mTOR Pathway in Papillary Thyroid Carcinoma: Different Contributions of mTORC1 and mTORC2 Complexes for Tumor Behavior and SLC5A5 mRNA Expression

Pathogenesis and signaling pathways related to iodine-refractory differentiated thyroid cancer

Thyroid cancer is the most common malignant neoplasm within the endocrine system and the field of head and neck surgery. Although the majority of thyroid cancers, more than 90%, are well-differentiated thyroid carcinomas with a favourable prognosis, the escalating incidence of this disease has contributed to an increasing number of patients with a propensity for recurrent disease, rapid disease progression, and poor or no response to conventional treatments. These clinical challenges are commonly attributed to alterations in key thyroid oncogenes or signaling pathways, thereby initiating tumour cell dedifferentiation events, accompanied by reduced or virtually absent expression of the sodium/iodine symporter (NIS). As a result, the disease evolves into iodine-refractory differentiated thyroid cancer (RAIR-DTC), an entity that is insensitive to conventional radioiodine therapy. Despite being classified as a differentiated thyroid cancer, RAIR-DTC has an extremely poor clinical prognosis, with a 10-year survival rate of less than 10%. Therefore, it is of paramount importance to comprehensively elucidate the underlying pathogenesis of RAIR-DTC and provide specific targeted interventions. As the pathogenic mechanisms of RAIR-DTC remain elusive, here we aim to review recent advances in understanding the pathogenesis of RAIR-DTC and provide valuable insights for the development of future molecularly targeted therapeutic approaches.

Current Application of Nanoparticle Drug Delivery Systems to the Treatment of Anaplastic Thyroid Carcinomas

Anaplastic thyroid carcinomas (ATCs) are a rare subtype of thyroid cancers with a low incidence but extremely high invasiveness and fatality. The treatment of ATCs is very challenging, and currently, a comprehensive individualized therapeutic strategy involving surgery, radiotherapy (RT), chemotherapy, BRAF/MEK inhibitors (BRAFi/MEKi) and immunotherapy is preferred. For ATC patients in stage IVA/IVB, a surgery-based comprehensive strategy may provide survival benefits. Unfortunately, ATC patients in IVC stage barely get benefits from the current treatment. Recently, nanoparticle delivery of siRNAs, targeted drugs, cytotoxic drugs, photosensitizers and other agents is considered as a promising anti-cancer treatment. Nanoparticle drug delivery systems have been mainly explored in the treatment of differentiated thyroid cancer (DTC). With the rapid development of drug delivery techniques and nanomaterials, using hybrid nanoparticles as the drug carrier to deliver siRNAs, targeted drugs, immune drugs, chemotherapy drugs and phototherapy drugs to ATC patients have become a hot research field. This review aims to describe latest findings of nanoparticle drug delivery systems in the treatment of ATCs, thus providing references for the further analyses.

Customizing cancer treatment at the nanoscale: a focus on anaplastic thyroid cancer therapy

Anaplastic thyroid cancer (ATC) is a rare but highly aggressive kind of thyroid cancer. Various therapeutic methods have been considered for the treatment of ATC, but its prognosis remains poor. With the advent of the nanomedicine era, the use of nanotechnology has been introduced in the treatment of various cancers and has shown great potential and broad prospects in ATC treatment. The current review meticulously describes and summarizes the research progress of various nanomedicine-based therapeutic methods of ATC, including chemotherapy, differentiation therapy, radioiodine therapy, gene therapy, targeted therapy, photothermal therapy, and combination therapy. Furthermore, potential future challenges and opportunities for the currently developed nanomedicines for ATC treatment are discussed. As far as we know, there are few reviews focusing on the nanomedicine of ATC therapy, and it is believed that this review will generate widespread interest from researchers in a variety of fields to further expedite preclinical research and clinical translation of ATC nanomedicines.

