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.

In vitro Anti-malignant Property of PCMT1 Silencing and Identification of the SNHG16/miR-195/PCMT1 Regulatory Axis in Breast Cancer Cells

BACKGROUND

Protein L-isoaspartate (D-aspartate) O-methyltransferase (PCMT1) is a highly conserved protein repair enzyme that participates in regulating the progression of human cancers. We therefore studied the function and the related mechanisms of PCMT1 in breast cancer cells.

METHODS

Expression profile and prognostic analysis of PCMT1 in breast cancer patients were analyzed using online databases. PCMT1 expression in breast cancer cells was detected by western blot analysis. Cell proliferation was determined by CCK-8 and colony formation assays. Apoptosis was evaluated using flow cytometry analysis and caspase-3/7 activity assay. Cell invasion was assessed by Transwell invasion assay. The small nucleolar RNA host gene 16 (SNHG16)/miR-195/PCMT1 regulatory axis was identified using bioinformatics analysis.

RESULTS

PCMT1 expression was increased in breast cancer tissues and cells. High PCMT1 expression was correlated with poor prognosis in breast cancer patients. PCMT1 knockdown suppressed cell proliferation and colony formation ability in breast cancer cells. Moreover, PCMT1 knockdown induced apoptosis and restrained the invasive ability in breast cancer cells. PCMT1 overexpression increased the proliferative and invasive abilities of breast cancer cells. miR-195 was identified as the unique upstream miRNA of PCMT1. SNHG16 was identified as the unique upstream lncRNA of miR-195. SNHG16 knockdown downregulated PCMT1 by increasing miR-195 expression. Breast cancer cell proliferation was regulated by the SNHG16/miR-195/PCMT1 axis.

CONCLUSION

PCMT1 silencing inhibited cell proliferation and invasion and induced apoptosis in breast cancer cells and the SNHG16/miR-195/PCMT1 regulatory axis might serve as a potential therapeutic target for breast cancer.

Oncogenic role and potential regulatory mechanism of fatty acid binding protein 5 based on a pan-cancer analysis

As one member of fatty acid binding proteins (FABPs), FABP5 makes a contribution in the occurrence and development of several tumor types, but existing analysis about FABP5 and FABP5-related molecular mechanism remains limited. Meanwhile, some tumor patients showed limited response rates to current immunotherapy, and more potential targets need to be explored for the improvement of immunotherapy. In this study, we made a pan-cancer analysis of FABP5 based on the clinical data from The Cancer Genome Atlas database for the first time. FABP5 overexpression was observed in many tumor types, and was statistically associated with poor prognosis of several tumor types. Additionally, we further explored FABP5-related miRNAs and corresponding lncRNAs. Then, miR-577-FABP5 regulatory network in kidney renal clear cell carcinoma as well as CD27-AS1/GUSBP11/SNHG16/TTC28-AS1-miR-22-3p-FABP5 competing endogenous RNA regulatory network in liver hepatocellular carcinoma were constructed. Meanwhile, Western Blot and reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) analysis were used to verify miR-22-3p-FABP5 relationship in LIHC cell lines. Moreover, the potential relationships of FABP5 with immune infiltration and six immune checkpoints (CD274, CTLA4, HAVCR2, LAG3, PDCD1 and TIGIT) were discovered. Our work not only deepens the understanding of FABP5's functions in multiple tumors and supplements existing FABP5-related mechanisms, but also provides more possibilities for immunotherapy.

LncRNA SNHG16 promotes development of oesophageal squamous cell carcinoma by interacting with EIF4A3 and modulating RhoU mRNA stability

Background

Numerous studies have revealed that long noncoding RNAs (lncRNAs) are closely related to the development of many diseases and carcinogenesis. However, their specific biological function and molecular mechanism in oesophageal squamous cell carcinoma (ESCC) remains unclear.

Methods

RNA-Seq was performed to determine the differential expressions of lncRNAs in ESCC, and the level of SNHG16 expression was detected in ESCC and intraepithelial neoplasia (IEN) samples. In vitro and in vivo experiments were performed to explore the role of SNHG16 and the interaction of EIF4A3 and Ras homologue family member U (RhoU) signalling.

Results

One hundred and seventy-five upregulated and 134 downregulated lncRNAs were identified by RNA-Seq. SNHG16 was highly expressed in ESCC and intraepithelial neoplasia (IEN) samples, and its expression level was correlated with tumour differentiation and T stage. Overexpression of SNHG16 can facilitate ESCC cell proliferation and metastasis. Mechanistically, we noticed that SNHG16 could bind RNA binding protein (RBP)-eukaryotic translation initiation factor (EIF4A3) and interact with it to form a complex. Importantly, the coalition of SNHG16 and EIF4A3 ultimately regulated Ras homologue family member U (RhoU). SNHG16 modulated RhoU expression by recruiting EIF4A3 to regulate the stability of RhoU mRNA. Knockdown of RhoU further alleviated the effect of the SNHG16 oncogene in ESCC cells.

