Noncoding RNAs in endocrine malignancy

Circular RNAs in cancer

Circular RNA (circRNA), a subtype of noncoding RNA, has emerged as a significant focus in RNA research due to its distinctive covalently closed loop structure. CircRNAs play pivotal roles in diverse physiological and pathological processes, functioning through mechanisms such as miRNAs or proteins sponging, regulation of splicing and gene expression, and serving as translation templates, particularly in the context of various cancers. The hallmarks of cancer comprise functional capabilities acquired during carcinogenesis and tumor progression, providing a conceptual framework that elucidates the nature of the malignant transformation. Although numerous studies have elucidated the role of circRNAs in the hallmarks of cancers, their functions in the development of chemoradiotherapy resistance remain unexplored and the clinical applications of circRNA-based translational therapeutics are still in their infancy. This review provides a comprehensive overview of circRNAs, covering their biogenesis, unique characteristics, functions, and turnover mechanisms. We also summarize the involvement of circRNAs in cancer hallmarks and their clinical relevance as biomarkers and therapeutic targets, especially in thyroid cancer (TC). Considering the potential of circRNAs as biomarkers and the fascination of circRNA-based therapeutics, the "Ying-Yang" dynamic regulations of circRNAs in TC warrant vastly dedicated investigations.

Possible role of miRNAs in pheochromocytoma pathology - Signaling pathways interaction

Pheochromocytoma (PCC) is a type of neuroendocrine tumor that originates from adrenal medulla or extra-adrenal chromaffin cells and results in the production of catecholamine. Paroxysmal hypertension and cardiovascular crises were among the clinical signs experienced by people with PCC. Five-year survival of advanced-stage PCC is just around 40% despite the identification of various molecular-level fundamentals implicated in these pathogenic pathways. MicroRNAs (miRNAs, miRs) are a type of short, non-coding RNA (ncRNA) that attach to the 3'-UTR of a target mRNA, causing translational inhibition or mRNA degradation. Evidence is mounting that miRNA dysregulation plays a role in the development, progression, and treatment of cancers like PCC. Hence, this study employs a comprehensive and expedited survey to elucidate the potential role of miRNAs in the development of PCC, surpassing their association with survival rates and treatment options in this particular malignancy.

A novel signature to predict thyroid cancer prognosis and immune landscape using immune-related LncRNA pairs

BACKGROUND

Thyroid cancer (TC) is the most common endocrine malignancy worldwide. The incidence of TC is high and increasing worldwide due to continuous improvements in diagnostic technology. Therefore, identifying accurate prognostic predictions to stratify TC patients is important.

METHODS

Raw data were downloaded from the TCGA database, and pairwise comparisons were applied to identify differentially expressed immune-related lncRNA (DEirlncRNA) pairs. Then, we used univariate Cox regression analysis and a modified Lasso algorithm on these pairs to construct a risk assessment model for TC. We further used qRT‒PCR analysis to validate the expression levels of irlncRNAs in the model. Next, TC patients were assigned to high- and low-risk groups based on the optimal cutoff score of the model for the 1-year ROC curve. We evaluated the signature in terms of prognostic independence, predictive value, immune cell infiltration, immune status, ICI-related molecules, and small-molecule inhibitor efficacy.

RESULTS

We identified 14 DEirlncRNA pairs as the novel predictive signature. In addition, the qRT‒PCR results were consistent with the bioinformatics results obtained from the TCGA dataset. The high-risk group had a significantly poorer prognosis than the low-risk group. Cox regression analysis revealed that this immune-related signature could predict prognosis independently and reliably for TC. With the CIBERSORT algorithm, we found an association between the signature and immune cell infiltration. Additionally, immune status was significantly higher in low-risk groups. Several immune checkpoint inhibitor (ICI)-related molecules, such as PD-1 and PD-L1, showed a negative correlation with the high-risk group. We further discovered that our new signature was correlated with the clinical response to small-molecule inhibitors, such as sunitinib.

CONCLUSIONS

We have constructed a prognostic immune-related lncRNA signature that can predict TC patient survival without considering the technical bias of different platforms, and this signature also sheds light on TC's overall prognosis and novel clinical treatments, such as ICB therapy and small molecular inhibitors.