Advances in the molecular mechanism and targeted therapy of radioactive-iodine refractory differentiated thyroid cancer

Most patients with differentiated thyroid cancer have a good prognosis after radioactive iodine-131 treatment, but there are still a small number of patients who are not sensitive to radioiodine treatment and may subsequently show disease progression. Therefore, radioactive-iodine refractory differentiated thyroid cancer treated with radioiodine usually shows reduced radioiodine uptake. Thus, when sodium iodine symporter expression, basolateral membrane localization and recycling degradation are abnormal, radioactive-iodine refractory differentiated thyroid cancer may occur. In recent years, with the deepening of research into the pathogenesis of this disease, an increasing number of molecules have become or are expected to become therapeutic targets. The application of corresponding inhibitors or combined treatment regimens for different molecular targets may be effective for patients with advanced radioactive-iodine refractory differentiated thyroid cancer. Currently, some targeted drugs that can improve the progression-free survival of patients with radioactive-iodine refractory differentiated thyroid cancer, such as sorafenib and lenvatinib, have been approved by the FDA for the treatment of radioactive-iodine refractory differentiated thyroid cancer. However, due to the adverse reactions and drug resistance caused by some targeted drugs, their application is limited. In response to targeted drug resistance and high rates of adverse reactions, research into new treatment combinations is being carried out; in addition to kinase inhibitor therapy, gene therapy and rutin-assisted iodine-131 therapy for radioactive-iodine refractory thyroid cancer have also made some progress. Thus, this article mainly focuses on sodium iodide symporter changes leading to the main molecular mechanisms in radioactive-iodine refractory differentiated thyroid cancer, some targeted drug resistance mechanisms and promising new treatments.

Clinical Implications of mTOR Expression in Papillary Thyroid Cancer—A Systematic Review

Papillary thyroid cancer (PTC) comprises approximately 80% of all thyroid malignancies. Although several etiological factors, such as age, gender, and irradiation, are already known to be involved in the development of PTC, the genetics of cancerogenesis remain undetermined. The mTOR pathway regulates several cellular processes that are critical for tumorigenesis. Activated mTOR is involved in the development and progression of PTC. Therefore, we performed a systematic review of papers studying the expression of the mTOR gene and protein and its relationship with PTC risk and clinical outcome. A systematic literature search was performed using PubMed, Embase, and Scopus databases (the search date was 2012–2022). Studies investigating the expression of mTOR in the peripheral blood or tissue of patients with PTC were deemed eligible for inclusion. Seven of the 286 screened studies met the inclusion criteria for mTOR gene expression and four for mTOR protein expression. We also analyzed the data on mTOR protein expression in PTC. We analyzed the association of mTOR expression with papillary thyroid cancer clinicopathological features, such as the TNM stage, BRAF V600E mutation, sex distribution, lymph node and distant metastases, and survival prognosis. Understanding specific factors involved in PTC tumorigenesis provides opportunities for targeted therapies. We also reviewed the possible new targeted therapies and the use of mTOR inhibitors in PTC. This topic requires further research with novel techniques to translate the achieved results to clinical application.

Aurora kinase a promotes the progression of papillary thyroid carcinoma by activating the mTORC2-AKT signalling pathway

BACKGROUND

Treatment failure is the main cause of death from papillary thyroid carcinoma (PTC). It is urgent to look for new intervention targets and to develop new therapies for treating PTC. Aurora-A kinase (AURKA) functionally regulates cell mitosis and is closely related to the occurrence and development of a variety of tumours. However, the expression and potential functions of AURKA in PTC remain largely elusive.

RESULTS

Clinicopathologically, AURKA is highly expressed in PTC tissues compared to normal tissues and is correlated with lymph node metastasis, TNM stage and patient prognosis. Biologically, AURKA functions as an oncoprotein to promote the proliferation and migration of PTC cells. Mechanistically, AURKA directly binds to SIN1 and compromises CUL4B-based E3 ligase-mediated ubiquitination and subsequent degradation of SIN1, leading to hyperactivation of the mTORC2-AKT pathway in PTC cells.

