Progesterone receptor modulates ERα action in breast cancer

Gaussian Mixture Models for Probabilistic Classification of Breast Cancer

In the era of omics-driven research, it remains a common dilemma to stratify individual patients based on the molecular characteristics of their tumors. To improve molecular stratification of patients with breast cancer, we developed the Gaussian mixture model (GMM)-based classifier. This probabilistic classifier was built on mRNA expression data from more than 300 clinical samples of breast cancer and healthy tissue and was validated on datasets of ESR1, PGR, and ERBB2, which encode standard clinical markers and therapeutic targets. To demonstrate how a GMM approach could be exploited for multiclass classification using data from a candidate marker, we analyzed the insulin-like growth factor I receptor (IGF1R), a promising target, but a marker of uncertain importance in breast cancer. The GMM defined subclasses with downregulated (40%), unchanged (39%), upregulated (19%), and overexpressed (2%) IGF1R levels; inter- and intrapatient analyses of IGF1R transcript and protein levels supported these predictions. Overexpressed IGF1R was observed in a small percentage of tumors. Samples with unchanged and upregulated IGF1R were differentiated tumors, and downregulation of IGF1R correlated with poorly differentiated, high-risk hormone receptor-negative and HER2-positive tumors. A similar correlation was found in the independent cohort of carcinoma in situ, suggesting that loss or low expression of IGF1R is a marker of aggressiveness in subsets of preinvasive and invasive breast cancer. These results demonstrate the importance of probabilistic modeling that delves deeper into molecular data and aims to improve diagnostic classification, prognostic assessment, and treatment selection. SIGNIFICANCE: A GMM classifier demonstrates potential use for clinical validation of markers and determination of target populations, particularly when availability of specimens for marker development is low.

Progesterone Receptor Attenuates STAT1-Mediated IFN Signaling in Breast Cancer

Why some tumors remain indolent and others progress to clinical relevance remains a major unanswered question in cancer biology. IFN signaling in nascent tumors, mediated by STAT1, is a critical step through which the surveilling immune system can recognize and destroy developing tumors. In this study, we have identified an interaction between the progesterone receptor (PR) and STAT1 in breast cancer cells. This interaction inhibited efficient IFN-induced STAT1 phosphorylation, as we observed a decrease in phospho-STAT1 in response to IFN treatment in PR-positive breast cancer cell lines. This phenotype was further potentiated in the presence of PR ligand. In human breast cancer samples, PR-positive tumors exhibited lower levels of phospho-STAT1 as compared with their PR-negative counterparts, indicating that this phenotype translates to human tumors. Breast cancer cells lacking PR exhibited higher levels of IFN-stimulated gene (ISG) RNA, the transcriptional end point of IFN activation, indicating that unliganded PR alone could decrease transcription of ISGs. Moreover, the absence of PR led to increased recruitment of STAT1, STAT2, and IRF9 (key transcription factors necessary for ISG transcription) to ISG promoters. These data indicate that PR, both in the presence and absence of ligand, attenuates IFN-induced STAT1 signaling, culminating in significantly abrogated activation of genes transcribed in response to IFNs. PR-positive tumors may use downregulation of STAT1-mediated IFN signaling to escape immune surveillance, leading to the development of clinically relevant tumors. Selective immune evasion of PR-positive tumors may be one explanation as to why over 65% of breast cancers are PR positive at the time of diagnosis.

Ligand-activated progesterone receptor B activates transcription factor EB to promote autophagy in human breast cancer cells

Autophagy is an evolutionary conserved, self-eating process that targets cellular constituents for lysosomal degradation. Transcription factor EB (TFEB) is a master regulator of autophagy by inducing the expression of genes involved in autophagic and lysosomal degradation. In breast cancer, ligand-activated progesterone receptor has been reported to influence cancer development by manipulating the autophagy pathway. However, understanding of the mechanism that underlies this autophagic response remains limited. Herein, we report that prolonged treatment with progestin R5020 upregulates autophagy in MCF-7 human breast cancer cells via a novel interplay between progesterone receptor B (PRB) and TFEB. R5020 upregulates TFEB gene expression and protein levels in a PRB-dependent manner. Additionally, R5020 enhances the co-recruitment of PRB and TFEB to each other to facilitate TFEB nuclear localization. Once in the nucleus, TFEB induces the expression of autophagy and lysosomal genes to potentiate autophagy. Together, our findings highlight a novel functional connection between ligand-activated PRB and TFEB to modulate autophagy in MCF-7 breast cancer cells. As breast cancer development is controlled by autophagy, the progestin-PRB-TFEB transduction pathway warrants future attention as a potential therapeutic target in cancer therapy.

Grainyhead-like Protein 2: The Emerging Role in Hormone-Dependent Cancers and Epigenetics

In mammals, the grainyhead-like transcription factor (GRHL) family is composed of three nuclear proteins that are responsible for driving epithelial cell fate: GRHL1, GRHL2, and GRHL3. GRHL2 is important in maintaining proper tubulogenesis during development and in suppressing the epithelial-to-mesenchymal transition. Within the last decade, evidence indicates both tumor-suppressive and oncogenic roles for GRHL2 in various types of cancers. Recent studies suggest that GRHL2 may be especially important in hormone-dependent cancers, as correlative relationships exist between GRHL2 and various steroid receptors, such as the androgen and estrogen receptors. Acting as a pioneer factor and coactivator, GRHL2 may directly affect steroid receptor transcriptional activity. This review will highlight recent discoveries of GRHL2 activity in cancer and in maintaining the epithelial state, while also exploring recent literature on the role of GRHL2 in hormone-dependent cancers and epigenetics.

LLGL2 rescues nutrient stress by promoting leucine uptake in ER+ breast cancer

Drosophila Lgl and its mammalian homologues, LLGL1 and LLGL2, are scaffolding proteins that regulate the establishment of apical-basal polarity in epithelial cells^1,2. Whereas Lgl functions as a tumour suppressor in Drosophila¹, the roles of mammalian LLGL1 and LLGL2 in cancer are unclear. The majority (about 75%) of breast cancers express oestrogen receptors (ERs)³, and patients with these tumours receive endocrine treatment⁴. However, the development of resistance to endocrine therapy and metastatic progression are leading causes of death for patients with ER⁺ disease⁴. Here we report that, unlike LLGL1, LLGL2 is overexpressed in ER⁺ breast cancer and promotes cell proliferation under nutrient stress. LLGL2 regulates cell surface levels of a leucine transporter, SLC7A5, by forming a trimeric complex with SLC7A5 and a regulator of membrane fusion, YKT6, to promote leucine uptake and cell proliferation. The oestrogen receptor targets LLGL2 expression. Resistance to endocrine treatment in breast cancer cells was associated with SLC7A5- and LLGL2-dependent adaption to nutrient stress. SLC7A5 was necessary and sufficient to confer resistance to tamoxifen treatment, identifying SLC7A5 as a potential therapeutic target for overcoming resistance to endocrine treatments in breast cancer. Thus, LLGL2 functions as a promoter of tumour growth and not as a tumour suppressor in ER⁺ breast cancer. Beyond breast cancer, adaptation to nutrient stress is critically important⁵, and our findings identify an unexpected role for LLGL2 in this process.

