The long non-coding RNA SNHG3 functions as a competing endogenous RNA to promote malignant development of colorectal cancer

Exosomal Lipids in Cancer Progression and Metastasis

BACKGROUND

Metastasis is the primary cause of cancer mortality. It is responsible for 90% of all cancer-related deaths. Intercellular communication is a crucial feature underlying cancer metastasis and progression. Cancerous tumors secrete membrane-derived small extracellular vesicles (30-150 nm) into their extracellular milieu. These tiny organelles, known as exosomes, facilitate intercellular communication by transferring bioactive molecules. These exosomes harbor different cargos, such as proteins, nucleic acids, and lipids, that mediate multifaceted functions in various oncogenic processes. Of note, the amount of lipids in exosomes is multifold higher than that of other cargos. Most studies have investigated the role of exosomes' protein and nucleic acid content in various oncogenic processes, while the role of lipid cargo in cancer pathophysiology remains largely obscure.

MATERIALS AND METHODS

We conducted an extensive literature review on the role of exosomes and lipids in cancer progression, specifically addressing the topic of exosomal lipids and their involvement in cancer metastasis and progression.

CONCLUSIONS

This review aims to shed light on the lipid contents of exosomes in cancer metastasis. In this context, the role of exosomal lipids in signaling pathways, immunomodulation, and energy production for cancer cell survival provides insights into overcoming cancer progression and metastasis.

Identification of MYC and STAT3 for early diagnosis based on the long noncoding RNA-mRNA network and bioinformatics in colorectal cancer

Background

Colorectal cancer (CRC) ranks among the top three cancers globally in both incidence and mortality, posing a significant public health challenge. Most CRC cases are diagnosed at intermediate to advanced stages, and reliable biomarkers for early detection are lacking. Long non-coding RNAs (lncRNAs) have been implicated in various cancers, including CRC, playing key roles in tumor development, progression, and prognosis.

Methods

A comprehensive search of the PubMed database was conducted to identify relevant studies on the early diagnosis of CRC. Bioinformatics analysis was performed to explore lncRNA-mRNA networks, leading to the identification of five potential blood biomarkers. Expression analysis was carried out using the GEPIA and GEO online databases, focusing on MYC and STAT3. Differential expression between normal and CRC tissues was assessed, followed by Receiver Operating Characteristic (ROC) analysis to evaluate the diagnostic potential of these markers. Quantitative Real-Time PCR (qRT-PCR) was performed to validate MYC and STAT3 expression levels, and findings were further confirmed using the Human Protein Atlas (HPA) database.

Results

Database analysis revealed significant differential expression of MYC and STAT3 between normal and CRC tissues. ROC analysis demonstrated the diagnostic potential of these markers. qRT-PCR validation confirmed the differential expression patterns observed in the databases. Validation through the HPA database further supported these findings, confirming the potential of MYC and STAT3 as diagnostic biomarkers for CRC.

Conclusion

Our results suggest that MYC and STAT3 are promising diagnostic biomarkers for CRC, offering new insights into its pathophysiology and potential for targeted therapies.

The role of the ceRNA network mediated by lncRNA SNHG3 in the progression of cancer

BACKGROUND

Long non-coding RNAs (lncRNAs) are a distinct class of RNAs with longer than 200 base pairs that are not translated into proteins. Small Nucleolar RNA Host Gene 3 (SNHG3) is a lncRNA and frequently dysregulated in various human cancers.

OBJECTIVE

This review provides a comprehensive analysis of current research on lncRNA SNHG3, focusing on its role within the competitive endogenous RNA (ceRNA) network and its implications in cancer.

METHODS

A systematic literature review was conducted using PubMed up to October 2023. The search strategy included keywords such as "lncRNA SNHG3", "competitive endogenous RNA", "cancer", and related terms. Studies were selected based on relevance to SNHG3's involvement in cancer pathogenesis and progression.

RESULTS

Disruptions in the ceRNA network involving lncRNA SNHG3 can impair normal cell growth and differentiation, significantly contributing to disease pathogenesis, particularly cancer. This review highlights SNHG3's substantial impact on various cancer processes and its potential as a diagnostic and therapeutic tool for aggressive cancers.

CONCLUSION

The findings underscore SNHG3's pivotal role in cancer prevention, diagnosis, and treatment, laying a foundation for future research in cancer management. Insights from this review emphasize the necessity for further exploration and development of SNHG3-based diagnostic and therapeutic strategies.

Reciprocal interactions between lncRNAs and MYC in colorectal cancer: partners in crime

Proto-oncogenic MYC is frequently dysregulated in colorectal cancer (CRC). In the past decades, long noncoding RNAs (lncRNAs) have emerged as important regulators in cancers, acting as scaffolds, molecular decoys, post-transcriptional regulators, and others. Interestingly, lncRNAs are able to control MYC expression both at transcriptional and post-transcriptional levels. It is suggested that the reciprocal interaction of MYC and lncRNAs often occurs in CRC. MYC can affect the cell fate by promoting or inhibiting the transcription of some lncRNAs. At the same time, some lncRNAs can also affect MYC expression or transcriptional activity, and in turn decide the cell fate. In this review we summarized the current knowledge about the MYC and lncRNA axis, focusing on its mutual regulation, roles in CRC, and proposed potential therapeutic prospects for CRC treatment.

Functional role of lncRNAs in gastrointestinal malignancies: the peculiar case of small nucleolar RNA host gene family

Long noncoding RNAs (lncRNAs) play crucial roles in normal physiology and are often de-regulated in disease states such as cancer. Recently, a class of lncRNAs referred to as the small nucleolar RNA host gene (SNHG) family have emerged as important players in tumourigenesis. Here, we discuss new findings describing the role of SNHGs in gastrointestinal tumours and summarize the three main functions by which these lncRNAs promote carcinogenesis, namely: competing with endogenous RNAs, modulating protein function, and regulating epigenetic marking. Furthermore, we discuss how SNHGs participate in different hallmarks of cancer, and how this class of lncRNAs may serve as potential biomarkers in cancer diagnosis and therapy.

MicroRNA-183 cluster: a promising biomarker and therapeutic target in gastrointestinal malignancies

Small non-coding RNAs (microRNA, miR), powerful epigenetic regulators, were found involved in the regulation of most biological functions via post-translational inhibition of protein expression. Increased expression of pro-oncogenic miRs (known as miR cancer biomarkers) and inhibition of pro-apoptotic miR expression have been demonstrated in different tumors. The recently identified miR-183 was found implicated in gastrointestinal tumor metabolism regulation. Elevated miR-183 expression and cancer-promoting effects were reported in esophageal and colorectal cancers, which was partially contradicted by controversial data observed in gastric cancers. Anti-cancer effect of miR-183 in gastric cancer cells was associated with the Bim-1 and Ezrin genes regulation. Many studies indicated that miR-183 can inhibit tumor suppressor genes in most cell lines, promoting tumor cell proliferation and migration. Increased miR-183 level results in the downregulation of FOXO1, PDCD4, and other tumor suppressor genes in gastrointestinal tumor cells. MiR-183 also influences the signaling of PI3K/AKT/mTOR, Wnt/β-catenin, and Bcl-2/p53 signaling pathways. Mir-183 inhibits apoptosis and autophagy, and promotes epithelial-to-mesenchymal transition, cancer cell proliferation, and migration. Accordingly, gastrointestinal cancer occurrence, development of chemoradiotherapy resistance, recurrence/metastasis, and prognosis were associated with miR-183 expression. The current study assessed reported miR-183 functions and signaling, providing new insights for the diagnosis and treatment of gastrointestinal malignancies.

SNHG3/WISP2 Axis Promotes Hela Cell Migration and Invasion via Activating Wnt/β-Catenin Signaling

BACKGROUND/AIM

Cervical cancer (CC) poses a significant threat to women's health and has a relatively poor prognosis due to local invasion and metastasis. It is, therefore, crucial to elucidate the molecular mechanisms of CC metastasis. SNHG3 has been implicated in various tumor metastasis processes, but its involvement in CC has not been thoroughly studied. Our study aimed to investigate the role of SNHG3 in metastasis and elucidate its underlying mechanisms in CC.

MATERIALS AND METHODS

LncRNA SNHG3 expression in CC tissues was analyzed using TCGA and GSE27469 databases. Normal cervical epithelial cells and CC cell lines were used to detect mRNA expression of SNHG3 via quantitative reverse transcription polymerase chain reaction (qRT-PCR). With RNA interference (RNAi) technology, antisense oligonucleotides (ASO) can act on HeLa cells to knockdown target gene expression. The influence of SNHG3 on cell migration and invasion were determined by wound healing and transwell assays. Transcriptome sequencing (RNA-seq) was used to seek abnormally expressed genes between SNHG3 knockdown cells and control cells. The expressions of epithelial-mesenchymal transition (EMT) and Wnt/β-catenin signaling related proteins were detected using western blot.

RESULTS

SNHG3 was obviously up-regulated in CC tissues and cell lines, and ectopic expression of SNHG3 was associated with lymph node metastasis of CC. Knockdown of SNHG3 significantly inhibited cell migration and invasion in CC. Further molecular mechanism studies showed that SNHG3 knockdown could down-regulate the expression of WNT1 Inducible Signaling Pathway Protein 2 (WISP2) so as to inhibit the activation of the Wnt/β-catenin signaling pathway, and regulated the expression of EMT-related markers, that promoted the protein expression of E-cadherin, as well as decreased the expression of N-cadherin and vimentin.