Circular RNAs and thyroid cancer: closed molecules, open possibilities

Thyroid neoplasms requiring differential diagnosis between thyroid cancer and benign tumors can be detected in more than half of the healthy population. A generally accepted method that allows assessing the risk of malignant potential and determining the indications for surgical treatment of thyroid tumor is a fine-needle aspiration biopsy followed by a cytological examination. Nevertheless, in patients with indeterminate categories of cytological conclusions according to Bethesda system, the positive predictive value of the cytology result is significantly lower than desired and often leads to unjustified surgical treatment. In this regard, the search for alternative diagnostic solutions continues. Circular RNAs are a group of non-coding RNAs distinguished by a closed structure formed by covalent bonding of the nucleotide chain ends. Recent studies allow us to conclude that many different circular RNAs are involved in processes mediating oncogenesis in the thyroid gland, and their altered expression in tissue, blood, and exosomes of plasma may be a characteristic sign of thyroid cancer and certain clinicopathological features of its course. The purpose of this review is to analyze the accumulated data on the association of various circular RNAs with thyroid cancer and to discuss possible ways to improve the diagnosis and treatment of the disease based on the assessment of the expression of these molecules.

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.

Long non-coding RNA signatures as predictors of prognosis in thyroid cancer: a narrative review

Thyroid cancer (TC) is the most common endocrine malignancy, with high incidence rates in recent decades. Most TC cases have good prognoses, but a high risk of recurrence and metastases poses challenges, especially for patients with high-risk factors. Currently used prognostic markers for TC involve a combination of genetic factors and overexpressed proteins. Long non-coding RNAs (lncRNAs) regulate several integral biologic processes by playing key roles in the transcription of several downstream targets maintaining cellular behavior. Prior studies have revealed that lncRNAs promote tumor cell proliferation, invasion, metastasis, and angiogenesis, making them important targets for therapeutic intervention in cancer. While the exact molecular mechanisms underlying the role of lncRNAs in modulating TC progression and recurrence is still unclear, it is important to note that some lncRNAs are upregulated in certain cancers, while others are downregulated. In the present study, we review several key lncRNAs, their association with cancer progression, and the important roles they may play as tumor suppressors or tumor promoters in tumorigenesis. We discuss the potential mechanisms of lncRNA-mediated pathogenesis that can be targeted for the treatment of TC, the existing and potential benefits of using lncRNAs as diagnostic and prognostic measures for cancer detection, and tumor burden in patients.

Biomarkers for Pancreatic Neuroendocrine Neoplasms (PanNENs) Management-An Updated Review

Pancreatic neuroendocrine tumors (PanNENs) are rare sporadic cancers or develop as part of hereditary syndromes. PanNENs can be both functioning and non-functioning based on whether they produce bioactive peptides. Some PanNENs are well differentiated while others-poorly. Symptoms, thus, depend on both oncological and hormonal causes. PanNEN diagnosis and treatment benefit from and in some instances are guided by biomarker monitoring. However, plasmatic monoanalytes are only suggestive of PanNEN pathological status and their positivity is typically followed by deepen diagnostic analyses through imaging techniques. There is a strong need for new biomarkers and follow-up modalities aimed to improve the outcome of PanNEN patients. Liquid biopsy follow-up, i.e., sequential analysis on tumor biomarkers in body fluids offers a great potential, that need to be substantiated by additional studies focusing on the specific markers and the timing of the analyses. This review provides the most updated panorama on PanNEN biomarkers.

Lcn2-derived Circular RNA (hsa_circ_0088732) Inhibits Cell Apoptosis and Promotes EMT in Glioma via the miR-661/RAB3D Axis

Background: Glioma is the most common malignant tumor of the central nervous system, and often displays invasive growth. Recently, circular RNA (circRNA), which is a novel non-coding type of RNA, has been shown to play a vital role in glioma tumorigenesis. However, the functions and mechanism of lipocalin-2 (Lcn2)-derived circular RNA (hsa_circ_0088732) in glioma progression remain unclear.

Methods: We evaluated hsa_circ_0088732 expression by fluorescence in situ hybridization (FISH), Sanger sequencing, and PCR assays. Cell apoptosis was evaluated by flow cytometry and Hoechst 33258 staining. Transwell migration and invasion assays were performed to measure cell metastasis and viability. In addition, the target miRNA of hsa_circ_0088732 and the target gene of miR-661 were predicted by a bioinformatics analysis, and the interactions were verified by dual-luciferase reporter assays. RAB3D expression was analyzed by an immunochemistry assay, and E-cadherin, N-cadherin, and vimentin protein expression were examined by western blot assays. A mouse xenograft model was developed and used to analyze the effects of hsa_circ_0088732 on glioma growth in vivo.