CONCLUSIONS

We found that AURKA plays critical roles in regulating the progression of PTC by activating the mTORC2-AKT pathway, highlighting the potential of targeting AURKA to treat PTC.

Research on a Weighted Gene Co-expression Network Analysis method for mining pathogenic genes in thyroid cancer

Thyroid cancer (TC) is one of the most common thyroid malignancies occurring worldwide, and accounts for about 1% of all the malignant tumors. It is one of the fastest growing tumor and can occur at any age, but it is more common in women. It is important to find the pathogenesis and treatment targets of TC. In this pursuit, the present study was envisaged to investigate the effective carcinogenic biological macromolecules, so as to provide a better understanding of the occurrence and development of TC. The clinical and gene expression data were collected from The Cancer Genome Atlas (TCGA). We clustered mRNA and long non-coding RNA (lncRNA) into different modules by Weighted Gene Co-expression Network Analysis (WGCNA), and calculated the correlation coefficient between the genes and clinical phenotypes. Using WGCNA, we identified the module with the highest correlation coefficient. Subsequently, by using the differential genes expression analysis to screen the differential micro-RNA (miRNA), the univariate Cox proportional hazard regression was employed to screen the hub genes related to overall survival (OS), with P < 0.05 as the statistical significance threshold. Finally, we designed a hub competitive endogenous RNA(ceRNA) network of disease-associated lncRNAs, miRNAs, and mRNAs. From the results of enrichment analysis, the association of these genes could be related to the occurrence and development of TC, and these hub RNAs can be valuable prognostic markers and therapeutic targets in TC.

p-S6 as a Prognostic Biomarker in Canine Oral Squamous Cell Carcinoma

Scarce information exists on the role of mTOR pathway proteins and their association to aggressiveness and prognosis of patients with canine oral cancers. We aimed to investigate the activated form of mTOR and its downstream S6 protein in canine oral squamous cell carcinoma (OSCC), and to evaluate potential associations between protein expression and clinic-pathologic variables and survival. For that we analysed p-mTOR and p-S6 protein expression by immunohistochemistry in 61 canine OSCCs. Multivariate analysis was conducted to examine their role in patients’ cancer-specific survival (CSS). p-mTOR and p-S6 expression were present in almost all cases. High-expression of p-mTOR was observed in 44 (72.1%) cases using extent score and 52 (85.2%) cases using intensity score. For p-S6, high expression was observed in 53 (86.9%) cases using extent score and in 54 (88.5%) cases using intensity score. An independent prognostic value for p-S6 extension (p = 0.027), tumour stage (p = 0.013) and treatment (p = 0.0009) was found in patients’ CSS analysis. Our data suggest that p-mTOR and p-S6 proteins are commonly expressed in canine OSCC and p-S6 expression is correlated with poor CSS in dogs with OSCC. More studies should be performed to identify possible therapeutic targets related with mTOR pathway for these patients.

Expression Profile and Diagnostic Significance of MicroRNAs in Papillary Thyroid Cancer

The incidence of papillary thyroid cancer (PTC) has increased in recent years. To improve the diagnostic management of PTC, we propose the use of microRNAs (miRNAs) as a biomarker. Our aim in this study was to evaluate the miRNA expression pattern in PTC using NanoString technology. We identified ten miRNAs deregulated in PTC compared with reference tissue: miR-146b-5p, miR-221-3p, miR-221-5p, miR-34-5p, miR-551b-3p, miR-152-3p, miR-15a-5p, miR-31-5p, and miR-7-5p (FDR < 0.05; |fold change (FC)| ≥ 1.5). The gene ontology (GO) analysis of differentially expressed miRNA (DEM) target genes identified the predominant involvement of epidermal growth factor receptor (EGFR), tyrosine kinase inhibitor resistance, and pathways in cancer in PTC. The highest area under the receiver operating characteristic (ROC) curve (AUC) for DEMs was found for miR-146-5p (AUC = 0.770) expression, indicating possible clinical applicability in PTC diagnosis. The combination of four miRNAs (miR-152-3p, miR-221-3p, miR-551b-3p, and miR-7-5p) showed an AUC of 0.841. Validation by real-time quantitative polymerase chain reactions (qRT-PCRs) confirmed our findings. The introduction of an miRNA diagnostic panel based on the results of our study may help to improve therapeutic decision making for questionable cases. The use of miRNAs as biomarkers of PTC may become an aspect of personalized medicine.

