Gene Summary

Gene:NR5A2; nuclear receptor subfamily 5, group A, member 2
Aliases: B1F, CPF, FTF, B1F2, LRH1, LRH-1, FTZ-F1, hB1F-2, FTZ-F1beta
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:nuclear receptor subfamily 5 group A member 2
Source:NCBIAccessed: 25 June, 2015


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 25 June 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 25 June, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (3)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: NR5A2 (cancer-related)

Bayrer JR, Mukkamala S, Sablin EP, et al.
Silencing LRH-1 in colon cancer cell lines impairs proliferation and alters gene expression programs.
Proc Natl Acad Sci U S A. 2015; 112(8):2467-72 [PubMed] Free Access to Full Article Related Publications
Colorectal cancers (CRCs) account for nearly 10% of all cancer deaths in industrialized countries. Recent evidence points to a central role for the nuclear receptor liver receptor homolog-1 (LRH-1) in intestinal tumorigenesis. Interaction of LRH-1 with the Wnt/β-catenin pathway, highly active in a critical subpopulation of CRC cells, underscores the importance of elucidating LRH-1's role in this disease. Reduction of LRH-1 diminishes tumor burden in murine models of CRC; however, it is not known whether LRH-1 is required for tumorigenesis, for proliferation, or for both. In this work, we address this question through shRNA-mediated silencing of LRH-1 in established CRC cell lines. LRH-1 mRNA knockdown results in significantly impaired proliferation in a cell line highly expressing the receptor and more modest impairment in a cell line with moderate LRH-1 expression. Cell-cycle analysis shows prolongation of G0/G1 with LRH-1 silencing, consistent with LRH-1 cell-cycle influences in other tissues. Cluster analysis of microarray gene expression demonstrates significant genome wide alterations with major effects in cell-cycle regulation, signal transduction, bile acid and cholesterol metabolism, and control of apoptosis. This study demonstrates a critical proproliferative role for LRH-1 in established colon cancer cell lines. LRH-1 exerts its effects via multiple signaling networks. Our results suggest that selected CRC patients could benefit from LRH-1 inhibitors.

Doan TB, Eriksson NA, Graham D, et al.
Breast cancer prognosis predicted by nuclear receptor-coregulator networks.
Mol Oncol. 2014; 8(5):998-1013 [PubMed] Related Publications
Although molecular signatures based on transcript expression in breast cancer samples have provided new insights into breast cancer classification and prognosis, there are acknowledged limitations in current signatures. To provide rational, pathway-based signatures of disrupted physiology in cancer tissues that may be relevant to prognosis, this study has directly quantitated changed gene expression, between normal breast and cancer tissue, as a basis for signature development. The nuclear receptor (NR) family of transcription factors, and their coregulators, are fundamental regulators of every aspect of metazoan life, and were rigorously quantified in normal breast tissues and ERα positive and ERα negative breast cancers. Coregulator expression was highly correlated with that of selected NR in normal breast, particularly from postmenopausal women. These associations were markedly decreased in breast cancer, and the expression of the majority of coregulators was down-regulated in cancer tissues compared with normal. While in cancer the loss of NR-coregulator associations observed in normal breast was common, a small number of NR (Rev-ERBβ, GR, NOR1, LRH-1 and PGR) acquired new associations with coregulators in cancer tissues. Elevated expression of these NR in cancers was associated with poorer outcome in large clinical cohorts, as well as suggesting the activation of ERα -related, but ERα-independent, pathways in ERα negative cancers. In addition, the combined expression of small numbers of NR and coregulators in breast cancer was identified as a signature predicting outcome in ERα negative breast cancer patients, not linked to proliferation and with predictive power superior to existing signatures containing many more genes. These findings highlight the power of predictive signatures derived from the quantitative determination of altered gene expression between normal breast and breast cancers. Taken together, the findings of this study identify networks of NR-coregulator associations active in normal breast but disrupted in breast cancer, and moreover provide evidence that signatures based on NR networks disrupted in cancer can provide important prognostic information in breast cancer patients.

Lin Q, Aihara A, Chung W, et al.
LRH1 promotes pancreatic cancer metastasis.
Cancer Lett. 2014; 350(1-2):15-24 [PubMed] Related Publications
The transcriptional factor liver receptor homolog 1 (LRH1) regulates pancreatic development, and may participate in pancreatic oncogenesis through activation of growth factor signaling transduction cascades. We measured transcriptional activity of β-catenin in response to LRH1 stimulation by a Topflash reporter assay. The pancreatic cancer (PC) phenotype was then characterized by cell migration, wound healing, invasion, and sphere formation in vitro, as well as tumor formation and distant metastatic spread in vivo. We compared results between vector control and LRH1-overexpressing stable PC cell lines. In addition, tumor burden, angiogenesis, histologic characteristics, and hepatic spread were assessed in orthotopic and experimental liver metastatic murine models. Expression of downstream LRH1 related genes was evaluated by Western blot and immunohistochemistry in PC cell lines and human tumor specimens. Specific inhibition of LRH1 expression and function was accomplished by shRNAs "knockdown" experiments. It was found that LRH1 enhanced transcriptional activity of β-catenin and the expression of downstream target genes (c-Myc, MMP2/9), as well as promoted migration, wound healing, invasion, and sphere formation of PC cell lines. Specific inhibition of LRH1 by shRNAs reduced cell migration, invasion, sphere formation and expression of c-Myc and MMP2/9 target genes. Mice injected with LRH1 overexpressing stable PC cells developed tumors with increased size and exhibited striking hepatic metastatic spread. More important, LRH1 was overexpressed in PC tumors compared to adjacent normal pancreas. Our findings demonstrate that LRH1 overexpression is associated with increased PC growth and metastatic spread, indicating that LRH1-targeted therapy could inhibit tumor progression.

Lazarus KA, Brown KA, Young MJ, et al.
Conditional overexpression of liver receptor homolog-1 in female mouse mammary epithelium results in altered mammary morphogenesis via the induction of TGF-β.
Endocrinology. 2014; 155(5):1606-17 [PubMed] Related Publications
Liver receptor homolog-1 (LRH-1) is an orphan nuclear receptor that belongs to the NR5A subgroup of nuclear receptors. LRH-1 induces key genes to regulate metabolic process, ovarian function, cancer cell proliferation, and steroidogenesis. In the breast, LRH-1 modulates and synergizes with endogenous estrogen signaling to promote breast cancer cell proliferation. We used small interfering RNA knockdown strategies to deplete LRH-1 in breast cancer cells and followed with microarray analysis to identify LRH-1-dependent mechanisms. We identified key genes involved in TGF-β signaling to be highly responsive to LRH-1 knockdown. This relationship was validated in 2 breast cancer cell lines overexpressing LRH-1 in vitro and in a novel transgenic mouse with targeted LRH-1 overexpression in mammary epithelial cells. Notably, TGF-β signaling was activated in LRH-1-overexpressing breast cancer cells and mouse mammary glands. Further analyses of mammary gross morphology revealed a significant reduction in mammary lateral budding after LRH-1 overexpression. These findings suggest that the altered mammary morphogenesis in LRH-1 transgenic animals is mediated via enhanced TGF-β expression. The regulation of TGF-β isoforms and SMAD2/3-mediated downstream signaling by LRH-1 also implicates a potential contribution of LRH-1 in breast cancer. Collectively, these data demonstrate that LRH-1 regulates TGF-β expression and downstream signaling in mouse mammary glands.