Results: We verified that hsa_circ_0088732 is circular and highly expressed in glioma tissues. Knockdown of hsa_circ_0088732 induced glioma cell apoptosis and inhibited glioma cell migration, invasion, and epithelial-mesenchymal transition (EMT). We found that hsa_circ_0088732 negatively regulated miR-661 by targeting miR-661, and RAB3D was a target gene of miR-661. In addition, inhibition of miR-661 promoted glioma cell metastasis and suppressed cell apoptosis. Knockdown of RAB3D induced cell apoptosis and suppressed cell metastasis. Moreover, hsa_circ_0088732 accelerated glioma progression through its effects on the miR-661/RAB3D axis. Finally, results from a mouse xenograft model confirmed that knockdown of hsa_circ_0088732 induced miR-661 expression, resulting in suppression of RAB3D expression and inhibition of tumor growth in vivo.

Conclusion: We demonstrated that hsa_circ_0088732 facilitated glioma progression by sponging miR-661 to increase RAB3D expression. This study provides a theoretical basis for understanding the development and occurrence of glioma, as well as for the development of targeted drugs.

Long non-coding RNA KDM5B anti-sense RNA 1 enhances tumor progression in non-small cell lung cancer

BACKGROUND

The long non-coding RNAs (lncRNAs) have been shown as a novel class of transcripts with no protein coding functions. LncRNAs can play diverse roles in cancer cell proliferation, differentiation, metastasis, and apoptosis. However, the exact contributions of lncRNA KDM5B anti-sense RNA 1 (KDM5BAS1) to non-small cell lung cancer (NSCLC) remain poorly understood.

METHODS

In current study, we have unraveled a novel function of KDM5BAS1 in NSCLC.

RESULTS

We found that KDM5BAS1 was significantly overexpressed in tumor specimens and selected cancerous cell lines. Meanwhile, higher KDM5BAS1 expression predicted poor overall survival. Increased KDM5BAS1 expression can promote proliferation or migration and inhibit apoptosis in H1838 and H1299 cells. Furthermore, knocking down of KDM5BAS1 levels can also reduce tumor growth in in vivo implantation experiments. Overexpression of KDM5BAS1 also decreased the caspase-3 immunostaining but enhanced Ki-67 staining.

CONCLUSION

Taken together, our findings indicated that KDM5BAS1 might play an oncogenic role in NSCLC and provided clues into pharmacological intervention targeting KDM5BAS1.

Parathyroid Neoplasms: Immunohistochemical Characterization and Long Noncoding RNA (lncRNA) Expression

Parathyroid adenomas are slow growing benign neoplasms associated with hypercalcemia, while atypical parathyroid adenomas and parathyroid carcinomas are uncommon tumors and their histologic features may overlap with parathyroid adenomas. LncRNAs participate in transcription and in epigenetic or post-transcriptional regulation of gene expression, and probably contribute to carcinogenesis. We analyzed a group of normal, hyperplastic, and neoplastic parathyroid lesions to determine the best immunohistochemical markers to characterize these lesions and to determine the role of selected lncRNAs in tumor progression. A tissue microarray consisting of 111 cases of normal parathyroid (n = 14), primary hyperplasia (n = 15), secondary hyperplasia (n = 10), tertiary hyperplasia (n = 11), adenomas (n = 50), atypical adenomas (n = 7), and carcinomas (n = 4) was used. Immunohistochemical staining with antibodies against chromogranin A, synaptophysin, parathyroid hormone, and insulinoma-associated protein 1(INSM1) was used. Expression of lncRNAs including metastasis-associated lung adenocarcinoma transcript one (MALAT1), HOX transcript antisense intergenic RNA (HOTAIR), and long intergenic non-protein coding regulator of reprograming (Linc-ROR or ROR) was also analyzed by in situ hybridization and RT-PCR. All of the parathyroid tissues were positive for parathyroid hormone, while most cases were positive for chromogranin A (98%). Synaptophysin was expressed in only 12 cases (11%) and INMS1 was negative in all cases. ROR was significantly downregulated during progression from normal, hyperplastic, and adenomatous parathyroid to parathyroid carcinomas. These results show that parathyroid hormone and chromogranin A are useful markers for parathyroid neoplasms, while synaptophysin and INSM1 are not very sensitive broad-spectrum markers for these neoplasms. LincRNA ROR may function as a tumor suppressor during parathyroid tumor progression.

