Project description:We are using the ACI rat model of 17beta-estradiol induced mammary cancer to define the mechanisms through which estrogens contribute to breast cancer development; identify and functionally characterize the genetic variants that determine susceptibility; and define the hormone-gene-environment interactions that influence development of mammary cancer in this physiologically relevant rat model. Female ACI rats are uniquely susceptible to development of mammary cancer when treated continuously with physiologic levels of 17beta-estradiol. Induction of mammary cancer in female ACI rats occurs through a mechanism that is largely dependent upon estrogen receptor-alpha. Interval mapping analyses of progeny generated in intercrosses between susceptible ACI rats and resistant Brown Norway (BN) rats revealed seven quantitative trait loci (QTL), designated Emca3 (Estrogen-induced mammary cancer) through Emca9, each of which harbors one or more genetic determinants of mammary cancer susceptibility. Genes that reside within Emca8 on RNO5 and were differentially expressed between 17beta-estradiol treated ACI and ACI.BN-Emca8 congenic rats were identified as Emca8 candidates. Two groups of 17beta-estradiol treated female rats were compared. Five ACI and five BN.ACI-Emca8 rats were treated with 17beta-estradiol for 12 weeks. Total RNA was isolated from the mammary glands of these animals, labeled, and hybridized to Affymetrix Rat Genome 230 2.0 Arrays (Affymetrix Inc.). Significantly differentially expressed genes were found between these groups.
Project description:Maternal exposures during pregnancy influence the risk of many chronic adult-onset diseases in the offspring. We investigated whether feeding pregnant rats a high fat (HF) or ethinyl-estradiol (EE2)-supplemented diet affects carcinogen-induced mammary cancer risk in daughters, granddaughters and great-granddaughters. Here we show that mammary tumorigenesis is higher in daughters and granddaughters of HF rat dams and in daughters, granddaughters and great-granddaughters of EE2 rat dams. Outcross experiments indicate that increased mammary cancer risk is transmitted to HF granddaughters equally through the female or male germlines, but it is only transmitted to EE2 granddaughters through the female germline. The effects of maternal EE2 exposure on offspring's mammary cancer risk are associated with alternations in the DNA methylation machinery and methylation patterns in mammary tissue of all three EE2 generations. We conclude that dietary and estrogenic exposures in pregnancy increase breast cancer risk in multiple generations of offspring, possibly through non-genetic means
Project description:Maternal exposures during pregnancy influence the risk of many chronic adult-onset diseases in the offspring. We investigated whether feeding pregnant rats a high fat (HF) or ethinyl-estradiol (EE2)-supplemented diet affects carcinogen-induced mammary cancer risk in daughters, granddaughters and great-granddaughters. Here we show that mammary tumorigenesis is higher in daughters and granddaughters of HF rat dams and in daughters, granddaughters and great-granddaughters of EE2 rat dams. Outcross experiments indicate that increased mammary cancer risk is transmitted to HF granddaughters equally through the female or male germlines, but it is only transmitted to EE2 granddaughters through the female germline. The effects of maternal EE2 exposure on offspring's mammary cancer risk are associated with alternations in the DNA methylation machinery and methylation patterns in mammary tissue of all three EE2 generations. We conclude that dietary and estrogenic exposures in pregnancy increase breast cancer risk in multiple generations of offspring, possibly through non-genetic means We examined the whole genome methylation status of both control and EE2-supplemented diet rats in three consecutive generations
Project description:Mammary Gland Morphology and Gene Expression Signature of Prepubertal Male and Female Rats Following Exposure to Exogenous Estradiol
Project description:We are using the ACI rat model of 17beta-estradiol induced mammary cancer to define the mechanisms through which estrogens contribute to breast cancer development; identify and functionally characterize the genetic variants that determine susceptibility; and define the hormone-gene-environment interactions that influence development of mammary cancer in this physiologically relevant rat model. Female ACI rats are uniquely susceptible to development of mammary cancer when treated continuously with physiologic levels of 17beta-estradiol. Induction of mammary cancer in female ACI rats occurs through a mechanism that is largely dependent upon estrogen receptor-alpha. Interval mapping analyses of progeny generated in intercrosses between susceptible ACI rats and resistant Brown Norway (BN) rats revealed seven quantitative trait loci (QTL), designated Emca3 (Estrogen-induced mammary cancer) through Emca9, each of which harbors one or more genetic determinants of mammary cancer susceptibility. Genes that reside within Emca8 on RNO5 and were differentially expressed between 17beta-estradiol treated ACI and ACI.BN-Emca8 congenic rats were identified as Emca8 candidates.
