Expression of cancer stem cell markers is more frequent in anaplastic thyroid carcinoma compared to papillary thyroid carcinoma and is related to adverse clinical outcome

Glomangiosarcoma-like Anaplastic Transformation in Papillary Thyroid Carcinoma: A Novel Form of Heterologous Differentiation and a Systematic Review of Heterologous Element Prevalence

Anaplastic thyroid carcinoma (ATC) demonstrates a wide variety of morphologies and is characteristically associated with a differentiated thyroid carcinoma component. Heterologous differentiation is a rare, potentially challenging phenomenon in ATC, mostly observed as osteosarcomatous or chondrosarcomatous differentiation. We now describe a novel 'glomangiosarcoma-like' differentiation, review our archival experience from two institutions (UPMC, CC), and perform a systematic review for the prevalence of heterologous elements in ATC. The patient is a 57-year-old female who presented with 4.5 cm left thyroid, and 3.4 cm neck masses. Histologically, the thyroid demonstrated a differentiated high grade papillary thyroid carcinoma, tall cell and hobnail/micropapillary subtypes transitioning into an anaplastic component with spindled to ovoid cells with hemangiopericytoma-like vasculature showing CD34 positivity, variable muscle marker expression and pericellular lace-like type IV collagen deposition. The neck mass consisted solely of the latter morphology. Targeted next-generation sequencing was performed on high grade DTC and adjacent ATC from the thyroid as well as ATC from the neck metastasis. All three components shared BRAFV600E, TERT promoter, and PIK3CA mutations confirming a clonal origin. Archival (UPMC: n = 150, CC: n = 74) and literature review showed no prior examples. Systematic review and meta-analysis of prevalence showed a baseline pooled prevalence (generalized linear mixed model) of heterologous elements of any type to be 1.6% (95% confidence interval: 1.0-2.6%) for studies where this was specifically addressed. ATC with glomangiosarcoma-like heterologous differentiation is a rarity among an already rare morphologic category with unique diagnostic pitfalls.

SOX4 is a pivotal regulator of tumorigenesis in differentiated thyroid cancer

The SOX family consists of about 20 transcription factors involved in embryonic development, reprogramming, and cell fate determination. In this study, we demonstrated that SOX4 was significantly upregulated in differentiated thyroid cancer. Immunohistochemical analysis revealed that high SOX4 expression was associated with papillary histology, extrathyroidal extension, lymph node metastasis, and advanced disease stage. Patients whose tumors exhibited high SOX4 expression had a shorter recurrence-free survival, though significance was lost in multivariate Cox regression analysis. SOX4 silencing in thyroid cancer cells slowed cell growth, attenuated clonogenicity, and suppressed anoikis resistance. Additionally, SOX4 knockdown impeded xenograft tumor growth in nude mice. Knockdown of SOX4 expression was accompanied by reduced phosphorylation of AKT and ERK. Furthermore, CRABP2 expression correlated with SOX4 expression, and SOX4 silencing decreased CRABP2 expression and its downstream effectors such as integrin β1 and β4. These results indicate that SOX4 has both prognostic and therapeutic implications in differentiated thyroid cancer, and targeting SOX4 may modulate tumorigenic processes in the thyroid.

Long non-coding ROR promotes the progression of papillary thyroid carcinoma through regulation of the TESC/ALDH1A1/TUBB3/PTEN axis

Papillary thyroidal carcinoma (PTC) is a common endocrine cancer that plagues people across the world. The potential roles of long non-coding RNAs (lncRNAs) in PTC have gained increasing attention. In this study, we aimed to explore whether lncRNA ROR affects the progression of PTC, with the involvement of tescalcin (TESC)/aldehyde dehydrogenase isoform 1A1 (ALDH1A1)/βIII-tubulin (TUBB3)/tensin homolog (PTEN) axis. PTC tumor and adjacent tissues were obtained, followed by measurement of lncRNA ROR and TESC, ALDH1A1, and TUBB3 expression. Interactions among lncRNA ROR, TESC, ALDH1A1, TUBB3, and PTEN were evaluated by ChIP assay, RT-qPCR, or western blot analysis. After ectopic expression and depletion experiments in PTC cells, MTT and colony formation assay, Transwell assay, and flow cytometry were performed to detect cell viability and colony formation, cell migration and invasion, and apoptosis, respectively. In addition, xenograft in nude mice was performed to test the effects of lncRNA ROR and PTEN on tumor growth in PTC in vivo. LncRNA ROR, TESC, ALDH1A1, and TUBB3 were highly expressed in PTC tissues and cells. Overexpression of lncRNA ROR activated TESC by inhibiting the G9a recruitment on the promoter of TESC and histone H3-lysine 9me methylation. Moreover, TESC upregulated ALDH1A1 expression to increase TUBB3 expression, which then reduced PTEN expression. Overexpression of lncRNA ROR, TESC, ALDH1A1 or TUBB3 and silencing of PTEN promoted PTC cell viability, colony formation, migration, and invasion while suppressing apoptosis. Moreover, overexpression of lncRNA ROR increased tumor growth by inhibiting PTEN in vivo. Taken together, the current study demonstrated that lncRNA ROR mediated TESC/ALDH1A1/TUBB3/PTEN axis, thereby facilitating the development of PTC.

