Anthracyclines are a class of drugs used in cancer chemotherapy that are extracted from Streptomyces bacterium. These compounds are used to treat many cancers, including leukemias, lymphomas, breast, stomach, uterine, ovarian, bladder cancer, and lung cancers. The first anthracycline discovered was daunorubicin (trade name Daunomycin), which is produced naturally by Streptomyces peucetius, a species of actinobacteria. Clinically the most important anthracyclines are doxorubicin, daunorubicin, epirubicin and idarubicin.The anthracyclines are among the most effective anticancer treatments ever developed and are effective against more types of cancer than any other class of chemotherapeutic agents. Their main adverse effect is cardiotoxicity, which considerably limits their usefulness. Use of anthracyclines has also been shown to be significantly associated with cycle 1 severe or febrile neutropenia. Other adverse effects include vomiting.
The drugs act mainly by intercalating with DNA and interfering with DNA metabolism and RNA production. Cytotoxicity is primarily due to inhibition of topoisomerase II after the enzyme induces a break in DNA, preventing religation of the break and leading to cell death. The basic structure of anthracyclines is that of a tetracyclic molecule with an anthraquinone backbone connected to a sugar moiety by a glycosidic linkage. When taken up by a cell the four ring structure intercalates between DNA bases pairs while the sugar sits within the minor groove and interacts with adjacent base pairs.