Signaling Pathways in Thyroid Cancer and Their Therapeutic Implications

Promising Therapeutic Targets for Recurrent/Metastatic Anaplastic Thyroid Cancer

OPINION STATEMENT

Anaplastic thyroid cancer presents formidable challenges, particularly in cases of recurrence or metastasis. Timely BRAF V600E testing is imperative at diagnosis, initially through immunohistochemistry, followed by comprehensive genomic profiling encompassing genes such as NTRK, RET, ALK, and assessment of tumor mutation burden (TMB). FDA-approved treatment options include dabrafenib and trametinib for patients with BRAF mutations, while those exhibiting high TMB may benefit from pembrolizumab. Further therapeutic decisions hinge upon mutational profile, urgency of response required, airway integrity, and access to targeted therapies There is growing use of immunotherapy for ATC based on published reports of activity, but currently there is no FDA approved agent for ATC. The off-label utilization of "precision medicine" combinations imposes a considerable financial strain, underscoring the necessity for further clinical trials to elucidate promising therapeutic avenues for this orphan disease. There is a pressing need for the development and support of clinical trials investigating genomically driven and immune-based therapies for anaplastic thyroid cancer.

Exosomal noncoding RNAs: decoding their role in thyroid cancer progression

Exosomes, as pivotal entities within the tumor microenvironment, orchestrate intercellular communication through the transfer of diverse molecules, among which non-coding RNAs (ncRNAs) such as miRNAs, lncRNAs, and circRNAs play a crucial role. These ncRNAs, endowed with regulatory functions, are selectively incorporated into exosomes. Emerging evidence underscores the significance of exosomal ncRNAs in modulating key oncogenic processes in thyroid cancer (TC), including proliferation, metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, and immunoediting. The unique composition of exosomes shields their cargo from enzymatic and chemical degradation, ensuring their integrity and facilitating their specific expression in plasma. This positions exosomal ncRNAs as promising candidates for novel diagnostic and prognostic biomarkers in TC. Moreover, the potential of exosomes in the therapeutic landscape of TC is increasingly recognized. This review aims to elucidate the intricate relationship between exosomal ncRNAs and TC, fostering a deeper comprehension of their mechanistic involvement. By doing so, it endeavors to propel forward the exploration of exosomal ncRNAs in TC, ultimately paving the way for innovative diagnostic and therapeutic strategies predicated on exosomes and their ncRNA content.

Mouse Models to Examine Differentiated Thyroid Cancer Pathogenesis: Recent Updates

Although the overall prognosis of differentiated thyroid cancer (DTC), the most common endocrine malignancy, is favorable, a subset of patients exhibits aggressive features. Therefore, preclinical models that can be utilized to investigate DTC pathogenesis and novel treatments are necessary. Various mouse models have been developed based on advances in thyroid cancer genetics. This review focuses on recent progress in mouse models that have been developed to elucidate the molecular pathogenesis of DTC.

Low-Density Lipoprotein Receptor Is a Key Driver of Aggressiveness in Thyroid Tumor Cells

We previously described the role of low-density lipoprotein (LDL) in aggressiveness in papillary thyroid cancer (PTC). Moreover, the MAPK signaling pathway in the presence of BRAF V600E mutation is associated with more aggressive PTC. Although the link between MAPK cascade and LDL receptor (LDLR) expression has been previously described, it is unknown whether LDL can potentiate the adverse effects of PTC through it. We aimed to investigate whether the presence of LDL might accelerate the oncogenic processes through MAPK pathway in presence or absence of BRAF V600E in two thyroid cell lines: TPC1 and BCPAP (wild-type and BRAF V600E, respectively). LDLR, PI3K-AKT and RAS/RAF/MAPK (MEK)/ERK were analyzed via Western blot; cell proliferation was measured via MTT assay, cell migration was studied through wound-healing assay and LDL uptake was analyzed by fluorometric and confocal analysis. TPC1 demonstrated a time-specific downregulation of the LDLR, while BCPAP resulted in a receptor deregulation after LDL exposition. LDL uptake was increased in BCPAP over-time, as well as cell proliferation (20% higher) in comparison to TPC1. Both cell lines differed in migration pattern with a wound closure of 83.5 ± 9.7% after LDL coculture in TPC1, while a loss in the adhesion capacity was detected in BCPAP. The siRNA knockdown of LDLR in LDL-treated BCPAP cells resulted in a p-ERK expression downregulation and cell proliferation modulation, demonstrating a link between LDLR and MAPK pathway. The modulation of BRAF-V600E using vemurafenib-impaired LDLR expression decreased cellular proliferation. Our results suggest that LDLR regulation is cell line-specific, regulating the RAS/RAF/MAPK (MEK)/ERK pathway in the LDL-signaling cascade and where BRAF V600E can play a critical role. In conclusion, targeting LDLR and this downstream signaling cascade, could be a new therapeutic strategy for PTC with more aggressive behavior, especially in those harboring BRAF V600E.

Dasatinib and Trametinib Promote Anti-Tumor Metabolic Activity

Thyroid cancer is the most common endocrine neoplasm, and despite its overall high survival rate, patients with metastatic disease or tumors that resist radioactive iodine experience a significantly worse prognosis. Helping these patients requires a better understanding of how therapeutics alter cellular function. Here, we describe the change in metabolite profiles after treating thyroid cancer cells with the kinase inhibitors dasatinib and trametinib. We reveal alterations to glycolysis, the TCA cycle, and amino acid levels. We also highlight how these drugs promote short-term accumulation of the tumor-suppressive metabolite 2-oxoglutarate, and demonstrate that it reduces the viability of thyroid cancer cells in vitro. These results show that kinase inhibition profoundly alters the metabolome of cancer cells and highlight the need to better understand how therapeutics reprogram metabolic processes, and ultimately, cancer cell behavior.

Role of the G Protein-Coupled Receptors in Cancer and Stromal Cells: From Functions to Novel Therapeutic Perspectives

G protein-coupled receptors (GPCRs) are transmembrane signal transducers that regulate a plethora of physiological and pathological processes [...].

Alantolactone Inhibits Melanoma Cell Culture Viability and Migration and Promotes Apoptosis by Inhibiting Wnt/β-Catenin Signaling

BACKGROUND

Melanoma is a highly invasive and metastatic malignant tumor originating from melanocytes and is associated with a poor prognosis. Surgical resection and chemotherapy are currently the main therapeutic options for malignant melanoma; however, their efficacy is poor, highlighting the need for the development of new, safe, and effective drugs for the treatment of this cancer.

OBJECTIVE

To investigate the effects of alantolactone (ALT) on the proliferative, migratory, invasive, and apoptotic ability of malignant melanoma cells and explore its potential anticancer mechanism.

METHODS

Melanoma cells (A375 and B16) were treated with different concentrations (4, 6, 8, and 10 μmol/L) of ALT, with DMSO and no treatment serving as controls. The effects of the different concentrations of the drug on cell proliferation were assessed by crystal violet staining and CCK-8 assay. The effects on cell migration and invasion were detected by wound healing and Transwell assays, respectively. Flow cytometry was used to evaluate the effects of the drug on apoptosis and the cell cycle. ALT target genes in melanoma were screened using network pharmacology. Western blotting was used to measure the expression levels of the proliferation-related protein PCNA; the apoptosisrelated proteins Bax, Bcl-2, and caspase-3; the invasion and metastasis-related proteins MMP-2, MMP-7, MMP-9, vimentin, E-cadherin, and N-cadherin; and the canonical Wnt signaling pathway-related proteins β-catenin, c-Myc, and p-GSK3β. In addition, an l model of melanoma was established by the subcutaneous injection of A375 melanoma cells into nude mice, following which the effects of ALT treatment on malignant melanoma were determined in vivo.

RESULTS

Compared with the controls, the proliferative, migratory, and invasive capacity of ALT-treated melanoma cells was significantly inhibited, whereas apoptosis was enhanced (P<0.01), showing effects that were exerted in a dose-dependent manner. The expression levels of the pro-apoptotic proteins Bax and caspase-3, as well as those of the interstitial marker E-cadherin, were upregulated in melanoma cells irrespective of the ALT concentration (P<0.05). In contrast, the expression levels of the anti-apoptotic protein Bcl-2, the proliferation-related protein PCNA, and the invasion and metastasis-related proteins MMP-2, MMP-7, MMP-9, N-cadherin, and vimentin were downregulated (P<0.05). The network pharmacology results indicated that GSK3β may be a key ALT target in melanoma. Meanwhile, western blotting assays showed that ALT treatment markedly suppressed the expression of β-catenin as well as that of its downstream effector c-Myc, and could also inhibit GSK3β phosphorylation.

