Characterization of metabolic reprogramming by metabolomics in the oncocytic thyroid cancer cell line XTC.UC1

Oncocytic thyroid cancer is characterized by the aberrant accumulation of abnormal mitochondria in the cytoplasm and a defect in oxidative phosphorylation. We performed metabolomics analysis to compare metabolic reprogramming among the oncocytic and non-oncocytic thyroid cancer cell lines XTC.UC1 and TPC1, respectively, and a normal thyroid cell line Nthy-ori 3-1. We found that although XTC.UC1 cells exhibit higher glucose uptake than TPC1 cells, the glycolytic intermediates are not only utilized to generate end-products of glycolysis, but also diverted to branching pathways such as lipid metabolism and the serine synthesis pathway. Glutamine is preferentially used to produce glutathione to reduce oxidative stress in XTC.UC1 cells, rather than to generate α-ketoglutarate for anaplerotic flux into the TCA cycle. Thus, growth, survival and redox homeostasis of XTC.UC1 cells rely more on both glucose and glutamine than do TPC1 cells. Furthermore, XTC.UC1 cells contained higher amounts of intracellular amino acids which is due to higher expression of the amino acid transporter ASCT2 and enhanced autophagy, thus providing the building blocks for macromolecules and energy production. These metabolic alterations are required for oncocytic cancer cells to compensate their defective mitochondrial function and to alleviate excess oxidative stress

Encapsulated Papillary Thyroid Tumor with Delicate Nuclear Changes and a Mutation as a Possible Novel Subtype of Borderline Tumor

Although papillary thyroid carcinoma (PTC)–type nuclear changes are the most reliable morphological feature in the diagnosis of PTC, the nuclear assessment used to identify these changes is highly subjective. Here, we report a noninvasive encapsulated thyroid tumor with a papillary growth pattern measuring 23 mm at its largest diameter with a nuclear score of 2 in a 26-year-old man. After undergoing left lobectomy, the patient was diagnosed with an encapsulated PTC. However, a second opinion consultation suggested an alternative diagnosis of follicular adenoma with papillary hyperplasia. When providing a third opinion, we identified a low MIB-1 labeling index and a heterozygous point mutation in the KRAS gene but not the BRAF gene. We speculated that this case is an example of a novel borderline tumor with a papillary structure. Introduction of the new terminology “noninvasive encapsulated papillary RAS-like thyroid tumor (NEPRAS)” without the word “cancer” might relieve the psychological burden of patients in a way similar to the phrase “noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP).

Studies on Expression of Aldehyde Dehydrogenase in Normal and Cancerous Tissues of Thyroids

Recently published articles have reported the controversial data regarding expression of aldehyde dehydrogenase isozyme 1A1 (ALDH1A1), a potential candidate marker for normal and cancer stem cells (CSCs), in thyroid tissues. These data prompted us to re-evaluate expression of ALDH1A1 in normal and cancerous thyroid tissues by 2 different means. The first method was immunohistochemistry with 2 different anti-ALDH1A1 antibodies from distinct companies. Following validating the integrity of these 2 antibodies by Western blotting with ALDH-expressing and nonexpressing cancer cell lines and immunohistochemistry with breast and colon tissues, we report here significant and comparable expression of ALDH1A1 in both normal and cancerous thyroid tissues with both antibodies. Next, relative expression levels of ALDH isozymes were evaluated by reverse transcription-polymerase chain reaction (RT-PCR), revealing that ALDH1A1 was the most highly expressed isozyme followed by ALDH9A1 and relative expression patterns of isozymes were very similar in normal and cancerous tissues. All these data demonstrate that thyroid cells of normal and cancer origins do express ALDH1A1 and to a lesser extent 9A1. Further study will be necessary to study functional significance of ALDH1A1 in the function and behaviors of thyroid normal and cancer stem cells

甲状腺刺激ホルモンシグナルは、BRAFV600E甲状腺癌マウスモデルにおけるゲノム不安定性を伴った高度悪性化に関与している

長崎大学学位論文 [学位記番号]博（医歯薬）甲第636号 [学位授与年月日]平成25年10月2

The FOXE1 and NKX2-1 loci are associated with susceptibility to papillary thyroid carcinoma in the Japanese population.

