were investigated by femtosecond liquid-microjet photoelectron spectroscopy. The accurate vertical eBE value of 11.33 eV for the lbi orbital of liquid water was used to calibrate the observed eBE spectra of aqueous thymidine, and the corresponding combined experimental error for the eBE of the lbi orbital of liquid water was estimated to be about 200 meV. The average combined experimental error for the vertical eBE values of the cationic ground state D0(π−1) and the cationic first excited state D1(n-−1) of aqueous thymidine was estimated to be less than 3%, i.e., in the range of several tens of meV to 200 meV, depending on different flow rates and laser energies. [ABSTRACT FROM AUTHOR]

Dual bioorthogonal labeling enables the investigation and understanding of interactions in the biological environment that are not accessible by a single label. However, applying two bioorthogonal reactions in the same environment remains challenging due to cross‐reactivity. We developed a pair of differently modified 2′‐deoxynucleosides that solved this issue for dual and orthogonal labeling of DNA. Inverse‐electron demand Diels–Alder and photoclick reactions were combined to attach two different fluorogenic labels to genomic DNA in cells. Using a small synthetic library of 1‐ and 3‐methylcyclopropenyl‐modified 2′‐deoxynucleosides, two 2′‐deoxyuridines were identified to be the fastest‐reacting ones for each of the two bioorthogonal reactions. Their orthogonal reactivity could be evidenced in vitro. Primer extension experiments were performed with both 2′‐deoxyuridines investigating their replication properties as substitutes for thymidine and evaluating subsequent labeling reactions on the DNA level. Finally, dual, orthogonal and metabolic fluorescent labeling of genomic DNA was demonstrated in HeLa cells. An experimental procedure was developed combining intracellular transport and metabolic DNA incorporation of the two 2′‐deoxyuridines with the subsequent dual bioorthogonal labeling using a fluorogenic cyanine‐styryl tetrazine and a fluorogenic pyrene‐tetrazole. These results are fundamental for advanced metabolic labeling strategies for nucleic acids in the future, especially for live cell experiments. [ABSTRACT FROM AUTHOR]

This article explores the use of dual bioorthogonal and orthogonal metabolic labeling techniques to study interactions in biological environments. The researchers developed modified 2'-desoxynucleosides to overcome the challenge of cross-reactivity and successfully linked genomic DNA in cells with two different fluorogenic markers. The study demonstrates the potential for advanced metabolic labeling strategies for nucleic acids, particularly in living cells. The authors conducted experiments to investigate the reactivity and selectivity of certain nucleosides in two different reactions, IEDDA and photoclick, for potential use in DNA labeling. While successful DNA marking was achieved using the IEDDA reaction, attempts to mark DNA using the photoclick reaction were unsuccessful. The authors also tested the nucleosides for metabolic labeling of cellular DNA, but no successful labeling was observed. Overall, this study provides a foundation for future research in metabolic labeling strategies for nucleic acids, including experiments in living cells. [Extracted from the article]

The conditioned medium (CM) obtained from mesenchymal stromal cell (MSC) culture has excellent cell growth-promoting activity and is used for cosmetics and healthcare products. Unlike pharmaceuticals, strict efficacy verification is not legally required for these products. However, their efficacy must be substantiated as commercial products. We attempted to simplify CM production and to standardize the evaluation of the growth-promoting activity of CM. CM was obtained through the culturing of two lines of commercially available human adipose tissue-derived MSCs using MEMα with or without 10% fetal bovine serum (FBS) for 24 h. Non-CM control media were produced by the same protocol without MSCs. Growth-promoting activities of the CM were estimated by [3H]-thymidine pulse. CM were subjected to molecular weight fractionation with ultrafiltration using 10 k-, 30 k-, 50 k-, and 100 k-membranes. The FBS-free CMs showed 1.34- to 1.85-fold increases and FBS-containing CMs showed 1.45- to 1.67-fold increases in proliferation-promoting activity compared with non-CM controls, regardless of the source of the cell. The thymidine incorporation levels were approximately three times higher in FBS-containing CMs. Aged cells also showed 1.67- to 2.48-fold increases in the activity due to FBS-containing CM, but not to FBS-free CM. The CM activities were sustained even after 1 year at 4 °C. Molecular weight fractionation showed that the activity was recovered in the fraction above 100 k. Clear and stable cell-growth-promoting activity was confirmed with CMs of commercially available adipose tissue MSCs. The activity was detected in the fraction over 100 k. We propose here the importance of standardizing the production and evaluation of CMs to indicate their specific action. [ABSTRACT FROM AUTHOR]

Inherited deficiency of thymidine phosphorylase (TP), encoded by TYMP, leads to a rare disease with multiple mitochondrial DNA (mtDNA) abnormalities, mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). However, the impact of TP deficiency on lysosomes remains unclear, which are important for mitochondrial quality control and nucleic acid metabolism. Muscle biopsy tissue and skin fibroblasts from MNGIE patients, patients with m.3243 A > G mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and healthy controls (HC) were collected to perform mitochondrial and lysosomal functional analyses. In addition to mtDNA abnormalities, compared to controls distinctively reduced expression of LAMP1 and increased mitochondrial content were detected in the muscle tissue of MNGIE patients. Skin fibroblasts from MNGIE patients showed decreased expression of LAMP2, lowered lysosomal acidity, reduced enzyme activity and impaired protein degradation ability. TYMP knockout or TP inhibition in cells can also induce the similar lysosomal dysfunction. Using lysosome immunoprecipitation (Lyso- IP), increased mitochondrial proteins, decreased vesicular proteins and V-ATPase enzymes, and accumulation of various nucleosides were detected in lysosomes with TP deficiency. Treatment of cells with high concentrations of dThd and dUrd also triggers lysosomal dysfunction and disruption of mitochondrial homeostasis. Therefore, the results provided evidence that TP deficiency leads to nucleoside accumulation in lysosomes and lysosomal dysfunction, revealing the widespread disruption of organelles underlying MNGIE. [ABSTRACT FROM AUTHOR]

Exposure to ultraviolet radiation (UVR) leads to skin DNA damage, specifically in the form of cyclobutane pyrimidine dimers, with thymidine dimers being the most common. Quantifying these dimers can indicate the extent of DNA damage resulting from UVR exposure. Here, a new liquid chromatography-mass spectrometry (LC–MS) method was used to quantify thymidine dimers in the urine after a temporary increase in real-life UVR exposure. Healthy Danish volunteers (n = 27) experienced increased UVR exposure during a winter vacation. Individual exposure, assessed via personally worn electronic UVR dosimeters, revealed a mean exposure level of 32.9 standard erythema doses (SEDs) during the last week of vacation. Morning urine thymidine dimer concentrations were markedly elevated both 1 and 2 days post-vacation, and individual thymidine dimer levels correlated with UVR exposure during the last week of the vacation. The strongest correlation with erythema-weighted personal UVR exposure (Power model, r2 = 0.64, p < 0.001) was observed when both morning urine samples were combined to measure 48-h thymidine dimer excretion, whereas 24-h excretion based on a single sample provided a weaker correlation (Power model, r2 = 0.55, p < 0.001). Sex, age, and skin phototype had no significant effect on these correlations. For the first time, urinary thymidine dimer excretion was quantified by LC–MS to evaluate the effect of a temporary increase in personal UVR exposure in a real-life setting. The high sensitivity to elevated UVR exposure and correlation between urinary excretion and measured SED suggest that this approach may be used to quantify DNA damage and repair and to evaluate photoprevention strategies. [ABSTRACT FROM AUTHOR]

DNA combing and DNA spreading are two central approaches for studying DNA replication fork dynamics genome-wide at single-molecule resolution by distributing labeled genomic DNA on coverslips or slides for immunodetection. Perturbations in DNA replication fork dynamics can differentially affect either leading or lagging strand synthesis, for example, in instances where replication is blocked by a lesion or obstacle on only one of the two strands. Thus, we sought to investigate whether the DNA combing and/or spreading approaches are suitable for resolving adjacent sister chromatids during DNA replication, thereby enabling the detection of DNA replication dynamics within individual nascent strands. To this end, we developed a thymidine labeling scheme that discriminates between these two possibilities. Our data suggests that DNA combing resolves sister chromatids, allowing the detection of strand-specific alterations, whereas DNA spreading typically does not. These findings have important implications when interpreting DNA replication dynamics from data obtained by these two commonly used techniques. [ABSTRACT FROM AUTHOR]

