RESUMO
OBJECTIVE: Thymidine-dependent small-colony variants (TD-SCVs) of Staphylococcus aureus are being isolated with increasing frequency from patients with cystic fibrosis (CF). The aim of this study was to evaluate the relationship between TD-SCV isolation and pulmonary function in patients with CF, as well as to determine whether the emergence of TD-SCVs was associated with trimethoprim-sulfamethoxazole (TMP-SMX) use and with coinfection with other microorganisms. METHODS: This was a retrospective case-control study including patients with CF who visited the Clinical Hospital Complex of the Federal University of Paraná, in Curitiba, Brazil, between 2013 and 2022. Demographic, clinical, and spirometric data, as well as information on TD-SCVs and other isolated microorganisms, were collected from the medical records of patients with CF and TD-SCVs (TD-SCV group; n = 32) and compared with those of a matched group of patients with CF without TD-SCVs (control group; n = 64). RESULTS: Isolation of TD-SCVs was positively associated with TMP-SMX use (p = 0.009), hospitalization (p < 0.001), and impaired pulmonary function (p = 0.04). CONCLUSIONS: The use of TMP-SMX seems to contribute to the emergence of TD-SCVs, the isolation of which was directly associated with worse pulmonary function in our sample.
Assuntos
Fibrose Cística , Infecções Estafilocócicas , Staphylococcus aureus , Humanos , Fibrose Cística/microbiologia , Fibrose Cística/fisiopatologia , Estudos Retrospectivos , Masculino , Feminino , Estudos de Casos e Controles , Staphylococcus aureus/efeitos dos fármacos , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/fisiopatologia , Adulto , Adulto Jovem , Adolescente , Timidina/análogos & derivados , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Combinação Trimetoprima e Sulfametoxazol/farmacologia , Pulmão/fisiopatologia , Pulmão/microbiologia , Pulmão/efeitos dos fármacos , Antibacterianos/uso terapêutico , Antibacterianos/farmacologia , Criança , Brasil , Testes de Função RespiratóriaRESUMO
Irradiation of the major conformation of duplex DNA found in cells (B form) produces cyclobutane pyrimidine dimers (CPDs) from adjacent pyrimidines in a head-to-head orientation (syn) with the C5 substituents in a cis stereochemistry. These CPDs have crucial implications in skin cancer. Irradiation of G-quadruplexes and other non-B DNA conformations in vitro produces, however, CPDs between nonadjacent pyrimidines in nearby loops with syn and head-to-tail orientations (anti) with both cis and trans stereochemistry to yield a mixture of six possible isomers of the T=T dimer. This outcome is further complicated by formation of mixtures of nonadjacent CPDs of C=T, T=C, and C=C, and successful analysis depends on development of specific and sensitive methods. Toward meeting this need, we investigated whether ion mobility mass spectrometry (IMMS) and MS/MS can distinguish the cis,syn and trans,anti T=T CPDs. Ion mobility can afford baseline separation and give relative mobilities that are in accord with predicted cross sections. Complementing this ability to distinguish isomers is MS/MS collisional activation where fragmentation also distinguishes the two isomers and confirms conclusions drawn from ion mobility analysis. The observations offer early support that ion mobility and MS/MS can enable the distinction of DNA photoproduct isomers.
Assuntos
Espectrometria de Mobilidade Iônica , Dímeros de Pirimidina , Espectrometria de Massas em Tandem , Espectrometria de Massas em Tandem/métodos , Dímeros de Pirimidina/química , Dímeros de Pirimidina/análise , Isomerismo , Espectrometria de Mobilidade Iônica/métodos , DNA/química , Ciclobutanos/química , Timidina/químicaRESUMO
Stem and progenitor cells hold great promise for regenerative medicine and gene therapy approaches. However, transplantation of living cells entails a fundamental risk of unwanted growth, potentially exacerbated by CRISPR-Cas9 or other genetic manipulations. Here, we describe a safety system to control cell proliferation while allowing robust and efficient cell manufacture, without any added genetic elements. Inactivating TYMS, a key nucleotide metabolism enzyme, in several cell lines resulted in cells that proliferate only when supplemented with exogenous thymidine. Under supplementation, TYMS-/--pluripotent stem cells proliferate, produce teratomas, and successfully differentiate into potentially therapeutic cell types such as pancreatic ß cells. Our results suggest that supplementation with exogenous thymidine affects stem cell proliferation, but not the function of stem cell-derived cells. After differentiation, postmitotic cells do not require thymidine in vitro or in vivo, as shown by the production of functional human insulin in mice up to 5 months after implantation of stem cell-derived pancreatic tissue.
