Role of SNHG7-miR-653-5p-STAT2 feedback loop in regulating neuroblastoma progression

Role of non-coding RNAs in neuroblastoma

Neuroblastoma is known as the most prevalent extracranial malignancy in childhood with a neural crest origin. It has been widely accepted that non-coding RNAs (ncRNAs) play important roles in many types of cancer, including glioma and gastrointestinal cancers. They may regulate the cancer gene network. According to recent sequencing and profiling studies, ncRNAs genes are deregulated in human cancers via deletion, amplification, abnormal epigenetic, or transcriptional regulation. Disturbances in the expression of ncRNAs may act either as oncogenes or as anti-tumor suppressor genes, and can lead to the induction of cancer hallmarks. ncRNAs can be secreted from tumor cells inside exosomes, where they can be transferred to other cells to affect their function. However, these topics still need more study to clarify their exact roles, so the present review addresses different roles and functions of ncRNAs in neuroblastoma.

LncRNA AFAP1-AS1 Induces Gefitinib Resistance of Lung Adenocarcinoma Through the miR-653-5p/AGR2 Axis

Purpose

Gefitinib resistance limits the therapeutic efficacy of gefitinib to lung adenocarcinoma (LUAD). The goal of this research is to learn more about the lncRNA AFAP1-AS1 and how it functions in gefitinib-resistant LUAD cells.

Methods

RT-qPCR was performed to test the expression of AFAP1-AS1, miR-653-5p and AGR2 in LUAD tissues with acquired resistance to gefitinib or not as well as in gefitinib-resistant LUAD cells. Cell proliferation, invasion and apoptosis were measured by CCK8 assays, transwell invasion assays and flow cytometry, respectively. Luciferase reporter assay showed that miR-653-5p and AFAP1-AS1 or AGR2 interactions.

Results

In gefitinib-resistant LUAD cells and tissues, AFAP1-AS1 was overexpressed. Meanwhile, silencing AFAP1-AS1 reduced proliferation and migration while increasing apoptosis and gefitinib sensitivity. Mechanically, AFAP1-AS1 sequestered the miR-653-5p and blocked the inhibition of miR-653-5p to AGR2 and stepwise upregulated AGR2 overexpression in LUAD gefitinib resistant cells, resulting gefitinib resistance in LUAD.

Conclusion

AFAP1-AS1 promotes gefitinib-resistance LUAD cells through a previously unrecognized miR-653-5p/AGR2 axis, suggesting targeting AFAP1-AS1/miR-653-5p/AGR2 axis might be a promising way for LUAD intervention.

Roles of lncRNAs in childhood cancer: Current landscape and future perspectives

According to World Health Organization (WHO), cancer is the leading cause of death for children and adolescents. Leukemias, brain cancers, lymphomas and solid tumors, such as neuroblastoma, ostesarcoma and Wilms tumors are the most common types of childhood cancers. Approximately 400,000 children and adolescents between the ages of 0 and 19 are diagnosed with cancer each year worldwide. The cancer incidence rates have been rising for the past few decades. Generally, the prognosis of childhood cancers is favorable, but the survival rate for many unresectable or recurring cancers is substantially worse. Although random genetic mutations, persistent infections, and environmental factors may serve as contributing factors for many pediatric malignancies, the underlying mechanisms are yet unknown. Long non-coding RNAs (lncRNAs) are a group of transcripts with longer than 200 nucleotides that lack the coding capacity. However, increasing evidence indicates that lncRNAs play vital regulatory roles in cancer initiation and development in both adults and children. In particular, many lncRNAs are stable in cancer patients' body fluids such as blood and urine, suggesting that they could be used as novel biomarkers. In support of this notion, lncRNAs have been identified in liquid biopsy samples from pediatric cancer patients. In this review, we look at the regulatory functions and underlying processes of lncRNAs in the initiation and progression of children cancer and discuss the potential of lncRNAs as biomarkers for early detection. We hope that this article will help researchers explore lncRNA functions and clinical applications in pediatric cancers.

Mesenchymal stem cells-derived exosomal miR-653-5p suppresses laryngeal papilloma progression by inhibiting BZW2

OBJECTIVES

Although miR-653-5p has been validated to participate in the progression of multiple types of cancer, the functional role of exosomal miR-653-5p derived from Mesenchymal Stem Cells (MSCs) in Laryngeal Papilloma (LP) has still remained elusive. Hence, this study aimed to investigate the role of MSCs-derived exosomal miR-653-5p in LP.

METHODS

LP tissues (n = 15) and adjacent normal tissues (n = 10) were collected to examine the expression level of miR-653-5p. The expression level of miR-653-5p in LP cells and normal cells was also detected. Then, miR-653-5p was overexpressed or silenced to explore its effects on the proliferation, migration, invasion, and apoptosis of LP cells. Thereafter, the effects of exosomal miR-653-5p derived from MSCs on LP cell progression and the potential regulatory mechanism of miR-653-5p were assessed.

RESULTS

It was revealed that the expression level of miR-653-5p was downregulated in LP tissues and cells. In addition, miR-653-5p suppressed the proliferation, migration, invasion, and apoptosis of LP cells. Exosomes derived from MSCs played a suppressive role in LP development and mediated the transmission of miR-653-5p to LP cells. Further exploration identified Basic leucine Zipper and W2 domains 2 (BZW2) as the target of miR-653-5p. More importantly, the rescue experiments revealed that MSCs-secreted exosomal miR-653-5p efficiently inhibited the aggressive phenotypes of LP cells, which could be significantly reversed by BZW2 overexpression in LP cells.

CONCLUSION

MSCs-derived exosomal miR-653-5p exerted inhibitory effects on LP progression through targeting BZW2, which provided a novel idea for the therapy of LP.

CLINICAL TRIAL REGISTRATION NUMBER

chictr-ior-17011021.

