Joanna Wietrzyk

Synthesis, cytotoxicity and antibacterial activity of new esters of polyether antibiotic – salinomycin

A series of 12 novel ester derivatives of naturally occurring polyether antibiotic - salinomycin were synthesized, characterised by spectroscopic method and evaluated for their in vitro antibacterial activity and cytotoxicity. The new esters were demonstrated to form complexes with monovalent and divalent metal cation of 1:1 stoichiometry in contrast to the salinomycin which forms only complexes with monovalent cations. All the obtained compounds show potent antiproliferative activity against human cancer cell lines and a good selectivity index for cancer versus mammalian cells. Additionally, 3 compounds showed higher antiproliferative activity against the drug-resistant cancer cells and lower toxicity towards normal cells than those of unmodified salinomycin and standard anticancer drugs such as cisplatin and doxorubicin. Some of the synthesized compounds showed good inhibitory activity against Staphylococcus strains and clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE). These studies show that salinomycin esters are interesting scaffolds for the development of novel anticancer and Gram-positive antibacterial agents.

Rhodium(III) complexes with polypyridyls and pyrazole and their antitumor activity

Abstract Synthesis and properties of rhodium complexes with nitrogen ligands [RhCl 2 (Hpz) 4 ][RhCl 4 (Hpz) 2 ] ( 1 ), [RhCl 3 (tpy)] ( 2 ), [RhCl 3 (tpta)]·H 2 O ( 3 ) and [Rh(tpy) 2 (Him)]Cl 3 ·3H 2 O ( 4 ), have been described. X-ray structures of complexes 1 – 3 have been determined. IR, UV–Vis and 1 H NMR spectra of the complexes have been discussed. Cytostatic activity of the complexes against HCV29T tumor cells increases in the series: 1 3 2 4 . The cytostatic activity of complex 4 is greater than that of cisplatin. Interaction of the complexes with DNA has been investigated.

New insights into the possible role of bacteriophages in host defense and disease

BackgroundWhile the ability of bacteriophages to kill bacteria is well known and has been used in some centers to combat antibiotics – resistant infections, our knowledge about phage interactions with mammalian cells is very limited and phages have been believed to have no intrinsic tropism for those cells.Presentation of the hypothesisAt least some phages (e.g., T4 coliphage) express Lys-Arg-Gly (KGD) sequence which binds β3 integrins (primarily αIIbβ3). Therefore, phages could bind β3+ cells (platelets, monocytes, some lymphocytes and some neoplastic cells) and downregulate activities of those cells by inhibiting integrin functions.Testing the hypothesisBinding of KGD+ phages to β3 integrin+ cells may be detected using standard techniques involving phage – mediated bacterial lysis and plaque formation. Furthermore, the binding may be visualized by electron microscopy and fluorescence using labelled phages. Binding specificity can be confirmed with the aid of specific blocking peptides and monoclonal antibodies. In vivo effects of phage – cell interactions may be assessed by examining the possible biological effects of β3 blockade (e.g., anti-metastatic activity).Implication of the hypothesisIf, indeed, phages can modify functions of β3+ cells (platelets, monocytes, lymphocytes, cancer cells) they could be important biological response modifiers regulating migration and activities of those cells. Such novel understanding of their role could open novel perspectives in their potential use in treatment of cardiovascular and autoimmune disease, graft rejection and cancer.

Antiproliferative activity of salinomycin and its derivatives.

Antiproliferative activity of seven amides and one benzotriazole ester derivative of salinomycin, a polyether ionophore antibiotic, with recently reported antibacterial activity, are herein described. Salinomycin and the majority of derivatives exhibit potent antiproliferative activity against the drug-resistant cancer cell lines. Moreover almost all derivatives show stronger activity against LoVo/DX cell line than that of unmodified salinomycin.

Anticancer activity of the Uncaria tomentosa (Willd.) DC. preparations with different oxindole alkaloid composition.

