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2-thioxanthone thioacetic acid (TXSCH2COOH, T), which has a fluorometric character, was used for new fluorometric system upon Fe(II) analysis in biological samples as the main target. T-BSA binary ...

Fluorescent probes for the detection of acid phosphatases (ACP) are important in the investigation of the pathology and diagnosis of diseases. We reported a lysosome-targeted near-infrared (NIR) fluorescent probe SHCy-P based on a novel NIR-emitting thioxanthene-indolium dye for the detection of ACP. The probe showed a long wavelength fluorescence emission at λem = 765 nm. Due to the ACP-catalyzed cleavage of the phosphate group in SHCy-P, the probe exhibited high selectivity and sensitivity for the 'turn-on' detection of ACP with a limit of detection as low as 0.48 U L-1. The probe SHCy-P could also be used to detect and image endogenous ACP in lysosomes. In light of these prominent properties, we envision that SHCy-P will be an efficient optical imaging approach for investigating the ACP activity in disease diagnosis.

Mutational outcomes following CRISPR-Cas9-nuclease cutting in mammalian cells have recently been shown to be predictable and, in certain cases, skewed toward single genotypes. However, the ability to control these outcomes remains limited, especially for 1-bp insertions, a common and therapeutically relevant class of repair outcomes. Here, through a small molecule screen, we identify the ATM kinase inhibitor KU-60019 as a compound capable of reproducibly increasing the fraction of 1-bp insertions relative to other Cas9 repair outcomes. Small molecule or genetic ATM inhibition increases 1-bp insertion outcome fraction across three human and mouse cell lines, two Cas9 species, and dozens of target sites, although concomitantly reducing the fraction of edited alleles. Notably, KU-60019 increases the relative frequency of 1-bp insertions to over 80% of edited alleles at several native human genomic loci and improves the efficiency of correction for pathogenic 1-bp deletion variants. The ability to increase 1-bp insertion frequency adds another dimension to precise template-free Cas9-nuclease genome editing., The mutational outcome of CRISPR-Cas9 editing can be both predictable and targeted. Here the authors show that ATM inhibitor KU-60019 increases 1 bp insertions at the targeted locus.

Herein, we first report an electrochemical methodology for the site-selective alkylation of azobenzenes with (thio)xanthenes in the absence of any transition metal catalyst or external oxidant. A variety of groups are compatible with this electrochemical alkylation, which furnishes the products in moderate to good yields.

In the present study, a comprehensive and sensitive method for simultaneous determination of 21 PIs (nine benzophenones, eight amine co-initiators, and four thioxanthones) in human plasma using high-performance liquid chromatography coupled with tandem mass spectrometry was developed and validated. Two different pre-treatment approaches (liquid-liquid extraction (LLE) and LLE coupled with solid-phase extraction (SPE)) and eight extraction solvents were studied to optimize sample treatment to obtain good recoveries and reduce any matrix effects. The procedure of LLE+SPE was selected as final sample treatment procedure because it obtained higher recoveries as well as lower matrix effects than that performed by LLE alone. The recoveries of 21 target analytes at three spiked concentrations (0.05, 0.5, and 5 ng/mL) ranged from 81% to 109%. The intra- and inter-day relative standard deviations were between 2.5% and 13%. Accuracy and precision data indicated that the detection method was accurate and precise for most of the PIs. The linearities of the labeled dilution calibration curves at 10 concentration levels (iLOQ to 100 ng/mL or iLOQ to 200 ng/mL) were good with correlation coefficients ranged from 0.995 to 0.999. The method quantification limits were in the range of 1.7-16 pg/mL. The analytical method was applied to the analysis of PIs in 14 human plasma samples collected from pregnant women in Guangdong Province, China. Fifteen PIs were detected with total concentrations ranging from 318 to 2772 pg/mL. The ubiquitous contamination of human plasma with PIs suggests that there is widespread exposure to these compounds. Consequently, there should be increased awareness of these pollutants in the environment.

A rhodium-catalyzed direct C-H arylation of naphthalene and anthracene was developed with the assistance of a thioether directing group. The reaction proceeded with exclusive peri-selectivity, and the series of coupling products were readily transformed into the corresponding sulfur-containing polyaromatics. Charge-transport properties of the provided dithiapyrenes were evaluated by computational studies.

An efficient organocatalytic route has been developed to synthesize novel substituted thioxanthenes (2a–2v) starting from diaryl thioether alcohols (1a–1v) using the intramolecular Friedel–Crafts r...

PTEN deficiency often causes defects in DNA damage repair. Currently, effective therapies for breast cancer are lacking. ATM is an attractive target for cancer treatment. Previous studies suggested a synthetic lethality between PTEN and PARP. However, the synthetically lethal interaction between PTEN and ATM in breast cancer has not been reported. Moreover, the mechanism remains elusive. Here, using KU-60019, an ATM kinase inhibitor, we investigated ATM inhibition as a synthetically lethal strategy to target breast cancer cells with PTEN defects. We found that KU-60019 preferentially sensitizes PTEN-deficient MDA-MB-468 breast cancer cells to cisplatin, though it also slightly enhances sensitivity of PTEN wild-type breast cancer cells. The increased cytotoxic sensitivity is associated with apoptosis, as evidenced by flow cytometry and PARP cleavage. Additionally, the increase of DNA damage accumulation due to the decreased capability of DNA repair, as indicated by γ-H2AX and Rad51 foci, also contributed to this selective cytotoxicity. Mechanistically, compared with PTEN wild-type MDA-MB-231 cells, PTEN-deficient MDA-MB-468 cells have lower level of Rad51, higher ATM kinase activity, and display the elevated level of DNA damage. Moreover, these differences could be further enlarged by cisplatin. Our findings suggest that ATM is a promising target for PTEN-defective breast cancer.

BACKGROUND Previous studies revealed physiological and pathogenetic similarity between vascular smooth muscles cells with severe pulmonary arterial hypertension and tumors. The DNA damage response was found in both pulmonary arterial hypertension (PAH) cells and tumors. The ataxia-telangiectasia mutated proteins (ATM) pathway is considered an important factor in the DNA damage response of tumor formation, but its function in the development of PAH remains unknown. MATERIAL AND METHODS The Sprague-Dawley rat PAH model was established. Three weeks (Group M1), 5 weeks (Group M2), and 7 weeks (Group M3) after drug injection, pulmonary expression of ATM, Checkpoint kinase 2 (Chk2), P53, and P21 were measured. A section of the lungs from Group M2 was used for pulmonary artery vascular smooth muscles cells (PA-SMCs) isolation and culture. The effect of KU60019 in the proliferation and apoptosis of primary cultured rat PA-SMCs was measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and TdT-mediated dUTP nick-end labeling (TUNEL), respectively. RESULTS Immunohistochemistry results show that the expression of ATM, Chk2, and P21 increased in Groups M1 and M2, and decreased in Group M3. Additionally, expression of P53 increased in Group M1, and decreased in Groups M2 and M3. RT-PCR and Western blotting demonstrated that in Groups M1 and M2, the expression of ATM, Chk2, P53, and P21 increased, whereas it decreased in Group M3. In cell culture, 0.3 μM and 0.5 μM KU60019 increased the growth of PA-SMCs, and 0.5 μM KU60019 reduced cell apoptosis. CONCLUSIONS Expression of the ATM-Chk2 pathway increased in early stages of PAH formation, but decreased in late stages. In primary cultured PA-SMCs, KU60019 increased cell proliferation and inhibited cell apoptosis.

