In my training thus far, I have successfully completed several clinical and outcomes research projects, resulting in publications. Yet during my year as the Chief Resident in internal medicine at Duke, the unexpected began to happen: I became increasingly interested in basic research questions. Because we seemed unable to positively impact the rate of esophageal cancer development, my curiosity grew about the molecular events behind pre-malignant disease in the gastrointestinal tract. I began to consider how a better understanding of the basic esophageal biology might translate into much needed advances in patient screening, surveillance and risk-stratification. This yearning for deeper biologic understanding has driven the formation of the proposed project and mentoring team. Esophageal cancer has a five-year survival of less than 17%, and esophageal adenocarcinoma (EAC) now comprises more than 50% of esophageal cancer cases. Current screening efforts have failed to impact mortality. In order to improve survival, new strategies for prevention and early detection are needed. The squamous progenitor cells in the basal layer of the esophageal squamous epithelium and at the squamo-columnar junction have been extensively studied. In humans, progenitors for high-risk BE and EAC may be different (perhaps less differentiated) than the basal squamous epithelial progenitor, and this human esophageal progenitor may be located deeper in the submucosa than the cells found at the squamo-columnar junction in mice. Such progenitors may have potential to give rise to both basal squamous and columnar cells (as in BE), with the fate of its differentiated progeny determined by signals generated when repair is required. There may also be differences in progenitors based upon species. The normal human esophagus contains submucosal glands and ducts (ESMG/ESMD). Traditional rodent models are limited in that they lack the esophageal glands and ducts found in humans. As a consequence, these animals are not adequate for modeling the potential role of submucosal progenitor cells in the initiation of BE and EAC. Here I propose to develop a small animal model (guinea pig) to further our understanding of the role of submucosal progenitor cells in esophageal injury and repair, as well as a large animal (pig) based system of ESMG/ESMD isolation and culture. This project will serve as a training vehicle as well as a platform for my long term goal of studying these cells in the development of BE and EAC. In order to accomplish my long-term goal to improve early-detection of high-risk human esophageal disease and impact mortality associated with esophageal adenocarcinoma (EAC), I seek further career development in order to attain skills in epithelial biology, gastrointestinal stem cell biology, and animal models of esophageal injury and repair. Duke is a well-established research institution, with a clear commitment to supporting junior faculty development. I have already been provided independent laboratory space and 75% protected research time. I am fortunate to have a very strong mentoring team and research advisory committee to help facilitate my transition over the next few years to become an independent investigator with a strong skill-set in basic science techniques that will be developed through the proposed work. This project will be mentored by Dr. Anna Mae Diehl, an expert in cell biology and molecular pathways in gastrointestinal injury and repair, and it will be co-mentored by Dr. Susan Henning, an expert in intestinal stem cell biology. Experts in esophageal biology, animal models of esophageal disease, and epithelial repair will provide additional support and skills training. !
Esophageal injury by gastroesophageal reflux disease is quite common. For a subset of people with reflux, repeated esophageal injury eventually results in esophageal adenocarcinoma, a particularly deadly and devastating disease with a five-year survival of less than 17%. Our current screening and surveillance strategy for esophageal adenocarcinoma focuses on performing endoscopy in patients with reflux and other clinical risk factors (male sex, obesity), yet this strategy has failed to reduce the overall incidence of esophageal adenocarcinoma or improve survival. Most patients who are diagnosed with esophageal adenocarcinoma never had a preceding diagnosis of Barrett's esophagus, the metaplastic process associated with esophageal adenocarcinoma. The purpose of this research is to better understand the biology of esophageal injury and repair. Our long-term goal is to develop new models of esophageal injury, repair, and carcinogenesis that will eventually lead to better strategies for prevention of esophageal cancer new biomarker development to improve early detection of high-risk esophageal disease.