CONCLUSION

ALT can effectively inhibit the culture viability, migration, and invasion of A375 and B16 melanoma cells while also promoting their apoptosis. ALT may exert its anti-melanoma effects by inhibiting the Wnt/β-catenin signaling pathway. Combined, our data indicate that ALT has the potential as an effective and safe therapeutic drug for the treatment of melanoma.

PI3K/AKT/mTOR pathway and its related molecules participate in PROK1 silence-induced anti-tumor effects on pancreatic cancer

The PI3K/AKT/mTOR (phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin) pathway can be initiated by PROK1 (prokineticin 1), but its effect and mechanism of action in pancreatic carcinoma (PC) are not fully understood. In this study, we elucidated the roles of PROK1 and its related molecules in PC in vivo. PANC-1 cells with PROK1 knockdown were injected into BALB/c nude mice. The growth and weight of the tumor were monitored and measured, which was followed by TUNEL (terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling), immunohistochemical staining, and hematoxylin and eosin staining. The key proteins related to proliferation, apoptosis, and the PI3K/AKT/mTOR pathway were determined by Western blotting. We also used public databases to identify the molecules related to PROK1. The reduction of PROK1 inhibited angiopoiesis and promoted apoptosis in vivo. PCNA-1, cyclin D1, and Bcl-2 decreased considerably, while Bax and cleaved caspase-3 increased significantly after PROK1 inhibition. The PI3K/AKT/mTOR signal inhibition was also closely associated with PROK1 knockdown. The possible related molecules of PROK1, such as von Willebrand factor, were screened and considered to be involved in the aberrant activation of PI3K/AKT. In conclusion, PROK1 knockdown significantly prevented tumor growth and promoted apoptosis of human PC cells in vivo, where the PI3K/AKT/mTOR pathway was probably inhibited. Therefore, PROK1, along with its related molecules, might be important targets for PC therapy.

Clinical importance of PLA2R1 and RASSF9 in thyroid cancer and their inhibitory roles on the Wnt/β-catenin pathway and thyroid cancer cell malignant behaviors

Thyroid cancer is a common malignant tumor with rising incidence worldwide. The purpose of this study was to explore key genes in thyroid cancer. The differentially expressed genes were analyzed according to GEO datasets. PLA2R1 and RASSF9 levels were confirmed by UALCAN and the Human Protein Atlas databases. The disease free survival and linear correlation were analyzed by GEPIA. ROC curve was generated according to The Cancer Genome Atlas (TCGA) database. The methylation level and immune infiltration were analyzed using GSCA platform. PLA2R1, RASSF9 and Wnt/β-catenin-related protein levels were detected by western blotting. Cell proliferation was assessed by 5-ethynyl-2'-deoxyuridine assay. Cell invasion and migration were evaluated by Transwell assay. There were 2 common differentially expressed genes (PLA2R1 and RASSF9) in thyroid cancer from GSE104005, GSE65144 and GSE53157 datasets. Decreased PLA2R1 and RASSF9 were associated with advanced stages and lower disease free survival. PLA2R1 and RASSF9 methylation levels were enhanced in thyroid cancer samples compared with normal samples. PLA2R1 methylation level was negatively correlated to its mRNA level. PLA2R1 and RASSF9 were related to immune infiltration in thyroid cancer. PLA2R1 and RASSF9 expression was associated with radioiodine resistance, and positively correlated to expression of iodide uptake-related factors. Multiple signaling pathways were involved in the action mechanisms of PLA2R1 and RASSF9, including the Wnt/β-catenin signaling. Overexpression of PLA2R1 and RASSF9 inhibited the activation of the Wnt/β-catenin pathway, proliferation, invasion, and migration in thyroid cancer cells. Collectively, PLA2R1 and RASSF9 are two key genes in thyroid cancer, which have potential diagnostic, prognostic, and anti-tumor effects in thyroid cancer.

Serum TSH Level as a Simple Efficient Tool to Assess the Risk of Thyroid Malignancy in Euthyroid Patients with Indeterminate Cytology - A Cohort Study

Context

A significant number of fine-needle aspiration cytology (FNAC) for thyroid nodules is reported as indeterminate. Expensive molecular testing can give a clue to the possibility of malignancy in this group. The effectiveness of serum thyroid-stimulating hormone (TSH) levels as a diagnostic tool in euthyroid patients with indeterminate cytology has not been previously studied, especially in the Indian population.

Aims

This study was conducted to evaluate the predictive efficacy of serum TSH in the early diagnosis and treatment of malignancy.

Settings and Design

This is a retrospective cross-sectional study on a cohort of patients who presented to our department with complaints of thyroid swelling and underwent thyroidectomy.

Methods and Material

Euthyroid patients who underwent thyroid surgery for newly diagnosed thyroid nodules with FNAC reported as indeterminate cytology were included in our study. Based on the histopathological report, the patients were divided into two groups and into quartiles based on TSH values.

Statistical Analysis Used

The mean difference in the numerical variables between groups was compared using the independent two-sample 't' test for parametric data and Mann-Whitney 'u' test for non-parametric data. A logistic regression analysis was done with age, sex, TSH level and nodule size as dependant variables and malignancy as the independent variable.

Results

There were 211 patients in group A and 93 in group B. Patients with malignancy confirmed on final histopathology showed higher serum TSH levels compared to benign nodules (2.93 ± 1.067 vs 1.73 ± 1.051, P = <0.001). The mean TSH levels of all types of malignant nodules correlated with our test model (>2.185 mIU/L).

Conclusions

Serum TSH above 2.185 mIU/mL is a good predictor of malignancy in indeterminate nodules. It is an inexpensive, safe and reliable diagnostic screening test for the risk of malignancy in an indeterminate nodule.

Emerging role of competing endogenous RNA and associated noncoding RNAs in thyroid cancer

Cancer of the thyroid is the most common endocrine malignancy. While treatment options are limited for individuals with medullary or anaplastic thyroid cancer, understanding the underlying mechanisms is vital to developing a successful thyroid cancer treatment strategy due to the tumor's multistep carcinogenesis. Non-coding RNAs (ncRNAs) have been associated with thyroid cancer progression in several recent studies; however, the role of regulatory interactions among different types of ncRNAs in thyroid cancer remains unclear. Recently, competing endogenous RNA (ceRNA) has been discovered as a mechanism demonstrating regulatory interactions among non-coding RNAs, including pseudogenes, long non-coding RNAs (lnRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs). It has been concluded from the literature that numerous ceRNA networks are deregulated during the development, invasion, and metastasis of thyroid cancer, as well as in epithelial-mesenchymal transition (EMT) and drug resistance. Further understanding of these deregulations is important to develop diagnostic procedures for early detection of thyroid cancer and promising therapeutic options for effective treatment. The purpose of this review is to highlight the emerging roles of some newly found ceRNA members in thyroid cancer and outline the current body of knowledge regarding ceRNA, lncRNA, pseudogenes, and miRNAs.

Monensin inhibits anaplastic thyroid cancer via disrupting mitochondrial respiration and AMPK/mTOR signaling

OBJECTIVE

The clinical management of anaplastic thyroid cancer (ATC) remains challenging and novel treatment methods are needed. Monensin is a carboxyl polyether ionophore that potently inhibits the growth of various cancer types. Our current work investigates whether monensin has selective anti-ATC activity and systematically explores its underlying mechanisms.

METHODS

Proliferation and apoptosis assays were performed using a panel of thyroid cancer cell lines. Mitochondrial biogenesis profiles, ATP levels, oxidative stress, AMPK and mTOR were examined in these cells after monensin treatment.

RESULTS

Monensin is effective to inhibit proliferation and induce apoptosis in a number of thyroid cancer cell lines. The results are consistent across cell lines of varying cellular origins and genetic mutations. Compared to other thyroid cancer cell types, ATC cell lines are the most sensitive to monensin. Of note, monensin used at our experimental concentration affects less of normal cells. Mechanistic studies reveal that monensin acts on ATC cells through disrupting mitochondrial function, inducing oxidative stress and damage, and AMPK activation-induced mTOR inhibition. We further show mitochondrial respiration is a critical target for monensin in ATC cells.

CONCLUSIONS

Our pre-clinical findings demonstrate the selective anti-ATC activities of monensin. This is supported by increasing evidence monensin can to be repurposed as a potential anti-cancer drug.

Di(2-ethylhexyl) phthalate (DEHP) and thyroid: biological mechanisms of interference and possible clinical implications

Di(2-ethylhexyl) phthalate (DEHP) is a ubiquitous environmental endocrine disruptor. DEHP can be absorbed into the human body through the air, food, water, and skin. After entering the human body, DEHP is rapidly converted to mono(2-ethylhexyl) phthalate (MEHP) with greater toxicity than DEHP. An increasing number of studies indicates that DEHP or MEHP can damage the thyroid tissue and disrupt the function, but the mechanisms remain unclear. This article reviews the toxicity of DEHP on thyroid structures and functions and summarizes the potential mechanisms to provide evidence for preventing the thyroid-related diseases.

