40 research outputs found

    Potent Apoptotic Response Induced by Chloroacetamidine Anthrathiophenediones in Bladder Cancer Cells.

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    We previously found that two neighboring G-quadruplexes behave as a molecular switch controlling the expression of HRAS (Cogoi, S.; Schekotikhin, A. E.; Xodo, L. E. Nucl. Acids Res. 2014, DOI: 10.1093/nar/gku574). In this study we have designed anthrathiophenediones with two hloroacetamidine-containing side chains (CATDs) as G-quadruplex binders and have examined their anticancer activity in T24 bladder cancer cells bearing mutant HRAS and in T24 xenografts. The designed CATDs (3a 12e), bearing alkyl side chains of different length, penetrate T24 cancer cells more than their analogues with guanidine-containing side chains. The lead compounds 3a and 3c inhibit HRAS expression, metabolic activity, and colony formation in T24 cancer cells. They also activate a strong apoptotic response, as indicated by PARP-1, caspases 3/7, and annexin V/propidium iodide assays. Apoptosis occurs under conditions where cyclin D1 is down-regulated and the cell cycle arrested in G2 phase. Finally, compound 3a inhibits the growth of T24 xenografts and increases the median survival time of nude mice

    Стандартные образцы состава фармацевтических субстанций противомикробных препаратов

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    The present study aims to generalize the experience of creating state reference materials (GSOs) of active substances and determine their main characteristics, standardized both in the State Pharmacopoeia of the Russian Federation and in the regulatory documents of the measurement uniformity assurance system. In connection with the violation of supply chains, the acquisition and use of foreign reference active substances became quite problematic or even impossible. As a consequence of the current difficult situation with the insufficient nomenclature of GSOs, the domestic manufacturers and developers faced urgent problems in creating them. The development of antimicrobial reference active substances will solve urgent issues of strengthening the technological sovereignty of Russia, minimize the import dependence of the Russian economy, as well as ensure the targets of the Strategy for Scientific and Technological Development of the Russian Federation to be achieved. The conclusions of the study can be applied in creating GSOs to substitute imported reference materials or surpass their level.В настоящее время в связи с нарушением цепей поставок стало довольно проблематично, а зачастую невозможно приобретение и использование стандартных образцов фармацевтических субстанций зарубежного производства. Как следствие сложившейся непростой ситуации с недостаточной номенклатурой стандартных образцов утвержденного типа (ГСО) перед производителями и разработчиками ГСО встали неотложные задачи создания таких ГСО. Разработка стандартных образцов состава фармацевтических субстанций противомикробных препаратов позволит решить насущные вопросы укрепления технологического суверенитета России, минимизировать импортозависимость отраслей российской экономики, обеспечит достижение целевых показателей Стратегии научно-технологического развития Российской Федерации. Настоящее исследование призвано обобщить опыт создания ГСО фармацевтических субстанций и определения их основных характеристик, нормируемых как в Государственной Фармакопее Российской Федерации, так и в нормативных документах системы обеспечения единства измерений. Основная значимость исследования состоит в применении приведенных в работе выводов для создания современных ГСО, способных не просто импортозаместить стандартные образцы зарубежного производства, а и временами опередить другие страны

    Induced production of antifungal naphthoquinones in the pitchers of the carnivorous plant Nepenthes khasiana

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    Nepenthes spp. are carnivorous plants that have developed insect capturing traps, evolved by specific modification of the leaf tips, and are able to utilize insect degradation products as nutritional precursors. A chitin-induced antifungal ability, based on the production and secretion to the trap liquid of droserone and 5-O-methyldroserone, is described here. Such specific secretion uniquely occurred when chitin injection was used as the eliciting agent and probably reflects a certain kind of defence mechanism that has been evolved for protecting the carnivory-based provision of nutritional precursors. The pitcher liquid containing droserone and 5-O-methyldroserone at 3:1 or 4:1 molar ratio, as well as the purified naphthoquinones, exerted an antifungal effect on a wide range of plant and human fungal pathogens. When tested against Candida and Aspergillus spp., the concentrations required for achieving inhibitory and fungicidal effects were significantly lower than those causing cytotoxicity in cells of the human embryonic kidney cell line, 293T. These naturally secreted 1,4-naphthoquinone derivatives, that are assumed to act via semiquinone enhancement of free radical production, may offer a new lead to develop alternative antifungal drugs with reduced selectable pressure for potentially evolved resistance

    Novel Photosensitizers Trigger Rapid Death of Malignant Human Cells and Rodent Tumor Transplants via Lipid Photodamage and Membrane Permeabilization

