Upregulation of HMGA2 in thyroid carcinomas: a novel molecular marker to distinguish between benign and malignant follicular neoplasias

Assessing the potential of high-mobility group AT-hook 2 immunohistochemical staining as a prognostic marker of metastatic recurrence in follicular thyroid cancer: a retrospective cohort study

High-mobility group AT-hook 2 (HMGA2) is a nuclear protein involved in the differentiation and proliferation of epithelial-derived tumors and also considered to be involved in the growth and differentiation of various malignant tumors, including thyroid cancer. Immunohistochemistry (IHC) for HMGA2 has been reported to show diffuse positivity in several follicular thyroid carcinoma (FTC) cases. This study aimed to investigate whether positive immunohistochemical staining for HMGA2 in primary tumors can be used to predict the prognosis and detect prognostic factors in malignant thyroid tumors associated with metastatic recurrence in FTC. Formalin-fixed, paraffin-embedded (FFPE) resected specimens used for the IHC for HMGA2. The association of positive HMGA2 staining with metastasis and recurrence, along with the potential of HMGA2 as a prognostic marker of metastatic recurrence, was statistically determined. HMGA2 staining was positive in most malignant tissues, whereas benign tissues were unstained. HMGA2 staining of the marginal and invasive regions was observed in FTC tissues. The association of HMGA2 staining with metastasis and recurrence was significant (p = 0.018). Kaplan-Meier curves showed an association of negative HMGA2 staining with metastasis and disease-free survival (p = 0.090). Tumor size (>4 cm) and wide invasion were also significant factors (p = 0.043, p < 0.001). The risk ratio without HMGA2 was significantly reduced by 30% compared to that with HMGA2. In primary tumors, positive HMGA2 staining can be used to predict prognosis in malignant thyroid tumors associated with metastatic recurrence in FTC and negative HMGA2 staining may indicate longer disease-free survival after surgery.

Goistrat: gene-of-interest-based sample stratification for the evaluation of functional differences

PURPOSE

Understanding the impact of gene expression in pathological processes, such as carcinogenesis, is crucial for understanding the biology of cancer and advancing personalised medicine. Yet, current methods lack biologically-informed-omics approaches to stratify cancer patients effectively, limiting our ability to dissect the underlying molecular mechanisms.

RESULTS

To address this gap, we present a novel workflow for the stratification and further analysis of multi-omics samples with matched RNA-Seq data that relies on MSigDB curated gene sets, graph machine learning and ensemble clustering. We compared the performance of our workflow in the top 8 TCGA datasets and showed its clear superiority in separating samples for the study of biological differences. We also applied our workflow to analyse nearly a thousand prostate cancer samples, focusing on the varying expression of the FOLH1 gene, and identified specific pathways such as the PI3K-AKT-mTOR gene sets as well as signatures linked to prostate tumour aggressiveness.

CONCLUSION

Our comprehensive approach provides a novel tool to identify disease-relevant functions of genes of interest (GOI) in large datasets. This integrated approach offers a valuable framework for understanding the role of the expression variation of a GOI in complex diseases and for informing on targeted therapeutic strategies.

HMGA2 Overexpression in Papillary Thyroid Cancer Promotes Thyroid Cell Dedifferentiation and Invasion, and These Effects Are Counteracted by Suramin

Thyroid cancer is the most prevalent endocrine malignancy, and papillary thyroid carcinoma (PTC) is the most common type of thyroid malignancy. While PTC generally has a favorable prognosis, a subset dedifferentiates into aggressive forms. However, the molecular mechanisms responsible for aggressiveness and dedifferentiation are still poorly understood. We previously showed that HMGA2, a non-histone architectural transcription factor overexpressed in PTC, is involved in cell invasion. This study aimed to further analyze the role of HMGA2 in PTC tumorigenesis by exploring the expression of thyroid-specific and EMT-related genes following HMGA2 knockdown in thyroid cancer cell lines. Then, the clinical relevance of our data was evaluated in vivo. HMGA2 silencing did not modulate the expression of EMT related genes but led to the increased expression of thyroid differentiation genes. Our data also suggest that the MAPK pathway induces thyroid cell dedifferentiation through HMGA2. On the other hand, forskolin, promoting thyroid differentiation, decreased HMGA2 expression. The negative correlations between HMGA2 and thyroid-specific gene expressions were confirmed in a transgenic mouse model of PTC and in human PTC. Finally, we showed that HMGA2 inhibition by suramin reduced cell invasion and induced differentiation expression in vitro, indicating a new therapeutic strategy for treating thyroid cancer.

Effects of HMGA2 on the biological characteristics and stemness acquisition of gastric cancer cells

BACKGROUND AND STUDY AIMS

The high mobility group A2 (HMGA2), a nonhistone nuclear binding protein, modulates transcription by altering the chromatin architecture of the target gene DNA in its specific AT-hooks region. HMGA2 overexpression has been observed in embryonic tissue and many malignant neoplasms. This study sought to verify whether HMGA2 plays a role in the biological functions of gastric cancer cells, such as cell proliferation, invasiveness, migration, and stem cell acquisition, and to provide some ideas for further research on the metastatic mechanism of gastric cancer.

PATIENTS AND METHODS

HMGA2's effects on the proliferation, invasiveness, and migration capabilities of gastric cancer cells were individually detected by BrdU, Transwell, and wound healing assays. Western blotting and immunofluorescence were used to evaluate whether HMGA2 could promote the acquisition of gastric cancer cells. Biostatistical analyses were performed using SPSS 17.0 for Windows.

RESULTS

HMGA2 expression levels in gastric cancer cell lines were significantly higher than those in human immortalized gastric epithelial cell lines (p < 0.01). Gastric cancer cell proliferation was inhibited when HMGA2 was overexpressed (p < 0.05). The invasiveness and migration capabilities of gastric cancer cells with HMGA2 overexpression were enhanced more than those of the corresponding control groups (p < 0.05). HMGA2 overexpression promotes the stemness acquisition of stem cells from gastric cancer cells.

CONCLUSIONS

This study verified that the HMGA2 structural transcription factor promotes invasiveness, migration, and acquisition of gastric cancer cells. Furthermore, our findings provide significant insight for further research on the metastatic mechanism of gastric cancer.

LINC02454 promotes thyroid carcinoma progression via upregulating HMGA2 through CREB1

Thyroid carcinoma (THCA) is the most common malignancy in the endocrine system. Long intergenic non-coding RNA 2454 (LINC02454) exhibits an HMGA2-like expression pattern, but their relationship and roles in THCA are largely unknown. The present purpose was to delineate the roles of LINC02454 in THCA progression and its molecular mechanisms. We collected THCA tissues from patients and monitored patient survival. THCA cell colony formation, migration, and invasion were evaluated. Metastasis was evaluated by examining EMT markers through Western blotting. Gene interaction was determined with ChIP, RIP, RNA pull-down, and luciferase activity assays. A mouse model of a subcutaneous tumor was used to determine the activity of LINC02454 knockdown in vivo. We found that LINC02454 was highly expressed in THCA, and its upregulation was associated with poor survival. The knockdown of LINC02454 repressed colony formation, migration, and invasion. Moreover, loss of LINC02454 inhibited tumor growth and metastasis in mice. HMGA2 promoted LINC02454 transcription via binding to the LINC02454 promoter, and silencing of HMGA2 suppressed malignant behaviors through downregulation of LINC02454. HMGA2 was a novel functional target of LINC02454 in THCA cells, and knockdown of LINC02454-mediated anti-tumor effects was reversed by HMGA2 overexpression. Mechanically, LINC02454 promoted CREB1 phosphorylation and nuclear translocation, and CREB1 was subsequently bound to the HMGA2 promoter to facilitate its expression. LINC02454 cis-regulates HMGA2 transcription via facilitating CREB1 phosphorylation and nuclear translocation, and, in turn, HMGA2 promotes LINC02454 expression, thus accelerating thyroid carcinoma progression. Our results support therapeutic targets of LINC02454 and HMGA2 for THCA.