Molecular diagnosis and targeted treatment of advanced follicular cell-derived thyroid cancer in the precision medicine era

Most malignant thyroid tumours are initially treated with surgery or a combination of surgery and radioactive iodine (RAI) therapy. However, in patients with metastatic disease, many tumours become refractory to RAI, and these patients require alternative treatments, such as locoregional therapies and/or systemic treatment with multikinase inhibitors. Improvements in our understanding of the genetic alterations that occur in thyroid cancer have led to the discovery of several targeted therapies with clinical efficacy. These alterations include NTRK (neurotrophic tyrosine receptor kinase) gene fusions, with the tropomyosin receptor kinase inhibitors larotrectinib and entrectinib both approved by the European Medicines Agency and in other markets worldwide. Inhibitors of aberrant proteins resulting from alterations in RET (rearranged during transfection) and BRAF (B-Raf proto-oncogene) have also shown promising efficacy, and so far have received approval by the US Food and Drug Administration. Selpercatinib, a RET kinase inhibitor, was approved for use in Europe in early 2021. With the discovery of multiple actionable targets, it is imperative that effective testing strategies for these genetic alterations are integrated into the diagnostic armamentarium to ensure that patients who could potentially benefit from targeted treatments are identified. In this review, we offer our recommendations on the optimal testing strategies for detecting genetic alterations in thyroid cancer that have the potential to be targeted by molecular therapy. We also discuss the future of treatments for thyroid cancers, including the use of immune checkpoint inhibitors, and new generations of targeted treatments that are being developed to counter acquired tumour resistance.

MiR-7-5p inhibits thyroid cell proliferation by targeting the EGFR/MAPK and IRS2/PI3K signaling pathways

The aberrant expression of miRNAs is often correlated to tumor development. MiR-7-5p is a recently discovered downregulated miRNA in thyroid papillary carcinoma (PTC). The goal of this project was to characterize its functional role in thyroid tumorigenesis and to identify the targeted modulated pathways. MiR-7-5p overexpression following transfection in TPC1 and HT-ori3 cells decreased proliferation of the two thyroid cell lines. Analysis of global transcriptome modifications showed that miR-7-5p inhibits thyroid cell proliferation by modulating the MAPK and PI3K signaling pathways which are both necessary for normal thyroid proliferation and play central roles in PTC tumorigenesis. Several effectors of these pathways are indeed targets of miR-7-5p, among which EGFR and IRS2, two upstream activators. We confirmed the upregulation of IRS2 and EGFR in human PTC and showed the existence of a negative correlation between the decreased expression of miR-7-5p and the increased expression of IRS2 or EGFR. Our results thus support a tumor-suppressor activity of miR-7-5p. The decreased expression of miR-7-5p during PTC tumorigenesis might give the cells a proliferative advantage and delivery of miR-7-5p may represent an innovative approach for therapy.

