Is the Regenerative Capacity of the Mammary Gland Contained With Those Mammary Cells That Express the Progesterone Receptor. Implications for Breast Cancer

摘要

We hypothesized that mammary-specific stem cells are present as a subgroup within those epithelial cells that express the progesterone receptor (PR) . To determine whether a stem cell population is contained within the PR expressing cell population (PR+), a recently generated (yet to be published) PR- lacZ knockin mouse in combination with fluorescent- activated cell sorting (PACS) was utilized to separate PR+ from PR- mammary cells; both cell populations would then be evaluated for their regenerative capacity by transplantation into the cleared mammary fat pad of a host animal. As previously described in our final report, PACS analysis applied to the PR-lacZ mammary gland provided a significantly enriched ((caret)70%) PR+ mammary epithelial cell population that maintained lacz expression in culture. Although, PR+ and PR- enriched mammary epithelial cell populations were transplanted into mammary fat pads, these host animals as well as much of the PR-lacZ colony were lost to Tropical Storm 'Allison'. To estimate the regenerative potential of the above mammary epithelial cell population, a 6-month no cost extension was requested. Unfortunately, due to severity of the loss of the PR-lacz mouse colony, this extension was not sufficient to allow recovery and rederivation of the PR-lacz colony.