Assuntos
Diferenciação Celular , Proliferação de Células , Timidina , Timidilato Sintase , Humanos , Animais , Camundongos , Timidina/metabolismo , Timidilato Sintase/genética , Timidilato Sintase/metabolismo , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/citologia , Terapia Baseada em Transplante de Células e Tecidos/métodos , Linhagem Celular , Células-Tronco Pluripotentes/metabolismo , Células-Tronco Pluripotentes/citologia , Sistemas CRISPR-CasRESUMO
The tumor-suppressor p53 is commonly inactivated in colorectal cancer and pancreatic ductal adenocarcinoma, but existing treatment options for p53-mutant (p53Mut) cancer are largely ineffective. Here, we report a therapeutic strategy for p53Mut tumors based on abnormalities in the DNA repair response. Investigation of DNA repair upon challenge with thymidine analogs reveals a dysregulation in DNA repair response in p53Mut cells that leads to accumulation of DNA breaks. Thymidine analogs do not interrupt DNA synthesis but induce DNA repair that involves a p53-dependent checkpoint. Inhibitors of poly(ADP-ribose) polymerase (PARPis) markedly enhance DNA double-strand breaks and cell death induced by thymidine analogs in p53Mut cells, whereas p53 wild-type cells respond with p53-dependent inhibition of the cell cycle. Combinations of trifluorothymidine and PARPi agents demonstrate superior anti-neoplastic activity in p53Mut cancer models. These findings support a two-drug combination strategy to improve outcomes for patients with p53Mut cancer.
Assuntos
Neoplasias Colorretais , Neoplasias Pancreáticas , Humanos , Proteína Supressora de Tumor p53/genética , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Reparo do DNA , Poli(ADP-Ribose) Polimerases/genética , Poli(ADP-Ribose) Polimerases/metabolismo , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , DNA/uso terapêutico , Timidina/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genéticaRESUMO
5-Fluorouracil is now routinely used in chemo- and radiotherapy. Incorporated within DNA, the molecule is bound to the sugar backbone, forming the 5-fluorouridine sub-unit investigated in the present work. For the clinical usage of the latter, no information exists on the mechanisms that control the radiosensitizing effect at the molecular level. As low energy (< 12 eV) electrons are abundantly produced along the radiation tracks during cancer treatment using beams of high energy particles, we study how these ballistic secondary electrons damage the sensitizing molecule. The salient result from our study shows that the N-glycosidic bonds are principally affected with a cross-section of approximately two orders of magnitude higher than the canonical thymidine, reflecting to some degree the surviving factor of radiation-treated carcinoma cells with and without 5-fluorouracil incorporation. This result may help in the comprehension of the radiosensitizing effect of the fluoro-substituted thymidine in DNA.
