Aurelie Bourderioux

Synthesis and Significant Cytostatic Activity of 7-Hetaryl-7-deazaadenosines

A series of 7-aryl- and 7-hetaryl-7-deazaadenosines was prepared by the cross-coupling reactions of unprotected or protected 7-iodo-7-deazaadenosines with (het)arylboronic acids, stannanes, or zinc halides. Nucleosides bearing 5-membered heterocycles at the position 7 exerted potent in vitro antiproliferative effects against a broad panel of hematological and solid tumor cell lines. Cell cycle analysis indicated profound inhibition of RNA synthesis and induction of apoptosis in treated cells. Intracellular conversion to triphosphates has been detected with active compounds. The triphosphate metabolites showed only a weak inhibitory effect on human RNA polymerase II, suggesting potentially other mechanisms for the inhibition of RNA synthesis and quick onset of apoptosis. Initial in vivo evaluation demonstrated an effect of 7-(2-thienyl)-7-deazaadenine ribonucleoside on the survival rate in syngeneic P388D1 mouse leukemia model.

The glucosinolate–myrosinase system. New insights into enzyme–substrate interactions by use of simplified inhibitors

Myrosinase, a thioglucoside glucohydrolase, is the only enzyme able to hydrolyse glucosinolates, a unique family of molecules bearing an anomeric O-sulfated thiohydroximate function. Non-hydrolysable myrosinase inhibitors have been devised and studied for their biological interaction. Diverse modifications of the O-sulfate moiety did not result in a significant inhibitory effect, whereas replacing the D-glucopyrano residue by its carba-analogue allowed inhibition to take place. X-Ray experiments carried out after soaking allowed for the first time inclusion of a non-hydrolysable inhibitor inside the enzymatic pocket. Structural tuning of the aglycon part in its pocket is being used as a guide for the development of simplified and more potent inhibitors.

Structural Basis for Inhibition of Mycobacterial and Human Adenosine Kinase by 7-Substituted 7-(Het)aryl-7-deazaadenine Ribonucleosides

Adenosine kinase (ADK) from Mycobacterium tuberculosis (Mtb) was selected as a target for design of antimycobacterial nucleosides. Screening of 7-(het)aryl-7-deazaadenine ribonucleosides with Mtb and human (h) ADKs and testing with wild-type and drug-resistant Mtb strains identified specific inhibitors of Mtb ADK with micromolar antimycobacterial activity and low cytotoxicity. X-ray structures of complexes of Mtb and hADKs with 7-ethynyl-7-deazaadenosine showed differences in inhibitor interactions in the adenosine binding sites. 1D (1)H STD NMR experiments revealed that these inhibitors are readily accommodated into the ATP and adenosine binding sites of Mtb ADK, whereas they bind preferentially into the adenosine site of hADK. Occupation of the Mtb ADK ATP site with inhibitors and formation of catalytically less competent semiopen conformation of MtbADK after inhibitor binding in the adenosine site explain the lack of phosphorylation of 7-substituted-7-deazaadenosines. Semiempirical quantum mechanical analysis confirmed different affinity of nucleosides for the Mtb ADK adenosine and ATP sites.

Synthesis and biological evaluation of novel oxophenylarcyriaflavins as potential anticancer agents.

We report the synthesis and biological evaluation of new oxophenylarcyriaflavins designed as potential anticancer agents. An efficient synthesis involving palladium-catalyzed Suzuki and Stille reactions is presented, without any indolic protective group. The central ring closure of the scaffold was performed through an electrophilic reaction on the position C-2 of the indole ring. The use of indole and 5-benzyloxyindole, along with substituted phenyl rings, generated three different scaffolds, which were successively exploited to modulate the structure. The cytotoxicity of the newly designed compounds on four cancer cell lines and activities against three kinases (CDK1, CDK5 and GSK3) were evaluated. Several compounds showed a marked cytotoxicity with IC(50) values in the sub-micromolar range, and induced important cell cycle perturbations, with a G2/M arrest. Some compounds revealed DNA binding properties and were found to inhibit topoisomerase-mediated DNA relaxation of supercoiled DNA, but these properties are not mandatory for a cytotoxic action. A novel lead compound () has been identified and warrants further investigations.

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.

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