FOXE1 association with differentiated thyroid cancer and its progression

Identification of Germline FOXE1 and Somatic MAPK Pathway Gene Alterations in Patients with Malignant Struma Ovarii, Cleft Palate and Thyroid Cancer

Germline variants in the FOXE1 transcription factor have been associated with thyroid ectopy, cleft palate (CP) and thyroid cancer (TC). Here, we aimed to clarify the role of FOXE1 in Portuguese families (F1 and F2) with members diagnosed with malignant struma ovarii (MSO), an ovarian teratoma with ectopic malignant thyroid tissue, papillary TC (PTC) and CP. Two rare germline heterozygous variants in the FOXE1 promoter were identified: F1) c.-522G>C, in the proband (MSO) and her mother (asymptomatic); F2) c.9C>T, in the proband (PTC), her sister and her mother (CP). Functional studies using rat normal thyroid (PCCL3) and human PTC (TPC-1) cells revealed that c.9C>T decreased FOXE1 promoter transcriptional activity in both cell models, while c.-522G>C led to opposing activities in the two models, when compared to the wild type. Immunohistochemistry and RT-qPCR analyses of patients' thyroid tumours revealed lower FOXE1 expression compared to adjacent normal and hyperplastic thyroid tissues. The patient with MSO also harboured a novel germline AXIN1 variant, presenting a loss of heterozygosity in its benign and malignant teratoma tissues and observable β-catenin cytoplasmic accumulation. The sequencing of the F1 (MSO) and F2 (PTC) probands' tumours unveiled somatic BRAF and HRAS variants, respectively. Germline FOXE1 and AXIN1 variants might have a role in thyroid ectopy and cleft palate, which, together with MAPK pathway activation, may contribute to tumours' malignant transformation.

The high expression of FOXE1 in colorectal cancer predicts a promising prognosis: a retrospective study

Purpose Forkhead box (FOX) family proteins regulate transcription and DNA repair and are involved in cell growth, differentiation, embryogenesis, and lifespan. The transcription factor FOXE1 is a member of the FOX family. The relationship between the expression level of FOXE1 and colorectal cancer (CRC) prognosis remains controversial. It is vital to verify the relationship between FOXE1 expression and the prognosis of patients with CRC. Methods We constructed a tissue microarray containing 879 primary colorectal cancer tissues and 203 normal mucosa samples. The tumor and normal mucosa tissues were stained with FOXE1 by immunohistochemistry, and the staining results were divided into two groups: high expression group and low expression group. Chi-square test was performed for the classification variable of the difference between FOXE1 expression levels and clinicopathological parameters. The survival curve was calculated according to the Kaplan-Meier method and the logarithmic rank test. The Cox proportional risk regression model was used for multivariate analysis of prognostic factors in patients with CRC.Results The expression level of FOXE1 in colorectal cancer was higher than that in the normal mucosa adjacent to cancer, although the difference was not significant. However, the expression of FOXE1 was correlated with tumor size, T stage, N stage, M stage, and pTNM stage. Univariate and multivariate analyses suggested that FOXE1 could be used as an independent prognostic factor in patients with CRC. Conclusions FOXE1 may be a potential independent prognostic factor for colorectal cancer patients.

The Role of Genetic Polymorphisms in Differentiated Thyroid Cancer: A 2023 Update

Thyroid cancer is the most common endocrine malignancy, with an increasing trend in the past decades. It has a variety of different histological subtypes, the most frequent one being differentiated thyroid cancer, which refers to papillary carcinoma, the most common histological type, followed by follicular carcinoma. Associations between genetic polymorphisms and thyroid cancer have been investigated over the years and are an intriguing topic for the scientific world. To date, the results of associations of single nucleotide polymorphisms, the most common genetic variations in the genome, with thyroid cancer have been inconsistent, but many promising results could potentially influence future research toward developing new targeted therapies and new prognostic biomarkers, thus consolidating a more personalized management for these patients. This review focuses on emphasizing the existing literature data regarding genetic polymorphisms investigated for their potential association with differentiated thyroid cancer and highlights the opportunity of using genetic variations as biomarkers of diagnosis and prognosis for thyroid cancer patients.

Adipocyte signaling affects thyroid-specific gene expression via down-regulation of TTF-2/FOXE1

Obesity affects thyroid gland function. Hypothyroidism, thyroid nodules, goiter, and thyroid cancer are more frequent in patients with higher BMI values. Although these data are supported by many clinical and epidemiological studies, our knowledge is very scarce at the molecular level. In this study, we present the first experimental evidence that adipocyte signaling downregulates the expression of thyroid-specific transcription factor 2 (TTF-2/FoxE1). It plays a crucial role in thyroid development and thyroid homeostasis and it is strictly connected to thyroid cancer as well. We provide in vivo and in vitro evidence that inhibition of TTF-2/FoxE1 gene expression is mediated by adipocyte signaling.

Foxe1 Deletion in the Adult Mouse Is Associated With Increased Thyroidal Mast Cells and Hypothyroidism

CONTEXT

Foxe1 is a key thyroid developmental transcription factor. Germline deletion results in athyreosis and congenital hypothyroidism. Some data suggest an ongoing role for maintaining thyroid differentiation.

OBJECTIVE

We created a mouse model to directly examine the role of Foxe1 in the adult thyroid.

METHODS

A model of tamoxifen-inducible Cre-mediated ubiquitous deletion of Foxe1 was generated in mice of C57BL/6J background (Foxe1flox/flox/Cre-TAM). Tamoxifen or vehicle was administered to Foxe1flox/flox/Cre mice aged 6-8 weeks. Blood was collected at 4, 12, and 20 weeks, and tissues after 12 or 20 weeks for molecular and histological analyses. Plasma total thyroxine (T4), triiodothyronine, and thyrotropin (TSH) were measured. Transcriptomics was performed using microarray or RNA-seq and validated by reverse transcription quantitative polymerase chain reaction.

RESULTS

Foxe1 was decreased by approximately 80% in Foxe1flox/flox/Cre-TAM mice and confirmed by immunohistochemistry. Foxe1 deletion was associated with abnormal follicular architecture and smaller follicle size at 12 and 20 weeks. Plasma TSH was elevated in Foxe1flox/flox/Cre-TAM mice as early as 4 weeks and T4 was lower in pooled samples from 12 and 20 weeks. Foxe1 deletion was also associated with an increase in thyroidal mast cells. Transcriptomic analyses found decreased Tpo and Tg and upregulated mast cell markers Mcpt4 and Ctsg in Foxe1flox/flox/Cre-TAM mice.