A simple catalytic oxidation system was developed for the selective aerobic oxidation of structurally diverse benzylic sp3 CH bonds of ethers and alkylarenes. The reactions were performed with Fe(NO3)3·9H2O as the catalyst, KPF6 as the additive and molecular oxygen as the terminal oxidant without any ligands. Under the optimal reaction conditions, a number of isochromans, xanthenes and thioxanthenes can be converted to their corresponding esters or ketones in good to excellent yields.

In this study, a thioxanthone derivative, 2-Thioxanthone Thioacetic Acid (TXSCH2COOH) was used to analyze the type of binding to calf thymus DNA in a physiological buffer (Tris-HCl buffer solution, pH:7.0). Several spectroscopic techniques were employed including UV–Vis absorption and fluorescence emission spectroscopy and viscosity measurements were also used to clarify the binding mode of TXSCH2COOH to ct-DNA. The intrinsic binding constant Kb of TXSCH2COOH-ct-DNA was found as 2.5 × 103 M−1 from the absorption studies. Increasing of fluorescence emission intensity was found approximately 74.4% by adding ct-DNA to the TXSCH2COOH solution. Fluorescence microscopy was employed to display imaging of the TXSCH2COOH-ct-DNA solution. Increasing of the iodide quenching effect was observed when TXSCH2COOH was added to the double stranded DNA and the calculated quenching constants of TXSCH2COOH and TXSCH2COOH-ct-DNA were found to be 1.89 × 103 M−1 and 1.19 × 104 M−1, respectively. Additionally, the iodide quenching experiment was conducted with single stranded DNA which led to a high Ksv value. All the experimental results including the viscosity values of ct-DNA with TXSCH2COOH demonstrated that the binding of TXSCH2COOH to ct-DNA was most likely groove binding. Furthermore, TXSCH2COOH was found to be an A-T rich minor groove binder. This was confirmed by the displacement assays with Hoechst 33258 compared to Ethidium Bromide. The in vitro cytotoxic activity measurements were performed by MTT assay on HT29 cell line for 72 h. TXSCH2COOH exhibited notable cytotoxic activities compared to the standard chemotherapy drugs, fluorouracil (5-FU), cisplatin in tumorigenic HT29 cell line. The 50% growth-inhibitory concentration (IC50) for TXSCH2COOH was 19,8 μg/mL while 5-FU and cisplatin were 28.9 μg/mL, 20 μg/mL, respectively. The increase in cytotoxic effect when TXSCH2COOH is activated by light indicates the potential of being theranostic cancer drug candidate.

Cysteine (Cys) is one of the most important essential biothiols in lysosomes. Highly selective probes for specific detection and imaging of lysosomal Cys over other biological thiols are rare. Herein, we developed a lysosome-targeted near-infrared fluorescent probe SHCy-C based on a novel NIR-emitting thioxanthene-indolium dye. Due to the turn-on fluorescence response elicited by the intramolecular charge transfer (ICT) processes before and after the reaction with Cys, probe SHCy-C exhibits high selectivity and sensitivity (16 nM) for the detection of Cys. More importantly, probe SHCy-C is found to precisely target lysosomes and achieves the "turn-on" detection and imaging of endogenous Cys in lysosomes.

Resistance to radiotherapy is one of the main causes of treatment failure in patients with nasopharyngeal carcinoma (NPC). Epstein-Barr virus (EBV) infection is an important factor in the pathogenesis of NPC, and EBV-encoded microRNAs (miRNAs) promote NPC progression. However, the role of EBV-encoded miRNAs in the radiosensitivity of NPC remains unclear. Here, we investigated the effects of EBV-miR-BART8-3p on radiotherapy resistance in NPC cells in vitro and in vivo, and explored the underlying molecular mechanisms. Inhibitors of ataxia telangiectasia mutated (ATM)/ataxia telangiectasia mutated and Rad3-related (ATR) (KU60019 and AZD6738, respectively) were used to examine radiotherapy resistance. We proved that EBV-miR-BART8-3p promoted NPC cell proliferation in response to irradiation in vitro and associated with the induction of cell cycle arrest at the G2/M phase, which was a positive factor for the DNA repair after radiation treatment. Besides, EBV-miR-BART8-3p could increase the size of xenograft tumors significantly in nude mice. Treatment with KU60019 or AZD6738 increased the radiosensitivity of NPC by suppressing the expression of p-ATM and p-ATR. The present results indicate that EBV-miR-BART8-3p promotes radioresistance in NPC by modulating the activity of ATM/ATR signaling pathway.

Thioxanthone and its analogues, 2- or 4-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone (DETX) and xanthone, are used as photoinitiators of ultraviolet (UV) light-initiated curable inks. As these photoinitiators were found in numerous food/beverage products packaged in cartons printed with UV-cured inks, the cytotoxic effects and mechanisms of these compounds were studied in freshly isolated rat hepatocytes. The toxicity of DETX was greater than that of other compounds. DETX elicited not only concentration (0-2.0 mm)- and time (0-3 hours)-dependent cell death accompanied by the depletion of cellular adenosine triphosphate (ATP), and reduced glutathione (GSH) and protein thiol levels, but also the accumulation of GSH disulfide and malondialdehyde. Pretreatment of hepatocytes with either fructose at a concentration of 10 mm or N-acetyl-l-cysteine (NAC) at a concentration of 5.0 mm ameliorated DETX (1 mm)-induced cytotoxicity. Further, the exposure of hepatocytes to DETX resulted in the induction of reactive oxygen species (ROS) and loss of mitochondrial membrane potential, both of which were partially prevented by the addition of NAC. These results indicate that: (1) DETX-induced cytotoxicity is linked to mitochondrial failure and depletion of cellular GSH; (2) insufficient cellular ATP levels derived from mitochondrial dysfunction were, at least in part, ameliorated by the addition of fructose; and (3) GSH loss and/or ROS formation was prevented by NAC. Taken collectively, these results suggest that the onset of toxic effects caused by DETX may be partially attributable to cellular energy stress as well as oxidative stress.

