AHR over-expression in papillary thyroid carcinoma: clinical and molecular assessments in a series of Italian acromegalic patients with a long-term follow-up

A review of complex hormone regulation in thyroid cancer: novel insights beyond the hypothalamus-pituitary-thyroid axis

Like the ovaries and prostate, the thyroid exhibits characteristic hormone secretion and regulation. Thyroid cancer (TC), especially differentiated thyroid carcinoma, has typical sex-specific and age-specific hormone-driven clinical features. Previous research has primarily focused on the effects of thyroid stimulating hormone, thyroid hormones, and estrogens on the onset and progression of TC, while the roles of growth hormone (GH), androgens, and glucocorticoids have largely been overlooked. Similarly, few studies have investigated the interactions between hormones and hormone systems. In fact, numerous studies of patients with acromegaly have shown that serum levels of GH and insulin-like growth factor-1 (IGF-1) may be associated with the onset and progression of TC, although the influences of age, sex, and other risk factors, such as obesity and stress, remain unclear. Sex hormones, the GH/IGF axis, and glucocorticoids are likely involved in the onset and progression of TC by regulating the tumor microenvironment and metabolism. The aim of this review was to clarify the roles of hormones and hormone systems in TC, especially papillary thyroid carcinoma, as references for further investigations.

Bioluminescence imaging of Cyp1a1-luciferase reporter mice demonstrates prolonged activation of the aryl hydrocarbon receptor in the lung

Aryl hydrocarbon receptor (AHR) signalling integrates biological processes that sense and respond to environmental, dietary, and metabolic challenges to ensure tissue homeostasis. AHR is a transcription factor that is inactive in the cytosol but upon encounter with ligand translocates to the nucleus and drives the expression of AHR targets, including genes of the cytochrome P4501 family of enzymes such as Cyp1a1. To dynamically visualise AHR activity in vivo, we generated reporter mice in which firefly luciferase (Fluc) was non-disruptively targeted into the endogenous Cyp1a1 locus. Exposure of these animals to FICZ, 3-MC or to dietary I3C induced strong bioluminescence signal and Cyp1a1 expression in many organs including liver, lung and intestine. Longitudinal studies revealed that AHR activity was surprisingly long-lived in the lung, with sustained Cyp1a1 expression evident in discrete populations of cells including columnar epithelia around bronchioles. Our data link diet to lung physiology and also reveal the power of bespoke Cyp1a1-Fluc reporters to longitudinally monitor AHR activity in vivo.

Clinical presentation and management of acromegaly in elderly patients

BACKGROUND AND AIM

Acromegaly is a rare disease with a peak of incidence in early adulthood. However, enhanced awareness of this disease, combined with wide availability of magnetic resonance imaging (MRI), has increased the diagnosis of forms with mild presentation, especially in elderly patients. Moreover, due to increased life expectancy and proactive individualized treatment, patients with early-onset acromegaly are today aging. The aim of our study was to describe our cohort of elderly patients with acromegaly.

MATERIALS AND METHODS

This is a cross-sectional retrospective study of 96 outpatients. Clinical, endocrine, treatment, and follow-up data were collected using the electronic database of the University Hospital of Padova, Italy.

RESULTS

We diagnosed acromegaly in 13 patients, aged ≥65 years, presenting with relatively small adenomas and low IGF-1 secretion. Among them, 11 patients were initially treated with medical therapy and half normalized hormonal levels after 6 months without undergoing neurosurgery (TNS). Remission was achieved after TNS in three out of four patients (primary TNS in two); ten patients presented controlled acromegaly at the last visit. Acromegaly-related comorbidities (colon polyps, thyroid cancer, adrenal incidentaloma, hypertension, and bone disease) were more prevalent in patients who had an early diagnosis (31 patients, characterized by a longer follow-up of 24 years) than in those diagnosed aged ≥65 years (5 years of follow-up).

CONCLUSIONS

Elderly acromegalic patients are not uncommon. Primary medical therapy is a reasonable option and is effectively used, while the rate of surgical success is not reduced. A careful cost-benefit balance is suggested. Disease-specific comorbidities are more prevalent in acromegalic patients with a longer follow-up rather than in those diagnosed aged ≥65 years.