Conclusions

The newly identified SNHG16–EIF4A3–RhoU signalling pathway directly coordinates the response in ESCC pathogenesis and suggests that SNHG16 is a promising target for potential ESCC treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00386-w.

miR-302a-3p Promotes Radiotherapy Sensitivity of Hepatocellular Carcinoma by Regulating Cell Cycle via MCL1

Background. The relationship between tumor suppressor gene miR-302a-3p and radiotherapy for hepatocellular carcinoma (HCC) remains unclear. This study intended to illustrate the molecular mechanism how miR-302a-3p regulated radiotherapy sensitivity of HCC. Methods. miR-302a-3p expression in HCC tissues and cells was examined by qRT-PCR. The effect of miR-302a-3p on HCC radiotherapy sensitivity were detected by CCK-8, colony formation, and flow cytometry assays. The expression levels of cell cycle-related proteins were detected by Western blot. The influence of miR-302a-3p on radiotherapy sensitivity of HCC was further investigated via cell cycle inhibitor (Caudatin) treatment. The target gene (MCL1) of miR-302a-3p was obtained by bioinformatics analysis, and their binding relationship was confirmed by RNA-binding protein immunoprecipitation assay. The mechanisms of miR-302a-3p regulating cell cycle and affecting radiotherapy sensitivity of HCC cells through MCL1 were further explored through the rescue experiments. Results. miR-302a-3p expression was remarkably reduced in radiotherapy-resistant tissues and cells of HCC. miR-302a-3p overexpression restored sensitivity of radiotherapy-resistant HCC cells to radiotherapy. Treatment with cell cycle inhibitor Caudatin could reverse suppressive effect of miR-302a-3p downregulation on sensitivity of HCC to radiotherapy. Additionally, miR-302a-3p could restrain MCL1 expression. In vitro cell assays further revealed that miR-302a-3p/MCL1 axis could enhance radiotherapy sensitivity of HCC cells by inducing G0/G1 arrest. Conclusions. miR-302a-3p facilitated radiotherapy sensitivity of HCC cells by regulating cell cycle via MCL1, which provided a new underlying target for radiotherapy resistance of HCC patients.

CircAGFG1 Promotes Osteosarcoma Progression and Stemness by Competing with miR-302a-3p to Upregulate the Expression of LATS2

This study aimed to investigate the effect of circRNA (circAGFG1) on the proliferation, migration, invasion, and cell stemness of osteosarcoma cells by targeting miR-302a to regulate LATS2. The expression of circAGFG1 in osteosarcoma cells and normal osteoblasts was detected by real-time fluorescent quantitative PCR (RT-qPCR). Cell proliferation, clone formation, and invasion were detected by CCK-8, clone formation, and cell invasion assays. In vivo tumor formation assay was used to detect the effect of circAGFG1 on tumor growth. The expression level of circAGFG1 was upregulated in osteosarcoma cells. The downregulation of circAGFG1 inhibited the proliferation, invasion, and migration of osteosarcoma cells. The overexpression of circAGFG1 enhanced the stemness of osteosarcoma cells. CircAGFG1 was specifically bound to miR-302a to regulate the expression activity of miR-302a. MiR-302a specifically bound to the 3'UTR of LATS2 and inhibited the expression of LATS2. The overexpression of miR-302a reversed the effect of circAGFG1 on the proliferation, invasion, and migration of osteosarcoma cells. CircAGFG1 regulated the expression of LATS2 by miR-302a, thereby regulating the proliferation, migration, and invasion of osteosarcoma cells.

New developments in the biology of fibroblast growth factors

The fibroblast growth factor (FGF) family is composed of 18 secreted signaling proteins consisting of canonical FGFs and endocrine FGFs that activate four receptor tyrosine kinases (FGFRs 1-4) and four intracellular proteins (intracellular FGFs or iFGFs) that primarily function to regulate the activity of voltage-gated sodium channels and other molecules. The canonical FGFs, endocrine FGFs, and iFGFs have been reviewed extensively by us and others. In this review, we briefly summarize past reviews and then focus on new developments in the FGF field since our last review in 2015. Some of the highlights in the past 6 years include the use of optogenetic tools, viral vectors, and inducible transgenes to experimentally modulate FGF signaling, the clinical use of small molecule FGFR inhibitors, an expanded understanding of endocrine FGF signaling, functions for FGF signaling in stem cell pluripotency and differentiation, roles for FGF signaling in tissue homeostasis and regeneration, a continuing elaboration of mechanisms of FGF signaling in development, and an expanding appreciation of roles for FGF signaling in neuropsychiatric diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology Congenital Diseases > Stem Cells and Development Cancer > Stem Cells and Development.

Correlation of small nucleolar RNA host gene 16 with acute respiratory distress syndrome occurrence and prognosis in sepsis patients

Background

Long noncoding RNA small nucleolar RNA host gene 16 (lnc‐SNHG16) regulates sepsis‐induced acute lung injury and inflammation, which is involved in the pathophysiology of acute respiratory distress syndrome (ARDS). The present study intended to explore the role of lnc‐SNHG16 as a potential biomarker indicating ARDS risk, disease severity, inflammation, and mortality in sepsis.

Methods

Peripheral blood mononuclear cell (PBMC) samples were collected from 160 sepsis patients within 24 hours after admission and 30 healthy controls (HCs). Then, lnc‐SNHG16 in PBMCs was detected by reverse transcription‐quantitative polymerase chain reaction. Sepsis patients were followed up until death or up to 28 days.

