Discovery of metastases in thyroid cancer and "benign metastasizing goiter": a historical note

At the beginning of the eighteenth century, most physicians recognized cancer as an aggressive process that gradually spreads, leading to cachexia and death. Thyroid malignancies had long been underestimated because the majority of the population of West Europe suffered from diffuse goiters that masked malignant processes in the neck. Moreover, the life expectancy at that time was very low (about 37-40 years), so the majority of people died of other causes before metastatic thyroid cancer could develop and manifest. Nevertheless, in 1817, French dermatologist Jean Louis Alibert described the first case of a malignant tumor involving the thyroid gland. From the 1820s the number of case reports describing thyroid cancer increased. Even though Jean Claude Recamier described metastases in 1829, secondary lesions on various organs in patients with thyroid malignancies were not themselves considered malignant until 1876.

Impaired Glucose Metabolism, Anti-Diabetes Medications, and Risk of Thyroid Cancer

Simple Summary

An epidemiologic link exists between obesity, insulin resistance, diabetes, and some cancers, such as breast cancer and colon cancer. The prevalence of obesity and diabetes is increasing, and additional epidemiologic data suggest that there may be a link between obesity and risk of thyroid abnormalities. Factors that may link obesity and diabetes with thyroid proliferative disorders include elevated circulating levels of insulin, increased body fat, high blood sugars, and exogenous insulin use. However, mechanisms underlying associations of obesity, diabetes, and thyroid proliferative disorders are not yet fully understood. The present manuscript reviews and summarizes current evidence of mechanisms and epidemiologic associations of obesity, insulin resistance, and use of anti-diabetes medications with benign and malignant proliferative disorders of the thyroid.

Abstract

The prevalence of obesity is progressively increasing along with the potential high risk for insulin resistance and development of type 2 diabetes mellitus. Obesity is associated with increased risk of many malignancies, and hyperinsulinemia has been proposed to be a link between obesity and cancer development. The incidence of thyroid cancer is also increasing, making this cancer the most common endocrine malignancy. There is some evidence of associations between obesity, insulin resistance and/or diabetes with thyroid proliferative disorders, including thyroid cancer. However, the etiology of such an association has not been fully elucidated. The goal of the present work is to review the current knowledge on crosstalk between thyroid and glucose metabolic pathways and the effects of obesity, insulin resistance, diabetes, and anti-hyperglycemic medications on the risk of thyroid cancer development.

Apolipoprotein CIII and Angiopoietin-like Protein 8 are Elevated in Lipodystrophy and Decrease after Metreleptin

Context

Lipodystrophy syndromes cause hypertriglyceridemia that improves with leptin treatment using metreleptin. Mechanisms causing hypertriglyceridemia and improvements after metreleptin are incompletely understood.

Objective

Determine relationship of circulating lipoprotein lipase (LPL) modulators with hypertriglyceridemia in healthy controls and in patients with lipodystrophy before and after metreleptin.

Methods

Cross-sectional comparison of patients with lipodystrophy (generalized lipodystrophy n = 3; partial lipodystrophy n = 11) vs age/sex-matched healthy controls (n = 28), and longitudinal analyses in patients before and after 2 weeks and 6 months of metreleptin. The study was carried out at the National Institutes of Health, Bethesda, Maryland. Outcomes were LPL stimulators apolipoprotein (apo) C-II and apoA-V and inhibitors apoC-III and angiopoietin-like proteins (ANGPTLs) 3, 4, and 8; ex vivo activation of LPL by plasma.

Results

Patients with lipodystrophy were hypertriglyceridemic and had higher levels of all LPL stimulators and inhibitors vs controls except for ANGPTL4, with >300-fold higher ANGPTL8, 4-fold higher apoC-III, 3.5-fold higher apoC-II, 1.9-fold higher apoA-V, 1.6-fold higher ANGPTL3 (P < .05 for all). At baseline, all LPL modulators except ANGPLT4 positively correlated with triglycerides. Metreleptin decreased apoC-II and apoC-III after 2 weeks and 6 months, and decreased ANGPTL8 after 6 months (P < 0.05 for all). Plasma from patients with lipodystrophy caused higher ex vivo LPL activation vs hypertriglyceridemic control plasma (P < .0001), which did not change after metreleptin.