Summary: Background: DNA polymerase gamma (POLG)-related disorders are a group of rare neurodegenerative mitochondrial diseases caused by pathogenic variants in POLG, the gene encoding POLG. Patients may experience a range of signs and symptoms, including seizures, vision loss, myopathy, neuropathy, developmental impairment or regression, and liver failure. The diseases follow a progressive, degenerative course, with most affected individuals dying within 3 months–12 years of diagnosis. At present, there are no effective treatments for POLG-related disorders. Methods: In this study we report the interim 6-month data from a long term open-label, single arm phase 2 trial, in which we assessed the safety and efficacy of combination therapy with deoxycytidine and deoxythymidine (dC/dT) in children with POLG-related disorders. dC/dT was given enterally in powder form, dissolved in water. The primary outcome measures included Newcastle Mitochondrial Disease Scale (NMDS) score, serum growth differentiation factor 15 (GDF-15; a biomarker of mitochondrial dysfunction), electroencephalography (EEG), seizure diary, and blood and urine tests to assess end organ and mitochondrial function. Secondary outcome measures included recording of all adverse events to evaluate the safety of the intervention. The trial is registered with ClinicalTrials.gov, NCT04802707 (https://clinicaltrials.gov/ct2/show/NCT04802707). Data were collected from 14 October, 2021 to 13 December, 2023. Findings: We present 6-month interim data from the first ten people with POLG-related disorders enrolled in the trial, six with Alpers-Huttenlocher syndrome, two with ataxia-neuropathy spectrum, and two who do not fit into a classical POLG-related phenotype. During the 6 months of treatment, NMDS score improved from a mean of 27.3 at baseline to 20.7 at 6 months (estimated difference 6.0; 95% CI 2.5–∞). GDF-15 values remained stable or decreased in all patients; the mean decreased from 1031 pg/ml to 729 pg/ml (estimated difference 200; 95% CI 12–∞). 8/10 patients had abnormal baseline EEG; improvement in EEG was seen in 5 of these 8. There were no significant changes in other blood and urine testing. Regarding adverse events, two patients experienced diarrhea that spontaneously resolved. Interpretation: dC/dT is a promising treatment option for people with POLG-related disorders. Further research is needed to assess the long-term safety and efficacy in POLG-related disorders, as well as safety and efficacy in other mitochondrial DNA depletion disorders. Funding: This study was primarily funded by the Liam Foundation, with additional funding from the Savoy Foundation, Grand Défi Pierre Lavoie Foundation, and Fonds de Recherche du Québec - Santé.

Various chemical modifications have been investigated to improve the therapeutic properties of antisense oligonucleotides. In this study, we synthesized and evaluated two novel thymidine analogs: (S)-5′-C-aminopropyl-2′-O-aminoethyl thymidine and (S)-5′-C-aminopropyl-2′-O-methoxyethyl thymidine. Although both of these novel analogs exhibited robust resistance to nuclease degradation, the (S)-5′-C-aminopropyl-2′-O-methoxyethyl modification demonstrated superior thermal stability when applied to a TC-repeat model sequence. Conversely, the (S)-5′-C-aminopropyl-2′-O-aminoethyl modification was found to influence the secondary structure of DNA/RNA duplexes, resulting in thermal destabilization. Furthermore, a series of (S)-5′-C-aminopropyl-2′-O-methoxyethyl-modified KRAS-targeting locked nucleic acid (LNA) gapmers, termed KR-A gapmers, were prepared and subjected to in vitro testing. The results indicated that the (S)-5′-C-aminopropyl-2′-O-methoxyethyl modification could serve as a viable alternative to LNA, maintaining sufficient antisense activity.

One-carbon metabolism is a universal metabolic process that mediates the transfer of one-carbon units for purine and thymidine synthesis. One-carbon metabolism has been found to be dysregulated in various cancer types due to its role in production of purine and pyrimidine nucleotides, epigenetic program, and redox homeostasis. One-carbon metabolism is composed a network of onecarbon metabolic enzymes. Disturbing the expression and enzymatic activity of these one-carbon metabolic enzymes could lead to fluctuations of metabolites in the tumor microenvironment. Serine hydroxymethyltransferases (SHMTs) and methylenetetrahydrofolate dehydrogenases (MTHFDs) are gradually recognized as important one-carbon metabolic enzymes for regulating tumor initiation and development, representing potential therapeutic targets for anti-tumor strategies. In the review, we primarily focused on the role of SHMTs and MTHFDs in cancer. Several inhibitors targeting MTHFDs and SHMTs have exert its potential to decrease tumor burden and inhibit tumor proliferation, highlighting the potential of targeting one-carbon metabolic enzymes for anti-cancer strategies. [ABSTRACT FROM AUTHOR]

Background: Capecitabine is an oral prodrug of the active metabolite 5-fluorouracil, which has been used effectively in human colorectal, head and neck, and mammary carcinomas. Capecitabine has several properties that make it an attractive treatment option for dogs: (i) it is relatively inexpensive, (ii) it has a short half-life in humans, allowing for rapid plasma concentration changes to be achieved with dosage adjustments, (iii) it is effective for treating carcinomas in humans, for which there are no widely-effective oral chemotherapy options in dogs, and (iv) it is thought to preferentially target cancer cells due to different expression of thymidine phosphorylase, thereby decreasing the risk of off-target side effects. However, capecitabine has not been widely explored as a chemotherapy agent for dogs. The goal of this study was to determine the plasma disposition of capecitabine in dogs following a single oral dose and to document any adverse events associated with capecitabine administration over the course of 5 weeks. Results: Capecitabine was well tolerated throughout the 5-week study period when administered to 5 dogs with naturally occurring carcinomas at 750 mg/m 2 by mouth once daily for 14 consecutive days in a 3-week cycle. No dogs withdrew from the study due to adverse events or other causes. The median AUC 0-last was 890 h · ng/ml (range 750-1100 h · ng/ml); however, the maximum blood concentration and time to reach that concentration of capecitabine was highly variable after a single dose. Conclusions: Capecitabine appears well-tolerated as an oral chemotherapy agent for dogs with carcinomas, although individualized dosing may be necessary, and further studies are warranted. [ABSTRACT FROM AUTHOR]

Background: An accurate and easily accessible method for diagnosing malignancies in local veterinary clinics has not yet been established. Objectives: To investigate the usefulness of serum thymidine kinase 1 (TK1) protein and its autoantibody as tumor biomarkers in dogs. Animals: Serum samples from 1702 dogs were collected from local animal hospitals and referral animal medical centers in South Korea. Methods: TK1 protein OD value and TK1 autoantibody ratio (TK1 autoantibody OD/total IgG OD) in serum samples of dogs classified into healthy controls, group with nontumor disease, group with benign and group with malignant tumors were measured using lateral flow immunochromatographic assay methods. Results: TK1 autoantibody levels were significantly higher in malignant tumor group (median 0.71) than in healthy controls (median 0.34), group with nontumor disease (median 0.34), and group with benign tumor (median 0.32, Welch t test, P <.0001). They were also significantly different among dogs with carcinomas (median 0.77), hematopoietic tumors (median 0.71), and sarcomas (median 0.56) than in healthy controls (median 0.34, post hoc Games‐Howell test, P <.0001). In the receiver operating characteristic curve of TK1 protein, AUC was 0.633 (95% CI: 0.592‐0.675, P <.0001). The AUC of TK1 autoantibody ratio was 0.758 (95% CI: 0.723‐0.793, P <.0001). Conclusions and Clinical Importance: TK1 autoantibody is a potentially useful biomarker for differentiating between healthy and tumor‐bearing dogs, better than TK1 protein measurement. However, both were inadequate when used as single biomarkers for screening dogs to discover occult malignant tumors. [ABSTRACT FROM AUTHOR]

