Long noncoding RNA PVT1 enhances the viability and invasion of papillary thyroid carcinoma cells by functioning as ceRNA of microRNA-30a through mediating expression of insulin like growth factor 1 receptor

lncRNA PVT1 silencing inhibits gastric cancer cells' progression via enhancing chemosensitivity to paclitaxel

Gastric cancer (GC) is one of the leading causes of cancer-related deaths worldwide because of its high morbidity and the absence of effective therapies. Even though paclitaxel is a powerful anticancer chemotherapy drug, recent studies have indicated its ineffectiveness against GC cells. Long non-coding RNA (lncRNA) PVT1 has a high expression in GC cells and increases the progression of tumors via inducing drug resistance. In the present study, the effects of the siRNA-mediated lncRNA PVT1 gene silencing along with paclitaxel treatment on the rate of apoptosis, growth, and migration of AGS GC cells were investigated. AGS cells were cultured and then transfected with siRNA PVT1 using electroporation. The MTT test was used to examine the effect of treatments on the viability of cultured cells. Furthermore, the flow cytometry method was used to evaluate the impact of treatments on the cell cycle process and apoptosis induction in GC cells. Finally, the mRNA expression of target genes was assessed using the qRT-PCR method. The results showed that lncRNA PVT1 gene suppression, along with paclitaxel treatment, reduces the viability of cancer cells and significantly increases the apoptosis rate of cancer cells and the number of cells arrested in the G2/M phase compared to the control group. Based on the results of qRT-PCR, combined treatment significantly decreased the expression of MMP3, MMP9, MDR1, MRP1, Bcl-2, k-Ras, and c-Myc genes and increased the expression of the Bax gene compared to the control group. The results of our study showed that lncRNA PVT1 gene targeting, together with paclitaxel treatment, induces apoptosis, inhibits growth, alleviates drug resistance, and reduces the migratory capability of GC cells. Therefore, there is a need for further investigations to evaluate the feasibility and effectiveness of this approach in vivo in animal models.

Role of Long Intergenic Noncoding RNAs in Cancers with an Overview of MicroRNA Binding

Long intergenic noncoding RNAs are transcripts originating from the regions without annotated coding genes. They are located mainly in the nucleus and regulate gene expression. Long intergenic noncoding RNAs can be also found in the cytoplasm acting as molecular sponges of certain microRNAs. This is crucial in various biological and signaling pathways. Expression levels of many long intergenic noncoding RNAs are disease related. In this article, we focus on the long intergenic noncoding RNAs and their relation to different types of cancer. Studies showed that abnormal expression of long intergenic noncoding RNA deregulates signaling pathways due to the disrupted free microRNA pool. Hampered signaling pathways leads to abnormal cell proliferation and restricts cell death, thus resulting in oncogenesis. This review highlights promising therapeutic targets and enables the identification of potential biomarkers specific for a certain type of cancer. Moreover, we provide an outline of long intergenic noncoding RNAs/microRNA axes, which might be applied in further detailed experiments broadening our knowledge about the cellular role of those RNA species.

In silico analysis to identify novel ceRNA regulatory axes associated with gallbladder cancer

Competitive endogenous RNA (ceRNA) networks are reported to play a crucial role in regulating cancer-associated genes. Identification of novel ceRNA networks in gallbladder cancer (GBC) may improve the understanding of its pathogenesis and might yield useful leads on potential therapeutic targets for GBC. For this, a literature survey was done to identify differentially expressed lncRNAs (DELs), miRNAs (DEMs), mRNAs (DEGs) and proteins (DEPs) in GBC. Ingenuity pathway analysis (IPA) using DEMs, DEGs and DEPs in GBC identified 242 experimentally observed miRNA-mRNA interactions with 183 miRNA targets, of these 9 (CDX2, MTDH, TAGLN, TOP2A, TSPAN8, EZH2, TAGLN2, LMNB1, and PTMA) were reported at both mRNA and protein levels. Pathway analysis of 183 targets revealed p53 signaling among the top pathway. Protein-protein interaction (PPI) analysis of 183 targets using the STRING database and cytoHubba plug-in of Cytoscape software revealed 5 hub molecules, of which 3 of them (TP53, CCND1 and CTNNB1) were associated with the p53 signaling pathway. Further, using Diana tools and Cytoscape software, novel lncRNA-miRNA-mRNA networks regulating the expression of TP53, CCND1, CTNNB1, CDX2, MTDH, TOP2A, TSPAN8, EZH2, TAGLN2, LMNB1, and PTMA were constructed. These regulatory networks may be experimentally validated in GBC and explored for therapeutic applications.

lncRNA PVT1: a novel oncogene in multiple cancers

Long noncoding RNAs are involved in epigenetic gene modification, including binding to the chromatin rearrangement complex in pre-transcriptional regulation and to gene promoters in gene expression regulation, as well as acting as microRNA sponges to control messenger RNA levels in post-transcriptional regulation. An increasing number of studies have found that long noncoding RNA plasmacytoma variant translocation 1 (PVT1) plays an important role in cancer development. In this review of a large number of studies on PVT1, we found that PVT1 is closely related to tumor onset, proliferation, invasion, epithelial–mesenchymal transformation, and apoptosis, as well as poor prognosis and radiotherapy and chemotherapy resistance in some cancers. This review comprehensively describes PVT1 expression in various cancers and presents novel approaches to the diagnosis and treatment of cancer.

The efficacy and safety of microwave ablation versus conventional open surgery for the treatment of papillary thyroid microcarcinoma: a systematic review and meta-analysis

Background

Microwave ablation (MWA) technology has been applied to the treatment of papillary thyroid microcarcinoma (PTMC); however, its use as an alternative to conventional open surgery (OS) remains controversial, because it belongs to non-tumor radical treatment. Our article sought to compare the efficacy and safety of MWA and OS in the treatment of PTMC.

Methods

We searched seven databases for studies evaluating the treatment of patients with PTMC using MWA as intervention group and OS as control group, the main outcome contained intra-operative, post-operative and follow-up outcomes. Review Manager 5.4 was used to estimate the effects of the results of the included articles and Cochrane Risk of Bias 2.0 was used to assess the risk of bias. The data were pooled to calculate the mean differences (MD) with 95% confidence intervals (CIs) for the continuous data and the odds ratio (OR) with 95% CIs for the dichotomous data.

Results

A total of 13 studies, comprising 1,088 and 1,081 patients in the MWA and OS groups, respectively, were identified that compared the results of MWA to OS in the treatment of PTMC. All of the articles were at low risk of bias. There were no differences in terms of the recurrence rate (OR =0.80, 95% CI: 0.37 to 1.77; P=0.59) or lymph node metastasis (OR =0.71, 95% CI: 0.26 to 1.95; P=0.51) between the 2 groups. However, compared to the OS group, the MWA group had a shorter operation time (MD =-44.85, 95% CI: 5.73 to 20.68; P<0.00001), less intra-operative blood loss (MD =-23.37, 95% CI: -29.57 to -17.17; P<0.00001), a smaller surgical incision (MD =-47.04, 95% CI: -81.93 to -12.14; P=0.008), a shorter postoperative hospital stay (MD =-4.19, 95% CI: -5.46 to -2.92; P<0.00001), lower hospitalization expenses (MD =-85.65, 95% CI: -133.86 to -37.45; P<0.00001), and fewer complications (OR =0.23, 95% CI: 0.16 to 0.33; P<0.00001).

Conclusions

This meta-analysis suggests that MWA is better than OS at treating PTMC in terms of both intra-operative and post-operative outcomes. Due to the quality and number of the included studies, the long-term effects and suitability of MWA in the treatment of PTMC need to be further studied.

Biological networks in gestational diabetes mellitus: insights into the mechanism of crosstalk between long non-coding RNA and N6-methyladenine modification

Background

Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy. The mechanism underlying the crosstalk between long non-coding RNAs (lncRNAs) and N⁶-methyladenine (m6A) modification in GDM remain unclear.