Identification of ChIP-seq and RIME grade antibodies for Estrogen Receptor alpha

Estrogen Receptor alpha (ERα) plays a major role in most breast cancers, and it is the target of endocrine therapies used in the clinic as standard of care for women with breast cancer expressing this receptor. The two methods ChIP-seq (chromatin immunoprecipitation coupled with deep sequencing) and RIME (Rapid Immunoprecipitation of Endogenous Proteins) have greatly improved our understanding of ERα function during breast cancer progression and in response to anti-estrogens. A critical component of both ChIP-seq and RIME protocols is the antibody that is used against the bait protein. To date, most of the ChIP-seq and RIME experiments for the study of ERα have been performed using the sc-543 antibody from Santa Cruz Biotechnology. However, this antibody has been discontinued, thereby severely impacting the study of ERα in normal physiology as well as diseases such as breast cancer and ovarian cancer. Here, we compare the sc-543 antibody with other commercially available antibodies, and we show that 06-935 (EMD Millipore) and ab3575 (Abcam) antibodies can successfully replace the sc-543 antibody for ChIP-seq and RIME experiments.

Decoding the Inversion Symmetry Underlying Transcription Factor DNA-Binding Specificity and Functionality in the Genome

Understanding why a transcription factor (TF) binds to a specific DNA element in the genome and whether that binding event affects transcriptional output remains a great challenge. In this study, we demonstrate that TF binding in the genome follows inversion symmetry (IS). In addition, the specific DNA elements where TFs bind in the genome are determined by internal IS within the DNA element. These DNA-binding rules quantitatively define how TFs select the appropriate regulatory targets from a large number of similar DNA elements in the genome to elicit specific transcriptional and cellular responses. Importantly, we also demonstrate that these DNA-binding rules extend to DNA elements that do not support transcriptional activity. That is, the DNA-binding rules are obeyed, but the retention time of the TF at these non-functional DNA elements is not long enough to initiate and/or maintain transcription. We further demonstrate that IS is universal within the genome. Thus, IS is the DNA code that TFs use to interact with the genome and dictates (in conjunction with known DNA sequence constraints) which of those interactions are functionally active.

Progesterone Is Important for Transgender Women's Therapy-Applying Evidence for the Benefits of Progesterone in Ciswomen

BACKGROUND

Although the 2017 Endocrine Society Guidelines for gender dysphoria stipulated that cross-sex hormone therapy (CHT) achieve gonadal steroid levels equivalent to those of a cisperson of the chosen sex, for transgender women (male-to-female gender dysphoria), current gonadal therapy is usually estradiol. Accumulated evidence indicates that normally ovulatory menstrual cycles are necessary for ciswomen's current fertility, as well as for later-life bone and cardiovascular health and the prevention of breast and endometrial cancers.

EVIDENCE ACQUISITION

Extensive past clinical experience with transgender women's CHT using estradiol/estrogen combined with progesterone/medroxyprogesterone and pioneering the addition of spironolactone. Comprehensive progesterone physiology research plus a brief review of transgender women's literature to assess current therapy and clinical outcomes, including morbidity and mortality.

PURPOSE

To emphasize that both ovarian hormones, progesterone as well as estradiol, are theoretically and clinically important for optimal transgender women's CHT.

EVIDENCE SYNTHESIS

It is important to add progesterone to estradiol and an antiandrogen in transgender women's CHT. Progesterone may add the following: (i) more rapid feminization, (ii) decreased endogenous testosterone production, (iii) optimal breast maturation to Tanner stages 4/5, (iv) increased bone formation, (v) improved sleep and vasomotor symptom control, and (vi) cardiovascular health benefits.

CONCLUSIONS

Evidence has accrued that normal progesterone (and ovulation), as well as physiological estradiol levels, is necessary during ciswomen's premenopausal menstrual cycles for current fertility and long-term health; transgender women deserve progesterone therapy and similar potential physiological benefits.

Epithelial to Mesenchymal Transition and Cell Biology of Molecular Regulation in Endometrial Carcinogenesis

Endometrial carcinogenesis is involved in several signaling pathways and it comprises multiple steps. The four major signaling pathways-PI3K/AKT, Ras/Raf/MEK/ERK, WNT/β-catenin, and vascular endothelial growth factor (VEGF)-are involved in tumor cell metabolism, growth, proliferation, survival, and angiogenesis. The genetic mutation and germline mitochondrial DNA mutations also impair cell proliferation, anti-apoptosis signaling, and epithelial⁻mesenchymal transition by several transcription factors, leading to endometrial carcinogenesis and distant metastasis. The PI3K/AKT pathway activates the ransforming growth factor beta (TGF-β)-mediated endothelial-to-mesenchymal transition (EMT) and it interacts with downstream signals to upregulate EMT-associated factors. Estrogen and progesterone signaling in EMT also play key roles in the prognosis of endometrial carcinogenesis. In this review article, we summarize the current clinical and basic research efforts regarding the detailed molecular regulation in endometrial carcinogenesis, especially in EMT, to provide novel targets for further anti-carcinogenesis treatment.

Exploiting vulnerabilities of cancer by targeting nuclear receptors of stromal cells in tumor microenvironment

The tumor microenvironment is a complex and dynamic cellular community comprising the tumor epithelium and various tumor-supporting cells such as immune cells, fibroblasts, immunosuppressive cells, adipose cells, endothelial cells, and pericytes. The interplay between the tumor microenvironment and tumor cells represents a key contributor to immune evasiveness, physiological hardiness and the local and systemic invasiveness of malignant cells. Nuclear receptors are master regulators of physiological processes and are known to play pro-/anti-oncogenic activities in tumor cells. However, the actions of nuclear receptors in tumor-supporting cells have not been widely studied. Given the excellent druggability and extensive regulatory effects of nuclear receptors, understanding their biological functionality in the tumor microenvironment is of utmost importance. Therefore, the present review aims to summarize recent evidence about the roles of nuclear receptors in tumor-supporting cells and their implications for malignant processes such as tumor proliferation, evasion of immune surveillance, angiogenesis, chemotherapeutic resistance, and metastasis. Based on findings derived mostly from cell culture studies and a few in vivo animal cancer models, the functions of VDR, PPARs, AR, ER and GR in tumor-supporting cells are relatively well-characterized. Evidence for other receptors, such as RARβ, RORγ, and FXR, is limited yet promising. Hence, the nuclear receptor signature in the tumor microenvironment may harbor prognostic value. The clinical prospects of a tumor microenvironment-oriented cancer therapy exploiting the nuclear receptors in different tumor-supporting cells are also encouraging. The major challenge, however, lies in the ability to develop a highly specific drug delivery system to facilitate precision medicine in cancer therapy.

