Challenges and strategies to combat resistance mechanisms in thyroid cancer therapeutics

BACKGROUND

BRAF V600E and K/N/H RAS mutations and oncogenic kinase fusions involving NTRK, RET, ALK and ROS1 have been identified as actionable targets in thyroid cancer. These driver alterations lead to onocogene addiction which has been successfully exploited through tyrosine kinase inhibitors. Acquired resistance may develop following an initial response requiring a therapeutic pivot to new therapies.

SUMMARY

Several pathways for development of acquired resistance have been identified. These encompass acquired on-target gene mutation impeding drug activity and upregulation of bypass kinase signaling pathways leading to tumour progression. Biopsy of resistant lesions (liquid or tissue) and subsequent molecular analysis can assist with new therapeutic strategies.

CONCLUSIONS

Progression-free survival is curtailed by developing acquired resistance. To minimise this therapeutic liability, clinicians must be anticipatory in identifying the drivers and characterising mechanisms of on target resistance.

The length of FOXE1 polyalanine tract in congenital hypothyroidism: Evidence for a pathogenic role from familial, molecular and cohort studies

INTRODUCTION

FOXE1 is required for thyroid function and its homozygous mutations cause a rare syndromic form of congenital hypothyroidism (CH). FOXE1 has a polymorphic polyalanine tract whose involvement in thyroid pathology is controversial. Starting from genetic studies in a CH family, we explored the functional role and involvement of FOXE1 variations in a large CH population.

METHODS

We applied NGS screening to a large CH family and a cohort of 1752 individuals and validated these results by in silico modeling and in vitro experiments.

RESULTS

A new heterozygous FOXE1 variant segregated with 14-Alanine tract homozygosity in 5 CH siblings with athyreosis. The p.L107V variant demonstrated to significantly reduce the FOXE1 transcriptional activity. The 14-Alanine-FOXE1 displayed altered subcellular localization and significantly impaired synergy with other transcription factors, when compared with the more common 16-Alanine-FOXE1. The CH group with thyroid dysgenesis was largely and significantly enriched with the 14-Alanine-FOXE1 homozygosity.

DISCUSSION

We provide new evidence that disentangle the pathophysiological role of FOXE1 polyalanine tract, thereby significantly broadening the perspective on the role of FOXE1 in the complex pathogenesis of CH. FOXE1 should be therefore added to the group of polyalanine disease-associated transcription factors.

A Case Report of Poor Response to Selpercatinib in the Presence of a 632_633 RET Deletion

Background: Genomic deletions in medullary thyroid cancer (MTC) are rare. Selpercatinib is a highly selective RET inhibitor for treatment of metastatic RET-altered MTC. We report a 35-year-old male with an aggressive metastatic MTC harboring p.632_633del RET that was poorly responsive to RET kinase inhibitor selpercatinib. Objective: Our objective was to understand the clinical phenotype of p.632_633del RET in MTC in the context of novel RET kinase inhibitor treatment. Methods: Wild-type and p.632_633del RET sequences were modeled using a lighter version of the AlphaFold2 (AF2) software. Functional studies were performed on transfected HEK 293 cells (pCMV6-Entry, pCMV6-RET, or pCMV6-RET(p.632_633del) treated with inhibitors for 24 hours and analyzed on luciferase assays. Results: Structural modeling revealed a paucity of disulfide bridge between Cys630-Cys634 in p.632_633del RET sequences, apparent in wild-type, while forming an intermolecular disulfide bridge between two Cys656. Proximity of juxtamembrane segments of each dimer may impede Tyr687 phosphorylation and stable conformation of intracellular RET that hosts selpercatinib. In vitro experiments confirmed a reduction in efficacy of selpercatinib upon p.632_633del RET compared with wild-type RET control. Conclusion: Clinical presentation together with structural modeling and functional studies suggests that p.632_633del RET results in poor response to selpercatinib.

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.

Polypharmacy With High Drug Burden Index (DBI) Alters the Gut Microbiome Overriding Aging Effects and Is Reversible With Deprescribing

Aging, medication use, and global function are associated with changes in the microbiome. However, their interrelationships and changes over time require further characterization. In a longitudinal aging mouse study, we investigated the effects of aging, chronic polypharmacy with a high Drug Burden Index (DBI, measure of total anticholinergic and sedative medication exposure) and gradual cessation (deprescribing) on the microbiome, further exploring any association with global outcomes. Chronic administration of high DBI polypharmacy attenuated the aging-related reduction in alpha diversity, which was not sustained after deprescribing. Beta diversity and LEfSe (Linear discriminant analysis Effect Size) features varied with age, polypharmacy, and deprescribing. Aging with and without polypharmacy shared decreases in Bifidobacteriaceae, Paraprevotellaceae, Bacteroidaceae, and Clostridiaceae, while only aging with polypharmacy showed increased LEfSe features. Microbiome diversity correlated with frailty, nesting, and open field performance. Polypharmacy deprescribing reversed changes that occurred with treatment. However, the microbiome did not recover to its pretreatment composition at 12 months, nor develop the same aging-related changes from 12 to 24 months as the control group. Overall, aging, chronic polypharmacy, and deprescribing differentially affected the diversity and composition of the gut microbiome, which is associated with frailty and function.

