Selective Targeting of Breast Cancer with Radioiodide
Creators: name: University Of California Office Of The President
Publisher: name: University of California Office of the President
publisherIdentifier: https://ror.org/00dmfq477
publisherIdentifierScheme: ROR
Year: 2024

description: Few anti-cancer agents can actually target cells selectively. Thus, current therapies, which poison the entire body in order to treat a small tumor, cause much suffering and usually fail to eradicate the disease. We have developed a novel approach to directly treat breast cancer. Our interest evolved from our recent discovery that the mammary gland harbors an iodide transporter protein capable of delivering radioactive iodide (Nature Medicine, 6:871-8, 2000). This was surprising, because iodide accumulation is primarily associated with the thyroid gland. We found that during lactation the breast concentrates iodide in milk so that, adequate amounts of this dietary element are available to the infant. Since radioiodide is currently used to successfully treat thyroid cancer, we are optimistic that our experiments will directly lead to translational applications in breast cancer. In treating thyroid cancer the patients are evaluated by an iodide tracer scan and receive treatment if their cancer cells can concentrate iodide. Then, treatment consists of taking a capsule by mouth. From a clinical standpoint the side-effects are minimal- these include salivation or gastric irritation and last only a few days. Clearly, there is a pressing need to explore more effective treatments with such low toxicity profiles in breast cancer. 
 
 
 
 
 
 
 
 In this project we will determine whether it is possible to activate the iodide-concentrating capacity of human breast cancers after they have been implanted into immune-deficient mice. This is in ideal model system to explore the future clinical application of using radioiodide to treat breast cancer. 
 
 
 
 
 
 
 
 It is our hypothesis that the iodide transporter of the breast, which is normally functional during lactation, can be activated and experimental human tumors will be selectively destroyed by radioactive iodide. We will also perform experiments to validate this approach without damaging the thyroid gland. The iodide concentrating capacity of these experimental tumors will be modulated with a derivative of vitamin A (retinoic acid) and/or hormones associated with pregnancy and lactation (oxytocin and prolactin). Thyroid hormone supplements will be provided to the mice to purposefully decrease or obliterate the ability of the thyroid gland to absorb any iodide. Thus, we predict that radioactive iodide treatment will be significantly directed to breast cancer cells.
 
 
 
 
 
 
 
 Results from this research will be useful in the formulation of a clinical treatment trial. Creating an experimental mouse model carrying a human breast cancer that accumulates iodide is an important step for testing the feasibility and efficiency of this approach. Unlike other anti-cancer modalities, we envision that radioiodide therapy would be selectively given to patients whose cancers concentrate iodide. Because of the extensive clinical experience in using radioactive iodine to treat thyroid cancer, we think that this novel approach promises to be safe and well tolerated.