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Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in men and in women. The impact of the new pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulphonamide (MM-129) was evaluated against human colon cancer in vitro and in zebrafish xenografts. Our results show that this new synthesised compound effectively inhibits cell survival in BTK-dependent mechanism. Its effectiveness is much higher at a relatively low concentration as compared with the standard chemotherapy used for CRC, i.e. 5-fluorouracil (5-FU). Flow cytometry analysis after annexin V-FITC and propidium iodide staining revealed that apoptosis was the main response of CRC cells to MM-129 treatment. We also found that MM-129 effectively inhibits tumour development in zebrafish embryo xenograft model, where it showed a markedly synergistic anticancer effect when used in combination with 5-FU. The above results suggest that this novel heterofused 1,2,4-triazine derivative may be a promising candidate for further evaluation as chemotherapeutic agent against CRC. [ABSTRACT FROM AUTHOR]

The significant role of topoisomerases in the control of DNA chain topology has been confirmed in numerous research conducted worldwide. The prevalence of these enzymes, as well as the key importance of topoisomerase in the proper functioning of cells, have made them the target of many scientific studies conducted all over the world. This article is a comprehensive review of knowledge about topoisomerases and their inhibitors collected over the years. Studies on the structure–activity relationship and molecular docking are one of the key elements driving drug development. In addition to information on molecular targets, this article contains details on the structure–activity relationship of described classes of compounds. Moreover, the work also includes details about the structure of the compounds that drive the mode of action of topoisomerase inhibitors. Finally, selected topoisomerases inhibitors at the stage of clinical trials and their potential application in the chemotherapy of various cancers are described. [ABSTRACT FROM AUTHOR]

Six novel compounds of platinum(II) with pyrazole derivatives PtPz1-PtPz6 were synthesised and characterised (PtPz1 - [Pt2N-hydroksymethyl-3,5-dimethylpyrazole4(berenil)2]Cl4; PtPz2 - [Pt23,5-dimethylpyrazole4(berenil)2]Cl4; PtPz3 - [Pt23,4-dimethylpyrazole4(berenil)2]Cl4; PtPz4 - [Pt2pyrazole4(berenil)2]Cl4; PtPz5- [Pt25-methylpyrazole4(berenil)2]Cl4; PtPz6 - [Pt2N-ethylpyrazole4(berenil)2]Cl4). The cytotoxic activity of these complexes against MCF-7 and MDA-MB-231 breast cancer cell lines was determined using the MTT assay. Evaluation of apoptosis induction was done with the Annexin V-fluorescein isothiocyanate/propidium iodide assay. In addition, using a flow cytometer, we determined the influence of test compounds on the cell cycle and caspase-3, -8, and -9 activity. The obtained results of caspase activity were confirmed by cell imaging. Moreover, using the flow cytometer, the effects of the test compounds on mitochondrial potential change were assessed. The test results showed that novel pyrazole-platinum(II) complexes exhibited stronger anti-proliferative activity against two breast cancer cell lines than reference cisplatin. Compounds PtPz1, PtPz2, and PtPz3 with methyl substituents at the pyrazole ring showed stronger activity than pyrazole or ethylpyrazole containing complexes. Studies have shown that inhibition of cell survival occurs by arresting the G1 cell cycle and inducing apoptosis. Our analysis associated with the response of MCF-7 and MDA-MB-231 cells to treatment with PtPz1-PtPz6 showed that it leads the cells through the external and intrinsic (mitochondrial) apoptotic pathway via indirect DNA damage. [ABSTRACT FROM AUTHOR]

This study investigates the effect of three new platinum complexes: Pt2(2,4-dimethylpyridine) 4(berenil)2 (Pt14), Pt2(3,4-dimethylpyridine)4(berenil)2 (Pt15) and Pt2(3,5-dimethylpyridine) 4(berenil)2 (Pt16) on growth and viability of breast cancer cells and their putative mechanism(s) of cytotoxicity. Cytotoxicity was measured with MTT assay and inhibition of [3H]thymidine incorporation into DNA in both breast cancer cells. Results revealed that Pt14-Pt16 exhibit substantially greater cytotoxicity than cisplatin against MCF-7 and MDAMB- 231 breast cancer cells. In the case of human skin fibroblast cell, cytotoxicity assays demonstrated that these compounds are less toxic to normal cells than cisplatin. In addition, the effects of Pt14-Pt16 are investigated using the flow cytometry assessment of annexin V binding, analysis of mitochondrial potential, markers of apoptosis such as caspase-3, caspase-8, caspase-9, caspase-10 and defragmentation of DNA by TUNEL assay. These results indicate that Pt14-Pt16 induce apoptosis by the mitochondrial and external pathway. [ABSTRACT FROM AUTHOR]

A series of six 2,5-disubstituted 1,3,4-thiadiazole derivatives was synthesized and examined for cytotoxic activity in MCF-7 and MDA-MB-231 breast cancer cells. MTT assay confirmed that 2-(3-fluorophenylamino)-5-(3-hydroxyphenyl)-1,3,4-thiadiazole (2), 2-(4-bromophenylamino)-5-(2,4-dichlorophenyl)-1,3,4-thiadiazole (3), 2-(4-fluorophenylamino)-5-(2,4-dichlorophenyl)-1,3,4-thiadiazole (4), had ability to inhibit MCF-7 and MDA-MB-231 cells proliferation. The IC50values for the mentioned compounds ranged between 120 and 160 μM (with respect to MCF-7 cells) and from 70 to 170 μM (with respect to MDA-MB-231 cells). It turned out, moreover, that compound2is a human topoisomerase II (topoII) catalytic inhibitor whereas the two other compounds (i.e.3and4) are capable of stabilizing DNA-topoII cleavage complex and thus are topoII poisons. [ABSTRACT FROM AUTHOR]

A series of eight thiosemicarbazide derivatives was examined for cytotoxicity in breast cancer cell cultures. Among them, 4-benzoylthiosemicarbazides proved to be only slightly less potent than chlorambucil in both MDA-MB-231 and MCF-7 lines. In contrast, 4-aryl/alkylthiosemicarbazides revealed significantly lower cytotoxicity effect. Subsequently, all titled compounds were tested as potential human topoisomerase I and II (topo I and topo II) inhibitors. Mechanistic studies revealed that tested thiosemicarbazides act as both topoisomerase I and topoisomerase II inhibitors. Among them, the best inhibitory activity was found for 4-benzoylthiosemicarbazides ( 1 and 2) with IC50 at 50 µM against topo II. [ABSTRACT FROM AUTHOR]