Project description:LSD1 (KDM1A) is a histone demethylase that plays both oncogenic and tumor suppressor roles in breast cancer. However, the exact contexts under which it plays these opposite roles remain largely elusive. By characterizing its role in normal and cancerous luminal mammary epithelial cells (MECs), here we show that LSD1 is essential for maintaining differentiation and survival of luminal cells. LSD1-inhibition by both genetic and pharmacological approaches increases invasion of luminal breast cancer cells. Mechanistically, we find LSD1 interacts with GATA3 and their common target genes are highly related to breast cancer. LSD1 positively regulates GATA3 expression and represses that of TRIM37, a histone H2A ubiquitin ligase and breast cancer oncoprotein. LSD1-loss leads to reduced expression of several cell junction genes (e.g., CDH1, VCL, CTNNA1), possibly via TRIM37-mediated repression. Collectively, our data suggest LSD1 largely plays a tumor suppressor role in luminal breast cancer and the increased MEC invasiveness associated with LSD1-inhibition can be blocked via TRIM37-inhibition.
Project description:The origin of breast cancer, whether primary or recurrent,is unknown. Here, we show that invasive breast cancer cells under conditions of hypoxia release small extracellular vesicles (sEV) that disrupt the differentiation hierarchy of the normal mammary epithelium, expand stem and luminal progenitor cells, and induce atypical ductal hyperplasia, cellular proliferation, and intraepithelial neoplasia. This is accompanied by systemic immunosuppression with increased myeloid cell release of the “alarmin”, S100A9, and multiple oncogenic traits of EMT, sustained angiogenesis, and local and disseminated luminal cell invasion, in vivo. When applied on the genetic background of a driver oncogene (MMTV-PyMT), hypoxic sEV accelerate bilateral breast cancer onset and progression. Mechanistically, genetic or pharmacologic targeting of hypoxia-inducible factor-1 (HIF1) packaged in hypoxic sEV or homozygous deletion of S100A9 normalizes mammary gland differentiation, restores T cell function and prevents atypical hyperplasia. The transcriptome of sEV-induced mammary gland lesions resembles luminal breast cancer, and detection of HIF1 in plasma circulating sEV from luminal breast cancer patients correlates with clinical recurrence. Therefore, a pleiotropic sEV-HIF1 signaling axis drives local and systemic mechanisms of mammary gland transformation at high risk for full-blown, multifocal breast cancer. This pathway may provide a readily accessible biomarker of luminal breast cancer progression.
Project description:Rank signaling regulates mammary gland development and epithelial cell differentiation. Rank receptor is expressed by mammary basal and luminal populations, but unlike that of luminal, the contribution of basal Rank signaling to mammary gland homeostasis remains poorly studied. Combining timely-regulated, basal-specific Rank expression with lineage tracing strategies we unveiled that Rank signaling controls basal cell identity in postnatal mammary glands. Enhanced basal Rank disrupts basal and luminal cell identity, resulting in aberrant luminal-like differentiation of basal cells, defective lactation and the appearance of premalignant lesions composed of a basal-derived hybrid population with luminal/alveolar features, which ultimately generates basal and luminal breast adenocarcinomas. Mechanistically, phospho-proteomic, transcriptomic and chromatin analyses support that basal Rank activation triggers the loss of tumor suppressive epigenetic regulators, leading to chromatin remodeling, disruption of basal identity and tumorigenesis. We uncover a basal Rank gene signature that can be predictive of progression from in situ to invasive adenocarcinomas and associates with poor prognosis in breast cancer patients, particularly in those diagnosed with luminal adenocarcinomas, underlining the clinical relevance of our findings. Our results reinforce the idea that basal lineage infidelity triggered by Rank signaling contribute to generation from pre-invasive lesions and transition to invasive breast cancer.
Project description:Transcription factor GATA3 is essential for the specification and maintenance of the luminal cell differentiation in the mammary gland, and its expression is progressively lost during luminal breast cancer progression. However, how loss-of-function of GATA3 contributes to the development of breast cancer is still poorly understood. Here, we report that GATA3 nucleates a transcription repression program composed of G9A and MTA3-, but not MTA1- or MTA2-, constituted NuRD complex. Genome-wide analysis of the GATA3/G9A/NuRD(MTA3) targets identified a cohort of genes that are critically involved in epithelial-to-mesenchymal transition and cell invasion.
