title: Hafnium oxide nanoparticles: toward an in vitro predictive biological effect?
abstract: BACKGROUND
  Hafnium oxide, NBTXR3 nanoparticles were designed for high dose energy deposition within cancer cells when exposed to ionizing radiation. The purpose of this study was to assess the possibility of predicting in vitro the biological effect of NBTXR3 nanoparticles when exposed to ionizing radiation.
  
  
  METHODS
  Cellular uptake of NBTXR3 nanoparticles was assessed in a panel of human cancer cell lines (radioresistant and radiosensitive) by transmission electron microscopy. The radioenhancement of NBTXR3 nanoparticles was measured by the clonogenic survival assay.
  
  
  RESULTS
  NBTXR3 nanoparticles were taken up by cells in a concentration dependent manner, forming clusters in the cytoplasm. Differential nanoparticle uptake was observed between epithelial and mesenchymal or glioblastoma cell lines. The dose enhancement factor increased with increase NBTXR3 nanoparticle concentration and radiation dose. Beyond a minimum number of clusters per cell, the radioenhancement of NBTXR3 nanoparticles could be estimated from the radiation dose delivered and the radiosensitivity of the cancer cell lines.
  
  
  CONCLUSIONS
  Our preliminary results suggest a predictable in vitro biological effect of NBTXR3 nanoparticles exposed to ionizing radiation.
authors: Nanobiotix, 60 rue de wattignies, 75012 Paris, France. julie.marill@nanobiotix.com.
authors: Julie
authors: J
authors: Marill
authors: Naeemunnisa Mohamed
authors: NM
authors: Anesary
authors: Ping
authors: P
authors: Zhang
authors: Sonia
authors: S
authors: Vivet
authors: Elsa
authors: E
authors: Borghi
authors: Laurent
authors: L
authors: Levy
authors: Agnes
authors: A
authors: Pottier
mesh_terms: D002470:Cell Survival; D006195:Hafnium / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D053768:Metal Nanoparticles / Q000008:administration & dosage*; D046529:Microscopy, Electron, Transmission; D010087:Oxides / Q000494:pharmacology*; D011829:Radiation Dosage; D011836:Radiation Tolerance / Q000187:drug effects*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D014965:X-Rays
chemical_list: D010087:Oxides; D011838:Radiation-Sensitizing Agents; C545179:hafnium oxide; D006195:Hafnium