Assuntos
Elétrons , Radiossensibilizantes , Uridina/análogos & derivados , DNA/química , Radiossensibilizantes/química , Dano ao DNA , Timidina , FluoruracilaRESUMO
PURPOSE: We investigated the potential of baseline 4'-[methyl- 11 C]-thiothymidine ([ 11 C]4DST) PET for predicting loco-regional control of head and neck squamous cell carcinoma (HNSCC). METHODS: A retrospective analysis was performed using volumetric parameters, such as SUVmax, proliferative tumor volume (PTV), and total lesion proliferation (TLP), of pretreatment [ 11 C]4DST PET for 91 patients with HNSCC with primary lesions in the oral cavity, hypopharynx, supraglottis, and oropharynx, which included p16-negative patients. PTV and TLP were calculated for primary lesions and metastatic lymph nodes combined. We examined the association among the parameters and relapse-free survival and whether case selection focused on biological characteristics improved the accuracy of prognosis prediction. RESULTS: The area under the curves (AUCs) using PTV and TLP were high for the oropharyngeal/hypopharyngeal/supraglottis groups (0.91 and 0.87, respectively), whereas that of SUVmax was 0.66 ( Pâ <â 0.01). On the other hand, the oral group had lower AUCs for PTV and TLP (0.72 and 0.77, respectively). When all cases were examined, the AUCs using PTV and TLP were 0.84 and 0.83, respectively. CONCLUSION: Baseline [ 11 C]4DST PET/CT volume-based parameters can provide important prognostic information with p16-negative oropharyngeal, hypopharyngeal, and supraglottic cancer patients.
Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Orofaríngeas , Tomografia por Emissão de Pósitrons , Carcinoma de Células Escamosas de Cabeça e Pescoço , Humanos , Radioisótopos de Carbono , Carcinoma de Células Escamosas/diagnóstico por imagem , Carcinoma de Células Escamosas/patologia , Fluordesoxiglucose F18 , Neoplasias de Cabeça e Pescoço/diagnóstico por imagem , Hipofaringe/diagnóstico por imagem , Hipofaringe/patologia , Recidiva Local de Neoplasia , Neoplasias Orofaríngeas/diagnóstico por imagem , Neoplasias Orofaríngeas/patologia , Orofaringe/diagnóstico por imagem , Orofaringe/patologia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Tomografia por Emissão de Pósitrons/métodos , Prognóstico , Estudos Retrospectivos , Carcinoma de Células Escamosas de Cabeça e Pescoço/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Timidina/química , Timidina/farmacologiaRESUMO
IMPORTANCE: New antibacterial agents are urgently needed to counter increasingly resistant bacteria. One approach to this problem is library screening for new antibacterial agents. Library screening efforts can be improved by increasing the information content of the screening effort. In this study, we screened the National Cancer Institute diversity set V against methicillin-resistant Staphylococcus aureus (MRSA) with several enhancements. One of these is to screen the library before and after microsomal metabolism as means to identify potential active metabolites. A second enhancement is to screen the library in the absence and presence of sub-minimum inhibitory concentration levels of another antibiotic, such as cefoxitin in this study. This identified four agents with synergistic activity with cefoxitin out of 16 agents with good MRSA activity alone. Finally, active agents from this effort were counter-screened in the presence of thymidine, which quickly identified three folate/thymidine biosynthesis inhibitors, and also screened for bactericidal vs bacteriostatic activity.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Estados Unidos , Cefoxitina/farmacologia , Cromatografia Líquida , National Cancer Institute (U.S.) , Espectrometria de Massas em Tandem , Antibacterianos/farmacologia , Testes de Sensibilidade Microbiana , TimidinaRESUMO
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.
