Differential expression of miRNA199b-5p as a novel biomarker for sporadic and hereditary parathyroid tumors

[Plasma miRNA expression in patients with genetically confirmed multiple endocrine neoplasia type 1 syndrome and its phenocopies]

BACKGROUND

MEN-1 is a rare autosomal dominant disease caused by mutations in MEN1 gene encoding the menin protein. This syndrome is characterized by the occurrence of parathyroid tumors, gastroenteropancreatic neuroendocrine tumors, pituitary adenomas, as well as other endocrine and non-endocrine tumors. If a patient with the MEN-1 phenotype carry no mutations in the MEN1 gene, the condition considers a phenocopy of syndrome (phMEN1). The possible cause of this changes could be changes in epigenetic regulation, particularly in microRNA expression that might affect menin signaling pathways.

AIM

to identify differently expressed circulating miRNAs in plasma in patients with genetically confirmed MEN-1 syndrome, its phenocopies and healthy controls.

MATERIALS AND METHODS

single-center, case-control study was conducted. We assessed plasma microRNA expression in patients with genetically confirmed MEN-1 (gMEN1), phMEN1 and healthy controls. Morning plasma samples were collected from fasting patients and stored at -80°C. Total RNA isolation was performed using miRNeasy Mini Kit with QIAcube. The libraries were prepared by the QIAseq miRNA Library Kit following the manufacturer. Circulating miRNA sequencing was done on Illumina NextSeq 500 (Illumina). Subsequent data processing was performed using the DESeq2 bioinformatics algorithm.

RESULTS

we enrolled 21 consecutive patients with gMEN1 and 11 patients with phMEN1, along with 12 gender matched controls. Median age of gMEN1 was 38,0 [34,0; 41,0]; in phMEN1 - 59,0 [51,0; 60,0]; control - 59,5 [51,5; 62,5]. The gMEN1 group differed in age (p<0.01) but not gender (р=0.739) or BMI (р=0.116) compared to phMEN1 and controls group, the last two groups did not differ by these parameters (p>0.05). 25 microRNA were differently expressed in groups gMEN1 and phMEN1 (21 upregulated microRNAs, 4 - downregulated). Comparison of samples from the phMEN-1 group and relatively healthy controls revealed 10 differently expressed microRNAs: 5 - upregulated; 5 - downregulated. In the gMEN-1 and control groups, 26 differently expressed microRNAs were found: 24 - upregulated; 2 - downregulated. The miRNAs most differing in expression among the groups were selected for further validation by RT-qPCR (in the groups of gMEN1 vs phMEN1 - miR-3613-5p, miR-335-5p, miR-32-5p, miR-425-3p, miR-25-5p, miR-576-5p, miR-215-5p, miR-30a-3p, miR-141-3p, miR-760, miR-501-3p; gMEN1 vs control - miR-1976, miR-144-5p miR-532-3p, miR-375; as well as in phMEN1 vs control - miR-944, miR-191-5p, miR-98-5p).

CONCLUSION

In a pilot study, we detected microRNAs that may be expressed differently between patients with gMEN-1 and phMEN-1. The results need to be validated using different measurement method with larger sample size.

Pancreatic Neuroendocrine Tumors: Signaling Pathways and Epigenetic Regulation

Pancreatic neuroendocrine tumors (PNETs) are characterized by dysregulated signaling pathways that are crucial for tumor formation and progression. The efficacy of traditional therapies is limited, particularly in the treatment of PNETs at an advanced stage. Epigenetic alterations profoundly impact the activity of signaling pathways in cancer development, offering potential opportunities for drug development. There is currently a lack of extensive research on epigenetic regulation in PNETs. To fill this gap, we first summarize major signaling events that are involved in PNET development. Then, we discuss the epigenetic regulation of these signaling pathways in the context of both PNETs and commonly occurring-and therefore more extensively studied-malignancies. Finally, we will offer a perspective on the future research direction of the PNET epigenome and its potential applications in patient care.

MicroRNA Profile Alterations in Parathyroid Carcinoma: Latest Updates and Perspectives

Simple Summary

Despite the considerable development of diagnostic tools, distinguishing between benign and malignant parathyroid tumors poses a significant diagnostic challenge. Epigenetic regulations, including noncoding microRNAs (miRNAs), have recently emerged as a new and promising source of biomarkers. MiRNAs are post-transcriptional regulators of gene expression. These tissue-specific molecules are known to be deregulated between cancer and normal cells. This review delineates changes in miRNA expression in parathyroid carcinoma (PC), advancing our understanding of PC tumorigenesis and emphasizing, at the same time, that miRNAs can be further exploited for diagnostic and therapeutic purposes.