Results

lnc‐SNHG16 was declined in sepsis patients compared with HCs (p < 0.001). The incidence of ARDS was 27.5% among sepsis patients; meanwhile, sepsis patients with ARDS had higher mortality than those without ARDS (p < 0.001). Furthermore, lnc‐SNHG16 was declined in sepsis patients with ARDS compared to those without ARDS (p < 0.001); besides, higher lnc‐SNHG16 was independently correlated with declined ARDS occurrence in sepsis patients (p = 0.001), while primary respiratory infection and higher CRP were independently correlated with elevated ARDS occurrence in sepsis patients (both p < 0.05). Moreover, a negative correlation was found in lnc‐SNHG16 with history of diabetes, history of chronic obstructive pulmonary disease, and APACHE II and SOFA scores (all p < 0.05). Additionally, lnc‐SNHG16 was declined in sepsis deaths compared with survivors (p = 0.002), while it was not independently linked with sepsis mortality.

Conclusion

lnc‐SNHG16 correlates with lower ARDS occurrence and better prognosis in sepsis patients.

Long non-coding RNA small nucleolar RNA host genes: functions and mechanisms in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors of the digestive system, with a high degree of malignancy. Although treatment methods are constantly improving, the mortality of patients is still very high, and the small nucleolar RNA host gene (SNHG) plays an important role in the occurrence and development of cancer. It can activate downstream signaling molecules by acting on microRNA and microRNA target genes, promote the proliferation, invasion, and migration of HCC cells, and provide a new molecular target for the treatment of HCC. At present, the molecular mechanisms of HCC remain unclear. In this study, the mechanism and signaling pathway of SNHG in HCC are reviewed, which provides a theoretical basis for the clinical treatment of HCC.

LncRNA SNHG16 accelerates atherosclerosis and promotes ox-LDL-induced VSMC growth via the miRNA-22-3p/HMGB2 axis

Long non-coding RNAs (LncRNAs) are essential regulators in the occurrence and development of AS. Here we aim to explore the underlying molecular mechanism of LncRNA SNHG16 in regulating ox-LDL-induced VSMC proliferation, migration and invasion. After constructing AS in vivo and in vitro models, the expressions of SNHG16, miR-22-3p, HMBG2, proliferation- and metastasis-related proteins were determined by qRT-PCR and Western blot assays. Detection of serological lipids, H&E and Masson staining analysis were conducted to evaluate the AS injury in mice. The effects of ox-LDL treatment on VSMCs were examined by CCK-8, wound scratch and Transwell Chamber assays. The targeted relationship was measured by luciferase reporter and RIP assays. The results showed that SNHG16 and high-mobility group box 2 (HMGB2) expressions were increased while miRNA-22-3p expression was decreased in AS mice and ox-LDL-stimulated VSMCs. Functionally, sh-SNHG16 restrained ox-LDL-induced VSMC growth and migration. SNHG16 suppressed miRNA-22-3p expression by direct binding. Furthermore, in ox-LDL-treated VSMCs, miRNA-22-3p mimic prevented proliferation, migration, and invasion. Further explorations showed that HMGB2 was a target of miRNA-22-3p, SNHG16 upregulated HMGB2 levels by acting as a competing endogenous RNA (ceRNA) of miRNA-22-3p. More importantly, sh-HMGB2 partially reversed the effects of sh-SNHG16 together with miR-22-2p inhibitor on ox-LDL-induced VSMC proliferation, migration and invasion. Collectively, SNHG16 accelerated atherosclerotic plaque (AP) formation and enhanced ox-LDL-activated VSMCs proliferation and migration by miRNA-22-3p/HMGB2 axis.

A Review on the Role of Small Nucleolar RNA Host Gene 6 Long Non-coding RNAs in the Carcinogenic Processes

Being located on 17q25.1, small nucleolar RNA host gene 6 (SNHG16) is a member of SNHG family of long non-coding RNAs (lncRNA) with 4 exons and 13 splice variants. This lncRNA serves as a sponge for a variety of miRNAs, namely miR-520a-3p, miR-4500, miR-146a miR-16–5p, miR-98, let-7a-5p, hsa-miR-93, miR-17-5p, miR-186, miR-302a-3p, miR-605-3p, miR-140-5p, miR-195, let-7b-5p, miR-16, miR-340, miR-1301, miR-205, miR-488, miR-1285-3p, miR-146a-5p, and miR-124-3p. This lncRNA can affect activity of TGF-β1/SMAD5, mTOR, NF-κB, Wnt, RAS/RAF/MEK/ERK and PI3K/AKT pathways. Almost all studies have reported oncogenic effect of SNHG16 in diverse cell types. Here, we explain the results of studies about the oncogenic role of SNHG16 according to three distinct sets of evidence, i.e., in vitro, animal, and clinical evidence.

Heterogeneous graph attention network based on meta-paths for lncRNA-disease association prediction

MOTIVATION

Discovering long noncoding RNA (lncRNA)-disease associations is a fundamental and critical part in understanding disease etiology and pathogenesis. However, only a few lncRNA-disease associations have been identified because of the time-consuming and expensive biological experiments. As a result, an efficient computational method is of great importance and urgently needed for identifying potential lncRNA-disease associations. With the ability of exploiting node features and relationships in network, graph-based learning models have been commonly utilized by these biomolecular association predictions. However, the capability of these methods in comprehensively fusing node features, heterogeneous topological structures and semantic information is distant from optimal or even satisfactory. Moreover, there are still limitations in modeling complex associations between lncRNAs and diseases.

