New treatment modalities in advanced thyroid cancer

Thyroid functional and molecular imaging

Radioiodine uptake (RAIU) test with iodine-123 (Na[¹²³I]I) or iodine-131 (Na[¹³¹I]I) enables accurate evaluation and quantification of iodine uptake and kinetics within thyroid cells. Thyroid Scintigraphy (TS) employing Na[¹²³I]I or ^99mTc-pertechnetate (Na[^99mTc]TcO₄) provides information regarding the function and topographical distribution of thyroid cells activity, including detection and localization of ectopic thyroid tissue. Destructive thyrotoxicosis is characterized by low RAIU with scintigraphically reduced radiotracer activity in the thyroid tissue, while productive thyrotoxicosis (i.e. hyperthyroidism "stricto sensu") is characterized by high RAIU with scintigraphically diffuse (i.e. Graves' Disease, GD and diffuse thyroid autonomy) or focal (i.e. autonomously functioning thyroid nodules, AFTN) overactivity. Accordingly, RAIU and/or TS are widely used to differentiate different causes of thyrotoxicosis. In addition, several radiopharmaceuticals are also available to help differentiate benign from malignant thyroid nodules and inform clinical decision-making: scintigraphic identification of AFTNs obviate fine-needle aspiration (FNA) biopsy, and [^99mTc]Tc-hexakis-(2‑methoxy-2-isobutyl isonitrile ([^99mTc]Tc-MIBI) and/or ¹⁸F-fluoro-d-glucose ([¹⁸F]FDG) may complement the work-up of cytologically indeterminate "cold" nodules for reducing the need for diagnostic lobectomies/thyroidectomies. Finally, RAIU studies are also useful for calculating the administered therapeutic activity of Na[¹³¹I]I to treat hyperthyroidism and euthyroid multinodular goiter. All considered, thyroid molecular imaging allows functional characterization of different thyroid diseases, even before clinical symptoms become manifest, and remains integral to the management of such conditions. Our present paper summarizes basic concepts, clinical applications, and potential developments of thyroid molecular imaging in patients affected by thyrotoxicosis and thyroid nodules.

Identification of DPP4/CTNNB1/MET as a Theranostic Signature of Thyroid Cancer and Evaluation of the Therapeutic Potential of Sitagliptin

Simple Summary

In recent years, the incidence of thyroid cancer has been increasing globally, with papillary thyroid cancer (PTCa) being the most prevalent pathological type. Although PTCa has been regarded to be slow growing and has a good prognosis, in some cases, PTCa can be aggressive and progress despite surgery and radioactive iodine treatment. Therefore, searching for new targets and therapies is required. We utilized bioinformatics analyses to identify critical theranostic markers for PTCa. We found that DPP4/CTNNB1/MET is an oncogenic signature that is overexpressed in PTCa and associated with disease progression, distant metastasis, treatment resistance, immuno-evasive phenotypes, and poor clinical outcomes. Interestingly, our in silico molecular docking results revealed that sitagliptin, an antidiabetic drug, has strong affinities and potential for targeting DPP4/CTNNB1/MET signatures, even higher than standard inhibitors of these genes. Collectively, our findings suggest that sitagliptin could be repurposed for treating PTCa.

Abstract

In recent years, the incidence of thyroid cancer has been increasing globally, with papillary thyroid cancer (PTCa) being the most prevalent pathological type, accounting for approximately 80% of all cases. Although PTCa has been regarded to be slow growing and has a good prognosis, in some cases, PTCa can be aggressive and progress despite surgery and radioactive iodine treatment. In addition, most cancer treatment drugs have been shown to be cytotoxic and nonspecific to cancer cells, as they also affect normal cells and consequently cause harm to the body. Therefore, searching for new targets and therapies is required. Herein, we explored a bioinformatics analysis to identify important theranostic markers for THCA. Interestingly, we identified that the DPP4/CTNNB1/MET gene signature was overexpressed in PTCa, which, according to our analysis, is associated with immuno-invasive phenotypes, cancer progression, metastasis, resistance, and unfavorable clinical outcomes of thyroid cancer cohorts. Since most cancer drugs were shown to exhibit cytotoxicity and to be nonspecific, herein, we evaluated the anticancer effects of the antidiabetic drug sitagliptin, which was recently shown to possess anticancer activities, and is well tolerated and effective. Interestingly, our in silico molecular docking results exhibited putative binding affinities of sitagliptin with DPP4/CTNNB1/MET signatures, even higher than standard inhibitors of these genes. This suggests that sitagliptin is a potential THCA therapeutic, worthy of further investigation both in vitro and in vivo and in clinical settings.

Artesunate inhibits cell proliferation, migration, and invasion of thyroid cancer by regulating the PI3K/AKT/FKHR pathway

This study characterized the effects of artesunate on thyroid cancer and partially identified its related molecular mechanism. We determined the effect of artesunate on the proliferation of thyroid cancer cells using the MTT assay, cell colony formation experiments, and western blotting, and used flow cytometry to detect the apoptosis of cancer cells. Using a wound-healing assay, Transwell chamber experiments, and western blotting, we determined the effect of artesunate on cancer cell migration. By co-cultivating artesunate with the PI3K agonist, 740Y-P, we also partially identified the molecular mechanism. Artesunate significantly inhibited the growth, proliferation, migration, and invasion of thyroid cancer cells, and promoted the apoptosis of cancer cells. Using co-cultivation with a PI3K agonist, we found that the inhibitory effect of artesunate on cancer cells was mainly due to suppressing the PI3K/AKT/FKHR signaling pathway. By inhibiting the PI3K/AKT/FKHR signaling pathway, artesunate induced apoptosis of thyroid cancer cells and inhibited their proliferation and migration.

Synergy of GSK-J4 With Doxorubicin in KRAS-Mutant Anaplastic Thyroid Cancer

Background

Anaplastic thyroid cancer is the most aggressive thyroid cancer and has a poor prognosis. At present, there is no effective treatment for it.

Methods

Here, we used different concentrations of GSK-J4 or a combination of GSK-J4 and doxorubicin to treat human Cal-62, 8505C, and 8305C anaplastic thyroid cancer (ATC) cell lines. The in vitro experiments were performed using cell viability assays, cell cycle assays, annexin-V/PI binding assays, Transwell migration assays, and wound-healing assays. Tumor xenograft models were used to observe effects in vivo.

Results

The half maximal inhibitory concentration (IC50) of GSK-J4 in Cal-62 cells was 1.502 μM, and as the dose of GSK-J4 increased, more ATC cells were blocked in the G2-M and S stage. The combination of GSK-J4 and doxorubicin significantly increased the inhibitory effect on proliferation, especially in KRAS-mutant ATC cells in vivo (inhibition rate 38.0%) and in vitro (suppresses rate Fa value 0.624, CI value 0.673). The invasion and migration abilities of the KRAS-mutant cell line were inhibited at a low concentration (p < 0.05).

Conclusions

The combination of GSK-J4 with doxorubicin in KRAS-mutant ATC achieved tumor-suppressive effects at a low dose. The synergy of the combination of GSK-J4 and doxorubicin may make it an effective chemotherapy regimen for KRAS-mutant ATC.

Downregulating integrin subunit alpha 7 (ITGA7) promotes proliferation, invasion, and migration of papillary thyroid carcinoma cells through regulating epithelial-to-mesenchymal transition

Thyroid cancer is one of the common malignancies of the endocrine system and the number of thyroid cancer cases is increasing constantly. Significant work has focused on the molecular mechanisms of thyroid cancer, but many mechanisms remain undiscovered. In this study, we employed a comprehensive analysis of whole-transcriptome resequencing derived from paired papillary thyroid cancer (PTC) and normal thyroid tissues. We performed a massive parallel whole-transcriptome resequencing of matched PTC and normal thyroid tissues in 19 patients and found that integrin subunit alpha 7 (ITGA7) was downregulated in thyroid tumor tissues, but the function of ITGA7 in this cancer is still unclear. We also discovered that ITGA7 gene in thyroid cancer tissues was downregulated compared to paired adjacent non-tumor tissues by real-time quantitative polymerase chain reaction. After transfection with small interfering RNA to knock down ITGA7, the abilities of colony formation, proliferation, migration, and invasion were enhanced in PTC cell lines (TPC1 and KTC-1). Meanwhile, ITGA7 knockdown decreased apoptotic cell death in thyroid cells but promoted the expressions of N-cadherin and vimentin and decreased E-cadherin expression by epithelial-to-mesenchymal transition, which may induce invasion and migration. In conclusion, these results indicated that ITGA7 is involved in the progress of PTC and might act as a tumor suppressor gene.

