COUP-TFII regulates tumor growth and metastasis by modulating tumor angiogenesis.
ABSTRACT: Tumor growth depends on nutrients and oxygen supplied by the vasculature through angiogenesis. Here, we show that the chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII), a member of the nuclear receptor family, is a major angiogenesis regulator within the tumor microenvironment. Conditional ablation of COUP-TFII in adults severely compromised neoangiogenesis and suppressed tumor growth in xenograft mouse models. In addition, tumor growth and tumor metastasis were also impaired in a spontaneous mammary-gland tumor model in the absence of COUP-TFII. We showed that COUP-TFII directly regulates the transcription of Angiopoietin-1 in pericytes to enhance neoangiogenesis. Importantly, provision of Angiopoietin-1 partially restores the angiogenic defects exhibited by the COUP-TFII-deficient mice, which supports the notion that COUP-TFII controls Angiopoietin-1/Tie2 signaling to regulate tumor angiogenesis. Because COUP-TFII has little impact on normal adult physiological function, our results raise an interesting possibility that inhibition of COUP-TFII may offer a therapeutic approach for anticancer intervention.
Project description:The significance of angiogenesis in cancer biology and therapy is well established. In this study, we used the prototypical RIP-Tag model of multistage pancreatic islet tumorigenesis to show that the nuclear receptor COUP-TFII is essential to regulate the balance between pro- and anti-angiogenic molecules that influence the angiogenic switch in cancer. Conditional ablation of COUP-TFII in the tumor microenvironment severely compromised neoangiogenesis and lymphangiogenesis during pancreatic tumor progression and metastasis. We found that COUP-TFII plays a cell-autonomous role in endothelial cells to control blood vessel sprouting by regulating cell proliferation and migration. Mechanistic investigations revealed that COUP-TFII suppressed vascular endothelial growth factor (VEGF)/VEGF receptor-2 (VEGFR-2) signaling by transcriptionally repressing the expression of VEGFR-1, thereby curtailing a central angiogenic driver of vascular growth. Taken together, our results implicate COUP-TFII as a critical factor in tumor angiogenesis through regulation of VEGF/VEGFR-2 signaling, suggesting COUP-TFII as a candidate target for antiangiogenic therapy.
Project description:COUP-TFII, a member of the nuclear receptor superfamily plays a critical role in angiogenesis and organogenesis during embryonic development. Our results indicate that COUP-TFII expression is profoundly upregulated in prostate cancer patients and might serves as biomarker for recurrence prediction. Thus we conduct transcriptome comparison of control and COUP-TFII depleted PC3 cells to gain genomic insights on the biological processes that COUP-TFII is involved in prostate cancer cells. Ingenuity Pathway Analysis (IPA) shows that the most prominent altered pathways in the COUP-TFII depleted cells are related to cell growth; cell cycle progression and DNA damage response. Indeed many growth related genes including E2F1, p21, CDC25A, Cyclin A and Cyclin B are changed in COUP-TFII knockdown cells, suggesting that COUP-TFII might be an important regulator for prostate cancer cell growth. Further functional assays from cells and mice genetic studies confirm the hypothesis that COUP-TFII serve as the major regulator to control prostrate cancer growth. Together, results provide insight into the role of COUP-TFII in prostate tumorigenesis. PC3 Cells were transfected with siRNA (Control or COUP-TFII siRNA) duplexes (40 nM) and total RNA was isolated 48 hours later.
Project description:The chicken ovalbumin upstream promoter transcription factors (COUP-TFs), members of the nuclear receptor superfamily, consist of two highly homologous subtypes, COUP-TFI (EAR-3, NR2F1) and COUP-TFII (ARP-1, NR2F2). They are referred to as orphan receptors because the COUP-TF ligands have yet to be identified. Since the discovery of COUP-TFs in 1986, extensive studies have demonstrated their crucial functions in a variety of developmental processes, such as organogenesis, angiogenesis, and metabolic homeostasis. Recently, emerging evidence has highlighted that COUP-TFs, specifically COUP-TFII, play important roles in tumorigenesis. In this review, we will discuss the critical functions of COUP-TFII in the development of the tumor microenvironment, the progression of various cancers, and its underlying mechanisms.