Background FOXE1 and NKX2-1 are two known genetic risk factors for the predisposition to sporadic papillary thyroid carcinoma (PTC) in Europeans, but their association in other ethnicities is still unknown. Objective We aim to examine the association of the two genes with Japanese sporadic PTC, which exhibits high BRAF(V600E) mutation rate. Methods 507 Japanese sporadic PTC cases and 2766 controls were genotyped for rs965513 (FOXE1) and rs944289 (NKX2-1). PTC cases were also examined for their BRAF(V600E) mutational status. Results The association of both rs965513 (p=1.27×10(-4), OR=1.69, 95% CI 1.29 to 2.21) and rs944289 (p=0.0121, OR=1.21, 95% CI 1.04 to 1.39) with the risk of sporadic PTC was confirmed. Subgroup analysis based on the BRAF mutational status showed strong association of rs965513 with BRAF(V600E)-positive cases (p=2.26×10(-4), OR=1.72, 95% CI 1.29 to 2.29), but not with BRAF(V600E)-negative cases (p=0.143, OR=1.52, 95% CI 0.87 to 2.65). However, there was no difference in the observed effect size between both subgroups. For rs944289, both subgroups showed marginal association (p=0.0585, OR=1.17, 95% CI 0.99 to 1.37 for BRAF(V600E)-positive cases; p=0.0492, OR=1.35, 95% CI 1.00 to 1.81 for BRAF(V600E)-negative cases). Conclusions Both FOXE1 and NKX2-1 were associated with the increased risk of sporadic Japanese PTC. No clear associations were observed for either SNP with BRAF(V600E) status

Identification of the first ATRIP-deficient patient and novel mutations in ATR define a clinical spectrum for ATR-ATRIP Seckel Syndrome

A homozygous mutational change in the Ataxia-Telangiectasia and RAD3 related (ATR) gene was previously reported in two related families displaying Seckel Syndrome (SS). Here, we provide the first identification of a Seckel Syndrome patient with mutations in ATRIP, the gene encoding ATR-Interacting Protein (ATRIP), the partner protein of ATR required for ATR stability and recruitment to the site of DNA damage. The patient has compound heterozygous mutations in ATRIP resulting in reduced ATRIP and ATR expression. A nonsense mutational change in one ATRIP allele results in a C-terminal truncated protein, which impairs ATR-ATRIP interaction; the other allele is abnormally spliced. We additionally describe two further unrelated patients native to the UK with the same novel, heterozygous mutations in ATR, which cause dramatically reduced ATR expression. All patient-derived cells showed defective DNA damage responses that can be attributed to impaired ATR-ATRIP function. Seckel Syndrome is characterised by microcephaly and growth delay, features also displayed by several related disorders including Majewski (microcephalic) osteodysplastic primordial dwarfism (MOPD) type II and Meier-Gorlin Syndrome (MGS). The identification of an ATRIP-deficient patient provides a novel genetic defect for Seckel Syndrome. Coupled with the identification of further ATR-deficient patients, our findings allow a spectrum of clinical features that can be ascribed to the ATR-ATRIP deficient sub-class of Seckel Syndrome. ATR-ATRIP patients are characterised by extremely severe microcephaly and growth delay, microtia (small ears), micrognathia (small and receding chin), and dental crowding. While aberrant bone development was mild in the original ATR-SS patient, some of the patients described here display skeletal abnormalities including, in one patient, small patellae, a feature characteristically observed in Meier-Gorlin Syndrome. Collectively, our analysis exposes an overlapping clinical manifestation between the disorders but allows an expanded spectrum of clinical features for ATR-ATRIP Seckel Syndrome to be define

Dedifferentiation of Human Primary Thyrocytes into Multilineage Progenitor Cells without Gene Introduction

While identification and isolation of adult stem cells have potentially important implications, recent reports regarding dedifferentiation/reprogramming from differentiated cells have provided another clue to gain insight into source of tissue stem/progenitor cells. In this study, we developed a novel culture system to obtain dedifferentiated progenitor cells from normal human thyroid tissues. After enzymatic digestion, primary thyrocytes, expressing thyroglobulin, vimentin and cytokeratin-18, were cultured in a serum-free medium called SAGM. Although the vast majority of cells died, a small proportion (∼0.5%) survived and proliferated. During initial cell expansion, thyroglobulin/cytokeratin-18 expression was gradually declined in the proliferating cells. Moreover, sorted cells expressing thyroid peroxidase gave rise to proliferating clones in SAGM. These data suggest that those cells are derived from thyroid follicular cells or at least thyroid-committed cells. The SAGM-grown cells did not express any thyroid-specific genes. However, after four-week incubation with FBS and TSH, cytokeratin-18, thyroglobulin, TSH receptor, PAX8 and TTF1 expressions re-emerged. Moreover, surprisingly, the cells were capable of differentiating into neuronal or adipogenic lineage depending on differentiating conditions. In summary, we have developed a novel system to generate multilineage progenitor cells from normal human thyroid tissues. This seems to be achieved by dedifferentiation of thyroid follicular cells. The presently described culture system may be useful for regenerative medicine, but the primary importance will be as a tool to elucidate the mechanisms of thyroid diseases

The Common Genetic Variant rs944289 on Chromosome 14q13.3 Associates with Risk of Both Malignant and Benign Thyroid Tumors in the Japanese Population

