title: Therapy with Multipotent Mesenchymal Stromal Cells Protects Lungs from Radiation-Induced Injury and Reduces the Risk of Lung Metastasis.
abstract: OBJECTIVE
  Previous thorax irradiation promotes metastatic spread of tumor cells to the lung. We hypothesized that vascular damage facilitates lung metastasis after thorax irradiation and that therapeutically applied multipotent mesenchymal stromal cells (MSCs) with reported repair activity may prevent these adverse effects of ionizing radiation by protecting lung endothelia from radiation-induced damage.
  
  
  RESULTS
  Previous whole-thorax irradiation (WTI) with 15 Gy significantly enhanced seeding and metastatic growth of tumor cells in the lung. WTI was further associated with endothelial cell damage, senescence of lung epithelial cells, and upregulation of invasion- and inflammation-promoting soluble factors, for example, endothelial matrix metalloproteinase 2 (Mmp2), its activator Mmp14, the cofactor tissue inhibitor of metalloproteinases 2 (Timp2), chemokine (C-C motif) ligand 2 (Ccl2), and urokinase-type plasminogen activator (Plau/uPA), and recruitment of CD11b+CD11c- myelomonocytic cells. Inhibition of Mmp2 counteracted radiation-induced vascular dysfunction without preventing increased metastasis. In contrast, therapy with bone marrow or aorta-derived MSCs within 2 weeks postirradiation antagonized radiation-induced damage to resident cells as well as the resulting secretome changes and abrogated the metastasis-promoting effects of WTI.
  
  
  METHODS
  Therapy with MSCs protects lungs from radiation-induced injury and reduces the risk of lung metastasis. MSC-mediated inhibition of Mmp2 mediates their protective effects at the vasculature. Furthermore, local and systemic effects such as inhibition of radiation-induced senescence of bronchial epithelial cells and associated secretion of immunomodulatory factors may participate in the inhibitory effect of MSCs on lung metastasis.
  
  
  CONCLUSIONS
  MSC therapy is a promising strategy to prevent radiation-induced lung injury and the resulting increased risk of metastasis.
authors.affiliation: 1 Institute of Cell Biology (Cancer Research), University Hospital, University of Duisburg-Essen , Essen, Germany .
authors.forename: Diana
authors.initials: D
authors.lastname: Klein
authors.affiliation: 1 Institute of Cell Biology (Cancer Research), University Hospital, University of Duisburg-Essen , Essen, Germany .
authors.forename: Alexandra
authors.initials: A
authors.lastname: Schmetter
authors.affiliation: 1 Institute of Cell Biology (Cancer Research), University Hospital, University of Duisburg-Essen , Essen, Germany .
authors.forename: Roze
authors.initials: R
authors.lastname: Imsak
authors.affiliation: 1 Institute of Cell Biology (Cancer Research), University Hospital, University of Duisburg-Essen , Essen, Germany .
authors.forename: Florian
authors.initials: F
authors.lastname: Wirsdörfer
authors.affiliation: 2 Research Unit Radiation Cytogenetics, Helmholtz-Zentrum München, German Research Center for Environmental Health , Neuherberg, Germany and Clinical Cooperation Group 'Personalized Radiotherapy in Head and Neck Cancer', Helmholtz-Zentrum München, Neuherberg, Germany .
authors.forename: Kristian
authors.initials: K
authors.lastname: Unger
authors.affiliation: 3 Institute of Anatomy, University Hospital, University of Duisburg-Essen , Essen, Germany .
authors.forename: Holger
authors.initials: H
authors.lastname: Jastrow
authors.affiliation: 4 Department of Radiotherapy, University Hospital, University of Duisburg-Essen , Essen, Germany .
authors.forename: Martin
authors.initials: M
authors.lastname: Stuschke
authors.affiliation: 1 Institute of Cell Biology (Cancer Research), University Hospital, University of Duisburg-Essen , Essen, Germany .
authors.forename: Verena
authors.initials: V
authors.lastname: Jendrossek
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D018932:Chemokine CCL2 / Q000378:metabolism; D008168:Lung / Q000528:radiation effects; D008175:Lung Neoplasms / Q000209:etiology / Q000517:prevention & control* / Q000556:secondary; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D045164:Mesenchymal Stem Cell Transplantation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D011832:Radiation Injuries / Q000517:prevention & control; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism
chemical_list: D018932:Chemokine CCL2; D019716:Tissue Inhibitor of Metalloproteinase-2; D020778:Matrix Metalloproteinase 2