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PDF file - 138K, Table S1. Characteristics of 53 MTC (hereditary or sporadic) cases for which the RAS/MEK/ERK and PI3K/AKT/mTOR pathways were studied; Table S2. Study of MTC samples for RET and RAS mutation status and for immunoreactivity for pS6, pAKT and Perk; Table S3. Antibodies used for immunohistochemistry

Purpose: Understanding the molecular pathogenesis of medullary thyroid carcinoma (MTC) is prerequisite to the design of targeted therapies for patients with advanced disease.Experimental Design: We studied by immunohistochemistry the phosphorylation status of proteins of the RAS/MEK/ERK and PI3K/AKT/mTOR pathways in 53 MTC tissues (18 hereditary, 35 sporadic), including 51 primary MTCs and 2 cases with only lymph node metastases (LNM). We also studied 21 autologous LNMs, matched to 21 primary MTCs. Staining was graded on a 0 to 4 scale (S score) based on the percentage of positive cells. We also studied the functional relevance of the mTOR pathway by measuring cell viability, motility, and tumorigenicity upon mTOR chemical blockade.Results: Phosphorylation of ribosomal protein S6 (pS6), a downstream target of mTOR, was evident (S ≥ 1) in 49 (96%) of 51 primary MTC samples. This was associated with activation of AKT (phospho-Ser473, S > 1) in 79% of cases studied. Activation of pS6 was also observed (S ≥ 1) in 7 (70%) of 10 hereditary C-cell hyperplasia specimens, possibly representing an early stage of C-cell transformation. It is noteworthy that 22 (96%) of 23 LNMs had a high pS6 positivity (S ≥ 3), which was increased compared with autologous matched primary MTCs (P = 0.024). Chemical mTOR blockade blunted viability (P < 0.01), motility (P < 0.01), and tumorigenicity (P < 0.01) of human MTC cells.Conclusion: The AKT/mTOR pathway is activated in MTC, particularly, in LNMs. This pathway sustains malignant features of MTC cell models. These findings suggest that targeting mTOR might be efficacious in patients with advanced MTC. Clin Cancer Res; 18(13); 3532–40. ©2012 AACR.

PDF file - 87K, Figure S1: Both MZ-CRC-1 and TT MTC cells were treated with either rapamycin (rap; 50 nM, 24 hr), Rad001 (rad; 50 nM, 24 hr), vandetanib (vand;1,000 nM, 24 hr) or vehicle. Proteins were extracted and pS6 and pAKT phosphorylation measured by immunoblot in compound and mock treated cells. Total AKT and S6 were used for normalization

Supplementary Table 3 from A Cell Proliferation and Chromosomal Instability Signature in Anaplastic Thyroid Carcinoma

Supplementary Figure 1 from A Cell Proliferation and Chromosomal Instability Signature in Anaplastic Thyroid Carcinoma

Supplementary Table 4 from A Cell Proliferation and Chromosomal Instability Signature in Anaplastic Thyroid Carcinoma

Supplementary Table 5 from A Cell Proliferation and Chromosomal Instability Signature in Anaplastic Thyroid Carcinoma

Supplementary Methods from Identification of Polo-like Kinase 1 as a Potential Therapeutic Target in Anaplastic Thyroid Carcinoma

Supplementary Table 1 from A Cell Proliferation and Chromosomal Instability Signature in Anaplastic Thyroid Carcinoma

Supplementary Table 2 from A Cell Proliferation and Chromosomal Instability Signature in Anaplastic Thyroid Carcinoma

Supplementary Figure 1 from Identification of Polo-like Kinase 1 as a Potential Therapeutic Target in Anaplastic Thyroid Carcinoma

