Epigenetic modulators of thyroid cancer

BRAF mutation, selected miRNAs and genes expression in primary papillary thyroid carcinomas and local lymph node metastases

Mutations in cancer-related genes are now known to be accompanied by epigenetic events in carcinogenesis by modification of the regulatory pathways and expression of genes involved in the pathobiology. Such cancer-related mutations, miRNAs and gene expression may be promising molecular markers of the most common papillary thyroid carcinoma (PTC). However, there are limited data on their relationships. The aim of this study was to analyse the interactions between BRAF mutations, selected microRNAs (miR-21, miR-34a, miR-146b, and miR-9) and the expression of selected genes (LGALS3, NKX2-1, TACSTD2, TPO) involved in the pathogenesis of PTC. The study cohort included 60 primary papillary thyroid carcinomas (PTC) that were classified as classical (PTC/C; n=50) and invasive follicular variant (PTC/F; n=10), and 40 paired lymph node metastases (LNM). BRAF mutation status in primary and recurrent/persistent papillary thyroid carcinomas was determined. The mutation results were compared both between primary and metastatic cancer tissue, and between BRAF mutation status and selected genes and miRNA expression in primary PTC. Furthermore, miRNAs and gene expression were compared between primary PTCs and non-neoplastic tissue, and local lymph node metastatic tumor, respectively. All studied markers showed several significant mutual interactions and contexts. In conclusion, to the best our knowledge, this is the first integrated study of BRAF mutational status, the expression levels of mRNAs of selected genes and miRNAs in primary PTC, and paired LNM.

The impact of iodine deficiency exposure on thyroid nodule cytology and pathology - A single institute, case-control study

OBJECTIVE

The association between follicular carcinoma and iodine deficiency (ID) is based on epidemiological studies and their inherent biases. The aim of the study was to assess the impact of long-term ID exposure on thyroid nodule cytology and final pathology in a distinct group of patients within a single institution.

METHODS

Ethiopian origin patients were compared to an aged-matched group of non-Ethiopian patients. Demographics, risk factors, clinical presentation, cytology and pathology were collected and compared. Final outcomes were cytology and pathology distribution.

RESULTS

A total of 489 (246 Ethiopian, 243 control) nodules of 461 patients (230 and 231 respectively) were included. Ethiopian patients had lower rates of thyroid cancer risk factors (p=0.05). Cytology analysis demonstrated significant group differences (p=0.03), as Ethiopian patients had higher rates of benign cytology (85% vs. 75.7%, respectively). Pathology analysis demonstrated a significantly lower malignancy rate among Ethiopian patients (39.2% (20/51) vs. 63.3% (31/49), p=0.027, respectively). The Ethiopian group had a significant higher rate of follicular carcinoma compared to the control group (25% [5/20] vs. 3.2% [1/31], p=0.034, respectively) and lower rates of papillary thyroid carcinoma (25% [5/20] vs. 61.3% [19/31], p=0.017, respectively).

CONCLUSIONS

The association between ID and FC exists years following immigration and exposure to a better iodine diet, implying that differentiation may be affected in earlier stages and levels of exposure.

Advances and challenges in thyroid cancer: The interplay of genetic modulators, targeted therapies, and AI-driven approaches

Thyroid cancer continues to exhibit a rising incidence globally, predominantly affecting women. Despite stable mortality rates, the unique characteristics of thyroid carcinoma warrant a distinct approach. Differentiated thyroid cancer, comprising most cases, is effectively managed through standard treatments such as thyroidectomy and radioiodine therapy. However, rarer variants, including anaplastic thyroid carcinoma, necessitate specialized interventions, often employing targeted therapies. Although these drugs focus on symptom management, they are not curative. This review delves into the fundamental modulators of thyroid cancers, encompassing genetic, epigenetic, and non-coding RNA factors while exploring their intricate interplay and influence. Epigenetic modifications directly affect the expression of causal genes, while long non-coding RNAs impact the function and expression of micro-RNAs, culminating in tumorigenesis. Additionally, this article provides a concise overview of the advantages and disadvantages associated with pharmacological and non-pharmacological therapeutic interventions in thyroid cancer. Furthermore, with technological advancements, integrating modern software and computing into healthcare and medical practices has become increasingly prevalent. Artificial intelligence and machine learning techniques hold the potential to predict treatment outcomes, analyze data, and develop personalized therapeutic approaches catering to patient specificity. In thyroid cancer, cutting-edge machine learning and deep learning technologies analyze factors such as ultrasonography results for tumor textures and biopsy samples from fine needle aspirations, paving the way for a more accurate and effective therapeutic landscape in the near future.