Background: Moringa peregrina is widely used in the traditional medicine of the Arabian Peninsula to treat various ailments, because it has many pharmacologically active components with several therapeutic effects. Objective: This study aimed to investigate the inhibitory effect of Moringa peregrina seed ethanolic extract (MPSE) against key enzymes involved in human pathologies, such as angiogenesis (thymidine phosphorylase), diabetes (α-glucosidase), and idiopathic intracranial hypertension (carbonic anhydrase). In addition, the anticancer properties were tested against the SH-SY5Y (human neuroblastoma). Results: MPSE extract significantly inhibited a-glucosidase, thymidine phosphorylase, and carbonic anhydrase with half-maximal inhibitory concentrations (IC50) values of 303.1 ± 1.3, 471.30 ± 0.3, and 271.30 ± 5.1 µg/mL, respectively. Furthermore, the antiproliferative effect of the MPSE was observed on the SH-SY5Y cancer cell line with IC50 values of 55.1 µg/mL. Conclusions: MPSE has interesting inhibitory capacities against key enzymes and human neuroblastoma cancer cell line. [ABSTRACT FROM AUTHOR]

Herpes infection is considered a global health burden. Developing new therapeutic strategies for treating herpes is a challenging research problem. This study aimed to investigate and compare the potential antiviral activity of Sophocarpine and Chelerythrine alkaloids against Herpes Simplex Virus Type-1 thymidine kinase in the presence of acyclovir, an established antiviral drug. The study utilized PyRX docking and Auto Dock 4 softwares. The comparative analysis of the docking results showed that both Sophocarpine and Chelerythrine had promising binding affinities, indicating potential antiviral activity. A redocking experiment with acyclovir to test our molecular docking approach confirmed predicted binding modes, validating the reliability of this approach. This is a comparative study of results obtained by two different docking softwares. The results pave the way for further in vitro and in vivo investigation, providing a foundation for developing novel anti-herpes therapeutic agents. [ABSTRACT FROM AUTHOR]

A quantitative analysis of the relationship between the structure and inhibitory activity against the herpes simplex virus thymidine kinase (HSV-TK) was performed for the series of 5-ethyluridine, N2-guanine, and 6-oxopurines derivatives with pronounced anti-herpetic activity (IC50 = 0.09 ÷ 160,000 μmol/L) using the GUSAR 2019 software. On the basis of the MNA and QNA descriptors and whole-molecule descriptors using the self-consistent regression, 12 statistically significant consensus models for predicting numerical pIC50 values were constructed. These models demonstrated high predictive accuracy for the training and test sets. Molecular fragments of HSV-1 and HSV-2 TK inhibitors that enhance or diminish the anti-herpetic activity are considered. Virtual screening of the ChEMBL database using the developed QSAR models revealed 42 new effective HSV-1 and HSV-2 TK inhibitors. These compounds are promising for further research. The obtained data open up new opportunities for developing novel effective inhibitors of TK. [ABSTRACT FROM AUTHOR]

Purpose: Construction of a nomogram model based on Thymidine kinase 1 (TK1) in combination with inflammatory indicators and tumor markers to predict the probability of recurrence in mid- to late-stage cervical cancer.Methods: One hundred fourteen instances of intermediate and advanced cervical cancer admitted to our hospital's radiotherapy department between June 2017 and January 2023 were retrospectively studied. Logistic regression analysis includes variables relevant for univariate analysis. Meaningful indications from multifactor analysis were included in the nomogram model, the model's correctness was evaluated using the C-index, and the model's effectiveness was assessed using calibration curves, clinical decision curves, and clinical impact curves.Results: A nomogram model was created due to the logit regression analysis that revealed the squamous cell carcinoma antigen (SCC) and TK1 as independent recurrence predictors following cervical cancer radiation (P< 0.05). The C index and Area Under the Curve (AUC) were 0.79 (95% CI 0.67– 0.91). The AUC and C-index were both more extraordinary than those of TNM staging alone (C-index 0.57, 95% CI 0.43– 0.71) and SCC alone (C-index 0.67, 95% CI 0.51– 0.82). Calibration curves, Decision Curve Analysis (DCA), and clinical impact curves (CIC) indicate that the model predicts probabilities more accurately.Conclusion: The nomogram model based on TK1 combined with inflammatory markers and tumor markers is more reliable than the TNM staging and SCC systems alone for forecasting recurrence after radiotherapy in intermediate- and advanced-stage cervical cancer. It is also a cheap, practical, and simple-to-obtain model that can supplement the TNM staging system for forecasting prognosis and significantly enhances clinicians' decision-making. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to investigate the role of thymidine kinase 1 (TK1) levels in hepatocellular carcinoma (HCC) prognosis and to develop a nomogram for predicting HCC prognosis. Method: In this study, 1066 HCC patients were enrolled between August 2018 and April 2022. TK1 levels were measured within one week before enrollment, and the relationship with HCC prognosis was evaluated. Next, all patients were randomly assigned to the training set (70%, n = 746) and the validation set (30%, n = 320). We used multivariate Cox analysis to find independent prognostic factors in the training set to construct a nomogram. The predictive power of the nomogram was assessed using receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA). The optimal critical value of TK1 was determined as 2.35 U/L using X-tile software. Result: Before and after propensity score matching (PSM), the median overall survival (mOS) of the low-TK1 group (< 2.35 U/L) remained significantly longer than that of the high-TK1 group (≥ 2.35 U/L) (48.1 vs 16.5 months, p < 0.001; 75.7 vs 19.8 months, p = 0.001). Moreover, multivariate Cox analysis showed that the low TK1 level was an independent positive prognostic indicator. Additionally, the area under the ROC curve for predicting the 1-year, 2-year, and 3-year survival rates was 0.770, 0.758, and 0.805, respectively. Conclusions: TK1 could serve as a prognostic marker for HCC. In addition, the nomogram showed good predictive capability for HCC prognosis. [ABSTRACT FROM AUTHOR]

Objective • This study aims to analyze the diagnostic and prognostic value of serum thymidine kinase (TK1), squamous cell carcinoma antigen (SCC-Ag), and mucin-1 (MUC-1) in cervical cancer. Methods • This retrospective study included 85 cervical cancer patients as the experimental group treated at our hospital’s obstetrics and gynecology department from January 2016 to January 2019. The benign group also consisted of 85 patients with benign lesions treated during the same period, and the comparison group comprised 85 patients with healthy physical examinations at the same time. Results • Serum levels of TK1, SCC-Ag, and MUC-1 were significantly higher in the experimental group than in the benign group and higher in the benign group than in the comparison group (P < .05). Additionally, serum TK1, SCCAg, and MUC-1 were higher in the lymph node metastasis group, infiltration depth > 1/2 group, tumor diameter ≥ 4 cm group, and stage III-IV group compared to the non-lymph node metastasis group, infiltration depth ≤ 1/2 group, tumor diameter <4 cm group, and stage I-II group (P < .05). No significant differences in serum TK1, SCC-Ag, and MUC-1 among different pathological types and age groups (P > .05). Moreover, serum TK1, SCC-Ag, and MUC-1 levels were higher in the deceased group compared to the survivor group (P < .05). These markers were negatively correlated with survival time (r value = -0.524, -0.428, -0.516), indicating that as the severity of cervical cancer increased, serum TK1, SCCAg, and MUC-1 concentrations also increased. The levels of these markers were significantly higher in deceased patients compared to survivors. Conclusions • Serum levels of TK1, SCC-Ag, and MUC-1 show promise as biomarkers for cervical cancer diagnosis and prognosis. TK1 and SCC-Ag are elevated, while MUC-1 is decreased in cervical cancer patients. Further research is warranted to confirm these findings and explore additional biomarkers. [ABSTRACT FROM AUTHOR]