Here, we show that the anaplastic thyroid carcinoma (ATC) features the up-regulation of a set of genes involved in the control of cell cycle progression and chromosome segregation. This phenotype differentiates ATC from normal tissue and from well-differentiated papillary thyroid carcinoma. Transcriptional promoters of the ATC up-regulated genes are characterized by a modular organization featuring binding sites for E2F and NF-Y transcription factors and cell cycle–dependent element (CDE)/cell cycle gene homology region (CHR) cis-regulatory elements. Two protein kinases involved in cell cycle regulation, namely, Polo-like kinase 1 (PLK1) and T cell tyrosine kinase (TTK), are part of the gene set that is up-regulated in ATC. Adoptive overexpression of p53, p21 (CIP1/WAF1), and E2F4 down-regulated transcription from the PLK1 and TTK promoters in ATC cells, suggesting that these genes might be under the negative control of tumor suppressors of the p53 and pRB families. ATC, but not normal thyroid, cells depended on PLK1 for survival. RNAi-mediated PLK1 knockdown caused cell cycle arrest associated with 4N DNA content and massive mitotic cell death. Thus, thyroid cell anaplastic transformation is accompanied by the overexpression of a cell proliferation/genetic instability-related gene cluster that includes PLK1 kinase, which is a potential molecular target for ATC treatment. [Cancer Res 2007;67(21):10148–57]

Background Patients hospitalised for COVID-19 may present with or acquire bacterial or fungal infections that can affect the course of the disease. The aim of this study was to describe the microbiological characteristics of laboratory-confirmed infections in hospitalised patients with severe COVID-19. Methods We reviewed the hospital charts of a sample of patients deceased with COVID-19 from the Italian National COVID-19 Surveillance, who had laboratory-confirmed bacterial or fungal bloodstream infections (BSI) or lower respiratory tract infections (LRTI), evaluating the pathogens responsible for the infections and their antimicrobial susceptibility. Results Among 157 patients with infections hospitalised from February 2020 to April 2021, 28 (17.8%) had co-infections (≤ 48 h from admission) and 138 (87.9%) had secondary infections (> 48 h). Most infections were bacterial; LRTI were more frequent than BSI. The most common co-infection was pneumococcal LRTI. In secondary infections, Enterococci were the most frequently recovered pathogens in BSI (21.7% of patients), followed by Enterobacterales, mainly K. pneumoniae, while LRTI were mostly associated with Gram-negative bacteria, firstly Enterobacterales (27.4% of patients, K. pneumoniae 15.3%), followed by A. baumannii (19.1%). Fungal infections, both BSI and LRTI, were mostly due to C. albicans. Antibiotic resistance rates were extremely high in Gram-negative bacteria, with almost all A. baumannii isolates resistant to carbapenems (95.5%), and K. pneumoniae and P. aeruginosa showing carbapenem resistance rates of 59.5% and 34.6%, respectively. Conclusions In hospitalised patients with severe COVID-19, secondary infections are considerably more common than co-infections, and are mostly due to Gram-negative bacterial pathogens showing a very high rate of antibiotic resistance.

We have recently described Pz-1, a benzimidazole-based type-2 RET and VEGFR2 inhibitor. Based on a kinome scan, here we show that Pz-1 is also a potent (IC50 50 ~ 1 nM), with a negligible effect against RET- and TRKA-negative cells. By testing mutations, known to mediate resistance to other compounds, RET G810R/S, but not L730I/V, E732K, V738A and Y806N, showed some degree of resistance to Pz-1. In the case of TRKA, G595R and F589L, but not G667C, showed some degree of resistance. In xenograft models, orally administered Pz-1 almost completely inhibited RET- and TRKA-mutant tumours at 1–3 mg/kg/day but showed a reduced effect on RET/TRKA-negative cancer models. The activity, albeit reduced, on RET/TRKA-negative tumours may be justified by VEGFR2 inhibition. Tumours induced by NIH3T3 cells transfected by RET G810R and TRKA G595R featured resistance to Pz-1, demonstrating that RET or TRKA inhibition is critical for its anti-tumourigenic effect. In conclusion, Pz-1 represents a new powerful kinase inhibitor with distinct activity towards cancers induced by oncogenic RET and TRKA variants, including some mutants displaying resistance to other drugs.

