Topoisomerase inhibitor

Topoisomerase inhibitors are chemotherapeutic agents that interfere with the action of topoisomerase enzymes (topoisomerase I and II), which are crucial in DNA replication. These inhibitors can be divided into two groups: topoisomerase I inhibitors and topoisomerase II inhibitors.

Topoisomerase I inhibitors

Topoisomerase I inhibitors include camptothecin analogs. They work by stabilizing the complex of topoisomerase I and DNA, preventing the re-ligation of the DNA strand and leading to DNA damage.

Camptothecin analogs

• Irinotecan: Used in the treatment of colorectal cancer.
• Topotecan: Used in the treatment of ovarian cancer, cervical cancer, and small cell lung cancer.

Topoisomerase II inhibitors

Topoisomerase II inhibitors can be further divided into two groups: those that work by stabilizing the topoisomerase II complex (e.g., etoposide, teniposide) and those that work by intercalating into DNA and inhibiting topoisomerase II (e.g., anthracyclines, mitoxantrone).

Etoposide and teniposide

• Etoposide: Used in the treatment of testicular cancer, small cell lung cancer, and lymphomas.
• Teniposide: Used in the treatment of leukemia.

Anthracyclines and mitoxantrone

• Doxorubicin: Used in the treatment of a wide range of cancers, including breast cancer, lung cancer, ovarian cancer, and lymphomas.
• Mitoxantrone: Used in the treatment of prostate cancer and multiple sclerosis.

See also

• DNA replication
• Chemotherapy
• Cancer