Complex regulation of LCoR signaling in breast cancer cells

Cell states and neighborhoods in distinct clinical stages of primary and metastatic esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) is a highly lethal cancer of the upper gastrointestinal tract with rising incidence in western populations. To decipher EAC disease progression and therapeutic response, we performed multiomic analyses of a cohort of primary and metastatic EAC tumors, incorporating single-nuclei transcriptomic and chromatin accessibility sequencing, along with spatial profiling. We identified tumor microenvironmental features previously described to associate with therapy response. We identified five malignant cell programs, including undifferentiated, intermediate, differentiated, epithelial-to-mesenchymal transition, and cycling programs, which were associated with differential epigenetic plasticity and clinical outcomes, and for which we inferred candidate transcription factor regulons. Furthermore, we revealed diverse spatial localizations of malignant cells expressing their associated transcriptional programs and predicted their significant interactions with microenvironmental cell types. We validated our findings in three external single-cell RNA-seq and three bulk RNA-seq studies. Altogether, our findings advance the understanding of EAC heterogeneity, disease progression, and therapeutic response.

The hsa-miR-3613-5p, a potential oncogene correlated with diagnostic and prognostic merits in kidney renal clear cell carcinoma

MicroRNA-3613 (hsa-miR-3613-5p), a biomarker with a dual role as an oncogenic or tumor suppressor, is associated with different types of cancer. This study aimed to determine the correlation between the hsa-miR-3613-5p gene expression and Kidney renal clear cell carcinoma (KIRC). Utilizing several bioinformatics tools, we examined the expression level and clinicopathological value of hsa-miR-3613-5p in patients with KIRC compared to normal tissues. Other bioinformatic measures, including survival analysis, diagnostic merit of hsa-miR-3613-5p, downstream target prediction, potential upstream lncRNAs, network construction, and functional enrichment analysis of hsa-miR-3613-5p, were performed. We observed that overexpression of hsa-miR-3613-5p in KIRC tissues had valuable diagnostic merit and was significantly correlated with the poor overall survival of KIRC patients. We also realized a correlation between abnormal expression of hsa-miR-3613-5p and several clinical parameters such as pathological stage, race, age, and histological grades in patients with KIRC. Moreover, we constructed the most potential regulatory network of hsa-miR-3613-5p in KIRC with 17 different axes, including four pseudogenes, two lncRNAs, and three mRNAs. Besides, we uncovered six variants in the mature form of hsa-miR-3613-5p. Finally, pathway enrichment analysis demonstrated that the top-ranked pathways for hsa-miR-3613-5p are cell cycle, cell adhesion molecules (CAMs), and hepatocellular carcinoma pathways. The present report suggests that the higher expression of hsa-miR-3613-5p is associated with the progression of KIRC. Therefore, it may be considered a valuable indicator for the early detection, risk stratification, and targeted treatment of patients with KIRC.

Estrogens receptors, nuclear coactivator 1 and ligand-dependent corepressor expression are altered early during induced ovarian follicular persistence in dairy cattle

