title: Radiosensitivity of Prostate Cancer Cell Lines for Irradiation from Beta Particle-emitting Radionuclide ¹⁷⁷Lu Compared to Alpha Particles and Gamma Rays.
abstract: OBJECTIVE
  The purpose of the present study was to investigate the radiosensitivity of the prostate cancer cell lines LNCaP, DU145, and PC3 when irradiated with beta particles emitted from (177)Lu, and to compare the effect with irradiation using alpha particles or gamma rays.
  
  
  METHODS
  Cells were irradiated with beta particles emitted from (177)Lu, alpha particles from (241)Am, or gamma rays from (137)Cs. A non-specific polyclonal antibody was labeled with (177)Lu and used to irradiate cells in suspension with beta particles. A previously described in-house developed alpha-particle irradiator based on a (241)Am source was used to irradiate cells with alpha particles. External gamma-ray irradiation was achieved using a standard (137)Cs irradiator. Cells were irradiated to absorbed doses equal to 0, 0.5, 1, 2, 4, 6, 8, or 10 Gy. The absorbed doses were calculated as mean absorbed doses. For evaluation of cell survival, the tetrazolium-based WST-1 assay was used. After irradiation, WST-1 was added to the cell solutions, incubated, and then measured for level of absorbance at 450 nm, indicating the live and viable cells.
  
  
  RESULTS
  LNCaP, DU145, and PC3 cell lines all had similar patterns of survival for the different radiation types. No significant difference in surviving fractions were observed between cells treated with beta-particle and gamma-ray irradiation, represented for example by the surviving fraction values (mean±SD) at 2, 6, and 10 Gy (SF2, SF6, and SF10) for DU145 after beta-particle irradiation: 0.700±0.090, 0.186±0.050 and 0.056±0.010, respectively. A strong radiosensitivity to alpha particles was observed, with SF2 values of 0.048±0.008, 0.018±0.006 and 0.015±0.005 for LNCaP, DU145, and PC3, respectively.
  
  
  CONCLUSIONS
  The surviving fractions after irradiation using beta particles or gamma rays did not differ significantly at the absorbed dose levels and dose rates used. Irradiation using alpha particles led to a high level of cell killing. The results show that the beta-particle emitter (177)Lu as well as alpha-particles are both good candidates for radionuclide-therapy applications in the treatment of prostate cancer.
authors.affiliation: Department of Medical Radiation Physics, Institute of Clinical Sciences, Lund University, Lund, Sweden jorgen.elgqvist@gmail.com.
authors.forename: Jörgen
authors.initials: J
authors.lastname: Elgqvist
authors.affiliation: Department of Medical Radiation Physics, Institute of Clinical Sciences, Lund University, Lund, Sweden.
authors.forename: Oskar Vilhelmsson
authors.initials: OV
authors.lastname: Timmermand
authors.affiliation: Department of Radiation Physics, Skåne University Hospital, Lund, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Larsson
authors.affiliation: Department of Medical Radiation Physics, Institute of Clinical Sciences, Lund University, Lund, Sweden.
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Strand
mesh_terms: D000512:Alpha Particles; D000576:Americium; D001610:Beta Particles; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D006801:Humans; D008187:Lutetium; D008297:Male; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011836:Radiation Tolerance; D011868:Radioisotopes
chemical_list: D011868:Radioisotopes; D008187:Lutetium; D000576:Americium
keywords: Radiosensitivity; alpha particles; beta particles; gamma rays; prostate cancer