Specimen oriented intraoperative margin assessment in oral cavity and oropharyngeal squamous cell carcinoma

OBJECTIVE

Evaluate the oncologic outcomes and cost analysis of transitioning to a specimen oriented intraoperative margin assessment protocol from a tumour bed sampling protocol in oral cavity (OCSCC) and oropharyngeal squamous cell carcinoma (OPSCC).

STUDY DESIGN

Retrospective case series and subsequent prospective cohort study SETTING: Tertiary care academic teaching hospital SUBJECTS AND METHODS: Retrospective case series of all institutional T1-T2 OCSCC or OPSCC treated with primary surgery between January 1st 2009 - December 31st 2014. Kaplan-Meier survival estimates with log rank tests were used to compare patients based on final margin status. Cost analysis was performed for escalation of therapy due to positive final margins. Following introduction of a specimen derived margin protocol, successive prospective cohort study of T1-T4 OCSCC or OPSCC treated with primary surgery from January 1st 2017 - December 31st 2018. Analysis and comparison of both protocols included review of intraoperative margins, final pathology and treatment cost.

RESULTS

Analysis of our intra-operative tumour bed frozen section protocol revealed 15 of 116 (12.9%) patients had positive final pathology margins, resulting in post-operative escalation of therapy for 14/15 patients in the form of re-resection (7/14), radiation therapy (6/14) and chemoradiotherapy (1/14). One other patient with positive final margins received escalated therapy for additional negative prognostic factors. Recurrence free survival at 3 years was 88.4 and 50.7% for negative and positive final margins respectively (p = 0.048). Implementation of a specimen oriented frozen section protocol resulted in 1 of 111 patients (0.9%) having positive final pathology margins, a statistically significant decrease (p < 0.001). Utilizing our specimen oriented protocol, there was an absolute risk reduction for having a final positive margin of 12.0% and relative risk reduction of 93.0%. Estimated cost avoidance applying the specimen oriented protocol to our previous cohort was $412,052.812017 CAD.

CONCLUSION

Implementation of a specimen oriented intraoperative margin protocol provides a statistically significant decrease in final positive margins. This change in protocol leads to decreased patient morbidity by avoiding therapy escalation attributable only to positive margins, and avoids the economic costs of these treatments.

The Histamine 3 Receptor Is Expressed in the Heart and Its Activation Opposes Adverse Cardiac Remodeling in the Angiotensin II Mouse Model

Histamine is a basic amine stored in mast cells, with its release capable of activating one of four histamine receptors. The histamine 3 receptor (H3R) is known to be cardioprotective during acute ischemia by acting to limit norepinephrine release. However, a recent study reported that myofibroblasts isolated from the infarct zone of rat hearts responded to H3R activation by up-regulating collagen production. Thus, it is necessary to clarify the potential role of the H3R in relation to fibrosis in the heart. We identified that the mouse left ventricle (LV) expresses the H3R. Isolation of mouse cardiac fibroblasts determined that while angiotensin II (Ang II) increased levels of the H3R, these cells did not produce excess collagen in response to H3R activation. Using the Ang II mouse model of adverse cardiac remodeling, we found that while H3R blockade had little effect on cardiac fibrosis, activation of the H3R reduced cardiac fibrosis and macrophage infiltration. These findings suggest that when activated, the H3R is anti-inflammatory and anti-fibrotic in the mouse heart and may be a promising target for protecting against cardiac fibrosis.

The abscopal effect in head-and-neck squamous cell carcinoma treated with radiotherapy and nivolumab: a case report and literature review

Introduction

The abscopal effect is a rarely observed outcome of radiotherapy wherein there is a reduction in metastatic disease burden outside of the targeted treatment area. Likely due to an in situ vaccine effect of radiotherapy, the abscopal effect may be augmented by immunotherapy. This report is the first case of the abscopal effect observed in metastatic head-and-neck squamous cell carcinoma (hnscc) treated with concurrent radiotherapy and single-agent nivolumab.

Case Description

An otherwise healthy 57-year-old man underwent craniofacial resection and adjuvant chemoradiotherapy for advanced sinonasal squamous cell carcinoma. Distant metastatic disease developed shortly after primary treatment, and immunotherapy in the form of nivolumab was initiated. Subsequent oligometastatic progression despite immunotherapy prompted palliative radiotherapy to a single metastasis due to pending symptomatology. Post-radiotherapy, the abscopal effect was observed with all distant sites of metastatic disease shrinking. Five months following treatment, a sustained reduction in disease burden has been demonstrated.

Summary

We present the first case of the abscopal effect in a patient with metastatic hnscc treated with palliative radiotherapy concurrent with single-agent nivolumab immunotherapy, and only the third case of the abscopal effect in metastatic head-and-neck cancer. Dual treatment with immunotherapy and radiotherapy may be an important treatment option in the future, mediated through the abscopal effect.