CONCLUSION

SNHG3 appears to exert a pro-metastatic effect in CC, as evidenced by inhibition of cell migration and invasion upon SNHG3 knockdown. EMT also appears to be attenuated. Of interest is the down-regulation of WISP2 following SNHG3 knockdown leads to the inactivation of the Wnt/β-catenin signaling pathway.

A comprehensive insight into the role of small nucleolar RNAs (snoRNAs) and SNHGs in human cancers

Long non-coding RNAs (lncRNAs), which comprise most non-coding RNAs (ncRNAs), have recently become a focus of cancer research. How many functional ncRNAs exist is still a matter of debate. Although insufficient evidence supports that most lncRNAs function as transcriptional by-products, it is widely known that an increasing number of lncRNAs play essential roles in cells. Small nucleolar RNAs (snoRNAs), 60-300 nucleotides in length, have been better studied than long non-coding RNAs (lncRNAs) and are predominantly present in the nucleolus. Most snoRNAs are encoded in introns of protein- and non-protein-coding genes called small nucleolar RNA host genes (SNHGs). In this article, we explore the biology and characteristics of SNHGs and their role in developing human malignancies. In addition, we provide an update on the ability of these snoRNAs to serve as prognostic and diagnostic variables in various forms of cancer.

Downregulation of miR-182-5p by NFIB promotes NAD+ salvage synthesis in colorectal cancer by targeting NAMPT

Nuclear factor I B (NFIB) plays an important role in tumors. Our previous study found that NFIB can promote colorectal cancer (CRC) cell proliferation in acidic environments. However, its biological functions and the underlying mechanism in CRC are incompletely understood. Nicotinamide adenine dinucleotide (NAD+) effectively affects cancer cell proliferation. Nevertheless, the regulatory mechanism of NAD+ synthesis in cancer remains to be elucidated. Here we show NFIB promotes CRC proliferation in vitro and growth in vivo, and down-regulation of NFIB can reduce the level of NAD+. In addition, supplementation of NAD+ precursor NMN can recapture cell proliferation in CRC cells with NFIB knockdown. Mechanistically, we identified that NFIB promotes CRC cell proliferation by inhibiting miRNA-182-5p targeting and binding to NAMPT, the NAD+ salvage synthetic rate-limiting enzyme. Our results delineate a combination of high expression of NFIB and NAMPT predicted a clinical poorest prognosis. This work provides potential therapeutic targets for CRC treatment.

SNHG3 regulates NEIL3 via transcription factor E2F1 to mediate malignant proliferation of hepatocellular carcinoma

The involvement of small nucleolar RNA host gene 3 (SNHG3) in cancer regulation has been reported. This study attempted to deeply investigate the molecular regulatory mechanism of SNHG3 on malignant progression of hepatocellular carcinoma (HCC). According to TCGA analysis, high SNHG3 expression was a risk factor for poor prognosis of HCC patients. Therefore, we further detected the mRNA level of SNHG3 in HCC tissue and cells. It was found that SNHG3 was upregulated in HCC tissue and cells. Afterwards, CCK-8 and flow cytometry assays further proved that silencing SNHG3 inhibited HCC cell proliferation while inducing cell apoptosis and G0/G1 phase arrest. It was also attested in vivo experiments that silencing SNHG3 could reduce the volume and weight of tumors and downregulate the Ki-67 expression to suppress HCC tumor growth. Next, it was discovered that SNHG3 increased the binding of E2F1 and NEIL3 promoter region, thereby activating the transcription feature of NEIL3. Lastly, rescue assays indicated that NEIL3 participated in SNHG3-mediated HCC cell cycle, apoptosis and proliferation. All in all, this study revealed the specific regulatory mechanism of SNHG3 in HCC to enable SNHG3 a hopeful marker for HCC diagnosis and treatment.

Enabling factor for cancer hallmark acquisition: Small nucleolar RNA host gene 17

The role of long non-coding RNA (lncRNA) in human tumors has gradually received increasing attention in recent years. Particularly, the different functions of lncRNAs in different subcellular localizations have been widely investigated. The upregulation of lncRNA small nucleolar RNA host gene 17 (SNHG17) has been observed in various human tumors. Growing evidence has proved that SNHG17 plays a tumor-promoting role in tumorigenesis and development. This paper describes the molecular mechanisms by which SNHG17 contributes to tumor formation and development. The different functions of SNHG17 in various subcellular localizations are also emphasized: its function in the cytoplasm as a competing endogenous RNA (ceRNA), its action in the nucleus as a transcriptional coactivator, and its function through the polycomb repressive complex 2 (PRC2)-dependent epigenetic modifications that regulate transcriptional processes. Finally, the correlation between SNHG17 and human tumors is summarized. Its potential as a novel prognostic and diagnostic biomarker for cancer is explored especially.

Systematic pan-cancer analysis on the expression and role of regulator of chromatin condensation 1/small nucleolar RNA host gene 3/small nucleolar RNA host gene 12

Regulator of chromatin condensation 1 (RCC1) is the major guanine nucleotide exchange factor of RAN GTPase, which plays a key role in various biological processes such as cell cycle and DNA damage repair. Small nucleolar RNA host gene 3 (SNHG3) and small nucleolar RNA host gene12 are long-stranded non-coding RNAs (lncRNAs) and are located on chromatin very close to the sequence of Regulator of chromatin condensation 1. Many studies have shown that they are aberrantly expressed in tumor tissues and can affect the proliferation and viability of cancer cells. Although the effects of Regulator of chromatin condensation 1/small nucleolar RNA host gene 3/small nucleolar RNA host gene12 on cellular activity have been reported, respectively, their overall analysis on the pan-cancer level has not been performed. Here, we performed a comprehensive analysis of Regulator of chromatin condensation 1/small nucleolar RNA host gene 3/small nucleolar RNA host gene12 in 33 cancers through the Cancer Genome Atlas and Gene Expression Database. The results showed that Regulator of chromatin condensation 1/small nucleolar RNA host gene 3/small nucleolar RNA host gene12 were highly expressed in a variety of tumor tissues compared to normal tissues. The expression of Regulator of chromatin condensation 1/small nucleolar RNA host gene 3/small nucleolar RNA host gene12 in BRCA, LGG and LIHC was associated with TP53 mutations. In addition, Regulator of chromatin condensation 1/small nucleolar RNA host gene 3/small nucleolar RNA host gene12 expression was closely associated with the prognosis of patients with multiple tumors. Immunocorrelation analysis indicated that Regulator of chromatin condensation 1/small nucleolar RNA host gene 3/small nucleolar RNA host gene12 showed a correlation with multiple immune cell infiltration. The results of enrichment analysis suggested that Regulator of chromatin condensation 1/small nucleolar RNA host gene 3/small nucleolar RNA host gene12 was involved in the regulation of cell cycle, apoptosis and other pathways. We found that these effects were mainly mediated by Regulator of chromatin condensation 1, while the trend of small nucleolar RNA host gene 3/small nucleolar RNA host gene12 regulation was also consistent with regulator of chromatin condensation 1. The important role played by Regulator of chromatin condensation 1 in tumor diseases was further corroborated by the study of adjacent lncRNAs.These findings provide new and comprehensive insights into the role of Regulator of chromatin condensation 1/small nucleolar RNA host gene 3/small nucleolar RNA host gene12 in tumor development and show their potential as clinical monitoring and therapy.

Cancer-associated fibroblasts-derived extracellular vesicles carrying lncRNA SNHG3 facilitate colorectal cancer cell proliferation via the miR-34b-5p/HuR/HOXC6 axis

Cancer-associated fibroblasts (CAFs)-derived extracellular vesicles (EVs) can mediate tumorigenesis. Long noncoding RNA (LncRNA) SNHG3 is implicated in colorectal cancer (CRC) progression. The current study sought to clarify the role of CAFs-EVs carrying SNHG3 in CRC cell proliferation. Firstly, CAFs and normal fibroblasts (NFs) were cultured and identified, followed by isolation and characterization of CAFs-EVs and NFs-EVs. CRC cells were cultured with CAFs-EVs or CAFs-EVs overexpressing SNHG3. The effects of SNHG3 on CRC cell proliferation was evaluated using CCK-8, colony formation, and EdU staining assays. The binding relationships among SNHG3, miR-34b-5p, and HuR were validated, in addition to analyzing the binding between HuR and HOXC6. Lastly, xenograft tumor model was established to verify the role of CAFs-EVs carrying SNHG3 in vivo. SNHG3 was highly expressed in CRC cells and CAFs-EVs, whereas CAFs-EVs facilitated CRC cell proliferation. Mechanically, CAFs-EVs carried SNHG3 into CRC cells to upregulate HuR expression by competitively binding to miR-34b-5p, promote the binding of HuR and HOXC6, and enhance HOXC6 transcription. miR-34b-5p over-expression or HOXC6 silencing annulled the effect of CAFs-EVs. SNHG3 carried by CAFs-EVs facilitated CRC proliferation via the miR-34b-5p/HuR/HOXC6 axis in vivo. Collectively, our findings indicated that CAFs-EVs carried SNHG3 into CRC cells to upregulate HuR expression by sponging miR-34b-5p and finally enhance HOXC6 transcription, thereby facilitating CRC cell proliferation.