Unraveling the Roles of miR-204-5p and HMGA2 in Papillary Thyroid Cancer Tumorigenesis

Thyroid cancer is the most common endocrine malignant tumor with an increasing incidence rate. Although differentiated types of thyroid cancer generally present good clinical outcomes, some dedifferentiate into aggressive and lethal forms. However, the molecular mechanisms governing aggressiveness and dedifferentiation are still poorly understood. Aberrant expression of miRNAs is often correlated to tumor development, and miR-204-5p has previously been identified in papillary thyroid carcinoma as downregulated and associated with aggressiveness. This study aimed to explore its role in thyroid tumorigenesis. To address this, gain-of-function experiments were performed by transiently transfecting miR-204-5p in thyroid cancer cell lines. Then, the clinical relevance of our data was evaluated in vivo. We prove that this miRNA inhibits cell invasion by regulating several targets associated with an epithelial-mesenchymal transition, such as SNAI2, TGFBR2, SOX4 and HMGA2. HMGA2 expression is regulated by the MAPK pathway but not by the PI3K, IGF1R or TGFβ pathways, and the inhibition of cell invasion by miR-204-5p involves direct binding and repression of HMGA2. Finally, we confirmed in vivo the relationship between miR-204-5p and HMGA2 in human PTC and a corresponding mouse model. Our data suggest that HMGA2 inhibition offers promising perspectives for thyroid cancer treatment.

HMGA2 regulation by miRNAs in cancer: affecting cancer hallmarks and therapy response

High mobility group A 2 (HMGA2) is a protein that modulates the structure of chromatin in the nucleus. Importantly, aberrant expression of HMGA2 occurs during carcinogenesis, and this protein is an upstream mediator of cancer hallmarks including evasion of apoptosis, proliferation, invasion, metastasis, and therapy resistance. HMGA2 targets critical signaling pathways such as Wnt/β-catenin and mTOR in cancer cells. Therefore, suppression of HMGA2 function notably decreases cancer progression and improves outcome in patients. As HMGA2 is mainly oncogenic, targeting expression by non-coding RNAs (ncRNAs) is crucial to take into consideration since it affects HMGA2 function. MicroRNAs (miRNAs) belong to ncRNAs and are master regulators of vital cell processes, which affect all aspects of cancer hallmarks. Long ncRNAs (lncRNAs) and circular RNAs (circRNAs), other members of ncRNAs, are upstream mediators of miRNAs. The current review intends to discuss the importance of the miRNA/HMGA2 axis in modulation of various types of cancer, and mentions lncRNAs and circRNAs, which regulate this axis as upstream mediators. Finally, we discuss the effect of miRNAs and HMGA2 interactions on the response of cancer cells to therapy. Regarding the critical role of HMGA2 in regulation of critical signaling pathways in cancer cells, and considering the confirmed interaction between HMGA2 and one of the master regulators of cancer, miRNAs, targeting miRNA/HMGA2 axis in cancer therapy is promising and this could be the subject of future clinical trial experiments.

HMGA2 as a Critical Regulator in Cancer Development

The high mobility group protein 2 (HMGA2) regulates gene expression by binding to AT-rich regions of DNA. Akin to other DNA architectural proteins, HMGA2 is highly expressed in embryonic stem cells during embryogenesis, while its expression is more limited at later stages of development and in adulthood. Importantly, HMGA2 is re-expressed in nearly all human malignancies, where it promotes tumorigenesis by multiple mechanisms. HMGA2 increases cancer cell proliferation by promoting cell cycle entry and inhibition of apoptosis. In addition, HMGA2 influences different DNA repair mechanisms and promotes epithelial-to-mesenchymal transition by activating signaling via the MAPK/ERK, TGFβ/Smad, PI3K/AKT/mTOR, NFkB, and STAT3 pathways. Moreover, HMGA2 supports a cancer stem cell phenotype and renders cancer cells resistant to chemotherapeutic agents. In this review, we discuss these oncogenic roles of HMGA2 in different types of cancers and propose that HMGA2 may be used for cancer diagnostic, prognostic, and therapeutic purposes.

High mobility group A protein-2 as a tumor cancer diagnostic and prognostic marker: a systematic review and meta-analysis

High mobility group A protein-2 (HMGA2) is an architectural transcription factor that binds to the A/T-rich DNA minor groove and is responsible for regulating transcriptional activity of multiple genes indirectly through chromatin change and assembling enhanceosome. HMGA2 is overexpressed in multiple tumor types, suggesting its involvement in cancer initiation and progression, thus, making it an ideal candidate for cancer diagnostic and prognostic. We performed a systematic review to examine the role of HMGA2 as a universal tumor cancer diagnostic and prognostic marker. We used Reporting Recommendations for Tumor Marker Prognostic Studies to systematically search OvidMedline, PubMed, and the Cochrane Library for English language studies, published between 1995 and June 2019. Meta-analysis provided pooled risk estimates and their 95% confidence intervals (CIs) for an association between overall survival and recurrence of cancers for studies with available estimates. We identified 42 eligible studies with a total of 5123 tumor samples in 15 types of cancer. The pooled percentage of HMGA2 gene expression in tumor samples was 65.14%. Meta-analysis showed that cancer patients with HMGA2 positive have significantly reduced survival, compared to patients without HMGA2 gene [pooled-hazard ratio (HR) = 1.85, 95% CI 1.48-2.22]. There was a positive association between cancer patients with HMGA2 overexpression and cancer recurrence though this association did not reach significance (pooled-HR = 1.44, 95% CI 0.80-2.07). Overexpression of HMGA2 was found in 15 types of cancer. There was an association between HMGA2 overexpression with reduced survival of cancer patients. HMGA2 is thus considered a promising universal tumor marker for prognostics.

Combined quantitation of HMGA2 mRNA, microRNAs, and mitochondrial-DNA content enables the identification and typing of thyroid tumors in fine-needle aspiration smears

Background

Analysis of molecular markers in addition to cytological analysis of fine-needle aspiration (FNA) samples is a promising way to improve the preoperative diagnosis of thyroid nodules. Nonetheless, in clinical practice, applications of existing diagnostic solutions based on the detection of somatic mutations or analysis of gene expression are limited by their high cost and difficulties with clinical interpretation.

The aim of our work was to develop an algorithm for the differential diagnosis of thyroid nodules on the basis of a small set of molecular markers analyzed by real-time PCR.

Methods

A total of 494 preoperative FNA samples of thyroid goiters and tumors from 232 patients with known histological reports were analyzed: goiter, 105 samples (50 patients); follicular adenoma, 101 (48); follicular carcinoma, 43 (28); Hürthle cell carcinoma, 25 (11); papillary carcinoma, 121 (56); follicular variant of papillary carcinoma, 80 (32); and medullary carcinoma, 19 (12). Total nucleic acids extracted from dried FNA smears were analyzed for five somatic point mutations and two translocations typical of thyroid tumors as well as for relative concentrations of HMGA2 mRNA and 13 microRNAs and the ratio of mitochondrial to nuclear DNA by real-time PCR. A decision tree–based algorithm was built to discriminate benign and malignant tumors and to type the thyroid cancer. Leave-p-out cross-validation with five partitions was performed to estimate prediction quality. A comparison of two independent samples by quantitative traits was carried out via the Mann–Whitney U test.