Key MicroRNA's and Their Targetome in Adrenocortical Cancer

Adrenocortical Carcinoma (ACC) is a rare but aggressive malignancy with poor prognosis and limited response to available systemic therapies. Although complete surgical resection gives the best chance for long-term survival, ACC has a two-year recurrence rate of 50%, which poses a therapeutic challenge. High throughput analyses focused on characterizing the molecular signature of ACC have revealed specific micro-RNAs (miRNAs) that are associated with aggressive tumor phenotypes. MiRNAs are small non-coding RNA molecules that regulate gene expression by inhibiting mRNA translation or degrading mRNA transcripts and have been generally implicated in carcinogenesis. This review summarizes the current insights into dysregulated miRNAs in ACC tumorigenesis, their known functions, and specific targetomes. In addition, we explore the possibility of particular miRNAs to be exploited as clinical biomarkers in ACC and as potential therapeutics.

Congenital Hypoparathyroidism Associated With Elevated Circulating Nonfunctional Parathyroid Hormone Due to Novel PTH Mutation

CONTEXT

Familial hypoparathyroidism has a heterogeneous presentation where patients usually have low parathyroid hormone (PTH) levels due to impaired production or secretion. This contrasts with pseudohypoparathyroidism, in which PTH resistance is usually associated with an elevated serum PTH. High levels of circulating PTH can also be due to bioinactive PTH, which is difficult to distinguish from pseudohypoparathyroidism on biochemical grounds.

CASE DESCRIPTION

We report on 2 sisters from consanguineous parents who presented with tetany at birth and were diagnosed with congenital hypocalcemia. Serum PTH levels were normal for many years, but progressively increased in midadulthood to greater than 100x the upper limit of normal on multiple assays. Homozygosity mapping was performed on 1 sister that demonstrated loss of heterozygosity (LOH) around PTH. Sequencing revealed a previously unreported variant, c.94T>C, predicting a codon change of p.Ser32Pro that is biologically inactive.

CONCLUSIONS

This case report shows a previously unreported unusual biochemical phenotype of a rising PTH in the context of a novel PTH mutation. This expands the evolving genotypes associated with hypoparathyroidism without established gene mutations.

ETS Factor ETV5 Activates the Mutant Telomerase Reverse Transcriptase Promoter in Thyroid Cancer

Background: Co-occurrence of TERT (telomerase reverse transcriptase) promoter (TERTp) mutations with BRAF/RAS mutations is associated with significantly more aggressive thyroid cancer. TERTp mutations are hypothesized to generate de novo binding sites for ETS transcription factors, which are themselves activated by BRAF/RAS-stimulated MEK-ERK activity. To date, a detailed study of this mechanism has been limited to only a few cancer types, and we hypothesized that ETS factors involved in TERTp activation could vary between different cancers. Methodology: Here we sought to identify ETS factor(s) required for TERTp activation in thyroid cancer, using a combination of in silico analyses of TCGA data, and experimentation using in vitro thyroid cell models analyzed by quantitative reverse transcription-PCR, immunoprecipitation (IP), chromatin IP, and gene reporter assays. Results: We found that ETV5 was abundantly expressed in papillary thyroid cancers from the TCGA data set, and in thyroid cancer cell line models. Furthermore, ETV5 was found to preferentially bind to the -124 bp(T) TERTp allele and stimulate TERT transcription in thyroid cancer cells devoid of GA binding protein transcription factor (GABP) activity. We also found that ETV5 functionally cooperates with the transcription factor FOXE1 to further enhance TERTp activity, a mechanism that may at least partially explain why FOXE1 represents a significant genetic determinant of thyroid cancer risk. Conclusions: ETS factors that activate mutant TERTp vary between cancer types, and here we show for the first time that ETV5 demonstrates mutant allele-specific affinity for TERTp in thyroid cancer, a property that has previously only been attributable to GABP.

An InDel in Phospholipase-C-B-1 Is Linked with Euthyroid Multinodular Goiter

BACKGROUND

Euthyroid multinodular goiter (MNG) is common, but little is known about the genetic variations conferring predisposition. Previously, a family with MNG of adolescent onset was reported in which some family members developed papillary thyroid carcinomas (PTC).

METHODS

Genome-wide linkage analysis and next-generation sequencing were conducted to identify genetic variants that may confer disease predisposition. A multipoint nonparametric LOD score of 3.01 was obtained, covering 19 cM on chromosome 20p. Haplotype analysis reduced the region of interest to 10 cM.

RESULTS

Analysis of copy number variation identified an intronic InDel (∼1000 bp) in the PLCB1 gene in all eight affected family members and carriers (an unaffected person who has inherited the genetic trait). This InDel is present in approximately 1% of "healthy" Caucasians. Next-generation sequencing of the region identified no additional disease-associated variant, suggesting a possible role of the InDel. Since PLCB1 contributes to thyrocyte growth regulation, the InDel was investigated in relevant Caucasian cohorts. It was detected in 0/70 PTC but 4/81 unrelated subjects with MNG (three females; age at thyroidectomy 27-59 years; no family history of MNG/PTC). The InDel frequency is significantly higher in MNG subjects compared to controls (χ² = 5.076; p = 0.024. PLCB1 transcript levels were significantly higher in thyroids with the InDel than without (p < 0.02).

