Antitumor activity of Ru(III) complexes carrying beta-diketonato ligands in vitro and in vivo.

PURPOSE: To investigate the antitumor activity of two newly synthesized ruthenium(III) [Ru(III)] compounds carrying bidentate ligands: (acac)-acetylacetonate, [Ru(acac)3), and (tfac)-trifluoroacetylacetonate [Ru(tfac)3]. MATERIALS AND METHODS: The activity of ruthenium(III) analogues was evaluated on HeLa, B16, and Femx cell lines for cytotoxicity in vitro using MTT assay, and inhibition on tumor invading ability in vitro using cell migration and invasion assays, whereas inhibition of tumor growth in vivo was estimated on advanced B16 murine melanoma model. Both compounds were also investigated in combinations with cisplatin, oxaliplatin, or poly ADP-ribose polymerase- 1 (PARP-1) inhibitor, in order to determine the pattern of mutual interactions. RESULTS: Applied as single drugs, Ru(tfac)3 showed high cytotoxic activity against HeLa and Femx cell lines, while Ru(acac)3 did not reach the IC50 on any of the cell lines tested. In combinations, Ru(acac)3 with cisplatin gained synergistic interaction, antagonistic with oxaliplatin, and of different kind with (PARP-1) inhibitor in concentration-and cell line-dependent manner. Ru(acac)3 exhibited inhibition of HeLa cell migration and gelatinolytic activity of MMP-2 and MMP-9. Ru(tfac)3 complexes did not induce significant reduction of melanoma growth in vivo, whereas Ru(acac)3 did, but the latter failed to contribute in lifespan improvement. CONCLUSION: The investigated ruthenium complexes showed different levels of antitumor activity in vitro and in vivo, implicating on different mechanisms of their action as well as diverse perspectives in cancer treatment.

Cellular sensitivity to beta-diketonato complexes of ruthenium(III), chromium(III) and rhodium(III).

The aim of this study was to investigate cellular response to several ruthenium(III), chromium(III) and rhodium(III) compounds carrying bidentate beta-diketonato ligands: [(acac)--acetylacetonate ligand, (tfac)--trifluoroacetylacetonate ligand]. Cell sensitivity studies were performed on several cell lines (A2780, cisplatin-sensitive and -resistant U2-OS and U2-OS/Pt, HeLa, B16) using growth-inhibition assay. Effect of intracellular GSH depletion on cell sensitivity to the agents was analyzed in A2780 cells. Flow cytometry was used to assess apoptosis by Annexin-V-FITC/PI staining, and to analyze induction of caspase-3 activity. Possible DNA binding/damaging affinity was investigated, by inductively coupled mass spectrometry, and by 14C-thymidine / 3H-uridine incorporation assay. Cell sensitivity studies showed that the pattern of sensitivity to Ru(tfac)3 complex of the two cisplatin-sensitive/-resistant osteosarcoma cell lines, U2-OS and U2-OS/Pt, was similar to that of A2780 cells (72 h exposure), with the IC50 being around 40 microM. The growth-inhibitory effect of Ru(acac)3 ranged over 100 microM, while Cr(III) and Rh(III) complexes were completely devoid of antitumor action in vitro. Ru(tfac)3 exhibited strong potential for apoptosis induction on A2780 cells (up to 40%) and caused cell cycle arrest in the S phase as well as decrease of the percent of G1 and G2 cells. Ru(acac)3-induced apoptosis was slightly higher than 10%, whereas activation of caspase-3 in HeLa cells was moderate. DNA binding study revealed that only Cr(acac)3 was capable of binding DNA, while Cr(III) and Ru(III) compounds possess potential to inhibit DNA/RNA synthesis. In conclusion, only Ru(III) complexes showed potential for antitumor action.

Antiproliferative activity of some cis-/trans-platinum(II) complexes on HeLa cells.