Bianco S, Brunelle M, Jangal M, et al.
LRH-1 governs vital transcriptional programs in endocrine-sensitive and -resistant breast cancer cells.
Cancer Res. 2014; 74(7):2015-25 [PubMed] Related Publications
Tumor characteristics are decisive in the determination of treatment strategy for patients with breast cancer. Patients with estrogen receptor α (ERα)-positive breast cancer can benefit from long-term hormonal treatment. Nonetheless, the majority of patients will develop resistance to these therapies. Here, we investigated the role of the nuclear receptor liver receptor homolog-1 (LRH-1, NR5A2) in antiestrogen-sensitive and -resistant breast cancer cells. We identified genome-wide LRH-1-binding sites using ChIP-seq (chromatin immunoprecipitation sequencing), uncovering preferential binding to regions distal to transcriptional start sites. We further characterized these LRH-1-binding sites by integrating overlapping layers of specific chromatin marks, revealing that many LRH-1-binding sites are active and could be involved in long-range enhancer-promoter looping. Combined with transcriptome analysis of LRH-1-depleted cells, these results show that LRH-1 regulates specific subsets of genes involved in cell proliferation in antiestrogen-sensitive and antiestrogen-resistant breast cancer cells. Furthermore, the LRH-1 transcriptional program is highly associated with a signature of poor outcome and high-grade breast cancer tumors in vivo. Herein, we report the genome-wide location and molecular function of LRH-1 in breast cancer cells and reveal its therapeutic potential for the treatment of breast cancers, notably for tumors resistant to treatments currently used in therapies.

Lin Q, Aihara A, Chung W, et al.
LRH1 as a driving factor in pancreatic cancer growth.
Cancer Lett. 2014; 345(1):85-90 [PubMed] Free Access to Full Article Related Publications
Liver receptor homolog 1 (LRH1), directs the development and differentiation of embryonic pancreas, and is overexpressed in pancreatic cancer (PC). We hypothesized that LRH1 promotes PC growth. Cell proliferation and tumorigenicity in nude mice were compared between empty vector-transfected (control) and stable LRH1-overexpressed PC cell lines. The subsequent tumor burden, vasculature development, and histologic features were evaluated. LRH1 overexpression enhanced the expression of downstream target genes (cyclin D1/E1) and stimulated cell proliferation in PC cell lines. LRH1 upregulated cyclin E1 truncated T1/T2 isoforms expression which may occur through ERα-calpain1 signaling. Compared with the control, LRH1 overexpressing stable cells generated tumors with increased weight, proliferation index and enhanced angiogenesis. Cyclin D1/E1 and calpain1 were overexpressed in human PC tumors compared to adjacent normal pancreas. These observations demonstrate that LRH1 promotes PC growth and angiogenesis, suggesting that LRH1 is a driving factor in tumorigenesis and may serve as a potential therapeutic target.

Liu R, Yang M, Meng Y, et al.
Tumor-suppressive function of miR-139-5p in esophageal squamous cell carcinoma.
PLoS One. 2013; 8(10):e77068 [PubMed] Free Access to Full Article Related Publications
Recent studies have demonstrated the possible function of miR-139-5p in tumorigenesis. However, the exact mechanism of miR-139-5p in cancer remains unclear. In this study, the association of miR-139-5p expression with esophageal squamous cell carcinoma (ESCC) was evaluated in 106 pairs of esophageal cancer and adjacent non-cancerous tissue from ESCC patients. The tumor suppressive features of miR-139-5p were measured by evaluating cell proliferation and cell cycle state, migratory activity and invasion capability, as well as apoptosis. Luciferase reporter assay and Western blot analysis were performed to determine the target gene regulated by miR-139-5p. The mRNA level of NR5A2, the target gene of miR-139-5p, was determined in ESCC patients. Results showed that reduced miR-139-5p level was associated with lymph node metastases of ESCC. MiR-139-5p was investigated to induce cell cycle arrest in the G0/G1 phase and to suppress the invasive capability of esophageal carcinoma cells by targeting the 3'UTR of oncogenic NR5A2. Cyclin E1 and MMP9 were confirmed to participate in cell cycle arrest and invasive suppression induced by NR5A2, respectively. Pearson correlation analysis further confirmed the significantly negative correlation between miR-139-5p and NR5A2 expression. The results suggest that miR-139-5p exerts a growth- and invasiveness-suppressing function in human ESCCs, which demonstrates that miR-139-5p is a potential biomarker for early diagnosis and prognosis and is a therapeutic target for ESCC.

Knower KC, Chand AL, Eriksson N, et al.
Distinct nuclear receptor expression in stroma adjacent to breast tumors.
Breast Cancer Res Treat. 2013; 142(1):211-23 [PubMed] Related Publications
The interaction between breast tumor epithelial and stromal cells is vital for initial and recurrent tumor growth. While breast cancer-associated stromal cells provide a favorable environment for proliferation and metastasis, the molecular mechanisms contributing to this process are not fully understood. Nuclear receptors (NRs) are intracellular transcription factors that directly regulate gene expression. Little is known about the status of NRs in cancer-associated stroma. Nuclear Receptor Low-Density Taqman Arrays were used to compare the gene expression profiles of all 48 NR family members in a collection of primary cultured cancer-associated fibroblasts (CAFs) obtained from estrogen receptor (ER)α positive breast cancers (n = 9) and normal breast adipose fibroblasts (NAFs) (n = 7). Thirty-three of 48 NRs were expressed in both the groups, while 11 NRs were not detected in either. Three NRs (dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1 (DAX-1); estrogen-related receptor beta (ERR-β); and RAR-related orphan receptor beta (ROR-β)) were only detected in NAFs, while one NR (liver receptor homolog-1 (LRH-1)) was unique to CAFs. Of the NRs co-expressed, four were significantly down-regulated in CAFs compared with NAFs (RAR-related orphan receptor-α (ROR-α); Thyroid hormone receptor-β (TR-β); vitamin D receptor (VDR); and peroxisome proliferator-activated receptor-γ (PPAR-γ)). Quantitative immunohistochemistry for LRH-1, TR-β, and PPAR-γ proteins in stromal fibroblasts from an independent panel of breast cancers (ER-positive (n = 15), ER-negative (n = 15), normal (n = 14)) positively correlated with mRNA expression profiles. The differentially expressed NRs identified in tumor stroma are key mediators in aromatase regulation and subsequent estrogen production. Our findings reveal a distinct pattern of NR expression that therefore fits with a sustained and increased local estrogen microenvironment in ER-positive tumors. NRs in CAFs may provide a new avenue for the development of intratumoral-targeted therapies in breast cancer.