Papillary Thyroid Carcinoma in Patients with Acromegaly from a Single Center in China

OBJECTIVES

An increased risk of thyroid cancers in patients with acromegaly has been addressed by numerous studies. However, the differences between patients with papillary thyroid cancer (PTC) with and without acromegaly remain to be clarified. We compared the clinical-pathologic data and genetic alterations of PTC between the 2 groups.

PATIENTS AND METHODS

Four patients with PTC and acromegaly and 32 age-matched patients with PTC without acromegaly were retrieved retrospectively from the hospital recordings. Mutational analysis was determined by direct sequencing. Insulin-like growth factor-1 receptor and insulin Rβ expression were analyzed by immunohistochemistry in acromegaly group.

RESULTS

The prevalence of multifocality involved in bilateral lobes in the acromegaly group was significantly increased (P = 0.017). The presence of bilateral lymph node metastasis showed the increasing trend even though without a significant difference because of the limited number of PTC patients in acromegaly group (P = 0.053). There was no significant difference in other factors, such as sex, tumor size in maximum diameter, lymph node metastasis, extrathyroidal extension, and TNM stage. Two (50%) PTCs in acromegalic group and 25 (78.12%) PTCs in the nonacromegalic group were detected to harbor BRAF^600E mutation, and no patient was identified to have NRAS codon 61, KRAS codon 61/12/13 mutation. Insulin-like growth factor-1 receptor and insulin Rβ immunostaining showed low positive to positive in PTC cells and negative in adjacent normal tissues in patients with acromegaly.

CONCLUSIONS

Multifocality involved in 2 lobes is more common in patients with PTC and acromegaly, which shows more aggressive behaviors. BRAF mutation is not uncommon in patients with PTC and acromegaly.

Prevalence of thyroid cancer in patients with acromegaly and non-growth hormone secreting pituitary adenomas: A prospective cross-sectional study

OBJECTIVE

To evaluate the prevalence of differentiated thyroid cancer (DTC) in patients with non-GH secreting pituitary adenomas [NGHPA group: non-functioning (NFPA), prolactin (PRL) and corticotropin (ACTH)-secreting adenomas] compared to patients with acromegaly, a pituitary disease that has been associated with increased risk for thyroid cancer.

PATIENTS AND METHODS

Prospective, cross-sectional study involving consecutive outpatients followed in our institution with diagnosis of acromegaly (n = 71; 43 women, median age 57 yrs) and NGHPA (n = 57; 38 women, median age 48 yrs.; PRL (n = 35), ACTH (n = 7), NFPA (n = 15). All participants were subjected to thyroid ultrasound (US) by the same examiner, and US-guided fine needle aspiration (FNA) biopsy when indicated.

RESULTS

Thyroid volume was higher in acromegaly than in NGHPA (median 12.5 ml vs 6.3 ml; p < 0.0001), and thyroid nodules were present in 27/71 (38.0%) of acromegaly patients and in 14/57 (24.6%) of NGHPA group. FNA was indicated in 15/27 (55.5%) of acromegaly patients [Bethesda I (n = 1); II (n = 11), III (n = 1), two patients refused FNA], and in 8/14 (57.1%) of the NGHPA group [Bethesda I (n = 2); II (n = 4); V (n = 1); VI (n = 1)]. The two patients of NGHPA group with Bethesda V and VI were operated and papillary carcinoma was confirmed histologically.

CONCLUSION

DTC was not detected in our acromegaly patients and its presence in patients with NGHPA suggests that DTC predisposition is not related to GH excess.

IGF Bioregulation System in Benign and Malignant Thyroid Nodular Disease: A Systematic Review

BACKGROUND/AIM

The insulin-like growth factor bioregulation system is implicated in cancer biology. Herein, we aim to review the evidence on the expression of the insulin-like growth factor 1 and 2 (IGF1 and IGF2), their receptors (IGF-Rs) and IGF-binding proteins (IGFBPs) in thyroid tissue and their possible association with benign and malignant thyroid nodular diseases.