CONCLUSION

Foxe1 deletion in adult mice was associated with disruption in thyroid follicular architecture accompanied by biochemical hypothyroidism, confirming its role in maintenance of thyroid differentiation. An unanticipated finding was an increase in thyroidal mast cells. These data suggest a possible explanation for previous human genetic studies associating alleles in/near FOXE1 with hypothyroidism and/or autoimmune thyroiditis.

Regulation of Wnt Signaling by FOX Transcription Factors in Cancer

Simple Summary

Cancer is caused by a breakdown of cell-to-cell communication, which results in the unrestricted expansion of cells within a tissue. In many cases, tumor growth is maintained by the continuous activation of cell signaling programs that normally drive embryonic development and wound repair. In this review article, I discuss how one of the largest human protein families, namely FOX proteins, controls the activity of the Wnt pathway, a major regulatory signaling cascade in developing organisms and adult stem cells. Evidence suggests that there is considerable crosstalk between FOX proteins and the Wnt pathway, which contributes to cancer initiation and progression. A better understanding of FOX biology may therefore lead to the development of new targeted treatments for many types of cancer.

Abstract

Aberrant activation of the oncogenic Wnt signaling pathway is a hallmark of numerous types of cancer. However, in many cases, it is unclear how a chronically high Wnt signaling tone is maintained in the absence of activating pathway mutations. Forkhead box (FOX) family transcription factors are key regulators of embryonic development and tissue homeostasis, and there is mounting evidence that they act in part by fine-tuning the Wnt signaling output in a tissue-specific and context-dependent manner. Here, I review the diverse ways in which FOX transcription factors interact with the Wnt pathway, and how the ectopic reactivation of FOX proteins may affect Wnt signaling activity in various types of cancer. Many FOX transcription factors are partially functionally redundant and exhibit a highly restricted expression pattern, especially in adults. Thus, precision targeting of individual FOX proteins may lead to safe treatment options for Wnt-dependent cancers.

Diet as a possible influencing factor in thyroid cancer incidence: the point of view of the nutritionist

The incidence of differentiated thyroid cancer has increased in the last decades all over the world. Different environmental factors are possible perpetrators of this exponential growth. Nutritional factors are among the main environmental factors studied for thyroid cancer in recent years. This review aims to overview the main dietary factors involved in thyroid cancer risk, providing specific nutrition recommendations from the endocrinological Nutritionist point of view. Among the single food, fish and shellfish are the primary natural source of iodine, selenium and vitamin D in the human diet. These nutrients are essential for the synthesis of thyroid hormones; however, their consumption is not consistently related to thyroid cancer risk. The high intake of fruit and vegetables, probably due to their vitamin and antioxidant content, shows a weak inverse association with thyroid cancer risk. Alcohol, meat, or other food groups/nutrients showed no significant effect on thyroid cancer. In conclusion, to date, no definite association among dietary factors, specific dietary patterns, and thyroid cancer, and its clinical severity and aggressiveness have been found. However, it is essential to underline that in the future, prospective studies should be carried out to precisely evaluate the qualitative and quantitative intake of nutrients by patients to establish with more confidence a potential correlation between food intake and the occurrence and development of thyroid cancer.

Identifying Thyroid Carcinoma-Related Genes by Integrating GWAS and eQTL Data

Thyroid carcinoma (TC) is the most common endocrine malignancy. The incidence rate of thyroid cancer has increased rapidly in recent years. The occurrence and development of thyroid cancers are highly related to the massive genetic and epigenetic changes. Therefore, it is essential to explore the mechanism of thyroid cancer pathogenesis. Genome-Wide Association Studies (GWAS) have been widely used in various diseases. Researchers have found multiple single nucleotide polymorphisms (SNPs) are significantly related to TC. However, the biological mechanism of these SNPs is still unknown. In this paper, we used one GWAS dataset and two eQTL datasets, and integrated GWAS with expression quantitative trait loci (eQTL) in both thyroid and blood to explore the mechanism of mutations and causal genes of thyroid cancer. Finally, we found rs1912998 regulates the expression of IGFALS (P = 1.70E-06) and HAGH (P = 5.08E-07) in thyroid, which is significantly related to thyroid cancer. In addition, KEGG shows that these genes participate in multiple thyroid cancer-related pathways.

FOXE1 Gene Dosage Affects Thyroid Cancer Histology and Differentiation In Vivo

The transcription factor Forkhead box E1 (FOXE1) is a key player in thyroid development and function and has been identified by genome-wide association studies as a susceptibility gene for papillary thyroid cancer. Several cancer-associated polymorphisms fall into gene regulatory regions and are likely to affect FOXE1 expression levels. However, the possibility that changes in FOXE1 expression modulate thyroid cancer development has not been investigated. Here, we describe the effects of FOXE1 gene dosage reduction on cancer phenotype in vivo. Mice heterozygous for FOXE1 null allele (FOXE1^+/−) were crossed with a BRAF^V600E-inducible cancer model to develop thyroid cancer in either a FOXE1^+/+ or FOXE1^+/− genetic background. In FOXE1^+/+ mice, cancer histological features are quite similar to that of human high-grade papillary thyroid carcinomas, while cancers developed with reduced FOXE1 gene dosage maintain morphological features resembling less malignant thyroid cancers, showing reduced proliferation index and increased apoptosis as well. Such cancers, however, appear severely undifferentiated, indicating that FOXE1 levels affect thyroid differentiation during neoplastic transformation. These results show that FOXE1 dosage exerts pleiotropic effects on thyroid cancer phenotype by affecting histology and regulating key markers of tumor differentiation and progression, thus suggesting the possibility that FOXE1 could behave as lineage-specific oncogene in follicular cell-derived thyroid cancer.

The Contribution of Genetic Variants to the Risk of Papillary Thyroid Carcinoma in the Kazakh Population: Study of Common Single Nucleotide Polymorphisms and Their Clinicopathological Correlations

OBJECTIVE

Risk for developing papillary thyroid carcinoma (PTC), the most common endocrine malignancy, is thought to be mediated by lifestyle, environmental exposures and genetic factors. Recent progress in the genome-wide association studies of thyroid cancer leads to the identification of several genetic variants conferring risk to this malignancy across different ethnicities. We set out to elucidate the impact of selected single nucleotide polymorphisms (SNPs) on PTC risk and to evaluate clinicopathological correlations of these genetic variants in the Kazakh population for the first time.