The emerging role of miR-653 in human cancer

MicroRNAs (miRNAs) refer to a family of non-coding RNA with ~22 nucleotides in length. A high number of studies show evidence that deregulation in miRNAs expression could be implicated in the processes of many pathologies such as cancer, hypoxia, and stroke. Herein, we aimed to summarize the miR-653 expression level and molecular mechanisms through which it functions in human cancer. It was found that variations in miR-653 expression are linked to tumor aggressiveness and unfavorable prognosis in human cancer, and it plays an inhibitory effect in some types of cancer, such as breast, cervical, liver, renal, and lung cancers. In contrast, it plays an acceleratory impact in some other cancers, such as bladder and prostate cancers. In gastric cancer, the role played by miR-653 is still controversial and will need to be elucidated in future studies. Future studies could definitely establish targeting miR-653 as a novel strategy in human cancer, from diagnosis to effective treatment.

The role of ncRNAs in neuroblastoma: mechanisms, biomarkers and therapeutic targets

Neuroblastoma (NB) is a malignant tumor in young children that originates from the neural crest of the sympathetic nervous system. Generally, NB occurs in the adrenal glands, but it can also affect the nerve tissues of the neck, chest, abdomen, and pelvis. Understanding the pathophysiology of NB and developing novel therapeutic approaches are critical. Noncoding RNAs (ncRNAs) are associated with crucial aspects of pathology, metastasis and drug resistance in NB. Here, we summarized the pretranscriptional, transcriptional and posttranscriptional regulatory mechanisms of ncRNAs involved in NB, especially focusing on regulatory pathways. Furthermore, ncRNAs with the potential to serve as biomarkers for risk stratification, drug resistance and therapeutic targets are also discussed, highlighting the clinical application of ncRNAs in NB.

LncRNA SNHG7 Promotes the HCC Progression Through miR-122-5p/FOXK2 Axis

Hepatocellular carcinoma (HCC) is a malignant tumor with high mortality and severe complication in China. Numerous studies have shown that long noncoding RNAs (lncRNAs) are involved in the regulation of various processes in cancer cells. Our research aimed to investigate the underlying mechanism of the lncRNA small nucleolar RNA host gene 7 (SNHG7) in HCC development. The expression of SNHG7, microRNA-122-5p (miR-122-5p), and Forkhead box K2 (FOXK2) was assessed via quantitative real-time polymerase chain reaction. 3-(4,5) -dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) and transwell assays were performed to measure cell viability, migration, and invasion, respectively. The relative protein levels were detected by Western blot. The relationships between miR-122-5p and SNHG7 or FOXK2 were predicted by online software and then confirmed by dual-luciferase reporter assay. Animal experiments were conducted to clarify the effects of SNHG7 on proliferation in vivo. To begin with, SNHG7 was upregulated, while miR-122-5p was downregulated in HCC tissues and cells. Downregulation of SNHG7 inhibited cell growth and metastasis. Interestingly, SNHG7 could abolish the effects of miR-122-5p on HCC cells. Furthermore, miR-122-5p targeted FOXK2 and miR-122-5p recovered the effects of FOXK2 downregulation on cell growth and metastasis in HCC cells. Besides, SNHG7 facilitated HCC tumor growth in vivo through the miR-122-5p/FOXK2 axis. The lncRNA SNHG7 boosted the development of HCC by regulating FOXK2 through sponging miR-122-5p.

Long non-coding RNA PRNCR1 promotes ovarian cancer cell proliferation, migration and invasion by targeting the miR-653-5p/ELF2 axis

Recent studies have shown that prostate cancer-associated long non-coding RNA, PRNCR1, plays crucial roles in the development of multiple human cancers. However, its role in ovarian cancer is barely known. This study was carried out to investigate the role of PRNCR1 and the underlying mechanisms in OC. The expression of PRNCR1 and miR-653-5p in OC cell lines and tissues were detected by qRT-PCR. The expression of ELF2 protein was evaluated by Western blot analysis. Cell proliferation was measured by colony formation and MTT assay. Cell invasion and migration were evaluated by Transwell and wound healing assay. Luciferase reporter assay and RNA-binding protein immunoprecipitation assay were performed to determine the interaction between miR-653-5p and PRNCR1, as well as between miR-653-5p and ELF2. In vivo tumor xenograft model was established to evaluate the role of PRNCR1 in tumor growth. Our results demonstrated that PRNCR1 was significantly upregulated in both OC cell lines and tissues, and high expression of PRNCR1 was correlated with poor survival of OC patients. Overexpression of PRNCR1 accelerated OC cell invasion, migration and proliferation. Besides, the expression of PRNCR1 was negatively correlated with the expression of miR-653-5p, while positively correlated with the expression of E74-like factor 2 in OC tissues. Importantly, ELF2 could target miR-653-5p, and PRNCR1 increased the expression levels of ELF2 by sponging miR-653-5p in OC cells. Furthermore, the miR-145-5p/ELF2 axis was involved in the regulation of PRNCR1 in OC progression in vivo. PRNCR1 promotes OC tumor progress via the miR-653-5p/ELF2 axis and might be a potential therapeutic target for OC.

Oncogenic Roles of Small Nucleolar RNA Host Gene 7 (SNHG7) Long Noncoding RNA in Human Cancers and Potentials

Long noncoding RNAs (lncRNAs) are a class of noncoding transcripts characterized with more than 200 nucleotides of length. Unlike their names, some short open reading frames are recognized for them encoding small proteins. LncRNAs are found to play regulatory roles in essential cellular processes such as cell growth and apoptosis. Therefore, an increasing number of lncRNAs are identified with dysregulation in a wide variety of human cancers. SNHG7 is an lncRNA with upregulation in cancer cells and tissues. It is frequently reported with potency of promoting malignant cell behaviors in vitro and in vivo. Like oncogenic/tumor suppressor lncRNAs, SNHG7 is found to exert its tumorigenic functions through interaction with other biological substances. These include sponging target miRNAs (various numbers are identified), regulation of several signaling pathways, transcription factors, and effector proteins. Importantly, clinical studies demonstrate association between high SNHG7 expression and clinicopathological features in cancerous patients, worse prognosis, and enhanced chemoresistance. In this review, we summarize recent studies in three eras of cell, animal, and human experiments to bold the prognostic, diagnostic, and therapeutic potentials.

