BRAF-Activated Long Noncoding RNA Modulates Papillary Thyroid Carcinoma Cell Proliferation through Regulating Thyroid Stimulating Hormone Receptor

BANCR: a cancer-related long non-coding RNA

Long non-coding RNAs (lncRNAs) are a group of non-protein-coding RNAs with more than 200 nucleotides in length. lncRNAs are involved in diverse biological processes, including development, cell proliferation and differentiation. Emerging evidences also suggest that lncRNAs may participate in cancer development by functioning as tumor suppressors and oncogenes. BRAF-activated non-coding RNA (BANCR) was first identified as an oncogene in melanoma. Later studies demonstrated that BANCR was frequently deregulated in human cancers, including lung cancer, gastric cancer, colorectal cancer, thyroid cancer and osteosarcoma. Nevertheless, the direction of deregulation was tissue-specific in which BANCR could as an oncogene or tumor-suppressor gene. In this review, we compile current evidences concerning the functional roles and molecular mechanisms of BANCR in tumor development.

Luteolin suppresses tumor progression through lncRNA BANCR and its downstream TSHR/CCND1 signaling in thyroid carcinoma

The flavonoid luteolin is a natural antioxidant that usually occurs in its glycosylated form in many green vegetables, and has shown anticancer effects against various cancers. However, the potential tumor-suppressive role of luteolin in thyroid carcinoma and its underlying mechanism remain largely unknown. In current study, SBR assay, clone formation assay were employed to evaluate the effects of luteolin on thyroid cancer. We found that luteolin significantly inhibits thyroid cancer growth. The further mechanisms of its anticancer activity were analyzed by flow cytometry, quantitative real-time PCR, and Western blotting. We found that luteolin decreased the expression of BRAF-activated long noncoding RNA (BANCR), which further led to downregulation of TSHR and downstream oncogenic signaling. Moreover, overexpression of BANCR/TSHR signaling can largely abolish the anti-tumor effects of luteolin on thyroid carcinoma in vitro and in vivo. In conclusion, luteolin may serve as a potential important anticancer agent for thyroid carcinoma by blocking the BANCR/TSHR signaling.

Downregulation of BRAF-activated non-coding RNA suppresses the proliferation, migration and invasion, and induces apoptosis of hepatocellular carcinoma cells

The long non-coding RNA BRAF-activated non-coding RNA (BANCR) has been reported to serve essential roles in the progress of a various cancer types. The purpose of the present study was to investigate the effect of lncRNA BANCR in HCC cells. The expression of BANCR in the HCC cell line Huh7 and a normal liver cell line were determined using reverse transcription-quantitative polymerase chain reaction. The expression of BANCR in Huh7 cells was downregulated by short hairpin (sh)RNA. Subsequently, the proliferation, apoptosis, migration and invasion rates were determined, along with the activity of MAPK/ERK kinase (MEK) and mitogen-activated protein kinase signaling pathways. The results revealed that BANCR was overexpressed in Huh7 cells when compared with normal liver cells. The downregulation of BANCR significantly inhibited the proliferation and colony formation ability, and induced cell cycle arrest and apoptosis of Huh7 cells. The migration and invasion of Huh7 cells were also suppressed in BANCR shRNA-transfected cells. The downregulation of BANCR significantly inhibited the activity of MEK, extracellular signal-regulated kinase and janus kinase signaling pathways. Collectively, these findings demonstrated that the lncRNA BANCR is oncogenic in Huh7 cells, and may be a promising molecular target for HCC therapy.