Methods

We generated a lncRNA-mediated competitive endogenous RNA (ceRNA) network using comprehensive data from the Gene Expression Omnibus database, published data, and our preliminary findings. m6A-related lncRNAs were identified based on Pearson correlation coefficient (PCC) analysis using our previous profiles. An integrated pipeline was established to constructed a m6A-related subnetwork thereby predicting the potential effects of the m6A-related lncRNAs.

Results

The ceRNA network was composed of 16 lncRNAs, 17 microRNAs, 184 mRNAs, and 338 edges. Analysis with the Kyoto Encyclopedia of Genes and Genomes database demonstrated that genes in the ceRNA network were primarily involved in the development and adverse outcomes of GDM, such as those in the fatty acid-metabolism pathway, the peroxisome proliferator-activated receptor signaling pathway, and thyroid hormone signaling pathway. Four m6A-related lncRNAs were involved in the ceRNA network, including LINC00667, LINC01087, AP000350.6, and CARMN. The m6A-related subnetwork was generated based on these four lncRNAs, their ceRNAs, and their related m6A regulators. Genes in the subnetwork were enriched in certain GDM-associated hormone (thyroid hormone and oxytocin) signaling pathways. LINC00667 was positively correlated with an m6A “reader” (YTHDF3; PCC = 0.95) and exhibited the highest node degree in the ceRNA network. RIP assays showed that YTHDF3 directly bind LINC00667. We further found that MYC possessed the highest node degree in a protein–protein interaction network and competed with LINC00667 for miR-33a-5p. qPCR analysis indicated that LINC00667, YTHDF3 and MYC levels were upregulated in the GDM placentas, while miR-33a-5p was downregulated. In a support-vector machine classifier, an m6A-related module composed of LINC00667, YTHDF3, MYC, and miR-33a-5p showed excellent classifying power for GDM in both the training and the testing dataset, with an accuracy of 76.19 and 71.43%, respectively.

Conclusions

Our results shed insights into the potential role of m6A-related lncRNAs in GDM and have implications in terms of novel therapeutic targets for GDM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04716-w.

Analysis of anti-apoptotic PVT1 oncogene and apoptosis-related proteins (p53, Bcl2, PD-1, and PD-L1) expression in thyroid carcinoma

BACKGROUND

An aberrant expression of long non-coding RNA PVT1 has been associated with apoptosis in various cancer types. We aimed to explore the PVT1 and four apoptosis-related proteins (p53, Bcl2, and PD-1/PD-L1) signature in thyroid cancer (TC).

METHODS

The PVT1 expression level was measured in 64 FFPE TC paired samples by real-time quantitative PCR. Overall and stratified analyses by different clinicopathological features were done. The apoptotic proteins were evaluated by immunohistochemistry staining.

RESULTS

Overall analysis showed significant PVT1upregulation in TC tissues (p < 0.001). Similarly, subgroup analysis by BRAFV600E mutation showed consistent results. Lower expression of p53 was associated with mortality (p = 0.001). Bcl2 overexpression was associated with greater tumor size (p = 0.005). At the same time, HCV-positive cases were associated with repressed Bcl2 expression levels (54.3% in HCV-negative vs. 6.9% in HCV-positive cases, p = 0.011). PD-1 expression was associated with lymph node metastasis (p = 0.004). Enhanced PD-L1 expression in the tumor was associated with a higher tumor stage, lymphovascular invasion, and mortality risk. Kaplan-Meier curves for overall survival showed that low p53 and high PD-L1 expressions were associated with lower survival time. The p53-positive staining is associated with a 90% decreased mortality risk (HR = 0.10, 95%CI = 0.02-0.47, p = 0.001), while patients with high PD-L1 were five times more likely to die (HR = 4.74, 95%CI = 1.2-18.7, p = 0.027).

CONCLUSION

Our results confirm the upregulation of PVT1 in TC. The apoptosis-related proteins (p53, Bcl2, and PD-1/PD-L1) showed different prognostic utility in TC patients; in particular, low p53 and high PD-L1 expressions associated with low survival times. Further large-scale and mechanistic studies are warranted.

MicroRNAs in Papillary Thyroid Cancer: What Is New in Diagnosis and Treatment

Introduction

Papillary thyroid cancer (PTC) accounts for up to 80% of thyroid malignancies. New diagnostic and therapeutic options are suggested including innovative molecular methods. MicroRNAs (miRNAs) are nonprotein coding single-stranded RNAs that regulate many cell processes. The aim of the present study is to review the deregulated miRNAs associated with PTCs.

Methods

A bibliographic research was conducted, resulting in 272 articles referred to miRNAs and PTC. Regarding our exclusion criteria, 183 articles were finally included in our review.

Results

A remarkably large number of miRNAs have been found to be deregulated during PTC manifestation in the literature. The deregulated miRNAs are detected in tissue samples, serum/plasma, and FNA samples of patients with PTC. These miRNAs are related to several molecular pathways, involving genes and proteins responsible for important biological processes. MiRNA deregulation is associated with tumor aggressiveness, including larger tumor size, multifocality, extrathyroidal extension, lymphovascular invasion, lymph node and distant metastasis, and advanced tumor node metastasis stage.

Conclusion

MiRNAs are proposed as new diagnostic and therapeutic tools regarding PTC. They could be essential biomarkers for PTC diagnosis applied in serum and FNA samples, while their contribution to prognosis is of great importance.

Epigenetic modification and BRAF gene mutation in thyroid carcinoma

Thyroid cancer remains the most prevailing endocrine malignancy, and a progressively increasing incidence rate has been observed in recent years, with 95% of thyroid cancer represented by differentiated thyroid carcinomas. The genetics and epigenetics of thyroid cancer are gradually increasing, and gene mutations and methylation changes play an important roles in its occurrence and development. Although the role of RAS and BRAF mutations in thyroid cancer have been partially clarified,but the pathogenesis and molecular mechanisms of thyroid cancer remain to be elucidated. Epigenetic modification refer to genetic modification that does not change the DNA sequence of a gene but causes heritable phenotypic changes in its expression. Epigenetic modification mainly includes four aspects: DNA methylation, chromatin remodelling, noncoding RNA regulation, and histone modification. This article reviews the importance of thyroid cancer epigenetic modification and BRAF gene mutation in the treatment of thyroid cancer.

A ceRNA network mediated by LINC00475 in papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the most frequent histological type of differentiated thyroid carcinoma. Long noncoding RNAs (lncRNAs) have been widely reported to play a key role in human malignancies, and PTC is included. This study aimed to find out the functions and mechanism of lncRNA LINC00475 in PTC. LINC00475 was upregulated in PTC cells and was mainly located in the cytoplasm according to reverse-transcription polymerase chain reaction analyses and subcellular fractionation assays. As shown by cell counting kit-8 assays, ethynyl deoxyuridine incorporation assays, wound healing assays, and transwell assays, LINC00475 knockdown suppressed cell viability, proliferation, migration, and invasion. Mechanistically, LINC00475 upregulated the expression of messenger RNA zinc finger CCHC-type containing 12 (ZCCHC12) by binding to miR-376c-3p. ZCCHC12 was a direct target gene of miR-376c-3p in PTC cells. The relationship between miR-376c-3p and LINC00475 (or ZCCHC12) in PTC cells was probed by luciferase reporter assays, RNA pulldown assays, and RNA immunoprecipitation assays. In addition, both mRNA and protein levels of ZCCHC12 were downregulated due to miR-376c-3p overexpression or LINC00475 silencing. ZCCHC12 overexpression partially reversed the suppressive effect of LINC00475 knockdown on malignant behaviors of PTC cells. In conclusion, LINC00475 promotes PTC cell proliferation, migration, and invasion by upregulating ZCCHC12 via the interaction with miR-376c-3p.

circRPS28 (hsa_circ_0049055) is a novel contributor for papillary thyroid carcinoma by regulating cell growth and motility via functioning as ceRNA for miR-345-5p to regulate frizzled family receptor 8 (FZD8)

