5.2. Mode of action
The main mode of action of camptothecin against cancer cells includes
binding with topoisomerase I to form a cleavable complex in-between DNA
strands. Topoisomerase I involve in the unwinding of DNA strands during
replication and ligation of DNA after replication. CPT inhibits the
re-ligation function of topoisomerase I by forming a stable complex with
it (Liu et al., 2015a) (Fig.
11 ).