Synthesis and biological evaluation of biotin-conjugated anticancer thiosemicarbazones and their iron(III) and copper(II) complexes

Author(s)
Sebastian Kallus, Lukas Uhlik, Sushilla van Schoonhoven, Karla Pelivan, Walter Berger, Eva A. Enyedy, Thilo Hofmann, Petra Heffeter, Christian R. Kowol, Bernhard K. Keppler
Abstract

Triapine, the most prominent anticancer drug candidate from the substance class of thiosemicarbazones, was investigated in > 30 clinical phase I and II studies. However, the results were rather disappointing against solid tumors, which can be explained (at least partially) due to inefficient delivery to the tumor site. Hence, we synthesized the first biotin-functionalized thiosemicarbazone derivatives in order to increase tumor specificity and accumulation. Additionally, for Triapine and one biotin conjugate the iron(III) and copper(II) complexes were prepared. Subsequently, the novel compounds were biologically evaluated on a cell line panel with different biotin uptake. The metal-free biotin-conjugated ligands showed comparable activity to the reference compound Triapine. However, astonishingly, the metal complexes of the biotinylated derivative showed strikingly decreased anticancer activity. To further analyze possible differences between the metal complexes, detailed physico- and electrochemical experiments were performed. However, neither lipophilicity or complex solution stability, nor the reduction potential or behavior in the presence of biologically relevant reducing agents showed strong variations between the biotinylated and non-biotinylated derivatives (only some differences in the reduction kinetics were observed). Nonetheless, the metal-free biotin-conjugate of Triapine revealed distinct activity in a colon cancer mouse model upon oral application comparable to Triapine. Therefore, this type of biotin-conjugated thiosemicarbazone is of interest for further synthetic strategies and biological studies.

Organisation(s)
Department of Inorganic Chemistry
External organisation(s)
Medizinische Universität Wien, Research Cluster Translational Cancer Therapy Research, University of Szeged
Journal
Journal of Inorganic Biochemistry
Volume
190
Pages
85-97
No. of pages
13
ISSN
0162-0134
DOI
https://doi.org/10.1016/j.jinorgbio.2018.10.006
Publication date
01-2019
Peer reviewed
Yes
Austrian Fields of Science 2012
104003 Inorganic chemistry, 301904 Cancer research, 106002 Biochemistry
Keywords
ASJC Scopus subject areas
Biochemistry, Inorganic Chemistry
Sustainable Development Goals
SDG 3 - Good Health and Well-being
Portal url
https://ucrisportal.univie.ac.at/en/publications/24010d68-2528-4dcb-a0c8-3daf5f2477ec