FOXK transcription factors: Regulation and critical role in cancer

Growing evidence suggests that alterations of gene expression including expression and activities of transcription factors are closely associated with carcinogenesis. Forkhead Box Class K (FOXK) proteins, FOXK1 and FOXK2, are a family of evolutionarily conserved transcriptional factors, which have recently been recognized as key transcriptional regulators involved in many types of cancer. Members of the FOXK family mediate a wide spectrum of biological processes, including cell proliferation, differentiation, apoptosis, autophagy, cell cycle progression, DNA damage and tumorigenesis. Therefore, the deregulation of FOXKs can affect the cell fate and they promote tumorigenesis as well as cancer progression. The mechanisms of FOXKs regulation including post-translational modifications (PTMs), microRNAs (miRNAs) and protein-protein interactions are well demonstrated. However, the detailed mechanisms of FOXKs activation and deregulation in cancer progression are still inconclusive. In this review, we summarize the regulatory mechanisms of FOXKs expression and activity, and their role in the development and progression of cancer. We have discussed whether FOXKs act as tumor suppressors/oncoproteins in tumor cells and their therapeutic applications in malignant diseases are also discussed. This review may assist in designing experimental studies involving FOXKs and it would strength the therapeutic potential of FOXKs as targets for cancers.

miR-375 mediates the CRF signaling pathway to regulate catecholamine biosynthesis by targeting Sp1 in porcine adrenal gland

Corticotropin-releasing-factor (CRF) is a key regulator of catecholamines (CATs) biosynthesis in the adrenal gland. Furthermore, miR-375 has been confirmed to be localized in the mouse adrenal gland. However, the relationships between miR-375 and CRF in regulating CATs biosynthesis remain to be established. This study was designed to investigate the relationship between CRF and miR-375 in the regulation of CATs biosynthesis in the porcine adrenal gland. Eight adult female pigs (four controls; four injected intracerebroventricularly with 50 μg of CRF) were used for the in vivo experiments in this study. The results showed that miR-375 was exclusively localized in porcine adrenal medullary cells. Functional studies showed that miR-375 negatively regulated CATs synthesis in primary cells by affecting the expression of the CATs synthetases tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), and phenylethanolamine-N-methyltransferase (PNMT). CRF up-regulated the expression of CATs synthetase in primary adrenal medullary cells under basal conditions and upon endogenous miR-375 inhibition; the enhanced effects vanished when cellular miR-375 was overexpressed by transfecting miR-375-mic. CRF decreased the expression of miR-375 both in vivo and in vitro. Our in vitro results showed that CRF significantly decreased the expression of miR-375, perhaps by binding to CRFR1. miR-375 functions by directly binding to the 3'-UTR region of specificity protein 1 (Sp1), which is involved in regulating Th and Dbh expression. These data collectively indicate that miR-375 plays an important role in regulating CATs synthesis and mediates the CRF signaling pathway in porcine adrenal medullary cells.

Suppression of long non-coding RNA TNRC6C-AS1 protects against thyroid carcinoma through DNA demethylation of STK4 via the Hippo signalling pathway

Objectives

Thyroid carcinoma (TC) represents a malignant neoplasm affecting the thyroid. Current treatment strategies include the removal of part of the thyroid; however, this approach is associated with a significant risk of developing hypothyroidism. In order to adequately understand the expression profiles of TNRC6C‐AS1 and STK4 and their potential functions in TC, an investigation into their involvement with Hippo signalling pathway and the mechanism by which they influence TC apoptosis and autophagy were conducted.

Methods

A microarray analysis was performed to screen differentially expressed lncRNAs associated with TC. TC cells were employed to evaluate the role of TNRC6C‐AS1 by over‐expression or silencing means. The interaction of TNRC6C‐AS1 with methylation of STK4 promoter was evaluated to elucidate its ability to elicit autophagy, proliferation and apoptosis.

