title: In vitro irradiation system for radiobiological experiments.
abstract: BACKGROUND
  Although two-dimensional (2-D) monolayer cell cultures provide important information on basic tumor biology and radiobiology, they are not representative of the complexity of three-dimensional (3-D) solid tumors. In particular, new models reproducing clinical conditions as closely as possible are needed for radiobiological studies to provide information that can be translated from bench to bedside.
  
  
  METHODS
  We developed a novel system for the irradiation, under sterile conditions, of 3-D tumor spheroids, the in vitro model considered as a bridge between the complex architectural organization of in vivo tumors and the very simple one of in vitro monolayer cell cultures. The system exploits the same equipment as that used for patient treatments, without the need for dedicated and highly expensive instruments. To mimic the passage of radiation beams through human tissues before they reach the target tumor mass, 96-multiwell plates containing the multicellular tumor spheroids (MCTS) are inserted into a custom-built phantom made of plexiglass, the material most similar to water, the main component of human tissue.
  
  
  RESULTS
  The system was used to irradiate CAEP- and A549-derived MCTS, pre-treated or not with 20 μM cisplatin, with a dose of 20 Gy delivered in one session. We also tested the same treatment schemes on monolayer CAEP and A549 cells. Our preliminary results indicated a significant increment in radiotoxicity 20 days after the end of irradiation in the CAEP spheroids pre-treated with cisplatin compared to those treated with cisplatin or irradiation alone. Conversely, the effect of the radio- chemotherapy combination in A549-derived MCTS was similar to that induced by cisplatin or irradiation alone. Finally, the 20 Gy dose did not affect cell survival in monolayer CAEP and A549 cells, whereas cisplatin or cisplatin plus radiation caused 100% cell death, regardless of the type of cell line used.
  
  
  CONCLUSIONS
  We set up a system for the irradiation, under sterile conditions, of tumor cells grown in 3-D which allows for the use of the same dose intensities and schedules utilized in clinical practice. This irradiation system, coupled with 3-D cell cultures, has the potential to generate information that could be used to individually tailor radiotherapy.
authors.affiliation: Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Biosciences Laboratory, via P, Maroncelli 40, 47014, Meldola, FC, Italy. anna.tesei@irst.emr.it.
authors.forename: Anna
authors.initials: A
authors.lastname: Tesei
authors.forename: Anna
authors.initials: A
authors.lastname: Sarnelli
authors.forename: Chiara
authors.initials: C
authors.lastname: Arienti
authors.forename: Enrico
authors.initials: E
authors.lastname: Menghi
authors.forename: Laura
authors.initials: L
authors.lastname: Medri
authors.forename: Elisa
authors.initials: E
authors.lastname: Gabucci
authors.forename: Sara
authors.initials: S
authors.lastname: Pignatta
authors.forename: Mirella
authors.initials: M
authors.lastname: Falconi
authors.forename: Rosella
authors.initials: R
authors.lastname: Silvestrini
authors.forename: Wainer
authors.initials: W
authors.lastname: Zoli
authors.forename: Vincenzo
authors.initials: V
authors.lastname: D'Errico
authors.forename: Antonino
authors.initials: A
authors.lastname: Romeo
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Parisi
authors.forename: Rolando
authors.initials: R
authors.lastname: Polico
mesh_terms: D000818:Animals; D019149:Bioreactors; D018929:Cell Culture Techniques / Q000379:methods*; D045744:Cell Line, Tumor; D002470:Cell Survival; D002478:Cells, Cultured; D002945:Cisplatin / Q000008:administration & dosage; D019583:Dose Fractionation, Radiation; D006801:Humans; D007150:Immunohistochemistry; D016014:Linear Models; D046529:Microscopy, Electron, Transmission; D011853:Radiobiology / Q000379:methods; D011874:Radiometry / Q000379:methods; D011878:Radiotherapy / Q000379:methods*; D012107:Research Design; D018874:Spheroids, Cellular / Q000473:pathology* / Q000528:radiation effects*; D014407:Tumor Cells, Cultured
chemical_list: D002945:Cisplatin