title: In vitro comparison of conventional hyperthermia and modulated electro-hyperthermia.
abstract: Radiofrequency-induced hyperthermia (HT) treatments for cancer include conventional capacitive coupling hyperthermia (cCHT) and modulated electro-hyperthermia (mEHT). In this study, we directly compared these methods with regard to in vitro cytotoxicity and mechanisms of action under isothermal conditions. Hepatoma (HepG2) cells were exposed to HT treatment (42°C for 30 min) using mEHT, cCHT or a water bath. mEHT produced a much higher apoptosis rate (43.1% ± 5.8%) than cCHT (10.0% ± 0.6%), the water bath (8.4% ± 1.7%) or a 37°C control (6.6% ± 1.1%). The apoptosis-inducing effect of mEHT at 42°C was similar to that achieved with a water bath at 46°C. mEHT also increased expression of caspase-3, 8 and 9. All three hyperthermia methods increased intracellular heat shock protein 70 (Hsp70) levels, but only mEHT greatly increased the release of Hsp70 from cells. Calreticulin and E-cadherin levels in the cell membrane also increased after mEHT treatment, but not after cCHT or water bath. These results suggest that mEHT selectively deposits energy on the cell membrane and may be a useful treatment modality that targets cancer cell membranes.
authors.affiliation: Department of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.|Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan.|School of Medicine, Fu Jen Catholic University, New Taipei, Taiwan.
authors.forename: Kai-Lin
authors.initials: KL
authors.lastname: Yang
authors.affiliation: Department of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
authors.forename: Cheng-Chung
authors.initials: CC
authors.lastname: Huang
authors.affiliation: Department of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
authors.forename: Mau-Shin
authors.initials: MS
authors.lastname: Chi
authors.affiliation: Department of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
authors.forename: Hsin-Chien
authors.initials: HC
authors.lastname: Chiang
authors.affiliation: Department of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
authors.forename: Yu-Shan
authors.initials: YS
authors.lastname: Wang
authors.affiliation: Institute of Nuclear Energy Research, Taoyuan, Taiwan.
authors.forename: Chien-Chung
authors.initials: CC
authors.lastname: Hsia
authors.affiliation: Department of Radiological Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Japan.
authors.forename: Gabor
authors.initials: G
authors.lastname: Andocs
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Hsin-Ell
authors.initials: HE
authors.lastname: Wang
authors.affiliation: Department of Radiation Therapy and Oncology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.|Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan.|Institute of Veterinary Clinical Science, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Kwan-Hwa
authors.initials: KH
authors.lastname: Chi
mesh_terms: D017209:Apoptosis; D015820:Cadherins / Q000378:metabolism; D037282:Calreticulin / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D056945:Hep G2 Cells; D006358:Hot Temperature; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D061986:MCF-7 Cells; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology; D017382:Reactive Oxygen Species / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
chemical_list: D015820:Cadherins; D037282:Calreticulin; D018840:HSP70 Heat-Shock Proteins; D017382:Reactive Oxygen Species; D051176:beta Catenin; D020169:Caspases
keywords: cell membrane; conventional capacitive coupling hyperthermia; cytotoxicity; modulated electro-hyperthermia; water bath