Project description:ABSTRACT: Obesity is responsible for decreased overall survival for breast cancer patients. Here, we describe the generation, characterization and application of a novel murine mammary tumor initiating cell model (M-Wnt) that recapitulates the claudin-low subtype of human breast cancer and permits the study of TIC’s in wild-type, immunocompetent mice. M-Wnt cells readily form mammospheres in suspension culture, express markers consistent with epithelial-to-mesenchymal transition (EMT), and generate claudin-low mammary tumors when as few as 50 cells are orthotopically injected. Using the M-Wnt cell lines in tandem with a more basal-like epithelial breast cancer cell line, E-Wnt, we found that diet induced obesity significantly downregulates epithelial markers, such as E-cadherin, and upregulates mesenchymal markers including fibronectin, N-cadherin, SNAIL, Oct-4, and TGF-b. This reveals a previously unidentified link between energy balance and EMT. The ability of calorie restriction (CR) to reverse EMT, upregulate epithelial markers and downregulate mesenchymal markers indicates the plasticity of the TICs, as well as the potential importance of lifestyle modifications as cancer prevention strategies. 28 array samples
Project description:ABSTRACT: Obesity is responsible for decreased overall survival for breast cancer patients. Here, we describe the generation, characterization and application of a novel murine mammary tumor initiating cell model (M-Wnt) that recapitulates the claudin-low subtype of human breast cancer and permits the study of TIC’s in wild-type, immunocompetent mice. M-Wnt cells readily form mammospheres in suspension culture, express markers consistent with epithelial-to-mesenchymal transition (EMT), and generate claudin-low mammary tumors when as few as 50 cells are orthotopically injected. Using the M-Wnt cell lines in tandem with a more basal-like epithelial breast cancer cell line, E-Wnt, we found that diet induced obesity significantly downregulates epithelial markers, such as E-cadherin, and upregulates mesenchymal markers including fibronectin, N-cadherin, SNAIL, Oct-4, and TGF-b. This reveals a previously unidentified link between energy balance and EMT. The ability of calorie restriction (CR) to reverse EMT, upregulate epithelial markers and downregulate mesenchymal markers indicates the plasticity of the TICs, as well as the potential importance of lifestyle modifications as cancer prevention strategies.
Project description:Epithelial-mesenchymal transition (EMT) is a diverse and dynamic biological process which is involved in cancer progression. It is important for carcinoma cells during invasion and metastasis. EMT has been in the spotlight for cancer cells to disseminate to distant organs by gaining partial EMT phenotype. Cancer cells with partial EMT are believed to be more cancerogenic/invasive than cells that have undergone complete EMT. The proteomic changes that occur following EMT in breast epithelial cells and how these relate to changes in cellular metabolism are incompletely understood. To study metabolic reprogramming in different mesenchymal states, we analyzed proteomic changes following EMT in the breast epithelial cell model D492, with single-shot LFQ supported by SILAC proteomic approach. The D492 EMT cell model contains three isogenic cell lines: epithelial D492 cells, mesenchymal D492M cells, and partial mesenchymal, HER2 overexpressing, tumorigenic D492HER2 cells. Proteomic analysis positioned the D492 and D492M cells as basal-like while D492HER2 as claudin-low. Further comparison of the non-tumorigenic D492 and D492M cells to tumorigenic D492HER2 differentiated the metabolic EMT markers of migration from those of invasion. Among these were markers of glycan metabolism. We identified glutamine-fructose-6-phosphate transaminase [isomerizing] 2 (GFPT2) as the top dysregulated enzyme in glycan metabolism and found increased GFPT2 expression was a characteristic of claudin-low breast cancer. siRNA knockdown of GFPT2 influenced both cell growth and invasion in vitro and was accompanied by lowered flux through the hexosamine biosynthesis pathway (HBP). Knockdown of GFPT2 decreased cystathionine and sulfide:quinone oxidoreductase (SQOR) in the transsulfuration pathway which regulates H2S production and mitochondrial homeostasis. Moreover, GFPT2 expression was regulated by the level of reduced glutathione (GSH) and suppressed by the oxidative stress regulator, GSK3-β. Our results demonstrate that GFPT2 is a marker for oxidative stress. It is upregulated and controls growth and invasion in the D492 EMT model and is associated with claudin-low and poor prognosis in breast cancer.
Project description:Epithelial-mesenchymal transition (EMT) is a diverse and dynamic biological process which is involved in cancer progression. It is important for carcinoma cells during invasion and metastasis. EMT has been in the spotlight for cancer cells to disseminate to distant organs by gaining partial EMT phenotype. Cancer cells with partial EMT are believed to be more cancerogenic/invasive than cells that have undergone complete EMT. The proteomic changes that occur following EMT in breast epithelial cells and how these relate to changes in cellular metabolism are incompletely understood. To study metabolic reprogramming in different mesenchymal states, we analyzed proteomic changes following EMT in the breast epithelial cell model D492, with single-shot LFQ supported by SILAC proteomic approach. The D492 EMT cell model contains three isogenic cell lines: epithelial D492 cells, mesenchymal D492M cells, and partial mesenchymal, HER2 overexpressing, tumorigenic D492HER2 cells. Proteomic analysis positioned the D492 and D492M cells as basal-like while D492HER2 as claudin-low. Further comparison of the non-tumorigenic D492 and D492M cells to tumorigenic D492HER2 differentiated the metabolic EMT markers of migration from those of invasion. Among these were markers of glycan metabolism. We identified glutamine-fructose-6-phosphate transaminase [isomerizing] 2 (GFPT2) as the top dysregulated enzyme in glycan metabolism and found increased GFPT2 expression was a characteristic of claudin-low breast cancer. siRNA knockdown of GFPT2 influenced both cell growth and invasion in vitro and was accompanied by lowered flux through the hexosamine biosynthesis pathway (HBP). Knockdown of GFPT2 decreased cystathionine and sulfide:quinone oxidoreductase (SQOR) in the transsulfuration pathway which regulates H2S production and mitochondrial homeostasis. Moreover, GFPT2 expression was regulated by the level of reduced glutathione (GSH) and suppressed by the oxidative stress regulator, GSK3-β. Our results demonstrate that GFPT2 is a marker for oxidative stress. It is upregulated and controls growth and invasion in the D492 EMT model and is associated with claudin-low and poor prognosis in breast cancer.