Scavenger receptor class A, member 5 is associated with thyroid cancer cell lines progression via epithelial-mesenchymal transition

Thyroid cancer (TC) has become one of most common endocrine malignancies in recent decades. Due to gene background polymorphism, it's outcome goes quite differently in each patient. For exploring the mechanism, we performed whole transcriptome sequencing of paired papillary thyroid carcinoma (PTC) and adjacent thyroid tissues. As a result, scavenger receptor class A member 5 (SCARA5) might be a crucial anti-oncogene associated with PTC. By RT-qPCR, we first detected the expression of SCARA5 in PTC tissue and three type of TC cell lines. Besides, The Cancer Genome Atlas (TCGA) data were gathered to analysis the relationship between SCARA5 and clinical feature. A series of loss-function experiments in TC cell lines (KTC-1 and BCPAP) to investigate the function of SCARA5 in PTC. The results showed that SCARA5 expression in PTC was lower than adjacent normal tissue. And, it's consistent with the TCGA database. After analyse the correlation between SCARA5 expression and clinicopathological features in TCGA database, we discovered that downregulated SCARA5 is significantly connected age (P = .04) and tumour size (P = .032). Knockdown of SCARA5 in TC cell line could significantly increase the function of cells proliferation, colony formation, migration, and invasion. Furthermore, we also proved that SCARA5 could modulate the expression of epithelial-mesenchymal transition-related proteins, which influence invasion and migration. To best of our knowledge, SCARA5 is a suppressor gene which was associated with PTC and might be a potential therapeutic target in the future. SIGNIFICANCE OF THE STUDY: Thyroid cancer (TC) has become one of most common endocrine malignancies in recent decades. By whole transcriptome sequencing of paired papillary thyroid carcinoma (PTC) and adjacent thyroid tissues, author discovered that scavenger receptor class A member 5 (SCARA5) might be crucial anti-oncogene associated with PTC. Furthermore, knocking-down of SCARA5 in TC cell line can increase the function of cells proliferation, colony formation, migration, and invasion. Author also proved that SCARA5 could modulate the expression of epithelial-mesenchymal transition-related proteins.

Lenvatinib and sorafenib for differentiated thyroid cancer after radioactive iodine: a systematic review and economic evaluation

BACKGROUND

Thyroid cancer is a rare cancer, accounting for only 1% of all malignancies in England and Wales. Differentiated thyroid cancer (DTC) accounts for ≈94% of all thyroid cancers. Patients with DTC often require treatment with radioactive iodine. Treatment for DTC that is refractory to radioactive iodine [radioactive iodine-refractory DTC (RR-DTC)] is often limited to best supportive care (BSC).

OBJECTIVES

We aimed to assess the clinical effectiveness and cost-effectiveness of lenvatinib (Lenvima®; Eisai Ltd, Hertfordshire, UK) and sorafenib (Nexar®; Bayer HealthCare, Leverkusen, Germany) for the treatment of patients with RR-DTC.

DATA SOURCES

EMBASE, MEDLINE, PubMed, The Cochrane Library and EconLit were searched (date range 1999 to 10 January 2017; searched on 10 January 2017). The bibliographies of retrieved citations were also examined.

REVIEW METHODS

We searched for randomised controlled trials (RCTs), systematic reviews, prospective observational studies and economic evaluations of lenvatinib or sorafenib. In the absence of relevant economic evaluations, we constructed a de novo economic model to compare the cost-effectiveness of lenvatinib and sorafenib with that of BSC.

RESULTS

Two RCTs were identified: SELECT (Study of [E7080] LEnvatinib in 131I-refractory differentiated Cancer of the Thyroid) and DECISION (StuDy of sorafEnib in loCally advanced or metastatIc patientS with radioactive Iodine-refractory thyrOid caNcer). Lenvatinib and sorafenib were both reported to improve median progression-free survival (PFS) compared with placebo: 18.3 months (lenvatinib) vs. 3.6 months (placebo) and 10.8 months (sorafenib) vs. 5.8 months (placebo). Patient crossover was high (≥ 75%) in both trials, confounding estimates of overall survival (OS). Using OS data adjusted for crossover, trial authors reported a statistically significant improvement in OS for patients treated with lenvatinib compared with those given placebo (SELECT) but not for patients treated with sorafenib compared with those given placebo (DECISION). Both lenvatinib and sorafenib increased the incidence of adverse events (AEs), and dose reductions were required (for > 60% of patients). The results from nine prospective observational studies and 13 systematic reviews of lenvatinib or sorafenib were broadly comparable to those from the RCTs. Health-related quality-of-life (HRQoL) data were collected only in DECISION. We considered the feasibility of comparing lenvatinib with sorafenib via an indirect comparison but concluded that this would not be appropriate because of differences in trial and participant characteristics, risk profiles of the participants in the placebo arms and because the proportional hazard assumption was violated for five of the six survival outcomes available from the trials. In the base-case economic analysis, using list prices only, the cost-effectiveness comparison of lenvatinib versus BSC yields an incremental cost-effectiveness ratio (ICER) per quality-adjusted life-year (QALY) gained of £65,872, and the comparison of sorafenib versus BSC yields an ICER of £85,644 per QALY gained. The deterministic sensitivity analyses show that none of the variations lowered the base-case ICERs to < £50,000 per QALY gained.

LIMITATIONS

We consider that it is not possible to compare the clinical effectiveness or cost-effectiveness of lenvatinib and sorafenib.

CONCLUSIONS

Compared with placebo/BSC, treatment with lenvatinib or sorafenib results in an improvement in PFS, objective tumour response rate and possibly OS, but dose modifications were required to treat AEs. Both treatments exhibit estimated ICERs of > £50,000 per QALY gained. Further research should include examination of the effects of lenvatinib, sorafenib and BSC (including HRQoL) for both symptomatic and asymptomatic patients, and the positioning of treatments in the treatment pathway.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017055516.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Multikinase Inhibitor Treatment in Thyroid Cancer

Thyroid cancer is the most common endocrine malignancy. Most thyroid cancer types respond well to conventional treatment consisting of surgery and radioactive iodine (RAI) therapy. Unfortunately, some thyroid cancer types are resistant to surgical and RAI therapy. Multikinase inhibitors (MKIs) can be used in the treatment of advanced refractory thyroid cancers. The objective of this review is to give an update on MKI treatment (lenvatinib, sorafenib, sunitinib, cabozantinib, pazopanib, vandetanib) of thyroid cancer, regarding its efficacy and safety profile. We evaluated 212 articles through a PubMed search. A total of 20 articles met the inclusion and none the exclusion criteria. The studies showed promising progression-free survival rates compared to placebo treatment from earlier studies and similar or better results compared to the SELECT and DECISION trials. Adverse effects (AEs) are substantial in the treatment with MKIs. Almost all patients treated with these novel drugs experienced AEs. It is therefore crucial to focus on the management of AEs for a decent long-term outcome. The AEs are often more severe in patients with high efficacy of MKIs, which could indicate a correlation. Taken together, the novel therapeutic regimen with MKIs has shown favorable results in otherwise treatment-resistant thyroid cancer.

Treatment-related adverse effects with TKIs in patients with advanced or radioiodine refractory differentiated thyroid carcinoma: a systematic review and meta-analysis

Background

Tyrosine kinase inhibitors (TKIs) have been administered to advanced or radio-iodine refractory differentiated thyroid carcinoma (RR-DTC) patients for years. We performed a pooled analysis to explore the frequency of severe adverse effects in advanced or RR-DTC patients treated with sorafenib and lenvatinib.

Methods

We performed a comprehensive search of computerized databases, including PubMed, Web of Science, Ovid, EMASE, and the Cochrane Library, from the drugs' inception to July 2018 to identify clinical trials. All grade and severe adverse events (AEs; grade ≥3) were analyzed. This meta-analysis was conducted in accordance with PRISMA guidelines.

