ABSTRACT: Abstract Purpose: There is a recognised need to develop new methods of high throughput, rapid and minimally invasive individual dose assessment for radiation exposure. The aim of this work is to establish a panel of highly radiation responsive genes suitable for biological dosimetry and to explore inter-individual variation in response to ionising radiation exposure.Materials and method: Analysis of gene expression in response to radiation was carried out using three independent techniques (microarray, Multiplex Quantitative RT-PCR and nCounter Analysis System) in human lymphocytes in culture and circulating blood exposed ex vivo from the same donors. Results: Variations in transcriptional response to exposure to ionising radiation analysed by microarray allowed the identification of genes which can be validated and measured accurately as biomarkers of radiation exposure using other techniques. We have identified genes which are consistently up-regulated following exposure at different time points to either 2 or 4 Gy of X-rays, for all individuals in blood and cultured lymphocytes. Most down-regulated genes including cyclins, centromeric and mitotic checkpoints proteins, particularly those associated with chromosome instability and cancer can only be detected in dividing cells. Conclusions: The data provides evidence that there are a number of genes which seem suitable for biological dosimetry, like SESN1, GADD45A, CDKN1A, CCNG1, FDXR, BBC3 and MDM2. ÊThese biomarkers could potentially be used for triage after large-scale radiological incidents. Variations in transcriptional response accurately measured by MQRT-PCRæ may allow the identification of biomarkers of radiation sensitivity and individual susceptibility and therefore being useful in radiation oncology.
Project description:One of the most likely risks astronauts on long duration space missions face is exposure to ionizing radiation associated with highly energetic and charged heavy (HZE) particles. Since access to medical expertise on such a mission is limited at best, early diagnosis and mitigation of such exposure is critical. In order to accurately determine the dosage within 1 hour post-exposure, dose-dependent “biomarkers” are needed. Therefore, we performed a dose-course transcriptional analysis for radiation exposure at 0, 0.3, 1.5, and 3.0 Gy with corresponding time point at 1 hour (hr) post-exposure using Affymetrix® GeneChip® Human Gene 1.0 ST v1 Array chips. The analysis of our data suggests a set of sensitive genetic biomarkers specific to each radiation level as well as generic radiation response biomarkers. Upregulated biomarkers can then be used within lab-on-a-chip (LOC) systems to detect exposure to ionizing radiation. A total of sixteen human samples representing radiation exposure at levels 0 Gy, 0.3 Gy, 1.5 Gy and 3.0 Gy at time point 1 hour (hr) post-exposure were constructed. Blood samples were extracted from four human volunteers, and were irradiated. Leukocytes were extracted, and gene expression was measured. Samples for all four volunteers were measured at 1 hr for all four dose levels, resulting in four replicates at each dose level. Thus, a total of 4 samples at each of the four radiation levels were sampled, yielding the total of 16 samples.
Project description:Gene expression profiling of normal tissues after curative radiotherapy was carried out to investigate the pathogenesis of late radiation injury in humans. Irradiated and control normal breast tissue was collected from patients undergoing bilateral mastectomy for ipsilateral tumour relapse or prophylaxis following radiotherapy for breast cancer. Using P.A.L.M. laser capture microdissection (LCM) of frozen sections, breast tissue was separated into an epithelial compartment (terminal duct lobular units and ducts) and a stromal compartment (remaining tissue). RNA was extracted, amplified and hybridised to a 20k cDNA array against a breast tissue reference RNA. Expression profiles of irradiated vs control breast were compared for each tissue compartment
Project description:Significant impacts on gene expression were observed generations after exposure in ionising radiation exposed nematodes. C. elegans were exposed to 1 Gy of X-rays and their gene expression was analysed several generations later with whole genome oligoarrays (Washington University).
Project description:Significant impacts on gene expression were observed generations after exposure in ionising radiation exposed nematodes. Overall design: C. elegans were exposed to 1 Gy of X-rays and their gene expression was analysed several generations later with whole genome oligoarrays (Washington University).
