Comparative studies of oxaliplatin-based platinum(IV) complexes in different in vitro and in vivo tumor models

Author(s)
Simone Goeschl, Ekaterina Schreiber-Brynzak, Verena Pichler, Klaudia Cseh, Petra Heffeter, Ute Jungwirth, Michael A. Jakupec, Walter Berger, Bernhard K. Keppler
Abstract

Using platinum(IV) prodrugs of clinically established platinum(II) compounds is a strategy to overcome side effects and acquired resistances. We studied four oxaliplatin-derived platinum(IV) complexes with varying axial ligands in various in vitro and in vivo settings. The ability to interfere with DNA (pUC19) in the presence and absence of a reducing agent (ascorbic acid) was investigated in cell-free experiments. Cytotoxicity was compared under normoxic and hypoxic conditions in monolayer cultures and multicellular spheroids of colon carcinoma cell lines. Effects on the cell cycle were investigated by flow cytometry, and the capacity of inducing apoptosis was confirmed by flow cytometry and Western blotting. The anti-cancer activity of one complex was studied in vivo in immunodeficient and immunocompetent mice, and the platinum levels in various organs and the tumor after treatment were quantified. The results demonstrate that modification of the axial ligands can improve the cytotoxic potency. The complexes are able to interfere with plasmid DNA, which is enhanced by co-incubation with a reducing agent, and cause cell cycle perturbations. At higher concentrations, they induce apoptosis, but generate only low levels of reactive oxygen species. Two of the complexes increase the life span of leukemia (L1210) bearing mice, and one showed effects similar to oxaliplatin in a CT26 solid tumor model, despite the low platinum levels in the tumor. As in the case of oxaliplatin, activity in the latter model depends on an intact immune system. These findings show new perspectives for the development of platinum(IV) prodrugs of the anticancer agent oxaliplatin, combining bioreductive properties and immunogenic aspects.

Organisation(s)
Department of Inorganic Chemistry
External organisation(s)
Medizinische Universität Wien, Institute of Cancer Research
Journal
Metallomics: integrated biometal science
Volume
9
Pages
309-322
No. of pages
14
ISSN
1756-5901
DOI
https://doi.org/10.1039/c6mt00226a
Publication date
03-2017
Peer reviewed
Yes
Austrian Fields of Science 2012
106002 Biochemistry, 106023 Molecular biology
Keywords
ASJC Scopus subject areas
Metals and Alloys, Chemistry (miscellaneous), Biophysics, Biochemistry, Biomaterials
Sustainable Development Goals
SDG 3 - Good Health and Well-being
Portal url
https://ucrisportal.univie.ac.at/en/publications/f12df54d-50a9-421f-9a89-989a76678128