Multi-Omics and Management of Follicular Carcinoma of the Thyroid

Follicular thyroid carcinoma (FTC) is the second most common cancer of the thyroid gland, accounting for up to 20% of all primary malignant tumors in iodine-replete areas. The diagnostic work-up, staging, risk stratification, management, and follow-up strategies in patients who have FTC are modeled after those of papillary thyroid carcinoma (PTC), even though FTC is more aggressive. FTC has a greater propensity for haematogenous metastasis than PTC. Furthermore, FTC is a phenotypically and genotypically heterogeneous disease. The diagnosis and identification of markers of an aggressive FTC depend on the expertise and thoroughness of pathologists during histopathological analysis. An untreated or metastatic FTC is likely to de-differentiate and become poorly differentiated or undifferentiated and resistant to standard treatment. While thyroid lobectomy is adequate for the treatment of selected patients who have low-risk FTC, it is not advisable for patients whose tumor is larger than 4 cm in diameter or has extensive extra-thyroidal extension. Lobectomy is also not adequate for tumors that have aggressive mutations. Although the prognosis for over 80% of PTC and FTC is good, nearly 20% of the tumors behave aggressively. The introduction of radiomics, pathomics, genomics, transcriptomics, metabolomics, and liquid biopsy have led to improvements in the understanding of tumorigenesis, progression, treatment response, and prognostication of thyroid cancer. The article reviews the challenges that are encountered during the diagnostic work-up, staging, risk stratification, management, and follow-up of patients who have FTC. How the application of multi-omics can strengthen decision-making during the management of follicular carcinoma is also discussed.

The expression of HDAC9 and P300 in papillary thyroid carcinoma cell line

PURPOSE

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer and accounts for 85-90% of all thyroid cancers. Metastatic differentiated thyroid cancer, radioiodine-refractory thyroid cancer, and anaplastic thyroid cancer still lack effective therapeutic options. Here, we aimed to assess HDAC9 and P300 expression in the papillary thyroid carcinoma cell line and compare them with normal thyroid cells.

METHODS

Nthy-ori-3-1, a normal thyroid cell line, and BCPAP, a PTC cell line, were cultured for 24 and 48 h and immunofluorescence staining was used to determine the levels of HDAC9 and P300 protein expression. HDAC9 paracrine release was assessed using an ELISA assay.

RESULTS

HDAC9 protein expression was higher in both cell groups at the 48th hour than at the 24th hour; however, P300 protein expression was lower in BCPAP cells at the 48th hour than at the 24th hour. In comparison to Nthy-ori-3-1, BCPAP expressed more HDAC9 and P300 proteins. HDAC9 secretion slightly increased in Nthy-ori-3-1 cells from 24 to 48 h. Furthermore, HDAC9 secretion in BCPAP cells dramatically decreased from 24 to 48 h.

CONCLUSION

Our findings revealed that the expression of HDAC9 and P300 was higher in the PTC cell line than in normal thyroid cells. This indicates that the acetylation mechanism in thyroid cancer cells is not the same as it is in healthy cells. Epigenetic studies may reveal the mechanisms underlying PTC with further analysis.

Research Progress on Epigenetics of Diabetic Cardiomyopathy in Type 2 Diabetes

Diabetic cardiomyopathy (DCM) is characterized by diastolic relaxation abnormalities in its initial stages and by clinical heart failure (HF) without dyslipidemia, hypertension, and coronary artery disease in its last stages. DCM contributes to the high mortality and morbidity rates observed in diabetic populations. Diabetes is a polygenic, heritable, and complex condition that is exacerbated by environmental factors. Recent studies have demonstrated that epigenetics directly or indirectly contribute to pathogenesis. While epigenetic mechanisms such as DNA methylation, histone modifications, and non-coding RNAs, have been recognized as key players in the pathogenesis of DCM, some of their impacts remain not well understood. Furthering our understanding of the roles played by epigenetics in DCM will provide novel avenues for DCM therapeutics and prevention strategies.

