Overview of Cancer Therapeutic Agents Chemotherapy agents can be divided into several categories: alkylating agents (e.g., cyclophosphamide, ifosfamide), antibiotics which affect nucleic acids (e.g., doxorubicin, bleomycin), platinum compounds (e.g., cisplatin), mitotic inhibitors (e.g., vincristine), antimetabolites (e.g., 5-fluorouracil), camptothecin derivatives (e.g., topotecan), biological response modifiers (e.g., interferon), and hormone therapies (e.g., tamoxifen). The agents most noted for creating cellular damage by initiating free radical oxidants are the alkylating agents, the tumor antibiotics, and the platinum compounds. The agents in these categories demand definition concerning interactions with antioxidants which might reduce effectiveness of chemotherapy. There is also the possibility of adverse interaction between antioxidant treatment and agents that do not act via an oxidative mechanism (e.g., 5-fluorouracil or tamoxifen). In addition to the idea that chemotherapy must create a lethal injury to DNA to produce malignant cell death is the mechanism of apoptosis. A dose of chemotherapy which does not produce necrosis can trigger apoptosis, either immediate or delayed. Additionally, anti-apoptotic mutations can result in drug resistance in human tumors. At least one antioxidant (quercetin) has been demonstrated to overcome such an anti-apoptotic blockage.22 Radiotherapy uses ionizing radiation to produce cell death through free radical formation. Two mechanisms are involved. The apoptosis mechanism results in cell death within a few hours of radiation. The second mechanism is radiation-induced failure of mitosis and the inhibition of cellular proliferation, which kills cancer cells. Currently, the principal target of radiation is considered to be cellular DNA. However, studies show the signal for apoptosis can be generated by the effect of radiation on cell membranes, apparently through lipid peroxidation. This suggests an alternate mechanism to the hypothesis that DNA damage is required for cell death.23 Antioxidants in Cancer Therapy; Their Actions and Interactions With Oncologic Therapies Davis W. Lamson, MS, ND and Matthew S. Brignall, ND Alternative Medicine Reviews, 1999;4(5):304-329 Alternative Medicine Reviews, 1999;4(5):304-329 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.