Prenatal Cadmium Exposure Alters Proliferation in Mouse CD4+ T Cells via LncRNA Snhg7

Objective

Prenatal cadmium (Cd) exposure leads to immunotoxic phenotypes in the offspring affecting coding and non-coding genes. Recent studies have shown that long non-coding RNAs (lncRNAs) are integral to T cell regulation. Here, we investigated the role of long non-coding RNA small nucleolar RNA host gene 7 (lncSnhg7) in T cell proliferation.

Methods

RNA sequencing was used to analyze the expression of lncRNAs in splenic CD4+ T cells with and without CD3/CD28 stimulation. Next, T cells isolated from offspring exposed to control or Cd water throughout mating and gestation were analyzed with and without stimulation with anti-CD3/CD28 beads. Quantitative qPCR and western blotting were used to detect RNA and protein levels of specific genes. Overexpression of a miR-34a mimic was achieved using nucleofection. Apoptosis was measured using flow cytometry and luminescence assays. Flow cytometry was also used to measure T cell proliferation in culture. Finally, lncSnhg7 was knocked down in splenic CD4+ T cells with lentivirus to assess its effect on proliferation.

Results

We identified 23 lncRNAs that were differentially expressed in stimulated versus unstimulated T cells, including lncSnhg7. LncSnhg7 and a downstream protein, GALNT7, are upregulated in T cells from offspring exposed to Cd during gestation. Overexpression of miR-34a, a regulator of lncSnhg7 and GALNT7, suppresses GALNT7 protein levels in primary T cells, but not in a mouse T lymphocyte cell line. The T cells isolated from Cd-exposed offspring exhibit increased proliferation after activation in vitro, but Treg suppression and CD4+ T cell apoptosis are not affected by prenatal Cd exposure. Knockdown on lncSnhg7 inhibits proliferation of CD4+ T cells.

Conclusion

Prenatal Cd exposure alters the expression of lncRNAs during T cell activation. The induction of lncSnhg7 is enhanced in splenic T cells from Cd offspring resulting in the upregulation of GALNT7 protein and increased proliferation following activation. miR-34a overexpression decreased GALNT7 expression and knockdown of lncSnhg7 inhibited proliferation suggesting that the lncSnhg7/miR-34a/GALNT7 is an important pathway in primary CD4+ T cells. These data highlight the need to understand the consequences of environmental exposures on lncRNA functions in non-cancerous cells as well as the effects in utero.

Prognostic effect of lncRNA SNHG7 on cancer outcome: a meta and bioinformatic analysis

BACKGROUND

New evidence from clinical and fundamental researches suggests that SNHG7 is involved in the occurrence and development of carcinomas. And the increased levels of SNHG7 are associated with poor prognosis in various kinds of tumors. However, the small sample size was the limitation for the prognostic value of SNHG7 in clinical application. The aim of the present meta-analysis was to conduct a qualitative analysis to explore the prognostic value of SNHG7 in various cancers.

METHODS

Articles related to the SNHG7 as a prognostic biomarker for cancer patients, were comprehensive searched in several electronic databases. The enrolled articles were qualified via the preferred reporting items for systematic reviews and meta-analysis of observational studies in epidemiology checklists. Additionally, an online database based on The Cancer Genome Atlas (TCGA) was further used to validate our results.

RESULTS

We analyzed 2418 cancer patients that met the specified criteria. The present research indicated that an elevated SNHG7 expression level was significantly associated with unfavorable overall survival (OS) (HR = 2.45, 95% CI: 2.12-2.85, p <0.001). Subgroup analysis showed that high expression levels of SNHG7 were also significantly associated with unfavorable OS in digestive system cancer (HR = 2.31, 95% CI: 1.90-2.80, p <0.001) and non-digestive system cancer (HR = 2.67, 95% CI: 2.12-3.37, p <0.001). Additionally, increased SNHG7 expression was found to be associated with tumor stage and progression (III/IV vs. I/II: HR = 1.76, 95% CI: 1.57-1.98, p <0.001). Furthermore, elevated SNHG7 expression significantly predicted lymph node metastasis (LNM) (HR = 1.98, 95% CI: 1.74-2.26, p <0.001) and distant metastasis (DM) (HR = 2.49, 95% CI: 1.88-3.30, p <0.001) respectively. No significant heterogeneity was observed among these studies. SNHG7 was significantly upregulated in four cancers and the elevated expression of SNHG7 predicted shorter OS in four cancers, worse DFS in five malignancies and worse PFI in five carcinomas based on the validation using the GEPIA on-line analysis tool.

CONCLUSIONS

The present analysis suggests that elevated SNHG7 is significantly associated with unfavorable OS, tumor progression, LNM and DM in various carcinomas, and may be served as a promising biomarker to guide therapy for cancer patients.

