Characterization of Human Mammary Epithelial Stem Cells
Abstract
The mammary epithelium of normal adult female mice contains stem cells with extensive in vivo regenerative and self-renewal potential. Analogous cells presumably exist in the mammary glands of adult women, and are candidate targets for the first transforming mutations that lead to the evolution of breast cancer stem cells. The objective of this grant is to develop a robust, quantitative and specific assay for these hypothesized normal human mammary stem cells, to enable identification of markers of these stem cells, to develop a method for their purification, and to derive information about their frequency and how they are regulated. In the first 2 years of this grant, we have established conditions that allow human mammary gland structures to be reproducibly generated in subrenal xenografts in highly immunodeficient mice, starting with small innocula of dissociated human mammary cells. The regenerated glands are similar in morphology and cellular organization to normal human mammary glands, bounded by a basement membrane with an outer layer of myo-epithelial cells and an inner layer of polarized luminal cells that can be induced to produce milk. We have also established that the presence of regenerated structures can be determined by detecting the in vitro clonogenic progenitors they contain and this endpoint can serve as an objective indicator of the presence of a primitive stem-like cell in the initial cells transplanted. This retrospective functional assay allows limiting dilution analysis of positive xenograft yields to derive stem cell frequencies in differently manipulated populations. Using this approach we have found the frequency of stem cells in normal human mammary tissue to be ~1 per 5000 cells and their phenotype to be CD49f+ EpCAM-/low CD31-CD45-. These findings set the stage for further biological and molecular characterization studies of normal human mammary stem cells and their relationship to human breast cancer stem cells.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2008
- Accession Number
- ADA501896
Entities
People
- Peter D. Eirew
Organizations
- BC Cancer Agency