Expression of thyroid hormone receptor/erbA genes is altered in human breast cancer

Positive Progesterone Receptor Expression in Meningioma May Increase the Transverse Relaxation: First Prospective Clinical Trial Using Single-Shot Ultrafast T2 Mapping

RATIONALE AND OBJECTIVES

This project aims to investigate the diagnostic performance of multiple overlapping-echo detachment imaging (MOLED) technique-derived transverse relaxation time (T2) maps in predicting progesterone receptor (PR) and S100 expression in meningiomas.

MATERIALS AND METHODS

63 meningioma patients were enrolled from October 2021 to August 2022, who underwent a complete routine magnetic resonance imaging and T2 MOLED, which can characterize the whole brain transverse relaxation time within 32 seconds in a single scan. After the surgical resection of meningiomas, the expression levels of PR and S100 were determined by an experienced pathologist using immunohistochemistry techniques. Histogram analysis was performed in tumor parenchyma based on the parametric maps. Independent t test and Mann-Whitney U test were applied for the comparison of histogram parameters between different groups, with a significance level of P < .05. Logistic regression and receiver operating characteristic (ROC) analysis with 95% confidence interval were conducted for the diagnostic efficiency evaluation.

RESULTS

PR-positive group had significantly elevated T2 histogram parameters (P = .001-.049) compared to the PR-negative group. The multivariate logistic regression model with T2 showed the highest area under the ROC curve (AUC) for predicting PR expression (AUC=0.818). Additionally, the multivariate model also had the best diagnostic performance for predicting meningioma S100 expression (AUC=0.768).

CONCLUSION

The MOLED technique-derived T2 maps can distinguish PR and S100 status in meningiomas preoperatively.

Risk prediction of second primary malignant tumor in primary differentiated thyroid cancer patients: a population-based study

PURPOSE

To investigate the risk factors of second primary malignant tumor (SPMT) in patients with differentiated thyroid cancer (DTC) and establish a competing risk nomogram to predict the probability of SPMT occurrence.

METHODS

We retrieved data from the Surveillance, Epidemiology, and End Results (SEER) database for patients diagnosed with DTC between 2000 and 2019. The Fine and Gray subdistribution hazard model was employed to identify SPMT risk factors in the training set and develop a competing risk nomogram. Model evaluation was performed using area under the receiver operating characteristic curve (AUC), calibration curve, and decision curve analysis (DCA).

RESULTS

A total of 112,257 eligible patients were included in the study and randomized into a training set (n = 112,256) and a validation set (n = 33,678). The cumulative incidence rate of SPMT was 15% (n = 9528). Age, sex, race, tumor multifocality, and TNM stage were independent risk factors of SPMT. The calibration plots showed good agreement between the predicted and observed SPMT risks. The 10-year AUCs of the calibration plots were 70.2 (68.7-71.6) in the training set and 70.2 (68.7-71.5) in the validation set. Moreover, DCA showed that our proposed model resulted in higher net benefits within a defined range of risk thresholds. The cumulative incidence rate of SPMT differed among risk groups, classified according to nomogram risk scores.

CONCLUSION

The competing risk nomogram developed in this study exhibits high performance in predicting the occurrence of SPMT in patients with DTC. These findings may help clinicians identify patients at distinct levels of risk of SPMT and develop corresponding clinical management strategies.

TRβ Agonism Induces Tumor Suppression and Enhances Drug Efficacy in Anaplastic Thyroid Cancer in Female Mice

Thyroid hormone receptor beta (TRβ) is a recognized tumor suppressor in numerous solid cancers. The molecular signaling of TRβ has been elucidated in several cancer types through re-expression models. Remarkably, the potential impact of selective activation of endogenous TRβ on tumor progression remains largely unexplored. We used cell-based and in vivo assays to evaluate the effects of the TRβ agonist sobetirome (GC-1) on a particularly aggressive and dedifferentiated cancer, anaplastic thyroid cancer (ATC). Here we report that GC-1 reduced the tumorigenic phenotype, decreased cancer stem-like cell populations, and induced redifferentiation of the ATC cell lines with different mutational backgrounds. Of note, this selective activation of TRβ amplified the effects of therapeutic agents in blunting the aggressive cell phenotype and stem cell growth. In xenograft assays, GC-1 alone inhibited tumor growth and was as effective as the kinase inhibitor, sorafenib. These results indicate that selective activation of TRβ not only induces a tumor suppression program de novo but enhances the effectiveness of anticancer agents, revealing potential novel combination therapies for ATC and other aggressive solid tumors.

Cytoplasmic Localization of Thyroid Hormone Receptor (TR) Alpha and Nuclear Expression of Its Isoform TRα2 Determine Survival in Breast Cancer in Opposite Ways

The aim of this retrospective study was to assess the respective prognostic values of cytoplasmic and nuclear TRα, TRα1, and TRα2 expression in breast cancer (BC) tissue samples and correlate the results with clinico-pathological parameters. In 249 BC patients, the expression patterns of general TRα and the α1 and α2 isoforms were evaluated via immuno-histochemistry. Prognosis-determining aspects were calculated via univariate, as well as multivariate, analysis. Univariate Cox-regression analysis revealed no association between nuclear TRα expression and overall survival (OS) (p = 0.126), whereas cytoplasmic TRα expression was significantly correlated with a poor outcome for both OS (p = 0.034) and ten-year survival (p = 0.009). Strengthening these results, cytoplasmic TRα was found to be an independent marker of OS (p = 0.010) when adjusted to fit clinico-pathological parameters. Analyses of the TRα-subgroups revealed that TRα1 had no prognostic relevance, whereas nuclear TRα2 expression was positively associated with OS (p = 0.014), ten-year survival (p = 0.029), and DFS (p = 0.043). Additionally, nuclear TRα2 expression was found to be an independent positive prognosticator (p = 0.030) when adjusted to fit clinico-pathological parameters. Overall, our results support the hypothesis that subcellular localization of TRα and its isoforms plays an important role in the carcinogenesis and prognosis of breast cancer. Cytoplasmic TRα expression correlates with more aggressive disease progression, whereas nuclear TRα2 expression appears to be a protective factor. These data may help us to prioritize high-risk BC subgroups for possible targeted tumor therapy.

The Interplay between T Cells and Cancer: The Basis of Immunotherapy

Over the past decade, immunotherapy has emerged as one of the most promising approaches to cancer treatment. The use of immune checkpoint inhibitors has resulted in impressive and durable clinical responses in the treatment of various cancers. Additionally, immunotherapy utilizing chimeric antigen receptor (CAR)-engineered T cells has produced robust responses in blood cancers, and T cell receptor (TCR)-engineered T cells are showing promising results in the treatment of solid cancers. Despite these noteworthy advancements in cancer immunotherapy, numerous challenges remain. Some patient populations are unresponsive to immune checkpoint inhibitor therapy, and CAR T cell therapy has yet to show efficacy against solid cancers. In this review, we first discuss the significant role that T cells play in the body's defense against cancer. We then delve into the mechanisms behind the current challenges facing immunotherapy, starting with T cell exhaustion due to immune checkpoint upregulation and changes in the transcriptional and epigenetic landscapes of dysfunctional T cells. We then discuss cancer-cell-intrinsic characteristics, including molecular alterations in cancer cells and the immunosuppressive nature of the tumor microenvironment (TME), which collectively facilitate tumor cell proliferation, survival, metastasis, and immune evasion. Finally, we examine recent advancements in cancer immunotherapy, with a specific emphasis on T-cell-based treatments.