Capsaicin inhibits the stemness of anaplastic thyroid carcinoma cells by triggering autophagy-lysosome mediated OCT4A degradation

Capsaicin (CAP) is a well-known anti-cancer agent. Recently, we reported capsaicin-induced apoptosis in anaplastic thyroid cancer (ATC) cells. It is well accepted that the generation of cancer stem cells (CSCs) is responsible for the dedifferentiation of ATC, the most lethal subtype of thyroid cancer with highly dedifferentiation status. Whether CAP inhibited the ATC growth through targeting CSCs needed further investigation. In the present study, CAP was found to induce autophagy in ATC cells through TRPV1 activation and subsequent calcium influx. Meanwhile, CAP dose-dependently decreased the sphere formation capacity of ATC cells. The stemness-inhibitory effect of CAP was further by extreme limiting dilution analysis (ELDA). CAP significantly decreased the protein level of OCT4A in both 8505C and FRO cells. Furthermore, CAP-induced OCT4A degradation was reversed by autophagy inhibitors 3-MA and chloroquine, BAPTA-AM and capsazepine, but not proteasome inhibitor MG132. Collectively, our study firstly showed CAP suppressed the stemness of ATC cells partially via calcium-dependent autophagic degradation of OCT4A. Our study lent credence to the feasible application of capsaicin in limiting ATC stemness.

Expression of cancer stem cell markers in tall cell variant papillary thyroid cancer identifies a molecular profile predictive of recurrence in classic papillary thyroid cancer

BACKGROUND

Tall cell variant of papillary thyroid carcinoma is an aggressive subtype of papillary thyroid carcinoma. We examined expression of cancer stem cell markers in tall cell variant compared with other well-differentiated thyroid cancers.

METHODS

Expression of cancer stem cell markers was examined in 572 thyroid tumors from The Cancer Genome Atlas Thyroid Cancer database and tall cell variant and papillary thyroid carcinoma tumors by immunohistochemistry.

RESULTS

Expression of the PROM1 gene, encoding the cancer stem cell marker CD133, was elevated in tall cell variant compared to classic papillary thyroid carcinoma in a large cohort of unmatched samples from The Cancer Genome Atlas Thyroid Cancer database (P < .001). By immunohistochemistry in age and stage matched samples, CD133 protein was confirmed to be significantly increased in tall cell variant versus classic papillary thyroid carcinoma (P = .006). Analyzing all thyroid cancers, high PROM1 expression was associated with worse disease-specific survival. Optimal cutoffs were determined to define a tall cell variant-like cancer stem cell signature characterized by high PROM1, high ALDH1A3, and low CD24 expression. Classic papillary thyroid carcinoma with a tall cell variant-like gene signature had worse recurrence disease-free survival compared to classic papillary thyroid carcinoma with a non-tall cell variant signature (P = .02).

CONCLUSION

Tall cell variant of papillary thyroid carcinoma has increased expression of cancer stem cell markers compared to classic papillary thyroid carcinoma. The tall cell variant-like cancer stem cell gene signature identified a molecular subtype of classic papillary thyroid carcinoma that has a worse recurrence-free survival.

Study on the Antitumor Effect and Glycolysis of Andrographolide in Anaplastic Thyroid Carcinoma

OBJECTIVE

To investigate the antitumor effect of andrographolide on the ATC cell lines 8505C and CAL62 and to explore the possible mechanism of the effect.

METHODS

CCK8 and colony formation assays were performed to detect proliferation. Cell migration was tested by scratch assay. Annexin V/PI staining was used to detect cell apoptosis and cell cycle. Glucose and lactic acid kits were carried out to evaluate the glycolysis level after andrographolide treatment. Western blot was used to detect the changes in the apoptosis-related proteins and glycolysis-related enzymes in both 8505C and CAL62 cells.

RESULTS

Treatment with 60 μM andrographolide had significant effects on 8505C and CAL62, including inhibition of proliferation, inhibition of migration, arrest of the cell cycle, promotion of apoptosis, and inhibition of glycolysis.

CONCLUSION

Andrographolide has an antitumor effect and can significantly affect glycolysis in ATC cells.

The Role of Snail-1 in Thyroid Cancer-What We Know So Far

Thyroid carcinomas, despite the usually indolent behaviour and relatively good overall prognosis, show a high tendency to gain invasive phenotype and metastasise in some cases. However, due to a relatively slow progression, the exact mechanisms governing the metastatic process of thyroid carcinomas, including the epithelial-to-mesenchymal transition (EMT), are poorly described. One of the best-known regulators of cancer invasiveness is Snail-1-a zinc-finger transcription factor that plays a key role as an EMT inducer. More and more attention is being paid to the role of Snail with regard to thyroid cancer development. Apart from the obvious implications in the EMT process, Snail-1 plays an important role in the regulation of chemoresistance of the thyroid cells and cancer stem cell (CSC) formation, and it also interacts with miRNA specific to the thyroid gland. The aim of this review was to summarise the knowledge on Snail-1, especially in the context of thyroid oncogenesis.

