Long non-coding RNA SNHG4 promotes cervical cancer progression through regulating c-Met via targeting miR-148a-3p

The siRNA-mediated knockdown of SNHG4 efficiently induced pro-apoptotic signaling and suppressed metastasis in SW1116 colorectal cancer cell line

BACKGROUND

Long non-coding RNAs are broadly dysregulated in disease conditions, especially cancer, and are associated with tumor initiation, invasion, and overall survival. This study aimed to elucidate the expression level of Small Nucleolar RNA Host Gene 4 (SNHG4) lncRNA in colorectal cancer (CRC) and its effect on cell cycle progression, invasion, and death.

METHODS AND RESULTS

We evaluated the expression level of SNHG4 in clinical samples, including CRC tissues, adenomatous colorectal polyps (ACP), and their marginals. SNHG4-silenced SW1116 cells were used to evaluate the cell viability, cycle arrest, invasion, and apoptosis using MTT assay, scratching, flow cytometry, and immunoblotting. We also predicted molecular networks related to the SNHG4 involvement in CRC development. Results showed that SNHG4 expresses in cancerous tissues significantly higher than in polyps and marginals. This overexpression discriminated CRC from marginals and ACP with a suitable prognostic potential. Silencing of SNHG4 arrested the cell cycle at S and G2 phases and promoted early apoptosis in SW1116. It affected the active form of MMP2 and prevented cell invasion. Sponging of miRNAs which promotes the choline metabolism is the probable mechanism of SNHG4 involvement in CRC.

CONCLUSIONS

In conclusion, SNHG4 promotes CRC by dysregulating apoptosis and cell migration, and shows significant prognostic potential for CRC.

Long Non-Coding RNA Small Nucleolar RNA Host Gene 4 Induced by Transcription Factor SP1 Promoted the Progression of Nasopharyngeal Carcinoma Through Modulating microRNA-510-5p/Centromere Protein F Axis

Long non-coding RNAs (LncRNAs) are implicated with tumorigenesis and the development of nasopharyngeal carcinoma (NPC). Previous studies suggested that long non-coding RNA small nucleolar RNA host gene 4 (SNHG4) exerted oncogenic roles in various cancers. However, the function and molecular mechanism of SNHG4 in NPC have not been investigated. In our study, it was confirmed that the SNHG4 level was enriched in NPC tissues and cells. Functional assays indicated that SNHG4 depletion inhibited the proliferation and metastasis but promoted apoptosis of NPC cells. Furthermore, we identified miR-510-5p as a downstream gene of SNHG4 in NPC cells and SNHG4 upregulated CENPF expression by binding to miR-510-5p. Moreover, there was a positive (or negative) association between CENPF and SNHG4 (or miR-510-5p) expression in NPC. In addition, rescue experiments verified that CENPF overexpression or miR-510-5p silencing abrogated inhibitory effects on NPC tumorigenesis caused by SNHG4 deficiency. The study demonstrated that SNHG4 promoted NPC progression via miR-510-5p/CENPF axis, providing a novel potential therapeutic target for NPC treatments.

LncRNA SNHG4 promotes prostate cancer cell survival and resistance to enzalutamide through a let-7a/RREB1 positive feedback loop and a ceRNA network

BACKGROUND

Prostate cancer threatens the health of men over sixty years old, and its incidence ranks first among all urinary tumors among men. Enzalutamide remains the first-line drug for castration-resistant prostate cancer, however, tumors inevitably become resistant to enzalutamide. Hence, it is of great importance to investigate the mechanisms that induce enzalutamide resistance in prostate cancer cells.

METHODS

Bioinformatic analyzing approaches were used to identified the over-expressed genes in prostate cancer tumor tissues from three GEO datasets. qRT-PCR, western blotting and immunochemistry/In situ hybridization staining assays were performed to assess the expression of SNHG4, RRM2, TK1, AURKA, EZH2 and RREB1. Cell cycle was measured by flow cytometry. CCK-8, plate colony formation and EdU assays were performed to assess the cell proliferation. Senescence-associated β-Gal assay was used to detect the cell senescence level. γ-H2AX staining assay was performed to assess the DNA damages of PCa cells. Luciferase reporter assay and RNA immunoprecipitation assay were performed to verify the RNA-RNA interactions. Chromatin immunoprecipitation assay was performed to assess the bindings between protein and genomic DNA.

RESULTS

We found that RRM2 and NUSAP1 are highly expressed in PCa tumors and significantly correlated with poor clinical outcomes in PCa patients. Bioinformatic analysis as well as experimental validation suggested that SNHG4 regulates RRM2 expression via a let-7 miRNA-mediated ceRNA network. In addition, SNHG4 or RRM2 knockdown significantly induced cell cycle arrest and cell senescence, and inhibited DNA damage repair and cell proliferation, and the effects can be partially reversed by let-7a knockdown or RRM2 reoverexpression. In vitro and in vivo experiments showed that SNHG4 overexpression markedly enhanced cell resistance to enzalutamide. RREB1 was demonstrated to transcriptionally regulate SNHG4, and RREB1 was also validated to be a target of let-7a and thereby regulated by the SNHG4/let-7a feedback loop.

CONCLUSION

Our study uncovered a novel molecular mechanism of lncRNA SNHG4 in driving prostate cancer progression and enzalutamide resistance, revealing the critical roles and therapeutic potential of RREB1, SNHG4, RRM2 and let-7 miRNAs in anticancer therapy.

A1BG-AS1 promotes the biological functions of osteosarcoma cells via regulating the microRNA-148a-3p/USP22 axis and stabilizing the expression of SIRT1 through deubiquitinase function

BACKGROUND

The study aims to explore the role of A1BG antisense RNA 1 (A1BG-AS1), microRNA (miR)-148a-3p and ubiquitin-specific protease 22 (USP22) on osteosarcoma (OS) cell growth.

