The RIP140 gene is a transcriptional target of E2F1

E2F transcription factor 5, a new regulator in adipogenesis to mediate the role of Krüppel-like factor 7 in chicken preadipocyte differentiation and proliferation

E2F transcription factor 5 (E2F5) gene is a transcription factor, plays an important role in the development of a variety of cells. E2F5 is expressed in human and mouse adipocytes, but its specific function in adipogenesis is unclear. Krüppel-like factor 7 (KLF7) facilitates proliferation and inhibits differentiation in chicken preadipocytes. Our previous KLF7 chromatin immunoprecipitation-sequencing analysis revealed a KLF7-binding peak in the 3' flanking region of the E2F5, indicating a regulatory role of KLF7 in this region. In the present study, we investigated E2F5 potential role, the overexpression and knockdown analyses revealed that E2F5 inhibited the differentiation and promoted the proliferation of chicken preadipocytes. Moreover, we identified enhancer activity in the 3' flanking region (nucleotides +22661/+22900) of E2F5 and found that KLF7 overexpression increased E2F5 expression and luciferase activity in this region. Deleting the putative KLF7-binding site eliminated the promoting effect of KLF7 overexpression on E2F5 expression. Further, E2F5 reversed the KLF7-induced decrease in preadipocyte differentiation and increase in preadipocyte proliferation. Taken together, our findings demonstrate that KLF7 inhibits differentiation and promotes proliferation in preadipocytes by enhancing E2F5 transcription.

RIP140 regulates transcription factor HES1 oscillatory expression and mitogenic activity in colon cancer cells

The transcription factor receptor-interacting protein 140 (RIP140) regulates intestinal homeostasis and tumorigenesis through Wnt signaling. In this study, we investigated its effect on the Notch/HES1 signaling pathway. In colorectal cancer (CRC) cell lines, RIP140 positively regulated HES1 gene expression at the transcriptional level via a recombining binding protein suppressor of hairless (RBPJ)/neurogenic locus notch homolog protein 1 (NICD)-mediated mechanism. In support of these in vitro data, RIP140 and HES1 expression significantly correlated in mouse intestine and in a cohort of CRC samples, thus supporting the positive regulation of HES1 gene expression by RIP140. Interestingly, when the Notch pathway is fully activated, RIP140 exerted a strong inhibition of HES1 gene transcription controlled by the level of HES1 itself. Moreover, RIP140 directly interacts with HES1 and reversed its mitogenic activity in human CRC cells. In line with this observation, HES1 levels were associated with a better patient survival only when tumors expressed high levels of RIP140. Our data identify RIP140 as a key regulator of the Notch/HES1 signaling pathway, with a dual effect on HES1 gene expression at the transcriptional level and a strong impact on colon cancer cell proliferation.

NRIP1 regulates cell proliferation in lung adenocarcinoma cells

Nuclear receptor interacting protein 1 (NRIP1) is a transcription cofactor that regulates the activity of nuclear receptors and transcription factors. Functional expression of NRIP1 has been identified in multiple cancers. However, the expression and function of NRIP1 in lung adenocarcinoma have remained unclear. Thus, we aimed to clarify the NRIP1 expression and its functions in lung adenocarcinoma cells. NRIP1 and Ki-67 were immunostained in the tissue microarray section consisting of 64 lung adenocarcinoma cases, and the association of NRIP1 immunoreactivity with clinical phenotypes was examined. Survival analysis was performed in lung adenocarcinoma data from The Cancer Genome Atlas (TCGA). Human A549 lung adenocarcinoma cell line with an NRIP1-silencing technique was used in vitro study. Forty-three of 64 cases were immunostained with NRIP1. Ki-67-positive cases were more frequent in NRIP1-positive cases as opposed to NRIP1-negative cases. Higher NRIP1 mRNA expression was associated with poor prognosis in the TCGA lung adenocarcinoma data. NRIP1 was mainly located in the nucleus of A549 cells. NRIP1 silencing significantly reduced the number of living cells, suppressed cell proliferation, and induced apoptosis. These results suggest that NRIP1 participates in the progression and development of lung adenocarcinoma. Targeting NRIP1 may be a possible therapeutic strategy against lung adenocarcinoma.