Identification of a Thyroid Hormone Binding Site in Hsp90 with Implications for Its Interaction with Thyroid Hormone Receptor Beta

While many proteins are known clients of heat shock protein 90 (Hsp90), it is unclear whether the transcription factor, thyroid hormone receptor beta (TRb), interacts with Hsp90 to control hormonal perception and signaling. Higher Hsp90 expression in mouse fibroblasts was elicited by the addition of triiodothyronine (T3). T3 bound to Hsp90 and enhanced adenosine triphosphate (ATP) binding of Hsp90 due to a specific binding site for T3, as identified by molecular docking experiments. The binding of TRb to Hsp90 was prevented by T3 or by the thyroid mimetic sobetirome. Purified recombinant TRb trapped Hsp90 from cell lysate or purified Hsp90 in pull-down experiments. The affinity of Hsp90 for TRb was 124 nM. Furthermore, T3 induced the release of bound TRb from Hsp90, which was shown by streptavidin-conjugated quantum dot (SAv-QD) masking assay. The data indicate that the T3 interaction with TRb and Hsp90 may be an amplifier of the cellular stress response by blocking Hsp90 activity.

Hormonal Crosstalk Between Thyroid and Breast Cancer

Differentiated thyroid cancer and breast cancer account for a significant portion of endocrine-related malignancies and predominately affect women. As hormonally responsive tissues, the breast and thyroid share endocrine signaling. Breast cells are responsive to thyroid hormone signaling and are affected by altered thyroid hormone levels. Thyroid cells are responsive to sex hormones, particularly estrogen, and undergo protumorigenic processes upon estrogen stimulation. Thyroid and sex hormones also display significant transcriptional crosstalk that influences oncogenesis and treatment sensitivity. Obesity-related adipocyte alterations-adipocyte estrogen production, inflammation, feeding hormone dysregulation, and metabolic syndromes-promote hormonal alterations in breast and thyroid tissues. Environmental toxicants disrupt endocrine systems, including breast and thyroid homeostasis, and influence pathologic processes in both organs through hormone mimetic action. In this brief review, we discuss the hormonal connections between the breast and thyroid and perspectives on hormonal therapies for breast and thyroid cancer. Future research efforts should acknowledge and further explore the hormonal crosstalk of these tissues in an effort to further understand the prevalence of thyroid and breast cancer in women and to identify potential therapeutic options.

Development of Histologically Verified Thyroid Diseases in Women Operated for Breast Cancer: A Review of the Literature and a Case Series

Background: The possible relationships between breast and thyroid diseases have been reported in the literature. The purpose of our study was to evaluate the occurrence of histologically verified thyroid pathologies in women who were diagnosed with breast cancer and, after mastectomy/quadrantectomy complemented by oncological treatment, were thyroidectomized based on their periodic thyroid evaluation. Patients and Methods: Our series consist of 31 women with a mean age of 62.9 ± 10.9 years (range, 45–81) treated for breast cancer (18 right-sided, 11 left-sided, and 2 bilateral), of whom 29 were thyroidectomized, since two women who developed Graves’ disease refused thyroidectomy. These 31 women belong to a cohort of 889 women who referred to the Breast Surgery Unit of our university hospital during the period January 2010 through December 2020. Results: The mean time interval between breast cancer and thyroid pathologies was 48.1 ± 23.4 months (range, 12–95). The final diagnosis at histopathology was infiltrating ductal breast carcinoma in 26 women (with 2/26 patients having bilateral carcinoma) and infiltrating lobular breast carcinoma in the other 5 women. Ten of the twenty-nine thyroidectomized women (34.5%) had a thyroid malignancy on histology: five papillary carcinomas, three papillary micro-carcinomas and two follicular carcinomas. Two of the five women with papillary carcinoma also had histological evidence of chronic lymphocytic thyroiditis/Hashimoto’s thyroiditis, which was also detected in another five women with benign thyroid diseases. Conclusions: We suggest that breast cancer survivors should be made aware of the possible increased risk of thyroid pathologies (including thyroid malignancy) so that they can undergo screening and follow-up.

Regulation of cancer stem cell activity by thyroid hormone receptor β

Increasing numbers of cancer stem cell markers have been recently identified. It is not known, however, whether a member of the nuclear receptor superfamily, thyroid hormone receptor β (TRβ), can function to regulate cancer stem cell (CSC) activity. Using anaplastic thyroid cancer cells (ATC) as a model, we highlight the role of TRβ in CSC activity. ATC is one of the most aggressive solid cancers in humans and is resistant to currently available therapeutics. Recent studies provide evidence that CSC activity underlies aggressiveness and therapeutic resistance of ATC. Here we show that TRβ inhibits CSC activity by suppressing tumor-sphere formation of human ATC cells and their tumor-initiating capacity. TRβ suppresses the expression of CSC regulators, including ALDH, KLF2, SOX2, b-catenin, and ABCG2, in ATC cell-induced xenograft tumors. Single-cell transcriptomic analysis shows that TRβ reduces CSC population in ATC-induced xenograft tumors. Analysis of The Cancer Genome Atlas (TCGA) database demonstrates that the inhibition of CSC capacity by TRβ contributes to favorable clinical outcomes in human cancer. Our studies show that TRβ is a newly identified transcription regulator that acts to suppress CSC activity and that TRβ could be considered as a molecular target for therapeutic intervention of ATC.

Thyroid Diseases and Breast Cancer

Epidemiological studies aimed at defining the association of thyroid diseases with extra-thyroidal malignancies (EM) have aroused considerable interest in the possibility of revealing common genetic and environmental factors underlying disease etiology and progression. Over the years, multiple lines of evidence indicated a significant relationship between thyroid carcinomas and other primary EM, especially breast cancer. For the latter, a prominent association was also found with benign thyroid diseases. In particular, a meta-analysis revealed an increased risk of breast cancer in patients with autoimmune thyroiditis, and our recent work demonstrated that the odds ratio (OR) for breast cancer was raised in both thyroid autoantibody-positive and -negative patients. However, the OR was significantly lower for thyroid autoantibody-positive patients compared to the negative ones. This is in agreement with findings showing that the development of thyroid autoimmunity in cancer patients receiving immunotherapy is associated with better outcome and supports clinical evidence that breast cancer patients with thyroid autoimmunity have longer disease-free interval and overall survival. These results seem to suggest that factors other than oncologic treatments may play a role in the initiation and progression of a second primary malignancy. The molecular links between thyroid autoimmunity and breast cancer remain, however, unidentified, and different hypotheses have been proposed. Here, we will review the epidemiological, clinical, and experimental data relating thyroid diseases and breast cancer, as well as the possible hormonal and molecular mechanisms underlying such associations.

Construction of a Pearson- and MIC-Based Co-expression Network to Identify Potential Cancer Genes

The weighted gene co-expression network analysis (WGCNA) method constructs co-expressed gene modules based on the linear similarity between paired gene expressions. Linear correlations are the main form of similarity between genes, however, nonlinear correlations still existed and had always been ignored. We proposed a modified network analysis method, WGCNA-P + M, which combines Pearson's correlation coefficient and the maximum information coefficient (MIC) as the similarity measures to assess the linear and nonlinear correlations between genes, respectively. Taking two real datasets, GSE44861 and liver hepatocellular carcinoma (TCGA-LIHC), as examples, we compared the gene modules constructed by WGCNA-P + M and WGCNA from four perspectives: the "Usefulness" score, GO enrichment analysis on genes in the gray module, prediction performance of the top hub gene, survival analysis and literature reports on different hub genes. The results showed that the modules obtained by WGCNA-P + M are more biological meaningful, the hub genes obtained from WGCNA-P + M have more potential cancer genes.

Co-occurrence of thyroid and breast cancer is associated with an increased oncogenic SNP burden

BACKGROUND

Epidemiological evidence suggests that synchronous or metachronous presentation of breast and thyroid cancers exceeds that predicted by chance alone. The following potential explanations have been hypothesized: common environmental or hormonal factors, oncogenic effect of the treatment for the first cancer, closer follow-up of cancer survivors, shared underlying genetic risk factors. While some cases were found to be related to monogenic disorders with autosomal inheritance, the genetic background of most cases of co-occurring breast and thyroid cancer is thought to be polygenic.