Small bowel perforation and death caused by anaplastic thyroid carcinoma metastasis in a patient with concomitant colonic and bilateral breast carcinoma

Undifferentiated or anaplastic thyroid carcinoma (ATC) is rare and one of the most aggressive human malignancies. The tumor is usually voluminous and fast-growing and mostly affects older women. The most common sites of distant metastases are the lungs, brain, and bones. Herein, we describe the case of a 66-year-old woman with a history of bilateral breast carcinoma and ATC, who presented with an acute abdomen and subsequently died. At autopsy, an isolated metastasis of ATC in the small intestine leading to bowel perforation was found. Moreover, there was adenocarcinoma in the descending colon. The review of extra-abdominal malignancies metastasizing to bowel and coincidence of breast and thyroid carcinoma is included.

Diallyl trisulphide, a H2 S donor, compromises the stem cell phenotype and restores thyroid-specific gene expression in anaplastic thyroid carcinoma cells by targeting AKT-SOX2 axis

It is widely accepted that anaplastic thyroid carcinoma (ATC), a rare, extremely aggressive malignant, is enriched by cancer stem cells (CSCs), which are closely related to the pathogenesis of ATC. In the present study, we demonstrated that diallyl trisulphide (DATS), a well-known hydrogen sulphide (H₂ S) donor, suppressed sphere formation and restored the expression of iodide-metabolizing genes in human ATC cells, which were associated with H₂ S generation. Two other H₂ S donors, NaHS and GYY4137, could also suppress the self-renewal properties of ATC cells in vitro. Compared with normal thyroid tissues and papillary thyroid carcinomas (PTCs), the elevated expressions of SOX2 and MYC, two cancer stem cell markers, in ATCs were validated in the combined Gene Expression Omnibus (GEO) cohort. DATS decreased the expression of SOX2, which was mediated by H₂ S generation. Furthermore, knockdown of AKT or inhibition of AKT by DATS led to a decrease of SOX2 expression in ATC cells. AKT knockdown phenocopied restoration of thyroid-specific gene expression in ATC cells. Our data suggest that H₂ S donors treatment can compromise the stem cell phenotype and restore thyroid-specific gene expression of ATC cells by targeting AKT-SOX2 pathway, which may serve as a therapeutic strategy to intervene the CSC progression of ATC.

Thyroid Carcinoma: Phenotypic Features, Underlying Biology and Potential Relevance for Targeting Therapy

Thyroid carcinoma consists a group of phenotypically heterogeneous cancers. Recent advances in biological technologies have been advancing the delineation of genetic, epigenetic, and non-genetic factors that contribute to the heterogeneities of these cancers. In this review article, we discuss new findings that are greatly improving the understanding of thyroid cancer biology and facilitating the identification of novel targets for therapeutic intervention. We review the phenotypic features of different subtypes of thyroid cancers and their underlying biology. We discuss recent discoveries in thyroid cancer heterogeneities and the critical mechanisms contributing to the heterogeneity with emphases on genetic and epigenetic factors, cancer stemness traits, and tumor microenvironments. We also discuss the potential relevance of the intratumor heterogeneity in understanding therapeutic resistance and how new findings in tumor biology can facilitate designing novel targeting therapies for thyroid cancer.

Solid variant of papillary thyroid carcinoma: an under-recognized entity

Solid variant of papillary thyroid carcinoma (SVPTC) is a rare morphological variant of papillary thyroid carcinoma (PTC). SVPTC is histologically characterized by predominant solid, trabecular and insular nests of tumor cells while cytological features of PTC such as nuclear grooves and nuclear inclusions are preserved. In fine needle aspiration cytology smears, tumor cells of SVPTC may be presented in cohesive, syncytial or trabecular clusters accompanied by some discohesiveness in the absence of necrosis. Although SVPTC and poorly differentiated thyroid carcinoma (PDTC) share similar histological findings of solid nests, SVPTC can be differentiated from PDTC in the lack of tumor necrosis, severe nuclear atypia, and a higher mitotic index. Immunohistochemical expression of CK19 and HBME-1, common markers of PTC, is decreased in solid nests of SVPTC. In pediatric patients exposed to radiation after the Chernobyl nuclear accident, there was a higher prevalence of SVPTC with RET/PTC3 type rearrangement. BRAF mutations are also reported in a small number of adult patients with SVPTC without any prior radiation exposure. Patients with SVPTC may have a slightly higher incidence of metastasis and recurrence of the tumor compared to conventional PTC, although overall survival rate is comparable. In this article, the current knowledge of SVPTC will be reviewed and discussed with an emphasis on the histopathological feature.

Clinical Significance of Cancer Stem Cell Markers CD133 and CXCR4 in Osteosarcomas

Objective:

Osteosarcomas (OS) is one the most common primary bone malignancy in humans with the lungs metastasis in most cases. Metastasis and recurrence of OS is attributed to cancer stem cells (CSCs). Our study aimed to evaluate the clinical significance of CD133 and C-X-C chemokine receptor type 4 (CXCR4) as the frequently applied markers for CSCs in OS patients.

Methods:

In this cross-sectional, a total of 50 tissue samples from the patients with primary OS were immunohistochemically examined to detect the expression of CD133 and CXCR4. The associations of the relative expression and clinical significance of each marker were also evaluated.

