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International Journal of Molecular... May 2020Starting from dansyl-chloride, in reaction with 1,1-diphenylhydrazine and methoxyamine, two new fluorescent derivatives and were obtained and characterized by NMR, IR,...
Starting from dansyl-chloride, in reaction with 1,1-diphenylhydrazine and methoxyamine, two new fluorescent derivatives and were obtained and characterized by NMR, IR, UV-Vis, HR-MS, and fluorescence spectroscopy. The single-crystal X-ray structure was obtained for compound . Both compounds generate free radicals by oxidation, as demonstrated by ESR spectroscopy. Compound generates the corresponding hydrazyl-persistent free radical, evidenced directly by ESR spectroscopy, while compound generates in the first instance the methoxyaminyl short-lived free radical, which decomposes rapidly with the formation of the methoxy radical, evidenced by the ESR spin-trapping technique. By oxidation of compounds and , their fluorescence is quenched.
Topics: Dansyl Compounds; Electron Spin Resonance Spectroscopy; Free Radicals; Hydroxylamines; Phenylhydrazines; Spin Trapping
PubMed: 32443620
DOI: 10.3390/ijms21103559 -
Experimental Biology and Medicine... Jun 2016The purpose of this study was to evaluate the combination effect of resveratrol and methoxyamine on radiosensitivity of iododeoxyuridine in spheroid culture of U87MG...
The purpose of this study was to evaluate the combination effect of resveratrol and methoxyamine on radiosensitivity of iododeoxyuridine in spheroid culture of U87MG glioblastoma cell line using colony formation and alkaline comet assays. Spheroids on day-20 with 350 µm diameters were treated with 20 µM resveratrol and/or 6 mM methoxyamine and/or 1 µM iododeoxyuridine for one volume doubling time (67 h), and then irradiated with 2 Gy gamma-radiation ((60)Co) in different groups. After treatment, viability of the cells, colony forming ability and DNA damages were obtained by blue dye exclusion, colony formation and alkaline comet assay, respectively. Our results showed that methoxyamine and resveratrol could significantly reduce colony number and induce the DNA damages of glioblastoma spheroid cells treated with iododeoxyuridine in combination with gamma-rays. Therefore, methoxyamine as base excision repair inhibitor and resveratrol as hypoxia inducible factor 1-alpha inhibitor in combination with iododeoxyuridine as radiosensitizer enhanced the radiosensitization of glioblastoma spheroid cells.
Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Survival; Colony-Forming Units Assay; Comet Assay; Gamma Rays; Humans; Hydroxylamines; Idoxuridine; Neuroglia; Radiation Tolerance; Radiation-Sensitizing Agents; Resveratrol; Stilbenes
PubMed: 26748400
DOI: 10.1177/1535370215622583 -
Metabolites Aug 2022Preterm birth (PTB) is a social problem that adversely affects not only the survival rate of the fetus, but also the premature babies and families, so there is an urgent...
Preterm birth (PTB) is a social problem that adversely affects not only the survival rate of the fetus, but also the premature babies and families, so there is an urgent need to find accurate biomarkers. We noted that among causes, eubiosis of the vaginal microbial community to dysbiosis leads to changes in metabolite composition. In this study, short chain fatty acids (SCFAs) representing dysbiosis were derivatized using (-butyldimethylsilyl--methyltrifluoroacetamide, MTBSTFA) and targeted analysis was conducted in extracted organic phases of cervicovaginal fluid (CVF). In residual aqueous CVF, polar metabolites produced biochemistry process were derivatized using methoxyamine and ,-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and non-targeted analysis were conducted. Nine SCFAs were quantified, and 58 polar metabolites were detected in 90 clinical samples using gas chromatography/mass spectrometry (GC/MS). The criteria of statistical analysis and detection rate of clinical sample for development of PTB biomarkers were presented, and 19 biomarkers were selected based on it, consisting of 1 SCFA, 2 organic acids, 4 amine compounds, and 12 amino acids. In addition, the model was evaluated as a suitable indicator for predicting PTB without distinction between sample collection time. We hope that the developed biomarkers based on microbiota-derived metabolites could provide useful diagnostic biomarkers for actual patients and pre-pregnancy.