Project description:Acquired drug resistance represents a major challenge in chemo-therapy treatment for various types of cancers. We have found that the retinoid X receptor–selective agonist bexarotene (LGD1069, Targretin) was efficacious in treating chemo-resistant cancer cells. The goal of this microarray study was to understand the mechanism of bexarotene’s role in overcoming acquired drug resistance using human breast cancer cells MDA-MB-231 as a model system and paclitaxel as model compound. After MDA-MB-231 cells were repeatedly treated with paclitaxel for 8 cycles with each cycle including a 3-day treatment with 30 nM paclitaxel and followed by a 7-day exposure to control medium, MDA cells resistant to paclitaxel were developed and their growth was no longer inhibited by paclitaxel treatment. Those MDA cells with acquired drug resistance, when treated with paclitaxel and bexarotene in combination, could regain their sensitivity and their growth were again inhibited. Therefore, RNA samples from parental MDA-MB-231 cells, paclitaxel-resistant MDA cells treated with vehicle, paclitaxel alone or in combination with bexarotene, were used for perform global gene expression profiling with Affymetrix HG-U133A gene chips. Keywords: Drug Treatment MDA-MB-231 cells were exposed to regimens on a 10-day cycle: a 3-day treatment with 30 nM paclitaxel and followed by a 7-day exposure to control medium. Paclitaxel resistant MDA-MB-231 cells (MDA-PR) were established within 8 cycles of such treatment (80 days). These MDA-PR cells were then treated with vehicle control, paclitaxel along, or the combination of 30 nM paclitaxel ( 3 days on and 7 days off) and 1 µM Targretin (10 days on) in a new 10-day cycle for 3 months. Thus, there are four treatment groups, parent MDA cells, MDA-PR, MDA-PR treated with paclitaxel, MDA-PR treated with paclitaxel and bexarotene, and each group had four biological replicates.
Project description:au09-03_gamma-irradiation - 2 doses of ionising radiations (x-rays) - Metabolic pathways involved in the response of plants to ionising radiation treatment. - Arabidopsis thaliana (Col-0) seeds were grown in Petri dishes under sterile conditions until they had 2-rosette-leaves (on average 10 days). Then they received a dose of 10 or 40 gray of X-ray (Faxitron HP). Plant were harvested 2 and 26 hours after irradiation, immediatly frozen and stored at -80°C until RNA extraction (Rneasy plant mini Kit, Qiagen) . Experiment was carried in duplicates and a non irradiated control was done for each time. 8 dye-swap - dose response,time course
Project description:Most studies have analysed the effects of high dose radiation such as atomic bomb survivors in Japan, people exposed during the Chernobyl nuclear accident, patients undergoing radiation therapy, uranium miners, etc. However, it has been difficult to measure and assess the risk of cancer in people exposed to lower doses of ionising radiation, such as the people living at high altitudes, who are exposed to more natural background radiation from cosmic rays than people at sea level. We measured the genomic response to X-ray ionising radiation (10 cGy and 100 cGy) in a skin tissue model to compare the effects of low and high dose ionising radiation at different time points. The microarray data was then analysed using state-of-the art “upside-down pyramid” computational systems biology methods to identify genes contributing to the difference in the response to the different radiation doses. The model is reconstructed skin tissue, which is composed of keratinocytes that make up the epidermal layer, and fibroblasts that make up the dermal layer of the skin. Tissues were irradiated with 0, 10, and 100 cGy X-ray radiation. Skin plugs were harvested at 0, 3, 8, and 24 hours post irradiation.
Project description:The current study analyzed the altered expression profiles of genes that are responsible for fluvastatin-induced breast cancer cell death in MDA-MB-231 cells (ER-ve basal breast cancer cells). Some of these altered gene expressions were further inter connceted to various pathways which may eventually be recognised as drug targets/ biomarkers in statin-sensitve breast cancer patients. To understand the differential gene expression profile in fluvastatin treated (24 h) malignant breast cancer cells with untreated malignant breast cancer cells.
Project description:The current study analyzed the metadherin (MTDH)-mediated altered gene expression profiles in ER negative MDA-MB-231 cells. Some of these altered gene expressions were further inter connected to various pathways which may eventually be recognized as drug targets or biomarkers in those breast cancers where MTDH plays a role in cancer progression/metastasis. To understand the global differential gene expression profile in MTDH-wild type and a newly identified MTDH-isoform knock down in metastatic breast cancer cells. This data was compared to untreated breast cancer cells.