Abstract

Parathyroid tumors are a genetically heterogenous group with a significant variability in clinical features. Due to a lack of specific signs and symptoms and uncertain histopathological criteria, parathyroid carcinomas (PCs) are challenging to diagnose, both before and after surgery. There is a great interest in searching for accurate molecular biomarkers for early detection, disease monitoring, and clinical management. Due to improvements in molecular pathology, the latest studies have reported that PC tumorigenesis is strongly linked to the epigenetic regulation of gene expression. MicroRNA (miRNA) profiling may serve as a helpful adjunct in distinguishing parathyroid adenoma (PAd) from PC and provide further insight into regulatory pathways involved in PTH release and parathyroid tumorigenesis. So far, only a few studies have attempted to show the miRNA signature for PC, and very few overlaps could be found between these relatively similar studies. A global miRNA downregulation was detected in PC compared with normal glands among differentially expressed miRNAs. This review summarizes changes in miRNA expression in PC and discusses the future research directions in this area.

Are Non-Coding RNAs Useful Biomarkers in Parathyroid Tumorigenesis?

Tumors of the parathyroid glands are common endocrine diseases almost always characterized by parathyroid hormone hypersecretion that determines the clinical manifestations of primary hyperparathyroidism, such as fatigue, kidney problems, weakness, brittle bones, and other symptoms. Most parathyroid neoplasia are benign adenomas, although rare malignant forms have been described. They are heterogeneous in terms of clinical presentation and the associated signs and symptoms overlap with those of disease and aging. Furthermore, most patients with hypercalcemia are discovered during routine blood tests for other reasons. Surgical removal is considered the main therapeutic option to cure these endocrine tumors and, therefore, innovative therapeutic approaches are actively required. Recently, a growing number of studies have suggested that alterations to the epigenetic mechanisms could play a pivotal role in parathyroid tumorigenesis. Most of the attention has been focused on non-coding RNAs (ncRNAs) (i.e., miRNAs, lncRNAs, and circRNAs) whose expression profile has been found to be deregulated in parathyroid tumors. The aim of the present paper is to give an insight into the ncRNAs involved in parathyroid tumorigenesis, which could be used in the future either as innovative diagnostic biomarkers or as therapeutic targets for the treatment of this endocrine neoplasia.

MicroRNA‑199a/b‑5p inhibits endometrial cancer cell metastasis and invasion by targeting FAM83B in the epithelial‑to‑mesenchymal transition signaling pathway

Our previous study demonstrated the role of family with sequence similarity 83, member B (FAM83B) in endometrial cancer tumorigenesis and metastasis. FAM83B is involved in epithelial‑to‑mesenchymal transition (EMT). However, the regulatory network of EMT, which promotes endometrial cancer cell metastasis, involving microRNAs (miRNAs/miRs) and FAM83B, has not been elucidated. To investigate the potential mechanism underlying miR‑199a/b‑5p in endometrial cancer, the effect of miR‑199a/b‑5p and its targeted FAM83B gene on the biological behaviour of endometrial cancer cells was assessed. The Gene Expression Omnibus dataset analysis results revealed that the expression levels of 150 miRNAs in non‑cancerous endometrial tissues were upregulated compared with those in endometrial cancer tissues. TargetScan predicted that the nucleotides 672‑679 of FAM83B 3'‑untranslated region (UTR) were the target sites of miR‑199a/b‑5p. The differentially expressed miRNAs were enriched in several Kyoto Encyclopedia of Genes and Genomes pathways. Reverse transcription‑quantitative PCR analysis revealed that the expression levels of miR‑199a/b‑5p in the endometrial non‑cancerous cell lines were significantly upregulated compared with those in the six endometrial cancer cell lines. miR‑199a/b‑5p inhibited the EMT signaling pathway by regulating the expression levels of E‑cadherin, N‑cadherin, Snail, α‑smooth muscle actin, vimentin and Twist. This suggested that miR‑199a/b‑5p inhibited endometrial cancer cell proliferation and migration through the inhibition of the EMT signaling pathway. Furthermore, the nucleotides 672‑679 of the FAM83B 3'‑UTR were demonstrated to be the binding site of miR‑199a/b‑5p. These results suggested that miR‑199a/b‑5p inhibited endometrial cancer cell proliferation and metastasis by targeting the 3'‑UTR of FAM83B, which is involved in the EMT signaling pathway.