Background: Several single nucleotide polymorphisms (SNP) have been identified to be associated with the risk for differentiated thyroid cancer in populations of distinct ethnic background. The relationship of these genetic markers to a benign tumor of the thyroid, follicular adenoma (FA), is not well established. Methods: In a multicenter retrospective case-control study, five thyroid cancer-related SNPs - rs966513 (9q22.33, FOXE1), rs944289 (14q13.3, PTCSC3), rs2439302 (8p12, NRG1), rs1867277 (9q22.23, FOXE1), and rs6983267 (8q24, POU5F1B) - were genotyped in 959 cases of histologically verified FA, 535 papillary thyroid carcinomas (PTC), and 2766 population controls. Results: A significant association was found between FA and rs944289 (p=0.002; OR 1.176 [CI 1.064-1.316]), and suggestively with rs2439302 (p=0.033; OR 1.149 [CI 1.010-1.315]). In PTC, significant associations were confirmed for rs965513 (p=4.21E-04; OR 1.587 [CI 1.235-2.000]) and rs944289 (p=0.003; OR 1.234 [CI 1.075-1.408]), newly found for rs2439302 (p=0.003; OR 1.266 [CI 1.087-1.493]) and rs1867277 (p=1.17E-04; OR 1.492 [CI 1.235-1.818]), and was not replicated for rs6983267 (p=0.082; OR 1.136 [CI 0.980-1.316]) in this series. A significant correlation between rs2439302 genotype and relative expression of NRG1 was detected in normal and tumor counterparts of PTC (about 10% decrease per each risk allele). NRG1 expression also significantly correlated with that of PTCSC3. Conclusions: Association of rs944289, which was previously known to confer risk for thyroid cancer, with FA, and the correlation between PTCSC3 and NRG1 expression demonstrates that predisposing genetic factors are partly common for benign and malignant thyroid tumors, and imply broader roles of the pathways they underlie in thyroid tumorigenesis, not limited to carcinogenesis

Copy Number Alteration and Uniparental Disomy Analysis Categorizes Japanese Papillary Thyroid Carcinomas into Distinct Groups

The aim of the present study was to investigate chromosomal aberrations in sporadic Japanese papillary thyroid carcinomas (PTCs), concomitant with the analysis of oncogene mutational status. Twenty-five PTCs (11 with BRAFV600E, 4 with RET/PTC1, and 10 without mutation in HRAS, KRAS, NRAS, BRAF, RET/PTC1, or RET/PTC3) were analyzed using Genome-Wide Human SNP Array 6.0 which allows us to detect copy number alteration (CNA) and uniparental disomy (UPD), also referred to as copy neutral loss of heterozygosity, in a single experiment. The Japanese PTCs showed relatively stable karyotypes. Seven cases (28%) showed CNA(s), and 6 (24%) showed UPD(s). Interestingly, CNA and UPD were rarely overlapped in the same tumor; the only one advanced case showed both CNA and UPD with a highly complex karyotype. Thirteen (52%) showed neither CNA nor UPD. Regarding CNA, deletions tended to be more frequent than amplifications. The most frequent and recurrent region was the deletion in chromosome 22; however, it was found in only 4 cases (16%). The degree of genomic instability did not depend on the oncogene status. However, in oncogene-positive cases (BRAFV600E and RET/PTC1), tumors with CNA/UPD were less frequent (5/15, 33%), whereas tumors with CNA/UPD were more frequent in oncogene-negative cases (7/10, 70%), suggesting that chromosomal aberrations may play a role in the development of PTC, especially in oncogene-negative tumors. These data suggest that Japanese PTCs may be classified into three distinct groups: CNA+, UPD+, and no chromosomal aberrations. BRAFV600E mutational status did not correlate with any parameters of chromosomal defects

miR-196a Downregulation Increases the Expression of Type I and III Collagens in Keloid Fibroblasts

Keloids are a fibroproliferative disease due to abnormal wound healing process after skin injury. They are characterized by overproduction of extracellular matrix (ECM) such as collagens. MicroRNAs (miRNAs) are noncoding small RNAs and negatively regulate protein expression. Several miRNAs that have critical roles in tissue fibrosis and ECM metabolism have been reported. However, regulation and function of miRNAs in keloid remain to be explored. The purpose of this study was to identify miRNAs involved in keloid pathogenesis. We performed miRNA microarray analysis to compare miRNA expression profiles between keloid-derived fibroblasts (KFs) and normal fibroblasts (NFs). In all, 7 upregulated and 20 downregulated miRNAs were identified. Among these, we focused on miR-196a, which showed the highest fold change. Overexpression or knockdown of miR-196a led to a decreased or increased level of secreted type I/III collagens, respectively. Reporter analysis showed direct binding of miR-196a to the 3′ untranslated region (UTR) of COL1A1 and COL3A1. In conclusion, we demonstrate for the first time that miRNA expression profile is altered in KFs compared with NFs. Downregulation of miR-196a may be one of the mechanisms by which collagens are highly deposited in keloid tissues. Our findings suggest that miR-196a could be a new therapeutic target for keloid lesions