RESULTS

In this paper, we develop a novel heterogeneous graph attention network framework based on meta-paths for predicting lncRNA-disease associations, denoted as HGATLDA. At first, we conduct a heterogeneous network by incorporating lncRNA and disease feature structural graphs, and lncRNA-disease topological structural graph. Then, for the heterogeneous graph, we conduct multiple metapath-based subgraphs and then utilize graph attention network to learn node embeddings from neighbors of these homogeneous and heterogeneous subgraphs. Next, we implement attention mechanism to adaptively assign weights to multiple metapath-based subgraphs and get more semantic information. In addition, we combine neural inductive matrix completion to reconstruct lncRNA-disease associations, which is applied for capturing complicated associations between lncRNAs and diseases. Moreover, we incorporate cost-sensitive neural network into the loss function to tackle the commonly imbalance problem in lncRNA-disease association prediction. Finally, extensive experimental results demonstrate the effectiveness of our proposed framework.

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.

The Role of Fibroblast Growth Factor 19 in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common type of cancer and the third leading cause of cancer-related deaths worldwide. Liver resection or liver transplantation is the most effective therapy for HCC because drugs approved by the US Food and Drug Administration to treat patients with unresectable HCC have an unfavorable overall survival rate. Therefore, the development of biomarkers for early diagnosis and effective therapy strategies are still necessary to improve patient outcomes. Fibroblast growth factor (FGF) 19 was amplified in patients with HCC from various studies, including patients from The Cancer Genome Atlas. FGF19 plays a syngeneic function with other signaling pathways in primary liver cancer development, such as epidermal growth factor receptor, Wnt/β-catenin, the endoplasmic reticulum-related signaling pathway, STAT3/IL-6, RAS, and extracellular signal-regulated protein kinase, among others. The current review presents a comprehensive description of the FGF19 signaling pathway involved in liver cancer development. The use of big data and bioinformatic analysis can provide useful clues for further studies of the FGF19 pathway in HCC, including its application as a biomarker, targeted therapy, and combination therapy strategies.

The Clinical Prognostic Value of lncRNA SBF2-AS1 in Cancer Patients: A Meta-Analysis

Background:

The mortality and recurrence of patients with cancer is of high prevalence. SET-binding factor 2 (SBF2) antisense RNA1 (lncRNA-SBF2-AS1) is a promising long non-coding RNA. There is increasing evidence that SBF2-AS1 is abnormally expressed in various tumors and is associated with cancer prognosis. However, the identification of the effect of lncRNA SBF2-AS1 in tumors remains necessary.

Materials and Methods:

Up to November 2, 2020, electronic databases, including PubMed, Cochrane Library, EMBASE, Medline, and Web of Science, were searched. The results were evaluated by pooled odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs).

Results:

A total of 11 literatures on cancer patients were included for the present meta-analysis. The combined results revealed that high expression of SBF2-AS1 was significantly associated with unfavorable overall survival (OS) (HR = 1.48, 95% CI: 1.34-1.62, P < 0.00001) in a variety of cancers. In additional, the increase in SBF2-AS1 expression was also correlated with tumor size ((larger vs. smaller) OR = 2.34, 95% CI: 1.47-3.70, P = 0.0003), advanced TNM stage ((III/IV vs. I/II) OR = 2.78, 95% CI: 1.75-4.41, P < 0.0001), lymph node metastasis ((Positive vs. Negative) OR = 3.06, 95% CI: 1.93-4.86, P < 0.00001), and histological grade ((poorly vs. well/moderately) OR = 2.58, 95% CI: 1.47-4.52, P = 0.001) in patients with cancer. Furthermore, The Cancer Genome Atlas (TCGA) dataset valuated that SBF2-AS1 was upregulated in a variety of tumors, and predicted the worse prognosis.

Conclusions:

Our results of this meta-analysis demonstrate that high SBF2-AS1 expression may become a potential target for predicting the prognosis of human cancers.

Novel Regulatory Factors and Small-Molecule Inhibitors of FGFR4 in Cancer

Fibroblast growth factor receptor 4 (FGFR4) is a tyrosine kinase receptor that is a member of the fibroblast growth factor receptor family and is stimulated by highly regulated ligand binding. Excessive expression of the receptor and its ligand, especially FGF19, occurs in many types of cancer. Abnormal FGFR4 production explains these cancer formations, and therefore, this receptor has emerged as a potential target for inhibiting cancer development. This review discusses the diverse mechanisms of oncogenic activation of FGFR4 and highlights some currently available inhibitors targeting FGFR4.

