Project description:Breast cancer (BC) is the most common cancer in women worldwide, and is classified in multiple subtypes, including the so called triple-negative BC (TNBC). This is characterized by lack of estrogen receptor alpha (ERα), progesterone receptor (PR) and epidermal growth factor receptor 2 (HER2/neu), that represent common targets for BC treatment. Their absence limits the number of therapies that may be applied for TNBC treatment, suggesting the need to identify novel therapeutic targets against this disease. Several studies reported that the beta ER subtype (ERβ) is expressed in a sizeable fraction of TNBCs where its presence correlates with improved patient outcome. We evaluated ERβ expression in TNBC tissues by immunohistochemistry using two validated antibodies, demonstrating presence of this protein in 28% of samples. To investigate, in this context, the role of this estrogen receptor in TNBC biology, ERβ-expressing cell lines, representing different TNBC subtypes, were generated. Cellular and functional assays confirmed the antiproliferative activity of ERβ in TNBCs. Interaction proteomics revealed in BC nuclei the presence of several protein complexes associated with this receptor involved in chromatin remodeling, miRNA maturation and mRNA transcription. Transcriptome analyses pointed out tumor subtype-specific signaling pathways deregulation. Interestingly, among these the cholesterol biosynthesis pathway was commonly downregulated in all cell lines tested. Global analyses of ERβ binding to the genome showed its recruitment to regulatory sites of Sterol Regulatory Element-Binding Protein 1 (SREBP1), indicating a direct regulation of this pathway by the receptor. These findings suggest that drugs targeting components of cholesterol biosynthesis pathway may be new potential therapeutic options for TNBC treatment.
Project description:Breast cancer (BC) is the most common cancer in women worldwide, and is classified in multiple subtypes, including the so called triple-negative BC (TNBC). This is characterized by lack of estrogen receptor alpha (ERα), progesterone receptor (PR) and epidermal growth factor receptor 2 (HER2/neu), that represent common targets for BC treatment. Their absence limits the number of therapies that may be applied for TNBC treatment, suggesting the need to identify novel therapeutic targets against this disease. Several studies reported that the beta ER subtype (ERβ) is expressed in a sizeable fraction of TNBCs where its presence correlates with improved patient outcome. We evaluated ERβ expression in TNBC tissues by immunohistochemistry using two validated antibodies, demonstrating presence of this protein in 28% of samples. To investigate, in this context, the role of this estrogen receptor in TNBC biology, ERβ-expressing cell lines, representing different TNBC subtypes, were generated. Cellular and functional assays confirmed the antiproliferative activity of ERβ in TNBCs. Interaction proteomics revealed in BC nuclei the presence of several protein complexes associated with this receptor involved in chromatin remodeling, miRNA maturation and mRNA transcription. Transcriptome analyses pointed out tumor subtype-specific signaling pathways deregulation. Interestingly, among these the cholesterol biosynthesis pathway was commonly downregulated in all cell lines tested. Global analyses of ERβ binding to the genome showed its recruitment to regulatory sites of Sterol Regulatory Element-Binding Protein 1 (SREBP1), indicating a direct regulation of this pathway by the receptor. These findings suggest that drugs targeting components of cholesterol biosynthesis pathway may be new potential therapeutic options for TNBC treatment.
Project description:Breast cancer (BC) is the second most common type of cancer in women and one of the leading causes of cancer-related deaths worldwide. BC classification is based on the detection of three main histological markers: estrogen receptor alpha (ERα), progesterone receptor (PR) and the amplification of epidermal growth factor receptor 2 (HER2/neu). A specific BC subtype, named triple-negative BC (TNBC), lacks the aforementioned markers but a fraction of them express the estrogen receptor beta (ERβ). To investigate the functional role of ERβ in these tumors, interaction proteomics coupled to mass spectrometry (MS) was applied to deeply characterize the nuclear interactors partners in MDA-MD-468 and HCC1806 TNBC cells.
Project description:The goal of this work was to identify all estrogen receptor beta target genes using RNA sequencing in MDA-MB-468 triple negative breast cancer cells engineered with inducible expression of full length estrogen receptor beta.
Project description:The goal of this work was to identify all estrogen receptor beta target genes using RNA sequencing in MDA-MB-468 triple negative breast cancer cells engineered with inducible expression of full length estrogen receptor beta. MDA-MB-468 breast cancer cells with inducible ERb expression (MDA-468-ERb cells) were treated in triplicate with vehicle (control, no ERb) or doxycycline (plus ERb) for 48 hr prior to treatment with 0.1% DMSO vehicle or 10 nM 17b-estradiol for 4 hr.
