Metalloporphyrins: Radioprotector and Radiosensitizer

Cancer has become the leading cause of human death in the world, due to its uncontrolled and rapid proliferation properties. Radio and chemotherapy are used in the treatment of almost all types of cancer. They mostly act by increasing the production of reactive oxygen specious (ROS) and free radicals. ROS levels are believed to be higher in cancer cells compared to their normal counterparts this is suggested to be related to cancer cell growth, angiogenesis, and metastasis. Although the cure rate for many types of cancer would be increased by radiation dose escalation, balancing the potential for cure against the risk for normal tissue injury is a complex endeavor. Because normal tissue toxicity during radiotherapy and pathological conditions that include overproduction of unstable oxygen species, efforts are ongoing to develop new radioprotective drugs. Antioxidants is an example of co treatment which has potential to protect normal tissues against radiation-induced damage with increasing IR-induced damage for cancer. Since the discovery of superoxide dimutases (SODs), a family of metalloproteins, it has become clear that these enzymes provide an essential defense against the superoxide radical. Application of native SOD has been limited due to short half-lives, lack of cellular uptake and hypersensitivity. Metal-containing SOD mimetics have now emerged as being especially promising, they have been used for treatment of different kinds of diseases, as cancer. It is believed to protect cells from radiation damage by removing free radicals produced by irradiation. The objective of this review is to summarize the most current metalloporphyrin as an example of SODm in treatment of cancer and in combination with other radio and chemotherapy.