RESEARCH DESIGN & METHODS

A1BG-AS1, miR-148a-3p, USP22, and silent information regulator 2 homolog 1 (SIRT1) levels in OS tissues and cells were determined. The effects of A1BG-AS1, miR-148a-3p, and USP22 on the biological functions of OS cells were examined by functional assays. In vivo assay was conducted to observe the effect of A1BG-AS1 on OS growth in vitro. The relationship of A1BG-AS1, miR-148a-3p, and USP22 was analyzed by bioinformatics analysis, RNA-fluorescence in situ hybridization, luciferase activity, and RNA binding protein immunoprecipitation assays. The relation between USP22 and SIRT1 was evaluated by immunoprecipitation.

RESULTS

A1BG-AS1 and USP22 were highly expressed, and miR-148a-3p was lowly expressed in OS tissues and cells. Down-regulation of A1BG-AS1 and USP22 or up-regulation of miR-148a-3p impaired the malignant behaviors of OS cells. A1BG-AS1 sponged miR-148a-3p, and miR-148a-3p targeted USP22, thereby inhibiting USP22 expression. Up-regulating USP22 reversed the A1BG-AS1 suppression-induced phenotypic inhibition of OS cells. USP22 affected the biological functions of OS cells by deubiquitinating SIRT1.

CONCLUSION

A1BG-AS1 facilitates the biological functions of OS cells via mediating the miR-148a-3p/USP22 axis.

The mechanisms and diagnostic potential of lncRNAs, miRNAs, and their related signaling pathways in cervical cancer

Cervical cancer (CC), the fourth most prevalent type of cancer among women worldwide, is associated with high rates of morbidity and mortality. Due to the long period of latency in CC, most patients are already in the middle to late stages when initially diagnosed, which greatly reduces the clinical cure rate and quality of survival, thus resulting in poor outcomes. In recent years, with continuous exploration in the fields of bioinformatics and molecules, it has been found that ncRNAs, including miRNAs and lncRNAs, without the ability to translate proteins are capable of activating or inhibiting certain signaling pathways by targeting and modulating the level of expression of proteins involved in these signaling pathways. ncRNAs play important roles in assisting with diagnosis, drug administration, and prediction of prognosis during CC progression. As an entry point, the mechanisms of interaction between miRNAs, lncRNAs, and signaling pathways have long been a focus in basic research relating to CC, and numerous experimental studies have confirmed the close relationship of miRNAs, lncRNAs, and signaling pathways with CC development. Against this background, we summarize the latest advances in the involvement of lncRNA- and miRNA-related signaling pathways in the development of CC to provide guidance for CC treatment.

Long non-coding RNAs as critical regulators and novel targets in cervical cancer: current status and future perspectives

Cervical cancer is among the leading causes of cancer-associated mortality in women. In spite of vaccine availability, improved screening procedures, and chemoradiation therapy, cervical cancer remains the most commonly diagnosed cancer in 23 countries and the leading cause of cancer deaths in 36 countries. There is, therefore, a need to come up with novel diagnostic and therapeutic targets. Long non-coding RNAs (lncRNAs) play a remarkable role in genome regulation and contribute significantly to several developmental and disease pathways. The deregulation of lncRNAs is often observed in cancer patients, where they are shown to affect multiple cellular processes, including cell cycle, apoptosis, angiogenesis, and invasion. Many lncRNAs are found to be involved in the pathogenesis as well as progression of cervical cancer and have shown potency to track metastatic events. This review provides an overview of lncRNA mediated regulation of cervical carcinogenesis and highlights their potential as diagnostic and prognostic biomarkers as well as therapeutic targets for cervical cancer. In addition, it also discusses the challenges associated with the clinical implication of lncRNAs in cervical cancer.

Small nucleolar RNA host gene 25 is a long non-coding RNA helps diagnose and predict outcomes in prostate cancer

BACKGROUND

The role of a long non-coding RNA called small nucleolar RNA host gene 25 (SNHG25) has been studied in some tumor types but the correlation between SNHG25 and PCA remains unknown.

METHODS

The relationship between clinicopathologic characteristics and SNHG25 expression was evaluated using The Cancer Genome Atlas data. The binary classifier value of SNHG25 was calculated using areas under receiver operating characteristic (ROC) curves. Outcomes were evaluated using Kaplan-Meier and Cox regression analyses. Gene set enrichment was performed to identify potential SNHG25 functions.

RESULTS

SNHG25 expression was significantly increased in PCA and correlated with age, primary therapy outcome, N stage, Gleason score, and residual tumor (p < 0.05). ROC curves demonstrated the effect of SNHG25 on diagnosis and outcomes (area under the curve = 0.923). Higher SNHG25 expression predicted shorter progression-free interval (PFI) (p < 0.001), and Cox regression showed that SNHG25 expression was an independent risk factor for reduced PFI (p = 0.028). SNHG25 expression was associated with mRNA and protein metabolism.

CONCLUSIONS

SNHG25 expression increases significantly in PCA and is negatively associated with PFI. It is a potential diagnostic and prognostic biomarker in PCA.

Long Non-Coding RNA SNHG4 Expression in Women with Endometriosis: A Pilot Study

BACKGROUND

Endometriosis is a chronic disease of the genital organs that mainly affects women of reproductive age. The analysis of long non-coding RNA (lncRNA) in endometriosis is a novel field of science. Recently, attention has been drawn to SNHG4, which is incorrectly expressed in various human diseases, including endometriosis.

AIM

The aim of this pilot study was to analyze the expression of lncRNA small nucleolar RNA host gene 4 (SNHG4) and to investigate its significance in endometriosis.

MATERIAL AND METHODS

LncRNA SNHG4 expression was investigated in paraffin blocks in endometriosis patients (n = 100) and in endometriosis-free controls (n = 100) using a real-time PCR assay.