Is Long Noncoding SNHG7 a Reliable Diagnostic Tool for Metastasis Diagnosis of Cancer: A Meta-Analysis

Background: The small nucleolar RNA host gene 7 (SNHG7) has been suggested as a biomarker of metastatic cancer; however, its reliability is controversial. Therefore, the goal of this study was to conduct a meta-analysis to assess the reliability of SNHG7 as a comprehensive cancer metastasis diagnostic biomarker. Methods: A comprehensive literature search was conducted using PubMed, Cochrane Library, Web of Science, Embase, and China National Knowledge Infrastructure (CNKI) to identify articles which examined the role of SNHG7 in cancers. Random-effects models and fixed-effects models were conducted to estimate the pooled odds ratios (ORs) for the associations of SNHG7 with distant metastases and lymph node metastases. Hierarchical summary receiver operating characteristic (ROC) models were used to estimate the sensitivity and specificity of SNHG7 as a biomarker for cancer metastasis diagnoses. Results: Nineteen studies comprised 1491 patients were included in this meta-analysis. We found that both distant metastasis (OR = 4.19, 95% confidence interval [CI] = 2.93-5.99, I² = 34%) and lymph node metastasis (OR = 3.07, 95% CI = 1.65-5.68, I² = 79.03%) were significantly associated with a higher expression of SNHG7. We also showed a pooled sensitivity and specificity of 74% (95% CI = 66-82) and 57% (95% CI = 53-61) for distant metastasis; as well as 72% (95% CI = 63-80) and 54% (95% CI = 46-63) for lymph node metastasis, respectively. Conclusion: Our findings suggest that SNHG7 is a potential diagnostic biomarker for metastasis of cancer; however, its clinical application requires stronger evidence due to the low sensitivity and specificity. Further larger-scale studies from diverse settings and cancer types will be necessary to reveal novel insights into SNHG7 as a biomarker for cancer metastasis diagnoses.

Exosomal circular RNA hsa_circ_007293 promotes proliferation, migration, invasion, and epithelial-mesenchymal transition of papillary thyroid carcinoma cells through regulation of the microRNA-653-5p/paired box 6 axis

Circular RNAs (circRNAs) or exosomes have been reported to exert key regulatory and/or communication functions in human cancer. Nevertheless, current literature on the effects of exosomal circRNAs on tumor invasion and metastasis in thyroid cancer is incomplete. The role of tumor-derived exosomes in driving in vitro papillary thyroid carcinoma (PTC) progression and metastasis requires further investigation. In our study, Exosomes were harvested from PTC patient serum and PTC cell culture medium. Gene expression analysis in PTC cell lines and exosomes was performed with quantitative reverse-transcription polymerase chain reaction. Transwell, wound healing, Western blot assays, and the cell counting kit-8 were applied for functional analysis. Dual-luciferase reporter assay was used to examine the interaction between hsa_circ_007293 (circ007293), microRNA (miR)-653-5p, and paired box 6 (PAX6). Results showed that circ007293 was enriched in exosomes derived from PTC patient serum and cell culture media. Moreover, circ007293 could enter PTC cells through exosomes, and exosomal circ007293 promoted PTC cell epithelial-mesenchymal transition, invasion, migration, and proliferation. circ007293 knockdown reversed the malignant phenotype of PTC cells in vitro. Additionally, circ007293 could competitively bind with miR-653-5p to regulate PAX6 expression. Notably, miR-653-5p overexpression or PAX6 inhibition suppressed the malignant effects of exosomal circ007293. These results evidenced that exosomal circ007293 induced EMT and augmented the invasive and migratory abilities of PTC cells via the miR-653-5p/PAX6 axis, suggesting that it may serve as a promising biomarker for cancer progression.

Clinicopathological and prognostic value of long noncoding RNA SNHG7 in cancers: a meta-analysis and bioinformatics

The long intergenic non-coding RNA SNHG7 has been reported to be abnormally expressed in many types of cancer, the results remain controversial. In this study, a meta-analysis was performed to evaluate the clinicopathologic and prognostic value of SNHG7 in cancers. Electronic databases of PubMed, Web of Science, Cochrane Library and Embase were used to search relevant studies. A combined hazard ratio (HR) and its corresponding 95% confidence interval (CI) were used to assess the association between SNHG7 expression and prognosis in cancer patients. Pooled odds ratio (OR) and 95% CI were calculated to elaborate the association between SNHG7 expression and clinicopathological features in cancers. Besides, the data from The Cancer Genome Atlas (TCGA) dataset was used to validate the results. In total, eighteen studies compromising 1303 participants were enrolled in this analysis. The pooled results showed increased SNHG7 expression could predict unfavorable overall survival (OS) (HR = 1.75, 95%CI = 1.52–2.02, P = 0.000). Analysis stratified by follow-up time, cancer types, analysis types, sample sizes and cut off further verified the prognostic value of SNHG7. Additionally, elevated SNHG7 expression was correlated with TNM stage (OR: 3.31, 95%CI = 2.29–4.80, P = 0.000), lymph node metastasis (OR = 3.32, 95%CI = 1.61–6.83, P = 0.004), and tumor differentiation (OR = 1.92, 95%CI = 1.22–3.03, P =0.005) in patients with cancers. Excavation of TCGA dataset valuated that SNHG7 was upregulated in some cancers and predicted worse OS, which partially confirmed our results in this meta-analysis.

The Prognostic Value of Long Non-Coding RNA SNHG7 in Human Cancer: A Meta-Analysis

BACKGROUND

The long non-coding RNA SNHG7 is upregulated in many types of cancer and plays a role as an oncogene. However, its overall predictive ability in human cancer prognosis has not been assessed using existing databases. Therefore, further study of its prognostic value and clinical significance in human malignancies is warranted.

METHODS

We systematically collected relevant literature from multiple electronic document databases about the relationship between SNHG7 expression level and prognosis in patients with solid cancers. We further screened them for eligibility. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were used to assess the prognostic value. Odds ratios (ORs) and their 95% CIs were collected to evaluate the relationship between the expression of SNHG7 and clinicopathological features, including lymph node metastasis (LNM), tumour size, tumour node metastasis (TNM) stage and histological grade.