METHODS

Eight SNPs were genotyped in 485 patients with PTC and 1,008 healthy control Kazakh subjects. The association analysis and multivariable modeling of PTC risk by the genetic factors, supplemented with rigorous statistical validation, were performed.

RESULT

Five of the eight SNPs: rs965513 (FOXE1/PTCSC2, P = 1.3E-16), rs1867277 (FOXE1 5'UTR, P = 7.5E-06), rs2439302 (NRG1 intron 1, P = 4.0E-05), rs944289 (PTCSC3/NKX2-1, P = 4.5E-06) and rs10136427 (BATF upstream, P = 9.8E-03) were significantly associated with PTC. rs966423 (DIRC3, P = 0.07) showed a suggestive association. rs7267944 (DHX35) was associated with PTC risk in males (P = 0.02), rs1867277 (FOXE1) conferred the higher risk in subjects older than 55 years (P = 7.0E-05), and rs6983267 (POU5F1B/CCAT2) was associated with pT3-T4 tumors (P = 0.01). The contribution of genetic component (unidirectional independent effects of rs965513, rs944289, rs2439302 and rs10136427 adjusted for age and sex) to PTC risk in the analyzed series was estimated to be 30-40%.

CONCLUSION

Genetic factors analyzed in the present work display significant association signals with PTC either on the whole group analysis or in particular clinicopathological groups and account for about one-third of the risk for PTC in the Kazakh population.

Influencers on Thyroid Cancer Onset: Molecular Genetic Basis

Thyroid cancer, a cancerous tumor or growth located within the thyroid gland, is the most common endocrine cancer. It is one of the few cancers whereby incidence rates have increased in recent years. It occurs in all age groups, from children through to seniors. Most studies are focused on dissecting its genetic basis, since our current knowledge of the genetic background of the different forms of thyroid cancer is far from complete, which poses a challenge for diagnosis and prognosis of the disease. In this review, we describe prevailing advances and update our understanding of the molecular genetics of thyroid cancer, focusing on the main genes related with the pathology, including the different noncoding RNAs associated with the disease.

FOXE1 inhibits cell proliferation, migration and invasion of papillary thyroid cancer by regulating PDGFA

PURPOSE

Forkhead box E1 (FOXE1) plays an important role in the development, proliferation and differentiation of thyroid cells. However, the biological functions of FOXE1 in papillary thyroid cancer (PTC) remain unclear.

MATERIALS AND METHODS

In this study, the level of FOXE1 expression was examined in human PTC tissues and cells. Then, the high expression of FOXE1 was specifically silenced by RNA interference in vitro. Subsequently, FOXE1-shRNA was transfected into PTC cells (TPC-1 and K1). The effects on cell proliferation, migration and invasion were evaluated. In addition, FOXE1 targets were screened by cDNA microarray assays. The correlation between the expression of target gene platelet-derived growth factor A (PDGFA) and clinicopathological features of PTC patients was analysed.

RESULTS

FOXE1 is highly expressed in PTC tissues and PTC cell lines. The silencing of FOXE1 significantly promotes PTC cell proliferation, migration and invasion in vitro. The cDNA microarray analyses show that PDGFA is a critical downstream target gene of FOXE1 in PTC cells. It was also observed that PDGFA is negatively regulated by FOXE1 in PTC. The clinical data indicate that the low expression level of PDGFA is correlated with the small size of PTC.

CONCLUSION

Collectively, the results indicate for the first time that high expression of FOXE1 may function as a tumour suppressor in the early stage of PTC and restrain the proliferation, migration and invasion of PTC by negatively regulating PDGFA expression. Thus, FOXE1 could serve as a prognostic biomarker for PTC.

A Case of Papillary Thyroid Carcinoma and Kostmann Syndrome: A Genomic Theranostic Approach for Comprehensive Treatment

BACKGROUND Theranostics is a combined diagnostic and treatment approach to individualized patient care. Kostmann syndrome, or severe congenital neutropenia, is an autosomal recessive disease that affects the production of neutrophils. Papillary thyroid carcinoma (PTC) is the most common type of thyroid malignancy associated with gene alterations, including in the mitogen-activated protein kinase (MAPK) signaling pathway gene. Translocation of the ETS variant 6/neurotrophic receptor tyrosine kinase 3 (ETV6/NTRK3) gene has been implicated in radiation-induced and pediatric forms of thyroid carcinoma but has rarely been described in sporadic PTC. This report is of a case of PTC in a patient with Kostmann syndrome associated with ETV6/NTRK3 gene translocation. CASE REPORT A 32-year-old woman with a history of Kostmann syndrome, acute myeloid leukemia (AML), and chronic graft versus host disease (GVHD) was diagnosed with PTC with cervical lymph node metastases and soft tissue invasion following total thyroidectomy and bilateral modified radical neck dissection. Her postoperative radioactive iodine (RAI) scan confirmed lymph node metastasis. Gene expression studies identified increased expression of iodine-handling genes and ETV6/NTRK3 gene fusion. Because of the bone marrow compromise due to Kostmann syndrome and AML, a careful genomic and molecular analysis was performed to guide therapy. CONCLUSIONS This is the first reported case of the association between PTC, Kostmann syndrome, and ETV6/NTRK3 gene translocation in which multimodality treatment planning was optimized by genomic profiling.

Investigation of candidate genes of non-syndromic cleft lip with or without cleft palate, using both case-control and family-based association studies

OBJECTIVE

Non-syndromic cleft of the lip and/or palate (NSCL/P) is one of the most common polygenic diseases. In this study, both case-control and family-based association study were used to confirm whether the Single Nucleotide Polymorphisms (SNPs) were associated with NSCL/P.

METHODS

A total of 37 nuclear families and 189 controls were recruited, whose blood DNA was extracted and subjected to genotyping of SNPs of 27 candidate genes by polymerase chain reaction-improved multiple ligase detection reaction technology (PCR-iMLDR). Case-control statistical analysis was performed using the SPSS 19.0. Haplotype Relative Risk (HRR), transmission disequilibrium test (TDT), and Family-Based Association Test (FBAT) were used to test for over-transmission of the target alleles in case-parent trios. The gene-gene interactions on NSCL/P were analyzed by Unphased-3.1.4.