Nucleic acid lateral flow assay (NALFA) with gold nanoparticles (AuNPs) as colorimetric probes have been extensively adopted for point-of-care testing (POCT). However, the sensitivity of NALFA still needs to be improved. Herein, DNA-gold nanoaggregate (DNA-AuNA) was assembled as a signal amplification probe of NALFA for sensitive detection of tumor marker TK1 mRNA. Four functional oligonucleotides with complementary pairs were assembled to form DNA-AuNA that coupled more AuNPs to improve sensitivity. Thus, the limit of detection (LOD) was 0.36 pM, which is lower than that of conventional AuNPs-based NALFA. Moreover, the bioassay showed good reproducibility, stability, and specificity for detecting TK1 mRNA. The detection of TK1 mRNA in human serum was also satisfactory. Therefore, DNA-AuNA-based NALFA provides a sensitive method for portable detection of TK1 mRNA. [ABSTRACT FROM AUTHOR]

Objective: To observe the efficacy of transcatheter arterial chemoembolization (TACE) combine with iodine 125 seed implantation in the treatment of primary hepatic cancer (PHC) combined with portal vein tumor thrombus (PVTT) and its impact on serum tumor specific growth factor (TSGF), thymidine kinase 1 (TK-1), and soluble B7-H3 (s B7-H3) . Methods: 120 patients with PHC combined with PVTT who were admitted to the Cancer Hospital Affiliated to Xinjiang Medical University from January 2019 to January2020 were selected. They were divided into control group (treated with TACE, 60 cases) and combined group (treated with TACE combined with iodine 125 seed implantation, 60 cases) according to the random number table method. The efficacy, hepatic function indexes[alanine aminotransferase (ALT), aspartate transaminase (AST), total bilirubin (TBi L) ], serum tumor markers [alpha fetoprotein (AFP),cytokeratin-19 fragment (CYFRA21-1) and carcinoembryonic antigen (CEA) ], TSGF, TK-1 and s B7-H3 were observed. Followed up for3 years, the difference in overall survival time (OS) between two groups of patients was analyzed by Kaplan-Meier curve (Log-Rank test) .Results: The total clinical effective rate in combined group was higher than that in control group (P＜0.05) . Compared with before treatment, ALT, AST and TBi L decreased in two groups after treatment, and those in combined group were lower than those in control group during the same period (P＜0.05) . Compared with before treatment, AFP, CYFRA21-1 and CEA decreased in two groups after treatment,and those in combined group were lower than those in control group during the same period (P＜0.05) . Compared with before treatment,TSGF, TK-1 and s B7-H3 decreased in two groups after treatment, and those in combined group were lower than those in control group during the same period (P＜0.05) . The OS in combined group was longer than that in control group (P＜0.05) . Conclusion: The TACE combined with iodine 125 seed implantation for the treatment of patients with PHC combine with PVTT, which can improve clinical efficacy, reduce serum tumor marker levels, reduce hepatic function damage, extend OS of patients and regulate serum TSGF, TK-1 and s B7-H3 levels. [ABSTRACT FROM AUTHOR]

Nucleoside analogs are an important, well-established class of clinically useful medicinal agents that exhibit potent antimicrobial activity. Thus, we designed to explore the synthesis and spectral characterization of 5′-O-(myristoyl)thymidine esters (2–6) for in vitro antimicrobial, molecular docking, molecular dynamics, SAR, and POM analyses. An unimolar myristoylation of thymidine under controlled conditions furnished the 5′-O-(myristoyl)thymidine and it was further converted into four 3′-O-(acyl)-5′-O-(myristoyl)thymidine analogs. The chemical structures of the synthesized analogs were ascertained by analyzing their physicochemical, elemental, and spectroscopic data. In vitro antimicrobial tests along with PASS, prediction indicated expectant antibacterial functionality of these thymidine esters compared to the antifungal activities. In support of this observation, their molecular docking studies have been performed against lanosterol 14α-demethylase (CYP51A1) and Aspergillus flavus (1R51) and significant binding affinities and non-bonding interactions were observed. The stability of the protein-ligand complexes was monitored by a 100 ns MD simulation and found the stable conformation and binding mode in a stimulating environment of thymidine esters. Pharmacokinetic predictions were studied to assess their ADMET properties and showed promising results in silico. SAR investigation indicated that acyl chains, lauroyl (C-12) and myristoyl (C-14), combined with deoxyribose, were most effective against the tested bacterial and fungal pathogens. The POM analyses provide the structural features responsible for their combined antibacterial/antifungal activity and provide guidelines for further modifications, with the aim of improving each activity and selectivity of designed drugs targeting potentially drug-resistant microorganisms. It also opens avenues for the development of newer antimicrobial agents targeting bacterial and fungal pathogens. A novel series of 5´-O-(myristoyl)thymidine derivatives were synthesized and characterized by FTIR, 1H-NMR, 2D-NMR, 13C-NMR, mass and physicochemical studies. In vitro antimicrobial susceptibility revealed that alkyl chain and aromatic substituents can improve the antimicrobial efficacy of the thymidine structure which was also supported by PASS enumeration. Molecular docking study against lanosterol 14α-demethylase (CYP51A1) and Aspergillus flavus (1R51) exhibited a promising binding score and interaction in the catalytic active site. A 100ns MD simulation revealed the stable conformation and binding pattern in a stimulating environment of thymidine derivatives. ADMET analysis revealed that most of the compounds are non-toxic and most of them have an inhibitory property to the CYP1A2 and CYP3A4 In silico and POM analyses provide substantial ideas about the structural features responsible for their combined antibacterial/antifungal agents and provide guidelines for further modifications. [ABSTRACT FROM AUTHOR]

Deficiency in thymidine kinase 2 (TK2) causes mitochondrial DNA depletion. Liver mitochondria are severely affected in Tk2 complete knockout models and have been suggested to play a role in the pathogenesis of the Tk2 knockout phenotype, characterized by loss of hypodermal fat tissue, growth retardation and reduced life span. Here we report a liver specific Tk2 knockout (KO) model to further study mechanisms contributing to the phenotypic changes associated with Tk2 deficiency. Interestingly, the liver specific Tk2 KO mice had a normal life span despite a much lower mtDNA level in liver tissue. Mitochondrial DNA encoded peptide COXI did not differ between the Tk2 KO and control mice. However, the relative liver weight was significantly increased in the male Tk2 KO mouse model. Histology analysis indicated an increased lipid accumulation. We conclude that other enzyme activities can partly compensate Tk2 deficiency to maintain mtDNA at a low but stable level throughout the life span of the liver specific Tk2 KO mice. The lower level of mtDNA was sufficient for survival but led to an abnormal lipid accumulation in liver tissue. [ABSTRACT FROM AUTHOR]

Thymidine glycol (Tg) is the most prevalent form of oxidatively induced pyrimidine lesions in DNA. Tg can arise from direct oxidation of thymidine in DNA. In addition, 5-methyl-2-deoxycytidine (5-mdC) can be oxidized to 5-mdC glycol, and its subsequent deamination also yields Tg. However, Tgs distribution in the human genome remains unknown. Here, we presented a DNA-protein cross-linking sequencing (DPC-Seq) method for genome-wide mapping of Tg in human cells. Our approach capitalizes on the specificity of a bifunctional DNA glycosylase, i.e., NTHL1, for the covalent labeling, as well as DPC pulldown, SDS-PAGE fractionation, and membrane transfer for highly efficient and selective enrichment of Tg-bearing DNA. By employing DPC-Seq, we detected thousands of Tg sites in the human genome, where dual ablation of NTHL1 and NEIL1, the major DNA glycosylases responsible for Tg repair, led to pronounced increases in the number of Tg peaks. In addition, Tg is depleted in genomic regions associated with active transcription but enriched at nucleosome-binding sites, especially at heterochromatin sites marked with H3K9me2. Collectively, we developed a DPC-Seq method for highly efficient enrichment of Tg-containing DNA and for genome-wide mapping of Tg in human cells. Our work offers a robust tool for future functional studies of Tg in DNA, and we envision that the method can also be adapted for mapping other modified nucleosides in genomic DNA in the future.

