title: Influence of P53 on the radiotherapy response of hepatocellular carcinoma.
abstract: OBJECTIVE
  Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and it has a poor prognosis and few therapeutic options. Radiotherapy is one of the most effective forms of cancer treatment, and P53 protein is one of the key molecules determining how a cell responds to radiotherapy. The aim of this study was to determine the therapeutic efficacy of iodine-131 in three human HCC cell lines.
  
  
  METHODS
  Western blotting was used to measure P53 expression. The effects of radiotherapy with iodine-131 were assessed by using the clonogenic assay to evaluate cell survival. Flow cytometry was carried out to examine the effects of iodine-131 on cell death, oxidative stress, reduced intracellular glutathione expression, the mitochondrial membrane potential, and the cell cycle.
  
  
  RESULTS
  The P53 protein was not expressed in Hep3B2.1-7 cells, was expressed at normal levels in HepG2 cells, and was overexpressed in HuH7 cells. P53 expression in the HuH7 and HepG2 cell lines increased after internal and external irradiation with iodine-131. Irradiation induced a decrease in cell survival and led to a decrease in cell viability in all of the cell lines studied, accompanied by cell death via late apoptosis/necrosis and necrosis. Irradiation with 131-iodine induced mostly cell-cycle arrest in the G0/G1 phase.
  
  
  CONCLUSIONS
  These results suggest that P53 plays a key role in the radiotherapy response of HCC.
authors.affiliation: Biophysics Unit, Faculty of Medicine of University of Coimbra, Coimbra, Portugal.
authors.forename: Ana R
authors.initials: AR
authors.lastname: Gomes
authors.affiliation: Biophysics Unit, Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; Center of Investigation on Environmental, Genetics and Oncobiology (CIMAGO), Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; CNC.IBILI, University of Coimbra, Coimbra, Portugal.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Abrantes
authors.affiliation: Biophysics Unit, Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; Center of Investigation on Environmental, Genetics and Oncobiology (CIMAGO), Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; CNC.IBILI, University of Coimbra, Coimbra, Portugal.
authors.forename: Ana F
authors.initials: AF
authors.lastname: Brito
authors.affiliation: Biophysics Unit, Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; Center of Investigation on Environmental, Genetics and Oncobiology (CIMAGO), Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; CNC.IBILI, University of Coimbra, Coimbra, Portugal.
authors.forename: Mafalda
authors.initials: M
authors.lastname: Laranjo
authors.affiliation: Biophysics Unit, Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; Center of Investigation on Environmental, Genetics and Oncobiology (CIMAGO), Faculty of Medicine of University of Coimbra, Coimbra, Portugal.
authors.forename: João E
authors.initials: JE
authors.lastname: Casalta-Lopes
authors.affiliation: Center of Investigation on Environmental, Genetics and Oncobiology (CIMAGO), Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; CNC.IBILI, University of Coimbra, Coimbra, Portugal. ; Applied Molecular Biology and Hematology Group, Faculty of Medicine of University of Coimbra, Coimbra, Portugal.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Gonçalves
authors.affiliation: Center of Investigation on Environmental, Genetics and Oncobiology (CIMAGO), Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; CNC.IBILI, University of Coimbra, Coimbra, Portugal. ; Applied Molecular Biology and Hematology Group, Faculty of Medicine of University of Coimbra, Coimbra, Portugal.
authors.forename: Ana B
authors.initials: AB
authors.lastname: Sarmento-Ribeiro
authors.affiliation: Biophysics Unit, Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; Center of Investigation on Environmental, Genetics and Oncobiology (CIMAGO), Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; CNC.IBILI, University of Coimbra, Coimbra, Portugal.
authors.forename: Maria F
authors.initials: MF
authors.lastname: Botelho
authors.affiliation: Biophysics Unit, Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; Center of Investigation on Environmental, Genetics and Oncobiology (CIMAGO), Faculty of Medicine of University of Coimbra, Coimbra, Portugal. ; Surgical Department A, CHUC, Coimbra, Portugal.
authors.forename: José G
authors.initials: JG
authors.lastname: Tralhão
mesh_terms: D017209:Apoptosis / Q000528:radiation effects*; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D059585:G1 Phase Cell Cycle Checkpoints / Q000528:radiation effects; D005720:Gamma Rays; D005978:Glutathione / Q000378:metabolism; D056945:Hep G2 Cells; D006801:Humans; D007457:Iodine Radioisotopes / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy; D010766:Phosphorylation; D017382:Reactive Oxygen Species / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D007457:Iodine Radioisotopes; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; D005978:Glutathione
keywords: Hepatocellular carcinoma; Iodine-131; P53; Radiotherapy