Assuntos
Antineoplásicos , Neoplasias de Cabeça e Pescoço , Humanos , Simulação de Acoplamento Molecular , Antineoplásicos/química , Timidina/farmacologia , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Proliferação de Células , Estrutura Molecular , Apoptose , Relação Estrutura-AtividadeRESUMO
OBJECTIVES: We recently designed a series of cationic deoxythymidine-based amphiphiles that mimic the cationic amphipathic structure of antimicrobial peptides (AMPs). Among these amphiphiles, ADG-2e and ADL-3e displayed the highest selectivity against bacterial cells. In this study, ADG-2e and ADL-3e were evaluated for their potential as novel classes of antimicrobial, antibiofilm, and anti-inflammatory agents. METHODS: Minimum inhibitory concentrations of ADG-2e and ADL-3e against bacteria were determined using the broth microdilution method. Proteolytic resistance against pepsin, trypsin, α-chymotrypsin, and proteinase K was determined by radial diffusion and HPLC analysis. Biofilm activity was investigated using the broth microdilution and confocal microscopy. The antimicrobial mechanism was investigated by membrane depolarization, cell membrane integrity analysis, scanning electron microscopy (SEM), genomic DNA influence and genomic DNA binding assay. Synergistic activity was evaluated using checkerboard method. Anti-inflammatory activity was investigated using ELISA and RT-PCR. RESULTS: ADG-2e and ADL-3e showed good resistance to physiological salts and human serum, and a low incidence of drug resistance. Moreover, they exhibit proteolytic resistance against pepsin, trypsin, α-chymotrypsin, and proteinase K. ADG-2e and ADL-3e were found to kill bacteria by an intracellular target mechanism and bacterial cell membrane-disrupting mechanism, respectively. Furthermore, ADG-2e and ADL-3e showed effective synergistic effects when combined with several conventional antibiotics against methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Pseudomonas aeruginosa (MDRPA). Importantly, ADG-2e and ADL-3e not only suppressed MDRPA biofilm formation but also effectively eradicated mature MDRPA biofilms. Furthermore, ADG-2e and ADL-3e drastically decreased tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) gene expression and protein secretion in lipopolysaccharide (LPS)-stimulated macrophages, implying potent anti-inflammatory activity in LPS-induced inflammation. CONCLUSION: Our findings suggest that ADG-2e and ADL-3e could be further developed as novel antimicrobial, antibiofilm, and anti-inflammatory agents to combat bacterial infections.
Assuntos
Anti-Infecciosos , Staphylococcus aureus Resistente à Meticilina , Humanos , Peptídeos Catiônicos Antimicrobianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Lipopolissacarídeos , Endopeptidase K/farmacologia , Pepsina A/farmacologia , Tripsina/farmacologia , Anti-Infecciosos/farmacologia , Anti-Infecciosos/química , Antibacterianos/farmacologia , Antibacterianos/química , Anti-Inflamatórios/farmacologia , Bactérias , Biofilmes , Timidina/farmacologia , Testes de Sensibilidade MicrobianaRESUMO
DNA alkylation is caused by long-term exposure of cells to the environmental and endogenous alkylating agents, which can also lead to DNA mutations and therefore trigger some cancers. Since O4-methylthymidine (O4-meT), mismatched with guanine (G), is the most common but not easily repaired alkylated nucleoside, monitoring O4-meT can help to effectively reduce the occurrence of carcinogenesis. In this work, the modified G-analogues are selected as the fluorescence probe to monitor the existence of O4-meT according to its pairing characteristics. The photo-physical properties of considered G-analogues formed by ring expansion or addition of fluorophores were studied in detail. It is found that, compared with natural G, the absorption peaks of these fluorescence analogues are red-shifted (>55 nm) and the luminescence is enhanced by π-conjugation. Especially, the xG has a large Stokes shift (65 nm) with fluorescence insensitive to natural cytosine (C) and retains efficient emission after pairing, while it is sensitive to O4-meT and the quenching phenomenon occurs due to the excited state intermolecular charge transfer. Accordingly, the xG can be used as a fluorescent probe to identify the O4-meT in solution. In addition, the direct use of deoxyguanine fluorescent analogue for monitoring O4-meT was evaluated by the effects of ligating deoxyribose on absorption and fluorescence emission.