Circular RNA 40S ribosomal protein S28 (circRPS28; hsa_circ_0049055) is upregulated in papillary thyroid carcinoma (PTC) patients. However, its role remained uncovered in the progression of PTC. Above all, expression of circRPS28 was determined in PTC samples by real-time quantitative PCR and circRPS28 was highly expressed in tumor tissues and cells. Besides, circRPS28 was predominantly distributed in the cytoplasm. Functional experiments were launched using colony formation assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, 5-ethynyl-2-deoxyuridine (EdU) assay, transwell assays, scratch wound assay, and flow cytometry. As a result, blocking circRPS28 restrained PTC cell viability, EdU positive cell rate, colony formation number, wounding healing rate, and numbers of migration and invasion cells, accompanied with apoptosis rate promotion. These effects paralleled with low B-cell lymphoma (Bcl)-2 level and high Bcl-2-associated X protein (Bax), matrix metalloproteinase-2 (MMP2), and MMP9 levels, as analyzed by western blotting. Overexpressing microRNA (miR)-345-5p exerted similar roles to circRPS28 silencing. Notably, dual-luciferase reporter assay and RNA immunoprecipitation confirmed the target relationship between circRPS28 and miR-345-5p, miR-345-5p and frizzled family receptor 8 (FZD8). Downregulating miR-345-5p abrogated effects of circRPS28 blockage in PTC cells, and restoring FZD8 counteracted miR-345-5p roles, either. Furthermore, xenograft tumor model was established in mice, and exhausting circRPS28 delayed the growth of PTC cells in vivo by regulating miR-345-5p and FZD8. In conclusion, we demonstrated that blocking circRPS28 and/or promoting miR-345-5p suppressed PTC cell growth and motility via regulating FZD8. This study might suggest a novel circRPS28/miR-345-5p/FZD8 competing endogenous RNA pathway in PTC.

MiR-873-5p: A Potential Molecular Marker for Cancer Diagnosis and Prognosis

miR-873 is a microRNA located on chromosome 9p21.1. miR-873-5p and miR-873-3p are the two main members of the miR-873 family. Most studies focus on miR-873-5p, and there are a few studies on miR-873-3p. The expression level of miR-873-5p was down-regulated in 14 cancers and up-regulated in 4 cancers. miR-873-5p has many targeted genes, which have unique molecular functions such as catalytic activity, transcription regulation, and binding. miR-873-5p affects cancer development through the PIK3/AKT/mTOR, Wnt/β-Catenin, NF-κβ, and MEK/ERK signaling pathways. In addition, the target genes of miR-873-5p are closely related to the proliferation, apoptosis, migration, invasion, cell cycle, cell stemness, and glycolysis of cancer cells. The target genes of miR-873-5p are also related to the efficacy of several anti-cancer drugs. Currently, in cancer, the expression of miR-873-5p is regulated by a variety of epigenetic factors. This review summarizes the role and mechanism of miR-873-5p in human tumors shows the potential value of miR-873-5p as a molecular marker for cancer diagnosis and prognosis.

LINC00514 upregulates CCDC71L to promote cell proliferation, migration and invasion in triple-negative breast cancer by sponging miR-6504-5p and miR-3139

BACKGROUND

Long noncoding RNAs (lncRNAs) have recently identified as essential gene modulators in numerous cancers. Previous studies have confirmed the oncogenic role of long intergenic nonprotein-coding RNA 00514 (LINC00514) in some cancers. Nevertheless, its biological function and mechanism remain unclear in triple-negative breast cancer (TNBC).

METHODS

Herein, we detected LINC00514 expression level in TNBC tissues and cells using RT-qPCR. The function of LINC00514 in TNBC cellular activities was assessed by colony formation, EdU, wound healing, transwell assays and flow cytometry analysis.

RESULTS

The binding between miR-6504-5p/miR-3139 and LINC00514/CCDC71L was validated by luciferase reporter assay. The results indicated that LINC00514 expression was upregulated in TNBC tissues and cells. Furthermore, it was manifested that silenced LINC00514 restrained cell proliferative, migratory and invasive abilities and promoted cell apoptosis. In mechanism, LINC00514 was revealed to sequester miR-6504-5p and miR-3139 in TNBC cells. Furthermore, the low level of miR-6504-5p and miR-3139 was identified in TNBC tissues and cells. Overexpression of miR-6504-5p or miR-3139 inhibited cell growth and migration in TNBC. CCDC71L was recognized as a common downstream gene of miR-6504-5p and miR-3139. Rescue assay verified that overexpressed CCDC71L countervailed the anti-tumor influence of LINC00514 knockdown on TNBC cell proliferation, migration, invasion and apoptosis.

CONCLUSIONS

LINC00514 promote cell proliferation, migration and invasion in triple-negative breast cancer by targeting the miR-6504-5p/miR-3139/CCDC71L axis in TNBC.

Long Non-coding RNA LINC01969 Promotes Ovarian Cancer by Regulating the miR-144-5p/LARP1 Axis as a Competing Endogenous RNA

Accumulating evidence has shown that long non-coding RNAs (lncRNAs) can be used as biological markers and treatment targets in cancer and play various roles in cancer-related biological processes. However, the lncRNA expression profiles and their roles and action mechanisms in ovarian cancer (OC) are largely unknown. Here, we assessed the lncRNA expression profiles in OC tissues from The Cancer Genome Atlas (TCGA) database, and one upregulated lncRNA, LINC01969, was selected for further study. LINC01969 expression levels in 41 patients were verified using quantitative real-time polymerase chain reaction (qRT-PCR). The in vitro effects of LINC01969 on OC cell migration, invasion, and proliferation were determined by the CCK-8, ethynyl-2-deoxyuridine (EdU), wound healing, and Transwell assays. Epithelial–mesenchymal transition (EMT) was evaluated using qRT-PCR and Western blotting. The molecular mechanisms of LINC01969 in OC were assessed through bioinformatics analysis, RNA-binding protein immunoprecipitation (RIP), dual luciferase reporter gene assays, and a rescue experiment. Finally, in vivo experiments were conducted to evaluate the functions of LINC01969. The results of the current study showed that LINC01969 was dramatically upregulated in OC, and patients with lower LINC01969 expression levels tended to have better overall survival. Further experiments demonstrated that LINC01969 promoted the migration, invasion, and proliferation of OC cells in vitro and sped up tumor growth in vivo. Additionally, LINC01969, which primarily exists in the cytoplasm, boosted LARP1 expression by sponging miR-144-5p and promoted the malignant phenotypes of OC cells. In conclusion, the LINC01969/miR-144-5p/LARP1 axis is a newly identified regulatory signaling pathway involved in OC progression.

8q24.21 Locus: A Paradigm to Link Non-Coding RNAs, Genome Polymorphisms and Cancer

The majority of the human genome is comprised of non-protein-coding genes, but the relevance of non-coding RNAs in complex diseases has yet to be fully elucidated. One class of non-coding RNAs is long non-coding RNAs or lncRNAs, many of which have been identified to play a range of roles in transcription and translation. While the clinical importance of the majority of lncRNAs have yet to be identified, it is puzzling that a large number of disease-associated genetic variations are seen in lncRNA genes. The 8q24.21 locus is rich in lncRNAs and very few protein-coding genes are located in this region. Interestingly, the 8q24.21 region is also a hot spot for genetic variants associated with an increased risk of cancer. Research focusing on the lncRNAs in this area of the genome has indicated clinical relevance of lncRNAs in different cancers. In this review, we summarise the lncRNAs in the 8q24.21 region with respect to their role in cancer and discuss the potential impact of cancer-associated genetic polymorphisms on the function of lncRNAs in initiation and progression of cancer.

LncRNA PVT1 Acts as a Tumor Promoter in Thyroid Cancer and Promotes Tumor Progression by Mediating miR-423-5p-PAK3

Introduction

Thyroid cancer (TC) is an endocrine tumor whose risk of onset has been rising, so the deep understanding of its molecular mechanism helps formulate new treatment strategies.