Naumov VA, Generozov EV, Zaharjevskaya NB, et al.
Genome-scale analysis of DNA methylation in colorectal cancer using Infinium HumanMethylation450 BeadChips.
Epigenetics. 2013; 8(9):921-34 [PubMed] Free Access to Full Article Related Publications
Illumina's Infinium HumanMethylation450 BeadChip arrays were used to examine genome-wide DNA methylation profiles in 22 sample pairs from colorectal cancer (CRC) and adjacent tissues and 19 colon tissue samples from cancer-free donors. We show that the methylation profiles of tumors and healthy tissue samples can be clearly distinguished from one another and that the main source of methylation variability is associated with disease status. We used different statistical approaches to evaluate the methylation data. In general, at the CpG-site level, we found that common CRC-specific methylation patterns consist of at least 15,667 CpG sites that were significantly different from either adjacent healthy tissue or tissue from cancer-free subjects. Of these sites, 10,342 were hypermethylated in CRC, and 5,325 were hypomethylated. Hypermethylated sites were common in the maximum number of sample pairs and were mostly located in CpG islands, where they were significantly enriched for differentially methylated regions known to be cancer-specific. In contrast, hypomethylated sites were mostly located in CpG shores and were generally sample-specific. Despite the considerable variability in methylation data, we selected a panel of 14 highly robust candidates showing methylation marks in genes SND1, ADHFE1, OPLAH, TLX2, C1orf70, ZFP64, NR5A2, and COL4A. This set was successfully cross-validated using methylation data from 209 CRC samples and 38 healthy tissue samples from The Cancer Genome Atlas consortium (AUC = 0.981 [95% CI: 0.9677-0.9939], sensitivity = 100% and specificity = 82%). In summary, this study reports a large number of loci with novel differential methylation statuses, some of which may serve as candidate markers for diagnostic purposes.

Lanzino M, Maris P, Sirianni R, et al.
DAX-1, as an androgen-target gene, inhibits aromatase expression: a novel mechanism blocking estrogen-dependent breast cancer cell proliferation.
Cell Death Dis. 2013; 4:e724 [PubMed] Free Access to Full Article Related Publications
Sexual hormones, estrogens and androgens, determine biological response in a tissue- and gender-specific manner and have a pivotal role in endocrine-mediated tumorigenesis. In situ estrogen production by aromatase is a critical determinant for breast cancer growth and progression. On the contrary, clinical and in vitro studies indicate that androgens have a protective role in mammary carcinogenesis. Here, we demonstrated, in hormone-dependent breast cancer cells, the existence of a functional interplay between the androgen receptor (AR), the orphan nuclear receptor DAX-1 and the aromatase enzyme involved in the inhibition of the estrogen-dependent breast cancer cell proliferation exerted by androgen signaling. Indeed, our results revealed, in MCF-7 cells, that ligand-activated AR induces the expression of the orphan nuclear receptor DAX-1 by direct binding to a newly identified androgen-response-element within the DAX-1 proximal promoter. In turn, androgen-induced DAX-1 is recruited, in association with the corepressor N-CoR, within the SF-1/LRH-1 containing region of the aromatase promoter, thereby repressing aromatase expression and activity. In elucidating a novel mechanism by which androgens, through DAX-1, inhibit aromatase expression in breast cancer cell lines, these findings reinforce the theory of androgen- opposing estrogen-action, opening new avenues for therapeutic intervention in estrogen-dependent breast tumors.

Benod C, Carlsson J, Uthayaruban R, et al.
Structure-based discovery of antagonists of nuclear receptor LRH-1.
J Biol Chem. 2013; 288(27):19830-44 [PubMed] Free Access to Full Article Related Publications
Liver receptor homolog 1 (nuclear receptor LRH-1, NR5A2) is an essential regulator of gene transcription, critical for maintenance of cell pluripotency in early development and imperative for the proper functions of the liver, pancreas, and intestines during the adult life. Although physiological hormones of LRH-1 have not yet been identified, crystallographic and biochemical studies demonstrated that LRH-1 could bind regulatory ligands and suggested phosphatidylinositols as potential hormone candidates for this receptor. No synthetic antagonists of LRH-1 are known to date. Here, we identify the first small molecule antagonists of LRH-1 activity. Our search for LRH-1 modulators was empowered by screening of 5.2 million commercially available compounds via molecular docking followed by verification of the top-ranked molecules using in vitro direct binding and transcriptional assays. Experimental evaluation of the predicted ligands identified two compounds that inhibit the transcriptional activity of LRH-1 and diminish the expression of the receptor's target genes. Among the affected transcriptional targets are co-repressor SHP (small heterodimer partner) as well as cyclin E1 (CCNE1) and G0S2 genes that are known to regulate cell growth and proliferation. Treatments of human pancreatic (AsPC-1), colon (HT29), and breast adenocarcinoma cells T47D and MDA-MB-468 with the LRH-1 antagonists resulted in the receptor-mediated inhibition of cancer cell proliferation. Our data suggest that specific antagonists of LRH-1 could be used as specific molecular probes for elucidating the roles of the receptor in different types of malignancies.