Epigenetic modification and BRAF gene mutation in thyroid carcinoma

Thyroid cancer remains the most prevailing endocrine malignancy, and a progressively increasing incidence rate has been observed in recent years, with 95% of thyroid cancer represented by differentiated thyroid carcinomas. The genetics and epigenetics of thyroid cancer are gradually increasing, and gene mutations and methylation changes play an important roles in its occurrence and development. Although the role of RAS and BRAF mutations in thyroid cancer have been partially clarified,but the pathogenesis and molecular mechanisms of thyroid cancer remain to be elucidated. Epigenetic modification refer to genetic modification that does not change the DNA sequence of a gene but causes heritable phenotypic changes in its expression. Epigenetic modification mainly includes four aspects: DNA methylation, chromatin remodelling, noncoding RNA regulation, and histone modification. This article reviews the importance of thyroid cancer epigenetic modification and BRAF gene mutation in the treatment of thyroid cancer.

Novel Inhibitor-Based Therapies for Thyroid Cancer-An Update

Thyroid cancers (TCs) are the most common tumors of the endocrine system and a constant rise in the number of TC cases has been observed for the past few decades. TCs are one of the most frequent tumors in younger adults, especially in women, therefore early diagnosis and effective therapy are especially important. Ultrasonography examination followed by fine needle biopsy have become the gold standard for diagnosis of TCs, as these strategies allow for early-stage detection and aid accurate qualification for further procedures, including surgical treatment. Despite all the advancements in detection and treatment of TCs, constant mortality levels are still observed. Therefore, a novel generation line of targeted treatment strategies is being developed, including personalized therapies with kinase inhibitors. Recent molecular studies on TCs demonstrate that kinase inhibitor-based therapies might be considered as the most promising. In the past decade, new kinase inhibitors with different mechanisms of action have been reported and approved for clinical trials. This review presents an up-to-date picture of new approaches and challenges of inhibitor-based therapies in treatment of TCs, focusing on the latest findings reported over the past two years.

Synergistic effect of metformin and vemurufenib (PLX4032) as a molecular targeted therapy in anaplastic thyroid cancer: an in vitro study

BACKGROUND

Survival rate of patients affected with anaplastic thyroid carcinoma (ATC) is less than 5% with current treatment. In ATC, BRAF^V600E mutation is the major mutation that results in the transformation of normal cells in to an undifferentiated cancer cells via aberrant molecular signaling mechanisms. Although vemurufenib is a selective oral drug for the BRAF^V600E mutant kinase with a response rate of nearly 50% in metastatic melanoma, our study has showed resistance to this drug in ATC. Hence the rationale of the study is to explore combinational therapeutic effect to improve the efficacy of vemurafenib along with metformin. Metformin, a diabetic drug is an AMPK activator and has recently proved to be involved in preventing or treating several types of cancer.

METHODS AND RESULTS

Using iGEMDock software, a protein-ligand interaction was successful between Metformin and TSHR (receptor present in the thyroid follicular cells). Our study demonstrates that combination of vemurufenib with metformin has synergistic anti-cancer effects which was evaluated through MTT assay (cytotoxicity), colony formation assay (antiproliferation evaluation) and suppressed the progression of ATC cells growth by inducing significant apoptosis, proven by Annexin V-FITC assay (Early Apoptosis Detection). Downregulation of ERK signaling, upregulation of AMPK pathway and precision in epithelial-mesenchymal transition (EMT) pathway which were assessed by RT-PCR and Western blot provide the evidence that the combination of drugs involved in the precision of altered molecular signaling Further our results suggest that Metformin act as a demethylating agent in anaplastic thyroid cancer cells by inducing the expression of NIS and TSHR. Our study for the first time explored cAMP signaling in ATC wherein cAMP signaling is downregulated due to decrease in intracellular cAMP level upon metformin treatment.

CONCLUSION

To conclude, our findings demonstrate novel therapeutic targets and treatment strategies for undifferentiated ATC.

CircRNA NRIP1 promotes papillary thyroid carcinoma progression by sponging mir-195-5p and modulating the P38 MAPK and JAK/STAT pathways

BACKGROUND

Circular RNAs (circRNAs) have become a hot topic in the area of tumor biology due to its closed structure and the post-transcriptional regulatory effect. This study aims to clarify the roles of circRNA nuclear receptor-interacting protein 1 (NRIP1; circNRIP1) and the possible mechanisms in papillary thyroid carcinoma (PTC).

METHODS

The real-time PCR was used to detect the expression level of CircRNA NRIP1 in PTC specimens and cell lines. The effects of CircRNA NRIP1 and miR-195-5p on the PTC cell functions were detected by MTT, transwell, and flow cytometry assays. Dual-luciferase reporter assays and pull down assays were used to verify the association between circRNA NRIP1 and miR-195-5p. The murine xenograft models were constructed to detect the roles of CircRNA NRIP1 and miR-195-5p. Western blot was applied to detect the effects of CircRNA NRIP1 and miR-195-5p on the P38 MAPK and JAK/STAT singling pathways.

RESULTS

CircRNA NRIP1 was over-expressed in PTC tissues and cells and the high levels of CircRNA NRIP1 were correlated with advanced PTC stage. Depletion of CircRNA NRIP1 inhibited PTC cell proliferation, invasion, while accelerated apoptosis. miR-195-5p upregulation repressed proliferation and invasion capabilities, and accelerated apoptosis of PTC cell lines and restraining the growth of tumor xenografts, while the functions were reversed following CircRNA NRIP1 overexpression in PTC cells and tumor xenografts. Besides, the protein levels of p-p38, p-JAK2 and p-STAT1 were remarkably down-regulated in miR-195-5p overexpressed PTC cells and tumor xenografts, whereas CircRNA NRIP1 up-regulation overturned the impacts.

CONCLUSIONS

In conclusion, CircRNA NRIP1 promoted PTC progression by accelerating PTC cells proliferation, invasion and tumor growth, while impeding apoptosis by way of sponging miR-195-5p and regulating the P38 MAPK and JAK/STAT pathways.

Intratumoral Heterogeneity in Differentiated Thyroid Tumors: An Intriguing Reappraisal in the Era of Personalized Medicine

Differentiated thyroid tumors (DTTs) are characterized by significant molecular variability in both spatial and temporal intra-tumoral heterogeneity (ITH), that could influence the therapeutic management. ITH phenomenon appears to have a relevant role in tumor growth, aggressive behavior and drug resistance. Accordingly, characteristics and consequences of ITH in DTTs should be better analyzed and understood in order to guide clinical practice, improving survival. Consequently, in the present review, we investigated morphological and molecular ITH of DTTs in benign, borderline neoplasms and in malignant entities, summarizing the most significant data. Molecular testing in DTTs documents a high risk for recurrence of cancer associated with BRAF^V600E, RET/PTC 1/3, ALK and NTRK fusions, while the intermediate risk may be related to BRAF^K601E, H/K/N RAS and PAX8/PPARγ. In addition, it may be suggested that tumor genotype is associated with peculiar phenotype.

Testicular orphan receptor 4 (TR4) promotes papillary thyroid cancer invasion via activating circ-FNLA/miR-149-5p/MMP9 signaling

The incidence and mortality of papillary thyroid cancer (PTC) have steadily increased. Although conventional therapies are very effective toward differentiated PTC patients, very limited therapeutic options are applicable to those patients with distant metastases. Therefore, better understanding of the molecular biology of metastatic PTC helps identify novel targets and facilitates the development of new therapies. In this study, we first found that testicular orphan receptor 4 (TR4) was significantly increased in PTC tumors spreading to lymph nodes compared to the paired primary tumors. Experimental evidence suggested that TR4 drove PTC progression via promoting its cell invasion and cell migration. Mechanistically, TR4 transcriptionally regulated the expression level of circ-filamin A (FLNA), which competed with matrix metalloproteinase 9 (MMP9) for microRNA (miR)-149-5p binding and led to an increased protein level of MMP9. Interruption assays with various gene manipulations verified that the TR4/circ-FLNA/miR-149-5p/MMP9 signaling axis played a central role in cell invasion and cell migration of PTC cells. Moreover, a xenografted mouse model also confirmed that the TR4/circ-FLNA signal promoted PTC tumor growth. Overall, our study pinpoints the oncogenic role of TR4 in PTC development, and the targeting of TR4/circ-FLNA/miR-149-5p/MMP9 signaling may be an alternative option for metastatic PTC patients.

