Lgr6 labels a rare population of mammary gland progenitor cells that are able to originate luminal mammary tumours Leander Blaas Fabio Pucci Hendrik A Messal Agneta B Andersson E Josue Ruiz Marco Gerling Iyadh Douagi Bradley Spencer-Dene Alexandra Musch Richard Mitter Leena Bhaw Richard Stone Dorothee Bornhorst Abdul K Sesay Jos Jonkers Gordon Stamp Ilaria Malanchi Rune Toftgård Axel Behrens 10779/crick.12595148.v1 https://crick.figshare.com/articles/journal_contribution/Lgr6_labels_a_rare_population_of_mammary_gland_progenitor_cells_that_are_able_to_originate_luminal_mammary_tumours/12595148 The mammary gland is composed of a complex cellular hierarchy with unusual postnatal plasticity. The identities of stem/progenitor cell populations, as well as tumour-initiating cells that give rise to breast cancer, are incompletely understood. Here we show that Lgr6 marks rare populations of cells in both basal and luminal mammary gland compartments in mice. Lineage tracing analysis showed that Lgr6+ cells are unipotent progenitors, which expand clonally during puberty but diminish in adulthood. In pregnancy or following stimulation with ovarian hormones, adult Lgr6+ cells regained proliferative potency and their progeny formed alveoli over repeated pregnancies. Oncogenic mutations in Lgr6+ cells resulted in expansion of luminal cells, culminating in mammary gland tumours. Conversely, depletion of Lgr6+ cells in the MMTV-PyMT model of mammary tumorigenesis significantly impaired tumour growth. Thus, Lgr6 marks mammary gland progenitor cells that can initiate tumours, and cells of luminal breast tumours required for efficient tumour maintenance. 2020-07-01 17:09:49 Alleles Animals Animals, Newborn Breast Neoplasms Carcinogenesis Cell Lineage Cell Proliferation Clone Cells Disease-Free Survival Drug Resistance, Neoplasm Female Gene Expression Regulation, Neoplastic Homeostasis Hormones Humans Mammary Glands, Animal Mammary Neoplasms, Experimental Mice Neoplastic Stem Cells Pregnancy Receptors, G-Protein-Coupled Stem Cells Up-Regulation Behrens FC001039 Malanchi FC001112 HP CB AS Developmental Biology 06 Biological Sciences 11 Medical and Health Sciences