Purpose of this work was to synthesize several cis-/trans- isomer pairs of the platinum(II) complexes, and study the extent and the mode of their antiproliferative activity on HeLa cells. Six platinum(II) isomer pairs have a general formula cis-/trans-[PtA2X2], where A is ligand: ammonia (NH3), pyridine (Py); and X is ligand: chloride ion (Cl-), bromide ion (Br-), iodide ion (I-), thiocyanato ion (SCN-); four compounds have different structural formulas, and these are cis-/trans-[Pt(NH2OH)2(NH3)2]Cl2, and cis-/trans-Pt(Gly)2, where Gly is bidentate glycinato ligand. Results of the MTT assay, showed that six cis- and one trans-platinum(II) complexes exhibited cytotoxicity (IC50) ranging between 5 and 33 microM. Most of the cis-platinum(II) isomers caused significant alteration of cell cycle phases progression, and induced apoptosis in degree that varied among different compounds, as evaluated using flowcytometry and morphological study. Spectrophotometric analysis (AAS) indicated that there is no correlation between intracellular platinum(II) accumulation and cytotoxicity of tested complexes.

[The role of prostaglandins in allergic inflammation]. / Uloga prostaglandina u alergijskoj inflamaciji.

Prostaglandins likewise leukotriens are proinflammatory mediators resulting from metabolic degradation of the arachidonic acid originating from membrane phospholipids. The most important products of enzyme cyclooxygenation of arachidonic acid are prostaglandins D2, E2, F2a, tromboxane A2 and prostacyclin. Prostaglandins express their tissue effects via the five basic receptor types. Within the allergic inflammation activated mast cell synthesizes prostaglandin D2 (first lipid mediator) which has bronchoconstrictive and vasodilating effects and attracts neutrophilic leukocytes. Moreover, it also participates in the late phase reactions, six hours subsequent to the exposure to the allergen. This mediator is also important in pathogenesis of urticaria, allergic rhinitis and allergic bronchial asthma. In addition to prostaglandin D2, prostaglandin F2a and tromboxane A2 also have bronchoconstrictive actions, while prostacyclin and prostaglandin E have bronchodilating effects. Inhalation of prostaglandin E prevents asthmatic attacks caused by allergens, strain, metabisulfite and ameliorates attacks of aspirin asthma, which confirms the hypothesis that aspirin asthma is based on cyclooxigenase inhibition and increased leukotriene production. In patients with atopic dermatitis, prostaglandin E has suppressive effects on Interferon gamma production by Th1 helper cells and increases production of Interleukin 4 by the Th2 cells. Tromboxane A2 plays a certain role in the development of bronchial hyperreactivity and late asthmatic response. Prostaglandins are also important mediators in the pathogenesis of allergic conjunctivitis. Most of nonsteroidal antiinflammatory drugs inhibit the enzyme cyclooxygenase and thus also prostaglandin biosynthesis and release.

[The role of mononuclear phagocytes and dendritic cells in allergic inflammation]. / Uloga mononuklearnih fagocita i dendriticnih celija u alergijskoj inflamaciji.

Mononuclear-phagocytic system is a diffuse network of cells which includes monoblasts and promonocytes of the bone marrow, blood monocytes, as well as free and fixed tissue macrophage cells. In different tissues and organs macrophages acquire different morphological and functional properties under the influence of the local tissue factors. Interaction of macrophages with other cells and molecules is performed via the large number of different receptors resulting in activation of the macrophage cell, accompanied by a series of morphological and metabolic changes which potentiate all its functions. Activated macrophage cells were found in certain diseases. Macrophages and dendritic cells are associated with all aspects of immunity. Owing to their capacity to undergo phagocytosis they are of the utmost importance for unspecific defense from microorganisms. As accessory cells they also participate in cellular and humoral immunity, being at the same time effector cells owing to their capacity of antigen presentation. Moreover, they also participate in immune response regulation owing to their influence on the function of other cells, including mast cells, basophilic leukocytes and T lymphocytes, in which they may influence differentiation toward Th1 or Th2 and cytokine milieu favorable for allergic reaction. Dendritic cells are the most important antigen-presenting cells and thus, they play a major role in activation of helper T lymphocytes, and mode of antigen presentation is significant for regulation of the nature and intensity of the immune response. Pulmonary macrophage cells have been most thoroughly studied, and the observed changeability of their functional and morphological characteristics is of the utmost importance for studying of the pathogenetic properties and regulation of the chronic inflammatory response in bronchial asthma.