Long non-coding RNA LIFR-AS1 regulates the proliferation, migration and invasion of human thyroid cancer cells

The long non-coding RNA (lncRNA) LIFR-AS1 has been shown to be involved in the development of several human cancers. This study was designed to determine the expression profile and role of lncRNA-LIFR-AS1 in human thyroid cancer. The results showed significant (p < 0.05) upregulation of LncRNA-LIFR-AS1 in thyroid cancer tissues and cells. However, silencing of LncRNA-LIFR-AS1 inhibited the viability and proliferation of human thyroid cancer cells inducing G2/M cell cycle arrest. The G2/M phase cells increased from 8.56% in negative control (NC) to around 35.03% in si-LIFR-AS1. This was also found to be concomitant with the downregulation of cyclin B1 and CDK1 expressions. The thyroid cancer cells exhibited remarkably lower invasion and migration under transcriptional knockdown of lncRNA-LIFR-AS1 which was also associated with downregulation of MMP-2 and MMP-9 expression. Importantly, transcriptional silencing of lncRNA-LIFR-AS1 inhibited thyroid cancer tumorigenesis, in vivo. Collectively, the results suggest the tumor-promoting role of lncRNA-LIFR-AS1 in thyroid cancer and highlight its potential as therapeutic target.

LncRNA ABCC6P1 promotes proliferation and migration of papillary thyroid cancer cells via Wnt/β-catenin signaling pathway

Background

LncRNAs play an important regulatory function in the occurrence and progression of papillary thyroid cancer (PTC). This study aimed to investigate the role and mechanism of ATP binding cassette subfamily C member 6 pseudogene 1 (ABCC6P1) in PTC.

Methods

Cancerous and paracancer normal thyroid tissues were collected from 18 patients with PTC, who were operated at the Second Affiliated Hospital of Harbin Medical University. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to investigate the levels of ABCC6P1. Cell proliferation was evaluated using Cell Counting Kit-8 (CCK-8) and colony formation assays. Wound healing and Transwell invasion assays were performed to examine cell migratory and invasive ability. Western blotting analysis was used to detect the expression levels of EMT-related markers and Wnt/β-catenin signaling pathway-related proteins.

Results

The expression of ABCC6P1 was upregulated in PTC tissues and cells. ABCC6P1 silencing could significantly suppress the proliferation, colony formation ability, migratory and invasive ability in PTC cells. Moreover, knockdown of ABCC6P1 induced cell cycle arrest at G0/G1 phase and inhibited epithelial-mesenchymal transition (EMT) process of PTC cells by increasing the E-cadherin expression, but downregulating N-cadherin and vimentin expression. In addition, knockdown of ABCC6P1 caused a significant decrease in levels of Wnt/β-catenin signaling pathway members (including β-catenin, c-myc, and cyclin D1) in PTC cells.

Conclusions

Our study confirms that ABCC6P1 exerts an oncogenic activity in PTC which may be mediated by the Wnt/β-catenin pathway, suggesting that ABCC6P1 may be a promising therapeutic target for PTC.

Cancer-associated fibroblasts (CAFs) in thyroid papillary carcinoma: molecular networks and interactions

In 1989, Stephen Paget proposed the 'seed and soil' theory of cancer metastasis. This theory has led to previous researchers focusing on the role of a tumour as a cancer seed and antiangiogenesis agents as cancer soil fumigant; for the latter to be effective, it is important for them to be able to distinguish cancer cells from stromal cells. However, antiangiogenesis agents have not produced dramatic survival benefits in vivo. This may be related to their inability to destroy the supporting stroma that promote cancer cell growth. Therefore, in order to effectively arrest cancer cell growth for therapeutic purposes, a paradigm shift is required in our fundamental approach to decipher the molecular events and networks in the stromal environment that cancer cells can thrive and proliferate. The pathogenesis of cancer is a multidimensional process of pathological molecular and cellular pathways, influencing different stromal properties and achieving a mutually negotiated crosstalk between cancer cells and stromal cells. This review summarises the clinical presentation of current knowledge of classical papillary thyroid carcinoma (PTC), emerging molecular diagnostics and future directions of classical PTC research.

Phosphoproteomics to Characterize Host Response During H3N2 Canine Influenza Virus Infection of Dog Lung

Avian-origin H3N2 canine influenza viruses (CIVs) cause severe contagious respiratory disease in dogs, and quickly adapt to new environments. To further understand the mechanism of virus infection and host-virus interactions, we characterized the complete phosphoproteome of dogs infected with H3N2 CIV. Nine-week-old Beagle dogs were inoculated intranasally with 10⁶ EID₅₀ of A/canine/Guangdong/04/2014 (H3N2) virus. Lung sections were harvested at 5 days post-inoculation (dpi) and processed for global and quantitative analysis of differentially expressed phosphoproteins. A total of 1,235 differentially expressed phosphorylated proteins were identified in the dog lung after H3N2 CIV infection, and 3,016 modification sites were identified among all differentially expressed proteins. We then performed an enrichment analysis of functional annotations using Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) database analyses to predict the functions of the identified differential phosphoproteins. Our data indicate that H3N2 CIV infection causes dramatic changes in the host protein phosphorylation of dog lungs. To our knowledge, this is the first study to assess the effect of H3N2 CIV infection on the phosphoproteome of beagles. These data provide novel insights into H3N2-CIV-triggered regulatory phosphorylation circuits and signaling networks and may improve our understanding of the mechanisms underlying CIV pathogenesis in dogs.

Non-Coding RNAs: Uncharted Mediators of Thyroid Cancer Pathogenesis

Thyroid cancer is the most prevalent malignancy of the endocrine system and the ninth most common cancer globally. Despite the advances in the management of thyroid cancer, there are critical issues with the diagnosis and treatment of thyroid cancer that result in the poor overall survival of undifferentiated and metastatic thyroid cancer patients. Recent studies have revealed the role of different non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) that are dysregulated during thyroid cancer development or the acquisition of resistance to therapeutics, and may play key roles in treatment failure and poor prognosis of the thyroid cancer patients. Here, we systematically review the emerging roles and molecular mechanisms of ncRNAs that regulate thyroid tumorigenesis and drug response. We then propose the potential clinical implications of ncRNAs as novel diagnostic and prognostic biomarkers for thyroid cancer.

Thyroid Cancer and Circadian Clock Disruption

Simple Summary

In this manuscript we review the recent literature supporting a biological link between circadian clock disruption and thyroid cancer development and progression. After a brief description of the involvement of the circadian clock machinery in the cell cycle, stemness and cancer, we discuss the scientific evidence supporting the contribution of circadian clockwork dysfunction in thyroid tumorigenesis and the possible molecular mechanisms underlying this relationship. We also point out the potential clinical implications of this link highlighting its impact on thyroid cancer prevention, diagnosis and therapy.

Abstract

Thyroid cancer (TC) represents the most common malignancy of the endocrine system, with an increased incidence across continents attributable to both improvement of diagnostic procedures and environmental factors. Among the modifiable risk factors, insulin resistance might influence the development of TC. A relationship between circadian clock machinery disfunction and TC has recently been proposed. The circadian clock machinery comprises a set of rhythmically expressed genes responsible for circadian rhythms. Perturbation of this system contributes to the development of pathological states such as cancer. Several clock genes have been found deregulated upon thyroid nodule malignant transformation. The molecular mechanisms linking circadian clock disruption and TC are still unknown but could include insulin resistance. Circadian misalignment occurring during shift work, jet lag, high fat food intake, is associated with increased insulin resistance. This metabolic alteration, in turn, is associated with a well-known risk factor for TC i.e., hyperthyrotropinemia, which could also be induced by sleep disturbances. In this review, we describe the mechanisms controlling the circadian clock function and its involvement in the cell cycle, stemness and cancer. Moreover, we discuss the evidence supporting the link between circadian clockwork disruption and TC development/progression, highlighting its potential implications for TC prevention, diagnosis and therapy.

Notch Signaling in Thyroid Cancer

Thyroid cancer is the most common malignancy of the endocrine system with a steadily rising incidence. The term "thyroid cancer" encompasses a spectrum of subtypes, namely papillary thyroid cancer, follicular thyroid cancer, anaplastic thyroid cancer, and medullary thyroid cancer. Each subtype differs histopathologically and in degrees of cellular differentiation, which may be in part due to signaling of the Notch pathway. The Notch pathway is an evolutionarily conserved signal transduction mechanism that regulates cell proliferation, differentiation, survival, stem cell maintenance, embryonic and adult development, epithelial-mesenchymal transition, and angiogenesis. Its role in cancer biology is controversial, as it has been shown to play both an oncogenic and tumor-suppressive role in many different types of cancers. This discordance holds true for each subtype of thyroid cancer, indicating that Notch signaling is likely cell type and context dependent. Whether oncogenic or not, Notch signaling has proven to be significantly involved in the tumorigenesis of thyroid cancer and has thus earned interest as a therapeutic target. Advancement in the understanding of Notch signaling in thyroid cancer holds great promise for the development of novel treatment strategies to benefit patients.

