Effects of long-term treatment with tamoxifen on endometrial gene expression in women.
ABSTRACT: The aim was to examine changes in gene expression of the endometrium exposed to long-term tamoxifen treatment in comparison to age matched controls. To achieve this, endometrial tissues were obtained from women receiving tamoxifen treatment who were undergoing a hysterectomy. Using cDNA microarrays, gene expression changes in the postmenopausal endometrium of these women was compared with that in endometrium of age matched women not receiving tamoxifen. Endometrial tissue from post-menopausal women was obtained following ethical approval from the Leicester NHS Trust. None of the women had received any hormonal treatment for two months prior to the procurement of the specimens. Tissues were taken from untreated women (n=6) or those treated for 4 to 5 years with tamoxifen (20mg/day) (n=4), aged 58-82 (65 ± 9.1, mean ± SD). Total RNA was extracted. Controls were pooled. RNA labelling, hybridisation and analysis of fluorescence was carried out as described by Turton et al (2001). Cy3/Cy5 Dye swap labelling was carried out on samples from each patient. Reference: Turton NJ et. al. (Oncogene (2001) 20, 1300-1306
Project description:Tamoxifen, a selective estrogen receptor modulator (SERM), is an effective treatment for breast cancers. In the CD-1 mouse model, neonatal oral dosing with tamoxifen leads to the development of adenomyosis. Both 4-hydroxyestradiol and tamoxifen can form DNA-reactive metabolites and may be involved in carcinogenesis of the uterus. After comparing the uterotrophic response of several SERMs the maximal uterotrophic doses of estradiol (100mg/kg) 4-hydroxyestradiol (385mg/kg) and tamoxifen (250mg/kg) were determined. Maximal uterotrophic doses were given orally to newborn CD-1 mice on days 1 – 4 after birth and gene and pathological changes examined in the uterus at 3 months after dosing. ERKOa knockout mice were dosed orally with tamoxifen (1mg/Kg) on days 1 – 4 after birth and uterine gene expression compared with CD-1 mice. Dosing groups: Estradiol (E2): 100mg/Kg 4-hydroxyestradiol (4OHE2): 385mg/Kg Tamoxifen : 250mg/Kg ERKO mice dosed with tamoxifen (1mg/Kg) 4 dosed animals and 4 controls for each treatment group. Uteri removed at 3 months after dosing and total RNA extracted. Controls were pooled. RNA labelling, hybridisation and analysis of fluorescence was carried out as described by Turton et al (2001). Cy3/Cy5 dye swap labelling was carried out on samples from each animal. Reference: Turton NJ et. al. (Oncogene (2001) 20, 1300-1306
Project description:Treatment with the breast cancer drug tamoxifen confers a risk of developing uterine tumors or other endometrial pathologies. Tamoxifen is a selective estrogen receptor modulator, which demonstrates tissue-specific activity although the mechanisms remain poorly understood. Both estradiol and tamoxifen act as estrogen agonists on the human uterus, and therefore have the potential to promote carcinogenicity. Estradiol and tamoxifen elicit cellular responses via the estrogen receptors (ER), which are involved in multiple signalling pathways. The effects at the molecular level are further influenced by the differential recruitment of co-factors and the presence of specific promoter motifs in target genes. In this study, ER positive (+) Ishikawa cells are used as a model to investigate the overall effect of treatment with either 17b-estradiol or 4-hydroxytamoxifen on the gene expression profiles. Ishikawa cells were serum-starved for 72 hours prior to treatment with 10-8M 17b-estradiol (E2) or 10-6M 4-hydroxytamoxifen (tam) for 24 or 48 hours. Cells were collected for total RNA extraction, and the quality and quantity of the RNA was determined spectrophotometrically. cDNA was prepared from treated (tam or E2) and control (vehicle only) Ishikawa cells, and was both forward and reverse labelled using Cy-3 dUTP/ Cy-5 dUTP and hybridised to oligo microarray slides representing >19,000 human genes (MRC HGMP-RFC). The data were analysed using GenePix Pro 3.0 software (Axon instruments) and statistical analyses applied to select significant gene changes (p<0.05).
Project description:RNA isolated from the 0, 10, 25, 50 and 100 micromolar AFB1 cultures at 120 min treatment was used for cDNA microarray experiments. For each array hybridization experiment, RNAs from the treated sample and its corresponding time-matched control were co-hybridized to arrays and respectively quantified in different channels. A dye swap strategy was used to eliminate the dye bias. Keywords: dose response
Project description:Identify genes with increased transcript abundance after low oxygen stress in Drosophila adults. There are 6 Oregon-R experiments comparing low oxygen exposed to normal oxygen. Samples 1-4 have hypoxic RNA labeled with cy5, and samples 5&6 are dye-swaps with the hypoxic RNA labeled with cy3. Samples 7&8 are Sb/Tm3 flies to control for background effects.
Project description:RNA isolated from the cultures treated with 0 and 50 micromolar AFB1 at 15, 30, 60, 90, 120 min was used for microarray experiments. For each array hybridization experiment, RNAs from the treated sample and its corresponding time-matched control were co-hybridized to arrays and respectively quantified in different channels. A dye swap strategy was used to eliminate the dye bias. Keywords: time-course
Project description:Chronic constant hypoxia (CCH), such as in pulmonary diseases or high altitude, and chronic intermittent hypoxia (CIH), such as in sleep apnea, can lead to major changes in the heart. The molecular mechanisms underlying these cardiac alterations are not well understood. We hypothesized that analysis on the changes in gene expression could help to delineate such mechanisms. In addition, the differences that can be anticipated between CCH and CIH could be potentially dissected. Current study used CCH and CIH mouse models combined with cDNA microarrays to determine the changes of gene expression in CCH or CIH mice heart. Keywords = heart Keywords = hypoxia Keywords = mouse Keywords = microarray Keywords: time-course