Protection of early development contributes to health of next generations. Congenital anomalies (and other adverse reproductive outcomes) are an important public health issue and early indicator of public health risks, as early development is influenced by many risk factors (e.g., nutrition, lifestyles, pollution, infections, medications, etc). Effective primary prevention requires an integrated "One Health" approach, linking knowledge and action. This requires surveillance of health events and potential health-damaging factors, science-based risk analysis, citizens' empowerment and education of health professionals. From the policy standpoint, joint budgeting mechanisms are needed to sustain with equity intersectoral actions (involving policy domains of health, social affairs, education, agriculture and environment). States should devote resources to strengthen registries and systematic data collection for surveillance of congenital anomalies, to better inform national prevention strategies. Investing in primary prevention based on scientific evidence is essential to support sustainable and resilient health systems and sustainable development of the society.

Molecular differentiation between benign (follicular thyroid adenoma (FTA)) and malignant (follicular thyroid carcinoma (FTC)) thyroid neoplasms is challenging. Here, we explored the genome-wide DNA methylation profile of FTA (n.10) and FTC (n.11) compared to normal thyroid (NT) (n.7) tissues. FTC featured 3564 differentially methylated CpGs (DMCpG), most (84%) of them hypermethylated, with respect to normal controls. At the principal component analysis (PCA), the methylation profile of FTA occupied an intermediate position between FTC and normal tissue. A large fraction (n. 2385) of FTC-associated DMCpG was related (intragenic or within 1500 bp from the transcription start site) to annotated genes (n. 1786). FTC-hypermethylated genes were enriched for targets of the Polycomb transcriptional repressor complex and the specific histone H3 marks (H3K4me2/me3-H3K27me3) found in chromatin domains known as ‘bivalent’. Transcriptome profiling by RNAseq showed that 7.9% of the DMCpGs-associated genes were differentially expressed in FTC compared to NT, suggesting that altered DNA methylation may contribute to their altered expression. Overall, this study suggests that perturbed DNA methylation, in particular hypermethylation, is a component of the molecular mechanisms leading to the formation of FTC and that DNA methylation profiling may help differentiating FTCs from their benign counterpart.

MicroRNAs are a primordial mechanism of gene expression control that appear to be crucial to cellular development and may play an important role in tumor development. Much is known about the genetics of medullary thyroid carcinomas, as approximately 25% are hereditary and harbor germ line activating mutations in the RET gene. Somatic RET mutations are also seen in roughly 50% of sporadic medullary thyroid carcinomas. Few studies, however, have evaluated the role of microRNA expression in these tumors. DNA and RNA were extracted from formalin-fixed paraffin-embedded tissue blocks of 15 medullary thyroid carcinomas [10 with RET mutations (3 hereditary) and 5 without RET mutations] and 5 non-tumor thyroid glands. miRNA expression of 754 targets was quantitated by real time PCR using the ABI OpenArray miRNA assay. Three miRNAs showed significant differential expression and were validated in a larger cohort of 59 cases by real-time PCR. Expression of potential downstream targets and upstream regulators were also investigated by real-time PCR. miR-375 and miR-10a were significantly overexpressed, while miR-455 was underexpressed in medullary thyroid carcinomas. Expression of all 3 miRNAs were validated in the larger cohort of cases (miR-375, p = 3.3×10−26; miR-10a, p = 5.6×10−14; miR-455, p = 2.4×10−4). No significant differences in miRNA expression were found between RET mutation positive and negative tumors nor between sporadic and hereditary tumors. Expression of the potential downstream targets of miR-375, YAP1 (a growth inhibitor) and SLC16a2 (a transporter of thyroid hormone), was downregulated in the tumors suggesting that miR-375 is a negative regulator of the expression of these genes. Thus, differential expression of miR-375, miR-10a and miR-455 may be important for tumor development and/or the reflect c-cell lineage of medullary thyroid carcinoma. Furthermore, the growth inhibitor YAP1 is identified as a potential important downstream target of miR-375.