Results

A minimum set of markers was selected (levels of HMGA2 mRNA and miR-375, − 221, and -146b in combination with the mitochondrial-to-nuclear DNA ratio) and yielded highly accurate discrimination (sensitivity = 0.97; positive predictive value = 0.98) between goiters with benign tumors and malignant tumors and accurate typing of papillary, medullary, and Hürthle cell carcinomas. The results support an alternative classification of follicular tumors, which differs from the histological one.

Conclusions

The study shows the feasibility of the preoperative differential diagnosis of thyroid nodules using a panel of several molecular markers by a simple PCR-based method. Combining markers of different types increases the accuracy of classification.

Long noncoding RNA ZFAS1 promotes progression of papillary thyroid carcinoma by sponging miR-590-3p and upregulating HMGA2 expression

Background

Thyroid cancer is the most common endocrine malignancy, papillary thyroid carcinoma (PTC) is the main form of thyroid cancer. The long non-coding RNA (lncRNA) zinc finger antisense 1 (ZFAS1) is highly expressed in various cancer tissues and it has been shown to function as a tumor promoter in various cellular processes. However, the role of ZFAS1 in PTC is not well understood currently. Thus, this study aimed to explore the potential roles of ZFAS1 in the development and progression of PTC.

Material and methods

PTC tissues (n=80) and noncancerous tissues were collected. Gain- and loss-of-function assays were performed to determine the effect of ZFAS1 on proliferation in K-1 and TPC-1 cells. The ZFAS1/mir-590-3P/HMGA2 aixs were analysed in PTC cell lines.

Results

We found that the expression of ZFAS1 was increased in PTC tissues and four PTC cell lines (B-CPAP, IHH-4, TPC-1, and K-1). The gain- and loss-of-function assays showed that overexpressing ZFAS1 promoted cell proliferation and inhibited cell apoptosis in PTC cells in vitro. We demonstrated that knockdown of ZFAS1 inhibits tumor growth and upregulation of ZFAS1 promotes tumor growth in vivo. Bioinformatics analysis revealed that miR-590-3p targeted the 3ʹ-UTR of ZFAS1. The double luciferase reporter and RNA-binding protein immunoprecipitation assay demonstrated that miR-590-3p is a target of ZFAS1. Rescue experiments confirmed that miR-590-3p could reverse the effect of ZFAS1 on PTC cells. Moreover, we identified high mobility group AT-hook 2 (HMGA2) to be a downstream target of miR-590-3p and ZFAS1 which activates HMGA2 expression by sponging to miR-590-3p.

Conclusion

High ZFAS1 expression level was associated with the progression of PTC, and ZFAS1 contributed to PTC progression via miR-590-3p/HMGA2 regulatory aixs. Therefore, ZFAS1 might be a potential therapeutic target for PTC intervention.

Oncological role of HMGA2 (Review)

The high mobility group A2 (HMGA2) protein is a non‑histone architectural transcription factor that modulates the transcription of several genes by binding to AT‑rich sequences in the minor groove of B‑form DNA and alters the chromatin structure. As a result, HMGA2 influences a variety of biological processes, including the cell cycle process, DNA damage repair process, apoptosis, senescence, epithelial‑mesenchymal transition and telomere restoration. In addition, the overexpression of HMGA2 is a feature of malignancy, and its elevated expression in human cancer predicts the efficacy of certain chemotherapeutic agents. Accumulating evidence has suggested that the detection of HMGA2 can be used as a routine procedure in clinical tumour analysis.

Prognostic value of high mobility group protein A2 (HMGA2) over-expression in cancer progression

The high mobility group A2 (HMGA2; also called HMGI-C) gene is an architectural transcription factor that belonging to the high mobility group AT-hook (HMGA) gene family. HMGA2 is aberrantly regulated in several human tumors. Over-expression of HMGA2 is correlated with a higher risk of metastasis and an unfavorable prognosis in patients with cancer. We performed a meta-analysis to determine the clinic-pathological and prognostic value of HMGA2 overexpression in different human tumors. A comprehensive literature search was performed using PubMed, Embase, Cochrane Library, Scopus, MEDLINE, Google Scholar and ISI Web of Science. Hazard ratios (HRs)/odds ratios (ORs) and their 95% confidence intervals (CIs) were used to assess the strength of the association between HMGA2 expression and overall survival (OS)/progression free survival (PFS)/disease free survival (DFS). A total of 5319 patients with 19 different types of cancer from 35 articles were evaluated. Pooled data analysis indicated that increased HMGA2 expression in cancer patients predicted a poor OS (HR = 1.70; 95% CI = 1.6-1.81; P < 0.001; fixed-effect model). In subgroup analyses, high HMGA2 expression was particularly associated with poor OS in individuals with gastrointestinal (GI) cancer (HR = 1.89, 95% CI: 1.83-1.96; fixed-effect model) and HNSCC cancer (HR-1.78, 95%CI: 1.44-2.21; fixed-effect model). Over-expression of HMGA2 was associated with vascular invasion (OR = 0.16, 95% CI = 0.05-0.49; P = 0.001) and lymphatic invasion (OR = 1.89, 95% CI = 1.06-3.38; P = 0.032). Further studies should be conducted to validate the prognostic value of HMGA2 for patients with GI cancers.

Diagnostic performance of HMGA2 gene expression for differentiation of malignant thyroid nodules: A systematic review and meta-analysis

OBJECTIVE

The purpose of the current study was to investigate the diagnostic performance of high mobility group A2 (HMGA2) gene expression for differentiation of malignant thyroid nodules through a systematic review and meta-analysis.

DESIGN

The MEDLINE/PubMed and EMBASE database, from the earliest available date of indexing through 10 April 2018, were searched for studies evaluating the diagnostic performance of HMGA2 expression for differentiation of thyroid nodules.

METHODS

We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic (ROC) curves.

RESULTS

Across 7 studies, the pooled sensitivity for HMGA2 expression was 0.78 (95% CI; 0.67-0.86) with heterogeneity (I²  = 86.6) and a pooled specificity of 0.94 (95% CI: 0.85-0.98) with heterogeneity (I²  = 94.7). Likelihood ratio (LR) syntheses gave an overall positive likelihood ratio (LR+) of 12.6 (95% CI: 5.1-31.3) and negative likelihood ratio (LR-) of 0.24 (95% CI: 0.15-0.36). The pooled diagnostic odds ratio (DOR) was 53 (95% CI: 18-159). Hierarchical summary ROC curve indicates that the areas under the curve were 0.92 (95% CI: 0.89-0.94). In meta-regression analysis, no definite variable was the source of the study heterogeneity.

CONCLUSION

The current meta-analysis showed the moderate sensitivity and high specificity of HMGA2 expression for differentiation of malignant thyroid nodules. The likelihood ratio scatter-gram suggested that HMGA2 expression analysis could be useful for confirmation of the presence of malignant thyroid nodules. Considering the heterogeneity of included studies, further large prospective studies are necessary to confirm these results.

MicroRNA-599 targets high-mobility group AT-hook 2 to inhibit cell proliferation and invasion in clear cell renal carcinoma

Dysregulation of microRNAs (miRNAs) is associated with the occurrence and development of clear cell renal cell carcinoma (ccRCC) through their participation in a number of critical biological processes. Therefore, an in‑depth investigation into miRNAs and their biological roles within ccRCC may provide useful insights and lead to the identification of novel therapeutic methods for patients with ccRCC. miRNA‑599 (miR‑599) serves critical roles in different types of human cancer. However, the expression pattern, biological function and molecular mechanism of miR‑599 in ccRCC remain unknown. The present study aimed to detect the expression level of miR‑599 in ccRCC, examine its effect on ccRCC progression and further explore the possible underlying mechanisms. It was observed that miR‑599 was significantly underexpressed in ccRCC tissues and cell lines compared with the control. Functional assays revealed that restored expression of miR‑599 restricted the proliferation and invasion of ccRCC cells. Bioinformatics analysis, luciferase reporter assay, reverse transcription‑quantitative polymerase chain reaction and western blot analysis demonstrated that high‑mobility group AT‑hook 2 (HMGA2) was a direct target of miR‑599 in ccRCC. HMGA2 knockdown simulated the suppressive effects caused by miR‑599 overexpression in ccRCC. Recovered HMGA2 expression partially rescued the miR‑599‑mediated inhibition of ccRCC proliferation and invasion. These results suggest that miR‑599 may serve tumour suppressive roles in ccRCC by directly targeting HMGA2, indicating that miR‑599 may have potential as a treatment for patients with ccRCC.