Results

In total, seve studies published from 2012-2018 with 657 patients were eligible for this study. We included two studies (238 patients) that received 200 mg sorafenib twice and five studies (419 patients) that received 24 mg lenvatinib daily. The frequency of AEs was different among the two drugs. Patients in the sorafenib group had a significantly higher frequency of all grade hand-foot syndrome, hypocalcemia, rash, elevated alanine aminotransferase (ALT), and elevated aspartate aminotransferase (AST). Conversely, the lenvatinib group experienced more frequent all grade voice change, hypertension, nausea, and vomiting compared with those with sorafenib. For grade ≥3 adverse effects, hand-foot syndrome, hypocalcemia, and elevated ALT were more frequent in sorafenib-treated patients. Moreover, lenvatinib-treated patients had a significantly higher incidence of severe weight loss, hypertension, and nausea.

Conclusion

Significant differences in common adverse effects, such as all-grade and severe AEs, were detected between sorafenib and lenvatinib in the current study. Early intervention and management of treatment-related AEs (TRAEs) can minimize the impact on patients' quality-of-life, and avoid unnecessary dose reductions and treatment-related discontinuations.

CYP24A1 depletion facilitates the antitumor effect of vitamin D3 on thyroid cancer cells

It has been demonstrated that 25-hydroxyvitamin-D3-24-hydroxylase (CYP24A1) is a key enzyme that neutralizes vitamin D activity, which may have an anti-tumor effect. Therefore, the aim of the current study was to explore the effect of the active metabolite of vitamin D, 1,25-dihydroxyvitamin D (1,25-D3) on thyroid cancer cells following the downregulation of CYP24A1. A Cell Counting Kit-8 assay identified that CYP24A1 knockdown enhanced the anti-proliferative effects of 1,25-D3 on thyroid cancer cells. Furthermore, the results of the scratch wound and Transwell assays indicated that CYP24A1 knockdown enhanced the inhibitory effect of 1,25-D3 on cell migration. The results from reverse transcription-quantitative polymerase chain reaction and western blot analysis indicated that treatment with 1,25-D3 and CYP24A1 knockdown synergistically enhanced the expression of the epithelial-related gene E-cadherin and decreased the expression of the mesenchymal-related genes N-cadherin and vimentin. Following CYP24A1 knockdown and treatment with 1,25-D3, the expression of matrix metalloproteinase 2 and metalloproteinase inhibitor 1 were significantly decreased and increased, respectively, compared with the group that underwent treatment with 25-D3 alone. Furthermore, protein kinase B (Akt) and β-catenin activity was significantly decreased by this synergetic effect compared with the group that underwent treatment with 1,25-D3 alone. The results of the current study suggest that CYP24A1 knockdown contributes to the anti-tumor effect of 1,25-D3 and that this effect may be due to deactivation of the Akt and β-catenin signaling pathways. Therefore, CYP24A1 knockdown and 1,25-D3 treatment may be used synergistically as a novel therapeutic strategy to treat patients with thyroid cancer.

Long Noncoding RNA LINC003121 Inhibits Proliferation and Invasion of Thyroid Cancer Cells by Suppression of the Phosphatidylinositol-3-Kinase (PI3K)/Akt Signaling Pathway

BACKGROUND The aim of this study was to explore the potential effects of long noncoding RNA (lncRNA) LINC003121 on thyroid cancer (TC) cell proliferation and invasion and to explore their possible mechanisms with the involvement of the PI3K/Akt signaling pathway. MATERIAL AND METHODS We enrolled 211 thyroid cancer tissues and 70 adjacent normal tissues in this study. TC cell lines K1, SW579, and 8505C and the human thyroid follicular cell line Nthy-ori3-1 were selected and assigned into blank, control vectors, LINC00312 vectors, si-control, and si-LINC00312 groups. Quantitative real-time PCR was used to determine the levels of LINC003121 and Western blotting was used to detect the protein expression of MMP-9, PI3K, t-Akt, and p-Akt. Cell proliferation was assessed by CCK8 assay and EdU incorporation assay, and cell invasion was assessed by Transwell assay. RESULTS The expression of LINC00312 was significantly decreased in TC tissues and cell lines. In an in vitro experiment, si-LINC00312 significantly promoted the invasion and proliferation of TC cells. Conversely, overexpression of LINC00312 decreased cell proliferation and invasion in vitro, and decreased tumorigenicity in TC xenograft models in nude mice. LINC00312-mediated tumor suppression in TC cells may occur via suppression of activation of the PI3K/Akt signaling pathway and expression of MMP-9, and the role of MMP-9 expression induced by overexpressed LINC00312 or si-LINC00312 could be weakened by LY294002 (PI3K inhibitor). CONCLUSIONS LINC00312 can act as a tumor-suppressor in TC by attenuating the PI3K/Akt signaling pathway, and LINC00312 could be a novel diagnosis biomarker and a promising therapeutic target for TC patients.

Tyrosine kinase inhibitors for advanced or metastatic thyroid cancer: a meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Radioiodine-refractory advanced or metastatic thyroid cancer has poor prognosis. We conducted a meta-analysis of randomized controlled trials to evaluate the effectiveness and safety of tyrosine kinase inhibitors (TKIs) for advanced or metastatic thyroid cancer treatment.

METHODS

Studies published up to April 2017 were selected. The pooled effect size was calculated through meta-analysis by using random effects models. Outcomes were overall survival (OS), progression-free survival (PFS), objective response rate (RR), and adverse events (AEs).

RESULTS

Six studies examining 1615 patients were included. TKI treatment significantly improved PFS in patients with differentiated thyroid cancer (DTC; hazard ratio [HR] = 0.43; 95% confidence interval [CI], 0.23-0.82) and those with medullary thyroid cancer (MTC; HR = 0.36; 95% CI, 0.22-0.58). TKI treatment significantly prolonged OS in patients with DTC (HR = 0.74; 95% CI, 0.58-0.95). The TKI treatment group exhibited a significantly improved partial response rate (risk ratio = 15.8; 95% CI, 1.77-140.69) but a significantly higher number of AEs compared with the control group.

CONCLUSION

TKIs significantly improved PFS and RR in patients with advanced or metastatic DTC or MTC. We recommend thoroughly evaluating patients' health status and cautiously using TKIs to maximize their benefits and minimize their toxicity.

Case report: Whole exome sequencing of circulating cell-free tumor DNA in a follicular thyroid carcinoma patient with lung and bone metastases

Metastatic follicular thyroid carcinoma (FTC), unresectable or resistance to radioactive iodine, is associated with poor survival. It is believed that this kind of FTC is driven by mutated genes. However, what kind of changes of genome and underlying mechanisms are elusive. The aim of this article is to understand whether there are somatic mutations in circulating cell-free tumor DNA (cfDNA) in a FTC patient with lung and bone metastases. A 55-year-old woman was diagnosed with FTC with bone and lung metastases. Appropriate amounts of DNA were extracted from formalin-fixed, paraffin-embedded thyroid tumor, peripheral cell-free plasma, and peripheral blood leukocytes and then sequenced. The significance of DNA sequencing was evaluated. There were 13,519 common variants in both tissue DNA and cfDNA. Fifty-five somatic mutations were identified in tumor, with 5 of them nonsynonymous. Seventy-two somatic mutations were found in cfDNA, with 2 of them causing amino acid change. Sixteen common alterations existed in both samples, that is, 31.3% of all the tissue somatic mutations. This pilot study provided proof that cfDNA represents the genomic characteristics of FTC primary tissue DNA well, but also metastatic tumors. Further studies are needed to better prove the effectiveness of cfDNA in the field of thyroid cancer metastatic mechanism research and real-time monitoring.

Dual effects for lovastatin in anaplastic thyroid cancer: the pivotal effect of transketolase (TKT) on lovastatin and tumor proliferation

This study tested the hypothesis that the effects of lovastatin on anaplastic thyroid cancer cell growth are mediated by upregulation of transketolase (TKT) expression. The effects of lovastatin on TKT protein levels in ARO cells were determined using western blot and proteomic analyses. After treatment with lovastatin and oxythiamine, the in vitro and in vivo growth of ARO cells was determined using 3-(4,5-Dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assays and tumor xenografts in nude mice. TKT protein expression in the ARO tumors was assessed using immunohistochemistry analysis. Proteomic analysis revealed that 25 µM lovastatin upregulated TKT expression. Co-treatment of ARO cells with 1 µM lovastatin + 1 µM oxythiamine increased TKT protein expression compared with control levels; however, no differences were observed with 10 µM lovastatin + 1 µM oxythiamine. Furthermore, treatment with either oxythiamine or lovastatin alone reduced ARO tumor expression of TKT, as well as decreased ARO cell proliferation in vitro and tumor growth in vivo. However, mice treated with both lovastatin and oxythiamine at the same time had tumor volumes similar to that of the untreated control group. We conclude that either lovastatin or oxythiamine reduced ARO cell growth; however, the combination of these drugs resulted in antagonism of ARO tumor growth.