Receptor-Interacting Protein 140 Enhanced Temozolomide-Induced Cellular Apoptosis Through Regulation of E2F1 in Human Glioma Cell Lines

Glioblastoma (GBM), a grade IV glioma, is responsible for the highest years of potential life lost among cancers. The poor prognosis is attributable to its high recurrence rate, caused in part by the development of resistance to chemotherapy. Receptor-interacting protein 140 (RIP140) is a very versatile coregulator of nuclear receptors and transcription factors. Although many of the pathways regulated by RIP140 contribute significantly to cancer progression, the function of RIP140 in GBM remains to be determined. In this study, we found that higher RIP140 expression was associated with prolonged survival in patients with newly diagnosed GBM. Intracellular RIP140 levels were increased after E2F1 activation following temozolomide (TMZ) treatment, which in turn modulated the expression of E2F1-targeted apoptosis-related genes. Overexpression of RIP140 reduced glioma cell proliferation and migration, induced cellular apoptosis, and sensitized GBM cells to TMZ. Conversely, knockdown of RIP140 increased TMZ resistance. Taken together, our results suggest that RIP140 prolongs the survival of patients with GBM both by inhibiting tumor cell proliferation and migration and by increasing cellular sensitivity to chemotherapy. This study helps improve our understanding of glioma recurrence and may facilitate the development of more effective treatments.

Prospective study of a diabetes risk reduction diet and the risk of breast cancer

BACKGROUND

Hyperinsulinemia and higher insulin-like growth factors may increase breast cancer risk. We evaluated a diabetes risk reduction diet (DRRD) and breast cancer risk.

OBJECTIVES

We prospectively evaluated the association between adherence to a DRRD and the incidence of breast cancer.

METHODS

We followed 88,739 women from the Nurses' Health Study (NHS; 1980-2016) and 93,915 women from the NHSII (1991-2017). Incident breast cancer cases (n = 11,943) were confirmed with medical records, and subtypes were determined by tissue microarray data and pathology reports. Information on diet and breast cancer risk factors was repeatedly ascertained in follow-up questionnaires. A DRRD score was derived with 9 factors: lower glycemic index of diet; lower intakes of trans fat, sugar-sweetened beverages/fruit juices, and red/processed meat; higher intakes of cereal fiber, coffee, nuts, and whole fruits; and a higher ratio of polyunsaturated to saturated fat (score range: 9-45). Multivariable-adjusted hazard ratios (MVHRs) and 95% CIs were calculated with Cox proportional hazards models.

RESULTS

Being in the highest compared with the lowest DRRD adherence quintile was associated with a modestly lower breast cancer risk (MVHRQ5vsQ1: 0.89; 95% CI: 0.84, 0.95; P-trend = 0.0002); this was attenuated after adjusting for weight change since age 18 y (MVHRQ5vsQ1: 0.92; 95% CI: 0.87, 0.98; P-trend = 0.01). The inverse association was strongest among women with current BMI < 25 kg/m2 (MVHRQ5vsQ1: 0.89; 95% CI: 0.81, 0.98; P-trend = 0.004; P-interaction = 0.04). Among tumor molecular subtypes, the strongest inverse association was observed with basal-type tumors (MVHRQ5vsQ1: 0.67; 95% CI: 0.45, 1.01; P-trend = 0.04).

CONCLUSIONS

Greater DRRD-adherence was associated with lower breast cancer risk, likely mediated by less weight gain with a DRRD; however, independently of weight change, DRRD-adherence was modestly associated with lower breast cancer risk, particularly among lean women.

Deletion of Nrip1 Extends Female Mice Longevity, Increases Autophagy, and Delays Cell Senescence

Using age of female sexual maturation as a biomarker, we previously identified nuclear receptor interacting protein 1 (Nrip1) as a candidate gene that may regulate aging and longevity. In the current report, we found that the deletion of Nrip1 can significantly extend longevity of female mice (log-rank test, p = .0004). We also found that Nrip1 expression is altered differently in various tissues during aging and under diet restriction. Remarkably, Nrip1 expression is elevated with aging in visceral white adipose tissue (WAT), but significantly reduced after 4 months of diet restriction. However, in gastrocnemius muscle, Nrip1 expression is significantly upregulated after the diet restriction. In mouse embryonic fibroblasts, we found that the deletion of Nrip1 can suppress fibroblast proliferation, enhance autophagy under normal culture or amino acid starvation conditions, as well as delay oxidative and replicative senescence. Importantly, in WAT of old animals, the deletion of the Nrip could significantly upregulate autophagy and reduce the number of senescent cells. These results suggest that deleting Nrip1 can extend female longevity, but tissue-specific deletion may have varying effects on health span. The deletion of Nrip1 in WAT may delay senescence in WAT and extend health span.