Thyroid follicular adenomas and carcinomas: molecular profiling provides evidence for a continuous evolution

Non-autonomous thyroid nodules are common in the general population with a proportion found to be cancerous. A current challenge in the field is to be able to distinguish benign adenoma (FA) from preoperatively malignant thyroid follicular carcinoma (FTC), which are very similar both histologically and genetically. One controversial issue, which is currently not understood, is whether both tumor types represent different molecular entities or rather a biological continuum. To gain a better insight into FA and FTC tumorigenesis, we defined their molecular profiles by mRNA and miRNA microarray. Expression data were analyzed, validated by qRT-PCR and compared with previously published data sets. The majority of deregulated mRNAs were common between FA and FTC and were downregulated, however FTC showed additional deregulated mRNA. Both types of tumors share deregulated pathways, molecular functions and biological processes. The additional deregulations in FTC include the lipid transport process that may be involved in tumor progression. The strongest candidate genes which may be able to discriminate follicular adenomas and carcinomas, CRABP1, FABP4 and HMGA2, were validated in independent samples by qRT-PCR and immunohistochemistry. However, they were not able to adequately classify FA or FTC, supporting the notion of continuous evolving tumors, whereby FA and FTC appear to show quantitative rather than qualitative changes. Conversely, miRNA expression profiles showed few dysregulations in FTC, and even fewer in FA, suggesting that miRNA play a minor, if any, role in tumor progression.

HMGA2 Gene Expression in Fine-needle Aspiration Samples of Thyroid Nodules as a Marker for Preoperative Diagnosis of Thyroid Cancer

There is a great interest in molecular markers that would help in the preoperative diagnosis of malignant thyroid nodules in cases of indeterminate fine-needle aspiration cytology. The aim of this study was to determine the diagnostic accuracy of HMGA2 gene expression in discriminating benign from malignant thyroid nodules. In this study, 237 preoperative thyroid fine-needle aspiration samples were analyzed prospectively for the expression of the HMGA2 gene by real-time reverse transcription polymerase chain reaction. The results were evaluated against the postoperative histopathologic diagnosis or definitive cytologic diagnosis in cases of nodular goiter and Hashimoto thyroiditis. Among 237 samples from patients with thyroid nodules that were analyzed, 231 were adequate for real-time reverse transcription polymerase chain reaction analysis. With a cutoff value of 8.71 for relative gene expression, HMGA2 was positive in 19 (16.4%) of 116 nodular goiter, 1 (2.6%) of 39 Hashimoto thyroiditis, 9 (28.1%) of 32 follicular adenoma, 0 (0%) of 5 Hurthle cell adenoma, 32 (88.9%) of 36 papillary carcinoma, and 3 (100%) of 3 follicular carcinoma samples. In discriminating between malignant and benign thyroid nodules, HMGA2 has shown specificity of 84.5%, sensitivity of 91.9%, positive predictive value of 53.1%, and negative predictive value of 98.2%. High sensitivity and negative predictive value of HMGA2 for preoperative detection of malignant thyroid nodules shown in this study indicate that it may have a role as an ancillary marker in cytology in the management of patients with thyroid nodules.

Roles of microRNA let-7b in papillary thyroid carcinoma by regulating HMGA2

The incidence of thyroid cancer has increased significantly in the last decade, and the most frequent type of this cancer is papillary thyroid carcinoma. MicroRNAs have been demonstrated to be abnormally expressed in tumors and associated with the development of the tumors. Our aim was to analyze the role and molecular mechanisms of tumor suppressor let-7b in the papillary thyroid carcinoma. Expression of let-7b and high-mobility group A2 in papillary thyroid carcinoma tissues and cell lines was assessed using quantitative reverse transcription polymerase chain reaction and western blot analysis. To explore the role of let-7b or high-mobility group A2 in the BCPAP and TPC-1 cells, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Transwell methods were used. Let-7b expression was significantly downregulated while expression of high-mobility group A2 was upregulated dramatically in papillary thyroid carcinoma tissues and cells compared with that in normal thyroid tissues and cells. In addition, overexpression of let-7b or knockdown of high-mobility group A2 inhibited cell migration and invasion compared with that of control. Besides, high-mobility group A2 was negatively regulated by let-7b in BCPAP cells. Moreover, high-mobility group A2 reintroduction reversed the anti-proliferation, anti-migration, and anti-invasion roles of let-7b. Let-7b might function as a tumor suppressor in papillary thyroid carcinoma by suppressing the expression of high-mobility group A2, and therefore might provide a promising therapeutic target for patients with papillary thyroid carcinoma.

HMGA2 plays an important role in Cr (VI)-induced autophagy

Cr (VI) is mutagenic and carcinogenic, but the mechanism is unclear. In this study, the involvement of high mobility group A2 (HMGA2) in Cr (VI)-induced autophagy was investigated. Cr (VI) treatment induced formation of autophagosomes, increased expression of LC3II, Atg12-Atg5, Atg4, Atg10, HMGA1 and HMGA2 proteins, and decreased the expression of p62 in A549 cells. Silencing of HMGA2 gene by siRNA blocked Cr (VI)-induced formation of autophagosomes, expression of LC3II, Atg12-Atg5, Atg10 and reduction of p62. Overexpression of HMGA2 in HEK 293 and HeLa cells could induce the expression of LC3II, Atg12-Atg5 and Atg10, and decrease the expression of p62. Although the protein level of Atg12-Atg5 conjugation changed after Cr (VI) treatment, silencing of HMGA2 and overexpression of HMGA2, both the proteins and mRNA levels of Atg12 and Atg5 were not changed significantly. ChIP assay demonstrated that HMGA2 protein directly bound to the promoter sequence of Atg10 gene, which modulated the conjugation of Atg12-Atg5. Interestingly, 3-MA markedly prevented Cr (VI)-induced cell growth of A549 cells. Our further in vivo study confirmed that the expression of HMGA1, HMGA2, LC3II, Atg12-Atg5, Atg4, Atg5, Atg7, Atg10, Atg12, Beclin 1 were increased and p62 was reduced in lung tissues of Cr (VI)-treated BALB/c mice. Combining, our data demonstrated that HMGA2 plays an important role in Cr (VI)-induced autophagy and the mechanism underlies Atg12-Atg5 conjugation modulated by HMGA2-dependent transcriptional regulation of Atg10. This suggests that HMGA2 might be an important biomarker in Cr (VI)-induced autophagy, cell-growth or other toxicities.

HMGA2 promotes vasculogenic mimicry and tumor aggressiveness by upregulating Twist1 in gastric carcinoma

High mobility group protein A2 (HMGA2) is a transcription factor that plays an important role in the invasion and metastasis of gastric carcinoma (GC). The term vasculogenic mimicry (VM) refers to the unique ability of aggressive tumour cells to mimic the pattern of embryonic vasculogenic networks. However, the relationship between HMGA2 and VM formation remains unclear. In the present study, we examined concomitant HMGA2 expression and VM in 228 human GC samples and 4 GC cell lines. Our data indicate that HMGA2 is not only significantly associated with VM formation but also influences the prognosis of patients with gastric carcinoma. Overexpression of HMGA2 significantly increased cell motility, invasiveness, and VM formation both in vitro and in vivo. A luciferase reporter assay, Co-IP and ChIP demonstrated that HMGA2 induced the expression of Twist1 and VE-cadherin by binding to the Twist1 promoter. Moreover, we observed a decrease in VE-cadherin following Twist1 knockdown in cells overexpressing HMGA2. This study indicates that HMGA2 promotes VM in GC via Twist1-VE-cadherin signalling and influences the prognosis of patients with GC.

