Inhibition of Topoisomerases by Metal Thiosemicarbazone Complexes.

Topoisomerases, common targets for anti-cancer therapeutics, are crucial enzymes for DNA replication, transcription, and many other aspects of DNA metabolism. The potential anti-cancer effects of thiosemicarbazones (TSC) and metal-TSC complexes have been demonstrated to target several biological processes, including DNA metabolism. Human topoisomerases were discovered among the molecular targets for TSCs, and metal-chelated TSCs specifically displayed significant inhibition of topoisomerase II.

Clarifying the Mechanism of Copper(II) α-(N)-Heterocyclic Thiosemicarbazone Complexes on DNA Topoisomerase IIα and IIβ.

Topoisomerase II is a nuclear enzyme involved in the maintenance of DNA and is an effective anticancer drug target. However, several clinical topoisomerase II-targeted agents display significant off-target toxicities and adverse events. Thus, it is important to continue characterizing compounds with activity against topoisomerase II.

Structural and Metal Ion Effects on Human Topoisomerase IIα Inhibition by α-(N)-Heterocyclic Thiosemicarbazones.

Our previous research has shown that α-(N)-heterocyclic thiosemicarbazone (TSC) metal complexes inhibit human topoisomerase IIα (TopoIIα), while the ligands without metals do not. To find out the structural elements of TSC that are important for inhibiting TopoIIα, we have synthesized two series of α-(N)-heterocyclic TSCs with various substrate ring segments, side chain substitutions, and metal ions, and we have examined their activities in TopoIIα-mediated plasmid DNA relaxation and cleavage assays. Our goal is to explore the structure-activity relationship of α-(N)-heterocyclic TSCs and their effect on TopoIIα.

Examination of the Impact of Copper(II) α-(N)-Heterocyclic Thiosemicarbazone Complexes on DNA Topoisomerase IIα.

Type II DNA topoisomerases resolve topological knots and tangles in DNA that result from routine cellular processes and are effective targets for anticancer therapeutics. To this end, thiosemicarbazones have been identified as having the ability to kill cancer cells from several cell lines. Literature evidence suggests that at least some thiosemicarbazones have an impact on topoisomerase II activity.