title: Effects of Platinum Nanocolloid in Combination with Gamma Irradiation on Normal Human Esophageal Epithelial Cells.
abstract: Our previous study demonstrated that platinum nanocolloid (Pt-nc), combined with lower-dose gamma irradiation at 3, 5, and 7 Gy significantly decreased proliferation and accelerated apoptosis of the human esophageal squamous cell carcinoma-derived cell line KYSE-70. The aim of the present study was to determine, under the same conditions as our previous study where gamma rays combined with Pt-nc were carcinostatic to KYSE-70 cells, if we could induce a radioprotective or the radiation-sensitizing effect on the human normal esophageal epithelial cells (HEEpiC). HEEpiC were treated with various Pt-nc concentrations and then irradiated with various gamma-ray doses. The proliferative status of HEEpiC was evaluated using trypan blue dye-exclusion and WST-8 assays. The cellular and nucleic morphological features were determined using crystal violet and Hoechst 33342 stainings, respectively. The intracellular level of reactive oxygen species (ROS) in HEEpiC was evaluated with a nitro blue tetrazolium (NBT) assay. The apoptotic status was detected with caspase-3, Bax, and Bcl-2 by Western blotting. Either Pt-nc or gamma irradiation could inhibit the growth of HEEpiC; however, their combined use exerted a significant proliferation-inhibitory effect in a Pt-nc dose-dependent manner than gamma irradiation alone. Pt-nc resulted in radiation sensitization rather than radiation protection on HEEpiC in vitro similar to KYSE-70 cells, when Pt-nc was administrated alone or combined with gamma irradiation. Thus, Pt-nc has an inhibitory effect on cell proliferation, a facilitative effect on apoptosis, and a certain degree of toxicity against HEEpiC.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Li
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Saitoh
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Miwa
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D003102:Colloids / Q000008:administration & dosage / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004847:Epithelial Cells / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D004947:Esophagus / Q000166:cytology* / Q000187:drug effects / Q000528:radiation effects; D005720:Gamma Rays; D006801:Humans; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000008:administration & dosage*; D010984:Platinum / Q000008:administration & dosage*; D011836:Radiation Tolerance / Q000187:drug effects / Q000502:physiology*
chemical_list: D003102:Colloids; D010984:Platinum