Conclusion

Elevations in LPL inhibitors apoC-III and ANGPTL8 may contribute to hypertriglyceridemia in lipodystrophy, and may mediate reductions in circulating and hepatic triglycerides after metreleptin. These therefore are strong candidates for therapies to lower triglycerides in these patients.

A Combinatorial Strategy for Targeting BRAF V600E-Mutant Cancers with BRAFV600E Inhibitor (PLX4720) and Tyrosine Kinase Inhibitor (Ponatinib)

PURPOSE

Most aggressive thyroid cancers are commonly associated with a BRAF ^V600E mutation. Preclinical and clinical data in BRAF ^V600E cancers suggest that combined BRAF and MEK inhibitor treatment results in a response, but resistance is common. One mechanism of acquired resistance is through persistent activation of tyrosine kinase (TK) signaling by alternate pathways. We hypothesized that combination therapy with BRAF and multitargeting TK inhibitors (MTKI) might be more effective in BRAF ^V600E thyroid cancer than in single-agent or BRAF and MEK inhibitors.

EXPERIMENTAL DESIGN

The combined drug activity was analyzed to predict any synergistic effect using high-throughput screening (HTS) of active drugs. We performed follow-up in vitro and in vivo studies to validate and determine the mechanism of action of synergistic drugs.

RESULTS

The MTKI ponatinib and the BRAF inhibitor PLX4720 showed synergistic activity by HTS. This combination significantly inhibited proliferation, colony formation, invasion, and migration in BRAF ^V600E thyroid cancer cell lines and downregulated pERK/MEK and c-JUN signaling pathways, and increased apoptosis. PLX4720-resistant BRAF ^V600E cells became sensitized to the combination treatment, with decreased proliferation at lower PLX4720 concentrations. In an orthotopic thyroid cancer mouse model, combination therapy significantly reduced tumor growth (P < 0.05), decreased the number of metastases (P < 0.05), and increased survival (P < 0.05) compared with monotherapy and vehicle control.

CONCLUSIONS

Combination treatment with ponatinib and PLX4720 exhibited significant synergistic anticancer activity in preclinical models of BRAF ^V600E thyroid cancer, in addition to overcoming PLX4720 resistance. Our results suggest this combination should be tested in clinical trials.

MON-611 Biux2x2

Insulin is critical for lipid synthesis and inhibition of lipolysis. The dyslipidemia of type 2 diabetes (high triglycerides (TG), low HDL) is caused by selective IR with intact insulin signaling in lipogenic pathways. By contrast, knockout of all insulin signaling pathways due to insulin receptor (INSR) mutation leads to low TG and high HDL (in humans and mice), and decreased cholesterogenic gene expression, cholesterol and bile acid synthesis, PCSK9, and hepatic FFA flux (in liver INSR -/- mice). Thyroid hormone (TH) effects on lipids generally oppose those of insulin, and include increased lipolysis, FFA, and bile formation. We used patients with homozygous (-/-) and heterozygous (+/-) INSR mutations as models to understand interactions between TH and insulin action on lipids. Materials and methods: Euthyroid patients age 12-65y with proven INSR -/- (N=5) or +/- (N=2) mutation (22.2+6.5yr; 4 males) were treated with liothyronine (T3) for 2 weeks with peak target level 25-50% above upper limit of normal. Samples were obtained before and after T3 for thyroid hormones (TSH, fT4, TT4, fT3, TT3), lipids (total cholesterol, LDL, HDL, TG, number and size of lipid particles by NMR, ApoA1, ApoB), lipid regulating enzymes (CETP activity, LCAT activity and mass, PCSK9, PTPL, Lp-PLA2), lipolysis (glycerol turnover), and palmitate turnover. Results: After initiation of T3, hyperthyroid state was achieved by day 3 based on fT3 and TT3 with TSH suppression on day 4. On the standard lipid panel, TG decreased from 64.2 at baseline to 52.6mg/dl after T3 (p=.1), total cholesterol from 143±18.2 to 119.7±9.4mg/dl (p=.0009), LDL from 76.3±15.7 to 61.1±15.5mg/dl (p=.02), and HDL from 62.2±11.9 to 55.2±10.3mg/dl (p=.026). NMR analysis of lipoprotein particles showed that triglyceride-rich lipoprotein particles (TRLP) decreased from to 20±9.8 to 13±5.7 nmol/l (p=.06), LDLP from 1115±201 to 937±195 nmol/L (p=.016), large LDLP from 139±73 to 81±48 nmol/l (p=.046), size of the LDLP from 20.5±0.4 to 20.2±0.4 nm (p=.055), ApoB from 55.7±11 to 45.4±11 mg/dl (p=0.015), HDLP from 20±3 to 18.5±2 nm (p=.08), large HDLP from 3.6±1.9 to 2.8±1.8 umol/l (p=.06), size of HDLP particles from 9.5±0.6 to 9.4±0.6 nm (p=.08), and ApoA1 from 144±4 to 129±15 mg/dl (p=.02). No significant increase in FFA was seen after T3. Lipid enzymes were unchanged after T3 except for PLAC activity, which decreased from 128±30 to 111±28 nmol/min/ml (p=0.03). There was no difference in lipolysis or palmitate turnover rate after T3. In conclusion, we found that T3 had the expected effects on lipids in INSR mutation patients. No changes in key lipid enzymes were found after T3, perhaps due to small sample size. Further long-term studies are needed to determine long-term effects of TH on lipid metabolism in the setting of normal vs. impaired insulin signaling.