RESULTS

Fourteen original studies involving 971 patients were enrolled strictly following the inclusion and exclusion criteria. The meta-analysis showed that SNHG7 expression was significantly correlated with poor overall survival (HR = 1.93, 95% CI: 1.64-2.26, p<0.001) in human cancer patients. In addition, the pooled OR indicated that overexpression of SNHG7 was associated with earlier LNM (OR = 1.83, 95% CI: 1.44-2.32; P <0.001), and advanced TNM stage (OR = 1.82, 95% CI: 1.44-2.30; P <0.001).Meanwhile, there was no significant heterogeneity between the selected studies, proving the reliability of the meta-analysis results.

CONCLUSIONS

High SNHG7 expression may predict poor oncological outcomes in patients with multiple human cancers, which could be a novel prognostic biomarker of unfulfilled clinicopathological features. However, further high-quality studies are needed to verify and strengthen the clinical value of SNHG7 in different types of cancer.

Advances in pharmacotherapy for neuroblastoma

INTRODUCTION

Neuroblastoma is the most prevalent cancer type diagnosed within the first year after birth and accounts for 15% of deaths from pediatric cancer. Despite the improvements in survival rates of patients with neuroblastoma, the incidence of the disease has increased over the last decade. Neuroblastoma tumor cells harbor a vast range of variable and heterogeneous histochemical and genetic alterations which calls for the need to administer individualized and targeted therapies to induce tumor regression in each patient.

AREAS COVERED

This paper provides reviews the recent clinical trials which used chemotherapeutic and/or targeted agents as either monotherapies or in combination to improve the response rate in patients with neuroblastoma, and especially high-risk neuroblastoma. It also reviews some of the prominent preclinical studies which can provide the rationale for future clinical trials.

EXPERT OPINION

Although some distinguished advances in pharmacotherapy have been made to improve the survival rate and reduce adverse events in patients with neuroblastoma, a more comprehensive understanding of the mechanisms of tumorigenesis, resistance to therapies or relapse, identifying biomarkers of response to each specific drug, and developing predictive preclinical models of the tumor can lead to further breakthroughs in the treatment of neuroblastoma.

MicroRNA-653-5p Promotes Gastric Cancer Proliferation and Metastasis by Targeting the SOCS6-STAT3 Pathway

MicroRNAs (miRNAs) are emerging as significant regulators of the tumorigenesis of gastric cancer (GC), and may be effective biomarkers for diagnosis, prognosis, and therapeutic targeting for GC. In this study, miR-653-5p was found to be significantly upregulated in GC tissues, serum, and cell lines and was strongly associated with poor prognosis in patients with GC. Furthermore, miR-653-5p promoted GC cell proliferation and metastasis in vivo and in vitro. Suppressor of cytokine signaling 6 (SOCS6) was directly targeted by miR-653-5p, and SOCS6 attenuated miR-653-5p-mediated GC cell growth, migration, and invasion. In addition, SOCS6-mediated inactivation of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signaling pathway was also reversed by the administration of miR-653-5p. The findings from this study support a novel regulatory axis between miR-653-5p, SOCS6, and JAK2/STAT3 that may be a target for diagnosis and therapeutic intervention for GC.

LINC00461/miR-4478/E2F1 feedback loop promotes non-small cell lung cancer cell proliferation and migration

Non-small cell lung cancer (NSCLC) is a prevalent subtype of lung cancer, whose mortality is high. Long non-coding RNAs (lncRNAs) have caught rising attentions because of their intricate roles in regulating cancerization and cancer progression. Long intergenic non-protein coding RNA 461 (LINC00461) has recently shown oncogenic potential in several cancers, but the function of LINC00461 in NSCLC remains to be investigated. Our study planned to unveil the regulatory role of LINC00461 in NSCLC. It was validated that LINC00461 was highly expressed in NSCLC tissues and cell lines and exhibited prognostic significance. Furthermore, LINC00461 expression in advanced stage was much higher than in early stage. Loss-of-function experiments suggested that LINC00461 knockdown impaired cell proliferation, migration, and epithelial-to-mesenchymal transition (EMT). Subcellular fractionation revealed the predominant location of LINC00461 in cytoplasm. Mechanistically, LINC00461 up-regulated E2F transcription factor 1 (E2F1) expression through sponging miR-4478. Besides, E2F1 bound to the promoter of LINC00461 to induce its transcription. Finally, rescue experiments verified that LINC00461 aggravated proliferation, migration, and EMT through targeting miR-4478/E2F1 axis. In consequence, the present study illustrated that LINC00461/miR-4478/E2F1 feedback loop promoted NSCLC cell proliferation and migration, providing a new prognostic marker for NSCLC.

Non-Coding RNAs Participate in the Pathogenesis of Neuroblastoma

Neuroblastoma is one of the utmost frequent neoplasms during the first year of life. This pediatric cancer is believed to be originated during the embryonic life from the neural crest cells. Previous studies have detected several types of chromosomal aberrations in this tumor. More recent studies have emphasized on expression profiling of neuroblastoma samples to identify the dysregulated genes in this type of cancer. Non-coding RNAs are among the mostly dysregulated genes in this type of cancer. Such dysregulation has been associated with a number of chromosomal aberrations that are frequently detected in neuroblastoma. In this study, we explain the role of non-coding transcripts in the malignant transformation in neuroblastoma and their role as biomarkers for this pediatric cancer.