Failure of ovulation can lead to follicular persistence, one of the main components of the pathogenesis of cystic ovarian disease (COD) in dairy cattle. Follicular persistence causes the permanence of a functional follicular structure in the ovary, which alters the cyclicity of the female and causes infertility. The aim of the present study was to evaluate the expression of estrogen receptors (ESR) 1 and 2, and the coregulatory proteins NCOA1, NRIP1 and LCOR by immunohistochemistry, in antral and preovulatory/persistent follicles in a model of follicular persistence induced by low levels of progesterone, to detect incipient changes during COD development, on the expected day of ovulation (P0) and after 5 (P5), 10 (P10) and 15 (P15) days of follicular persistence. Twenty-five Holstein cows were used, which were distributed in 5 groups: control group (n = 5), group P0 (n = 5), group P5 (n = 5), group P10 (n = 5), group P15 (n = 5). ESR1 expression was lower in antral follicles of the P5 (theca), P10 and P15 (theca and granulosa) groups relative to the control group (p < 0.05), and also lower in granulosa cells of persistent follicles of the P5, P10 and P15 groups than in dominant follicles of the control group (p < 0.05), without differences in theca cells. ESR2 expression showed no differences between groups. The ESR1:ESR2 balance favored ESR2 expression along the development of persistent follicles, as from 5 days of persistence (p < 0.05). NCOA1 expression was higher in granulosa cells of both antral and persistent follicles from the P0 group relative to the P5 and P10 groups, but showed no differences with the control and P15 groups (p < 0.05). Theca cells of antral and persistent follicles showed higher expression in the P0 and P15 groups in relation to the control, P5 and P10 groups (p < 0.05). No differences were detected for NRIP1 in antral, dominant and persistent follicles between groups. LCOR expression showed a decrease in granulosa cells of antral follicles from all persistence groups relative to the control group (p < 0.05). In theca cells, antral follicles of the P10 group showed lower LCOR expression than the control group (p < 0.05). LCOR expression was similar for dominant and persistent follicles. Considering that the ESR1:ESR2 balance favored ESR2 expression along the development of persistent follicles, as well as the decreased LCOR and NCOA1 expression, we may assume that, at the early stages of persistence, there is a negative regulation of ESR transcription. This coincides with the effects of estrogens through ESR on proliferation and apoptosis among other processes that favor follicular persistence. The results obtained provide relevant information in the knowledge of local events during the development of follicular persistence that could explain the failures in the reversion of the disease through hormonal treatments and the high recurrence rates reported for COD. In addition, it contributes to the study and identification of possible therapeutic targets, for the design of new treatments.

The Transcription Coregulator RIP140 Inhibits Cancer Cell Proliferation by Targeting the Pentose Phosphate Pathway

Cancer cells switch their metabolism toward glucose metabolism to sustain their uncontrolled proliferation. Consequently, glycolytic intermediates are diverted into the pentose phosphate pathway (PPP) to produce macromolecules necessary for cell growth. The transcription regulator RIP140 controls glucose metabolism in tumor cells, but its role in cancer-associated reprogramming of cell metabolism remains poorly understood. Here, we show that, in human breast cancer cells and mouse embryonic fibroblasts, RIP140 inhibits the expression of the gene-encoding G6PD, the first enzyme of the PPP. RIP140 deficiency increases G6PD activity as well as the level of NADPH, a reducing cofactor essential for macromolecule synthesis. Moreover, G6PD knock-down inhibits the gain of proliferation observed when RIP140 expression is reduced. Importantly, RIP140-deficient cells are more sensitive to G6PD inhibition in cell proliferation assays and tumor growth experiments. Altogether, this study describes a novel role for RIP140 in regulating G6PD levels, which links its effect on breast cancer cell proliferation to metabolic rewiring.

Challenges in Cell Fate Acquisition to Scid-Repopulating Activity from Hemogenic Endothelium of hiPSCs Derived from AML Patients Using Forced Transcription Factor Expression

The generation of human hematopoietic stem cells (HSCs) from human pluripotent stem cells (hPSCs) represents a major goal in regenerative medicine and is believed would follow principles of early development. HSCs arise from a type of endothelial cell called a “hemogenic endothelium” (HE), and human HSCs are experimentally detected by transplantation into SCID or other immune-deficient mouse recipients, termed SCID-Repopulating Cells (SRC). Recently, SRCs were detected by forced expression of seven transcription factors (TF) (ERG, HOXA5, HOXA9, HOXA10, LCOR, RUNX1, and SPI1) in hPSC-derived HE, suggesting these factors are deficient in hPSC differentiation to HEs required to generate HSCs. Here we derived PECAM-1-, Flk-1-, and VE-cadherin-positive endothelial cells that also lack CD45 expression (PFV^CD45−) which are solely responsible for hematopoietic output from iPSC lines reprogrammed from AML patients. Using HEs derived from AML patient iPSCs devoid of somatic leukemic aberrations, we sought to generate putative SRCs by the forced expression of 7TFs to model autologous HSC transplantation. The expression of 7TFs in hPSC-derived HE cells from an enhanced hematopoietic progenitor capacity was present in vitro, but failed to acquire SRC activity in vivo. Our findings emphasize the benefits of forced TF expression, along with the continued challenges in developing HSCs for autologous-based therapies from hPSC sources.