MiR-3121-3p promotes tumor invasion and metastasis by suppressing Rap1GAP in papillary thyroid cancer in vitro

Background

Rap1GAP is a tumor suppressor and is downregulated in human malignancies including papillary thyroid cancer (PTC). The mechanism of its suppression in PTC remains unclear.

Methods

Bioinformatic analyses were carried out to evaluate clinical significance and to predict upstream miRNA bindings of Rap1GAP. Three PTC cell lines, TPC-1, B-CPAP, and K1, were employed for functional verification and further experiments. We used dual-luciferase reporter gene assay to confirm the miRNA binding prediction, Western blotting and quantitative polymerase chain reaction (qPCR) to explore miRNA and Rap1GAP regulation, Transwell and wound healing assays to compare cell migration and invasion after protein knockout or overexpression, and Cell Counting Kit-8 (CCK-8) assay to evaluate cell proliferation.

Results

Rap1GAP expression was suppressed in thyroid cancer compared to adjacent normal tissues and was a potential diagnostic marker of PTC. Rap1GAP suppression was correlated to younger age, advanced T stage, N stage, extrathyroidal extension, BRAF-like tumors, and higher risk of recurrence. Combined analysis of bioinformatic prediction and dual-luciferase assay revealed binding between miR-3121-3p with 3'UTR of Rap1GAP promoter. MiR-3121-3p promoted cell migration, invasion, and proliferation via inhibiting Rap1GAP and thus upregulating MAPK pathway. Overexpression and knockdown of Rap1GAP could counteract the influence on cell migration and invasion carried out by miR-3121-3p mimic and inhibitor, respectively. Rap1GAP partially impaired the effect of miR-3121-3p in cell growth in the CCK-8 assay.

Conclusions

Rap1GAP expression is suppressed in PTC and is a potential diagnostic marker. Its upstream regulator, miR-3121-3p, affects tumor metastasis and proliferation via regulating Rap1GAP expression. MAPK signaling pathway may be involved in this effect.

Exosomal miRNAs are potential diagnostic biomarkers between malignant and benign thyroid nodules based on next-generation sequencing

An accurate biomarker or method for diagnosis of thyroid nodule with indeterminate fine-needle aspiration result is essential for clinical treatment. Micro RNAs (miRNAs) of exosomes are advantageous in the diagnosis of tumors because they are highly stable, and be protected by a bilayer membrane structure. Exosomes were isolated from 13 papillary thyroid carcinoma (PTC) and 7 nodular goiter (NG) patients' plasma. Small RNA sequencing was performed on exosomes' RNA in next-generation sequencing (NGS) platform. Then, we performed comprehensive analysis on miRNA expression profile in exosome of two groups. One hundred and twenty-nine differentially expressed miRNAs were identified in plasma exosomes between PTC and NG patients. Forty-nine miRNAs were up-regulated, and 80 miRNAs were down-regulated in PTC patients. Receiver operating characteristic (ROC) curves of 129 miRNAs were plotted. Area under curve (AUC) of 129 miRNAs was 0.571-0.951, with distribution peak of 0.82-0.86. AUC of 11 miRNAs was above 0.9, miR-5189-3p had the most optimal performance for diagnosis between PTC and NG, with 0.951 of AUC. Target genes of 129 miRNAs were enriched into 7 cancer-related signaling pathways, including mitogen-activated protein kinase (MAPK), tumor necrosis factor (TNF), NF-kappa B signaling pathway and so on. This study profiled the miRNA signature of exosomes from PTC patients and NG patients. We proposed a group of miRNAs in plasma exosomes as candidate biomarkers for thyroid nodule diagnosis.

The Changing Face of in vitro Culture Models for Thyroid Cancer Research: A Systematic Literature Review

Background: Thyroid cancer is the most common endocrine malignancy worldwide. Primary treatment with surgery and radioactive iodine is usually successful, however, there remains a small proportion of thyroid cancers that are resistant to these treatments, and often represent aggressive forms of the disease. Since the 1950s, in vitro thyroid culture systems have been used in thyroid cancer research. In vitro culture models have evolved from 2-dimensional thyrocyte monolayers into physiologically functional 3-dimensional organoids. Recently, research groups have utilized in vitro thyroid cancer models to identify numerous genetic and epigenetic factors that are involved with tumorigenesis as well as test the efficacy of cytotoxic drugs on thyroid cancer cells and identify cancer stem cells within thyroid tumors.

Objective of Review: The objective of this literature review is to summarize how thyroid in vitro culture models have evolved and highlight how in vitro models have been fundamental to thyroid cancer research.

Type of Review: Systematic literature review.

Search Strategy: The National Institute for Health and Care Excellence (NICE) Healthcare and Databases Advanced Search (HDAS) tool was used to search EMBASE, Medline and PubMed databases. The following terms were included in the search: “in vitro” AND “thyroid cancer”. The search period was confined from January 2008 until June 2019. A manual search of the references of review articles and other key articles was also performed using Google Scholar.

Evaluation Method: All experimental studies and review articles that explicitly mentioned the use of in vitro models for thyroid cancer research in the title and/or abstract were considered. Full-text versions of all selected articles were evaluated. Experimental studies were reviewed and grouped according to topic: genetics/epigenetics, drug testing/cancer treatment, and side populations (SP)/tumor microenvironment (TME).

Results: Three thousand three hundred and seventy three articles were identified through database and manual searches. One thousand two hundred and sixteen articles remained after duplicates were removed. Five hundred and eighty nine articles were excluded based on title and/or abstract. Of the remaining 627 full-text articles: 24 were review articles, 332 related to genetic/epigenetics, 240 related to drug testing/treatments, and 31 related to SP/TME.

Conclusion:In vitro cell culture models have been fundamental in thyroid cancer research. There have been many advances in culture techniques- developing complex cellular architecture that more closely resemble tumors in vivo. Genetic and epigenetic factors that have been identified using in vitro culture models can be used as targets for novel drug therapies. In the future, in vitro systems will facilitate personalized medicine, offering bespoke treatments to patients.

Regulators of glucose uptake in thyroid cancer cell lines

Abstract

Thyroid cancer is the most common sort of endocrine-related cancer with more prevalent in women and elderly individuals which has quickly widespread expansion in worldwide over the recent decades. Common features of malignant thyroid cells are to have accelerated metabolism and increased glucose uptake to optimize their energy supply which provides a fundamental advantage for growth. In tumor cells the retaining of required energy charge for cell survival is imperative, indeed glucose transporters are enable of promoting of this task. According to this relation it has been reported the upregulation of glucose transporters in various types of cancers. Human studies indicated that poor survival can be occurred following the high levels of GLUT1 expression in tumors. GLUT-1 and GLUT3 are the glucose transporters which seems to be mainly engaged with the oncogenesis of thyroid cancer and their expression in malignant tissues is much more than in the normal one. They are promising targets for the advancement of anticancer strategies. The lack of oncosuppressors have dominant effect on the membrane expression of GLUT1 and glucose uptake. Overexpression of hypoxia inducible factors have been additionally connected with distant metastasis in thyroid cancers which mediates transcriptional regulation of glycolytic genes including GLUT1 and GLUT3. Though the physiological role of the thyroid gland is well illustrated, but the metabolic regulations in thyroid cancer remain evasive. In this study we discuss proliferation pathways of the key regulators and signaling molecules such as PI3K-Akt, HIF-1, MicroRNA, PTEN, AMPK, BRAF, c-Myc, TSH, Iodide and p53 which includes in the regulation of GLUTs in thyroid cancer cells. Incidence of deregulations in cellular energetics and metabolism are the most serious signs of cancers. In conclusion, understanding the mechanisms of glucose transportation in normal and pathologic thyroid tissues is critically important and could provide significant insights in science of diagnosis and treatment of thyroid disease.