FGF2 induces breast cancer growth through ligand-independent activation and recruitment of ERα and PRBΔ4 isoform to MYC regulatory sequences

Progression to hormone-independent growth leading to endocrine therapy resistance occurs in a high proportion of patients with estrogen receptor alpha (ERα) and progesterone receptors (PR) positive breast cancer. We and others have previously shown that estrogen- and progestin-induced tumor growth requires ERα and PR interaction at their target genes. Here, we show that fibroblast growth factor 2 (FGF2)-induces cell proliferation and tumor growth through hormone-independent ERα and PR activation and their interaction at the MYC enhancer and proximal promoter. MYC inhibitors, antiestrogens or antiprogestins reverted FGF2-induced effects. LC-MS/MS identified 700 canonical proteins recruited to MYC regulatory sequences after FGF2 stimulation, 397 of which required active ERα (ERα-dependent). We identified ERα-dependent proteins regulating transcription that, after FGF2 treatment, were recruited to the enhancer as well as proteins involved in transcription initiation that were recruited to the proximal promoter. Also, among the ERα-dependent and independent proteins detected at both sites, PR isoforms A and B as well as the novel protein product PRBΔ4 were found. PRBΔ4 lacks the hormone-binding domain and was able to induce reporter gene expression from estrogen-regulated elements and to increase cell proliferation when cells were stimulated with FGF2 but not by progestins. Analysis of the Cancer Genome Atlas data set revealed that PRBΔ4 expression is associated with worse overall survival in luminal breast cancer patients. This discovery provides a new mechanism by which growth factor signaling can engage nonclassical hormone receptor isoforms such as PRBΔ4, which interacts with growth-factor activated ERα and PR to stimulate MYC gene expression and hence progression to endocrine resistance.

Therapeutic Efficiency of an External Chinese Herbal Formula of Mammary Precancerous Lesions by BATMAN-TCM Online Bioinformatics Analysis Tool and Experimental Validation

Ruyan Neixiao Cream (RYNXC), a patented Chinese herbal formula, was reported to have the effect of treating mammary precancerous disease. In this study, we predicted the potential targets, pathways, and diseases of the ingredients contained in each herbal of RYNXC and constructed an ingredients-targets-diseases network. Then, we analyzed molecular mechanisms of this Chinese herbal formula by MCF-10AT cells and model rats of breast precancerous lesions. BATMAN-TCM prediction showed that ESR1, PGR, PTGS2, EGFR, and Src were mRNA targets of RYNXC. Our results suggested that RYNXC transdermal fluid downregulated ESR1, PGR, PTGS2, EGFR, and Src expression at gene and protein level in MCF-10AT cells. In the rat breast precancerous lesions model, high and low dose RYNXC could also significantly reduce genes and proteins expression of ESR1, PGR, PTGS2, EGFR, and Src. Taken together these data indicate that RYNXC targets multiple molecules responsible for breast precancerous lesion and is an effective Chinese herbal formula. So RYNXC may be a promising external drug for breast precancerous lesions.

Zfhx3 is essential for progesterone/progesterone receptor signaling to drive ductal side-branching and alveologenesis in mouse mammary glands

Progesterone (Pg)/progesterone receptor (PR) signaling drives mammary gland side-branching and alveologenesis, but the mechanisms through which Pg/PR signaling functions remain to be clarified. Using in vitro and in vivo models and histological and molecular analyses, we determined the role of Zfhx3 transcription factor in mammary gland development driven by Pg/PR signaling. Postnatal deletion of Zfhx3 in mouse mammary epithelial cells attenuated side-branching morphogenesis and alveologenesis. These effects were undetectable in the absence of Pg/PR signaling. During the estrus cycle, Zfhx3 expression corresponded to that of Pg, being at the highest level at the diestrus stage; Zfhx3 deletion inhibited mammary gland branching more potently at diestrus than estrus stage. Loss of Zfhx3 not only attenuated the expansion of stem/progenitor cells driven by Pg/PR signaling, but also impaired the function of Pg/PR signaling in the transcriptional activation of multiple genes. In addition, Pg/PR signaling significantly expanded PR- and Zfhx3-positive epithelial cells, and induced the physical association of ZFHX3 with PR. These findings establish Zfhx3 as an integral transcription factor of Pg/PR signaling in driving side-branching and alveologenesis during mammary gland development.

Higher order genomic organization and epigenetic control maintain cellular identity and prevent breast cancer

Cells establish and sustain structural and functional integrity of the genome to support cellular identity and prevent malignant transformation. In this review, we present a strategic overview of epigenetic regulatory mechanisms including histone modifications and higher order chromatin organization (HCO) that are perturbed in breast cancer onset and progression. Implications for dysfunctions that occur in hormone regulation, cell cycle control, and mitotic bookmarking in breast cancer are considered, with an emphasis on epithelial-to-mesenchymal transition and cancer stem cell activities. The architectural organization of regulatory machinery is addressed within the contexts of translating cancer-compromised genomic organization to advances in breast cancer risk assessment, diagnosis, prognosis, and identification of novel therapeutic targets with high specificity and minimal off target effects.

Androgen Receptor Signalling Promotes a Luminal Phenotype in Mammary Epithelial Cells

Androgens influence mammary gland development but the specific role of the androgen receptor (AR) in mammary function is largely unknown. We identified cell subsets that express AR in vivo and determined the effect of AR activation and transgenic AR inhibition on sub-populations of the normal mouse mammary epithelium by flow cytometry and immunohistochemistry. Immunolocalisation of AR with markers of lineage identity was also performed in human breast tissues. AR activation in vivo significantly decreased the proportion of basal cells, and caused an accumulation of cells that expressed a basal cell marker but exhibited morphological features of luminal identity. Conversely, in AR null mice the proportion of basal mammary epithelial cells was significantly increased. Inhibition of AR increased basal but not luminal progenitor cell activity in vitro. A small population of AR-positive cells in a basal-to-luminal phenotype transition was also evident in human breast lobules. Collectively, these data support a role for AR in promoting a luminal phenotype in mammary epithelial cells.

Thirty years of neuroendocrinology: Technological advances pave the way for molecular discovery

Since the 1950s, the systems level interactions between the hypothalamus, pituitary and end organs such as the adrenal, thyroid and gonads have been well known; however, it is only over the last three decades that advances in molecular biology and information technology have provided a tremendous expansion of knowledge at the molecular level. Neuroendocrinology has benefitted from developments in molecular genetics, epigenetics and epigenomics, and most recently optogenetics and pharmacogenetics. This has enabled a new understanding of gene regulation, transcription, translation and post-translational regulation, which should help direct the development of drugs to treat neuroendocrine-related diseases.

Estradiol and progesterone regulate proliferation and apoptosis in colon cancer

Epidemiological studies describe estrogens as protectors in the development of colon cancer in postmenopausal women treated with hormone replacement therapy. However, the role of progesterone in colon cancer has been minimally studied and the results are controversial. For the above, the objective of this work was to determine the hormonal regulation exerted by natural ovarian steroids on proliferation and apoptosis in an experimental model of colon cancer in ovariectomized rats treated with 17-beta estradiol and progesterone. Sprague-Dawley rats were exposed to the carcinogen 1,2-dimethylhydrazine to induce colon tumors. Thirty days later, the rats were ovariectomized and treated with estradiol (60 μg/kg), progesterone (10 mg/kg), estradiol plus progesterone (60 μg/kg and 10 mg/kg) or vehicle. We observed no significant differences in colon cancer incidence and tumor multiplicity between the groups. Nevertheless, we observed a decrease in PCNA expression and a greater number of apoptotic index, higher expression of caspase 3, cleaved PARP and cleaved caspase 8 in tumors, confirming the activation of the extrinsic pathway of apoptosis by the combined treatment. In addition, we observed a higher expression of estrogen receptor beta in these tumors. We conclude that the action of both hormones, estradiol and progesterone, is necessary to reduce proliferation and increase apoptosis in colon tumors, probably through estrogen receptor beta activation.