MYCN amplification or N-Myc overexpression is found in approximately 40% NEPC and up to 20% CRPC patients. N-Myc has been demonstrated to drive disease progression and hormonal therapeutic resistance of NEPC/CRPC. Here, we aim to identify the molecular mechanisms underlying the N-Myc-driven therapeutic resistance and provide new therapeutic targets for those N-Myc overexpressed NEPC/CRPC.N-Myc overexpressing stable cell lines for LNCaP and C4-2 were generated by lentivirus infection. ADT-induced senescence was measured by SA-β-gal staining in LNCaP cells in vitro and in LNCaP xenograft tumors in vivo. Migration, cell proliferation and colony formation assays were used to measure the cellular response after overexpressing N-Myc or perturbing the miR-421/ATM pathway. CRISPR-Cas9 was used to knock out ATM in C4-2 cells and MTS cell viability assay was used to evaluate the drug sensitivity of N-Myc overexpressing C4-2 cells in response to Enzalutamide and ATM inhibitor Ku60019 respectively or in combination.N-Myc overexpression suppressed ATM expression through upregulating miR-421 in LNCaP cells. This suppression alleviated the ADT-induced senescence in vitro and in vivo. Surprisingly, N-Myc overexpression upregulated ATM expression in C4-2 cells and this upregulation promoted migration and invasion of prostate cancer cells. Further, the N-Myc-induced ATM upregulation in C4-2 cells rendered the cells resistance to Enzalutamide, and inhibition of ATM by CRISPR-Cas9 knockout or ATM inhibitor Ku60019 re-sensitized them to Enzalutamide.N-Myc differentially regulating miR-421/ATM pathway contributes to ADT resistance and Enzalutamide resistance development respectively. Combination treatment with ATM inhibitor re-sensitizes N-Myc overexpressed CRPC cells to Enzalutamide. Our findings would offer a potential combination therapeutic strategy using ATM kinase inhibitor and Enzalutamide for the treatment of a subset of mCRPC with N-Myc overexpression that accounts for up to 20% CRPC patients.

Photoinitiators (PIs) are widely used for photopolymerization in industrial area and recently paid close attention to in biomedical field. However, there are few reports on their toxicity to human health. Here we explored cytotoxicity and cytocompatibilty of seven commercial and industrial-used PIs for developing their potential clinical application. Phenylbis(acyl) phosphine oxides (BAPO), 2-Benzyl-2-(dimethylamino)-4′-morpholinobutyrophenone (369), 4,4’-Bis(diethylamino) benzophenone (EMK), Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO), and 2-Isopropylthioxanthone (ITX) caused different extent cytotoxicities to four tissue types of cells at the concentrations of 1 to 50 μM under a non-irradiation condition, of which the BAPO cytotoxicity was the highest, whereas Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate (TPOL) and Methyl benzoylformate (MBF) displayed the lowest cellular toxicity. The cell lines and primary cells appeared highly sensitive to BAPO toxicity, the primary lymphocytes relatively to photoinitiator 369 (369) and EMK toxicities, LO2 cells to EMK and TPO toxicities, the primary lymphocytes and HUVEC-12 cells to MBF toxicity, but only HEK293T cells not to 369 toxicity. Furthermore, these PIs led to increasing cytotoxicity to different extents after exposure to 455 nm blue light, which is consistent with non-irradiation tendency. All the cells presented low sensitivity to TPOL and MBF, of which TPOL-triggered polymer is dramatically superior in its cytocompatibility to MBF, and in its transparency to clinically exclusively-used camphorquinone (CQ). The novel findings indicate that BAPO is the most toxic among the seven PIs, but TPOL and MBF are the least toxic, directing their development and application. Combined their triggered polymer cytocompatibility and color with reported deep curing efficiency, TPOL is more promising to be applied especially to clinical practice.

A series of 1-hydroxyl-3-aminoalkoxy-thioxanthone derivatives were designed, synthesized and evaluated as potential multifunctional agents against Alzheimer's disease (AD). The results indicated that most of these compounds exhibited good AChE and MAOs inhibitory activities, significant inhibition of self- and Cu2+-induced Aβ1-42 aggregation, and moderate to good antioxidant activities. Specifically, compound 9e displayed high inhibitory potency toward AChE (IC50=0.59±0.02μM), MAO-A and MAO-B (IC50=1.01±0.02μM and 0.90±0.01μM respectively), excellent efficiency to block both self- and Cu2+-induced Aβ1-42 aggregation (74.8±1.2% and 87.7±1.9% at 25μM, respectively), good metal-chelating property and a low toxicity in SH-SY5Y cells. Furthermore, kinetic and molecular modeling studies revealed that compound 9e binds simultaneously to the catalytic active site and peripheral anionic site of AChE, and could penetrate the BBB. Collectively, these results suggested that 9e might be a potential multifunctional agent for further development in the treatment of AD.

A series of pyrene-fused thioxanthenes have been synthesized via a new concise route, and their crystal structures and photophysical properties have been fully investigated. The eight-ring fused dipyrene–thioxanthene (DPTA) can crystallize to monoclinic and triclinic X-ray structures, and their precursor has been isolated as two stable atropisomers with different photophysical properties. The EHOMO becomes higher and the Eg become narrower as more thioxanthene unit being fused with pyrene.

In this study, a thioxanthone derivative named 2-(9-oxo-9H-thioxanthen-2ylamino) acetic acid (TX-NHCH 2 COOH) was used to investigate small molecule and DNA binding interactions. Absorption and fluorescence emission spectroscopy were used and melting studies were used to explain the binding mode of TXNHCH 2 COOH-DNA. Intrinsic binding constant K b TXNHCH 2 COOH was found 6 × 10 5 M − 1 from UV–Vis absorption spectroscopy. Fluorescence emmision intensity increased by adding ct-DNA to the TXNHCH 2 COOH and KI quenching experiments resulted with low K sv value. Additionally, 3.7 °C increase for T m was observed. The observed quenching of EB and ct-DNA complex and increase viscosity values of ct-DNA by addition of TXNHCH 2 COOH was determined. All those results indicate that TXNHCH 2 COOH can intercalate into DNA base pairs. Fluorescence microscopy helped to display imaging of the TXNHCH 2 COOH-DNA solution.

Using an easily prepared triethylammonium N-benzyldithiocarbamate salt as a sulfur source, a dual C−S functionalization of cyclic diaryliodoniums to form tricyclic thioheterocycles is realized. Our method uses the readily available copper sulfate to accelerate the chemical transformation under mild conditions. A broad range of cyclic diaryliodoniums with a ring size from 5- to 7-membered can be employed to gain a quick access to tricyclic thioheterocycles including dibenzothiophenes, thioxanthenes, and phenoxathiines.

A mild and efficient system has been discovered for the synthesis of α-aryl carbonyl compounds via oxidation of benzylic C–H to C O bonds. This ultraviolet-light-mediated oxygenation reaction exhibited excellent substrate scope including various xanthenes, thioxanthenes and 9, 10-dihydroacridines and afforded the corresponding ketones with good to excellent yields under catalyst- and additive-free conditions at room temperature.

Activated 2o-allylic alcohols derived from 2-aryloxybenzaldehydes and 2-(arythio)benzaldehydes undergo intramolecular Friedel-Crafts alkylation reaction when heated with catalytic amount of a Lewis acid in 1,2-dichloroethane to provide highly E-selective 9-vinyl substituted unsymmetrical novel xanthenes and thioxanthenes in good yields.