Regulatory function of DNA methylation mediated lncRNAs in gastric cancer

As one of the most common malignancies worldwide, gastric cancer contributes to cancer death with a high mortality rate partly responsible for its out-of-control progression as well as limited diagnosis. DNA methylation, one of the epigenetic events, plays an essential role in the carcinogenesis of many cancers, including gastric cancer. Long non-coding RNAs have emerged as the significant factors in the cancer progression functioned as the oncogene genes, the suppressor genes and regulators of signaling pathways over the decade. Intriguingly, increasing reports, recently, have claimed that abnormal DNA methylation regulates the expression of lncRNAs as tumor suppressor genes in gastric cancer and lncRNAs as regulators could exert the critical influence on tumor progression through acting on DNA methylation of other cancer-related genes. In this review, we summarized the DNA methylation-associated lncRNAs in gastric cancer which play a large impact on tumor progression, such as proliferation, invasion, metastasis and so on. Furthermore, the underlying molecular mechanism and signaling pathway might be developed as key points of gastric cancer range from diagnosis to prognosis and treatment in the future.

E2F4-induced AGAP2-AS1 up-regulation accelerates the progression of colorectal cancer via miR-182-5p/CFL1 axis

BACKGROUND

Long non-coding RNAs (lncRNAs) are closely associated with the pathogenesis of numerous diseases including cancers. LncRNA AGAP2 Antisense RNA 1 (AGAP2-AS1) has been found to participate in the tumorigenesis of several kinds of human cancers. Nonetheless, its potential function in colorectal cancer (CRC) was still poorly investigated.

METHODS

The expression level of RNAs or proteins was assessed by RT-qPCR or western blot analysis. Functional experiments were performed to analyze the role of AGAP2-AS1 in CRC in vitro and in vivo. Mechanism investigations were fulfilled to determine the potential mechanism of the molecules.

RESULTS

AGAP2-AS1 expression was significantly elevated in CRC cells and could be transcriptionally activated by E2F Transcription Factor 4 (E2F4). Down-regulated AGAP2-AS1 could weaken CRC cell growth, migration, invasion, and epithelial-mesenchymal transition (EMT). MicroRNA-182-5p (miR-182-5p) was the target downstream molecule of AGAP2-AS1. Furthermore, Cofilin 1 (CFL1) was proved as the target of miR-182-5p. Mechanically, AGAP2-AS1 could boost the CFL1 expression via competitively binding to miR-182-5p in CRC. Importantly, CFL1 restoration could counteract the in vitro and in vivo suppression of depleted AGAP2-AS1 on CRC progression.

CONCLUSION

E2F4-stimulated AGAP2-AS1 aggravated CRC development through regulating miR-182-5p/CFL1 axis, implying that AGAP2-AS1 might become a potent new target for future therapies for CRC.

Small nucleolar RNAs and SNHGs in the intestinal mucosal barrier: Emerging insights and current roles

BACKGROUND

Previous studies have focused on the involvement of small nucleolar RNAs (snoRNAs) and SNHGs in tumor cell proliferation, apoptosis, invasion, and metastasis via multiple pathways, including phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT), Wnt/β catenin, and mitogen-activated protein kinase (MAPK). These molecular mechanisms affect the integrity of the intestinal mucosal barrier.

AIM OF REVIEW

Current evidence regarding snoRNAs and SNHGs in the context of the mucosal barrier and modulation of homeostasis is fragmented. In this review, we collate the established information on snoRNAs and SNHGs as well as discuss the major pathways affecting the mucosal barrier.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Intestinal mucosal immunity, microflora, and the physical barrier are altered in non-neoplastic diseases such as inflammatory bowel diseases. Dysregulated snoRNAs and SNHGs may impact the intestinal mucosal barrier to promote the pathogenesis and progression of multiple diseases. SnoRNAs or SNHGs has been shown to be associated with poor disease behaviors, indicating that they may be exploited as prognostic biomarkers. Additionally, clarifying the complicated interactions between snoRNAs or SNHGs and the mucosal barrier may provide novel insights for the therapeutic treatment targeting strengthen the intestinal mucosal barrier.

SNHG3 Affects Gastric Cancer Development by Regulating SEPT9 Methylation

Background

Gastric cancer (GC) is a common malignancy that can be formed by methylation-induced deactivation of tumor silencer genes, which is one of the key mechanisms of tumorigenesis. SEPT9 methylation, a symptomatic marker for tumors, can downregulate gene expression. Long noncoding RNA small nucleolar host gene 3 (lncRNA SNHG3) is a new type of lncRNA related to cancer. Our study investigated the mechanism of SNHG3 regulation of SEPT9 methylation and its effects on the growth, metastasis, and spread of gastric cancer cells.

Methods

Quantitative real-time PCR (qRT–PCR) was used to detect SNHG3 and miR-448 in gastric cancer, and a dual-luciferase experiment verified the effects of SNHG3, miR-448, and DNMT1. After abnormally expressing SNHG3, miR-448, and DNMT1 alone or together, methylation-specific PCR was performed to determine the methylation of SEPT9, Western blotting was performed to detect the expression of DNA methyltransferase 1 (DNMT1) and SEPT9, and Transwell, scratch, and CCK-8 assays were performed to reveal the invasion, migration, and cell growth of gastric cancer cells.

Results

We found that SNHG3 was upregulated in gastric cancer and that SNHG3 knockdown or miR-448 overexpression inhibited SEP9 methylation and therefore increased its expression, thereby inhibiting the growth, metastasis, and spread of gastric cancer cells.

Conclusion

Our study indicates that SNHG3 regulates SEPT9 methylation by targeting miR-448/DNMT1 and subsequently affecting the occurrence and development of gastric cancer.

Small nucleolar RNA host gene 3 functions as a novel biomarker in liver cancer and other tumour progression

Cancer has become the most life-threatening disease in the world. Mutations in and aberrant expression of genes encoding proteins and mutations in noncoding RNAs, especially long noncoding RNAs (lncRNAs), have significant effects in human cancers. LncRNAs have no protein-coding ability but function extensively in numerous physiological and pathological processes. Small nucleolar RNA host gene 3 (SNHG3) is a novel lncRNA and has been reported to be differentially expressed in various tumors, such as liver cancer, gastric cancer, and glioma. However, the interaction mechanisms for the regulation between SNHG3 and tumor progression are poorly understood. In this review, we summarize the results of SNHG3 studies in humans, animal models, and cells to underline the expression and role of SNHG3 in cancer. SNHG3 expression is upregulated in most tumors and is detrimental to patient prognosis. SNHG3 expression in lung adenocarcinoma remains controversial. Concurrently, SNHG3 affects oncogenes and tumor suppressor genes through various mechanisms, including competing endogenous RNA effects. A deeper understanding of the contribution of SNHG3 in clinical applications and tumor development may provide a new target for cancer diagnosis and treatment.

Long Non-Coding RNAs in the Cell Fate Determination of Neoplastic Thymic Epithelial Cells

Thymic Epithelial Tumors (TETs) arise from epithelial cells of the thymus and are very rare neoplasms comprising Thymoma, Thymic carcinoma, and Thymic Neuroendocrine tumors that still require in-depth molecular characterization. Long non-coding RNAs (lncRNAs) are emerging as relevant gene expression modulators involved in the deregulation of several networks in almost all types of human cancer, including TETs. LncRNAs act at different control levels in the regulation of gene expression, from transcription to translation, and modulate several pathways relevant to cell fate determination under normal and pathological conditions. The activity of lncRNAs is strongly dependent on their expression, localization, and post-transcriptional modifications. Starting from our recently published studies, this review focuses on the involvement of lncRNAs in the acquisition of malignant traits by neoplastic thymic epithelial cells, and describes the possible use of these molecules as targets for the design of novel therapeutic approaches specific for TET. Furthermore, the involvement of lncRNAs in myasthenia gravis (MG)-related thymoma, which is still under investigation, is discussed.

Long Non-coding RNAs (lncRNAs), A New Target in Stroke

Stroke has become the most disabling and the second most fatal disease in the world. It has been a top priority to reveal the pathophysiology of stroke at cellular and molecular levels. A large number of long non-coding RNAs (lncRNAs) are identified to be abnormally expressed after stroke. Here, we summarize 35 lncRNAs associated with stroke, and clarify their functions on the prognosis through signal transduction and predictive values as biomarkers. Changes in the expression of these lncRNAs mediate a wide range of pathological processes in stroke, including apoptosis, inflammation, angiogenesis, and autophagy. Based on the exploration of the functions and mechanisms of lncRNAs in stroke, more timely, accurate predictions and more effective, safer treatments for stroke could be developed.

Bioinformatics Analysis Identified the Hub Genes, mRNA–miRNA–lncRNA Axis, and Signaling Pathways Involved in Rheumatoid Arthritis Pathogenesis

Objective

Rheumatoid arthritis (RA) is a nonspecific, chronic, systemic autoimmune disease characterized by symmetric polyarticular synovitis. Bioinformatics analysis of potential biomarkers, mRNA–miRNA–lncRNA axes, and signaling pathways in the pathogenesis of RA provides potential targets and theoretical basis for further research on RA.