PubMed: 36005605
DOI: 10.3390/metabo12080734 -
PloS One 2018To investigate the photochemical degradation of trypan blue (TB) and to identify decomposition products.
PURPOSE
To investigate the photochemical degradation of trypan blue (TB) and to identify decomposition products.
METHODS
Defined solution samples of TB and a mixture with lutein/zeaxanthin were exposed to blue light. Thermal degradation processes were ruled out using controls not subjected to irradiation. All samples were analyzed using optical microscopy, UV/Vis spectroscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and nuclear magnetic resonance (NMR) spectrometry. Degradation kinetics were determined based on changes in absorbance; intermediates were identified by analyzing mass differences of characteristic fragment ion peaks within the fragmentation patterns, and assignments were verified by NMR.
RESULTS
TB demonstrated a photochemical degradation, which can be triggered by lutein/zeaxanthin. Intermediates vary depending on the presence of lutein/zeaxanthin. The self-sensitized photodegradation of TB occurs under generation of dimethyl sulfate and presumed formation of phenol. In contrast, within the presence of lutein/zeaxanthin the decomposition of TB indicates the formation of methoxyamine and sulfonyl arin. Thermal degradation processes were not observed.
CONCLUSIONS
TB demonstrated a photodegradation that may be triggered by lutein/zeaxanthin and results in the formation of cytotoxic decomposition products. Our findings contribute to understand degradation mechanisms of TB and may elucidate previous clinical and experimental observations of cellular toxicity after TB application.
Topics: Kinetics; Light; Lutein; Photochemistry; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Trypan Blue; Zeaxanthins
PubMed: 29634764
DOI: 10.1371/journal.pone.0195849 -
Antibiotics (Basel, Switzerland) Mar 2019Fluorescent probes are widely used for imaging and measuring dynamic processes in living cells. Fluorescent antibiotics are valuable tools for examining...
Fluorescent probes are widely used for imaging and measuring dynamic processes in living cells. Fluorescent antibiotics are valuable tools for examining antibiotic⁻bacterial interactions, antimicrobial resistance and elucidating antibiotic modes of action. Profluorescent nitroxides are 'switch on' fluorescent probes used to visualize and monitor intracellular free radical and redox processes in biological systems. Here, we have combined the inherent fluorescent and antimicrobial properties of the fluoroquinolone core structure with the fluorescence suppression capabilities of a nitroxide to produce the first example of a profluorescent fluoroquinolone-nitroxide probe. Fluoroquinolone-nitroxide (FN) exhibited significant suppression of fluorescence (>36-fold), which could be restored via radical trapping (fluoroquinolone-methoxyamine ) or reduction to the corresponding hydroxylamine . Importantly, FN was able to enter both Gram-positive and Gram-negative bacterial cells, emitted a measurable fluorescence signal upon cell entry (switch on), and retained antibacterial activity. In conclusion, profluorescent nitroxide antibiotics offer a new powerful tool for visualizing antibiotic⁻bacterial interactions and researching intracellular chemical processes.
PubMed: 30836686
DOI: 10.3390/antibiotics8010019 -
Investigational New Drugs Feb 2021Temozolomide (TMZ) generates DNA adducts that are repaired by direct DNA and base excision repair mechanisms. Methoxyamine (MX, TRC-102) potentiates TMZ activity by...
Temozolomide (TMZ) generates DNA adducts that are repaired by direct DNA and base excision repair mechanisms. Methoxyamine (MX, TRC-102) potentiates TMZ activity by binding to apurinic and apyrimidinic (AP) sites after removal of N-methyladenine and N-methylguanine, inhibiting site recognition of AP endonuclease. We conducted a phase I trial to determine the maximum tolerated dose and dose-limiting toxicities (DLTs) of intravenous MX when given with oral TMZ. Patients with advanced solid tumors and progression on standard treatment were enrolled to a standard 3 + 3 dose escalation trial assessing escalating doses of TMZ and MX. Tumor response was assessed per RECIST and adverse events (AEs) by CTCAEv3. Pharmacokinetics (PK) of MX and COMET assays on peripheral blood mononuclear cells were performed. 38 patients were enrolled-median age 59.5 years (38-76), mean number of cycles 2.9 [1-13]. No DLTs were observed. Cycle 1 grade 3 AEs included fatigue, lymphopenia, anemia, INR, leukopenia, neutropenia, allergic reaction, constipation, psychosis and paranoia. Cycle 2-13 grade 4 AEs included thrombocytopenia and confusion. A partial response was seen in 1 patient with a pancreatic neuroendocrine tumor (PNET) and six additional patients, each with different tumor types, demonstrated prolonged stable disease. MX PK was linear with dose and was not affected by concomitant TMZ. TMZ 200 mg/m daily × 5 may be safely administered with MX 150 mg/m intravenously once on day 1 with minimal toxicity. Further studies assessing this drug combination in select tumor types where temozolomide has activity may be warranted.
