Epigenome analysis of normal breast samples
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE101961 | GEO | 2017/07/28
SECONDARY ACCESSION(S): PRJNA396020
REPOSITORIES: GEO
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Project description:Despite known age-related DNA methylation (aDNAm) changes in breast tumors, little is known about aDNAm in normal breast tissues. Breast tissues from a cross-sectional study of 121 cancer-free women, were assayed for genome-wide DNA methylation. mRNA expression was assayed by microarray technology. Analysis of covariance was used to identify aDNAm’s. Altered methylation was correlated with expression of the corresponding gene and with DNA methyltransferase protein DNMT3A, assayed by immunohistochemistry. Publically-available TCGA data were used for replication. 1,214 aDNAm’s were identified; 97% with increased methylation, and all on autosomes. Sites with increased methylation were predominantly in CpG lslands and non-enhancers. aDNAm’s with decreased methylation were generally located in intergenic regions, non-CpG Islands, and enhancers. Of the aDNAm’s identified, 650 are known to be involved in cancer, including ESR1 and beta-estradiol responsive genes. Expression of DNMT3A was positively associated with age. Two aDNAm’s showed significant associations with DNMT3A expression; KRR1 (OR 6.57, 95% CI: 2.51-17.23) and DHRS12 (OR 6.08, 95% CI: 2.33-15.86). A subset of aDNAm’s co-localized within vulnerable regions for somatic mutations in breast cancer. Expression of C19orf48 was inversely and significantly correlated with its methylation level. In the TCGA dataset, 84% and 64% of the previously identified aDNAm’s were correlated with age in both normal-adjacent and tumor breast tissues, with differential associations by histological subtype. Given the similarity of findings in the breast tissues of healthy women and breast tumors, and the effects on gene expression, aDNAm’s may be one pathway for increased breast cancer risk with age. Obesity is a risk factor for breast cancer, but the underlying mechanisms for this are only partially understood, and there has been only limited study of breast tissues molecularly before cancer develops. Breast tissues from healthy women undergoing reduction mammoplasty and epidemiologic interviews (n=121) were profiled for the whole genome transcriptome (Affymetrix Human Transcriptome Arrays) and genome-wide DNA methylation (Infinium HumanMethylation 450 BeadChip array). After adjusting for confounding by age and race, 12,210 CpG dinucleotides with altered methylation levels correlated with body mass index (BMI) (10,808 positive correlations and1,402 negative correlations, FDR<0.05). Among them 4,170 BMI-associated hypermethylated CpG dinucleotides (-1.5 kb from transcription start site, 1st Exon, and 5’UTR) and 443 BMI-associated hypomethylated CpG dinucleotides were located in promoter regions. By integrating DNA methylation and mRNA expression data, we identified 310 methylated genes that correlated with gene expression (FDR<0.05). Of these, 242 genes had higher methylation status showing concurrent down-regulation in obese women, and 68 genes had lower methylation status showing concurrent up-regulation in obese women. Among the affected genes involved in diseases and disorders for inflammatory response, hereditary disorder, and immunological disease. This study provides evidence that obesity epigenetically deregulates genes potentially involved in breast cancer that have functional relationships to gene expression.
2017-08-01 | GSE102088 | GEO
Project description:Purpose: Black/African American (AA) women are twice as likely to be diagnosed with triple negative breast cancer (TNBC) compared to whites, an aggressive breast cancer subtype associated with poor prognosis. There are no routinely used targeted clinical therapies for TNBC; thus there is a clear need to identify prognostic markers and potential therapeutic targets. Methods: We evaluated expression of 27,016 genes in 155 treatment-naïve TN tumors from AA women in Detroit. Associations with survival were evaluated using Cox proportional hazards models adjusting for stage and age at diagnosis, and p-values were corrected using a false discovery rate. Our validation sample consisted of 158 TN tumors (54 AA) from The Cancer Genome Atlas (TCGA). Meta-analyses were performed to obtain summary estimates by combining TCGA and Detroit AA cohort results. Results: In the Detroit AA cohort, CLCA2 [Hazard ratio (HR)=1.56, 95% confidence interval (CI) 1.31-1.86, nominal p=5.1x10-7, FDR p=0.014], SPIC [HR=1.47, 95%CI 1.26-1.73, nominal p=1.8x10-6, FDR p=0.022], and MIR4311 [HR=1.57, 95% CI 1.31-1.92, nominal p=2.5x10-5, FDR p=0.022] expression were associated with overall survival. Further adjustment for treatment and breast cancer specific survival analysis did not substantially alter effect estimates. Meta-analysis with TCGA data showed that CLCA2 and SPIC were associated with overall survival for TNBC among AA women. Conclusions: We identified three potential prognostic markers for TNBC in AA women, for which SPIC may be an AA-specific prognostic marker.