Nuclear Receptor Coregulators in Hormone-Dependent Cancers

Nuclear receptors (NRs) function collectively as a transcriptional signaling network that mediates gene regulatory actions to either maintain cellular homeostasis in response to hormonal, dietary and other environmental factors, or act as orphan receptors with no known ligand. NR complexes are large and interact with multiple protein partners, collectively termed coregulators. Coregulators are essential for regulating NR activity and can dictate whether a target gene is activated or repressed by a variety of mechanisms including the regulation of chromatin accessibility. Altered expression of coregulators contributes to a variety of hormone-dependent cancers including breast and prostate cancers. Therefore, understanding the mechanisms by which coregulators interact with and modulate the activity of NRs provides opportunities to develop better prognostic and diagnostic approaches, as well as novel therapeutic targets. This review aims to gather and summarize recent studies, techniques and bioinformatics methods used to identify distorted NR coregulator interactions that contribute as cancer drivers in hormone-dependent cancers.

RIP140 inhibits glycolysis-dependent proliferation of breast cancer cells by regulating GLUT3 expression through transcriptional crosstalk between hypoxia induced factor and p53

Glycolysis is essential to support cancer cell proliferation, even in the presence of oxygen. The transcriptional co-regulator RIP140 represses the activity of transcription factors that drive cell proliferation and metabolism and plays a role in mammary tumorigenesis. Here we use cell proliferation and metabolic assays to demonstrate that RIP140-deficiency causes a glycolysis-dependent increase in breast tumor growth. We further demonstrate that RIP140 reduces the transcription of the glucose transporter GLUT3 gene, by inhibiting the transcriptional activity of hypoxia inducible factor HIF-2α in cooperation with p53. Interestingly, RIP140 expression was significantly associated with good prognosis only for breast cancer patients with tumors expressing low GLUT3, low HIF-2α and high p53, thus confirming the mechanism of RIP140 anti-tumor activity provided by our experimental data. Overall, our work establishes RIP140 as a critical modulator of the p53/HIF cross-talk to inhibit breast cancer cell glycolysis and proliferation.

LCOR mediates interferon-independent tumor immunogenicity and responsiveness to immune-checkpoint blockade in triple-negative breast cancer

Ligand-dependent corepressor (LCOR) mediates normal and malignant breast stem cell differentiation. Cancer stem cells (CSCs) generate phenotypic heterogeneity and drive therapy resistance, yet their role in immunotherapy is poorly understood. Here we show that immune-checkpoint blockade (ICB) therapy selects for LCORlow CSCs with reduced antigen processing/presentation machinery (APM) driving immune escape and ICB resistance in triple-negative breast cancer (TNBC). We unveil an unexpected function of LCOR as a master transcriptional activator of APM genes binding to IFN-stimulated response elements (ISREs) in an IFN signaling-independent manner. Through genetic modification of LCOR expression, we demonstrate its central role in modulation of tumor immunogenicity and ICB responsiveness. In TNBC, LCOR associates with ICB clinical response. Importantly, extracellular vesicle (EV) Lcor-messenger RNA therapy in combination with anti-PD-L1 overcame resistance and eradicated breast cancer metastasis in preclinical models. Collectively, these data support LCOR as a promising target for enhancement of ICB efficacy in TNBC, by boosting of tumor APM independently of IFN.