Project description:We are using ACI and BN rats, which differ markedly in their susceptibility to 17beta-Estradiol (E2)-induced mammary cancer, to identify genetic variants and environmental factors that determine mammary cancer susceptibility. The objective of this study was to characterize the cellular and molecular responses to E2 in the mammary glands of ACI and BN rats to identify qualitative and quantitative phenotypes that associate with and/or may confer differences in susceptibility to mammary cancer. Female ACI and BN rats were treated with E2 for 1, 3 or 12 weeks and cell proliferation, apoptosis, differentiation and gene expression were evaluated. The luminal epithelium of ACI rats exhibited a rapid and sustained proliferative response to E2. By contrast, the proliferative response exhibited by the mammary epithelium of BN rats was restrained and transitory. Moreover, the epithelium of BN rats appeared to undergo differentiation in response to E2, as evidenced by production of milk proteins as well as luminal ectasia and associated changes in the extracellular matrix (ECM). Marked differences in expression of genes that encode proteins with well-defined roles in mammary gland development (Pgr, Wnt4, Tnfsf11, Prlr, Stat5a, Areg, Gata3), differentiation and milk production (Lcn2, Spp1), regulation of extracellular environment (Mmp7, Mmp9), and cell-cell or cell-ECM interactions (Cd44, Cd24, Cd52) were observed. We propose that these cellular and molecular phenotypes are heritable and may underlie, at least in part, the differences in mammary cancer susceptibility exhibited by ACI and BN rats. Two groups of 17beta-estradiol treated female rats were compared. Five ACI and five BN rats were treated with 17beta-estradiol for 12 weeks. Total RNA was isolated from the mammary glands of these animals, labeled, and hybridized to Affymetrix Rat Genome 230 2.0 Arrays (Affymetrix Inc.). Significantly differentially expressed genes were found between these groups.
Project description:RON WT and RON KO at 5, 6, 7 week virgin mammary glands In the study, we demonstrated that RON regulates mammary gland branching morphogenesis in pubertal development associated with changes in gene expression. Keywords: Pubertal mammary glands In the study, we hybridized RNA from 5, 6, 7 week old virgin female RON WT and KO mammary glands to Affymetrix GeneChip Mouse Genome 430 2.0 Array
Project description:Human studies suggest that high-fat diets (HFD) increase the risk of breast cancer. The 7,12 dimethylbenz[a]anthracene (DMBA)-induced mammary carcinogenesis rat model is commonly used to evaluate the effects of lifestyle factors such as HFD on mammary-tumor risk. Past studies focused primarily on the effects of continuous maternal exposure on the risk of offspring at the end of puberty (PND50). We assessed the effects of prenatal HFD exposure on cancer susceptibility in prepubertal mammary glands and identified key gene networks associated with such disruption. During pregnancy, dams were fed AIN93G-based diets with high (39% Kcal) olive oil, butterfat, or safflower oil. The control group received AIN-93G with 10% Kcal soy oil. Female offspring were treated with DMBA on PND21. However, a significant increase in tumor volume and a trend of shortened tumor latency were observed in rates with HFD exposure against the controls (p=0.067 and 0.048 respectively). Large-volume tumors harbored carcinoma in situ. Transcriptome profiling identified 43 differentially expressed genes in the mammary glands of the HFD group as compared with control. Rapid hormone signaling was the most dysregulated pathway. The diet also induced aberrant expression of Dnmt3a, Mbd1, and Mbd3, suggesting potential epigenetic disruption. Collectively, these findings provide the first evidence supporting susceptibility of prepubertal mammary glands to DMBA-induced tumorigenesis that can be modulated by dietary fat that involves aberrant gene expression and epigenetic dysregulation.
Project description:In order to properly understand whether xenoestrogens act as estrogens, it is essential to possess a solid portrait of the physiological effects of exogenous estradiol. Because the estrogen-dependent gene expression is one of the primary biomarkers of estrogenic action, we have assessed effects of three doses of exogenous estradiol (0.1, 1.0 and 10 ug/kg of body weight/day) on the mammary gland morphology and gene expression profiles by microarray analysis of prepubertal male and female rats of both sexes compared to untreated controls. Estradiol was administered subcutaneously with minipumps from weaning at PND21 to the end of the experiment at PND33. The data suggest that the male mammary is a sensitive tissue for estrogenicity assessment. Groups of male and female rats were infused subcutaneously with mini-osmotic pumps with 17-beta-estradiol from weaning on post-natal day (PND) 21 until PND 33. Pumps delivered doses of 0, 0.1, 1.0 and 10 ug/kg/d. At sacrifice (PND 33) abdominal mammary gland pairs were collected and fresh frozen in liquid nitrogen.
Project description:In order to properly understand whether xenoestrogens act as estrogens, it is essential to possess a solid portrait of the physiological effects of exogenous estradiol. Because the estrogen-dependent gene expression is one of the primary biomarkers of estrogenic action, we have assessed effects of three doses of exogenous estradiol (0.1, 1.0 and 10 µg/kg of body weight/day) on the mammary gland morphology and gene expression profiles by microarray analysis of prepubertal male and female rats of both sexes compared to untreated controls. Estradiol was administered subcutaneously with minipumps from weaning at PND21 to the end of the experiment at PND33. The data suggest that the male mammary is a sensitive tissue for estrogenicity assessment.