PMID:22919068.-- et al., Anaplastic thyroid carcinoma (ATC) is a very aggressive thyroid cancer. forkhead box protein M1 (FOXM1) is a member of the forkhead box family of transcription factors involved in control of cell proliferation, chromosomal stability, angiogenesis, and invasion. Here, we show that FOXM1 is significantly increased in ATCs compared with normal thyroid, well-differentiated thyroid carcinomas (papillary and/or follicular), and poorly differentiated thyroid carcinomas (P=0.000002). Upregulation of FOXM1 levels in ATC cells was mechanistically linked to loss-of-function of p53 and to the hyperactivation of the phosphatidylinositol-3-kinase/AKT/FOXO3a pathway. Knockdown of FOXM1 by RNA interference inhibited cell proliferation by arresting cells in G2/M and reduced cell invasion and motility. This phenotype was associated with decreased expression of FOXM1 target genes, like cyclin B1 (CCNB1), polo-like kinase 1 (PLK1), Aurora B (AURKB), S-phase kinase-associated protein 2 (SKP2), and plasminogen activator, urokinase: uPA (PLAU). Pharmacological inhibition of FOXM1 in an orthotopic mouse model of ATC reduced tumor burden and metastasization. All together, these findings suggest that FOXM1 represents an important player in thyroid cancer progression to the anaplastic phenotype and a potential therapeutic target for this fatal cancer., This study was supported by the Associazione Italiana per la Ricerca sul Cancro (AIRC), the Ministero dell'Università e della Ricerca (MiUR), and by the grant MERIT of MIUR. G Garcia-Rostan is supported by Programa Ramón y Cajal, Ministerio de Ciencia e Innovación, Social EU Funds, Universidad de Valladolid, Spain. C Nucera (Principal Investigator, Program: Human Thyroid Cancers Preclinical and Translational Research) was funded by the NIHR21CA165039-01A1 and the American Thyroid Association for Thyroid Cancer Research.

For an identification of novel candidate genes in thyroid tumourigenesis, we have investigated gene copy number changes in aTrk-T1transgenic mouse model of thyroid neoplasia. For this aim, 30 thyroid tumours fromTrk-T1transgenics were investigated by comparative genomic hybridisation. Recurrent gene copy number alterations were identified and genes located in the altered chromosomal regions were analysed by Gene Ontology term enrichment analysis in order to reveal gene functions potentially associated with thyroid tumourigenesis. In thyroid neoplasms fromTrk-T1mice, a recurrent gain on chromosomal bands 1C4–E2.3 (10.0% of cases), and losses on 3H1–H3 (13.3%), 4D2.3–E2 (43.3%) and 14E4–E5 (6.7%) were identified. The genesTwist2,Ptma,Pde6d,Bmpr1b,Pdlim5,Unc5c,Srm,Trp73,Ythdf2,Taf12andSlitrk5are located in these chromosomal bands. Copy number changes of these genes were studied by fluorescencein situhybridisation on 30 human papillary thyroid carcinoma (PTC) samples and altered gene expression was studied by qRT-PCR analyses in 67 human PTC. Copy number gains were detected in 83% of cases forTWIST2and in 100% of cases forPTMAandPDE6D. DNA losses ofSLITRK1andSLITRK5were observed in 21% of cases and ofSLITRK6in 16% of cases. Gene expression was significantly up-regulated forUNC5CandTP73and significantly down-regulated forSLITRK5in tumours compared with normal tissue. In conclusion, a global genomic copy number analysis of thyroid tumours fromTrk-T1transgenic mice revealed a number of novel gene alterations in thyroid tumourigenesis that are also prevalent in human PTCs.