RESULTS

In case-control statistical analysis, only C14orf49 chr14_95932477 had statistically significant on genotype model (P = .03) and allele model (P = .03). Seven SNPs had statistically significant on TDT. None of 26 alleles has association with NSCL/P on FBAT. Some SNPs had haplotype-haplotype interactions and genotype-genotype interactions.

CONCLUSION

C14orf49 chr14_95932477 was significantly different between cases and controls on genotype model and allele model by case-control design. Seven SNPs were significantly different on HRR. Four SNPs were significantly different on TDT.

The Dominant Role of Forkhead Box Proteins in Cancer

Forkhead box (FOX) proteins are multifaceted transcription factors that are significantly implicated in cancer, with various critical roles in biological processes. Herein, we provide an overview of several key members of the FOXA, FOXC, FOXM1, FOXO and FOXP subfamilies. Important pathophysiological processes of FOX transcription factors at multiple levels in a context-dependent manner are discussed. We also specifically summarize some major aspects of FOX transcription factors in association with cancer research such as drug resistance, tumor growth, genomic alterations or drivers of initiation. Finally, we suggest that targeting FOX proteins may be a potential therapeutic strategy to combat cancer.

Thyroid cancers of follicular origin in a genomic light: in-depth overview of common and unique molecular marker candidates

In recent years, thyroid malignances have become more prevalent, especially among women. The most common sporadic types of thyroid tumors of follicular origin include papillary, follicular and anaplastic thyroid carcinomas. Although modern diagnosis methods enable the identification of tumors of small diameter, tumor subtype differentiation, which is imperative for the correct choice of treatment, is still troublesome. This review discusses the recent advances in the field of molecular marker identification via next-generation sequencing and microarrays. The potential use of these biomarkers to distinguish among the most commonly occurring sporadic thyroid cancers is presented and compared. Geographical heterogeneity might be a differentiator, although not necessarily a limiting factor, in biomarker selection. The available data advocate for a subset of mutations common for the three subtypes as well as mutations that are unique for a particular tumor subtype. Tumor heterogeneity, a known issue occurring within solid malignancies, is also discussed where applicable. Public databases with datasets derived from high-throughput experiments are a valuable source of information that aid biomarker research in general, including the identification of molecular hallmarks of thyroid cancer.

Genome-Wide Association Studies of Autoimmune Thyroid Diseases, Thyroid Function, and Thyroid Cancer

Thyroid diseases, including autoimmune thyroid diseases and thyroid cancer, are known to have high heritability. Family and twin studies have indicated that genetics plays a major role in the development of thyroid diseases. Thyroid function, represented by thyroid stimulating hormone (TSH) and free thyroxine (T4), is also known to be partly genetically determined. Before the era of genome-wide association studies (GWAS), the ability to identify genes responsible for susceptibility to thyroid disease was limited. Over the past decade, GWAS have been used to identify genes involved in many complex diseases, including various phenotypes of the thyroid gland. In GWAS of autoimmune thyroid diseases, many susceptibility loci associated with autoimmunity (human leukocyte antigen [HLA], protein tyrosine phosphatase, non-receptor type 22 [PTPN22], cytotoxic T-lymphocyte associated protein 4 [CTLA4], and interleukin 2 receptor subunit alpha [IL2RA]) or thyroid-specific genes (thyroid stimulating hormone receptor [TSHR] and forkhead box E1 [FOXE1]) have been identified. Regarding thyroid function, many susceptibility loci for levels of TSH and free T4 have been identified through genome-wide analyses. In GWAS of differentiated thyroid cancer, associations at FOXE1, MAP3K12 binding inhibitory protein 1 (MBIP)-NK2 homeobox 1 (NKX2-1), disrupted in renal carcinoma 3 (DIRC3), neuregulin 1 (NRG1), and pecanex-like 2 (PCNXL2) have been commonly identified in people of European and Korean ancestry, and many other susceptibility loci have been found in specific populations. Through GWAS of various thyroid-related phenotypes, many susceptibility loci have been found, providing insights into the pathogenesis of thyroid diseases and disease co-clustering within families and individuals.

Exploration of the association between FOXE1 gene polymorphism and differentiated thyroid cancer: a meta-analysis

BACKGROUND

Several association analyses and linkage researches indicated that inherited genetic variations effectively influence differentiated thyroid carcinogenesis.

METHODS

The results from 15 published studies on differentiated thyroid carcinoma (DTC) were combined. The genetic model included rs965513, rs944289 and rs1867277. Meta-analyses were performed and cochran's χ² based Q-statistic and I² test were performed to assess heterogeneity using STATA software.

RESULTS

Significant results were noticed for rs965513(Odds Ratio(OR) = 1.162(1.117, 1.208)), rs944289(OR = 1.082(1.035, 1.131)) and rs1867277(OR = 1.415(1.324, 1.512)). In the subgroup analysis by ethnicity, rs965513 polymorphism conferred that risk of Caucasians (OR = 1.168(1.122, 1.215)) was more than that of East Asians of 1.35 (OR = 0.897(0.680, 1.193)).

CONCLUSION

This meta-analysis revealed that common variations of FOXE1 (rs965513, rs944289 and rs1867277) were risk factors associated with increased DTC susceptibility.

Thyroid transcription factor FOXE1 interacts with ETS factor ELK1 to co-regulate TERT

BACKGROUND

Although FOXE1 was initially recognized for its role in thyroid organogenesis, more recently a strong association has been identified between the FOXE1 locus and thyroid cancer. The role of FOXE1 in adult thyroid, and in particular regarding cancer risk, has not been well established. We hypothesised that discovering key FOXE1 transcriptional partners would in turn identify regulatory pathways relevant to its role in oncogenesis.

RESULTS

In a transcription factor-binding array, ELK1 was identified to bind FOXE1. We confirmed this physical association in heterologously transfected cells by IP and mammalian two-hybrid assays. In thyroid tissue, endogenous FOXE1 was shown to bind ELK1, and using ChIP assays these factors bound thyroid-relevant gene promoters TPO and TERT in close proximity to each other. Using a combination of electromobility shift assays, TERT promoter assays and siRNA-silencing, we found that FOXE1 positively regulated TERT expression in a manner dependent upon its association with ELK1. Treating heterologously transfected thyroid cells with MEK inhibitor U0126 inhibited FOXE1-ELK1 interaction, and reduced TERT and TPO promoter activity.