A Truncated NRIP1 Mutant Amplifies Microsatellite Instability of Colorectal Cancer by Regulating MSH2/MSH6 Expression, and Is a Prognostic Marker of Stage III Tumors

Simple Summary

The alteration of mismatch repair (MMR) genes leads to microsatellite instability and plays a key role in colorectal cancer (CRC) pathogenesis and prognosis. The transcription factor NRIP1 is involved in intestinal tumorigenesis and is a good prognostic marker in CRC. In this study, we demonstrate that NRIP1 induces MSH2 and MSH6 MMR gene transcription and reduces microsatellite instability. A dominant-negative truncated NRIP1 mutant amplifies the MMR-deficient phenotype and appears as a key player in MSI-driven tumorigenesis since it significantly correlates with a short overall survival of patients with advanced CRC, especially MLH1-deficient ones.

Abstract

Microsatellite instability (MSI) is related to the alteration of mismatch repair (MMR) genes and plays a key role in colorectal cancer (CRC) pathogenesis. We previously reported that the transcription factor Nuclear Receptor Interacting Protein 1 (NRIP1) is involved in sporadic intestinal tumorigenesis. The aim of this study was to decipher its role in MSI CRC. By using different mouse models and engineered cell lines, we demonstrated that NRIP1 increased MSH2 and MSH6 MMR gene transcription and mRNA/protein levels. In human CRC cells, NRIP1 expression was associated with decreased MSI and the hypermutator phenotype, and with resistance to chemotherapy drugs. Using a cohort of 194 CRC patients, we detected in 22% of the cases a MSI-induced frameshift mutation in the NRIP1 coding sequence. This genetic alteration generates a truncated protein with a dominant negative activity that increased human CRC cell proliferation and impaired the regulation of MSH2 and MSH6 gene expression. Moreover, the NRIP1 mutant correlated with a decreased overall survival of patients with advanced CRC, especially when MLH1-deficient. By decreasing the expression of MSH2 and MSH6 gene expression, the NRIP1 variant may amplify MLH1-dependent CRC progression and behave as a new prognostic marker of advanced MSI CRC.

The Expression of NRIP1 and LCOR in Endometrioid Endometrial Cancer

BACKGROUND

The aim of the study was to analyze the expression of nuclear receptor interacting protein 1 (NRIP1) and its partner ligand-dependent nuclear receptor co-repressor (LCOR) in endometrioid endometrial cancer and to investigate their association with estrogen receptor (ER), progesterone receptor (PR), Ki-67, clinicopathological parameters and patient survival.

MATERIALS AND METHODS

Immunohistochemical evaluation was carried out to investigate the subcellular expression of NRIP1 and LCOR in endometrioid endometrial cancer samples. Statistical analysis was used to identify the correlations of NRIP1 and LCOR expression with clinicopathological variables and to estimate the survival rates.

RESULTS

Endometrial cancer tissues exhibited higher expression of NRIP1 and LCOR in comparison with the normal tissues. Cytoplasmic LCOR expression was positively associated with ER and PR expression, while cytoplasmic NRIP1 expression was positively associated with ER expression. Moreover, cytoplasmic expression of NRIP1 was positively associated with Ki-67.

CONCLUSION

Our study demonstrated that high cytoplasmic expression of LCOR may predict a longer overall survival of patients with endometrioid endometrial cancer. Patients with tumors expressing low levels of LCOR showed a worse survival compared to those expressing high levels.

Cytoplasmic LXR expression is an independent marker of poor prognosis for patients with early stage primary breast cancer

Purpose

The aim of this study was to investigate the expression of liver X receptors α/β (LXR) in primary breast cancer (BC) tissues and to analyze its correlations with clinicopathological parameters including patient survival.

Methods

In a well-characterized cohort of 305 primary BC, subcellular distribution of LXR was evaluated by immunohistochemistry. Correlations with clinicopathological characteristics as well as with patient outcome were analyzed.

Results

LXR was frequently localized in both nuclei and cytoplasms of BC cells, with stronger staining in nuclei. Total and nuclear LXR expression was positively correlated with ER and PR status. Overall survival analysis demonstrated that cytoplasmic LXR was significantly correlated with poor survival and appeared as an independent marker of poor prognosis, in stage I but not in stage II–III tumors

Conclusion

Altogether, these data suggest that cytoplasmic LXR could be defined as a prognostic marker in early stage primary BC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03670-y.