CONCLUSIONS

The intronic PLCB1 InDel is the first variant found in familial multiple papilloid adenomata-type MNG and in a subset of patients with sporadic MNG. It may function through overexpression, and increased PLC activity has been reported in thyroid neoplasms. The potential role of the deletion as a biomarker to identify MNG patients more likely to progress to PTC merits exploration.

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.

Laryngeal recurrence sites in patients previously treated with transoral laser microsurgery for squamous cell carcinoma

BACKGROUND

The laryngeal framework provides a natural barrier preventing tumour spread to extralaryngeal structures. Transoral laser microsurgery (TLM) for laryngeal squamous cell carcinoma (SCC) may violate these boundaries, altering the pathways of tumor spread for potential recurrences. Our project objective is to describe laryngeal SCC recurrence patterns and overall survival in patients requiring total laryngectomy (TL) after TLM.

METHODS

Patients undergoing TLM for laryngeal SCC requiring salvage TL were identified from a prospective CO2 laser database containing all patients undergoing TLM for head and neck malignancies at the QEII Health Sciences Center in Halifax, Nova Scotia between March 2002 - May 2014. Surgical pathology reports were analyzed for tumor characteristics, extent of recurrence and invasion of local structures. Kaplan-Meier analyses were performed to evaluate overall survival, disease specific survival (DSS) and locoregional control.

RESULTS

Fifteen patients were identified from the database as receiving salvage TL for recurrent disease after initial TLM resection for laryngeal SCC. Final pathology reports demonstrated that 67% (10/15) of patients had thyroid cartilage involvement while 53% (9/15) of patients had cricoid cartilage involvement on salvage TL pathology. 33% (5/15) of patients had perineural invasion and 27% (4/15) had lymphovascular invasion. Mean and median follow-up times were 36.7 months and 26.8 months respectively (range 3.9-112.6). The Kaplan-Meier estimate for overall survival at 36 months was 40% post TL with a standard error (SE) of 13.6%. DSS was 47% (SE 14.2%), and locoregional control was 55% (SE 14.5%) post TL.

CONCLUSIONS

Laryngeal recurrence sites following TLM seem to be consistent with historical data at known laryngeal sites of vulnerability. Treatment with TLM does not predispose patients to a lower rate of locoregional control and overall survival after total laryngectomy and salvage outcomes are consistent with literature values.

TERT promoter mutations are a major indicator of recurrence and death due to papillary thyroid carcinomas

CONTEXT

TERT promoter mutations have been associated with adverse prognosis in papillary thyroid carcinomas (PTCs).

OBJECTIVE

We investigated the association between TERT promoter mutations and survival from PTC.

DESIGN

Retrospective observational cohort study.

PATIENTS

Eighty consecutive patients with PTC who underwent surgery between 1990 and 2003.

MEASUREMENTS

TERT promoter was genotyped in DNA from 80 archival PTCs by Sanger sequencing. Median follow-up was 106 months (range 1-270). Outcomes analysis was stratified according to disease and overall survival status. For each parameter, relative risk (RR) adjusted for age at first surgery and gender was estimated. Both univariate and multivariate analyses were performed using logistic regression, Kaplan-Meier survival analysis and Cox regression models.

RESULTS

PTCs from 11 patients (14%) contained either C228T or C250T TERT promoter mutation. TERT mutations were significantly associated with adverse prognostic features such as older age (P = 0·002), male gender (P = 0·01) and Stage IV disease (P = 0·03). Four patients died from PTC during follow-up: 3 patients with TERT mutations (27%) and one without (1·5%). Disease-related mortality rate with or without TERT mutations was 33·7 vs 1·6 per 1000 patient-years respectively, that is 10 (95% CI = 1·0-104·1, P = 0·05) fold higher, after adjustment for age at first surgery and gender. The combination of TERT promoter mutation and BRAF(V) (600E) significantly increased disease-related death risk (P = 0·002). TERT mutations increased expression of a reporter gene in thyroid cells containing BRAF(V) (600E) .

CONCLUSIONS

TERT promoter mutations are a major indicator of death due to PTCs. Conversely, absence of TERT mutations portends better survival.

FOXO factors and breast cancer: outfoxing endocrine resistance

The majority of metastatic breast cancers cannot be cured and present a major public health problem worldwide. Approximately 70% of breast cancers express the estrogen receptor, and endocrine-based therapies have significantly improved patient outcomes. However, the development of endocrine resistance is extremely common. Understanding the molecular pathways that regulate the hormone sensitivity of breast cancer cells is important to improving the efficacy of endocrine therapy. It is becoming clearer that the PI3K-AKT-forkhead box O (FOXO) signaling axis is a key player in the hormone-independent growth of many breast cancers. Constitutive PI3K-AKT pathway activation, a driver of breast cancer growth, causes down-regulation of FOXO tumor suppressor functions. This review will summarize what is currently known about the role of FOXOs in endocrine-resistance mechanisms. It will also suggest potential therapeutic strategies for the restoration of normal FOXO transcriptional activity.

