Colorectal carcinoma is the third leading cause of cancer related mortality within the United States. Over 90% of these deaths can be attributed to distant metastasis. Therefore, understanding the signaling perturbations that underlie the development of carcinoma and process of metastasis are paramount in combatting the progression of this disease. Many signaling pathways are dysregulated in the pathogenesis of colorectal carcinoma, but over 80% of sporadic colorectal cancer cases have alterations within the WNT pathway, and over 50% within the TGF-β signaling pathway. Both the WNT and TGF-β pathways are critical in development and intestinal homeostasis. The central mediator of TGF-β signaling pathway is Smad4, a transcription factor that is mutated in approximately 15-30% of colorectal cancer cases. Loss of Smad4 is associated with distant metastasis and overall poor patient prognosis. This body of work uses both in vitro and in vivo models to describe a role for Smad4 in supporting normal epithelial homeostasis within the intestinal tract. These models also describe a new tumor suppressor role of Smad4 wherein Smad4 signaling transcriptionally suppresses WNT pathway activation within intestinal epithelial cells. Overall, these results aid in understanding the biological function of Smad4 signaling in the context of intestinal homeostasis and tumorigenesis and permit further insight into potential therapeutic targets in colorectal carcinoma.
| Identifer | oai:union.ndltd.org:VANDERBILT/oai:VANDERBILTETD:etd-07292014-141638 |
| Date | 31 July 2014 |
| Creators | Freeman, Tanner John |
| Contributors | Steve Hann, Anna Means, PhD, Ethan Lee, MD/PhD, James Goldenring, MD/PhD |
| Publisher | VANDERBILT |
| Source Sets | Vanderbilt University Theses |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.vanderbilt.edu/available/etd-07292014-141638/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Vanderbilt University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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