Krentz AD, Murphy MW, Zhang T, et al.
Interaction between DMRT1 function and genetic background modulates signaling and pluripotency to control tumor susceptibility in the fetal germ line.
Dev Biol. 2013; 377(1):67-78 [PubMed] Free Access to Full Article Related Publications
Dmrt1 (doublesex and mab-3 related transcription factor (1) is a regulator of testis development in vertebrates that has been implicated in testicular germ cell tumors of mouse and human. In the fetal mouse testis Dmrt1 regulates germ cell pluripotency in a strain-dependent manner. Loss of Dmrt1 in 129Sv strain mice results in a >90% incidence of testicular teratomas, tumors consisting cells of multiple germ layers; by contrast, these tumors have never been observed in Dmrt1 mutants of C57BL/6J (B6) or mixed genetic backgrounds. To further investigate the interaction between Dmrt1 and genetic background we compared mRNA expression in wild type and Dmrt1 mutant fetal testes of 129Sv and B6 mice at embryonic day 15.5 (E15.5), prior to overt tumorigenesis. Loss of Dmrt1 caused misexpression of overlapping but distinct sets of mRNAs in the two strains. The mRNAs that were selectively affected included some that changed expression only in one strain or the other and some that changed in both strains but to a greater degree in one versus the other. In particular, loss of Dmrt1 in 129Sv testes caused a more severe failure to silence regulators of pluripotency than in B6 testes. A number of genes misregulated in 129Sv mutant testes also are misregulated in human testicular germ cell tumors (TGCTs), suggesting similar etiology between germ cell tumors in mouse and man. Expression profiling showed that DMRT1 also regulates pluripotency genes in the fetal ovary, although Dmrt1 mutant females do not develop teratomas. Pathway analysis indicated disruption of several signaling pathways in Dmrt1 mutant fetal testes, including Nodal, Notch, and GDNF. We used a Nanos3-cre knock-in allele to perform conditional gene targeting, testing the GDNF coreceptors Gfra1 and Ret for effects on teratoma susceptibility. Conditional deletion of Gfra1 but not Ret in fetal germ cells of animals outcrossed to 129Sv caused a modest but significant elevation in tumor incidence. Despite some variability in genetic background in these crosses, this result is consistent with previous genetic mapping of teratoma susceptibility loci to the region containing Gfra1. Using Nanos3-cre we also uncovered a strong genetic interaction between Dmrt1 and Nanos3, suggesting parallel functions for these two genes in fetal germ cells. Finally, we used chromatin immunoprecipitation (ChIP-seq) analysis to identify a number of potentially direct DMRT1 targets. This analysis suggested that DMRT1 controls pluripotency via transcriptional repression of Esrrb, Nr5a2/Lrh1, and Sox2. Given the strong evidence for involvement of DMRT1 in human TGCT, the downstream genes and pathways identified in this study provide potentially useful candidates for roles in the human disease.

Muscat GE, Eriksson NA, Byth K, et al.
Research resource: nuclear receptors as transcriptome: discriminant and prognostic value in breast cancer.
Mol Endocrinol. 2013; 27(2):350-65 [PubMed] Related Publications
To identify biologically relevant groupings or clusters of nuclear receptors (NR) that are associated with breast neoplasia, with potentially diagnostic, discriminant or prognostic value, we quantitated mRNA expression levels of all 48 members of the human NR superfamily by TaqMan low-density array analysis in 116 curated breast tissue samples, including pre- and postmenopausal normal breast and both ERα(+) and ERα(-) tumor tissue. In addition, we have determined NR levels in independent cohorts of tamoxifen-treated ERα(+) and ERα(-) tissue samples. There were differences in relative NR mRNA expression between neoplastic and normal breast, and between ER(+) and ER(-) tumors. First, there is overexpression of the NUR77 subgroup and EAR2 in neoplastic breast. Second, we identify a signature of five NR (ERα, EAR2, NUR77, TRα, and RARγ) that classifies breast samples with more than 97% cross-validated accuracy into normal or cancer classes. Third, we find a novel negative association between five NR (TRβ, NUR77, RORγ, COUP-TFII, and LRH1) and histological grade. Finally, four NR (COUP-TFII, TRβ, PPARγ, and MR) are significant predictors of metastasis-free survival in tamoxifen-treated breast cancers, independent of ER expression. The present study highlights the discriminant and prognostic value of NR in breast cancer; identifies novel, clinically relevant, NR signatures; and highlights NR signaling pathways with potential roles in breast cancer pathophysiology and as new therapeutic targets.

Alagaratnam S, Harrison N, Bakken AC, et al.
Transforming pluripotency: an exon-level study of malignancy-specific transcripts in human embryonal carcinoma and embryonic stem cells.
Stem Cells Dev. 2013; 22(7):1136-46 [PubMed] Related Publications
To circumvent difficulties of isolating pure populations of cancer stem cells (CSCs) for the purpose of identifying malignancy-specific gene expression, we have compared exon-resolution transcriptomic profiles of 5 embryonal carcinoma (EC) cell lines, a histological subtype of germ cell tumor (GCT), to their nonmalignant caricature, specifically 6 human embryonic stem (ES) cell lines. Both cell types are readily accessible, and were purified for undifferentiated cells only. We identified a set of 28 differentially expressed genes, many of which had cancer and stemness roles. Overexpression of the recently discovered pluripotency gene NR5A2 in malignant EC cells revealed an intriguing indication of how WNT-mediated dysregulation of pluripotency is involved with malignancy. Expression of these 28 genes was further explored within 2 publically available data sets of primary EC tumors and normal testis. At the exon-level, alternative splicing events were detected in ZNF195, DNMT3B, and PMF1, and alternative promoters were detected for ASH2L and ETV5. These events were validated by reverse transcriptase-polymerase chain reaction-based methods in EC and ES lines, where the alternative splicing event in the de novo DNA methyltransferase DNMT3B may have functional consequences. In conclusion, we have identified malignancy-specific gene expression differences within a rigorous pluripotent stem cell context. These findings are of particular interest for both GCT and ES cell biology, and, in general, to the concept of CSCs.

Bianco C, Castro NP, Baraty C, et al.
Regulation of human Cripto-1 expression by nuclear receptors and DNA promoter methylation in human embryonal and breast cancer cells.
J Cell Physiol. 2013; 228(6):1174-88 [PubMed] Free Access to Full Article Related Publications
Human Cripto-1 (CR-1) plays an important role in regulating embryonic development while also regulating various stages of tumor progression. However, mechanisms that regulate CR-1 expression during embryogenesis and tumorigenesis are still not well defined. In the present study, we investigated the effects of two nuclear receptors, liver receptor homolog (LRH)-1 and germ cell nuclear factor receptor (GCNF) and epigenetic modifications on CR-1 gene expression in NTERA-2 human embryonal carcinoma cells and in breast cancer cells. CR-1 expression in NTERA-2 cells was positively regulated by LRH-1 through direct binding to a DR0 element within the CR-1 promoter, while GCNF strongly suppressed CR-1 expression in these cells. In addition, the CR-1 promoter was unmethylated in NTERA-2 cells, while T47D, ZR75-1, and MCF7 breast cancer cells showed high levels of CR-1 promoter methylation and low CR-1 mRNA and protein expression. Treatment of breast cancer cells with a demethylating agent and histone deacetylase inhibitors reduced methylation of the CR-1 promoter and reactivated CR-1 mRNA and protein expression in these cells, promoting migration and invasion of breast cancer cells. Analysis of a breast cancer tissue array revealed that CR-1 was highly expressed in the majority of human breast tumors, suggesting that CR-1 expression in breast cancer cell lines might not be representative of in vivo expression. Collectively, these findings offer some insight into the transcriptional regulation of CR-1 gene expression and its critical role in the pathogenesis of human cancer.