The objective of the study was to explore high-frequency ultrasound (HFUS) for noninvasive microimaging of thyroid in living mice. Thyroid examination was performed by HFUS in 10 normal C57BL/6 mice, eight mice treated by propylthiouracil, and 22 Tg-TRK-T1 transgenic mice. The dimension of the gland and the presence of nodules were evaluated. Nodules were classified as malignant (hypoechogenicity, poorly defined margins, internal microcalcification, irregular shapes, and extra glandular extension) or not, and the findings were compared with histological data. Thyroid images were successfully obtained in all the animals analyzed. Normal thyroid reached a volume of 4.92 microl (range 2.11-4.92 microl). Mice with propylthiouracil-induced goiter showed diffuse thyroid enlargement (median volume 6.67 microl, range 4.09-8.82 microl). In 19 of 22 Tg-TRK-T1 mice (86%), HFUS identified a nodular process (the smallest detected nodule had a diameter of 0.46 mm). Eleven nodules were classified as malignant and eight as benign. Compared with histological analysis, HFUS showed a sensitivity of 100% in the detection of thyroid nodules and a specificity of 60% (two of the nodules identified by HFUS were not confirmed at the histology). The specificity and sensitivity of HFUS in predicting the malignancy of the thyroid nodules were 83 and 91%, respectively. Thus, HFUS is an accurate imaging modality that can potentially replace more invasive techniques, and, therefore, it represents a significant advancement in phenotypic assessment of mouse models of thyroid cancer.

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive and chemoresistant cancers. The serine/threonine kinase Polo-like kinase 1 (PLK1), a key regulator of multiple steps during mitotic progression, is highly expressed in ATC. Here, we used the BI 2536 PLK1 inhibitor on ATC and nontransformed thyroid follicular cell lines. Our data show that ATC cells are addicted to high levels of PLK1 activity for proliferation, survival, anchorage-independent growth, and tumorigenicity. On treatment with nanomolar doses of BI 2536, ATC cells progressed normally through S phase but died thereafter, directly from mitotic arrest. Immunofluorescence microscopy, immunoblot, and flow cytometry analysis showed that, on PLK1 blockade, ATC cells arrested in prometaphase with a 4N DNA content. Treated ATC cells accumulated phosphohistone H3 and displayed characteristic mitotic (Polo) spindle aberrations. Nontransformed thyroid cells were 3.2- to 18.4-fold less susceptible to BI 2536–induced cell cycle effects compared with ATC cells. These findings identify PLK1 as a promising target for the molecular therapy of ATC. [Cancer Res 2009;69(5):1916–23]

Here we describe a conditional doxycycline-dependent mouse model of RET/PTC3 (NCOA4-RET) oncogene-induced thyroid tumorigenesis. In these mice, after 10 days of doxycycline (dox) administration, RET/PTC3 expression induced mitogen activated protein kinase (MAPK) stimulation and a proliferative response which resulted in the formation of hyperplastic thyroid lesions. This was followed, after 2 months, by growth arrest accompanied by typical features of oncogene-induced senescence (OIS), including upregulation of p16INK4A and p21CIP, positivity at the Sudan black B, activation of the DNA damage response (DDR) markers γH2AX and pChk2 T68, and induction of p53 and p19ARF. After 5 months, about half of thyroid lesions escaped OIS and formed tumors that remained dependent on RET/ PTC3 expression. This progression was accompanied by activation of AKT-FOXO1/3a pathway and increased serum TSH levels.

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive human tumors. Twist1 is a basic helix-loop-helix transcription factor involved in cancer development and progression. We showed that Twist1 affects thyroid cancer cell survival and motility.We aimed to identify Twist1 targets in thyroid cancer cells.Transcriptional targets of Twist1 were identified by gene expression profiling the TPC-Twist1 cells in comparison with control cells. Functional studies were performed by silencing in TPC-Twist1 and in CAL62 cells the top 10 upregulated genes and by evaluating cell proliferation, survival, migration, and invasion. Chromatin immunoprecipitation was performed to verify direct binding of Twist1 to target genes. Quantitative RT-PCR was applied to study the expression level of Twist1 target genes in human thyroid carcinoma samples.According to the gene expression profile, the top functions enriched in TPC-Twist1 cells were cellular movement, cellular growth and proliferation, and cell death and survival. Silencing of the top 10 upregulated genes reduced viability of TPC-Twist1 and of CAL62 cells. Silencing of COL1A1, KRT7, and PDZK1 also induced cell death. Silencing of HS6ST2, THRB, ID4, RHOB, and PDZK1IP also impaired migration and invasion of TPC-Twist1 and of CAL62 cells. Chromatin immunoprecipitation showed that Twist1 directly binds the promoter of the top 10 upregulated genes. Quantitative RT-PCR showed that HS6ST2, COL1A1, F2RL1, LEPREL1, PDZK1, and PDZK1IP1 are overexpressed in thyroid carcinoma samples compared with normal thyroids.We identified a set of genes that mediates Twist1 biological effects in thyroid cancer cells.

