title: A high-content assay to identify small-molecule modulators of a cancer stem cell population in luminal breast cancer.
abstract: Breast cancers expressing hormone receptors for estrogen (ER) and progesterone (PR) represent ~70% of all cases and are treated with both ER-targeted and chemotherapies, with near 40% becoming resistant. We have previously described that in some ER(+) tumors, the resistant cells express cytokeratin 5 (CK5), a putative marker of breast stem and progenitor cells. CK5(+) cells have lost expression of ER and PR, express the tumor-initiating cell surface marker CD44, and are relatively quiescent. In addition, progestins, which increase breast cancer incidence, expand the CK5(+) subpopulation in ER(+)PR(+) breast cancer cell lines. We have developed models to induce and quantitate CK5(+)ER(-)PR(-) cells, using CK5 promoter-driven luciferase (Fluc) or green fluorescent protein (GFP) reporters stably transduced into T47D breast cancer cells (CK5Pro-GFP or CK5Pro-Luc). We validated the CK5Pro-GFP-T47D model for high-content screening in 96-well microplates and performed a pilot screen using a focused library of 280 compounds from the National Institutes of Health clinical collection. Four hits were obtained that significantly abrogated the progestin-induced CK5(+) cell population, three of which were members of the retinoid family. Hence, this approach will be useful in discovering small molecules that could potentially be developed as combination therapies, preventing the acquisition of a drug-resistant subpopulation.
authors: Department of Pharmaceutical Sciences, The Skaggs School of Pharmacy, The University of Colorado, Aurora, CO 80045, USA.
authors: Byong Hoon
authors: BH
authors: Yoo
authors: Sunshine Daddario
authors: SD
authors: Axlund
authors: Peter
authors: P
authors: Kabos
authors: Brian G
authors: BG
authors: Reid
authors: Jerome
authors: J
authors: Schaack
authors: Carol A
authors: CA
authors: Sartorius
authors: Daniel V
authors: DV
authors: LaBarbera
mesh_terms: D017255:Acitretin / Q000494:pharmacology; D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D055808:Drug Discovery / Q000379:methods*; D019008:Drug Resistance, Neoplasm; D005260:Female; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D015474:Isotretinoin / Q000494:pharmacology; D053555:Keratin-5 / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008825:Miconazole / Q000494:pharmacology; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000378:metabolism; D011374:Progesterone / Q000494:pharmacology; D011372:Progestins / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012176:Retinoids / Q000494:pharmacology*; D054852:Small Molecule Libraries / Q000494:pharmacology*; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D018931:Antineoplastic Agents, Hormonal; C497483:CD44 protein, human; D018960:Hyaluronan Receptors; D053555:Keratin-5; D011372:Progestins; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D012176:Retinoids; D054852:Small Molecule Libraries; D049452:Green Fluorescent Proteins; D011374:Progesterone; D014212:Tretinoin; D008825:Miconazole; D008156:Luciferases; D015474:Isotretinoin; D017255:Acitretin