Epigenetic information is encoded in the mammalian genome in the form of cytosines methylated at the 5 position. While cytosine methylation has multiple biological effects, including gene regulation and silencing of integrated viral DNA, currently available methods for mapping methylation sites genome-wide have severe shortcomings. For instance, the gold standard bisulfite sequencing approach suffers from the use of harsh reaction conditions resulting in DNA cleavage and incomplete conversion of unmethylated cytosine to uracil. We report here on a new photochemical method in which a DNA (cytosine-5)-methyltransferase can be used to covalently attach reactive functionalities which upon irradiation at ~350 nm initiate photoinduced intramolecular reactions that convert methylated C to T analogues. We synthesized a model compound, a cinnamyl ether-containing cytidine derivative, and demonstrated its conversion to a thymidine analogue using mild conditions and a DNA-compatible wavelength (~350 nm), enabled by the use of a triplet sensitizer, thioxanthone. Transfer of a cinnamyl ether or comparable reactive functionality from an AdoMet analog to cytosine followed by the use of this photoconversion method would require only small amounts of DNA and allow complete methylation profiling on both long and short read sequencing platforms.

Direct carbon–hydrogen bond functionalization has emerged as a powerful synthetic method for the straightforward and modular functionalization of organic molecules. In this account, we described our latest contributions in the area of oxidative sp3-carbon–hydrogen bond functionalization using mild radical oxidants for the construction of structurally important heterocycles. We have developed two new methodologies in which a new class of substrate and an uncommon nucleophilic reagent have been introduced to the existing palette of reaction partners for oxidative carbon–hydrogen functionalization. To achieve these results, the 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) radical and a benzoyl peroxide/copper(I) system have been employed as oxidants for the dehydrogenative one-pot synthesis of N-alkoxycarbonyl-protected isoxazolines from hydroxylamines and for the synthesis of dibenz[b,f]oxepines, dibenzo[b,f]thiepines, and dibenz[b,f]azepines from simple xanthenes, thioxanthenes, and acridanes, respectively. 1 Introduction 2 2,2,6,6-Tetramethylpiperidinyloxyl-Mediated Dehydrogenative Formation and Trapping of Unstable Nitrones: Synthesis of N-Alkoxycarbonyl-Protected Isoxazoline Derivatives 3 Oxidative sp3-Carbon–Hydrogen Bond Functionalization and Ring Expansion with Trimethylsilyldiazomethane: Synthesis of Dibenzoxepines, Dibenzothiepines, and Dibenzazepines 4 Conclusions and Outlook

Photoinitiators (PIs) are widely used additives in industrial polymerization process, the contamination of which through migration into foodstuffs has been subjected to increasing public scrutiny. Nevertheless, little attention has been paid to the PI residue levels and potential exposure pathways from other environmental compartments. In the present study, the occurrence of PI additives with discrete molecular structures, that is, nine benzophenones (BZPs), four thioxanthones (TXs), and eight amine co-initiators (ACIs), was investigated in commercial products, indoor dust and sewage sludge samples. Nine PI compounds were positively detected in ultraviolet curable resins with concentrations of ∑PIs (sum of the detected PIs) up to 2.51 × 10(4) ng/g, and 20 PIs can be found in food contact materials with concentrations of ∑PIs varying from 65.9 to 6.93 × 10(3) ng/g. The wide usage of PIs in commercial products led to the occurrence of 19 PIs in indoor dust, with concentrations of ∑PIs in the range of 245-5.68 × 10(3) ng/g. Meanwhile, all 21 targeted PIs could be identified in the sewage sludge, with concentrations from 67.6 to 2.03 × 10(3) ng/g. Distinct PI composition profiles were observed in different investigated compartments, and BZPs were the dominant homologues in all samples. Most of the target PIs were further identified as class III chemicals by toxic hazard estimation algorithm (Toxtree), which indicates the compounds might be of significant toxicity or have reactive functional groups.

A series of tetracyclic heterocyclic azathioxanthones were synthesized and evaluated for cell proliferations, topoisomerase inhibitions, and NCI-60 cell panel assay, respectively. Compounds 5, 7, 8, 16, and 19 were selected for topoisomerase assay after MTT assay. 7 not only showed cytotoxic effect (IC50 = 2.84 ± 0.64 μM) in PC-3 cells but also revealed topoisomerases inhibition with IC50 (10-25 μM) and increased apoptotic cleavage of PARP and caspase 3 activity. The overall of novel azathioxanthones with different cytostatic and cytotoxic activities should be further developed as new potential candidates for anticancer drugs.

The extensive use of antimicrobials is leaving medicine with few effective therapeutic options to treat many infections due to the fact that many organisms developed resistance to commonly used drugs. It is therefore pertinent to search not only for new antimicrobials but also for compounds able to restore or potentiate the activity of existing antibiotics. We have screened a library consisting of 40 (thio)xanthone derivatives for antibacterial activity and possible synergistic effects when used in combination with antibiotics. Nine out of the 40 compounds exhibited antibacterial activity against Gram-positive bacteria. Two xanthone derivatives, 1-formyl-4-hydroxy-3-methoxy (7), 2-formyl-3-hydroxy-4-methoxyxanthone (8) and the thioxanthone derivative 1-((2-(diethylamino)ethyl)amino)-4-propoxythioxanthone (10) and its hydrochloride form 13, showed activity against a methicillin-resistant Staphylococcus aureus (MRSA) isolate with minimum inhibitory concentration (MIC) values lower than 256 μg/ml. Thioxanthone 10 demonstrated antibacterial activity and also synergy when combined with ampicillin and oxacillin against MRSA. Additionally, thioxanthone 1-(piperidin-1-yl)-4-propoxythioxanthone (9), despite not having antibacterial activity presented remarkable synergy with oxacillin against MRSA; the MIC of tioxanthone 9 and oxacillin when both were in combination were 128 and 8 μg/ml, respectively. Thioxanthones 9 and 10 were also found to be synergistic when both were combined. Subsequently, docking simulations between thioxanthones 9 and 10 and the allosteric domain of penicillin-binding protein 2A (PBP2A) were undertaken in AutoDock Vina. Both compounds had the ability to bind with an allosteric domain of PBP2A, which may explain their synergy with oxacillin. These two thioxanthone derivatives with different profiles may be promising tools for restoring the activity of oxacillin against MRSA.

A novel one-component type II polymeric photoinitiator, poly(vinyl alcohol)-thioxanthone (PVA-TX), is synthesized by a simple acetalization process and characterized. PVA-TX enables photopolymerization of methyl methacrylate and acrylamide in both organic and aqueous media. Photopolymerization proceeds even in the absence of a co-initiator since PVA-TX possesses both chromophoric and hydrogen donating sites in the structure.

9H-Thioxanthen-9-ones are an important class of compound and are a common heterocyclic scaffold in biologically active and medicinally significant compounds. In this paper the synthesis of 1-fluoro-4-methyl-9H-thioxanthen-9-one and some amine derivatives labeled with carboxyl-14 is described.