Investigation of RIP140 and LCoR as independent markers for poor prognosis in cervical cancer

Introduction

RIP140 (Receptor Interacting Protein) is involved in the regulation of oncogenic signaling pathways and in the development of breast and colon cancers. The aim of the study was to analyze the expression of RIP140 and its partner LCoR in cervical cancers, to decipher their relationship with histone protein modifications and to identify a potential link with patient survival.

Methods

Immunohistochemical analyses were carried out to quantify RIP140 and LCoR expression in formalin-fixed paraffin-embedded tissue sections cervical cancer samples. Correlations of RIP140 and LCoR expression with histopathological variables were determined by correlation analyses. Survival rates of patients expressing low or high levels of RIP140 and LCoR were compared by Kaplan-Meier curves.

Results

RIP140 overexpression was associated with a significantly shorter overall survival of cervical cancer patients. This effect was significant in the squamous cell carcinoma subtype but not in adenocarcinomas. RIP140 is no longer a significant negative prognosticator for cervical cancer when LCoR expression is low.

Discussion

RIP140 is an independent predictor of poor survival of patients with cervical cancer. Patients with tumors expressing low levels of both RIP140 and LCoR showed a better survival compared to patients expressing high levels of RIP140. Modulation of RIP140 and LCoR may represent a novel targeting strategy for cervical cancer prevention and therapy.

Transcriptional coregulator RIP140: an essential regulator of physiology

Transcriptional coregulators drive gene regulatory decisions in the transcriptional space. Although transcription factors including all nuclear receptors provide a docking platform for coregulators to bind, these proteins bring enzymatic capabilities to the gene regulatory sites. RIP140 is a transcriptional coregulator essential for several physiological processes, and aberrations in its function may lead to diseased states. Unlike several other coregulators that are known either for their coactivating or corepressing roles, in gene regulation, RIP140 is capable of acting both as a coactivator and a corepressor. The role of RIP140 in female reproductive axis and recent findings of its role in carcinogenesis and adipose biology have been summarised.

E2F1, a Novel Regulator of Metabolism

In the past years, several lines of evidence have shown that cell cycle regulatory proteins also can modulate metabolic processes. The transcription factor E2F1 is a central player involved in cell cycle progression, DNA-damage response, and apoptosis. Its crucial role in the control of cell fate has been extensively studied and reviewed before; however, here, we focus on the participation of E2F1 in the regulation of metabolism. We summarize recent findings about the cell cycle-independent roles of E2F1 in various tissues that contribute to global metabolic homeostasis and highlight that E2F1 activity is increased during obesity. Finally, coming back to the pivotal role of E2F1 in cancer development, we discuss how E2F1 links cell cycle progression with different metabolic adaptations required for cell growth and survival.

Periodic expression of Kv10.1 driven by pRb/E2F1 contributes to G2/M progression of cancer and non-transformed cells

Progression of cell cycle is associated with changes in K⁺ channel expression and activity. In this study, we report that Kv10.1, a K⁺ channel that increases cell proliferation and tumor growth, is regulated at the transcriptional level by the pRb/E2F1 pathway. De-repression of E2F1 by HPV-E7 oncoprotein leads to increased expression of Kv10.1. In proliferating cells, E2F1 transcription factor binds directly to the Kv10.1 promoter during (or close to) G2/M, resulting in transient expression of the channel. Importantly, this happens not only in cancer cells but also in non-transformed cells. Lack of Kv10.1 in both cancer and non-transformed cells resulted in prolonged G2/M phase, as indicated by phosphorylation of Cdk1 (Y15) and sustained pRb hyperphosphorylation. Our results strongly suggest that Kv10.1 expression is coupled to cell cycle progression and facilitates G2/M progression in both healthy and tumor cells.

Most of the tight positional conservation of transcription factor binding sites near the transcription start site reflects their co-localization within regulatory modules

Background

Transcription factors (TFs) form complexes that bind regulatory modules (RMs) within DNA, to control specific sets of genes. Some transcription factor binding sites (TFBSs) near the transcription start site (TSS) display tight positional preferences relative to the TSS. Furthermore, near the TSS, RMs can co-localize TFBSs with each other and the TSS. The proportion of TFBS positional preferences due to TFBS co-localization within RMs is unknown, however. ChIP experiments confirm co-localization of some TFBSs genome-wide, including near the TSS, but they typically examine only a few TFs at a time, using non-physiological conditions that can vary from lab to lab. In contrast, sequence analysis can examine many TFs uniformly and methodically, broadly surveying the co-localization of TFBSs with tight positional preferences relative to the TSS.