MATERIALS AND METHODS

We systematically reviewed Pubmed and Scopus databases up to May 2020. A total of 375 articles were retrieved and analyzed.

RESULTS

Among 375 articles, 45 were included in this systematic review study. IGF1 was investigated in 31 studies, IGF2 in 1, IGF1 receptor in 15 and IGF-binding proteins in 13 articles. IGF1 expression in humans was dependent on the number and compound of benign nodules as well as the method of measurement. In differentiated thyroid carcinoma, a positive correlation between IGF1 and immunohistological stage was documented in some studies while in others only a positive trend was observed. IGF-1R and IGFBPs expression was higher in malignant rather than benign lesions. There was only a positive trend for increased IGF2 expression in malignancy, while IGFBPs were in most studies statistically increased in various cancer types compared to benign nodular disease.

CONCLUSION

The present data demonstrate that in most studies there is statistically positive expression of IGF-1 and less of IGF-2 in thyroid cancer compared to normal thyroid tissue.

The role of AIP variants in pituitary adenomas and concomitant thyroid carcinomas in the Netherlands: a nationwide pathology registry (PALGA) study

PURPOSE

Germline mutations in the aryl-hydrocarbon receptor interacting protein (AIP) have been identified often in the setting of familial isolated pituitary adenoma (FIPA). To date there is no strong evidence linking germline AIP mutations to other neoplasms apart from the pituitary. Our primary objective was to investigate the prevalence of AIP gene mutations and mutations in genes that have been associated with neuroendocrine tumors in series of tumors from patients presenting with both pituitary adenomas and differentiated thyroid carcinomas (DTCs).

METHODS

Pathology samples were retrieved from all pituitary adenomas in patients with concomitant DTCs, including one with a known germline AIP variant. Subsequently, two additional patients with known germline AIP variants were included, of which one presented only with a follicular thyroid carcinoma (FTC).

RESULTS

In total, 17 patients (14 DTCs and 15 pituitary adenomas) were investigated by targeted next generation sequencing (NGS). The pituitary tumor samples revealed no mutations, while among the thyroid tumor samples BRAF (6/14, 42.9%) was the most frequently mutated gene, followed by NRAS (3/11, 27.3%). In one AIP-mutated FIPA kindred, the AIP-variant c.853C>T; p.Q285* was confirmed in the FTC specimen, including evidence of loss of heterozygosity (LOH) at the AIP locus in the tumor DNA.

CONCLUSION

Although most observed variants in pituitary adenomas and DTCs were similar to those of sporadic DTCs, we confirmed in one AIP mutation-positive case the AIP-variant and LOH at this locus in an FTC specimen, which raises the potential role of the AIP mutation as a rare initiating event.

The Aryl Hydrocarbon Receptor Is Expressed in Thyroid Carcinoma and Appears to Mediate Epithelial-Mesenchymal-Transition

Aryl hydrocarbon receptor (AhR) is expected to promote initiation, progression and invasion of cancer cells regulating proliferation, differentiation, gene expression, inflammation, cell motility and migration. Furthermore, an immunosuppressant function of AhR has been recognized. This study evaluated AhR expression and its role in thyroid cancer progression. AhR expression was assessed by qPCR in 107 thyroid cancer samples (90 PTCs, 11 MTCs, 6 ATCs), and by immunohistochemistry in 41 PTCs. To estimate receptor activation, the expression of target genes CYP1A1 and CYP1B1 was measured. AhR functional effects were evaluated in kynurenine-stimulated FTC-133 and BcPap cell lines by analyzing the expression of genes involved in EMT and cell motility. AhR mRNA expression resulted significantly higher in all the analyzed thyroid cancer samples compared to normal thyroid and a statistically significant correlation with CYP1B1 was detected. Kynurenine-stimulated FTC-133 and BcPap showed the activation of a specific AhR-driven EMT program characterized by E-cadherin decrease and SLUG, N-cadherin and fibronectin increase, resulting in boost of cell motility and invasion. This study confirmed the importance of the IDO1-Kyn-AhR pathway in thyroid cancer tumorigenesis, suggesting an AhR pivotal role in mediating an immunosuppressive microenvironment and favoring the acquisition of a mesenchymal phenotype that could promote invasiveness and metastasis.

