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1.
Electrochim Acta ; 3622020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-33087943

RESUMEN

Recently we showed the reduction and oxidation of six natural 2'-deoxynucleosides in the presence of the ambient oxygen using the very broad potential window of a pyrolytic graphite electrode (PGE). Using the same procedure, 2'-deoxynucleoside analogs (dNs) that are parts of an artificially expanded genetic information system (AEGIS) were analyzed. Seven of the eight tested AEGIS dNs provided specific signals (voltammetric redox peaks). These signals, described here for the first time, will be used in future work to analyze DNA built from expanded genetic alphabets, helping to further develop AEGIS technology and its applications. Comparison of the electrochemical behavior of unnatural dNs with the previously documented behaviors of natural dNs also provides insights into the mechanisms of their respective redox processes.

2.
Lancet ; 391(10135): 2128-2139, 2018 05 26.
Artículo en Inglés | MEDLINE | ID: mdl-29754777

RESUMEN

BACKGROUND: The estimation of risk of recurrence for patients with colon carcinoma must be improved. A robust immune score quantification is needed to introduce immune parameters into cancer classification. The aim of the study was to assess the prognostic value of total tumour-infiltrating T-cell counts and cytotoxic tumour-infiltrating T-cells counts with the consensus Immunoscore assay in patients with stage I-III colon cancer. METHODS: An international consortium of 14 centres in 13 countries, led by the Society for Immunotherapy of Cancer, assessed the Immunoscore assay in patients with TNM stage I-III colon cancer. Patients were randomly assigned to a training set, an internal validation set, or an external validation set. Paraffin sections of the colon tumour and invasive margin from each patient were processed by immunohistochemistry, and the densities of CD3+ and cytotoxic CD8+ T cells in the tumour and in the invasive margin were quantified by digital pathology. An Immunoscore for each patient was derived from the mean of four density percentiles. The primary endpoint was to evaluate the prognostic value of the Immunoscore for time to recurrence, defined as time from surgery to disease recurrence. Stratified multivariable Cox models were used to assess the associations between Immunoscore and outcomes, adjusting for potential confounders. Harrell's C-statistics was used to assess model performance. FINDINGS: Tissue samples from 3539 patients were processed, and samples from 2681 patients were included in the analyses after quality controls (700 patients in the training set, 636 patients in the internal validation set, and 1345 patients in the external validation set). The Immunoscore assay showed a high level of reproducibility between observers and centres (r=0·97 for colon tumour; r=0·97 for invasive margin; p<0·0001). In the training set, patients with a high Immunoscore had the lowest risk of recurrence at 5 years (14 [8%] patients with a high Immunoscore vs 65 (19%) patients with an intermediate Immunoscore vs 51 (32%) patients with a low Immunoscore; hazard ratio [HR] for high vs low Immunoscore 0·20, 95% CI 0·10-0·38; p<0·0001). The findings were confirmed in the two validation sets (n=1981). In the stratified Cox multivariable analysis, the Immunoscore association with time to recurrence was independent of patient age, sex, T stage, N stage, microsatellite instability, and existing prognostic factors (p<0·0001). Of 1434 patients with stage II cancer, the difference in risk of recurrence at 5 years was significant (HR for high vs low Immunoscore 0·33, 95% CI 0·21-0·52; p<0·0001), including in Cox multivariable analysis (p<0·0001). Immunoscore had the highest relative contribution to the risk of all clinical parameters, including the American Joint Committee on Cancer and Union for International Cancer Control TNM classification system. INTERPRETATION: The Immunoscore provides a reliable estimate of the risk of recurrence in patients with colon cancer. These results support the implementation of the consensus Immunoscore as a new component of a TNM-Immune classification of cancer. FUNDING: French National Institute of Health and Medical Research, the LabEx Immuno-oncology, the Transcan ERAnet Immunoscore European project, Association pour la Recherche contre le Cancer, CARPEM, AP-HP, Institut National du Cancer, Italian Association for Cancer Research, national grants and the Society for Immunotherapy of Cancer.


