Synthesis, characterization, HSA/DNA interactions and antitumor activity of new [Ru(η6-p-cymene)Cl2(L)] complexes

Three new ruthenium(II) complexes were synthesized from different substituted isothiazole ligands 5-(methylamino)-3-pyrrolidine-1-ylisothiazole-4-carbonitrile (1), 5-(methylamino)-3- (4-methylpiperazine-1-yl)isothiazole-4-carbonitrile (2) and 5-(methylamino)-3-morpholine-4- ylisothiazole-4-carbonitrile (3): [Ru(η6-p-cymene)Cl2(L1)]·H2O (4), [Ru(η6 -pcymene)Cl2(L2)] (5) and [Ru(η6-p-cymene)Cl2(L3)] (6). All complexes were characterized by IR, UV-Vis, NMR spectroscopy, and elemental analysis. The molecular structures of all ligands and complexes 4 and 6 were determined by an X-ray. The results of the interactions of CT-DNA (calf thymus deoxyribonucleic acid) and HSA (human serum albumin) with ruthenium (II) complexes reveal that complex 4 binds well to CT-DNA and HSA. Kinetic and thermodynamic parameters for the reaction between complex and HSA confirmed the associative mode of interaction. The results of Quantum mechanics (QM) modelling and docking experiments toward DNA dodecamer and HSA support the strongest binding of the complex 4 to DNA major groove, as well as its binding to IIa domain of HSA with the lowest ΔG energy, which agrees with the solution studies. The modified GOLD docking results are indicative for Ru(p-cymene)LCl··(HSA··GLU292) binding and GOLD/MOPAC(QM) docking/modelling of DNA/Ligand (Ru(II)-N(7)dG7) covalent binding. The cytotoxic activity of compounds was evaluated by MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl2H-tetrazolium bromide) assay. Neither of the tested compounds shows activity against a healthy MRC-5 cell line while the MCF-7 cell line is the most sensitive to all. Compounds 3, 4 and 5 were about two times more active than cisplatin, while the antiproliferative activity of 6 was almost the same as with cisplatin. Flow cytometry analysis showed the apoptotic death of the cells with a cell cycle arrest in the subG1 phase

Synthesis and antiproliferative activity of some A- and B modified D-homo lactone androstane derivatives

An efficient synthesis of several A- and B-modified D-homo lactone androstane derivatives from 3β-hydroxy-17-oxa-D-homoandrost-5-en-16-one (1) is reported. 17-Oxa-Dhomoandrost- 4-ene-3,16-dione (2), obtained by the Oppenauer oxidation of compound 1, was converted via the unstable intermediate 3,16-dioxo-4,17-dioxa-D-homoandrostane- 5α-carboxaldehyde (3) to 17-oxa-D-homo-3,5-seco-4-norandrostan-5-one-3-carboxylic acid (4), which was also obtained directly from compound 2. Compound 1 was acetylated to give 17-oxa-D-homoandrost-5-en-16-on-3β-yl acetate (5) which was then oxidized with chromium(VI)-oxide in 50% acetic acid or with meta-chlorperbenzoic acid and chromium(VI)-oxide to yield compounds 6-8 and 5α-hydroxy-17-oxa-D-homoandrostane- 6,16-dion-3β-yl acetate (9), respectively. The oximination of compound 9 gave a mixture of 6(E)-hydroximino-5α-hydroxy-17-oxa-D-homoandrostan-16-on-3β-yl acetate (10) and 6(Z)-hydroximino-5α-hydroxy-17-oxa-D-homoandrostan-16-on-3β-yl acetate (11), the hydrolysis of which gave 6(E)-hydroximino-3β,5α-dihydroxy-17-oxa-D-homoandrostan- 16-one (12) and 6(Z)-hydroximino-3β,5α-dihydroxy-17-oxa-D-homoandrostan-16-one (13). 6-Nitrile-17-oxa-5,6-seco-D-homoandrostane-5,16-dion-3β-yl acetate (14) was obtained under the Beckmann fragmentation of compounds 10 and 11. Only pure and stable compounds (1, 2, 4, 5, 9 and 14) were tested in vitro on six malignant cell lines (MCF-7, MDA-MB-231, PC-3, HeLa, HT-29, K562) and one non-tumor MRC-5 cell line. Significant antiproliferative activity against MDA-MB-231 cells showed compounds 1, 5 and 9, while compound 2 exhibited a strong antiproliferative activity. Only compound 14 showed weak antiproliferative activity against MCF-7 cells. All tested compounds were not toxic on MRC-5 cells, whereas Doxorubicin was highly toxic on these cells. [Projekat Ministarstva nauke Republike Srbije, br. 172021

Synthesis and antiproliferative activity of (5R)-cleistenolide and analogues

(5R)-Cleistenolide and a few related analogues have been synthesized starting from d-glucose. The key steps of the synthesis included a Z-selective Wittig olefination and an intramolecular Mitsunobu reaction with an inversion of configuration at the C-5 position. In vitro antiproliferative activity of synthesized compounds was tested on a panel of eight human tumour cells and against a single normal cell line (MRC-5). The majority of tested compounds showed strong antiproliferative effects on certain human tumour cells and all of them showed negligible toxicity to normal foetal lung fibroblasts (MRC-5). The most active compound obtained in this work is lactone 5, which in MDA-MB 231 cell culture showed the same activity as doxorubicin (IC50 0.09 μM). Strong antiproliferative activities of analogues 2, 5 and 6 were recorded in the K562 cell line (IC50 0.21, 0.34 and 0.33 μM, respectively), in which they showed very similar activities to doxorubicin (IC50 0.25 μM). A performed SAR study revealed that a change in the stereochemistry at the C-5 position may increase the activity of resulting stereoisomers

1,2,3,4-Tetrahydroisoquinoline Derivatives as a Novel Deoxyribonuclease I Inhibitors

Herein we report an assessment of 24 1,2,3,4-tetrahydroisoquinoline derivatives for potential DNase I (deoxyribonuclease I) inhibitory properties in vitro. Four of them inhibited DNase I with IC50 values below 200 μM. The most potent was 1-(6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolin-1-yl)propan-2-one (2) (IC50=134.35±11.38 μM) exhibiting slightly better IC50 value compared to three other active compounds, 2-[2-(4-fluorophenyl)-1,2,3,4-tetrahydroisoquinolin-1-yl]-1-phenylethan-1-one (15) (IC50=147.51±14.87 μM), 2-[2-(4-fluorophenyl)-1,2,3,4-tetrahydroisoquinolin-1-yl]cyclohexan-1-one (18) (IC50=149.07±2.98 μM) and 2-[6,7-dimethoxy-2-(p-tolyl)-1,2,3,4-tetrahydroisoquinolin-1-yl]cyclohexan-1-one (22) (IC50=148.31±2.96 μM). Cytotoxicity assessment of the active DNase I inhibitors revealed a lack of toxic effects on the healthy cell lines MRC-5. Molecular docking and molecular dynamics simulations suggest that interactions with Glu 39, His 134, Asn 170, Tyr 211, Asp 251 and His 252 are an important factor for inhibitors affinity toward the DNase I. Observed interactions would be beneficial for the discovery of new active 1,2,3,4-tetrahydroisoquinoline-based inhibitors of DNase I, but might also encourage researchers to further explore and utilize potential therapeutic application of DNase I inhibitors, based on a versatile role of DNase I during apoptotic cell death

Synthesis, in vitro and in silico anticancer evaluation of novel pyridin-2-yl estra-1,3,5(10)-triene derivatives

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