et al., CD97, a member of the adhesion family of G-protein-coupled receptors (GPCRs), complexes with and potentiates lysophosphatidic acid (LPA) receptor signaling to the downstream effector RHOA. We show here that CD97 was expressed in a majority of thyroid cancers but not normal thyroid epithelium and that the level of CD97 expression was further elevated with progression to poorly differentiated and undifferentiated carcinoma. Intratumoral progression also showed that CD97 expression correlates with invasiveness and dedifferentiation. To determine the functional role of CD97, we produced a transgenic model of thyroglobulin promoter-driven CD97 expression. Transgenic CD97 in combination with Thrb(PV), an established mouse model of thyroid follicular cell carcinogenesis, significantly increased the occurrence of vascular invasion and lung metastasis. Expression of transgenic CD97 in thyroid epithelium led to elevated ERK phosphorylation and increased numbers of Ki67+ cells in developing tumors. In addition, tumor cell cultures derived from CD97 transgenic as compared with non-transgenic mice demonstrated enhanced, constitutive and LPA-stimulated ERK activation. In human thyroid cancer cell lines, CD97 depletion reduced RHO-GTP and decreased LPA-stimulated invasion but not EGF-stimulated invasion, further suggesting that CD97 influences an LPA-associated mechanism of progression. Consistent with the above, CD97 expression in human thyroid cancers correlated with LPA receptor and markers of aggressiveness including Ki67 and pAKT. This study shows an autonomous effect of CD97 on thyroid cancer progression and supports the investigation of this GPCR as a therapeutic target for these cancers., This work was supported by the Intramural Research Program, Center for Cancer Research, National Cancer Institute and the Programa Ramón y Cajal—Ministerio de Ciencia e Innovación, Social EU Funds, Universidad de Valladolid, Spain.

10 páginas, 5 figuras, 1 tabla.-- et al., [Context]:Anaplastic thyroid carcinoma (ATC) is one of the most aggressive human tumors; it is characterized by chemoresistance, local invasion, and distant metastases. ATC is invariably fatal. [Objective]:The aim was to study the role of TWIST1, a basic helix-loop-helix transcription factor, in ATC. [Design]:Expression of TWIST1 was studied by immunohistochemistry and real-time PCR in normal thyroids and well-differentiated, poorly differentiated, and ATC. The function of TWIST1 was studied by RNA interference in ATC cells and by ectopic expression in well-differentiated thyroid carcinoma cells. [Results]:ATCs up-regulate TWIST1 with respect to normal thyroids as well as to poorly and well-differentiated thyroid carcinomas. Knockdown of TWIST1 by RNA interference in ATC cells reduced cell migration and invasion and increased sensitivity to apoptosis. The ectopic expression of TWIST1 in thyroid cells induced resistance to apoptosis and increased cell migration and invasion. [Conclusions]:TWIST1 plays a key role in determining malignant features of the anaplastic phenotype in vitro., This work was supported by the Associazione Italiana per la Ricerca sul Cancro, the Istituto Superiore di Oncologia, the Italian Ministero della Salute, the Ministero dell’Università e della Ricerca, the European Community Contract FP6-36495, and the Programa Ramón y Cajal–Ministerio de Ciencia e Innovación, Social EU Funds, Universidad de Valladolid, Spain.