DNA Methylation Analysis: Choosing the Right Method

In the burgeoning field of epigenetics, there are several methods available to determine the methylation status of DNA samples. However, choosing the method that is best suited to answering a particular biological question still proves to be a difficult task. This review aims to provide biologists, particularly those new to the field of epigenetics, with a simple algorithm to help guide them in the selection of the most appropriate assay to meet their research needs. First of all, we have separated all methods into two categories: those that are used for: (1) the discovery of unknown epigenetic changes; and (2) the assessment of DNA methylation within particular regulatory regions/genes of interest. The techniques are then scrutinized and ranked according to their robustness, high throughput capabilities and cost. This review includes the majority of methods available to date, but with a particular focus on commercially available kits or other simple and straightforward solutions that have proven to be useful.

Destabilizing RET in targeted treatment of thyroid cancers

Metastatic differentiated thyroid cancers (DTC) are resistant to traditional chemotherapy. Kinase inhibitors have shown promise in patients with progressive DTC, but dose-limiting toxicity is commonplace. HSP90 regulates protein degradation of several growth-mediating kinases such as RET, and we hypothesized that HSP90 inhibitor (AUY922) could inhibit RET-mediated medullary thyroid cancer (MTC) as well as papillary thyroid cancer (PTC) cell growth and also radioactive iodine uptake by PTC cells. Studies utilized MTC cell lines TT (C634W) and MZ-CRC-1 (M918T) and the PTC cell line TPC-1 (RET/PTC1). Cell viability was assessed with MTS assays and apoptosis by flow cytometry. Signaling target expression was determined by western blot and radioiodine uptake measured with a gamma counter. Prolonged treatment of both MTC cell lines with AUY922 simultaneously inhibited both MAPK and mTOR pathways and significantly induced apoptosis (58.7 and 78.7% reduction in MZ-CRC-1 and TT live cells respectively, following 1 μM AUY922; P<0.02). Similarly in the PTC cell line, growth and signaling targets were inhibited, and also a 2.84-fold increase in radioiodine uptake was observed following AUY922 administration (P=0.015). AUY922 demonstrates in vitro activity against MTC and PTC cell lines. We observed a potent dose-dependent increase in apoptosis in MTC cell lines following drug administration confirming its anti-tumorigenic effects. Western blots confirm inhibition of pro-survival proteins including AKT suggesting this as the mechanism of cell death. In a functional study, we observed an increase in radioiodine uptake in the PTC cell line following AUY922 treatment. We believe HSP90 inhibition could be a viable alternative for treatment of RET-driven chemo-resistant thyroid cancers.

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.

Utilization of a MAB for BRAF(V600E) detection in papillary thyroid carcinoma

Identification of BRAF(V600E) in thyroid neoplasia may be useful because it is specific for malignancy, connotes a worse prognosis, and is the target of novel therapies currently under investigation. Sanger sequencing is the 'gold standard' for mutation detection but is subject to sampling error and requires resources beyond many diagnostic pathology laboratories. In this study, we compared immunohistochemistry (IHC) using a BRAF(V600E) mutation-specific MAB to Sanger sequencing on DNA from formalin-fixed paraffin-embedded tissue, in a well-characterized cohort of 101 papillary thyroid carcinoma (PTC) patients. For all cases, an IHC result was available; however, five cases failed Sanger sequencing. Of the 96 cases with molecular data, 68 (71%) were BRAF(V600E) positive by IHC and 59 (61%) were BRAF(V600E) positive by sequencing. Eleven cases were discordant. One case was negative by IHC and initially positive by sequencing. Repeat sequencing of that sample and sequencing of a macrodissected sample were negative for BRAF(V600E). Of ten cases positive by IHC but negative by sequencing on whole sections, repeat sequencing on macrodissected tissue confirmed the IHC result in seven cases (suggesting that these were false negatives of sequencing on whole sections). In three cases, repeat sequencing on recut tissue remained negative (including using massive parallel sequencing), but these cases demonstrated relatively low neoplastic cellularity. We conclude that IHC for BRAF(V600E) is more sensitive and specific than Sanger sequencing in the routine diagnostic setting and may represent the new gold standard for detection of BRAF(V600E) mutation in PTC.

Association of FOXE1 polyalanine repeat region with papillary thyroid cancer

CONTEXT

Polyalanine tract variations in transcription factors have been identified for a wide spectrum of developmental disorders. The thyroid transcription factor forkhead factor E1 (FOXE1) contains a polymorphic polyalanine tract with 12-22 alanines. Single-nucleotide polymorphisms (SNP) close to this locus are associated with papillary thyroid cancer (PTC), and a strong linkage disequilibrium block extends across this region.