Sung B, Do HJ, Park SW, et al.
Regulation of OCT4 gene expression by liver receptor homolog-1 in human embryonic carcinoma cells.
Biochem Biophys Res Commun. 2012; 427(2):315-20 [PubMed] Related Publications
We demonstrate the regulation of OCT4 gene expression mediated by liver receptor homolog-1 (LRH-1) in human embryonic carcinoma cells. LRH-1 and OCT4 are co-expressed in undifferentiated NCCIT cells and decreased during retinoic acid-induced differentiation. Dose-dependent overexpression of LRH-1 transactivated the OCT4 promoter activity and its dominant negative form with a deletion of activation function-2 motif reduced the activity even in the presence of LRH-1. The OCT4 promoter contains potent three LRH-1 binding sites; one within conserved region (CR) 1 and two within CR2. Mutagenesis of each binding site affected the decrease in OCT4 promoter activity and the 2nd binding site mutant most significantly reduced the transcriptional activity, compared to that of 1st and 3rd binding site mutants, respectively. Simultaneous disruption of 2nd and 3rd binding sites led to significant down-regulation of the activity even in the presence of 1st binding site-containing CR1. Moreover, mutation of each binding element within native or exogenous minimal promoter-driven CR1 or CR2 also decreased the promoter activity to some different extent, suggesting that three binding elements may be implicated in the induction of the full-activity of OCT4 promoter. In vivo binding assay revealed the 2nd and 3rd binding motifs within CR2 were more enriched than the 1st one within CR1. Taken together, our study indicates that LRH-1 acts as a transcriptional activator in the regulation of OCT4 gene expression through the cooperative interaction with three binding sites directly or/and indirectly.

Aguilar B, Choi I, Choi D, et al.
Lymphatic reprogramming by Kaposi sarcoma herpes virus promotes the oncogenic activity of the virus-encoded G-protein-coupled receptor.
Cancer Res. 2012; 72(22):5833-42 [PubMed] Free Access to Full Article Related Publications
Kaposi sarcoma, the most common cancer in HIV-positive individuals, is caused by endothelial transformation mediated by the Kaposi sarcoma herpes virus (KSHV)-encoded G-protein-coupled receptor (vGPCR). Infection of blood vascular endothelial cells (BEC) by KSHV reactivates an otherwise silenced embryonic program of lymphatic differentiation. Thus, Kaposi sarcoma tumors express numerous lymphatic endothelial cell (LEC) signature genes. A key unanswered question is how lymphatic reprogramming by the virus promotes tumorigenesis leading to Kaposi sarcoma formation. In this study, we present evidence that this process creates an environment needed to license the oncogenic activity of vGPCR. We found that the G-protein regulator RGS4 is an inhibitor of vGPCR that is expressed in BECs, but not in LECs. RGS4 was downregulated by the master regulator of LEC differentiation PROX1, which is upregulated by KSHV and directs KSHV-induced lymphatic reprogramming. Moreover, we found that KSHV upregulates the nuclear receptor LRH1, which physically interacts with PROX1 and synergizes with it to mediate repression of RGS4 expression. Mechanistic investigations revealed that RGS4 reduced vGPCR-enhanced cell proliferation, migration, VEGF expression, and Akt activation and suppressed tumor formation induced by vGPCR. Our findings resolve long-standing questions about the pathologic impact of KSHV-induced reprogramming of host cell identity, and they offer biologic and mechanistic insights supporting the hypothesis that a lymphatic microenvironment is more favorable for Kaposi sarcoma tumorigenesis.

Li D, Duell EJ, Yu K, et al.
Pathway analysis of genome-wide association study data highlights pancreatic development genes as susceptibility factors for pancreatic cancer.
Carcinogenesis. 2012; 33(7):1384-90 [PubMed] Free Access to Full Article Related Publications
Four loci have been associated with pancreatic cancer through genome-wide association studies (GWAS). Pathway-based analysis of GWAS data is a complementary approach to identify groups of genes or biological pathways enriched with disease-associated single-nucleotide polymorphisms (SNPs) whose individual effect sizes may be too small to be detected by standard single-locus methods. We used the adaptive rank truncated product method in a pathway-based analysis of GWAS data from 3851 pancreatic cancer cases and 3934 control participants pooled from 12 cohort studies and 8 case-control studies (PanScan). We compiled 23 biological pathways hypothesized to be relevant to pancreatic cancer and observed a nominal association between pancreatic cancer and five pathways (P < 0.05), i.e. pancreatic development, Helicobacter pylori lacto/neolacto, hedgehog, Th1/Th2 immune response and apoptosis (P = 2.0 × 10(-6), 1.6 × 10(-5), 0.0019, 0.019 and 0.023, respectively). After excluding previously identified genes from the original GWAS in three pathways (NR5A2, ABO and SHH), the pancreatic development pathway remained significant (P = 8.3 × 10(-5)), whereas the others did not. The most significant genes (P < 0.01) in the five pathways were NR5A2, HNF1A, HNF4G and PDX1 for pancreatic development; ABO for H.pylori lacto/neolacto; SHH for hedgehog; TGFBR2 and CCL18 for Th1/Th2 immune response and MAPK8 and BCL2L11 for apoptosis. Our results provide a link between inherited variation in genes important for pancreatic development and cancer and show that pathway-based approaches to analysis of GWAS data can yield important insights into the collective role of genetic risk variants in cancer.

