Dose- and time-dependent changes of micronucleus frequency and gene expression in the progeny of irradiated cells: Two components in radiation-induced genomic instability?

作者：Huumonen Katriina; Korkalainen Merja; Boman Eeva; Heikkila Janne; Hoyto Anne; Lahtinen Tapani; Luukkonen Jukka; Viluksela Matti; Naarala Jonne; Juutilainen Jukka^*

来源：Mutation Research-Fundamental and Molecular Mechanisms of Mutagenesis, 2014, 765: 32-39.

DOI：10.1016/j.mrfmmm.2014.04.010

• Dose-response
• X-rays
• Delayed effects
• Radiation-induced genomic instability

Murine embryonic C3H/10T1/2 fibroblasts were exposed to X-rays at doses of 0.2, 0.5, 1, 2 or 5 Gy. To follow the development of radiation-induced genomic instability (RIGI), the frequency of micronuclei was measured with flow cytometry at 2 days after exposure and in the progeny of the irradiated cells at 8 and 15 days after exposure. Gene expression was measured at the same points in time by PCR arrays profiling the expression of 84 cancer-relevant genes. The micronucleus results showed a gradual decrease in the slope of the dose-response curve between days 2 and 15. The data were consistent with a model assuming two components in RIG!. The first component is characterized by dose-dependent increase in micronuclei. It may persist more than ten cell generations depending on dose, but eventually disappears. The second component is more persistent and independent of dose above a threshold higher than 0.2 Gy. Gene expression analysis 2 days after irradiation at 5 Gy showed consistent changes in genes that typically respond to DNA damage. However, the consistency of changes decreased with time, suggesting that non-specificity and increased heterogeneity of gene expression are characteristic to the second, more persistent component of RIGI.

• 出版日期2014-7