Results

TNRC6C‐AS1 was up‐regulated while STK4 was down‐regulated, where methylation level was elevated. STK4 was verified as a target gene of TNRC6C‐AS1, which was enriched by methyltransferase. Methyltransferase’s binding to STK4 increased expression of its promoter. Over‐expressed TNRC6C‐AS1 inhibited STK4 by promoting STK4 methylation and reducing the total protein levels of MST1 and LATS1/2. The phosphorylation of YAP1 phosphorylation was decreased, which resulted in the promotion of SW579 cell proliferation and tumorigenicity.

Conclusion

Based on our observations, we subsequently confirmed the anti‐proliferative, pro‐apoptotic and pro‐autophagy capabilities of TNRC6C‐AS1 through STK4 methylation via the Hippo signalling pathway in TC.

The long noncoding RNA ST7-AS1 promotes laryngeal squamous cell carcinoma by stabilizing CARM1

The laryngeal squamous cell carcinoma (LSCC) represents a malignant cancer and contributes largely to head and neck tumorigenesis. The molecular mechanisms for LSCC progression are poorly understood. In current work, we identified long non-coding RNA (lncRNA) termed suppressor of tumorigenicity 7 antisense RNA 1 (ST7-AS1) as an oncogenic factor in LSCC. ST7-AS1 is frequently overexpressed in LSCC tissues and cell lines. ST7-AS1 is required for the malignancy of LSCC cells through migration, tumor sphere formation assay and in vivo implantation. Mechanistically, ST7-AS1 could interact with CARM1, a well characterized protein arginine methyltransferase and protect CARM1 from ubiquitin-dependent degradation. CARM1 can methylate Sox-2, a pluripotent transcription factor. Thus, ST7-AS1 might mediate its oncogenic effect by signaling through CARM1-Sox-2 axis to enhance Sox-2 self-association and transactivation activity. Collectively, we have unraveled a ST7-AS1/CARM1/Sox-2 signaling axis in LSCC and may have created novel interconnections between noncoding RNAs and cancer development.

Dictating genomic destiny: Epigenetic regulation of pancreatic neuroendocrine tumours

Pancreatic neuroendocrine tumours are a diverse group of neoplasms with an increasingly well-defined genomic basis. Despite this, much of what drives this disease is still unknown and epigenetic influences represent the next tier of gene, and hence disease modifiers that are of unquestionable importance. Moreover, they are of arguably more significance than the genes themselves given their malleable nature and potential to be exploited for not only diagnosis and prognosis, but also therapy. This review summarises what is known regarding the key epigenetic modifiers of disease through the domains of diagnosis, prognosis and treatment.

LncRNA TNRC6C-AS1 regulates UNC5B in thyroid cancer to influence cell proliferation, migration, and invasion as a competing endogenous RNA of miR-129-5p

To investigate the biological functions and regulatory mechanism of lncRNA TNRC6C-AS1 in thyroid cancer (TC). TNRC6C-AS1, miR-129-5p, and UNC5B expression levels were investigated by qRT-PCR and Western blot. CCK-8 assay was conducted to determine cell proliferation, while transwell assay was for inspection of cell migration and invasion. Through bioinformatic analysis, the interactions among TNRC6C-AS1, miR-129-5p, and UNC5B were predicted. Dual luciferase reporter gene assay and RNA pull-down assay confirmed the predicted target relationships. Tumor xenograft assay was applied to inspect the effect of TNRC6C-AS1 downregulation on TC development in vivo. TNRC6C-AS1 and UNC5B were overexpressed, while miR-129-5p was underexpressed in TC tissues and cells. TNRC6C-AS1/UNC5B downregulation and miR-129-5p overexpression could suppress proliferation, migration, and invasion of TC cells as well as inhibit tumorigenesis in vivo. MiR-129-5p targeted TNRC6C-AS1 and UNC5B in TC cells; and UNC5B expression was downregulated by knocking down TNRC6C-AS1, which competitively bound with miR-129-5p. Downregulation of TNRC6C-AS1 restrained TC development by knocking down UNC5B through upregulating the expression of miR-129-5p.

