Project description:Neoadjuvant chemotherapy (NAC) is the major pre-treatment for breast cancer before surgery. Patients who achieve pathologic complete response (pCR) have a higher chance to receive lumpectomy and a better quality of life after neoadjuvant treatment. Luminal subtype breast cancer has poor NAC response compared with triple-negative breast cancer (TNBC) subtype. The molecular and cellular mechanisms underlying this chemoresistance are not fully understood. Here we report that the 17 featured transcriptional factors (TFs) in luminal and TNBC were identified. The association between 17 TFs and NAC pCR were analysis and exogenous luminal featured TF GATA3 overexpression promotes chemotherapy resistance in TNBC cell lines whereas its knockdown promotes sensitivity. In mechanism, we found that anthracycline based chemotherapy induces robust cellular ROS and Fe2+ overload in sensitivity cells; GATA3 mediates cell survival through repress CYB5R2 expression and Fenton reducing in DOX recycle which reduce cellular ROS and Fe2+ level during chemotherapy procedure. These founding altogether indicate that luminal featured transcription factor GATA3 enhance NAC resistance thorough repress ROS production and Fenton reducing. Breast cancer patient with GATA3 high expression might not suit for anthracycline based NAC regimen.
Project description:The transcription factor GATA3 is essential for luminal cell differentiation during mammary gland development and critical for formation of the luminal subtypes of breast cancer. Ectopic expression of GATA3 promoted global alterations of the transcriptome of basal triple-negative breast cancer cells resulting in molecular and cellular changes associated with a more differentiated, luminal tumor subtype and a concomitant reduction in primary tumor growth, lung metastasis, and macrophage recruitment at the metastatic site. Importantly, we demonstrate that the inhibition of metastases by GATA3 results from the suppression of lysyl oxidase (LOX) expression, a metastasis promoting matrix protein that affects cell proliferation, cross-linking of extracellular collagen types, and establishment of the metastatic niche. There are 2 samples sent in triplicates.
Project description:Background: The androgen receptor (AR) is a tumor suppressor in estrogen receptor (ER) positive breast cancer, a role sustained in some ER negative breast cancers. Key factors dictating AR genomic activity in a breast context are largely unknown. Herein, we employed an unbiased chromatin immunoprecipitation-based proteomic technique to identify endogenous AR interacting co-regulatory proteins in ER positive and negative models of breast cancer to gain new insight into mechanisms of AR signaling in this disease. Results: The DNA-binding factor GATA3 is identified and validated as a novel AR interacting protein in breast cancer cells irrespective of ER status. AR activation by the natural ligand 5α-dihydrotestosterone (DHT) increases nuclear AR-GATA3 interactions, resulting in AR-dependent enrichment of GATA3 chromatin binding at a sub-set of genomic loci. Silencing GATA3 reduces but does not prevent AR DNA binding and transactivation of genes associated with AR/GATA3 co-occupied loci, indicating a co-regulatory role for GATA3 in AR signaling. DHT-induced AR/GATA3 binding coincides with upregulation of luminal differentiation genes, including EHF and KDM4B, established master regulators of a breast epithelial cell lineage. These findings are validated in a patient-derived xenograft model of breast cancer. Interaction between AR and GATA3 is also associated with AR-mediated growth inhibition in ER positive and ER negative breast cancer.
Project description:The transcription factor GATA3 is essential for luminal cell differentiation during mammary gland development and critical for formation of the luminal subtypes of breast cancer. Ectopic expression of GATA3 promoted global alterations of the transcriptome of basal triple-negative breast cancer cells resulting in molecular and cellular changes associated with a more differentiated, luminal tumor subtype and a concomitant reduction in primary tumor growth, lung metastasis, and macrophage recruitment at the metastatic site. Importantly, we demonstrate that the inhibition of metastases by GATA3 results from the suppression of lysyl oxidase (LOX) expression, a metastasis promoting matrix protein that affects cell proliferation, cross-linking of extracellular collagen types, and establishment of the metastatic niche.