Multiple Endocrine Neoplasia Type 1: The Potential Role of microRNAs in the Management of the Syndrome

Multiple endocrine neoplasia type 1 (MEN1) is a rare inherited tumor syndrome, characterized by the development of multiple neuroendocrine tumors (NETs) in a single patient. Major manifestations include primary hyperparathyroidism, gastro-entero-pancreatic neuroendocrine tumors, and pituitary adenomas. In addition to these main NETs, various combinations of more than 20 endocrine and non-endocrine tumors have been described in MEN1 patients. Despite advances in diagnostic techniques and treatment options, which are generally similar to those of sporadic tumors, patients with MEN1 have a poor life expectancy, and the need for targeted therapies is strongly felt. MEN1 is caused by germline heterozygous inactivating mutations of the MEN1 gene, which encodes menin, a tumor suppressor protein. The lack of a direct genotype–phenotype correlation does not permit the determination of the exact clinical course of the syndrome. One of the possible causes of this lack of association could be ascribed to epigenetic factors, including microRNAs (miRNAs), single-stranded non-coding small RNAs that negatively regulate post-transcriptional gene expression. Some miRNAs, and their deregulation, have been associated with MEN1 tumorigenesis. Recently, an extracellular class of miRNAs has also been identified (c-miRNAs); variations in their levels showed association with various human diseases, including tumors. The aim of this review is to provide a general overview on the involvement of miRNAs in MEN1 tumor development, to be used as possible targets for novel molecular therapies. The potential role of c-miRNAs as future non-invasive diagnostic and prognostic biomarkers of MEN1 will be discussed as well.

Parathyroid Tumor Microenvironment

Parathyroid tumors are the second most common endocrine neoplasia, and it is almost always associated with hypersecretion of the parathormone (PTH), involved in calcium homeostasis, causing primary hyperparathyroidism (PHPT). Parathyroid neoplasia has a stromal component particularly represented in atypical adenomatous and carcinomatous lesions. Recently, data about the features and the function of the parathyroid tumor microenvironment (TME) have been accumulated. Parathyroid TME includes heterogeneous cells: endothelial cells, myofibroblasts, lymphocytes and macrophages, and mesenchymal stem cells have been identified, each of them presenting a phenotype consistent with tumor-associated cells. Parathyroid tumors overexpress proangiogenic molecules including vascular endothelial growth factor (VEGF-A), fibroblast growth factor-2 (FGF-2), and angiopoietins that promote both recruitment and proliferation of endothelial cell precursors, thus resulting in a microvessel density higher than that detected in normal parathyroid glands. Moreover, parathyroid tumor endocrine cells operate multifaceted interactions with stromal cells, partly mediated by the CXCL12/CXCR4 pathway, while, at present, the immune landscape of parathyroid tumors has just begun to be investigated. Studies about TME in parathyroid adenomas provide an example of the role of TME in benign tumors, whose molecular mechanisms and functions comprehension are limited.

Usefulness of serum microRNA as a predictive marker of recurrence and prognosis in biliary tract cancer after radical surgery

Biliary tract cancer (BTC) is an aggressive type of malignant tumour. Even after radical resection, the risk of recurrence is still high, resulting in a poor prognosis. Here, we investigated the usefulness of serum miRNAs as predictive markers of recurrence and prognosis for patients with BTC after radical surgery using 66 serum samples that were collected at three time points from 22 patients with BTC who underwent radical surgery. Using microarray analysis, we successfully identified six specific miRNAs (miR-1225-3p, miR-1234-3p, miR1260b, miR-1470, miR-6834-3p, and miR-6875-5p) associated with recurrence and prognosis of BTC after radical surgery. In addition, using a combination of these miRNAs, we developed a recurrence predictive index to predict recurrence in patients with BTC after operation with high accuracy. Patients having higher index scores (≥ cut-off) had significantly worse recurrence-free survival (RFS) and overall survival (OS) than those with lower index scores (<cut-off). Furthermore, the index was an independent factor related to RFS and OS by univariate and multivariate analyses using a Cox hazard proportional model. Overall, our results provided compelling evidence for the potential usefulness of specific serum miRNAs as effective predictive tools for recurrence and prognosis in patients with BTC who underwent radical surgery.