Chand AL, Wijayakumara DD, Knower KC, et al.
The orphan nuclear receptor LRH-1 and ERα activate GREB1 expression to induce breast cancer cell proliferation.
PLoS One. 2012; 7(2):e31593 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Liver Receptor Homolog 1 (LRH-1, NR5A2) is an orphan nuclear receptor that is over-expressed in cancers in tissues such as the breast, colon and pancreas. LRH-1 plays important roles in embryonic development, steroidogenesis and cholesterol homeostasis. In tumor cells, LRH-1 induces proliferation and cell cycle progression. High LRH-1 expression is demonstrated in breast cancers, positively correlating with ERα status and aromatase activity. LRH-1 dependent cellular mechanisms in breast cancer epithelial cells are poorly defined. Hence in the present study we investigated the actions of LRH-1 in estrogen receptor α (ERα) positive breast cancer cells.
RESULTS: The study aimed to investigate LRH-1 dependent mechanisms that promote breast cancer proliferation. We identified that LRH-1 regulated the expression of Growth Regulation by Estrogen in Breast Cancer 1 (GREB1) in MCF-7 and MDA-MB-231 cells. Over-expression of LRH-1 increased GREB1 mRNA levels while knockdown of LRH-1 reduced its expression. GREB1 is a well characterised ERα target gene, with three estrogen response elements (ERE) located on its promoter. Chromatin immunoprecipitation studies provided evidence of the co-localisation of LRH-1 and ERα at all three EREs. With electrophoretic mobility shift assays, we demonstrated direct binding of LRH-1 to EREs located on GREB1 and Trefoil Factor 1 (TFF1, pS2) promoters. LRH-1 and ERα co-operatively activated transcription of ERE luciferase reporter constructs suggesting an overlap in regulation of target genes in breast cancer cells. Over-expression of LRH-1 resulted in an increase in cell proliferation. This effect was more pronounced with estradiol treatment. In the presence of ICI 182,780, an ERα antagonist, LRH-1 still induced proliferation.
CONCLUSIONS: We conclude that in ER-positive breast cancer cells, LRH-1 promotes cell proliferation by enhancing ERα mediated transcription of target genes such as GREB-1. Collectively these findings indicate the importance of LRH-1 in the progression of hormone-dependent breast cancer and implicate LRH-1 as a potential avenue for drug development.

Straume AH, Løvås K, Miletic H, et al.
Elevated levels of the steroidogenic factor 1 are associated with over-expression of CYP19 in an oestrogen-producing testicular Leydig cell tumour.
Eur J Endocrinol. 2012; 166(5):941-9 [PubMed] Free Access to Full Article Related Publications
BACKGROUND AND OBJECTIVES: Testicular Leydig cell tumours (LCTs) are rare, steroid-secreting tumours. Elevated levels of aromatase (CYP19 or CYP19A1) mRNA have been previously described in LCTs; however, little is known about the mechanism(s) causing CYP19 over-expression. We report an LCT in a 29-year-old male with elevated plasma oestradiol caused by enhanced CYP19 transcription.
DESIGN AND METHODS: First, we measured the intra-tumour expression of CYP19 and determined the use of CYP19 promoters by qPCR. Secondly, we explored CYP19 and promoter II (PII) for gene amplifications and activating mutations in PII by sequencing. Thirdly, we analysed intra-tumour expression of steroidogenic factor 1 (SF-1 (NR5A1)), liver receptor homologue-1 (LRH-1 (NR5A2)) and cyclooxygenase-2 (COX2 (PTGS2)). Finally, we analysed SF-1 for promoter mutations and gene amplifications.
RESULTS: Similar to what has been recorded in normal Leydig cells, we first found the bulk of tumour CYP19 transcripts to be PII derived, excluding promoter shift as a cause of enhanced transcription. Secondly, we excluded CYP19 and PII gene amplifications, and activating mutations in PII, as causes of elevated CYP19 mRNA. We found SF-1 mRNA to be up-regulated in the tumour, while LRH-1 and COX2 were down-regulated. The finding of elevated SF-1 levels in the tumour was confirmed by immunohistochemistry. The elevated level of SF-1 was not due to promoter mutations or amplifications of the SF-1 gene.
CONCLUSIONS: Our results strongly suggest that the elevated levels of SF-1 have induced PII-regulated CYP19 transcription in this tumour. These findings are of relevance to the understanding of CYP19 up-regulation in general, which may occur in several tissues, including breast cancer.

Rizzato C, Campa D, Giese N, et al.
Pancreatic cancer susceptibility loci and their role in survival.
PLoS One. 2011; 6(11):e27921 [PubMed] Free Access to Full Article Related Publications
Pancreatic cancer has one of the worst mortality rates of all cancers. Little is known about its etiology, particularly regarding inherited risk. The PanScan project, a genome-wide association study, identified several common polymorphisms affecting pancreatic cancer susceptibility. Single nucleotide polymorphisms (SNPs) in ABO, sonic hedgehog (SHH), telomerase reverse transcriptase (TERT), nuclear receptor subfamily 5, group A, member 2 (NR5A2) were found to be associated with pancreatic cancer risk. Moreover the scan identified loci on chromosomes 13q22.1 and 15q14, to which no known genes or other functional elements are mapped. We sought to replicate these observations in two additional, independent populations (from Germany and the UK), and also evaluate the possible impact of these SNPs on patient survival. We genotyped 15 SNPs in 690 cases of pancreatic ductal adenocarcinoma (PDAC) and in 1277 healthy controls. We replicated several associations between SNPs and PDAC risk. Furthermore we found that SNP rs8028529 was weakly associated with a better overall survival (OS) in both populations. We have also found that NR5A2 rs12029406_T allele was associated with a shorter survival in the German population. In conclusion, we found that rs8028529 could be, if these results are replicated, a promising marker for both risk and prognosis for this lethal disease.

Benod C, Vinogradova MV, Jouravel N, et al.
Nuclear receptor liver receptor homologue 1 (LRH-1) regulates pancreatic cancer cell growth and proliferation.
Proc Natl Acad Sci U S A. 2011; 108(41):16927-31 [PubMed] Free Access to Full Article Related Publications
An essential regulator of gene transcription, nuclear receptor liver receptor homologue 1 (LRH-1) controls cell differentiation in the developing pancreas and maintains cholesterol homeostasis in adults. Recent genome-wide association studies linked mutations in the LRH-1 gene and its up-stream regulatory regions to development of pancreatic cancer. In this work, we show that LRH-1 transcription is activated up to 30-fold in human pancreatic cancer cells compared to normal pancreatic ductal epithelium. This activation correlates with markedly increased LRH-1 protein expression in human pancreatic ductal adenocarcinomas in vivo. Selective blocking of LRH-1 by receptor specific siRNA significantly inhibits pancreatic cancer cell proliferation in vitro. The inhibition is tracked in part to the attenuation of the receptor's transcriptional targets controlling cell growth, proliferation, and differentiation. Previously, LRH-1 was shown to contribute to formation of intestinal tumors. This study demonstrates the critical involvement of LRH-1 in development and progression of pancreatic cancer, suggesting the LRH-1 receptor as a plausible therapeutic target for treatment of pancreatic ductal adenocarcinomas.