RESULTS

This study revealed a higher expression of SNHG4 in endometriosis patients than in controls. A statistically significant relationship between expression level and SNHG4 was found in relation to The Revised American Society for Reproductive Medicine classification of endometriosis, 1996, in the group of patients with endometriosis.

CONCLUSION

This pilot study has revealed that gene expression in SNHG4 plays an important role in the pathogenesis of endometriosis.

The Regulatory Mechanisms and Clinical Significance of Lnc SNHG4 in Cancer

BACKGROUND

LncRNAs have been reported to be involved in a variety of biological functions, including gene expression, cell growth, and differentiation. They may also serve as oncogenes or tumor suppressor genes in diseases. lncRNAs that can encode small nucleolar RNAs (snoRNAs) have been named small nucleolar RNA host genes (SNHGs).

OBJECTIVE

In this review article, we readily review the regulatory mechanisms and clinical significance of Lnc SNHG4 in cancer.

METHODS

We systematically investigated databases, like Scopus, PubMed, Embase, Google Scholar, and Cochrane Library database for all research articles, and have provided an overview regarding the biological functions and mechanisms of lncRNA SNHG4 in tumorigenesis.

RESULTS

Compared to neighboring normal tissues, SNHG4 is significantly dysregulated in various tumor tissues. SNHG4 upregulation is mainly associated with advanced tumor stage, tumor size, TNM stage, and decreased overall survival. In addition, aberrant SNHG4 expression promotes cell proliferation, metastasis, migration, and invasion of cancer cells.

CONCLUSION

SNHG4 may serve as a new therapeutic target and prognostic biomarker in patients with cancer.

Competing Endogenous RNA (ceRNA) Networks and Splicing Switches in Cervical Cancer: HPV Oncogenesis, Clinical Significance and Therapeutic Opportunities

Cervical cancer (CC) is the primary cause of female cancer fatalities in low-middle-income countries (LMICs). Persistent infections from the human papillomavirus (HPV) can result in cervical cancer. However, numerous different factors influence the development and progression of cervical cancer. Transcriptomic knowledge of the mechanisms with which HPV causes cervical cancer pathogenesis is growing. Nonetheless, there is an existing gap hindering the development of therapeutic approaches and the improvement of patient outcomes. Alternative splicing allows for the production of numerous RNA transcripts and protein isoforms from a single gene, increasing the transcriptome and protein diversity in eukaryotes. Cancer cells exhibit astounding transcriptome modifications by expressing cancer-specific splicing isoforms. High-risk HPV uses cellular alternative splicing events to produce viral and host splice variants and proteins that drive cancer progression or contribute to distinct cancer hallmarks. Understanding how viruses utilize alternative splicing to drive pathogenesis and tumorigenesis is essential. Although research into the role of miRNAs in tumorigenesis is advancing, the function of other non-coding RNAs, including lncRNA and circRNA, has been understudied. Through their interaction with mRNA, non-coding RNAs form a network of competing endogenous RNAs (ceRNAs), which regulate gene expression and promote cervical cancer development and advancement. The dysregulated expression of non-coding RNAs is an understudied and tangled process that promotes cervical cancer development. This review will present the role of aberrant alternative splicing and immunosuppression events in HPV-mediated cervical tumorigenesis, and ceRNA network regulation in cervical cancer pathogenesis will also be discussed. Furthermore, the therapeutic potential of splicing disruptor drugs in cervical cancer will be deliberated.

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.

HK2 Is a Crucial Downstream Regulator of miR-148a for the Maintenance of Sphere-Forming Property and Cisplatin Resistance in Cervical Cancer Cells

The acquisition of cancer stem-like properties is believed to be responsible for cancer metastasis and therapeutic resistance in cervical cancer (CC). CC tissues display a high expression level of hexokinase 2 (HK2), which is critical for the proliferation and migration of CC cells. However, little is known about the functional role of HK2 in the maintenance of cancer stem cell-like ability and cisplatin resistance of CC cells. Here, we showed that the expression of HK2 is significantly elevated in CC tissues, and high HK2 expression correlates with poor prognosis. HK2 overexpression (or knockdown) can promote (or inhibit) the sphere-forming ability and cisplatin resistance in CC cells. In addition, HK2-overexpressing CC cells show enhanced expression of cancer stem cell-associated genes (including SOX2 and OCT4) and drug resistance-related gene MDR1. The expression of HK2 is mediated by miR-145, miR-148a, and miR-497 in CC cells. Overexpression of miR-148a is sufficient to reduce sphere formation and cisplatin resistance in CC cells. Our results elucidate a novel mechanism through which miR-148a regulates CC stem cell-like properties and chemoresistance by interfering with the oncogene HK2, providing the first evidence that dysregulation of the miR-148a/HK2 signaling plays a critical role in the maintenance of sphere formation and cisplatin resistance of CC cells. Our findings may guide future studies on therapeutic strategies that reverse cisplatin resistance by targeting this pathway.

Long noncoding RNA SNHG4: a novel target in human diseases

Recently, long noncoding RNAs (lncRNAs) have attracted great attention from researchers. LncRNAs are non-protein-coding RNAs of more than 200 nucleotides in length. Multiple studies have been published on the relationship between lncRNA expression and the progression of human diseases. LncRNA small nucleolar RNA host gene 4 (SNHG4), a member of the lncRNA SNHG family, is abnormally expressed in a variety of human diseases, including gastric cancer, renal cell carcinoma, glioblastoma, neuroblastoma, prostate cancer, colorectal cancer, osteosarcoma, cervical cancer, liver cancer, lung cancer, non-small-cell lung cancer, neonatal pneumonia, diabetic retinopathy, neuropathic pain, acute cerebral infarction, acute myeloid leukaemia, and endometriosis. In this paper, the structure of SNHG4 is first introduced, and then studies in humans, animal models and cells are summarized to highlight the expression and function of SNHG4 in the above diseases. In addition, the specific mechanism of SNHG4 as a competing endogenous RNA (ceRNA) is discussed. The findings indicate that SNHG4 can be used as a biomarker for disease prognosis evaluation and as a potential target for disease diagnosis and treatment.