An R package for generic modular response analysis and its application to estrogen and retinoic acid receptor crosstalk

Modular response analysis (MRA) is a widely used inference technique developed to uncover directions and strengths of connections in molecular networks under a steady-state condition by means of perturbation experiments. We devised several extensions of this methodology to search genomic data for new associations with a biological network inferred by MRA, to improve the predictive accuracy of MRA-inferred networks, and to estimate confidence intervals of MRA parameters from datasets with low numbers of replicates. The classical MRA computations and their extensions were implemented in a freely available R package called aiMeRA (https://github.com/bioinfo-ircm/aiMeRA/). We illustrated the application of our package by assessing the crosstalk between estrogen and retinoic acid receptors, two nuclear receptors implicated in several hormone-driven cancers, such as breast cancer. Based on new data generated for this study, our analysis revealed potential cross-inhibition mediated by the shared corepressors NRIP1 and LCoR. We designed aiMeRA for non-specialists and to allow biologists to perform their own analyses.

Effect of glucose deprivation on the expression of genes encoding glucocorticoid receptor and some related factors in ERN1-knockdown U87 glioma cells

OBJECTIVE

The aim of the present study was to examine the effect of glucose deprivation on the expression of genes encoded glucocorticoid receptor (NR3C1) and some related proteins (NR3C2, AHR, NRIP1, NNT, ARHGAP35, SGK1, and SGK3) in U87 glioma cells in response to inhibition of endoplasmic reticulum stress signaling mediated by ERN1/IRE1 (endoplasmic reticulum to nucleus signaling 1/inositol requiring enzyme 1) for evaluation of their possible significance in the control of glioma growth through endoplasmic reticulum stress signaling mediated by IRE1 and glucose deprivation.

METHODS

The expression of NR3C1, NR3C2, AHR, NRIP1, NNT, ARHGAP35, SGK1, and SGK3 genes in U87 glioma cells transfected by empty vector pcDNA3.1 (control cells) and cells without ERN1 signaling enzyme function (transfected by dnERN1) under glucose deprivation was studied by real time quantitative polymerase chain reaction.

RESULTS

It was shown that the expression level of NR3C2, AHR, SGK1, SGK3, and NNT genes was up-regulated in control U87 glioma cells under glucose deprivation condition in comparison with the control cells growing with glucose. At the same time, the expression of NRIP1 gene is down-regulated in these glioma cells under glucose deprivation, but NR3C1 and ARHGAP35 genes was resistant to this experimental condition. We also showed that inhibition of ERN1 signaling enzyme function significantly modified the response of most studied gene expressions to glucose deprivation condition. Thus, effect of glucose deprivation on the expression level of NR3C2, AHR, and SGK1 genes was significantly stronger in ERN1 knockdown U87 glioma cells since the expression of NNT gene was resistant to glucose deprivation condition. Moreover, the inhibition of ERN1 enzymatic activities in U87 glioma cells led to up-regulation of ARHGAP35 gene expression and significant down-regulation of the expression of SGK3 gene in response to glucose deprivation condition.

CONCLUSIONS

Results of this study demonstrated that glucose deprivation did not change the expression level of NR3C1 gene but it significantly affected the expression of NR3C2, AHR, NRIP, SGK1, SGK3, and NNT genes in vector-transfected U87 glioma cells in gene specific manner and possibly contributed to the control of glioma growth since the expression of most studied genes in glucose deprivation condition was significantly dependent on the functional activity of IRE1 signaling enzyme.

Regulation of LCoR and RIP140 expression in cervical intraepithelial neoplasia and correlation with CIN progression and dedifferentiation

Purpose

Ligand-dependent corepressor (LCoR) and receptor-interacting protein 140 (RIP140/NRIP1) play an important role in the regulation of multiple oncogenic signaling pathways and the development of cancer. LCoR and RIP140 form a nuclear complex in breast cancer cells and are of prognostic value in further prostate and cervical cancer. The purpose of this study was to analyze the regulation of these proteins in the development of cervical intraepithelial neoplasia (CIN I–III).