Targeting EML4-ALK gene fusion variant 3 in thyroid cancer

Finding targetable gene fusions can expand the limited treatment options in radioactive iodine-refractory (RAI-r) thyroid cancer. To that end, we established a novel cell line 'JVE404' derived from an advanced RAI-r papillary thyroid cancer (PTC) patient, harboring an EML4-ALK gene fusion variant 3 (v3). Different EML4-ALK gene fusions can have different clinical repercussions. JVE404 cells were evaluated for cell viability and cell signaling in response to ALK inhibitors crizotinib, ceritinib and lorlatinib, in parallel to the patient's treatment. He received, after first-line lenvatinib, crizotinib (Drug Rediscovery Protocol (DRUP) trial), and lorlatinib (compassionate use). In vitro treatment with crizotinib or ceritinib decreased viability in JVE404, but most potently and significantly only with lorlatinib. Western blot analysis showed a near total decrease of 99% and 89%, respectively, in pALK and pERK expression levels in JVE404 cells with lorlatinib, in contrast to remaining signal intensities of a half and a third of control, respectively, with crizotinib. The patient had a 6-month lasting stable disease on crizotinib, but progressive disease occurred, including the finding of cerebral metastases, at 8 months. With lorlatinib, partial response, including clinical cerebral activity, was already achieved at 11 weeks' use and ongoing partial response at 7 months. To our best knowledge, this is the first reported case describing a patient-specific targeted treatment with lorlatinib based on an EML4-ALK gene fusion v3 in a thyroid cancer patient, and own cancer cell line. Tumor-agnostic targeted therapy may provide valuable treatment options in personalized medicine.

Molecular mechanisms of radioactive iodine refractoriness in differentiated thyroid cancer: Impaired sodium iodide symporter (NIS) expression owing to altered signaling pathway activity and intracellular localization of NIS

The advanced, metastatic differentiated thyroid cancers (DTCs) have a poor prognosis mainly owing to radioactive iodine (RAI) refractoriness caused by decreased expression of sodium iodide symporter (NIS), diminished targeting of NIS to the cell membrane, or both, thereby decreasing the efficacy of RAI therapy. Genetic aberrations (such as BRAF, RAS, and RET/PTC rearrangements) have been reported to be prominently responsible for the onset, progression, and dedifferentiation of DTCs, mainly through the activation of mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/AKT signaling pathways. Eventually, these alterations result in a lack of NIS and disabling of RAI uptake, leading to the development of resistance to RAI therapy. Over the past decade, promising approaches with various targets have been reported to restore NIS expression and RAI uptake in preclinical studies. In this review, we summarized comprehensive molecular mechanisms underlying the dedifferentiation in RAI-refractory DTCs and reviews strategies for restoring RAI avidity by tackling the mechanisms.

Inherited Thyroid Tumors With Oncocytic Change

Familial non-medullary thyroid carcinoma (FNMTC) corresponds to 5-10% of all follicular cell-derived carcinoma (FCDTC). Oncocytic thyroid tumors have an increased incidence in the familial context in comparison with sporadic FCDTC, encompassing benign and malignant tumors in the same family presenting with some extent of cell oxyphilia. This has triggered the interest of our and other groups to clarify the oncocytic change, looking for genetic markers that could explain the emergence of this phenotype in thyroid benign and malignant lesions, focusing on familial aggregation. Despite some advances regarding the identification of the gene associated with retinoic and interferon-induced mortality 19 (GRIM-19), as one of the key candidate genes affected in the "Tumor with Cell Oxyphilia" (TCO) locus, most of the mutations follow a pattern of "private mutations", almost exclusive to one family. Moreover, no causative genetic alterations were identified so far in most families. The incomplete penetrance of the disease, the diverse benign and malignant phenotypes in the affected familial members and the variable syndromic associations create an additional layer of complexity for studying the genetic alterations in oncocytic tumors. In the present review, we summarized the available evidence supporting genomic-based mechanisms for the oncocytic change, particularly in the context of FNMTC. We have also addressed the challenges and gaps in the aforementioned mechanisms, as well as molecular clues that can explain, at least partially, the phenotype of oncocytic tumors and the respective clinico-pathological behavior. Finally, we pointed to areas of further investigation in the field of oncocytic (F)NMTC with translational potential in terms of therapy.