Long noncoding RNA HIT000218960 promotes papillary thyroid cancer oncogenesis and tumor progression by upregulating the expression of high mobility group AT-hook 2 (HMGA2) gene

Accumulating evidence suggests that long noncoding RNAs (lncRNAs) play an important role in oncogenesis and tumor progression. However, our knowledge of lncRNAs in thyroid cancer is still limited. To explore the crucial lncRNAs involved in oncogenesis of papillary thyroid cancer (PTC), we acquired data of differentially expressed lncRNAs between PTC tissues and paired adjacent noncancerous thyroid tissues through lncRNA microarray. In the microarray data, we observed that a newly identified lncRNA, HIT000218960, was significantly upregulated in PTC tissues and associated with a well-known oncogene, high mobility group AT-hook 2 (HMGA2) gene. Both in normal thyroid tissues and PTC tissues, the expression of HIT000218960 was significantly positively correlated with that of HMGA2 mRNA. Knockdown of HIT000218960 in PTC cells resulted in downregulation of HMGA2. In addition, functional assays indicated that inhibition of HIT000218960 in PTC cells suppressed cell proliferation, colony formation, migration and invasion in vitro. Increased HIT000218960 expression in PTC tissues was obviously correlated with lymph node metastasis and multifocality, as well as TNM stage. Those findings suggest that HIT000218960 might acts as a tumor promoter through regulating the expression of HMGA2.

Genome-wide detection of DNase I hypersensitive sites in single cells and FFPE tissue samples

DNase I hypersensitive sites (DHSs) provide important information on the presence of transcriptional regulatory elements and the state of chromatin in mammalian cells. Conventional DNase sequencing (DNase-seq) for genome-wide DHSs profiling is limited by the requirement of millions of cells. Here we report an ultrasensitive strategy, called single-cell DNase sequencing (scDNase-seq) for detection of genome-wide DHSs in single cells. We show that DHS patterns at the single-cell level are highly reproducible among individual cells. Among different single cells, highly expressed gene promoters and enhancers associated with multiple active histone modifications display constitutive DHS whereas chromatin regions with fewer histone modifications exhibit high variation of DHS. Furthermore, the single-cell DHSs predict enhancers that regulate cell-specific gene expression programs and the cell-to-cell variations of DHS are predictive of gene expression. Finally, we apply scDNase-seq to pools of tumour cells and pools of normal cells, dissected from formalin-fixed paraffin-embedded tissue slides from patients with thyroid cancer, and detect thousands of tumour-specific DHSs. Many of these DHSs are associated with promoters and enhancers critically involved in cancer development. Analysis of the DHS sequences uncovers one mutation (chr18: 52417839G>C) in the tumour cells of a patient with follicular thyroid carcinoma, which affects the binding of the tumour suppressor protein p53 and correlates with decreased expression of its target gene TXNL1. In conclusion, scDNase-seq can reliably detect DHSs in single cells, greatly extending the range of applications of DHS analysis both for basic and for translational research, and may provide critical information for personalized medicine.

HMGA1/HMGA2 protein expression and prognostic implications in gastric cancer

BACKGROUND

The high mobility group A1 (HMGA1) and high mobility group A2 (HMGA2) proteins are architectural transcription factors that have been implicated in the pathogenesis and progression of multiple malignant tumors, including gastric cancer. The aim of this study was to explore the roles of HMGA1 and HMGA2 in gastric carcinogenesis.

METHODS

The expression of HMGA1 and HMGA2 was examined in 110 gastric adenocarcinomas, 29 gastric adenomas, and 30 normal controls. The results were correlated with the clinicopathological parameters of the tumors and patient outcome.

RESULTS

The levels of HMGA1 and HMGA2 proteins were significantly increased in gastric cancer samples compared with adenoma and normal gastric tissues. High HMGA1 nuclear immunoreactivity was not correlated with clinicopathological features; however, high levels of HMGA2 protein were significantly associated with T stage, N stage, lymphatic invasion, perineural invasion, and TNM stage. Moreover, HMGA2 expression was significantly associated with shorter recurrence free survival. Multivariate analysis showed that HMGA2 expression was an independent prognostic factor for tumor recurrence.

CONCLUSIONS

Our results suggest that HMGA1 and HMGA2 are implicated in gastric carcinogenesis and may play a role in tumor progression towards a more malignant phenotype. The HMGA2 protein may be a useful prognostic marker for predicting tumor recurrence.

The diagnostic utility of combination of HMGA2 and IMP3 qRT-PCR testing in thyroid neoplasms

The diagnosis of malignant thyroid tumors in some cytologic and histologic specimens remains challenging. High-mobility group A2 (HMGA2) expression and insulin-like growth factor II mRNA-binding protein-3 (IMP3) expression were evaluated by relative quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The aim of this study was to evaluate whether the combination of HMGA2 and IMP3 qRT-PCR was diagnostically useful in differentiating benign from malignant thyroid neoplasms. Fine-needle aspiration (FNA) specimens from 120 patients including 56 benign lesions and 64 carcinomas were used. The available 80 corresponding formalin-fixed paraffin-embedded (FFPE) thyroid tissues from 66 patients were also included in this study. HMGA2 and IMP3 expression levels were detected by qRT-PCR and reported as relative fold change after normalizing with a calibrator. The diagnostic utilities of HMGA2 and IMP3 qRT-PCR tests were evaluated individually and in combination. In FNA specimens, HMGA2 and IMP3 expression was consistently higher in thyroid malignancies compared with benign lesions in all subgroups except in Hürthle cell tumors. After exclusion of Hürthle cell tumors, the sensitivity was 90.2% for HMGA2, 88.2% for IMP3, and 98% for HMGA2+IMP3; the specificity was 97.1% for HMGA2, 79.4% for IMP3, and 79.4% for HMGA+IMP3. qRT-PCR data showed similar results in FFPE tissues: the sensitivity was 84.2% for HMGA2, 85.7% for IMP3, and 94.7% for HMGA2+IMP3; the specificity was 96.9% for HMGA2, 91.2% for IMP3, and 90.6% for HMGA2+IMP3. qRT-PCR data were concordant between FNA and FFPE samples for HMGA2 (97.4%) and IMP3 (96.9%). The results indicate that HMGA2 qRT-PCR with high specificity may be a useful ancillary technique to assist in the classification of difficult thyroid specimens, excluding Hürthle cell tumors. The HMGA2 and IMP3 qRT-PCR combination model with increased sensitivity and negative predictive value (96.4%) may be useful in screening thyroid cytology specimens.

Integrated network analysis and logistic regression modeling identify stage-specific genes in Oral Squamous Cell Carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) is associated with substantial mortality and morbidity but, OSCC can be difficult to detect at its earliest stage due to its molecular complexity and clinical behavior. Therefore, identification of key gene signatures at an early stage will be highly helpful.

METHODS

The aim of this study was to identify key genes associated with progression of OSCC stages. Gene expression profiles were classified into cancer stage-related modules, i.e., groups of genes that are significantly related to a clinical stage. For prioritizing the candidate genes, analysis was further restricted to genes with high connectivity and a significant association with a stage. To assess predictive power of these genes, a classification model was also developed and tested by 5-fold cross validation and on an independent dataset.