Methods

This paper was aimed at exploring the regulatory mechanism of long non-coding RNA (LncRNA) plasmacytoma variant translocation 1 (PVT1) in TC. The expression of PVT1, miR-423-5p and p21-activated kinase 3 (PAK3) in TC tissues and cell lines was detected by real-time PCR. PAK3 levels were detected by Western blot. Regulatory relationships between target genes and the proliferation, invasion and apoptosis of cells and genes were analyzed.

Results

PVT1 and PAK3 upregulated while miR-423-5p downregulated in the tissues and cell lines. PVT1 downregulation inhibited TC cells from malignantly proliferating and invading, and promoted their apoptosis. PVT1 specifically regulated miR-423-5p, and its overexpression could weaken the anti-tumor effect of this miR on TC cells. In addition, miR-423-5p directly targeted PAK3, and knocking down its expression could weaken the inhibitory effect of PAK3 downregulation on TC progression. Besides, PVT1 acted as a competitive endogenous RNA to sponge this miR and thus regulate PAK3 expression.

Discussion

In conclusion, PVT1 can mediate the molecular mechanism of the miR-423-5p-PAK3 axis regulatory network on regulating TC, so it is a new direction of treating the disease.

Non-Coding RNAs as Mediators of Epigenetic Changes in Malignancies

Non-coding RNAs (ncRNAs) are untranslated RNA molecules that regulate gene expressions. NcRNAs include small nuclear RNAs (snRNAs), small nucleolar RNAs (snoRNAs), ribosomal RNAs (rRNAs), transfer RNAs (tRNAs), circular RNAs (cRNAs) and piwi-interacting RNAs (piRNAs). This review focuses on two types of ncRNAs: microRNAs (miRNAs) or short interfering RNAs (siRNAs) and long non-coding RNAs (lncRNAs). We highlight the mechanisms by which miRNAs and lncRNAs impact the epigenome in the context of cancer. Both miRNAs and lncRNAs have the ability to interact with numerous epigenetic modifiers and transcription factors to influence gene expression. The aberrant expression of these ncRNAs is associated with the development and progression of tumors. The primary reason for their deregulated expression can be attributed to epigenetic alterations. Epigenetic alterations can cause the misregulation of ncRNAs. The experimental evidence indicated that most abnormally expressed ncRNAs impact cellular proliferation and apoptotic pathways, and such changes are cancer-dependent. In vitro and in vivo experiments show that, depending on the cancer type, either the upregulation or downregulation of ncRNAs can prevent the proliferation and progression of cancer. Therefore, a better understanding on how ncRNAs impact tumorigenesis could serve to develop new therapeutic treatments. Here, we review the involvement of ncRNAs in cancer epigenetics and highlight their use in clinical therapy.

ZEB1-activated LINC01123 accelerates the malignancy in lung adenocarcinoma through NOTCH signaling pathway

Growing incidence of lung adenocarcinoma (LUAD) has been detected recently. Multiple long non-coding RNAs (lncRNAs) have been proven as tumor facilitators or inhibitors by extensive works. Present study concentrated on characterizing the potential role of LINC01123 in LUAD. We explored the differential expression of LINC01123 through qRT-PCR and found the amplification of LINC01123 in LUAD cell lines. It was ascertained that LINC01123 was definitely responsible for the malignant processes of LUAD cells. Further, we validated the ceRNA network of LINC01123/miR-449b-5p/NOTCH1 in LUAD via mechanical experiments. As a transcriptional factor related to epithelial mesenchymal transition (EMT), ZEB1 was responsible for the transcriptional activation of both LINC01123 and NOTCH1. The involvement of NOTCH signaling in LUAD was interrogated through evaluating functional changes after treating with FLI-06 (NOTCH pathway suppressor). It showed that FLI-06-caused NOTCH signaling inactivation suppressed malignant functions in LUAD cells. Additionally, LINC01123 facilitated NOTCH1-dependent NOTCH signaling activation. Rescue experiments probed the modulatory function of LINC01123/miR-449b-5p/NOTCH1 in LUAD cellular processes. Altogether, ZEB1-activated LINC01123 accelerates the malignancy in LUAD through miR-449b-5p/NOTCH1 axis-mediated NOTCH signaling pathway, while NOTCH1 boosts ZEB1 in return. These observations suggest the huge potential of LINC01123 as a new target for LUAD therapy.

MicroRNA in Papillary Thyroid Carcinoma: A Systematic Review from 2018 to June 2020

Simple Summary

The most common form of endocrine cancer - papillary thyroid carcinoma, has an increasing incidence. Although this disease usually has an indolent behavior, there are cases when it can evolve more aggressively. It has been known for some time that it is possible to use microRNAs for the diagnosis, prognosis and even treatment monitoring of papillary thyroid cancer. The purpose of this study is to summarize the latest information provided by publications regarding the involvement of microRNAs in papillary thyroid cancer, underling the new clinical perspectives offered by these publications.

Abstract

The involvement of micro-ribonucleic acid (microRNAs) in metabolic pathways such as regulation, signal transduction, cell maintenance, and differentiation make them possible biomarkers and therapeutic targets. The purpose of this review is to summarize the information published in the last two and a half years about the involvement of microRNAs in papillary thyroid carcinoma (PTC). Another goal is to understand the perspective offered by the new findings. Main microRNA features such as origin, regulation, targeted genes, and metabolic pathways will be presented in this paper. We interrogated the PubMed database using several keywords: “microRNA” + “thyroid” + “papillary” + “carcinoma”. After applying search filters and inclusion criteria, a selection of 137 articles published between January 2018–June 2020 was made. Data regarding microRNA, metabolic pathways, gene/protein, and study utility were selected and included in the table and later discussed regarding the matter at hand. We found that most microRNAs regularly expressed in the normal thyroid gland are downregulated in PTC, indicating an important tumor-suppressor action by those microRNAs. Moreover, we showed that one gene can be targeted by several microRNAs and have nominally described these interactions. We have revealed which microRNAs can target several genes at once.

DSCAM-AS1 accelerates cell proliferation and migration in osteosarcoma through miR-186-5p/GPRC5A signaling

Osteosarcoma (OS) is one of the most primary bone malignancies, often occurring in adolescents or children. Numerous scientific findings have introduced that long noncoding RNAs (lncRNAs) can be involved in tumor occurrence and development. Although DSCAM-AS1 has been studied in several cancers, its role and mechanism in OS are poorly understood. In this work, high level of DSCAM-AS1 was validated in OS cell lines. Depleting DSCAM-AS1 inhibited cell proliferation, migration and EMT process in OS. Subsequently, we disclosed that DSCAM-AS1 was mainly observed in the cytoplasm of OS cells and could bind with miR-186-5p in OS. Moreover, inhibiting miR-186-5p rescued the impact of silenced DSCAM-AS1 on OS progression. Additionally, GPRC5A was verified as the target downstream of miR-186-5p, and it was negatively modulated by miR-186-5p but positively regulated by DSCAM-AS1. More importantly, DSCAM-AS1 enhanced GPRC5A level in OS by sequestering miR-186-5p. Finally, up-regulating GPRC5A reversed the influences of DSCAM-AS1 repression on the oncogenic behaviors of OS cells. Knockdown of DSCAM-AS1 suppressed NPC tumor growth in vivo. All findings uncovered that DSCAM-AS1 aggravated OS progression through sponging miR-186-5p to up-regulate GPRC5A expression. Thus, we proposed DSCAM-AS1 as a probable target for OS treatment.

The Changing Face of in vitro Culture Models for Thyroid Cancer Research: A Systematic Literature Review

Background: Thyroid cancer is the most common endocrine malignancy worldwide. Primary treatment with surgery and radioactive iodine is usually successful, however, there remains a small proportion of thyroid cancers that are resistant to these treatments, and often represent aggressive forms of the disease. Since the 1950s, in vitro thyroid culture systems have been used in thyroid cancer research. In vitro culture models have evolved from 2-dimensional thyrocyte monolayers into physiologically functional 3-dimensional organoids. Recently, research groups have utilized in vitro thyroid cancer models to identify numerous genetic and epigenetic factors that are involved with tumorigenesis as well as test the efficacy of cytotoxic drugs on thyroid cancer cells and identify cancer stem cells within thyroid tumors.