METHODS

In this retrospective case-control study we compared the genetic profile of patients with a history of breast cancer (n = 15) to patients with co-occurring breast and thyroid cancer (n = 19) using next generation sequencing of 112 hereditary cancer risk genes. Identified variants were categorized based on their known association with breast cancer and oncogenesis in general.

RESULTS

No difference between patients with breast and double cancers was observed in clinical and pathological characteristics or the number of neutral SNPs. The unweighted and weighted number of SNPs with an established or potential association with breast cancer was significantly lower in the group with breast cancer only (mean difference - 0.58, BCa 95% CI [- 1.09, - 0.06], p = 0.029, and mean difference - 0.36, BCa 95% CI [- 0.70, - 0.02], p = 0.039, respectively). The difference was also significant when we compared the number of SNPs with potential or known association with any malignancy (mean difference - 1.19, BCa 95% CI [- 2.27, - 0.11], p = 0.032 for unweighted, and mean difference - 0.73, BCa 95% CI [- 1.32, - 0.14], p = 0.017 for weighted scores).

CONCLUSION

Our findings are compatible with the hypothesis of genetic predisposition in the co-occurrence of breast and thyroid cancer. Further exploration of the underlying genetic mechanisms may help in the identification of patients with an elevated risk for a second cancer at the diagnosis of the first cancer.

The Prognostic Impact of Retinoid X Receptor and Thyroid Hormone Receptor alpha in Unifocal vs. Multifocal/Multicentric Breast Cancer

The aim of this study was to assess the prognostic value of the steroid hormone receptor expression, counting the retinoid X receptor (RXR) and thyroid hormone receptors (THRs), on the two different breast cancer (BC) entities: multifocal/multicentric versus unifocal. The overall and disease-free survival were considered as the prognosis determining aspects and analyzed by uni- and multi-variate analysis. Furthermore, histopathological grading and TNM staging (T = tumor size, N = lymph node involvement, M = distant metastasis) were examined in relation to RXR and THRs expression. A retrospective statistical analysis was carried out on survival-related events in a series of 319 sporadic BC patients treated at the Department of Gynecology and Obstetrics at the Ludwig-Maximillian's University in Munich between 2000 and 2002. The expression of RXR and THRs, including its two major isoforms THRα1 and THRα2, was analyzed by immunohistochemistry and showed to have a significant correlation for both BC entities in regard to survival analysis. Patients with multifocal/multicentric BC were exposed to a significantly worse disease-free survival (DFS) when expressing RXR. Patients with unifocal BC showed a significantly worse DFS when expressing THRα1. In contrast, a statistically significant positive association between THRα2 expression and enhanced DFS in multifocal/multicentric BC was shown. Especially the RXR expression in multifocal/multicentric BC was found to play a remarkably contradictory role for BC prognosis. The findings imply the need for a critical review of possible molecular therapies targeting steroid hormone receptors in BC treatment. Our results strengthen the need to further investigate the behavior of the nuclear receptor family, especially in relation to BC focality.

Cytoplasmic versus nuclear THR alpha expression determines survival of ovarian cancer patients

Purpose

Thyroid hormone receptors (THR) have manifold functions and are involved in the carcinogenesis of several tumor types. Within this study, we aimed to investigate the expression pattern (nuclear versus cytoplasmic) of the THR alpha and its impact on patients survival in ovarian cancer (OvCa).

Methods

The presence of the thyroid hormone receptors THRα, THRα1 and − 2 was investigated in 156 ovarian cancer samples using immunohistochemistry (IHC) using semi-quantitative immunoreactivity (IR) scores and correlated with clinical, pathological data, subtype of ovarian cancer, clinical data, staining of 20 already described OvCa marker proteins and overall survival (OS).

Results

Among all subtypes of OvCa, clear cell carcinomas showed the highest THRα expression. Furthermore, nuclear THRα was associated with a reduced survival in this subtype. However, nuclear expressed THRα1 turned out to be a positive prognosticator for all subtypes of OvCa patients. Nuclear THRα2 is a positive prognosticator for OvCa patients of the serous subtype. In contrast, cytoplasmic expression THRα2 was associated with a reduced OS in all subtypes of OvCa patients; while, cytoplasmic expression of THRα1 is associated with reduced OS in mucinous OvCa patients only. In addition, THRα expression correlates with gonadotropin receptors, steroid hormone receptors, TA-MUC1 and glycodelin.

Conclusion

Depending on nuclear or cytoplasmic expression, our study shows that THRα and its isoforms 1 and 2 provide different prognostic information for ovarian cancer patients. Further investigations should analyze if THRs may represent new endocrine targets for the treatment of ovarian cancer.

Electronic supplementary material

The online version of this article (10.1007/s00432-020-03241-7) contains supplementary material, which is available to authorized users.

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

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

An integrative bioinformatics analysis identified miR-375 as a candidate key regulator of malignant breast cancer

MicroRNAs (miRNAs) are key regulators that play important biological roles in carcinogenesis and are promising biomarkers for cancer diagnosis and therapy. hsa-miR-375-3p (miR-375) has been suggested to serve as a tumor suppressor or oncogene in various tumor types; however, its specific expression and potential regulatory role in malignant breast cancer remain unclear. In this study, the results from noncoding RNA microarray analysis indicated that the miR-375 expression level is significantly decreased in malignant basal-like breast cancer compared with luminal-like breast cancer. A total of 1895 co-downregulated and 1645 co-upregulated genes were identified in miR-375 mimic-transfected basal-like breast cancer cell lines. Predicted miR-375 targets were obtained from the online databases TargetScan and DIANA-microT-CDS. Combined KEGG enrichment analysis for coregulated genes and predicted miR-375 targets provided information and revealed differences in potential dynamic signaling pathways regulated by miR-375 and also indicated specific regulatory pathways, such as RNA transport and processing, in basal-like breast cancer. Additionally, gene expression microarray analysis accompanied by UALCAN analysis was performed to screen upregulated genes in the basal-like subtype. Four potential key genes, including LDHB, CPNE8, QKI, and EIF5A2, were identified as candidate target genes of miR-375. Therefore, the present study demonstrated that miR-375 may be a potential key regulator and provide a promising direction for diagnostic and therapeutic developments for malignant breast cancer.

Disruption of thyroid hormone regulated proteins and gene expression by polychlorinated biphenyls, polybrominated diphenyl ethers and new flame retardants in residents of an e-waste region

Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and new flame retardants (NFRs) are known thyroid hormone (TH) disruptors, but their disrupting mechanisms in humans are not completely understood. In this study, we aimed to explore the disrupting mechanisms of the aforementioned chemicals via examining TH-regulated proteins and gene expression in human serum. Adult participants from an e-waste dismantling (exposed group) and a control region (control group) in South China provided blood samples for the research. Some compounds of PCBs, PBDEs, and NFRs showed strong binding affinity to the thyroid-stimulating hormone (TSH), thyroglobulin, thyroxine-binding globulin (TBG), gene expression of TH receptor α (TRα) and β, and iodothyronine deiodinase I (ID1). The highly exposed individuals had lower levels of TBG, TSH, and expression of TRα, but higher expression of ID1 than those of the control group. The disruption of TH-regulated proteins and gene expression suggested the exertion of different and, at times, even contradictory effects on TH disruption. However, no statistically significant difference was found in the TH levels between the exposed and the control group, implying that the TH disruption induced by these chemicals depends on the combined influence of multiple mechanisms. Gene expression appears to be an effective approach for investigations of TH disruption and the potential health effects.