Results:

High level expression of CD133 was detected in 26% of OS patient tissues. Of the 12 patients who showed lung metastasis, 5 cases showed high expression of CD133 with marginal trend correlation (P=0.06). No significant correlation was observed between CD133 expression and clinicopathological factors. Only 36% of cases showed CXCR4 expression which was not significantly correlated with gender, age, tumor size, necrosis, stage and metastasis (P>0.05). Clinically, patients with concomitant CD133/CXCR4 expression had significant association with lung metastasis (P=0.05).

Conclusion:

Our findings showed that concomitant expression of CSC markers CD133/CXCR4 might had a synergistic effect on the OS poor prognosis. These markers could be considered as potential therapeutic candidates of OS targeted therapy.

The Role of ATP-Binding Cassette Transporters in the Chemoresistance of Anaplastic Thyroid Cancer: A Systematic Review

Anaplastic thyroid cancer (ATC) is an aggressive type of thyroid cancer with a high mortality rate. Cytotoxic drugs are among the treatment modalities usually used for ATC treatment. However, systemic chemotherapies for ATC have not been shown to have remarkable efficacy. ATP-binding cassette (ABC) transporters have been suggested as a possible mechanism in ATC resistance to chemotherapy. This systematic review was aimed to define the possible roles of ABC transporters in ATC resistance to chemotherapy. Numerous databases, including Scopus, Web of Science, PubMed, Cochrane Library, Ovid, ProQuest, and EBSCO, were searched for papers published since 1990, with predefined keywords. The literature searches were updated twice, in 2015 and 2017. All identified articles were reviewed, and 14 papers that met the inclusion criteria were selected. In the eligible studies, the roles of 10 out of 49 ABC transporters were evaluated; among them, three pumps (ABCB1, ABCC1, and ABCG2) were the most studied transporters in ATC samples. ABCC1 and ABCG2 had the highest expression rates in ATC, and ABCB1 ranked second among the inspected transporters. In conclusion, ABC transporters are the major determinants of ATC resistance to chemotherapy. By identifying these transporters, we can tailor the best treatment approach for patients with ATC. Additional studies are needed to define the exact role of each ABC transporter and other mechanisms in ATC drug resistance.

Combined effects of octreotide and cisplatin on the proliferation of side population cells from anaplastic thyroid cancer cell lines

Anaplastic thyroid cancer (ATC) represents the most aggressive subtype of thyroid cancer and has a poor prognosis. In addition to surgery, chemotherapy is an important treatment for ATC; however, the therapeutic effects of current chemotherapies for ATC are not particularly promising. There is a high proportion of side population (SP) cells in ATC, which may be a reason for its drug resistance. In the present study, the antitumor activities of combined octreotide (OCT) and cisplatin (DDP) on the proliferation and apoptosis of ATC SP cells were evaluated. First, SP cells from 8305C and BHT101 cell lines were detected and sorted. Following in vitro culture for 1 week, cluster of differentiation (CD)44, CD133, ATP-binding cassette (ABC) subfamily B member 1 (ABCB1), ABC subfamily G member 2 (ABCG2) and somatostatin receptor expression was detected to characterize the SP cells. An MTT assay was performed to investigate the combined effects on 8305C-SP cell proliferation in vitro, and a mouse model was used to investigate the combined effects on 8305C-SP cell proliferation in vivo. Annexin V/propidium iodide staining was used to investigate the combined effects on 8305C-SP cell apoptosis. Chemotherapeutic drug resistance-associated protein expression and apoptosis-associated protein expression were also detected following combined treatment. As a result, SP cells were identified in 8305C and BHT101 cells, and the proportion of 8305C-SP cells was increased compared with that of BTH101-SP cells. SP cells have enhanced proliferation, tumorigenicity and drug resistance compared with main population cells. The combined treatment of OCT with DDP suppressed the proliferation of 8305C-SP cells in vitro and in vivo, and induced 8305C-SP cell apoptosis. Combined treatment decreased the ABCB1 and ABCG2 expression by SP cells and activated mitochondrial apoptotic signaling, resulting in cell apoptosis. In conclusion, these data support the hypothesis that combined treatment with OCT and DDP induces ATC cell apoptosis and suppresses cell proliferation. These data provide a theoretical basis for further combined chemotherapy clinical applications.

Role of transmembrane glycoprotein mucin 1 (MUC1) in various types of colorectal cancer and therapies: Current research status and updates

Colorectal carcinoma (CRC) is the third most common malignant tumor in the world. In recent years, the morbidity and mortality of CRC have increased in the world due to increasingly ageing population, modern dietary habits, environmental change, genetic disorders and chronic intestinal inflammation. Despite recent advances in earlier detection and improvements in chemotherapy, the 5-year survival rate of patients with metastatic CRC remains low. Therefore, novel effective treatment strategies for primary or metastatic CRC have emerged to enhance cure rate as well as elongation of patient's survival. Immunotherapy has been proposed for a potentially effective therapeutic approach to the treatment of CRC. Tumor vaccination in preclinical and clinical studies has supported the antitumor activity induced by immunization with CRC cell vaccines. Epithelial cell molecule Mucin 1 (MUC1), a transmembrane glycoprotein aberrantly overexpressed in various cancers including CRC, has been used as a candidate target antigen in the peptide, dendritic cell, and whole tumor vaccines. Several clinical trials in progress reveal the immunogenicity and suitability of MUC1 that acted as immunotherapeutic vaccines for CRC/colorectal cancer stem cells (CCSC). The present review summarizes the potential roles of MUC1 on CRC/CCSC vaccines according to the latest data. Moreover, this review also discusses the novel strategies for targeting CCSC via inducing an immune response against MUC1 to achieve the best prevention and treatment effects in animal models and clinical trails.

