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.