Topoisomerase Inhibitors Quiz

Camptothecin Mechanism of Action

• Camptothecin inhibits cancer cell replication by targeting and inhibiting topoisomerase I.
• It stabilizes the DNA-topoisomerase I complex after it cleaves the DNA strand, preventing the ligation reaction and leading to DNA damage.
• The accumulation of DNA breaks disrupts replication and transcription processes, ultimately triggering cell death.

Etoposide Mechanism of Action

• Etoposide inhibits cancer cell replication by targeting topoisomerase II.
• It interferes with the enzyme's ability to seal the double-stranded breaks it induces in DNA, leading to DNA damage accumulation.
• This damage results in cell cycle arrest and apoptosis in rapidly dividing cancer cells.

Topoisomerase Inhibition

• Camptothecin specifically inhibits topoisomerase I, which is responsible for relieving torsional strain in DNA during replication.
• Etoposide specifically inhibits topoisomerase II, which is responsible for managing DNA tangles and breaks during the replication process.

Primary Uses

• Camptothecin is primarily used in the treatment of various types of cancer, including colorectal and lung cancers.
• Etoposide is commonly used for treating testicular cancer, small cell lung cancer, and as part of combination chemotherapy regimens for several malignancies.