Reactive oxygen species, specifically hydrogen peroxide (H2O2), have a significant role in hormone production in thyroid tissue. Although recent studies have demonstrated that dual oxidases are responsible for the H2O2 synthesis needed in thyroid hormone production, our data suggest a pivotal role for superoxide dismutase 3 (SOD3) as a major H2O2-producing enzyme. According to our results, Sod3 is highly expressed in normal thyroid, and becomes even more abundant in rat goiter models. We showed TSH-stimulated expression of Sod3 via phospholipase C–Ca2+ and cAMP–protein kinase A, a pathway that might be disrupted in thyroid cancer. In line with this finding, we demonstrated an oncogene-dependent decrease in Sod3 mRNA expression synthesis in thyroid cancer cell models that corresponded to a similar decrease in clinical patient samples, suggesting that SOD3 could be used as a differentiation marker in thyroid cancer. Finally, the functional analysis in thyroid models indicated a moderate role for SOD3 in regulating normal thyroid cell proliferation being in line with our previous observations.

Context: The V600E mutation accounts for the vast majority of thyroid carcinoma-associated BRAF mutations. Objective: The aim was to study the effects of the two BRAF V600E ATP-competitive kinase inhibitors, PLX4032 and PLX4720, in thyroid carcinoma cell lines. Experimental Design: We examined the activity of PLX4032 and PLX4720 in thyroid carcinoma cell lines harboring BRAF V600E (8505C, BCPAP, SW1736, BHT101), NRAS Q61R (HTH7), KRAS G12R (CAL62), HRAS G13R (C643), or RET/PTC1 (TPC-1) oncogenes. Normal thyrocytes (PC Cl 3) were used as control. Results: Both compounds inhibited the proliferation of BRAF mutant cell lines, but not normal thyrocytes, with a half maximal effective concentration (EC50) ranging from 78-113 nM for PLX4720 and from 29-97 nM for PLX4032. Doses equal to or higher than 500 nM were required to achieve a similar effect in BRAF wild-type cancer cells. Phosphorylation of ERK 1/2 and MAPK kinase (MEK) 1/2 decreased upon PLX4032 and PLX4720 treatment in BRAF mutant thyroid carcinoma cells but not in normal thyroid cells or in cell lines harboring mutations of RAS or RET/PTC1 rearrangements. PLX4032 and PLX4720 treatment induced a G1 block and altered expression of genes involved in the control of G1-S cell-cycle transition. 8505C cell tumor xenografts were smaller in nude mice treated with PLX4032 than in control mice. This inhibition was associated with reduction of phospho-ERK and phospho-MEK levels. Conclusions: This study provides additional evidence of the promising nature of mutant BRAF as a molecular target for thyroid carcinoma cells.

Purpose: Oncogenic conversion of BRAF occurs in ∼44% of papillary thyroid carcinomas and 24% of anaplastic thyroid carcinomas. In papillary thyroid carcinomas, this mutation is associated with an unfavorable clinicopathologic outcome. Our aim was to exploit BRAF as a potential therapeutic target for thyroid carcinoma. Experimental Design: We used RNA interference to evaluate the effect of BRAF knockdown in the human anaplastic thyroid carcinoma cell lines FRO and ARO carrying the BRAF V600E (V600EBRAF) mutation. We also exploited the effect of BAY 43-9006 [N-(3-trifluoromethyl-4-chlorophenyl)-N'-(4-(2-methylcarbamoyl pyridin-4-yl)oxyphenyl)urea], a multikinase inhibitor able to inhibit RAF family kinases in a panel of six V600EBRAF-positive thyroid carcinoma cell lines and in nude mice bearing ARO cell xenografts. Statistical tests were two sided. Results: Knockdown of BRAF by small inhibitory duplex RNA, but not control small inhibitory duplex RNA, inhibited the mitogen-activated protein kinase signaling cascade and the growth of ARO and FRO cells (P < 0.0001). These effects were mimicked by thyroid carcinoma cell treatment with BAY 43-9006 (IC50 = 0.5-1 μmol/L; P < 0.0001), whereas the compound had negligible effects in normal thyrocytes. ARO cell tumor xenografts were significantly (P < 0.0001) smaller in nude mice treated with BAY 43-9006 than in control mice. This inhibition was associated with suppression of phospho–mitogen-activated protein kinase levels. Conclusions: BRAF provides signals crucial for proliferation of thyroid carcinoma cells spontaneously harboring the V600EBRAF mutation and, therefore, BRAF suppression might have therapeutic potential in V600EBRAF-positive thyroid cancer.