METHODOLOGY

We investigated FOXE1 interactions within in vitro thyroid cell models and human thyroid tissue using a combination of immunoprecipitation (IP), chromatin IP (ChIP) and gene reporter assays.

CONCLUSIONS

FOXE1 interacts with ELK1 on thyroid relevant gene promoters, establishing a new regulatory pathway for its role in adult thyroid function. Co-regulation of TERT suggests a mechanism by which allelic variants in/near FOXE1 are associated with thyroid cancer risk.

rs965513 polymorphism as a common risk marker is associated with papillary thyroid cancer

Papillary thyroid cancer (PTC) is the most common type of thyroid cancer. With the rapid development of genome-wide association studies (GWAS), many genome variants associated with susceptibility to PTC have been identified, including the single nucleotide polymorphism rs965513 (9q22.33) near FOXE1. To evaluate the association between rs965513 and PTC in different ethnicities and countries, we conducted a meta-analysis using relatively large-scale samples from 23 studies (N = 163,136; 20,736 cases and 142,400 controls) by searching the PubMed and Google Scholar databases. Significant heterogeneity caused by different populations among the selected studies was observed. The A allele of rs965513 polymorphism was shown to be highly associated with risk of thyroid cancer, with odds ratios of 1.58 (95% CI 1.32–1.90) in all populations, 1.65 (95% CI 1.31–2.07)) in Caucasian populations and 1.49 in Asian populations. Compared to the dominant and recessive models, we observed the highest odds ratio (OR = 2.80, 95% CI 2.12–3.69) in the homozygous model. These results revealed that the rs965513 polymorphism is a risk factor for thyroid cancer

The Expression of FOXE-1 and STIP-1 in Papillary Thyroid Carcinoma and Their Relationship with Patient Prognosis

BACKGROUND & OBJECTIVE

Most patients with papillary carcinoma of the thyroid gland (PTC) havefavorable outcome,but sinceit has severe capability to invade the nearby tissues, there isa great risk of regional and distal lymph-nodes (LNs) metastases related to poor prognostic parameters, early recurrences, and distant metastasis that lead to bad patient outcome. Discovering other prognostic biomarkers for this cancer helps to detect early recurrences, invasion, expecting patient outcome, and possible use as therapeutic-targets for it. The fork-head-box-E-1(FOX-E-1), with the alternative name of thyroid-transcriptionfactor-2 (TTF-2), is one of thetranscription factors familiesthat is huge and containsa special fork-head-domain. It has a significant role in the differentiation and maturation of thyroid-follicular cells. Stress-induced phosphor-protein-1 (STIP-1), withthe alternative name ofheat-shock-protein-(HSP)organizing protein,is a 62.6-kD protein, with three parts of tetra-trico-peptide repeats (TPR), and is capable of interaction with heat-shock proteins forming structures that haveplethora of roles in variable cellular processes;e.g., cell cycles regulations, transcriptions, and RNA splicing.The current study aimed at exploring the relationship between FOXE-1 and STIP-1 expressions, the clinicopathological parameters, prognosis, and survival of patients with PTC.

METHODS

The current studyexplored FOXE-1 and STIP-1 expressions by the immunohistochemical methods in 36 paraffin blocks retrieved from 36 patients of PTC, analyzed the relationships between their levels of expression,clinicopathological parameters, prognosis, and survival of patients.

RESULTS

The high expression levels forboth FOXE-1 and STIP-1 in PTC were associated with larger size of the tumor, extra-thyroidal extension, vessels invasion, LNs spread (P <0.001), presence of distant metastases (P values = 0.005 and 0.012, respectively) and higher stages of the cancer (P values =0.012 and 0.042, respectively).The FOXE-1 over-expression was associated with shortened distant metastases free survival (DMFS) and shortened five-year overall survival rates (OS) (P <0.001).

CONCLUSION

Patients withadvanced PTC andunfavorable prognosis had high levels of both FOXE-1 and STIP-1 expressions.

Vitamin D, FOXO3a, and Sirtuin1 in Hashimoto's Thyroiditis and Differentiated Thyroid Cancer

Background: Protective effects of vitamin D have been reported in autoimmune and malignant thyroid diseases, though little is known about the underlying mechanism. Sirtuin 1 histon deacethylase (SIRT1) links the vitamin D pathway with regulation of transcription factor FOXO3a, a key player in cell cycle regulation and apoptosis. Aim of the present study was to investigate common single nucleotide polymorphisms (SNP's) in FOXO3a gene in respect to thyroid diseases, as well as to evaluate the hypothesis of Sirtuin1-FOXO3a interaction being a mediator of anti-proliferative vitamin D effects. Methods: The SNP's FOXO3a rs4946936/rs4945816/rs9400239 were genotyped in 257 patients with differentiated thyroid carcinoma (DTC), 139 patients with Hashimoto thyroiditis (HT) and 463 healthy controls (HC). Moreover, T-helper cells of HC and papillary thyroid cancer cell line BCPAP were incubated with 1,25(OH)₂D₃ and/or SIRT1 inhibitor Ex-527 in order to elucidate SIRT1- dependent vitamin D effects on cell proliferation and FOXO3a gene expression in vitro. Results: Patients with DTC tended to carry more often allele C in FOXO3a rs4946936 in comparison to HC (p_corrected = p_c = 0.08). FOXO3a rs9400239T and rs4945816C was more frequent in HT in comparison to HC (p_c = 0.02 and p_c = 0.01, respectively). In both DTC and HT, we could not find a correlation of FOXO3a SNP's with vitamin D status. However, on in vitro level, 1,25(OH)₂D₃ showed an anti-proliferative effect in both T-helper cells and BCPAP, that was blocked by SIRT1 inhibition (T-helper cells: p = 0.0059, BCPAP: p = 0.04) and accompanied by elevated FOXO3a gene expression in T-helper cells (p = 0.05). Conclusions: FOXO3a rs9400239T and rs4945816C may constitute risk factors for HT, independent of the vitamin D status.This indicates the implication of FOXO3a in pathogenesis of autoimmune thyroid diseases. The dependency of anti-proliferative vitamin D effects on SIRT1 activity further suggests a key role of vitamin D-SIRT1-FOXO3a axis for protective vitamin D effects.

