The Effect of Low Doses of Ionizing Radiation on Expression of Genes and Noncoding RNA in Normal and Malignant Human Cells

The effect of X-ray radiation (0.1 Gy) on the expression of a number of genes and regulatory RNA (miRNA and long noncoding RNA) in human lymphocytes and T-lymphoblastic cells (Jurkat cells) was studied. One hour after cell irradiation with a low dose of radiation, lymphocytes displayed p53 expression and a decreased level of mature miR-27a and miR-181a having mRNA of gene p53 as target. These cells also had inhibited NFkB activity, which was found from reduced mRNA content of RhoA cdc42 and IL6 genes. By 4 h, their expression was normalized. Unlike in the case of normal cells, increased content of mRNA of NFkB gene ( p65 ) and mRNA of its target IL6 gene was observed in Jurkat cells during this period. Repeated irradiation of cells with 5 Gy carried out after 4 h showed the radiation adaptive response (AO) according to the criterion of lymphocyte survival and its absence in Jurkat cells. The difference between groups of 5 Gy and 0.1 + 5 Gy in lymphocytes that survived after 20 h revealed common AO features (mRNA of p53 gene, NEAT1, miR-181a, miR-107). The results indicate the activation of various intracellular systems after the stress with low doses of radiation on lymphocytes and Jurkat cells. This approach can be used to optimize the efficacy of radiation therapy when preirradiation with a small dose of radiation increases the radioresistance of normal tissues surrounding a tumor.