Camptothecin (CPT) is a monoterpenoid indole alkaloid originally isolated from Camptotheca acuminata Decne, a deciduous tree native to south China. Irinotecan (CPT-11) and topotecan (TPT), two water-soluble derivatives of CPT, have gained approval by the Food and Drug Administration of the United States of America (FDA) for treating colorectal and ovarian cancer. Other camptothecins--such as 9-aminocamptothecin (9AC), 9-nitrocamptothecin (9NC), and 7-(4-methyl piperazino-methylene)-10,11-ethylenedioxycamptothecin (GG211)--have also showed remarkable potential in the treatment of carcinoma. Camptothecins are lauded as one of the most promising anticancer drugs of the twenty-first century.
Camptothecin and derivative of camptothecin are known as inhibitors,that of nucleat topoisomerase I by binding to and trapping the topoisomerase-DNA covalent complex,so cancer cells are killed. Camptothecin is a potent broad spectrum antitumor agent which is of interest due to a variety of camptothecin derivatives currently being used in a variety of clinical protocols. Camptothecin functions by effectively converting DNA topoisomerase I into a DNA damaging poison, causing it to irreversibly bind DNA midway through its catalytic action, leading to a double-stranded break when encountered by a replication fork. We have found that cells containing a mutant histone H4 compromised for N-terminal acetylation become hypersensitive to killing by camptothecin.
Camptothecin and its derivatives are active against carcinomas of the stomach, colon, head, neck and bladder. Camptothecin and derivative of camptothecin exhibited remarkable antitumour and antileukaemia activity,its are in clinical trials to treat breast and coloncancers,small-cell lung cancer and leukemia etc.though camptothecin is limited because of serious side effects and poor water-solubity in clinic,either semi-synthetic or synthetic camptothecin drug(such as FDA approved irinptecan and topotecan)are satisfactory in curative effects.