Project description:The GATA3 transcription factor is one of the most frequently mutated genes in breast cancer. Heterozygous mutations, largely frameshifting, are seen in 15% of estrogen receptor positive breast cancers, the subtype in which these mutations are almost exclusively found. Mouse studies have shown that Gata3 is critical for breast development and that GATA3 gene dosage affects breast tumor progression. Human patient data have shown that high Gata3 expression, a feature of luminal subtype breast cancers, is associated with a better prognosis. Although the frequency of GATA3 mutation suggests an important role in breast cancer development or progression, there is little understanding of how mutations in GATA3 affect its function in luminal breast epithelial cells and what gene expression changes result as a consequence of the mutations. Here, using gene editing, we have created two sets of isogenic human luminal breast cancer cell lines with and without a truncating GATA3 mutation. GATA3 mutation enhanced tumor growth in vivo but did not affect sensitivity to clinically used hormonal therapies or chemotherapeutic agents. We identified genes upregulated and downregulated in GATA3 mutant cells, a subset of which was concordantly differentially expressed in GATA3 mutant primary luminal breast cancers. Addback of mutant GATA3 recapitulated mutation-specific gene expression changes and enhanced soft agar colony formation, suggesting a gain of function for the mutant protein.
Project description:Pioneer transcription factors bind to silent chromatin, and initiate cell fate conversion. One potential pioneer factor, GATA3, is a critical component for multiple cellular programs. GATA3 is of particular interest as it regulates gene expression in breast cancers, and low expression correlates with poor prognosis. Here we demonstrate the pioneering activity of GATA3 utilizing a cellular reprogramming system (the mesenchymal-epithelial transition) in breast cancer cells. During the epithelial transition, GATA3 catalyzes chromatin reprogramming by inducing chromatin opening, active enhancer modifications, and nucleosome remodelling. We determined that the transactivation domain is required for this chromatin reprogramming. Importantly, a mutant lacking the transactivation domain possessed the chromatin binding ability but failed to create open chromatin, suggesting binding alone is not sufficient to induce open chromatin. These data illustrate a fundamental mechanism of GATA3-mediated gene regulation, and provide evidence for a pre-engagement state of closed chromatin bound by a pioneer factor.
Project description:GATA3 is one of the most frequently mutated genes in breast cancer. The roles of GATA3 mutations remain elusive. In this study, we characterized newly established luminal breast cancer cell lines that stably express different GATA3 patient-derived mutants (Splice site deletion, C321 frame-shift, and A333 frame-shift mutants). The expression of these mutants lead to altered expression of EMT related genes as well as redistribution of GATA3.
Project description:The study was designed to evaluate the transcriptional effects of ectopic expression of mutant GATA3 proteins in a breast cancer cell line. Wild-type GATA3 is included as a control. The mutations are a stop codon at position 308 and a frameshift at position 335.
Project description:The transcription factor GATA3 is a favorable prognostic indicator in estrogen receptor-M-NM-1 (ERM-NM-1)-positive breast tumors in which it participates with ERa and FOXA1 in a complex transcriptional regulatory program driving tumor growth. Paradoxically, GATA3 mutations are frequent in breast cancer and have been classified as drivers. To elucidate the contribution(s) of GATA3 alterations to oncogenesis, we studied two breast cancer cell lines, MCF7, which carries a heterozygous frameshift mutation in the second zinc finger of GATA3, and T47D, wild-type at this locus. Heterozygosity for the truncating mutation conferred protection from regulated turnover of GATA3, ERa and FOXA1 following estrogen stimulation. Thus, mutant GATA3 uncouples protein-level regulation of master regulatory transcription factors from hormone action. Consistent with increased protein stability, ChIP-seq profiling identified stronger accumulation of GATA3 in cells bearing the mutation, albeit with a similar distribution across the genome. We propose that this specific, cancer-derived mutation in GATA3 deregulates physiologic protein turnover, stabilizes GATA3 binding across the genome and modulates the response of mammary epithelial cells to hormone signaling, thus conferring a selective growth advantage. Genome-wide mapping of GATA3 in two cell lines. There were two biological replicates and unchipped (input) DNA was used as reference.
Project description:A pioneer transcription factor, GATA3, is one of the most frequently mutated genes in breast cancer, yet the impact of these mutations is largely unknown. We generated a GATA3 mutant cell line (T47D wt/R330fs) by CRISPR. Mutation of one allele of GATA3 led to loss of binding and decreased expression at a subset of genes, including Progesterone Receptor. At other loci, associated with epithelial to mesenchymal transition, gain of binding at a novel sequence motif correlated with increased gene expression. Our results illuminate tumor-promoting functions of specific GATA3 mutations in breast cancer.