Cecal Tumorigenesis in Aryl Hydrocarbon Receptor-Deficient Mice Depends on Cecum-Specific Mitogen-Activated Protein Kinase Pathway Activation and Inflammation

The aryl hydrocarbon receptor (AhR) is a transcription factor known as a dioxin receptor. Recently, Ahr^-/- mice were revealed to develop cecal tumors with inflammation and Wnt/β-catenin pathway activation. However, whether β-catenin degradation is AhR dependent remains unclear. To determine whether other signaling pathways function in Ahr^-/- cecal tumorigenesis, we investigated histologic characteristics of the tumors and cytokine/chemokine production in tumors and Ahr^-/- peritoneal macrophages. AhR expression was also assessed in human colorectal carcinomas. Of the 28 Ahr^-/- mice, 10 developed cecal lesions by 50 weeks of age, an incidence significantly lower than previously reported. Cecal lesions of Ahr^-/- mice developed from serrated hyperplasia to adenoma/dysplasia-like neoplasia with enhanced proliferation. Macrophage and neutrophil infiltration into the lesions was also observed early in serrated hyperplasia, although adjacent mucosa was devoid of inflammation. Il1b, Il6, Ccl2, and Cxcl5 were up-regulated at lesion sites, whereas only IL-6 production increased in Ahr^-/- peritoneal macrophages after lipopolysaccharide + ATP stimulation. Neither Myc (alias c-myc) up-regulation nor β-catenin nuclear translocation was observed, unlike previously reported. Interestingly, enhanced phosphorylation of extracellular signal-regulated kinase, Src, and epidermal growth factor receptor and Amphiregulin up-regulation at Ahr^-/- lesion sites were detected. In human serrated lesions, however, AhR expression in epithelial cells was up-regulated despite morphologic similarity to Ahr^-/- cecal lesions. Our results suggest novel mechanisms underlying Ahr^-/- cecal tumorigenesis, depending primarily on cecum-specific mitogen-activated protein kinase pathway activation and inflammation.

Systems Biology Approaches to Investigate Genetic and Epigenetic Molecular Progression Mechanisms for Identifying Gene Expression Signatures in Papillary Thyroid Cancer

Thyroid cancer is the most common endocrine cancer. Particularly, papillary thyroid cancer (PTC) accounts for the highest proportion of thyroid cancer. Up to now, there are few researches discussing the pathogenesis and progression mechanisms of PTC from the viewpoint of systems biology approaches. In this study, first we constructed the candidate genetic and epigenetic network (GEN) consisting of candidate protein–protein interaction network (PPIN) and candidate gene regulatory network (GRN) by big database mining. Secondly, system identification and system order detection methods were applied to prune candidate GEN via next-generation sequencing (NGS) and DNA methylation profiles to obtain the real GEN. After that, we extracted core GENs from real GENs by the principal network projection (PNP) method. To investigate the pathogenic and progression mechanisms in each stage of PTC, core GEN was denoted in respect of KEGG pathways. Finally, by comparing two successive core signaling pathways of PTC, we not only shed light on the causes of PTC progression, but also identified essential biomarkers with specific gene expression signature. Moreover, based on the identified gene expression signature, we suggested potential candidate drugs to prevent the progression of PTC with querying Connectivity Map (CMap).

Systemic Complications of Acromegaly and the Impact of the Current Treatment Landscape: An Update

Acromegaly is a chronic systemic disease with many complications and is associated with increased mortality when not adequately treated. Substantial advances in acromegaly treatment, as well as in the treatment of many of its complications, mainly diabetes mellitus, heart failure, and arterial hypertension, were achieved in the last decades. These developments allowed change in both prevalence and severity of some acromegaly complications and furthermore resulted in a reduction of mortality. Currently, mortality seems to be similar to the general population in adequately treated patients with acromegaly. In this review, we update the knowledge in complications of acromegaly and detail the effects of different acromegaly treatment options on these complications. Incidence of mortality, its correlation with GH (cumulative exposure vs last value), and IGF-I levels and the shift in the main cause of mortality in patients with acromegaly are also addressed.