Topics: Adult; Aged; Antineoplastic Agents, Alkylating; Antineoplastic Combined Chemotherapy Protocols; Area Under Curve; DNA Repair; Dose-Response Relationship, Drug; Drug Synergism; Female; Half-Life; Humans; Hydroxylamines; Male; Maximum Tolerated Dose; Metabolic Clearance Rate; Middle Aged; Neoplasms; Temozolomide
PubMed: 32556884
DOI: 10.1007/s10637-020-00962-x -
Cell Journal 2017This study intended to observe the effects of methoxyamine (Mx) on cytotoxic effects and DNA damage caused by 5-Fluorouracil (5-FU) in combination with gamma radiation...
OBJECTIVE
This study intended to observe the effects of methoxyamine (Mx) on cytotoxic effects and DNA damage caused by 5-Fluorouracil (5-FU) in combination with gamma radiation in a human colon cancer cell line, HT29.
MATERIALS AND METHODS
In this experimental study, HT29 cells were cultured as a monolayer and treated with different concentrations of 5-FU along with 1 mM Mx for 24 hours. Next, the cells were irradiated with 2 Gy gamma radiation. After the treatments, we assessed for DNA damage, cytotoxicity, and viability by alkaline comet, clonogenic survival, and trypan blue dye exclusion assays.
RESULTS
Cytotoxicity and DNA damage increased with increasing 5-FU concentration. The 1 mM Mx concentration had no significant effect on cytotoxicity and DNA damage from 5-FU; however, it increased the cytotoxic and genotoxic effects of different concentrations of 5-FU when used in combination with 2 Gy gamma radiation.
CONCLUSION
Mx combined with 5-FU enhanced the radiosensitivity of colon cancer cells.
PubMed: 28670521
DOI: 10.22074/cellj.2016.4295 -
European Journal of Pharmaceutical... Oct 2020Atomoxetine (ATX), a selective and potent inhibitor of the presynaptic norepinephrine transporter, is used mainly to treat attention-deficit hyperactivity disorder....
Atomoxetine (ATX), a selective and potent inhibitor of the presynaptic norepinephrine transporter, is used mainly to treat attention-deficit hyperactivity disorder. Although multiple adverse effects associated with ATX have been reported including severe liver injuries, the mechanisms of ATX-related toxicity remain largely unknown. Metabolism frequently contributes to adverse effects of a drug through reactive metabolites, and the bioactivation status of ATX is still not investigated yet. Here, we systematically investigated ATX metabolism, bioactivation, species difference in human, mouse, and rat liver microsomes (HLM, MLM, and RLM) and in mice using metabolomic approaches as mice and rats are commonly used animal models for the studies of drug toxicity. We identified thirty one ATX metabolites and adducts in LMs and mice, 16 of which are novel. In LMs, we uncovered two methoxyamine-trapped aldehydes, two cyclization metabolites, detoluene-ATX, and ATX-N-hydroxylation for the first time. Detoluene-ATX and one cyclization metabolite were also observed in mice. Using chemical inhibitors and recombinant CYP enzymes, we demonstrated that CYP2C8 and CYP2B6 mainly contribute to the formation of aldehyde; CYP2D6 is the dominant enzyme for the formation of ATX cyclization and detoluene-ATX; CYP3A4 is major enzyme responsible for the hydroxylamine formation. The findings concerning aldehydes should be very useful to further elucidate the mechanistic aspects of adverse effects associated with ATX from metabolic angles. Additionally, the species differences for each metabolite should be helpful to investigate the contribution of specific metabolites to ATX toxicity and possible drug-drug interactions in suitable models.