The Biological Significance of Long noncoding RNAs Dysregulation and their Mechanism of Regulating Signaling Pathways in Cervical Cancer

Despite the remarkable decrease in cervical cancer incidence due to the availability of the HPV vaccine and implementation of screening programs for early detection in developed countries, this cancer remains a major health problem globally, especially in developing countries where most of the cases and mortality occur. Therefore, more understanding of molecular mechanisms of cervical cancer development might lead to the discovery of more effective diagnosis and treatment options. Research on long noncoding RNAs (lncRNAs) demonstrates the important roles of these molecules in many physiological processes and diseases, especially cancer. In the present review, we discussed the significance of lncRNAs altered expression in cervical cancer, highlighting their roles in regulating highly conserved signaling pathways, such as mitogen-activated protein kinase (MAPK), Wnt/β-catenin, Notch, and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathways and their association with the progression of cervical cancer in order to bring more insight and understanding of this disease and their potential implications in cancer diagnosis and therapy.

Analysis of m6A-Related lncRNAs for Prognosis Value and Response to Immune Checkpoint Inhibitors Therapy in Hepatocellular Carcinoma

Introduction

N6-methyladenosine (m6A) modification and long non-coding RNAs (lncRNAs) play pivotal roles in the progression of hepatocellular carcinoma (HCC). However, how their interaction is involved in the prognostic value of HCC and immune checkpoint inhibitors (ICIs) therapy remains unclear.

Methods

The RNA sequencing and clinical data of HCC patients were collected from TCGA database. The prognostic m6A-related lncRNAs were screened out with Pearson correlation test, univariate Cox analysis and least absolute shrinkage and selection operator (LASSO) Cox regression. Patients with HCC were classified into 2 subtypes by consensus clustering. Survival analyses were performed to assess the prognostic value of different clusters and risk models. Potential tumor correlated biological pathways correlated with different clusters were explored through gene set enrichment analysis. We also identified the relationship of the risk model and clusters with response to immune checkpoint inhibitors (ICIs) therapy and tumor microenvironment (TME). Furthermore, the prognostic value of the 9 m6A-related lncRNAs was validated in the external cohort. Finally, the role of SNHG4 was explored by silencing and overexpression of SNHG4 through conducting proliferation, migration and invasion experiments.

Results

Patients from 2 clusters and different risk groups based on m6A-related lncRNAs had significantly different clinicopathological characteristics and overall survival outcomes. Tumor-correlated biological pathways were found to be correlated with Cluster 2 through GSEA. Moreover, we found that patients from different clusters and risk groups expressed higher levels of immune checkpoint genes and had distinct TME and different responses for ICIs therapy. Prognostic value of this risk model was further confirmed in the external cohort. Finally, consistent with the discovery, SNHG4 played an oncogenic role in vitro.

Conclusion

Our study demonstrated that the 9 m6A-related lncRNA signature may serve as a novel predictor in the prognosis of HCC and optimize (ICIs) therapy. SNHG4 plays an oncogenic role in HCC.

Competing Endogenous RNAs in Cervical Carcinogenesis: A New Layer of Complexity

MicroRNAs (miRNAs) regulate gene expression by binding to complementary sequences within target mRNAs. Apart from working ‘solo’, miRNAs may interact in important molecular networks such as competing endogenous RNA (ceRNA) axes. By competing for a limited pool of miRNAs, transcripts such as long noncoding RNAs (lncRNAs) and mRNAs can regulate each other, fine-tuning gene expression. Several ceRNA networks led by different lncRNAs—described here as lncRNA-mediated ceRNAs—seem to play essential roles in cervical cancer (CC). By conducting an extensive search, we summarized networks involved in CC, highlighting the major impacts of such dynamic molecular changes over multiple cellular processes. Through the sponging of distinct miRNAs, some lncRNAs as HOTAIR, MALAT1, NEAT1, OIP5-AS1, and XIST trigger crucial molecular changes, ultimately increasing cell proliferation, migration, invasion, and inhibiting apoptosis. Likewise, several lncRNAs seem to be a sponge for important tumor-suppressive miRNAs (as miR-140-5p, miR-143-3p, miR-148a-3p, and miR-206), impairing such molecules from exerting a negative post-transcriptional regulation over target mRNAs. Curiously, some of the involved mRNAs code for important proteins such as PTEN, ROCK1, and MAPK1, known to modulate cell growth, proliferation, apoptosis, and adhesion in CC. Overall, we highlight important lncRNA-mediated functional interactions occurring in cervical cells and their closely related impact on cervical carcinogenesis.

LncRNA-NNT-AS1 contributes to the progression of glioma by miR-582-5p/EZH2 axis

Increasing studies have shown that long non-coding RNAs (lncRNAs) had crucial regulatory roles in many diseases. Nevertheless, the biological relevance and mechanisms of the NNT-AS1 in gliom remain poorly understood. In the present study, NNT-AS1 expression was up-regulated in the glioma cell lines. Functional assays demonstrated that depletion of NNT-AS1 could notably suppress the proliferation, migration, invasion and EMT of U87MG and A172 cells. In addition, miR-582-5p was predicted to be a target of NNT-AS1 and EZH2 was predicted to be a target of miR-582-5p by bioinformatics software, which was further confirmed by luciferase reporter assay. Additionally, results of recue assays proofed that NNT-AS1/miR-582-5p/EZH2 axis aggravated the malignant behaviors of glioma. Ultimately, our findings revealed that NNT-AS1 contributes to progression via targeting miR-582-5p/EZH2 axis, revealing NNT-AS1 as a latent effective target for the diagnosis and treatment of glioma patients.