MicroRNA-150 targets Rho-associated protein kinase 1 to inhibit cell proliferation, migration and invasion in papillary thyroid carcinoma

Thyroid cancer is the most prevalent malignant tumor of the endocrine organs and accounts for one third of all head and neck tumors. Dysregulation of microRNAs is well‑known to contribute to the development of various cancers, including papillary thyroid carcinoma (PTC), which accounts for 80‑90% of all thyroid cancer cases. The present study aimed to investigate the expression, functional roles of microRNA‑150 (miR‑150) and its direct target gene in PTC. miR‑150 expression in PTC tissues and cell lines was analyzed by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). After transfection with miR‑150 mimics, cell proliferation, migration and invasion was analyzed by MTT and Transwell assays, respectively. Bioinformatics analysis was performed to investigate the potential target genes of miR‑150, which were then confirmed by luciferase reporter assay, RT‑qPCR and western blotting. Functional assays were also applied to investigate the effects of endogenous Rho‑associated protein kinase 1 (ROCK1) in PTC. miR‑150 was demonstrated to be significantly downregulated in PTC tissues and cell lines. In addition, reduced miR‑150 expression was obviously correlated with TNM stage and lymph node metastasis in PTC patients. Restoration of miR‑150 expression significantly inhibited PTC cell proliferation, migration and invasion in vitro. Furthermore, ROCK1 was identified as a direct target gene of miR‑150. Therefore, ROCK1 knockdown may serve tumor suppressive functions in PTC, induced by miR‑150 overexpression. In conclusion, miR‑150 overexpression in PTC may inhibit growth and metastasis of PTC cells. miR‑150/ROCK1‑based targeted therapy may be a potential strategy for the treatment of PTC.

Identification of Long Noncoding RNAs Deregulated in Papillary Thyroid Cancer and Correlated with BRAFV600E Mutation by Bioinformatics Integrative Analysis

Papillary Thyroid Cancer (PTC) is an endocrine malignancy in which BRAF^V600E oncogenic mutation induces the most aggressive phenotype. In this way, considering that lncRNAs are arising as key players in oncogenesis, it is of high interest the identification of BRAF^V600E-associated long noncoding RNAs, which can provide possible candidates for secondary mechanisms of BRAF-induced malignancy in PTC. In this study, we identified differentially expressed lncRNAs correlated with BRAF^V600E in PTC and, also, extended the cohort of paired normal and PTC samples to more accurately identify differentially expressed lncRNAs between these conditions. Indirectly validated targets of the differentially expressed lncRNAs in PTC compared to matched normal samples demonstrated an involvement in surface receptors responsible for signal transduction and cell adhesion, as well as, regulation of cell death, proliferation and apoptosis. Targets of BRAF^V600E-correlated lncRNAs are mainly involved in calcium signaling pathway, ECM-receptor interaction and MAPK pathway. In summary, our study provides candidate lncRNAs that can be either used for future studies related to diagnosis/prognosis or as targets for PTC management.

MALAT1 Long Non-coding RNA Expression in Thyroid Tissues: Analysis by In Situ Hybridization and Real-Time PCR

Long non-coding RNAs (lncRNAs) are important for transcription and for epigenetic or posttranscriptional regulation of gene expression and may contribute to carcinogenesis. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), an lncRNA involved in the regulation of the cell cycle, cell proliferation, and cell migration, is known to be deregulated in multiple cancers. Here, we analyzed the expression of MALAT1 on 195 cases of benign and malignant thyroid neoplasms by using tissue microarrays for RNA in situ hybridization (ISH) and real-time PCR. MALAT1 is highly expressed in normal thyroid (NT) tissues and thyroid tumors, with increased expression during progression from NT to papillary thyroid carcinomas (PTCs) but is downregulated in poorly differentiated thyroid cancers (PDCs) and anaplastic thyroid carcinomas (ATCs) compared to NT. Induction of epithelial to mesenchymal transition (EMT) by transforming growth factor (TGF)-beta in a PTC cell line (TPC1) led to increased MALAT1 expression, supporting a role for MALAT1 in EMT in thyroid tumors. This is the first ISH study of MALAT1 expression in thyroid tissues. It also provides the first piece of evidence suggesting MALAT1 downregulation in certain thyroid malignancies. Our findings support the notion that ATCs may be molecularly distinct from low-grade thyroid malignancies and suggest that MALAT1 may function both as an oncogene and as a tumor suppressor in different types of thyroid tumors.