Assuntos
DNA , Nucleosídeos , Fluorescência , TimidinaRESUMO
The ability to monitor lymphocyte responses is critical for developing our understanding of the immune response in humans. In the current clinical setting, relying on the metabolic incorporation of [3H] thymidine into cellular DNA via a lymphocyte proliferation test (LPT) is the only method that is routinely performed to determine cell proliferation. However, techniques that measure DNA synthesis with a radioactive material such as [3H] thymidine are intrinsically more sensitive to the different stages of the cell cycle, which could lead to over-analyses and the subsequent inaccurate interpretation of the information provided. With cell proliferation assays, the output should preferably provide a direct and accurate measurement of the number of actively dividing cells, regardless of the stimuli properties or length of exposure. In fact, an ideal technique should have the capacity to measure lymphocyte responses on both a quantitative level, i.e., cumulative magnitude of lymphoproliferative response, and a qualitative level, i.e., phenotypical and functional characterization of stimulated immune cells. There are many LPT alternatives currently available to measure various aspects of cell proliferation. Of the nine techniques discussed, we noted that the majority of these LPT alternatives measure lymphocyte proliferation using flow cytometry. Across some of these alternatives, the covalent labelling of cells with a high fluorescence intensity and low variance with minimal cell toxicity while maximizing the number of detectable cell divisions or magnitude of proliferation was achieved. Herein, we review the performance of these different LPT alternatives and address their compatibility with the [3H] thymidine LPT so as to identify the "best" alternative to the [3H] thymidine LPT.
Assuntos
DNA , Linfócitos , Humanos , Linfócitos/metabolismo , Divisão Celular , Proliferação de Células , Timidina/metabolismoRESUMO
Analysis of T lymphocyte proliferation and activation after antigenic or mitogenic stimulation is a vital parameter used in the diagnosis of various immuno-deficiencies and during the monitoring of treatment responses. Most applied techniques are based on the incorporation of tritiated thymidine (3H-TdR) or ELISPOT analysis, both rely on rather time-consuming/-intensive ex vivo protocols or encompass inherent drawbacks such as the inability to distinguish specific cell populations (3H-TdR, ELISPOT) or focus on a single cytokine (ELISPOT). Here we aimed at characterizing the rapid expression of intracellular CD154 (CD40L) as a marker for rare antigen-specific CD4+ T cells in pemphigus vulgaris (PV). Upon stimulation with human desmoglein (Dsg) 3, the major autoantigen in PV, the expression of CD154 was significantly increased in PV patients compared to healthy controls (HC) and correlated with anti-Dsg3 IgG titers. Patients with active disease showed higher numbers of Dsg3-reactive CD4+ T cells in CXCR5+ T follicular helper cells. In remittent PV and HC, CXCR5+CD4+ T cells remained largely unaffected by Dsg3. IL-17 and IL-21 expression were significantly induced only in CD154+CD4+ T cells from PV patients, lending themselves as potential novel treatment targets. Additionally, stimulation with immunodominant Dsg3-derived epitopes strongly induced a CD4+ T cell response via CD40-CD154 interaction similar to the human Dsg3 protein. We here established a rapid ex vivo assay allowing the detection of Dsg3-reactive CD4+ T cells from activated systemically available PBMCs, which further supports the crucial concept of antigen-specific T cells in the pathogenesis of PV.
Assuntos
Pênfigo , Autoantígenos , Ligante de CD40/metabolismo , Citocinas/metabolismo , Epitopos , Humanos , Imunoglobulina G/metabolismo , Interleucina-17/metabolismo , Subpopulações de Linfócitos T , Timidina/metabolismoRESUMO
OBJECTIVE: Elevated myeloid-derived suppressor cells (MDSCs) in many malignancies are associated with the increased risk for metastases and poor prognosis. Therefore, a mouse model of intraocular melanoma was established to explore how MDSCs influence liver metastases. METHODS: In this study, murine B16LS melanoma cells were transplanted into the posterior compartment (PC) of the eye of C57BL/6 mice. Leucocytes from the liver of naive mice and mice bearing melanoma liver metastasis were isolated using isotonic Percoll centrifugation, examined by flow cytometry for their expression of Gr1, CD11b, F4/80, RAE-1, and Mult-1, and further isolated for MDSCs and natural killer (NK) cells. The effects of MDSCs on NK cells were tested by coculturing and assessing the ability of NK cells to produce interferon-gamma (IFN-γ) by ELISA and NK cell cytotoxicity by 3H-thymidine incorporation assay. The impact of IFN-γ on liver metastases was examined via selectively depleting IFN-γ in vivo. RESULTS: The results showed that mice with liver metastases had increased levels of CD11b+Gr1+F4/80+ as well as CD11b+Gr1+F4/80- MDSCs. MDSCs significantly enhanced the generation of IFN-γ together with the cytotoxicity of the NK cells. Furthermore, these effects were cell-cell contact-dependent. Although IFN-γ was not of a toxic nature to the melanoma cells, it profoundly inhibited B16LS cell proliferation. Depleting IFN-γ in vivo led to increased liver metastases. CONCLUSION: All these findings first revealed that MDSCs accumulated in liver metastasis of intraocular melanoma could activate the NK cells to produce an effective anti-tumor immune response. Thus, the MDSCs' performance in different tumor models would need more investigation to boost current immunotherapy modalities.