Loss of One or Two PATZ1 Alleles Has a Critical Role in the Progression of Thyroid Carcinomas Induced by the RET/PTC1 Oncogene

POZ/BTB and AT-hook-containing zinc finger protein 1 (PATZ1) is an emerging cancer-related gene that is downregulated in different human malignancies, including thyroid cancer, where its levels gradually decrease going from papillary thyroid carcinomas (PTC) to poorly differentiated and undifferentiated highly aggressive anaplastic carcinomas (ATC). The restoration of PATZ1 expression in thyroid cancer cells reverted their malignant phenotype by inducing mesenchymal-to-epithelial transition, thus validating a tumor suppressor role for PATZ1 and suggesting its involvement in thyroid cancer progression. Here, we investigated the consequences of the homozygous and heterozygous loss of PATZ1 in the context of a mouse modeling of PTC, represented by mice carrying the RET/PTC1 oncogene under the thyroid specific control of the thyroglobulin promoter RET/PTC1 (RET/PTC1^TG). The phenotypic analysis of RET/PTC1^TG mice intercrossed with Patz1-knockout mice revealed that deficiency of both Patz1 alleles enhanced thyroid cancer incidence in RET/PTC1^TG mice, but not the heterozygous knockout of the Patz1 gene. However, both RET/PTC1^TG;Patz1^+/− and RET/PTC1^TG;Patz1^−/− mice developed a more aggressive thyroid cancer phenotype—characterized by higher Ki-67 expression, presence of ATCs, and increased incidence of solid variants of PTC—than that shown by RET/PTC1^TG; Patz1^+/+ compound mice. These results confirm that PATZ1 downregulation has a critical role in thyroid carcinogenesis, showing that it cooperates with RET/PTC1 in thyroid cancer progression.

Multicellular spheroids from normal and neoplastic thyroid tissues as a suitable model to test the effects of multikinase inhibitors

Multicellular three-dimensional (3D) spheroids represent an experimental model that is intermediate in its complexity between monolayer cultures and patients’ tumor. In the present study, we characterize multicellular spheroids from papillary (PTC) and follicular (FTC) thyroid cancers and from the corresponding normal tissues. We show that these 3D structures well recapitulate the features of the original tissues, in either the differentiated and “stem-like” components. As a second step, we were aimed to test the effects of a small multikinase inhibitor, SP600125 (SP), previously shown to efficiently induce cell death in undifferentiated thyroid cancer monolayer cultures. We demonstrate the potent effect of SP on cell growth and survival in our 3D multicellular cultures. SP exerts its main effects through direct and highly significant inhibition of the ROCK pathway, known to be involved in the regulation of cell migration and β-catenin turnover. Consistently, SP treatment resulted in a significant decrease in β-catenin levels with respect to basal conditions in tumor but not in normal spheroids, indicating that the effect is promisingly selective on tumor cells.

In conclusion, we provide the morphological and molecular characterization of thyroid normal and tumor spheroids. In this 3D model we tested in vitro the effects of the multikinase inhibitor SP and further characterized its mechanism of action in both normal and tumor spheroids, thus making it an ideal candidate for developing new drugs against thyroid cancer.

Interleukin-11 promotes epithelial-mesenchymal transition in anaplastic thyroid carcinoma cells through PI3K/Akt/GSK3β signaling pathway activation

Metastasis is the major cause of treatment failure in anaplastic thyroid carcinoma (ATC) patients. In the preliminary study, we demonstrated that interleukin (IL)-11 expression is positively correlated with distant metastasis in ATC. However, the mechanisms underlying remain largely unknown. Here, we found that cobalt chloride (a hypoxia mimetic) promoted IL-11 expression via HIF-1α activation. Furthermore, the resultant increase in IL-11 expression significantly induced epithelial-mesenchymal transition (EMT) in ATC cells, accompanied by Akt/GSK3β pathway activation and increased invasive and migratory abilities. Conversely, HIF-1α or IL-11 knockdown, or treating cells with a neutralizing antibody against IL-11, a PI3K inhibitor, or Akt inhibitor V, significantly suppressed the induction of EMT and counteracted the enhancements in invasive and migratory abilities. These results indicate that hypoxia increases IL-11 secretion in ATC cells via HIF-1α induction and that IL-11 then induces EMT in these cells via the PI3K/Akt/GSK3β pathway, ultimately improving their invasive and migratory potential. This study elucidates the prometastatic role played by IL-11 in ATC metastasis and indicates it as a potential target for the treatment of cancer metastasis. However, many questions remain to be explored.