One of the most essential health problems is cancer, the first or second cause of death worldwide. Head and neck cancers are hard to detect due to non-specific symptoms. The treatment often relies on a combination of radio and chemotherapy. For this reason, the research of new anticancer compounds is fundamental. The natural and synthetic compounds with 1,4-naphthoquinone scaffold is characterized by high anticancer activity. The study aimed to evaluate the synthesis and anticancer activity of hybrids 1,4-naphthoquinone with thymidine derivatives. The series of compounds allows us to check the influence of the substituent in the C3′ position of the thymidine moiety on the cytotoxicity against squamous cancer cell lines (SCC-9 and SCC-25) and submandibular gland cancer (A-253). An annexin V/propidium iodide (PI) co-staining assay shows that derivatives cause the apoptotic in SCC-25 and A-253 cell lines. The molecular docking study examined the interaction between the active site of the BCL-2 protein and the hybrids. [ABSTRACT FROM AUTHOR]

Pancreatic ductal adenocarcinoma (PDAC) patients might benefit from a biomarker to more precisely prognosticate their overall survival to make more informed treatment and surveillance decisions. The aim of the study was to assess the circulating biomarker Thymidine kinase (TK) activity in samples from patients with PDAC to improve prognostic precision. Using the sensitive TK activity (TKa) assay DiviTum®, serum samples from 60 PDAC patients were analyzed. Median TKa value for patients with PDAC was 931 Du/L. TK activity <931 and CA19-9 < 37 was prognostic for a longer survival, compared to patients with any or both TK activity >931 and CA19-9 > 37, with median 41.3 vs 8.6 months from sample to death (p < 0.001), and 3-year survival was 55.6% vs 8.9% (p < 0.001). Hazard ratio was 2.81 if any or both of TK or CA19-9 were above the cut-off value (p < 0.05). TKa in combination with CA19-9 outperforms each marker individually for prediction of survival. Overall survival is longer in patients with both TKa <931 Du/L and CA19-9 < 37. Further studies of TKa levels at different disease stages and correlation to outcome is warranted to find the full potential clinical usage of the TKa marker in PDAC. [ABSTRACT FROM AUTHOR]

While modern molecular methods have decisively accelerated and improved microbiological diagnostics, phenotypic variants still pose a challenge for their detection, identification and characterization. This particularly applies if they are unstable and hard to detect, which is the case for the small-colony-variant (SCV) phenotype formed by staphylococci. On solid agar media, staphylococcal SCVs are characterized by tiny colonies with deviant colony morphology. Their reduced growth rate and fundamental metabolic changes are the result of their adaptation to an intracellular lifestyle, regularly leading to specific auxotrophies, such as for menadione, hemin or thymidine. These alterations make SCVs difficult to recognize and render physiological, biochemical and other growth-based methods such as antimicrobial susceptibility testing unreliable or unusable. Therefore, diagnostic procedures require prolonged incubation times and, if possible, confirmation by molecular methods. A special approach is needed for auxotrophy testing. However, standardized protocols for SCV diagnostics are missing. If available, SCVs and their putative parental isolates should be genotyped to determine clonality. Since their detection has significant implications for the treatment of the infection, which is usually chronic and relapsing, SCV findings should be specifically reported, commented on, and managed in close collaboration with the microbiological laboratory and the involved clinicians. [ABSTRACT FROM AUTHOR]

Objective: To investigate the diagnostic value of contrast enhanced ultrasound combined with serum human epididymal secreted protein 4 (HE4), carbohydrate antigen 125 (CA125), thymidine kinase 1 (TK1) and tumor abnormal protein (TAP) in endometrial malignant lesions. Methods: From January 2019 to January 2022, 95 patients with endometrial lesions who underwent contrast enhanced ultrasound examination in the Ultrasound Department of the Jinan People's Hospital were selected.The levels of serum HE4, CA125, TK1 and TAP were detected. The starting enhancement time, peak time, peak intensity, gradient and area under the TIC curve (TIC-AUC) of the contrast parameters were obtained through contrast enhanced ultrasound examination. The value of contrast enhanced ultrasound parameters combined with serum HE4, CA125, TK1, TAP in diagnosis endometrial malignant lesions was analyzed by receiver operating characteristic (ROC) curve. Results: According to the pathological results,the patients were divided into malignant group (37 cases) and benign group (58 cases). The peak intensity, TIC-AUC, the levels of serum HE4, CA125, TK1 and TAP in the malignant group were higher than those in the benign group (P＜0.05), there were no significant differences in the beginning enhancement time, peak time and gradient between malignant group and benign group(P>0.05). The area under curve for differential diagnosis of endometrial malignant lesions with peak intensity, TIC-AUC, HE4, CA125, TK1 and TAP was 0.767, 0.676, 0.656, 0.691, 0.713 and 0.721, and the area under curve for diagnosis of endometrial malignant lesions with combined peak intensity, TIC-AUC, HE4, CA125, TK1 and TAP was 0.896, which was higher than that of differential diagnosis with single index. Conclusion: The combination of peak intensity of contrast enhanced ultrasound parameters, TIC-AUC and serum HE4, CA125, TK1, TAP has high value in diagnosis benign and malignant endometrial lesions. [ABSTRACT FROM AUTHOR]

The thymidine kinase (TK) and DNA polymerase (pol) genes of the herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2) are two important genes involved in antiviral resistance. We investigated the genetic polymorphisms of the HSV-TK and pol genes in clinical isolates from Korean HSV-infected patients using next-generation sequencing (NGS) for the first time in Korea. A total of 81 HSV-1 and 47 HSV-2 isolates were examined. NGS was used to amplify and sequence the TK and pol genes. Among the 81 HSV-1 isolates, 12 and 17 natural polymorphisms and 9 and 23 polymorphisms of unknown significance in TK and pol were found, respectively. Two HSV-1 isolates (2.5%) exhibited the E257K amino acid substitution in TK, associated with antiviral resistance. Out of 47 HSV-2 isolates, 8 natural polymorphisms were identified in TK, and 9 in pol, with 13 polymorphisms of unknown significance in TK and 10 in pol. No known resistance-related mutations were observed in HSV-2. These findings contribute to our understanding of the genetic variants associated with antiviral resistance in HSV-1 and HSV-2 in Korea, with frequencies of known antiviral resistance-related mutations of 2.5% and 0% in HSV-1 and HSV-2, respectively. [ABSTRACT FROM AUTHOR]

Introduction: Heterocyclic compounds have diverse biological activities and potential in drug development. This study aims to synthesize novel compounds with two 1,2,4-triazole cores and evaluate their biological properties, particularly their inhibitory activity against thymidine phosphorylase (TP), an enzyme involved in various physiological processes.Methods: The compounds were synthesized by reacting 5,5'-butane-bis-1,2,4-triazole derivatives with prenyl bromide. Characterization involved various techniques, including spectroscopy and elemental analysis. Antimicrobial potential was evaluated against bacteria and fungi, with comparative antibiotics as references. Inhibitory activity against TP was assessed, and molecular docking studies were conducted.Results: Six compounds were successfully synthesized and their structures confirmed. The synthesized triazole derivatives exhibited high biological activity, with compounds 2 and 6 showing the most promising TP inhibition. Molecular docking studies revealed interactions between compound 2 and TP, involving nine amino acids.Discussion: The synthesis of novel compounds with two 1,2,4-triazole cores contributes significantly to bis-triazole research. These compounds have potential as anti-tumor agents due to their inhibitory activity against TP, a crucial enzyme in tumor growth and metastasis. Comparative evaluation against antibiotics highlights their potency. Docking results provide insights into their interactions with TP, supporting their potential as potent TP inhibitors. Further research should focus on evaluating their efficacy in biological models, understanding their mechanisms of action, and optimizing their activities.Conclusion: The synthesized compounds with two 1,2,4-triazole cores exhibit significant biological activity, including strong TP inhibition and broad-spectrum antimicrobial effects. These findings emphasize their potential as anti-tumor agents and the need for further exploration and optimization. Future research should focus on evaluating their efficacy in biological models, understanding their mechanisms of action, and developing more potent bis-triazole derivatives for drug discovery efforts. The combined results from assays and docking studies support the therapeutic potential of these compounds as anti-tumor agents. [ABSTRACT FROM AUTHOR]

