title: Stroma regulates increased epithelial lateral cell adhesion in 3D culture: a role for actin/cadherin dynamics.
abstract: BACKGROUND
  Cell shape and tissue architecture are controlled by changes to junctional proteins and the cytoskeleton. How tissues control the dynamics of adhesion and cytoskeletal tension is unclear. We have studied epithelial tissue architecture using 3D culture models and found that adult primary prostate epithelial cells grow into hollow acinus-like spheroids. Importantly, when co-cultured with stroma the epithelia show increased lateral cell adhesions. To investigate this mechanism further we aimed to: identify a cell line model to allow repeatable and robust experiments; determine whether or not epithelial adhesion molecules were affected by stromal culture; and determine which stromal signalling molecules may influence cell adhesion in 3D epithelial cell cultures.
  
  
  RESULTS
  The prostate cell line, BPH-1, showed increased lateral cell adhesion in response to stroma, when grown as 3D spheroids. Electron microscopy showed that 9.4% of lateral membranes were within 20 nm of each other and that this increased to 54% in the presence of stroma, after 7 days in culture. Stromal signalling did not influence E-cadherin or desmosome RNA or protein expression, but increased E-cadherin/actin co-localisation on the basolateral membranes, and decreased paracellular permeability. Microarray analysis identified several growth factors and pathways that were differentially expressed in stroma in response to 3D epithelial culture. The upregulated growth factors TGFβ2, CXCL12 and FGF10 were selected for further analysis because of previous associations with morphology. Small molecule inhibition of TGFβ2 signalling but not of CXCL12 and FGF10 signalling led to a decrease in actin and E-cadherin co-localisation and increased paracellular permeability.
  
  
  CONCLUSIONS
  In 3D culture models, paracrine stromal signals increase epithelial cell adhesion via adhesion/cytoskeleton interactions and TGFβ2-dependent mechanisms may play a key role. These findings indicate a role for stroma in maintaining adult epithelial tissue morphology and integrity.
authors.affiliation: YCR Cancer Research Unit, Department of Biology, University of York, Heslington, York, United Kingdom.
authors.forename: Karen F
authors.initials: KF
authors.lastname: Chambers
authors.forename: Joanna F
authors.initials: JF
authors.lastname: Pearson
authors.forename: Naveed
authors.initials: N
authors.lastname: Aziz
authors.forename: Peter
authors.initials: P
authors.lastname: O'Toole
authors.forename: David
authors.initials: D
authors.lastname: Garrod
authors.forename: Shona H
authors.initials: SH
authors.lastname: Lang
mesh_terms: D000199:Actins / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism*; D002448:Cell Adhesion; D002460:Cell Line; D054377:Chemokine CXCL12 / Q000378:metabolism; D018920:Coculture Techniques; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D051526:Fibroblast Growth Factor 10 / Q000378:metabolism; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D011467:Prostate / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D015398:Signal Transduction; D017154:Stromal Cells / Q000166:cytology* / Q000378:metabolism; D053781:Transforming Growth Factor beta2 / Q000378:metabolism
chemical_list: D000199:Actins; C515255:CXCL12 protein, human; D015820:Cadherins; D054377:Chemokine CXCL12; C496463:FGF10 protein, human; D051526:Fibroblast Growth Factor 10; C509041:TGFB2 protein, human; D053781:Transforming Growth Factor beta2