title: Mammosphere formation in breast carcinoma cell lines depends upon expression of E-cadherin.
abstract: Tumors are heterogeneous at the cellular level where the ability to maintain tumor growth resides in discrete cell populations. Floating sphere-forming assays are broadly used to test stem cell activity in tissues, tumors and cell lines. Spheroids are originated from a small population of cells with stem cell features able to grow in suspension culture and behaving as tumorigenic in mice. We tested the ability of eleven common breast cancer cell lines representing the major breast cancer subtypes to grow as mammospheres, measuring the ability to maintain cell viability upon serial non-adherent passage. Only MCF7, T47D, BT474, MDA-MB-436 and JIMT1 were successfully propagated as long-term mammosphere cultures, measured as the increase in the number of viable cells upon serial non-adherent passages. Other cell lines tested (SKBR3, MDA-MB-231, MDA-MB-468 and MDA-MB-435) formed cell clumps that can be disaggregated mechanically, but cell viability drops dramatically on their second passage. HCC1937 and HCC1569 cells formed typical mammospheres, although they could not be propagated as long-term mammosphere cultures. All the sphere forming lines but MDA-MB-436 express E-cadherin on their surface. Knock down of E-cadherin expression in MCF-7 cells abrogated its ability to grow as mammospheres, while re-expression of E-cadherin in SKBR3 cells allow them to form mammospheres. Therefore, the mammosphere assay is suitable to reveal stem like features in breast cancer cell lines that express E-cadherin.
authors.affiliation: Regulation of Cell Growth Laboratory, Fundacion Inbiomed, San Sebastián, Gipuzkoa, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Manuel Iglesias
authors.forename: Izaskun
authors.initials: I
authors.lastname: Beloqui
authors.forename: Francisco
authors.initials: F
authors.lastname: Garcia-Garcia
authors.forename: Olatz
authors.initials: O
authors.lastname: Leis
authors.forename: Alejandro
authors.initials: A
authors.lastname: Vazquez-Martin
authors.forename: Arrate
authors.initials: A
authors.lastname: Eguiara
authors.forename: Silvia
authors.initials: S
authors.lastname: Cufi
authors.forename: Andres
authors.initials: A
authors.lastname: Pavon
authors.forename: Javier A
authors.initials: JA
authors.lastname: Menendez
authors.forename: Joaquin
authors.initials: J
authors.lastname: Dopazo
authors.forename: Angel G
authors.initials: AG
authors.lastname: Martin
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D015820:Cadherins / Q000235:genetics*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D016000:Cluster Analysis; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D006801:Humans; D061986:MCF-7 Cells; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology; D018874:Spheroids, Cellular; D014407:Tumor Cells, Cultured
chemical_list: D015820:Cadherins