Abstract
Determination of the DNA-binding reactivity and affinity is an important part of a successful program for the selection of metallodrug candidates. For such assaying, a range of complementary analytical techniques was proposed and tested here using one of few anticancer metal-based drugs that are currently in clinical trials, indazolium trans-[tetrachloridobis(1H-indazole)ruthenate(III), and a DNA oligonucleotide. A high reactivity of the Ru drug was confirmed in affinity capillary electrophoresis (CE) mode, where adduct formation takes place in situ (i.e., in the capillary filled with an oligonucleotide-containing electrolyte). To further characterize the binding kinetics, a drug–oligonucleotide mixture was incubated for a different period of time, followed by ultrafiltration separation into two different in molecular weight fractions (>3 and <3 kDa). The time-dependent distribution profiles of the Ru drug were then assessed by CE-inductively coupled plasma mass spectrometry (ICP-MS), revealing that at least two DNA adducts exist at equilibrium conditions. Using standalone ICP-MS, dominant equilibrium amount of the bound ruthenium was found to occur in a fraction of 5–10 kDa, which includes the oligonucleotide (ca. 6 kDa). Importantly, in all three assays, the drug was used for the first time in in-vitro studies, not in the intact form but as its active species released from the transferrin adduct at simulated cancer cytosolic conditions. This circumstance makes the established analytical platform promising to provide a detailed view on metallodrug targeting, including other possible biomolecules and ex vivo samples.
Highlights
Anticancer metallodrugs seem to have a great many targets such as DNA, proteins, membranes, etc
According to the most often quoted concept of transportation, the drug enters the cell via transferrin route, being bound to this protein
A recent systematic study carried out in our laboratories focused on intracellular activation chemistry of a given Ru drug, including cancer cytosol environment [18,19,20]
Summary
Anticancer metallodrugs seem to have a great many targets such as DNA, proteins, membranes, etc. The true lesion responsible for the biological activity of a drug is difficult to determine. This is because metal complexes are naturally diversely reactive species. There are at least two additional obstacles. Analytical techniques and tools being used to map interactions with different pertinent biomolecules are not always of the metallomic origin and, as such, incapable to identify, characterize, and quantify metal species stemmed from binding. The path taken by a metal complex in reaching its target and accompanying changes in metal speciation are typically downplayed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