The depletion of Circ-PRKDC enhances autophagy and apoptosis in T-cell acute lymphoblastic leukemia via microRNA-653-5p/Reelin mediation of the PI3K/AKT/mTOR signaling pathway

A range of circular (Circ) RNAs have been demonstrated to be of therapeutic significance for the treatment of acute lymphoblastic leukemia (ALL). Here, we investigated the mechanisms underlying the action of Circ-PRKDC and the microRNA-653-5p/Reelin (miR-653-5p/RELN) axis in T-cell ALL (T-ALL).Clinical specimens were obtained from patients with T-ALL (n = 39) and healthy controls (n = 30). In each specimen, we determined the expression levels of Circ-PRKDC, miR-653-5p, and RELN. Human T-ALL cells (Jurkat) were transfected with Circ-PRKDC- or miR-653-5p-related sequences to investigate cell proliferation, apoptosis, and autophagy. We also determined the levels of Circ-PRKDC, miR-653-5p, RELN, and signaling proteins related to phosphoinositide 3-kinase (PI3K), AKT, and mammalian target of rapamycin (mTOR). Finally, we decoded the interactions between Circ-PRKDC, miR-653-5p, and RELN. The expression levels of Circ-PRKDC and RELN were upregulated in T-ALL tissues and cells while the levels of miR-653-5p were downregulated. Thereafter, then silencing of Circ-PRKDC, or the enforced expression of miR-653-5p, repressed the expression of RELN and the activation of the PI3K/AKT/mTOR signaling pathway, thus enhancing cell autophagy and apoptosis, and disrupting cell proliferation. Circ-PRKDC acted a sponge for miR-653-5p while miR-653-5p targeted RELN. The knockdown of miR-653-5p abrogated the silencing of Circ-PRKDC-induced effects in T-ALL cells. The depletion of Circ-PRKDC elevated miR-653-5p to silence RELN-mediated PI3K/AKT/mTOR signaling activation, thereby enhancing autophagy and apoptosis in T-ALL cells.

STAT1-induced regulation of lncRNA ZFPM2-AS1 predicts poor prognosis and contributes to hepatocellular carcinoma progression via the miR-653/GOLM1 axis

Long noncoding RNAs (lncRNAs) have drawn growing attention owing to their important effects in various tumors, including hepatocellular carcinoma (HCC). Recently, a newly identified lncRNA, ZFPM2 antisense RNA 1 (ZFPM2-AS1), was reported to serve as an oncogene in gastric cancer. However, its function in tumors remains largely unknown. In this study, we identified ZFPM2-AS1 as a novel HCC-related lncRNA, which was observed to be distinctly upregulated in HCC tissues and associated with shorter overall survival. Luciferase reporter and chromatin immunoprecipitation assays suggested that overexpression of ZFPM2-AS1 was induced by STAT1. Functional investigations suggested that the inhibition of ZFPM2-AS1 suppressed cell proliferation, metastasis, cell cycle progression while accelerated cell apoptosis. Mechanistic studies showed that there were two binding sites of miR-653 within the sequence of ZFPM2-AS1 and the levels of ZFPM2-AS1 were negatively correlated with miR-653. In addition, ZFPM2-AS1 could reverse the suppressor effects of miR-653 on the proliferation and metastasis of HCC cells by the modulation of GOLM1, a target gene of miR-653. To conclude, we provided a better understanding of the interaction mechanism between ZFPM2-AS-miR-653-GOLM1 axis, which may help develop prognostic biomarkers and therapeutic target for HCC.

The Role of lncRNAs in Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells

Bone Marrow Mesenchymal Stem Cells (BMSCs) are one of the primary cells found in the bone marrow, and they can differentiate into osteoblasts, chondrocytes, adipocytes and even myoblasts, and are, therefore, considered pluripotent cells. Because of their multipotential differentiation, selfrenewal capability, immunomodulation and other potential activities, BMSCs have become an important source of seed cells for gene therapy, tissue engineering, cell replacement therapy and regenerative medicine. Long non-coding RNA (lncRNA) is an RNA molecule greater than 200 nucleotides in length that is expressed in a variety of species, including animals, plants, yeast, prokaryotes, and viruses, but lacks an apparent open reading frame, and does not have the function of translation into proteins. Many studies have shown that lncRNAs play an important role in the osteogenic differentiation of BMSCs. Here, we describe the role of lncRNAs in the osteogenic differentiation of BMSCs, in order to provide a new theoretical and experimental basis for bone tissue engineering and clinical treatment.

Long noncoding RNA LINC01410 promotes the tumorigenesis of neuroblastoma cells by sponging microRNA-506-3p and modulating WEE1

OBJECTIVE

Neuroblastoma (NBL) is an extra-cranial solid tumor in children. This study was attempted to investigate the regulatory mechanism of long noncoding RNA LINC01410 (LINC01410) on NBL.

METHODS

The expression of LINC01410, miR-506-3p, and WEE1 in NBL was evaluated by quantitative real time polymerase chain reaction. The proliferation and colony formation ability of NBL cells were analyzed by MTT and colony formation assay. Flow cytometry assay was executed to measure the apoptosis and cell cycle. Dual-luciferase reporter assay was used to detect the targeted relationships among LINC01410, miR-506-3p, and WEE1. Additionally, the role of LINC01410 on NBL in vivo was evaluated according to a tumor xenograft model.

RESULTS

The expression of LINC01410 and WEE1 was enhanced and miR-506-3p was inhibited in NBL. LINC01410 knockdown attenuated the cell proliferation, colony formation ability, and inhibited tumor growth. Moreover, LINC01410 silencing facilitated the apoptosis and arrested the cell cycle. LINC01410 interacted with miR-506-3p to elevate the WEE1 expression in NBL. Additionally, miR-506-3p inhibition or WEE1 overexpression weakened the reduction effects of sh-LINC01410 on cell proliferation, colony formation ability, apoptosis, and cell cycle.

CONCLUSIONS

Knockdown of LINC01410 inhibited the development of NBL by miR-506-3p/WEE1 axis in vitro, which could serve as a potential therapeutic target for NBL therapy.