Project description:Chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII; NR2F2) is an orphan nuclear receptor involved in cell-fate specification, organogenesis, angiogenesis, and metabolism. Ablation of COUP-TFII in the mouse uterus causes infertility due to defects in embryo attachment and impaired uterine stromal cell decidualization. Although the function of COUP-TFII in uterine decidualization has been described in mice, its role in the human uterus remains unknown. We observed that, as in mice, COUP-TFII is robustly expressed in the endometrial stroma of healthy women, and its expression is reduced in the ectopic lesions of women with endometriosis. To interrogate the role of COUP-TFII in human endometrial function, we used a small interfering RNA-mediated loss of function approach in primary human endometrial stromal cells. Attenuation of COUP-TFII expression did not completely block decidualization; rather it had a selective effect on gene expression. To better elucidate the role of COUP-TFII in endometrial stroma cell biology, the COUP-TFII transcriptome was defined by pairing microarray comparison with chromatin immunoprecipitation followed by deep sequencing. Gene ontology analysis demonstrates that COUP-TFII regulates a subset of genes in endometrial stroma cell decidualization such as those involved in cell adhesion, angiogenesis, and inflammation. Importantly this analysis shows that COUP-TFII plays a role in controlling the expression of inflammatory cytokines. The determination that COUP-TFII plays a role in inflammation may add insight into the role of COUP-TFII in embryo implantation and in endometrial diseases such as endometriosis.
Project description:The nuclear receptors (NRs) belong to a vast family of evolutionary conserved proteins acting as ligand-activated transcription factors. Functionally, NRs are essential in embryogenesis and organogenesis and in adulthood they are involved in almost every physiological and pathological process. Our knowledge of NRs action has greatly improved in recent years, demonstrating that both their expression and activity are tightly regulated by a network of signaling pathways, miRNA and reciprocal interactions. The Chicken Ovalbumin Upstream Promoter Transcription Factor II (COUP-TFII, NR2F2) is a NR classified as an orphan due to the lack of a known natural ligand. Although its expression peaks during development, and then decreases considerably, in adult tissues, COUP-TFII is an important regulator of differentiation and it is variably implicated in tissues homeostasis. As such, alterations of its expression or its transcriptional activity have been studied and linked to a spectrum of diseases in organs and tissues of different origins. Indeed, an altered COUP-TFII expression and activity may cause infertility, abnormality in the vascular system and metabolic diseases like diabetes. Moreover, COUP-TFII is actively investigated in cancer research but its role in tumor progression is yet to be fully understood. In this review, we summarize the current understanding of COUP-TFII in healthy and pathological conditions, proposing an updated and critical view of the many functions of this NR.
Project description:Reduced COUP-TFII expression contributes to endocrine resistance in breast cancer cells. Endocrine-resistant breast cancer cells have higher NFkappa B (NF?B) activity and target gene expression. The goal of this study was to determine if COUP-TFII modulates NF?B activity. Endocrine-resistant LCC9 cells with low endogenous COUP-TFII displayed ?5-fold higher basal NF?B activity than parental endocrine-sensitive MCF-7 breast cancer cells. Transient transfection of LCC9 cells with COUP-TFII inhibited NF?B activation and reduced NF?B target gene expression. COUP-TFII and NF?B were inversely correlated in breast cancer patient samples. Endogenous COUP-TFII coimmunoprecipitated with NF?B subunits RelB and NF?B1 in MCF-7 cells. COUP-TFII inhibited NF?B-DNA binding in vitro and impaired coactivator induced NF?B transactivation. LCC9 cells were growth-inhibited by an NF?B inhibitor and 4-hydroxytamoxifen compared to MCF-7 cells. Together these data indicate a novel role for COUP-TFII in suppression of NF?B activity and explain, in part, why decreased COUP-TFII expression results in an endocrine-resistant phenotype.
Project description:The chicken ovalbumin upstream promoter-transcription factors (COUP-TFI and II) make up the most conserved subfamily of nuclear receptors that play key roles in angiogenesis, neuronal development, organogenesis, cell fate determination, and metabolic homeostasis. Although the biological functions of COUP-TFs have been studied extensively, little is known of their structural features or aspects of ligand regulation. Here we report the ligand-free 1.48 A crystal structure of the human COUP-TFII ligand-binding domain. The structure reveals an autorepressed conformation of the receptor, where helix alpha10 is bent into the ligand-binding pocket and the activation function-2 helix is folded into the cofactor binding site, thus preventing the recruitment of coactivators. In contrast, in multiple cell lines, COUP-TFII exhibits constitutive transcriptional activity, which can be further potentiated by nuclear receptor coactivators. Mutations designed to disrupt cofactor binding, dimerization, and ligand binding, substantially reduce the COUP-TFII transcriptional activity. Importantly, retinoid acids are able to promote COUP-TFII to recruit coactivators and activate a COUP-TF reporter construct. Although the concentration needed is higher than the physiological levels of retinoic acids, these findings demonstrate that COUP-TFII is a ligand-regulated nuclear receptor, in which ligands activate the receptor by releasing it from the autorepressed conformation.
