title: Effects of low confluency, serum starvation and hypoxia on the side population of cancer cell lines.
abstract: The cancer stem cell theory describes a small subset of cancer cells that have the ability to initiate and drive the growth of a tumor. The niche refers to the environmental factors and the surrounding cells within which the tumor develops. The exact relationship between cancer stem cells and the tumor niche is not known. However, using side population analysis by flow cytometry, it is possible to analyze the relationship between environmental stresses and putative cancer stem cells. The side population is a subpopulation of cells that efflux Hoechst 33342 and has been previously shown to be enriched for cancer stem cells. Using this technique, we characterized the response of side population cells to low confluency, serum starvation and hypoxia using three different human cancer cell lines. We found that these stresses, characteristic of the tumor niche enrich the side population of DLD1, SW480 and MCF7 cancer cell lines, thus possibly predisposing the tumor to a more malignant phenotype.
authors.affiliation: Laboratory of Molecular Oncology and Cell Cycle Regulation, Department of Medicine (Hematology/Oncology), The Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Raluca T
authors.initials: RT
authors.lastname: Tavaluc
authors.forename: Lori S
authors.initials: LS
authors.lastname: Hart
authors.forename: David T
authors.initials: DT
authors.lastname: Dicker
authors.forename: Wafik S
authors.initials: WS
authors.lastname: El-Deiry
mesh_terms: D018929:Cell Culture Techniques / Q000379:methods*; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006801:Humans; D009369:Neoplasms / Q000473:pathology*; D044967:Serum