Cytotoxicity, genotoxicity and intracellular distribution of the Auger electron emitter (65)Zn in two human cell lines.
Cell survival, induction of apoptosis, and micronucleus formation have been examined in non-transformed human amnion fluid fibroblast-like (AFFL) cells and in a human squameous cell carcinoma (SCL-II) cell line after exposure to the Auger electron emitter (65)Zn and after external low-LET radiation. Cellular uptake and subcellular distribution of (65)Zn(2+) were studied in vitro and the absorbed radiation dose was calculated applying analytical dosimetry models. Auger electrons generated during decay of (65)Zn induced a prominent decrease in cell survival and increased the levels of apoptotic as well as micronucleated cells when compared to external low-LET irradiation. Relative biological effectiveness has been determined for cell survival (RBE approximately 4), micronucleus formation (RBE approximately 2) and apoptosis induction (RBE approximately 5-8) in SCL-II cells and for micronucleus formation (RBE approximately 4-5) and apoptosis induction (RBE approximately 6-10) in AFFL cells, respectively. This demonstrates a general enhanced biological effectiveness of (65)Zn in both investigated cell lines when compared to external low-LET radiation. The distribution pattern of intracellular Zn(2+) was found to be non-uniform, showing enhanced amounts of Zn(2+) in the perinuclear region and low amounts inside the cell nucleus, suggesting a major energy deposition close to the nuclear envelope.
Kriehuber
Ralf
R
Institute of Cell Biology and Biosystems TechnologyDepartment of Biological Sciences, University of Rostock, Albert-Einstein-Strasse 3, 18051, Rostock, Germany. ralf.kriehuber@biologie.uni-rostock.de
Riedling
Manuela
M
Simkó
Myrtill
M
Weiss
Dieter G
DG
D017209:Apoptosis; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000528:radiation effects*; D003114:Colony-Forming Units Assay; D004307:Dose-Response Relationship, Radiation; D004583:Electrons; D006801:Humans; D018499:Linear Energy Transfer; D015162:Micronucleus Tests; D012062:Relative Biological Effectiveness; D015037:Zinc Radioisotopes / Q000494:pharmacology*
D015037:Zinc Radioisotopes