Publications by authors named "Zbigniew J Witczak"

The conjugate N-adducts of thio-1,3,4-diazole and 2-thiazoline with levoglucosenone were synthesized via a stereoselective, base-catalyzed conjugate N-Michael addition to levoglucosenone at C-4. Structural assignments were established using 1H and 13C NMR analysis, and X-ray single-crystal analysis for one of the compounds. The biological properties of the novel compounds were tested on a cell model.

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The in situ-generated -aryl nitrile imines derived from trifluoroacetonitrile smoothly undergo (3+2)-cycloadditions onto the enone fragment of the levoglucosenone molecule, yielding the corresponding, five-membered cycloadducts. In contrast to the 'classic' (Ph),(Ph) nitrile imine, reactions with fluorinated (CF),(Ar) analogues lead to stable pyrazolines in a chemo- and stereoselective manner. Based on the result of X-ray single crystal diffraction analysis, their structures were established as -cycloadducts with the location of the -Ar terminus of the 1,3-dipole at the α-position of the enone moiety.

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Micro/nanocapsules would have many more applications if we were able to controllably populate their surface with various chemical moieties. The present review introduces a novel variant of interfacial polymerization (IP) as a very robust method of manufacturing reservoir micro/nanocapsules equipped with several different functionalities on the capsules' surface. We call the method-IPCESCO (Interfacial Polymerization for Capsules' External Surface Control).

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(1-4)-Thiodisaccharides, thiosugars with the 1-4-thio bridge, were recently shown to induce oxidative stress, as well as, apoptosis in cancer cells in the low micromolar range; however, the detailed mechanism of their anticancer action still remains unknown. In order to clarify the mechanism of (1-4)- thiodisaccharides action, we performed a series of tests including cytotoxic, clonogenic and apoptosis assays using an in vitro glioma cancer model with one ATCC cell line U87 and two novel glioma cell lines derived from cancer patients - H6PX and H7PX. We also evaluated the ability of (1-4)-thiodisaccharides to interfere with protein folding and synthesis processes, as well as, the thioredoxin system.

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DNA double-strand breaks are considered one of the most lethal forms of DNA damage. Many effective anticancer therapeutic approaches used chemical and physical methods to generate DNA double-strand breaks in the cancer cells. They include: IR and drugs which mimetic its action, topoisomerase poisons, some alkylating agents or drugs which affected DNA replication process.

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Sugars with heteroatoms other than oxygen have attained considerable importance in glycobiology and in drug design since they are often more stable in blood plasma due to their resistance to enzymes, such as glycosidases, phosphorylases and glycosyltransferases. The replacement of oxygen atoms in sugars with sulfur forms thio-sugars, which are potentially useful for the treatment of diabetes and some bacterial and viral infections. Here, we evaluated the antibacterial activity of thio-functionalized carbohydrate derivatives.

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Thiosemicarbazides and their analogs have shown potential medical applications as antiviral, antibacterial and anticancer drugs. We designed, synthesized and evaluated in vitro anticancer activity against ovarian (A2780), cervix (HeLa), colon (LoVo), breast (MCF-7) and brain (MO59J) human cancer cell lines of seven novel compounds -S-glycosylated thiosemicarbazones. We assessed the cyto- and genotoxic properties of all novel compounds using a variety of methods including comet assay, XTT assay, various fluorescent assays and toxicology PathwayFinder expression array.

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(1-4)-S-thiodisaccharides were shown to kill various cancer cell lines, including cervix, lung, mammary-gland and colon by unknown mechanisms. Here we identified two actions of levoglucosenone derived (1-4)-S-thiodisaccharides against cervix cancer cells: induction of oxidative stress and DNA damage. In consequence, (1-4)-S-thiodisaccharides lowered the cellular GSH level and changed the expression profile of genes encoding key proteins involved with oxidative stress response.

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Thiosugars are carbohydrate analogs in which one or few of the oxygen atoms were replaced by sulfur. The sulfur atom which is present in the furan and pyran structures, changes biological properties of carbohydrates, as compared to their oxygen analogs. Among others, thiosugars are effective inhibitors of various cellular and enzymatic pathways and also have great therapeutic potential.