Methods

Immunohistochemical analysis was obtained to quantify RIP140 and LCoR expression in formalin-fixed paraffin embedded tissue sections of cervical intraepithelial neoplasia samples. Tissue (n = 94) was collected from patients treated in the Department of Gynecology and Obstetrics, Ludwig-Maximilians-University of Munich, Germany, between 2002 and 2014. Correlations of expression levels with clinical outcome were carried out to assess for prognostic relevance in patients with CIN2 progression. Kruskal–Wallis test and Mann–Whitney U test were used for data analysis.

Results

Nuclear LCoR overexpression correlates significantly with CIN II progression. Nuclear RIP140 expression significantly increases and nuclear LCoR expression decreases with higher grading of cervical intraepithelial neoplasia. Cytoplasmic RIP140 expression is significantly higher in CIN III than in CIN I or CIN II.

Conclusion

A decrease of nuclear LCoR expression in line with an increase of dedifferentiation of CIN can be observed. Nuclear LCoR overexpression correlates with CIN II progression indicating a prognostic value of LCoR in cervical intraepithelial neoplasia. Nuclear and cytoplasmic RIP140 expression increases significantly with higher grading of cervical intraepithelial neoplasia underlining its potential role in the development of pre-cancerous lesions. These findings support the relevance of LCoR and RIP140 in the tumorigenesis indicating a possible role of LCoR and RIP140 as targets for novel therapeutic approaches in cervical intraepithelial neoplasia and cervical cancer.

Cholesterol, Oxysterols and LXRs in Breast Cancer Pathophysiology

Breast cancer is the most frequent cancer among women. In 2018, it is estimated that 627,000 women died from breast cancer. This is approximately 15% of all cancer deaths among women (WHO 2018). Breast cancer is a multifactorial chronic disease. While important progress has been made to treat patients, many questions regarding aspects of this disease relating to carcinogenesis are still open. During carcinogenesis, cells exhibit cholesterol homeostasis deregulation. This results in an accumulation of intracellular cholesterol, which is required to sustain their high growth rate. Cholesterol efflux and influx are two metabolic pathways that are necessary to prevent cholesterol accumulation in the cells. Liver X receptors (LXRs) are nuclear receptors that, upon activation, induce the expression of ABC transporters, responsible for promoting cholesterol efflux, and the expression of IDOL (inducible degrader of low-density lipoprotein receptor), in charge of reducing cholesterol influx. Oxysterols, oxygenated derivatives of cholesterol formed through different pathways, have been discovered as LXR-specific ligands. Some oxysterols are involved in tumor formation while others are considered anti-tumor agents. In the present review, we discuss the involvement of cholesterol, oxysterols and LXRs in breast cancer pathophysiology, with an emphasis on the biological effects of LXR ligands.

Cytoplasmic and Nuclear Forms of Thyroid Hormone Receptor β1 Are Inversely Associated with Survival in Primary Breast Cancer

The aim of this study was to investigate the expression of thyroid hormone receptor β1 (THRβ1) by immunohistochemistry in breast cancer (BC) tissues and to correlate the results with clinico-biological parameters. In a well-characterized cohort of 274 primary BC patients, THRβ1 was widely expressed with a predominant nuclear location, although cytoplasmic staining was also frequently observed. Both nuclear and cytoplasmic THRβ1 were correlated with high-risk BC markers such as human epidermal growth factor receptor 2 (HER2), Ki67 (also known as MKI67), prominin-1 (CD133), and N-cadherin. Overall survival analysis demonstrated that cytoplasmic THRβ1 was correlated with favourable survival (p = 0.015), whereas nuclear THRβ1 had a statistically significant correlation with poor outcome (p = 0.038). Interestingly, in our cohort, nuclear and cytoplasmic THRβ1 appeared to be independent markers either for poor (p = 0.0004) or for good (p = 0.048) prognosis, respectively. Altogether, these data indicate that the subcellular expression of THRβ1 may play an important role in oncogenesis. Moreover, the expression of nuclear THRβ1 is a negative outcome marker, which may help to identify high-risk BC subgroups.

