AIM: The aim of this study was to examine the effects of hypoxia on radiosensitivity and to analyze the mechanisms responsible for radiation resistance in gastric and esophageal cancer. MATERIALS AND METHODS: A gastric cancer cell line, OCUM-12, and an esophageal cancer cell line, TE-6, were used. The effects of hypoxia with irradiation on the growth-activity, cell cycle distribution, and gene expression were examined. RESULTS: Both acute and chronic hypoxia decreased radiosensitivity of cancer cells. The radiosensitivity of chronic hypoxic cells was significantly enhanced by reoxygenation. Acute and chronic all hypoxia reduced the percentage of cells in the G(2)/M and S phases, respectively. In acute hypoxia, the mRNA expression of BRCA1 and BRCA2 was reduced in cancer cells. Reoxygenation increased the expression of BRCA1 and BRCA2. CONCLUSION: Hypoxia is associated with radiation resistance. Therefore, reoxygenation may enhance the radiosensitivity of hypoxic cells. BRCA1 and BRCA2 may be associated with factors for radiation resistance by regulation of cell cycle progression.
AIM: The aim of this study was to examine the effects of hypoxia on radiosensitivity and to analyze the mechanisms responsible for radiation resistance in gastric and esophageal cancer. MATERIALS AND METHODS: A gastric cancer cell line, OCUM-12, and an esophageal cancer cell line, TE-6, were used. The effects of hypoxia with irradiation on the growth-activity, cell cycle distribution, and gene expression were examined. RESULTS: Both acute and chronic hypoxia decreased radiosensitivity of cancer cells. The radiosensitivity of chronic hypoxic cells was significantly enhanced by reoxygenation. Acute and chronic all hypoxia reduced the percentage of cells in the G(2)/M and S phases, respectively. In acute hypoxia, the mRNA expression of BRCA1 and BRCA2 was reduced in cancer cells. Reoxygenation increased the expression of BRCA1 and BRCA2. CONCLUSION:Hypoxia is associated with radiation resistance. Therefore, reoxygenation may enhance the radiosensitivity of hypoxic cells. BRCA1 and BRCA2 may be associated with factors for radiation resistance by regulation of cell cycle progression.
Authors: Vlad C Sandulache; Yunyun Chen; Heath D Skinner; Tongtong Lu; Lei Feng; Laurence E Court; Jeffrey N Myers; Raymond E Meyn; Clifton D Fuller; James A Bankson; Stephen Y Lai Journal: Mol Cancer Ther Date: 2015-09-16 Impact factor: 6.261
Authors: Stephan Walrand; Renaud Lhommel; Pierre Goffette; Marc Van den Eynde; Stanislas Pauwels; François Jamar Journal: EJNMMI Res Date: 2012-05-19 Impact factor: 3.138
Authors: Apostolos Menegakis; Rob Klompmaker; Claire Vennin; Aina Arbusà; Maartje Damen; Bram van den Broek; Daniel Zips; Jacco van Rheenen; Lenno Krenning; René H Medema Journal: Cells Date: 2021-03-10 Impact factor: 6.600