Progesterone reduces cell survival in primary cultures of endometrioid ovarian cancer

BACKGROUND

Ovarian cancer is the most lethal of all gynecologic malignancies. The relationship between sexual steroids receptors and ovarian cancer progression has been largely evaluated. The presence of progesterone receptors has been associated with an increase of a disease-free period and overall survival in patients with ovarian carcinoma. In the present study, primary cultures of ovarian carcinoma obtained from 35 patients diagnosed with epithelial ovarian cancer were evaluated for cell survival after treatment with 10- 8 M of 17β-estradiol, progesterone, testosterone and dihydrotestosterone.

RESULTS

The results were analyzed considering histological subtypes: low grade serous, high grade serous, endometrioid and mucinous carcinoma; clear cell carcinoma was not included due to failure in obtaining successful cultures of this subtype. A significant reduction of cell survival was observed after progesterone treatment in endometrioid ovarian carcinoma. Changes were not observed in low grade serous, high grade serous and mucinous carcinoma. The effect of progesterone was related to the presence of progesterone receptor (PR), a 43% reduction in the cell number was observed in PR (+) endometrioid ovarian carcinoma.

CONCLUSIONS

This study supports the importance of progesterone and the presence of progesterone receptor in the reduction of ovarian cancer progression in the endometrioid ovarian carcinoma.

Estrogen Signaling in Endometrial Cancer: a Key Oncogenic Pathway with Several Open Questions

Endometrial cancer is the most common gynecological cancer in the developed world, and it is one of the few cancer types that is becoming more prevalent and leading to more deaths in the USA each year. The majority of endometrial tumors are considered to be hormonally driven, where estrogen signaling through estrogen receptor α (ER) acts as an oncogenic signal. The major risk factors and some treatment options for endometrial cancer patients emphasize a key role for estrogen signaling in the disease. Despite the strong connections between estrogen signaling and endometrial cancer, important molecular aspects of ER function remain poorly understood; however, progress is being made in our understanding of estrogen signaling in endometrial cancer. Here, we discuss the evidence for the importance of estrogen signaling in endometrial cancer, details of the endometrial cancer-specific actions of ER, and open questions surrounding estrogen signaling in endometrial cancer.

Phosphorylated Progesterone Receptor Isoforms Mediate Opposing Stem Cell and Proliferative Breast Cancer Cell Fates

Progesterone receptors (PRs) are key modifiers of estrogen receptor (ER) target genes and drivers of luminal breast cancer progression. Total PR expression, rather than isoform-specific PR expression, is measured in breast tumors as an indicator of functional ER. We identified phenotypic differences between PR-A and PR-B in luminal breast cancer models with a focus on tumorsphere biology. Our findings indicated that PR-A is a dominant driver of cancer stem cell (CSC) expansion in T47D models, and PR-B is a potent driver of anchorage-independent proliferation. PR-A+ tumorspheres were enriched for aldehyde dehydrogenase (ALDH) activity, CD44+/CD24-, and CD49f+/CD24- cell populations relative to PR-B+ tumorspheres. Progestin promoted heightened expression of known CSC-associated target genes in PR-A+ but not PR-B+ cells cultured as tumorspheres. We report robust phosphorylation of PR-A relative to PR-B Ser294 and found that this residue is required for PR-A-induced expression of CSC-associated genes and CSC behavior. Cells expressing PR-A S294A exhibited impaired CSC phenotypes but heightened anchorage-independent cell proliferation. The PR target gene and coactivator, FOXO1, promoted PR phosphorylation and tumorsphere formation. The FOXO1 inhibitor (AS1842856) alone or combined with onapristone (PR antagonist), blunted phosphorylated PR, and tumorsphere formation in PR-A+ and PR-B+ T47D, MCF7, and BT474 models. Our data revealed unique isoform-specific functions of phosphorylated PRs as modulators of distinct and opposing pathways relevant to mechanisms of late recurrence. A clear understanding of PR isoforms, phosphorylation events, and the role of cofactors could lead to novel biomarkers of advanced tumor behavior and reveal new approaches to pharmacologically target CSCs in luminal breast cancer.

Inhibition of histone methyltransferase DOT1L silences ERα gene and blocks proliferation of antiestrogen-resistant breast cancer cells

Breast cancer (BC) resistance to endocrine therapy results from constitutively active or aberrant estrogen receptor α (ERα) signaling, and ways to block ERα pathway in these tumors are sought after. We identified the H3K79 methyltransferase DOT1L as a novel cofactor of ERα in BC cell chromatin, where the two proteins colocalize to regulate estrogen target gene transcription. DOT1L blockade reduces proliferation of hormone-responsive BC cells in vivo and in vitro, consequent to cell cycle arrest and apoptotic cell death, with widespread effects on ER-dependent gene transcription, including ERα and FOXA1 gene silencing. Antiestrogen-resistant BC cells respond to DOT1L inhibition also in mouse xenografts, with reduction in ERα levels, H3K79 methylation, and tumor growth. These results indicate that DOT1L is an exploitable epigenetic target for treatment of endocrine therapy-resistant ERα-positive BCs.

The association between progesterone receptor expression and survival in women with adult granulosa cell tumors

BACKGROUND

Granulosa cell tumors (GCT) variably express estrogen receptors (ER) and progesterone receptors (PR). The goal of this study is to evaluate the relationship between ER and PR expression patterns and clinical outcomes in women with GCT.

METHODS

A multicenter, retrospective analysis was performed of all cases of GCT diagnosed between 1989 and 2012. Immunohistochemical staining for ER and PR was performed on formalin-fixed paraffin embedded (FFPE) tumor tissue and interpreted using a semiquantitative scoring system that incorporated tumor cell staining proportion and intensity. Demographics, disease status, and survival information were collected. Associations between ER and PR staining scores and recurrence-free and overall survival were assessed using univariate Cox proportional hazards models.

RESULTS

FFPE tumor blocks were available for 149/186 GCT patients. The majority of the women had clinical stage I disease (76%). ER and PR expression was present in 52% and 98% of subjects, respectively. The median composite scores of ER and PR staining were 1 (range 0-8) and 9 (range 0-15), respectively. In univariate analysis, PR composite score >9 was strongly associated with decreased recurrence-free survival (HR = 2.9, 95% CI = 1.5-5.5) and decreased overall survival (HR = 3.7, CI 1.3-10.2). ER composite score was not a significant predictor of recurrence-free survival or overall survival (p = 0.7, HR = 1.1, 95% CI 0.6-2.0 and p = 0.06, HR = 1.1, 95% CI 0.4-2.9, respectively).