AHNAK2 is a novel prognostic marker and correlates with immune infiltration in papillary thyroid cancer: Evidence from integrated analysis

Papillary thyroid cancer (PTC) is the most prevalent endocrine tumor, and its incidence is still increasing. The mechanisms of PTC dedifferentiation and malignant progression remain unclear. In this study, we identified AHNAK2 as a key gene in PTC by differential expression analysis among four GEO datasets and validated its overexpression profile by data from the Oncomine, TCGA, and HPA databases and IHC staining analysis. AHNAK2 upregulation significantly correlated with advanced grades, stages, and lymph node events. Survival analysis suggested that AHNAK2 overexpression was coupled with poor overall survival. The immune infiltration analysis by TIMER and CIBERSORT indicated that AHNAK2 expression tightly correlated with the infiltration of diverse immune cell types, especially T cell subtypes. In addition, AHNAK2 is correlated with the expression of other conventional key genes of TC, such as PIK3CA, MAPK1, CTNNB1, and SLC5A5. AHNAK2 may be a novel prognostic marker for PTC.

PLEKHS1 Over-Expression is Associated with Metastases and Poor Outcomes in Papillary Thyroid Carcinoma

Pleckstrin homology domain containing S1 (PLEKHS1) is a poorly characterized factor, although its promoter mutations were identified in human malignancies including thyroid carcinoma (TC). This study was designed to determine PLEKHS1 promoter hotspot mutations in papillary and anaplastic thyroid carcinomas (PTCs and ATCs) and to evaluate if PLEKHS1 expression influences clinical outcome. The PLEKHS1 promoter mutation was observed in 1/93 of PTCs and none of 18 ATCs in our cohort; however, PLEKHS1 expression was aberrantly up-regulated in TCs compared to adjacent non-tumorous thyroid tissues. ATC tumors, an undifferentiated TC, exhibited the highest PLEKHS1 expression. In both TCGA and present cohorts of PTCs, PLEKHS1 gene methylation density was inversely correlated with its mRNA expression and demethylation at the PLEKHS1 locus occurred at two CpGs. Higher PLEKHS1 expression was associated with lymph node and distant metastases, and shorter overall and disease-free survival in our cohort of PTC patients. Importantly, PLEKHS1 over-expression predicted shorter patient survival in PTCs lacking TERT promoter mutations. Cellular experiments showed that PLEKHS1 over-expression enhanced AKT phosphorylation and invasiveness. Collectively, the PLEKHS1 gene demethylation causes its over-expression in PTCs. PLEKHS1 promotes aggressive behavior of TCs possibly by increasing AKT activity, and its over-expression predicts poor patient outcomes.

Down-Regulation of the Mammalian Target of Rapamycin (mTOR) Pathway Mediates the Effects of the Paeonol-Platinum(II) Complex in Human Thyroid Carcinoma Cells and Mouse SW1736 Tumor Xenografts

Background

This study aimed to investigate the effects of the paeonol-platinum(II) (PL-Pt[II]) complex on SW1736 human anaplastic thyroid carcinoma cell line and the BHP7-13 human thyroid papillary carcinoma cell line in vitro and on mouse SW1736 tumor xenografts in vivo.

Material/Methods

The cytotoxic effects of the PL-Pt(II) complex on SW1736 cells and BHP7-13 cells was measured using the MTT assay. Western blot measured the expression levels of cyclins, cell apoptotic proteins, and signaling proteins. DNA content and apoptosis were detected by flow cytometry. SW1736 cell thyroid tumor xenografts were established in mice followed by treatment with the PL-Pt(II) complex.

Results

Treatment of the SW1736 and BHP7-13 cells with the PL-Pt(II) complex reduced cell proliferation in a dose-dependent manner, with an IC50 of 1.25 μM and 1.0 μM, respectively, and increased the cell fraction in G0/G1phase, inhibited p53, cyclin D1, promoted p27 and p21 expression, and significantly increased the sub-G1 fraction. Treatment with the PL-Pt(II) complex increased caspase-3 degradation, reduced the expression of p-4EBP1, p-4E-BP1 and p-S6, and reduced the expression of p-ERK1/2 and p-AKT. Treatment with the PL-Pt(II) complex reduced the volume of the SW1736 mouse tumor xenografts on day 14 and day 21, and reduced AKT phosphorylation and S6 protein expression and increased degradation of caspase-3.