Construction of miRNA-target networks using microRNA profiles of CVB3-infected HeLa cells

MicroRNAs (miRNAs) play an important role in regulating gene expression in multiple biological processes and diseases. Thus, to understand changes in miRNA during CVB3 infection, specific miRNA expression profiles were investigated at 3 h, 6 h, and 9 h postinfection in HeLa cells by small-RNA high-throughput sequencing. Biological implications of 68 differentially expressed miRNAs were analyzed through GO and KEGG pathways. Interaction networks between 34 known highly differentially expressed miRNAs and targets were constructed by mirDIP and Navigator. The predicted targets showed that FAM135A, IKZF2, PLAG1, ZNF148, PHC3, LCOR and DYRK1A, which are associated with cellular differentiation and transcriptional regulation, were recognized by 8 miRNAs or 9 miRNAs through interactional regulatory networks. Seven target genes were confirmed by RT-qPCR. The results showed that the expression of DYRK1A, FAM135A, PLAG1, ZNF148, and PHC3 were obviously inhibited at 3 h, 6 h, and 9 h postinfection. The expression of LCOR did not show a significant change, and the expression of IKZF2 increased gradually with prolonged infection time. Our findings improve the understanding of the pathogenic mechanism of CVB3 infection on cellular differentiation and development through miRNA regulation, which has implications for interventional approaches to CVB3-infection therapy. Our results also provide a new method for screening target genes of microRNA regulation in virus-infected cells.

ER-Negative Breast Cancer Is Highly Responsive to Cholesterol Metabolite Signalling

Interventions that alter cholesterol have differential impacts on hormone receptor positive- and negative-breast cancer risk and prognosis. This implies differential regulation or response to cholesterol within different breast cancer subtypes. We evaluated differences in side-chain hydroxycholesterol and liver X nuclear receptor signalling between Oestrogen Receptor (ER)-positive and ER-negative breast cancers and cell lines. Cell line models of ER-positive and ER-negative disease were treated with Liver X Receptor (LXR) ligands and transcriptional activity assessed using luciferase reporters, qPCR and MTT. Publicly available datasets were mined to identify differences between ER-negative and ER-positive tumours and siRNA was used to suppress candidate regulators. Compared to ER-positive breast cancer, ER-negative breast cancer cells were highly responsive to LXR agonists. In primary disease and cell lines LXRA expression was strongly correlated with its target genes in ER-negative but not ER-positive disease. Expression of LXR’s corepressors (NCOR1, NCOR2 and LCOR) was significantly higher in ER-positive disease relative to ER-negative, and their knock-down equalized sensitivity to ligand between subtypes in reporter, gene expression and viability assays. Our data support further evaluation of dietary and pharmacological targeting of cholesterol metabolism as an adjunct to existing therapies for ER-negative and ER-positive breast cancer patients.

Prognostic relevance of RIP140 and ERβ expression in unifocal versus multifocal breast cancers: a preliminary report

The aim of this study was to investigate the expression of two nuclear receptor transcriptional coregulators, namely RIP140 (receptor-interacting protein of 140 kDa) and LCoR (ligand-dependent corepressor) in unifocal versus multifocal breast cancers. The expression of these two proteins was analyzed by immunohistochemistry in a matched-pair cohort of 21 unifocal and 21 multifocal breast tumors. The expression of the two estrogen receptors (ERα and ERβ) was studied in parallel. RIP140 and LCoR levels appeared lower in unifocal tumors compared to multifocal samples (decreased of immune-reactive scores and reduced number of high expressing cells). In both tumor types, RIP140 and LCoR expression was correlated with each other and with expression of ERβ. Very interestingly, the expression of RIP140, LCoR, and ERβ was inversely correlated with overall survival only for the unifocal group. The negative correlation with overall and recurrence free survival was more pronounced in patients whose unifocal tumors expressed high levels of both RIP140 and ERβ. Altogether, this preliminary report indicates that the ERβ/RIP140 signaling is altered in unifocal breast cancers and correlated with patient outcome. Further investigation is needed to decipher the molecular mechanisms and the biological relevance of this deregulation.