Gestational and Lactational Exposure to an Environmentally Relevant Mixture of Brominated Flame Retardants Downregulates Junctional Proteins, Thyroid Hormone Receptor α1 Expression, and the Proliferation-Apoptosis Balance in Mammary Glands Post Puberty

Mammary gland development requires hormonal regulation during puberty, pregnancy, and lactation. Brominated flame retardants (BFRs) are endocrine disruptors; they are added to consumer products to satisfy flammability standards. Previously, we showed that gestational and lactational exposure to an environmentally relevant mixture of BFRs disrupts proteins of the adherens junctions in rat dam mammary glands at weaning. Here, we hypothesize that perinatal exposure to the same BFR mixture also disrupts junctional proteins and signaling pathways controlling mammary gland development in pups. Dams were exposed through diet to a BFR mixture based on the substances in house dust; doses of the mixture used were 0, 0.06, 20, or 60 mg/kg/day. Dams were exposed continuously beginning prior to mating until pups' weaning; female offspring were euthanized on postnatal day (PND) 21, 46, and 208. The lowest dose of BFRs significantly downregulated adherens junction proteins, E-cadherin, and β-catenin, and the gap junction protein p-Cx43, as well as thyroid hormone receptor alpha 1 protein at PND 46. No effects were observed on estrogen or progesterone receptors. The low dose also resulted in a decrease in cleaved caspase-3, a downward trend in PARP levels, proteins involved in apoptosis, and an upward trend in proliferating cell nuclear antigen, a marker of proliferation. No effects were observed on ductal elongation or on the numbers of terminal end buds. Together, our results indicate that gestational and lactational exposure to an environmentally relevant mixture of BFRs disrupts cell-cell interactions, thyroid hormone homeostasis and the proliferation-apoptosis balance at PND 46, a critical stage for mammary gland development.

Serum concentration of thyroid hormones in abnormal and euthyroid ranges and breast cancer risk: A cohort study

The impact of variations in serum thyroid hormone concentration within the euthyroid range on breast cancer risk remains unclear. We investigated the effect of serum thyrotropin (TSH) and thyroid hormone concentration on breast cancer risk. This cohort study involved 62,546 Korean women, aged ≥40 years, who were free of breast cancer at baseline and underwent health examination with determination of free thyroxine (FT4) and TSH. A parametric proportional hazard model was used to estimate the adjusted hazard ratio (aHR) and 95% confidence interval (CI). During a median follow-up of 4.8 years (interquartile range: 2.8-7.3 years), 834 incident breast cancers were identified. Compared to normal FT4 level, abnormally high serum FT4 level was associated with an increased risk of incident breast cancer with a corresponding multivariable aHR (95% CI) of 1.98 (1.02-3.83). This association tended to be stronger in postmenopausal women than in premenopausal women. Within the euthyroid range, the highest TSH tertile was associated with a lower risk of breast cancer than the lowest TSH tertile with a corresponding aHR (95% CI) of 0.68 (0.55-0.84). In contrast, highest FT4 tertile was associated with a higher risk of breast cancer than the lowest FT4 tertile. Abnormally high FT4 as well as higher FT4 within the euthyroid range were positively associated with breast cancer risk, while higher TSH concentration within the euthyroid range was negatively associated with breast cancer risk. Our findings indicate that thyroid function within both the abnormal and euthyroid ranges may contribute to the development of breast cancer.

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.

The Antiarrhythmic Drug, Dronedarone, Demonstrates Cytotoxic Effects in Breast Cancer Independent of Thyroid Hormone Receptor Alpha 1 (THRα1) Antagonism

Previous research has suggested that thyroid hormone receptor alpha 1 (THRα1), a hormone responsive splice variant, may play a role in breast cancer progression. Whether THRα1 can be exploited for anti-cancer therapy is unknown. The antiproliferative and antitumor effects of dronedarone, an FDA-approved anti-arrhythmic drug which has been shown to antagonize THRα1, was evaluated in breast cancer cell lines in vitro and in vivo. The THRα1 splice variant and the entire receptor, THRα, were also independently targeted using siRNA to determine the effect of target knockdown in vitro. In our study, dronedarone demonstrates cytotoxic effects in vitro and in vivo in breast cancer cell lines at doses and concentrations that may be clinically relevant. However, knockdown of either THRα1 or THRα did not cause substantial anti-proliferative or cytotoxic effects in vitro, nor did it alter the sensitivity to dronedarone. Thus, we conclude that dronedarone’s cytotoxic effect in breast cancer cell lines are independent of THRα or THRα1 antagonism. Further, the depletion of THRα or THRα1 does not affect cell viability or proliferation. Characterizing the mechanism of dronedarone’s anti-tumor action may facilitate drug repurposing or the development of new anti-cancer agents.

The nuclear corepressor 1 and the thyroid hormone receptor β suppress breast tumor lymphangiogenesis

Vascular Endotelial Growth Factors C and D (VEGF-C and VEGF-D) are crucial regulators of lymphangiogenesis, a main event in the metastatic spread of breast cancer tumors. Although inhibition of lymphangiogenic gene expression might be a useful therapeutic strategy to restrict the progression of cancer, the factors involved in the transcriptional repression of these genes are still unknown. We have previously shown that Nuclear Receptor Corepressor 1 (NCoR) and the thyroid hormone receptor β1 (TRβ) inhibit tumor invasion. Here we show that these molecules repress VEGF-C and VEGF-D gene transcription in breast cancer cells, reducing lymphatic vessel density and sentinel lymph node invasion in tumor xenografts. The clinical significance of these results is stressed by the finding that NCoR and TRβ transcripts correlate negatively with those of the lymphangiogenic genes and the lymphatic vessel marker LYVE-1 in human breast tumors. Our results point to the use of NCoR and TRβ as potential biomarkers for diagnosis or prognosis in breast cancer and suggest that further studies of these molecules as potential targets for anti-lymphangiogenic therapy are warranted.

Analysis of Thyroid Tumorigenesis in Xenograft Mouse Model

Analysis of thyroid tumorigenesis in xenograft mouse model is important to study human thyroid cancer. Recent studies have made big strides toward understanding the molecular mechanisms by which thyroid hormone nuclear receptors (TR) act to maintain normal cellular functions in growth, differentiation, and development. Despite growing interest, the role of TR in oncogenesis remains to be fully elucidated. Two TR genes give rise to three major TR isoforms: TRα1, TRβ1, and TRβ2. These TR subtypes express in a tissue- and development-dependent manner. Research has been directed at understanding the mechanisms by which TR could mediate aberrant cellular signaling that contributes to oncogenesis, at dissecting possible distinct roles of TR isoforms in oncogenesis, and at the differential susceptibility of target tissues to the oncogenic actions of TR. This chapter gives a brief overview of the current undersatanding of known molecular oncogenic actions of TR. Here, we describe analysis of thyroid tumorigenesis used in interrogating the in vivo oncogenic actions of TR.

Thyroid peroxidase (TPO) expressed in thyroid and breast tissues shows similar antigenic properties

BACKGROUND

Thyroid peroxidase (TPO) is essential for physiological function of the thyroid gland. The high prevalence of thyroid peroxidase antibodies (TPOAbs) in patients with breast cancer and their protective role had previously been demonstrated, indicating a link between breast cancer and thyroid autoimmunity. Recently, TPO was shown to be present in breast cancer tissue samples but its antigenicity has not been analyzed.

METHODS

In this study, we investigated TPO expression levels in a series of fifty-six breast cancer samples paired with normal (peri-tumoral) tissue and its antigenic activity using a panel of well-characterized murine anti-human TPOAbs.

RESULTS

We have shown that TPO transcripts were present in both normal and cancer tissue samples, although the amounts in the latter were reduced. Additionally, we observed that TPO levels are lower in more advanced cancers. TPO protein expression was confirmed in all tissue samples, both normal and cancerous. We also found that the antigenicity of the immunodominant regions (IDRs) in breast TPO resembles that of thyroid TPO, which is crucial for effective interactions with human TPOAbs.

CONCLUSIONS

Expression of TPO in breast cancer together with its antigenic activity may have beneficial effects in TPOAb-positive breast cancer patients. However, further studies are needed to confirm the beneficial role of TPOAbs and to better understand the underlying mechanism.

