Project description:The bystander effect from ionizing radiation consists of cellular responses generated from unirradiated cells to the irradiation of their neighbors. The bystander effect can lead to DNA damage and genomic instability in the affected cells. This non-targeted effect of radiation has received attention due to its potential implications for cancer therapy and radiation protection. Although studied extensively, a complete understanding of its molecular mechanism is the subject of ongoing research. While many studies have targeted specific factors which are suggested to be involved in the bystander effect, few have looked at whole genome gene expression in bystander cells. Furthermore, even fewer studies have looked at the expression in noncancerous human cell lines. In this study we have used a genome-wide microarray approach to investigate transcriptional responses in irradiated and bystander immortalized human fibroblasts following 0.1 Gy ?-particle irradiation. Total RNA was isolated from F11hTERT fibroblasts irradiated with 0.1 Gy ?-particles and bystander fibroblasts receiving medium from control (sham irradiated) and irradiated cells (0.1 Gy). RNA was isolated 4, 8 and 26 h after irradiation.
Project description:The bystander effect from ionizing radiation consists of cellular responses generated from unirradiated cells to the irradiation of their neighbors. The bystander effect can lead to DNA damage and genomic instability in the affected cells. This non-targeted effect of radiation has received attention due to its potential implications for cancer therapy and radiation protection. Although studied extensively, a complete understanding of its molecular mechanism is the subject of ongoing research. While many studies have targeted specific factors which are suggested to be involved in the bystander effect, few have looked at whole genome gene expression in bystander cells. Furthermore, even fewer studies have looked at the expression in noncancerous human cell lines. In this study we have used a genome-wide microarray approach to investigate transcriptional responses in irradiated and bystander immortalized human fibroblasts following 0.1 Gy α-particle irradiation.
Project description:The existence of a radiation bystander effect, in which non-irradiated cells respond to signals from irradiated cells, is well established. It raises concerns for the interpretation of risks from exposure to low doses of ionizing radiation. Sparse data exists about the bystander signaling mechanisms and the ability to transmit damaging effects both spatially and temporally. To understand early signaling and cellular changes in bystanders, we have measured global gene expression 30 minutes after direct and bystander exposure to alpha particle in primary human lung fibroblasts. Gene ontology and pathway analyses suggested that the earliest measured changes at 30 minutes after treatment are in cell structure, motility and adhesion categories and a significant number of genes belong to the category of inflammation and cell-to-cell communication. We investigated time course gene expression profiles of matrix metalloproteinases 1 and 3 (MMP1 and MMP3), chemokine ligands 2, 3 and 5 (CXCL2, CXCL3 and CXCL5), interleukins 1a, 1b, 6 and 33 (IL1A, IL1B, IL6 and IL33) growth differentiation factor 15 (GDF15) and superoxide dismutase2 (SOD2) by real time quantitative PCR. These encode proteins involved in cellular signaling via the NFkappaB pathway and time course of mRNA levels revealed an increased response at 30 minutes after irradiation followed by another wave at 4 to 6 hours. We also investigated protein modifications in the AKT-GSK-3 signaling pathway and found that in irradiated cells AKT and GSK3beta are hyper-phosphorylated at 30 minutes and this effect is maintained until 4 hours after exposure. In bystanders there is a similar response with a delay of 30 minutes. In irradiated cells, inactivated GSK3beta led to decreased phosphorylation of beta-catenin. Our results are the first to show that the radiation induced bystander signal can induce a widespread gene expression response as early as 30 minutes after exposure and that these changes are accompanied by protein modification of signaling modules such as AKT and GSK3beta. There are 12 total samples, 4 corresponding biological replicates of IMR90 cells that were not irradiated (control=C), irradiated (alpha=A) and bystander (B), cells were harvested 0.5 hr after treatment
Project description:Transcriptomic profiling of normal mouse thyroid tissue following 211At irradiation Astatine-211 (211At) is an alpha particle emitting halogen with almost optimal linear energy transfer (LET) for creating DNA double strand breaks, and is thus proposed for radionuclide therapy when bound to tumor-seeking agents. Un-bound 211At accumulates in the thyroid gland. The concept of basal radiation-induced biological effects in thyroid tissue is to a high degree unknown and is most valuable. Female BALB/c nude mice were i.v. injected with 0.064-42 kBq of 211At resulting in absorbed doses to the thyroid gland of 0.05-32 Gy. Thyroids were removed at 24 h after injection and total RNA was extracted from pooled thyroids and processed in triplicate using Illumina MouseRef-8 Whole-Genome Expression Beadchips. Nexus Expression 2.0 was used for data analysis. Thyroids exposed to 211At revealed distinctive gene expression profiles compared to non-irradiated controls. More genes were affected at low absorbed doses (0.05 and 0.5 Gy) compared to intermediate (1.4 Gy) and high absorbed doses (11 and 32 Gy) and the proportion of dose-specific genes increased with decreased absorbed dose. This result might be the manifestation of increased heterogeneous irradiation with decreasing absorbed dose, indicating a bystander effect. Also, 1.4 Gy often had an opposite regulation compared to the other absorbed doses. No inflammatory effects were seen while 0.05 and 11 Gy affected the immune system. Effects on the cellular response to outer stress and cell cycle regulation and proliferation were seen at 1.4 and 11 Gy. These results indicate that the cellular response to ionizing radiation is complex and differs with absorbed doses. Total RNA was isolated from fresh-frozen tissue samples (Normal balb/c mouse thyroids)