Objective of Review: The objective of this literature review is to summarize how thyroid in vitro culture models have evolved and highlight how in vitro models have been fundamental to thyroid cancer research.

Type of Review: Systematic literature review.

Search Strategy: The National Institute for Health and Care Excellence (NICE) Healthcare and Databases Advanced Search (HDAS) tool was used to search EMBASE, Medline and PubMed databases. The following terms were included in the search: “in vitro” AND “thyroid cancer”. The search period was confined from January 2008 until June 2019. A manual search of the references of review articles and other key articles was also performed using Google Scholar.

Evaluation Method: All experimental studies and review articles that explicitly mentioned the use of in vitro models for thyroid cancer research in the title and/or abstract were considered. Full-text versions of all selected articles were evaluated. Experimental studies were reviewed and grouped according to topic: genetics/epigenetics, drug testing/cancer treatment, and side populations (SP)/tumor microenvironment (TME).

Results: Three thousand three hundred and seventy three articles were identified through database and manual searches. One thousand two hundred and sixteen articles remained after duplicates were removed. Five hundred and eighty nine articles were excluded based on title and/or abstract. Of the remaining 627 full-text articles: 24 were review articles, 332 related to genetic/epigenetics, 240 related to drug testing/treatments, and 31 related to SP/TME.

Conclusion:In vitro cell culture models have been fundamental in thyroid cancer research. There have been many advances in culture techniques- developing complex cellular architecture that more closely resemble tumors in vivo. Genetic and epigenetic factors that have been identified using in vitro culture models can be used as targets for novel drug therapies. In the future, in vitro systems will facilitate personalized medicine, offering bespoke treatments to patients.

DGCR5 Promotes Gallbladder Cancer by Sponging MiR-3619-5p via MEK/ERK1/2 and JNK/p38 MAPK Pathways

Gallbladder cancer (GBC) is a highly aggressive malignant cancer with poor prognosis. Long noncoding RNA (lncRNA) DiGeorge syndrome critical region gene (DGCR5) has been reported to participate in various types of cancers, but its role in GBC remains largely unknown. This study aimed to explore the functions and mechanisms of DGCR5 in GBC. Here, we found that DGCR5 was upregulated in GBC tissues and cell lines. Through functional experiments, it was demonstrated that silence of DGCR5 significantly suppressed the cell proliferation, migration, invasion, and induced apoptosis and cell cycle arrest in GBC cells. In addition, miR-3619-5p was predicted and further verified as the target of DGCR5. Moreover, miR-3619-5p was observed downregulated in GBC tissues and cell lines, and miR-3619-5p mimics repressed the GBC cell proliferation, migration, invasion and could be rescued by DGCR5 overexpression. Mechanistically, it was found that DGCR5 knockdown and miR-3619-5p mimics inactivated the MEK/ERK1/2 and JNK/p38 MAPK pathways. In addition, rescue experiments indicated that inhibition of MEK/ERK1/2 and JNK/p38 MAPK pathways could reverse the effects of DGCR5 overexpression on cell proliferation, migration and invasion. Finally, xenograft model assay was used to validate that knockdown of DGCR5 suppressed GBC via regulating MEK/ERK1/2 and JNK/p38 MAPK pathways in vivo. Taken together, it was uncovered in our study that DGCR5 exerts an oncogenic role by sponging miR-3619-5p and activating MEK/ERK1/2 and JNK/p38 MAPK pathways in GBC progression.

The Role of Long Non-Coding RNAs in Thyroid Cancer

Thyroid cancer, the most common endocrine malignancy, has become the most commonly diagnosed malignant solid tumor. Moreover, some cases have poor prognosis, and the survival period is only 3-5 months. Long noncoding RNAs (lncRNAs) are a group of functional RNA molecules more than 200 nucleotides in length that lack the ability to encode protein but participate in all aspects of gene regulation. Functionally, many lncRNAs play essential roles in epigenetic regulation at transcriptional and post-transcriptional levels via various molecular mechanisms. Recent studies have discovered important roles for lncRNAs during the complex process of carcinogenesis in thyroid cancer. In this review, we focus on lncRNAs dysregulated in thyroid cancer and summarize recently reported associations between lncRNAs and thyroid cancer in order to demonstrate the significant value of lncRNAs in diagnosis and treatment.

Six long noncoding RNAs as potentially biomarkers involved in competitive endogenous RNA of hepatocellular carcinoma

To investigate lncRNAs acting as competing endogenous RNAs (ceRNAs) involved in oncogenesis and progression of HCC. Different expressed lncRNAs, microRNAs, and mRNAs (DElncRNAs, DEmiRNAs, DEmRNAs), downloaded from The Cancer Genome Atlas (TCGA) database, were identified by edgeR package. CeRNA network was constructed based on miRcode, TargetScan, and miRTarBase. Target DEmRNAs were annotated by KEGG pathway and GO analysis. Negatively correlated lncRNA-miRNA pairs were analyzed by Pearson correlation coefficient, simultaneously, overall survival (OS) were evaluated. The expression of these lncRNAs were examined in HCC cell lines and tissues through qRT-PCR. 1070 DElncRNAs, 147 DEmiRNAs and 1993 DEmRNAs were acquired. CeRNA network was successfully established, including 27 lncRNAs, 5 miRNAs, and 30 mRNAs significantly correlated with OS. The DEmRNAs were significantly enriched in "Cell Cycle" and "pathways in cancer". Six lncRNAs and 2 miRNAs were negatively correlated. These lncRNAs were validated by qRT-PCR. These observations will provide a novel perspective to elucidate HCC pathogenesis.

Long non-coding RNA NEAT1/miR-338-3p axis impedes the progression of acute myeloid leukemia via regulating CREBRF

Background

Acute myeloid leukemia (AML) is a heterogeneous hematological disease. Our purpose of the research was to investigate the regulatory influence of long non-coding RNA (lncRNA) nuclear enriched abundant transcript 1 (NEAT1)/microRNA-338-3p (miR-338-3p)/CREB3 regulatory factor (CREBRF) in AML progression.

Methods

The associated RNA and protein levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot, respectively. Cell growth was assessed through colony formation assay and 3-(4,5-dimethylthiazol-2-y1)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Flow cytometry was exploited to determine the apoptosis rate. Cell migration and invasion were detected by transwell assay. The combination of miR-338-3p and NEAT1 or CREBRF was analyzed via the dual-luciferase reporter assay.

Results

NEAT1 and CREBRF were down-regulated in AML tissues and cells. NEAT1 up-regulation suppressed cell growth, migration and invasion but enhanced apoptosis of AML cells. Inhibition of CREBRF reverted the NEAT1-induced effects on AML cells. Moreover, NEAT1 directly targeted miR-338-3p and miR-338-3p targeted CREBRF. NEAT1/miR-338-3p could affect cellular behaviors of AML cells via the modulation of CREBRF.

Conclusion

NEAT1/miR-338-3p axis repressed the AML progression through regulating CREBRF, which might afford a favorable perspective for the AML treatment molecularly.

YY1-induced lncRNA ZFPM2-AS1 facilitates cell proliferation and invasion in small cell lung cancer via upregulating of TRAF4

Background

Newly identified lncRNA zinc finger protein, FOG family member 2 antisense RNA 1 (ZFPM2-AS1) is identified as an oncogenic gene. However, the role of ZFPM2-AS1 in small cell lung cancer (SCLC) is poorly comprehended.

Methods

The expression of genes in SCLC tissues and cells was measured by qRT-PCR. Colony formation, EdU, CCK-8, transwell and wound healing as well as in vivo assays revealed the function of ZFPM2-AS1 in SCLC. ChIP, luciferase reporter, RIP and RNA pull down assays demonstrated the binding relation among genes.

