title: Earlier onset of syngeneic tumors in the presence of mesenchymal stem cells.
abstract: BACKGROUND
  Mesenchymal stem cells (MSC) are widely investigated for cell therapy purposes as support of hematopoietic cell transplantation, skeletal tissue regeneration, or as a cell delivery system of therapeutic agents in cancer. However, because of their immunosuppressive capacities, we investigated the effect of MSC on the development of syngeneic tumors.
  
  
  METHODS
  The murine MSC line C3H10T1/2 was coinjected with the Renca adenocarcinoma or the B16 melanoma cell lines in BALB/c mice.
  
  
  RESULTS
  The injection of MSC permitted the growth of the allogeneic B16 tumor cells and reduced the delay of tumor appearance when Renca cells were implanted, without modifying the kinetics of tumor growth. This effect was observed even with a low ratio of cancer cells, mimicking minimal residual disease. In this last case, no MSC were detected in the tumor mass, suggesting that cell contact was not necessary. The presence of MSC did not enhance the development of lung metastasis after systemic injection of Renca cells. Because the proliferative rate of Renca cells was not affected by in vitro coculture with MSC, this observation is likely due to a systemic suppressive effect on the host immune system.
  
  
  CONCLUSIONS
  Altogether, these data suggest that MSC did not interfere with the kinetics of tumor development but may reduce the delay for tumor occurrence. An important finding of this study is that a low but relevant amount of MSC may induce tumor rejection.
authors.affiliation: INSERM U475, Montpellier, France.
authors.forename: Farida
authors.initials: F
authors.lastname: Djouad
authors.forename: Claire
authors.initials: C
authors.lastname: Bony
authors.forename: Florence
authors.initials: F
authors.lastname: Apparailly
authors.forename: Pascale
authors.initials: P
authors.lastname: Louis-Plence
authors.forename: Christian
authors.initials: C
authors.lastname: Jorgensen
authors.forename: Danièle
authors.initials: D
authors.lastname: Noël
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D017690:Cell Transplantation / Q000379:methods*; D007165:Immunosuppression Therapy; D007700:Kinetics; D008175:Lung Neoplasms / Q000556:secondary; D008546:Melanoma, Experimental; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D009362:Neoplasm Metastasis; D009368:Neoplasm Transplantation; D009369:Neoplasms / Q000628:therapy*; D013234:Stem Cells / Q000166:cytology; D014185:Transplantation, Isogeneic