Silencing of long non-coding RNA DLX6-AS1 weakens neuroblastoma progression by the miR-513c-5p/PLK4 axis

Emerging evidence has demonstrated the crucial roles of long noncoding RNAs in human cancers, including neuroblastoma (NB). DLX6 antisense RNA 1 (DLX6-AS1) has been identified as an oncogenic driver in NB. However, the mechanisms of DLX6-AS1 in NB progression are not fully understood. Our data showed that DLX6-AS1 was significantly overexpressed in NB tissues and cells. Moreover, DLX6-AS1 silencing repressed NB cell viability, colony formation, migration, and invasion, and promoted cell cycle arrest and apoptosis in vitro, as well as decreased tumor growth in vivo. Mechanistically, DLX6-AS1 operated as a miR-513c-5p sponge. MiR-513c-5p mediated the regulation of DLX6-AS1 on NB cell malignant progression in vitro. PLK4 was a target of miR-513c-5p- and DLX6-AS1-controlled PLK4 expression via sponging miR-513c-5p. Furthermore, the suppressive effect of miR-513c-5p overexpression on NB cell malignant progression in vitro was reversed by PLK4 upregulation. Our findings identified a novel regulatory mechanism, the DLX6-AS1/miR-513c-5p/PLK4 axis, in NB progression, highlighting a strong rationale for developing DLX6-AS1 as a new target for NB management.

Long Noncoding RNA SNHG7 Accelerates Proliferation, Migration and Invasion of Non-Small Cell Lung Cancer Cells by Suppressing miR-181a-5p Through AKT/mTOR Signaling Pathway

Purpose

Non-small cell lung cancer (NSCLC) is a typical epithelial lung cancer with high metastasis, incidence and mortality. In recent years, long noncoding RNA small nucleolar RNA host gene 7 (SNHG7) has been identified as significant regulator in different cancer types, including NSCLC. However, the underlying molecular mechanism of SNHG7 during NSCLC tumorigenesis and progression remains largely unclear.

Methods

SNHG7 and miR-181a-5p expression in NSCLC tumors and cells were detected by qRT-PCR. Cell viability, migration, invasion and apoptosis were evaluated by CCK-8, transwell and flow cytometry assay, respectively. A549 and NCI-H1299 xenograft mice model was constructed by subcutaneously injecting cells stably transfected with sh-SNHG7 and sh-NC. The interaction between SNHG7 and miR-181a-5p was validated by luciferase reporter system, RIP and RNA pull down assay. Protein expression of cleaved caspase 3, proliferating cell nuclear antigen (PCNA), AKT, p-AKT, mammalian target of rapamycin (mTOR) and p-mTOR was analyzed by Western blot.

Results

SNHG7 expression was up-regulated while miR-181a-5p expression was down-regulated in NSCLC tumors, especially those from patients at Phase III+IV, compared with normal tissues. However, SNHG7 depletion attenuated tumor growth in vitro and in vivo. Moreover, miR-181a-5p inhibitor abolished SNHG7 silencing induced inhibition on proliferation, migration and invasion in NSCLC. Subsequently, we found SNHG7 modulated cell progression by targeting miR-181a-5p and activating AKT/mTOR signaling pathway.

Conclusion

SNHG7 accelerates proliferation, migration and invasion of NSCLC by suppressing miR-181a-5p through AKT/mTOR signaling pathway, thus presenting desirable biomarkers for NSCLC therapy.

Emerging therapeutic targets for neuroblastoma

INTRODUCTION

Neuroblastoma (NB) is the prime cancer of infancy, and accounts for 9% of pediatric cancer deaths. While children diagnosed with clinically stable NB experience a complete cure, those with high-risk disease (HR-NB) do not recover, despite intensive therapeutic strategies. Development of novel and effective targeted therapies is needed to counter disease progression, and to benefit long-term survival of children with HR-NB.

AREAS COVERED

Recent studies (2017-2020) pertinent to NB evolution are selectively reviewed to recognize novel and effective therapeutic targets. The prospective and promising therapeutic targets/strategies for HR-NB are categorized into (a) targeting oncogene-like and/or reinforcing tumor suppressor (TS)-like lncRNAs; (b) targeting oncogene-like microRNAs (miRs) and/or mimicking TS-miRs; (c) targets for immunotherapy; (d) targeting epithelial-to-mesenchymal transition and cancer stem cells; (e) novel and beneficial combination approaches; and (f) repurposing drugs and other strategies in development.

EXPERT OPINION

It is highly unlikely that agents targeting a single candidate or signaling will be beneficial for an HR-NB cure. We must develop efficient drug deliverables for functional targets, which could be integrated and advance clinical therapy. Fittingly, the looming evidence indicated an aggressive evolution of promising novel and integrative targets, development of efficient drugs, and improvised strategies for HR-NB treatment.

LncRNA DLX6-AS1 Promotes the Progression of Neuroblastoma by Activating STAT2 via Targeting miR-506-3p

Background

Neuroblastoma (NB) is a common malignant tumor of the sympathetic nervous system, mainly disturbing children. Long non-coding RNAs (lncRNAs) serving as promising cancer biomarkers have been well recognized. Our study intends to explore the functions of lncRNA X–inactive specific transcript (DLX6-AS1) in NB and provide a potential action mechanism.

Methods

The expression of DLX6-AS1, miR-506-3p and signal transducer and activator of transcription 2 (STAT2) was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and colony formation assay. Cell cycle distribution was determined by flow cytometry assay. The protein level of cell cycle-related markers and STAT2 was detected by Western blot. Glycolysis progress was evaluated according to glucose consumption, lactate production and ATP level. The target genes were predicted by the online database Starbase3.0 and verified by dual-luciferase reporter assay.