RESULTS

The identified genes were enriched for significant processes and functional pathways, and various genes were found to be directly implicated in OSCC. Forward and stepwise, multivariate logistic regression analyses identified 13 key genes whose expression discriminated early- and late-stage OSCC with predictive accuracy (area under curve; AUC) of ~0.81 in a 5-fold cross-validation strategy.

CONCLUSIONS

The proposed network-driven integrative analytical approach can identify multiple genes significantly related to an OSCC stage; the classification model that is developed with these genes may help to distinguish cancer stages. The proposed genes and model hold promise for monitoring of OSCC stage progression, and our findings may facilitate cancer detection at an earlier stage, resulting in improved treatment outcomes.

HMGA2 Expression in Renal Carcinoma and its Clinical Significance

Background

The objective of this study is to detect HMGA2 expression in renal carcinoma to explore its relationship with clinicopathology and its significance in prognosis.

Methods

Expressions of HMGA2 mRNA and protein were detected in 50 renal carcinoma specimens, 50 corresponding adjacent normal kidney tissue samples and 40 renal benign tumour specimens via reverse transcription polymerase chain reaction and immunohistochemical assay. Expression analysis was performed along with clinical data analysis.

Results

The relative expression levels of HMGA2 mRNA in renal carcinoma, renal benign tumour tissues and adjacent normal renal tissues were 0.84±0.23, 0.19±0.06 and 0.08±0.04, respectively. HMGA2 protein positive rates were 68.0%, 7.5% and 2.0%, with a significant difference (P<0.05). HMGA2 expression was not significantly correlated with gender, age, tumour size and histological type (P>0.05), but was significantly correlated with TNM stages and lymph node metastasis (P<0.05).

Conclusions

The expressions of HMGA2 gene and protein in renal carcinoma were closely correlated with tumour formation, progression and metastasis. HMGA2 may become a powerful new pathological marker and prognostic factor for renal carcinoma.

Genome-wide expression analysis suggests a crucial role of dysregulation of matrix metalloproteinases pathway in undifferentiated thyroid carcinoma

Background

Thyroid cancer (TC) is the most common malignant cancer of the Endocrine System. Histologically, there are three main subtypes of TC: follicular, papillary and anaplastic. Diagnosing a thyroid tumor subtype with a high level of accuracy and confidence is still a difficult task because genetic, molecular and cellular mechanisms underlying the transition from differentiated to undifferentiated thyroid tumors are not well understood.

A genome-wide analysis of these three subtypes of thyroid carcinoma was carried out in order to identify significant differences in expression levels as well as enriched pathways for non-shared molecular and cellular features between subtypes.

Results

Inhibition of matrix metalloproteinases pathway is a major event involved in thyroid cancer progression and its dysregulation may result crucial for invasiveness, migration and metastasis. This pathway is drastically altered in ATC while in FTC and PTC, the most important pathways are related to DNA-repair activation or cell to cell signaling events.

Conclusion

A progression from FTC to PTC and then to ATC was detected and validated on two independent datasets. Moreover, PTX3, COLEC12 and PDGFRA genes were found as possible candidates for biomarkers of ATC while GPR110 could be tested to distinguish PTC over other tumor subtypes. The genome-wide analysis emphasizes the preponderance of pathway-dysregulation mechanisms over simple gene-malfunction as the main mechanism involved in the development of a cancer phenotype.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1372-0) contains supplementary material, which is available to authorized users.

The Diagnostic Usefulness of HMGA2, Survivin, CEACAM6, and SFN/14-3-3 δ in Follicular Thyroid Carcinoma

Background:

Follicular thyroid carcinoma (FTC) is the second most common thyroid malignancy and its differential diagnosis includes follicular adenoma (FA) and adenomatous goiter (AG). Several ancillary markers have been suggested to aid in the diagnosis of FTC, but the successful use of these methods still needs to be validated.

Methods:

In the present study, we verified the immunoexpression of HMGA2, CEACAM6, survivin, and SFN/14-3-3 δ in lesions including 41 AGs, 72 FAs, and 79 FTCs. We evaluated their diagnostic usefulness, combined with galectin 3, Hector Battifora mesothelial 1 (HBME1), cytokeratin 19, and cyclin D1, in diagnosing FTC.

Results:

The expressions of HBME1 (65.8%) and HMGA2 (55.7%) were significantly higher in FTCs than in FAs and AGs (p<.001 and p=.005, respectively). HBME1 was the only marker that was more frequently expressed in FTCs than in FAs (p=.021) and it was more frequently expressed in follicular neoplasms than in AGs (p<.001). Among the novel markers, the combination of HMGA2 and HBME1 showed the highest sensitivity (72.2%) and specificity (76.1%) for diagnosing FTC. CEACAM6, survivin, and SFN/14-3-3 δ were barely expressed in most cases.

Conclusions:

Our present results show that only HMGA2 can be beneficial in differentiating FTC using the novel markers.

Toll-like receptor expression in the blood and brain of patients and a mouse model of Parkinson's disease

BACKGROUND

Accumulating evidence supports a role for the immune system in the pathogenesis of Parkinson's disease. Importantly, recent preclinical studies are now suggesting a specific contribution of inflammation to the α-synuclein-induced pathology seen in this condition.

METHODS

We used flow cytometry and western blots to detect toll-like receptor 2 and 4 expression in blood and brain samples of Parkinson's disease patients and mice overexpressing human α-synuclein. To further assess the effects of α-synuclein overexpression on the innate immune system, we performed a longitudinal study using Thy1.2-α-synuclein mice that expressed a bicistronic DNA construct (reporter genes luciferase and green fluorescent protein) under the transcriptional control of the murine toll-like receptor 2 promoter.

RESULTS

Here, we report increases in toll-like receptors 2 and 4 expression in circulating monocytes and of toll-like receptor 4 in B cells and in the caudate/putamen of Parkinson's disease patients. Monthly bioluminescence imaging of Thy1.2-α-synuclein mice showed increasing toll-like receptor 2 expression from 10 months of age, although no change in toll-like receptor 2 and 4 expression was observed in the blood and brain of these mice at 12 months of age. Dexamethasone treatment starting at 5 months of age for 1 month significantly decreased the microglial response in the brain of these mice and promoted functional recovery as observed using a wheel-running activity test.

CONCLUSION

Our results show that toll-like receptors 2 and 4 are modulated in the blood and brain of Parkinson's disease patients and that overexpression of α-synuclein leads to a progressive microglial response, the inhibition of which has a beneficial impact on some motor phenotypes of an animal model of α-synucleinopathy.

Cancer-associated fibroblasts induce high mobility group box 1 and contribute to resistance to doxorubicin in breast cancer cells

Background

Cancer-associated fibroblasts and high mobility group box 1 (HMGB1) protein have been suggested to mediate cancer progression and chemotherapy resistance. The role of such fibroblasts in HMGB1 production in breast cancer is unclear. This study aimed to investigate the effects of cancer-associated fibroblasts on HMGB1 expression in breast cancer cells and its role in chemotherapeutic response.

Methods

Breast cancer-associated fibroblasts (BCFs) and non-tumor-associated fibroblasts (NTFs) were isolated from human breast cancers or adjacent normal tissues and established as primary cultures in vitro. After confirmation of the activated status of these fibroblasts, conditioned-media (CM) were collected and applied to MDA-MB-231 human triple negative breast cancer cells. The levels of intracellular and extracellular HMGB1 were measured by real-time PCR and/or Western blot. The response of BCF-CM-pre-treated cancer cells to doxorubicin (Dox) was compared with those pre-treated with NTF-CM or control cultures. The effect of an HMGB1 neutralizing antibody on Dox resistance induced by extracellular HMGB1 from non-viable Dox-treated cancer cells or recombinant HMGB1 was also investigated.

