Analysis of gene expression in normal and cancer cells exposed to gamma-radiation

Abstract

The expression of many genes is modulated after exposure to ionizing radiation. Identification of specific genes may allow the determination of pathways important in radiation responses. We previously identified modulation of the expression of several genes in response to ionizing radiation treatment. In the present study, we monitored the expression of RGS1, CC3, THBS1, vWF, MADH7, and a novel gene encoding a secreted protein in irradiated Jurkat, TK6, HeLa, and HFL1 cells. The RGS1 is involved in G-protein signaling pathway, CC3 belongs to the complement system, THBS1 is a component of the extracellular matrix, vWF takes part in blood coagulation, and MADH7 is a member of the TGF-beta signal transduction pathway. Our objective was to find similarities and differences in the expression of these genes in ionizing radiation-exposed diverse cell types. RGS1 was downregulated in Jurkat cells but was upregulated in TK6 and HFL1 cells. The expression of CC3 was repressed in Jurkat and HFL1 cells but was induced in TK6 and HeLa cells. THBS1 was downregulated in irradiated TK6 and HFL1 cells. vWF was induced in radiation-exposed HeLa cells, but its expression was downregulated in Jurkat cells. The expression of MADH7 was induced in all the cell types examined. These results indicate cell specific modulation of gene expression and suggest the involvement of different pathways in cellular response to radiation treatment in different cells.

Figure 1

Ionizing radiation-induced gene expression in Jurkat cells. (a) The expression ratios of various genes at 4-, 8-, 12-, and 24-hour time points compared to unirradiated sham control. (b) Agarose gel images of relative quantative RT-PCR for various genes. In all cases, the upper gel band represents gene-specific amplification and the lower gel band indicates the relative amplification of β-actin internal standards.

Figure 2

The gene expression in ionizing radiation treated TK6 cells. The expression ratios for various genes at 4, 8, 12, and 24 hours after radiation exposure were determined and compared to the control mock irradiated cells.

Figure 3

The expression of RGS1, CC3, THBS1, vWF, MADH7, and Sec Pro at various time points in irradiated HeLa cells.

Figure 4

The expression of RGS1, CC3, THBS1, vWF, MADH7, and Sec Pro at 4-, 8-, 12-, and 24-hour time points in irradiated HFL1 cells.