Comparison of the seleno-transcriptome expression between human non-cancerous mammary epithelial cells and two human breast cancer cell lines

Breast cancer is the second most common cause of mortality in women; therefore, the identification of novel putative markers is required to improve its diagnosis and prognosis. Selenium is known to protect mammary epithelial cells from oxidative DNA damage, and to inhibit the initiation phase of carcinogenesis by stimulating DNA repair and apoptosis regulation. Consequently, the present study has focused attention on the selenoprotein family and their involvement in breast cancer. The present study performed a global analysis of the seleno-transcriptome expression in human breast cancer MCF-7 and MDA-MB231 cell lines compared with healthy breast MCF-10A cells using reverse transcription-quantitative polymerase chain reaction. The present data revealed the presence of differently expressed genes in MCF-7 and MDA-MB231 cells compared with MCF-10A cells: Four downregulated [glutathione peroxidase (GPX)1, GPX4, GPX5 and GPX7] and three upregulated (deiodinase iodothyronine, type II, GPX2 and GPX3) genes. Additionally, interactomic investigation were performed by the present study to evaluate the association between the downregulated and upregulated genes, and to identify putative HUB nodes, which represent the centers of association between the genes that are capable of direct control over the gene networks. Network analysis revealed that all differentially regulated genes, with the exception of selenoprotein T, are implicated in the same network that presents three HUB nodes interconnected to the selenoprotein mRNAs, including TP53, estrogen receptor 1 and catenin-β1 (CTNNB1). Overall, these data demonstrated for the first time, a profile of seleno-mRNAs specific for human breast cells, indicating that these genes alter their expression on the basis of the ER-positivity or negativity of breast cancer cells.

The Breast-Thyroid Cancer Link: A Systematic Review and Meta-analysis

Rates of thyroid cancer in women with a history of breast cancer are higher than expected. Similarly, rates of breast cancer in those with a history of thyroid cancer are increased. Explanations for these associations include detection bias, shared hormonal risk factors, treatment effect, and genetic susceptibility. With increasing numbers of breast and thyroid cancer survivors, clinicians should be particularly cognizant of this association. Here, we perform a systematic review and meta-analysis of the literature utilizing PubMed and Scopus search engines to identify all publications studying the incidence of breast cancer as a secondary malignancy following a diagnosis of thyroid cancer or thyroid cancer following a diagnosis of breast cancer. This demonstrated an increased risk of thyroid cancer as a secondary malignancy following breast cancer [OR = 1.55; 95% confidence interval (CI), 1.44-1.67] and an increased risk of breast cancer as a secondary malignancy following thyroid cancer (OR = 1.18; 95% CI, 1.09-1.26). There is a clear increase in the odds of developing either thyroid or breast cancer as a secondary malignancy after diagnosis with the other. Here, we review this association and current hypothesis as to the cause of this correlation.

T3/TRs axis in hepatocellular carcinoma: new concepts for an old pair

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide, and its burden is expected to further increase in the next years. Chronic inflammation, induced by multiple viruses or metabolic alterations, and epigenetic and genetic modifications, cooperate in cancer development via a combination of common and distinct aetiology-specific pathways. In spite of the advances of classical therapies, the prognosis of this neoplasm has not considerably improved over the past few years. The advent of targeted therapies and the approval of the systemic treatment of advanced HCC with the kinase inhibitor sorafenib have provided some hope for the future. However, the benefits obtained from this treatment are still disappointing, as it extends the median life expectancy of patients by only few months. It is thus mandatory to find alternative effective treatments. Although the role played by thyroid hormones (THs) and their nuclear receptors (TRs) in human cancer is still unclear, mounting evidence indicates that they behave as oncosuppressors in HCC. However, the molecular mechanisms by which they exert this effect and the consequence of their activation following ligand binding on HCC progression remain elusive. In this review, we re-evaluate the existing evidence of the role of TH/TRs in HCC development; we will also discuss how TR alterations could affect fundamental biological processes, such as hepatocyte proliferation and differentiation, and consequently HCC progression. Finally, we will discuss if and how TRs can be foreseen as therapeutic targets in HCC and whether selective TR modulation by TH analogues may hold promise for HCC treatment.

The Thyroid Hormone Inactivating Enzyme Type 3 Deiodinase is Present in Bactericidal Granules and the Cytoplasm of Human Neutrophils

Neutrophils are important effector cells of the innate immune system. Thyroid hormone (TH) is thought to play an important role in their function. Intracellular TH levels are regulated by the deiodinating enzymes. The TH-inactivating type 3 deiodinase (D3) is expressed in infiltrating murine neutrophils, and D3 knockout mice show impaired bacterial killing upon infection. This suggests that D3 plays an important role in the bacterial killing capacity of neutrophils. The mechanism behind this effect is unknown. We aimed to assess the presence of D3 in human neutrophils, and determine its subcellular localization using confocal and electron microscopy, because this could give important clues about its function in these cells. D3 appeared to be present in the cytoplasm and in myeloperoxidase containing azurophilic granules and as well as lactoferrin containing specific granules within human neutrophils. This subcellular localization did not change upon activation of the cells. D3 is observed intracellularly during neutrophil extracellular trap formation, followed by a reduction of D3 staining after release of the neutrophil extracellular traps into the extracellular space. At the transcriptional level, human neutrophils expressed additional essential elements of TH metabolism, including TH transporters and TH receptors. Here, we demonstrate the presence and subcellular location of D3 in human neutrophils for the first time and propose a model, in which D3 plays a role in the bacterial killing capacity of neutrophils either through generation of iodide for the myeloperoxidase system or through modulation of intracellular TH bioavailability.

Thyroid hormone receptor β1 suppresses proliferation and migration by inhibiting PI3K/Akt signaling in human colorectal cancer cells

Thyroid hormone receptor β1 (TRβ1) is a ligand‑dependent transcription factor that belongs to the superfamily of nuclear receptors. TRβ1 has been found to act as a tumor suppressor in many solid tumors including breast cancer and hepatocellular carcinoma, but its role in the progression of human colorectal cancer (CRC) remains unclear. In this study, microarray data analysis revealed that TRβ1 mRNA was downregulated in CRC tumors compared with that in the normal counterparts in both The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets. Using a CRC tissue microarray (TMA), we confirmed that the expression of TRβ1 was decreased in human CRC tumor tissues in contrast to normal colorectal mucosal tissues. Notably, the TRβ1 expression was strongly correlated with tumor size (p=0.045). Furthermore, we found that CRC cell proliferation and migration were significantly inhibited by TRβ1 overexpression in vitro. Mechanistic studies indicated that activated phosphorylated Akt was clearly suppressed by TRβ1 in the CRC tissues and cells. In conclusion, this study provides evidence that TRβ1 plays a critical role in the progression of CRC via the PI3K/Akt pathway, and the TRβ1 gene may represent a novel target for CRC therapeutics.

Risk factors for subsequent endocrine-related cancer in childhood cancer survivors

Long-term adverse health conditions, including secondary malignant neoplasms, are common in childhood cancer survivors. Although mortality attributable to secondary malignancies declined over the past decades, the risk for developing a solid secondary malignant neoplasm did not. Endocrine-related malignancies are among the most common secondary malignant neoplasms observed in childhood cancer survivors. In this systematic review, we describe risk factors for secondary malignant neoplasms of the breast and thyroid, since these are the most common secondary endocrine-related malignancies in childhood cancer survivors. Radiotherapy is the most important risk factor for secondary breast and thyroid cancer in childhood cancer survivors. Breast cancer risk is especially increased in survivors of Hodgkin lymphoma who received moderate- to high-dosed mantle field irradiation. Recent studies also demonstrated an increased risk after lower-dose irradiation in other radiation fields for other childhood cancer subtypes. Premature ovarian insufficiency may protect against radiation-induced breast cancer. Although evidence is weak, estrogen-progestin replacement therapy does not seem to be associated with an increased breast cancer risk in premature ovarian-insufficient childhood cancer survivors. Radiotherapy involving the thyroid gland increases the risk for secondary differentiated thyroid carcinoma, as well as benign thyroid nodules. Currently available studies on secondary malignant neoplasms in childhood cancer survivors are limited by short follow-up durations and assessed before treatment regimens. In addition, studies on risk-modifying effects of environmental and lifestyle factors are lacking. Risk-modifying effects of premature ovarian insufficiency and estrogen-progestin replacement therapy on radiation-induced breast cancer require further study.