Long non-coding RNAs act as regulators of cell autophagy in diseases (Review)

Identification of long non-coding RNAs (lncRNAs) has provided a substantial increase in our understanding of the non-coding transcriptome. Studies have revealed a crucial function of lncRNAs in the modulation of cell autophagy in vitro and in vivo, further contributing to the hallmarks of disease phenotypes. These findings have profoundly altered our understanding of disease pathobiology, and may lead to the emergence of new biological concepts underlying autophagy-associated diseases, such as the carcinomas. Studies on the molecular mechanism of the lncRNA-autophagy axis may offer additional avenues for therapeutic intervention and biomarker assessment. In this review, we discuss recent findings on the multiple molecular roles of regulatory lncRNAs in the signaling pathways of cell autophagy. The emerging knowledge in this rapidly advancing field will offer novel insights into human diseases, especially cancers.

Epigenetic modulators of thyroid cancer

There are some well known factors involved in the etiology of thyroid cancer, including iodine deficiency, radiation exposure at early ages, or some genetic changes. However, epigenetic modulators that may contribute to development of these tumors and be helpful to for both their diagnosis and treatment have recently been discovered. The currently known changes in DNA methylation, histone modifications, and non-coding RNAs in each type of thyroid carcinoma are reviewed here.

Comprehensive analysis of long noncoding RNA–mRNA co-expression patterns in thyroid cancer

Novel molecular-targeted treatments show great prospects for radioiodine-refractory and surgically inoperable thyroid carcinomas.

Genome-Wide Expression Screening Discloses Long Noncoding RNAs Involved in Thyroid Carcinogenesis

CONTEXT

Long noncoding RNAs (lncRNAs) regulate pathological processes, yet their potential roles in papillary thyroid carcinoma (PTC) are poorly understood.

OBJECTIVE

To profile transcriptionally dysregulated lncRNAs in PTC and identify lncRNAs associated with clinicopathological characteristics.

DESIGN

We performed RNA sequencing of 12 paired PTC tumors and matched noncancerous tissues and correlated the expression of lncRNAs with clinical parameters. The 2 most significantly dysregulated lncRNAs were studied in an Ohio PTC cohort (n = 109) and in PTC data (n = 497) from The Cancer Genome Atlas.

SETTING

A combination of laboratory-based studies and computational analysis using clinical data and samples and a publically available database.

MAIN OUTCOME MEASURES

Correlation between expression values and clinical parameters.

RESULTS

We identified 218 lncRNAs showing differential expression in PTC (fold change ≥ 2.0, P < .01). Significant correlation was observed between the expression of 2 lncRNAs (XLOC_051122 and XLOC_006074) and 1) lymph node metastasis (N stage) and 2) BRAF(V600E) mutation. Among patients with wild-type BRAF, the expression of these 2 lncRNAs showed significantly higher levels in the patients with lymph node metastasis. In silico analysis of these lncRNAs pinpointed cell movement and cellular growth and proliferation as targeted functions.

CONCLUSIONS

Comprehensive expression screening identified 2 novel lncRNAs associated with risk factors of adverse prognosis in PTC patients. These lncRNAs may be novel players in PTC carcinogenesis.

Non-Coding RNAs in Thyroid Cancer

Non-coding (nc)RNAs are divided into small ncRNAs and long ncRNAs (lncRNAs). MicroRNAs (miRNAs) are small ncRNAS which are around 22 nucleotides in length that mediate post-transcriptional gene silencing. LncRNAs are greater than 200 bp in length. Each ncRNA can have multiple targets and can be regulated by multiple genetic factors. Because ncRNAs are not translated into proteins, they can only be detected at the nucleic acid level by in situ hybridization, by RT-PCR, or by sequencing which makes their detection more challenging in the routine pathology laboratory. A great deal of new information has accumulated about miRNAs in thyroid tissues during the past decade. Some of these studies have shown that deregulation of miRNAs may be useful in diagnostic pathology. Information about the role of lncRNA in the development of thyroid tumors is in the early stages of development, but new information is accumulating rapidly. In this review, we will discuss the recent progress in our understanding of the relationship between ncRNAs and the development of thyroid cancers and the potential uses of ncRNAs in the diagnosis and prognosis of thyroid tumors.