In this study, the involvement of ataxia telangiectasia mutated (ATM) kinase and heat shock protein 90 (HSP90) in endothelial nitric oxide synthase (eNOS) activation was investigated in X-irradiated bovine aortic endothelial cells. The activity of nitric oxide synthase (NOS) and the phosphorylation of serine 1179 of eNOS (eNOS-Ser1179) were significantly increased in irradiated cells. The radiation-induced increases in NOS activity and eNOS-Ser1179 phosphorylation levels were significantly reduced by treatment with either an ATM inhibitor (Ku-60019) or an HSP90 inhibitor (geldanamycin). Geldanamycin was furthermore found to suppress the radiation-induced phosphorylation of ATM-Ser1181. Our results indicate that the radiation-induced eNOS activation in bovine aortic endothelial cells is regulated by ATM and HSP90.

Thioxanthone and its derivatives are the most remarkable molecules due to their vast variety of application such as radiation curing that is, until using them as a therapeutic drug. Therefore, in this study it was intended to use 2-Thioxanthone acetic acid with and without NaCl in Tris HCl buffer solution (pH:7.0) to represent the interaction with ct-DNA. The UV–vis absorption spectra of TXCH2COOH in the presence of ct-DNA showed hypochromism and the intrinstic binding constant (Kb) was determined as 6 × 103 L mol−1. The fluoresence intensity of TXCH2COOH with ct-DNA clearly increased up to 101% which indicated that the fluorescence intensity was very sensitive to ct-DNA concentration. The binding constant (K) and the values of number of binding sites (n) and were calculated as 1.8 × 103 L mol−1 and 0.69, respectively. When the quenching constants (Ksv) of free TXCH2COOH and TXCH2COOH, which were bonded with ct-DNA were compared, slightly changed values of Ksv were seen. Moreover, displacement assay with Hoechst 33,258 and viscosity measurements in the presence and absence of NaCl salt also confirmed the binding mode which noted the electrostatic interaction following groove binding between TXCH2COOH and ct-DNA. Last but not least, the salt effect was examined on ct-DNA binding with TXCH2COOH. The results of the experiments indicated that the groove binding was strengthened by NaCl whereas in the high NaCl concentration, the binding ability of TXCH2COOH to ct-DNA was inversely affected.

International audience; DNA glycosylases are emerging as relevant pharmacological targets in inflammation, cancer and neurodegenerative diseases. Consequently, the search for inhibitors of these enzymes has become a very active research field. As a continuation of previous work that showed that 2-thioxanthine (2TX) is an irreversible inhibitor of zinc finger (ZnF)-containing Fpg/Nei DNA glycosylases, we designed and synthesized a mini-library of 2TX-derivatives (TXn) and evaluated their ability to inhibit Fpg/Nei enzymes. Among forty compounds, four TXn were better inhibitors than 2TX for Fpg. Unexpectedly, but very interestingly, two dithiolated derivatives more selectively and efficiently inhibit the zincless finger (ZnLF)-containing enzymes (human and mimivirus Neil1 DNA glycosylases hNeil1 and MvNei1, respectively). By combining chemistry, biochemistry, mass spectrometry, blind and flexible docking and X-ray structure analysis, we localized new TXn binding sites on Fpg/Nei enzymes. This endeavor allowed us to decipher at the atomic level the mode of action for the best TXn inhibitors on the ZnF-containing enzymes. We discovered an original inhibition mechanism for the ZnLF-containing Fpg/Nei DNA glycosylases by disulfide cyclic trimeric forms of dithiopurines. This work paves the way for the design and synthesis of a new structural class of inhibitors for selective pharmacological targeting of hNeil1 in cancer and neurodegenerative diseases.

In vitro studies showed that 1-(propan-2-ylamino)-4-propoxy-9H-thioxanthen-9-one (TX5) increases P-glycoprotein (P-gp) expression and activity in Caco-2 cells, preventing xenobiotic toxicity. The present study aimed at investigating TX5 effects on P-gp expression/activity using Wistar Han rats: a) in vivo, evaluating intestinal P-gp activity; b) ex vivo, evaluating P-gp expression in ileum brush border membranes (BBM) and P-gp activity in everted intestinal sacs; c) ex vivo, evaluating P-gp activity in everted intestinal sacs of the distal and proximal ileum. TX5 (30 mg/kg, b.w.), gavage, activated P-gp in vivo, given the significant decrease in the AUC of digoxin (0.25 mg/kg, b.w.). The efflux of rhodamine 123 (300 μM), a P-gp fluorescent substrate, significantly increased in TX5-treated everted sacs from the distal portion of the rat ileum, when P-gp activity was evaluated in the presence of TX5 (20 μM), an effect abolished by the P-gp inhibitor verapamil (100 μM). No increases on P-gp expression or activity were found in TX5-treated BBM of the distal ileum and everted distal sacs, respectively, 24 h after TX5 (10 mg/kg, b.w.) administration. In vivo, no differences were found on digoxin portal concentration between control (digoxin 0.025 mg/kg, b.w., intraduodenal) and TX5-treated (digoxin+TX5 20 μM, intraduodenal) rats. The observed discrepancies in digoxin results can be related to differences in TX5 dose administered and used methodologies. Thus, the results show that TX5 activates P-gp at the distal portion of the rat ileum, and, at the higher dose tested (30 mg/kg, b.w.), seems to modulate in vivo the AUC of P-gp substrates. Fil: Rocha-Pereira, Carolina. Universidad de Porto; Portugal Fil: Ghanem, Carolina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Investigaciones Farmacológicas; Argentina Fil: Silva, Renata. Universidad de Porto; Portugal Fil: Casanova, Alfredo G.. Universidad de Salamanca; España Fil: Duarte Araújo, Margarida. Universidad de Porto; Portugal Fil: Gonçalves Monteiro, Salomé. Universidad de Porto; Portugal Fil: Sousa, Emília. Universidad de Porto; Portugal Fil: Bastos, Maria de Lourdes. Universidad de Porto; Portugal Fil: Remião, Fernando. Universidad de Porto; Portugal

The experimental FT-IR and FT-Raman spectra of 9-[3-(Dimethylamino)propy1]-2-trifluoro-methyl-9H-thioxanthen-9-ol have been recorded. Quantum chemical calculations of geometry and vibrational wavenumbers of 9-[3-(Dimethylamino)propyl-2-trifluoro-methyl-9H-thioxanthen-9-ol are carried out theoretically. Four possible stable conformations of the title compound were determined. In terms of the conformational analysis, one of the most interesting structural features of the title compound is the intra molecular O-H center dot center dot center dot N hydrogen bond. The barrier of planarity between the most stable and planar form is also predicted. The optimized geometrical parameters obtained by B3LYP method show a good agreement with XRD data. The difference between the observed and theoretical wavenumbers is very small. The complete assignments were performed on the basis of potential energy distribution of the vibrational modes calculated theoretically. The calculated HOMO and LUMO energies allow the calculation of atomic and molecular properties and they also showed that charge transfer occurs in the molecule. A detailed molecular picture of the title compound and its interactions were obtained from NBO analysis. As seen from the MEP map, negative potential regions are over the hydroxyl group and positive potential regions are over the methyl groups. (C) 2014 Elsevier B.V. All rights reserved.