Tumor suppressive actions of the nuclear receptor corepressor 1

Nuclear Receptor Corepressor 1 (NCoR) is an important transcriptional regulator that interacts with nuclear receptors and other transcription factors. Recent results have shown the presence of inactivating mutations or deletions of the NCoR gene in human tumors. NCoR has a strong tumor suppressor activity, inhibiting invasion, metastasis formation and tumor growth in xenograft mouse models. These changes are associated to transcriptional inhibition of genes linked to bad prognosis and increased metastasis in cancer patients. NCoR loss causes a long-term repression of NCoR gene transcription, suggesting that NCoR deficiency in the cancer cell could be propagated playing a role in tumor progression in the absence of NCoR gene mutations. The thyroid hormone receptor TRβ increases NCoR expression and this induction is essential in mediating the anti-metastatic and tumor suppressive actions of the receptor. Since metastasis is the main cause of cancer-related deaths, these results define NCoR as a potential target for cancer therapy.

Mutation analysis underlying the downregulation of the thyroid hormone receptor β1 gene in the Chinese breast cancer population

PURPOSE

There are a growing number of reports suggesting that the aberrant expression and mutation of the thyroid hormone receptor β1 (TRβ1) gene is associated with the development of human neoplasms. However, its exact role in the pathogenesis of breast cancer remains elusive. In the present study, we analyzed the mRNA expression and mutations of the TRβ1 gene in the Chinese breast cancer population.

METHODS

The expression of TRβ1 mRNA was examined by real-time quantitative reverse transcription polymerase chain reaction, and mutations in the TRβ1 gene in the hotspot region that spans exons 7-10 were analyzed by polymerase chain reaction single-strand conformation polymorphism and automated DNA sequencing.

RESULTS

TRβ1 mRNA expression was significantly reduced in all 105 breast cancer specimens examined. A total of 20 samples showed truncating mutations within the exons 7-10 of the TRβ1 gene, where eight cases harbored a frame shift mutation (five cases of c.850insA in exon 7 and three cases c.1028delA in exon 8), whereas missense mutations were observed in 12 breast cancer cases. The 20 cases with mutation in the TRβ1 gene showed a reduction in TRβ1 mRNA expression compared with that observed in matched normal tissues. The mutation was also correlated with menopausal stage and estrogen receptor status.

CONCLUSION

The findings of the present study suggest that the aberrant expression and mutations of the TRβ1 gene are associated with the development of breast cancer and that the mutations in the TRβ1 gene partly serve as the underlying mechanism for TRβ1 inactivation in the Chinese breast cancer population.

Mineralocorticoid receptor suppresses cancer progression and the Warburg effect by modulating the miR-338-3p-PKLR axis in hepatocellular carcinoma

Hormones and their corresponding receptors are vital in controlling metabolism under normal physiologic and pathologic conditions, but less is known about their roles in the metabolism of cancer. Using a small interfering RNA screening approach, we examined the effects of silencing 20 well-known hormone receptors on the Warburg effect, specifically by measuring the production of lactate in four established hepatocellular carcinoma (HCC) cell lines. We found that silencing a variety of hormone receptors had effects on the production of this metabolite. Unexpectedly silencing of mineralocorticoid receptor (MR) significantly increased lactate production in all these HCC cell lines. Subsequent in vitro and in vivo studies showed that gain- and loss-of-function of MR significantly influenced HCC cellular proliferation, cell cycle distribution, and apoptosis. Furthermore, mechanistic studies revealed that MR as a transcriptional factor directly regulated the expression of miR-338-3p, suppressing the Warburg effects of HCC cells by targeting a key enzyme of glycolysis: pyruvate kinase, liver and red blood cells. Moreover, MR expression was significantly down-regulated in 81% of HCC patient tissues, caused by both chromosome deletion and histone deacetylation. Low expression of MR in tumor tissues was associated with poor patient prognosis. The expression level of miR-338-3p was found to positively correlate with the expression of MR in HCC tissues and to inversely correlate with expression of the enzyme pyruvate kinase, liver and red blood cells.

CONCLUSION

MR affects HCC development by modulating the miR-338-3p/pyruvate kinase, liver and red blood cells axis with an ability to suppress the Warburg effect.

STUDY OF THE PREVALENCE OF AUTOIMMUNE THYROID DISEASE IN WOMEN WITH BREAST CANCER

OBJECTIVE

The aim of this study was to analyze the prevalence of thyroid disorders in patients with a positive biopsy for breast cancer prior to specific antitumor treatment.

METHODS

The frequency and pattern of thyroid disorders were evaluated in 112 patients with breast cancer (G1) and 125 control patients (G2) by analyzing serum thyroid-stimulating hormone (TSH), anti-thyroid peroxidase antibodies, and anti-thyroglobulin antibodies. In addition, the expression of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2) was assessed in the breast biopsies by immunohistochemistry.

RESULTS

The frequency of thyroid disorders, such as changes in TSH levels and/or the presence of thyroid antibodies, was not different between the 2 groups examined (30.4% in G1 versus 28.0% in G2) (P = .69). However, a family history of thyroid disease was more frequent in patients with breast cancer (50.5% in G1 versus 28.2% in G2) (P = .001). Regarding the clinical stage of breast cancer, there was no difference between women with autoimmune thyroiditis and those without thyroid dysfunction (P = .316). Similarly, there were no differences in hormone receptor (estrogen or progesterone) and HER2 expression between patients who tested positive and those who tested negative for anti-thyroid antibodies (P = .052 and P = .549, respectively).

CONCLUSION

The data obtained in this study did not reveal a higher frequency of autoimmune thyroid disease in patients with breast cancer compared to controls. A family history of thyroid disease was more common in those with breast cancer.

MicroRNA-10a is reduced in breast cancer and regulated in part through retinoic acid

Background

MicroRNAs (miRNAs) are short non-coding RNA molecules that play a critical role in mRNA cleavage and translational repression, and are known to be altered in many diseases including breast cancer. MicroRNA-10a (miR-10a) has been shown to be deregulated in various cancer types. The aim of this study was to investigate miR-10a expression in breast cancer and to further delineate the role of retinoids and thyroxine in regulation of miR-10a.

Methods

Following informed patient consent and ethical approval, tissue samples were obtained during surgery. miR-10a was quantified in malignant (n = 103), normal (n = 30) and fibroadenoma (n = 35) tissues by RQ-PCR. Gene expression of Retinoic Acid Receptor beta (RARβ) and Thyroid Hormone receptor alpha (THRα) was also quantified in the same patient samples (n = 168). The in vitro effects of all-trans Retinoic acid (ATRA) and L-Thyroxine (T₄) both individually and in combination, on miR-10a expression was investigated in breast cancer cell lines, T47D and SK-BR-3.

Results

The level of miR-10a expression was significantly decreased in tissues harvested from breast cancer patients (Mean (SEM) 2.1(0.07)) Log₁₀ Relative Quantity (RQ)) compared to both normal (3.0(0.16) Log₁₀ RQ, p < 0.001) and benign tissues (2.6(0.17) Log₁₀ RQ, p < 0.05). The levels of both RARβ and THRα gene expression were also found to be decreased in breast cancer patients compared to controls (p < 0.001). A significant positive correlation was determined between miR-10a and RARβ (r = 0.31, p < 0.001) and also with THRα (r = 0.32, p < 0.001). In vitro stimulation assays revealed miR-10a expression was increased in both T47D and SK-BR-3 cells following addition of ATRA (2 fold (0.7)). While T₄ alone did not stimulate miR-10a expression, the combination of T₄ and ATRA was found to have a positive synergistic effect.