Asunto(s)
Neoplasias del Colon/clasificación , Neoplasias del Colon/diagnóstico , Recurrencia Local de Neoplasia/etiología , Adulto , Anciano , Neoplasias del Colon/inmunología , Femenino , Humanos , Linfocitos Infiltrantes de Tumor , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Pronóstico , Modelos de Riesgos Proporcionales , Reproducibilidad de los Resultados
3.
Immunol Invest ; 47(7): 643-653, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29924680

RESUMEN

BACKGROUND: The objective of this study was to investigate serum levels of immunosuppressive cytokines TGF beta 1 and VEGF and count of immune cells in peripheral blood in stage II and III colorectal cancer patients. METHODS: Blood samples were collected from 22 colorectal patients and 25 healthy controls before the start of treatment. All patients were examined by a clinical immunologist to exclude patients with immune disorders and autoimmune diseases. TGF beta 1 and VEGF were measured by ELISA, and anti-tumor cellular immunity cells (CD4, CD8, B cells, NK cells) were measured by flow cytometry. RESULTS: TGF beta 1 and VEGF plasma levels were significantly increased in stage II and III colorectal patients compared with control group (both p < 0.0001). A decrease in the cellular immunity was shown in the absolute numbers of cytotoxic T lymphocytes (CD8+ ; p = 0.0240), helper T lymphocytes (CD4+ ; p = 0.0019), and natural killer cells (CD16 + CD56+; p < 0.0001) in both stage II and stage III patients. On the contrary, B lymphocyte (CD19+) serum levels were increased in colon cancer patients (p < 0.0001) compared to the control group. CONCLUSIONS: Our results show peripheral blood levels of TGF beta and VEGF were significantly increased in colorectal patients and changes in cellular anticancer immunity in comparison to control group. These results will be compared with results from Immunoscore.


Asunto(s)
Adenocarcinoma/inmunología , Linfocitos B/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Neoplasias Colorrectales/inmunología , Células Asesinas Naturales/inmunología , Factor de Crecimiento Transformador beta1/sangre , Factor A de Crecimiento Endotelial Vascular/sangre , Circulación Sanguínea , Femenino , Humanos , Inmunidad Celular , Recuento de Linfocitos , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias
4.
J Cancer Res Clin Oncol ; 150(2): 99, 2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38383923

RESUMEN

PURPOSE: Immune checkpoint inhibitors (ICIs) dramatically changed the prognosis of patients with NSCLC. Unfortunately, a reliable predictive biomarker is still missing. Commonly used biomarkers, such as PD-L1, MSI, or TMB, are not quite accurate in predicting ICI efficacy. METHODS: In this prospective observational cohort study, we investigated the predictive role of erythrocytes, thrombocytes, innate and adaptive immune cells, complement proteins (C3, C4), and cytokines from peripheral blood of 224 patients with stage III/IV NSCLC treated with ICI alone (pembrolizumab, nivolumab, and atezolizumab) or in combination (nivolumab + ipilimumab) with chemotherapy. These values were analyzed for associations with the response to the treatment and survival endpoints. RESULTS: Higher baseline Tregs, MPV, hemoglobin, and lower monocyte levels were associated with favorable PFS and OS. Moreover, increased baseline basophils and lower levels of C3 predicted significantly improved PFS. The levels of the baseline immature granulocytes, C3, and monocytes were significantly associated with the occurrence of partial regression at the first restaging. Multiple studied parameters (n = 9) were related to PFS benefit at the time of first restaging as compared to baseline values. In addition, PFS nonbenefit group showed a decrease in lymphocyte count after three months of therapy. The OS benefit was associated with higher levels of lymphocytes, erythrocytes, hemoglobin, MCV, and MPV, and a lower value of NLR after three months of treatment. CONCLUSION: Our work suggests that parameters from peripheral venous blood may be potential biomarkers in NSCLC patients on ICI. The baseline values of Tregs, C3, monocytes, and MPV are especially recommended for further investigation.