Results

Immunocytochemical analysis revealed that BCFs and NTFs were alpha-smooth muscle actin (ASMA) positive and cytokeratin 19 (CK19) negative cells: a phenotype consistent with that of activated fibroblasts. We confirmed that the CM from BCFs (but not NTFs), could significantly induce breast cancer cell migration. Intracellular HMGB1 expression was induced in BCF-CM-treated breast cancer cells and also in Dox-treated cells. Extracellular HMGB1 was strongly expressed in the CM after Dox-induced MDA-MB-231 cell death and was higher in cells pre-treated with BCF-CM than NTF-CM. Pre-treatment of breast cancer cells with BCF-CM induced a degree of resistance to Dox in accordance with the increased level of secreted HMGB1. Recombinant HMGB1 was shown to increase Dox resistance and this was associated with evidence of autophagy. Anti-HMGB1 neutralizing antibody significantly reduced the effect of extracellular HMGB1 released from dying cancer cells or of recombinant HMGB1 on Dox resistance.

Conclusions

These findings highlight the potential of stromal fibroblasts to contribute to chemoresistance in breast cancer cells in part through fibroblast-induced HMGB1 production.

Coexpression of HMGA2 and Oct4 predicts an unfavorable prognosis in human gastric cancer

High mobility group protein A2 (HMGA2) and octamer-binding transcription factor 4 (Oct4) are transcription factors that play major roles in the acquisition of cancer stemness phenotypes and tumorigenicity of malignant neoplasms. The aim of this study was to analyze the association between HMGA2 and Oct4 expression and various clinicopathologic features in gastric cancer patients including invasion, metastasis, and clinical prognosis, in addition to overall survival. Immunohistochemistry was performed to explore the expression of HMGA2 and Oct4 in 158 gastric cancer and surrounding non-tumor tissues. Moreover, HMGA2 and Oct4 mRNA and protein levels were also detected by qRT-PCR and Western blotting, respectively, in 86 clinical tissue specimens and various gastric epithelial cell lines (GES-1, SGC7901, MKN45, and MKN27). Finally, associations between HMGA2 and Oct4 expression and clinicopathological features were analyzed by Pearson correlation coefficient. Survival analysis was performed by univariate and multivariate analyses. Taken together, we found that HMGA2 and Oct4 expression was significantly higher in gastric cancer tissues compared with non-cancerous tissues (P < 0.01), and HMGA2 and Oct4 protein levels were significantly higher in poorly differentiated gastric cancer cell lines (MKN45), moderately differentiated cell lines (SGC7901), and well-differentiated cell lines (MKN28) compared with human immortalized gastric epithelial cell lines (GES-1) (P < 0.01). Elevated HMGA2 and Oct4 levels were significantly associated with poor clinical prognosis (P < 0.05). Further conclusion showed that coexpression of HMGA2 and Oct4 in gastric cancer correlated with tumor invasion, metastasis, and clinical prognosis and predicted an unfavorable clinical outcome. These transcription factors may represent useful biomarkers to identify patients at high risk of postoperative recurrence.

Immunohistochemical study of nuclear ubiquitous casein and cyclin-dependent kinase substrate 1 in invasive breast carcinoma of no special type

The aim of the present study was to investigate the immunohistochemical expression of nuclear ubiquitous casein and cyclin-dependent kinases substrate 1 (NUCKS1) in invasive breast carcinoma of no special type, in association with clinicopathological characteristics, including the tumor grade, frequency of lymph node involvement and distant metastasis. In addition, associations between NUCKS1 and other tumor subtype markers, including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), Ki-67 and cytokeratin 5/6 (CK 5/6), were investigated. NUCKS1 expression was shown to be associated with the formation of distant metastases and lymph node involvement. Furthermore, an association between the presence of NUCKS1 and histological grading was observed. The results confirmed that the expression of NUCKS1 in low grade invasive breast carcinoma of no special type was significantly less common compared with cases of high grade carcinoma. With regard to the additional tumor subtype markers, NUCKS1 expression was demonstrated to be significantly associated with Ki-67 and CK 5/6; however, no association was identified with ER, PR and HER2. Therefore, NUCKS1 may be a novel prognostic marker in the histopathological evaluation of invasive breast carcinoma of no special type.

Generation and characterisation of a canine EGFP-HMGA2 prostate cancer in vitro model

The architectural transcription factor HMGA2 is abundantly expressed during embryonic development. In several malignant neoplasias including prostate cancer, high re-expression of HMGA2 is correlated with malignancy and poor prognosis. The let-7 miRNA family is described to regulate HMGA2 negatively. The balance of let-7 and HMGA2 is discussed to play a major role in tumour aetiology. To further analyse the role of HMGA2 in prostate cancer a stable and highly reproducible in vitro model system is precondition. Herein we established a canine CT1258-EGFP-HMGA2 prostate cancer cell line stably overexpressing HMGA2 linked to EGFP and in addition the reference cell line CT1258-EGFP expressing solely EGFP to exclude EGFP-induced effects. Both recombinant cell lines were characterised by fluorescence microscopy, flow cytometry and immunocytochemistry. The proliferative effect of ectopically overexpressed HMGA2 was determined via BrdU assays. Comparative karyotyping of the derived and the initial CT1258 cell lines was performed to analyse chromosome consistency. The impact of the ectopic HMGA2 expression on its regulator let-7a was analysed by quantitative real-time PCR. Fluorescence microscopy and immunocytochemistry detected successful expression of the EGFP-HMGA2 fusion protein exclusively accumulating in the nucleus. Gene expression analyses confirmed HMGA2 overexpression in CT1258-EGFP-HMGA2 in comparison to CT1258-EGFP and native cells. Significantly higher let-7a expression levels were found in CT1258-EGFP-HMGA2 and CT1258-EGFP. The BrdU assays detected an increased proliferation of CT1258-HMGA2-EGFP cells compared to CT1258-EGFP and native CT1258. The cytogenetic analyses of CT1258-EGFP and CT1258-EGFP-HMGA2 resulted in a comparable hyperdiploid karyotype as described for native CT1258 cells. To further investigate the impact of recombinant overexpressed HMGA2 on CT1258 cells, other selected targets described to underlie HMGA2 regulation were screened in addition. The new fluorescent CT1258-EGFP-HMGA2 cell line is a stable tool enabling in vitro and in vivo analyses of the HMGA2-mediated effects on cells and the development and pathogenesis of prostate cancer.

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.

Correlated expression of HMGA2 and PLAG1 in thyroid tumors, uterine leiomyomas and experimental models

In pleomorphic adenomas of the salivary glands (PASG) recurrent chromosomal rearrangements affecting either 8q12 or 12q14∼15 lead to an overexpression of the genes of the genuine transcription factor PLAG1 or the architectural transcription factor HMGA2, respectively. Both genes are also affected by recurrent chromosomal rearrangements in benign adipocytic tumors as e. g. lipomas and lipoblastomas. Herein, we observed a strong correlation between the expression of HMGA2 and PLAG1 in 14 benign and 23 malignant thyroid tumors. To address the question if PLAG1 can be activated by HMGA2, the expression of both genes was quantified in 32 uterine leiomyomas 17 of which exhibited an overexpression of HMGA2. All leiomyomas with HMGA2 overexpression also revealed an activation of PLAG1 in the absence of detectable chromosome 8 abnormalities affecting the PLAG1 locus. To further investigate if the overexpression of PLAG1 is inducible by HMGA2 alone, HMGA2 was transiently overexpressed in MCF-7 cells. An increased PLAG1 expression was observed 24 and 48 h after transfection. Likewise, stimulation of HMGA2 by FGF1 in adipose tissue-derived stem cells led to a simultaneous increase of PLAG1 mRNA. Altogether, these data suggest that HMGA2 is an upstream activator of PLAG1. Accordingly, this may explain the formation of tumors as similar as lipomas and lipoblastomas resulting from an activation of either of both genes by chromosomal rearrangements.

