Preclinical characterization of anticancer gallium(III) complexes: solubility, stability, lipophilicity and binding to serum proteins

Author(s)
Andrei Timerbaev, Alexander V. Rudnev, Lidia S. Foteeva, Christian Kowol, Roland Berger, Michael Jakupec, Vladimir Arion, Bernhard Keppler
Abstract

The discovery and development of gallium(III) complexes capable of inhibiting tumor growth is an emerging area of anticancer drug research. A range of novel gallium coordination compds. with established cytotoxic efficacy have been characterized in terms of desirable chem. and biochem. properties and compared with tris(8-quinolinolato)gallium(III) (KP46), a lead anticancer gallium-based candidate that successfully finished phase I clin. trials (under the name FFC11), showing activity against renal cell cancer. In view of probable oral administration, drug-like parameters, such as soly. in water, saline and 0.5% DMSO, stability against hydrolysis, measured as the rate const. of hydrolytic degrdn. in water or physiol. buffer using a capillary zone electrophoresis (CZE) assay, and the octanol-water partition coeff. (log P) providing a rational est. of a drug's lipophilicity, have been evaluated and compared. The differences in bioavailability characteristics between different complexes were discussed within the formalism of structure-activity relationships. The reactivity toward major serum transport proteins, albumin and transferrin, was also assayed in order to elucidate the drug's distribution pathway after intestinal absorption. According to the values of apparent binding rate consts. detd. by CZE, both KP46 and bis(2-acetylpyridine-4,4-dimethyl-3-thiosemicarbazonato-N,N,S)gallium(III) tetrachlorogallate(III) (KP1089) bind to transferrin faster than to albumin. This implies that transferrin would rather mediate the accumulation of gallium antineoplastic agents in solid tumors. A tendency of being faster converted into the protein-bound form found for KP1089 (due possibly to non-covalent binding) seems complementary to its greater in vitro antiproliferative activity.

Organisation(s)
Department of Inorganic Chemistry
External organisation(s)
Russian Academy of Sciences
Journal
Journal of Inorganic Biochemistry
Volume
100
Pages
1819-1826
No. of pages
8
ISSN
0162-0134
Publication date
2006
Peer reviewed
Yes
Austrian Fields of Science 2012
1040 Chemistry
Sustainable Development Goals
SDG 3 - Good Health and Well-being
Portal url
https://ucrisportal.univie.ac.at/en/publications/a6768f6a-d033-411f-a82d-809837330892