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    BACKGROUND: Apoptotic cascades may frequently be impaired in tumor cells; therefore, the approaches to circumvent these obstacles emerge as important therapeutic modalities. METHODOLOGY/PRINCIPAL FINDINGS: Our novel derivatives of chlorin e(6), that is, its amide (compound 2) and boronated amide (compound 5) evoked no dark toxicity and demonstrated a significantly higher photosensitizing efficacy than chlorin e(6) against transplanted aggressive tumors such as B16 melanoma and M-1 sarcoma. Compound 5 showed superior therapeutic potency. Illumination with red light of mammalian tumor cells loaded with 0.1 µM of 5 caused rapid (within the initial minutes) necrosis as determined by propidium iodide staining. The laser confocal microscopy-assisted analysis of cell death revealed the following order of events: prior to illumination, 5 accumulated in Golgi cysternae, endoplasmic reticulum and in some (but not all) lysosomes. In response to light, the reactive oxygen species burst was concomitant with the drop of mitochondrial transmembrane electric potential, the dramatic changes of mitochondrial shape and the loss of integrity of mitochondria and lysosomes. Within 3-4 min post illumination, the plasma membrane became permeable for propidium iodide. Compounds 2 and 5 were one order of magnitude more potent than chlorin e(6) in photodamage of artificial liposomes monitored in a dye release assay. The latter effect depended on the content of non-saturated lipids; in liposomes consisting of saturated lipids no photodamage was detectable. The increased therapeutic efficacy of 5 compared with 2 was attributed to a striking difference in the ability of these photosensitizers to permeate through hydrophobic membrane interior as evidenced by measurements of voltage jump-induced relaxation of transmembrane current on planar lipid bilayers. CONCLUSIONS/SIGNIFICANCE: The multimembrane photodestruction and cell necrosis induced by photoactivation of 2 and 5 are directly associated with membrane permeabilization caused by lipid photodamage

    Ligands of G-quadruplex nucleic acids

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    Addition reactions of fluoroalkenes

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    Evaluation of Toxic Properties of New Glycopeptide Flavancin on Rats

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    Glycopeptide antibiotics have side effects that limit their clinical use. In view of this, the development of glycopeptides with improved chemotherapeutic properties remains the main direction in the search for new antibacterial drugs. The objective of this study was to evaluate the toxicological characteristics of new semi-synthetic glycopeptide flavancin. Acute and chronic toxicity of antibiotic was evaluated in Wistar rats. The medium lethal dose (LD50) and the maximum tolerated doses (MTD) were calculated by the method of Litchfield and Wilcoxon. In the chronic toxicity study, the treatment regimen consisted of 15 daily intraperitoneal injections using two dosage levels: 6 and 10 mg/kg/day. Total doses were equivalent to MTD or LD50 of flavancin, respectively. The study included assessment of the body weight, hematological parameters, blood biochemical parameters, urinalysis, and pathomorphological evaluation of the internal organs. The results of the study demonstrated that no clinical-laboratory signs of toxicity were found after 15 daily injections of flavancin at a total dose close to the MTD or LD50. The pathomorphological study did not reveal any lesions on the organ structure of animals after low-dose administration of flavancin. Thus, flavancin favorably differs in terms of toxicological properties from the glycopeptides currently used in the clinic

    The first series of 4,11-bis[(2-aminoethyl)amino]anthra[2,3-b]furan-5,10-diones: Synthesis and anti-proliferative characteristics

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    We developed the synthesis of a series of furan-fused tetracyclic analogues of the antitumor agent ametantrone. The reactions included nucleophilic substitution of propoxy groups in 4,11-dipropoxyanthra[2,3-b]furan-5,10-diones with ethylenediamines, producing the derivatives of 4,11-diaminoanthra[2,3-b]furan-5,10-dione in good yields. Studies of anti-proliferative activity on a panel of mammalian tumor cell lines demonstrated that anthra[2,3-b]furan-5,10-diones were the most potent derivatives among heteroarene-fused ametantrone analogues with one heteroatom. We identified several compounds that evoked a growth inhibitory effect at submicromolar concentrations. The anthra[2,3-b]furan-5,10-dione 9 with distal methylamino groups was markedly potent against drug-resistant cell lines with P-glycoprotein overexpression or p53 gene deletion. Furthermore, this derivative attenuated in vitro topoisomerase I-mediated DNA uncoiling at low micromolar concentrations. These results demonstrate that anthrafurandiones are a new class of heterocyclic anthraquinone derivatives with the properties potentially valuable for anticancer therapy.status: publishe
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