CONCLUSIONS

Our results reveal that high PR composite score (≥9) was associated with both decreased recurrence-free and overall survival in patients with GCT while ER expression was not associated with survival outcomes.

Effects of serum estradiol and progesterone on estrogen-regulated gene expression in breast cancers of premenopausal patients

Background

Expression of estrogen receptor α in breast cancer is essential for estrogen-dependent growth and partially determines the breast cancer subtype. In premenopausal women, expression of estrogen-regulated genes in estrogen receptor-positive breast cancer tissues are reportedly influenced by the menstrual cycle.

Methods

We investigated correlations between serum estradiol (E2; tested on the day of surgery) and expression of estrogen-regulated genes and proliferation genes in strongly estrogen receptor α-positive breast cancer tissues from 91 premenopausal women by quantitative reverse transcription-polymerase chain reaction. We also investigated correlations between serum progesterone levels on the day of surgery and mRNA expression of progesterone-regulated genes and proliferation genes.

Results

The serum E2 level affected expression of estrogen-regulated genes, including progesterone receptor (P = 0.016, Rs = 0.07) but showed no correlation with expression of genes associated with proliferation. We also observed strong positive correlations between mRNA expression of ESR1 and that of estrogen-regulated genes (P < 0.0001, Rs = 0.329-0.756) and proliferation genes (P < 0.0001, Rs = 0.753-0.843). The serum progesterone level affected expression of RANKL mRNA. However, we observed no correlations between serum progesterone and expression of Wnt-4 or proliferation genes.

Conclusions

The serum E2 level on the day of surgery influences estrogen-regulated gene expression moderately in patients found to be strongly positive for estrogen receptor α by immunohistochemistry. Changes in serum E2 levels might influence the results of molecular profiling tests in premenopausal women with breast cancer.

Endocrine Resistance in Hormone Receptor Positive Breast Cancer-From Mechanism to Therapy

The importance and role of the estrogen receptor (ER) pathway has been well-documented in both breast cancer (BC) development and progression. The treatment of choice in women with metastatic breast cancer (MBC) is classically divided into a variety of endocrine therapies, 3 of the most common being: selective estrogen receptor modulators (SERM), aromatase inhibitors (AI) and selective estrogen receptor down-regulators (SERD). In a proportion of patients, resistance develops to endocrine therapy due to a sophisticated and at times redundant interference, at the molecular level between the ER and growth factor. The progression to endocrine resistance is considered to be a gradual, step-wise process. Several mechanisms have been proposed but thus far none of them can be defined as the complete explanation behind the phenomenon of endocrine resistance. Although multiple cellular, molecular and immune mechanisms have been and are being extensively studied, their individual roles are often poorly understood. In this review, we summarize current progress in our understanding of ER biology and the molecular mechanisms that predispose and determine endocrine resistance in breast cancer patients.

Hormone-control regions mediate steroid receptor-dependent genome organization

In breast cancer cells, some topologically associating domains (TADs) behave as hormonal gene regulation units, within which gene transcription is coordinately regulated in response to steroid hormones. Here we further describe that responsive TADs contain 20- to 100-kb-long clusters of intermingled estrogen receptor (ESR1) and progesterone receptor (PGR) binding sites, hereafter called hormone-control regions (HCRs). In T47D cells, we identified more than 200 HCRs, which are frequently bound by unliganded ESR1 and PGR. These HCRs establish steady long-distance inter-TAD interactions between them and organize characteristic looping structures with promoters in their TADs even in the absence of hormones in ESR1⁺-PGR⁺ cells. This organization is dependent on the expression of the receptors and is further dynamically modulated in response to steroid hormones. HCRs function as platforms that integrate different signals, resulting in some cases in opposite transcriptional responses to estrogens or progestins. Altogether, these results suggest that steroid hormone receptors act not only as hormone-regulated sequence-specific transcription factors but also as local and global genome organizers.

Up-regulation of the kinase gene SGK1 by progesterone activates the AP-1-NDRG1 axis in both PR-positive and -negative breast cancer cells

Preoperative progesterone intervention has been shown to confer a survival benefit to breast cancer patients independently of their progesterone receptor (PR) status. This observation raises the question how progesterone affects the outcome of PR-negative cancer. Here, using microarray and RNA-Seq-based gene expression profiling and ChIP-Seq analyses of breast cancer cells, we observed that the serum- and glucocorticoid-regulated kinase gene (SGK1) and the tumor metastasis-suppressor gene N-Myc downstream regulated gene 1 (NDRG1) are up-regulated and that the microRNAs miR-29a and miR-101-1 targeting the 3'-UTR of SGK1 are down-regulated in response to progesterone. We further demonstrate a dual-phase transcriptional and post-transcriptional regulation of SGK1 in response to progesterone, leading to an up-regulation of NDRG1 that is mediated by a set of genes regulated by the transcription factor AP-1. We found that NDRG1, in turn, inactivates a set of kinases, impeding the invasion and migration of breast cancer cells. In summary, we propose a model for the mode of action of progesterone in breast cancer. This model helps decipher the molecular basis of observations in a randomized clinical trial of the effect of progesterone on breast cancer and has therefore the potential to improve the prognosis of breast cancer patients receiving preoperative progesterone treatment.

The evolving role of receptors as predictive biomarkers for metastatic breast cancer

INTRODUCTION

In breast cancer, estrogen receptor (ER) and human epidermal growth factor receptor 2 (HER2) are essential biomarkers to predict response to endocrine and anti-HER2 therapies, respectively. In metastatic breast cancer, the use of these receptors and targeted therapies present additional challenges: temporal heterogeneity, together with limited sampling methodologies, hinders receptor status assessment, and the constant evolution of the disease invariably leads to resistance to treatment. Areas covered: This review summarizes the genomic abnormalities in ER and HER2, such as mutations, amplifications, translocations, and alternative splicing, emerging as novel biomarkers that provide an insight into underlying mechanisms of resistance and hold potential predictive value to inform treatment selection. We also describe how liquid biopsies for sampling of circulating markers and ultrasensitive detection technologies have emerged which complement ongoing efforts for biomarker discovery and analysis. Expert commentary: While evidence suggests that genomic aberrations in ER and HER2 could contribute to meeting the pressing need for better predictive biomarkers, efforts need to be made to standardize assessment methods and better understand the resistance mechanisms these markers denote. Taking advantage of emerging technologies, research in upcoming years should include prospective trials incorporating these predictors into the study design to validate their potential clinical value.

New Opportunities for Targeting the Androgen Receptor in Prostate Cancer

Recent genomic analyses of metastatic prostate cancer have provided important insight into adaptive changes in androgen receptor (AR) signaling that underpin resistance to androgen deprivation therapies. Novel strategies are required to circumvent these AR-mediated resistance mechanisms and thereby improve prostate cancer survival. In this review, we present a summary of AR structure and function and discuss mechanisms of AR-mediated therapy resistance that represent important areas of focus for the development of new therapies.