Evaluation of genetic biomarkers for distinguishing benign from malignant thyroid neoplasms

BACKGROUND

Fine-needle aspiration (FNA) aids in the diagnosis of thyroid nodules. The expression of previously implicated genes was examined to potentially discriminate between benign and malignant thyroid samples.

METHODS

Patients included for study had cytology demonstrating follicular cells of undetermined significance, atypical cells of undetermined significance, follicular neoplasm, or suspicion of malignancy with one of the following postoperative diagnoses: follicular thyroid adenomas, follicular thyroid carcinomas, or follicular variant of papillary thyroid carcinomas (FV-PTCs). FNA and tumor expression of human telomerase reverse transcriptase (hTERT), high-mobility group A2 (HMGA2), and trefoil factor 3/3-galactoside-binding lectin (T/G ratio) were analyzed.

RESULTS

T/G ratios were not significantly different in the malignant and benign groups. HMGA2 was overexpressed in carcinoma states; however, only FV-PTCs were significant (P = .006). Tumor hTERT expression was detected in 25% of follicular thyroid carcinomas, whereas 5% of FV-PTCs and 10% of follicular thyroid adenomas had expression. FNA aspirates showed similar results.

CONCLUSIONS

Although HMGA2 and hTERT showed differential expression, they did not consistently differentiate benign from malignant. Further study based on global gene expression is needed to identify markers that could serve as a diagnostic tool.

Classification of follicular cell-derived thyroid cancer by global RNA profiling

The incidence of thyroid cancer is increasing worldwide and thyroid nodules are a frequent clinical finding. Diagnosing follicular cell-derived cancers is, however, challenging both histopathologically and especially cytopathologically. The advent of high-throughput molecular technologies has prompted many researchers to explore the transcriptome and, in recent years, also the miRNome in order to generate new molecular classifiers capable of classifying thyroid tumours more accurately than by conventional cytopathological and histopathological methods. This has led to a number of molecular classifiers that may differentiate malignant from benign thyroid nodules. Molecular classification models based on global RNA profiles from fine-needle aspirations are currently being evaluated; results are preliminary and lack validation in prospective clinical trials. There is no doubt that molecular classification will not only contribute to our biological insight but also improve clinical and pathological examinations, thus advancing thyroid tumour diagnosis and ultimately preventing superfluous surgery. This review evaluates the status of classification and biological insights gained from molecular profiling of follicular cell-derived thyroid cancers.

HMGA2 elicits EMT by activating the Wnt/β-catenin pathway in gastric cancer

BACKGROUND

The high mobility group protein A2 (HMGA2) is an architectural transcription factor that plays an important role in the development and progression of many malignant neoplasms. High expression of HMGA2 in gastric cancer correlates with invasiveness of cancer and is an independent prognostic factor. The reason for this might be HMGA2 promoting epithelial-mesenchymal transitions (EMT), which is the key process of metastasis for some underlying mechanisms.

AIMS

This study was designed to test whether HMGA2 participates in the EMT and to further understand the underlying mechanisms of EMT promoted by HMGA2.

METHODS

We examined the cell biology and molecular biology changes after overexpression and knockdown HMGA2 of gastric cancer cells in vitro and vivo. To further understand the underlying mechanisms of EMT promoted by HMGA2, based on our previous study, we examined the changes of target genes of HMGA2 after overexpression and knockdown HMGA2 of gastric cancer cells.

RESULTS

The results indicated that overexpressing HMGA2 enabled enhancing the oncogenic properties of gastric epithelial origin cell in vitro and in vivo. Furthermore, our study showed that HMGA2 was able to elicit EMT and regulate several genes which are closely related to the Wnt/β-catenin pathway by directly binding to their promoter thereby activating the Wnt/β-catenin pathway.

CONCLUSIONS

The Wnt/β-catenin pathway activated by HMGA2 might be the underlying mechanism of EMT in gastric cancer cells.

The quest for diagnostic molecular markers for thyroid nodules with indeterminate or suspicious cytology

Thyroid nodules are very common and fine needle aspiration (FNA) is a very sensitive means of diagnosis. However, its limitations include the fact that the cytology reports are often indeterminate or suspicious only. The quest for adjunctive measures to improve its specificity has been ongoing for decades, but significant results have remained elusive. The potential use of diagnostic molecular markers appears to be the most promising area of research at this time.

Regulation of let-7 and its target oncogenes (Review)

MicroRNAs (miRNAs) are highly evolutionarily-conserved non-coding small RNAs, which were first identified in Caenorhabditis elegans. Let-7 miRNA is involved in the regulation of gene expression in cells. Several novel factors and feedback loops involved in the regulation of the synthesis of let-7 have been identified and additional let-7 target genes have been found. Let-7 has also been shown to be significantly correlated with the occurrence and development of cancer and the results of preliminary studies suggest that it is involved in the regulation of oncogenic pathways in numerous types of tumors. Let-7 is, therefore, a potential molecular target for tumor therapy. Thus, this review examined let-7 and the correlation between let-7 and oncogenic pathways in cancer.

Genome-wide analysis of HMGA2 transcription factor binding sites by ChIP on chip in gastric carcinoma cells

High mobility group protein A2 (HMGA2) is an architectural transcription factor that plays an important role in development and progression of malignant neoplasias. Recently, some studies reported that HMGA2 is also implicated in epithelial-mesenchymal transitions (EMT) and cancer stem cells. But the underlying mechanisms of these conditions are poorly understood. Therefore, we established an EMT model of gastric carcinoma cells by overexpressing HMGA2 in vitro, then global mapping of HMGA2 potential transcription factor binding sites was identified by promoter microarray in these cells, and the date obtained from the microarrays were validated via chromatin immunoprecipitation-PCR (ChIP-PCR) and real-time PCR. HMGA2 potential target genes were classified in KEGG database and Gene Ontology (GO) analyses. To our knowledge, this is the first report on the genome-wide analysis of HMGA2 downstream direct targets, and these findings will be valuable in understanding the roles of HMGA2 in EMT.

Decrease in thyroid adenoma associated (THADA) expression is a marker of dedifferentiation of thyroid tissue

Background

Thyroid adenoma associated (THADA) has been identified as the target gene affected by chromosome 2p21 translocations in thyroid adenomas, but the role of THADA in the thyroid is still elusive. The aim of this study was to quantify THADA gene expression in normal tissues and in thyroid hyper- and neoplasias, using real-time PCR.

Methods

For the analysis THADA and 18S rRNA gene expression assays were performed on 34 normal tissue samples, including thyroid, salivary gland, heart, endometrium, myometrium, lung, blood, and adipose tissue as well as on 85 thyroid hyper- and neoplasias, including three adenomas with a 2p21 translocation. In addition, NIS (sodium-iodide symporter) gene expression was measured on 34 of the pathological thyroid samples.

Results

Results illustrated that THADA expression in normal thyroid tissue was significantly higher (p < 0.0001, exact Wilcoxon test) than in the other tissues. Significant differences were also found between non-malignant pathological thyroid samples (goiters and adenomas) and malignant tumors (p < 0.001, Wilcoxon test, t approximation), anaplastic carcinomas (ATCs) and all other samples and also between ATCs and all other malignant tumors (p < 0.05, Wilcoxon test, t approximation). Furthermore, in thyroid tumors THADA mRNA expression was found to be inversely correlated with HMGA2 mRNA. HMGA2 expression was recently identified as a marker revealing malignant transformation of thyroid follicular tumors. A correlation between THADA and NIS has also been found in thyroid normal tissue and malignant tumors.

Conclusions

The results suggest THADA being a marker of dedifferentiation of thyroid tissue.