Kamil Motyka

7-(2-Thienyl)-7-Deazaadenosine (AB61), a New Potent Nucleoside Cytostatic with a Complex Mode of Action

7-(2-Thienyl)-7-deazaadenosine (AB61) showed nanomolar cytotoxic activities against various cancer cell lines but only mild (micromolar) activities against normal fibroblasts. The selectivity of AB61 was found to be due to inefficient phosphorylation of AB61 in normal fibroblasts. The phosphorylation of AB61 in the leukemic CCRF-CEM cell line proceeds well and it was shown that AB61 is incorporated into both DNA and RNA, preferentially as a ribonucleotide. It was further confirmed that a triphosphate of AB61 is a substrate for both RNA and DNA polymerases in enzymatic assays. Gene expression analysis suggests that AB61 affects DNA damage pathways and protein translation/folding machinery. Indeed, formation of large 53BP1 foci was observed in nuclei of AB61-treated U2OS-GFP-53BP1 cells indicating DNA damage. Random incorporation of AB61 into RNA blocked its translation in an in vitro assay and reduction of reporter protein expression was also observed in mice after 4-hour treatment with AB61. AB61 also significantly reduced tumor volume in mice bearing SK-OV-3, BT-549, and HT-29 xenografts. The results indicate that AB61 is a promising compound with unique mechanism of action and deserves further development as an anticancer agent. Mol Cancer Ther; 15(5); 922–37. ©2016 AACR.

Synthesis and study of novel pH-independent fluorescent mitochondrial labels based on Rhodamine B

Several Rhodamine B derivatives based on a tri-substituted pyrimidine core were prepared using solid-phase chemistry with a combinatorial approach. These compounds were screened for their basic fluorescence properties and their ability to penetrate through eukaryotic cell membranes. Most can penetrate through the cell membrane and specifically accumulate in mitochondria. Notably, some of our new rhodamine derivatives showed partially sustained mitochondrial localization and exhibited fluorescence at high pH, making them promising candidates for molecular probes to elucidate mitochondrial biology and pathology.

Preparation of 2-phenyl-3-hydroxyquinoline-4(1H)-one-5-carboxamides as potential anticancer and fluorescence agents

The synthesis of 3-hydroxyquinoline-4(1H)-one derivatives bearing substituted phenyl in position 2 and variously substituted carboxamide group in position 5 is described, with use of 3-nitrophthalic anhydride, α-haloketones and primary amines as the starting materials. The synthetic approach was inspired by the preparation of analogous derivatives reported previously. However, a different strategy had to be developed with the corresponding bis(phenacyl)-3-aminophthalates as the key intermediates. Synthesized hydroxyquinolinones, as well as their intermediates, were tested for their cytotoxic activity towards various cancer and non-malignant cell lines. The fluorescent properties of these compounds have also been evaluated. In both fields, interesting data were obtained and compared to isomeric compounds that have been studied in the past.

RP-HPLC determination of dissociation constant using solely aqueous mobile phase

HIGHLIGHTSThe proposed HPLC method uses solely or nearly 100% aqueous mobile buffer as mobile phase.The method offers fast determination of dissociation constant for compounds in relatively wide range of lipophilicity.The dissociation constant value for simpler chemical compounds can be determined via only 8 chromatographic runs.The Yasuda‐Shedlovsky extrapolation that includes several pKa determinations in solutions with different methanol content is not required.Suitable for evaluation of large series of compounds, which can be provided as crude mixtures. ABSTRACT The proposed HPLC method using solely or nearly 100% aqueous mobile buffer as mobile phase offers fast determination of dissociation constant for compounds in relatively wide range of lipophilicity (log P from −2.26 to 2.26). The dissociation constant value for simpler chemical compounds can be determined via only 8 chromatographic runs. The number of needed chromatographic separations depends on the structural complexity of the tested compound. Moreover, the proposed method does not require a measurement of Yasuda‐Shedlovsky extrapolation that includes several pKa determinations in solutions with different methanol content which speeds up considerably the procedure. The methodology is suitable for evaluation of large series of drug candidates, which can be present as complex mixtures and in small amounts.

Fluorescence Properties of Selected Benzo[c]phenanthridines

The fluorescence properties of selected benzo[c]phenanthridines (BPs) were examined. The effect of structure, pH and solvent on the fluorescence properties has been investigated. It was found out that the presence of charged iminium nitrogen significantly decreased the fluorescence of the compounds. The fluorescence (intensity as well as emission spectra shape) of the investigated compounds was significantly dependent on pH as well as used solvent. The utilization in epigenetic modification mechanisms studies as demethylase probe and as possible pH indicator was suggested.

Abstract 5100: AB61, a new potent nucleoside cytostatic: Molecular mechanisms of action and preclinical activity

7-(2-Thienyl)-7-deazaadenosine (AB61) showed nanomolar cytotoxic activities against various cancer cell lines but only mild (micromolar) activities against normal fibroblasts. The selectivity of AB61 was found to be due to inefficient phosphorylation of AB61 in normal fibroblasts. The phosphorylation of AB61 in the leukemic CCRF-CEM cell line proceeds well and it was shown that AB61 is incorporated into both DNA and RNA, preferentially as a ribonucleotide. It was further confirmed that a triphosphate of AB61 is a substrate for both RNA and DNA polymerases in enzymatic assays. Gene expression analysis suggests that AB61 affects DNA damage pathways and protein translation/folding machinery. Indeed, the formation of large 53BP1 foci was observed in nuclei of AB61-treated U2OS-GFP-53BP1 cells indicating DNA damage. Random incorporation of AB61 into RNA blocked its translation in an in vitro assay and reduction of reporter protein expression was also observed in mice after 4-hour treatment with AB61. AB61 also significantly reduced tumor volume in mice bearing SK- OV-3, BT-549, HT-29 and MDA-MB231 xenografts. The results indicate that AB61 is a promising compound with the unique mechanism of action and deserves further development as an anticancer agent. This work was supported by the Ministry of Education of the Czech Republic (LO1304). Citation Format: Petr Dzubak, Marian Hajduch, Pavla Perlikova, Gabriela Rylova, Petr Naus, Tomas Elbert, Eva Tloustova, Aurelie Bourderioux, Lenka Slavetinska, Kamil Motyka, Dalibor Dolezal, Pawel Znojek, Alice Nova, Monika Harvanova, Michal Siler, Jan Hlavac, Michal Hocek. AB61, a new potent nucleoside cytostatic: Molecular mechanisms of action and preclinical activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5100. doi:10.1158/1538-7445.AM2017-5100