Topics: Animals; Atomoxetine Hydrochloride; Attention Deficit Disorder with Hyperactivity; Metabolomics; Mice; Microsomes, Liver; Norepinephrine; Rats
PubMed: 32712217
DOI: 10.1016/j.ejps.2020.105488 -
Astronomy and Astrophysics Jan 2018Methoxyamine is a potential interstellar amine that has been predicted by gas-grain chemical models for the formation of complex molecules. The aim of this work is to...
AIMS
Methoxyamine is a potential interstellar amine that has been predicted by gas-grain chemical models for the formation of complex molecules. The aim of this work is to provide direct experimental frequencies of its ground-vibrational state in the millimeter- and submillimeter-wave regions to achieve its detection in the interstellar medium.
METHODS
Methoxyamine was chemically liberated from its hydrochloride salt, and its rotational spectrum was recorded at room temperature from 75 to 480 GHz using the millimeter-wave spectrometer in Valladolid. Many observed transitions revealed - splitting caused by the internal rotation of the methyl group, which had to be treated with specific internal rotation codes.
RESULTS
Over 400 lines were newly assigned for the most stable conformer of methoxyamine, and a precise set of spectroscopic constants was obtained. Spectral features of methoxyamine were then searched for in the Orion KL, Sgr B2, B1-b, and TMC-1 molecular clouds. Upper limits to the column density of methoxyamine were derived.
PubMed: 29983447
DOI: 10.1051/0004-6361/201730744 -
PloS One 2015Indoleamine 2,3-dioxygenase-1 (IDO) is an immune regulatory enzyme expressed by most human tumors. IDO levels in tumor cells correlate with increased metastasis and poor...
Indoleamine 2,3-dioxygenase-1 (IDO) is an immune regulatory enzyme expressed by most human tumors. IDO levels in tumor cells correlate with increased metastasis and poor patient outcome and IDO is linked to tumor cell resistance to immunotherapy, radiation therapy, and chemotherapy. Knowledge of tumor cell-autonomous effects of IDO, independent of its well-known role in regulating and suppressing anti-tumor immune responses, is limited. Clonal populations of A549 human lung adenocarcinoma cells stably transfected with anti-IDO shRNA or scrambled control shRNA were used to study IDO effects on drug sensitivity and resistance. IFNγ was used to induce IDO in those cells. We show, for the first time, that IDO mediates human tumor cell resistance to the candidate anticancer drugs FK866 (an NAD+ inhibitor), methoxyamine (MX, a base excision repair [BER] inhibitor) and approved anticancer drugs pemetrexed (a folate anti-metabolite) and gemcitabine (a nucleoside analogue), and combined treatment with pemetrexed and MX, in the absence of immune cells. Concurrent knockdown of IDO and thymidylate synthase (TS, a key rate-limiting enzyme in DNA synthesis and repair) sensitizes human lung cancer cells to pemetrexed and 5FUdR to a greater degree than knockdown of either target alone. We conclude that BER in IDO-expressing A549 cells plays a major role in mediating resistance to a range of approved and candidate anticancer drugs. IDO inhibitors are undergoing clinical trials primarily to improve antitumor immune responses. We show that targeting IDO alone or in combination with TS is a potentially valuable therapeutic strategy for cancer treatment, independent of immune activity and in combination with conventional chemotherapy.
Topics: Acrylamides; Animals; BRCA2 Protein; Cell Line, Tumor; Clone Cells; DNA Repair; Deoxycytidine; Down-Regulation; Drug Resistance, Neoplasm; Enzyme Induction; Floxuridine; Gene Knockdown Techniques; Humans; Hydroxylamines; Indoleamine-Pyrrole 2,3,-Dioxygenase; Mice, SCID; NAD; Pemetrexed; Piperidines; RNA, Small Interfering; Thymidylate Synthase; Xenograft Model Antitumor Assays; Gemcitabine
PubMed: 26579709
DOI: 10.1371/journal.pone.0143435