Results

Our statistics found 43 significant sets of human motifs in the JASPAR TF Database with positional preferences relative to the TSS, with 38 preferences tight (±5 bp). Each set of motifs corresponded to a gene group of 135 to 3304 genes, with 42/43 (98%) gene groups independently validated by DAVID, a gene ontology database, with FDR < 0.05. Motifs corresponding to two TFBSs in a RM should co-occur more than by chance alone, enriching the intersection of the gene groups corresponding to the two TFs. Thus, a gene-group intersection systematically enriched beyond chance alone provides evidence that the two TFs participate in an RM. Of the 903 = 43*42/2 intersections of the 43 significant gene groups, we found 768/903 (85%) pairs of gene groups with significantly enriched intersections, with 564/768 (73%) intersections independently validated by DAVID with FDR < 0.05. A user-friendly web site at http://go.usa.gov/3kjsH permits biologists to explore the interaction network of our TFBSs to identify candidate subunit RMs.

Conclusions

Gene duplication and convergent evolution within a genome provide obvious biological mechanisms for replicating an RM near the TSS that binds a particular TF subunit. Of all intersections of our 43 significant gene groups, 85% were significantly enriched, with 73% of the significant enrichments independently validated by gene ontology. The co-localization of TFBSs within RMs therefore likely explains much of the tight TFBS positional preferences near the TSS.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-016-1354-5) contains supplementary material, which is available to authorized users.

Suppressing NRIP1 inhibits growth of breast cancer cells in vitro and in vivo

Earlier age at menarche is a major risk factor for breast cancer. Our previous study identified Nrip1 (also known as Rip140) as a candidate gene for delaying female sexual maturation (FSM) and found that knocking out Nrip1 could significantly delay FSM in mice. To investigate the effects of NRIP1 in breast cancer we used human cell lines and tissue arrays along with an in vivo study of DMBA-induced carcinogenesis in Nrip1 knockout mice. Analysis of tissue arrays found that NRIP1 is elevated in tumors compared to cancer adjacent normal tissue. Interestingly, in benign tumors NRIP1 levels are higher in the cytosol of stromal cells, but NRIP1 levels are higher in the nuclei of epithelial cells in malignancies. We also found overexpression of NRIP1 in breast cancer cell lines, and that suppression of NRIP1 by siRNA in these cells significantly induced apoptosis and inhibited cell growth. Furthermore, in vivo data suggests that NRIP1 is upregulated in DMBA-induced breast cancer. Importantly, we found that DMBA-induced carcinogenesis is suppressed in Nrip1 knockdown mice. These findings suggest that NRIP1 plays a critical role in promoting the progression and development of breast cancer and that it may be a potential therapeutic target for the new breast cancer treatments.

The emerging role of the transcriptional coregulator RIP140 in solid tumors

RIP140 is a transcriptional coregulator (also known as NRIP1) which plays very important physiological roles by finely tuning the activity of a large number of transcription factors. Noticeably, the RIP140 gene has been shown to be involved in the regulation of energy expenditure, in mammary gland development and intestinal homeostasis as well as in behavior and cognition. RIP140 is also involved in the regulation of various oncogenic signaling pathways and participates in the development and progression of solid tumors. This short review aims to summarize the role of this transcription factor on nuclear estrogen receptors, E2F and Wnt signaling pathways based on recent observations focusing on breast, ovary, liver and colon tumors.