Deciphering Steroid Receptor Crosstalk in Hormone-Driven Cancers

Steroid hormone receptors (SRs) have a multitude of functions in human biology and disease progression. The SR family of related ligand-activated transcription factors includes androgen, estrogen, glucocorticoid, mineralocorticoid, and progesterone receptors. Antiestrogen or estrogen receptor (ER)-targeted therapies to block ER action remain the primary treatment of luminal breast cancers. Although this strategy is successful, ∼40% of patients eventually relapse due to endocrine resistance. The majority of hormone-independent tumors retain some level of SR expression, but sidestep hormone ablation treatments. SRs are known to crosstalk extensively with kinase signaling pathways, and this interplay has been shown to bypass ER-targeted therapies in part by providing alternative proliferation and survival signals that enable hormone independence. Modified receptors adopt alternate conformations that resist antagonism or promote agonism. SR-regulated transcription and SR-binding events have been classically studied as single receptor events using single hormones. However, it is becoming increasingly evident that individual steroids and SRs rarely act alone. Emerging evidence shows that coexpressed SRs crosstalk with each other in hormone-driven cancers, such as breast and prostate. Crosstalk between related SRs allows them to modulate signaling and transcriptional responses to noncognate ligands. This flexibility can lead to altered genomic binding and subsequent changes in SR target gene expression. This review will discuss recent mechanistic advances in elucidating SR crosstalk and the implications for treating hormone-driven cancers. Understanding this crosstalk (i.e., both opposing and collaborative) is a critical step toward expanding and modernizing endocrine therapies and will ultimately improve patient outcomes.

The Emerging Roles of Steroid Hormone Receptors in Ductal Carcinoma in Situ (DCIS) of the Breast

Ductal carcinoma in situ (DCIS) is a non-obligate precursor to most types of invasive breast cancer (IBC). Although it is estimated only one third of untreated patients with DCIS will progress to IBC, standard of care for treatment is surgery and radiation. This therapeutic approach combined with a lack of reliable biomarker panels to predict DCIS progression is a major clinical problem. DCIS shares the same molecular subtypes as IBC including estrogen receptor (ER) and progesterone receptor (PR) positive luminal subtypes, which encompass the majority (60-70%) of DCIS. Compared to the established roles of ER and PR in luminal IBC, much less is known about the roles and mechanism of action of estrogen (E2) and progesterone (P4) and their cognate receptors in the development and progression of DCIS. This is an underexplored area of research due in part to a paucity of suitable experimental models of ER+/PR + DCIS. This review summarizes information from clinical and observational studies on steroid hormones as breast cancer risk factors and ER and PR as biomarkers in DCIS. Lastly, we discuss emerging experimental models of ER+/PR+ DCIS.

Disabled-1 is down-regulated in clinical breast cancer and regulates cell apoptosis through NF-κB/Bcl-2/caspase-9

Disabled‐1 (Dab1) is best known as an adaptor protein regulating neuron migration and lamination during development. However, the exact function of Dab1 in breast cancer is unknown. In this study, we examined the expression of Dab1 in 38 breast cancer paraffin sections, as well as 60 paired frozen breast cancer and their adjacent tissues. Our results showed that Dab1 was reduced in breast cancer, and its compromised expression correlated with triple negative breast cancer phenotype, poor differentiation, as well as lymph node metastasis. Functional analysis in breast cancer cell lines demonstrated that Dab1 promoted cell apoptosis, which, at least partially, depended on its regulation of NF‐κB/Bcl‐2/caspase‐9 pathway. Our study strongly suggests that Dab1 may be a potential tumour suppressor gene in breast cancer.

Oestrogen receptor α AF-1 and AF-2 domains have cell population-specific functions in the mammary epithelium

Oestrogen receptor α (ERα) is a transcription factor with ligand-independent and ligand-dependent activation functions (AF)-1 and -2. Oestrogens control postnatal mammary gland development acting on a subset of mammary epithelial cells (MECs), termed sensor cells, which are ERα-positive by immunohistochemistry (IHC) and secrete paracrine factors, which stimulate ERα-negative responder cells. Here we show that deletion of AF-1 or AF-2 blocks pubertal ductal growth and subsequent development because both are required for expression of essential paracrine mediators. Thirty percent of the luminal cells are ERα-negative by IHC but express Esr1 transcripts. This low level ERα expression through AF-2 is essential for cell expansion during puberty and growth-inhibitory during pregnancy. Cell-intrinsic ERα is not required for cell proliferation nor for secretory differentiation but controls transcript levels of cell motility and cell adhesion genes and a stem cell and epithelial mesenchymal transition (EMT) signature identifying ERα as a key regulator of mammary epithelial cell plasticity.

Oestrogen receptors α (ERα) are expressed in a subset of mammary epithelial cells. Here, the authors identify cells with low-ERα protein levels and show that distinct cell populations have distinct requirements for the AF1 and AF2 domains of the ERα, and ERα acts in a biphasic manner dependent on developmental stage.

Nomogram for predicting preoperative lymph node involvement in patients with invasive micropapillary carcinoma of breast: a SEER population-based study

BACKGROUND

Invasive micropapillary carcinoma (IMPC) is an unusual and distinct subtype of invasive breast tumor with high propensity for regional lymph node metastases. This study was to identify risk factors accounting for IMPC of the breast and to develop a nomogram to preoperatively predict the probability of lymph node involvement.

METHODS

A retrospective review of the clinical and pathology records was performed in patients diagnosed with IMPC between 2003 and 2014 from Surveillance, Epidemiology, and End Results (SEER) database. The cohort was divided into training and validation sets. Training set comprised patients diagnosed between 2003 and 2009, while validation set included patients diagnosed thereafter. A logistic regression model was used to construct the nomogram in the training set and then varified in the validation set. Nomogram performance was quantified with respect to discrimination and calibration using R 3.4.1 software.

RESULTS

Overall, 1407 patients diagnosed with IMPC were enrolled, of which 527 in training set and 880 in validation set. Logistic regression analysis indicated larger lesions, younger age at diagnosis, black ethnic and lack of hormone receptor expression were significantly related to regional nodes involvement. The AUC of the nomogram was 0.735 (95% confidential interval (CI) 0.692 to 0.777), demonstrating a good prediction performance. Calibration curve for the nomogram was plotted and the slope was close to 1, which demonstrated excellent calibration of the nomogram. The performance of the nomogram was further validated in the validation set, with AUC of 0.748 (95% CI 0.701 to 0.767).

CONCLUSIONS

The striking difference between IMPC and IDC remains the increased lymph node involvement in IMPC and therefore merits aggressive treatment. The nomogram based on the clinicalpathologic parameters was established, which could accurately preoperatively predict regional lymph node status. This nomogram would facilitate evaluating lymph node state preoperatively and thus treatment decision-making of individual patients.

