Over 1 million new cases of cancer are diagnosed each year, according to the American Cancer Society. A common and effective treatment option is chemotherapy, which is the use of chemical agents designed to kill the rapidly dividing cancer cells. Many classes of chemotherapy agents exist, each designed to target and stop a specific enzyme, protein or process of cancer cells.
Alkylating Agents
Alkylating agents are a type of chemotherapy drug used as treatment for a variety of different cancers. The drugs function to damage DNA by adding specific chemical groups or causing functional disruptions in the DNA backbone. This prevents the cancer cells from reproducing leading to cell death. The most common cancers treated with alkylating agents include leukemia and lymphoma, sarcomas, multiple myelomas, and cancers of the breast, lung and ovaries. Many types of alkylating agents exist, such as nitrogen mustards or alkyl sulfonates, which vary based upon their mechanism of action. Long-term use of alkylating agents poses the risk of bone marrow damage.
Antimetabolites
Antimetabolites function in the body to disrupt the growth of either RNA or DNA strands. The drugs act to displace the normal building blocks of RNA or DNA with nonfunctional substitutes that prevent cellular reproduction and thus cell growth. This class of drugs is most commonly used to treat leukemia, breast cancer, ovarian cancer and cancer of the intestinal tract. Antimetabolites are classified and named based upon their cellular target. such as folate, purine or pyrimidine antagonists.
Anthracyclines
Also called anti-tumor antibiotics, anthracyclines are a type of chemotherapy drug used in a wide variety of cancers. The mechanism by which these drugs work is to interfere with specific enzymes that are vital to the successful replication of DNA in cancer cells. The drugs come from a certain type of bacteria called Streptomyces. A high number of cancers have been shown to be responsive to anthracycline chemotherapy, but they have been shown to cause heart damage in high doses and thus dosages must be carefully controlled, according to the American Cancer Society.
Topoisomerase Inhibitors
Topoisomerase is an enzyme in the cells of the body that functions to wind and unwind DNA for the purpose of cellular replication and growth. The class of chemotherapy drugs referred to as topoisomerase inhibitors function to inhibit this enzyme, thus shutting down the mechanism by which DNA strands are able to be copied for replication. Leukemia, lung and ovarian cancer, and cancers of the gastrointestinal tract are most often treated with topoisomerase inhibitors.
Mitotic Inhibitors
A class of chemotherapy agents called mitotic inhibitors function in the body to inhibit certain enzymes that are vital to a process of cell growth called mitosis. Breast cancer, lung cancer, myelomas and lymphomas are the most common types of cancers treated with mitotic inhibitors. These types of drugs are often derived from plant alkaloids or other types of natural products. Peripheral nerve damage is one significant drawback to this type of drug thus leading to dosage limits.
