Mechanisms of Antitumor Activity of Low Doses of Radiation Associated with Activation of Cells' Defense System.

Background: The effects of ionizing radiation (IR) involve a highly orchestrated series of events in cells, including DNA damage and repair, cell death, and changes in the level of proliferation associated with the stage of the cell cycle. A large number of existing studies in literature have examined the activity of genes and their regulators in mammalian cells in response to high doses of ionizing radiation. Although there are many studies, the research in effect of low doses of ionizing radiation remains limited.

Changes in the Activity of Genes Involved in the Regulation of Hematopoiesis during Tumorigenesis in Irradiated Mice.

We used 183 F1 CBA×C57Bl hybrid mice to study the delayed effects of low-power long-term γ-irradiation at a dose of 12.6 Gy (10 mGy/min) 8 and 10 months after the treatment. Eight months after the treatment we found the increased expression of the transcription factor NFκB and its target genes iNOS and G-SCF in the bone marrow (BM).

[Searching Radiation Countermeasures using the Model of Prolonged Irradiation of Mice with Low Dose Rate and Evaluation of Their Influence on Heat Shock Protein Genes Expression].

Different radiomodificators (cytokine betaleukine, antioxidant phenoxan, antigipoksant limontar and nucleoside riboxin) were investigated on mice for evaluating their radiation protective capacity against prolonged (21 h) exposure at a dose of 12.6 Gy at a low dose rate of 10 mGy/min. Bone marrow cellularity and endogenic CFUs were used as evaluation criteria 9 days after exposure.

[Comparative analysis of natural and synthetic antimutagens as regulators of gene expression in human cells under exposure to ionizing radiation].

This paper studies the effect of plant peptides of thionine Ns-W2 extracted from seeds of fennel flower (Nigella sativa) and β-purothionine from wheat germs (Triticum kiharae), as well as a synthetic antimutagen (crown-compound), on the expression of several genes involved in the.control of cellular homeostasis, processes of carcinogenesis, and radiation response in human rhabdomyosarcoma cells (RD cells), T-lymphoblastoid cell line Jurkat, and blood cells. All of these agents acted as antimutagens-anticarcinogens, reducing the expression of genes involved in carcinogenesis (genes of families MMP, TIMP, and IAP and G-protein genes) in a tumor cell.