Shigemura K, Huang WC, Li X, et al.
Active sonic hedgehog signaling between androgen independent human prostate cancer cells and normal/benign but not cancer-associated prostate stromal cells.
Prostate. 2011; 71(16):1711-22 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Sonic hedgehog (Shh) signaling plays a pivotal role in stromal-epithelial interaction during normal development but its role in tumor-stromal interaction during carcinogenic progression is less well defined. Since hormone refractory prostate cancer with bone metastasis is difficult to treat, it is crucial to investigate how androgen independent (AI) human prostate cancer cells communicate with their associated stroma.
METHODS: Shh and its target transcription factor, Gli1 mRNA, were assessed by RT-PCR and/or quantitative RT-PCR in co-cultured cell recombinants comprised of AI C4-2 either with NPF (prostate fibroblasts from normal/benign prostate gland) or CPF (cancer-associated stromal fibroblasts) under Shh/cyclopamine (a hedgehog signaling inhibitor) treatment. Human bone marrow stromal (HS27A) cells were used as controls. In vivo investigation was performed by checking serum PSA and immunohistochemical staining for the apoptosis-associated M30 gene in mice bearing chimeric C4-2/NPF tumors.
RESULTS: We found that (1) Shh has minimal growth-stimulating effects on prostate cancer cells, but it stimulated the growth of NPF but not CPF; (2) active Shh signaling was found between AI C4-2 cells and NPF but not CPF; and (3) osteonectin (ON) is a Gli1 target gene in NPF and not in CPF, and ON up-regulation in NPF can be blocked by cyclopamine
CONCLUSIONS: Based on co-culture and chimeric tumor models, active Shh-mediated signaling was demonstrated between AI prostate cancer and NPF in a paracrine- and tumor progression-dependent manner. Our study suggests that drugs like cyclopamine that interfere with Shh signaling could be beneficial in preventing AI progression in prostate cancer cells.

Chand AL, Herridge KA, Howard TL, et al.
Tissue-specific regulation of aromatase promoter II by the orphan nuclear receptor LRH-1 in breast adipose stromal fibroblasts.
Steroids. 2011; 76(8):741-4 [PubMed] Related Publications
In postmenopausal breast cancers, the increase in aromatase expression observed in tumour associated adipose stromal cells is mediated via the upregulation of promoter II (PII) transcription. Factors such as PGE₂ which are secreted from breast carcinomas induce PII expression. The orphan nuclear receptor LRH-1/NR5A2 is one of the critical downstream transcriptional mediators of this effect. The aim of the current study was to determine whether LRH-1 could bind directly to PII and whether the suppression of LRH-1 expression could inhibit aromatase expression in human adipose stromal fibroblasts. Chromatin immunoprecipitation demonstrated endogenous LRH-1 occupancy on PII under basal conditions and with treatment with forskolin and phorbol 12-myristate 13-acetate (PMA). To assess the impact of LRH-1 knockdown on FSK/PMA mediated PII expression, cells were transfected with shRNA targeted against LRH-1 (shLRH-1) and treated with forskolin and PMA. A decrease in LRH-1, PII and total aromatase mRNA transcripts was observed in shLRH-1 transfected cells compared to controls under basal and treatment conditions. The results of this study support the hypothesis that suppression of LRH-1 may potentially be beneficial in the tissue specific regulation of aromatase expression in post menopausal breast cancer.

Tang H, Dong X, Hassan M, et al.
Body mass index and obesity- and diabetes-associated genotypes and risk for pancreatic cancer.
Cancer Epidemiol Biomarkers Prev. 2011; 20(5):779-92 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The genetic factors predisposing individuals with obesity or diabetes to pancreatic cancer have not been identified.
AIMS: To investigate the hypothesis that obesity- and diabetes-related genes modify the risk of pancreatic cancer.
METHODS: We genotyped 15 single nucleotide polymorphisms of fat mass and obesity-associated (FTO), peroxisome proliferators-activated receptor gamma (PPARγ), nuclear receptor family 5 member 2 (NR5A2), AMPK, and ADIPOQ genes in 1,070 patients with pancreatic cancer and 1,175 cancer-free controls. Information on risk factors was collected by personal interview. Adjusted ORs (AOR) and 95% CIs were calculated using unconditional logistic regression.
RESULTS: The PPARγ P12A GG genotype was inversely associated with risk of pancreatic cancer (AOR, 0.21; 95% CI, 0.07-0.62). Three NR5A2 variants that were previously identified in a genome-wide association study were significantly associated with reduced risk of pancreatic cancer, AORs ranging from 0.57 to 0.79. Two FTO gene variants and one ADIPOQ variant were differentially associated with pancreatic cancer according to levels of body mass index (BMI; P(interaction) = 0.0001, 0.0015, and 0.03). For example, the AOR (95% CI) for FTO IVS1-2777AC/AA genotype was 0.72 (0.55-0.96) and 1.54 (1.14-2.09) in participants with a BMI of less than 25 or 25 kg/m(2) or more, respectively. We observed no significant association between AMPK genotype and pancreatic cancer and no genotype interactions with diabetes or smoking.
CONCLUSION: Our findings suggest the PPARγ P12A GG genotype and NR5A2 variants may reduce the risk for pancreatic cancer. A positive association of FTO and ADIPOQ gene variants with pancreatic cancer may be limited to persons who are overweight.
IMPACT: The discovery of genetic factors modifying the risk of pancreatic cancer may help to identify high-risk individuals for prevention efforts.

Sidler D, Renzulli P, Schnoz C, et al.
Colon cancer cells produce immunoregulatory glucocorticoids.
Oncogene. 2011; 30(21):2411-9 [PubMed] Related Publications
Glucocorticoids (GC) have important anti-inflammatory and pro-apoptotic activities. Initially thought to be exclusively produced by the adrenal glands, there is now increasing evidence for extra-adrenal sources of GCs. We have previously shown that the intestinal epithelium produces immunoregulatory GCs and that intestinal steroidogenesis is regulated by the nuclear receptor liver receptor homolog-1 (LRH-1). As LRH-1 has been implicated in the development of colon cancer, we here investigated whether LRH-1 regulates GC synthesis in colorectal tumors and whether tumor-produced GCs suppress T-cell activation. Colorectal cancer cell lines and primary tumors were found to express steroidogenic enzymes and regulatory factors required for the de novo synthesis of cortisol. Both cell lines and primary tumors constitutively produced readily detectable levels of cortisol, as measured by radioimmunoassay, thin-layer chromatography and bioassay. Whereas overexpression of LRH-1 significantly increased the expression of steroidogenic enzymes and the synthesis of cortisol, downregulation or inhibition of LRH-1 effectively suppressed these processes, indicating an important role of LRH-1 in colorectal tumor GC synthesis. An immunoregulatory role of tumor-derived GCs could be further confirmed by demonstrating a suppression of T-cell activation. This study describes for the first time cortisol synthesis in a non-endocrine tumor in humans, and suggests that the synthesis of bioactive GCs in colon cancer cells may account as a novel mechanism of tumor immune escape.

