title: A 3D-microtissue-based phenotypic screening of radiation resistant tumor cells with synchronized chemotherapeutic treatment.
abstract: BACKGROUND
  Radiation resistance presents a challenge to the effective treatment of cancer. If therapeutic compounds were capable of resensitizing resistant tumours then a concurrent chemo-radiation treatment could be used to overcome radiation resistance.
  
  
  METHODS
  We have developed a phenotypic assay to investigate the response of radiation resistant breast cancer cells grown in 3D-microtissue spheroids to combinations of radiation and established chemotherapeutic drugs. The effects were quantified by real time high content imaging of GFP detection area over 14 days. Ten established chemotherapeutic drugs were tested for their ability to enhance the effects of radiation.
  
  
  RESULTS
  Of ten analysed chemotherapeutics, vinblastine was the most effective compound, with docetaxel and doxorubicine being less effective in combination with radiation. To investigate the response in a model closer to the in vivo situation we investigated the response of heterotypic 3D microtissues containing both fibroblasts and breast cancer cells. Drug treatment of these heterotypic 3D cultures confirmed treatment with radiation plus vinblastine to be additive in causing breast cancer growth inhibition. We have validated the screen by comparing radiation sensitizing effects of known chemotherapeutic agents. In both monotypic and heterotypic models the concurrent treatment of vinblastine and radiation proved more effective inhibitors of mammary cancer cell growth. The effective concentration range of both vinblastine and radiation are within the range used in treatment, suggesting the 3D model will offer a highly relevant screen for novel compounds.
  
  
  CONCLUSIONS
  For the first time comfortable 3D cell-based phenotypic assay is available, that allows high throughput screening of compounds with radiation therapy modulating capacity, opening the field to drug discovery.
authors.affiliation: Institute of Radiation Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, Ingolstaedter Landstr. 1, 85764, Neuherberg, Germany. natasa.anastasov@helmholtz-muenchen.de.
authors.forename: Nataša
authors.initials: N
authors.lastname: Anastasov
authors.affiliation: Institute of Radiation Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, Ingolstaedter Landstr. 1, 85764, Neuherberg, Germany. ines.hoefig@helmholtz-muenchen.de.
authors.forename: Ines
authors.initials: I
authors.lastname: Höfig
authors.affiliation: Institute of Radiation Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, Ingolstaedter Landstr. 1, 85764, Neuherberg, Germany. vanja.radulovic@helmholtz-muenchen.de.
authors.forename: Vanja
authors.initials: V
authors.lastname: Radulović
authors.affiliation: Insphero AG, Schlieren, Switzerland. simon.stroebel@insphero.com.
authors.forename: Simon
authors.initials: S
authors.lastname: Ströbel
authors.affiliation: Sirion Biotech GmbH, Martinsried, Germany. Salomon@sirion-biotech.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Salomon
authors.affiliation: Insphero AG, Schlieren, Switzerland. jan.lichtenberg@insphero.com.
authors.forename: Jan
authors.initials: J
authors.lastname: Lichtenberg
authors.affiliation: Assay Development and Screening Platform, Institute of molecular Toxicology and Pharmacology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany. ina.rothenaigner@helmholtz-muenchen.de.
authors.forename: Ina
authors.initials: I
authors.lastname: Rothenaigner
authors.affiliation: Assay Development and Screening Platform, Institute of molecular Toxicology and Pharmacology, Helmholtz Zentrum München - German Research Center for Environmental Health, Neuherberg, Germany. kamyar.hadian@helmholtz-muenchen.de.
authors.forename: Kamyar
authors.initials: K
authors.lastname: Hadian
authors.affiliation: Insphero AG, Schlieren, Switzerland. jens.kelm@insphero.com.
authors.forename: Jens M
authors.initials: JM
authors.lastname: Kelm
authors.affiliation: Sirion Biotech GmbH, Martinsried, Germany. thirion@sirion-biotech.de.
authors.forename: Christian
authors.initials: C
authors.lastname: Thirion
authors.affiliation: Institute of Radiation Biology, Helmholtz Zentrum München - German Research Center for Environmental Health, Ingolstaedter Landstr. 1, 85764, Neuherberg, Germany. atkinson@helmholtz-muenchen.de.|Chair of Radiation Biology, Technical University of Munich, Munich, Germany. atkinson@helmholtz-muenchen.de.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Atkinson
mesh_terms: D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D018929:Cell Culture Techniques / Q000379:methods*; D045744:Cell Line, Tumor / Q000187:drug effects / Q000528:radiation effects; D000077143:Docetaxel; D004317:Doxorubicin / Q000008:administration & dosage; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D011836:Radiation Tolerance / Q000187:drug effects*; D043823:Taxoids / Q000008:administration & dosage; D014747:Vinblastine / Q000008:administration & dosage
chemical_list: D043823:Taxoids; D000077143:Docetaxel; D014747:Vinblastine; D004317:Doxorubicin