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Published on: December 1, 2016
Topoisomerases as anticancer targets
Justine L Delgado1, Chao-Ming Hsieh2, Nei-Li Chan2
1Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, College of Pharmacy, University of Iowa, 115 S Grand Ave., S321 Pharmacy Building, Iowa City, IA 52242, U.S.A.
Abstract:
Many cancer type-specific anticancer agents have been developed and significant advances have been made toward precision medicine in cancer treatment. However, traditional or nonspecific anticancer drugs are still important for the treatment of many cancer patients whose cancers either do not respond to or have developed resistance to cancer-specific anticancer agents. DNA topoisomerases, especially type IIA topoisomerases, are proved therapeutic targets of anticancer and antibacterial drugs. Clinically successful topoisomerase-targeting anticancer drugs act through topoisomerase poisoning, which leads to replication fork arrest and double-strand break formation. Unfortunately, this unique mode of action is associated with the development of secondary cancers and cardiotoxicity. Structures of topoisomerase-drug-DNA ternary complexes have revealed the exact binding sites and mechanisms of topoisomerase poisons. Recent advances in the field have suggested a possibility of designing isoform-specific human topoisomerase II poisons, which may be developed as safer anticancer drugs. It may also be possible to design catalytic inhibitors of topoisomerases by targeting certain inactive conformations of these enzymes. Furthermore, identification of various new bacterial topoisomerase inhibitors and regulatory proteins may inspire the discovery of novel human topoisomerase inhibitors. Thus, topoisomerases remain as important therapeutic targets of anticancer agents.
Insights
DNA topoisomerases are crucial targets for anticancer drugs. Research explores developing safer, isoform-specific topoisomerase II inhibitors and novel catalytic inhibitors to overcome current treatment limitations.
Area of Science:
- Biochemistry
- Pharmacology
- Oncology
Background:
- Precision medicine advances cancer treatment, but traditional anticancer agents remain vital for resistant or unresponsive cancers.
- DNA topoisomerases, particularly type IIA, are validated targets for anticancer and antibacterial drugs.
- Current topoisomerase poisons cause DNA damage but are linked to severe side effects like secondary cancers and cardiotoxicity.
Purpose of the Study:
- To review the role of topoisomerases as therapeutic targets in cancer treatment.
- To explore novel strategies for developing safer and more effective topoisomerase-targeting anticancer agents.
- To discuss the potential of designing isoform-specific inhibitors and catalytic inhibitors.
Main Methods:
- Review of existing literature on topoisomerase function, drug mechanisms, and structural biology.
- Analysis of structure-drug-DNA ternary complexes to understand poison binding sites.
- Exploration of recent advances in inhibitor design and discovery.
Main Results:
- Topoisomerase poisoning leads to replication fork arrest and DNA double-strand breaks, forming the basis of current drug action.
- Structural studies elucidate the precise mechanisms of topoisomerase poisons.
- Emerging strategies include designing isoform-specific human topoisomerase II poisons and catalytic inhibitors targeting inactive enzyme conformations.
Conclusions:
- Topoisomerases continue to be significant therapeutic targets for novel anticancer drug development.
- Developing isoform-specific inhibitors and catalytic inhibitors holds promise for safer and more effective cancer therapies.
- Insights from bacterial topoisomerase research may inspire new human topoisomerase inhibitor discovery.
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