FOXE1 Mutation Screening in a Case with Cleft Lip, Hypothyroidism, and Thyroid Carcinoma: A New Syndrome?

A 26-year-old woman is referred to the Internal Medicine consultation due to increases in laboratory studies associated with Papillary Thyroid Carcinoma (PTC) that was confirmed by histopathological studies. Her clinical history revealed that, at 3 months of age, she was successfully treated with surgery for cleft lip (CL) and at the age of 24 years was diagnosed with hypothyroidism. Single nucleotide polymorphisms (SNPs) in FOXE1 and its promoter regions have been associated with various etiologies related to the thyroid, including orofacial clefting, specially cleft palate (CP) and CL, hypothyroidism (HT), and thyroid cancer. The association of CL, HT, and PTC might be component of a new syndrome; however FOXE1 coding region, which has been involved with these entities, has not exhibited mutations or SNPs. Further study of other genes may help in better characterization of the possible syndrome.

Members of FOX family could be drug targets of cancers

FOX families play important roles in biological processes, including metabolism, development, differentiation, proliferation, apoptosis, migration, invasion and longevity. Here we are focusing on roles of FOX members in cancers, FOX members and drug resistance, FOX members and stem cells. Finally, FOX members as drug targets of cancer treatment were discussed. Future perspectives of FOXC1 research were described in the end.

Genome-wide association and expression quantitative trait loci studies identify multiple susceptibility loci for thyroid cancer

Thyroid cancer is the most common cancer in Korea. Several susceptibility loci of differentiated thyroid cancer (DTC) were identified by previous genome-wide association studies (GWASs) in Europeans only. Here we conducted a GWAS and a replication study in Koreans using a total of 1,085 DTC cases and 8,884 controls, and validated these results using expression quantitative trait loci (eQTL) analysis and clinical phenotypes. The most robust associations were observed in the NRG1 gene (rs6996585, P=1.08 × 10-10) and this SNP was also associated with NRG1 expression in thyroid tissues. In addition, we confirmed three previously reported loci (FOXE1, NKX2-1 and DIRC3) and identified seven novel susceptibility loci (VAV3, PCNXL2, INSR, MRSB3, FHIT, SEPT11 and SLC24A6) associated with DTC. Furthermore, we identified specific variants of DTC that have different effects according to cancer type or ethnicity. Our findings provide deeper insight into the genetic contribution to thyroid cancer in different populations.

Association of FOXE1 polyalanine repeat region with thyroid cancer is dependent on tumour size

OBJECTIVE

Polymorphisms in the thyroid transcription factor forkhead factor E1 (FOXE1) gene have been implicated in the genetic susceptibility to differentiated thyroid cancer, but little is known about their effect on tumour characteristics. The objective of this study was to determine the contribution of the FOXE1 polyalanine repeat region to the susceptibility to thyroid cancer and to its clinical characteristics.

DESIGN, PATIENTS AND MEASUREMENTS

A total of 500 patients with sporadic thyroid cancer (440 papillary and 60 follicular thyroid carcinoma) and 502 healthy controls were included in this case-control association study. The number of FOXE1 alanine repeats in each subject was determined by PCR and multiplex fragment analysis by capillary electrophoresis. FOXE1 genotype and allele frequencies among groups were compared by logistic regression and adjusted for sex and age at diagnosis. Data were analysed according to cancer subtype, tumour size and the presence of lymph node or distant metastasis.

RESULTS

FOXE1 alleles with 16 or more alanine repeats were more frequent in patients with tumour size > 1 cm compared to tumour size ≤ 1 cm (adjusted OR 1·44; 95% CI 1·05-1·88; P = 0·019). Genotypes containing at least one allele with 16 or more alanine repeats were associated with larger tumour size (adjusted OR 1·71; 95% CI 1·15-2·57; P = 0·009). No significant differences were observed between cancer subtypes or the presence/absence of metastasis.

CONCLUSIONS

FOXE1 polyalanine repeat polymorphisms are associated with thyroid cancer, but only for tumours larger than 1 cm, suggesting a role in disease progression.

Genotype Analyses in the Japanese and Belarusian Populations Reveal Independent Effects of rs965513 and rs1867277 but Do Not Support the Role of FOXE1 Polyalanine Tract Length in Conferring Risk for Papillary Thyroid Carcinoma

BACKGROUND

Several functional single-nucleotide polymorphisms (SNPs) at the FOXE1 locus on chromosome 9q22.33 have been associated with the risk for papillary thyroid carcinoma (PTC). This study set out to elucidate whether their effects are independent, using genotyping results in populations of Asian and European descent.

METHODS

SNPs rs965513 and rs1867277 and a polymorphic region determining the length of the FOXE1 polyalanine (poly-Ala) tract were genotyped in 501 patients with PTC and 748 healthy individuals from Japan, and in 660 patients and 820 population controls from Belarus. Functional analysis of transactivation activities of FOXE1 isoforms with varying number of alanine repeats was performed by a Dual-Luciferase^® Assay.

RESULTS

All three polymorphisms were significantly associated with PTC in both populations on univariate analysis. However, conditional analysis revealed independent effects of rs965513 and rs1867277 SNPs but not of the FOXE1 poly-Ala polymorphism. The independent effect of the lead rs965513 SNP was observed in both populations, while that of rs1867277 was only identified in the Japanese population, in which linkage disequilibrium between the three polymorphisms is markedly weaker. Despite the strong decrease in transcriptional activity with increasing FOXE1 poly-Ala tract length, no difference in transactivation potential of the FOXE1 poly-Ala isoforms could be seen after adjustment for the minimal promoter activity in the reporter vectors. Plasmids encoding FOXE1 isoforms of increasing poly-Ala tract length were also found to produce less FOXE1 protein after cell transfection.

CONCLUSIONS

The functional variants rs965513 and rs1867277 independently contribute to genetic predisposition to PTC, while a contributing role of the FOXE1 poly-Ala polymorphism could not be confirmed.

