Transport mechanism-based drug molecular design: novel camptothecin analogues to circumvent ABCG2-associated drug resistance of human tumor cells.

Article Details

Citation

Copy to clipboard

Ishikawa T, Ikegami Y, Sano K, Nakagawa H, Sawada S

Transport mechanism-based drug molecular design: novel camptothecin analogues to circumvent ABCG2-associated drug resistance of human tumor cells.

Curr Pharm Des. 2006;12(3):313-25.

PubMed ID

16454746 [ View in PubMed

]

Abstract

Acquired and intrinsic drug resistance in cancer is the major obstacle to long-term, sustained patient response to chemotherapy. Irinotecan (CPT-11) is a widely-used potent antitumor drug that inhibits mammalian DNA topoisomerase I (Topo I). However, overexpression of ABCG2 (BCRP/MXR/ABCP) reportedly confers cancer cells resistance to SN-38, the active form of CPT-11. To circumvent the ABCG2-associated drug resistance, we have synthesized and characterized a total of fourteen new camptothecin (CPT) analogues with respect to both the inhibition of Topo I and the substrate specificity of ABCG2. While the lactone E ring is a prerequisite for anticancer activity, modifications of the A or B rings do not significantly affect Topo I inhibition activity. In this context, we have synthesized new CPT analogues with different substitutions at positions 10 or 11 of the A ring. All of the tested CPT analogues strongly inhibited the Topo I activity in a cell-free system. Accordingly, we have examined ATP-dependent transport of those CPT analogues by using plasma membrane vesicles prepared from ABCG2-overexpressing cells. Based on the substrate specificity of ABCG2 thus evaluated, it is strongly suggested that CPT analogues with a hydroxyl group at position 10 or 11 of the A ring are good substrates for ABCG2 and therefore effectively extruded from cancer cells. Thus, hydrogen bond formation is considered to be involved in substrate recognition and/or transport processes of ABCG2. The present study provides a practical approach to discover new CPT-based drugs for the chemotherapy of drug-resistant human cancer.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Irinotecan	DNA topoisomerase 1	Protein	Humans	Yes	Inhibitor	Details
Irinotecan	DNA topoisomerase I, mitochondrial	Protein	Humans	Yes	Inhibitor	Details