Methods

The GSE1919 and GSE77298 datasets were downloaded from the Gene Expression Omnibus database (http://www.ncbi.nlm.nih.gov/geo). Perl was used to perform data merging, and R was used to perform batch correction. The “limma” package of R was used to screen differentially expressed genes, and the “clusterProfiler” package was used to perform enrichment analysis of the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. Search Tool for the Retrieval of Interacting Genes/Proteins was used to construct the protein–protein interaction network, Cytoscape was used for module analysis, and R was used to screen for hub genes. GraphPad Prism was used to plot the receiver operating characteristic curve of the hub genes. Gene set enrichment analysis and competitive endogenous RNA network analysis were performed on hub genes with the greatest diagnostic values. The hub gene with the greatest diagnostic value was verified using immunohistochemical staining.

Results

We obtained nine hub genes (ITGB2, VAMP8, HLA-A, PTAFR, SYK, FCER1G, HLA-DPB1, LCP2, and ACTR2) and four mRNA–miRNA–lncRNA axes (ITGB2-hsa-miR-486-3p-SNHG3, ITGB2-hsa-miR-338-5p-XIST, ITGB2-hsa-miR-5581-3p-XIST, and ITGB2-hsa-miR-1226-5p-XIST) related to the pathogenesis of RA. The nine hub genes were highly expressed, and ITGB2 had the highest diagnostic value for RA. We also identified signaling pathways related to the pathogenesis of RA: Fc epsilon Rl and chemokine signaling pathways. The immunohistochemical results showed that ITGB2 expression was significantly upregulated in RA.

Conclusion

The hub genes, mRNA–miRNA–lncRNA axes, and signaling pathways related to RA pathogenesis identified in this study provide a new research direction for the mechanism, diagnosis, and treatment of RA.

LncRNA SNHG3 Facilitates the Malignant Phenotype of Cholangiocarcinoma Cells via the miR-3173-5p/ERG Axis

BACKGROUND

Long noncoding RNA (lncRNA) small nucleolar RNA host gene 3 (SNHG3) is an oncogenic lncRNA that has been reported in many cancers, but the role of SNHG3 in cholangiocarcinoma (CCA) remains largely unknown. Bioinformatic analysis revealed a regulatory relationship among SNHG3, miR-3173-5p, and ERG. miR-3173-5p is a tumour suppressive miRNA, while ERG is an oncogene. In the present study, we focused on the regulatory effects and molecular mechanisms of SNHG3 in CCA.

METHOD

The expression of SNHG3 and miR-3173-5p was evaluated using qRT-PCR analysis. Knockdown of SNHG3 was achieved by shRNA. Cell viability was assessed by MTT assay. Migration and invasion were determined by Transwell assay. Flow cytometry was used to assess cell apoptosis. Western blots were applied to quantify protein levels. Furthermore, using RNA pulldown and dual luciferase assays, the interactions between SNHG3 and miR-3173-5p and between miR-3173-5p and ERG in CCA cells were validated.

RESULTS

SNHG3 was significantly upregulated in CCA cells compared with normal human intrahepatic biliary epithelial cells. Knockdown of SNHG3 inhibited the proliferation and migration of CCA cells. Mechanistically, SNHG3-sponged miR-3173-5p, thus releasing the repression of ERG by miR-3173-5p. Rescue experiments showed that the miR-3173-5p/ERG axis mediated the oncogenic effect of SNHG3.

CONCLUSION

Taken together, our data suggest that SNHG3 is a pleiotropic oncogenic lncRNA in CCA. Knockdown of SNHG3 expression suppressed malignant phenotypes in CCA cells via the miR-3173-5p/ERG axis.

SNHG3 could promote prostate cancer progression through reducing methionine dependence of PCa cells

In recent years, morbidity and mortality of prostate cancer (PCa) have increased dramatically, while mechanistic understanding of its onset and progression remains unmet. LncRNA SNHG3 has been proved to stimulate malignant progression of multiple cancers, whereas its functional mechanism in PCa needs to be deciphered. In this study, our analysis in the TCGA database revealed high SNHG3 expression in PCa tissue. Further analysis in starBase, TargetScan, and mirDIP databases identified the SNHG3/miR-152-3p/SLC7A11 regulatory axis. FISH was conducted to assess the distribution of SNHG3 in PCa tissue. Dual-luciferase reporter gene and RIP assays confirmed the relationship among the three objects. Next, qRT-PCR and western blot were conducted to measure expression levels of SNHG3, miR-152-3p, and SLC7A11. CCK-8, colony formation, Transwell, and flow cytometry were carried out to assess proliferation, migration, invasion, methionine dependence, apoptosis, and the cell cycle. It was noted that SNHG3 as a molecular sponge of miR-152-3p stimulated proliferation, migration, and invasion, restrained methionine dependence and apoptosis, and affected the cell cycle of PCa cells via targeting SLC7A11. Additionally, we constructed xenograft tumor models in nude mice and confirmed that knockdown of SNHG3 could restrain PCa tumor growth and elevate methionine dependence in vivo. In conclusion, our investigation improved understanding of the molecular mechanism of SNHG3 modulating PCa progression, thereby generating novel insights into clinical therapy for PCa.

Zebrafish xenograft model for studying the function of lncRNA SNHG4 in the proliferation and migration of colorectal cancer

BACKGROUND

The zebrafish xenograft model has become a reliable in vivo model for human cancer research. Compared to a mouse model, the zebrafish xenograft has many advantages, including optical transparency, intuitive in vivo observation, and speed. Long noncoding RNAs (lncRNAs) have been identified as crucial regulatory factors in the progression of colorectal cancer (CRC). The biological function of lncRNA small nucleolar RNA host gene 4 (SNHG4) in CRC is still unclear.

METHODS

We analyzed the expression of SNHG4 in CRC patient samples by the Gene Expression Profiling Interactive Analysis (GEPIA) software. The quantitative real time-polymerase chain reaction (qRT-PCR) was used to verify in CRC cell lines. The colony formation assay was used to study the cell proliferation, and we used the transwell assay to detect the migration ability. Then the zebrafish xenograft models were used to confirm these roles of SNHG4 in vivo. Moreover, we detected epithelial mesenchymal transition (EMT) related genes by qRT-PCR.

RESULTS

We found the expression of SNHG4 was upregulated in CRC patient samples by analyzing GEPIA software, which was also verified in CRC cell lines. We also found that silencing SNHG4 inhibited the proliferation and migration of CRC cells, and its roles were verified in zebrafish xenografts in vivo. Further, we found that the expression of E-cadherin was significantly upregulated and N-cadherin was downregulated when knocking-down SNHG4 in CRC cells.

CONCLUSIONS

Our findings demonstrated that SNHG4 played oncogenic roles in CRC, which could be a potential target for treatment of CRC patients, and the results strongly revealed that zebrafish xenograft could be used for functional research of lncRNAs in human cancer.

High expression of small nucleolar RNA host gene 3 predicts poor prognosis and promotes bone metastasis in prostate cancer by activating transforming growth factor-beta signaling

Bone metastasis is closely related to tumor death in prostate cancer (PC). Long noncoding RNA small nucleolar RNA host gene 3 (SNHG3) has been implicated in the initiation and progression of multiple human cancers. Nevertheless, the biological function of SNHG3 in PC has not been elucidated. Our results indicated that SNHG3 was upregulated in bone metastasis-positive PC tissues compared to bone metastasis-negative PC tissues and adjacent normal tissues. High expression of SNHG3 indicates advanced clinicopathological features and predicts poor prognosis in patients with PC. Meanwhile, SNHG3 knockdown suppressed the proliferation, migration, and invasion abilities of PC cells and inhibited PC cell metastasis to the bone. Mechanistically, SNHG3 enhanced the expression of transforming growth factor beta receptor 1 (TGFBR1) and activated transforming growth factor-Beta (TGF-β) signaling by targeting miR-214-3p. Our study demonstrated the novel role of the SNHG3/miR-214-3p/TGF-β axis in tumor growth and bone metastasis in PC, indicating that SNHG3 may act as a biomarker and promising therapeutic target against PC.

SnoRNA in Cancer Progression, Metastasis and Immunotherapy Response

Simple Summary

A much larger number of small nucleolar RNA (snoRNA) have been found encoded within our genomes than we ever expected to see. The activities of the snoRNAs were thought restricted to the nucleolus, where they were first discovered. Now, however, their significant number suggests that their functions are more diverse. Studies in cancers have shown snoRNA levels to associate with different stages of disease progression, including with metastasis. In addition, relationships between snoRNA levels and response to immunotherapies, have been reported. Emerging technologies now allow snoRNA to be targeted directly in cancers, and the therapeutic value of this is being explored.

Abstract

Small nucleolar RNA (snoRNA) were one of our earliest recognised classes of non-coding RNA, but were largely ignored by cancer investigators due to an assumption that their activities were confined to the nucleolus. However, as full genome sequences have become available, many new snoRNA genes have been identified, and multiple studies have shown their functions to be diverse. The consensus now is that many snoRNA are dysregulated in cancers, are differentially expressed between cancer types, stages and metastases, and they can actively modify disease progression. In addition, the regulation of the snoRNA class is dominated by the cancer-supporting mTOR signalling pathway, and they may have particular significance to immune cell function and anti-tumour immune responses. Given the recent advent of therapeutics that can target RNA molecules, snoRNA have robust potential as drug targets, either solely or in the context of immunotherapies.