NOL4 is Downregulated and Hyper-Methylated in Papillary Thyroid Carcinoma Suggesting Its Role as a Tumor Suppressor Gene

BACKGROUND

Thyroid cancer is the fourth most common cancer in the world. Papillary thyroid carcinoma (PTC) accounts for 80% of all types of thyroid neoplasm. Epigenetic alterations such as DNA methylation are known as the main cause of different types of cancers through inactivation of tumor suppressor genes.

OBJECTIVES

In the present study, the expression and methylation of suggested gene namely nucleolar protein 4 (NOL4) in PTC in comparison to multi nodular goiter (MNG) have been studied.

METHODS

Forty-one patients with PTC and 38 patients affected by MNG were recruited. Thyroid tissues were obtained during thyroidectomy. RNA and DNA were extracted from thyroid tissues. Quantitative RT-PCR assay was performed for determining the mRNA level of NOL4 while methylation-sensitive high resolution methylation was applied for assessing the methylation status with designing six pairs primers for six regions on gene promoter which were named from NOL4 (a) to NOL4 (f).

RESULTS

Methylation assessment of 81 CpG islands in the promoter region of NOL4 gene revealed that NOL4 (f), the nearest region to the start codon, was significantly hypermethylated in PTC cases compared to MNG cases. NOL4 level in PTC cases in comparison with MNG cases were downregulated. The methylation status and mRNA level of NOL4 (f) were associated with age of diagnosis (Age of the patient at the time of diagnosis), lymph node metastasis, and advanced stages of disease.

CONCLUSIONS

These data suggested an aberrant promoter hyper-methylation of NOL4 in PTC cases may be linked with its downregulation. Therefore, NOL4 gene can be proposed as a potential tumor suppressor gene in PTC tissues.

Long noncoding RNA LINC00520 accelerates progression of papillary thyroid carcinoma by serving as a competing endogenous RNA of microRNA-577 to increase Sphk2 expression

The long noncoding RNA (lncRNA) LINC00520 is an important modulator of the oncogenicity of multiple human cancers. However, whether LINC00520 is involved in the malignancy of papillary thyroid carcinoma (PTC) has not been extensively studied until recently. Therefore, the present study aimed to detect LINC00520 expression and evaluate its clinical significance in PTC. Functional experiments were conducted to test the biological role(s) and underlying mechanisms of LINC00520 in PTC progression. Reverse transcription quantitative polymerase chain reaction was performed to detect LINC00520 expression in PTC. A series of functional experiments, including Cell Counting Kit-8 assay, flow cytometry, Transwell migration assay, and tumor xenograft assay, was employed to investigate the biological roles of LINC00520 in PTC cells. High LINC00520 expression was verified in PTC tissues and cell lines, and this high expression was associated with the unfavorable clinicopathological parameters and short overall survival of patients. Functionally, LINC00520 interference resulted in a significant decrease in PTC cell proliferation, migration, and in vitro invasion and an increase in cell apoptosis. Further, its downregulation impaired tumor growth in vivo. Mechanistically, LINC00520 functioned as a competing endogenous RNA by sponging microRNA-577 (miR-577) and thereby increasing sphingosine kinase 2 (Sphk2) expression. Rescue experiments revealed that inhibiting miR-577 or restoring Sphk2 could abrogate the effects of LINC00520 silencing on the malignant phenotypes of PTC. LINC00520 functioned as an oncogenic lncRNA in PTC, and it facilitated PTC progression by regulating the miR-577/Sphk2 axis, suggesting that the LINC00520/miR-577/Sphk2 axis is an effective target in anticancer management.