Long Non-Coding RNA KCNQ1OT1 Promotes Progression of Hepatocellular Carcinoma by miR-148a-3p/IGF1R Axis

Accumulating evidence have suggested that long non-coding RNAs (lncRNAs) act as a critical regulator in tumorgenesis. LncRNA KCNQ1OT1 (KCNQ1OT1) has been recently shown to be dysregulated in many cancers. This study was aimed to explore the biological role of KCNQ1OT1 in hepatocellular carcinoma (HCC). In our study, we first observed the expression level of KCNQ1OT1 was distinctly up-regulated in HCC tissues and cell lines compared with adjacent non-cancer tissues and normal liver cell line. And clinical results indicated that higher expression of KCNQ1OT1 was correlated with poor prognosis of patients with HCC. Next, functional studies revealed that knockdown of KCNQ1OT1 induced apoptosis and repressed proliferation, migration and invasion of HCC cells. In addition, knockdown of KCNQ1OT1 suppressed xenograft tumor growth in vivo. Mechanically, we found that KCNQ1OT1 can promote the expression of IGF1R by functioning as a competing endogenous RNA of miR-148a-3p. In conclusion, our results shown the oncogenic role of KCNQ1OT1 in HCC by regulating the miR-148a-3p/IGF1R axis and may provide a new insight and a potential therapeutic target for HCC.

lncRNA HAND2-AS1 Inhibits Liver Cancer Cell Proliferation and Migration by Upregulating SOCS5 to Inactivate the JAK-STAT Pathway

Objective: lncRNA HAND2 antisense RNA 1 (HAND2-AS1) is consistently well recognized to suppress multiple tumors, while its function was uncertified in liver cancer. Materials and Methods: qRT-PCR analysis and TCGA database discovered the expression in liver cancer. CCK-8 and Transwell migration assay demonstrated the impact of HAND2-AS1 on cell proliferation and migration. Bioinformatic analysis and luciferase reporter assay were utilized to monitor the binding between HAND2-AS1 or SOCS5 mRNA and miR-3118. The function of SOCS5 on inactivating the JAK-STAT pathway was confirmed through Western blot assays. Rescue experiments unmasked that HAND2-AS1-mediated SOCS5 affected cell proliferation and migration through the JAK-STAT pathway in liver cancer. Results: The authors discovered the downregulated HAND2-AS1 in liver cancer cells. HAND2-AS1 augmentation apparently impaired the capacity of liver cancer viability, proliferation, and migration. Cytoplasmic HAND2-AS1 directly bound to miR-3118 and released SOCS5, leading to upregulation of SOCS5. Next, the negative regulator role of SOCS5 in the adjusting JAK-STAT pathway was reconfirmed in this study. Conclusions: HAND2-AS1 enhanced inactivation of the JAK-STAT pathway through sponging miR-3118 and facilitating SOCS5 to retard cell proliferation and migration in liver cancer.

LncRNA SNHG16 as a potential biomarker and therapeutic target in human cancers

Long non-coding RNAs (lncRNAs) represent an important class of RNAs comprising more than 200 nucleotides, which are produced by RNA polymerase II. Although lacking an open reading framework and protein-encoding activity, lncRNAs can mediate endogenous gene expression by serving as chromatin remodeler, transcriptional or post-transcriptional modulator, and splicing regulator during gene modification. In recent years, increasing evidence shows the significance of lncRNAs in many malignancies, with vital roles in tumorigenesis and cancer progression. Moreover, lncRNAs were also considered potential diagnostic and prognostic markers in cancer. The lncRNA small nuclear RNA host gene 16 (SNHG16), found on chromosome 17q25.1, represents a novel tumor-associated lncRNA. SNHG16 was recently found to exhibit dysregulated expression in a variety of malignancies. There are growing evidence of SNHG16's involvement in characteristics of cancer, including proliferation, apoptosis, together with its involvement in chemoresistance. In addition, SNHG16 has been described as a promising diagnostic and prognostic biomarker in cancer patients. The current review briefly summarizes recently reported findings about SNHG16 and discuss its expression, roles, mechanisms, and diagnostic and prognostic values in human cancers.

SNHG16/miR-605-3p/TRAF6/NF-κB feedback loop regulates hepatocellular carcinoma metastasis

The mechanism by which miR‐605‐3p regulates hepatocellular carcinoma (HCC) metastasis has not been clarified. In this study, we found that miR‐605‐3p was down‐regulated in HCC and that low miR‐605‐3p expression was associated with tumour thrombus and tumour satellites. HCC patients with low miR‐605‐3p expression showed shorter overall survival and disease‐free survival after surgery. Overexpression of miR‐605‐3p inhibited epithelial‐mesenchymal transition and metastasis of HCC through NF‐κB signalling by directly inhibiting expression of TRAF6, while silencing of miR‐605‐3p had the opposite effect. We also found that SNHG16 directly bound to miR‐605‐3p as a competing endogenous RNA. Mechanistically, high expression of SNHG16 promoted binding to miR‐605‐3p and inhibited its activity, which led to up‐regulation of TRAF6 and sustained activation of the NF‐κB pathway, which in turn promoted epithelial‐mesenchymal transition and metastasis of HCC. TRAF6 increased SNHG16 promoter activity by activating NF‐κB, thereby promoting the transcriptional expression of SNHG16 and forming a positive feedback loop that aggravated HCC malignancy. Our findings reveal a mechanism for the sustained activation of the SNHG16/miR‐605‐3p/TRAF6/NF‐κB feedback loop in HCC and provide a potential target for a new HCC treatment strategy.