All-trans retinoic acid suppresses malignant characteristics of CD133-positive thyroid cancer stem cells and induces apoptosis

Recently, diagnoses of radioiodine-refractory differentiated thyroid cancer (RAI-R DTC) have become more common; prognosis is poor. It has been suggested that cancer stem cells account for radiotherapy resistance. By flow cytometry, different expression percents of CD133 and OCT4 in thyroid cancer cell lines were detected. By real-time quantitative PCR, different mRNA expression of CD133, OCT4, GLUT1, thyroglobulin (TG), thyroperoxidase (TPO) and sodium iodine symporter (NIS) was analyzed; the localization of CD133, OCT4, and NIS expression was examined using immunofluorescence confocal microscopy. Different expression of CD133, OCT4, and NIS in 21 human thyroid cancer and nodule tissues was investigated using immunohistochemistry. CD133-positive cells were isolated by magnetic sorting. Stronger colony formation ability of CD133-positive and weaker ability of CD133-negative cells in vivo were examined by colony formation. The effects of all-trans retinoic acid (ATRA) on CD133-positive cells in vivo were explored with Cell Counting Kit-8, colony formation, apoptosis, cell cycle, and ethynyl deoxyuridine assays. The ARO cell line and RAI-R DTC tissue specimens had more CD133-positive cells. NIS expression was significantly lower in RAI-R DTC tissue compared to radioiodine-sensitive DTC (RAI-DTC) tissue and specimens from patients with thyroid nodule. ATRA inhibited the stem cell characteristics of CD133-positive cells and induced CD133-positive cell differentiation to CD133-negative cells, and promoted CD133-positive cell apoptosis.

Signaling Pathways in Thyroid Cancer

The morbidity of thyroid cancer is increasing gradually year by year, showing an increasing tendency in nationality, sex, age, tumor size, and tumor staging. The changes of thyroid cell genes, signaling pathways, and related molecular dysfunction promote the occurrence, development, invasion, and metastasis of thyroid cancer. Surgical operation, radioiodine, and endocrinotherapy models can achieve a better prognosis for most patients with thyroid cancer. Although targeted therapeutic drugs bring possible therapeutic opportunities for refractory thyroid cancer, there is a great gap between their predictive value and their actual efficacy. Currently, there is still no completely effective drug for the treatment. Based on the signaling pathways, the "reclaim therapy" for residual tumor and systemic intervention aims to increase anticancer ability and to encourage new directions and thoughts in the treatment of refractory thyroid cancer.

The role of hepatic trans-arterial chemoembolization in metastatic medullary thyroid carcinoma: a specialist center experience and review of the literature

BACKGROUND

Liver metastases are relatively common in patients with metastatic medullary thyroid carcinoma (MTC), carrying a negative impact on disease prognosis. The options for selective therapy of liver metastases in MTC patients are limited to catheter-guided procedures such as trans-arterial chemoembolization (TACE). Data regarding the effectiveness and safety of this procedure in MTC are limited.

AIM

To explore the clinical outcome, survival and safety profile of TACE for liver metastases in a group of MTC patients.

METHODS

Retrospective case series of patients treated at a single tertiary University Medical Center from 2005 to 2015.

RESULTS

Seven consecutive patients (mean age 64.5 ± 10.9 years, 5 females) with histologically confirmed MTC with liver metastases were included. Metastatic involvement of the liver was less than 50% of the liver volume in all patients. The median size of the largest liver lesion was 40 ± 6.9 mm. The patients underwent in total 20 sessions of TACE. Clinical improvement as well as tumor response (PR) were observed in all patients. The median time to tumor progression was 38 months (range 8-126). Three patients were still alive at the end of the follow-up period (a median overall survival rate of 57 ± 44 months).

CONCLUSION

TACE in MTC patients with hepatic metastases is usually well tolerated and induces both clinical improvement and tumor response for prolonged periods of time in the majority of patients. This therapeutic option should always be considered, irrespective of the presence of extrahepatic metastasis.

The BH3 mimetic drug ABT-737 induces apoptosis and acts synergistically with chemotherapeutic drugs in thyroid carcinoma cells

BACKGROUND

Patients with dedifferentiated and anaplastic thyroid carcinomas that do not take up radioiodine are resistant to chemotherapeutic treatment and external irradiation and thus are difficult to treat. Direct induction of apoptosis is a promising approach in these apoptosis-resistant tumor cells. The BH3 mimetic ABT-737 belongs to a new class of drugs that target anti-apoptotic proteins of the BCL-2 family and facilitate cell death. The purpose of this study was to investigate the effect of ABT-737 alone or in combination with chemotherapeutic drugs on thyroid carcinoma cell lines.

METHODS

A total of 16 cell lines derived from follicular, papillary, and anaplastic thyroid carcinomas were treated with ABT-737. Cell viability was measured with MTT assay. Cell death was determined by cell cycle phase distribution and subG1 peak analyses, determination of caspase 3/7 activity and caspase cleavage products, lactate dehydrogenase (LDH) liberation assays and LC3 analysis by western blot.

RESULTS

The number of viable cells was decreased in all cell lines examined after ABT-737 treatment, with IC50 values ranging from 0.73 to 15.6 μM. Biochemical markers of apoptosis like caspase activities, caspase cleavage products and DNA fragmentation determined as SubG1 peak were elevated after ABT-737 treatment, but no LC3 cleavage was induced by ABT-737 indicating no autophagic processes. In combination with doxorubicin and gemcitabine, ABT-737 showed synergistic effects on cell viability.

CONCLUSIONS

With these experiments we demonstrated the efficacy of the BH3 mimetic drug ABT-737 against dedifferentiated thyroid carcinoma cells of various histological origins and showed synergistic effects with chemotherapeutic drugs. ABT-737-treated cells underwent an apoptotic cell death. ABT-737 and related BH3 mimetic drugs, alone or in combination, may thus be of value as a new therapeutic option for dedifferentiated thyroid carcinomas.

Diagnostic Efficacy of Ultrasonographic Characteristics of Thyroid Carcinoma in Predicting Cervical Lymph Node Metastasis

The goals of this study were to determine the ultrasonographic characteristics of thyroid carcinoma (TC) and to explore the diagnostic efficacy of these ultrasonographic characteristics in predicting cervical lymph node metastasis (LNM). From June 2012 to June 2014, a total of 186 TC patients were recruited from the Central Hospital of Chengde City, Hebei, China. We divided them into two groups: the metastatic group comprised 129 nodules (n = 86), and the non-metastatic group 117 nodules (n = 100). Univariate and multivariate analyses were used to evaluate the relationship between ultrasonographic characteristics and cervical LNM. Spectral Doppler ultrasound was employed to estimate peak systolic velocity, pulsatility index and resistive index. Receiver operating characteristic curves were drawn to evaluate the efficacy of ultrasonographic characteristics in predicting cervical LNM. The sensitivity, specificity, positive predictive value and negative predictive value of ultrasonographic diagnosis were 81.40% (105/129), 92.32% (108/117), 92.11% (105/114) and 81.82% (108/132), respectively. Cervical LNM in TC frequently occurred at the cervical level VI (37.98%) and was located mainly in the middle pole (46.51%) or lower pole (41.09%). Peak systolic velocity and resistive index values were significantly higher in the metastatic group than in the non-metastatic group (both p < 0.001). Multivariate analysis revealed that nodular diameter, capsular invasion, microcalcification and flow grade were risk factors for TC patients with cervical LNMs (all p < 0.05). Furthermore, receiver operating characteristic curve analysis revealed that nodular diameter, capsular invasion, microcalcification and flow grade had excellent accuracy in predicting cervical LNM. We conclude that ultrasonographic characteristics of TC, including maximum nodular diameter, capsular invasion, microcalcification and flow grade, may predict cervical LNM.

