Half-Sandwich Rhodium Complexes with Releasable N-Donor Monodentate Ligands: Solution Chemical Properties and the Possibility for Acidosis Activation
- Author(s)
- János P. Mészáros, Wolfgang Kandioller, Gabriella Spengler, Alexander Prado-Roller, Bernhard K. Keppler, Éva A. Enyedy
- Abstract
Cancer chemotherapeutics usually have serious side effects. Targeting the special properties of cancer and activation of the anticancer drug in the tumor microenvironment in situ may decrease the intensity of the side effects and improve the efficacy of therapy. In this study, half-sandwich Rh complexes are introduced, which may be activated at the acidic, extracellular pH of the tumor tissue. The synthesis and aqueous stability of mixed-ligand complexes with a general formula of [Rh(η5-Cp*)(N,N/O)(N)]2+/+ are reported, where (N,N/O) indicates bidentate 8-quinolate, ethylenediamine and 1,10-phenanthroline and (N) represents the releasable monodentate ligand with a nitrogen donor atom. UV-visible spectrophotometry, 1H NMR, and pH-potentiometry were used to determine the protonation constants of the monodentate ligands, the proton dissociation constants of the coordinated water molecules in the aqua complexes, and the formation constants of the mixed-ligand complexes. The obtained data were compared to those of the analogous Ru(η6-p-cymene) complexes. The developed mixed-ligand complexes were tested in drug-sensitive and resistant colon cancer cell lines (Colo205 and Colo320, respectively) and in four bacterial strains (Gram-positive and Gram-negative, drug-sensitive, and resistant) at different pH values (5–8). The mixed-ligand complexes with 1-methylimidazole displayed sufficient stability at pH 7.4, and their activation was found in cancer cells with decreasing pH; moreover, the mixed-ligand complexes demonstrated antimicrobial activity in Gram-positive and Gram-negative bacteria, including the resistant MRSA strain. This study proved the viability of incorporating releasable monodentate ligands into mixed-ligand half-sandwich complexes, which is supported by the biological assays.
- Organisation(s)
- Department of Inorganic Chemistry, Core Facility Crystal Structure Analysis
- External organisation(s)
- University of Szeged, Research Cluster Translational Cancer Therapy Research
- Journal
- Pharmaceutics
- Volume
- 15
- DOI
- https://doi.org/10.3390/pharmaceutics15020356
- Publication date
- 02-2023
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 301207 Pharmaceutical chemistry, 301904 Cancer research, 301206 Pharmacology
- Keywords
- ASJC Scopus subject areas
- Pharmaceutical Science
- Sustainable Development Goals
- SDG 3 - Good Health and Well-being
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/4e7cc4e2-85aa-402d-ba57-d1feb74de946