A Key mRNA-miRNA-lncRNA Competing Endogenous RNA Triple Sub-network Linked to Diagnosis and Prognosis of Hepatocellular Carcinoma

Growing evidence has illustrated critical roles of competing endogenous RNA (ceRNA) regulatory network in human cancers including hepatocellular carcinoma. In this study, we aimed to find promising diagnostic and prognostic biomarkers for patients with hepatocellular carcinoma. Three novel unfavorable prognosis-associated genes (CELSR3, GPSM2, and CHEK1) was first identified. We also demonstrated that these genes were significantly upregulated in hepatocellular carcinoma cell lines and tissues. Next, 154 potential miRNAs of CELSR3, GPSM2, and CHEK1 were predicted. CHEK1-hsa-mir-195-5p/hsa-mir-497-5p and GPSM2-hsa-mir-122-5p axes were defined as two key pathways in carcinogenesis of hepatocellular carcinoma by combination of in silico analysis and experimental validation. Subsequently, lncRNAs binding to hsa-mir-195-5p, hsa-mir-497-5p, and hsa-mir-122-5p were predicted via starBase and miRNet databases. After performing expression analysis and survival analysis for these predicted lncRNAs, we showed that nine lncRNAs (SNHG1, SNHG12, LINC00511, HCG18, FGD5-AS1, CERS6-AS1, NUTM2A-AS1, SNHG16, and ASB16-AS1) were markedly increased in hepatocellular carcinoma and their upregulation indicated poor prognosis. Moreover, a similar mRNA-miRNA-lncRNA analysis for six “known” genes (CLEC3B, DNASE1L3, PTTG1, KIF2C, XPO5, and UBE2S) was performed. Subsequently, a comprehensive mRNA-miRNA-lncRNA triple ceRNA network linked to prognosis of patients with hepatocellular carcinoma was established. Moreover, all RNAs in this network exhibited significantly diagnostic values for patients with hepatocellular carcinoma. In summary, the current study constructed a mRNA-miRNA-lncRNA ceRNA network associated with diagnosis and prognosis of hepatocellular carcinoma.

Can small nucleolar RNA be a novel molecular target for hepatocellular carcinoma?

BACKGROUND

Globally, hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death. Recently, many studies have demonstrated that small nucleolar RNA (snoRNA) was closely related to HCC.

OBJECTIVE

To explore whether snoRNA can be used as a molecular target for HCC.

METHODS

The PubMed, Embase, and Cochrane databases were searched for the published literatures related to snoRNA and HCC until August 12, 2019. After identification, screening, and verification, this study finally included 26 studies correlating small nucleolar RNA host gene (SNHG) and HCC, and 8 studies correlating snoRNA and HCC. Based on the collation of the relevant literature, the correlation network diagram between snoRNAs and HCC was constructed.

RESULTS

The SNHGs, such as SNHG1, SNHG6, SNHG16, and SNHG20 can play varied roles in HCC through different regulatory mechanisms. These SNHGs can promote and inhibit tumorigenesis. SNORD76 can promote the proliferation of tumor tissues and cells in vitro through different pathways. SnoU2_19 and SNORD76 can function through the same pathway. SNHG3, SNHG20, SNHG6, SNORD76, and snoRA47 can modulate epithelial-mesenchymal transition (EMT) to regulate the development of HCC cell or tissue. SNHG16, SNORD76, and SnoU2_19 can regulate the development of HCC through Wnt/β-catenin signaling pathway.

CONCLUSION

snoRNA can regulate the occurrence of HCC by modulating multiple molecular signaling pathways. Hence, snoRNA can be a potential molecular target for HCC.

LncRNA SBF2-AS1 affects the radiosensitivity of non-small cell lung cancer via modulating microRNA-302a/MBNL3 axis

Background: Long non-coding RNAs (lncRNAs) have been reported to participate in many diseases including non-small cell lung cancer (NSCLC), thus our objective was to investigate the impact of lncRNA SBF2-AS1 modulating microRNA-302a (miR-302a) expression on radiosensitivity of NSCLC.Methods: The expression of SBF2-AS1, miR-302a and muscleblind-like 3 (MBNL3) in NSCLC tissues of the radiotherapy-sensitive and radiotherapy-resistant groups was tested. The radiosensitivity of parent and resistant strains (NCI-H1299 and NCI-H1299_R cells) was detected. Further, cells were treated with si-SBF2-AS1 and miR-302a mimics to determine their roles in proliferation and apoptosis of parent strain and resistant strain cells as well as transfected cells. The in-vivo growth capacity of the cells and the effect of radiotherapy on tumor size of NSCLC were detected.Results: Up-regulated SBF2-AS1 and MBNL3 and down-regulated miR-302a in NSCLC tissues of the radiotherapy resistant group. Overexpression of SBF2-AS1 and MBNL3 and low expression of miR-302a were witnessed in NCI-H1299_R cells. Down-regulated SBF2-AS1 or up-regulated miR-302a suppressed the proliferation while boosted the apoptosis of NCI-H1299 cells and decreased the radioresistance of the NCI-H1299_R cells. Silencing SBF2-AS1 or up-regulating miR-302a restrained tumor growth in vivo.Conclusion: Our study presents that high expression of miR-302a or inhibition of SBF2-AS1 can enhance the radiosensitivity and apoptosis of NSCLC cells through downregulation of MBNL3, which is a therapeutic target for NSCLC.