Long Noncoding RNA Small Nucleolar Host Gene: A Potential Therapeutic Target in Urological Cancers

The incidence of urological cancer has been gradually increasing in the last few decades. However, current diagnostic tools and treatment strategies continue to have limitations. Substantial evidence shows that long noncoding RNAs (lncRNAs) play essential roles in carcinogenesis and the progression, treatment response and prognosis of multiple human cancers, including urological cancers, gastrointestinal tumours, reproductive cancers and respiratory neoplasms. LncRNA small nucleolar RNA host genes (SNHGs), a subgroup of lncRNAs, have been found to be dysregulated in tumour cell biology. In this review, we summarize the impacts of lncRNA SNHGs in urological malignancies and the underlying mechanisms.

lncRNA SNHG4 modulates colorectal cancer cell cycle and cell proliferation through regulating miR-590-3p/CDK1 axis

Colorectal cancer (CRC) is a prevalent malignancy worldwide. The development of genome sequencing technology has allowed the discovery that epigenetic regulation might play a critical role in CRC tumorigenesis. In the present study, we found that the long noncoding RNA (lncRNA) SNHG4 was dramatically increased in CRC tissue samples and cell lines based on both publicly available and experimental data. SNHG4 knockdown suppressed the viability and colony formation capacity of CRC cells. The expression of CDK1 was considerably increased in CRC tissue samples and cells and had a positive correlation with the expression of SNHG4 in CRC. SNHG4 silencing not only caused S phase cell cycle arrest but also significantly downregulated the CDK1, cyclin B1, and cyclin A2 protein levels in CRC cells. miR-590-3p simultaneously bound to SNHG4 and CDK1. miR-590-3p functioned to inhibit CDK1 expression. miR-590-3p overexpression exerted the same effects on the CRC cell phenotype as SNHG4 knockdown. The effects of si-SNHG4 on CRC cells were significantly reversed by anti-miR-590-3p, indicating that SNHG4 relieved the miR-590-3p-induced inhibition of CDK1 by acting as a competing endogenous RNA (ceRNA). In vivo, SNHG4 silencing inhibited subcutaneously transplanted tumor growth and decreased cell cycle marker levels, whereas miR-590-3p inhibition exerted the opposite effects. The in vivo effects of SNHG4 silencing were also reversed by miR-590-3p inhibition. The SNHG4/miR-590-3p/CDK1 axis influences the cell cycle to modulate CRC cell proliferation and subcutaneously transplanted tumor growth. Further application of this axis still requires analysis using more animal models and clinical investigations.

Bcl-2 Is Involved in Cardiac Hypertrophy through PI3K-Akt Pathway

Cardiac hypertrophy (CH) is a common cause of sudden cardiac death and heart failure, resulting in a significant medical burden. The present study is aimed at exploring potential CH-related pathways and the key downstream effectors. The gene expression profile of GSE129090 was obtained from the Gene Expression Omnibus database (GEO), and 1325 differentially expressed genes (DEGs) were identified, including 785 upregulated genes and 540 downregulated genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Reactome pathway enrichment analysis of DEGs were then performed. Although there were no pathways enriched by downregulated genes, many CH-related pathways were identified by upregulated genes, including PI3K-Akt signaling pathway, extracellular matrix- (ECM-) receptor interaction, regulation of actin cytoskeleton, and hypertrophic cardiomyopathy (HCM). In the deeper analysis of PI3K-Akt signaling pathway, we found all the signaling transduction pointed to B cell lymphoma-2- (Bcl-2-) mediated cell survival. We then demonstrated that PI3K-Akt signaling pathway was indeed activated in cardiac hypertrophy. Furthermore, no matter LY294002, an inhibitor of the PI3K/AKT signaling pathway, or Venetoclax, a selective Bcl-2 inhibitor, protected against cardiac hypertrophy. In conclusion, these data indicate that Bcl-2 is involved in cardiac hypertrophy as a key downstream effector of PI3K-Akt signaling pathway, suggesting a potential therapeutic target for the clinical management of cardiac hypertrophy.

Long noncoding RNA MAGI2-AS3 inhibits bladder cancer progression through MAGI2/PTEN/epithelial-mesenchymal transition (EMT) axis

BACKGROUND

Long noncoding RNA (lncRNA) are critical regulators of tumor progression.

OBJECTIVE

To determine how the lncRNA membrane associated guanylate kinase, WW and PDZ domain-containing 2 (MAG12) antisense RNA 3 (MAGI2-AS3) and the phosphatase and tensin homolog (PTEN) gene function in regulating bladder cancer (Bca) progression.

METHODS

Total RNA from 80 Bca tissues and 30 paired para-cancerous tissues from patients was sequentially extracted, quantified, purified, and reverse transcribed using RT-PCR. A library was constructed and sequenced. Four Bca cell lines and a normal urothelial cell line were transfected with lentiviral plasmids, and cell migration and invasion were assayed in vitro. An orthotopic mouse model of Bca was created for in vivo studies.

RESULTS

MAGI2-AS3 expression was significantly downregulated in Bca, compared with normal tissues, and negatively associated with tumor stage and a poor prognosis. MAGI2-AS3 and its sense RNA MAGI2 showed significant and positive correlation. The expression of MAGI2 and its downstream gene, PTEN, increased in Bca cells overexpressing MAGI2-AS3, and interference by MAGI2 expression reversed the migration and invasion inhibited by MAGI2-AS3 overexpression.

CONCLUSION

MAGI2-AS3 overexpression inhibited Bca cell progression by regulating the MAGI2/PTEN/epithelial-mesenchymal transition, offering novel insights into the mechanism of Bca progression.

