title: Intercellular adhesion can be visualized using fluorescently labeled fibrosarcoma HT1080 cells cocultured with hematopoietic cell lines or CD34(+) enriched human mobilized peripheral blood cells.
abstract: BACKGROUND
  Intercellular contacts between adjacent cells migrating over each other are important in many cellular processes. However, it has been difficult to visualize and identify dynamic intercellular adhesions between migrating cells in situ.
  
  
  METHODS
  Two fluorescent membrane dyes, PKH2 and PKH26 for staining HT1080 and hematopoietic cells and cell lines, and an automated fluorescence microscopy system were used to monitor intercellular adhesion.
  
  
  RESULTS
  Cellular extensions connecting two or more adjacent cells were visualized, showing the intercellular adhesion between migrating cells for minutes and up to hours. After cells adhered to each other, followed by cell migration in different directions, cellular extensions were dragged from the pivotal contact points in different focal planes. CD34(+)-enriched mobilized peripheral blood cells and six hematopoietic cell lines showed intercellular connections in cocultures with HT1080. However, the frequency of intercellular connections was variable in different cocultures. A cell density of about 3.1 x 10(4) cells/cm(2) for both cell lines in cocultures provided an adequate number of cells in each field of view, showing up to four intercellular connections per 100 total cells plated.
  
  
  CONCLUSIONS
  The tools derived from this study will open new areas of investigation for understanding the mechanism of the intercellular adhesion process.
authors.affiliation: Department of Bioengineering, University of California at San Diego, 92093-0412, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Oh
authors.forename: A R
authors.initials: AR
authors.lastname: Martinez
authors.forename: G M
authors.initials: GM
authors.lastname: Lee
authors.forename: K
authors.initials: K
authors.lastname: Francis
authors.forename: B O
authors.initials: BO
authors.lastname: Palsson
mesh_terms: D018952:Antigens, CD34 / Q000032:analysis*; D002051:Burkitt Lymphoma; D002448:Cell Adhesion / Q000502:physiology; D002452:Cell Count; D018929:Cell Culture Techniques / Q000379:methods; D005354:Fibrosarcoma; D005456:Fluorescent Dyes; D006412:Hematopoietic Stem Cells / Q000737:chemistry* / Q000166:cytology*; D006801:Humans; D015448:Leukemia, B-Cell; D015470:Leukemia, Myeloid, Acute; D015458:Leukemia, T-Cell; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods; D009930:Organic Chemicals; D014407:Tumor Cells, Cultured / Q000737:chemistry / Q000166:cytology
chemical_list: D018952:Antigens, CD34; D005456:Fluorescent Dyes; D009930:Organic Chemicals; C070080:PKH 26; C067882:PKH2-GL