Conclusions

The cytotoxic effects of the PL-Pt(II) complex in human thyroid carcinoma cells, including activation of apoptosis and an increased sub-G1 cell fraction of the cell cycle, were mediated by down-regulation of the mTOR pathway.

Molecular Profiling of Follicular Variant of Papillary Thyroid Cancer

The molecular features of the follicular variant of papillary thyroid cancer are closely related to the clinical behavior of the tumor and the prognosis of the disease. BRAF-V600E mutations in patients with a follicular variant of papillary thyroid cancer have not been identified; however, the majority of patients had T3-4N0M0 stage of the disease. Changes in the expression of transcription and growth factors and AKT/m-TOR signaling pathway components were detected. In addition, hyperexpression of m-TOR and 4EBP1 kinases and CAIX enzyme was shown compared to the classical variant of papillary thyroid cancer, where an increase in the nuclear factor NF-κB p65 and c-RAF kinase expression was observed.

Effect of mesoporous silica nanoparticles co‑loading with 17‑AAG and Torin2 on anaplastic thyroid carcinoma by targeting VEGFR2

Anaplastic thyroid carcinoma (ATC) is a highly aggressive tumor with a poor prognosis and a low median survival rate because of insufficient effective therapeutic modalities. Recently, mesoporous silica nanoparticles (MSNs) as a green non-toxic and safe nanomaterial have shown advantages to be a drug carrier and to modify the targeting group to the targeted therapy. To aim of the study was to explore the effects of MSNs co-loading with 17-allylamino-17-demethoxy-geldanamycin (17-AAG; HSP90 inhibitor) and 9-(6-aminopyridin-3-yl)-1-(3-(trifluoromethyl)phenyl)benzo[h][1,6]naphthyridin-2(1H)-one (Torin2; mTOR inhibitor) by targeting vascular endothelial growth factor receptor 2 (VEGFR2) on the viability of human anaplastic thyroid carcinoma FRO cells. The cytotoxicity of 17-AAG and Torin2 were analyzed by MTT assay. The possible synergistic antitumor effects between 17-AAG and Torin2 were evaluated by CompuSyn software. Flow cytometry was performed to assess the VEGFR2 targeting of (17-AAG+Torin2)@MSNs-anti-VEGFR2 ab and uptake by FRO cells. An ATC xenograft mouse model was established to assess the antitumor effect of (17-AAG+Torin2)@MSNs-anti-VEGFR2 ab in vivo. The results revealed that the combination of 17-AAG and Torin2 inhibited the growth of FRO cells more effectively compared with single use of these agents. Additionally, the synergistic antitumor effect appeared when concentration ratio of the two drugs was 1:1 along with total drug concentration greater than 0.52 µM. Furthermore, in an ATC animal model, it was revealed that the (17-AAG+Torin2)@MSNs-anti-VEGFR2 ab therapy modality could most effectively prolong the median survival time [39.5 days vs. 33.0 days (non-targeted) or 27.5 days (control)]. Compared to (17-AAG+Torin2)@MSNs, the (17-AAG+Torin2)@MSNs-anti-VEGFR2 ab could not only inhibit ATC cell growth but also prolong the median survival time of tumor-bearing mice in vivo and vitro more effectively, which may provide a new promising therapy for ATC.

Relevant dose of the environmental contaminant, tributyltin, promotes histomorphological changes in the thyroid gland of male rats

Organotin compounds, such as tributyltin (TBT), are common environmental contaminants and suspected endocrine-disrupting chemicals. Tributyltin is found in antifouling paints, widely used in ships and other vessels. The present study evaluated whether a 15-day treatment with TBT at a dose of 100 ng/kg/day could induce histomorphological changes in the thyroid gland of rats. TBT promoted relevant alterations in the thyroid architecture, being the most relevant histological findings the presence of increased number of small-size follicles in the treated group. In qualitative analyses, colloid vacuolization, papillary budging structures, cystic degeneration and chronic thyroiditis, were observed. Moreover, histomorphometric analysis showed statistically significant changes in the follicular architecture of TBT-treated rats, mainly a decrease in the follicle area (colloid) and an increased epithelial height that resulted in an increased epithelial height/colloid ratio. Augmented collagen deposition was also seen in the thyroids of treated groups. In immunohistochemical (IHC) analyses, the localization of NIS protein was described and a significant increased proliferation index (evaluated by Ki67 positive cells) in the treated group was reported. As an indirect measurement of oxidative stress, mitochondrial protein SDHA was also analyzed by IHC analysis. Although the cytoplasmic expression of SDHA was observed in both groups, the staining intensity score was higher in TBT-treated group. Our results suggest that besides causing histomorphological changes, environmental relevant dose of TBT treatment can also induce oxidative alterations.