The Role of Non-Coding RNAs in the Regulation of the Proto-Oncogene MYC in Different Types of Cancer

Alterations in the expression level of the MYC gene are often found in the cells of various malignant tumors. Overexpressed MYC has been shown to stimulate the main processes of oncogenesis: uncontrolled growth, unlimited cell divisions, avoidance of apoptosis and immune response, changes in cellular metabolism, genomic instability, metastasis, and angiogenesis. Thus, controlling the expression of MYC is considered as an approach for targeted cancer treatment. Since c-Myc is also a crucial regulator of many cellular processes in healthy cells, it is necessary to find ways for selective regulation of MYC expression in tumor cells. Many recent studies have demonstrated that non-coding RNAs play an important role in the regulation of the transcription and translation of this gene and some RNAs directly interact with the c-Myc protein, affecting its stability. In this review, we summarize current data on the regulation of MYC by various non-coding RNAs that can potentially be targeted in specific tumor types.

Predicting lncRNA-Protein Interaction With Weighted Graph-Regularized Matrix Factorization

Long non-coding RNAs (lncRNAs) are widely concerned because of their close associations with many key biological activities. Though precise functions of most lncRNAs are unknown, research works show that lncRNAs usually exert biological function by interacting with the corresponding proteins. The experimental validation of interactions between lncRNAs and proteins is costly and time-consuming. In this study, we developed a weighted graph-regularized matrix factorization (LPI-WGRMF) method to find unobserved lncRNA-protein interactions (LPIs) based on lncRNA similarity matrix, protein similarity matrix, and known LPIs. We compared our proposed LPI-WGRMF method with five classical LPI prediction methods, that is, LPBNI, LPI-IBNRA, LPIHN, RWR, and collaborative filtering (CF). The results demonstrate that the LPI-WGRMF method can produce high-accuracy performance, obtaining an AUC score of 0.9012 and AUPR of 0.7324. The case study showed that SFPQ, SNHG3, and PRPF31 may associate with Q9NUL5, Q9NUL5, and Q9UKV8 with the highest linking probabilities and need to further experimental validation.

Construction of Novel lncRNA-miRNA-mRNA Network Associated With Recurrence and Identification of Immune-Related Potential Regulatory Axis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant diseases globally. Despite continuous improvement of treatment methods, high postoperative recurrence rate remains an urgent problem. In order to determine the mechanism underlying recurrence of liver cancer and identify prognostic genes, data from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) were integrated and analyzed. Differentially expressed genes (DEGs) between HCC tissue and normal liver tissue were identified, and a protein-protein interaction network was constructed to find hub genes. Clinical correlation analysis and disease-free survival (DFS) analysis were performed using the R language and GEPIA to identify relapse-related genes. Correlation analysis was used to identify a potential regulatory axis. Dual-luciferase reporter gene assay was used to confirm the reliability of the long non-coding RNA (lncRNA)-microRNA (miRNA)-mRNA regulatory axis. Immune infiltration analysis was performed using the TIMER database. Correlations between immune gene markers and ASF1B were verified using quantitative real-time polymerase chain reaction (RT-qPCR). In this work, we found that nine lncRNAs and five mRNAs were significantly overexpressed in HCC tissues from patients with recurrence. SNHG3, LINC00205, ASF1B, AURKB, CCNB1, CDKN3, and DTL were also closely related to HCC grade and stage. Survival analysis showed that these seven DEGs were significantly correlated with poor DFS. Correlation analysis identified SNHG3-miR-214-3p-ASF1B as a potential regulatory axis. Dual-luciferase reporter gene assay showed that SNHG3 and ASF1B directly bound to miR-214-3p. ASF1B was negatively regulated by miRNA-214-3p, and overexpression of SNHG3 could inhibit the expression of miRNA-214-3p. In addition, ASF1B was positively correlated with immune infiltration. A reduction in ASF1B could markedly inhibit the expression of CD86, CD8, STAT1, STAT4, CD68, and PD1 in HCC cells. Flow cytometry showed that SNHG3 promoted the PD-1 expression by regulating ASF1B. Meanwhile, elevated ASF1B predicted poor prognosis of HCC patients in subgroups with decreased B cells, CD8+ T cells, or neutrophils, and those with enriched CD4+ T cells. In conclusion, we found that a novel lncRNA SNHG3/miR-214-3p/ASF1B axis could promote the recurrence of HCC by regulating immune infiltration.

LncRNA SNHG3 Promotes Gastric Cancer Cells Proliferation, Migration, and Invasion by Targeting miR-326

The function and possible mechanism of lncRNA Small Nucleolar RNA Host Gene 3 (SNHG3) in GC have not been fully studied. The aim of our study was to investigate the role of SNHG3 in the proliferation, migration, and invasion of GC cell lines. The expressions of SNHG3, miR-326, and TWIST in GC9811-P GC cell lines were detected by RT-qPCR. Western blotting was performed to detect the protein levels of TWIST and EMT-related genes. Luciferase reporter gene analysis and RNA immunoprecipitation (RIP) analysis confirmed the interaction between lncRNA SNHG3, miR-326, and TWIST. CCK-8 and Transwell assays were performed to detect cell proliferation, invasion, and migration abilities. The results showed that lncRNA SNHG3 and TWIST were highly expressed in GC cell lines, while miR-326 was expressed to a low degree. Moreover, lncRNA SNHG3 knockdown or miR-326 overexpression significantly inhibited cell proliferation, migration, and invasion of GC cell lines. In addition, TWIST overexpression can reverse the inhibition of lncRNA SNHG3 knockdown or miR-326 overexpression on cell proliferation, migration, and invasion. In conclusion, lncRNA SNHG3 may promote GC progression through the miR-326/TWIST axis, which may provide a new diagnostic and prognostic biomarker for GC.

Long noncoding RNA SNHG3 promotes glioma tumorigenesis by sponging miR-485-5p to upregulate LMX1B expression

LIM homeobox transcription factor 1-beta (LMX1B) has recently been found to be highly expressed in advanced gliomas and is associated with poor survival. However, the regulatory molecular mechanism of LMX1B expression in gliomas remains unclear. In this study, bioinformatics analysis showed that miR-485-5p may be the potential upstream regulator of LMX1B, and long noncoding RNA (lncRNA) small nucleolar RNA host gene 3 (SNHG3) may function as a competitive endogenous RNA to sponge miR-485-5p. In addition, the expression of SNHG3 and LMX1B in advanced glioma tissues was significantly upregulated, while the expression of miR-485-5p was significantly downregulated. SNHG3 overexpression reduced the expression of miR-485-5p; increased the expression of LMX1B; and promoted the proliferation, migration, and invasion of glioma cells. In contrast, miR-485-5p overexpression reduced the expression of LMX1B and inhibited cell proliferation, migration, and invasion. The luciferase reporter assay and RNA immunoprecipitation assay further confirmed the interaction between SNHG3 and miR-485-5p and between miR-485-5p and LMX1B. In addition, subcutaneous and orthotropic xenograft models confirmed that lncRNA SNHG3 silencing or miR-485-5p overexpression significantly reduced the growth of glioma xenografts and prolonged survival time. These results indicate that lncRNA SNHG3 can regulate the expression of LMX1B by sponging miR-485-5p, thereby promoting the proliferation, migration, and invasion of glioma cells. This study provides the first evidence that the SNHG3/miR-485-5p/LMX1B axis is involved in glioma tumorigenesis and highlights the potential of SNHG3 and miR-485-5p as therapeutic targets for glioma.

miRNA Clusters with Up-Regulated Expression in Colorectal Cancer

Simple Summary

As miRNAs show the capacity to be used as CRC biomarkers, we analysed experimentally validated data about frequently up-regulated miRNA clusters in CRC tissue. We identified 15 clusters that showed increased expression in CRC: miR-106a/363, miR-106b/93/25, miR-17/92a-1, miR-181a-1/181b-1, miR-181a-2/181b-2, miR-181c/181d, miR-183/96/182, miR-191/425, miR-200c/141, miR-203a/203b, miR-222/221, mir-23a/27a/24-2, mir-29b-1/29a, mir-301b/130b and mir-452/224. Cluster positions in the genome are intronic or intergenic. Most clusters are regulated by several transcription factors, and by long non-coding RNAs. In some cases, co-expression of miRNA with other cluster members or host gene has been proven. miRNA expression patterns in cancer tissue, blood and faeces were compared. The members of the selected clusters target 181 genes. Their functions and corresponding pathways were revealed with the use of Panther analysis. Clusters miR-17/92a-1, miR-106a/363, miR-106b/93/25 and miR-183/96/182 showed the strongest association with metastasis occurrence and poor patient survival, implicating them as the most promising targets of translational research.