Regulation of Hepatic Cholesteryl Ester Transfer Protein Expression and Reverse Cholesterol Transport by Inhibition of DNA Topoisomerase II

Cholesteryl ester transfer protein (CETP) transfers cholesteryl esters from high density lipoprotein to triglyceride-rich lipoproteins. CETP expression can be transcriptionally activated by liver X receptor (LXR). Etoposide and teniposide are DNA topoisomerase II (Topo II) inhibitors. Etoposide has been reported to inhibit atherosclerosis in rabbits with un-fully elucidated mechanisms. In this study we determined if Topo II activity can influence cholesterol metabolism by regulating hepatic CETP expression. Inhibition of Topo II by etoposide, teniposide, or Topo II siRNA increased CETP expression in human hepatic cell line, HepG2 cells, which was associated with increased CETP secretion and mRNA expression. Meanwhile, inhibition of LXR expression by LXR siRNA attenuated induction of CETP expression by etoposide and teniposide. Etoposide and teniposide induced LXRα expression and LXRα/β nuclear translocation while inhibiting expression of receptor interacting protein 140 (RIP140), an LXR co-repressor. In vivo, administration of teniposide moderately reduced serum lipid profiles, induced CETP expression in the liver, and activated reverse cholesterol transport in CETP transgenic mice. Our study demonstrates a novel function of Topo II inhibitors in cholesterol metabolism by activating hepatic CETP expression and reverse cholesterol transport.

Expression and role of RIP140/NRIP1 in chronic lymphocytic leukemia

RIP140 is a transcriptional coregulator, (also known as NRIP1), which finely tunes the activity of various transcription factors and plays very important physiological roles. Noticeably, the RIP140 gene has been implicated in the control of energy expenditure, behavior, cognition, mammary gland development and intestinal homeostasis. RIP140 is also involved in the regulation of various oncogenic signaling pathways and participates in the development and progression of solid tumors. During the past years, several papers have reported evidences linking RIP140 to hematologic malignancies. Among them, two recent studies with correlative data suggested that gene expression signatures including RIP140 can predict survival in chronic lymphocytic leukemia (CLL). This review aims to summarize the literature dealing with the expression of RIP140 in CLL and to explore the potential impact of this factor on transcription pathways which play key roles in this pathology.

Downregulation of RIP140 in hepatocellular carcinoma promoted the growth and migration of the cancer cells

Hepatocellular carcinoma (HCC) is one of the most common malignancies with a poor response to chemotherapy. It is very important to identify novel diagnosis biomarkers and therapeutic targets. RIP140, a regulator of estrogen receptor, recently has been found to be involved in the tumorigenesis. However, its function in the progression of HCC remains poorly understood. Here, we found that the expression of RIP140 was downregulated in the HCC tissues. Moreover, overexpression of RIP140 in HCC cells inhibited cell proliferation and migration, while downregulation of RIP140 promoted the tumorigenicity of HCC cells in vitro and in vivo. Mechanistically, RIP140 interacted with beta-catenin and negatively regulated beta-catenin/TCF signaling. Taken together, our study suggests the suppressive roles of RIP140 in the pathogenesis of HCC.

Identification of a 20-gene expression-based risk score as a predictor of clinical outcome in chronic lymphocytic leukemia patients

Despite the improvement in treatment options, chronic lymphocytic leukemia (CLL) remains an incurable disease and patients show a heterogeneous clinical course requiring therapy for many of them. In the current work, we have built a 20-gene expression (GE)-based risk score predictive for patients overall survival and improving risk classification using microarray gene expression data. GE-based risk score allowed identifying a high-risk group associated with a significant shorter overall survival (OS) and time to treatment (TTT) (P ≤ .01), comprising 19.6% and 13.6% of the patients in two independent cohorts. GE-based risk score, and NRIP1 and TCF7 gene expression remained independent prognostic factors using multivariate Cox analyses and combination of GE-based risk score together with NRIP1 and TCF7 gene expression enabled the identification of three clinically distinct groups of CLL patients. Therefore, this GE-based risk score represents a powerful tool for risk stratification and outcome prediction of CLL patients and could thus be used to guide clinical and therapeutic decisions prospectively.

RIP140 increases APC expression and controls intestinal homeostasis and tumorigenesis

Deregulation of the Wnt/APC/β-catenin signaling pathway is an important consequence of tumor suppressor APC dysfunction. Genetic and molecular data have established that disruption of this pathway contributes to the development of colorectal cancer. Here, we demonstrate that the transcriptional coregulator RIP140 regulates intestinal homeostasis and tumorigenesis. Using Rip140-null mice and mice overexpressing human RIP140, we found that RIP140 inhibited intestinal epithelial cell proliferation and apoptosis. Interestingly, following whole-body irradiation, mice lacking RIP140 exhibited improved regenerative capacity in the intestine, while mice overexpressing RIP140 displayed reduced recovery. Enhanced RIP140 expression strongly repressed human colon cancer cell proliferation in vitro and after grafting onto nude mice. Moreover, in murine tissues and human cancer cells, RIP140 stimulated APC transcription and inhibited β-catenin activation and target gene expression. Finally, RIP140 mRNA and RIP140 protein levels were decreased in human colon cancers compared with those in normal mucosal tissue, and low levels of RIP140 expression in adenocarcinomas from patients correlated with poor prognosis. Together, these results support a tumor suppressor role for RIP140 in colon cancer.