Asunto(s)
Antineoplásicos Inmunológicos , Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Humanos , Nivolumab/uso terapéutico , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Inmunofenotipificación , Estudios Prospectivos , Antineoplásicos Inmunológicos/uso terapéutico , Biomarcadores , Hemoglobinas/uso terapéutico , Antígeno B7-H1
5.
Ther Adv Med Oncol ; 15: 17588359231197957, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37786538

RESUMEN

Mitochondrially targeted anticancer drugs (mitocans) that disrupt the energy-producing systems of cancer are emerging as new potential therapeutics. Mitochondrially targeted tamoxifen (MitoTam), an inhibitor of mitochondrial respiration respiratory complex I, is a first-in-class mitocan that was tested in the phase I/Ib MitoTam-01 trial of patients with metastatic cancer. MitoTam exhibited a manageable safety profile and efficacy; among 37% (14/38) of responders, the efficacy was greatest in patients with metastatic renal cell carcinoma (RCC) with a clinical benefit rate of 83% (5/6) of patients. This can be explained by the preferential accumulation of MitoTam in the kidney tissue in preclinical studies. Here we report the mechanism of action and safety profile of MitoTam in a case series of RCC patients. All six patients were males with a median age of 69 years, who had previously received at least three lines of palliative systemic therapy and suffered progressive disease before starting MitoTam. We recorded stable disease in four, partial response in one, and progressive disease (PD) in one patient. The histological subtype matched clear cell RCC (ccRCC) in the five responders and claro-cellular carcinoma with sarcomatoid features in the non-responder. The number of circulating tumor cells (CTCs) was evaluated longitudinally to monitor disease dynamics. Beside the decreased number of CTCs after MitoTam administration, we observed a significant decrease of the mitochondrial network mass in enriched CTCs. Two patients had long-term clinical responses to MitoTam, of 50 and 36 weeks. Both patients discontinued treatment due to adverse events, not PD. Two patients who completed the trial in November 2019 and May 2020 are still alive without subsequent anticancer therapy. The toxicity of MitoTam increased with the dosage but was manageable. The efficacy of MitoTam in pretreated ccRCC patients is linked to the novel mechanism of action of this first-in-class mitochondrially targeted drug.

6.
EClinicalMedicine ; 57: 101873, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37064512

RESUMEN

Background: Mitochondria present an emerging target for cancer treatment. We have investigated the effect of mitochondrially targeted tamoxifen (MitoTam), a first-in-class anti-cancer agent, in patients with solid metastatic tumours. Methods: MitoTam was tested in an open-label, single-centre (Department of Oncology, General Faculty Hospital, Charles University, Czech Republic), phase I/Ib trial in metastatic patients with various malignancies and terminated oncological therapies. In total, 75 patients were enrolled between May 23, 2018 and July 22, 2020. Phase I evaluated escalating doses of MitoTam in two therapeutic regimens using the 3 + 3 design to establish drug safety and maximum tolerated dose (MTD). In phase Ib, three dosing regimens were applied over 8 and 6 weeks to evaluate long-term toxicity of MitoTam as the primary objective and its anti-cancer effect as a secondary objective. This trial was registered with the European Medicines Agency under EudraCT 2017-004441-25. Findings: In total, 37 patients were enrolled into phase I and 38 into phase Ib. In phase I, the initial application of MitoTam via peripheral vein indicated high risk of thrombophlebitis, which was avoided by central vein administration. The highest dose with acceptable side effects was 5.0 mg/kg. The prevailing adverse effects (AEs) in phase I were neutropenia (30%), anaemia (30%) and fever/hyperthermia (30%), and in phase Ib fever/hyperthermia (58%) together with anaemia (26%) and neutropenia (16%). Serious AEs were mostly related to thromboembolic (TE) complications that affected 5% and 13% of patients in phase I and Ib, respectively. The only statistically significant AE related to MitoTam treatment was anaemia in phase Ib (p = 0.004). Of the tested regimens weekly dosing with 3.0 mg/kg for 6 weeks afforded the best safety profile with almost all being grade 1 (G1) AEs. Altogether, five fatalities occurred during the study, two of them meeting criteria for Suspected Unexpected Serious Adverse Events Reporting (SUSAR) (G4 thrombocytopenia and G5 stroke). MitoTam showed benefit evaluated as clinical benefit rate (CBR) in 37% patients with the largest effect in renal cell carcinoma (RCC) where four out of six patients reached disease stabilisation (SD), one reached partial response (PR) so that in total, five out of six (83%) patients showed CBR. Interpretation: In this study, the MTD was established as 5.0 mg/kg and the recommended dose of MitoTam as 3.0 mg/kg given once per week via central vein with recommended preventive anti-coagulation therapy. The prevailing toxicity included haematological AEs, hyperthermia/fever and TE complications. One fatal stroke and non-fatal G4 thrombocytopenia were recorded. MitoTam showed high efficacy against RCC. Funding: Smart Brain Ltd. Translation: For the Czech translation of the abstract see Supplementary Materials section.

