title: Divalent cations modulate alpha2beta1 integrin-mediated malignancy in a novel 3-dimensional in vitro model of pancreatic cancer.
abstract: OBJECTIVE
  We previously showed that divalent cations regulate alpha2beta1 integrin-mediated pancreatic cancer cell interactions with type I collagen in 2 dimensions (2D), including cell adhesion, migration, and proliferation. Presently, we examined divalent cation-dependent alpha2beta1 integrin-mediated pancreatic cancer cell adhesion and proliferation on type I collagen in a novel 3D in vitro model.
  
  
  METHODS
  Cell attachment, proliferation, and antibody inhibition assays on type I collagen in both 2D and 3D, and microscopy and immunoblotting were used for these studies.
  
  
  RESULTS
  As in 2D, cell attachment on type I collagen in 3D is Mg-dependent and inhibited by Ca. Proliferation in 3D is also Mg-dependent, but maximal when Mg is present at concentrations that promote maximal cell adhesion and Ca is present at concentrations less than Mg. Immunoblotting studies demonstrate that the divalent cation-dependent changes in cell-cell adhesion observed on type I collagen in both 2D and 3D are associated with the changes in E-cadherin and beta-catenin expression. Antibody inhibition assays indicate further that the alpha2beta1 integrin specifically mediates proliferation on type I collagen in 3D under altered divalent cation conditions.
  
  
  CONCLUSIONS
  Divalent cation shifts could activate alpha2beta1 integrin-mediated malignancy in the type I collagen-rich 3D tumor microenvironment of pancreatic cancer.
authors.affiliation: From the Department of Surgery, VA San Diego Healthcare System and the University of California, San Diego, San Diego, CA 92161, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Grzesiak
authors.forename: Fabian
authors.initials: F
authors.lastname: Vargas
authors.forename: Michael
authors.initials: M
authors.lastname: Bouvet
mesh_terms: D015820:Cadherins / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology*; D002413:Cations, Divalent / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D018929:Cell Culture Techniques / Q000379:methods; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D024042:Collagen Type I / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D015151:Immunoblotting; D038982:Integrin alpha2beta1 / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology*; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology; D051176:beta Catenin / Q000378:metabolism
chemical_list: D015820:Cadherins; D002413:Cations, Divalent; D024042:Collagen Type I; D038982:Integrin alpha2beta1; D051176:beta Catenin; D008274:Magnesium; D002118:Calcium