SNHG16: A Novel Long-Non Coding RNA in Human Cancers

Long noncoding RNAs (lncRNAs) have recently been considered as central regulators in diverse biological processes controlling tumorigenesis. Small nucleolar RNA host gene 16 (SNHG16) is an important tumor-associated lncRNA mainly involved in tumorigenesis and progression by competing with endogenous RNA (ceRNA) which sponges tumor-suppressive microRNA (miRNA), and by its recruitment mechanism. SNHG16 is overexpressed in tumor tissues and cell lines of different kinds of cancers, and its presence is associated with a poor clinical prognosis. Reviewing all publications about SNHG16 revealed that it plays a key role in the different hallmarks that define human cancer, including promoting proliferation, activating migration and invasion, inhibiting apoptosis, affecting lipid metabolism and chemoresistance. This review highlights the role that the aberrant expression of SNHG16 plays in the development and progression of cancer, and suggests that SNHG16 may function as a potential biomarker and therapeutic target for human cancers.

Role of SNHG16 in human cancer

A growing body of evidence suggests that long non-coding RNAs (lncRNAs), a novel class of non-coding endogenous single-stranded RNA, play a key role in multiple physiological and pathological processes through transcriptional interference, post-transcriptional regulation, and epigenetic modification. Furthermore, many studies have shown that lncRNAs-as oncogenes or tumour suppressors-play an important role in the occurrence and development of human cancers. Small nucleolar RNA host gene 16 (SNHG16) was initially identified as an oncogenic lncRNA in neuroblastoma, and has since been identified as a carcinogenic regulator of various malignant tumours. Overexpression of SNHG16 is associated with clinical and pathological characteristics of cancer patients, and regulates cell proliferation, apoptosis, invasion and metastasis through a variety of potential mechanisms. Therefore, SNHG16 may be a promising biomarker and therapeutic target for cancers. In this review, we summarize the biological function, related mechanisms and potential clinical significance of SNHG16 in multiple human cancers.

Mechanisms and Functions of Long Non-Coding RNAs at Multiple Regulatory Levels

Long non-coding (lnc) RNAs are non-coding RNAs longer than 200 nt. lncRNAs primarily interact with mRNA, DNA, protein, and miRNA and consequently regulate gene expression at the epigenetic, transcriptional, post-transcriptional, translational, and post-translational levels in a variety of ways. They play important roles in biological processes such as chromatin remodeling, transcriptional activation, transcriptional interference, RNA processing, and mRNA translation. lncRNAs have important functions in plant growth and development; biotic and abiotic stress responses; and in regulation of cell differentiation, the cell cycle, and the occurrence of many diseases in humans and animals. In this review, we summarize the functions and mechanisms of lncRNAs in plants, humans, and animals at different regulatory levels.

SNHG16 as the miRNA let-7b-5p sponge facilitates the G2/M and epithelial-mesenchymal transition by regulating CDC25B and HMGA2 expression in hepatocellular carcinoma

Long noncoding RNAs (lncRNAs) play crucial roles in hepatocellular carcinoma (HCC). However, the underlying molecular mechanisms of small nucleolar RNA host gene 16 (SNHG16) for regulating the cell cycle and epithelial to mesenchymal transition (EMT) remain elusive. In this study, SNHG16 expression profiles of HCC tissues or cell lines were compared with those of normal tissues or hepatocyte cell line. The effect of SNHG16 knockdown in HCC cell lines was investigated by using in vitro loss-of-function experiments and in vivo nude mouse experiments. The potential molecular regulatory mechanism of SNHG16 in HCC progression was investigated by using mechanistic experiments and rescue assays. The results revealed that SNHG16 was highly expressed in HCC tissues and cell lines, which predicted poor prognosis of HCC patients. On one hand, the downregulation of SNHG16 induced G2/M cell cycle arrest, inducing cell apoptosis and suppression of cell proliferation. On the other hand, it inhibited cell metastasis and EMT progression demonstrated by in vitro loss-of-function cell experiments. Besides, knockdown of SNHG16 increased the sensitivity of HCC cells to cisplatin. For the detailed mechanism, SNHG16 was demonstrated to act as a let-7b-5p sponge in HCC. SNHG16 facilitated the G2/M cell cycle transition by directly acting on the let-7b-5p/CDC25B/CDK1 axis, and promoted cell metastasis and EMT progression by regulating the let-7b-5p/HMGA2 axis in HCC. In addition, the mechanism of SNHG16 for regulating HCC cell proliferation and metastasis was further confirmed in vivo by mouse experiments. Furthermore, these results can provide new insights into HCC treatment and its molecular pathogenesis, which may enlighten the further research of the molecular pathogenesis of HCC.

Long non-coding RNA SNHG16 regulates human aortic smooth muscle cell proliferation and migration via sponging miR-205 and modulating Smad2