Results

ZFPM2-AS1 was significantly upregulated in SCLC tissues and cells. ZFPM2-AS1 deficiency attenuated SCLC cell proliferation, invasion and migration. In addition, ZFPM2-AS1 was transcriptionally activated by Yin Yang 1 (YY1) factor. Further, miR-3612 was confirmed as downstream miRNA of ZFPM2-AS1. Moreover, TNF receptor associated factor 4 (TRAF4) was the target gene of miR-3612 in SCLC. ZFPM2-AS1, miR-3612 and TRAF4 jointly constituted a competing endogenous RNA (ceRNA) network in SCLC. Finally, TRAF4 could countervail ZFPM2-AS1 downregulation-mediated function on SCLC cell proliferation and invasion in vitro and tumor growth in vivo.

Conclusion

Our study elucidated the oncogenic effect of ZFPM2-AS1 in SCLC progression, indicating it may be a therapeutic target for SCLC.

lncRNA SNHG3 acts as a novel Tumor Suppressor and regulates Tumor Proliferation and Metastasis via AKT/mTOR/ERK pathway in Papillary Thyroid Carcinoma

The incidence of papillary thyroid carcinoma (PTC) has been increased rapidly in recent decades. Long noncoding RNAs (lncRNA) are a class of non-protein-coding transcripts and play critical roles in regulating gene expression and influence biological behaviors of multiple cancers, including PTC. Here, we discovered that lncRNA SNHG3 was significantly downregulated in PTC tissues and cell lines, the expression of SNHG3 was negatively correlated with the TNM stage and poor prognosis of PTC patients. Functional studies illustrated that the depletion of SNHG3 via CRISPR/Cas9 technology promoted the proliferation, migration and invasion abilities of PTC cells. Tumor xenograft models confirmed the tumor-promoting role of silenced SNHG3 in vivo. Further mechanistic analyses revealed that knockout of SNHG3 activated the AKT/mTOR/ERK pathway in PTC cell lines and the mTOR inhibitor AZD8055 abrogated the tumor-promoting effect induced by SNHG3 inhibition. Taken together, our findings identified a lncRNA SNHG3 that functions its tumor-suppressor role during PTC development and SNHG3 might serve as a promising candidate for target therapy of PTC.

The lncRNA SNHG3 accelerates papillary thyroid carcinoma progression via the miR-214-3p/PSMD10 axis

Small nucleolar RNA host gene 3 (SNHG3) is a long noncoding RNA (lncRNA), which is known to promote oncogenesis in many cancers but its role in human papillary thyroid carcinoma (PTC) remains poorly understood. We therefore assessed SNHG3 expression in PTC tissues via quantitative reverse transcription polymerase chain reaction. We additionally knocked down SNHG3 in PTC cells using short-hairpin RNAs (shRNAs) to explore its functional roles in PTC. The ability of SNHG3 to bind to specific microRNAs (miRNAs) was predicted using a bioinformatics tool, and this binding was confirmed via dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. We then used a tumor xenograft model to assess the relevance of SNHG3 in vivo. We determined SNHG3 expression to be elevated in PTC tissues relative to controls, with advanced tumor-node-metastasis stage and lymph node metastasis being associated with this expression. Knocking down SNHG3 significantly reduced in vitro PTC cell migration, invasion, proliferation, and colony formation, and it further slowed the growth of tumors in vivo. We found that SNHG3 could bind to miR-214-3p as a competing endogenous RNA (ceRNA) for this miRNA, thereby regulating proteasome 26S subunit non-ATPase 10 (PSMD10) expression, a miR-214-3p target. These results thus indicate that SNHG3 is an oncogenic lncRNA in PTC, acting at least in part via the miR-214-3p/PSMD10 axis.

DDX11-AS1 contributes to osteosarcoma progression via stabilizing DDX11

Increasing evidence has uncovered that long noncoding RNAs (lncRNAs) play extremely important roles in numerous steps of gene regulation concerning the progression of tumors. Defined as a kind of lncRNA, DDX11-AS1 has been considered to be closely related to the tumorigenesis of malignancies. Nevertheless, the underlying regulatory role of it in osteosarcoma remains to be analyzed and elucidated. In this research, a dramatically upregulated expression of DDX11-AS1 was detected in osteosarcoma cells. Loss-of-function assays revealed that decreased expression of DDX11-AS1 impaired osteosarcoma cell proliferation, metastasis as well as epithelial-mesenchymal transition (EMT) process. Afterwards, molecular mechanism tests validated that DDX11-AS1 could sponge miR-873-5p to upregulate DDX11 expression in osteosarcoma. Additionally, functional tests delineated that upregulation of miR-873-5p inhibited cell proliferation, metastasis as well as EMT process in osteosarcoma progression. Further, DDX11-AS1 was verified to regulate the mRNA stability of DDX11 through binding with IGF2BP2 in osteosarcoma. Final rescue tests in vitro and in vivo further elucidated that DDX11 overexpression could reversed the DDX11-AS1 downregulation-mediated effect on osteosarcoma progression. To sum up, DDX11-AS1 contributes to osteosarcoma progression via stabilizing DDX11.

The role of long non-coding RNAs in the pathogenesis of thyroid cancer

Long noncoding RNAs (lncRNAs) as prominent regulators of gene expression are involved in different layers of expression regulation. These transcripts participate in carcinogenesis of several human malignancies including thyroid cancer. Availability of high throughput techniques such as RNA sequencing and microarray has facilitated identification of lncRNAs whose dysregulation affect tumorigenesis process. Moreover, assessment of differentially expressed lncRNAs between resistant and sensitive cells has led to recognition of biomarkers for therapeutic response. One elucidated aspect of lncRNAs functions is their role in sponging miRNAs. Several miRNA-lncRNA-mRNA triplets have been recognized till now. Any of these triplets is a putative target of interfering with the evolution of cancer. In the current study, we have summarized recent data in the fields of biology of lncRNAs, their role in thyroid cancer and their potential as biomarker or treatment target.

Long Non-coding RNA PVT1 as a Prognostic and Therapeutic Target in Pediatric Cancer

In recent decades, biomedical research has focused on understanding the functionality of the human translated genome, which represents a minor part of all genetic information transcribed from the human genome. However, researchers have become aware of the importance of non-coding RNA species that constitute the vast majority of the transcriptome. In addition to their crucial role in tissue development and homeostasis, mounting evidence shows non-coding RNA to be deregulated and functionally contributing to the development and progression of different types of human disease including cancer both in adults and children. Small non-coding RNAs (i.e., microRNA) are in the vanguard of clinical research which revealed that RNA could be used as disease biomarkers or new therapeutic targets. Furthermore, many more expectations have been raised for long non-coding RNAs, by far the largest fraction of non-coding transcripts, and still fewer findings have been translated into clinical applications. In this review, we center on PVT1, a large and complex long non-coding RNA that usually confers oncogenic properties on different tumor types. We focus on the compilation of early advances in the field of pediatric tumors which often lags behind clinical improvements in adult tumors, and provide a rationale to continue studying PVT1 as a possible functional contributor to pediatric malignancies and as a potential prognostic marker or therapeutic target.

Long non-coding RNA PVT1 interacts with MYC and its downstream molecules to synergistically promote tumorigenesis

Numerous studies have shown that non-coding RNAs play crucial roles in the development and progression of various tumor cells. Plasmacytoma variant translocation 1 (PVT1) mainly encodes a long non-coding RNA (lncRNA) and is located on chromosome 8q24.21, which constitutes a fragile site for genetic aberrations. PVT1 is well-known for its interaction with its neighbor MYC, which is a qualified oncogene that plays a vital role in tumorigenesis. In the past several decades, increasing attention has been paid to the interaction mechanism between PVT1 and MYC, which will benefit the clinical treatment and prognosis of patients. In this review, we summarize the coamplification of PVT1 and MYC in cancer, the positive feedback mechanism, and the latest promoter competition mechanism of PVT1 and MYC, as well as how PVT1 participates in the downstream signaling pathway of c-Myc by regulating key molecules. We also briefly describe the treatment prospects and research directions of PVT1 and MYC.