OBJECTIVE

The objective of the study was to assess whether the FOXE1 polyalanine repeat region was associated with PTC and to assess the effect of polyalanine repeat region variants on protein expression, DNA binding, and transcriptional function on FOXE1-responsive promoters.

DESIGN

This was a case-control study.

SETTING

The study was conducted at a tertiary referral hospital.

PATIENTS AND METHODS

The FOXE1 polyalanine repeat region and tag SNP were genotyped in 70 PTC, with a replication in a further 92 PTC, and compared with genotypes in 5767 healthy controls (including 5667 samples from the Wellcome Trust Case Control Consortium). In vitro studies were performed to examine the protein expression, DNA binding, and transcriptional function for FOXE1 variants of different polyalanine tract lengths.

RESULTS

All the genotyped SNP were in tight linkage disequilibrium, including the FOXE1 polyalanine repeat region. We confirmed the strong association of rs1867277 with PTC (overall P = 1 × 10(-7), odds ratio 1.84, confidence interval 1.31-2.57). rs1867277 was in tight linkage disequilibrium with the FOXE1 polyalanine repeat region (r(2) = 0.95). FOXE1(16Ala) was associated with PTC with an odds ratio of 2.23 (confidence interval 1.42-3.50; P = 0.0005). Functional studies in vitro showed that FOXE1(16Ala) was transcriptionally impaired compared with FOXE1(14Ala), which was not due to differences in protein expression or DNA binding.

CONCLUSIONS

We have confirmed the previous association of FOXE1 with PTC. Our data suggest that the coding polyalanine expansion in FOXE1 may be responsible for the observed association between FOXE1 and PTC.

Multikinase inhibitors: a new option for the treatment of thyroid cancer

Thyroid cancer typically has a good outcome following standard treatments, which include surgery, radioactive iodine ablation and treatment with TSH-suppressive levothyroxine. Thyroid cancers that persist or recur following these therapies have a poorer prognosis. Activation of mitogenic and angiogenic signaling pathways occurs in these cancers, and preclinical models have shown that inhibition of key kinase steps in these pathways can have antitumoral effects. Several of these kinase inhibitors have now been tested in phase II and phase III trials, with modestly encouraging results. Some promising data exist for the use of vandetanib (also known as ZD6474), motesanib, axitinib, cabozantinib (also known as XL184), sorafenib, sunitinib, pazopanib and lenvatinib (also known as E7080) in progressive thyroid cancer of medullary, papillary and follicular subtypes. These drugs are generally well-tolerated, although dose-limiting toxicities are common, and a few (probable) treatment-related deaths have been reported. Additional phase III trials will be needed to conclusively show that treatment benefit exceeds risk. Drug resistance can occur via activation of alternate mitogenic signals (pathway switching), as has been reported for the use of kinase inhibitors in other malignancies, such as melanoma. The hypothesis that combinations of kinase inhibitors targeting different pathways might produce better results is currently being tested in several clinical trials.

Contribution of a common variant in the promoter of the 1-α-hydroxylase gene (CYP27B1) to fracture risk in the elderly

CYP27B1 encodes mitochondrial 1α-hydroxylase, which converts 25-hydroxyvitamin D to its active 1,25-dihydroxylated metabolite. We tested the hypothesis that common variants in the CYP27B1 promoter are associated with fracture risk. The study was designed as a population-based genetic association study, which involved 153 men and 596 women aged 65-101 years, who had been followed for 2.2 years (range 0.1-5.5) between 1999 and 2006. During the follow-up period, the incidence of fragility fractures was ascertained. Bone ultrasound attenuation (BUA) was measured in all individuals, as were serum 25-hydroxyvitamin D and PTH concentrations; 86% subjects had vitamin D insufficiency. Genotypes were determined for the -1260C>A (rs10877012) and +2838T>C (rs4646536) CYP27B1 polymorphisms. A reporter gene assay was used to assess functional expression of the -1260C>A CYP27B1 variants. The association between genotypes and fracture risk was analyzed by Cox's proportional hazards model. We found that genotypic distribution of CYP27B1 -1260 and CYP27B1 +2838 polymorphisms was consistent with the Hardy-Weinberg equilibrium law. The two polymorphisms were in high linkage disequilibrium, with D' = 0.96 and r² = 0.94. Each C allele of the CYP27B1 -1260 polymorphism was associated with increased risk of fracture (hazard ratio = 1.34, 95% CI 1.03-1.73), after adjustment for age, sex, number of falls, and BUA. In transient transfection studies, a reporter gene downstream of the -1260(A)-containing promoter was more highly expressed than that containing the C allele. These data suggest that a common but functional variation within the CYP27B1 promoter gene is associated with fracture risk in the elderly.

BRAF(V600E) mutation is associated with an increased risk of nodal recurrence requiring reoperative surgery in patients with papillary thyroid cancer

BACKGROUND

The role of the B-isoform of the Raf kinase (BRAF) mutation BRAF(V600E) as an independent prognostic factor in papillary thyroid cancer (PTC) remains controversial. Some studies suggest that tumors containing BRAF(V600E) have decreased radioiodine avidity and present a greater risk of nodal recurrence and distant metastases.