Assuntos
Neoplasias Hepáticas , Melanoma , Células Supressoras Mieloides , Camundongos , Animais , Células Supressoras Mieloides/metabolismo , Células Supressoras Mieloides/patologia , Interferon gama/genética , Interferon gama/metabolismo , Modelos Animais de Doenças , Camundongos Endogâmicos C57BL , Melanoma/metabolismo , Melanoma/patologia , Células Matadoras Naturais , Neoplasias Hepáticas/patologia , Timidina/metabolismoRESUMO
Thymidine phosphorylase (TP) is an important enzyme for the synthesis and decomposition of pyrimidine, which can specifically catalyze the reversible phosphorolysis of thymidine to thymine and 2-deoxy-α-D-ribose-1-phosphate in the body. TP is highly expressed in many solid tumor tissues and can induce angiogenesis and anti-apoptotic effect, as well as tumor growth and metastasis. Therefore, TP inhibitors play a major role in the treatment. In recent years, a large number of synthetic TP inhibitors have been widely reported. In this article, the research progress of synthetic TP inhibitors was reviewed, including inhibitory activity, cytotoxicity, structure-activity relationship (SAR), inhibitory kinetics, mechanism of interaction and molecular docking. In our reviewed inhibitors, pyrimidine derivatives account for about a half, but it is a lack for research on other biological activities of pyrimidine derivatives and further exploration of the inhibitory mechanism of excellent inhibitors. Meanwhile, application of radiolabeled inhibitors to assess TP expression in tumors and prognosis of cancer chemotherapy in vivo is rarely reported. In addition, the study on the synergistic anticancer activity of TP inhibitors in combination with other anticancer drugs is less. Therefore, it is valuable to look forward to developing more and more potent TP inhibitors and applying them in the clinical treatment of cancer in the future.
Assuntos
Antineoplásicos , Neoplasias , Humanos , Timidina Fosforilase/metabolismo , Timidina Fosforilase/uso terapêutico , Timina , Simulação de Acoplamento Molecular , Ribose/uso terapêutico , Neoplasias/patologia , Timidina/farmacologia , Timidina/uso terapêutico , Timidina/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Pirimidinas/uso terapêutico , Fosfatos , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêuticoRESUMO
Thymidine Kinase 1 (TK1) plays an important role in DNA precursor synthesis and serum TK1 activity has been used as a biomarker for prognosis and therapy monitoring of different malignancies. AroCell has developed a dual monoclonal antibody ELISA for determination of TK1 protein in clinical samples. The purpose of the study is to validate the ELISA analytically in relation to the gold standard, [3H]-deoxythymidine (dThd) phosphorylation assay for TK1 activity using sera from patients with different malignancies. The colorimetric TK 210 ELISA was validated analytically by assessment of precision, linearity, interfering substances, and stability. For the clinical validation, serum samples from patients with hematological malignancies (n = 100), breast cancer (n = 56), prostate cancer (n = 70) and blood donors (n = 159) were analyzed using TK 210 ELISA and TK1 activity by [3H]-deoxythymidine (dThd) phosphorylation assay. The sandwich TK 210 ELISA was highly specific for TK1 protein having a detection limit of 0.12 ng/mL, with a functional sensitivity of 0.25 ng/mL. Within-run CVs ranged from 5.5% to 10% and between-run CVs ranged from 5% to 15%. The ratio of observed to expected dilutional parallelism of 5 serum samples was in the range of 80-120%. Samples exhibited stability through four freeze/thaw cycles and 5 days at 4°C. Further, the ROC curve analysis showed that TK 210 ELISA and [3H]-dThd phosphorylation assay had similar sensitivity (62% vs 59%) in hematological malignancies. However, in the case of breast and prostate cancer sera, TK 210 ELISA had higher sensitivity (59% and 44%) compared to [3H]-dThd phosphorylation assay (47% and 25%) at a specificity of 98%. These data demonstrate that the dual monoclonal antibody based AroCell TK 210 ELISA is a robust, accurate and precise tool for measuring TK1 protein in different malignancies that can improve the clinical applications of TK1 as a biomarker in cancer management.
