title: Evaluation of stem cell properties in human ovarian carcinoma cells using multi and single cell-based spheres assays.
abstract: Years of research indicates that ovarian cancers harbor a heterogeneous mixture of cells including a subpopulation of so-called "cancer stem cells" (CSCs) responsible for tumor initiation, maintenance and relapse following conventional chemotherapies. Identification of ovarian CSCs is therefore an important goal. A commonly used method to assess CSC potential in vitro is the spheres assay in which cells are plated under non-adherent culture conditions in serum-free medium supplemented with growth factors and sphere formation is scored after a few days. Here, we review currently available protocols for human ovarian cancer spheres assays and perform a side-by-side analysis between commonly used multi cell-based assays and a more accurate system based on single cell plating. Our results indicate that both multi cell-based as well as single cell-based spheres assays can be used to investigate sphere formation in vitro. The more laborious and expensive single cell-based assays are more suitable for functional assessment of individual cells and lead to overall more accurate results while multi cell-based assays can be strongly influenced by the density of plated cells and require titration experiments upfront. Methylcellulose supplementation to multi cell-based assays can be effectively used to reduce mechanical artifacts.
authors.affiliation: Department of Biomedicine, University Hospital Basel; Department of Internal Medicine II, University Hospital Tübingen.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Biomedicine, University Hospital Basel.
authors.forename: Anna
authors.initials: A
authors.lastname: Paczulla
authors.affiliation: Department of Biomedicine, University Hospital Basel; Department of Internal Medicine II, University Hospital Tübingen; claudia.lengerke@unibas.ch.
authors.forename: Claudia
authors.initials: C
authors.lastname: Lengerke
mesh_terms: D002452:Cell Count; D018929:Cell Culture Techniques / Q000379:methods*; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D014411:Neoplastic Stem Cells / Q000473:pathology*; D010051:Ovarian Neoplasms / Q000473:pathology*; D018874:Spheroids, Cellular / Q000473:pathology