METHODS

Paraffin-embedded specimens from consecutive patients who underwent surgery for PTC before 2003 were independently reviewed by an endocrine pathologist. DNA was extracted, amplified by polymerase chain reaction, and the presence of the BRAF(V600E) mutation was determined by restriction digest. Tumor characteristics and long-term disease outcomes were analyzed according to BRAF(V600E) status.

RESULTS

BRAF(V600E) was identified in 60 (59%) of 101 patients. At a median follow-up of 106 months, the overall disease-free survival was 78%. Clinically evident nodal recurrence occurred in 11% of BRAF(V600E)-positive patients, and all patients required lateral neck dissection (P = .02). In contrast, subclinical nodal recurrence occurred in 7% of BRAF(V600E)-negative patients, and all recurrences were successfully ablated with radioactive iodine. There was a trend toward poorer disease-free survival among patients with stage III/IV PTC and BRAF(V600E) mutation (P = .08). All 5 disease-related deaths occurred in patients with BRAF(V600E)-positive primary tumors (P = .06).

CONCLUSION

The BRAF(V600E) mutation in PTC is associated with an increased risk of palpable nodal recurrence and the need for reoperative surgery.

Altered Tear Composition in Smokers and Patients With Graves Ophthalmopathy

OBJECTIVES

To analyze, compare, and contrast tear composition in healthy nonsmokers, smokers who were otherwise healthy, and patients with Graves disease (GD) accompanied by Graves ophthalmopathy (GO) of varying severity.

METHODS

Reflex tears were collected using Schirmer strips from 37 healthy nonsmokers, 33 otherwise healthy smokers, 51 patients with GD, and 85 patients with GO. Thyrotropin receptor-stimulating activity and serum thyroid-stimulating antibodies were measured. Pooled tear samples from healthy nonsmokers, healthy smokers, and patients with GO were separated by means of electrophoresis. Proteins expressed in healthy smokers, patients with GO, and healthy nonsmokers were separated by means of electrophoresis and analyzed by mass spectrometry.

RESULTS

Based on the 97th percentile of findings from healthy nonsmokers, specific thyrotropin receptor-stimulating activity was detected in 25% of the tear samples from healthy smokers, 32% of those from patients with GD, and 41% of those from patients with GO. Clinical activity scores correlated with serum thyroid-stimulating antibody levels but not tear thyrotropin receptor-stimulating activity. Electrophoresis revealed additional proteins of 30 to 41 kDa in the tear samples from patients with GO and healthy smokers compared with samples from healthy nonsmokers. These proteins were identified as zinc-alpha2-glycoprotein and lactoferrin but have no thyrotropin receptor-stimulating activity.

CONCLUSIONS

We demonstrate similar changes in tear composition in patients with GO and healthy smokers compared with healthy nonsmokers. Expression of zinc-alpha2-glycoprotein and lactoferrin is increased and their molecular weights are modified, suggesting degradation and/or changes during glycosylation, which may affect the bioactivities of zinc-alpha2-glycoprotein and lactoferrin. Clinical Relevance Smoking, which is a significant risk factor for the development of GO, modifies tear composition.

Anaesthetic assistants: their role in the development and resolution of anaesthetic incidents

Trained anaesthetic assistants are considered essential for the safe conduct of anaesthesia. Data from 5837 AIMS (Anaesthetic Incident Monitoring Study) reports were evaluated for issues concerning anaesthetic assistants in the generation and resolution of anaesthetic incidents. "Inadequate assistance" as a contributing factor was identified in 187 reports, whilst "skilled assistance" which minimized the incident was present in 808 cases. One hundred and seventy-two reports specifically commented on anaesthetic assistants in the narrative section of the AIMS form. All surgical specialties were represented. In 147 of these reports the assistant actually contributed to or failed to assist with the incident. Although the majority of outcomes from the reports were uneventful, prolonged stay, awareness and ICU admission did ensue in a small number of cases. The most common incidents were related to problems with equipment, communication and inadequate staffing levels (number and/or skill mix). Results from this study have implications for anaesthetic assistant staffing levels and the orientation of course content.

Reiki: a complementary therapy for life

Tom was diagnosed with a very aggressive cancer and received only palliative radiation and medication. At the time of diagnosis, his symptoms suggested that he had a very limited life expectancy. With the Reiki and his intent, he was able to achieve his goal of long-term stability with freedom from immobilizing pain and swelling. Tom's comfort and quality of life improved dramatically, and he is living well with his cancer. Reiki has been associated with dramatic results for many patients. The importance of the patient's intent during Reiki treatments cannot be overemphasized. Some general trends seen with Reiki include: periods of stabilization in which there is time to enjoy the last days of one's life; a peaceful and calm passing if death is imminent; and relief from pain, anxiety, dyspnea and edema. Reiki is a valuable complement in supporting patients in their end-of-life journey, enhancing the quality of their remaining days.