7.
Sci Total Environ ; 900: 165803, 2023 Nov 20.
Artículo en Inglés | MEDLINE | ID: mdl-37499824

RESUMEN

Deposits of fly ash and other coal combustion wastes are common remnants of the energy industry. Despite their environmental risks from heavy metals and trace elements, they have been revealed as refuges for threatened terrestrial biodiversity. Surprisingly, freshwater biodiversity of fly ash sedimentation lagoons remains unknown despite such lack of knowledge strongly limits the efficient restoration of fly ash deposits. We bring the first comprehensive survey of freshwater biodiversity, including nekton, benthos, zooplankton, phytoplankton, and macrophytes, in fly ash lagoons across industrial regions of the Czech Republic. To assess their conservation potential, we compared their biodiversity with abandoned post-mining ponds, the known strongholds of endangered aquatic species in the region with a shortage of natural ponds. Of 28 recorded threatened species, 15 occurred in the studied fly ash lagoons, some of which were less abundant or even absent in the post-mining ponds. These are often species of nutrient-poor, fishless waters with rich vegetation, although some are specialised extremophiles. Species richness and conservation value of most groups in the fly ash lagoons did not significantly differ from the post-mining ponds, except for species richness of benthos, zooplankton, and macrophytes, which were slightly lower in the fly ash lagoons. Although the concentrations of some heavy metals (mainly Se, V, and As) were significantly higher in the fly ash lagoons, they did not significantly affect species richness or conservation value of the local communities. The differences in species composition therefore does not seem to be caused by water chemistry. Altogether, we have shown that fly ash lagoons are refuges for threatened aquatic species, and we thus suggest maintaining water bodies during site restoration after the cessation of fly ash deposition. Based on our analyses of environmental variables, we discuss suitable restoration practices that efficiently combine biodiversity protection and environmental risk reduction.


Asunto(s)
Ceniza del Carbón , Metales Pesados , Biodiversidad , Ecosistema , Agua Dulce , Agua
8.
Cancers (Basel) ; 15(2)2023 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-36672367

RESUMEN

Background: The prognostic value of Immunoscore was evaluated in Stage II/III colon cancer (CC) patients, but it remains unclear in Stage I/II, and in early-stage subgroups at risk. An international Society for Immunotherapy of Cancer (SITC) study evaluated the pre-defined consensus Immunoscore in tumors from 1885 AJCC/UICC-TNM Stage I/II CC patients from Canada/USA (Cohort 1) and Europe/Asia (Cohort 2). METHODS: Digital-pathology is used to quantify the densities of CD3+ and CD8+ T-lymphocyte in the center of tumor (CT) and the invasive margin (IM). The time to recurrence (TTR) was the primary endpoint. Secondary endpoints were disease-free survival (DFS), overall survival (OS), prognosis in Stage I, Stage II, Stage II-high-risk, and microsatellite-stable (MSS) patients. RESULTS: High-Immunoscore presented with the lowest risk of recurrence in both cohorts. In Stage I/II, recurrence-free rates at 5 years were 78.4% (95%-CI, 74.4−82.6), 88.1% (95%-CI, 85.7−90.4), 93.4% (95%-CI, 91.1−95.8) in low, intermediate and high Immunoscore, respectively (HR (Hi vs. Lo) = 0.27 (95%-CI, 0.18−0.41); p < 0.0001). In Cox multivariable analysis, the association of Immunoscore to outcome was independent (TTR: HR (Hi vs. Lo) = 0.29, (95%-CI, 0.17−0.50); p < 0.0001) of the patient's gender, T-stage, sidedness, and microsatellite instability-status (MSI). A significant association of Immunoscore with survival was found for Stage II, high-risk Stage II, T4N0 and MSS patients. The Immunoscore also showed significant association with TTR in Stage-I (HR (Hi vs. Lo) = 0.07 (95%-CI, 0.01−0.61); P = 0.016). The Immunoscore had the strongest (69.5%) contribution χ2 for influencing survival. Patients with a high Immunoscore had prolonged TTR in T4N0 tumors even for patients not receiving chemotherapy, and the Immunoscore remained the only significant parameter in multivariable analysis. CONCLUSION: In early CC, low Immunoscore reliably identifies patients at risk of relapse for whom a more intensive surveillance program or adjuvant treatment should be considered.

