Emerging roles of circular RNAs in thyroid cancer

Circ0005654 as a new biomarker of thyroid cancer interacting with SP1 to influence the prognosis: A case-control study

Circular RNAs (CircRNAs) have been reported to play key roles in the progression of various cancers, including thyroid cancer (TC). Transcription factor 1 (SP1) promotes the development of thyroid cancer. This study aims at investigating the expression level of Circ0005654 in combination with Transcription factor1 (SP1) in patients with TC for diagnostic and therapeutic purposes. A total of 76 patients with thyroid cancer underwent radical surgery. Intraoperatively, thyroid cancer tissues and paired adjacent tissues and the corresponding clinicopathological data were collected. The expression of SP1 and β-catenin in thyroid cancer and adjacent tissues was determined by immunohistochemistry (IHC) while the Circ0005654 expression level was measured by semiquantitative real-time polymerase chain reaction (sqRT-PCR). Then, we compared the variability of Circ0005654, SP1, and Wnt/β-catenin expression in cancerous and adjacent tissues and determined the relationship between the correlation analysis and the clinicopathological features of the thyroid cancer patients. The diagnostic value of Circ0005654 in thyroid cancer tissues was analyzed with the help of the receiver operating characteristic (ROC) curve, counting the 3-year postoperative survival rate, and analyzing the effect of Circ0005654 and SP1 protein levels on the 3-year survival rate of the patients. sqRT-PCR showed that the expression level of Circ0005654 in thyroid cancer tissue was significantly higher than that of adjacent tissues. The area under the ROC of Circ0005654 was 0.9553, 95% confidence interval: (0.9211-0.9895) with a cutoff value of 0.7895, a sensitivity of 92.11%, and a specificity of 86.84%. The IHC results showed that the expression level of SP1, β-catenin, and Wnt was higher in cancer tissues than in adjacent tissues; Circ0005654, SP1, Wnt/β-catenin expression levels were associated with tumor diameter, lymph node metastasis, TNM stage, and envelope invasion (all P < .05). According to the Circ0005654 expression level in thyroid cancer tissue, the 3-year survival rate of the high expression group was 77.5% and 94.4% in the low expression group with a statistically significant difference; the 3-year survival rate of SP1 positive and negative patients was 78.6% and 100%, respectively, with the data being significantly different. Circ0005654 may serve as a potential biomarker for thyroid cancer diagnosis and may be involved in the development of thyroid cancer.

Noncoding RNAs in Thyroid-Follicular-Cell-Derived Carcinomas

Simple Summary

Thyroid tumors represent the most common neoplastic pathology of the endocrine system. Mutations occurring in oncogenes and tumor suppressor genes are responsible for thyroid carcinogenesis; however, the complete mutational landscape characterizing these neoplasias has not been completely unveiled. It has been established that only the 2% of the human genome codes for proteins, suggesting that the vast majority of the genome has regulatory capabilities, which, if altered, could account for the onset of cancer. Hence, many scientific efforts are currently focused on the characterization of the heterogeneous class of noncoding RNAs, which represent an abundant part of the transcribed noncoding genome. In this review, we mainly focus on the involvement of microRNAs, long noncoding RNAs, and pseudogenes in thyroid cancer. The determination of the diagnosis, prognosis, and treatment of thyroid cancers based on the evaluation of the noncoding RNA network could allow the implementation of a more personalized approach to fighting these pathologies.

Abstract

Among the thyroid neoplasias originating from follicular cells, we can include well-differentiated carcinomas, papillary (PTC) and follicular (FTC) thyroid carcinomas, and the undifferentiated anaplastic (ATC) carcinomas. Several mutations in oncogenes and tumor suppressor genes have already been observed in these malignancies; however, we are still far from the comprehension of their full regulation-altered landscape. Even if only 2% of the human genome has the ability to code for proteins, most of the noncoding genome is transcribed, constituting the heterogeneous class of noncoding RNAs (ncRNAs), whose alterations are associated with the development of several human diseases, including cancer. Hence, many scientific efforts are currently focused on the elucidation of their biological role. In this review, we analyze the scientific literature regarding the involvement of microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and pseudogenes in FTC, PTC, and ATC. Recent findings emphasized the role of lncRNAs in all steps of cancer progression. In particular, lncRNAs may control progression steps by regulating the expression of genes and miRNAs involved in cell proliferation, apoptosis, epithelial–mesenchymal transition, and metastatization. In conclusion, the determination of the diagnosis, prognosis, and treatment of cancer based on the evaluation of the ncRNA network could allow the implementation of a more personalized approach to fighting thyroid tumors.

Circ_0061140 Contributes to the Malignant Progression in Ovarian Cancer Cells by Mediating the RAB1A Level Through Sponging miR-361-5p

Ovarian cancer (OC) progression is related to many functional molecules, including circular RNAs (circRNAs). Hsa_circ_0061140 (circ_0061140) promoted cell growth and metastasis in OC. The aim of this study was to explore a specific functional mechanism of circ_0061140. Reverse transcription-quantitative polymerase chain reaction was performed for expression analysis of circ_0061140, microRNA-361-5p (miR-361-5p), and Ras-like protein in rat brain 1A (RAB1A). Cell proliferation was determined using Cell Counting Kit-8 assay, EdU assay, and colony formation assay. The migration and invasion were assessed through transwell assay. Tube formation assay was used for angiogenesis analysis. Cell apoptosis was evaluated using flow cytometry. The protein levels of epithelial-to-mesenchymal transition (EMT) markers and RAB1A were detected via western blot. Target analysis was performed by dual-luciferase reporter assay and RNA immunoprecipitation assay. In vivo research was conducted using xenograft model. The circ_0061140 level was upregulated in OC samples and cells. Downregulation of circ_0061140 impeded proliferation, migration, invasion, EMT, and angiogenesis of OC cells. Circ_0061140 directly interacted with miR-361-5p to act as a miRNA sponge. The miR-361-5p inhibition reversed the si-circ_0061140-induced anti-tumor function in OC cells. RAB1A was a downstream target of miR-361-5p, and miR-361-5p served as a tumor repressor in OC via inhibiting the level of RAB1A. Circ_0061140 could increase the RAB1A expression by sponging miR-361-5p in OC cells. Circ_0061140 also facilitated tumorigenesis in vivo through targeting the miR-361-5p/RAB1A axis. All results demonstrated that circ_0061140 promoted OC development by inhibiting miR-361-5p to upregulate the expression of RAB1A.