5‐Hydroxymethyl‐pyrimidine‐based nucleobases have attracted attention in the last years due to their important role in gene regulation. It prompted the development of efficient routes to the corresponding nucleoside building blocks for further incorporation into oligonucleotides. Several pathways have been employed in recent years to access properly protected 5‐hydroxymethyl‐pyrimidine based nucleosides, including hydroxymethylation of 2'‐deoxyuridine, radical bromination of thymidine followed by bromine substitution, or carbonylative coupling through Stille conditions starting from 5‐iodo‐2'‐deoxyuridine. In this study, we review the different approaches currently used to introduce the 5‐hydroxymethyl moiety, we reinvestigate some of them, and finally, we propose an alternative route based on the oxidation of the methyl of thymidine followed by its reduction that allows access to protected 5‐hydroxymethyl‐2'‐deoxyuridine in a simple way with good yields. Finally, we present some examples of application including the synthesis of base J and 5‐azidomethyl‐2'‐deoxyuridine. [ABSTRACT FROM AUTHOR]

Hand–foot syndrome (HFS) is a common adverse effect of capecitabine affecting the quality of life of cancer patients. To enhance the tolerability of capecitabine, this work evaluated the incorporation of quercetin into topical collagen matrix formula to target thymidine phosphorylase enzyme, oxidative stress, and apoptosis underlying HFS. Forty Sprague Dawley rats were allocated to four equal groups. The control group received distilled water orally. HFS was induced by oral capecitabine (200 mg/kg/day) for 21 days. The untreated HFS group received no treatment. In the treated groups, topical collagen and quercetin-incorporated collagen matrix formula were administered concomitantly with the HFS induction protocol. Treatment with quercetin-incorporated collagen matrix showed a significant decrease in thymidine phosphorylase level compared with the untreated and collagen-treated groups. Treatment with quercetin-incorporated collagen matrix showed a significant decrease in malondialdehyde and caspase-3 levels, and a significant increase in the total antioxidant capacity of the skin and B cell lymphoma/leukemia 2 levels compared with the untreated group. Additionally, a significant improvement in the gross picture and histopathological score of HFS was observed. In conclusion, the quercetin-incorporated collagen matrix is a promising formula for the prevention of HFS, due to the targeted effect on thymidine phosphorylase and subsequent antioxidant and antiapoptotic effects. [ABSTRACT FROM AUTHOR]

Introduction: Hepatocellular carcinoma (HCC) is one of the most serious cancers. Circular RNA (circRNA) has been reported to regulate the progression of HCC. Herein, the role of circ_0102543 in HCC tumorigenesis was investigated. Materials: The expression levels of circ_0102543, microRNA‐942‐5p (miR‐942‐5p), and small glutamine rich tetratricopeptide repeat co‐chaperone beta (SGTB) were detected by quantitative real‐time PCR (qRT‐PCR). 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium Bromide (MTT) assay, thymidine analog 5‐ethynyl‐2'‐deoxyuridine (EDU) assay, transwell assay, and flow cytometry were conducted to explore the function of circ_0102543 in HCC cells and the regulatory mechanism among circ_0102543, miR‐942‐5p and SGTB in HCC cells. Western blot examined the related protein levels. Results: The expression of circ_0102543 and SGTB was decreased in HCC tissues, while the expression of miR‐942‐5p was increased. Circ_0102543 acted as a sponge for miR‐942‐5p, and SGTB was the target of miR‐942‐5p. Circ_0102543 up‐regulation hindered tumor growth in vivo. In vitro experiments showed that overexpression of circ_0102543 significantly repressed the malignant behaviors of HCC cells, while co‐transfection of miR‐942‐5p partially attenuated these effects mediated by circ_0102543. In addition, SGTB knockdown increased the proliferation, migration, and invasion of HCC cells inhibited by miR‐942‐5p inhibitor. Mechanically, circ_0102543 regulated SGTB expression in HCC cells by sponging miR‐942‐5p. Conclusion: Overexpression of circ_0102543 suppressed proliferation, migration, and invasion of HCC cells by regulating the miR‐942‐5p/SGTB axis, suggesting that circ_0102543/miR‐942‐5p/SGTB axis may be a potential therapeutic target for HCC. [ABSTRACT FROM AUTHOR]

O2- and O4-alkylated thymidine lesions are known to be poorly repaired and persist in mammalian tissues. To understand how mammalian cells sense the presence and regulate the repair of these lesions, we employed a quantitative proteomic method to discover regioisomeric O2- and O4-n-butylthymidine (O2- and O4-nBudT)-binding proteins. We were able to identify 21 and 74 candidate DNA damage recognition proteins for O2-nBudT- and O4-nBudT-bearing DNA probes, respectively. Among these proteins, DDB1 and DDB2 selectively bind to O2-nBudT-containing DNA, whereas three high-mobility group (HMG) proteins (i.e., HMGB1, HMGB2, and mitochondrial transcription factor A (TFAM)) exhibit preferential binding to O4-nBudT-bearing DNA. We further demonstrated that TFAM binds directly and selectively with O4-alkyldT-harboring DNA, and the binding capacity depends mainly on the HMG box-A domain of TFAM. We also found that TFAM promotes transcriptional mutagenesis of O4-nBudT and O4-pyridyloxobutylthymidine, which is a DNA adduct induced by tobacco-specific N-nitrosamines, in vitro and in human cells. Together, we explored, for the first time, the interaction proteomes of O-alkyldT lesions, and our study expanded the functions of TFAM by revealing its capability in the recognition of O4-alkyldT-bearing DNA and uncovering its modulation of transcriptional mutagenesis of these lesions in human cells.

Simple Summary: Several procedures have been developed to infer cell-cycle time and the duration of the cycle phases, including tritiated thymidine autoradiography and the immunodetection of thymidine analogues after their incorporation into replicating DNA. These methods have supplied important insights to reveal, on fixed tissue sections and using light or electron microscopy, the proliferative behavior of different cell types under different experimental contexts. Thymidine analogous labeling has provided knowledge about cell growth kinetics that would never have been obtained by histological methods alone. Tritiated thymidine autoradiography, 5-bromo-2′-deoxyuridine (BrdU) 5-chloro-2′-deoxyuridine (CldU), 5-iodo-2′-deoxyuridine (IdU), and 5-ethynyl-2′-deoxyiridine (EdU) labeling have been used for identifying the fraction of cells undergoing the S-phase of the cell cycle and to follow the fate of these cells during the embryonic, perinatal, and adult life in several species of vertebrate. In this current review, I will discuss the dosage and times of exposition to the aforementioned thymidine analogues to label most of the cells undergoing the S-phase of the cell cycle. I will also show how to infer, in an asynchronous cell population, the duration of the G1, S, and G2 phases, as well as the growth fraction and the span of the whole cell cycle on the base of some labeling schemes involving a single administration, continuous nucleotide analogue delivery, and double labeling with two thymidine analogues. In this context, the choice of the optimal dose of BrdU, CldU, IdU, and EdU to label S-phase cells is a pivotal aspect to produce neither cytotoxic effects nor alter cell cycle progression. I hope that the information presented in this review can be of use as a reference for researchers involved in the genesis of tissues and organs. [ABSTRACT FROM AUTHOR]

Bacterial thymidylate kinase (TMK) is a member of nucleoside monophosphate kinases and recently becomes a protein of interest in the discovery of new antibacterial agents. Thymidylate kinase is a highly conserved enzyme in the pyrimidine salvage pathway that catalyses the synthesis of thymidine 5'-triphosphate, an essential precursor for the synthesis of DNA-building block, thymidylate. Several scaffolds like bicyclic nucleosides, thiourea-substituted β-thymidines, benzyl thymines, thymidine analogues, naphthofuranones, imidazopyridinones, sulfonylpiperidines, fused cyanopyridone, piperidinyl thymines etc. have been investigated for their inhibitory activity against TMK from different bacterial strains. Several TMK inhibitors exhibited potent antibacterial activity, specifically against Mycobacterium tuberculosis, Staphylococcus aureus, Streptococcus pneumoniae,Enterococcus faecium and Enterococcus faecalis. In the present review we discuss bacterial TMK inhibitors, and their associated antibacterial activities reported in literature. This review provides a useful source of structural information which may be utilized for the design of TMK inhibitors possessing potent antibacterial activity. [ABSTRACT FROM AUTHOR]