The induction of P-glycoprotein (P-gp), an ATP-dependent efflux pump, has been proposed as a strategy against the toxicity induced by P-gp substrates such as the herbicide paraquat (PQ). The aim of this study was to screen five newly synthetized thioxanthonic derivatives, a group known to interact with P-gp, as potential inducers of the pump's expression and/or activity and to evaluate whether they would afford protection against PQ-induced toxicity in Caco-2 cells. All five thioxanthones (20 µM) caused a significant increase in both P-gp expression and activity as evaluated by flow cytometry using the UIC2 antibody and rhodamine 123, respectively. Additionally, it was demonstrated that the tested compounds, when present only during the efflux of rhodamine 123, rapidly induced an activation of P-gp. The tested compounds also increased P-gp ATPase activity in MDR1-Sf9 membrane vesicles, indicating that all derivatives acted as P-gp substrates. PQ cytotoxicity was significantly reduced in the presence of four thioxanthone derivatives, and this protective effect was reversed upon incubation with a specific P-gp inhibitor. In silico studies showed that all the tested thioxanthones fitted onto a previously described three-feature P-gp induction pharmacophore. Moreover, in silico interactions between thioxanthones and P-gp in the presence of PQ suggested that a co-transport mechanism may be operating. Based on the in vitro activation results, a pharmacophore model for P-gp activation was built, which will be of further use in the screening for new P-gp activators. In conclusion, the study demonstrated the potential of the tested thioxanthonic compounds in protecting against toxic effects induced by P-gp substrates through P-gp induction and activation.

Multilayer print designs are commonly used in commercial food packaging to attract consumers. UV-curable ink is generally used in this type of printing due to its ease of application, space saving, and rapid drying; however, there have been a number of health alerts related to the contamination of food by photoinitiators in UV-curable ink. In this study, we established a multi-analyte method by which to detect 30 photoinitiators simultaneously. We then applied this method to the analysis of five breakfast cereals and ten types of packaged juice to detect the presence of photoinitiator contamination. Sample treatment was performed using the QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the extraction of photoinitiators. Chromatographic separation of two isomers, methylbenzophenone (MBP) and isopropylthioxanthone (ITX), was achieved using a pentafluorophenyl propyl (PFP) column (1.7 µm, 100 × 2.1 mm i.d.) and MeOH: 5 mM formic acid–ammonium formate (pH 4.0) in gradient elution. The average recovery of photoinitiators from cereal was between 62.0 and 120.3%, with a coefficient of variation between 0.4 and 14.4%. The average recovery of photoinitiators from packaged juices was between 84.4 and 122.9% with a coefficient of variation between 0.5 and 9.5%. The contamination results were as follows: 13.1 ng/g triphenyl phosphate (TPP) was detected in one breakfast cereal, and 2-hydroxy-4-methoxy benzophenone (BP-3), 1-hydroxycyclohexyl phenyl-ketone (Irgacure 184), methyl-2-benzoylbenzoate (MOBB), and 2,4-diethyl-9H-thioxanthen-9-one (DETX) were detected in one of the packaged juices at levels ranging from 2.2 to 152.9 ng/g.

Acetic acid-based thioxanthone (TXCH2 COOH) was synthesized and characterized and used as a photoinitiator for free radical photopolymerization of methyl methacrylate (MMA) in the absence and presence of a tertiary amine (MDEA) in different solvents. Different absorption properties were observed depending on the solvent. Fluorescence and phosphorescence experiments were also carried out successfully. The fluorescence quantum yield was found to be 0.09 and the phosphorescence lifetime was calculated as 138 ms at 77 K. The photoinitiator undergoes efficient intersystem crossing into the triplet state and the lowest triplet state possesses π-π* configuration. Laser flash photolysis experiments show that transient absorption of TXCH2 COOH is similar to the parent thioxanthone and the triplet lifetime was calculated as 2.3 μs at 630 nm.

The oncogenic nature ascribed to the PIM-2 kinase relies mostly on phosphorylation of substrates that act as pro-survival/anti-apoptotic factors. Nevertheless, pro-survival effects can also result from activating DNA repair mechanisms following damage. In this study, we addressed the possibility that PIM-2 plays a role in the cellular response to UV damage, an issue that has never been addressed before. We found that in U2OS cells, PIM-2 expression and activity increased upon exposure to UVC radiation (2–50 mJ/cm2), and Pim-2-silenced cells were significantly more sensitive to UV radiation. Overexpression of PIM-2 accelerated removal of UV-induced DNA lesions over time, reduced γH2AX accumulation in damaged cells, and rendered these cells significantly more viable following UV radiation. The protective effect of PIM-2 was mediated by increased E2F-1 and activated ATM levels. Silencing E2F-1 reduced the protective effect of PIM-2, whereas inhibiting ATM activity abrogated this protective effect, irrespective of E2F-1 levels. The results obtained in this study place PIM-2 upstream to E2F-1 and ATM in the UV-induced DNA damage response. Background: The PIM-2 kinase is a potent survival factor; its role in the DNA damage response has never been addressed. Results: PIM-2 promotes DNA lesions repair in an E2F-1 and ATM-dependent manner; Pim-2-silenced cells are more susceptible to UV damage. Conclusion: PIM-2 is an upstream activator of E2F-1 and ATM in the UV damage response. Significance: PIM-2 is an essential component of the UV damage response.

Purpose: Glioblastoma multiforme (GBM) is the most lethal form of brain cancer with a median survival of only 12 to 15 months. Current standard treatment consists of surgery followed by chemoradiation. The poor survival of patients with GBM is due to aggressive tumor invasiveness, an inability to remove all tumor tissue, and an innate tumor chemo- and radioresistance. Ataxia–telangiectasia mutated (ATM) is an excellent target for radiosensitizing GBM because of its critical role in regulating the DNA damage response and p53, among other cellular processes. As a first step toward this goal, we recently showed that the novel ATM kinase inhibitor KU-60019 reduced migration, invasion, and growth, and potently radiosensitized human glioma cells in vitro. Experimental Design: Using orthotopic xenograft models of GBM, we now show that KU-60019 is also an effective radiosensitizer in vivo. Human glioma cells expressing reporter genes for monitoring tumor growth and dispersal were grown intracranially, and KU-60019 was administered intratumorally by convection-enhanced delivery or osmotic pump. Results: Our results show that the combined effect of KU-60019 and radiation significantly increased survival of mice 2- to 3-fold over controls. Importantly, we show that glioma with mutant p53 is much more sensitive to KU-60019 radiosensitization than genetically matched wild-type glioma. Conclusions: Taken together, our results suggest that an ATM kinase inhibitor may be an effective radiosensitizer and adjuvant therapy for patients with mutant p53 brain cancers. Clin Cancer Res; 19(12); 3189–200. ©2013 AACR.