Project description:Triple Negative Breast Cancer (TNBC) is an aggressive subtype of breast cancer characterized by the absence of estrogen receptor alpha, progesterone receptor, and human epidermal growth factor receptor 2 (HER2). These receptors are well characterized and often serve as targets in breast cancer treatment. As a result, TNBCs are difficult to treat and have a high propensity to metastasize to distant organs. For these reasons, TNBCs are responsible for over 50% of all breast cancer mortalities while only accounting for 15% - 20% of breast cancer cases. However, estrogen receptor beta 1 (ERβ1) has emerged as a potential therapeutic target in the treatment of TNBCs. Using an in vivo xenograft preclinical mouse model with human TNBC, we found that expression of ERβ1 significantly reduced both primary tumor growth and metastasis in the animals. Moreover, TNBCs with elevated levels of ERβ1 showed reduction in epithelial-to-mesenchymal transition (EMT) markers and breast cancer stem cell (BCSC) markers, and increases in the expression of genes associated with inhibition of cancer cell invasiveness and metastasis, suggesting possible mechanisms underlying the antitumor activity of ERβ1. Treatment with ERβ1 agonist ligand often enhanced the suppressive activity of ERβ1, suggesting their potential utility in improving TNBC treatment. The findings enable understanding of the mechanisms by which ERβ impedes TNBC growth, invasiveness and metastasis and consideration of ways by which treatments involving ERβ might improve TNBC patient outcome.
Project description:Targeted therapies for triple-negative breast cancer have increased the number of available treatment options for patients. However, an optimal treatment strategy is still an unmet medical need due to the lack of targetable biomarkers and tumour heterogeneity. Aptamers have high selectivity and specificity towards target proteins. Lower molecular weight, increased stability, less immunogenicity, and rapid tissue uptake make aptamers an attractive alternative to antibodies. Attempts to develop aptamer therapeutics have shown difficulties translating in vitro results to in vivo. Aptamer GreenB1 exhibits selectivity to triple-negative MDA-MB-231 human breast cancer cell line in vitro compared to estrogen, progesterone, and glucocorticoid receptor-expressing MCF-7 human breast cancer cell line. The aptamer is rapidly internalised into cells and trafficked to lysosomes. Here, we identify 1-integrin as the target protein for GreenB1 using proximity labelling and mass spectrometry proteomics. GreenB1 homes preferentially to the tumour in the 4T1 triple-negative breast cancer mice model in vivo.
Project description:Triple negative breast cancer (TNBC) is a highly heterogeneous disease representing the most aggressive breast cancer (BC) subtype. Lack of Estrogen Receptor alpha (ERα), progesterone receptor (PR) and epidermal growth factor receptor 2 (HER2/neu) expression makes TNBC immune to common therapies, significantly limiting the treatment options and suggesting the need to identify novel therapeutic targets. It was previously reported that Estrogen Receptor beta (ERβ) is expressed in a fraction of TNBC patients, where its presence correlates with improved patient outcome. Recently, we demonstrated an oncosuppressive ERβ effect in TNBC cell models expressing exogenous ERβ. On the other hand, it was shown that ERβ is involved in miRNA-mediated gene regulation in hormone-responsive BC cells, suggesting similar effect also in TNBC. To verify this hypothesis, we performed small non-coding RNA (sncRNA) sequencing on three engineered cell lines belonging to different TNBC molecular subtypes. ERβ-specific changes of sncRNA profile revealed that the major part of deregulated molecules are subtype specific, with only few commonly regulated ones. In order to validate the obtained results, we performed sncRNA profiling of 12 ERβ positive and 32 ERβ negative TNBC tissues, whose receptor status was assessed by immunohistochemistry in our previous research. Also here, ERβ-specific group of deregulated sncRNAs was identified. Interestingly, comparison of obtained in vitro and in vivo results revealed 2 differentially expressed miRNAs, displaying the same behavior in all three analyzed cell lines and tissues. In concordance with our previous results, IPA signaling pathway analysis performed on genes targeted by deregulated miRNAs highlighted downregulation of cholesterol biosynthesis pathway and upregulation of several signaling processes. Taken together, these findings suggest that ERβ is able to exert its oncosuppressive role in TNBC through miRNA-mediated regulation of gene expression.
Project description:This study aimed to investigate whether the BET inhibitor JQ1 could alter the hypoxia-induced upregulation of gene expression and have an anti-tumour effect associated with this mechanism. We showed JQ1 downregulates 44% of hypoxia upregulated genes, including CA9 and VEGF-A. We demonstrated that JQ1 reduces triple receptor negative breast cancer (TNBC) tumour growth in monolayer and spheroid (3D) cell culture.