The Role of Autophagy in Salivary Gland Dysfunction Following Targeted Head and Neck Radiation
AdvisorLimesand, Kirsten H.
MetadataShow full item record
PublisherThe University of Arizona.
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AbstractHead and neck cancer is one of the most common cancers worldwide. The current standard of care for head and neck cancer includes surgical resection of the tumor followed by chemoradiation. This targeted head and neck radiation causes dysfunction of the salivary glands, which leads to xerostomia, mucositis, dysphagia, dental caries, and malnutrition. These side effects greatly decrease patient quality of life and increase their financial responsibility. Current therapies available to ameliorate these negative side effects are expensive, only provide short-term relief, and many of them have negative side effects of their own. Therefore, another therapy is needed to prevent salivary gland dysfunction or restore its function following targeted head and neck radiation. Autophagy is a homeostatic cellular mechanism that could be targeted as a therapeutic mechanism in the salivary glands following targeted head and neck radiation. Autophagy is a catabolic process necessary to maintain cellular homeostasis. It has been shown to play a beneficial role in a variety of disease states including diabetes mellitus, obesity, and cancer. The role of autophagy in the response of cancerous tissue to radiation has been vastly studied. However, the role autophagy plays in normal tissue response to radiation remains poorly understood and much more research in this area is needed.Atg5^(f/f);Aqp5-Cre mice have a conditional knockout of Atg5, a gene necessary for autophagy, in the salivary glands. These mice have unchanged baseline levels of apoptosis, proliferation, and stimulated salivary flow rates when compared to wild-type mice. Therefore, they are a useful model to investigate the role of autophagy in the response of the salivary glands to targeted head and neck radiation. These Atg5^(f/f);Aqp5-Cre autophagy-deficient mice display increased radiosensitivity following targeted head and neck radiation. Furthermore, post-therapy use of CCI-779, a rapalogue and inducer of autophagy, allowed for restoration of salivary gland function following targeted head and neck radiation. Taken together, these results implicate autophagy as playing a beneficial role in normal salivary function following radiation. Therefore, autophagy could be utilized by normal salivary gland tissue following targeted head and neck radiation to maintain salivary gland function.
Degree ProgramGraduate College