Serotonin [5-hydroxytryptamine (5-HT)] is released from enterochromaffin cells in the mucosa of the small intestine. We tested a hypothesis that elevation of 5-HT in the environment of enteric mast cells might degranulate the mast cells and release mediators that become paracrine signals to the enteric nervous system, spinal afferents, and secretory glands. Western blotting, immunofluorescence, ELISA, and pharmacological analysis were used to study expression of 5-HT receptors by mast cells in the small intestine and action of 5-HT to degranulate the mast cells and release histamine in guinea pig small intestine and segments of human jejunum discarded during Roux-en-Y gastric bypass surgeries. Mast cells in human and guinea pig preparations expressed the 5-HT1A receptor. ELISA detected spontaneous release of histamine in guinea pig and human preparations. The selective 5-HT1A receptor agonist 8-hydroxy-PIPAT evoked release of histamine. A selective 5-HT1A receptor antagonist, WAY-100135, suppressed stimulation of histamine release by 5-HT or 8-hydroxy-PIPAT. Mast cell-stabilizing drugs, doxantrazole and cromolyn sodium, suppressed the release of histamine evoked by 5-HT or 8-hydroxy-PIPAT in guinea pig and human preparations. Our results support the hypothesis that serotonergic degranulation of enteric mast cells and release of preformed mediators, including histamine, are mediated by the 5-HT1A serotonergic receptor. Association of 5-HT with the pathophysiology of functional gastrointestinal disorders (e.g., irritable bowel syndrome) underlies a question of whether selective 5-HT1A receptor antagonists might have therapeutic application in disorders of this nature.

Vasoactive intestinal polypeptide (VIP) has been implicated as a regulator of intestinal barrier function and inflammation. Our aim was to elucidate the role of VIP in follicle-associated epithelium (FAE) and villus epithelium (VE) permeability following stress in rats and on human intestinal barrier function.Rats were injected intraperitoneally (i.p.) with VIP receptor-antagonists (anti-VPACs), a mast cell stabilizer, doxantrazole (DOX), or NaCl, and submitted to acute water avoidance stress. Ileal segments were mounted in Ussing chambers to assess (51) chromium-edta ((51) Cr-edta) and Escherichia (E.) coli (strain K-12) permeability. Rat ileal and human ileal and colonic segments were exposed to VIP ± anti-VPACs or DOX. An in vitro co-culture model of human FAE was used to study epithelial-VIP effects. VIP/VPACs distribution was assessed by microscopy.Stress increased (51) Cr-edta and E. coli permeability in VE and FAE. The increases were abolished by i.p. injection of DOX or anti-VPACs. Ileal VIP-exposure ex vivo increased bacterial passage and this was reduced by DOX. In human FAE ex vivo, VIP treatment doubled bacterial uptake, which was normalized by DOX or anti-VPACs. No barrier effects were observed in human colonic tissue. VPACs were found in rat and human ileal follicles, with partial mast cell co-localization. The co-culture model confirmed VIP-mast cell-epithelial interactions in the regulation of barrier function.Stress affects the FAE barrier by mechanisms involving VIP and VPACs on mucosal mast cells. We suggest a regulatory role for VIP in the control of ileal permeability that may be relevant to bacterial-epithelial interactions in stress-related intestinal disorders.

In recent years, various biological processes have been found to be regulated by miRNA-mediated gene silencing. A small molecule that modulate the miRNA pathway will provide the biological tool for elucidating mechanisms of miRNA-mediated gene regulation, and can be the drug lead for miRNA related diseases. In this study, we demonstrated that an aminoalkoxy-substituted thioxanthone derivative interferes Dicer-mediated processing of pre-miRNA. Information about the interaction between these xanthone derivatives and pre-miRNAs will enable us to design and develop new small molecule-based inhibitors for miRNA pathway.

OBJECTIVE: Intestinal inflammation resulting from manipulation-induced mast cell activation is a crucial mechanism in the pathophysiology of postoperative ileus (POI). Recently it has been shown that spleen tyrosine kinase (Syk) is involved in mast cell degranulation. Therefore, we have evaluated the effect of the Syk-inhibitor GSK compound 143 (GSK143) as potential treatment to shorten POI. DESIGN: In vivo: in a mouse model of POI, the effect of the Syk inhibitor (GSK143) was evaluated on gastrointestinal transit, muscular inflammation and cytokine production. In vitro: the effect of GSK143 and doxantrazole were evaluated on cultured peritoneal mast cells (PMCs) and bone marrow derived macrophages. RESULTS: In vivo: intestinal manipulation resulted in a delay in gastrointestinal transit at t=24 h (Geometric Center (GC): 4.4±0.3). Doxantrazole and GSK143 significantly increased gastrointestinal transit (GC doxantrazole (10 mg/kg): 7.2±0.7; GSK143 (1 mg/kg): 7.6±0.6), reduced inflammation and prevented recruitment of immune cells in the intestinal muscularis. In vitro: in PMCs, substance P (0-90 μM) and trinitrophenyl (0-4 μg/ml) induced a concentration-dependent release of β-hexosaminidase. Pretreatment with doxantrazole and GSK143 (0.03-10 μM) concentration dependently blocked substance P and trinitrophenyl induced β-hexosaminidase release. In addition, GSK143 was able to reduce cytokine expression in endotoxin-treated bone marrow derived macrophages in a concentration-dependent manner. CONCLUSIONS: The Syk inhibitor GSK143 reduces macrophage activation and mast cell degranulation in vitro. In addition, it inhibits manipulation-induced intestinal muscular inflammation and restores intestinal transit in mice. These findings suggest that Syk inhibition may be a new tool to shorten POI. ispartof: Gut vol:62 issue:11 pages:1581-90 ispartof: location:England status: published

International audience; A new type of photoinitiator for free radical polymerization was synthesized and characterized. 2-(11-Mercaptoundecyloxy)thioxanthone (1) was anchored at the surface of silver nanoparticles (NPs), and the interaction of plasmon field generated in the immediate vicinity of Ag NPs carrying the chromophores was evaluated. The optical features and structure of the silver-initiator nanoassemblies (Ag@1) were characterized by UV-vis and fluorescence spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). TEM and XRD studies revealed the presence of ca. 5-6 nm diameter Ag NPs, and XPS also confirmed the successful anchorage of 1 at their periphery. The nanoassemblies Ag@1 were successfully used as macroinitiator for radical polymerization of acrylate monomers, triggered photochemically, to obtain Ag(0)-polyacrylate nanocomposite materials. The nanocomposite materials synthesized with the use of Ag@1 exhibit attractive possibilities for patterning the surface of thin films.