The long non-coding RNA SNHG4/microRNA-let-7e/KDM3A/p21 pathway is involved in the development of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is a foremost cause of malignancy-associated mortality globally. Recent studies have emphasized long non-coding RNAs (lncRNAs) as important biomarkers with diagnostic and therapeutic potential in regard to NSCLC. This study aimed to elucidate the functional role of lncRNA small nucleolar RNA host gene 4 (SNHG4) in NSCLC. Initially, 50 paired cancerous and noncancerous tissues were obtained from NSCLC patients. Human NSCLC H1299 cells were assayed to evaluate viability, colony formation, invasion, migration, cycle arrest, and apoptosis via Cell Counting Kit-8 (CCK-8), plate clone formation, and transwell invasion assays, as well as a scratch test and flow cytometry. A dual-luciferase reporter gene assay was used to examine lncRNA SNHG4 binding with miR-let-7e and miR-let-7e binding with lysine demethylase 3A (KDM3A). H1299 cells were xenografted into nude mice. lncRNAs SNHG4 and KDM3A were both upregulated in NSCLC tissues. The knockdown of lncRNA SNHG4 or KDM3A inhibited H1299 cell viability, colony formation, invasion, migration, and cycle progression while inducing apoptosis. lncRNA SNHG4 was found to bind to miR-let-7e that negatively targeted KDM3A. KDM3A inhibited p53-K372me1, thus reducing p21 expression. The NSCLC development was inhibited by downregulating lncRNA SNHG4 in nude mice. Taken together, the key findings of the current study demonstrate a novel lncRNA SNHG4/let-7e/KDM3A/p21 axis in NSCLC, highlighting a promising therapeutic target for NSCLC.

The PARP Inhibitor Olaparib Modulates the Transcriptional Regulatory Networks of Long Non-Coding RNAs during Vasculogenic Mimicry

In highly metastatic tumors, vasculogenic mimicry (VM) involves the acquisition by tumor cells of endothelial-like traits. Poly-(ADP-ribose) polymerase (PARP) inhibitors are currently used against tumors displaying BRCA1/2-dependent deficient homologous recombination, and they may have antimetastatic activity. Long non-coding RNAs (lncRNAs) are emerging as key species-specific regulators of cellular and disease processes. To evaluate the impact of olaparib treatment in the context of non-coding RNA, we have analyzed the expression of lncRNA after performing unbiased whole-transcriptome profiling of human uveal melanoma cells cultured to form VM. RNAseq revealed that the non-coding transcriptomic landscape differed between olaparib-treated and non-treated cells: olaparib significantly modulated the expression of 20 lncRNAs, 11 lncRNAs being upregulated, and 9 downregulated. We subjected the data to different bioinformatics tools and analysis in public databases. We found that copy-number variation alterations in some olaparib-modulated lncRNAs had a statistically significant correlation with alterations in some key tumor suppressor genes. Furthermore, the lncRNAs that were modulated by olaparib appeared to be regulated by common transcription factors: ETS1 had high-score binding sites in the promoters of all olaparib upregulated lncRNAs, while MZF1, RHOXF1 and NR2C2 had high-score binding sites in the promoters of all olaparib downregulated lncRNAs. Finally, we predicted that olaparib-modulated lncRNAs could further regulate several transcription factors and their subsequent target genes in melanoma, suggesting that olaparib may trigger a major shift in gene expression mediated by the regulation lncRNA. Globally, olaparib changed the lncRNA expression landscape during VM affecting angiogenesis-related genes.

lncRNA SNHG4 promotes cell proliferation, migration, invasion and the epithelial-mesenchymal transition process via sponging miR-204-5p in gastric cancer

Long non-coding (lnc)RNAs and microRNAs (miRNAs/miRs) have physiological and pathological functions in various diseases, including gastric cancer (GC). The current study explored the association between lncRNA small nucleolar RNA host gene 4 (SNHG4) and miR-148a-3p, and their functions in GC cells. SNHG4 expression and overall survival data were analyzed using bioinformatics, and the interaction of SNHG4 and miR-148a-3p was predicted using starBase and confirmed via a dual-luciferase reporter assay. Cell viability, colony formation ability and apoptosis rate were detected using Cell Counting Kit-8, colony formation and flow cytometry assays, respectively. Cell migration and invasion were determined via wound-healing and Transwell assays. mRNA and protein expression levels were determined via reverse transcription-quantitative PCR and western blotting. The results demonstrated that in GC tissues and cell lines, SNHG4 was highly expressed, while miR-204-5p expression was decreased, and that the expression levels of SNHG4 and miR-204-5p were negatively correlated. The downregulated expression of SNHG4 decreased the effects of miR-204-5p inhibitor on promoting cell proliferation, migration, invasion and epithelial-mesenchymal transition, but enhanced the inhibitory effect of miR-204-5p on GC cell apoptosis. The findings of the current study revealed the potential mechanism of the SNHG4-miR-204-5p pathway in GC, which may be conducive to the development of novel drugs against GC growth.

Long noncoding RNA SNHG4 promotes renal cell carcinoma tumorigenesis and invasion by acting as ceRNA to sponge miR-204-5p and upregulate RUNX2

Background

Long noncoding RNAs (lncRNAs) are involved in the tumorigenesis and progression of human cancers, including renal cell carcinoma (RCC). Small nucleolar RNA host gene 4 (SNHG4) is reported to play an essential role in tumor growth and progression. However, the molecular mechanisms and function of SNHG4 in RCC remain undocumented.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to examine expression levels of SNHG4 in RCC tissue samples and cell lines. Cell counting kit-8, western blotting, activities of caspase-3, -8, and -9, wound-healing, and transwell invasion assays were performed to explore cell proliferation, apoptosis, migration, and invasion. The interaction among SNHG4, miR-204-5p, and RUNX2 was verified by bioinformatic analysis, a luciferase gene report, qRT-PCR, western blot analysis, and RNA immunoprecipitation assays. Xenograft mouse models were carried out to examine the role of SNHG4 in RCC in vivo.

