title: Regulation of mammary stem/progenitor cells by PTEN/Akt/beta-catenin signaling.
abstract: Recent evidence suggests that many malignancies, including breast cancer, are driven by a cellular subcomponent that displays stem cell-like properties. The protein phosphatase and tensin homolog (PTEN) is inactivated in a wide range of human cancers, an alteration that is associated with a poor prognosis. Because PTEN has been reported to play a role in the maintenance of embryonic and tissue-specific stem cells, we investigated the role of the PTEN/Akt pathway in the regulation of normal and malignant mammary stem/progenitor cell populations. We demonstrate that activation of this pathway, via PTEN knockdown, enriches for normal and malignant human mammary stem/progenitor cells in vitro and in vivo. Knockdown of PTEN in normal human mammary epithelial cells enriches for the stem/progenitor cell compartment, generating atypical hyperplastic lesions in humanized NOD/SCID mice. Akt-driven stem/progenitor cell enrichment is mediated by activation of the Wnt/beta-catenin pathway through the phosphorylation of GSK3-beta. In contrast to chemotherapy, the Akt inhibitor perifosine is able to target the tumorigenic cell population in breast tumor xenografts. These studies demonstrate an important role for the PTEN/PI3-K/Akt/beta-catenin pathway in the regulation of normal and malignant stem/progenitor cell populations and suggest that agents that inhibit this pathway are able to effectively target tumorigenic breast cancer cells.
authors.affiliation: Comprehensive Cancer Center, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA. hkorkaya@med.umich.edu
authors.forename: Hasan
authors.initials: H
authors.lastname: Korkaya
authors.forename: Amanda
authors.initials: A
authors.lastname: Paulson
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Charafe-Jauffret
authors.forename: Christophe
authors.initials: C
authors.lastname: Ginestier
authors.forename: Marty
authors.initials: M
authors.lastname: Brown
authors.forename: Julie
authors.initials: J
authors.lastname: Dutcher
authors.forename: Shawn G
authors.initials: SG
authors.lastname: Clouthier
authors.forename: Max S
authors.initials: MS
authors.lastname: Wicha
mesh_terms: D000818:Animals; D001940:Breast / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D001943:Breast Neoplasms / Q000473:pathology; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008321:Mammary Glands, Animal / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013234:Stem Cells / Q000378:metabolism* / Q000473:pathology; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism*
chemical_list: D051176:beta Catenin; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human