The purpose of this study was to evaluate the reactivity and polymerization kinetics behavior of a model dental adhesive resin with water-soluble initiator systems.A monomer blend based on Bis-GMA, TEGDMA and HEMA was used as a model dental adhesive resin, which was polymerized using a thioxanthone type (QTX) as a photoinitiator. Binary and ternary photoinitiator systems were formulated using 1mol% of each initiator. The co-initiators used in this study were ethyl 4-dimethylaminobenzoate (EDAB), diphenyliodonium hexafluorophosphate (DPIHFP), 1,3-diethyl-2-thiobarbituric acid (BARB), p-toluenesulfinic acid and sodium salt hydrate (SULF). Absorption spectra of the initiators were measured using a UV-Vis spectrophotometer, and the photon absorption energy (PAE) was calculated. The binary system camphorquinone (CQ)/amine was used as a reference group (control). Twelve groups were tested in triplicate. Fourier-transform infrared spectroscopy (FTIR) was used to investigate the polymerization reaction during the photoactivation period to obtain the degree of conversion (DC) and maximum polymerization rate (R(p)(max)) profile of the model resin.In the analyzed absorption profiles, the absorption spectrum of QTX is almost entirely localized in the UV region, whereas that of CQ is in the visible range. With respect to binary systems, CQ+EDAB exhibited higher DC and R(p)(max) values. In formulations that contained ternary initiator systems, the group CQ+QTX+EDAB was the only one of the investigated experimental groups that exhibited an R(p)(max) value greater than that of CQ+EDAB. The groups QTX+EDAB+DPIHFP and QTX+DPIHFP+SULF exhibited values similar to those of CQ+EDAB with respect to the final DC; however, they also exhibited lower reactivity.Water-soluble initiator systems should be considered as alternatives to the widely used CQ/amine system in dentin adhesive formulations.

A series of xanthone and thioxanthone derivatives with aminoalkoxy substituents were synthesized as fluorescent indicators for a displacement assay in the study of small-molecule-RNA interactions. The RNA-binding properties of these molecules were investigated in terms of the improved binding selectivity to the loop region in the RNA secondary structure relative to 2,7-bis(2-aminoethoxy)xanthone (X2S) by fluorimetric titration and displacement assay. An 11-mer double-stranded RNA and a hairpin RNA mimicking the stem loop IIB of Rev response element (RRE) RNA of HIV-1 mRNA were used. The X2S derivatives with longer aminoalkyl substituents showed a higher affinity to the double-stranded RNA than the parent molecule. Introduction of a methyl group on the aminoethoxy moiety of X2S effectively modulated the selectivity to the RNA secondary structure. Methyl group substitution at the C1' position suppressed the binding to the loop regions. Substitution with two methyl groups on the amino nitrogen atom resulted in reducing the affinity to the double-stranded region by a factor of 40%. The effect of methyl substitution on the amino nitrogen atom was also observed for a thioxanthone derivative. Titration experiments, however, suggested that thioxanthone derivatives showed a more prominent tendency of multiple binding to RNA than xanthone derivatives. The selectivity index calculated from the affinity to the double-stranded and loop regions suggested that the N,N-dimethyl derivative of X2S would be suitable for the screening of small molecules binding to RRE.

For many pathologies, there is a crescent effort to design multiple ligands that interact with a wide variety of targets. 1-Aminated thioxanthone derivatives were synthesized and assayed for their in vitro dual activity as antitumor agents and P-glycoprotein (P-gp) inhibitors. The approach was based on molecular hybridization of a thioxanthone scaffold, present in known antitumor drugs, and an amine, described as an important pharmacophoric feature for P-gp inhibition. A rational approach using homology modeling and docking was used, to select the molecules to be synthesized by conventional or microwave-assisted Ullmann C–N cross-coupling reaction. The obtained aminated thioxanthones were highly effective at inhibiting P-gp and/or causing growth inhibition in a chronic myelogenous leukemia cell line, K562. Six of the aminated thioxanthones had GI 50 values in the K562 cell line below 10 μM and 1-{[2-(diethylamino)ethyl]amino}-4-propoxy-9 H -thioxanthen-9-one ( 37 ) had a GI 50 concentration (1.90 μM) 6-fold lower than doxorubicin (11.89 μM) in the K562Dox cell line. The best P-gp inhibitor found was 1-[2-(1 H -benzimidazol-2-yl)ethanamine]-4-propoxy-9 H -thioxanthen-9-one ( 45 ), which caused an accumulation rate of rhodamine-123 similar to that caused by verapamil in the K562Dox resistant cell line, and a decrease in ATP consumption by P-gp. At a concentration of 10 μM, compound 45 caused a decrease of 12.5-fold in the GI 50 value of doxorubicin in the K562Dox cell line, being 2-fold more potent than verapamil. From the overall results, the aminated thioxanthones represent a new class of P-gp inhibitors with improved efficacy in sensitizing a resistant P-gp overexpressing cell line (K562Dox) to doxorubicin.

Inflammation and oxidative stress are linked to the deleterious effects of cigarette smoke in producing chronic obstructive pulmonary disease (COPD). Myeloperoxidase (MPO), a neutrophil and macrophage product, is important in bacterial killing, but also drives inflammatory reactions and tissue oxidation.To determine the role of MPO in COPD.We treated guinea pigs with a 2-thioxanthine MPO inhibitor, AZ1, in a 6-month cigarette smoke exposure model, with one group receiving compound from Smoking Day 1 and another group treated after 3 months of smoke exposure.At 6 months both treatments abolished smoke-induced increases in lavage inflammatory cells, largely ameliorated physiological changes, and prevented or stopped progression of morphologic emphysema and small airway remodeling. Cigarette smoke caused a marked increase in immunohistochemical staining for the myeloperoxidase-generated protein oxidation marker dityrosine, and this effect was considerably decreased with both treatment arms. Serum 8-isoprostane, another marker of oxidative stress, showed similar trends. Both treatments also prevented muscularization of the small intrapulmonary arteries, but only partially ameliorated smoke-induced pulmonary hypertension. Acutely, AZ1 prevented smoke-induced increases in expression of cytokine mediators and nuclear factor-κB binding.We conclude that an MPO inhibitor is able to stop progression of emphysema and small airway remodeling and to partially protect against pulmonary hypertension, even when treatment starts relatively late in the course of long-term smoke exposure, suggesting that inhibition of MPO may be a novel and useful therapeutic treatment for COPD. Protection appears to relate to inhibition of oxidative damage and down-regulation of the smoke-induced inflammatory response.

Fluorination of fluorophores can substantially enhance their photostability and improve spectroscopic prop- erties. To facilitate access to fluorinated fluorophores, bis- (2,4,5-trifluorophenyl)methanone was synthesized by treatment of 2,4,5-trifluorobenzaldehyde with a Grignard reagent derived from 1-bromo-2,4,5-trifluorobenzene, followed by oxidation of the resulting benzyl alcohol. This hexafluorobenzophenone was subjected to sequential nucleophilic aromatic substitution reactions, first at one or both of the more reactive 4,4!-fluorines, and second by cyclization through substitution of the less reactive 2,2!-fluorines, using a variety of oxygen, nitrogen, and sulfur nucleophiles, including hydroxide, methoxide, amines, and sulfide. This method yields symmetrical and asymmetrical fluorinated benzophenones, xanthones, acridones, and thioxanthones and provides scalable access to known and novel precursors to fluorinated analogues of fluorescein, rhodamine, and other derivatives. Spectroscopic studies revealed that several of these precursors are highly fluorescent, with tunable absorption and emission spectra, depending on the substituents. This approach should allow access to a wide variety of novel fluorinated fluorophores and related compounds.