Understanding the metabolism of the anticancer drug Triapine

Author(s)
Karla Pelivan, Lisa Frensemeier, Uwe Karst, Gunda Koellensperger, Bjoern Bielec, Sonja Hager, Petra Heffeter, Bernhard K. Keppler, Christian R. Kowol
Abstract

α-N-Heterocyclic thiosemicarbazones are among the most promising ribonucleotide reductase inhibitors identified so far. Triapine, the most prominent representative of this class of substances, has been investigated in multiple phase I and II clinical trials. With regard to clinical practice, Triapine showed activity against hematological diseases, but ineffectiveness against a variety of solid tumors. However, the reasons are still vague and the amount of ADME (absorption, distribution, metabolism and excretion) data for Triapine available in the literature is very limited. Therefore, different analytical tools were used to investigate the metabolism of Triapine including electrochemical oxidations, liver microsomes and in vivo samples from mice. The main metabolic reactions, observed by all three methods, were dehydrogenation and hydroxylations, confirming that electrochemistry, as a purely instrumental approach, can be applied for the simulation of metabolic pathways. The dehydrogenated metabolite M1 was identified as a thiadiazole ring-closed oxidation product of Triapine. From a biological point of view, M1, as a key metabolite, is of interest since the crucial chemical property of α-N-heterocyclic thiosemicarbazones to bind metal ions is lost and cytotoxicity studies showed no anticancer activity of M1. The in vivo data of the urine samples revealed very high levels of the metabolites and Triapine itself already 15 min after treatment. This clearly indicates that Triapine is rapidly metabolised and excreted, which represents an important step forward to understand the possible reason for the inefficiency of Triapine against solid tumors.

Organisation(s)
Department of Inorganic Chemistry, Department of Analytical Chemistry, Mass Spectrometry Centre
External organisation(s)
Universität Münster, Medizinische Universität Wien
Journal
The Analyst
Volume
142
Pages
3165-3176
No. of pages
12
ISSN
0003-2654
DOI
https://doi.org/10.1039/c7an00902j
Publication date
09-2017
Peer reviewed
Yes
Austrian Fields of Science 2012
301904 Cancer research, 104002 Analytical chemistry
Keywords
ASJC Scopus subject areas
Analytical Chemistry, Biochemistry, Spectroscopy, Electrochemistry, Environmental Chemistry
Sustainable Development Goals
SDG 3 - Good Health and Well-being
Portal url
https://ucrisportal.univie.ac.at/en/publications/1b1f467b-0685-4aa5-ab4f-d0262c4460ed