The activity of Uncaria tomentosa preparations on cancer cells was studied using in vitro and in vivo models. IC (50) values were calculated for preparations with different quantitative and qualitative oxindole alkaloid composition: B/W(37) --bark extracted in water at 37 °C, B/W(b)--bark extracted in boiling water, B/50E(37) --bark extracted in 50% ethanol at 37 °C, B/E(b)--bark extracted in boiling 96% ethanol, B/96E(37) --bark extracted in 96% ethanol at 37 °C and B/SRT--bark extracted in water and dichloromethane. Generally, the results obtained showed a high correlation between the total oxindole alkaloid content (from 0.43% to 50.40% d.m.) and the antiproliferative activity of the preparations (IC(50) from >1000 μg/ml to 23.57 μg/ml). B/96E(37) and B/SRT were the most cytotoxic preparations, whereas the lowest toxicity was observed for B/W(37). B/96E(37) were shown to be active against Lewis lung carcinoma (LL/2) [IC(50) =25.06 μg/ml], cervical carcinoma (KB) [IC(50) =35.69 μg/ml] and colon adenocarcinoma (SW707) [IC(50) =49.06 μg/ml]. B/SRT was especially effective in inhibiting proliferation of cervical carcinoma (KB) [IC(50) =23.57 μg/ml], breast carcinoma (MCF-7) [IC(50) =29.86 μg/ml] and lung carcinoma (A-549) [IC(50) =40.03 μg/ml]. Further animal studies on mice bearing Lewis lung carcinoma showed significant inhibition of tumor growth by B/W(37) administered for 21 days at daily doses of 5 and 0.5 mg (p=0.0009). There were no significant changes in the cell cycles of tumor cells with the exception of cell decrease at the G₂/M phase after the administration of B/96E(37) at a daily dose of 0.5 mg and the G(1)/G(0) cells cycle arrest demonstrated after the B/SRT therapy at a daily-dose of 0.05 mg. All tested preparations were non-toxic and well tolerated.

Synthesis and in vitro antiproliferative activity of new 11-aminoalkylamino-substituted 5H- and 6H-indolo(2,3-b)quinolines; structure-activity relationships of neocryptolepines and 6-methyl congeners

The present report describes the synthesis and antiproliferative evaluation of certain 11-aminoalkylamino-substituted 5H- and 6H-indolo[2,3-b]quinolines and their methylated derivatives. These 5-Me- and 6-Me-indolo[2,3-b]quinoline derivatives 10-14, 20 were prepared by amination at the C-11 position of the 11-chloro-5-methyl-5H- and 11-chloro-6-methyl-6H-indolo[2,3-b]quinolines with different substituents on the quinoline ring. The 11-aminoalkylaminomethylated 23, the homologue of 11, was prepared from the same intermediate for a further SAR study. These intermediates are accessible from 4-substituted anilines or their N-methylated analogues and methyl indole-3-carboxylate as a counterpart. The in vitro antiproliferative assay indicated that the 5-methylated derivatives 10-14 are more cytotoxic than their respective 6-methylated 6H-indolo[2,3-b]quinoline derivatives 20. Among them, N-(3-aminopropyl)-2-bromo-5-methyl-5H-indolo[2,3-b]quinolin-11-amine 12f was the most cytotoxic with a mean IC(50) value of 0.12 μM against human leukemia MV4-11 cell line, and also exhibited selective cytotoxicities against A549 (lung cancer), HCT116 (colon cancer) cell lines and normal fibroblast BALB/3T3 with IC(50) values of 0.543, 0.274 and 0.869 μM, respectively. The binding constant of products 12f and 20f to salmon fish sperm DNA were also evaluated using UV-vis absorption spectroscopy, indicating intercalation binding with a constant of 2.93×10(5) and 3.28×10(5)Lmol(-1), respectively.

