title: A paper-based invasion assay: assessing chemotaxis of cancer cells in gradients of oxygen.
abstract: This work describes a 3D, paper-based assay that can isolate sub-populations of cells based on their invasiveness (i.e., distance migrated in a hydrogel) in a gradient of concentration of oxygen (O2). Layers of paper impregnated with a cell-compatible hydrogel are stacked and placed in a plastic holder to form the invasion assay. In most assays, the stack comprises a single layer of paper containing mammalian cells suspended in a hydrogel, sandwiched between multiple layers of paper containing only hydrogel. Cells in the stack consume and produce small molecules; these molecules diffuse throughout the stack to generate gradients in the stack, and between the stack and the bulk culture medium. Placing the cell-containing layer in different positions of the stack, or modifying the permeability of the holder to oxygen or proteins, alters the profile of the gradients within the stack. Physically separating the layers after culture isolates sub-populations of cells that migrated different distances, and enables their subsequent analysis or culture. Using this system, three independent cell lines derived from A549 cancer cells are shown to produce distinguishable migration behavior in a gradient of oxygen. This result is the first experimental demonstration that oxygen acts as a chemoattractant for cancer cells.
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA; Wyss Institute of Biologically Inspired Engineering, Harvard University, 60 Oxford Street, Cambridge, MA 02138, USA. Electronic address: bom2008@cornell.med.edu.
authors.forename: Bobak
authors.initials: B
authors.lastname: Mosadegh
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Lockett
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
authors.forename: Kyaw Thu
authors.initials: KT
authors.lastname: Minn
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
authors.forename: Karen A
authors.initials: KA
authors.lastname: Simon
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
authors.forename: Karl
authors.initials: K
authors.lastname: Gilbert
authors.affiliation: Vertex Pharmaceuticals Incorporated, 50 Northern Avenue, Boston, MA 02210, USA.
authors.forename: Shawn
authors.initials: S
authors.lastname: Hillier
authors.affiliation: Vertex Pharmaceuticals Incorporated, 50 Northern Avenue, Boston, MA 02210, USA.
authors.forename: David
authors.initials: D
authors.lastname: Newsome
authors.affiliation: Vertex Pharmaceuticals Incorporated, 50 Northern Avenue, Boston, MA 02210, USA.
authors.forename: Howard
authors.initials: H
authors.lastname: Li
authors.affiliation: Vertex Pharmaceuticals Incorporated, 50 Northern Avenue, Boston, MA 02210, USA.
authors.forename: Amy B
authors.initials: AB
authors.lastname: Hall
authors.affiliation: Vertex Pharmaceuticals Incorporated, 50 Northern Avenue, Boston, MA 02210, USA.
authors.forename: Diane M
authors.initials: DM
authors.lastname: Boucher
authors.affiliation: Vertex Pharmaceuticals Incorporated, 50 Northern Avenue, Boston, MA 02210, USA. Electronic address: brenda_eustace@vrtx.com.
authors.forename: Brenda K
authors.initials: BK
authors.lastname: Eustace
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA; Wyss Institute of Biologically Inspired Engineering, Harvard University, 60 Oxford Street, Cambridge, MA 02138, USA. Electronic address: gwhitesides@gmwgroup.harvard.edu.
authors.forename: George M
authors.initials: GM
authors.lastname: Whitesides
mesh_terms: D000818:Animals; D001681:Biological Assay; D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D002470:Cell Survival; D002630:Chemotactic Factors / Q000737:chemistry; D002633:Chemotaxis; D057809:HEK293 Cells; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008962:Models, Theoretical; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000473:pathology*; D010100:Oxygen / Q000737:chemistry*; D010209:Paper; D010539:Permeability; D010641:Phenotype
chemical_list: D002630:Chemotactic Factors; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D010100:Oxygen
keywords: Cancer; Chemotaxis; Invasion assay; Migration; Oxygen gradients