Long noncoding RNAs: emerging players in thyroid cancer pathogenesis

Thyroid cancer continues to be the most common malignancy of endocrine glands. The incidence of thyroid cancer has risen significantly over the past 4 decades and has emerged as a major health issue. In recent years, significant progress has been achieved in our understanding of the molecular mechanisms of thyroid carcinogenesis, resulting in significant diagnostic, prognostic and therapeutic implications; yet, it has not reached a satisfactory level. Identifying novel molecular therapeutic targets and molecules for diagnosis and prognosis is expected to advance the overall management of this common malignancy. Long noncoding RNAs (lncRNAs) are implicated in the regulation of various key cellular genes involved in cell differentiation, proliferation, cell cycle, apoptosis, migration and invasion mainly through modulation of gene expression. Recent studies have established that lncRNAs are deregulated in thyroid cancer. In this review, we discuss extensively the tumor-suppressive (for example, LINC00271, MEG3, NAMA, PTCSC1/2/3, etc.) and oncogenic (for example, ANRIL, FAL1, H19, PVT1, etc.) roles of various lncRNAs and their possible disease associations implicated in thyroid carcinogenesis. We briefly summarize the strategies and mechanisms of lncRNA-targeting agents. We also describe the potential role of lncRNAs as prospective novel therapeutic targets, and diagnostic and prognostic markers in thyroid cancer.

Long non-coding RNA in pancreatic adenocarcinoma and pancreatic neuroendocrine tumors

Interest in non-coding regions of DNA has been increasing since the mapping of the human genome revealed that human DNA contains far fewer genes encoding proteins than previously expected. However, analysis of the derivatives of DNA transcription (transcriptomics) revealed that the majority of the genetic material is transcribed into non-coding RNA (ncRNA), indicating that these molecules probably provide the functional diversity and complexity of the physiology of the human body that cannot be attributed to the proteins. Of these ncRNA, long ncRNA (lncRNA) have a length greater than 200 nucleotides and share many common components with the coding messenger RNA (mRNA): They are transcribed by RNA polymerase II, comprised of multiple exons and subjected to normal RNA splicing giving RNA products of several kilobases. Scientific data reveal the regulatory role of lncRNA in the control of gene expression during cell development and homeostasis. However, to date, very few lncRNAs have been characterized in depth, and lncRNAs are thought to have a wide range of functions in cellular and developmental processes. These molecules will have the possibility to be used as biomarkers and contribute to the development of targeted therapies. Concerning pancreatic cancer, there are limited data in the literature that correlate the growth of these tumors with deregulation of various lncRNA. We herein review the literature regarding the role of lncRNA as a diagnostic and prognostic biomarker and possible therapeutic target in the neoplasms of the pancreas, particularly pancreatic adenocarcinoma and pancreatic neuroendocrine tumors.

Profiling of metastatic small intestine neuroendocrine tumors reveals characteristic miRNAs detectable in plasma

Background

Current diagnostic and prognostic blood-based biomarkers for neuroendocrine tumors are limited. MiRNAs have tumor-specific expression patterns, are relatively stable, and can be measured in patient blood specimens. We performed a multi-stage study to identify and validate characteristic circulating miRNAs in patients with metastatic small intestine neuroendocrine tumors, and to assess associations between miRNA levels and survival.

Methods

Using a 742-miRNA panel, we identified candidate miRNAs similarly expressed in 19 small intestine neuroendocrine tumors and matched plasma samples. We refined our panel in an independent cohort of plasma samples from 40 patients with metastatic small intestine NET and 40 controls, and then validated this panel in a second, large cohort of 120 patients with metastatic small intestine NET and 120 independent controls.

Results

miRNA profiling of 19 matched small intestine neuroendocrine tumors and matched plasma samples revealed 31 candidate miRNAs similarly expressed in both tissue and plasma. We evaluated expression of these 31 candidate miRNAs in 40 independent cases and 40 normal controls, and identified 4 miRNAs (miR-21-5p, miR-22-3p, miR-29b-3p, and miR-150-5p) that were differently expressed in cases and controls (p<0.05). We validated these 4 miRNAs in a separate, larger panel of 120 cases and 120 controls. We confirmed that high circulating levels of miR-22-3p (p<0.0001), high levels of miR 21-5p, and low levels of miR-150-5p (p=0.027) were associated with the presence of metastatic small intestine NET. While levels of 29b-3p were lower in cases than in controls in both the initial cohort and the validation cohort, the difference in the validation cohort did not reach statistical significance. We further found that high levels of circulating miR-21-5p, high levels of circulating miR-22-3p and low levels of circulating miR-150-5p were each independently associated with shorter overall survival. A combined analysis using all three markers was highly prognostic for survival (HR 0.47, 95% CI 0.27-0.82).