Genetic Tumor Syndromes with Endocrine Involvement: A Compendium and an Update

Many hereditary and sporadic tumor and other syndromes are associated with endocrine functional and or structural abnormalities. The last few decades have yielded advancements in the field with improvements in diagnostic testing, screening guidelines and novel treatment options. In general, endocrine functional abnormalities and neoplasms share an early age of onset. There remains room for improvement as limited literature exists regarding clinical course, prognosis, and screening for earlier cancer detection. This should allow for more timely intervention, and possibly improved outcomes. The aim of this article is to summarize the current knowledge about prevalence, clinical course, and prognosis of functional and structural pituitary, thyroid, adrenal, and gonadal abnormalities in patients with 17 known syndromic, mostly tumor-predisposing, diseases, wherever possible, we review screening recommendations.

Nelfinavir inhibits proliferation and induces DNA damage in thyroid cancer cells

The HIV protease inhibitor Nelfinavir (NFV) inhibits PI3K/AKT and MAPK/ERK signaling pathways, emerging targets in thyroid cancers. We examined the effects of NFV on cancer cells that derived from follicular (FTC), papillary (PTC) and anaplastic (ATC) thyroid cancers. NFV (1-20 µM) was tested in FTC133, BCPAP and SW1736 cell lines. The effects of NFV on cell proliferation were determined in vitro using real-time microscopy and by flow cytometry. DNA damage, apoptotic cell death and expression of molecular markers of epithelial-mesenchymal transition (EMT) were determined by Western blot and real-time PCR. Real-time imaging demonstrated that NFV (10 µM) increased the time required for the cell passage through the phases of cell cycle and induced DNA fragmentation. Growth inhibitory effects of NFV were associated with the accumulation of cells in G0/G1 phase, downregulation of cyclin D1 and cyclin-dependent kinase 4 (CDK4). NFV also induced the expression of γH2AX and p53BP1 indicating DNA damage. Treatment with NFV (20 µM) resulted in caspase-3 cleavage in all examined cells. NFV (20 µM) decreased the levels of total and p-AKT in PTEN-deficient FTC133 cells. NFV had no significant effects on total ERK and p-ERK in BRAF-positive BCPAP and SW1736 cells. NFV had no effects on the expression of EMT markers (Twist, Vimentin, E- and N-Cadherin), but inhibited the migration and decreased the abilities of thyroid cancer cells to survive in non-adherent conditions. We conclude that NFV inhibits proliferation and induces DNA damage in thyroid cancer cell lines. Our in vitro data suggest that NFV has a potential to become a new thyroid cancer therapeutic agent.

Repositioning therapy for thyroid cancer: new insights on established medications

Repositioning of established non-cancer pharmacotherapeutic agents with well-known activity and side-effect profiles is a promising avenue for the development of new treatment modalities for multiple cancer types. We have analyzed some of the medications with mechanism of action that may have relevance to thyroid cancer (TC). Experimental in vitro and in vivo evidences, as well as results of clinical studies, have indicated that molecular targets for medications currently available for the treatment of mood disorders, sexually transmitted diseases, metabolic disorders, and diabetes may be active and relevant in TC. For instance, the derivatives of cannabis and an anti-diabetic agent, metformin, both are able to inhibit ERK, which is commonly activated in TC cells. We present here several examples of well-known medications that have the potential to become new therapeutics for patients with TC. Repositioning of established medications for the treatment of TC could broaden the scope of current therapeutic strategies. These diverse treatment choices could allow physicians to provide an individualized approach to optimize treatment for patients with TC.

