title: The PCC assay can be used to predict radiosensitivity in biopsy cultures irradiated with different types of radiation.
abstract: The aim of this study was to identify potential biomarkers for radiosensitivity using the relationship between cell killing and the yield of excess chromatin fragments detected with the premature chromosome condensation (PCC) technique. This method was applied to primary cultured cells obtained from biopsies from patients. Six primary culture biopsies were obtained from 6 patients with carcinoma of the cervix before starting radiotherapy. The cultures were irradiated with two different LET carbon-ion beams (LET = 13 keV/microm, 77.1+/-2.8 keV/microm) and 200 kV X-rays. The carbon-ion beams were produced by Heavy Ion Medical Accelerator in Chiba (HIMAC). PCC was performed using the polyethylene glycol-mediated cell fusion technique. The yield of excess chromatin fragments were measured by counting the number of unrejoined chromatin fragments detected with the PCC technique after a 24-h post-irradiation incubation period. Obtained results indicated that cultures which were more sensitive to killing were also more susceptible to the induction of excess chromatin fragments. Furthermore there was a good correlation between cell killing and excess chromatin fragments among the 6 cell cultures examined. There is also evidence that the induction of excess chromatin fragments increased with increasing LET as well as cell-killing effect in the same cell culture. The data reported here support the idea that the yield of excess chromatin fragments detected with the PCC technique might be useful for predicting the radiosensitivity of cells contained in tumor tissue, and to predict responses to different radiation types.
authors.affiliation: Heavy-ion Radiobiology Research Group, National Institute of Radiological Sciences, Chiba 263, Japan. m_suzuki@nirs.go.jp
authors.forename: Masao
authors.initials: M
authors.lastname: Suzuki
authors.forename: Chizuru
authors.initials: C
authors.lastname: Tsuruoka
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakano
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ohno
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Furusawa
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Okayasu
mesh_terms: D015415:Biomarkers; D001706:Biopsy; D002244:Carbon / Q000737:chemistry; D045744:Cell Line, Tumor; D002843:Chromatin / Q000528:radiation effects*; D019457:Chromosome Breakage; D005260:Female; D020450:Heavy Ions; D006801:Humans; D018499:Linear Energy Transfer; D011829:Radiation Dosage; D011836:Radiation Tolerance; D014594:Uterine Neoplasms; D014965:X-Rays
chemical_list: D015415:Biomarkers; D002843:Chromatin; D002244:Carbon