title: Juxtacrine stimulation of normal and malignant human bladder epithelial cell proliferation.
abstract: OBJECTIVE
  We developed a method for culturing normal and malignant human bladder epithelial cells for many generations.
  
  
  METHODS
  Cells from bladder washes or surgical specimens were plated in culture with lethally irradiated cells of the LA7 rat mammary tumor line (American Type Culture Collection, Bethesda, Maryland) at a confluent density and fed regularly. After cells from surgical specimens became confluent they were diluted and subcultured with fresh irradiated LA7 cells. The growth rate was measured by cell counts and cell sorter analysis. Expression of intermediate filaments was determined by immunocytochemical testing.
  
  
  RESULTS
  All 5 normal and 3 of the 4 tumor specimens developed into long-term cell strains. A single normal strain was carried through passage 11, amounting to 37 cell doublings. Cell numbers doubled in 2 days in medium with 0.5% serum and in 5.6 days in 5% serum. Plating efficiency was almost 100% and cloning efficiency was approximately 9%. LA7 conditioned medium did not stimulate bladder cell proliferation. Two tumor strains were carried through passage 9, amounting to 20 and 27 doublings, respectively. No cell strains expressed signs of senescence at culture termination. Normal and tumor strains expressed keratins 7, 10, 11, 18 and 19, and ZO1 tight junction protein but not vimentin or keratin 14. Umbrella cells comprised the uppermost cell layer in cultures from normal bladder.
  
  
  CONCLUSIONS
  LA7 feeder cells stimulate human bladder cell proliferation for many generations in culture by a juxtacrine mechanism and promote the expression of differentiated traits.
authors.affiliation: Department of Pathology and Laboratory Services and Section of Urology, Veterans Affairs Palo Alto Health Care System and Department of Urology, Stanford University Medical Center, Stanford, California.
authors.forename: Ursula K
authors.initials: UK
authors.lastname: Ehmann
authors.forename: Martha K
authors.initials: MK
authors.lastname: Terris
mesh_terms: D000818:Animals; D002295:Carcinoma, Transitional Cell / Q000473:pathology*; D018929:Cell Culture Techniques; D002455:Cell Division; D002478:Cells, Cultured; D018920:Coculture Techniques; D017077:Culture Media, Conditioned; D004847:Epithelial Cells / Q000648:ultrastructure; D017629:Gap Junctions; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000276:immunology; D008321:Mammary Glands, Animal / Q000166:cytology; D051381:Rats; D019108:Tight Junctions / Q000502:physiology; D014407:Tumor Cells, Cultured; D001743:Urinary Bladder / Q000166:cytology*; D001749:Urinary Bladder Neoplasms / Q000473:pathology*
chemical_list: D017077:Culture Media, Conditioned; D007633:Keratins