Background:

9-amino Camptothecin is a topoisomerase I inhibitor [1][2].

DNA topoisomerases relax DNA torsional strain generated during replication, transcription, recombination, repair, and chromosome condensation. The relaxation of DNA supercoiling by topoisomerase I is enabled by a mechanism of controlled rotation around a transient DNA single-strand break. Camptothecin (CPT) is isolated from the bark of the Chinese tree Camptotheca accuminata [3].

9-amino Camptothecin, a water-soluble camptothecin analogue, is a topoisomerase I inhibitor. In human HT-29 colon adenocarcinoma, 9-amino Camptothecin (9-AC) exhibited cytotoxicity with IC50 value of 19 nM. 9-AC also induced DNA damage in whole cells and nuclei at a concenstration of 85 nM and 21 nM, respectively [1].

9-amino Camptothecin had greater activity than camptothecin against human tumour xenografts, including Lewis lung carcinoma and B16 melanoma. 9-AC had entered phase II trials. In patients with advanced solid tumours, 9-amino Camptothecin exhibited anti-tumor activity [1][2].

参考文献:
[1].  Rothenberg, M.L. Topoisomerase I inhibitors: Review and update. Annals of Oncology 8(9), 837-855 (1997).
[2].  Dancey J, Eisenhauer EA. Current perspectives on camptothecins in cancer treatment. Br J Cancer. 1996 Aug;74(3):327-38.
[3].  Drwal MN1, Agama K, Wakelin LP, et al. Exploring DNA topoisomerase I ligand space in search of novel anticancer agents. PLoS One. 2011;6(9):e25150.