Project description:Molecular subtypes of breast cancer are characterized by patterns of gene expression, which can be used to predict response to therapy and overall clinical outcome. The luminal breast cancer subtypes are defined by the expression of ER-alpha (ERa) and a set of ERa-associated genes. The transcription factor activator protein 2C (TFAP2C, AP-2C, AP-2g) transcription factor plays a critical role in regulating cell growth and differentiation during ectodermal development and has been implicated in the regulation of ERa and other luminal-associated genes in breast cancer. While TFAP2C has been established as a prognostic factor in human breast cancer, the role of TFAP2C in development of the luminal epithelial cells in the normal mammary gland and in breast cancer have remained elusive. Herein, we demonstrate a critical role of TFAP2C in maintaining the luminal differentiation phenotype during normal mammary development and in luminal breast carcinoma cell lines. Total RNA from MCF7 cells with and without knockdown of TFAP2c. 3 biological replicates, with 2 technical replicates each, were performed for each sample type.
Project description:Rank signaling regulates mammary gland development and epithelial cell differentiation. Rank receptor is expressed by mammary basal and luminal populations, but, unlike luminal Rank, the contribution of basal Rank signaling to MG homeostasis remains poorly studied. We have combined timely regulated basal specific Rank expression with lineage tracing models and unveiled that basal Rank signaling controls basal cell identity in postnatal mammary glands. Ectopic basal Rank disrupts basal but also luminal cell identity, resulting in aberrant luminal-like differentiation of basal cells and impaired lactogenesis. Mechanistically, overactivation of basal Rank signaling leads to basal cell lineage infidelity, illustrated by the appearance of premalignant lesions composed by a basal-derived hybrid population with alveolar features which ultimately generates basal and luminal breast adenocarcinomas. Proteomic, transcriptomic and chromatin analyses support that the loss of tumor suppressive epigenetic regulators driven by basal Rank contributes to epithelial cell dedifferentiation and tumorigenesis. The basal Rank signature generated associates to poor prognosis particularly in human adenocarcinomas of the luminal subtype stressing the clinical relevance of our findings. Interestingly, our results reinforce the idea that luminal breast tumors might originate from basal cells that have suffered a luminal-like aberrant dedifferentiation triggered by Rank signaling.
Project description:Molecular subtypes of breast cancer are characterized by patterns of gene expression, which can be used to predict response to therapy and overall clinical outcome. The luminal breast cancer subtypes are defined by the expression of ER-alpha (ERa) and a set of ERa-associated genes. The transcription factor activator protein 2C (TFAP2C, AP-2C, AP-2g) transcription factor plays a critical role in regulating cell growth and differentiation during ectodermal development and has been implicated in the regulation of ERa and other luminal-associated genes in breast cancer. While TFAP2C has been established as a prognostic factor in human breast cancer, the role of TFAP2C in development of the luminal epithelial cells in the normal mammary gland and in breast cancer have remained elusive. Herein, we demonstrate a critical role of TFAP2C in maintaining the luminal differentiation phenotype during normal mammary development and in luminal breast carcinoma cell lines.
Project description:Metastasis accounts for almost 90% of breast cancer-related fatalities, making it frequent malignancy and the main reason of tumor mortality globally among women. A key player in breast cancer is the histone demethylase lysine-specific demethylase 1 (LSD1). We used LSD1 knockdown MCF7 and T47D cell exosomes to treat breast cancer cells for greatly increasing the invasion and migration of breast cancer cells for evaluating the impact of LSD1 on breast cancer invasion and migration. miR-1290 expression was downregulated in LSD1 knockdown MCF7 exosomes. Furthermore, miR-1290 could control NAT1 expression by looking through the database of miR-1290 target genes. These data provide fresh insights into the biology of breast cancer therapy by demonstrating how the epigenetic factor LSD1 stimulates the breast cancer cells’ invasion and migration via controlling exosomal miRNA.
Project description:Emerging data indicate that breast epithelial stem cells and progenitors, particularly those in the luminal epithelial cell lineage, are the cells-of-origin of breast carcinomas, and factors that influence breast cancer risk may alter the number and/or properties of these cells. We hypothesize that a subset of p27+ cells represent hormone-responsive progenitors that are quiescent due to the high activity of TGFβ signaling in these cells. The Estrogen-induced mammary tumor model in ACI inbred rats is physiologically relevant rodent model of breast cancer. In the present study we successfully generated Cdkn1b knockout ACI rats and performed comprehensive phenotypic assessment and RNAseq profiling using FACS sorted basal (CD24+CD29high) and luminal (CD24+CD29low) cell populations to characterize Cdkn1b+/+ and Cdkn1b-/- females in prepubertal and adult cohorts. We found that p27KO rats exhibited mammary differentiation phenotype and reduced numbers of mammary epithelial progenitor pool, Interestingly, p27 ablation has the most pronounced effect on luminal progenitor cell gene expression, and milk protein genes and pStat5 were dramatically upregulated, while PR and FoxA1 were greatly downregulated in Cdkn1b-/- luminal cells. Further characterization of mammary glands of prepubertal Cdkn1b knockout rats by fat pad transplantation illustrated p27 deletion in the mammary cancer susceptible ACI rat strain induced mammary epithelial cell differentiation through cell non-autonomous mechanisms.