Data from Hedgehog Signaling and Bmi-1 Regulate Self-renewal of Normal and Malignant Human Mammary Stem Cells

Autor: Max S. Wicha, Prerna Suri, Kyle W. Jackson, Nam-shik Ahn, Shivani Patel, Ilia D. Mantle, Gabriela Dontu, Suling Liu
Rok vydání: 2023
DOI: 10.1158/0008-5472.c.6494715
Popis: The epithelial components of the mammary gland are thought to arise from stem cells with a capacity for self-renewal and multilineage differentiation. Furthermore, these cells and/or their immediate progeny may be targets for transformation. We have used both in vitro cultivation and a xenograft mouse model to examine the role of hedgehog signaling and Bmi-1 in regulating self-renewal of normal and malignant human mammary stem cells. We show that hedgehog signaling components PTCH1, Gli1, and Gli2 are highly expressed in normal human mammary stem/progenitor cells cultured as mammospheres and that these genes are down-regulated when cells are induced to differentiate. Activation of hedgehog signaling increases mammosphere-initiating cell number and mammosphere size, whereas inhibition of the pathway results in a reduction of these effects. These effects are mediated by the polycomb gene Bmi-1. Overexpression of Gli2 in mammosphere-initiating cells results in the production of ductal hyperplasia, and modulation of Bmi-1 expression in mammosphere-initiating cells alters mammary development in a humanized nonobese diabetic-severe combined immunodeficient mouse model. Furthermore, we show that the hedgehog signaling pathway is activated in human breast “cancer stem cells” characterized as CD44+CD24−/lowLin−. These studies support a cancer stem cell model in which the hedgehog pathway and Bmi-1 play important roles in regulating self-renewal of normal and tumorigenic human mammary stem cells. (Cancer Res 2006; 66(12): 6063-71)
Databáze: OpenAIRE