The purpose of the present study was to investigate the association of glutathione S-transferase P1 (GSTP1) expression with resistance to neoadjuvant paclitaxel followed by 5-fluorouracil/epirubicin/cyclophosphamide (P-FEC) in human breast cancers. The relationship of GSTP1 expression and GSTP1 promoter hypermethylation with intrinsic subtypes was also investigated. In this study, primary breast cancer patients (n = 123, stage II-III) treated with neoadjuvant P-FEC were analyzed. Tumor samples were obtained by vacuum-assisted core biopsy before P-FEC. GSTP1 expression was determined using immunohistochemistry, GSTP1 promoter methylation index (MI) using bisulfite methylation assay and intrinsic subtypes using DNA microarray. The pathological complete response (pCR) rate was significantly higher in GSTP1-negative tumors (80.0%) than GSTP1-positive tumors (30.6%) (P = 0.009) among estrogen receptor (ER)-negative tumors but not among ER-positive tumors (P = 0.267). Multivariate analysis showed that GSTP1 was the only predictive factor for pCR (P = 0.013) among ER-negative tumors. Luminal A, luminal B and HER2-enriched tumors showed a significantly lower GSTP1 positivity than basal-like tumors (P = 0.002, P < 0.001 and P = 0.009, respectively), while luminal A, luminal B and HER2-enriched tumors showed a higher GSTP1 MI than basal-like tumors (P = 0.076, P < 0.001 and P < 0.001, respectively). In conclusion, these results suggest the possibility that GSTP1 expression can predict pathological response to P-FEC in ER-negative tumors but not in ER-positive tumors. Additionally, GSTP1 promoter hypermethylation might be implicated more importantly in the pathogenesis of luminal A, luminal B and HER2-enriched tumors than basal-like tumors.
GSTP1 expression predicts poor pathological complete response to neoadjuvant chemotherapy in ER-negative breast cancer.
Age, Specimen part, Disease stage
View SamplesAberrant 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.
Effects of genome architecture and epigenetic factors on susceptibility of promoter CpG islands to aberrant DNA methylation induction.
Cell line
View SamplesBackground. The in vivo distribution status and molecular signature of bone marrow mesenchymal stem cells (MSC) remain unknown, although ex vivo expanded MSC have been used in numerous studies.
Identification of mesenchymal stem cell (MSC)-transcription factors by microarray and knockdown analyses, and signature molecule-marked MSC in bone marrow by immunohistochemistry.
No sample metadata fields
View SamplesThere is a continuing need for driver strains to enable cell type-specific manipulation in the nervous system. Each cell type expresses a unique set of genes, and recapitulating expression of marker genes by BAC transgenesis or knock-in has generated useful transgenic mouse lines. However since genes are often expressed in many cell types, many of these lines have relatively broad expression patterns. We report an alternative transgenic approach capturing distal enhancers for more focused expression. We identified an enhancer trap probe often producing restricted reporter expression and developed efficient enhancer trap screening with the PiggyBac transposon. We established more than 200 lines and found many lines that label small subsets of neurons in brain substructures, including known and novel cell types. Images and other information about each line are available online (http://enhnacertrap.bio.brandeis.edu). Overall design: Examination of 6 cortical mouse neuronal cell types. 5 of which are in layer 6 in 3 different cortical regions.
A Mammalian enhancer trap resource for discovering and manipulating neuronal cell types.
Sex, Cell line, Subject
View SamplesInstructive mechanisms are present for induction of DNA methylation, as shown by methylation of specific CpG islands (CGIs) by specific inducers and in specific cancers. However, instructive factors involved are poorly understood, except for involvement of low transcription and trimethylation of histone H3 lysine 27 (H3K27me3). Here, we used methylated DNA immunoprecipitation (MeDIP) combined with a CGI oligonucleotide microarray analysis, and identified 5510 and 521 genes with promoter CGIs resistant and susceptible, respectively, to DNA methylation in prostate cancer cell lines. Expression analysis revealed that the susceptible genes had low transcription in a normal prostatic epithelial cell line. Chromatin immunoprecipitation with microarray hybridization (CHiP-chip) analysis of RNA polymerase II (Pol II) and histone modifications showed that, even among the genes with low transcription, the presence of Pol II was associated with marked resistance to DNA methylation (OR = 0.22; 95% CI = 0.12-0.38), and H3K27me3 was associated with increased susceptibility (OR = 11.20; 95% CI = 7.14-17.55). The same was true in normal human mammary epithelial cells for 5430 and 733 genes resistant and susceptible, respectively, to DNA methylation in breast cancer cell lines. These results showed that the presence of Pol II, active or stalled, and H3K27me3 can predict the epigenetic fate of promoter CGIs independently of transcription levels.
The presence of RNA polymerase II, active or stalled, predicts epigenetic fate of promoter CpG islands.
Cell line
View SamplesGIST is considered to invariably arise through gain-of-function KIT or PDGFRA mutation of the interstitial cells of Cajal (ICC). However, the genetic basis of the malignant progression of GIST is poorly understood.
Distinct gene expression-defined classes of gastrointestinal stromal tumor.
Sex, Age
View SamplesZinc-finger genes Fezf1 and Fezf2 encode transcriptional repressors. Fezf1 and Fezf2 are expressed in the early neural stem/progenitor cells and control neuronal differentiation in mouse dorsal telencephalon.
Zinc finger genes Fezf1 and Fezf2 control neuronal differentiation by repressing Hes5 expression in the forebrain.
Specimen part
View Samples7-days-old Arabidopsis seedlings of wildtype (Col-0) were treated with 1 M IAA for 15 minutes or 3 hours and gene expression of whole plant was analyzed using Affymetrix Gene 1.1 ST Array strips.
AtCAST3.0 update: a web-based tool for analysis of transcriptome data by searching similarities in gene expression profiles.
Age, Treatment, Time
View SamplesTranscriptional profiling of NKAES-derived NK cells after 7 days of culture compared to primary human NK cells and NK cells stimulated by low or high dose IL2 after 7 days of culture.
Expansion of highly cytotoxic human natural killer cells for cancer cell therapy.
Specimen part
View SamplesOur previous studies have revealed that treatment of pregnant rats with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, 1 g/kg) at gestational day (GD) 15 reduces the pituitary synthesis of luteinizing hormone (LH) during late fetal and early postnatal period, leading to imprinting of defects in sexual behaviors at adulthood. However, it remains obscure how the attenuation of pituitary LH links to sexual immaturity. To address this issue, we firstly performed a DNA microarray analysis to identify the gene(s) responsible for dioxin-induced sexual immaturity, using the pituitary and hypothalamus of male pups, at the age of postnatal day (PND)70, born from TCDD-treated dams. Among the reduced genes, we focused on gonadotropin-releasing hormone (GnRH) in the hypothalamus, because of its role in sexual behaviors suggested so far. The present study strongly suggests that maternal exposure to TCDD fixes the status of the lowered expression of GnRH in the offspring by reducing steroidogenesis at perinatal stage, and this is the mechanism for the imprinting of defects in sexual behaviors at adulthood.
Maternal exposure to dioxin imprints sexual immaturity of the pups through fixing the status of the reduced expression of hypothalamic gonadotropin-releasing hormone.
No sample metadata fields
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