Fleming NI, Knower KC, Lazarus KA, et al.
Aromatase is a direct target of FOXL2: C134W in granulosa cell tumors via a single highly conserved binding site in the ovarian specific promoter.
PLoS One. 2010; 5(12):e14389 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Granulosa cell tumors (GCT) of the ovary often express aromatase and synthesize estrogen, which in turn may influence their progression. Recently a specific point mutation (C134W) in the FOXL2 protein was identified in >94% of adult-type GCT and it is likely to contribute to their development. A number of genes are known to be regulated by FOXL2, including aromatase/CYP19A1, but it is unclear which are direct targets and whether the C134W mutation alters their regulation. Recently, it has been reported that FOXL2 forms a complex with steroidogenic factor 1 (SF-1) which is a known regulator of aromatase in granulosa cells.
METHODOLOGY/PRINCIPAL FINDINGS: In this work, the human GCT-derived cell lines KGN and COV434 were heterozygous and wildtype for the FOXL2:C134W mutation, respectively. KGN had abundant FOXL2 mRNA expression but it was not expressed in COV434. Expression of exogenous FOXL2:C134W in COV434 cells induced higher expression of a luciferase reporter for the ovarian specific aromatase promoter, promoter II (PII) (-516bp) than expression of wildtype FOXL2, but did not alter induction of a similar reporter for the steroidogenic acute regulatory protein (StAR) promoter (-1300bp). Co-immunoprecipitation confirmed that FOXL2 bound SF-1 and that it also bound its homologue, liver receptor homologue 1 (LRH-1), however, the C134W mutation did not alter these interactions or induce a selective binding of the proteins. A highly conserved putative binding site for FOXL2 was identified in PII. FOXL2 was demonstrated to bind the site by electrophoretic mobility shift assays (EMSA) and site-directed mutagenesis of this element blocked its differential induction by wildtype FOXL2 and FOXL2:C134W.
CONCLUSIONS/SIGNIFICANCE: These findings suggest that aromatase is a direct target of FOXL2:C134W in adult-type GCT via a single distinctive and highly conserved binding site in PII and therefore provide insight into the pathogenic mechanism of this mutation.

Li D, Abbruzzese JL
New strategies in pancreatic cancer: emerging epidemiologic and therapeutic concepts.
Clin Cancer Res. 2010; 16(17):4313-8 [PubMed] Free Access to Full Article Related Publications
Pancreatic cancer (PC) is a highly lethal disease with complex etiology involving both environmental and genetic factors. Although cigarette smoking is known to explain 25% of cases, data from recent studies suggest that obesity and long-term type II diabetes are two major modifiable risk factors for PC. Furthermore, obesity and diabetes seem to affect the clinical outcome of patients with PC. Understanding the mechanistic effects of obesity and diabetes on the pancreas may identify new strategies for prevention or therapy. Experimental and epidemiologic evidence suggests that the antidiabetic drug metformin has protective antitumor activity in PC. In addition to insulin resistance and inflammation as mechanisms of carcinogenesis, obesity and diabetes are linked to impairments in endothelial function and coagulation status, which increase the risks of thrombosis and angiogenesis and, in turn, the risk of PC development and progression. The associations of the ABO blood group gene and NR5A2 gene variants with PC discovered by recent genome-wide association studies may link insulin resistance, inflammation, and thrombosis to pancreatic carcinogenesis. These exciting findings open new avenues for understanding the etiology of PC and provide opportunities for developing novel strategies for prevention and treatment of this disease.

Thiruchelvam PT, Lai CF, Hua H, et al.
The liver receptor homolog-1 regulates estrogen receptor expression in breast cancer cells.
Breast Cancer Res Treat. 2011; 127(2):385-96 [PubMed] Related Publications
Estrogen receptor-α (ER) is expressed in the great majority of breast cancers, and the inhibition of ER action is a key part of breast cancer treatment. The inhibition of ER action is achieved using anti-estrogens, primarily tamoxifen, and with aromatase inhibitors that inhibit estrogen biosynthesis, thereby preventing ER activation. However, resistance to these therapies is common. With the aim of identifying new molecular targets for breast cancer therapy, we have identified the liver receptor homolog-1 (LRH-1) as an estrogen-regulated gene. RNA interference and over-expression studies were used to investigate the role of the LRH-1 in regulating breast cancer growth and to identify the targets of an LRH-1 action. Promoter recruitment was determined using reporter gene and chromatin immunoprecipitation (ChIP) assays. We show that LRH-1 regulates breast cancer cell growth by regulating the ER expression. Reporter gene and in vitro DNA-binding assays identified an LRH-1-binding site in the ER gene promoter, and ChIP assays have demonstrated in vivo binding at this site. We also provide evidence for new LRH-1 variants in breast cancer cells arising from the use of alternative promoters. Previous studies have shown that LRH-1 functions in estrogen biosynthesis by regulating aromatase expression. Our findings extend this by highlighting LRH-1 as a key regulator of the estrogen response in breast cancer cells through the regulation of ER expression. Hence, inhibition of LRH-1 could provide a powerful new approach for the treatment of endocrine-resistant breast cancer.

Adams H, Fritzsche FR, Dirnhofer S, et al.
Class I histone deacetylases 1, 2 and 3 are highly expressed in classical Hodgkin's lymphoma.
Expert Opin Ther Targets. 2010; 14(6):577-84 [PubMed] Related Publications
OBJECTIVE: HDAC inhibitors (HDI) are anti-neoplastic drugs with preliminary successful clinical applications in Hodgkin's lymphoma (HL). Systematic investigations of HDAC expression in HL, based on histology and immunohistochemistry are yet rare.
RESEARCH DESIGN/METHODS: We investigated the expression of HDAC1, 2 and 3 in 283 HL on tissue microarrays.
MAIN OUTCOME MEASURES: Expression of HDAC isoforms was scored in Hodgkin and Reed-Sternberg cells (HRSC) and background infiltrate and compared with freedom of treatment failure (FTF) in 118 cases, for which all data was available.
RESULTS: All analyzable HL expressed the HDAC isoforms 2 (n = 194) and 3 (n = 207) in over 50%, mostly 100%, of HRSC and almost all background lymphocytes. HDAC1 was expressed in 169 of 179 analyzable HL in a mean of 82% and in 172 out of 179 analyzable cases in a mean of 83% of infiltrating lymphocytes. HDAC1 of below 75% in HRSC correlated with worse FTF with 16 out of 32 events, compared with 16 out of 82 in cases with over 75% HDAC1-expressing HRSC.
CONCLUSION: HDAC isoforms 1, 2 and 3 are highly expressed in HL. In addition, decreased HDAC1 expression is accompanied by worse outcome in HL.

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