2019-12-17 | GSE142102 | GEO
Project description:Aberrant DNA methylation is induced at specific promoter CpG islands (CGIs) in contrast with mutations. The specificity is influenced by genome architecture and epigenetic factors, but their relationship is still unknown. In this study, we isolated promoter CGIs susceptible and resistant to aberrant methylation induction during prostate and breast carcinogenesis. The effect of genome architecture was more evident for promoter CGIs susceptible in both of the two tissues than for promoter CGIs susceptible only in one tissue. Multivariate analysis of promoter CGIs with tissue-nonspecific susceptibility showed that genome architecture, namely a remote location from SINE (OR=5.98; 95% CI=2.33-15.34) and from LINE (OR=2.08; 95% CI=1.03-4.21), was associated with increased susceptibility, independent of epigenetic factors such as the presence of RNA polymerase II (OR=0.09; 95% CI=0.02-0.48) and H3K27me3 (OR=3.28; 95% CI=1.17-9.21). These results showed that methylation susceptibility of promoter CGIs is determined both by genome architecture and epigenetic factors, independently.
2011-06-06 | GSE28284 | GEO
Project description:Calorie restriction has long been known to extend lifespans and inhibit carcinogenesis in multiple species by slowing age-related epigenetic changes while the underlying mechanisms remain largely unknown. Herein, we found that starvation activated autophagy to remodel DNA methylation profile by inhibiting DNMT3a expression. Autophagy is impaired in chemoresistance which was associated with differential DNA methylation and could be reversed by DNMT3a inhibition. Autophagy activation decreases the expression of DNMT3a mRNA, accompanied with the downregulation of chemoresistance-related Linc00942. Knockdown of Linc00942 reduces DNMT3a expression and genome-wide DNA methylation while Linc00942 overexpression increased DNMT3a expression and correlated hypermethylation in cancer cells and primary tumor tissues. As a result, inhibition of autophagy increases Linc00942 expression to promote chemoresistance and autophagy activation or hypomethylating agent decitabine restores chemosensitivity by reducing global DNA methylation.
2023-08-08 | GSE210596 | GEO
Project description:Extracellular, cancer-specific methylated DNA has been shown to be a prognostic marker when detected in serum or plasma. In this study we investigated the effect of treating cancer cells with differentially methylated CpG DNA. When breast cancer cell lines were treated with methylated CpG DNA, a consistent upregulation of CHAC1 mRNA expression was observed. CHAC1 was recently described to be a novel component of the unfolded protein response pathway. To elucidate the role of CHAC1 mRNA expression in cancer in more detail, we analyzed expression of this gene in breast (n=107) and ovarian cancer (n=107) and found a strong correlation with tumor differentiation. Poorly differentiated tumors exhibited higher CHAC1 expression levels (p=0.004 for breast and p=0.031 for ovarian cancer). Additionally, hormone receptor (HR)-negative breast cancers (p<0.001) and advanced stage disease ovarian cancers (p=0.026) also demonstrated high CHAC1 mRNA levels. mRNA expression analysis of the two known CHAC1 isoforms showed a strong association of expression above the median with poor outcome in breast cancer patients in a multivariate analysis (isoform a: relative risk (RR) of death 3.2 (95% CI 1.6-6.5; p<0.01); RR of relapse 3.9 (95% CI 1.6-9.8; p<0.01); isoform b: relative risk (RR) of death 3.5 (95% CI 1.6-7.3; p<0.01); RR of relapse 6.6 (95% CI 2.4-18.5; p<0.01)). Univariate analysis in ovarian cancer showed that CHAC1 mRNA expression above the median was associated with a poor relapse free survival (p=0.03). In younger ovarian cancer patients (age < median age), a high CHAC1 mRNA expression was associated with overall survival (p=0.007) and relapse free survival (p=0.015). Finally, we show that downregulation of CHAC1 by small interfering RNA suppressed breast cancer cell migration and proliferation, whereas overexpression resulted in an observed increase in these cellular behaviours. This is the first report demonstrating that a gene (CHAC1) whose expression is triggered by methylated, but not unmethylated DNA, is involved in tumour biology. Human breast cancer cell lines (BT-20, Hs578T) were treated with methylated and unmethylated DNA oligos, and differentially expressed genes were identified between treatments with methylated and un-methylated oligos.