Conclusion

The data presented supports a potential tumour suppressor role for miR-10a in breast cancer, and highlights retinoic acid as a positive regulator of the microRNA.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1374-y) contains supplementary material, which is available to authorized users.

Orphan nuclear receptors as drug targets for the treatment of prostate and breast cancers

Nuclear receptors (NRs), a family of 48 transcriptional factors, have been studied intensively for their roles in cancer development and progression. The presence of distinctive ligand binding sites capable of interacting with small molecules has made NRs attractive targets for developing cancer therapeutics. In particular, a number of drugs have been developed over the years to target human androgen- and estrogen receptors for the treatment of prostate cancer and breast cancer. In contrast, orphan nuclear receptors (ONRs), which in many cases lack known biological functions or ligands, are still largely under investigated. This review is a summary on ONRs that have been implicated in prostate and breast cancers, specifically retinoic acid-receptor-related orphan receptors (RORs), liver X receptors (LXRs), chicken ovalbumin upstream promoter transcription factors (COUP-TFs), estrogen related receptors (ERRs), nerve growth factor 1B-like receptors, and ‘‘dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1’’ (DAX1). Discovery and development of small molecules that can bind at various functional sites on these ONRs will help determine their biological functions. In addition, these molecules have the potential to act as prototypes for future drug development. Ultimately, the therapeutic value of targeting the ONRs may go well beyond prostate and breast cancers.

Association of thyroid diseases with primary extra-thyroidal malignancies in women: results of a cross-sectional study of 6,386 patients

We here analyzed the prevalence of extra-thyroidal malignancies (EM) in 6,386 female patients affected by different thyroid disease (TD). At first, an age-matched analysis of EM in all patients was performed. We then evaluated EM prevalence in four TD diagnostic categories: non-nodular TD (n = 2,159); solitary nodule (n = 905); multinodular TD (n = 2,871); differentiated thyroid cancers (n = 451). Finally, patients were grouped based on the absence (n = 3,820) or presence of anti-thyroglobulin (TgAb) and/or anti-thyroperoxidase (TPOAb) (n = 2,369), or anti-Thyroid Stmulating Hormone (TSH) receptor autoantibodies (n = 197). A total of 673 EM were recorded. EM prevalence in TD patients was higher compared to the general population (Odds Ratio, OR 3.21) and the most frequent EM was breast cancer (OR 3.94), followed by colorectal (OR 2.18), melanoma (OR 6.71), hematological (OR 8.57), uterus (OR 2.52), kidney (OR 3.40) and ovary (OR 2.62) neoplasms. Age-matched analysis demonstrated that the risk of EM was maximal at age 0-44 yr (OR 11.28), remaining lower, but significantly higher that in the general population, in the 45-59 and 60-74 year age range. Breast and hematological malignancies showed an increased OR in all TD, while other cancers associated with specific TD. An increased OR for melanoma, breast and hematological malignancies was observed in both TPOAb and/or TgAb autoantibody negative and positive patients, while colorectal, uterus, kidney and ovary cancers showed an increased OR only in thyroid autoantibody negative patients. In conclusions, women affected by both benign and malignant TD, especially at a younger age and in absence of thyroid autoimmunity, have an increased risk of developing primary EM, thus requiring a careful follow-up and surveillance.

microRNAs 424 and 503 are mediators of the anti-proliferative and anti-invasive action of the thyroid hormone receptor beta

The thyroid hormone receptors (TRs) mediate tumor suppressive effects in hepatocarcinoma and breast cancer cells. Here we show that incubation of hepatocarcinoma SK-hep1 cells expressing TRb with the thyroid hormone T3 induces transcription of the polycistronic message coding for microRNAs 424 and 503. TRb binds to the promoter region of these miRNAs and T3 induces an exchange of corepressors and coactivators inducing histone acetylation and transcriptional stimulation. We have validated cell cycle components as targets of these miRNAs. Overexpression of miR-424 mimicked the repressive effect of T3 on cell proliferation, growth in suspension, migration and invasion. Knockdown of miR-424 or miR-503 reduced the inhibitory effect of the hormone. T3 increased miR-424 and miR-503 in breast cancer cells expressing TRb, and this induction is also involved in the anti-invasive effects of the hormone. Furthermore, miR-424 or miR-503 depletion enhanced extravasation to the lungs of hepatocarcinoma cells injected in the tail vein of mice. The levels of these miRNAs were reduced in xenograft tumors formed in hypothyroid nude mice that are more invasive. Therefore, miR-424 or miR-503 mediate anti-proliferative and anti-invasive actions of TRb both in cultured cells and in vivo.

Thyroid hormone receptor α in breast cancer: prognostic and therapeutic implications

We determined the expression of two transcriptional variants of thyroid hormone receptor alpha (THRα1 and THRα2) in samples from a cohort of breast cancer patients and correlated expression levels with survival. 130 women who were diagnosed with invasive breast carcinoma between 2007 and 2008 were included. Representative sections of their tumours were analyzed in triplicate on a tissue microarray for expression of THRα1 and THRα2 by immunohistochemistry. The prognostic significance of THRα1 and THRα2 expression was assessed using Kaplan-Meier survival analyses, adjusted for known prognostic factors. Seventy-four percent of tumours had high expression of THRα1 (Allred score ≥6) and 40 % had high expression of THRα2. Expression of THRα2 correlated positively with ER expression (p < 0.001) and with PR expression (p < 0.001), but negatively with HER2 expression (p = 0.018). Patients with low THRα2 expression had inferior 5-year overall survival (75.3 %) compared to those with high expression (91.7 %; p = 0.06). In a multivariate model, high THRα2 expression was a significant and independent prognosticator of improved overall survival (HR = 0.84; 95 % CI 0.71-0.98). Many breast tumours express THRα2 at high levels and these patients experience improved survival. Thyroid hormone signalling may be important in a proportion of breast cancers and THRα2 expression may be a regulator of signalling in this pathway.

T3 levels in relation to prognostic factors in breast cancer: a population-based prospective cohort study

BACKGROUND

The issue of a potential association between thyroid conditions/hormones and breast cancer has been studied extensively during the last decades but the results have been inconclusive and almost no studies have investigated breast cancer aggressiveness. We have previously found a positive association between prospectively measured levels of triiodothyronine (T3) and breast cancer incidence as well as breast cancer mortality. We now investigated prediagnostic T3 levels in relation to specific prognostic factors in breast cancer.

METHODS

The Malmö Preventive Project is a population-based prospective cohort including 2185 women in whom T3 levels were measured at baseline. That is, total T3 levels were measured before a potential diagnosis of breast cancer. Mean follow-up was 23.3 years and 149 women in the study population were diagnosed with invasive breast cancer. Tumours were classified according to selected prognostic factors of breast cancer; i.e. grade, tumour size, lymph node metastasis, and hormonal receptor status. T3 was handled both as tertiles and as a continuous variable. A Cox's proportional hazards analysis yielded hazard ratios with 95% confidence intervals. All analyses were also restricted to postmenopausal women.

RESULTS

Overall there was a statistically significant association between T3 and "all" breast cancers. The adjusted Hazard Ratio (HR) in the third tertile, as compared to the first, was (1.61:1.07-2.43). There was a statistically significant positive association between the third T3 tertile and large tumours, i.e. > 20 mm, (3.17:1.20-8.36) and the occurrence of lymph node metastases, (4.53:1.60-12.83). Other prognostic factors positively associated with T3 were negative oestrogen receptor (ER) status, (3.52:1.32-9.41) and negative progesterone receptor (PGR) status, (3.52:1.42-8.75). The analyses of T3 as a continuous variable and analysis restricted to postmenopausal women, confirmed the results but also showed an association with smaller tumours and in postmenopausal women a contemporary association with negative lymph nodes.