Upregulated SOX9 expression indicates worse prognosis in solid tumors: a systematic review and meta-analysis

It was recently reported that increased SOX9 expression drives tumor growth and promotes cancer invasion during human tumorigenicity and metastasis. However, the prognostic value of SOX9 for the survival of patients with solid tumors remains controversial. The present meta-analysis was thus performed to highlight the link between dysregulated SOX9 expression and prognosis in cancer patients. A systematic literature search was conducted using the electronic databases PubMed, Web of Science and Embase to identify eligible studies. A random-effects meta-analytical model was employed to correlate SOX9 expression with overall survival (OS), disease-free survival (DFS) and clinicopathological features. In total, 17 studies with 3307 patients were eligible for the final analysis. Combined hazard ratios (HRs) and 95% confidence intervals (CIs) suggested that high SOX9 expression has an unfavourable impact on OS (HR = 1.66, 95% CI 1.36-2.02, P < 0.001) and DFS (HR = 3.54, 95% CI 2.29-5.47, P = 0.008) in multivariate analysis. Additionally, the pooled odds ratios (ORs) indicated that SOX9 over-expression is associated with large tumor size, lymph node metastasis, distant metastasis and a higher clinical stage. Overall, these results indicated that SOX9 over-expression in patients with solid tumors might be related to poor prognosis and could serve as a potential predictive marker of poor clinicopathological prognosis factor.

Thyrospheres from B-CPAP Cell Line with BRAF and TERT Promoter Mutations have Different Functional and Molecular Features than Parental Cells

Human thyroid cancer derived cell lines are widely used to study the mechanisms involved in thyroid carcinogenesis. However, there is limited availability of non-cross-contaminated cancer cell lines derived from papillary thyroid carcinoma (PTC), and the B-CPAP cell line is one of the few such lines. B-CPAP cells have been genetically and cytogenetically well-characterized, but details of their stemness features remain uncertain. Considering that this cell line is extensively used for in vitro studies on thyroid tumorigenesis, we broaden its functional and molecular profiles as well as the tumorigenic capacity. We used functional assays (sphere-forming capacity and efficiency), assessed self-renewal and propagation efficiency and tested in vivo tumorigenicity in Hsd:Athymic Nude-Foxn1^nu mice. Expression of markers of stemness, differentiation, and epithelial-mesenchymal transition were estimated at RNA and protein levels in adherent parental cells and sphere-forming cells. Functional aspects and stemness features were compared with normal thyrocytes. Protein expression of xenograft tumors was evaluated by immunohistochemistry. B-CPAP sphere-forming cells were able to form thyrospheres theoretically indefinitely in an appropriate serum-free medium, reverting to the adherent parental cell phenotype when cultured in differentiation medium. Different expression of ALDH1-A1 and CD44 stemness markers and TTF-1 and CK19 differentiation markers allowed discrimination between isolated sphere-forming cells and adherent parental cells, indicating that sphere-forming cells retained stem-like features. In keeping with these observations, tumorigenicity assays confirmed that, relative to parental adherent cells, thyrospheres had enhanced capacity to initiate xenograft tumors. Thyrospheres from normal cell line retained very low functional capacity, as well as different stemness markers expression compared to tumor thyrospheres. Our findings may constitute a useful background to develop an in vitro model for assessing the origin and progression of papillary thyroid carcinoma bearing BRAF^V600E and TERT promoter mutations.

Emerging roles of the CXCL12/CXCR4 axis in pancreatic cancer progression and therapy

Chemokine networks regulate a variety of cellular, physiological, and immune processes. These normal functions can become appropriated by cancer cells to facilitate a more hospitable niche for aberrant cells by enhancing growth, proliferation, and metastasis. This is especially true in pancreatic cancer, where chemokine signaling is a vital component in the development of the supportive tumor microenvironment and the signaling between the cancer cells and surrounding stromal cells. Although expression patterns vary among cancer types, the chemokine receptor CXCR4 has been implicated in nearly every major malignancy and plays a prominent role in pancreatic cancer development and progression. This receptor, in conjunction with its primary chemokine ligand CXCL12, promotes pancreatic cancer development, invasion, and metastasis through the management of the tumor microenvironment via complex crosstalk with other pathways. Thus, CXCR4 likely contributes to the poor prognoses observed in patients afflicted with this malignancy. Recent exploration of combination therapies with CXCR4 antagonists have demonstrated improved outcomes, and abolishing the contribution of this pathway may prove crucial to effectively treat pancreatic cancer at both the primary tumor and metastases.

Prognostic value of putative cancer stem cell markers (CD24, CD44, CD133, and ALDH1) in human papillary thyroid carcinoma

We hypothesized that cancer stem cells (CSCs) are responsible for the poor outcome and aggressive clinicopathological factors. We surveyed the expression of selected CSC markers that are specifically expressed in thyroid papillary carcinoma (PTC). A total of 80 patients with PTC from 2011 to 2012 were enrolled. We selected CD24, CD44, CD133, and dehydrogenase 1 (ALDH1), as they have been suggested to be candidate CSC markers. Expression of these markers was investigated by immunohistochemical (IHC) staining. IHC staining for CD24, CD44, CD133 and ALDH1 was evaluated according to staining intensity and proportion. The intensity and proportion scores were multiplied together for a total score, which was either 0-2 (negative) or 3-7 (positive). IHC for CD133 in PTC was positive in 49 (61.3%) patients, and CD24 was positive in 28 (35.0%). Seventy-eight (97.5%) patients were CD44 positive and 79 (98.8%) were ALDH1 positive. When we assessed the relationship between CSC markers and clinicopathological factors in PTC, CD24 expression was inversely correlated with multifocality (p=0.045; odds ratio [OR], 0.370; 95% confidence interval [CI], 0.138-0.991) and CD44 expression was significantly correlated with a BRAF mutation (p=0.001; OR, 7.091; 95% CI, 4.101-12.262). However, CD133 and ALDH1 were not associated with any of the clinicopathological parameters. CD24 expression was inversely correlated with multifocality, and CD44 expression was significantly correlated with a BRAF mutation. Therefore, CD24 and CD44 are related to clinicopathological aggressive features and important for determining surgical extent in patients with PTC.