9.
Astrobiology ; 22(10): 1255-1263, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-35796703

RESUMEN

Before the first humans depart for Mars in the next decade, hundreds of tons of martian water-ice must be harvested to produce propellant for the return vehicle, a process known as in situ resource utilization (ISRU). We describe here an instrument, the Agnostic Life Finder (ALF), that is an inexpensive life-detection add-on to ISRU. ALF exploits a well-supported view that informational genetic biopolymers in life in water must have two structural features: (1) Informational biopolymers must carry a repeating charge; they must be polyelectrolytes. (2) Their building blocks must fit into an aperiodic crystal structure; the building blocks must be size-shape regular. ALF exploits the first structural feature to extract polyelectrolytes from ∼10 cubic meters of mined martian water by applying a voltage gradient perpendicularly to the water's flow. This gradient diverts polyelectrolytes from the flow toward their respective electrodes (polyanions to the anode, polycations to the cathode), where they are captured in cartridges before they encounter the electrodes. There, they can later be released to analyze their building blocks, for example, by mass spectrometry or nanopore. Upstream, martian cells holding martian informational polyelectrolytes are disrupted by ultrasound. To manage the (unknown) conductivity of the water due to the presence of salts, the mined water is preconditioned by electrodialysis using porous membranes. ALF uses only resources and technology that must already be available for ISRU. Thus, life detection is easily and inexpensively integrated into SpaceX or NASA ISRU missions.


Asunto(s)
Medio Ambiente Extraterrestre , Marte , Exobiología , Humanos , Hielo , Polielectrolitos , Sales (Química) , Agua/química
10.
Immunotherapy ; 14(1): 31-40, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34784798

RESUMEN

Aim: To evaluate the effect of pleuran (ß-glucan from Pleurotus ostreatus) administration on the immune profile of patients with endocrine-dependent breast cancer (clinical stages I-II) in clinical and imaging remission. Methodology: Antitumor cellular immunity (CD19+, CD3+, CD4+ and CD8+ T lymphocytes and natural killer cells) of 195 patients (49 in the pleuran group and 146 in the control group) was measured by flow cytometry. Results: We observed a significant increase in the absolute number of CD3+, CD19+, CD4+ and CD8+ T lymphocytes in the pleuran group compared with the control group. Conclusion: Our results suggest potential benefit of continuous pleuran administration on immune rehabilitation of cellular antitumor immunity and better prognosis in breast cancer patients in remission.


Lay abstract We aimed to evaluate the effect of pleuran (ß-glucan from oyster mushroom) on the selected immune parameters of patients with breast cancer in remission. We studied antitumor cellular immune parameters of 195 patients (49 in the pleuran group and 146 in the control group) by means of flow cytometry. After 12 months, we measured a significant increase of cytotoxic T lymphocytes in the pleuran group compared with a significant decrease in the control group. Our results suggest potential benefit of long-term administration of pleuran on antitumor cellular immunity and better prognosis in breast cancer patients in remission.


Asunto(s)
Neoplasias de la Mama/inmunología , Inmunomodulación/inmunología , Pleurotus/inmunología , beta-Glucanos/inmunología , Femenino , Humanos , Persona de Mediana Edad
11.
EBioMedicine ; 77: 103926, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35290826