Abstract

Colorectal cancer (CRC) is one of the most common malignancies in Europe and North America. Early diagnosis is a key feature of efficient CRC treatment. As miRNAs can be used as CRC biomarkers, the aim of the present study was to analyse experimentally validated data on frequently up-regulated miRNA clusters in CRC tissue and investigate their members with respect to clinicopathological characteristics of patients. Based on available data, 15 up-regulated clusters, miR-106a/363, miR-106b/93/25, miR-17/92a-1, miR-181a-1/181b-1, miR-181a-2/181b-2, miR-181c/181d, miR-183/96/182, miR-191/425, miR-200c/141, miR-203a/203b, miR-222/221, mir-23a/27a/24-2, mir-29b-1/29a, mir-301b/130b and mir-452/224, were selected. The positions of such clusters in the genome can be intronic or intergenic. Most clusters are regulated by several transcription factors, and miRNAs are also sponged by specific long non-coding RNAs. In some cases, co-expression of miRNA with other cluster members or host gene has been proven. miRNA expression patterns in cancer tissue, blood and faeces were compared. Based on experimental evidence, 181 target genes of selected clusters were identified. Panther analysis was used to reveal the functions of the target genes and their corresponding pathways. Clusters miR-17/92a-1, miR-106a/363, miR-106b/93/25 and miR-183/96/182 showed the strongest association with metastasis occurrence and poor patient survival, implicating them as the most promising targets of translational research.

Overexpression of lncRNA SNGH3 Predicts Unfavorable Prognosis and Clinical Outcomes in Human Cancers: Evidence from a Meta-Analysis

Long noncoding RNAs (lncRNAs) have been confirmed to play a crucial role in human disease, especially in tumor development and progression. Small nucleolar RNA host gene (SNHG3), a newly identified lncRNA, has been found dysregulated in various cancers. Nevertheless, the results remain controversial. Thus, we aim to analyze the comprehensive data to elaborate the association between SNHG3 expression and clinical outcomes in multiple cancers. We searched PubMed, Web of Science, Cochrane Library, Embase, and MEDLINE database to identify eligible articles. STATA software was applied to calculate the hazard ratio (HR) and odds ratio (OR) with 95% confidence interval (95% CI) for survival outcomes and clinical parameters, respectively. Besides, the data from The Cancer Genome Atlas (TCGA) dataset was extracted to verify the results in our meta-analysis. There were thirteen studies totaling 919 cancer patients involved in this meta-analysis. The results demonstrated that high SNHG3 expression was significantly associated with poor overall survival (OS) (HR = 2.53, 95% CI: 1.94-3.31) in cancers, disease-free survival (DFS) (HR = 3.89, 95% CI: 1.34-11.3), and recurrence-free survival (RFS) (HR = 2.42, 95% CI: 1.14-5.15) in hepatocellular carcinoma. Analysis stratified by analysis method, sample size, follow-up time, and cancer type further verified the prognostic value of SNHG3. Additionally, patients with high SNHG3 expression tended to have more advanced clinical stage, higher histological grade, earlier distant metastasis, and earlier lymph node metastasis. Excavation of TCGA dataset valuated that SNHG3 was upregulated in various cancers and predicted worse OS and DFS. Overexpressed SNHG3 was strongly associated with poor survival and clinical outcomes in human cancers and therefore can serve as a promising biomarker for predicting patients' prognosis.

A four-lncRNA signature for predicting prognosis of recurrence patients with gastric cancer

Purpose

This study aimed to develop a multi-long noncoding RNA (lncRNA) signature for the prediction of gastric cancer (GC) based on differential gene expression between recurrence and nonrecurrence patients.

Methods

By repurposing microarray expression profiles of RNAs from The Cancer Genome Atlas (TCGA), we performed differential expression analysis between recurrence and nonrecurrence patients. A prognostic risk prediction model was constructed based on data from TCGA database, and its reliability was validated using data from Gene Expression Omnibus database. Furthermore, the lncRNA-associated competing endogenous RNA (ceRNA) network was constructed, namely, DIANA-LncBasev2 and starBase database.

Results

We identified 363 differentially expressed RNAs (317 mRNAs, 18 lncRNAs, and 28 microRNAs [miRNAs]). Principal component analysis showed that the seven-feature lncRNAs screened by support vector machine-recursive feature elimination algorithm was more informative for predicting recurrence of GC in comparison with the eight-feature lncRNAs screened by random forest-out-of-bag algorithm. Four of the seven-feature lncRNAs including LINC00843, SNHG3, C21orf62-AS1, and MIR99AHG were chosen to develop a four-lncRNA risk score model. This risk score model was able to distinguish patients with high and low risk of recurrence, and was tested in two independent validation sets. The ceRNA network of this four-lncRNA signature included 10 miRNAs and 178 mRNAs. The mRNAs significantly related to the Wnt-signaling pathway and relevant biological processes.

Conclusion

A useful four-lncRNA signature recurrence was established to distinguish GC patients with high and low risk of recurrence. Regulating the relevant miRNAs and Wnt pathway might partly affect GC metastasisby.

Knockdown of Long Non-coding RNA SNGH3 by CRISPR-dCas9 Inhibits the Progression of Bladder Cancer

Recent research evidence documents that lncRNAs (long non-coding RNAs lncRNAs) play a pivotal role in the tumorigenesis and development of tumors. LncRNA SNGH3 (small nucleolar RNA host gene 3) is highly expressed in numerous forms of cancer, serving as an oncogene in cancer progression. Nonetheless, the clinical relationship, along with the mechanism of SNGH3 in bladder cancer, have not been studied. Herein, the findings exhibited upregulation of SNGH3 in bladder cancer tissues, along with the cell lines. Furthermore, overexpressed SNGH3 was positively linked to the TNM stage, as well as the histological grade of bladder cancer. Moreover, the silencing of SNGH3, using CRISPR-dCas9, suppressed cell growth along with migration, but elevated bladder cancer cell apoptosis. In summary, we established that SNGH3 serves as a bladder cancer oncogene and could be employed as a prospective diagnostic marker for clinical use, and is also a therapeutic target for CRISPR-mediated gene therapy.

SNHG3 promotes migration, invasion, and epithelial-mesenchymal transition of breast cancer cells through the miR-186-5p/ZEB1 axis

Increasing evidence suggests that the long non-coding RNAs (lncRNAs) participate in the development and progression of breast cancer. The lncRNA small nucleolar RNA host gene 3 (SNHG3) reportedly acts as an oncogene in hepatocellular carcinoma and colorectal cancer; however, little is known about the biological function and oncogenic mechanisms of SNHG3 in breast cancer. We demonstrated that the expression of SNHG3 was abnormally high in breast cancer tissues and cells, and transgenic expression of SNHG3 promoted the proliferation, migration, and invasion of breast cancer cell lines (MCF-7 and MDA-MB-231). The mean volume of the xenografts from the SNHG3-knockdown MCF-7 cells was lower than that of the control tumor cells. Moreover, the expression of zinc finger E-box binding homeobox 1 (ZEB1) increased after SNHG3 overexpression and vice versa. Overexpression of ZEB1 triggered cellular migration and invasion behaviors. Analysis of the mechanism underlying these effects suggested that SNHG3 is an effective sink for miR-186-5p and modulates ZEB1 repression, conferring an additional level to its post-transcriptional regulation. In conclusion, SNHG3 promotes the migration and invasion of breast cancer cells through miR-186-5p/ZEB1 regulation and the induction of the epithelial to mesenchymal transition, indicating that SNHG3 is a potential treatment target for breast cancer.

Long Noncoding RNA Small Nucleolar RNA Host Gene 3 Mediates Prostate Cancer Migration, Invasion, and Epithelial-Mesenchymal Transition by Sponging miR-487a-3p to Regulate TRIM25

Background: Long noncoding RNA small nucleolar RNA host gene 3 (SNHG3) is related to the proliferation and metastasis of cancer cells. This study aims to reveal the role of SNHG3 in prostate cancer (PCa), which may help prevent PCa metastasis. Methods: SNHG3 plasmid, SNHG3 siRNA, miR-487a-3p mimic, miR-487a-3p inhibitor, TRIM25 plasmid, and TRIM25 siRNA were transfected or cotransfected into LNCaP and PC-3 cells. The proliferation, migration, and invasion of PCa cells were measured by Cell Counting Kit-8, wound-healing, and transwell assays, respectively. The expressions of SNHG3, miR-487a-3p, E-cadherin, N-cadherin, Snail, and TRIM25 in PCa tissues and cells were measured by quantitative reverse transcription polymerase chain reaction or western blot. Results: SNHG3 expression level was upregulated in PCa tissues and cells. SNHG3 overexpression and miR-487a-3p inhibitor promoted cell viability, migration, invasion, and N-cadherin and Snail levels, and inhibited E-cadherin level in LNCaP cells, while SNHG3 silencing and miR-487a-3p mimic had the opposite effects on PC-3 cells. The inhibitory effect of miR-487a-3p mimic on the migration, invasion, and epithelial-mesenchymal transition (EMT) of LNCaP cells was inversed by both SNHG3 and TRIM25 plasmids. Similarly, the function of miR-487a-3p inhibitor in PC-3 cells was also inversed by SNHG3 siRNA and TRIM25 siRNA. Conclusion: SNHG3 mediates PCa migration, invasion, and EMT by sponging miR-487a-3p to regulate TRIM25. The Clinical Trial Registration number: Y20180831.