Project description:Claudin-low tumors are a highly aggressive breast cancer subtype with no targeted treatments and a clinically documented resistance to chemotherapy. They are significantly enriched in cancer stem cells (CSCs), which makes claudin-low tumor models particularly attractive for studying CSC behavior and developing novel approaches to minimize CSC therapy resistance. One proposed mechanism by which CSCs arise is via an epithelial-mesenchymal transition (EMT), and reversal of this process may provide a potential therapeutic approach for increasing tumor chemosensitivity. Therefore, we investigated the role of the miR-200 family of microRNAs in regulating the epithelial state, stem-like properties, and therapeutic response in an in vivo primary, syngeneic p53null claudin-low tumor model that is normally deficient in miR-200 expression. Using an inducible lentiviral approach, we expressed the miR-200c cluster in this claudin-low model and found that it changed the epithelial state, and consequently, impeded CSC behavior in these mesenchymal tumors. Moreover, these state changes were accompanied by a decrease in proliferation and an increase in the differentiation status. MiR-200c expression also forced a significant reorganization of tumor architecture, affecting important cellular processes involved in cell-cell contact, cell adhesion, and motility. Accordingly, induced miR200c expression also significantly enhanced the chemosensitivity and decreased the metastatic potential of this p53null claudin-low tumor model. Collectively, our data suggest that miR-200c expression in claudin-low tumors offers a potential therapeutic application to disrupt the EMT program on multiple fronts in this mesenchymal tumor subtype, by altering tumor growth, chemosensitivity, and metastatic potential in vivo. reference x sample
Project description:The newly identified claudin-low subtype of cancer is believed to represent the most primitive breast malignancies, having arisen from transformation of an early epithelial precursor with inherent stemness properties and metaplastic features. Challenging this hypothesis, we show both in vitro and in vivo that transcription factors inducing epithelial-mesenchymal transition can drive the development of claudin-low tumors from differentiated mammary epithelial cells, by playing a dual role in cell transformation and dedifferentiation. Gene expression profiles of three independent Twist1 + Ras- transgenic mouse-derived metaplastic breast tumors (Breast Tumor A, B and C) and of two luminal MMTV-ERBB2/Neu-breast tumor-derived cell lines (1 and 2) were determined.
Project description:The Epithelial–Mesenchymal Transition (EMT) and primary ciliogenesis induce stem cell properties in basal Mammary Stem Cells (MaSCs) to promote mammogenesis, but the underlying mechanisms remain incompletely understood. Here, we show that EMT transcription factors promote ciliogenesis upon intermediate EMT transition states by activating ciliogenesis inducers, including FGFR1. The resulting primary cilia promote BBS11-dependent ubiquitination and inactivation of a central signaling node, GLIS2. We show that GLIS2 inactivation promotes MaSC stemness, and GLIS2 is required for normal mammary gland development. Moreover, GLIS2 inactivation is required to induce the proliferative and tumorigenic capacities of the Mammary-Tumor-initiating cells (MaTICs) of claudin-low breast cancers. Claudin-low breast tumors can be segregated from other breast tumor subtypes based on a GLIS2-dependent gene expression signature. Collectively, our findings establish molecular mechanisms by which EMT programs induce ciliogenesis to control MaSC and MaTIC biology, mammary gland development, and claudin-low breast cancer formation.
Project description:The newly identified claudin-low subtype of cancer is believed to represent the most primitive breast malignancies, having arisen from transformation of an early epithelial precursor with inherent stemness properties and metaplastic features. Challenging this hypothesis, we show both in vitro and in vivo that transcription factors inducing epithelial-mesenchymal transition can drive the development of claudin-low tumors from differentiated mammary epithelial cells, by playing a dual role in cell transformation and dedifferentiation.
Project description:The newly identified claudin-low subtype of cancer is believed to represent the most primitive breast malignancies, having arisen from transformation of an early epithelial precursor with inherent stemness properties and metaplastic features. Challenging this hypothesis, we show both in vitro and in vivo that transcription factors inducing epithelial-mesenchymal transition can drive the development of claudin-low tumors from differentiated mammary epithelial cells, by playing a dual role in cell transformation and dedifferentiation.
Project description:The miR-200 family of microRNAs consisting of miR-141, miR-200a, miR-200b, miR-200c and miR-429 are key regulators of breast cancer progression. The miR200 family maintains mammary epithelial identity and downregulation of miR-200 expression drives the epithelial-to-mesenchymal transition. Re-expression of one or more miR-200 family members in tumor cells with mesenchymal characteristics may restore the epithelial phenotype and alter growth and metastatic potential. To test this, the miR-200b/200a/429 cluster was re-expressed in a murine claudin-low mammary tumor cell line, RJ423