RESUMEN

BACKGROUND: Current SARS-CoV-2 detection platforms lack the ability to differentiate among variants of concern (VOCs) in an efficient manner. CRISPR/Cas (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated) based detection systems have the potential to transform the landscape of COVID-19 diagnostics due to their programmability; however, most of these methods are reliant on either a multi-step process involving amplification or elaborate guide RNA designs. METHODS: Three Cas12b proteins from Alicyclobacillus acidoterrestris (AacCas12b), Alicyclobacillus acidiphilus (AapCas12b), and Brevibacillus sp. SYP-B805 (BrCas12b) were expressed and purified, and their thermostability was characterised by differential scanning fluorimetry, cis-, and trans-cleavage activities over a range of temperatures. The BrCas12b was then incorporated into a reverse transcription loop-mediated isothermal amplification (RT-LAMP)-based one-pot reaction system, coined CRISPR-SPADE (CRISPR Single Pot Assay for Detecting Emerging VOCs). FINDINGS: Here we describe a complete one-pot detection reaction using a thermostable Cas12b effector endonuclease from Brevibacillus sp. to overcome these challenges detecting and discriminating SARS-CoV-2 VOCs in clinical samples. CRISPR-SPADE was then applied for discriminating SARS-CoV-2 VOCs, including Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Delta (B.1.617.2), and Omicron (B.1.1.529) and validated in 208 clinical samples. CRISPR-SPADE achieved 92·8% sensitivity, 99·4% specificity, and 96·7% accuracy within 10-30 min for discriminating the SARS-CoV-2 VOCs, in agreement with S gene sequencing, achieving a positive and negative predictive value of 99·1% and 95·1%, respectively. Interestingly, for samples with high viral load (Ct value ≤ 30), 100% accuracy and sensitivity were attained. To facilitate dissemination and global implementation of the assay, a lyophilised version of one-pot CRISPR-SPADE reagents was developed and combined with an in-house portable multiplexing device capable of interpreting two orthogonal fluorescence signals. INTERPRETATION: This technology enables real-time monitoring of RT-LAMP-mediated amplification and CRISPR-based reactions at a fraction of the cost of a qPCR system. The thermostable Brevibacillus sp. Cas12b offers relaxed primer design for accurately detecting SARS-CoV-2 VOCs in a simple and robust one-pot assay. The lyophilised reagents and simple instrumentation further enable rapid deployable point-of-care diagnostics that can be easily expanded beyond COVID-19. FUNDING: This project was funded in part by the United States-India Science & Technology Endowment Fund- COVIDI/247/2020 (P.K.J.), Florida Breast Cancer Foundation- AGR00018466 (P.K.J.), National Institutes of Health- NIAID 1R21AI156321-01 (P.K.J.), Centers for Disease Control and Prevention- U01GH002338 (R.R.D., J.A.L., & P.K.J.), University of Florida, Herbert Wertheim College of Engineering (P.K.J.), University of Florida Vice President Office of Research and CTSI seed funds (M.S.), and University of Florida College of Veterinary Medicine and Emerging Pathogens Institute (R.R.D.).


Asunto(s)
Brevibacillus , COVID-19 , Brevibacillus/genética , COVID-19/diagnóstico , Humanos , ARN Guía de Kinetoplastida , SARS-CoV-2/genética
12.
Chemistry ; 17(21): 5833-41, 2011 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-21472803

RESUMEN

Aqueous Suzuki-Miyaura cross-coupling reactions of halogenated nucleosides, nucleotides and nucleoside triphosphates derived from 5-iodocytosine and 7-iodo-7-deazaadenine with methyl-, benzyl- and tritylsufanylphenylboronic acids gave the corresponding alkylsulfanylphenyl derivatives of nucleosides and nucleotides. The modified nucleoside triphosphates were incorporated into DNA by primer extension by using Vent(exo-) polymerase. The electrochemical behaviour of the alkylsulfanylphenyl nucleosides indicated formation of compact layers on the electrode. Modified nucleotides and DNA with incorporated benzyl- or tritylsulfanylphenyl moieties produced signals in [Co(NH(3))(6)](3+) ammonium buffer, attributed to the Brdicka catalytic response, depending on the negative potential applied. Repeated constant current chronopotentiometric scans in this medium showed increased Brdicka catalytic response, which suggests the deprotection of the alkylsulfanyl derivatives to free thiols under the conditions.


