title: Isolation of stem-like cells from spontaneous feline mammary carcinomas: phenotypic characterization and tumorigenic potential.
abstract: Current carcinogenesis theory states that only a small subset of tumor cells, the cancer stem cells or tumor initiating cells (TICs), are responsible for tumor formation and progression. Human breast cancer-initiating cells have been identified as CD44-expressing cells, which retain tumorigenic activity and display stem cell-like properties. Spontaneous feline mammary carcinoma (FMC) is an aggressive cancer, which shows biological similarities to the human tumor counterpart. We report the isolation and phenotypic characterization of FMC-derived stem/progenitor cells, showing in vitro self-renewal, long-lasting proliferation and in vivo tumorigenicity. Twenty-one FMC samples were collected, histologically classified and characterized for the expression of Ki67, EGFR, ER-α and CD44, by immunohistochemistry. By culture in stem cell permissive conditions, we isolated, from 13 FMCs, a CD44-positive subpopulation able to survive and proliferate in vitro as mammospheres of different sizes and morphologies. When injected in NOD/SCID mice, FMC stem-like cells initiate tumors, generating cell heterogeneity and recapitulating the original histotype. In serum-containing medium, spheroid cells showed differentiation properties as shown by morphological changes, the loss of CD44 expression and tumorigenic potential. These data show that stem-defined culture of FMC enriches for TICs and validate the use of these cells as a suitable model for comparative oncology studies of mammary biology and testing therapeutic strategies aimed at eradicating TICs.
authors.affiliation: Section of Pharmacology, Dept. of Internal Medicine Di.M.I., and Center of Excellence for Biomedical Research - University of Genova, Viale Benedetto XV, 2, 16132 Genova, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Barbieri
authors.forename: Roberto
authors.initials: R
authors.lastname: Wurth
authors.forename: Alessandra
authors.initials: A
authors.lastname: Ratto
authors.forename: Chiara
authors.initials: C
authors.lastname: Campanella
authors.forename: Guendalina
authors.initials: G
authors.lastname: Vito
authors.forename: Stefano
authors.initials: S
authors.lastname: Thellung
authors.forename: Antonio
authors.initials: A
authors.lastname: Daga
authors.forename: Michele
authors.initials: M
authors.lastname: Cilli
authors.forename: Angelo
authors.initials: A
authors.lastname: Ferrari
authors.forename: Tullio
authors.initials: T
authors.lastname: Florio
mesh_terms: D000818:Animals; D002277:Carcinoma / Q000737:chemistry / Q000473:pathology*; D002415:Cats; D049109:Cell Proliferation; D002469:Cell Separation; D002478:Cells, Cultured; D004195:Disease Models, Animal; D066246:ErbB Receptors / Q000032:analysis; D047628:Estrogen Receptor alpha / Q000032:analysis; D005260:Female; D018960:Hyaluronan Receptors / Q000032:analysis; D019394:Ki-67 Antigen / Q000032:analysis; D015674:Mammary Neoplasms, Animal / Q000737:chemistry / Q000473:pathology*; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D060787:Neoplasm Grading; D014411:Neoplastic Stem Cells / Q000737:chemistry / Q000473:pathology*
chemical_list: D047628:Estrogen Receptor alpha; D018960:Hyaluronan Receptors; D019394:Ki-67 Antigen; D066246:ErbB Receptors