Diffuse large B‐cell lymphoma (DLBCL) is frequently treated with chemotherapy incorporating cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP), which induces remission in 80% to 95% of cases. However, not all dogs derive meaningful benefit from CHOP, and prognostic factors for dogs with DLBCL are poorly defined. Serum thymidine kinase 1 (TK1) activity, a marker of tumour cell proliferation, has shown promising initial results as a prognostic biomarker in dogs with multicentric lymphomas. The purpose of this study was to determine if baseline serum TK1 activity is associated with clinical outcome in dogs with CHOP‐treated DLBCL. Baseline serum TK1 activity was measured in banked sera from 98 dogs with CHOP‐treated DLBCL using a commercially available ELISA kit. Data on other potential prognostic factors were abstracted retrospectively from electronic medical records. Multivariable statistical methods were used to identify associations between TK1 and other potential prognostic factors with progression‐free survival (PFS) and attainment of complete remission. TK1 activity at baseline was not associated with PFS (p =.299) or attainment of complete remission (p =.910) following CHOP chemotherapy. Of the other prognostic factors analysed, only purebred (vs. mixed breed) status (HR 8.81, 95% CI 1.68–46.30, p =.010), attainment of complete (vs. partial) remission (HR 0.09, 95% CI 0.02–0.49, p =.006), and baseline serum C‐reactive protein concentration (HR 1.19, 95% CI 1.07–1.32, p =.001) were independently associated with PFS. Based on these findings, baseline serum TK1 activity does not appear to be a useful prognostic biomarker in dogs with CHOP‐treated DLBCL. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the structural and biological features of G-quadruplex (G4) aptamers as promising antiproliferative compounds affecting the STAT3 signalling pathway. Targeting the STAT3 protein through high-affinity ligands to reduce its levels or activity in cancer has noteworthy therapeutic potential. T40214 (STAT) [(G3C)4] is a G4 aptamer that can influence STAT3 biological outcomes in an efficient manner in several cancer cells. To explore the effects of an extra cytidine in second position and/or of single site-specific replacements of loop residues in generating aptamers that can affect the STAT3 biochemical pathway, a series of STAT and STATB [GCG2(CG3)3C] analogues containing a thymidine residue instead of cytidines was prepared. NMR, CD, UV, and PAGE data suggested that all derivatives adopt dimeric G4 structures like that of unmodified T40214 endowed with higher thermal stability, keeping the resistance in biological environments substantially unchanged, as shown by the nuclease stability assay. The antiproliferative activity of these ODNs was tested on both human prostate (DU145) and breast (MDA-MB-231) cancer cells. All derivatives showed similar antiproliferative activities on both cell lines, revealing a marked inhibition of proliferation, particularly at 72 h at 30 µM. Transcriptomic analysis aimed to evaluate STAT's and STATB's influence on the expression of many genes in MDA-MB-231 cells, suggested their potential involvement in STAT3 pathway modulation, and thus their interference in different biological processes. These data provide new tools to affect an interesting biochemical pathway and to develop novel anticancer and anti-inflammatory drugs. [ABSTRACT FROM AUTHOR]

A styrylpyridine-containing cyclophane with diethylenetriamine linkers is presented as a host system whose association with representative nucleotides was examined with photometric and fluorimetric titrations. The spectrometric titrations revealed the formation of 1:1 complexes with log Kb values in the range of 2.3–3.2 for pyrimidine nucleotides TMP (thymidine monophosphate), TTP (thymidine triphosphate) and CMP (cytidine monophosphate) and 3.8–5.0 for purine nucleotides AMP (adenosine monophosphate), ATP (adenosine triphosphate), and dGMP (deoxyguanosine monophosphate). Notably, in a neutral buffer solution, the fluorimetric response to the complex formation depends on the type of nucleotide. Hence, quenching of the already weak fluorescence was observed with the purine bases, whereas the association of the cyclophane with pyrimidine bases TMP, TTP, and CMP resulted in a significant fluorescence light-up effect. Thus, it was demonstrated that the styrylpyridine unit is a useful and complementary fluorophore for the development of selective nucleotide-targeting fluorescent probes based on alkylamine-linked cyclophanes. [ABSTRACT FROM AUTHOR]

Some patients with metastatic breast cancer (MBC) stay on endocrine therapy (ET) for years and others progress quickly. Serum thymidine kinase activity (TKa), an indicator of cell-proliferation, is a potential biomarker for monitoring ET and predicting MBC outcome. We have previously reported TKa as being prognostic in MBC in SWOG S0226. Here, new data on progression within 30/60 days post sampling, with a new, FDA approved version of DiviTum®TKa highlighting differences vs. a Research Use Only version is reported. 1,546 serum samples from 454 patients were assessed, collected at baseline and at 4 subsequent timepoints during treatment. A new predefined cut-off tested the ability to predict disease progression. A new measuring unit, DuA (DiviTum® unit of Activity) is adopted. A DiviTum®TKa score <250 DuA provides a much lower risk of progression within 30/60 days after blood draw, the negative predictive value (NPV) was 96.7% and 93.5%, respectively. Patients <250 DuA experienced significantly longer progression-free survival and overall survival, demonstrated at baseline and for all time intervals. DiviTum®TKa provides clinically meaningful information for patients with HR+ MBC. Low TKa levels provide such a high NPV for rapid progression that such patients might forego additional therapy added to single agent ET. Trial registration: NCT00075764 [ABSTRACT FROM AUTHOR]

Overexpression of the thymidine phosphorylase (TP) enzyme induces angiogenesis, which eventually leads to metastasis and tumor growth. The crucial role of TP in cancer development makes it an important target for anticancer drug discovery. Currently, there is only one US-FDA-approved drug, i.e., Lonsurf, a combination of trifluridine and tipiracil, for the treatment of metastatic colorectal cancer. Unfortunately, numerous adverse effects are associated with its use, such as myelosuppression, anemia, and neutropenia. Since the last few decades, the discovery of new, safe, and effective TP inhibitory agents has been rigorously pursued. In the present study, we evaluated a series of previously synthesized dihydropyrimidone derivatives 1–40 for their TP inhibitory potential. Compounds 1, 12, and 33 showed a good activity with IC50 = 314.0 ± 0.90, 303.5 ± 0.40, and 322.6 ± 1.60 µM, respectively. The results of mechanistic studies revealed that compounds 1, 12, and 33 were the non-competitive inhibitors. These compounds were also evaluated for cytotoxicity against 3T3 (mouse fibroblast) cells and were found to be non-cytotoxic. Finally, the molecular docking suggested the plausible mechanism of non-competitive inhibition of TP. The current study thus identifies some dihydropyrimidone derivatives as potential inhibitors of TP, which can be further optimized as leads for cancer treatment. [ABSTRACT FROM AUTHOR]

Tritium is found in the environment under three forms: free in the water, gaseous, and bound to organic matter. Once internalized in living organisms, it can be found in two forms: tissue free water tritium (TFWT) and organically bound tritium (OBT). This study aims to better understand OBT internalization in living organisms and to show the complementarity between experimental procedures and microdosimetry simulations that have often been used to obtain more information on imparted energy to cell nuclei. To do so, tritiated thymidine, an organic form of tritium, was chosen and zebrafish embryos [3.5 h post fertilization (hpf)] were exposed to a range of activity concentrations (2.21 × 103 to 5.95 × 105 Bq/mL). First, individual zebrafish embryos were sampled after different exposure times (1 to 96 h) to qualify the internalization kinetics. Then, the barrier role of the chorion was assessed after 2 days of exposure. Lastly, individual zebrafish embryos were sampled after 1 and 4 days of exposure to measure the internalization in the whole fish and its DNA, but also to highlight a possible link between the internal dose rate and the external activity concentration. Microdosimetry simulations were also made to quantify the imparted energy that could occur in the zebrafish cells after exposure to tritium. Results showed that when bound to thymidine, tritium rapidly incorporates in zebrafish early life stages, with the internalization being almost complete after 24 h. Results also showed that while the chorion acted as a barrier to prevent thymidine from entering the embryos, significant levels could still be measured in the whole organisms as well as in DNA. This study also highlighted that when the external activity concentration increased, the internal dose rate increased as well, following a sigmoidal trend. Microdosimetry simulations highlighted that the size and shape of the cell matters, and that the smallest cells seem to be at the greater risk, with only low-energy electrons inducing energy depositions. A linear fit was also found between the mean energy deposited and the logarithm of the radius of the cell, thus showing that the quantity of deposited energy is proportional to the radius of the cell. While this study highlighted important internalization pattern, it will also be used as the starting point of a study focusing on the toxic effects of tritiated thymidine on zebrafish in its early life stages. [ABSTRACT FROM AUTHOR]