The emerging role for Cullin 4 family of E3 ligases in tumorigenesis

As a member of the Cullin-RING ligase family, Cullin-RING ligase 4 (CRL4) has drawn much attention due to its broad regulatory roles under physiological and pathological conditions, especially in neoplastic events. Based on evidence from knockout and transgenic mouse models, human clinical data, and biochemical interactions, we summarize the distinct roles of the CRL4 E3 ligase complexes in tumorigenesis, which appears to be tissue- and context-dependent. Notably, targeting CRL4 has recently emerged as a noval anti-cancer strategy, including thalidomide and its derivatives that bind to the substrate recognition receptor cereblon (CRBN), and anticancer sulfonamides that target DCAF15 to suppress the neoplastic proliferation of multiple myeloma and colorectal cancers, respectively. To this end, PROTACs have been developed as a group of engineered bi-functional chemical glues that induce the ubiquitination-mediated degradation of substrates via recruiting E3 ligases, such as CRL4 (CRBN) and CRL2 (pVHL). We summarize the recent major advances in the CRL4 research field towards understanding its involvement in tumorigenesis and further discuss its clinical implications. The anti-tumor effects using the PROTAC approach to target the degradation of undruggable targets are also highlighted.

GH, IGF-1, and Age Are Important Contributors to Thyroid Abnormalities in Patients with Acromegaly

PURPOSE

To determine the prevalence, risk factors, and possible mechanisms of structural and endocrinological changes to the thyroid in acromegaly.

METHODS

We studied 93 acromegalic patients from PUMCH between January 2013 and December 2013. The demographic and clinical information were recorded. Specimens of pituitary adenomas and thyroid cancer were collected for BRAF mutation assessments.

RESULTS

Thyroid morphological abnormalities were found in 72 (77.4%) patients. Three (3.2%) were diagnosed with thyroid cancer. The thyroid gland volume was significantly increased in patients with higher random GH (p = 0.01), higher nadir GH (p = 0.008), and higher IGF-1 level (p = 0.018). Age (p = 0.002) was an independent risk factor for thyroid morphological abnormalities in acromegaly. The GH burden was significantly higher in patients with thyroid morphological abnormalities (p = 0.036). The BRAF V600E mutation was detected in the PTCs of the two patients with thyroid cancer.

CONCLUSIONS

Both benign and malignant thyroid abnormalities are increased in the acromegalic population compared to those in the general population. Age at diagnosis is an independent risk factor for thyroid abnormalities, and GH burden may be a partial contributor. Early diagnosis, early treatment, and monitoring of postoperational endocrine levels are important for acromegalic patients.

Acromegaly, genetic variants of the aryl hydrocarbon receptor pathway and environmental burden

Increasing evidence suggests that environmental contaminants can exert endocrine disruptors activities and that pollution exposition can have a role in tumorigenic processes. Several environmental pollutants have been shown to affect pituitary cells biology and function. The aryl hydrocarbon receptor (AHR) pathway is involved in xenobiotics' metabolism and in tumorigenesis. A deregulation of the AHR pathway could have a role in pituitary tumours' pathophysiology, especially in the GH secreting ones. AHR-interacting protein (AIP) is one of the key partners of AHR and is implicated in pituitary tumours' pathogenesis. Moreover, an increased prevalence of acromegaly has been reported in a highly polluted area of the province of Messina (Sicily, Italy). Nevertheless, at present, few data are available about the potential role of environmental factors in the pathogenesis and clinical expression of GH secreting pituitary tumours. This review is aimed at discussing the evidences on the potential links among environmental pollutants, the AHR pathway and the pathophysiology of GH-secreting pituitary adenomas.

GH-secreting pituitary macroadenoma (acromegaly) associated with progressive dental malocclusion and refractory CPAP treatment

Background

A link between progressive dental malocclusion, the use of a continuous positive airway pressure mask and GH-secreting pituitary macroadenoma (acromegaly) has not been previously reported. The present clinicopathological analysis stresses that tooth malposition should not be seen exclusively as a local process.