Impact of the Tumor Microenvironment on the Gene Expression Profile in Papillary Thyroid Cancer

Transcriptome of papillary thyroid cancer (PTC) is well characterized and correlates with some prognostic and genotypic factors, but data addressing the interaction between PTC and tumor microenvironment (TME) are scarce. Therefore, in the present study, we aimed to assess the impact of TME on gene expression profile in PTC. We evaluated the gene expression profile in PTC and normal thyroid cells isolated by laser capture microdissection and in whole tissue slides corresponding to the entire tumor. We included 26 microdissected samples for gene expression analysis (HG-U133 PLUS 2.0, Affymetrix, currently Thermo Fisher Scientific USA): 15 PTC samples, 11 samples of normal thyrocytes, and 30 whole slides (15 PTC and 15 normal thyroid). Transcripts were divided into three groups: differentially expressed both in microdissected and whole slides, transcripts differently expressed in microdissected samples and not changed in whole slides, and transcripts differentially expressed in whole slides and not changed in microdissected samples. Eleven genes were selected for validation in an independent set of samples; among them, four genes differentiated only microdissected PTC and normal cells. Two genes (PTCSC and CTGF) were confirmed. One gene (FOS) was not confirmed by the validation, whereas EGR1 was also significant in whole slide analysis. The other seven genes (TFF3, FN1, MPPED2, MET, KCNJ2, TACSTD2, and GALE) showed differentiated expression in microdissected thyrocytes and in whole tumor slides. Most of identified genes were related to the tumor-microenvironment interaction and confirmed the crosstalk between TME and cancer cells.

Linkage disequilibrium and haplotype analysis of Src and Yes1 genes in thyroid cancer

Purpose: This study was planned to examine the effects of Src and Yes1 single nucleotide polymorphism (SNPs) on the risk of thyroid cancer in 499 patients and 500 controls. Materials & methods: Three SNPs of Src gene and three SNPs of Yes1 gene were analyzed using Tetra-primer ARMS-PCR followed by sequencing. Results: rs121913314 of Src gene genotype TT showed 32-fold increased risk of thyroid cancer and rs2305994 of Yes1 genotypes TT and CT showed 2.7-fold and 16-fold increased risk in thyroid cancer (p < 0.0001). Haplotype analysis revealed that CATGCC, CATGCT, CATGTC, CATGTT, TATGCC and TATGTTA haplotypes are associated with thyroid cancer risk. Conclusion: Results showed that genotypes and allele distribution of Src and Yes1 genes are significantly linked with increased risk of thyroid cancer.

Combinatorial Therapies in Thyroid Cancer: An Overview of Preclinical and Clinical Progresses

Accounting for about 2% of cancers diagnosed worldwide, thyroid cancer has caused about 41,000 deaths in 2018. Despite significant progresses made in recent decades in the treatment of thyroid cancer, many resistances to current monotherapies are observed. In our complete review, we report all treatments that were tested in combination against thyroid cancer. Many preclinical studies investigating the effects of inhibitors of the MAPK and PI3K pathways highlighted the importance of mutations in such signaling pathways and their impacts on the subsequent efficacy of targeted therapies, thus reinforcing the need of more personalized therapeutic strategies. Our review also points out the multiple possibilities of combinatory strategies, particularly using therapies targeting proliferation, survival, angiogenesis, and in combination with conventional treatments such as chemotherapies. In any case, resistances to anticancer therapies always develop through the activation of alternative signaling pathways. Combinatory treatments aim to blockade such mechanisms, which are gradually decrypted, thus offering new perspectives for the future. The preclinical and clinical aspects of our review allow us to have a global opinion of the different therapeutic options currently evaluated in combination and to be aware about new perspectives of treatment of thyroid cancer.

Propofol upregulates miR-320a and reduces HMGB1 by downregulating ANRIL to inhibit PTC cell malignant behaviors

BACKGROUND

Our previous study states that propofol suppresses proliferation and migration of papillary thyroid cancer (PTC) cells by downregulation of lncRNA ANRIL. This study intended to probe the downstream mechanism of ANRIL in PTC with potential microRNAs (miR) and genes.

METHODS

ANRIL expression was detected in normal thyroid epithelial cells (Nthy-ori 3-1) and PTC cells (TPC-1, FTC-133, K1 and BCPAP). ANRIL expression was inhibited in TPC-1 and BCPAP cells to explore the effects of si-ANRIL in PTC malignant behaviors. The gain-and loss-of functions of ANRIL/miR-320a were performed to measure their roles in PTC. Levels of ANRIL, miR-320a, HMGB1, apoptosis- and Wnt/β-catenin and NF-κB pathways-related proteins were measured. Dual-luciferase reporter gene assay and RNA pull-down assay were applied to verify ANRIL/miR-320a/HMGB1 relation. si-ANRIL was transplanted into xenograft tumors in nude mice.

RESULTS

ANRIL was upregulated in TPC-1 and BCPAP cells. miR-320a targeted HMGB1, and ANRIL bound to miR-320a. In TPC-1 and BCPAP cells, si-ANRIL prevented PTC cell malignant behaviors, and inactivated the Wnt/β-catenin and NF-κB pathways; while si-ANRIL + miR-320a inhibition showed opposite trends. Overexpressing miR-320a promoted malignant behaviors of TPC-1 cells. In 6 μg/mL propofol-treated TPC-1 cells, miR-320a inhibition weakened propofol's inhibitory effects on PTC cell growth. After ANRIL inhibition, the volume and weight of xenograft tumors were decreased.

CONCLUSION

Propofol upregulated miR-320a and reduced HMGB1 by downregulating ANRIL and inactivating the Wnt/β-catenin and NF-κB pathways, thus preventing PTC cell malignant behaviors. This study may offer new insights in PTC prevention and treatment.

Curcumin-Mediated Apoptotic Cell Death in Papillary Thyroid Cancer and Cancer Stem-Like Cells through Targeting of the JAK/STAT3 Signaling Pathway

The constitutive activation of Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) signal transduction is well elucidated in STAT3-mediated oncogenesis related to thyroid cancer and is considered to be a plausible therapeutic target. Hence, we investigated whether curcumin, a natural compound, can target the JAK/STAT3 signaling pathway to induce cytotoxic effects in papillary thyroid cancer (PTC) cell lines (BCPAP and TPC-1) and derived thyroid cancer stem-like cells (thyrospheres). Curcumin suppressed PTC cell survival in a dose-dependent manner via the induction of caspase-mediated apoptosis and caused the attenuation of constitutively active STAT3 (the dephosphorylation of Tyr705-STAT3) without affecting STAT3. Gene silencing with STAT3-specific siRNA showed the modulation of genes associated with cell growth and proliferation. The cotreatment of PTC cell lines with curcumin and cisplatin synergistically potentiated cytotoxic effects via the suppression of JAK/STAT3 activity along with the inhibition of antiapoptotic genes and the induction of proapoptotic genes, and it also suppressed the migration of PTC cells by downregulating matrix metalloproteinases and the inhibition of colony formation. Finally, thyrospheres treated with curcumin and cisplatin showed suppressed STAT3 phosphorylation, a reduced formation of thyrospheres, and the downregulated expression of stemness markers, in addition to apoptosis. The current study's findings suggest that curcumin synergistically enhances the anticancer activity of cisplatin in PTC cells as well as in cancer stem-like cells by targeting STAT3, which suggests that curcumin combined with chemotherapeutic agents may provide better therapeutic outcomes.

Genetic alterations in anaplastic thyroid carcinoma and targeted therapies

Thyroid cancer is the most common type of endocrine malignancy, and its incidence is increasing. Anaplastic thyroid cancer (ATC), referring to undifferentiated subtypes, is considered to be aggressive and associated with poor prognosis. Conventional therapies, including surgery, chemotherapy and radioiodine therapy, have been used for ATC, but these do not provide any significant reduction of the overall mortality rate. The tumorigenesis, development, dedifferentiation and metastasis of ATC are closely associated with the activation of various tyrosine cascades and inactivation of tumor suppressor genes, including B-Raf proto-oncogene, serine/threonine kinase^V600E, phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α,tumor protein 53 mutations and telomerase reverse transcriptase mutation. These pathways exert their functions individually or through a complex network. Identification of these mutations may provide a deeper understanding of ATC. A variety of tyrosine kinase inhibitors have been successfully employed for controlling ATC growth in vitro and in xenografts. Certain novel compounds are still in clinical trials. Multi-kinase inhibitors provide a novel approach with great potential. This systematic review determined the prevalence of the major genetic alterations and their inhibitors in ATC.

Inhibition of mitochondrial respiration by tigecycline selectively targets thyroid carcinoma and increases chemosensitivity

The role of mitochondria in cancer and mitochondria-targeted therapy has been gaining attention for its effectiveness and selectivity between cancer and normal cells. In line with this notion, our work demonstrates that inducing mitochondrial dysfunction by tigecycline, a FDA-approved antibiotic, selectively targets thyroid cancer and enhances chemosensitivity. We found that tigecycline inhibited proliferation and induced apoptosis in a panel of thyroid cancer cell lines. Consistently, tigecycline inhibited thyroid cancer growth in mice without causing significant toxicity. The combination of tigecycline with paclitaxel achieved greater efficacy than paclitaxel alone in vitro and in vivo. Mechanistically, tigecycline inhibited mitochondrial respiration and ATP reduction through decreasing mitochondrial membrane potential and inhibiting mitochondrial translation, leading to oxidative stress and damage. In contrast, tigecycline was ineffective in mitochondrial respiration-deficient cells, confirming that tigecycline acts on thyroid cancer via inhibiting mitochondrial respiration. Interestingly, although tigecycline inhibited mitochondrial respiration in both thyroid cancer and normal thyroid cells in a similar manner, tigecycline was more effective in thyroid cancer than normal thyroid cells, suggesting that thyroid cancer cells are more dependent on mitochondrial functions than normal thyroid cells. This was supported by our observations that thyroid cancer cells had higher level of mitochondrial biogenesis compared to normal thyroid cells. Our work is the first to demonstrate that the combination of chemotherapy with tigecycline is a potential sensitizing strategy for thyroid cancer treatment. Our findings also highlight the higher dependence of thyroid cancer cells on mitochondrial functions than normal thyroid cells.

Cholesterol and 27-hydroxycholesterol promote thyroid carcinoma aggressiveness

Cholesterol mediates its proliferative and metastatic effects via the metabolite 27-hydroxycholesterol (27-HC), at least in breast and endometrial cancer. We determined the serum lipoprotein profile, intratumoral cholesterol and 27-HC levels in a cohort of patients with well-differentiated papillary thyroid carcinoma (PTC; low/intermediate and high risk), advanced thyroid cancers (poorly differentiated, PDTC and anaplastic thyroid carcinoma, ATC) and benign thyroid tumors, as well as the expression of genes involved in cholesterol metabolism. We investigated the gene expression profile, cellular proliferation, and migration in Nthy-ori 3.1 and CAL-62 cell lines loaded with human low-density lipoprotein (LDL). Patients with more aggressive tumors (high-risk PTC and PDTC/ATC) showed a decrease in blood LDL cholesterol and apolipoprotein B. These changes were associated with an increase in the expression of the thyroid’s LDL receptor, whereas 3-hydroxy-3-methylglutaryl-CoA reductase and 25-hydroxycholesterol 7-alpha-hydroxylase were downregulated, with an intratumoral increase of the 27-HC metabolite. Furthermore, LDL promoted proliferation in both the Nthy-ori 3.1 and CAL-62 thyroid cellular models, but only in ATC cells was its cellular migration increased significantly. We conclude that cholesterol and intratumoral accumulation of 27-HC promote the aggressive behavior process of PTC. Targeting cholesterol metabolism could be a new therapeutic strategy in thyroid tumors with poor prognosis.

Activation of the IGF Axis in Thyroid Cancer: Implications for Tumorigenesis and Treatment

The Insulin-like growth factor (IGF) axis is one of the best-established drivers of thyroid transformation, as thyroid cancer cells overexpress both IGF ligands and their receptors. Thyroid neoplasms encompass distinct clinical and biological entities as differentiated thyroid carcinomas (DTC)-comprising papillary (PTC) and follicular (FTC) tumors-respond to radioiodine therapy, while undifferentiated tumors-including poorly-differentiated (PDTC) or anaplastic thyroid carcinomas (ATCs)-are refractory to radioactive iodine and exhibit limited responses to chemotherapy. Thus, safe and effective treatments for the latter aggressive thyroid tumors are urgently needed. Despite a strong preclinical rationale for targeting the IGF axis in thyroid cancer, the results of the available clinical studies have been disappointing, possibly because of the crosstalk between IGF signaling and other pathways that may result in resistance to targeted agents aimed against individual components of these complex signaling networks. Based on these observations, the combinations between IGF-signaling inhibitors and other anti-tumor drugs, such as DNA damaging agents or kinase inhibitors, may represent a promising therapeutic strategy for undifferentiated thyroid carcinomas. In this review, we discuss the role of the IGF axis in thyroid tumorigenesis and also provide an update on the current knowledge of IGF-targeted combination therapies for thyroid cancer.

miR-206 inhibits thyroid cancer proliferation and invasion by targeting RAP1B

Thyroid cancer (TC) is one of the primary tumors arisen from endocrine system. The purpose of this study was to investigate the underlying mechanism by which RAP1B (Ras-related protein Rap-1b) modulates microRNA (miR)-206 related effects on TC cells. Expression of miR-206 and RAP1B was analyzed in cells and tissues. miR-206 mimics or inhibitors and RAP1B vector were used in functional experiments to investigate the effects of miR-206 and RAP1B on cell activities including proliferation, migration, and invasion. Luciferase assay was performed to explore the association between miR-206 and RAP1B. The influence of miR-206 on tumorigenesis of TC cells was investigated using an ex vivo model. Our results demonstrated the reduce of miR-206 in TC tissues and cell lines in which RAP1B was increased. Overexpression of miR-206 significantly inhibited the functional capacities of TPC-1 cells including proliferation, invasion, and migration, most likely, through reducing the expression of RAP1B. Xenograft experiment showed that increased miR-206 could effectively inhibit the tumorigenesis of TC cells. Our study showed that miR-206 negatively regulated cell activities of proliferation, invasion, and migration in TC via suppressing RAP1B expression, suggesting that miR-206 exerts a vital role in TC.

Antiproliferative Effects of Cynaropicrin on Anaplastic Thyroid Cancer Cells

BACKGROUND

The sesquiterpene lactone cynaropicrin, a major constituent of the artichoke leaves extracts, has shown several biologic activities in many preclinical experimental models, including anti-proliferative effects.

OBJECTIVE

Herein we evaluated the effects of cynaropicrin on the growth of three human anaplastic thyroid carcinoma cell lines, investigating the molecular mechanism underlying its action.

METHOD

MTT assay was used to evaluate the viability of CAL-62, 8505C and SW1736 cells, and flow cytometry to analyse cell cycle distribution. Western blot was performed to detect the levels of STAT3 phosphorylation and NFkB activation. Antioxidant effects were analyzed by measuring the reactive oxygen species and malonyldialdehyde dosage was used to check the presence of lipid peroxidation.

RESULTS

Viability of CAL-62, 8505C and SW1736 cells was significantly reduced by cynaropicrin in a dose- and time-dependent way, with an EC50 of about 5 µM observed after 48 h of treatment with the compound. Cellular growth inhibition was accompanied both by an arrest of the cell cycle, mainly in the G2/M phase, and the presence of a significant percentage of necrotic cells. After 48 h of treatment with 10 µM of cynaropicrin, a reduced nuclear expression of NFkB and STAT3 phosphorylation were also revealed. Moreover, we observed an increase in lipid peroxidation, without any significant effect on the reactive oxygen species production.

CONCLUSION

These results demonstrate that cynaropicrin reduces the viability and promotes cytotoxic effects in anaplastic thyroid cancer cells associated with reduced NFkB expression, STAT3 phosphorylation and increased lipid peroxidation. Further characterization of the properties of this natural compound may open the way for using cynaropicrin as an adjuvant in the treatment of thyroid cancer.

Integrated Bioinformatics Analysis of Master Regulators in Anaplastic Thyroid Carcinoma

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive and rapidly lethal tumors. However, limited advances have been made to prolong the survival and to reduce the mortality over the last decades. Therefore, identifying the master regulators underlying ATC progression is desperately needed. In our present study, three datasets including GSE33630, GSE29265, and GSE65144 were retrieved from Gene Expression Omnibus with a total of 32 ATC samples and 78 normal thyroid tissues. A total of 1804 consistently changed differentially expressed genes (DEGs) were identified from three datasets. KEGG pathways enrichment suggested that upregulated DEGs were mainly enriched in ECM-receptor interaction, cell cycle, PI3K-Akt signaling pathway, focal adhesion, and p53 signaling pathway. Furthermore, key gene modules in PPI network were identified by Cytoscape plugin MCODE and they were mainly associated with DNA replication, cell cycle process, collagen fibril organization, and regulation of leukocyte migration. Additionally, TOP2A, CDK1, CCNB1, VEGFA, BIRC5, MAPK1, CCNA2, MAD2L1, CDC20, and BUB1 were identified as hub genes of the PPI network. Interestingly, module analysis showed that 8 out of 10 hub genes participated in Module 1 network and more than 70% genes of Module 2 consisted of collagen family members. Notably, transcription factors (TFs) regulatory network analysis indicated that E2F7, FOXM1, and NFYB were master regulators of Module 1, while CREB3L1 was the master regulator of Module 2. Experimental validation showed that CREB3L1, E2F7, and FOXM1 were significantly upregulated in ATC tissue and cell line when compared with normal thyroid group. In conclusion, the TFs regulatory network provided a more detail molecular mechanism underlying ATC occurrence and progression. TFs including E2F7, FOXM1, CREB3L1, and NFYB were likely to be master regulators of ATC progression, suggesting their potential role as molecular therapeutic targets in ATC treatment.

Proteomic analysis of the papillary thyroid microcarcinoma

OBJECTIVE

The present study applied iTRAQ and LC-MS/MS techniques for proteome analysis and compared data between specimens of papillary thyroid microcarcinoma (PTMC) vs appropriate controls, in order to investigate the mechanisms underlying the invasion and metastasis process in PTMC development.

MATERIALS AND METHODS

Fresh-tissue specimens were collected from 40 patients with thyroid disease who underwent surgical treatment. Specimens were divided into four groups: normal histology (NH; n=8), benign thyroid tumor (BTT; n=10), classic PTMC with lymph node metastasis (PTC-LNM⁽⁺⁾; n=11), and classic PTMC without lymph node metastasis (PTC-LNM^(-); n=11). Proteomic studies were conducted on PTMC tissue samples without capsule invasion and with tumor diameter ranging from 0.5cm to 1cm, so as to focus the study on PTMC development excluding metastasis.

RESULTS

A total of 8036 proteins were identified in the four groups. Based on protein function analysis, proteins that might be associated with PTMC invasion and metastasis were screened: alpha-actinin-1, alpha-1-antitrypsin, hepatoma-derived growth factor (HDGF), high-mobility group protein HMGI-C, and carbonic anhydrase 4. In addition, proteins involved in the focal adhesion pathway were examined. Immunohistochemistry confirmed the reliability of the iTRAQ results and the universality of differentially expressed proteins. The data showed that HDGF and high-mobility group protein HMGI-C are up-regulated in PTMC and that the focal adhesion pathway that promotes PTMC LNM is activated.

CONCLUSIONS

These findings provide insight into the mechanisms underlying PTMC invasion and metastasis.

Safety of Tyrosine Kinase Inhibitors in Patients With Differentiated Thyroid Cancer: Real-World Use of Lenvatinib and Sorafenib in Korea

Background: Thyroid cancer has become the most common cancer in Korea. Generally, thyroid cancer patients have a good prognosis; however, 15-20% of patients experience recurrence or distant metastasis or are refractory to standard treatment. We assessed the safety of sorafenib and lenvatinib in patients with advanced or metastatic radioactive iodine-refractory differentiated thyroid cancers (DTC) consecutively treated at a tertiary center in South Korea. Methods: We retrospectively reviewed the charts of all consecutive patients with DTC treated during ≥6 months with lenvatinib (February 2016-April 2018) and sorafenib (January 2014-April 2018) at Gangnam Severance Hospital. Patients were treated according to the prescribing information of each drug and were followed up for 2 months. We evaluated the adverse events (AEs) reported with each drug. Results: A total of 71 medical records (lenvatinib, n = 23; sorafenib, n = 48) were reviewed. The most common histological types were papillary thyroid cancer (69.0%) and follicular thyroid cancer (22.5%). All patients (n = 23) started lenvatinib at a dose of 20 mg; 41.7% of sorafenib-treated patients received an initial dose of 800 mg daily. Four (17.4%) lenvatinib-treated patients and 26 (54.2%) sorafenib-treated patients required treatment discontinuation. The most common AEs of any grade in the lenvatinib group were diarrhea (82.6%), hypertension (78.3%), hand-foot skin reaction (56.5%), weight loss (52.2%), proteinuria (47.8%), and anorexia (43.5%). In the sorafenib group, these were hand-foot skin reaction (87.5%), diarrhea (62.5%), anorexia (60.4%), alopecia (56.3%), mucositis (52.1%), weight loss and generalized weakness (each, 50%), and hypertension (43.8%). The incidence of hand-foot skin reaction, alopecia, and rash of any grade was significantly lower (P = 0.003, P = 0.017, and P = 0.017) in patients treated with lenvatinib compared with those treated with sorafenib. The incidence of hypertension, QT prolongation, and proteinuria of any grade was significantly higher (P = 0.006, P = 0.038, and P < 0.001) in patients treated with lenvatinib compared with those treated with sorafenib. Seven deaths occurred, which were attributed to disease progression. Conclusions: No new safety concerns were identified for either drug. Most AEs were managed with dose modification and medical therapy. AEs such as hypertension and proteinuria warrant close monitoring.

Molecular aberrations and signaling cascades implicated in the pathogenesis of anaplastic thyroid cancer

Anaplastic Thyroid Cancer (ATC) accounts for >40% thyroid cancer-related deaths and has a dismal prognosis. In the past decade, significant efforts have been made towards understanding the pathogenesis of this disease and developing novel therapeutics. Unfortunately, effective treatment is still lacking and a more thorough understanding of ATC pathogenesis may provide new opportunities to improve ATC therapeutics. This review provides insights into ATC clinical presentation and pathology, and the putative role of genetic aberrations and alterations in molecular signaling pathways in ATC pathogenesis. We reviewed prevalent mutations, chromosomal abnormalities and fusions, epigenetic alterations and dysregulations in ATC, and highlighted several signaling cascades which appeared to be integral to ATC pathogenesis. Moreover, these features offer insights into de-differentiated, aggressive and drug-resistant phenotype of ATC, and thus may help in exploring potential new molecular targets for developing novel therapeutics.

The Emerging Role of Insulin Receptor Isoforms in Thyroid Cancer: Clinical Implications and New Perspectives

Thyroid cancer (TC) is the most common endocrine tumor. Although the majority of TCs show good prognoses, a minor proportion are aggressive and refractory to conventional therapies. So far, the molecular mechanisms underlying TC pathogenesis are incompletely understood. Evidence suggests that TC cells and their precursors are responsive to insulin and insulin-like growth factors (IGFs), and often overexpress receptors for insulin (IR) and IGF-1 (IGF-1R). IR exists in two isoforms, namely IR-A and IR-B. The first binds insulin and IGF-2, unlike IR-B, which only binds insulin. IR-A is preferentially expressed in prenatal life and contributes to development through IGF-2 action. Aggressive TC overexpresses IR-A, IGF-2, and IGF-1R. The over-activation of IR-A/IGF-2 loop in TC is associated with stem-like features and refractoriness to some targeted therapies. Importantly, both IR isoforms crosstalk with IGF-1R, giving rise to the formation of hybrids receptors (HR-A or HR-B). Other interactions have been demonstrated with other molecules such as the non-integrin collagen receptor, discoidin domain receptor 1 (DDR1), and the receptor for the hepatocyte growth factor (HGF), Met. These functional networks provide mechanisms for IR signaling diversification, which may also exert a role in TC stem cell biology, thereby contributing to TC initiation and progression. This review focuses on the molecular mechanisms by which deregulated IR isoforms and their crosstalk with other molecules and signaling pathways in TC cells and their precursors may contribute to thyroid carcinogenesis, progression, and resistance to conventional treatments. We also highlight how targeting these alterations starting from TC progenitors cells may represent new therapeutic strategies to improve the clinical management of advanced TCs.

Integrated analysis of long noncoding RNA interactions reveals the potential role in progression of human papillary thyroid cancer

Recent scientific evidence has suggested that long noncoding RNAs (lncRNAs) play an important part in tumorigenesis as an important member of competing endogenous RNAs (ceRNAs). Hundreds of RNA sequence data and relevant clinic information are freely accessible in The Cancer Genome Atlas (TCGA) datasets. However, the role of cancer‐related lncRNAs in papillary thyroid cancer (PTC) is not fully understood yet. In this study, we identified 461 RNA sequencing data from TCGA. Subsequently, 45 lncRNAs, 21 miRNAs, and 78 mRNAs were chosen to construct a ceRNA network of PTC. Then, we analyzed the correlation between these 45 PTC‐specific lncRNAs and clinic features and patient outcome. Thirty‐seven of these lncRNAs were found to be closely related to age, race, gender, lymph node metastasis, TNM staging system, and patient outcome. Additionally, three of them were linked to PTC patient overall survival. Eventually, we selected eight lncRNAs randomly and performed quantificational real‐time polymerase chain reaction (qRT‐PCR) in 28 newly diagnosed patients with PTC to verify the reliability of the above results. The results of qRT‐PCR are totally in agreement with the bioinformatics analysis. Additionally, it was found that HAND2‐AS1 was negatively related to tumor size (P < 0.05). The results were consistent with the bioinformatics analysis in TCGA. Taken together, we identified the differentially expressed lncRNAs and constructed a PTC ceRNA network. The study provides a new perspective and supplement for our understanding of lncRNAs in PTC development and reveals potential diagnostic and prognostic markers in PTC.