CONCLUSIONS

This prospective study of serum T3 levels in relation to breast cancer aggressiveness is the first of its kind. We found statistically significant positive associations between higher prediagnostic T3 levels and larger tumours, occurrence of lymph node metastases, and negative ER and PGR status.

Distinct nuclear receptor expression in stroma adjacent to breast tumors

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.

Inhibition of tumorigenesis by the thyroid hormone receptor β in xenograft models

BACKGROUND

Previous studies showed a close association between several types of human cancers and somatic mutations of thyroid hormone receptor β (TRβ) and reduced expression of TRβ due to epigenetic inactivation and/or deletion of the THRB gene. These observations suggest that TRβ could act as a tumor suppressor in carcinogenesis. However, the mechanisms by which TRβ could function to inhibit tumorigenesis are less well understood.

METHODS

We used the human follicular thyroid cancer cell lines (FTC-133 and FTC-236 cells) to elucidate how functional expression of the THRB gene could affect tumorigenesis. We stably expressed the THRB gene in FTC cells and evaluated the effects of the expressed TRβ on cancer cell proliferation, migration, and tumor growth in cell-based studies and xenograft models.

RESULTS

Expression of TRβ in FTC-133 cells, as compared with control FTC cells without TRβ, reduced cancer cell proliferation and impeded migration of tumor cells through inhibition of the AKT-mTOR-p70 S6K pathway. TRβ expression in FTC-133 and FTC-236 led to less tumor growth in xenograft models. Importantly, new vessel formation was significantly suppressed in tumors induced by FTC cells expressing TRβ compared with control FTC cells without TRβ. The decrease in vessel formation was mediated by the downregulation of vascular endothelial growth factor in FTC cells expressing TRβ.

CONCLUSIONS

These findings indicate that TRβ acts as a tumor suppressor through downregulation of the AKT-mTOR-p70 S6K pathway and decreased vascular endothelial growth factor expression in FTC cells. The present results raise the possibility that TRβ could be considered as a potential therapeutic target for thyroid cancer.

Down-regulation of thyroid hormone receptor β1 gene expression in gastric cancer involves promoter methylation

Hypermethylation has been shown in the promoter region of the thyroid hormone receptor β1 (TRβ1) gene in several human tumors. However, its role in gastric cancer formation is still unclear. In the study, we analyzed mRNA expression of TRβ1 gene using real-time quantitative PCR (qPCR). A quantitative methylation-specific PCR (Q-MSP) assay was used to determine the methylation status of the TRβ1 gene promoter region in 46 pair-matched gastric neoplastic and adjacent non-neoplastic tissues. The results showed that TRβ1 mRNA expression was significantly reduced in gastric cancer specimens. The methylation of promoter of TRβ1 gene in gastric cancer tissues was significantly higher than in adjacent normal tissues. Promoter hypermethylation of the TRβ1 gene correlated with tumor infiltration, lymph node metastasis, and distant metastasis, but it was not associated with other clinicopathological characteristics. We treated gastric cancer cell lines MKN-45, MKN-28, SGC-7901, NCI-N87, and SNU-1 with 5-Aza-2-deoxycytidine (5-Aza-dC). The results showed the expression of TRβ1 mRNA was increased in MKN-45, MKN-28, SGC-7901, but not increased in NCI-N87 and SNU-1. These results suggest that the TRβ1 gene plays important roles in the development of gastric cancer partially through epigenetic mechanisms.

Genetic features of thyroid hormone receptors

Thyroid hormone receptors (TR) are prototypes of nuclear transcription factors that regulate the expression of target genes. These receptors play an important role in many physiological processes. Moreover, a dysfunction of these proteins is often implicated in several human diseases and malignancies. Here we report genetic variations and alterations of the TRs that have been described in the literature as well as their potential role in the development of some human diseases including cancers. The functional effects of some mutations and polymorphisms in TRs on disease susceptibility, especially on cancer risk, are now established. Therefore, further investigations are needed in order to use these receptors as therapeutic targets or as biological markers to decide on appropriate forms of treatment.

Thyroid hormone receptors and cancer

BACKGROUND

Thyroid hormone receptors (TRs) are ligand-dependent transcription factors that mediate the actions of the thyroid hormone (T3) in development, growth, and differentiation. The THRA and THRB genes encode several TR isoforms that express in a tissue- and development-dependent manner. In the past decades, a significant advance has been made in the understanding of TR actions in maintaining normal cellular functions. However, the roles of TRs in human cancer are less well understood. The reduced expression of TRs because of hypermethylation, or deletion of TR genes found in human cancers suggests that TRs could function as tumor suppressors. A close association of somatic mutations of TRs with human cancers further supports the notion that the loss of normal functions of TR could lead to uncontrolled growth and loss of cell differentiation.

SCOPE OF REVIEW

In line with the findings from association studies in human cancers, mice deficient in total functional TRs (Thra1(-/-)Thrb(-/-) mice) or with a targeted homozygous mutation of the Thrb gene (denoted PV; Thrb(PV/PV) mice) spontaneously develop metastatic thyroid carcinoma. This review will examine the evidence learned from these genetically engineered mice that provided strong evidence to support the critical role of TRs in human cancer.

MAJOR CONCLUSIONS

Loss of normal functions of TR by deletion or by mutations could contribute to cancer development, progression and metastasis.

GENERAL SIGNIFICANCE

Novel mechanistic insights are revealed in how aberrant TR activities lead to carcinogenesis. Mouse models of thyroid cancer provide opportunities to identify molecular targets as potential treatment modalities. This article is part of a Special Issue entitled Thyroid hormone signalling.

Thyroid hormone actions in liver cancer

The thyroid hormone 3,3',5-triiodo-L-thyronine (T3) mediates several physiological processes, including embryonic development, cellular differentiation, metabolism, and the regulation of cell proliferation. Thyroid hormone receptors (TRs) generally act as heterodimers with the retinoid X receptor (RXR) to regulate target genes. In addition to their developmental and metabolic functions, TRs have been shown to play a tumor suppressor role, suggesting that their aberrant expression can lead to tumor transformation. Conversely, recent reports have shown an association between overexpression of wild-type TRs and tumor metastasis. Signaling crosstalk between T3/TR and other pathways or specific TR coregulators appear to affect tumor development. Since TR actions are complex as well as cell context-, tissue- and time-specific, aberrant expression of the various TR isoforms has different effects during diverse tumorigenesis. Therefore, elucidation of the T3/TR signaling mechanisms in cancers should facilitate the identification of novel therapeutic targets. This review provides a summary of recent studies focusing on the role of TRs in hepatocellular carcinomas (HCCs).

Biological significance of a thyroid hormone-regulated secretome

The thyroid hormone, 3,3,5-triiodo-L-thyronine (T3), modulates several physiological processes, including cellular growth, differentiation, metabolism and proliferation, via interactions with thyroid hormone response elements (TREs) in the regulatory regions of target genes. Several intracellular and extracellular protein candidates are regulated by T3. Moreover, T3-regulated secreted proteins participate in physiological processes or cellular transformation. T3 has been employed as a marker in several disorders, such as cardiovascular disorder in chronic kidney disease, as well as diseases of the liver, immune system, endocrine hormone metabolism and coronary artery. Our group subsequently showed that T3 regulates several tumor-related secretory proteins, leading to cancer progression via alterations in extracellular matrix proteases and tumor-associated signaling pathways in hepatocellular carcinomas. Therefore, elucidation of T3/thyroid hormone receptor-regulated secretory proteins and their underlying mechanisms in cancers should facilitate the identification of novel therapeutic targets. This review provides a detailed summary on the known secretory proteins regulated by T3 and their physiological significance. This article is part of a Special Issue entitled: An Updated Secretome.