Case presentation

A 62-year-old caucasian man with no relevant medical history reported difficulty chewing food and perceived voice alteration during his annual periodontal check-up. He also referred stiffness of the tongue, face, and submandibular area. The patient had been diagnosed with obstructive sleep apnea syndrome two years previously, since when he had worn a continuous positive airway pressure device during sleep. Exploration of the occlusion revealed significant changes: an atypical left lateral and anterior open bite with major buccoversion of teeth 33, 34, 35, 36. Inspection of the soft tissue revealed only macroglossia, although external palpation indicated a subcutaneous stiffness of the submandibular area. General analytical tests, including hormone profiles, and magnetic resonance imaging confirmed the diagnosis of acromegaly induced by a pituitary adenoma. Intrasellar tumor resection via transsphenoidal approach was performed. After surgery, the patient already noted a marked improvement of all symptoms associated with the acromegaly. Desaturation data also evolved favourably and the pulmonologist advised the patient to abandon the continuous positive airway pressure treatment.

Conclusion

Progressive dental malocclusion may be associated with a systemic disease and the use of a nasal mask with premaxillary support may distort the diagnosis of acromegaly.

MANAGEMENT OF ENDOCRINE DISEASE: Acromegaly and cancer: an old debate revisited

Based on experimental and animal models, epidemiological data from non-acromegaly populations, and longitudinal and cross-sectional cohorts of patients with acromegaly, a potential association between acromegaly and cancer has long been hypothesized, in particular colorectal cancer, and, to a lesser extent, breast, thyroid and prostate cancers. The exact mechanisms underlying this potential association have not been fully elucidated. Results from studies examining cancer incidence and mortality in acromegaly have been inconsistent, with some demonstrating increased risk, whereas others show no increase. This article reviews the existing data relating to cancer risk and mortality in acromegaly, exploring the limitations of study designs and the impact of changes in disease control and patient outcomes over time.

A constitutive active MAPK/ERK pathway due to BRAFV600E positively regulates AHR pathway in PTC

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor mediating the toxicity and tumor-promoting properties of dioxin. AHR has been reported to be overexpressed and constitutively active in a variety of solid tumors, but few data are currently available concerning its role in thyroid cancer. In this study we quantitatively explored a series of 51 paired-normal and papillary thyroid carcinoma (PTC) tissues for AHR-related genes. We identified an increased AHR expression/activity in PTC, independently from its nuclear dimerization partner and repressor but strictly related to a constitutive active MAPK/ERK pathway. The AHR up-regulation followed by an increased expression of AHR target genes was confirmed by a meta-analysis of published microarray data, suggesting a ligand-independent active AHR pathway in PTC. In-vitro studies using a PTC-derived cell line (BCPAP) and HEK293 cells showed that BRAF^V600E may directly modulate AHR localization, induce AHR expression and activity in an exogenous ligand-independent manner. The AHR pathway might represent a potential novel therapeutic target for PTC in the clinical practice.

Sleep apnea syndrome in endocrine clinics

Obstructive sleep apnea syndrome (OSAS) is a chronic condition with a high prevalence (up to 7 % of the general population) characterized by frequent episodes of upper airway collapse while sleeping. Left untreated, OSAS can cause severe complications, including systemic hypertension, cardiovascular disease, stroke, and abnormal glucose metabolism. This review aims to summarize the close links between OSAS, endocrinology, and metabolism. In patients with metabolic syndrome, OSAS is an independent risk factor for the onset of type 2 diabetes and a worsening glycemic control. The accumulation of adipose tissue in the neck and limited chest wall dynamics, hypoxia, and local micro-inflammation link visceral obesity closely with OSAS. There is now an abundance of convincing data indicating that promoting lifestyle changes, improving sleep hygiene, and adjusting diet can ameliorate both metabolic syndrome and OSAS, especially in obese patients. The incidence of OSAS in acromegaly is high, though GH treatments seem to be unrelated to the onset of apnea in GH-deficient individuals. Prospective studies have suggested an association between hypertension and OSAS because intermittent nocturnal hypoxia prompts an increase in sympathetic tone, endothelial dysfunction, and vascular inflammation: aldosterone excess may have a pathophysiological role, and some authors have reported that treating OSAS leads to a modest, but significant, reduction in blood pressure.