Expression of MRP1 and ABCG2 is associated with adverse clinical outcomes of papillary thyroid carcinoma with a solid component

Solid variant of papillary thyroid carcinoma (PTC) is characterized by a solid component (SC) retaining classical cytological features of PTC. Despite some controversies, PTC with SC (PTCSC) cases have poor prognosis compared with well-differentiated PTC. We investigated if cancer stem cells (CSCs) may have a role in pathogenesis of PTCSC. PTCSC tumors (n=27) were histologically represented by a mixture of papillary component (PC) and varying degrees of SC involving 10% to 85% of the tumor. Immunohistochemical expression of CSC markers ABCG2 and MRP1, and HBME1 and CK19 was compared between SC and PC within each tumor in association with clinicopathological parameters. ABCG2 and MRP1 were highly expressed in SC, whereas their expression was limited or absent in PC (P=.04 and .002, respectively). In contrast, expression of HBME1 and CK19 appeared higher in PC than in SC (P=.08 and .02, respectively). Higher expression of ABCG2 was associated with higher incidence of large-sized SC (P=.01). Higher expression of MRP1 was associated with higher incidence of lymphovascular invasion (P=.049). Higher expression of ABCG2 and MRP1, and lower expression of CK19 in SC were associated with higher tumor recurrence rate (P=.02, .01, and .02, respectively), and shorter disease-free survival (P<.001 for all the variables). Our findings indicate that the tumor cells harboring CSC-like characteristics in SC could contribute to the pathogenesis of PTCSC and might account for the poor disease prognosis.

Cancer stem-like cell behavior in anaplastic thyroid cancer: A challenging dilemma

AIMS

Anaplastic thyroid carcinoma (ATC) is an undifferentiated tumor of the thyroid which is characterized with poor prognosis, leading to its aggressive behavior and resistance to conventional therapies. Cancer stem cells (CSCs) are tumor cells that have self-renewal and clonal tumor initiation. Like other cancers, many studies have shown that ATC also has tumor cells with properties like stem cells. To evaluate the concept of cancer stem-like cell theory of ATC, we conducted this study to emphasize both on the concept of cancer stemness origin of these cells and target them for further therapeutic purposes. In the current study, we showed that two ATC cell lines, SW1736 and C643, have subpopulations (SP) that are similar to CSCs.

MATERIALS AND METHODS

Using MACS technique, cells positive for CD133 were isolated and subsequently validated with flow cytometry. For further analysis, expression of some stemness markers was evaluated.

KEY FINDINGS

ABCG2, CD133, and Sox2 were significantly up-regulated, while Nestin was down-regulated in CD133(pos) subpopulation compared to CD133(neg) cells. In contrast to previous reports that over-expression of Nestin was considered as a marker for thyroid CSCs, we noticed that expression of Nestin was declined in stem cell-like tumor cells, derived from ATC cell lines.

SIGNIFICANCE

This study reconfirmed the concept of cancer stem-like cell identity of SW1736 and C643 cells. Indeed, the characterization of CSCs should not be merely based on surface markers. Cell origin and genetic background should be additionally considered on CSCs subpopulation of ATCs for therapeutics.

Expression of CD133 in differentiated thyroid cancer of young patients

AIMS

CD133 expression in cancer is frequently associated with poor outcome. Thyroid carcinomas are rare in childhood and adolescence and are associated with a higher risk of recurrence and more metastases than the adult tumours. The aim of the study was to assess whether the expression of CD133 in thyroid carcinomas of children, adolescents and young adults was correlated with clinical prognostic factors.

METHODS

Tissue microarrays were constructed with 235 tumours coming from 208 young adults with a median age of 28 years and 27 children with a median age of 13 years. An immunohistochemical study was performed with anti-CD133 antibody. CD133 expression was evaluated, using a semiquantitative score based on the percentage of positive cells. The mutation status of tumours was evaluated by reverse transcriptase PCR. Three cell lines were used to confirm CD133 expression by western blot.

RESULTS

CD133 expression was found in 43% of adult and 37% of child tumours and was confirmed by western blot in cell lines. In young adults, the expression of CD133 was significantly more frequent in patients with tumours >3 cm (p=0.04) and in patients with lymph node metastases (p=0.02). The expression of CD133 was more frequent in patients in whom the tumour presented a BRAF mutation (p=0.03).

CONCLUSIONS

CD133 expression is correlated with tumour size, lymph nodes metastases and BRAF mutations in young adults. The presence of these cancer stem cells could offer new therapeutic alternatives for aggressive thyroid cancers.