Chemoresistance Mediated by ceRNA Networks Associated With the PVT1 Locus

Competitive endogenous RNA (ceRNA) networks have emerged as critical regulators of carcinogenesis. Their activity is mediated by various non-coding RNAs (ncRNAs), including long non-coding RNAs and microRNAs, which competitively bind to targets, thereby modulating gene expression and activity of proteins. Of particular interest, ncRNAs encoded by the 8q24 chromosomal region are associated with the development and progression of several human cancers, most prominently lncPVT1. Chemoresistance presents a significant obstacle in the treatment of cancer and is associated with dysregulation of normal cell processes, including abnormal proliferation, differentiation, and epithelial-mesenchymal transition. CeRNA networks have been shown to regulate these processes via both direct sponging/repression and epigenetic mechanisms. Here we present a review of recent literature examining the contribution of ncRNAs encoded by the PVT1 locus and their associated ceRNA networks to the development of resistance to common chemotherapeutic agents used to treat human cancers.

Knockdown of long noncoding RNA PVT1 suppresses cell proliferation and invasion of colorectal cancer via upregulation of microRNA-214-3p

Long noncoding RNAs (lncRNAs) have been reported to be involved in the occurrence and tumorigenesis of numerous malignant cancers. Microarray expression profiles were used to screen colorectal cancer (CRC)-related differentially expressed genes and lncRNAs, which revealed that insulin receptor substrate 1 (IRS1) and lncRNA plasmacytoma variant translocation 1 (PVT1) were highly expressed in CRC. This study aimed to investigate the regulatory role of lncRNA PVT1 in CRC. Subcellular localization detected by fluorescence in situ hybridization identified that lncRNA PVT1 was primarily located in the cytoplasm. The interaction between lncRNA PVT1 and microRNA-214-3p (miR-214-3p) and IRS1 was predicted using the RNA22 website. Next the dual luciferase reporter gene assay, RNA pull-down, and RNA immunoprecipitation assays verified lncRNA PVT1 to be a competitive endogenous RNA (ceRNA) against miR-214-3p, and IRS1 was found to be a target of miR-214-3p. The expression pattern of lncRNA PVT1, miR-214-3p, IRS1, phosphoinositide 3-kinase (PI3K), and Akt was characterized in response to lncRNA PVT1 silencing or miR-214-3p upregulation. Meanwhile, their regulatory effects on cell proliferation, invasion, and apoptosis were detected in CRC cells. With increased levels of miR-214-3p and decreased levels of lncRNA PVT1 in CRC cells, the expression of phosphatidylinositol 3-kinase, putative (PI3K) and Akt was reduced, and consequently, the cell apoptosis was stimulated and cell proliferation and invasion were suppressed. All in all, lncRNA PVT1 competitively binds to miR-214-3p to upregulate the expression of IRS1 thus activating the PI3K/Akt signaling pathway, thus accelerating CRC progression. This study suggests that lncRNA PVT1 might be a potential target of therapeutic strategies for CRC treatment.NEW & NOTEWORTHY This study mainly suggests that long noncoding (lnc)RNA plasmacytoma variant translocation 1 (PVT1) is a downregulated lncRNA in colorectal cancer (CRC), accelerating CRC progression. Strikingly, lncRNA PVT1 acts as a competitive endogenous RNA against microRNA (miR)-214-3p, whereas miR-214-3p targets insulin receptor substrate 1, which draws a comprehensive picture of the potential molecular mechanisms of lncRNA PVT1 in CRC.

Long noncoding RNA HOTTIP is associated with male infertility and promotes testicular embryonal carcinoma cell proliferation

Background

It has been proposed that lncRNAs, widely transcribed from genomes, play pivotal regulatory roles in a variety of biological processes, but their function in regulating spermatogenesis in human males is rarely reported.

Methods

QRT‐PCR was adopted to detect HOTTIP expression level in testicular tissues from hypospermatogenesis (Hypo) patients or controls. The proliferation levels of NT2 and 293T were measured via CCK‐8 and EdU detection. Meanwhile, luciferase reporter gene assay and bioinformatics analysis were carried out to identify a target of HOTTIP. Additionally, the underlying mechanism of HOTTIP’s function was investigated using western blotting and RIP analysis.

Results

The research results manifested that the expression of HOTTIP in testicular tissues from Hypo patients was prominently reduced in comparison with that in control testicular tissues. Interestingly, it was noted that HOTTIP exhibited a high expression in testicular embryonal carcinoma cell line NT2 compared with that in normal control cell line 293T. It was denoted in cell function evaluation that cell proliferation was impeded by downregulated HOTTIP but evidently stimulated by overexpressed HOTTIP. Moreover, HOTTIP was capable of positively modulating HOXA13 expression via the competitive binding to miR‐128‐3p.

Conclusion

Therefore, HOTTIP acting as ceRNAs to promote testicular embryonal carcinoma cell proliferation.

PVT1 Promotes Cancer Progression via MicroRNAs

Non-coding RNA (ncRNA) plays a regulatory role in a variety of cellular activities. And long non-coding RNA (lncRNA) is one of the important kinds of ncRNA. Previous studies have shown that various lncRNAs are involved in the progression of cancer. LncRNA plasmacytoma variant translocation 1 (PVT1) is a newly discovered oncogenic factor that has been confirmed to be overexpressed in many cancer cells. Moreover, the role of PVT1 in cancer development is closely linked to microRNAs (miRNAs). PVT1 can act as a "sponge" for miRNAs to inhibit their activities, thereby affecting proliferation, invasion, and angiogenesis of cancer. In addition, PVT1 itself can be spliced and processed into several miRNAs such as miR-1204 and miR-1207, which can also regulate the development of cancer. This review summarizes various pathways through which PVT1 regulates the progression of cancer via miRNAs. We also propose additional regulatory mechanisms of PVT1 and their potential clinical applications.

Long noncoding RNA PVT1: A highly dysregulated gene in malignancy

Recent studies have verified the contribution of several long noncoding RNAs (lncRNAs) in the carcinogenesis. Among the highly acknowledged lncRNAs is the human homolog of the plasmacytoma variant translocation gene, which is called PVT1. PVT1 resides near Myc oncogene and regulates the oncogenic process through modulation of several signaling pathways, such as TGF-β, Wnt/ β-catenin, PI3K/AKT, and mTOR pathways. This lncRNA has a circular form as well. Expression analyses and functional studies have appraised the oncogenic roles of PVT1 and circPVT1. Experiments in several cancer cell lines have shown that PVT1 silencing suppresses cancer cell proliferation, whereas its overexpression has the opposite effect. Its silencing has led to the accumulation of cells in the G0/G1 phase and diminished the number of cells in the S phase. Moreover, genome-wide association studies have signified the role of single nucleotide polymorphisms of this lncRNA in conferring risk of lymphoma in different populations. In the current study, we have summarized recent data about the role of PVT1 and circPVT1 in the carcinogenesis process.

Long non-coding RNA H19 knockdown inhibits the cell viability and promotes apoptosis of thyroid cancer cells through regulating the PI3K/AKT pathway

Certain long non-coding (lnc)RNAs have been reported to serve important roles in the genesis and progression of thyroid cancer (TC). Recent studies have demonstrated that the expression of lncRNA H19 is upregulated in TC tissues; however, knowledge of the associated molecular mechanisms is limited. Therefore, the present study aimed to clarify the roles of H19 in TC. The mRNA expression of lncRNA H19 in TC tissues was determined using reverse transcription-quantitative polymerase chain reaction analysis, and the effects of H19 knockdown on cell viability and apoptosis in vitro were assessed using MTT and flow cytometric assays, respectively. Finally, the signaling pathways involved in the effects of H19 were examined. The results indicated that H19 was upregulated in TC tissues. Silencing of H19 inhibited the cell viability and promoted apoptosis of FTC-133 and TPC-1 TC cells, accompanied by an increased expression of B-cell lymphoma 2 (Bcl-2)-associated X protein and caspase 3, and repressed expression of Bcl-2. The results of western blot analysis suggested that the levels of phosphorylated phosphoinositide-3 kinase (PI3K) and phosphorylated AKT were attenuated by H19 silencing. These results suggest that lncRNA H19 exerts an oncogenic function in TC, in part through the PI3K/AKT pathway.

