A new technique identifies regenerative cells
Even when an organ is believed to harbour stem cells, the cells themselves can be elusive. The standard method used to hunt for mammary stem cells involves injecting cells into the mammary fat pad of mice and seeing if the cells regenerate mammary tissue. Unfortunately, this approach is time consuming, highly variable and allows no way to count the cells. In this month's Nature Medicine, Connie Eaves and her team at the British Columbia Cancer Agency, Canada, report a new technique which has allowed them, for the first time, to characterize and quantify mammary gland stem cells in humans1.
This [work] could have important implications in our understanding of breast cancer.
ReferenceAnother link to the same article: Peter Eirew and 6 co-authors, including Joanne T Emerman and Connie J Eaves, Nat Med 2008(Dec); 14(12): 1384-9 [Epub 2008 Nov 23]. PubMed Abstract:
1. Eirew, P. et al. A method for quantifying normal human mammary epithelial stem cells with in vivo regenerative ability. Nature Med. advance online publication, doi:10.1038/nm.1791 (23 November 2008). | Article |
Previous studies have demonstrated that normal mouse mammary tissue contains a rare subset of mammary stem cells. We now describe a method for detecting an analogous subpopulation in normal human mammary tissue. Dissociated cells are suspended with fibroblasts in collagen gels, which are then implanted under the kidney capsule of hormone-treated immunodeficient mice. After 2-8 weeks, the gels contain bilayered mammary epithelial structures, including luminal and myoepithelial cells, their in vitro clonogenic progenitors and cells that produce similar structures in secondary transplants. The regenerated clonogenic progenitors provide an objective indicator of input mammary stem cell activity and allow the frequency and phenotype of these human mammary stem cells to be determined by limiting-dilution analysis. This new assay procedure sets the stage for investigations of mechanisms regulating normal human mammary stem cells (and possibly stem cells in other tissues) and their relationship to human cancer stem cell populations.[The commentary in Nature Reports Stem Cells is publicly accessible, but the article in Nature Medicine is not].