Clinical features of Hispanic thyroid cancer cases and the role of known genetic variants on disease risk

Thyroid cancer (TC) is the second most common cancer among Hispanic women. Recent genome-wide association (GWA) and candidate studies identified 6 single nucleotide polymorphisms (SNPs; rs966423, rs2439302, rs965513, rs6983267, rs944289, and rs116909374), associated with increased TC risk in Europeans but their effects on disease risk have not been comprehensively tested in Hispanics. In this study, we aimed to describe the main clinicopathological manifestations and to evaluate the effects of known SNPs on TC risk and on clinicopathological manifestations in a Hispanic population.We analyzed 281 nonmedullary TC cases and 1146 cancer-free controls recruited in a multicenter population-based study in Colombia. SNPs were genotyped by Kompetitive allele specific polymerase chain reaction (KASP) technique. Association between genetic variants and TC risk was assessed by computing odds ratios (OR) and confidence intervals (CIs).Consistent with published data in U.S. Hispanics, our cases had a high prevalence of large tumors (>2 cm, 43%) and a high female/male ratio (5:1). We detected significant associations between TC risk and rs965513A (OR = 1.41), rs944289T (OR = 1.26), rs116909374A (OR = 1.96), rs2439302G (OR = 1.19), and rs6983267G (OR = 1.18). Cases carried more risk alleles than controls (5.16 vs. 4.78, P = 4.8 × 10). Individuals with ≥6 risk alleles had >6-fold increased TC risk (OR = 6.33, P = 4.0 × 10) compared to individuals with ≤2 risk alleles. rs944289T and rs116909374A were strongly associated with follicular histology (ORs = 1.61 and 3.33, respectively); rs2439302G with large tumors (OR = 1.50); and rs965513A with regional disease (OR = 1.92).To our knowledge, this is the first study of known TC risk variants in South American Hispanics and suggests that they increase TC susceptibility in this population and can identify patients at higher risk of severe disease.

Molecular genetics of thyroid cancer

The pathogenesis of the development and progression of thyroid cancer (TC) is far from being clear at present. Accumulated evidence suggests that it is a complex polygenic disorder for which genetic factors play an important role in disease aetiology. Here we review the literature to report the genetic variations and alterations that have been described in the aetiology of TC. The functional effects of some mutations and single nucleotide polymorphisms on TC are validated, establishing the role of sequence variations in this cancer. However, large prospective studies are still required to evaluate the diagnostic and prognostic value of these genetic determinants in clinical practice.

TITF1 and TITF2 loci variants indicate significant associations with thyroid cancer

A number of studies have investigated the influence of TITF1 and TITF2 genetic variants on thyroid carcinogenesis, but their associations remain unclear due to the controversial results. The objective of this study was to test the hypothesis that TITF1 and TITF2 variants modulate thyroid cancer susceptibility. Eligible studies were identified through online searches supplemented by manual search. Either the DerSimonian and Laird method or the Mantel-Haenszel method was used to estimate the risk of thyroid cancer (ORs and 95 % CIs). The pooled ORs were calculated assuming the allele model. We identified a total of 10 publications concerning the topic of interest. Overall, meta-analysis of rs944289 showed 1.11-fold increased risk of thyroid cancer related to the risk T allele (T vs. C: OR 1.11, 95 % CI 1.05-1.17). For rs965513, individuals carrying the risk A allele, compared to individuals with the G allele, had 31 % higher risk of thyroid cancer (A vs. G: OR 1.31, 95 % CI 1.17-1.46). Analyses in total samples for rs1867277, rs1443434, and rs907580 yielded similar associations (A vs. G: OR 1.22, 95 % CI 1.06-1.39; G vs. T: OR 1.26, 95 % CI 1.09-1.45; T vs. C: OR 1.42, 95 % CI 1.21-1.66, respectively). The significant association persisted among Caucasians in subgroup analyses for rs944289 and rs965513. The genetic susceptibility of thyroid cancer seems likely to be associated with the risk allele at rs944289 in the TITF1 gene and at rs1867277, rs965513, rs1443434, and rs907580 in the TITF2 gene.

Replication and Meta-Analysis of Common Gene Mutations in TTF1 and TTF2 with Papillary Thyroid Cancer

Papillary thyroid cancer (PTC), one of the most common malignant thyroid tumors, exits widely in the thyroid of adolescents. Thyroid transcription factor 1 (TTF1) and 2 (TTF2) were thyroid-specific transcription factors, and regulated expression of the thyroid-specific genes. Hence, the aim of the present study was to evaluate the correlation between gene variants of TTF1 and TTF2 and the risk of PTC in Chinese population.Two tagging single-nucleotide polymorphisms (tSNPs) on TTF1 and TTF2 were selected and genotyped by matrix-assisted laser desorption/ionization time-of-flight (MALDITOF) mass spectrometry in a hospital-based case-control study of 297 PTC patients and 594 healthy controls. Furthermore, a meta-analysis of the association between TTF1 and TTF2 and PTC risk was also performed.We found that the rs944289 on the TTF1 was significantly associated with increased PTC risk (TT vs CC, OR = 1.53, 95% CI = 1.05-2.24; CT + TT vs TT, OR = 1.34, 95% CI = 1.00-1.79; T vs C, OR = 1.27, 95% CI = 1.04-1.55). Similarly, the rs965513 on the TTF2 can also elevate the risk of PTC significantly (GA vs GG, OR = 1.67, 95% CI = 1.07-2.59; AA+GA vs AA, OR = 1.37, 95% CI = 1.09-1.82; A vs G, OR = 1.29, 95% CI = 1.05-1.59). Furthermore, results of stratified analysis revealed that the risk effects of rs944289 and rs965513 were more overpowering in the subgroups of patients with MNG, as well as subjects without metastasis. Results of meta-analysis from the previous study and our new data indicated that variants of rs944289 and rs965513 might be the genetic susceptible factors both in Asians and Caucasians.We get the conclusion that mutations of TTF1 and TTF2 are significantly associated with an increasing risk of PTC in Chinese. However, more detailed investigations and further large-scale studies on genetic functions to provide more conclusive and accurate evidence are required in the future.

Somatic Mutations of FOXE1 in Papillary Thyroid Cancer

BACKGROUND

Population-based studies have demonstrated an association of single nucleotide polymorphisms close to the thyroid transcription factor forkhead box E1 (FOXE1) gene with thyroid cancer. The dysregulation of forkhead proteins is increasingly recognized to play a role in the development and progression of cancer. The objective of the study was to seek to identify novel mutations in FOXE1 in papillary thyroid cancer (PTC) and to assess the effect of these mutations on protein expression and transcriptional function on FOXE1 responsive promoters.