2011-12-01 | E-GEOD-22865 | biostudies-arrayexpress
Project description:Inactivating germline BRCA1 and BRCA2 mutations confer a defect in homologous recombination DNA repair which was found to leave traces in tumor DNA copy number aberration (CNA) profiles. In analogy to previously trained breast cancer CNA classifiers that predicted association with BRCA1 and BRCA2 mutated cancer and benefit of high dose double strand break inducing chemotherapy, we trained BRCA1 and BRCA2 classifiers on CNA profiles of 50 BRCA1 mutated, 10 BRCA2 mutated and 13 non-familial ovarian cancers and investigated whether tumor type and mutation type independent classifiers could be trained. The cross validated area under the curve of the receiver/operator characteristic curve of ovarian cancer BRCA1 and BRCA2 classifiers were 0.67 (95% CI: 0.55-0.78) and 0.91 (95% CI: 0.79-1). These classifiers identified the majority of the samples with germline and somatic BRCA1 and BRCA2 mutations and BRCA1 promoter hypermethylation in the Cancer Genome Atlas (TCGA) dataset. Combining tumor type or mutated gene did not yield higher AUCs than single gene classifiers, although the ovarian BRCA1+BRCA2 classifier identified most BRCA1 and -2 mutated cases, including those in the TCGA dataset, and a combined breast and ovarian cancer BRCA1 classifier may improve response prediction to double strand break inducing chemotherapy.
2021-12-31 | GSE111688 | GEO
Project description:Calorie restriction has long been known to extend lifespans and inhibit carcinogenesis in multiple species by slowing age-related epigenetic changes while the underlying mechanisms remain largely unknown. Herein, we found that starvation activated autophagy to remodel DNA methylation profile by inhibiting DNMT3a expression. Autophagy is impaired in chemoresistance which was associated with differential DNA methylation and could be reversed by DNMT3a inhibition. Autophagy activation decreases the expression of DNMT3a mRNA, accompanied with the downregulation of chemoresistance-related Linc00942. Knockdown of Linc00942 reduces DNMT3a expression and genome-wide DNA methylation while Linc00942 overexpression increased DNMT3a expression and correlated hypermethylation in cancer cells and primary tumor tissues. As a result, inhibition of autophagy increases Linc00942 expression to promote chemoresistance and autophagy activation or hypomethylating agent decitabine restores chemosensitivity by reducing global DNA methylation. Taken together, our study identifies a novel methylation cascade linking impaired RNautophagy to global hypermethylation in chemoresistance, and provides a rationale for repurposing decitabine to overcome chemoresistance in cancer treatment.
2023-09-12 | GSE212184 | GEO
Project description:Extracellular, cancer-specific methylated DNA has been shown to be a prognostic marker when detected in serum or plasma. In this study we investigated the effect of treating cancer cells with differentially methylated CpG DNA. When breast cancer cell lines were treated with methylated CpG DNA, a consistent upregulation of CHAC1 mRNA expression was observed. CHAC1 was recently described to be a novel component of the unfolded protein response pathway. To elucidate the role of CHAC1 mRNA expression in cancer in more detail, we analyzed expression of this gene in breast (n=107) and ovarian cancer (n=107) and found a strong correlation with tumor differentiation. Poorly differentiated tumors exhibited higher CHAC1 expression levels (p=0.004 for breast and p=0.031 for ovarian cancer). Additionally, hormone receptor (HR)-negative breast cancers (p<0.001) and advanced stage disease ovarian cancers (p=0.026) also demonstrated high CHAC1 mRNA levels. mRNA expression analysis of the two known CHAC1 isoforms showed a strong association of expression above the median with poor outcome in breast cancer patients in a multivariate analysis (isoform a: relative risk (RR) of death 3.2 (95% CI 1.6-6.5; p<0.01); RR of relapse 3.9 (95% CI 1.6-9.8; p<0.01); isoform b: relative risk (RR) of death 3.5 (95% CI 1.6-7.3; p<0.01); RR of relapse 6.6 (95% CI 2.4-18.5; p<0.01)). Univariate analysis in ovarian cancer showed that CHAC1 mRNA expression above the median was associated with a poor relapse free survival (p=0.03). In younger ovarian cancer patients (age < median age), a high CHAC1 mRNA expression was associated with overall survival (p=0.007) and relapse free survival (p=0.015). Finally, we show that downregulation of CHAC1 by small interfering RNA suppressed breast cancer cell migration and proliferation, whereas overexpression resulted in an observed increase in these cellular behaviours. This is the first report demonstrating that a gene (CHAC1) whose expression is triggered by methylated, but not unmethylated DNA, is involved in tumour biology.