Background Through a transcriptome microarray analysis, we have isolated Anterior gradient protein 2 (AGR2) as a gene up-regulated in papillary thyroid carcinoma (PTC). AGR2 is a disulfide isomerase over-expressed in several human carcinomas and recently linked to endoplasmic reticulum (ER) stress. Here, we analyzed the expression of AGR2 in PTC and its functional role. Methods Expression of AGR2 was studied by immunohistochemistry and real time PCR in normal thyroids and in PTC samples. The function of AGR2 was studied by knockdown in PTC cells and by ectopic expression in non-transformed thyroid cells. The role of AGR2 in the ER stress was analyzed upon treatment of cells, expressing or not AGR2, with Bortezomib and analyzing by Western blot the expression levels of GADD153. Results PTC over-expressed AGR2 at mRNA and protein levels. Knockdown of AGR2 in PTC cells induced apoptosis and decreased migration and invasion. Ectopic expression of AGR2 in non-transformed human thyroid cells increased migration and invasion and protected cells from ER stress induced by Bortezomib. Conclusions AGR2 is a novel marker of PTC and plays a role in thyroid cancer cell survival, migration, invasion and protection from ER stress.

The Republic of San Marino, a small, 23-square mile, independent country near the Adriatic Coast within Italy, has been noted to have a high incidence of gastric cancer in its 22,000 population (9% of atl deaths from 1969-1983 with 33% of all cancer deaths attributed to gastric cancer). Gastroscopic biopsy studies on 284 first degree relatives of San Marinese gastric cancer patients in the Republic of San Marino and in Detroit, where 2,000-2,500 San Marinese reside, have allowed detection of six gastric malignancies. Intestinal metaplasia of gastric mucosa was found in 16 (52%) of 31 Detroit first degree relatives and 51 (36%) of 143 San Marino first degree relatives. Gastroscopy provides an important tool not only for the early detection of gastric cancer in populations of high risk (such as that of San Marino), but also for providing clues to the genetic and environmental factors in gastric neoplasia.

Purpose: Understanding the molecular pathogenesis of medullary thyroid carcinoma (MTC) is prerequisite to the design of targeted therapies for patients with advanced disease. Experimental Design: We studied by immunohistochemistry the phosphorylation status of proteins of the RAS/MEK/ERK and PI3K/AKT/mTOR pathways in 53 MTC tissues (18 hereditary, 35 sporadic), including 51 primary MTCs and 2 cases with only lymph node metastases (LNM). We also studied 21 autologous LNMs, matched to 21 primary MTCs. Staining was graded on a 0 to 4 scale (S score) based on the percentage of positive cells. We also studied the functional relevance of the mTOR pathway by measuring cell viability, motility, and tumorigenicity upon mTOR chemical blockade. Results: Phosphorylation of ribosomal protein S6 (pS6), a downstream target of mTOR, was evident (S ≥ 1) in 49 (96%) of 51 primary MTC samples. This was associated with activation of AKT (phospho-Ser473, S > 1) in 79% of cases studied. Activation of pS6 was also observed (S ≥ 1) in 7 (70%) of 10 hereditary C-cell hyperplasia specimens, possibly representing an early stage of C-cell transformation. It is noteworthy that 22 (96%) of 23 LNMs had a high pS6 positivity (S ≥ 3), which was increased compared with autologous matched primary MTCs (P = 0.024). Chemical mTOR blockade blunted viability (P < 0.01), motility (P < 0.01), and tumorigenicity (P < 0.01) of human MTC cells. Conclusion: The AKT/mTOR pathway is activated in MTC, particularly, in LNMs. This pathway sustains malignant features of MTC cell models. These findings suggest that targeting mTOR might be efficacious in patients with advanced MTC. Clin Cancer Res; 18(13); 3532–40. ©2012 AACR.