Results

SNHG4 was highly expressed in RCC tissue samples and cell lines, and its upregulation was significantly involved in node involvement, distant metastasis, and reduced overall and relapse-free survival of patients with RCC. SNHG4 acted as an oncogenic lncRNA with promoted RCC cell proliferation, migration, invasion, and inhibited apoptosis. SNHG4 boosted tumor growth in xenograft mouse models. Mechanistically, SNHG4 functioned as a competing endogenous RNA (ceRNA) for sponging miR-204-5p, leading to the upregulation of its target RUNX2 to promote RCC cell proliferation and invasion.

Conclusion

SNHG4 and miR-204-5p might be indicated in RCC progression via RUNX2, suggesting the potential use of SNHG4/miR-204-5p/RUNX2 axis in RCC treatment.

LncRNA SNHG4 Attenuates Inflammatory Responses by Sponging miR-449c-5p and Up-Regulating STAT6 in Microglial During Cerebral Ischemia-Reperfusion Injury

Background

Inflammatory response mediated by microglia plays a key role in cerebral ischemia-reperfusion injury. This study intends to probe the role of lncRNA SNHG4 in regulating the inflammatory response of the microglia during cerebral ischemia reperfusion.

Materials and Methods

Blood samples and cerebrospinal fluid samples were collected from acute cerebral infarction (ACI) patients and healthy controls. The middle cerebral artery occlusion (MCAO) models were constructed with rats. LPS induction and oxygen-glucose deprivation methods were respectively applied to simulate the activation of microglia in vitro. qRT-PCR was employed to determine the expressions of SNHG4, miR-449c-5p and related inflammatory factors in vivo and in vitro. The inflammatory responses of the microglia subject to the varied expressions of SNHG4 and miR-449c-5p were detected. Luciferase assays were conducted to verify the crosstalk involving SNHG4, miR-449c-5p and STAT6.

Results

Compared with the control group, the expression of SNHG4 derived from the samples of ACI patients and the microglia of MCAO group were remarkably down-regulated, but the expression of miR-449c-5p was dramatically up-regulated. Overexpression of SNHG4 and knock-down of miR-449c-5p could inhibit the expression of pro-inflammatory cytokine in the microglia and promote the expression of anti-inflammatory factors. Meanwhile, the phospho-STAT6 was up-regulated, whereas the knock-down of SNHG4 and over-expression of miR-449c-5p in microglia had the opposite effects. Luciferase assay confirmed that SNHG4 could target miR-449c-5p, while miR-449c-5p could target STAT6.

Conclusion

SNHG4 can regulate STAT6 and repress inflammation by adsorbing miR-449c-5p in microglia during cerebral ischemia-reperfusion injury.

A three-miRNA panel in serum as a noninvasive biomarker for colorectal cancer detection

BACKGROUND

Circulating miRNAs have been proved to be promising biomarkers for disease detection in recent years. The present study aimed at exploring available serum miRNA biomarkers for the detection of colorectal cancer.

METHODS

A three-phase study was performed to select and validate candidate miRNAs with significant dysregulation in colorectal cancer using quantitative reverse transcription-polymerase chain reaction. This study recruited 137 colorectal cancer patients and 145 healthy controls. The diagnostic values of miRNAs were evaluated by receiver operating characteristic analysis. Bioinformatics analyses were utilized to predict target genes of miRNAs, and to conduct functional annotation and enrichment.

RESULTS

miR-30e-3p, miR-31-5p, miR-34b-3p and miR-146a-5p, miR-148a-3p and miR-192-5p were significantly dysregulated in colorectal cancer serum when compared with healthy controls. The panel composed of miR-30e-3p, miR-146a-5p, and miR-148a-3p exhibited strong diagnostic ability. The area under the receiver operating characteristic curve of the three-miRNA panel was 0.883, with a sensitivity of 0.800 and specificity of 0.787.

CONCLUSION

The present study identified a three-miRNA panel in serum with a strong diagnostic ability of colorectal cancer, which may be able to serve as a novel noninvasive biomarker for colorectal cancer detection.

LncRNA SNHG4 promotes the increased growth of endometrial tissue outside the uterine cavity via regulating c-Met mediated by miR-148a-3p

Long noncoding RNAs (lncRNAs) modulate endometriosis. The current study investigated the mechanisms and effects of SNHG4 on endometriosis. The qRT-PCR was conducted to examine the miR-148a-3p and SNHG4 expressions in endometriosis tissues. The 5-ethynyl-2'-deoxyuridine incorporation assay and 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide assay were used to measure the rate of cell proliferation. The association between miR-148a-3p, SNHG4 and c-Met was confirmed via bioinformatical approach and luciferase reporter gene assay. Also, the function of SNHG4 on the growth of endometriotic lesions was investigated in vivo. The SNHG4 expression was considerably upregulated in endometriosis tissues, whereas the level of miR-148a-3p expression was reduced. In addition, SNHG4 can be considered as ceRNAs that bind miR-148a-3p and rise the proliferation activity of HESCs by downregulating miR-148a-3p. Furthermore, silencing SNHG4 could downregulate the c-Met level by enhancing miR-148a-3p expression, and finally inhibiting endometriosis development in vivo. LncRNA SNHG4 promotes the increased growth of endometrial tissue outside the uterine cavity via regulating c-Met mediated by miR-148a-3p, which may be used as diagnostic biomarker as well as molecular target in the treatment of endometriosis.

MicroRNA-148a-3p inhibits cancer progression and is a novel screening biomarker for gastric cancer

PURPOSE

Dysregulation of miR-148a-3p in gastric cancer was reported. However, the diagnostic potential and biological function of miR-148a-3p in gastric cancer progression is not fully studied.

METHODS

Bioinformatics analysis and RT-qPCR assay were performed to analyze the expression of miR-148a-3p in gastric cancer tissues and plasma of gastric cancer patients. Receiver operating characteristic curve analysis was performed to analyze the diagnostic value of miR-148a-3p. In vitro proliferation, apoptosis, migration, invasion, sphere formation assay and Western blotting assay were performed to evaluate the biological function of miR-148a-3p in gastric cancer progression.