2011-12-01 | GSE22865 | GEO
Project description:Introduction: A gene expression signature indicative of active wound responses is common to more than 90% of non-neoplastic tissues adjacent to breast cancer, but these tissues also show substantial heterogeneity, suggesting different microenvironmental subtypes. Genomic variation in the extratumoral microenvironment has received limited study. Methods: Gene expression analysis from 72 patient-derived samples adjacent to invasive breast cancer or ductal carcinoma in situ was evaluated. Unsupervised clustering identified two distinct gene expression subgroups that differed substantially in expression of genes associated with epithelial-to-mesenchymal transition (EMT). We evaluated the prognostic and biological relevance of this extratumoral EMT-like signature using clinical and experimental approaches. Results: We found that the extratumoral EMT-like signature was not significantly associated with overall survival among all patients [Hazard Ratio (HR) = 1.4, 95% CI 0.6 - 2.8, p=0.337], but there was a strong association with overall survival among estrogen receptor (ER)-positive patients [HR = 2.5, 95% CI 0.9 – 6.7, p=0.062] or hormone-treated patients [HR=2.6, 95% CI 1.0 – 7.0, p=0.045]. In addition, co-culturing of ER-positive MCF-7 cells with cells undergoing EMT increased migration of MCF7 cells in a TGF-β1 dependent manner. Conclusion: Together, these results suggest that the presence of an EMT-like signature in the cancer-adjacent extratumoral microenvironment may influence the aggressiveness of the ER-positive tumors and that ER-positive patients with these extratumoral signatures may require additional treatments or more aggressive surgeries. Reference vs. test sample. 74 test samples (12 breast tumors, 62 normal tissue adjacent to breast tumor) from 72 patients.
2011-12-31 | E-GEOD-31589 | biostudies-arrayexpress
Project description:Background: Low socioeconomic status (SES) has been linked to chronic stress and poorer health outcomes for marginalized communities in the U.S. The biological processes mediating the impact of SES on health to promote chronic diseases, such as cancer, remain poorly understood. Here, we aim to determine how changes in DNA methylation are linked to neighborhood-level socioeconomic deprivation, thereby promoting cancer initiation and progression through cancer- and immune-related pathways. Methods: We extracted DNA from 402 fresh frozen tissues from 289 women in the NCI-Maryland Breast Cancer Cohort, including 185 tumor samples, 113 additional paired adjacent normal samples, and 104 normal tissues from reduction mammoplasty. Census-tract level socioeconomic deprivation was measured via a Neighborhood Deprivation Index (NDI) using the geocoded addresses from our study participants. DNA methylation values were acquired using the Illumina Infinium MethylationEPIC 850K Beadchip. We conducted a differentially methylated probe (DMP) analysis between tumor and adjacent normal tissue to characterize methylation profiles by NDI status. We also used methylCIBERSORT to estimate immune cell subpopulation differences by tissue type and NDI status. Results: NDI was significantly associated with self-reported race in our cohort in both normal (p<0.0001, 95% CI -4.32, -2.58) and tumor (p<0.0001, 95% CI -4.22, -2.79) tissue. Our DMP analysis showed more significant methylation events (hypo- or hyper- methylation of the tumor tissue compared to adjacent normal tissue) in the NDI high group compared to the NDI low group. We also identified five CpG sites that were significantly hypomethylated in the tumors of the NDI high group, including two tumor suppressor genes, LRIG1 (p=1.99 x10-10) and WWOX (p=6.47 x 10-9). These methylation changes translated to an inverse relationship between gene expression for these tumor suppressor genes and NDI. We also identified significantly lower neutrophils in the NDI high tumors compared to NDI low tumors (p=0.001, 95% CI -0.112, -0.028). Conclusions: Overall, our analysis provides evidence that high neighborhood deprivation can lead to pro-tumorigenic changes in DNA methylation and gene expression that may impact the immune microenvironment, breast cancer progression, and overall survival.
2023-10-15 | GSE225845 | GEO