title: Cancer-associated fibroblasts from human NSCLC survive ablative doses of radiation but their invasive capacity is reduced.
abstract: BACKGROUND
  Cancer-Associated Fibroblasts (CAFs) are significant components of solid malignancies and play central roles in cancer sustainability, invasion and metastasis. In this study we have investigated the invasive capacity and matrix remodelling properties of human lung CAFs after exposure to ablative doses of ionizing radiation (AIR), equivalent to single fractions delivered by stereotactic ablative radiotherapy (SART) for medically inoperable stage-I/II non-small-cell lung cancers.
  
  
  METHODS
  CAFs were isolated from lung tumour specimens from 16 donors. Initially, intrinsic radiosensitivity was evaluated by checking viability and extent of DNA-damage response (DDR) at different radiation doses. The migrative and invasive capacities of CAFs were thereafter determined after a sub-lethal single radiation dose of 18 Gy. To ascertain the mechanisms behind the altered invasive capacity of cells, expression of matrix metalloproteinases (MMPs) and their endogenous inhibitors (TIMPs) were measured in the conditioned media several days post-irradiation, along with expression of cell surface integrins and dynamics of focal contacts by vinculin-staining.
  
  
  RESULTS
  Exposing CAFs to 1 × 18 Gy resulted in a potent induction of multiple nuclear DDR foci (> 9/cell) with little resolution after 120 h, induced premature cellular senescence and inhibition of the proliferative, migrative and invasive capacity. AIR promoted MMP-3 and inhibited MMP-1 appearance to some extent, but did not affect expression of other major MMPs. Furthermore, surface expression of integrins α2, β1 and α5 was consistently enhanced, and a dramatic augmentation and redistribution of focal contacts was observed.
  
  
  CONCLUSIONS
  Our data indicate that ablative doses of radiation exert advantageous inhibitory effects on the proliferative, migratory and invasive capacity of lung CAFs. The reduced motility of irradiated CAFs might be a consequence of stabilized focal contacts via integrins.
authors.affiliation: Department of Oncology, University Hospital of Northern Norway, 9038 Tromsø, Norway.
authors.forename: Turid
authors.initials: T
authors.lastname: Hellevik
authors.forename: Ingvild
authors.initials: I
authors.lastname: Pettersen
authors.forename: Vivian
authors.initials: V
authors.lastname: Berg
authors.forename: Jan Olof
authors.initials: JO
authors.lastname: Winberg
authors.forename: Bjørn T
authors.initials: BT
authors.lastname: Moe
authors.forename: Kristian
authors.initials: K
authors.lastname: Bartnes
authors.forename: Ruth H
authors.initials: RH
authors.lastname: Paulssen
authors.forename: Lill-Tove
authors.initials: LT
authors.lastname: Busund
authors.forename: Roy
authors.initials: R
authors.lastname: Bremnes
authors.forename: Anthony
authors.initials: A
authors.lastname: Chalmers
authors.forename: Iñigo
authors.initials: I
authors.lastname: Martinez-Zubiaurre
mesh_terms: D000368:Aged; D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology*; D002448:Cell Adhesion / Q000528:radiation effects; D002455:Cell Division / Q000528:radiation effects; D002465:Cell Movement / Q000528:radiation effects; D002478:Cells, Cultured / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects; D016922:Cellular Senescence / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D004790:Enzyme Induction; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects*; D022001:Focal Adhesions; D006801:Humans; D016023:Integrins / Q000096:biosynthesis / Q000235:genetics; D008175:Lung Neoplasms / Q000473:pathology*; D008297:Male; D020782:Matrix Metalloproteinases / Q000096:biosynthesis / Q000235:genetics; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D010315:Particle Accelerators; D011836:Radiation Tolerance; D016634:Radiosurgery; D017154:Stromal Cells / Q000473:pathology; D019714:Tissue Inhibitor of Metalloproteinases / Q000096:biosynthesis / Q000235:genetics
chemical_list: D016023:Integrins; D019714:Tissue Inhibitor of Metalloproteinases; D020782:Matrix Metalloproteinases