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Thio-sugars have been described as potent inhibitors of cancer cell growth but the detailed mechanism of action remains unknown. Herein we investigated the mechanism of their anticancer action in the HeLa cell line. We investigated two thio-sugars: 5-thio-d-glucose (FCP1) and 6-thio-β-d-fructopyranose (FCP2).

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1,5-Anhydro-6-deoxy-methane-sulfamido-D-glucitol (FCP5) is a functionalized carbohydrate containing functional groups that render it potentially therapeutically useful. According to our concept of 'functional carb-pharmacophores' (FCPs) incorporation of the methanesulfonamido pharmacophore to 1,5 glucitol could create a therapeutically useful compound. Our previous studies revealed that FCP5 was cytotoxic to cancer cells.

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Diverse functionalized representatives of (1-4)-S-thiodisaccharides, 6-9 were synthesized and assessed for cytotoxicity and apoptosis against human cancer cell lines (A549, LoVo, MCF-7 and HeLa). The FCP 6 was more active against MCF-7 cells (i.e.

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Diverse functionalized representatives of various classes of sugars, such as thio-, anhydro-, and sulfamido-sugars and myo-inositol oxide, were synthesized and assessed for cytotoxicity against human cancer cell lines (A549, LoVo, MCF-7 and HeLa). The inositol oxide (4) was more active against MCF-7 cells (i.e.

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The mycalamide class of potent antiviral and antitumor natural compounds originally isolated from marine sponges in 1988 is a new interdisciplinary approach to molecular recognition. We review new synthetic approaches to this new family of natural products with remarkable biological activity. Some biological evaluation data are compiled and compared to other structurally similar molecular targets.

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The base catalyzed conjugate Michael addition of the 1-thiosugar, 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranose, 1, to a new highly reactive enone 4-deoxy-1,2-O-isopropylidene-L-glycero-pent-4-enopyranos-3-ulose, 2, proceeds steroselectively with formation of adduct 3 in 94% yield. Convenient stereoselective reduction of the C-3 keto function of 3 with L-Selectride followed by in situ acetylation produces thiodisaccharide 4 in good 82% yield. Cleavage of the 1,2-O-isopropylidene protecting group with p-toluenesulfonic acid in methanol, followed by de-O-acetylation, produced an inseparable anomeric mixture of methyl 4-deoxy-5-C-(beta-D-glucopyranosyl)-thio-alpha/beta-L-ribo-pyranoside 5 in 72% overall yield.

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Thiosugars, containing a sulfur atom as heteroatom or a disaccharide linked via a sulfur bridge, possess unique physicochemical properties such as water solubility, which differs from conventional functionalized monosaccharides. The differences in biological activities between thiosugars and their oxygen analogs depend on geometric, conformational, and flexibility differences. They depend also on their electronic differences, the sulfide function being less electronegative and more polarizable than the ethereal moiety.

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Adhesive interactions between molecules expressed on vascular endothelium and circulating tumor cells are key early events in cancer metastasis. Best characterized to date is the selectin family of cell adhesion molecules, which can bind to and stabilize blood-borne cells on organ vasculature, facilitating the cell-cell and cell-substratum interactions leading to tumor seeding and proliferation. Major ligands of E-selectin, the selectin family member expressed on vascular endothelial cells, include sialylated, fucosylated glycans such as Sialyl Lewis type carbohydrate complexes (SLe(x) and SLe(a)).

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The first conversion of (1-->4)-thiodisaccharides into corresponding sulfoxides and sulfones by conventional oxidation with m-chloroperoxybenzoic acid (MCPBA) is reported. The effects of alpha-(1-->4)-3'-deoxythiodisaccharides (8-9) and their sulfoxide (14-15) and sulfone (16-17) derivatives on murine leukemia and human colon and pancreatic carcinoma cell viability were studied. Concentrations of thio-sugars that decreased tumor cell line viability by 50% (IC(50)), measured via the MTT assay, ranged from 6.

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