Coordinated repressive chromatin-remodeling of Oct4 and Nanog genes in RA-induced differentiation of embryonic stem cells involves RIP140

Maintaining pluripotency and indefinite self-renewal of embryonic stem cells requires a tight control of the expression of several key stemness factors, particularly Nanog and Oct4 transcription factors. The mammalian SWItch/Sucrose NonFermentable (SWI/SNF) complex contains Brg1 or Brm as its core subunit, along with Brg1-associated factors. Our previous studies have addressed chromatin-remodeling of the Oct4 gene locus in retinoic acid (RA)-treated embryonal carcinoma cell line P19, which involves receptor-interacting protein 140 (RIP140) for heterochromatinization on the proximal promoter region of this gene locus. However, the mechanism of RIP140 action in RA-triggered repressive chromatin-remodeling is unclear. The current study examines RA repression of the Nanog gene and compares the results with RA repression of the Oct4 gene on the chromatin level. The results show a loose nucleosome array on the Nanog gene promoter in undifferentiated embryonic stem cells. On RA treatment, the Nanog gene locus remodels specifically in the CR1 region of its proximal promoter, with the insertion of a nucleosome and compaction of this region. Further, RA induces coordinated chromatin-remodeling of both Nanog and Oct4 gene loci, which requires RA receptor-α, RIP140 and Brm. Finally, in these RA-triggered repressive chromatin-remodeling processes, lysine acetylation of RIP140 is critical for its recruiting Brm.

Distinct functions for RIP140 in development, inflammation, and metabolism

Nuclear receptors (NRs) regulate tissue development and function by controlling transcription from distinct sets of genes in response to fluctuating levels of hormones or cues that modulate receptor activity. Such target gene activation or repression depends on the recruitment of coactivators or corepressors that lead to chromatin remodelling in the vicinity of target genes. Similarly to receptors, coactivators and corepressors often serve pleiotropic functions, and Nrip1 (RIP140) is no exception, playing roles in animal development and physiology. At first sight, however, RIP140 is unusual in its ability to function either as a coactivator or as a corepressor, and also serve a cytoplasmic role. The functions of RIP140 in different tissues will be summarised together with its potential contribution to disease.

Negative regulation of estrogen signaling by ERβ and RIP140 in ovarian cancer cells

In hormone-dependent tissues such as breast and ovary, tumorigenesis is associated with an altered expression ratio between the two estrogen receptor (ER) subtypes. In this study, we investigated the effects of ERβ ectopic expression on 17β-estradiol (E2)-induced transactivation and cell proliferation in ERα-positive BG1 ovarian cancer cells. As expected, ERβ expression strongly decreased the mitogenic effect of E2, significantly reduced E2-dependent transcriptional responses (both on a stably integrated estrogen response element [ERE] reporter gene and on E2-induced mRNAs), and strongly enhanced the formation of ER heterodimers as evidenced by chromatin immunoprecipitation analysis. Inhibition by the ERα-selective ligand propyl pyrazole triol was less marked than with the pan-agonist (E2) or the ERβ-selective (8β-vinyl-estradiol) ligands, indicating that ERβ activation reinforced the inhibitory effects of ERβ. Interestingly, in E2-stimulated BG1 cells, ERβ was more efficient than ERα to regulate the expression of receptor-interacting protein 140 (RIP140), a major ERα transcriptional corepressor. In addition, we found that the RIP140 protein interacted better with ERβ than with ERα (both in vitro and in intact cells by fluorescence cross-correlation spectroscopy). Moreover, RIP140 recruitment on the stably integrated reporter ERE was increased upon ERβ overexpression, and ERβ activity was more sensitive to repression by RIP140. Finally, small interfering RNA-mediated knockdown of RIP140 expression abolished the repressive effect exerted by activated ERβ on the regulation of ERE-controlled transcription by estrogens. Altogether, these data demonstrate the inhibitory effects of ERβ on estrogen signaling in ovarian cancer cells and the key role that RIP140 plays in this phenomenon.