Identification of candidate murine esophageal stem cells using a combination of cell kinetic studies and cell surface markers

¹ Surgical Oncology Laboratory, Peter MacCallum Cancer Centre, St. Andrew's Place, East Melbourne, Victoria,, Australia
² Surgical Oncology Laboratory, Peter MacCallum Cancer Centre, St. Andrew's Place, East Melbourne, Victoria, Australia; University of Melbourne Department of Surgery, St. Vincent's Hospital Victoria Street, Fitzroy, Victoria, Australia
³ Epithelial Stem Cell Biology Laboratory, Peter MacCallum Cancer Centre, St. Andrew's Place, East Melbourne, Victoria, Australia

^* To whom correspondence should be addressed. E-mail: wayne.phillips{at}petermac,org.

	Abstract

The identification and characterization of esophageal stem cells is critical to our understanding of the biology of the esophageal epithelium in health and disease. However the proliferative compartment within the mouse esophageal epithelium remains poorly characterized. Here we report that the basal cells of the mouse esophagus can be separated into three phenotypically and functionally distinct subpopulations based on the expression of ₆ integrin and transferrin receptor (CD71). Cells that express high levels of ₆ integrin and low levels of CD71, termed ₆^briCD71^dim, are a minor subpopulation of small and undifferentiated cells that are enriched for label-retaining cells and thus represent a putative esophageal stem cell population. Conversely, cells expressing high levels of both ₆ integrin and CD71 (₆^briCD71^bri), the majority of basal esophageal cells, are enriched for actively cycling cells and therefore represent a transit amplifying population. Kinetic analyses revealed that a third cell population, which is ₆ integrin dim and CD71 bright (₆^dim), is destined to leave the basal layer and differentiate.