Investigation of promoter methylation of FSCN1 gene and FSCN1 protein expression in differentiated thyroid carcinomas

FSCN1 gene encodes an actin-bundling protein, FSCN1, which is involved in formation of actin-based structures that contribute to cell migration. High levels of FSCN1 expression is observed in cells with extended membranes and protrusions. Moreover, up-regulation of FSCN1 has been reported in several epithelial carcinomas. Therefore, FSCN1 is thought to play a role in cell movement and invasion. However, the mechanism behind FSCN1 up-regulation is not known. We investigated the expression of FSCN1 using immunohistochemistry. Methylation-specific PCR was adopted to analyze the methylation status of FSCN1 promoter as a potential regulatory mechanism in FSCN1 expression. The samples included papillary thyroid carcinoma, follicular thyroid carcinoma and goiter samples (controls). Methylation of FSCN1 promoter was observed in 50% of follicular, 48.6% of papillary and 60% of controls. The promoter was unmethylated in 16.7% of follicular samples, 5.7% of papillary samples and 26.7% of controls. In the remaining 33.3% of follicular and 45.7% of papillary samples as well as 13.3% of controls, both methylated and unmethylated alleles were amplified, a condition referred to as semi-methylation. The results showed that FSCN1 promoter was significantly hypomethylated in papillary cases while the methylation status was not significantly altered in follicular cases. On the other hand, FSCN1 was expressed in only nine papillary samples. Regarding protein expression and methylation status, we suggest that hypomethylation of FSCN1 promoter in papillary thyroid carcinoma does not lead to overexpression of FSCN1 and that there might be other regulatory mechanisms involved in FSCN1 up-regulation.

Cancer Stem Cells in Thyroid Tumors: From the Origin to Metastasis

Thyroid tumors are extremely heterogeneous varying from almost benign tumors with good prognosis as papillary or follicular tumors, to the undifferentiated ones with severe prognosis. Recently, several models of thyroid carcinogenesis have been described, mostly hypothesizing a major role of the thyroid cancer stem cell (TCSC) population in both cancer initiation and metastasis formation. However, the cellular origin of TCSC is still incompletely understood. Here, we review the principal epigenetic mechanisms relevant to TCSC origin and maintenance in both well-differentiated and anaplastic thyroid tumors. Specifically, we describe the alterations in DNA methylation, histone modifiers, and microRNAs (miRNAs) involved in TCSC survival, focusing on the potential of targeting aberrant epigenetic modifications for developing novel therapeutic approaches. Moreover, we discuss the bidirectional relationship between TCSCs and immune cells. The cells of innate and adaptive response can promote the TCSC-driven tumorigenesis, and conversely, TCSCs may favor the expansion of immune cells with protumorigenic functions. Finally, we evaluate the role of the tumor microenvironment and the complex cross-talk of chemokines, hormones, and cytokines in regulating thyroid tumor initiation, progression, and therapy refractoriness. The re-education of the stromal cells can be an effective strategy to fight thyroid cancer. Dissecting the genetic and epigenetic landscape of TCSCs and their interactions with tumor microenvironment cells is urgently needed to select more appropriate treatment and improve the outcome of patients affected by advanced differentiated and undifferentiated thyroid cancers.

HDAC inhibitors as antifibrotic drugs in cardiac and pulmonary fibrosis

Fibrosis usually results from dysregulated wound repair and is characterized by excessive scar tissue. It is a complex process with unclear mechanisms. Accumulating evidence indicates that epigenetic alterations, including histone acetylation, play a pivotal role in this process. Histone acetylation is governed by histone acetyltransferases (HATs) and histone deacetylases (HDACs). HDACs are enzymes that remove the acetyl groups from both histone and nonhistone proteins. Aberrant HDAC activities are observed in fibrotic diseases, including cardiac and pulmonary fibrosis. HDAC inhibitors (HDACIs) are molecules that block HDAC functions. HDACIs have been studied extensively in a variety of tumors. Currently, there are four HDACIs approved by the US Food and Drug Administration for cancer treatment yet none for fibrotic diseases. Emerging evidence from in vitro and in vivo preclinical studies has presented beneficial effects of HDACIs in preventing or reversing fibrogenesis. In this review, we summarize the latest findings of the roles of HDACs in the pathogenesis of cardiac and pulmonary fibrosis and highlight the potential applications of HDACIs in these two fibrotic diseases.