Knockdown of circPVT1 inhibits progression of papillary thyroid carcinoma by sponging miR-126

Background: Papillary thyroid carcinoma (PTC) is the most common thyroid cancer. Recent studies have reported that circular RNAs (circRNAs) play essential roles in human cancers, including PTC. However, the roles of circRNA plasmacytoma variant translocation 1 (PVT1) in PTC progression and its potential mechanism remain largely unknown. Methods: The expressions of circPVT1 and microRNA-126 (miR-126) were measured in PTC tissues and cells by quantitative real-time polymerase chain reaction (qRT-PCR). Cell viability, apoptosis, migration and invasion were detected in PTC cells by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), flow cytometry, Western blot or trans-well assays, respectively. The interaction between circPVT1 and miR-126 was explored by bioinformatics analysis, luciferase activity assay and RNA immunoprecipitation. A mouse xenograft model was established to investigate the role of circPVT1 in PTC progression in vivo. Results: High expression of circPVT1 was shown in PTC tissues and cells and was associated with poor outcomes of patients. Knockdown of circPVT1 suppressed viability, migration and invasion but induced apoptosis in PTC cells. miR-126 was bound to circPVT1 and reduced in PTC tissues and cells. Moreover, inhibition of miR-126 reversed the regulatory effect of the circPVT1 interference on viability, apoptosis, migration and invasion in PTC cells. Besides, circPVT1 knockdown attenuated tumor growth via up-regulating miR-126 in vivo. Conclusion: CircPVT1 knockdown inhibited PTC progression by sponging miR-126. This may indicate circPVT1 as a novel target for treatment of PTC.

Papillary thyroid carcinoma (PTC) is the most common thyroid cancer. Recent studies have reported that circular RNAs (circRNAs) play essential roles in human cancers, including PTC.

BRD4 promotes the stemness of gastric cancer cells via attenuating miR-216a-3p-mediated inhibition of Wnt/β-catenin signaling

The bromodomain and extra-terminal domain (BET) protein BRD4 is emerging as a potential target for cancer therapy. However, BRD4 roles in regulating the stemness of gastric cancer cells are unclear. Here, we demonstrated that BRD4 expression was significantly increased in gastric cancer tissues, cell spheroids, and BRD4 knockdown attenuated the stemness of gastric cancer cells characterized as the decrease of stemness markers expression, capacity of cells spheroids formation and ALDH1 activity. Importantly, BRD4 expression was negatively correlated with overall survival, first progression survival and post progression survival of gastric cancer patients. Mechanistic investigations revealed that miR-216a-3p was the most remarkably upregulated miRNA in response to BRD4 knockdown and Wnt/β-catenin signaling was necessary for BRD4-mediated promotion on the stemness of gastric cancer cells. Additionally, BRD4 directly bound to the promoter and promoted the methylation level of MIR216A promoter, thus decreasing miR-216a-3p level. Notably, Wnt3a was identified as the direct target of miR-216a-3p in gastric cancer cells. Therefore, our results defined a BRD4/miR-216a-3p/Wnt/β-catenin pathway in regulating the stemness of gastric cancer cells.

Knockdown of lncRNA PVT1 inhibits retinoblastoma progression by sponging miR-488-3p

Emerging evidence suggests that long non-coding RNAs (lncRNAs) play a regulatory role in the pathogenesis and progression of retinoblastoma (RB). lncRNA plasmacytoma variant translocation 1 (PVT1) is highly expressed in a plenty of tumors, and is believed to serve as an oncogene. However, the expression, roles, and action mechanisms of PVT1 in the carcinogenesis and progression of RB are still largely unknown. In this study, we found that PVT1 was upregulated in RB tissues and cell lines. PVT1 levels correlated with optic nerve invasion, and intraocular international retinoblastoma classify (IIRC) stage. In addition, the results demonstrated that patients with RB who showed higher expression of PVT1 had worse overall survivals. In WERI-Rb1 and Y79 cells, PVT1 silencing significantly inhibited cell proliferation, migration, invasion, and cell cycle progression and induced cell apoptosis in vitro. Moreover, in vivo xenograft assay indicated that PVT1 knockdown suppressed the tumor volume and tumor weight. The analysis of the mechanisms of action revealed that the reduction of PVT1 inhibited the expression of notch2 by upregulating miR-488-3p. In general, our results demonstrated that PVT1 may be a novel biomarker for prognosis and a new target for the treatment of RB.

Construction of a long non‑coding RNA-mediated competitive endogenous RNA network reveals global patterns and regulatory markers in gestational diabetes

Gestational diabetes mellitus (GDM) is a common disease affecting pregnant women. Recent studies have suggested that competing endogenous RNAs (ceRNAs), which compete with long non‑coding RNAs (lncRNAs) for microRNA (miRNA or miR) binding and indirectly regulate miRNA targets through competing interactions, play a critical role in disease. In this study, we present a computationally integrated approach with which to construct a lncRNA‑mediated ceRNA network (LCEN) in GDM by integrating RNA interactions and expression data. lncRNAs exhibited specific features and played critical roles in GDM‑associated LCEN. The construction of a global functional score profile revealed that ceRNAs had a high activity in GDM. We extracted several ceRNA modules and demonstrated that these modules had increased close interactions. We further discovered that these ceRNA modules may be utilized as specific and effective circulating biomarkers for GDM. Finally, functional analyses demonstrated that the GDM‑associated ceRNAs participated in the regulation of irisin and the thyroid hormone signaling pathway. It was suggested that there were close associations between the thyroid hormone and GDM. Collectively, ceRNAs may accelerate biomarker discovery and therapeutic development in GDM.

DNA copy number gain-mediated lncRNA LINC01061 upregulation predicts poor prognosis and promotes papillary thyroid cancer progression

Several DNA copy number amplifications (CNAs) have been reported in papillary thyroid cancer (PTC). However, the functional role of CNAs in PTC remains very unclear. And whether there is a correlation between long noncoding RNA (lncRNA) and CNA requires to be explored. Here, we identified a novel lncRNA LINC01061. The genomic copy number of LINC01061 is amplified, which leads to its elevated expression level in PTC tissues. Moreover, increased level of LINC01061 was correlated with aggressive clinicopathological characteristics. Functional study indicated that LINC01061 silence significantly inhibited the proliferation, cell-cycle and invasion of PTC cells in vitro and tumor growth in vivo. Mechanistically, we showed that LINC01061 interacted with miR-4316 to promote E2F6 expression. The expression of miR-4316 was downregulated in PTC tissues while that of E2F6 was upregulated. Through rescue assay, we demonstrated that LINC01061 promoted PTC cell proliferation, cell-cycle progression and invasion by regulating miR-4316/E2F6 signaling pathway. In conclusion, our research indicated that LINC01061 might be a target for PTC therapy.

Active Surveillance for Papillary Thyroid Microcarcinoma: Challenges and Prospects

Active surveillance (AS) can be considered as an alternative to immediate surgery in low-risk papillary thyroid microcarcinoma (PTMC) without clinically apparent lymph nodes, gross extrathyroidal extension (ETE), and/or distant metastasis according to American Thyroid Association. However, in the past AS has been controversial, as evidence supporting AS in the management of PTMC was scarce. The most prominent of these controversies included, the limited accuracy and utility of ultrasound (US) in the detection of ETE, malignant lymph node involvement or the advent of novel lymph node malignancy during AS, and disease progression. We summarized publications and indicated: (1) US, performer-dependent, could not accurately diagnose gross ETE or malignant lymph node involvement in PTMC. However, the combination of computed tomography and US provided more accurate diagnostic performance, especially in terms of selection sensitivity. (2) Compared to immediate surgery patients, low-risk PTMC patients had a slightly higher rate of lymph node metastases (LNM), although the overall rate for both groups remained low. (3) Recent advances in the sensitivity and specificity of imaging and incorporation of diagnostic biomarkers have significantly improved confidence in the ability to differentiate indolent vs. aggressive PTMCs. Our paper reviewed current imagings and biomarkers with initial promise to help select AS candidates more safely and effectively. These challenges and prospects are important areas for future research to promote AS in PTMC.