The HIV protease inhibitor nelfinavir down-regulates RET signaling and induces apoptosis in medullary thyroid cancer cells

CONTEXT

Mutations of RET tyrosine kinase are associated with the development of medullary thyroid cancer (MTC). The heat shock protein (HSP) 90 chaperone is required for folding and stability of RET mutants. HSP90 is a molecular target for the HIV protease inhibitor nelfinavir (NFV).

OBJECTIVE

We hypothesized that treatment with NFV may lead to the inhibition of RET signaling and induction of apoptosis in MTC cells.

DESIGN

Two human MTC cell lines, TT and MZ-CRC-1, which harbor endogenous C634W or M918T RET mutations, respectively, were exposed to clinically achievable concentrations of NFV. JC-1 staining and caspase-3 cleavage assays were performed to measure mitochondrial membrane potential and apoptosis. Activation of RET signaling was examined by Western blot. Autophagy was monitored by the detection of the light-chain 3BII. Expression of HSP90 and LC3B were examined in 36 human MTCs.

RESULTS

At a therapeutic serum concentration (10 μM), NFV inhibited the viability of TT and MZ-CRC-1 cells by 55% and 10%, respectively. In a dose-dependent manner, NFV inhibited cyclin D1 and caused caspase-3 cleavage. NFV decreased the level of RET protein and blocked the activation of RET downstream targets (phosphorylated ERK, phosphorylated AKT, and p70S6K/pS6). NFV induced metabolic stress, activated AMP-activated protein kinase and increased autophagic flux. Pharmacological inhibition of autophagy (chloroquine) augmented NFV-inducible cytotoxicity, suggesting that autophagy was protective in NFV-treated cells. NFV led to mitochondrial membrane depolarization and induced both oxidative stress and DNA damage. An antioxidant (n-acetylcysteine) attenuated DNA damage and prevented NFV-inducible apoptosis. HSP90 overexpression was found in 17 of 36 human MTCs and correlated with metastases and RET mutations. LC3B was detected in 20 of 36 human MTCs.

CONCLUSIONS

NFV has a wide spectrum of activity against MTC cells, and its cytotoxicity can be augmented by inhibiting autophagy. Expression of NFV molecular targets in metastatic MTC suggests that NFV has a potential to become a thyroid cancer therapeutic agent.

Abstract 2124: The HIV protease inhibitor Nelfinavir inhibits medullary thyroid cancer cell growth

Background. Medullary thyroid cancer (MTC) is associated with RET mutations and activation of PI3K/AKT and MEK/ERK signaling pathways. Heat shock protein 90 (HSP90) contributes to functional stabilization of PI3K/AKT signaling and is required for growth factor inducible activation of the MEK/ERK pathway. A recent study showed that HSP90 is a molecular target for HIV protease inhibitor Nelfinavir (NFV). Treatment with NFV is associated with growth inhibition and induction of apoptosis in breast, ovarian and prostate cancer cell lines. Objectives. We hypothesized that NFV-inducible inhibition of HSP90 would lead to down-regulation of PI3K/AKT and MAPK/ERK signaling pathways and induction of apoptosis in MTC cells. Methods. MTC-derived cells (TT cells) harboring the RET C634W mutation were treated with NFV at concentrations from 1μM to 10μM. Activation of MAPK/ERK and AKT/ mTOR/p70S6K/pS6 signaling was assessed by Western blot using specific phospho-antibodies. Apoptosis was determined by Western Blot with antibody against cleaved caspase 3. Cell growth and viability were determined by Vi-Cell analyzer and Alamar blue assay. HSP90 expression was examined in 12 human MTC tumor samples by immunostaining. HSP90 expression was correlated with pAKT and pERK level. Results. Treatment with NFV (1μM to 10μM for 48 hours) did not affect expression of HSP90 or levels of total AKT and ERK. In contrast, pAKT and pERK were inhibited in TT cells after treatment with NFV (5μM and 10 μM). Since both AKT and ERK pathways contribute to regulation of p70S6K/pS6 activity, we examined activation of this signaling axis. NFV (10μM) decreased the level of p-p70S6K, p-pS6 and down-regulated Cyclin D1. Growth experiments demonstrated that the number of viable cells decreased by 30% and 85% after treatment with NFV at concentration 5μM and 10μM, respectively. Microscopy showed that exposure to NFV was associated with cell rounding and nuclear fragmentation, suggesting induction of apoptosis. Western blot analysis revealed that NFV induced caspase 3 cleavage in TT cells. In addition, treatment with NFV was associated with induction of γH2AX, indicating DNA damage. Immunostaining of human MTC showed increased expression of HSP 90 in 5/12 of examined MTCs compared to corresponding normal thyroid tissue. The highest level of cytoplasmic HSP90 was detected in 3 cases of MTC harboring RET mutation, and co-localization staining showed that cells with high level of HSP90 expression also exhibited prominent pAKT and pERK. Conclusion. Treatment of MTC cell with clinically achievable concentrations of NFV results in down-regulation of AKT and ERK signaling and inhibition of MTC cell growth. Expression of HSP90 in human tumors suggests that it has a role in maintenance of anti-apoptotic signaling in MTC cells. Together these data support the potential utility of NFV for the treatment of patients with MTC.