Research to optimise human performance

The need for greater understanding of the factors which limit human movement and functional capacity and for determining effective methods for ensuring optimum performance has led to a wide range of related research studies. This paper draws on some of the research projects pursued or supervised by the author, to show the knowledge gained in aspects of movement capacity, muscle function and the influence of sensory motor deficits on movement and function. The inter-relationship of the many factors influencing functional capacity emphasise the need to think broadly in research. Studies of effectiveness of physiotherapy and collection of data for ergonomic workplace design highlight the importance of both prevention and therapeutic care and demonstrate the contributions which physiotherapists can make through research to optimise human performance.

Suppression of human peripheral blood mononuclear cell function by methadone and morphine

Recent studies have shown that in vitro exposure of peripheral blood mononuclear cells (PBMC) to morphine results in suppressed respiratory-burst activity of monocytes and impaired interferon-gamma (IFN-gamma) production by lymphocytes. To investigate the potential in vivo effect of an opiate on these cell functions, PBMC were obtained from patients maintained on methadone. These freshly isolated mononuclear cells had a significantly impaired capacity to generate superoxide anion (O2-) in response to phorbol myristate acetate (PMA), while production of IFN-gamma by concanavalin A-stimulated cells was intact. After cell culture for 48 h, the defective O2- generating capacity was sustained. Also, culturing PBMC from healthy controls in the presence of methadone or morphine at concentrations as low as 10(-12) M caused significant suppression of PMA-stimulated O2- release. Because reactive oxygen intermediates produced by PBMC may participate in host defense against opportunistic pathogens in AIDS, these results underscore the need for investigations of the biological consequences of opiate-mediated immunosuppression.

Development of a health questionnaire specific for end-stage renal disease

To compare the efficacy of various end-stage renal disease (ESRD) therapies valid and reproducible probes which measure well-being and are specific for ESRD are necessary. Four studies were undertaken to provide and test these probes. (1) 107 dialysis and 119 transplant recipients were interviewed to determine the prevalence of 24 physical symptoms. (2) A questionnaire was devised using 2 new indexes (a symptom scale derived from the first study using 12 symptoms and an affect scale comprising 12 emotions) and 6 indexes previously used in other chronic illnesses. Interobserver and intraobserver reproducibility was satisfactory. (3) Construct validity for the questionnaire was shown by interviewing 97 dialysis and 82 transplant patients in whom we hypothesized that physical well-being would be better in transplant patients. After age matching the transplant group was more active, with a higher objective quality of life and fewer physical symptoms than the dialysis group. (4) 63 stable dialysis, 67 stable transplant, 15 dialysis patients successfully transplanted in the intervening year and 5 failed transplanted patients were reinterviewed 1 year later to assess the responsiveness of the questionnaire. In the group who had recently been successfully transplanted both physical, affect and quality of life scores showed a major improvement following transplant. We conclude that this questionnaire is specific for ESRD, examines physical, psychological, and social well-being, is brief, easily administered, reproducible, has construct validity and is responsive to changes in therapy.

The development of volitional behavior in the toddler years

In order to generate a description of early volitional skills, toddlers' abilities to match their activities to externally defined task standards and to monitor and control activities with respect to outcomes were studied. Children between 15 and 35 months were observed as they engaged in a series of play and clean-up tasks. The results showed that there is a consistent developmental pattern in the extent to which children focus on producing outcomes (rather than on acting for its own sake), the extent to which they monitor, correct, and control activities, and the frequency with which they react to their outcomes with positive affect. These patterns are interpreted in terms of changes in the representation of actions, self-regulation abilities, and the active involvement of the self in actions.

Clinical features and severity of nonspecific symptoms in dialysis patients

Nonspecific symptoms are common in dialysis patients but few methods are available to measure their severity and their response to alteration in dialysis therapy. To determine the clinical features and measure the severity of the most important symptoms in end-stage renal disease (ESRD) patients, 97 dialysis patients were interviewed, 63 of whom were reinterviewed 1 year later. For comparison 82 transplant recipients were also interviewed. The six most important symptoms in dialysis patients (using the product of the patient's perception of severity and prevalence) were tiredness, cramps, pruritus, dyspnea, headaches and joint pain. The symptoms were long-standing, occurred frequently, with little difference in prevalence between hemo- and peritoneal dialysis patients, and were often unrelated to a hemodialysis session. For each symptom, several dimensions of severity were assessed including frequency, duration, effect on sleep, daily living, activity, subjective quality of life and necessity for drug therapy. Often these dimensions did not correlate with patient's perception of severity. For each symptom these items were combined to give an aggregate score with a range 0-10. Interobserver reproducibility for each symptom score was greater than or equal to 0.7 but intraobserver reproducibility was poor for 3 symptoms, because of the fluctuating nature of the symptoms. Construct validity was demonstrated by finding a significantly worse distribution of aggregate scores for tiredness, cramps, pruritus, dyspnea and nausea/vomiting in dialysis compared to transplant patients. Aggregate scores changed little after 1 year's follow-up in stable dialysis patients but significant improvement in the aggregate scores for tiredness, dyspnea and nausea/vomiting were observed in 14 patients after successful transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)