Induction of atypical cell death in thyroid carcinoma cells by the indirubin derivative 7-bromoindirubin-3'-oxime (7BIO)

BACKGROUND

The indirubin derivative 7-bromoindirubin-3'-oxime (7BIO) has already shown anticancer properties by causing cell death in some tumour cell lines and may be a new therapeutic option for treatment-resistant tumour cells. Since dedifferentiated and anaplastic thyroid carcinomas do not take up radioiodine and are insensitive to chemotherapeutic treatment and external radiation, direct cell death induction in these tumour cells may be a promising approach. We thus investigated the effect of 7BIO on thyroid carcinoma cell lines of different histological origins and characterized the type of cell death induction by 7BIO.

METHODS

Cell viability was measured with MTT assay. Cell death was analysed by caspase 3/7 activity, lactate dehydrogenase liberation, caspase cleavage products, DNA fragmentation, cell cycle phase distribution and LC3B analysis.

RESULTS

After 7BIO treatment, cell viability was reduced in all 14 thyroid carcinoma cell lines investigated. Treated cells showed DNA fragmentation, cell cycle arrest and lactate dehydrogenase liberation but no LC3B cleavage. Caspase activation following 7BIO treatment was found in five of six cell lines investigated. Interestingly, inhibition of caspases had no effect on viability of the cells after 7BIO incubation.

CONCLUSIONS

Our results indicate that 7BIO efficiently killed dedifferentiated thyroid carcinoma cells. It induced a non-classical kind of cell death that was caspase-independent and includes DNA fragmentation. 7BIO and related indirubin components thus may have value as a new therapeutic option for dedifferentiated thyroid cancer irrespective of the exact target molecules and the kind of cell death they induce.

Overdiagnosis of thyroid cancer: answers to five key questions

Thyroid cancer fulfills the criteria for overdiagnosis by having a reservoir of indolent cancers and practice patterns leading to the diagnosis of incidental cancers from the reservoir. The occurrence of overdiagnosis is also supported by population-based data showing an alarming rise in thyroid cancer incidence without change in mortality. Because one of the activities leading to overdiagnosis is the workup of incidental thyroid nodules detected on imaging, it is critical that radiologists understand the issue of overdiagnosis and their role in the problem and solution. This article addresses 1) essential thyroid cancer facts, 2) the evidence supporting overdiagnosis, 3) the role of radiology in overdiagnosis, 4) harms of overdiagnosis, and 5) steps radiologists can take to minimize the problem.

Cell death induction by the BH3 mimetic GX15-070 in thyroid carcinoma cells

Background

The evasion of cell death is one of the hallmarks of cancer, contributing to both tumor progression and resistance to therapy. Dedifferentiated and anaplastic thyroid carcinomas that do not take up radioiodine are resistant to conventional anticancer treatments and patients with these tumors are difficult to treat. BH3 mimetics are a new class of drugs that target anti-apoptotic proteins of the BCL-2 family and promote cell death. The purpose of this study was to analyze the molecular effects of the BH3 mimetic GX15-070 on thyroid carcinoma cell lines and to characterize cell death induced by GX15-070.

Methods

A total of 17 cell lines derived from follicular, papillary, and anaplastic thyroid carcinomas were treated with GX15-070. Cell viability was measured with MTT assay while cell cycle phase distribution and subG1 peaks were determined after propidium iodide staining. We assessed cell death via the caspase 3/7 activity, caspase cleavage products, lactate dehydrogenase (LDH) liberation assays, and a LC3 analysis by western blot. Ultrastructural changes were analysed by electron microscopy of GX15-070-treated cells.

Results

After GX15-070 treatment, the number of viable cells was decreased in all cell lines examined, with IC50 values ranging from 48nM to 3.25 μM. We observed biochemical markers of autophagic cell death and necrosis like LC3 conversion and LDH release after the GX15-070 treatment. Electron microscopy revealed several common characteristic ultrastructural changes like swelling of mitochondria, dilatation of rough endoplasmic reticulum, membrane blebbing and formation of vacuoles. GX15-070 treatment induced DNA fragmentation detected by subG1-peak induction and an arrest in G1 phase of the cell cycle. Caspase activation after GX15-070 incubation was detected but had no effect on viability of cells.

Conclusions

With these experiments we demonstrated the efficacy of the BH3 mimetic drug GX15-070 acting against dedifferentiated thyroid carcinoma cells of various histological origins by the induction of cell death. GX15-070-treated cells underwent non-classical cell death with signs of apoptosis, autophagy and necrosis in parallel. GX15-07 and related compounds thus may be a new therapeutic option for dedifferentiated thyroid carcinoma of various histological subtypes.

Selective use of vandetanib in the treatment of thyroid cancer

Vandetanib is a once-daily orally available tyrosine kinase inhibitor that works by blocking RET (REarranged during Transfection), vascular endothelial growth factor receptor (VEGFR-2, VEGFR-3), and epidermal growth factor receptor and to a lesser extent VEGFR-1, which are important targets in thyroid cancer (TC). It is emerging as a potentially effective option in the treatment of advanced medullary thyroid cancer (MTC) and in dedifferentiated papillary thyroid cancer not responsive to radioiodine. The most important effect of vandetanib in aggressive MTC is a prolongation of progression-free survival and a stabilization of the disease. Significant side effects have been observed with the vandetanib therapy (as fatigue, hypertension, QTc prolongation, cutaneous rash, hand-and-foot syndrome, diarrhea, etc), and severe side effects can require the suspension of the drug. Several studies are currently under way to evaluate the long-term efficacy and tolerability of vandetanib in MTC and in dedifferentiated papillary TC. The efficacy of vandetanib in patients with MTC in long-term treatments could be overcome by the resistance to the drug. However, the effectiveness of the treatment could be ameliorated by the molecular characterization of the tumor and by the possibility to test the sensitivity of primary TC cells from each subject to different tyrosine kinase inhibitor. Association studies are evaluating the effect of the association of vandetanib with other antineoplastic agents (such as irinotecan, bortezomib, etc). Further research is needed to determine the ideal therapy to obtain the best response in terms of survival and quality of life.

Therapy of endocrine disease: response and toxicity of small-molecule tyrosine kinase inhibitors in patients with thyroid carcinoma: a systematic review and meta-analysis

CONTEXT

Many tyrosine kinase inhibitors (TKIs) have been studied in patients with thyroid carcinoma (TC). However, the effect and toxicity of various TKIs in differentiated TC (DTC) and medullary TC (MTC) patients have not been directly compared. The aim of the present systematic review and meta-analysis was to systematically summarize response and toxicity of TKIs in TC patients.

METHODS

All major databases were systematically searched for publications on TKIs in TC. Primary endpoint was objective response; secondary endpoints were clinical benefit, percentage TKI dose reduction/discontinuation, hand-foot syndrome, diarrhea, and nausea/vomiting. Meta-analysis was performed using an exact likelihood approach and a logistic regression. Pooled percentages and 95% CIs were reported.

RESULTS

In total, 22 publications were included. For DTC patients, gefitinib induced no objective responses. Pooled percentage was highest for pazopanib, 49 (95% CI 33-64)%, and was 17 (95% CI 12-24)% for sorafenib. For MTC, gefitinib and imatinib induced no objective responses, whereas sunitinib induced objective response in 43 (95% CI 14-77)%. For vandetanib and cabozantinib, these numbers were 40 (95% CI 34-46)% and 27 (95% CI 22-32)% respectively. Clinical benefit was found in 53 (95% CI 48-59)% of DTC patients on sorafenib, and in 84 (95% CI 79-88)% and 55 (95% CI 49-61)% of MTC patients on vandetanib and cabozantinib respectively. All TKIs were associated with considerable toxicity.

CONCLUSION

The currently studied TKIs show a modest response, while side effects are not negligible. Therefore, we suggest to solely consider TKIs in TC patients with rapid progressive disease, for whom the benefits of treatment outweigh toxicity.

Sorafenib inhibits intracellular signaling pathways and induces cell cycle arrest and cell death in thyroid carcinoma cells irrespective of histological origin or BRAF mutational status

BACKGROUND

Patients with dedifferentiated or anaplastic thyroid carcinomas currently lack appropriate treatment options. Kinase inhibitors are among the most promising new agents as alternative strategies. The BRAF- and multi-kinase inhibitor, sorafenib, has already shown antitumor effects in thyroid carcinoma patients in a phase III clinical trial. In this study we aim to better characterize molecular effects and efficacy of sorafenib against thyroid carcinoma cells with various histological origins and different BRAF mutational status. Analysis of different signaling pathways affected by sorafenib may contribute to assist a more specific therapy choice with fewer side effects. Twelve thyroid carcinoma cell lines derived from anaplastic, follicular and papillary thyroid carcinomas with wildtype or mutationally activated BRAF were treated with sorafenib. Growth inhibition, cell cycle arrest, cell death induction and inhibition of intracellular signaling pathways were then comprehensively analyzed.