Mass spectrometry and tandem MS (MS/MS) have been widely employed for the identification and quantification of damaged nucleosides in DNA, including those induced by alkylating agents. Upon collisional activation, protonated ions of alkylated nucleosides frequently undergo facile neutral loss of a 2-deoxyribose in MS/MS, and further cleavage of the resulting protonated nucleobases in MS3 can sometimes be employed for differentiating regioisomeric alkylated DNA lesions. Herein, we investigated systematically the collision-induced dissociation (CID) of the protonated ions of O4-alkylthymidine (O4-alkyldT), O2-alkyldT, O6-alkyl-2-deoxyguanosine (O6-alkyldG), and N2-alkyldG through MS3 analysis. The MS3 of O2- and O4-MedT exhibit different fragmentation patterns from each other and from other O2- and O4-alkyldT adducts carrying larger alkyl groups. Meanwhile, elimination of alkene via a six-membered ring transition state is the dominant fragmentation pathway for O2-alkyldT, O4-alkyldT, and O6-alkyldG adducts carrying larger alkyl groups, whereas O6-MedG mainly undergoes elimination of ammonia. The breakdown of N2-alkyldG is substantially influenced by the structure of the alkyl group, where the relative ease in eliminating ammonia and alkene is modulated by the chain length and branching of the alkyl groups. We also rationalize our observations with density functional theory (DFT) calculations.

The gut microbiota metabolizes drugs and alters their efficacy and toxicity. Diet alters drugs, the metabolism of the microbiota, and the host. However, whether diet-triggered metabolic changes in the microbiota can alter drug responses in the host has been largely unexplored. Here we show that dietary thymidine and serine enhance 5-fluoro 2'deoxyuridine (FUdR) toxicity in C. elegans through different microbial mechanisms. Thymidine promotes microbial conversion of the prodrug FUdR into toxic 5-fluorouridine-5'-monophosphate (FUMP), leading to enhanced host death associated with mitochondrial RNA and DNA depletion, and lethal activation of autophagy. By contrast, serine does not alter FUdR metabolism. Instead, serine alters E. coli's 1C-metabolism, reduces the provision of nucleotides to the host, and exacerbates DNA toxicity and host death without mitochondrial RNA or DNA depletion; moreover, autophagy promotes survival in this condition. This work implies that diet-microbe interactions can alter the host response to drugs without altering the drug or the host.

Introduction: The prognosis for glioblastoma multiforme (GBM), a malignant brain tumor, is poor despite recent advancements in treatments. Suicide gene therapy is a therapeutic strategy for cancer that requires a gene to encode a prodrug-activating enzyme which is then transduced into a vector, such as mesenchymal stem cells (MSCs). The vector is then injected into the tumor tissue and exerts its antitumor effects. Case presentation: A 37-year-old man presented to our department with two evident foci of glioblastoma multiforme at the left frontal and left parietal lobes. The patient received an injection of bone marrow-derived MSCs delivering the herpes simplex virus thymidine kinase (HSV-tk) gene to the frontal focus of the tumor, followed by ganciclovir administration as a prodrug for 14 days. For follow-up, the patient was periodically assessed using magnetic resonance imaging (MRI). The growth and recurrence patterns of the foci were assessed. After the injection on 09 February 2019, the patient’s follow-up appointment on 19 December 2019 MRI revealed a recurrence of parietal focus. However, the frontal focus had a slight and unremarkable enhancement. On the last follow-up (18 March 2020), the left frontal focus had no prominent recurrence; however, the size of the left parietal focus increased and extended to the contralateral hemisphere through the corpus callosum. Eventually, the patient passed away on 16 July 2020 (progression-free survival (PFS) = 293 days, overall survival (OS) = 513 days). Conclusion: The gliomatous focus (frontal) treated with bone marrow-derived MSCs carrying the HSV-TK gene had a different pattern of growth and recurrence compared with the non-treated one (parietal). [ABSTRACT FROM AUTHOR]

Serum thymidine kinase 1 protein (STK1p) concentration has been used successfully as a reliable proliferating serum biomarker in early tumour discovery and clinical settings. It is detected by an enhanced chemiluminescence (ECL) dot blot assay with the biotin-streptavidin (BSA) platform (a gold standard) based on chicken anti-human thymidine kinase 1 IgY polyclonal antibody (hTK1-IgY-pAb). However, ECL dot blotting is a semiautomatic method that has been limited to large-scale applications due to the differences among batches of antibodies from individual hens, and the skill level of operation technicians sometimes results in unstable STK1p values. Therefore, a highly stable recombinant chicken full-length IgY monoclonal antibody in combination with a fully automated sandwich biotin-streptavidin (sandwich-BSA) platform was developed. Hens were immunized with 31-peptide, a key sequence of human TK1 (hTK1), before constructing an immune phage display scFv library. Finally, a recombinant full-length IgY monoclonal antibody (hTK1-IgY-rmAb#5) with high-affinity binding with human recombinant TK1 (rhTK1) (3.95 × 10 − 10 mol/L), high sensitivity with hTK1 calibrators (slope of linear curve: 89.98), and high specificity with low/elevated STK1p (r ≈ 0.92 -0.963) was identified. hTK1-IgY-rmAb#5 showed a specific immune response with thymidine kinase 1 (TK1) in TK1-positive/negative cell lysates by Western blotting and immunohistochemistry (IHC) in normal and cancer tissues. In particular, the detection of TK1 serum samples from health centres showed a high coincidence rate (r = 0.988 , n = 90) between hTK1-IgY-rmAb#5 and hTK1-IgY-pAb and between the semiautomatic ECL dot blot BSA platform and the novel automatic chemiluminescence sandwich-BSA platform (r = 0.857 , n = 292). hTK1-IgY-rmAb#5 is stable and highly sensitive for detecting the lowest STK1p value at 0.01 pmol/L (pM). The accuracy is high (SD < 2.5 %) between different batches. It is easy to use the novel hTK1-IgY-rmAb#5 on a new automatic chemiluminescence sandwich-BSA platform. It will be beneficial for large-scale health screenings. [ABSTRACT FROM AUTHOR]

Thymidine kinase 1 (TK1) is an intracellular enzyme involved in DNA-precursor synthesis. Increased serum TK1 levels are used as a biomarker in various malignancies. We combined serum TK1 with PSA and evaluated its capacity to predict overall survival (OS) in 175 men with prostate cancer (PCa), detected by screening in 1988–1989 (n = 52) and during follow-up (median 22.6 years) (n = 123). TK1 was measured in frozen serum, age was stratified into four groups, and dates of PCa diagnosis and dates of death were obtained from Swedish population-based registries. The median concentration of TK1 and PSA was 0.25 and 3.8 ng/ml. TK1 was an independent variable of OS. In the multivariate analysis, PSA was not statistically significant in combination with age whereas the significance remained for TK1 + PSA. Measured once, TK1 + PSA predicted a difference of up to 10 years (depending on patient subgroup) in OS at a median of 9 years before PCa diagnosis. The TK1 concentration in 193 controls without malignancies did not differ from that of the PCa patients, hence TK1 was likely not released from incidental PCa. Thus, TK1 in the blood circulation may indicate the release of TK1 from sources other than cancers, nonetheless associated with OS. [ABSTRACT FROM AUTHOR]