METHODS

The study was conducted at two tertiary referral hospitals. The coding region of FOXE1 was sequenced in tissue-derived DNA or RNA from 120 patients with PTC and 110 patients with multinodular goiter (MNG). In vitro studies were performed to examine the protein expression and transcriptional function of FOXE1 mutants. A molecular model of the forkhead domain (FHD) of FOXE1 was generated using the SWISS-MODEL online server with the three-dimensional structure of FOXD3 as a template.

RESULTS

Three somatic missense mutations were detected in PTC resulting in the amino acid substitutions P54Q, K95Q, and L112F. One additional mutation was detected in a MNG (G140R). In vitro studies demonstrated marked impairment in transcriptional activation by all four FOXE1 mutants, which was not explained by differences in protein expression. Molecular modeling localized three of the mutations to highly conserved regions of the FHD.

CONCLUSIONS

We have identified novel somatic mutations of FOXE1 in PTC. Mutational inactivation of FOXE1 is an uncommon event in thyroid tumors but may contribute to thyroid carcinogenesis and dedifferentiation in concert with other oncogenic drivers.

Multiple functional variants in long-range enhancer elements contribute to the risk of SNP rs965513 in thyroid cancer

The [A] allele of SNP rs965513 in 9q22 has been consistently shown to be highly associated with increased papillary thyroid cancer (PTC) risk with an odds ratio of ∼1.8 as determined by genome-wide association studies, yet the molecular mechanisms remain poorly understood. Previously, we noted that the expression of two genes in the region, forkhead box E1 (FOXE1) and PTC susceptibility candidate 2 (PTCSC2), is regulated by rs965513 in unaffected thyroid tissue, but the underlying mechanisms were not elucidated. Here, we fine-mapped the 9q22 region in PTC and controls and detected an ∼33-kb linkage disequilibrium block (containing the lead SNP rs965513) that significantly associates with PTC risk. Chromatin characteristics and regulatory element signatures in this block disclosed at least three regulatory elements functioning as enhancers. These enhancers harbor at least four SNPs (rs7864322, rs12352658, rs7847449, and rs10759944) that serve as functional variants. The variant genotypes are associated with differential enhancer activities and/or transcription factor binding activities. Using the chromosome conformation capture methodology, long-range looping interactions of these elements with the promoter region shared by FOXE1 and PTCSC2 in a human papillary thyroid carcinoma cell line (KTC-1) and unaffected thyroid tissue were found. Our results suggest that multiple variants coinherited with the lead SNP and located in long-range enhancers are involved in the transcriptional regulation of FOXE1 and PTCSC2 expression. These results explain the mechanism by which the risk allele of rs965513 predisposes to thyroid cancer.

Genetic predisposition to papillary thyroid carcinoma: involvement of FOXE1, TSHR, and a novel lincRNA gene, PTCSC2

CONTEXT

By genome-wide association studies, the risk allele [A] of SNP rs965513 predisposes strongly to papillary thyroid carcinoma (PTC). It is located in a gene-poor region of 9q22, some 60 kb from the FOXE1 gene. The underlying mechanisms remain to be discovered.

OBJECTIVE

Our objective was to identify novel transcripts in the 9q22 locus and correlate gene expression levels with the genotypes of rs965513.

DESIGN

We performed 3' and 5' rapid amplification of cDNA ends and RT-PCR to detect novel transcripts. One novel transcript was forcibly expressed in a cell line followed by gene expression array analysis. We genotyped rs965513 from PTC patients and measured gene expression levels by real-time RT-PCR in unaffected thyroid tissue and matched tumor.

SETTING

This was a laboratory-based study using cells from clinical tissue samples and a cancer cell line.

MAIN OUTCOME MEASURES

We detected previously uncharacterized transcripts and evaluated the gene expression levels and the correlation with the risk allele of rs965513, age, gender, chronic lymphocyte thyroiditis (CLT), and TSH levels.

RESULTS

We found a novel long intergenic noncoding RNA gene and named it papillary thyroid cancer susceptibility candidate 2 (PTCSC2). Transcripts of PTCSC2 are down-regulated in PTC tumors. The risk allele [A] of rs965513 was significantly associated with low expression of unspliced PTCSC2, FOXE1, and TSHR in unaffected thyroid tissue. We also observed a significant association of age and CLT with PTCSC2 unspliced transcript levels. The correlation between the rs965513 genotype and the PTCSC2 unspliced transcript levels remained significant after adjusting for age, gender, and CLT. Forced expression of PTCSC2 in the BCPAP cell line affected the expression of a subset of noncoding and coding transcripts with enrichment of genes functionally involved in cell cycle and cancer.

CONCLUSIONS

Our data suggest a role for PTCSC2, FOXE1, and TSHR in the predisposition to PTC.

Common genetic variants on FOXE1 contributes to thyroid cancer susceptibility: evidence based on 16 studies

Genome-wide association studies have identified polymorphisms at chromosome 9q22.23 as a new thyroid cancer (TC) susceptibility locus in populations of European descent. Since then, the relationship between three common variations (rs965513, rs1867277, and rs71369530) of FOXE1 and TC has been reported in various ethnic groups; however, the results have been inconclusive. To derive a more precise estimation of the relationship as well as to quantify the between-study heterogeneity and potential bias, a meta-analysis including 120,258 individuals from 16 studies was performed. An overall random-effect per-allele odds ratio (OR) of 1.74 (95 % confidence interval (95 % CI), 1.62-1.86, P<10(-5)) and 1.62 (95 % CI, 1.50-1.76, P<10(-5)) was found for the rs965513 and rs1867277 polymorphisms, respectively. In addition, we also detected significant association of FOXE1 polyalanine tract (rs71369530) with TC risk (OR=2.01; 95 % CI, 1.66-2.44, P<10(-5)). Significant associations were also detected under dominant and recessive genetic models. In the subgroup analysis by ethnicity, significantly increased risks were found for the rs965513 polymorphism among Caucasians (OR=1.79; 95 % CI, 1.69-1.91, P<10(-5)) and Asians (OR=1.42; 95 % CI, 1.12-1.81, P=0.004). Ethnicity was identified as a potential source of between-study heterogeneity for rs965513. When stratified by sample size, study design, histological types of TC, and radiation exposure status, significantly increased risks were found for the rs965513 polymorphism. This meta-analysis demonstrated that the three common variations on FOXE1 is a risk factor associated with increased TC susceptibility, but these associations vary in different ethnic populations.