Silver(I) complexes with hydantoins and allantoin☆ Synthesis, crystal and molecular structure, cytotoxicity and pharmacokinetics

Coordination polymers [Ag(L(1,3))](n) (L(1)=hydantoin, L(3)=5,5-dimethylhydantoin), {[Ag(L(2))](.)0.5H(2)O}(n) (L(2)=1-methylhydantoin) and [Ag(NH(3))(L(4))](n) (L(4)=allantoin) were prepared and characterized by elemental analysis, spectroscopic (IR, FTIR and NMR), thermal and mass spectrometry methods. The crystal structure of {[Ag(1-methylhydantoin)]·0,5H(2)O}(n) was determined and analyzed. Three 1-methylhydantoinate ligands create a T-shape (CN=3) coordination sphere around the Ag(+) ion. Additionally, a short Ag⋯Ag distance of 2.997Å was found in the structure resulting in the expanded [3+2] environment of a distorted square shape. The [Ag(L(2))] entities are bound to each other by the bridging organic ligands. Thus a two-dimensional coordination polymer is created with water molecules located between the layers. In contrast to hydantoins, the allantoin complex contains an additional ammonia molecule in the coordination sphere. Moreover, in the Ag-alla complex the M-organic ligand binding site is shifted to the N-atom of the ureid chain. Free ligands are cytotoxically inactive against human MCF-7 and A549 cancer cell lines and mouse fibroblasts Balb/3T3. The silver hydantoin complexes exhibit a very strong activity against these lines. (The introduction of the methyl groups to the ring slightly increases resistance only against the A549 cell line.) In contrast, the silver complex of allantoin shows only a weak activity which may be related to the presence of the cytotoxic ammonia group in the composition of the compound and/or the different binding site of the ligand. Calculated in silico physiochemical parameters are promising for the future application of the complexes as drugs.

Synthesis, antiproliferative and antibacterial activity of new amides of salinomycin.

A series of 11 novel amides of salinomycin were synthesized for the first time. All the obtained compounds were found to show potent antiproliferative activity against human cancer cell lines including the drug-resistant cancer cells. Four new salinomycin derivatives revealed good antibacterial activity against clinical isolates of methicillin-resistant Staphylococcus epidermidis (MRSE).

Synthetic conjugates of genistein affecting proliferation and mitosis of cancer cells

This paper describes the synthesis and antiproliferative activity of conjugates of genistein (1) and unsaturated pyranosides. Constructs linking genistein with a sugar moiety through an alkyl chain were obtained in a two-step synthesis: in a first step genistein was converted into an intermediate bearing an ω-hydroxyalkyl substituent, containing two, three or five carbon atoms, at position 7, while the second step involved Ferrier glycosylation reaction, employing glycals. Antiproliferative activity of several genistein derivatives was tested in cancer cell lines in vitro. The most potent derivative, Ram-3 inhibited the cell cycle, interacted with mitotic spindles and caused apoptotic cell death. Neither genistein nor the sugar alone were able to influence the mitotic spindle organization. Our results indicate, that conjugation of genistein with certain sugars may render the interaction of derivatives with new molecular targets.

Biological activity in vitro of side-chain modified analogues of calcitriol.

The results of our studies on the biological activity of side-chain modified analogues of vitamin D are reviewed. These analogues appeared to be effective in induction of cell differentiation, inhibition of tumour cell proliferation in vitro and in increasing of antitumour effect of cytostatics. On the other hand, inhibition of cytostatic-induced apoptosis by these compounds was observed. The mechanism of the antiproliferative effect of calcitriol analogues in vitro is discussed. The induction of antigens CD14 and CD11b expression and phagocytic activity of HL-60 cells after exposure to these compounds is related to their effect on cell differentiation. The differentiation of the HL-60 leukaemia cells induced by side-chain modified analogues of calcitriol increases their sensitivity to the antiproliferative effect of cisplatin, doxorubicin and genistein, despite of that this pretreatment causes resistance of these cells to cytostatics-induced apoptosis. We observed a synergistic antiproliferative effect of the combined therapy using analogues of calcitriol with subsequent treatment with the above-mentioned cytostatics. This effect was measured as a significant decrease of the ID50 values for each cytostatic applied after pretreatment of the tumour cells with the calcitriol analogues. The results presented suggest that the improved therapeutic effect may be achieved also in vivo by the combined application of the analogues (without calcemic activity) of calcitriol with antitumour agents.