Assuntos
Neoplasias da Mama , Neoplasias Hematológicas , Neoplasias da Próstata , Anticorpos Monoclonais , Biomarcadores Tumorais , DNA , Ensaio de Imunoadsorção Enzimática , Neoplasias Hematológicas/patologia , Humanos , Masculino , Timidina , Timidina Quinase/genéticaRESUMO
BACKGROUND/AIM: Solar ultraviolet radiation (UVR) is a carcinogen and irradiation of the skin results in DNA damage. Cyclobutane pyrimidine dimers (CPDs), including thymidine dimers, are among the most frequent forms of DNA damage. When CPDs are formed, the nucleotide excision repair system is activated and CPDs are excreted in the urine. Here, we developed a mass spectrometry-based method to quantify thymidine dimers in the urine and tested the method on a small group of volunteers after whole-body UVR exposure. PATIENTS AND METHODS: Years of research resulted in a method based on the "dilute-and-shoot" principle and ultra-performance liquid chromatography (UPLC) coupled to mass spectrometry. The whole body of each of eight healthy volunteers was exposed to 1.5-2.0 standard erythema doses (SEDs) of UVR for 3 consecutive days. Morning urine was collected on Day 1 (before irradiation) and on the following 7-9 days. Prior to analysis, sample preparation consisted of a simple dilution. A tandem quadrupole mass spectrometer coupled to UPLC was used for quantitative analysis in the multiple reaction monitoring mode. RESULTS: After 3 consecutive days of 1.5-2 SEDs, the highest level of thymidine dimer excretion occurred on Day 6 (0.7 ng/ml urine). Compared with baseline, significantly more thymidine dimers were excreted every day until Day 8 (p<0.016). Our method quantifies thymidine dimers that are excreted as dimers (i.e., not degraded further) after nucleotide excision repair. CONCLUSION: This is the first published mass spectrometry-based method for quantifying thymidine dimers in the urine after whole-body UVR exposure.
Assuntos
Dímeros de Pirimidina , Raios Ultravioleta , Carcinógenos , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Dano ao DNA , Reparo do DNA , Humanos , Dímeros de Pirimidina/efeitos da radiação , Dímeros de Pirimidina/urina , Espectrometria de Massas em Tandem , Timidina , Raios Ultravioleta/efeitos adversos , VoluntáriosRESUMO
ATR kinase is a central regulator of the DNA damage response (DDR) and cell cycle checkpoints. ATR kinase inhibitors (ATRi's) combine with radiation to generate CD8+ T cell-dependent responses in mouse models of cancer. We show that ATRi's induce cyclin-dependent kinase 1 (CDK1)-dependent origin firing across active replicons in CD8+ T cells activated ex vivo while simultaneously decreasing the activity of rate-limiting enzymes for nucleotide biosynthesis. These pleiotropic effects of ATRi induce deoxyuridine (dU) contamination in genomic DNA, R loops, RNA-DNA polymerase collisions, and interferon-α/ß (IFN-α/ß). Remarkably, thymidine rescues ATRi-induced dU contamination and partially rescues death and IFN-α/ß expression in proliferating CD8+ T cells. Thymidine also partially rescues ATRi-induced cancer cell death. We propose that ATRi-induced dU contamination contributes to dose-limiting leukocytopenia and inflammation in the clinic and CD8+ T cell-dependent anti-tumor responses in mouse models. We conclude that ATR is essential to limit dU contamination in genomic DNA and IFN-α/ß expression.
