title: Simulating tumor microenvironment: changes in protein expression in an in vitro co-culture system.
abstract: BACKGROUND
  The role of the microenvironment during the initiation and progression of carcinogenesis is thought to be of critical importance, both for the enhanced understanding of fundamental cancer biology as well as for improving molecular diagnostics and therapeutics. The aim of this study was to establish an in vitro model based on a co-culture of healthy human fibroblasts (HFs) and human osteosarcoma cells (MG-63s) to simulate the microenvironment including tumor and healthy cells.
  
  
  METHODS
  The HFs and MG-63s were in vitro co-cultured for a period of time ranging from 24 h to 7 days. Cell morphology and organization were studied using phase contrast microscopy while the expression of Human Cartilage Glycoprotein 39 (YKL-40), Vascular Endothelial Growth Factor (VEGF) and Matrix Metalloprotease 1 (MMP1) was investigated by Real Time PCR and Western Blotting.
  
  
  RESULTS
  The results showed a characteristic disposition of tumor and healthy co-cultured cells in columns which are not visible in tumor and healthy cells grown singularly. The expression of YKL-40, VEGF and MMP1 significantly changed in co-cultured cells compared to HFs and MG-63s separately cultured.
  
  
  CONCLUSIONS
  We concluded that the tumor microenvironment has an influence on the protein expression of the healthy surrounding tissues and the process of tumorigenicity.
authors.affiliation: Department for Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, via Irnerio 48, Bologna 40126, Italy.
authors.forename: Viviana
authors.initials: V
authors.lastname: Salvatore
authors.affiliation: Department for Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, via Irnerio 48, Bologna 40126, Italy.
authors.forename: Gabriella
authors.initials: G
authors.lastname: Teti
authors.affiliation: Department for Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, via Irnerio 48, Bologna 40126, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Bolzani
authors.affiliation: Department for Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, via Irnerio 48, Bologna 40126, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Focaroli
authors.affiliation: Department for Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, via Irnerio 48, Bologna 40126, Italy.
authors.forename: Sandra
authors.initials: S
authors.lastname: Durante
authors.affiliation: Department for Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, via Irnerio 48, Bologna 40126, Italy.
authors.forename: Maria Carla
authors.initials: MC
authors.lastname: Mazzotti
authors.affiliation: Department for Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, via Irnerio 48, Bologna 40126, Italy.
authors.forename: Mirella
authors.initials: M
authors.lastname: Falconi
keywords: Cell-cell contacts; Co-cultures; Human fibroblast cells; MMP1; Osteosarcoma cell line; Tumor microenvironment; VEGF; YKL-40