Signaling Pathways Induced by Leptin during Epithelial⁻Mesenchymal Transition in Breast Cancer

Leptin is an adipokine that is overexpressed in obese and overweight people. Interestingly, women with breast cancer present high levels of leptin and of its receptor ObR. Leptin plays an important role in breast cancer progression due to the biological processes it participates in, such as epithelial⁻mesenchymal transition (EMT). EMT consists of a series of orchestrated events in which cell⁻cell and cell⁻extracellular matrix interactions are altered and lead to the release of epithelial cells from the surrounding tissue. The cytoskeleton is also re-arranged, allowing the three-dimensional movement of epithelial cells into the extracellular matrix. This transition provides cells with the ability to migrate and invade adjacent or distal tissues, which is a classic feature of invasive or metastatic carcinoma cells. In recent years, the number of cases of breast cancer has increased, making this disease a public health problem worldwide and the leading cause of death due to cancer in women. In this review, we focus on recent advances that establish: (1) leptin as a risk factor for the development of breast cancer, and (2) leptin as an inducer of EMT, an event that promotes tumor progression.

Improved relapse-free survival on aromatase inhibitors in breast cancer is associated with interaction between oestrogen receptor-α and progesterone receptor-b

BACKGROUND

Recent pre-clinical studies indicate that activated progesterone receptor (PR) (particularly the PR-B isoform) binds to oestrogen receptor-α (ER) and reprogrammes transcription toward better breast cancer outcomes. We investigated whether ER and PR-B interactions were present in breast tumours and associated with clinical parameters including response to aromatase inhibitors.

METHODS

We developed a proximity ligation assay to detect ER and PR-B (ER:PR-B) interactions in formalin-fixed paraffin-embedded tissues. The assay was validated in a cell line and patient-derived breast cancer explants and applied to a cohort of 229 patients with ER-positive and HER2-negative breast cancer with axillary nodal disease.

RESULTS

Higher frequency of ER:PR-B interaction correlated with increasing patient age, lower tumour grade and mitotic index. A low frequency of ER:PR-B interaction was associated with higher risk of relapse. In multivariate analysis, ER:PR-B interaction frequency was an independent predictive factor for relapse, whereas PR expression was not. In subset analysis, low frequency of ER:PR-B interaction was predictive of relapse on adjuvant aromatase inhibitor (HR 4.831, p = 0.001), but not on tamoxifen (HR 1.043, p = 0.939).

CONCLUSIONS

This study demonstrates that ER:PR-B interactions have utility in predicting patient response to adjuvant AI therapy.

The Divergent Function of Androgen Receptor in Breast Cancer; Analysis of Steroid Mediators and Tumor Intracrinology

Androgen receptor (AR) is the most widely expressed steroid receptor protein in normal breast tissue and is detectable in approximately 90% of primary breast cancers and 75% of metastatic lesions. However, the role of AR in breast cancer development and progression is mired in controversy with evidence suggesting it can either inhibit or promote breast tumorigenesis. Studies have shown it to antagonize estrogen receptor alpha (ERα) DNA binding, thereby preventing pro-proliferative gene transcription; whilst others have demonstrated AR to take on the mantle of a pseudo ERα particularly in the setting of triple negative breast cancer. Evidence for a potentiating role of AR in the development of endocrine resistant breast cancer has also been mounting with reports associating high AR expression with poor response to endocrine treatment. The resurgence of interest into the function of AR in breast cancer has resulted in various emergent clinical trials evaluating anti-AR therapy and selective androgen receptor modulators in the treatment of advanced breast cancer. Trials have reported varied response rates dependent upon subtype with overall clinical benefit rates of ~19-29% for anti-androgen monotherapy, suggesting that with enhanced patient stratification AR could prove efficacious as a breast cancer therapy. Androgens and AR have been reported to facilitate tumor stemness in some cancers; a process which may be mediated through genomic or non-genomic actions of the AR, with the latter mechanism being relatively unexplored in breast cancer. Steroidogenic ligands of the AR are produced in females by the gonads and as sex-steroid precursors secreted from the adrenal glands. These androgens provide an abundant reservoir from which all estrogens are subsequently synthesized and their levels are undiminished in the event of standard hormonal therapeutic intervention in breast cancer. Steroid levels are known to be altered by lifestyle factors such as diet and exercise; understanding their potential role in dictating the function of AR in breast cancer development could therefore have wide-ranging effects in prevention and treatment of this disease. This review will outline the endogenous biochemical drivers of both genomic and non-genomic AR activation and how these may be modulated by current hormonal therapies.

Co-expression of nuclear P38 and hormone receptors is prognostic of good long-term clinical outcome in primary breast cancer and is linked to upregulation of DNA repair

Background

P38 mitogen activated protein kinase is an intermediary signal transduction factor with context-specific roles in breast cancer. Recent mechanistic studies add to the growing consensus that P38 is a tumour suppressor, and it may represent a novel target for breast cancer treatment. The aim of this study is to add definitive data on the prognostic value of P38 and its link with biomarkers in primary breast cancer.

Methods

A large, well-characterised series of 1332 primary breast cancer patients with long-term clinical follow-up was assessed for P38 expression by immunohistochemistry. Association of clinicopathological factors and a panel of breast cancer biomarkers was determined by chi-squared test, and multivariate survival analysis was performed using Cox Proportional Hazards regression modelling.

Results

This study shows that nuclear P38 is co-expressed with nuclear hormone receptors (p < 0.001) and is an independent prognostic marker of good long-term clinical outcome in primary breast cancer (hazard ratio 0.796, 95% confidence interval 0.662–0.957, p = 0.015). Significant association was found between expression of P38 and markers of DNA repair including nuclear BRCA1 and RAD51, and cleaved PARP1 (all p < 0.001).

Conclusions

The findings support the proposed role for P38 as a tumour suppressor in breast cancer via upregulation of DNA repair proteins and provide novel hypothesis-generating information on the potential role of P38 in adjuvant therapy decision making.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4924-2) contains supplementary material, which is available to authorized users.

Hormone Therapy and Breast Cancer: Emerging Steroid Receptor Mechanisms

Although hormone therapy is widely used by millions of women to relieve symptoms of menopause, it has been associated with several side-effects such as coronary heart disease, stroke and increased invasive breast cancer risk. These side-effects have caused many women to seek alternatives to conventional hormone therapy, including the controversial custom-compounded bioidentical hormone therapy suggested to not increase breast cancer risk. Historically estrogens and the estrogen receptor were considered the principal factors promoting breast cancer development and progression, however, a role for other members of the steroid receptor family in breast cancer pathogenesis is now evident, with emerging studies revealing an interplay between some steroid receptors. In this review, we discuss examples of hormone therapy used for the relief of menopausal symptoms, highlighting the distinction between conventional hormone therapy and custom-compounded bioidentical hormone therapy. Moreover, we highlight the fact that not all hormones have been evaluated for an association with increased breast cancer risk. We also summarize the current knowledge regarding the role of steroid receptors in mediating the carcinogenic effects of hormones used in menopausal hormone therapy, with special emphasis on the influence of the interplay or crosstalk between steroid receptors. Unraveling the intertwined nature of steroid hormone receptor signaling pathways in breast cancer biology is of utmost importance, considering that breast cancer is the most prevalent cancer among women worldwide. Moreover, understanding these mechanisms may reveal novel prevention or treatment options, and lead to the development of new hormone therapies that does not cause increased breast cancer risk.

