Topoisomerase Inhibitors and Targeted Delivery in Cancer Therapy

DNA topoisomerases are enzymes that catalyze the alteration of DNA topology with transiently induced DNA strand breakage, essential for DNA replication. Topoisomerases are validated cancer chemotherapy targets. Anticancer agents targeting Topoisomerase I and II have been in clinical use and proven to be highly effective, though with significant side effects. There are tremendous efforts to develop new generation of topoisomerase inhibitors. Targeted delivery of topoisomerase inhibitors is another way to reduce the side effects. Conjugates of topoisomerases inhibitors with antibody, polymer, or small molecule are developed to target these inhibitors to tumor sites.