Conclusions

Our study suggests that elevated circulating levels of miR-21-5p and miR-22-3p and low levels of miR-150-5p are characteristic in patients with metastatic small intestine neuroendocrine tumors, and further suggests that levels of these miRNAs are associated with overall survival. These observations provide the basis for further validation studies, as well as studies to assess the biological function of these miRNAs in small intestine neuroendocrine tumors.

A molecular conundrum involving hypothalamic responses to and roles of long non-coding RNAs following food deprivation

Long non-coding RNAs (lncRNAs) are one of most poorly understood RNA classes in the mammalian transcriptome. However, they are emerging as important players in transcriptional regulation, especially within the complexity of the nervous system. This review summarizes the known information about lncRNAs, and their roles in endocrine processes, as well as the lesser-known information about lncRNAs in the brain, and in the neuroendocrine hypothalamus. A "call-to-action" is presented for researchers to use archival transcriptome data to characterize differentially expressed lncRNA species within the hypothalamus. In accordance, we analyze for differential-expression of lncRNA between normal mice and mice with a targeted deletion of the nescient helix-loop-helix 2 gene, and between C57Bl/6 and 129Sv/J mice. Finally, strategies and approaches for researchers to analyze their own datasets or those on the NCBI GEO datasets repository are provided, in hopes that future studies will reveal many new roles for lncRNAs in hypothalamic physiological responses, solving this so-called "molecular conundrum" once and for all.

Overexpression of long non-coding RNA NR_036575.1 contributes to the proliferation and migration of papillary thyroid cancer

Current evidence suggests that the human genome produces a large number of non-coding RNAs, including microRNAs and long non-coding RNAs (lncRNAs). Generally, lncRNAs are defined as RNA transcripts longer than 200 nucleotides that are not transcribed into proteins. In recent years, lncRNAs have been reported to play oncogenic roles in tumourigenesis. However, minimal research has been performed on the expression and clinicopathological significance of lncRNAs in papillary thyroid cancer (PTC). In the present study, we investigated not only the expression and clinicopathological significance of a novel lncRNA, NR_036575.1, in PTC tissues and adjacent non-cancerous tissues but also its potential function in TPC1 cells. The expression levels of the lncRNA NR_036575.1 in 83 pairs of PTC tissues and adjacent non-cancerous tissues were detected via quantitative real-time polymerase chain reaction. The relationships between the expression levels and clinicopathological characteristics of the lncRNA NR_036575.1 were analysed. In addition, we established two receiver operating characteristic (ROC) curves to assess the diagnostic value of NR_036575.1 expression. Cell Counting Kit-8 and transwell assays were used to assess cell proliferation and migration, respectively. The expression levels of the lncRNA NR_036575.1 were significantly higher in PTC tissues than in adjacent non-cancerous tissues. High NR_036575.1 expression was associated with extrathyroidal extension (ETE) (P = 0.011) and tumour size (P = 0.006). The ROC curves indicated that NR_036575.1 could potentially serve as a biomarker for identifying PTC and related, non-cancerous diseases (sensitivity, 80.7 %; specificity, 88 %), as well as for differentiating between PTC with or without ETE (sensitivity, 57.8 %; specificity, 86.7 %). NR_036575.1 knock-down significantly inhibited the proliferation and migration of TPC1 cells. Our findings are the first to describe lncRNA NR_036575.1 overexpression in PTC. NR_036575.1 expression was associated with both ETE and tumour size. In addition, NR_036575.1 modulation could regulate TPC1 cell proliferation and migration. The results of our study suggest that NR_036575.1 could be applied as a potential biomarker and a novel therapeutic target for PTC patients.