Citation Format: Yevgeniya Kushchayeva, Aneeta Patel, John Costello, Vasyl Vasko, Nancy Carroll, Rubie Sue Jackson, Kenneth Burman, Lisa Boyle. The HIV protease inhibitor Nelfinavir inhibits medullary thyroid cancer cell growth. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2124. doi:10.1158/1538-7445.AM2013-2124

Percutaneous vertebroplasty for thyroid cancer metastases to the spine

BACKGROUND

Spinal metastases secondary to thyroid cancer of follicular and parafollicular cell origin are uncommon but may require stabilization of the compromised vertebrae to prevent fracture with spinal cord injury. Such treatment may also relieve pain and improve survival and quality of life.

SUMMARY

Percutaneous vertebroplasty (PV) is a minimally invasive, radiologically guided procedure whereby bone cement is injected into a structurally weakened vertebra to provide immediate stability. The authors present two cases of thyroid cancer with spinal metastases. Both patients successfully underwent PV. Following PV, the patients experienced significant pain relief with immediate reduction in analgesic requirements and improvement in other symptoms. Both were able to return to their daily activities.

CONCLUSION

PV is a minimally invasive spinal procedure and should be considered for patients with metastatic thyroid cancer with spinal metastases.

Prognostic Indications for H�rthle Cell Cancer

Hürthle cell carcinoma (HCC) has been reported to have variable clinical behavior. The objective of this study was to determine the important prognostic factors in patients with HCC. It was a retrospective investigation of 33 patients with HCC treated in our institution from 1976 to 2002. The average age of our 33 patients with HCC was 55.2 years (range 20-82 years; 23 women, 10 men). Fifteen patients (45.5%) presented with a T2 tumor, 7 (21.2%) with a T3 tumor, and 8 (24.2%) with a T4 tumor; the tumor stage was unknown in three patients. Coexisting papillary carcinoma occurred in six patients (18%), 9% of whom presented with metastatic disease. Twelve patients (36.4%) had metastases, four of whom (12.2%) had persistent HCC, and 8 (24.2%) developed recurrent HCC (range 1-9 years). Eight of these twelve patients (66.7%) died from the HCC. The average follow-up time was 5.5 years (range 1-16 years). Altogether, 3 of 23 women and 5 of 10 men died from their HCC ( p < 0.05). Of the 22 patients with T2-T3 tumors, 5 (22.7%) developed metastases and 1 patient died; 5 of 8 patients (62.5%) with T4 tumors developed metastases and died ( p < 0.01). Patients who were treated by less than total thyroidectomy had a worse prognosis by univariate analysis ( p < 0.01) but not by multivariate analysis. Survival time for patients with persistent disease was shorter than for those with recurrent disease ( p < 0.05). Multivariate analysis, however, revealed no difference for extent of operation or those with persistent and recurrent disease. The cause-specific survivals were 74% and 49% at 5 and 10 years, respectively. Disease-free survivals were 65.0% and 40.5% at 5 and 10 years, respectively. Our findings show that gender and stage of disease influence the prognosis of patients with HCC.