METHODS

Cell viability was analyzed by MTT assay, and the cell cycle was assessed by flow cytometry after propidium iodide staining. Cell death was assessed by lactate dehydrogenase liberation assays, caspase activity assays and subG1 peak determinations. Inhibition of intracellular pathways was analyzed in dot blot and western blot analyses.

RESULTS

Sorafenib inhibited proliferation of all thyroid carcinoma cell lines tested with IC50 values ranging between 1.85 and 4.2 μM. Cells derived from papillary carcinoma harboring the mutant BRAF (V600E) allele were slightly more sensitive to sorafenib than those harboring wildtype BRAF. Cell cycle analyses and caspase assays showed a sorafenib-dependent induction of apoptosis in all cell lines, whereas increased lactate dehydrogenase release suggested cell membrane disruption. Sorafenib treatment caused a rapid inhibition of various MAP kinases in addition to inhibiting AKT and receptor tyrosine kinases.

CONCLUSIONS

Sorafenib inhibited multiple intracellular signaling pathways in thyroid carcinoma cells, which resulted in cell cycle arrest and the initiation of apoptosis. Sorafenib was effective against all thyroid carcinoma cell lines regardless of their tumor subtype origin or BRAF status, confirming that sorafenib is therapeutically beneficial for patients with any subtype of dedifferentiated thyroid cancer. Inhibition of single intracellular targets of sorafenib in thyroid carcinoma cells may allow the development of more specific therapeutic intervention with less side effects.

Novel approaches in anaplastic thyroid cancer therapy

Anaplastic thyroid cancer (ATC), accounting for less than 2% of all thyroid cancer, is responsible for the majority of death from all thyroid malignancies and has a median survival of 6 months. The resistance of ATC to conventional thyroid cancer therapies, including radioiodine and thyroid-stimulating hormone suppression, contributes to the very poor prognosis of this malignancy. This review will cover several cellular signaling pathways and mechanisms, including RET/PTC, RAS, BRAF, Notch, p53, and histone deacetylase, which are identified to play roles in the transformation and dedifferentiation process, and therapies that target these pathways. Lastly, novel approaches and agents involving the Notch1 pathway, nuclear factor κB, Trk-fused gene, cancer stem-like cells, mitochondrial mutation, and tumor immune microenvironment are discussed. With a better understanding of the biological process and treatment modality, the hope is to improve ATC outcome in the future.

Accelerated disease progression after discontinuation of sorafenib in a patient with metastatic papillary thyroid cancer

Distant metastases from papillary thyroid carcinoma (PTC) are rare and are associated with a poor prognosis. Here, we describe a patient with metastatic PTC who was treated with a tyrosine kinase inhibitor (TKI, sorafenib) for several months that was acutely exacerbated by discontinuation. A 43-year-old male was diagnosed with PTC in February 2004 and underwent total thyroidectomy followed by two courses of high-dose radioactive iodine (RAI) therapy. Despite two additional courses of high-dose RAI therapy, lung and muscle metastases were developed. Treatment with sorafenib was begun in September 2010. After 11 months treatment of sorafenib, newly developed metastatic lesions were found in mediastinal lymph nodes, liver, and bones. Considered as treatment failure, the administration of sorafenib was discontinued. Two weeks after sorafenib treatment was stopped, the disease progressed abruptly and caused death of the patient by respiratory failure. In our patient, PTC progressed rapidly after the cessation of sorafenib treatment. Patients with several other types of cancer have also experienced such rapid disease progression, termed "flare-ups." Physicians should be aware that flare-ups may occur in advanced PTC patients following the cessation of TKI therapy.

Medical therapy for advanced forms of thyroid cancer

More options than ever before are currently available for medical therapy in patients who present with advanced thyroid cancer or develop surgically unresectable recurrences or symptomatic or progressive disease. The newer medical therapies have addressed the need to find effective therapies beyond the conventional treatment with radioactive iodine, thyroid stimulating hormone suppression, and palliative cytotoxic chemotherapy for patients with advanced thyroid cancer. Although tumor responses to these medical therapies vary by type of thyroid cancer and type of therapy selected, they remain encouraging and provide therapeutic options for selected patients while new drugs are in development.

Sorafenib in radioactive iodine-refractory, locally advanced or metastatic differentiated thyroid cancer: a randomised, double-blind, phase 3 trial

BACKGROUND

Patients with radioactive iodine ((131)I)-refractory locally advanced or metastatic differentiated thyroid cancer have a poor prognosis because of the absence of effective treatment options. In this study, we assessed the efficacy and safety of orally administered sorafenib in the treatment of patients with this type of cancer.

METHODS

In this multicentre, randomised, double-blind, placebo-controlled, phase 3 trial (DECISION), we investigated sorafenib (400 mg orally twice daily) in patients with radioactive iodine-refractory locally advanced or metastatic differentiated thyroid cancer that had progressed within the past 14 months. Adult patients (≥18 years of age) with this type of cancer were enrolled from 77 centres in 18 countries. To be eligible for inclusion, participants had to have at least one measurable lesion by CT or MRI according to Response Evaluation Criteria In Solid Tumors (RECIST); Eastern Cooperative Oncology Group performance status 0-2; adequate bone marrow, liver, and renal function; and serum thyroid-stimulating hormone concentration lower than 0·5 mIU/L. An interactive voice response system was used to randomly allocate participants in a 1:1 ratio to either sorafenib or matching placebo. Patients, investigators, and the study sponsor were masked to treatment assignment. The primary endpoint was progression-free survival, assessed every 8 weeks by central independent review. Analysis was by intention to treat. Patients in the placebo group could cross over to open-label sorafenib upon disease progression. Archival tumour tissue was examined for BRAF and RAS mutations, and serum thyroglobulin was measured at baseline and at each visit. This study is registered with ClinicalTrials.gov, number NCT00984282, and with the EU Clinical Trials Register, number EudraCT 2009-012007-25.

FINDINGS

Patients were randomly allocated on a 1:1 basis to sorafenib or placebo. The intention-to-treat population comprised 417 patients (207 in the sorafenib group and 210 in the placebo group) and the safety population was 416 patients (207 in the sorafenib group and 209 in the placebo group). Median progression-free survival was significantly longer in the sorafenib group (10·8 months) than in the placebo group (5·8 months; hazard ratio [HR] 0·59, 95% CI 0·45-0·76; p<0·0001). Progression-free survival improved in all prespecified clinical and genetic biomarker subgroups, irrespective of mutation status. Adverse events occurred in 204 of 207 (98·6%) patients receiving sorafenib during the double-blind period and in 183 of 209 (87·6%) patients receiving placebo. Most adverse events were grade 1 or 2. The most frequent treatment-emergent adverse events in the sorafenib group were hand-foot skin reaction (76·3%), diarrhoea (68·6%), alopecia (67·1%), and rash or desquamation (50·2%).

INTERPRETATION

Sorafenib significantly improved progression-free survival compared with placebo in patients with progressive radioactive iodine-refractory differentiated thyroid cancer. Adverse events were consistent with the known safety profile of sorafenib. These results suggest that sorafenib is a new treatment option for patients with progressive radioactive iodine-refractory differentiated thyroid cancer.

FUNDING

Bayer HealthCare Pharmaceuticals and Onyx Pharmaceuticals (an Amgen subsidiary).

Evaluation of PTEN, PI3K, MTOR, and KRAS expression and their clinical and prognostic relevance to differentiated thyroid carcinoma

Aim of the study

Important signalling pathways play fundamental roles in the pathogenesis of thyroid carcinoma (TC). PTEN, mTOR, PI3K-p85 and K-Ras are the principal factors involved in these signalling pathways. To immunohistochemically examine the expressions of PI3K, mTOR and PTEN in patients suffering from follicular TC, papillary TC or variants thereof, as well as to investigate KRAS mutations via PCR to determine their clinical and prognostic relevance to differentiated thyroid cancer.

Material and methods

The expression of PTEN, PI3K-p85 and mTOR was immunohistochemically examined, and the mutation of K-Ras was examined via PCR. The results obtained were compared to the clinico-pathologic characteristics of the patients.