Phase I study of onapristone, a type I antiprogestin, in female patients with previously treated recurrent or metastatic progesterone receptor-expressing cancers

INTRODUCTION

Onapristone is a type I progesterone receptor (PR) antagonist, which prevents PR- mediated DNA transcription. Onapristone is active in multiple preclinical models and two prior studies demonstrated promising activity in patients with breast cancer. We conducted a study of extended release (ER) Onapristone to determine a recommended dose and explore the role of transcriptionally-activated PR (APR), detected as an aggregated subnuclear distribution pattern, as a predictive biomarker.

METHODS

An open-label, multicenter, randomized, parallel-group, phase 1 study (target n = 60; NCT02052128) included female patients ≥18 years with PRpos tumors. APR analysis was performed on archival tumor tissue. Patients were randomized to five cohorts of extended release (ER) onapristone tablets 10, 20, 30, 40 or 50 mg BID, or immediate release 100 mg QD until progressive disease or intolerability. Primary endpoint was to identify the recommended phase 2 dose. Secondary endpoints included safety, clinical benefit and pharmacokinetics.

RESULTS

The phase 1 dose escalation component of the study is complete (n = 52). Tumor diagnosis included: endometrial carcinoma 12; breast cancer 20; ovarian cancer 13; other 7. Median age was 64 (36-84). No dose limiting toxicity was observed with reported liver function test elevation related only to liver metastases. The RP2D was 50 mg ER BID. Median therapy duration was 8 weeks (range 2-44), and 9 patients had clinical benefit ≥24 weeks, including 2 patients with APRpos endometrial carcinoma.

CONCLUSION

Clinical benefit with excellent tolerance was seen in heavily pretreated patients with endometrial, ovarian and breast cancer. The data support the development of Onapristone in endometrial endometrioid cancer. Onapristone should also be evaluated in ovarian and breast cancers along with APR immunohistochemistry validation.

XenofilteR: computational deconvolution of mouse and human reads in tumor xenograft sequence data

BACKGROUND

Mouse xenografts from (patient-derived) tumors (PDX) or tumor cell lines are widely used as models to study various biological and preclinical aspects of cancer. However, analyses of their RNA and DNA profiles are challenging, because they comprise reads not only from the grafted human cancer but also from the murine host. The reads of murine origin result in false positives in mutation analysis of DNA samples and obscure gene expression levels when sequencing RNA. However, currently available algorithms are limited and improvements in accuracy and ease of use are necessary.

RESULTS

We developed the R-package XenofilteR, which separates mouse from human sequence reads based on the edit-distance between a sequence read and reference genome. To assess the accuracy of XenofilteR, we generated sequence data by in silico mixing of mouse and human DNA sequence data. These analyses revealed that XenofilteR removes > 99.9% of sequence reads of mouse origin while retaining human sequences. This allowed for mutation analysis of xenograft samples with accurate variant allele frequencies, and retrieved all non-synonymous somatic tumor mutations.

CONCLUSIONS

XenofilteR accurately dissects RNA and DNA sequences from mouse and human origin, thereby outperforming currently available tools. XenofilteR is open source and available at https://github.com/PeeperLab/XenofilteR .

Mechanism of Telapristone Acetate (CDB4124) on Progesterone Receptor Action in Breast Cancer Cells

Progesterone is a steroid hormone that plays an important role in the breast. Progesterone exerts its action through binding to progesterone receptor (PR), a transcription factor. Deregulation of the progesterone signaling pathway is implicated in the formation, development, and progression of breast cancer. Next-generation selective progesterone receptor modulators (SPRMs) have potent antiprogestin activity and are selective for PR, reducing the off-target effects on other nuclear receptors. To date, there is limited information on how the newer generation of SPRMs, specifically telapristone acetate (TPA), affect PR function at the molecular level. In this study, T47D breast cancer cells were used to investigate the molecular mechanism by which TPA antagonizes PR action. Global profiling of the PR cistrome and interactome was done with chromatin immunoprecipitation sequencing (ChIP-seq) and rapid immunoprecipitation mass spectrometry. Validation studies were done on key genes and interactions. Our results demonstrate that treatment with the progestin (R5020) alone resulted in robust PR recruitment to the chromatin, and addition of TPA reduced PR recruitment globally. TPA significantly changed coregulator recruitment to PR compared with R5020. Upon conservative analysis, three proteins (TRPS1, LASP1, and AP1G1) were identified in the R5020+TPA-treated group. Silencing TRPS1 with small interfering RNA increased PR occupancy to the known PR regulatory regions and attenuated the inhibition of gene expression after TPA treatment. TRPS1 silencing alleviated the inhibition of proliferation by TPA. In conclusion, TPA decreases PR occupancy on chromatin and recruits coregulators such as TRPS1 to the PR complex, thereby regulating PR target gene expression and associated cellular responses.

Oestrogenic activity of mimosine on MCF-7 breast cancer cell line through the ERα-mediated pathway

Hormone replacement therapy has been a conventional treatment for postmenopausal symptoms in women. However, it has potential risks of breast and endometrial cancers. The aim of this study was to evaluate the oestrogenicity of a plant-based compound, mimosine, in MCF-7 cells by in silico model. Cell viability and proliferation, ERα-SRC1 coactivator activity and expression of specific ERα-dependent marker TFF1 and PGR genes were evaluated. Binding modes of 17β-oestradiol and mimosine at the ERα ligand binding domain were compared using docking and molecular dynamics simulation experiments followed by binding interaction free energy calculation with molecular mechanics/Poisson-Boltzmann surface area. Mimosine showed increased cellular viability (64,450 cells/ml) at 0.1 μM with significant cell proliferation (120.5%) compared to 17β-oestradiol (135.2%). ER antagonist tamoxifen significantly reduced proliferative activity mediated by mimosine (49.9%). Mimosine at 1 μM showed the highest ERα binding activity through increased SRC1 recruitment at 186.9%. It expressed TFF1 (11.1-fold at 0.1 μM) and PGR (13.9-fold at 0.01 μM) genes. ERα-mimosine binding energy was -49.9 kJ/mol, and it interacted with Thr347, Gly521 and His524 of ERα-LBD. The results suggested that mimosine has oestrogenic activity.

JMJD6 regulates histone H2A.X phosphorylation and promotes autophagy in triple-negative breast cancer cells via a novel tyrosine kinase activity

Overexpression of Jumonji domain-containing 6 (JMJD6) has been reported to be associated with more aggressive breast cancer characteristics. However, the precise role of JMJD6 in breast cancer development remains unclear. Here, we demonstrate that JMJD6 has intrinsic tyrosine kinase activity and can utilize ATP and GTP as phosphate donors to phosphorylate Y39 of histone H2A.X (H2A.X^Y39ph). High JMJD6 levels promoted autophagy in triple negative breast cancer (TNBC) cells by regulating the expression of autophagy-related genes. The JMJD6-H2A.X^Y39ph axis promoted TNBC cell growth via the autophagy pathway. We show that combined inhibition of JMJD6 kinase activity and autophagy efficiently decreases TNBC growth. Together, these findings suggest an effective strategy for TNBC treatment.