Mouse models of thyroid cancer: Bridging pathogenesis and novel therapeutics

Due to a global increase in the incidence of thyroid cancer, numerous novel mouse models were established to reveal thyroid cancer pathogenesis and test promising therapeutic strategies, necessitating a comprehensive review of translational medicine that covers (i) the role of mouse models in the research of thyroid cancer pathogenesis, and (ii) preclinical testing of potential anti-thyroid cancer therapeutics. The present review article aims to: (i) describe the current approaches for mouse modeling of thyroid cancer, (ii) provide insight into the biology and genetics of thyroid cancers, and (iii) offer guidance on the use of mouse models for testing potential therapeutics in preclinical settings. Based on research with mouse models of thyroid cancer pathogenesis involving the RTK, RAS/RAF/MEK/ERK, PI3K/AKT/mTOR, SRC, and JAK-STAT signaling pathways, inhibitors of VEGFR, MEK, mTOR, SRC, and STAT3 have been developed as anti-thyroid cancer drugs for "bench-to-bedside" translation. In the future, mouse models of thyroid cancer will be designed to be ''humanized" and "patient-like," offering opportunities to: (i) investigate the pathogenesis of thyroid cancer through target screening based on the CRISPR/Cas system, (ii) test drugs based on new mouse models, and (iii) explore the underlying mechanisms based on multi-omics.

mTOR in Human Diseases

The human body regenerates constantly in part under the control of signaling pathways that regulate cell growth [...].

A Nonpump Function of Sodium Iodide Symporter in Thyroid Cancer via Cross-talk with PTEN Signaling

The sodium iodide symporter (NIS) is a classical iodide pump typically localized within the cell plasma membrane in thyroid cells, where NIS expression is believed to ensure success of mainstay radioiodide therapy in thyroid cancers. Although radioiodide uptake is generally reduced in thyroid cancer tissue, intracellular nonmembranous NIS has been reported to increase, suggesting that NIS serves a pump-independent function. Thyroid cancer is one of the major component cancers of Cowden syndrome, a subset of which is caused by germline mutations in PTEN In this study, we explored the noncanonical tumorigenic role of NIS in thyroid cancer cells in relation to PTEN signaling. PTEN knockdown in thyroid cancer cell lines stabilized intracellular NIS protein by promoting an interaction with NIS-LARG (leukemia-associated RhoA guanine exchange factor). Increased protein levels of cytoplasmic NIS enhanced RhoA activation and resulted in a promigration tumorigenic phenotype. Inhibition of NIS glycosylation through activation of the PI3K/AKT/mTOR signaling pathway contributed to mislocalization of NIS in the cytoplasm, facilitating its nonpump tumorigenic function through an interaction with LARG, which predominantly localized in the cytoplasm. Moreover, PTEN or PI3K/AKT/mTOR signaling could affect DPAGT1, a glycosylating enzyme involved in the initial step of N-linked glycosylation, to inhibit glycosylation of NIS. In summary, our results elucidate a pump-independent, protumorigenic role for NIS in thyroid cancer via its cross-talk with PTEN signaling.Significance: A novel pump-independent protumorigenic role of nonmembranous NIS challenges the presumption that radioiodine treatment of thyroid cancer is ineffective when transmembrane NIS is not expressed. Cancer Res; 78(21); 6121-33. ©2018 AACR.