ENDOCRINE TUMOURS: Genetic predictors of thyroid cancer outcome

Genetic predictors of outcome are reviewed in the context of a disease--cancer--that can be (too) simplistically described as a 'successful, invasive clone of our own tissues'. Context has many faces that determine a thyroid cancer patient's outcome beyond the influence of genetic markers. There is also plenty of evidence on the prognostic meaning of the interplay between genetics and context/microenvironment factors (encapsulation, degree of invasion, staging, etc.). This review addresses only genetic alterations detected by molecular methods in surgically resected specimens, thus ruling out immunohistochemistry and (F)ISH, despite their crucial relevance as topographically oriented methods. For the sake of the discussion, well-differentiated carcinomas were divided into two main morphologic types: papillary carcinoma (classic and most variants) displaying BRAFV600E mutations and RET/papillary thyroid carcinoma rearrangements and the group of follicular patterned carcinomas that encompasses follicular carcinoma and the encapsulated form of follicular variant of papillary carcinoma, displaying RAS mutations and PAX8/PPARγ rearrangement. TERT promoter mutations have been recently described (and associated with distant metastases and reduced survival) in papillary and follicular carcinomas, as well as in poorly differentiated and undifferentiated carcinoma. TP53 mutations, previously thought to be restricted to less differentiated carcinomas, were also detected in papillary and follicular carcinoma and found to carry a guarded prognosis. Besides their putative importance for targeted therapies, the prognostic meaning of such mutations is discussed per se and in the setting of concurrent BRAF mutation.

Non-coding RNAs: Functions and applications in endocrine-related cancer

A significant fraction of the human genome is transcribed as non-coding RNAs (ncRNAs). This non-coding transcriptome has challenged the notion of the central dogma and its involvement in transcriptional and post-transcriptional regulation of gene expression is well established. Interestingly, several ncRNAs are dysregulated in cancer and current non-coding transcriptome research aims to use our increasing knowledge of these ncRNAs for the development of cancer biomarkers and anti-cancer drugs. In endocrine-related cancers, for which survival rates can be relatively low, there is a need for such advancements. In this review, we aimed to summarize the roles and clinical implications of recently discovered ncRNAs, including long ncRNAs, PIWI-interacting RNAs, tRNA- and Y RNA-derived ncRNAs, and small nucleolar RNAs, in endocrine-related cancers affecting both sexes. We focus on recent studies highlighting discoveries in ncRNA biology and expression in cancer, and conclude with a discussion on the challenges and future directions, including clinical application. ncRNAs show great promise as diagnostic tools and therapeutic targets, but further work is necessary to realize the potential of these unconventional transcripts.

Molecular genetic findings in small bowel neuroendocrine neoplasms: a review of the literature

Small bowel neuroendocrine neoplasms (SBNEN) are the most common small bowel tumor and have an increasing incidence. Despite many treatment options, therapeutic strategy remains a key clinical challenge due to the paucity of large-scale, randomized controlled trials. The heterogeneity of SBNEN coupled with a lack of detailed information about the tumor biology, impedes patient stratification into groups based on tumor phenotypes or treatment response. More detailed analysis of the genetic and epigenetic characteristics of SBNEN, will allow treatment to move toward a more personalized medicine approach through the identification of novel biomarkers and therapeutic targets, with the aim to increase survival.

Long non-coding RNAs as regulators of the endocrine system

Long non-coding RNAs (lncRNAs) are a large and diverse group of RNAs that are often lineage-specific and that regulate multiple biological functions. Many are nuclear and are essential parts of ribonucleoprotein complexes that modify chromatin segments and establish active or repressive chromatin states; others are cytosolic and regulate the stability of mRNA or act as microRNA sponges. This Review summarizes the current knowledge of lncRNAs as regulators of the endocrine system, with a focus on the identification and mode of action of several endocrine-important lncRNAs. We highlight lncRNAs that have a role in the development and function of pancreatic β cells, white and brown adipose tissue, and other endocrine organs, and discuss the involvement of these molecules in endocrine dysfunction (for example, diabetes mellitus). We also address the associations of lncRNAs with nuclear receptors involved in major hormonal signalling pathways, such as estrogen and androgen receptors, and the relevance of these associations in certain endocrine cancers.

MiR-25 promotes ovarian cancer proliferation and motility by targeting LATS2

Ovarian cancer (OC) is a major cancer-related mortality among women. Recent studies suggest that many microRNAs (miRNAs) were dysregulated and involved in tumorigenesis of OC. The present study investigated the role of miR-25 in the development and progression of OC. The expression of miR-25 was increased in OC tissues and cell lines. Inhibition of miR-25 remarkably suppressed proliferation, migration, and invasion of OC cells. Large tumor suppressor 2 (LATS2), a tumor suppressor, was confirmed to be a direct target of miR-25 in OC cells. Moreover, restoration of LATS2 significantly attenuated the oncogenic effects of miR-25. Together, our data suggest an oncogenic role of miR-25 in OC and a potentially novel diagnostic and therapeutic target for OC treatment.