Health Dictionary
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Topoisomerase inhibitor
Introduction
Overview
Topoisomerase inhibitors are chemotherapy agents designed to interfere with the action of topoisomerase enzymes (topoisomerase I and II), which are enzymes that control the changes in DNA structure by catalyzing the breaking and rejoining of the phosphodiester backbone of DNA strands during the normal cell cycle.
In recent years, topoisomerase inhibitors have become popular targets for cancer chemotherapy treatments. It is thought that topoisomerase inhibitors block the ligation step of the cell cycle, and that topoisomerase I and II inhibitors interfere with the transcription and replication of DNA by upsetting proper DNA supercoiling.
A commonly prescribed class of topoisomerase inhibitors are fluoroquinolones.
- Topoisomerase I inhibitors: irinotecan, topotecan, camptothecin and lamellarin D
- Topoisomerase II inhibitors: amsacrine, etoposide, etoposide phosphate, teniposide and doxorubicin
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]