Development and characterization of six new human papillary thyroid carcinoma cell lines

CONTEXT

Cell lines are a widely used tool in cancer research. However, despite the relatively high incidence of papillary thyroid carcinoma (PTC), there are only four PTC cell lines available for international research audience.

OBJECTIVE

The objective of this study was to establish and characterize new PTC cell lines that represent primary tumor biology. Surgical specimens were obtained to generate PTC cell lines. Short tandem repeat profiling was used to confirm the uniqueness of the cell lines against databases of known cell lines and mutations were assessed using Sequenom. The expression of thyroid-specific genes was examined using real-time PCR. Tumorigenicity was determined using an orthotopic thyroid xenograft tumor mouse model.

RESULTS

Six PTC cell lines (five conventional PTCs and one follicular variant of PTC) were generated and found to be unique when compared by short tandem repeat profiling against databases of all existing cell lines. The five conventional PTC cell lines carry the BRAF V600E mutation and the follicular variant of PTC cell line had an NRAS mutation. Five of the six cell lines had a mutation in the promoter of the human telomerase reverse transcriptase gene. None of the cell lines have RET/PTC rearrangements. Three cell lines were tumorigenic in the orthotopic thyroid xenograft tumor mouse model.

CONCLUSIONS

These five characterized conventional PTC cell lines and the unique follicular variant of PTC cell line should be valuable reagents for thyroid cancer research. The three tumorigenic cell lines can be used for in vivo testing of targeted therapeutic and novel agents.

Anaplastic Thyroid Carcinoma: A ceRNA Analysis Pointed to a Crosstalk between SOX2, TP53, and microRNA Biogenesis

It has been suggested that cancer stem cells (CSC) may play a central role in oncogenesis, especially in undifferentiated tumours. Anaplastic thyroid carcinoma (ATC) has characteristics suggestive of a tumour enriched in CSC. Previous studies suggested that the stem cell factor SOX2 has a preeminent hierarchical role in determining the characteristics of stem cells in SW1736 ATC cell line. In detail, silencing SOX2 in SW1736 is able to suppress the expression of the stem markers analysed, strongly sensitizing the line to treatment with chemotherapeutic agents. Therefore, in order to further investigate the role of SOX2 in ATC, a competing endogenous RNA (ceRNA) analysis was conducted in order to isolate new functional partners of SOX2. Among the interactors, of particular interest are genes involved in the biogenesis of miRNAs (DICER1, RNASEN, and EIF2C2), in the control cell cycle (TP53, CCND1), and in mitochondrial activity (COX8A). The data suggest that stemness, microRNA biogenesis and functions, p53 regulatory network, cyclin D1, and cell cycle control, together with mitochondrial activity, might be coregulated.

Immunohistochemical Diagnosis of Thyroid Tumors

Recent insight into the molecular mechanisms of thyroid carcinogenesis has led to studies involving newly directed antibodies. With the introduction of new molecular targeted therapies, these antibodies may represent useful predictors of therapeutic response in tumors unresponsive to radioiodine or insensitive to conventional antitumor therapies. These markers complement the development of markers that are able to discern benign from malignant entities, including hyalinizing trabecular tumors, oncocytic neoplasms, and follicular variant of papillary thyroid carcinoma. The use of antibodies directed to proteins generated by mutated genes may represent a cost-effective method for diagnosing and managing patients affected by thyroid tumors.

Mechanisms of therapeutic resistance in cancer (stem) cells with emphasis on thyroid cancer cells

The two main reasons for death of cancer patients, tumor recurrence and metastasis, are multi-stage cellular processes that involve increased cell plasticity and coincide with elevated resistance to anti-cancer treatments. Epithelial-to-mesenchymal transition (EMT) is a key contributor to metastasis in many cancer types, including thyroid cancer and is known to confer stem cell-like properties onto cancer cells. This review provides an overview of molecular mechanisms and factors known to contribute to cancer cell plasticity and capable of enhancing cancer cell resistance to radio- and chemotherapy. We elucidate the role of DNA repair mechanisms in contributing to therapeutic resistance, with a special emphasis on thyroid cancer. Next, we explore the emerging roles of autophagy and damage-associated molecular pattern responses in EMT and chemoresistance in tumor cells. Finally, we demonstrate how cancer cells, including thyroid cancer cells, can highjack the oncofetal nucleoprotein high-mobility group A2 to gain increased transformative cell plasticity, prevent apoptosis, and enhance metastasis of chemoresistant tumor cells.

Thyroid tumor-initiating cells: increasing evidence and opportunities for anticancer therapy (review)

Accumulating evidence supports the notion that thyroid cancer is initiated by tumor-initiating cells (TICs) (commonly known as cancer stem cells), which are thought to play a crucial role in malignant progression, therapeutic resistance and recurrence. Thyroid TICs have been isolated and identified using specific biomarkers (such as CD133), the side population, sphere formation and aldehyde dehydrogenase activity assays. Although their characteristics remain largely unknown, TICs provide an attractive cellular mechanism to explain therapeutic refractoriness. Efforts are currently being directed toward the identification of therapeutic strategies that could target these cells. The present review discusses the cellular origins of TICs and the main approaches used to isolate and identify thyroid TICs, with a focus on the remaining challenges and opportunities for anticancer therapy.