Asunto(s)
Citosina/química , ADN Polimerasa Dirigida por ADN/química , Nucleósidos/química , Nucleósidos/metabolismo , Nucleótidos/química , Nucleótidos/metabolismo , Polifosfatos/química , Compuestos de Sulfhidrilo/química , Secuencia de Bases , ADN Polimerasa Dirigida por ADN/metabolismo , Electroquímica , Estructura Molecular
13.
Org Biomol Chem ; 9(5): 1366-71, 2011 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-21203615

RESUMEN

A simple approach to DNA tail-labelling using terminal deoxynucleotidyl transferase and modified deoxynucleoside triphosphates is presented. Amino- and nitrophenyl-modified dNTPs were found to be good substrates for this enzyme giving 3'-end stretches of different lengths depending on the nucleotide and concentration. 3-Nitrophenyl-7-deazaG was selected as the most useful label because its dNTP was efficiently incorporated by the transferase to form long tail-labels at any oligonucleotide. Accumulation of many nitrophenyl tags per oligonucleotide resulted in a considerable enhancement of voltammetric signals due to the nitro group reduction, thus improving the sensitivity of electrochemical detection of the tail-labelled probes. We demonstrate a perfect discrimination between complementary and non-complementary target DNAs sequences by tail-labelled hybridization probes as well as the ability of tumour suppressor p53 protein to recognize a specific binding site within tail-labelled DNA substrates, making the methodology useful in electrochemical DNA hybridization and DNA-protein interaction assays.


Asunto(s)
ADN Nucleotidilexotransferasa/química , Sondas de ADN/análisis , Proteínas de Unión al ADN/química , Técnicas Electroquímicas/métodos , Hibridación de Ácido Nucleico/métodos , Nucleótidos de Purina/química , Sondas de ADN/química , Estructura Molecular
14.
medRxiv ; 2021 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-34704101

RESUMEN

Current SARS-CoV-2 detection platforms lack the ability to differentiate among variants of concern (VOCs) in an efficient manner. CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) has the potential to transform diagnostics due to its programmability. However, many of the CRISPR-based detection methods are reliant on either a multi-step process involving amplification or elaborate guide RNA designs. A complete one-pot detection reaction using alternative Cas effector endonucleases has been proposed to overcome these challenges. Yet, current approaches using Alicyclobacillus acidiphilus Cas12b (AapCas12b) are limited by its thermal instability at optimum reverse transcription loop-mediated isothermal amplification (RT-LAMP) reaction temperatures. Herein, we demonstrate that a novel Cas12b from Brevibacillus sp. SYP-B805 (referred to as BrCas12b) has robust trans-cleavage activity at ideal RT-LAMP conditions. A competitive profiling study of BrCas12b against Cas12b homologs from other bacteria genera underscores the potential of BrCas12b in the development of new diagnostics. As a proof-of-concept, we incorporated BrCas12b into an RT-LAMP-mediated one-pot reaction system, coined CRISPR-SPADE (CRISPR Single Pot Assay for Detecting Emerging VOCs) to enable rapid, differential detection of SARS-CoV-2 VOCs, including Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) in 205 clinical samples. Notably, a BrCas12b detection signal was observed within 1-3 minutes of amplification, achieving an overall 98.1% specificity, 91.2% accuracy, and 88.1% sensitivity within 30 minutes. Significantly, for samples with high viral load (C t value ≤ 30), 100% accuracy and sensitivity were attained. To facilitate dissemination and global implementation of the assay, we combined the lyophilized one-pot reagents with a portable multiplexing device capable of interpreting fluorescence signals at a fraction of the cost of a qPCR system. With relaxed design requirements, one-pot detection, and simple instrumentation, this assay has the capability to advance future diagnostics.

