Role of the Stem Cell Niche in Hormone-Induced Tumorigenesis in Fetal Mouse Mammary Epithelium
Final rept. 15 Jul 2004-14 Jul 2005
GEORGETOWN UNIV WASHINGTON DC
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Stem cells possess properties that compel the tissue to devise some method to contain and husband them. They are mobile, environmentally highly responsive, self renewing and pluripotent. A structure specialized to contain and regulate stem cell activity has been structurally and molecularly described in Drosophila and some mammalian tissues. The structure, the stem cell niche, functions to 1 shield the stem cell from the burden of incoming hormone and growth factor signals present in the surrounding tissue, 2 supply, interpret, and regulate specific signals to modulate tissue growth by directing stem cell renewal and maturation, 3 prevent stem cells from wandering through the tissue and producing new cells inappropriately, 4 prevent stem cells from leaving the tissue inappropriately and potentially colonizing other tissues. Because of it potential in preventing tumorigenesis we turned our attention to it description in situ in mouse mammary epithelium. We are developing immunostaining staining protocols for molecules shown to be involved in niche signaling in drosophila and mammalian gut and have been successful with P63, Notch-i and Oct-4. Our results to date suggest that the stem cell niche in the mammary gland may exist in an extended hierarchy or layered structures rather than the simple organization seen in drosophila gonads.
- Anatomy and Physiology