Results

A significant correlation was found between p85 expression and lymphovascular invasions and between PTEN expression and multifocality (p = 0.048 and p = 0.04, respectively), and a correlation between p85 and capsular invasion was found, with a borderline statistical significance (p = 0.056). No expression of PTEN, p85 or Mtor was detected in normal tissue. K-Ras mutation was examined in 66 of the 101 patients (57.4%), and the percentage of patients exhibiting a K-Ras mutation was 17.4%. All of the patients exhibiting a K-Ras mutation were women (p = 0.047). The disease-free survival was 44.6 months (95% CI: 37.9–51.3) and was statistically significantly higher in the group that displayed level 1 or lower expression of p85 (p = 0.043).

Conclusions

The expression levels of the aforementioned markers were significantly higher in TC cells than in normal tissue. A significant correlation was detected between K-Ras mutation and gender. This study demonstrates that p85 and PTEN are markers that should be evaluated in further studies of TC.

Medical management of metastatic medullary thyroid cancer

Medullary thyroid cancer (MTC) is an aggressive form of thyroid cancer that occurs in both heritable and sporadic forms. Discovery that mutations in the rearranged during transfection (RET) proto-oncogene predispose to familial cases of this disease has allowed for presymptomatic identification of gene carriers and prophylactic surgery to improve the prognosis of these patients. A significant number of patients with the sporadic type of MTC and even those with familial disease still present with lymph node or distant metastases, making surgical cure difficult. Over the past several decades, many different types of therapy for metastatic disease have been attempted with limited success. Improved understanding of the molecular defects and pathways involved in both familial and sporadic MTC has resulted in new hope for these patients with the development of drugs targeting the specific alterations responsible. This new era of targeted therapy with kinase inhibitors represents a significant step forward from previous trials of chemotherapy, radiotherapy, and hormone therapy. Although much progress has been made, additional agents and strategies are needed to achieve durable, long-term responses in patients with metastatic MTC. This article reviews the history and results of medical management for metastatic MTC from the early 1970s up until the present day.

Nuclear receptor expression in human differentiated thyroid tumors

BACKGROUND

Nuclear receptors (NRs) play a key role in endocrine signaling and metabolism and are important therapeutic targets in a number of hormone-dependent malignancies. Studies on the role of NRs in thyroid cancer are limited.

OBJECTIVE

The objective of the study was to examine systematically the expression of the 48 human NRs in a series of benign and malignant thyroid tissues. Within the papillary carcinoma cohort, we sought to determine if NR expression differed significantly by BRAF mutation status.

PATIENTS AND METHODS

RNA was isolated from multinodular goiter (MNG; n=6), papillary carcinoma (PTC, n=14), follicular carcinoma (FC; n=5), and Hürthle cell carcinoma (HCC; n=7). The 48 human NRs were profiled in this panel by quantitative real time polymerase chain reaction. Protein expression for selected NRs (Rev-erbα and LXR-β) was examined by immunohistochemistry (IHC) on tissue microarrays comprising benign and malignant thyroid tissues.

RESULTS

Across all groups of benign and malignant thyroid tissue, there was prominent expression of LXR-β and ROR-γ. Key findings in PTC were marked overexpression of RXR-γ and Rev-erbα compared to MNG. Within the PTC cohort, when BRAF(V600E) tumors were compared with wild type BRAF, there was relative upregulation of RXR-γ and Rev-erbα and downregulation of AR, ERR-γ, and ROR-γ. In FC, EAR-2 was overexpressed, while PPAR-α and PPAR-δ were underexpressed compared to MNG. The NR expression profile of HCC was distinct, characterized by significant downregulation of a wide range of NRs. IHC for Rev-erbα and LXR-β localized protein expression to the tumor cells. Moderate to strong Rev-erbα immunostaining was seen in 22 out of 23 PTC, and, overall, staining was stronger than in the benign group.

CONCLUSIONS

These results represent the first systematic examination of NR expression in thyroid cancer. Our finding of tumor-specific patterns of NR expression, as well as significant differences in NR expression between BRAF(V600E) and wild type BRAF PTC, provides a basis for further mechanistic studies and highlights potential novel therapeutic targets for this malignancy.

Significance of allelic percentage of BRAF c.1799T > A (V600E) mutation in papillary thyroid carcinoma

BACKGROUND

Somatic BRAF mutation is frequently observed in papillary thyroid carcinoma (PTC). Recent evidence suggests that PTCs are heterogeneous tumors containing a subclonal or oligoclonal occurrence of BRAF mutation. Conflicting results have been reported concerning the prognostic significance of the mutant allele frequency. Our present aim was to investigate the association between the percentage of BRAF c.1799T > A (p.Val600Glu) alleles and clinicopathological parameters in PTC.

METHODS

Genomic DNA was extracted from fresh-frozen specimens obtained from 50 PTC patients undergoing total thyroidectomy. The BRAF mutation status was determined by Sanger sequencing. The percentage of mutant BRAF alleles was quantified by mass spectrometric genotyping, pyrosequencing, and competitive allele-specific TaqMan PCR (castPCR).

RESULTS

Positive rate of BRAF mutation was 72 % by Sanger sequencing, 82 % by mass spectrometric genotying, and 84 % by pyrosequencing or castPCR. The average percentage of mutant BRAF alleles was 22.5, 31, and 30.7 %, respectively. There was a good correlation among three quantification methods (Spearman's rho = 0.87-0.97; p < 0.0001). The mutant allele frequency was significantly correlated with tumor size (rho = 0.47-0.52; p < 0.01) and extrathyroidal invasion. The frequency showed no difference in pathological lymph node metastasis.

CONCLUSIONS

The percentage of mutant BRAF alleles is positively associated with tumor burden and extrathyroidal invasion in PTC. Relatively good correlations exist among mass spectrometric genotyping, pyrosequencing, and castPCR in quantification of mutant BRAF allele frequency.

Differentiated thyroid cancer: a new perspective with radiolabeled somatostatin analogues for imaging and treatment of patients

BACKGROUND

The expression of somatostatin receptors (SSTR) in thyroid cells may offer the possibility to identify metastatic lesions and to select patients for peptide receptor radionuclide therapy (PRRT). We investigated (68)Ga-DOTATOC positron emission tomography/computed tomography (PET/CT) to select patients with progressive differentiated thyroid cancer (DTC) for PRRT as well as treatment response and toxicity in treated patients.

METHODS

We enrolled 41 patients with progressive radioiodine-negative DTC (24 women and 17 men; mean age=54.3 years, median=59 years, range=19-78 years). In all patients, [(18)F]FDG-PET/CT was performed to determine recurrent disease with enhanced glucose metabolism, and (68)Ga-DOTATOC PET/CT was used to identify SSTR expression. Dosimetric evaluation was performed with (111)In-DOTATOC scintigraphy. Eleven patients were treated with PRRT receiving a fractionated injection of 1.5-3.7 GBq (90)Y-DOTATOC/administration. Serial (68)Ga-DOTATOC PET/CT scans were performed in all treated patients to evaluate treatment response. Parameters provided by (68)Ga-DOTATOC PET/CT were analyzed as potential therapeutic predictors to differentiate responding from nonresponding. In all treated patients, adverse events and toxicity were recorded.

RESULTS

(68)Ga-DOTATOC PET/CT were positive in 24/41 of radioiodine-negative DTC patients. Based on the high expression of SSTR detected by (68)Ga-DOTATOC PET/CT, 13 patients were suitable for PRRT. Two out of 13 patients were not treated due to the lack of fulfillment of other study inclusion criteria. PRRT induced disease control in 7/11 patients (two partial response and five stabilization) with a duration of response of 3.5-11.5 months. Objective response was associated with symptoms relief. Functional volume (FV) over time obtained by PET/CT was the only parameter demonstrating a significant difference between lesions responding and nonresponding to PRRT (p=0.001). Main PRRT adverse events were nausea, asthenia, and transient hematologic toxicity. One patient experienced permanent renal toxicity.

CONCLUSIONS

In our series, SSTR imaging provided positive results in more than half of the cases with radioiodine-negative DTC, and about one third of patients were eligible for PRRT. (68)Ga-DOTATOC PET/CT seems a reliable tool both for patient selection and evaluation of treatment response. In our experience, FV determination over time seems to represent a reliable parameter to determine tumor response to PRRT, although further investigations are needed to better define its role.