LncRNA SNHG3 Promotes Proliferation and Metastasis of Non-Small-Cell Lung Cancer Cells Through miR-515-5p/SUMO2 Axis

Lung cancer is a global disease and a major cause of cancer-related mortality worldwide. Accumulated studies have confirmed the essential role of long non-coding RNAs (lncRNAs) in the occurrence and development of cancers. Meanwhile, there have been reports concerning the role of Small Nucleolar RNA Host Gene 3 (SNHG3) in various cancers. However, there are so far few studies on the function and mechanism of SNHG3 in lung cancer. In the present study, SNHG3 was found to be highly expressed in lung cancer tissues and cells. Downregulation of SNHG3 could inhibit cell proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) process. In addition, SNHG3 was found to have the ability to bind to miR-515-5p. Furthermore, Small Ubiquitin Like Modifier 2 (SUMO2) was identified to be the downstream target of miR-515-5p, which was negatively correlated with miR-515-5p expression. SNHG3 could positively regulate SUMO2 expression by sponging miR-515-5p. In addition, the rescue experiment showed that simultaneous transfection of miR-515-5p or SUMO2 siRNA could reverse the effect of SNHG3 expression on cell proliferation and metastasis. Collectively, our study demonstrates that SNHG3 can act on miR-515-5p in the form of competitive endogenous RNA (ceRNA) to regulate SUMO2 positively and thus affect the proliferation and metastasis of NSCLC cells. Findings in our study support that SNHG3/miR-515-5p/SUMO2 regulatory axis may become a potential therapeutic target for lung cancer.

SOX9-activated FARSA-AS1 predetermines cell growth, stemness, and metastasis in colorectal cancer through upregulating FARSA and SOX9

SRY-box transcription factors (SOXs) are effective inducers for the formation of stem-like phenotypes. As a member of SOX family, SOX9 (SRY-box transcription factor 9) has been reported to be highly expressed and exert oncogenic functions in multiple human cancers. In this study, we hypothesized that SOX9 could regulate the function of cancer stem/initiating cells (CSCs) to further facilitate the progression of colorectal cancer (CRC). Then, stable transfection of shRNAs was used to silence indicated genes. Loss-of-function experiments were conducted to demonstrate the in vitro function of CRC cells. In vivo study was conducted to determine the changes in tumorigenesis and metastasis in vivo. Bioinformatics analyses and mechanistic experiments were employed to explore the downstream molecules. Presently, GEPIA data indicated that SOX9 was upregulated in 275 COAD (colon adenocarcinoma) samples relative to 349 normal tissues. Besides, we also proved the upregulation of SOX9 in CRC cell lines (HCT15, SW480, SW1116, and HT-29) compared to normal NCM-460 cells. Silencing of SOX9 suppressed cell growth, stemness, migration, and invasion. Mechanistically, SOX9 activated the transcription of lncRNA phenylalanyl-tRNA synthetase subunit alpha antisense RNA 1 (FARSA-AS1), while FARSA-AS1 elevated SOX9 in turn by absorbing miR-18b-5p and augmented FARSA via sequestering miR-28-5p. Furthermore, loss of FARSA-AS1 hindered malignant phenotypes in vitro and blocked tumor growth and metastasis in vivo. Notably, we testified that FARSA-AS1 aggravated the malignancy in CRC by enhancing SOX9 and FARSA. Our study unveiled a mechanism of SOX9-FARSA-AS1-SOX9/FARSA loop in CRC, which provides some clews of promising targets for CRC.

LncRNA SNHG3, a potential oncogene in human cancers

Long noncoding RNAs (lncRNAs) are composed of > 200 nucleotides; they lack the ability to encode proteins but play important roles in a variety of human tumors. A large number of studies have shown that dysregulated expression of lncRNAs is related to tumor oncogenesis and progression. Emerging evidence shows that SNHG3 is a novel oncogenic lncRNA that is abnormally expressed in various tumors, including osteosarcoma, liver cancer, lung cancer, etc. SNHG3 primarily competes as a competitive endogenous RNA (ceRNA) that targets tumor suppressor microRNAs (miRNAs) and ceRNA mechanisms that regulate biological processes of tumors. In addition, abnormal expression of SNHG3 is significantly correlated with patient clinical features. Upregulation of SNHG3 contributes to biological functions, including tumor cell proliferation, migration, invasion and EMT. Therefore, SNHG3 may represent a potential diagnostic and prognostic biomarker, as well as a novel therapeutic target.

Long-Chain Non-Coding RNA SNHG3 Promotes the Growth of Ovarian Cancer Cells by Targeting miR-339-5p/TRPC3 Axis

Background

Long-chain non-coding RNA (lncRNA) small nucleolar RNA host gene 3 (SNHG3) is reportedly overexpressed in malignant tumors, but its regulatory role in human ovarian cancer (OC) is not fully understood.

Methods

A qRT-PCR assay was carried out to detect the level of SNHG3 in OC tissues, serum and cells, a CCK-8 assay to measure the proliferation of OC cells, a transwell assay to measure the invasion and migration of OC cells, and a flow cytometry to detect the cell cycle distribution and apoptosis rate of OC cells. In addition, in vivo experiment was also conducted to determine the effect of SNHG3 on the growth of OC cells.

Results

SNHG3 was overexpressed in OC tissues, serum, and cells, and the overexpression in serum indicated a poor prognosis of patients. It was also found that knockdown of SNHG3 could inhibit the malignant phenotypes of OC cells, cause G1/G0 cell cycle arrest, and intensify apoptosis. Furthermore, in in vitro experiments, the growth ability of OC cells was inhibited under knockdown of SNHG3. Assays for relationship verification showed that SNHG3 regulated the expression of miR-339-5p and the canonical transient receptor potential 3 (TRPC3), and the rescue experiment revealed that co-transfection of si-SNHG3+miR-339-5p-inhibitor or si-SNHG3+pcDNA3.1-TRPC3 could reverse the effects of knockdown of SNHG3 on the biological behavior of OC cells.

Conclusion

SNHG3 can be adopted as a marker for diagnosis and prognosis evaluation of OC and it plays a role in the progression of OC by enabling the miR-339-5p sponge to regulate TRPC3 expression.

Five lncRNAs Associated With Prostate Cancer Prognosis Identified by Coexpression Network Analysis

Prostate cancer (PCa) is a highly malignant tumor, with increasing incidence and mortality rates worldwide. The aim of this study was to identify the prognostic lncRNAs and construct an lncRNA signature for PCa diagnosis by the interaction network between lncRNAs and protein-coding genes (PCGs). The differentially expressed lncRNAs (DElncRNAs) and PCGs (DEPCGs) between PCa and normal prostate tissues were screened from The Cancer Genome Atlas (TCGA) database. The DEPCGs were functionally annotated in terms of the enriched pathways. Weighted gene co-expression network analysis (WGCNA) of 104 PCa samples identified 15 co-expression modules, of which the Turquoise module was negatively correlated with cancer and included 5 key lncRNAs and 47 PCGs. KEGG pathway analyses of the core 47 PCGs showed significant enrichment in classic PCa-related pathways, and overlapped with the enriched pathways of the DEPCGs. LINC00857, LINC00900, LINC00908, LINC00900, SNHG3 and FENDRR were significantly associated with the survival of PCa and have not been reported previously. Finally, Multivariable Cox regression analysis was used to establish a prognostic risk formula, and the patients were accordingly stratified into the low- and high-risk groups. The latter had significantly worse OS compared to the low-risk group (P < 0.01), and the area under the receiver operating characteristic curve (ROC) of 14-year OS was 0.829. The accuracy of our prediction model was determined by calculating the corresponding concordance index (C-index) and risk curves. In conclusion, we established a 5-lncRNA prognostic signature that provides insights into the biological and clinical relevance of lncRNAs in PCa.

Network-Based Coexpression Analysis Identifies Functional and Prognostic Long Noncoding RNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a primary liver cancer associated with a growing incidence and extremely high mortality. However, the pathogenic mechanism is still not fully understood. In the present study, we identified 1,631 upregulated and 1,515 downregulated genes and found that cell cycle and metabolism-related pathways or biological processes highly dysregulated in HCC. To assess the biological importance of these DEGs, we carried out weighted gene coexpression network analysis (WGCNA) to identify the functional modules potentially involved in HCC pathogenesis or progression. The five modules were detected with Dynamic Tree Cut algorithm, and GO enrichment analysis revealed that these modules exhibited different biological processes or signaling pathways, such as metabolism-related pathways, cell proliferation-related pathways, and molecules in tumor microenvironment. Moreover, we also observed two immune cells, namely, cytotoxic cells and macrophage enriched in modules grey and brown, respectively, while T helper cell-2 (Th2) was enriched in module turquoise. Among the WGCNA network, four hub long noncoding RNAs (lncRNAs) were identified to be associated with HCC prognostic outcomes, suggesting that coexpression network analysis could uncover lncRNAs with functional importance, which may be associated with prognostic outcomes of HCC patients. In summary, this study demonstrated that network-based analysis could identify some functional modules and some hub-lncRNAs, which may be critical for HCC pathogenesis or progression.

Long non-coding RNA SNHG3, induced by IL-6/STAT3 transactivation, promotes stem cell-like properties of gastric cancer cells by regulating the miR-3619-5p/ARL2 axis

BACKGROUND

Chemotherapy is, next to surgery and radiotherapy, the mainstay regimen for the clinical management of gastric cancer. This therapy is, however, heavily compromised by the acquisition of resistance. Here, we aimed to clarify the potential involvement of long non-coding RNA SNGH3 in the acquisition of cisplatin resistance and stemness in gastric cancer.

