Sabina Tabaczar

Publications of Sabina Tabaczar

• [Nitroxides as antioxidants - possibilities of their application in chemoprevention and radioprotection].

  Authors: Sabina Tabaczar, Marcin Talar, Krzysztof Gwoździński

  Postȩpy higieny i medycyny doświadczalnej (Online). 01/2011; 65:46-54.

  Nitroxides as stabile organic radicals were used initially as spin labels in spectroscopy of electron paramagnetic resonance (EPR) with respect to parameters such as pH of an intercellularNitroxides as stabile organic radicals were used initially as spin labels in spectroscopy of electron paramagnetic resonance (EPR) with respect to parameters such as pH of an intercellular environment, oxygenation of cells and tissues, fluidity of biological membranes, conformational state and topography of proteins. Nitroxides have also been used in biology and medicine as contrast agents in magnetic resonance imaging (MRI). When their antioxidant activities were discovered, an era of research on the potential utility of these agents began. Nitroxides can modulate the redox state of the cell by participation in oxidation/reduction reactions. Therefore, they are extensively examined in various models of oxidative stress. The antioxidant effect of nitroxides is a result of their ability to catalyze dismutation of superoxide radical (superoxide dismutase-like activity), inhibit lipid peroxidation, prevent Fenton and Haber-Weiss reactions by oxidation of transition metal ions to a higher oxidative state, and confer catalase-like activity on heme proteins. In the present paper the antioxidative mechanisms of nitroxides are presented. The relation between structure, function and the rate of nitroxide reduction inside cells and tissues is also presented. The application of nitroxides in chemoprevention and radioprotection is discussed.

• [Molecular mechanisms of antitumor activity of taxanes. I. Interaction of docetaxel with microtubules].

  Authors: Sabina Tabaczar, Aneta Koceva-Chyła, Karolina Matczak, Krzysztof Gwoździński

  Postȩpy higieny i medycyny doświadczalnej (Online). 01/2010; 64:568-81.

  Docetaxel (Taxotere), a new semisynthetic taxoid, is a mitotic inhibitor, widely used in monotherapy or in combination with other anticancer drugs against many types of cancer. The structure andDocetaxel (Taxotere), a new semisynthetic taxoid, is a mitotic inhibitor, widely used in monotherapy or in combination with other anticancer drugs against many types of cancer. The structure and dynamics of microtubules as the main target for docetaxel activity inside the cell and the taxane-binding site on β-tubulin are discussed. Microtubules are highly dynamic assemblies of α- and β-tubulin. They readily polymerize and depolymerize in cells and these dynamic behaviours are crucial to cell mitosis. Microtubule instability is attributed to their capability to hydrolyze GTP to GDP, which causes their depolymerization. Addition of new α-, β-tubulin heterodimer bound to GTP leads to tubulin polymerization, which increases the length of the microtubule. Docetaxel alters the polymerization dynamics of microtubules, which causes blockage of cell mitosis, and consequently induces apoptotic and non-apoptotic cell death. Docetaxel specifically acts on the S, M and G2 phases of the cell cycle. This paper reviews the current state of knowledge related to the molecular mechanisms of docetaxel action on the cell cycle and microtubule dynamics. In addition, a brief survey of the present state of research on the new generation (2nd and 3rd) of taxanes is presented.