The present study investigated the role of long non‐coding RNA (lncRNA) small nucleolar RNA host gene 16 (SNHG16) in the human aortic smooth muscle cell (HASMC) proliferation and migration and explored the potential link between SNHG16 and atherosclerosis. Our results showed that platelet‐derived growth factor (PDGF)‐bb treatment promoted cell proliferation and migration with concurrent up‐regulation of SNHG16 in HASMCs. Small nucleolar RNA host gene 16 overexpression promoted HASMC proliferation and migration, while SNHG16 knockdown suppressed cell proliferation and migration in PDGF‐bb‐stimulated HASMCs. The bioinformatic analyses showed that SNHG16 possessed the complementary binding sequence with miR‐205, where the interaction was confirmed by luciferase reporter assay and RNA pull‐down assay in HASMCs, and SNHG16 inversely regulated miR‐205 expression. MiR‐205 overexpression attenuated the enhanced effects of PDGF‐bb treatment on HASMC proliferation and migration. Moreover, Smad2 was targeted and inversely regulated by miR‐205, while being positively regulated by SNHG16 in HASMCs. Smad2 knockdown attenuated PDGF‐bb‐mediated actions on HASMC proliferation and migration. Both miR‐205 overexpression and Smad2 knockdown partially reversed the effects of SNHG16 overexpression on HASMC proliferation and migration. Moreover, SNHG16 and Smad2 mRNA were up‐regulated, while miR‐205 was down‐regulated in the plasma from patients with atherosclerosis. Small nucleolar RNA host gene 16 expression was inversely correlated with miR‐205 expression and positively correlated with Smad2 expression in the plasma from atherosclerotic patients. In conclusion, our data showed the up‐regulation of SNHG16 in pathogenic‐stimulated HASMCs and clinical samples from atherosclerotic patients. Small nucleolar RNA host gene 16 regulated HASMC proliferation and migration possibly via regulating Smad2 expression by acting as a competing endogenous RNA for miR‐205.

Long intergenic noncoding RNA SNHG16 interacts with miR-195 to promote proliferation, invasion and tumorigenesis in hepatocellular carcinoma

Long non-coding RNAs (lncRNAs) have been confirmed crucial regulators in tumorgenesis. Small nucleolar RNA host gene 16 (SNHG16) has been recently shown to be dysregulated, which uncovered to be a potential oncogene in some cancers. However, the biological function and potential mechanism of SNHG16 in hepatocellular carcinoma (HCC) remain unclear. In our study, our observations showed that the expression level of SNHG16 in HCC tissues and cell lines was upregulated compared with adjacent noncancerous tissues and normal cells. In vitro, loss-of-function experiments revealed that SNHG16 knockdown suppressed the proliferation and weakened invasion of SMMC7721 and HepG2 cells. miR-195 expression was significantly decreased in HCC tissues and negatively correlated with SNHG16 expression. Furthermore, RIP and dual luciferase reporter assays showed that SNHG16 acted as an endogenous sponge by directly binding to miR-195 and downregulated its expression. SNHG16 overexpression inverted the inhibitory effect of miR-195 on proliferation and invasion of SMMC7721 and HepG2 cells. Additionally, SNHG16 depletion resulted in lower tumor growth and weight loss, in vivo. In conclusion, our findings reported that the oncogenic role of SNHG16 in HCC tumorigenesis through a novel SNHG16-miR-195 axis, which provided a novel insight for HCC and helped to probe a potential therapeutic target for the deadly disease.

The lncRNA SNHG16 affects prognosis in hepatocellular carcinoma by regulating p62 expression

Long noncoding RNAs (lncRNAs) regulate tumor development and progression by promoting proliferation, invasion, and metastasis. The oncogenic role of lncRNA SNHG16 in hepatocellular carcinoma (HCC) has not been revealed. LncRNA SNHG16 is upregulated in HCC and correlates with poorer prognosis. Patients with high SNHG16 expression showed lower rates of overall and disease-free survival than patients with low SNHG16 expression. Multivariate Cox regression revealed that SNHG16 expression was an independent predictor of poor overall and disease-free survival. In vitro, SNHG16 promoted HCC cell proliferation, migration, and invasion while inhibiting apoptosis; in vivo, it accelerated tumor development. Altering SNHG16 expression altered levels of miR-17-5p, which in turn modified expression of p62, which has been shown to regulate the mTOR and NF-κB pathways. Indeed, altering SNHG16 expression in HCC cells activated mTOR and NF-κB signaling. These results reveal a potential mechanism for the oncogenic role of SNHG16 in HCC. SNHG16 may therefore be a promising diagnostic marker as well as therapeutic target in HCC.

Long noncoding RNA SNHG16 promotes human retinoblastoma progression via sponging miR-140-5p

Small nucleolar RNA host gene 16 (SNHG16), a long non-coding RNA, was reported to function as an oncogene in multiple cancers. However, its biological function and regulatory mechanism in retinoblastoma (RB) has not yet been revealed. In this study, we attempted to ascertain the biological role and underlying regulatory mechanism of SNHG16 in RB progression. The expression levels of SNHG16 were measured in RB tissues and cell lines. The effects of SNHG16 knockdown on the proliferation, colony formation, cell cycle progression and apoptosis were investigated using corresponding experiments. Bioinformatic analysis, luciferase reporter assay, and RNA immunoprecipitation assay were applied to identify potential microRNAs (miRs) that could bind with SNHG16. A nude model was established to investigate the effect of SNHG16 knockdown on tumor growth in vivo. We found that SNHG16 expression was upregulated in RB tissues and cell lines compared with normal controls. Knockdown of SNHG16 in RB cells significantly inhibited the proliferation and colony formation, and promoted apoptosis in vitro, as well as retarded tumor growth in vivo. Mechanistic investigation illustrated that SNHG16 acted as a sponge for miR-140-5p and regulated its expression in RB cells. Clinical evidence revealed a negative correlation between SNHG16 and miR-140-5p in RB specimens. Rescue experiments showed that inhibition of miR-140-5p partially attenuated the growth-suppressing effects of SNHG16-depletion on RB cells.. Collectively, SNHG16 exerts oncogenic role in RB by sponging miR-140-5p, suggesting that SNHG16 might be a potential therapy target for RB.