Importance of RIP140 and LCoR Sub-Cellular Localization for Their Association With Breast Cancer Aggressiveness and Patient Survival

New markers are needed to improve diagnosis and to personalize treatments for patients with breast cancer (BC). Receptor-interacting protein of 140 kDa (RIP140) and ligand-dependent corepressor (LCoR), two transcriptional co-regulators of estrogen receptors, strongly interact in BC cells. Although their role in cancer progression has been outlined in the last few years, their function in BC has not been elucidated yet. In this study, we investigated RIP140 and LCoR localization (cytoplasm vs nucleus) in BC samples from a well-characterized cohort of patients (n = 320). RIP140 and LCoR were expressed in more than 80% of tumors, (predominantly in the cytoplasm), and the two markers were highly correlated. Expression of RIP140 and LCoR in the nucleus was negatively correlated with tumor size. Conversely, RIP140 and LCoR cytoplasmic expression strongly correlated with expression of two tumor aggressiveness markers: N-cadherin and CD133 (epithelial mesenchymal transition and cancer stem cell markers, respectively). Finally, high RIP140 nuclear expression was significantly correlated with longer overall survival, whereas high total or cytoplasmic expression of RIP140 was associated with shorter disease-free survival. Our study strongly suggests that the role of RIP140 and LCoR in BC progression could vary according to their prevalent sub-cellular localization, with opposite prognostic values for nuclear and cytoplasmic expression. The involvement in BC progression/invasiveness of cytoplasmic RIP140 could be balanced by the anti-tumor action of nuclear RIP140, thus explaining the previous contradictory findings about its role in BC.

RIP140 and LCoR expression in gastrointestinal cancers

The transcription coregulators RIP140 and LCoR are part of a same complex which controls the activity of various transcription factors and cancer cell proliferation. In this study, we have investigated the expression of these two genes in human colorectal and gastric cancers by immunohistochemistry. In both types of tumors, the levels of RIP140 and LCoR appeared highly correlated. Their expression tended to decrease in colorectal cancer as compared to adjacent normal tissues but was found higher in gastric cancer as compared to normal stomach. RIP140 and LCoR expression correlated with TNM and tumor differentiation. Significant correlations were observed with expression levels of key proteins involved in tumor progression and invasion namely E-cadherin and Cyclooxygenase-2. Survival analysis showed that patients with LCoR^low/RIP140^high colorectal tumors have a significant prolonged overall and disease-free survival. In gastric cancer, high LCoR expression was identified as an independent marker of poor prognosis suggesting a key role in this malignancy. Altogether, these results demonstrate that RIP140 and LCoR have a prognostic relevance in gastrointestinal cancers and could represent new potential biomarkers in these tumors.

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.

Expression and role of nuclear receptor coregulators in colorectal cancer

Colorectal cancer (CRC) is one of the most common human cancers and the cause of about 700000 deaths per year worldwide. Deregulation of the WNT/β-catenin pathway is a key event in CRC initiation. This pathway interacts with other nuclear signaling pathways, including members of the nuclear receptor superfamily and their transcription coregulators. In this review, we provide an overview of the literature dealing with the main coactivators (NCoA-1 to 3, NCoA-6, PGC1-α, p300, CREBBP and MED1) and corepressors (N-CoR1 and 2, NRIP1 and MTA1) of nuclear receptors and summarize their links with the WNT/β-catenin signaling cascade, their expression in CRC and their role in intestinal physiopathology.