RESULTS

miR-148a-3p was significantly down-regulated in both gastric cancer patients' tissue and plasma samples. Plasma miR-148a-3p showed promising efficacy for gastric cancer diagnosis. Overexpression of miR-148a-3p could inhibit the proliferative phenotype, metastatic phenotype, and cancer stem-like properties of gastric cancer cells.

CONCLUSIONS

miR-148a-3p inhibits cancer progression and is a novel diagnostic biomarker for gastric cancer.

Proteomic analysis of human cervical adenocarcinoma mucus to identify potential protein biomarkers

Background

Cervical cancer is the most common gynecological cancer, encompassing cervical squamous cell carcinoma, adenocarcinoma, and other epithelial tumors. There are many diagnostic methods to detect cervical cancers but no precision screening tool for cervical adenocarcinoma at present.

Material and methods

The cervical mucus from three normal cervices (Ctrl), three endocervical adenocarcinoma (EA), and three cervical adenocarcinoma in situ (AIS) was collected for proteomic analysis. The proteins were screened using liquid chromatography-mass spectrometry analysis (LC-MS). The biological function of the differently expressed proteins were predicted by Gene Ontology (GO).

Results

A total of 711 proteins were identified, including 237 differently expressed proteins identified in EA/Ctrl comparison, 256 differently expressed proteins identified in AIS/Ctrl comparison, and 242 differently expressed proteins identified in AIS/EA comparison (up-regulate ≥ 1.5 or down-regulate ≤ 0.67). Functional annotation was performed using GO analysis on 1,056 differently expressed proteins to identify those that may impact cervical cancer, such as heme protein myeloperoxidase, which is involved in the immune process, and APOA1, which is associated with lipid metabolism.

Conclusion

We used proteomic analysis to screen out differently expressed proteins from normal cervical mucus and cervical adenocarcinoma mucus samples. These differently expressed proteins may be potential biomarkers for the diagnosis and treatment of cervical adenocarcinoma but require additional study.

LncRNA SNHG4 regulates miR-138/c-Met axis to promote the proliferation of glioblastoma cells

LncRNA SNHG4 has been reported to be an oncogenic lncRNA in osteosarcoma. Our preliminary analysis of the cancer genome atlas dataset revealed the upregulation of SNHG4 in glioblastoma (GBM). In this study, we confirmed the upregulation of SNHG4 in GBM tissues collected from GBM patients. In addition, lower survival rate of GBM patients was observed in patients with high SNHG4 expression level. SNHG4 can directly interact with miR-138, while SNHG4 expression was no altered after miR-138 overexpression. Interestingly, SNHG4 overexpression led to the upregulation of c-Met, a target of miR-138. Cell counting kit-8 assay showed that miR-138 overexpression resulted in decreased proliferation rate of GBM cells. SNHG4 and c-Met overexpression played opposite roles and reduced the effects of miR-138. Therefore, SNHG4 regulates miR-138/c-Met axis to promote the proliferation of GBM cells.

Long noncoding RNA PITPNA-AS1 promotes cervical cancer progression through regulating the cell cycle and apoptosis by targeting the miR-876-5p/c-MET axis

Cervical cancer is a common tumor type and a leading cause of tumor death among female in the world. However, the molecular mechanisms revealing the cervical cancer progression have not been fully investigated. Long noncoding RNA (LncRNA) PITPNA-AS1 is a newly found lncRNA, showing the promoting role in tumor growth. But its effects on cervical cancer development still remain unknown. In the study, we found that PITPNA-AS1 was markedly increased in human cervical cancer tissues and cell lines. PITPNA-AS1 over-expression elevated the proliferation of cervical cancer cells, whereas PITPNA-AS1 knockdown reduced the cell proliferation. Moreover, PITPNA-AS1 knockdown markedly accelerated the G0/G1 and reduced the G2/M phase transitions through decreasing the cyclin-dependent kinase (CDK)-2/4/6 and CyclinD1 expression levels. In addition, apoptosis was significantly induced by PITPNA-AS1 knockdown in cervical cancer cells. Importantly, PITPNA-AS1 was identified as the sponge of miR-876-5p, and a negative correlation was detected between PITPNA-AS1 and miR-876-5p in cervical cancer samples. Moreover, tyrosine-protein kinase MET (c-MET) was identified to be a down-streaming target gene of miR-876-5p in cervical cancer cells. PITPNA-AS1 meditated the effects of c-MET on the proliferation, apoptosis and cell cycle in cervical cancer cells by adsorbing miR-876-5p. In summary, targeting the PITPNA-AS1-associated signaling could be a therapeutic strategy for the treatment of cervical cancer.

Crosstalk Mechanisms Between HGF/c-Met Axis and ncRNAs in Malignancy

Several lines of evidence have confirmed the magnitude of crosstalk between HGF/c-Met axis (hepatocyte growth factor and its high-affinity receptor c-mesenchymal-epithelial transition factor) and non-coding RNAs (ncRNAs) in tumorigenesis. Through activating canonical or non-canonical signaling pathways, the HGF/c-Met axis mediates a range of oncogenic processes such as cell proliferation, invasion, apoptosis, and angiogenesis and is increasingly becoming a promising target for cancer therapy. Meanwhile, ncRNAs are a cluster of functional RNA molecules that perform their biological roles at the RNA level and are essential regulators of gene expression. The expression of ncRNAs is cell/tissue/tumor-specific, which makes them excellent candidates for cancer research. Many studies have revealed that ncRNAs play a crucial role in cancer initiation and progression by regulating different downstream genes or signal transduction pathways, including HGF/c-Met axis. In this review, we discuss the regulatory association between ncRNAs and the HGF/c-Met axis by providing a comprehensive understanding of their potential mechanisms and roles in cancer development. These findings could reveal their possible clinical applications as biomarkers for therapeutic interventions.