Project description:Mutations in phosphatase and tensin homologue (PTEN) or genomic alterations in the phosphatidylinositol-3-OH kinase-signalling pathway are the most common genetic alterations reported in human prostate cancer. However, the precise mechanism underlying how indolent tumours with PTEN alterations acquire metastatic potential remains poorly understood. Recent studies suggest that upregulation of transforming growth factor (TGF)-? signalling triggered by PTEN loss will form a growth barrier as a defence mechanism to constrain prostate cancer progression, underscoring that TGF-? signalling might represent a pre-invasive checkpoint to prevent PTEN-mediated prostate tumorigenesis. Here we show that COUP transcription factor II (COUP-TFII, also known as NR2F2), a member of the nuclear receptor superfamily, serves as a key regulator to inhibit SMAD4-dependent transcription, and consequently overrides the TGF-?-dependent checkpoint for PTEN-null indolent tumours. Overexpression of COUP-TFII in the mouse prostate epithelium cooperates with PTEN deletion to augment malignant progression and produce an aggressive metastasis-prone tumour. The functional counteraction between COUP-TFII and SMAD4 is reinforced by genetically engineered mouse models in which conditional loss of SMAD4 diminishes the inhibitory effects elicited by COUP-TFII ablation. The biological significance of COUP-TFII in prostate carcinogenesis is substantiated by patient sample analysis, in which COUP-TFII expression or activity is tightly correlated with tumour recurrence and disease progression, whereas it is inversely associated with TGF-? signalling. These findings reveal that the destruction of the TGF-?-dependent barrier by COUP-TFII is crucial for the progression of PTEN-mutant prostate cancer into a life-threatening disease, and supports COUP-TFII as a potential drug target for the intervention of metastatic human prostate cancer.
Project description:Transcription factor COUP-TFII in rodents is important for migration of cortical interneurons from caudal ganglionic eminence (CGE) to the neocortex. Since in human, unlike in rodents, cortical interneurons have both ganglionic eminence (GE) and dorsal cortical origin, we studied the distribution of COUP-TFII in the human developing neocortex from 9 to 22 gestational weeks. COUP-TFII is expressed at all stages studied in the GE and in various cortical zones, from the proliferative ventricular/subventricular zone (VZ/SVZ) to layer I. Gradients of COUP-TFII expression are present in the GE, with peak expression in the CGE, and in the neocortex, from high expression in the temporal and occipital cortex to moderate in the frontal and dorsal cortex. Double immunofluorescence with ?-aminobutyric acid (GABA), calretinin, or calbindin, established that subpopulations of interneurons express COUP-TFII. A small fraction of COUP-TFII(+) cells are progenitor cells that proliferate in the CGE (3.4 ± 0.3%) and in the cortical VZ/SVZ (1.7 ± 0.1%). In summary, COUP-TFII is expressed in the human fetal forebrain in GABAergic cells, according to its possible role in migration of cortical interneurons. The source of these cells seems to be the CGE and, to a smaller extent, the cortical VZ/SVZ.
Project description:Chicken Ovalbumin Upstream Promoter-Transcription Factor II (COUP-TFII) plays pivotal roles in cell growth, cell differentiation, and cell fate determination. Although genome-wide studies have identified COUP-TFII binding on gene sets mainly involved in neural crest cell (NCC) development and craniofacial morphogenesis, the direct functional connection between COUP-TFII and NCCs in vivo has not been well characterized. In this study, we show that COUP-TFII is expressed in the subpopulation of NCCs and its derivatives, and targeted ablation of COUP-TFII in mouse NCCs results in markedly shortened and bifurcated tympanic rings, which in turn disturb the caudal direction of external acoustic meatus invagination. However, formation of the manubrium of the malleus (MM) in Wnt1-Cre/+;COUP-TFII flox/flox mice is not perturbed, suggesting that the rostral half of the tympanic ring is sufficient to support proper MM development. Interestingly, we found that loss of COUP-TFII up-regulates Sox9 in the tympanic ring primordium and affects the distribution of preosteoblasts before mesenchymal condensation. Together, our results demonstrate that COUP-TFII plays an essential role in regulating the patterning of the NCC-derived tympanic ring.