Assuntos
Linfócitos T CD8-Positivos , Proteína Quinase CDC2 , Animais , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Proteína Quinase CDC2/metabolismo , Morte Celular , Linhagem Celular Tumoral , DNA , Dano ao DNA , DNA Polimerase Dirigida por DNA/metabolismo , Desoxiuridina , Genômica , Interferon-alfa/metabolismo , Interferon beta , Camundongos , Nucleotídeos/metabolismo , Inibidores de Proteínas Quinases/farmacologia , RNA , Timidina/farmacologiaRESUMO
Inborn errors of pyrimidine metabolism result from deficiencies in pyrimidine de novo synthesis, degradation, and salvage pathways. Enzymatic deficiencies in pyrimidine catabolism lead to mitochondrial neurogastrointestinal encephalopathy (MNGIE), pyrimidinuria, dihydropyrimidinuria, ureidopropionic aciduria, and other disorders. While MNGIE presents with gastrointestinal dysmotility, cachexia and leukoencephalopathy, pyrimidinuria, and dihydropyrimidinuria may show symptoms of epilepsy, autism, mental retardation, and dysmorphic features. The application of HPLC-MS/MS facilitates rapid screening of pyrimidine metabolites. Here we describe a sensitive and reliable LC-MS/MS method for quantitative determination of uracil, thymine, thymidine, dihydrouracil, and dihydrothymine in urine that are diagnostic biomarkers of MNGIE, pyrimidinuria, and dihydropyrimidinuria.
Assuntos
Deficiência da Di-Hidropirimidina Desidrogenase , Espectrometria de Massas em Tandem , Biomarcadores , Cromatografia Líquida , Humanos , Pirimidinas , Espectrometria de Massas em Tandem/métodos , Timidina , Timina , UracilaRESUMO
Renal tissue plays a crucial function in maintaining homeostasis, making it vulnerable to xenobiotic toxicity. Pueraria montana has more beneficial potential against the various diseases and has long history used as a traditional Chinese medicine. But its effect against the renal cancer not scrutinize. The goal of this study is to see if Pueraria montana can protect rats from developing kidney tumors caused by diethylnitrosamine (DEN) and ferric nitrite (Fe-NTA). Wistar rats was selected for the current study and DEN (use as an inducer) and Fe-NTA (promoter) for induction the renal cancer. For 22 weeks, the rats were given orally Pueraria montana (12.5, 25, and 50 mg/kg) treatment. At regular intervals, the body weight and food intake were calculated. The rats were macroscopically evaluated for identification of cancer in the renal tissue. The renal tumor makers, renal parameters, antioxidant enzymes, phase I and II enzymes, inflammatory cytokines and mediators were estimated at end of the experimental study. Pueraria montana treated rats displayed the suppression of renal tumors, incidence of the tumors along with suppression of tumor percentage. Pueraria montana treated rats significantly (p < 0.001) increased body weight and suppressed the renal weight and food intake. It also reduced the level of renal tumor marker ornithine decarboxylase (ODC) and [3H] thymidine incorporation along with suppression of renal parameter such as uric acid, blood urea nitrogen (BUN), urea and creatinine. Pueraria montana treatment significantly (p < 0.001) altered the level of phase enzymes and antioxidant. Pueraria montana treatment significantly (p < 0.001) repressed the level of tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6) and improved the level of interleukin-10 (IL-10). Pueraria montana treatment suppressed the level of prostaglandin (PGE2), cyclooxygenase-2 (COX-2), nuclear kappa B factor (NF-κB) and transforming growth factor beta 1 (TGF-ß1). Pueraria montana suppressed the inflammatory necrosis, size the bowman capsules in the renal histopathology. Pueraria montana exhibited the chemoprotective effect via dual mechanism such as suppression of inflammatory reaction and oxidative stress.