METHODS

Cell viability and proliferation were measured using Cell Counting Kit-8 and colony formation assays, respectively. Stem cell-like cell growth was evaluated using a mammosphere formation assay. RNA levels of SNHG2, OCT-4, SOX-2, CD44, miR-3619-5p and ARL2 were determined using qRT-PCR, whereas protein levels of OCT-4, SOX-2, CD44, ARL2, STAT3 and pSTAT3 were determined using Western blotting. Dual luciferase reporter assays were employed to interrogate regulatory interactions between STAT3, SNHG3, miR-3619-5p and ARL2, respectively. Direct binding of STAT3 to the SNHG3 promoter was investigated using a chromatin immunoprecipitation assay.

RESULTS

We found that IL-6 triggered stem cell-like properties in cisplatin-treated gastric cancer cells and activated STAT3, which in turn transcriptionally regulated SNHG3 expression. SNHG3 expression up-regulation positively correlated with cisplatin resistance and stemness of gastric cancer cells, while SNHG3 down-regulation inhibited stem cell-like properties. In addition, we found that SNHG3 up-regulated ARL2 expression through sponging miR-3619-5p, which predominantly mediated the oncogenic properties of SNHG3 in this disease.

CONCLUSIONS

Our data indicate an involvement of aberrant SNHG3 over-expression in the acquisition of both cisplatin resistance and stemness of gastric cancer cells, and of the IL-6/STAT3/SNHG3/miR-3619-5p/ARL2 signaling cascade in the oncogenic properties of SNHG3.

Long non-coding RNA SNHG3 accelerates progression in glioma by modulating miR-384/HDGF axis

Glioma is a malignant primary brain tumor that occurs in the central nervous system and has threatened the well-being of millions of patients. It is well acknowledged that long non-coding RNA (lncRNA) SNHG3 participates in the regulation of proliferation, inflation, differentiation, and metastasis in many cancers. However, the regulatory effect of SNHG3 on glioma progression is still controversial. The expression of SNHG3 and HDGF was upregulated, whereas miR-384 was downregulated in glioma tissues, compared with the normal tissues. Interestingly, high SNHG3 contributed to low survival rate while low SNHG3 showed the opposite result. Moreover, SNHG3 or HDGF knockdown significantly suppressed proliferation, migration, and invasion and induced apoptosis in glioma. Meanwhile, restoration of HDGF abrogated the inhibition of SNHG3 silencing on glioma cell progression. Besides, miR-384 inhibitor attenuated SNHG3 silencing induced inhibition on HDGF mRNA and protein expression in A172 and SHG44 cells. LncRNA SNHG3 promotes cell proliferation, migration, and invasion in glioma by enhancing HDGF expression via miR-384 sponging, representing the promising targets for the development of novel therapeutic strategies.

Long non-coding RNA SNHG3 promotes breast cancer cell proliferation and metastasis by binding to microRNA-154-3p and activating the notch signaling pathway

BACKGROUND

Breast cancer (BC) is a malignant tumor that occurs in the epithelial tissue of the breast gland. Long non-coding RNA (lncRNA) small nucleolar RNA host gene 3 (SNHG3) has been found to promote BC cell proliferation and invasion by regulating the microRNA (miR)-101/zinc-finger enhancer binding axis in BC. Herein, the objective of the present study is to evaluate the effect of lncRNA SNHG3 on BC cell proliferation and metastasis with the Notch signaling pathway.

METHODS

Differentially expressed lncRNA in BC tissues and normal breast tissues was analyzed. SNHG3 si-RNA-1 and SNHG3 si-RNA-2 were constructed to detect the mechanism of SNHG3 interference in BC cell proliferation, viability, migration and invasion. Then, dual-luciferase reporter gene assay was utilized to verify the binding relation between SNHG3 and miR-154-3p as well as miR-154-3p and Notch2. Moreover, xenograft transplantation was applied to confirm the in vitro experiments.

RESULTS

Highly expressed SNHG3 was observed in BC tissues. The growth of BC cells in vivo and in vitro was evidently repressed after silencing SNHG3. BC cell invasion and migration were inhibited by silencing SNHG3 in vitro. SNHG3 could act as a competing endogenous RNA of miR-154-3p and upregulate the Notch signaling pathway to promote BC cell development. Activation of the Notch signaling pathway can partly reverse the inhibition of cell activity induced by silencing SNHG3.

CONCLUSION

Our study demonstrated that interfered lncRNA SNHG3 promoted BC cell proliferation and metastasis by activating the Notch signaling pathway. This investigation may offer new insight for BC treatment.

lncRNA SNHG3 promotes breast cancer progression by acting as a miR‑326 sponge

Accumulating evidence suggests that long noncoding RNA (lncRNA) small nucleolar RNA host gene 3 (SHNG3) plays crucial roles in the initiation and progression of various types of malignant cancers. Yet, the role played by SNHG3 in breast cancer as well as the associated mechanisms remain largely unclear. The expression of SNHG3 was detected in breast cancer tissues and cell lines by reverse-transcription quantitative PCR (RT-qPCR). Cell proliferation, colony formation, cell cycle distribution, migration and invasion abilities were detected by Cell Counting Kit-8, colony formation assay, flow cytometry, wound-healing and Matrigel invasion assays, respectively. The regulatory relationships between SNHG3 and miR-326 were explored by luciferase reporter assay. A nude mouse model was established to investigate the effect of SNHG3 in vivo. The results showed an upregulation of SNHG3 in breast cancer tissues and cell lines. Loss-of-function assays revealed significant suppression of breast cancer behaviors such as: Abilities to proliferate, form colonies, migrate and invade in vitro coupled with a delayed growth of tumors in vivo when SNHG3 was knocked down. Mechanically, it was shown that SNHG3 served as a competing endogenous RNA (ceRNA) of miR-326 that in turn is a tumor suppressor in this cancer. The correlation between the expression of SNHG3 and miR-326 was found to be strongly negative in these samples. Additionally, we found that inhibition of SNHG3 caused a partially reversal in the inhibition exerted by miR-326 on the ability of these cells to proliferate, form colonies, migrate and invade. Collectively, these findings suggest the functioning of SNHG3 as a ceRNA to enhance the ability of breast cancer cells to proliferate and metastasize to putatively serve as a new target to explore therapeutic intervention of this malignancy.

SNHG3 Functions as miRNA Sponge to Promote Breast Cancer Cells Growth Through the Metabolic Reprogramming

Cancer-associated fibroblasts (CAFs) are important ingredient in tumor microenvironment. The dynamic interplay between CAFs and cancer cells plays essential roles during tumor development and progression. However, the mechanisms of intercellular communication between CAFs and cancer cells remain largely unknown. We characterized exosomes secreted from breast cancer patient-derived CAFs by transmission electron microscopy. The expression of SNHG3, miR-330-5p, and PKM (Pyruvate Kinase M1/M2) was examined by real-time QPCR and immunoblot. The function of SNHG3 on the growth and metabolism of tumor cells was used by CCK8 and mitochondrial oxygen consumption assays. The binding between SNHG3, miR-330-5p, and PKM was examined by dual luciferase reporter assays. Orthotopical xenograft of breast tumor experiments was performed to determine the function of SNHG3 in vivo. We demonstrated that exosomes secreted from CAFs reprogram the metabolic pathways after tumor cells uptake the exosomes. CAF-secreted exosomal lncRNA SNHG3 served as a molecular sponge for miR-330-5p in breast cancer cells. Moreover, PKM could be targeted by miR-330-5p and was controlled by SNHG3 in breast cancer cells. Mechanistically, SNHG3 knockdown in CAF-secreted exosomes suppressed glycolysis metabolism and cell proliferation by the increase of miR-330-5p and decrease of PKM expression in tumor cells. SNHG3 functions as a miR-330-5p sponge to positively regulate PKM expression, inhibit mitochondrial oxidative phosphorylation, increase glycolysis carboxylation, and enhance breast tumor cell proliferation. Overall, SNHG3 could play a major role in the development and progression of breast cancer and support the therapeutic potential of targeting communication between cancer cells and tumor microenvironment.

LncRNA SNHG3 promotes bladder cancer proliferation and metastasis through miR-515-5p/GINS2 axis

Growing evidence suggests that long non‐coding RNAs (lncRNAs) are associated with carcinogenesis. LncRNA small nucleolar RNA host gene 3 (SNHG3) is up‐regulated in various cancers and positively associated with poor prognosis of these cancers. However, the precise role of lncRNA SNHG3 in bladder cancer (Bca) remains unclear. In our research, we first reported that lncRNA SNHG3 was up‐regulated in bladder cancer tissues and positively related to poor clinical prognosis. Moreover, knockdown of lncRNA SNHG3 significantly suppressed the proliferation, migration, invasion and EMT process of Bca cells in vitro and vivo. Mechanistically, we revealed that suppression of SNHG3 evidently enhanced miR‐515‐5p expression and decreased GINS2 expression at posttranscriptional levels. Moreover, SNHG3 positively regulated GINS2 expression by sponging miR‐515‐5p under a competing endogenous RNA (ceRNA) mechanism. To sum up, our study suggested lncRNA SNHG3 acted as a microRNA sponge and an oncogenic role in the progression of bladder cancer.