15.
J Clin Oncol ; 38(31): 3638-3651, 2020 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-32897827

RESUMEN

PURPOSE: The purpose of this study was to evaluate the prognostic value of Immunoscore in patients with stage III colon cancer (CC) and to analyze its association with the effect of chemotherapy on time to recurrence (TTR). METHODS: An international study led by the Society for Immunotherapy of Cancer evaluated the predefined consensus Immunoscore in 763 patients with American Joint Committee on Cancer/Union for International Cancer Control TNM stage III CC from cohort 1 (Canada/United States) and cohort 2 (Europe/Asia). CD3+ and cytotoxic CD8+ T lymphocyte densities were quantified in the tumor and invasive margin by digital pathology. The primary end point was TTR. Secondary end points were overall survival (OS), disease-free survival (DFS), prognosis in microsatellite stable (MSS) status, and predictive value of efficacy of chemotherapy. RESULTS: Patients with a high Immunoscore presented with the lowest risk of recurrence, in both cohorts. Recurrence-free rates at 3 years were 56.9% (95% CI, 50.3% to 64.4%), 65.9% (95% CI, 60.8% to 71.4%), and 76.4% (95% CI, 69.3% to 84.3%) in patients with low, intermediate, and high immunoscores, respectively (hazard ratio [HR; high v low], 0.48; 95% CI, 0.32 to 0.71; P = .0003). Patients with high Immunoscore showed significant association with prolonged TTR, OS, and DFS (all P < .001). In Cox multivariable analysis stratified by participating center, Immunoscore association with TTR was independent (HR [high v low], 0.41; 95% CI, 0.25 to 0.67; P = .0003) of patient's sex, T stage, N stage, sidedness, and microsatellite instability status. Significant association of a high Immunoscore with prolonged TTR was also found among MSS patients (HR [high v low], 0.36; 95% CI, 0.21 to 0.62; P = .0003). Immunoscore had the strongest contribution χ2 proportion for influencing survival (TTR and OS). Chemotherapy was significantly associated with survival in the high-Immunoscore group for both low-risk (HR [chemotherapy v no chemotherapy], 0.42; 95% CI, 0.25 to 0.71; P = .0011) and high-risk (HR [chemotherapy v no chemotherapy], 0.5; 95% CI, 0.33 to 0.77; P = .0015) patients, in contrast to the low-Immunoscore group (P > .12). CONCLUSION: This study shows that a high Immunoscore significantly associated with prolonged survival in stage III CC. Our findings suggest that patients with a high Immunoscore will benefit the most from chemotherapy in terms of recurrence risk.


Asunto(s)
Antineoplásicos/uso terapéutico , Linfocitos T CD8-positivos , Neoplasias del Colon/tratamiento farmacológico , Neoplasias del Colon/inmunología , Recurrencia Local de Neoplasia/inmunología , Anciano , Anciano de 80 o más Años , Complejo CD3/metabolismo , Linfocitos T CD8-positivos/metabolismo , Quimioterapia Adyuvante , Neoplasias del Colon/genética , Neoplasias del Colon/patología , Supervivencia sin Enfermedad , Femenino , Humanos , Recuento de Linfocitos , Linfocitos Infiltrantes de Tumor , Masculino , Inestabilidad de Microsatélites , Persona de Mediana Edad , Mutación , Estadificación de Neoplasias , Valor Predictivo de las Pruebas , Tasa de Supervivencia , Factores de Tiempo
16.
Chem Sci ; 6(1): 575-587, 2015 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-28970873

RESUMEN

New redox labelling of DNA by an azido group which can be chemically transformed to nitrophenyltriazole or silenced to phenyltriazole was developed and applied to the electrochemical detection of DNA-protein interactions. 5-(4-Azidophenyl)-2'-deoxycytidine and 7-(4-azidophenyl)-7-deaza-2'-deoxyadenosine nucleosides were prepared by aqueous-phase Suzuki cross-coupling and converted to nucleoside triphosphates (dNTPs) which served as substrates for incorporation into DNA by DNA polymerase. The azidophenyl-modified nucleotides and azidophenyl-modified DNA gave a strong signal in voltammetric studies, at -0.9 V, due to reduction of the azido function. The Cu-catalyzed click reaction of azidophenyl-modified nucleosides or azidophenyl-modified DNA with 4-nitrophenylacetylene gave nitrophenyl-substituted triazoles, exerting a reduction peak at -0.4 V under voltammetry, whereas the click reaction with phenylacetylene gave electrochemically silent phenyltriazoles. The transformation of the azidophenyl label to nitrophenyltriazole was used for electrochemical detection of DNA-protein interactions (p53 protein) since only those azidophenyl groups in the parts of the DNA not shielded by the bound p53 protein were transformed to nitrophenyltriazoles, whereas those covered by the protein were not.

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