title: Modifications in cell cycle kinetics and in expression of G1 phase-regulating proteins in human amniotic cells after exposure to electromagnetic fields and ionizing radiation.
abstract: Low-frequency electromagnetic fields are suspected of being involved in carcinogenesis, particularly in processes that could be related to cancer promotion. Because development of cancer is associated with deregulated cell growth and we previously observed a magnetic field-induced decrease in DNA synthesis [Lange et al. (2002) Alterations in the cell cycle and in the protein level of cyclin D1p, 21CIP1, and p16INK4a after exposure to 50 HZ. MF in human cells. Radiat. Environ. Biophys.41, 131], this study aims to document the influence of 50 Hz, 1 mT magnetic fields (MF), with or without initial gamma-ionizing radiation (IR), on the following cell proliferation-relevant parameters in human amniotic fluid cells (AFC): cell cycle distribution, expression of the G1 phase-regulating proteins Cdk4, cyclin D1, p21CIP1 and p16INK4a, and Cdk4 activity. While IR induced a G1 delay and a dose-dependent G2 arrest, no discernible changes in cell cycle kinetics were observed due to MF exposure. However, a significant decrease in the protein expression of cyclin D1 and an increase in p21CIP1- and p16INK4a-expression could be detected after exposure to MF alone. IR-exposure caused an augmentation of p21CIP1- and p16INK4a- levels as well, but did not alter cyclin D1 expression. A slight diminution of Cdk4 activity was noticed after MF exposure only, indicating that Cdk4 appears not to act as a mediator of MF- or IR-induced changes in the cell cycle of AFC cells. Co-exposure to MF/IR affected neither cell cycle distribution nor protein expression or kinase activity additionally or synergistically, and therefore MF seems not to modify the mutagenic potency of IR.
authors.affiliation: Research Centre Rossendorf, Institute of Bioinorganic and Radiopharmaceutical Chemistry, Dresden, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Lange
authors.forename: T
authors.initials: T
authors.lastname: Viergutz
authors.forename: M
authors.initials: M
authors.lastname: Simkó
mesh_terms: D000650:Amnion / Q000166:cytology; D002453:Cell Cycle / Q000235:genetics / Q000528:radiation effects*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects*; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D002478:Cells, Cultured; D019938:Cyclin D1 / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D051358:Cyclin-Dependent Kinase 4; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D050759:Cyclin-Dependent Kinase Inhibitor p21; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D016213:Cyclins / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D015536:Down-Regulation / Q000235:genetics / Q000528:radiation effects; D004574:Electromagnetic Fields; D005057:Eukaryotic Cells / Q000528:radiation effects*; D016193:G1 Phase / Q000235:genetics / Q000528:radiation effects*; D006801:Humans; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D011839:Radiation, Ionizing
chemical_list: C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D011518:Proto-Oncogene Proteins; D019938:Cyclin D1; C495900:CDK4 protein, human; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases