Follicular Thyroid Carcinoma Cell Research Articles

Inhibiting β-catenin expression promotes efficiency of radioiodine treatment in aggressive follicular thyroid cancer cells probably through mediating NIS localization.

The present study investigated whether the efficacy of radioiodine therapy towards aggressive thyroid cancer cells was affected by β-catenin activity and associated with sodium/iodine symporter (NIS) localization. Human thyroid cancer cell line follicular thyroid carcinoma (FTC) 133 was endowed with aggressiveness by HIF-1α or β-catenin overexpression. The protein amount and subcellular localization of NIS, and the radioiodine uptake capacity were detected in the cells, as well as in cells subsequently undergoing β-catenin knockdown. Xenograft experiments were conducted to compare the tumor growth ability and responsiveness to radioactive treatment among HIF-1α and β-catenin overexpressing FTC cells, respectively with or without β-catenin knockdown. β-catenin increased upon HIF-1α overexpression, but not vice versa. This signal axis would prompt metastatic propensity in FTC cells, and translocate NIS from cytomembrane to cytoplasm. Consistently the radioiodine uptake capacity in the cells decreased obviously. Knockdown of β-catenin reversed all these changes. Furthermore, the xenograft experiments showed that radioiodine treatment could thoroughly suppress tumor growth ability of aggressive FTC cells only if the HIF-1α-induced β-catenin activation was disrupted by β-catenin knockdown. β-catenin nuclear translocation in tumor cells was accompanied by abnormal subcellular localization of NIS. Moreover, we found that only after inhibiting β-catenin expression, can the radioiodine treatment promote apoptosis other than repress proliferation and survival in xenograft tumor cells. In conclusion, aggressive FTC cells overexpressing HIF-1α will be fully cracked down by radioiodine therapy once β-catenin expression is inhibited, and regulated localization of NIS may account for underlying mechanisms.

Promotion of metastasis of thyroid cancer cells via NRP-2-mediated induction.

Tumor-node-metastasis is one of the leading causes of morbidity and mortality in thyroid cancer patients. Upregulation of vascular endothelial growth factor-C (VEGF-C) increases the migratory ability of thyroid cancer cells to lymph nodes. Expression of neuropilin-2 (NRP-2), the co-receptor of VEGF-C, has been reported to be correlated with lymph node metastasis in human thyroid cancer. The present study investigated the role of VEGF-C/NRP-2 signaling in the regulation of metastasis of two different types of human thyroid cancer cells. The results indicated that the VEGF-C/NRP-2 axis significantly promoted the metastatic activities of papillary thyroid carcinoma cells through the activation of the mitogen-activated protein kinase (MAPK) kinase (MEK)/extracellular signal-regulated kinase and p38 MAPK signaling cascades. However, neither MEK or p38 MAPK inhibitors produced significant inhibition of the migratory activity and invasiveness regulated by the VEGF-C/NRP-2 axis in follicular thyroid carcinoma cells. Finally, VEGF-C/NRP-2-mediated invasion and migration of thyroid cancer cells required the expression of NRP-2. The present results demonstrate that the promotion of metastasis by VEGF-C is mainly due to the upregulation of NRP-2 in thyroid cancer cells, and this metastatic activity regulated by the VEGF-C/NRP-2 axis provides further insight into the process of tumor metastasis.

Molecular genetics of follicular cell thyroid carcinoma

Thyroid cancer is the most frequent endocrine malignancy. In the most cases thyroid cancer arises from follicular cells. Diagnosis of the cancer is based on the cytological analysis of fine needle aspiration biopsy of thyroid nodes. But the accuracy of the cytological diagnosis is about 80% that leads to the false positive and false negative cases and wrong strategy of treatment. Identification of genetic and epigenetic markers in the biopsies will allow to improve diagnostic accuracy. This article describes mutations, aberrant DNA methylation and abnormal microRNA expression constituting the core of molecular genetics of follicular cell thyroid cancer. The mutations given in the article includes point mutations, fusions and copy number variation. Besides frequent and well described driver mutations in genes of МАРK, PI3K/Akt and Wnt signaling pathways, as well as TP53 and TERT genes, we introduce here less frequent mutations appeared in the literature during the past two years. In addition the article contains examples of diagnostic panels applying these markers.

PVALB diminishes [Ca2+] and alters mitochondrial features in follicular thyroid carcinoma cells through AKT/GSK3β pathway.

We have identified previously a panel of markers (C1orf24, ITM1 and PVALB) that can help to discriminate benign from malignant thyroid lesions. C1orf24 and ITM1 are specifically helpful for detecting a wide range of thyroid carcinomas, and PVALB is particularly valuable for detecting the benign Hürthle cell adenoma. Although these markers may ultimately help patient care, the current understanding of their biological functions remains largely unknown. In this article, we investigated whether PVALB is critical for the acquisition of Hürthle cell features and explored the molecular mechanism underlying the phenotypic changes. Through ectopic expression of PVALB in thyroid carcinoma cell lines (FTC-133 and WRO), we demonstrated that PVALB sequesters free cytoplasmic Ca(2+), which ultimately lowers calcium levels and precludes endoplasmic reticulum (ER) Ca(2+) refilling. These results were accompanied by induced expression of PERK, an ER stress marker. Additionally, forced expression of PVALB reduces Ca(2+) inflow in the mitochondria, which can in turn cause changes in mitochondria morphology, increase mitochondria number and alter subcellular localization. These findings share striking similarity to those observed in Hürthle cell tumors. Moreover, PVALB inhibits cell growth and induces cell death, most likely through the AKT/GSK-3β. Finally, PVALB expression coincides with Ca(2+) deposits in HCA tissues. Our data support the hypothesis that the loss of PVALB plays a role in the pathogenesis of thyroid tumors.

Transcriptional regulation of the potential tumor suppressor ABI3 gene in thyroid carcinomas: interplay between methylation and NKX2-1 availability.

We previously reported that ABI3 expression was decreased in thyroid cancer tissues and that ectopic expression of ABI3 in a follicular thyroid carcinoma cell line delayed cell cycle progression and inhibited cell proliferation, invasion, migration and tumor formation in athymic mice. These data indicated that ABI3 is a tumor suppressor gene; however the mechanism through which ABI3 is silenced in thyroid carcinomas is unknown. We here show that treatment of four follicular thyroid carcinoma cell lines with 5-aza-dC induced demethylation of a specific region of the ABI3 promoter and restored ABI3 expression. In contrast, 5-aza-dC treatment did not restore ABI3 expression in a non-thyroid cell line, suggesting a tissue-specific regulation. We additionally show that 8 CpG sites located within the ABI3 promoter are hypermethylated in most thyroid carcinoma samples and the degree of methylation correlated with ABI3 expression. Narrowing the region to specific CpG sites, the CpG4-6 sites showed the largest difference between benign and malignant lesions. In silico analysis revealed that these CpG sites flank a canonical binding site for NKX2-1, a thyroid specific transcriptional factor. Analysis of thyroid samples shows a correlation between NKX2-1 and ABI3 expression. In vitro assays demonstrate that NKX2-1 was required for ABI3 expression. Luciferase assay further confirmed the promoter activity of this region, which was increased when the cells were co-transfected with NKX2-1. Our study shows that the transcriptional silencing of ABI3 in cancer cells occurs via methylation and uncovered a previously unrecognized role for NKX2-1 in the regulation of ABI3.

Follicular thyroid carcinoma but not adenoma recruits tumor-associated macrophages by releasing CCL15.

BackgroundThe differential diagnosis of follicular thyroid carcinoma (FTC) and follicular adenoma (FA) before surgery is a clinical challenge. Many efforts have been made but most focusing on tumor cells, while the roles of tumor associated macrophages (TAMs) remained unclear in FTC. Here we analyzed the differences between TAMs in FTC and those in FA.MethodsWe first analyzed the density of TAMs by CD68 immunostaining in 59 histologically confirmed FTCs and 47 FAs. Cytokines produced by FTC and FA were profiled using antibody array, and validated by quantitative PCR. Chemotaxis of monocyte THP-1 was induced by condition medium of FTC cell lines (FTC133 and WRO82-1) with and without anti-CCL15 neutralizing antibody. Finally, we analyzed CCL15 protein level in FTC and FA by immunohistochemistry.ResultsThe average density of CD68+ cells was 9.5 ± 5.4/field in FTC, significantly higher than that in FA (4.9 ± 3.4/field, p < 0.001). Subsequently profiling showed that CCL15 was the most abundant chemokine in FTC compared with FA. CCL15 mRNA in FTC was 51.4-folds of that in FA. CM of FTC cell lines induced THP-1 cell chemotaxis by 33 ~ 77 %, and anti-CCL15 neutralizing antibody reduced THP-1 cell migration in a dose-dependent manner. Moreover, we observed positive CCL15 immunostaining in 67.8 % of FTCs compared with 23.4 % of FAs.ConclusionOur study suggested FTC might induce TAMs infiltration by producing CCL15. Measurement of TAMs and CCL15 in follicular thyroid lesions may be applied clinically to differentiate FTC from FA pre-operation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2114-7) contains supplementary material, which is available to authorized users.

The sonic hedgehog signaling pathway stimulates anaplastic thyroid cancer cell motility and invasiveness by activating Akt and c-Met.

The sonic hedgehog (Shh) pathway is highly activated in thyroid neoplasms and promotes thyroid cancer stem-like cell phenotype, but whether the Shh pathway regulates thyroid tumor cell motility and invasiveness remains unknown. Here, we report that the motility and invasiveness of two anaplastic thyroid tumor cell lines, KAT-18 and SW1736, were inhibited by two inhibitors of the Shh pathway (cyclopamine and GANT61). Consistently, the cell motility and invasiveness was decreased by Shh and Gli1 knockdown, and was increased by Gli1 overexpression in KAT-18 cells. Mechanistic studies revealed that Akt and c-Met phosphorylation was decreased by a Gli1 inhibitor and by Shh and Gli1 knockdown, but was increased by Gli1 overexpression. LY294002, a PI-3 kinase inhibitor, and a c-Met inhibitor inhibited the motility and invasiveness of Gli1-transfected KAT-18 cells more effectively than the vector-transfected cells. Knockdown of Snail, a transcription factor regulated by the Shh pathway, led to decreased cell motility and invasiveness in KAT-18 and SW1736 cells. However, key epithelial-to-mesenchymal transition (EMT) markers including E-cadherin and vimentin as well as Slug were not affected by cyclopamine and GANT61 in either SW1736 or WRO82, a well differentiated follicular thyroid carcinoma cell line. Our data suggest that the Shh pathway-stimulated thyroid tumor cell motility and invasiveness is largely mediated by AKT and c-Met activation with little involvement of EMT.

ST6GalNAcII mediates tumor invasion through PI3K/Akt/NF-κB signaling pathway in follicular thyroid carcinoma.

Altered sialylation, closely associated with tumor progression and metastasis, has been implicated in human thyroid carcinoma. The present study investigated the alteration in expression of ST6GalNAcII involved in invasion and to clarify the possible mechanism of ST6GalNAcII in the metastasis process in human follicular thyroid carcinoma cell lines. Using real-time PCR, western blot and IHC analysis, ST6GalNAcII differed in three follicular thyroid cancer cell lines (FTC133, primary and FTC238, lung metastasis). It also showed differential expression in follicular thyroid carcinoma and tissue specimens. In addition, we analyzed the PI3K/Akt signaling pathway. The altered expression of ST6GalNAcII corresponded to changed invasive phenotype of FTC-238 and FTC-133 cells in vitro and in vivo. Further studies showed that regulating ST6GalNAcII expression markedly modulated the activity of the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway. Targeting the PI3K/Akt pathway by its specific inhibitor LY294002, or by Akt small interfering RNA (siRNA) resulted in reduced capacity in invasion of FTC-238. In conclusion, taken together, our results imply that ST6GalNAcII activated the invasion in follicular thyroid cancer cells through regulating the activity of PI3K/Akt pathway.

Unveiling a novel biomarker panel for diagnosis and classification of well-differentiated thyroid carcinomas.

Thyroid cancer is the most common human endocrine malignancy with increasing global incidence. Papillary thyroid carcinomas (PTC) and follicular thyroid carcinomas (FTC) are well-differentiated thyroid cancers (WDTC) accounting for 95% of all thyroid cancer cases, with survival rates of almost 100% when diagnosed early. Since PTC and FTC have different modes of metastasis, they require different treatment strategies. Standard diagnosis by fine needle aspiration with cytopathological examination can be inaccurate in approximately 10-30% of all cases and difficult to definitively classify as WDTC. Currently, there is no single or panel of biomarkers available for thyroid cancer diagnosis and classification. This study identified novel biomarkers for thyroid cancer diagnosis and classification using proteomics, which may be translated into a biomarker panel for clinical application. Two-dimensional SDS-PAGE and mass spectrometry were used to identify potential biomarkers in papillary and follicular thyroid carcinoma cell lines, and the biomarkers were validated in five PTC and five FTC tissues, with their adjacent normal tissues from Thai patients. Eight biomarkers could distinguish PTC from normal tissues, namely enolase 1, triose phosphate isomerase, cathepsin D, annexin A2, cofilin 1, proliferating cell nuclear antigen (PCNA), copine 1 and heat shock protein 27 kDa (HSP27). These biomarkers can also discriminate FTC from normal tissues, except for annexin A2. On the contrary, annexin A2, cofilin 1, PCNA and HSP27 can be used to classify the types of WDTC. These findings have potential for use as a novel multi-marker panel for more accurate diagnosis and classification to better guide physicians on thyroid cancer treatment. Moreover, our results suggest the involvement of proteins in cell growth and proliferation, and the p53 pathway in the carcinogenesis of WDTC, which may lead to targeted therapy for thyroid cancer.

MiR-4299 mediates the invasive properties and tumorigenicity of human follicular thyroid carcinoma by targeting ST6GALNAC4.

Altered sialylation is closely associated with tumor progression and invasiveness. Micro-RNAs endogenous regulators of gene expression have been implicated in human thyroid carcinoma invasiveness. The objective of this study is to examine the alterations of miR-4299 and ST6GALNAC family in human follicular thyroid carcinoma during metastatic process. qRT-PCR showed the differential expressional profiles of miR-4299 and ST6GALNAC family in three kinds of thyroid cell lines (FTC-133,FTC-238, Nthy-ori 3-1) and clinical tissue specimens(malignant and borderline). The altered expression levels of ST6GALNAC4 were corresponding to invasive phenotypes of FTC-133 and FTC-238 cells both in vitro and in vivo. Further date indicated that miR-4299 regulated tumor progression and invasiveness by directly targeting ST6GALNAC4. This study implies the potential therapeutic application of miR-4299 and ST6GALNAC4 in modulating the invasion and tumorigenicity of follicular thyroid carcinoma cell.

The impact of CLAUDIN-1 on follicular thyroid carcinoma aggressiveness.

CLAUDIN-1 belongs to the family of transmembrane tight junction proteins tightening the paracellular cleft of epithelial cells. In human malignancies, CLAUDIN-1 is often dysregulated and located in subcellular compartments, particularly in the nucleus where it may influence cellular behaviour. Here, we studied CLAUDIN-1 in relation to the biological characteristics of follicular thyroid carcinoma (FTC). CLAUDIN-1 immuno-staining showed loss of membrane expression and increased nuclear CLAUDIN-1 localization in FTC metastases. CLAUDIN-1 function was further investigated in two different follicular thyroid carcinoma cell lines: FTC-133 isolated from a regional lymph node metastasis and FTC-238 derived from a lung metastasis. In both cell lines CLAUDIN-1 expression was demonstrated in the cell nuclei with a significantly higher protein expression in FTC-238 compared to FTC-133 cells. Interestingly, in vitro scratch assay revealed enriched nuclear CLAUDIN-1 expression near the scratch. Furthermore, the increase of the pathogenic character of FTC-133 cells by RASV12 transfection was associated with elevated CLAUDIN-1 expression and enhanced cell migration, invasion and proliferation. Likewise over-expression of nuclear CLAUDIN-1 in FTC-133 cells resulted in increased cell migration and invasion. Conversely, CLAUDIN-1 downregulation in FTC-238 cells by siRNA resulted in decreased cell migration and invasion and was accompanied by reduced phosphoPKC expression. Moreover, activation and inhibition of PKC resulted in CLAUDIN-1 up- and downregulation in FTC cells respectively. These data suggest an impact of CLAUDIN-1 on follicular thyroid carcinoma aggressiveness, which could potentially be influenced by PKC activity.

MicroRNA-106b-mediated down-regulation of C1orf24 expression induces apoptosis and suppresses invasion of thyroid cancer.

We previously showed that C1orf24 expression is increased in thyroid carcinomas. Nonetheless, the mechanism underlying C1orf24 deregulation is not fully understood. It has been widely demonstrated that microRNAs are involved in post-transcriptional gene regulation in several diseases, including cancer. Using in silico prediction approach, five microRNAs that bind to the 3'-untranslated region (3'-UTR) of C1orf24 were identified. The expression of two selected microRNAs (miR-17-5p, miR-106b) and the expression of C1orf24 were tested in 48 benign and malignant thyroid lesions and in five thyroid carcinoma cell lines. miR-106b was down-regulated in thyroid cancer specimens and thyroid carcinoma cell lines, while C1orf24 expression was markedly increased. To demonstrate that miR-106b reduces C1orf24 expression, follicular (WRO) and papillary (TPC1) thyroid carcinoma cell lines were transiently transfected with miR-106b mimic. Ectopic expression of the miR-106b mimic significantly inhibits C1orf24 mRNA and protein expression in both WRO and TPC1 cells. Dual-luciferase report assays demonstrated that miR-106b directly targets C1orf24 by binding its 3'-UTR. Moreover, miR-106b-mediated down-regulation of C1orf24 expression increased apoptosis and inhibited migration. We additionally demonstrated that siRNA against C1orf24 significantly decreased its expression, inhibited cell migration and cell cycle progression while induced apoptosis. In summary, our findings not only provide new insights into molecular mechanism associated with C1orf24 overexpression in thyroid carcinomas but also show that C1orf24 might increase proliferation and cell migration. Thus, decreasing C1orf24 levels, by restoring miR-106b function, may have therapeutic implications.

Post-transplant diagnosis of hereditary leiomyomatosis and renal cell carcinoma syndrome in a kidney donor.

A 58-year-old woman developed multiple, clustered, pink, painless, papules on her upper extremities, back and flank (Figure ​(Figure1A–C).1A–C). Her past medical history was notable for multiple uterine leiomyomata, follicular thyroid carcinoma and cutaneous basal cell carcinomas. The patient had donated her left kidney one year after the skin lesions developed. Pertinent family history included uterine leiomyomata in her mother, uterine leiomyomata and two miscarriages in her maternal grandmother, and a maternal cousin with uterine cancer. A biopsy of a representative skin lesion demonstrated clustered fascicles of benign, spindle-shaped smooth muscle cells within the dermis, consistent with the diagnosis of cutaneous leiomyoma (Figure ​(Figure2).2). Based on these findings, the patient was referred for genetic testing and counseling given suspicion for hereditary leiomyomatosis and renal cell carcinoma (HLRCC). She was found to harbor a germline missense mutation (Glycine397Arginine) in the fumarate hydratase (FH) gene on chromosome one, confirming this diagnosis. Further investigation revealed the same mutation in the patient's mother but the family history was negative for renal cell carcinoma (RCC). Given the risk of internal malignancy with this condition, routine surveillance of her remaining kidney with alternating ultrasound and MRI every six months was initiated and has remained negative to date. In addition, the recipient of the patient's transplanted kidney was notified of her donor's diagnosis and also continues to undergo imaging surveillance. Fig. 1. Clinical photograph. (A) Multiple, clustered, pink to brown-colored painless papules present on the extensor surface of her left upper extremity. One of the representative lesions was biopsied. (B) Higher magnification imaging illustrates another collection ... Fig. 2. Skin histopathology. Clustered fascicles of benign, spindle-shaped cells showing smooth muscle differentiation on hematoxylin and eosin (H&E) stain (×10 magnification). HLRCC is an autosomal dominant condition characterized by the development of multiple cutaneous and uterine leiomyomata as well as a predisposition for RCC. This condition is caused by a germline mutation in a single copy of the FH gene [1]. Up to 6% of individuals from families affected by germline FH mutations develop RCC [1]. In addition, studies suggest that the RCCs arising in HLRCC may behave more aggressively than those arising in other RCC predisposition syndromes [2]. The scenario encountered in our case is notable in that the donor patient's hereditary predisposition for RCC was identified only after having donated her kidney, despite the cutaneous manifestations of her condition developing 1 year prior to the donation. The added risk to the recipient of developing a de novo malignancy in the transplanted kidney due to a donor-derived germline predisposition is unknown; there have been no such reported cases. Given the rarity of familial cancer syndromes, routine genetic screening of donors or their organs for germline mutations is not currently performed. However, it is known that the overall incidence of de novo malignancies after kidney transplantation ranges from 6–11%, with cutaneous squamous and basal cell carcinomas, thyroid carcinomas and malignancies of the native kidney among the most common [3, 4]. Taken together, our case emphasizes the importance of a thorough physical examination and an awareness of the dermatologic manifestations of hereditary cancer predisposition syndromes.

Recurrence of Differentiated Thyroid Carcinoma During Full TSH Suppression: Is the Tumor Now Thyroid Hormone Dependent?

Well-standardized primary treatment and long-term management of differentiated thyroid carcinoma (DTC) include lowering or suppression of host thyrotropin (TSH) with exogenous L-thyroxine (T4). This treatment recognizes the trophic action of TSH on DTC cells. Suppression of endogenous TSH with T4 is continued in recurrent disease. However, T4 can induce proliferation of follicular and papillary thyroid carcinoma cell lines and of other human carcinoma cells. The proliferative mechanism is initiated at a cell surface receptor for T4 on integrin αvβ3, a receptor by which the hormone also inhibits p53-dependent apoptosis in tumor cells. In recurrent DTC with satisfactory suppression of endogenous TSH, we discuss here the possibility that the tumor is no longer TSH dependent and that T4 has become a critical growth factor for the cancer.

Abstract 3059: Detection and characterization of circulating tumor cells by imaging flow cytometry

Abstract Introduction The clinical utility of circulating tumour cell enumeration as a prognostic indicator has been demonstrated in numerous carcinomas. However, poor quality images and limited characterisation available on the main platform used for CTC enumeration hamper the exploitation of CTCs in other areas of clinical oncology. Additionally, the reliance on the expression of EpCAM for the detection of CTCs limits detection of cells that have undergone epithelial/mesenchymal transition, and may therefore not directly detect metastatic precursor cells. In contrast, flow cytometric methods of CTC enumeration which allow multiple markers to be used simultaneously, are more sensitive than microscopy methods, but carry the caveat that cellular debris may not be resolvable from cells with a high degree of confidence. Our aim was to establish the sensitivity of detection of CTCs by imaging flow cytometry. Methods ML-1 follicular thyroid carcinoma cells were spiked into 4 ml whole blood from healthy volunteers collected into EDTA vacutainers to give concentrations of 500, 50 or 5 cells per ml. The samples were subjected to red blood cell lysis and fixation. CD45 positive leukocytes were then depleted by immuno-magnetism using a CD45 antibody. The remaining cells were permeabilised and stained with flurochrome conjugated primary antibodies to thyroglobulin, sodium iodide symporter, EpCam, cytokeratin, vimentin and CD45 as well as DAPI as a nuclear stain. The stained cells were processed using an imaging flow cytometer. Results Preliminary experiments to validate the specificity of the antibodies indicated the potential importance of heterogeneity as revealed by multi parameter staining. Only 8 ± 3.6% of ML-1 cells with a mesenchymal phenotype (EpCAM -ve/Vimentin+ve) were in G2 compared with 32 ± 8.7% cells from the same culture with a more epithelial (EpCAM +ve/Vimentin-ve) phenotype (mean and SD of three independent experiments, p = 0.012 T-test). Recovery experiments following red cell lysis and CD45 depletion of spiked cell samples gave &amp;gt;90% depletion of leukocytes and 48 ± 5%, 56 ± 15% and 78 ± 32% recovery at spiking densities of 500, 50 and 5 cells per ml respectively (mean and SD of three independent experiments). Discussion The method described allows the capture of multi-parameter high quality fluorescent images of extremely rare cell populations in a whole blood matrix and we are currently applying it to clinical samples derived from cancer patients and healthy volunteers. The method is also readily transferable to the detection of CTCs from other tumours by the substitution of tumour/tissue specific antibodies and optical space remains for the introduction of two additional probes. We will exploit this by incorporating probes for pharmacodynamic biomarkers specific to compounds in early phase clinical trials, thus allowing simultaneous PD assays in CTCs as a liquid biopsy and residual haematopoietic cells as a surrogate tissue. Citation Format: Barry Dent, Rachel L. O'Donnell, Laura F. Ogle, Emma D. Rourke, Hamsavardhini P. Ramesh, Maddie Moat, Nick Hayes, Ujjal K. Mallick, Felicity EB May, Helen L. Reeves, Nicola J. Curtain, Richard J. Edmondson, Alan V. Boddy, Ruth Plummer, David Jamieson. Detection and characterization of circulating tumor cells by imaging flow cytometry. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3059. doi:10.1158/1538-7445.AM2014-3059

Clinical, pathologic, and immunohistochemical prognostic factors in dogs with thyroid carcinoma.

BackgroundPrognostic markers for dogs with thyroid tumors are limited.Hypothesis/ObjectivesTo identify clinical, pathologic, and immunohistochemical prognostic factors for dogs with thyroid tumors.AnimalsSeventy dogs with thyroid neoplasia.MethodsRetrospective study. Dogs with thyroid neoplasia were included when follow‐up information and formalin‐fixed paraffin‐embedded tumor samples were available. Immunohistochemistry (IHC) was performed for thyroglobulin, calcitonin, Ki‐67, and E‐cadherin. Correlation of tumor variables (diameter, volume, localization, scintigraphic uptake, thyroid function, IHC) with local invasiveness and metastatic disease was performed on all tumor samples. Forty‐four dogs treated by thyroidectomy were included in a survival analysis.ResultsFifty dogs (71%) had differentiated follicular cell thyroid carcinoma (dFTC) and 20 (29%) had medullary thyroid carcinoma (MTC). At diagnosis, tumor diameter (P = .007; P = .038), tumor volume (P = .020), tumor fixation (P = .002), ectopic location (P = .002), follicular cell origin (P = .044), and Ki‐67 (P = .038) were positively associated with local invasiveness; tumor diameter (P = .002), tumor volume (P = .023), and bilateral location (P = .012) were positively associated with presence of distant metastases. Forty‐four dogs (28 dFTC, 16 MTC; stage I–III) underwent thyroidectomy. Outcome was comparable between dogs with dFTC and MTC. Macroscopic (P = .007) and histologic (P = .046) vascular invasion were independent negative predictors for disease‐free survival. Although time to presentation, histologic vascular invasion and Ki‐67 were negatively associated with time to metastases, and time to presentation was negatively associated with time to recurrence, no independent predictors were found. E‐cadherin expression was not associated with outcome.Conclusions and Clinical ImportancePrognostic factors have been identified that provide relevant information for owners and clinicians.

Upregulation of the PI3K/Akt pathway in the tumorigenesis of canine thyroid carcinoma.

BackgroundInformation on the genetic events leading to thyroid cancer in dogs is lacking.Hypothesis/ObjectivesUpregulation of the PI3K/Akt pathway has an important role in the tumorigenesis of thyroid carcinoma in dogs.AnimalsFifty‐nine dogs with thyroid carcinoma and 10 healthy controls.MethodsQuantitative RT‐PCR was performed for VEGFR‐1, VEGFR‐2, EGFR, PIK3CA, PIK3CB, PDPK1, PTEN, AKT1, AKT2, COX‐2, and CALCA. Mutation analysis was performed for known hotspots of RAS (N, K, H), PIK3CA, BRAF, RET, and for the entire coding region of PTEN.ResultsForty‐three dogs (73%) had follicular cell thyroid carcinoma (FTC) and 16 dogs (27%) had medullary thyroid carcinoma (MTC). The relative mRNA expressions of VEGFR‐1 (P < .001), VEGFR‐2 (P = .002), PDPK1 (P < .001), AKT1 (P = .009), and AKT2 (P < .001) were increased in FTC, and those of EGFR (P < .001), VEGFR‐1 (P = .036), and PIK3CA (P = .019) were increased in MTC when compared to normal thyroid glands. Mutation analysis of K‐RAS identified 2 activating missense mutations, which also have been described in thyroid cancer of humans. A G12R substitution was present in 1 FTC and an E63K substitution was present in 1 MTC. No functional mutations were found in the sequenced regions of H‐RAS, N‐RAS, PIK3CA, BRAF, RET, and PTEN.Conclusions and Clinical ImportanceThe increased expression of several genes associated with PI3K/Akt signaling suggests the involvement of this pathway in the pathogenesis of thyroid carcinoma in dogs, warranting further research on pathway activation and gene amplification. The mutations most frequently associated with thyroid cancer in humans are rare in dogs.

Prognostic classification of thyroid follicular cell tumors using Ki-67 labeling index: risk stratification of thyroid follicular cell carcinomas.

This review emphasizes that the so-called high-risk thyroid carcinoma is not a distinct tumor entity, but a group of tumors with different histologies. High-grade histological features, such as tumor necrosis, increased mitoses, and nuclear pleomorphism, together with high Ki-67 labeling index (more than 10%), are good indicators of high-risk thyroid carcinoma and suggest a possible risk for anaplastic transformation. This review proposes the stratification of patients with thyroid carcinoma into low-, moderate-, and high-risk groups based on Ki-67 labeling index, which should be useful for the clinical management of patients, even after initial surgery. Currently, both the aggressive variant of papillary carcinoma and poorly differentiated carcinoma are aggressively treated by a completion of total thyroidectomy with prophylactic lymph node dissection followed by radioactive iodine treatment. Therefore, patients with moderate-risk or high-risk thyroid carcinoma based on Ki-67 labeling index should also be considered candidates for this treatment strategy.

Expression of miR-100 and RBSP3 in FTC-133 cells after exposure to 131I.

Sodium iodide ((131)I) therapy for the management of differentiated thyroid cancer is based on the deposition of certain doses of ionizing radiation, which can modulate microRNA (miRNA, miR) expression. Recent studies have suggested that miR-100 is significantly differentially expressed between benign and malignant thyroid tissue samples and modulates retinoblastoma 1 serine phosphates from human chromosome 3 (RBSP3), which is involved in the regulation of cell growth and differentiation. Therefore, the authors tested the hypothesis that a potential mechanism of (131)I treatment affects miR-100, which in turn regulates RBSP3 to modulate cell proliferation in thyroid cancer in vitro. A follicular thyroid carcinoma cell line (FTC-133) was treated with (131)I or transfected with an oligonucleotide (miR-100 mimics, inhibitor, or negative control). Real-time quantitative PCR was used to confirm the expression levels of the miR-100 and RBSP3 mRNAs. Western blot analysis was performed to detect the levels of the RBSP3 protein. The cell cycle was analyzed on a cytofluorimeter by fluorescence-activated cell sorting analysis. RBSP3 protein expression was detected in FTC-133 cells. (131)I treatment inhibited the expression of miR-100 in FTC cells, as assessed by real-time quantitative PCR analysis, whereas it upregulated the RBSP3 mRNA and protein. Overexpression and knockdown experiments indicated that miR-100 repressed the expression of the RBSP3 mRNA by blocking its translation. Overexpression of miR-100 led to the downregulation of the RBSP3 protein and promoted the transition of FTC cells from the G1 to the S phase, as assessed using FACS analysis. (131)I treatment inhibited the expression of miR-100, which modulated RBSP3 in FTC cells. The new mechanism of suppression of the proliferation of FTC cells by I described here might occur through the downregulation of miR-100.

Cowden syndrome-associated germline SDHD variants alter PTEN nuclear translocation through SRC-induced PTEN oxidation.

Germline mutations in the PTEN tumor-suppressor gene and germline variations in succinate dehydrogenase subunit D gene (SDHD-G12S, SDHD-H50R) are associated with a subset of Cowden syndrome and Cowden syndrome-like individuals (CS/CSL) and confer high risk of breast, thyroid and other cancers. However, very little is known about the underlying crosstalk between SDHD and PTEN in CS-associated thyroid cancer. Here, we show SDHD-G12S and SDHD-H50R lead to impaired PTEN function through alteration of its subcellular localization accompanied by resistance to apoptosis and induction of migration in both papillary and follicular thyroid carcinoma cell lines. Other studies have shown elevated proto-oncogene tyrosine kinase (SRC) activity in invasive thyroid cancer cells; so, we explore bosutinib, a specific inhibitor for SRC, to explore SRC as a mediator of SDH-PTEN crosstalk in this context. We show that SRC inhibition could rescue SDHD dysfunction-induced cellular phenotype and tumorigenesis only when wild-type PTEN is expressed, in thyroid cancer lines. Patient lymphoblast cells carrying either SDHD-G12S or SDHD-H50R also show increased nuclear PTEN and more oxidized PTEN after hydrogen peroxide treatment. Like in thyroid cells, bosutinib decreases oxidative PTEN in patient lymphoblast cells carrying SDHD variants, but not in patients carrying both SDHD variants and PTEN truncating mutations. In summary, our data suggest a novel mechanism whereby SDHD germline variants SDHD-G12S or SDHD-H50R induce thyroid tumorigenesis mediated by PTEN accumulation in the nucleus and may shed light on potential treatment with SRC inhibitors like bosutinib in PTEN-wild-type SDHD-variant/mutation positive CS/CSL patients and sporadic thyroid neoplasias.