New therapeutic options for advanced forms of thyroid cancer

INTRODUCTION

While the vast majority of patients with thyroid cancer have an excellent prognosis, those with more aggressive courses experience significant morbidity and mortality. Advanced forms of thyroid cancer are typically refractory to standard therapy. Numerous agents with potential usefulness in the treatment of advanced thyroid cancer have recently come under study.

AREAS COVERED

This article reviews agents identified through a systematic review of the scientific literature as being under investigation for treatment of advanced thyroid cancer. A search of both PubMed and the NCI Clinical Trials website was performed to identify such agents having reached Phase II or III testing. Improved understanding of cancer cell signaling pathways has led to the identification of > 500 kinases as potential therapeutic targets. Additional agents of interest include those that inhibit neoangiogenesis, alter epigenetic factors or stimulate antitumor immune reactions. While presently available agents have shown promise in improving progression-free survival (PFS), complete responses are not seen and significant adverse side effects are encountered.

EXPERT OPINION

The development of numerous new anticancer agents holds the promise of treatment regimens that will extend PFS and ultimately overall survival in patients with advanced thyroid cancer. Anticipated future developments include individualized, multimodal treatment regimens based on specific tumor cell biology and driver mutations.

CD3(-)CD16(-)CD56(bright) immunoregulatory NK cells are increased in the tumor microenvironment and inversely correlate with advanced stages in patients with papillary thyroid cancer

BACKGROUND

The innate immune system is the first line of defense and plays a key role in thyroid cancer development. The role of the tumor-infiltrating natural killer (NK) cells is becoming increasingly important in research and potential cancer therapies. NK cell subpopulations, CD3(-)CD16(+)CD56(dim) and CD3(-)CD16(-)CD56(bright), demonstrate a significant role in the tumor immuno-surveillance process.

METHODS

We investigated the distribution of CD3(-)CD16(+)CD56(dim) and CD3(-)CD16(-)CD56(bright) NK subpopulations in tissue and blood samples from patients with papillary thyroid cancer (PTC) and nodular goiter (NG). Twenty-eight patients with PTC, 13 patients with NG, and 50 healthy donors were included in the study. Tissue and blood samples from all patients and blood samples from healthy donors were analyzed for CD3(-)CD16(+)CD56(dim) and CD3(-)CD16(-)CD56(bright) NK cells by flow cytometry.

RESULTS

A significant predominance of CD3(-)CD16(+)CD56(dim) cells compared to CD3(-)CD16(-)CD56(bright) NK cells was found in blood samples in all groups (p<0.0001 in PTC, NG, and healthy donors). Increased infiltration by CD3(-)CD16(-)CD56(bright) NK cells was observed in thyroid tissue of patients with PTC, as compared to CD3(-)CD16(+)CD56(dim) NK cells (p=0.046), while CD3(-)CD16(+)CD56(dim) NK cells demonstrated a higher infiltration of NG tissues. CD3(-)CD16(+)CD56(dim) NK cell tissue infiltration positively correlated with advanced stages of PTC. In contrast, the CD3(-)CD16(-)CD56(bright) NK cell population was negatively associated with tumor stage in patients with PTC.

CONCLUSION

CD3(-)CD16(-)CD56(bright) NK cell infiltration seems to be associated with PTC progression. These findings contribute to a better understanding of the immune response in PTC and may lead to novel immunotherapeutic approaches in these patients.

Translational research in endocrine surgery

This article reviews translational research in endocrine surgery, with a focus on disorders of the thyroid, parathyroids, adrenals, and endocrine pancreas. Discovery of genes responsible for heritable endocrine cancer syndromes has increased knowledge of the causes and mechanisms of endocrine cancer and has refined surgical treatment options. Knowledge of mutations in sporadic cancer has led to rapid progress in small-molecule kinase inhibitor strategies. These breakthroughs and their influence on current therapy are discussed to provide surgeons with an overview of the basic science research currently creating new clinical treatments and improving patient care.

Vitamin D in thyroid tumorigenesis and development

Besides its classical role in bone and calcium homeostasis, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), the active form of vitamin D, has many non-classical effects; antiproliferative, anti-apoptotic and prodifferentiating effects of 1,25(OH)2D3 have been described in several tumour types in preclinical models. This review focuses on the insights gained in the elucidation of the role of 1,25(OH)2D3 in the normal thyroid and in the pathogenesis, progression and treatment of thyroid cancer, the most common endocrine malignancy. An increasing amount of observations points towards a role for impaired 1,25(OH)2D3-VDR signalling in the occurrence and progression of thyroid cancer, and a potential for structural analogues in the multimodal treatment of dedifferentiated iodine-resistant thyroid cancer. A role for vitamin D in thyroid-related autoimmunity is less convincing and needs further study. Altered 1,25(OH)2D3-VDR signalling does not influence normal thyroid development nor thyrocyte function, but does affect C-cell function, at least in rodents. If these findings also apply to humans deserves further study.

Treatment of advanced medullary thyroid cancer

Therapy decisions in advanced medullary thyroid carcinoma should be guided by a critical appraisal of the natural disease course (slowly progressive vs. aggressive) and benefits and side effects of therapy. Therapy goals should be distinguished between curative and palliative. Local treatments are mainly palliative and may add to quality of life. The advent of novel systemic therapies opens promising perspectives but its place in the therapeutic arsenal must be further determined.

Long-term analysis of the efficacy and tolerability of sorafenib in advanced radio-iodine refractory differentiated thyroid carcinoma: final results of a phase II trial

OBJECTIVE

We conducted a prospective phase II clinical trial to determine the efficacy of sorafenib in patients with advanced radio-iodine refractory differentiated thyroid cancer. In this article, the long-term results are presented.

PATIENTS AND METHODS

Thirty-one patients with progressive metastatic or locally advanced radioactive iodine refractory differentiated thyroid cancer received sorafenib 400 mg orally twice daily. The study end points included response rate, progression-free survival (PFS), overall survival (OS), best response by Response Evaluation Criteria in Solid Tumors criteria 1.0, and toxicity.

RESULTS

Median PFS was 18 months (95% confidence interval (95% CI): 7-29 months) and median OS was 34.5 months (95% CI: 19-50 months). Eight patients (31%) achieved a partial response and 11 patients (42%) showed stable disease after a median follow-up of 25 months (range 3.5-39 months). Toxicity mostly included hand foot syndrome, weight loss, diarrhea, and rash.

CONCLUSION

Sorafenib has clinically relevant antitumor activity in patients with progressive metastatic or locally advanced radio-iodine refractory differentiated thyroid cancer. Sorafenib can nowadays be considered as the standard option in these patients.

CD133-expressing thyroid cancer cells are undifferentiated, radioresistant and survive radioiodide therapy

Purpose

¹³¹I therapy is regularly used following surgery as a part of thyroid cancer management. Despite an overall relatively good prognosis, recurrent or metastatic thyroid cancer is not rare. CD133-expressing cells have been shown to mark thyroid cancer stem cells that possess the characteristics of stem cells and have the ability to initiate tumours. However, no studies have addressed the influence of CD133-expressing cells on radioiodide therapy of the thyroid cancer. The aim of this study was to investigate whether CD133⁺ cells contribute to the radioresistance of thyroid cancer and thus potentiate future recurrence and metastasis.

Methods

Thyroid cancer cell lines were analysed for CD133 expression, radiosensitivity and gene expression.

Results

The anaplastic thyroid cancer cell line ARO showed a higher percentage of CD133⁺ cells and higher radioresistance. After γ-irradiation of the cells, the CD133⁺ population was enriched due to the higher apoptotic rate of CD133⁻ cells. In vivo ¹³¹I treatment of ARO tumour resulted in an elevated expression of CD133, Oct4, Nanog, Lin28 and Glut1 genes. After isolation, CD133⁺ cells exhibited higher radioresistance and higher expression of Oct4, Nanog, Sox2, Lin28 and Glut1 in the cell line or primarily cultured papillary thyroid cancer cells, and lower expression of various thyroid-specific genes, namely NIS, Tg, TPO, TSHR, TTF1 and Pax8.

Conclusion

This study demonstrates the existence of CD133-expressing thyroid cancer cells which show a higher radioresistance and are in an undifferentiated status. These cells possess a greater potential to survive radiotherapy and may contribute to the recurrence of thyroid cancer. A future therapeutic approach for radioresistant thyroid cancer may focus on the selective eradication of CD133⁺ cells.