Results

DLX6-AS1 expression was highly elevated in NB tissues and cells. DLX6-AS1 deficiency inhibited NB cell proliferation, cell cycle and glycolysis in vitro. MiR-506-3p was a target of DLX6-AS1, and miR-506-3p absence partly reversed the effects of DLX6-AS1 deficiency. Besides, STAT2 was targeted by miR-506-3p, and its expression was regulated by DLX6-AS1 through miR-506-3p. MiR-506-3p restoration also inhibited NB cell malignant behaviors, and STAT2 overexpression partially abolished the role of miR-506-3p restoration. Moreover, DLX6-AS1 deficiency weakened tumor growth in vivo.

Conclusion

DLX6-AS1 regulated cell proliferation, cell cycle and glycolysis in vitro and tumor growth in vivo to promote the development of NB by upregulating STAT2 via targeting miR-506-3p.

Determination of long non-coding RNAs associated with EZH2 in neuroblastoma by RIP-seq, RNA-seq and ChIP-seq

Neuroblastoma (NB) is the most common type of extracranial solid tumor found in children. Despite several treatment options, patients with advanced stage disease have a poor prognosis. Previous studies have reported that enhancer of zeste homolog 2 (EZH2) and long non-coding RNAs (lncRNAs) have abnormal expression levels in NB and participate in tumorigenesis and NB development. However, the association between EZH2 and lncRNAs remain unclear. In the present study, RNA immunoprecipitation-sequencing (RIP-seq) was used to analyze the lncRNAs binding to EZH2. Following EZH2 knockdown via short hairpin RNA, RNA-seq was performed in shEZH2 and control groups in SH-SY5Y cells. Chromatin IP (ChIP)-seq was used to determine the genes that may be regulated by EZH2. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed to identify the signaling pathways involved in NB. The results from RIP-seq identified 94 lncRNAs, including SNHG7, SNHG22, KTN-AS1 and Linc00843. Furthermore, results from RNA-seq demonstrated that, following EZH2 knockdown, 448 genes were up- and 571 genes were downregulated, with 32 lncRNAs up- and 35 downregulated and differentially expressed compared with control groups. Certain lncRNAs, including MALAT1, H19, Linc01021 and SNHG5, were differentially expressed in EZH2-knockdown group compared with the control group. ChIP-seq identified EZH2 located in the promoter region of 138 lncRNAs including CASC16, CASC15, LINC00694 and TBX5-AS1. In summary, the present study demonstrated that certain lncRNAs directly bound EZH2 and regulated EZH2 expression levels. A number of these lncRNAs that are associated with EZH2 may participate in NB tumorigenesis.

[High expression of STAT2 in ovarian cancer and its effect on metastasis of ovarian cancer cells]

OBJECTIVE

To investigate the expression of signal transduction and activator of transcription 2 (STAT2) in ovarian cancer and its correlation with the prognosis of ovarian cancer patients and explore the role of STAT2 inregulating metastasis of ovarian cancer cells.

METHODS

RT-qPCR was performed to detect the expression of STAT2 mRNA in 62 fresh frozen ovarian cancer tissues and 62 normal ovarian tissues; immunohistochemistry was used to detect STAT2 protein expressions in 95 paraffin-embedded ovarian cancer samples and 33 normal ovarian tissues. Kaplan-Meier method was used to analyze the correlation between the expression of STAT2 and the prognosis of the patients. We also examined the relationship between STAT2 and the patients' prognosis by analyzing the data in Kaplan-Meier Plotter database. Western blotting was performed to detect the expression of STAT2 in different ovarian cancer cell lines. In A2780 cells with the highest STAT2 expression, we examined the effects of STAT2 interference on cell migration and invasiveness using Transwell migration assay and on the expressions of the downstream molecule epidermal growth factor receptor (EGFR).

RESULTS

Ovarian cancer tissues expressed significantly higher levels of STAT2 mRNA than normal ovarian tissue. A high STAT2 mRNA expression was correlated with an advanced FIGO stage. Immunohistochemistry showed that 67.4% of the ovarian cancer samples, as compared with 28.3% of normal ovarian tissues, showed high STAT2 expressions. In ovarian cancer patients, a high expression of STAT2 protein was associated with ascites volume, distant metastasis and FIGO stage (P < 0.05). Survival analysis showed that ovarian cancer patients with a high expression of STAT2 protein had poor overall survival (P=0.021) and progression-free survival (P=0.018). STAT2 was overexpressed in all the ovarian cancer cell lines tested, and A2780 cell lines showed the highest expression. Interference of STAT2 significantly suppressed the migration and invasiveness (P < 0.01) and lowered the expression level of EGFR in A2780 cells.

CONCLUSIONS

STAT2 is overexpressed in ovarian cancer. A high expression of STAT2 is associated with a poor prognosis of ovarian cancer patients. STAT2 may promote the metastasis of ovarian cancer by enhancing the expression of EGFR.

Long non-coding RNA SNHG7 promotes neuroblastoma progression through sponging miR-323a-5p and miR-342-5p

Dysregulation of long non-coding RNAs (lncRNAs) has been known to be relevant to the progression of human cancers, including neuroblastoma (NB). Small nucleolar RNA host gene 7 (SNHG7) has been identified as an oncogene in a series of human cancers. The purpose of the present study was to investigate the function and underlying mechanism of SNHG7 in NB progression. qRT-PCR was used to determine the levels of SNHG7, cyclin D1 (CCND1), miR-323a-5p and miR-342-5p. Cell migration and invasion abilities were detected by transwell assays. Glucose consumption and lactate production were assessed using the corresponding assay kits. The targeted interaction between SNHG7 and miR-323a-5p or miR-342-5p was verified by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. Xenograft tumor assays were performed to observe the effect of SNHG7 silencing on tumor growth in vivo. We found that SNHG7 was upregulated in NB tissues and cell lines, and high SNHG7 level was relevant to poor prognosis of NB patients. SNHG7 silencing resulted in the repression of NB cell migration, invasion and glycolysis. SNHG7 directly targeted miR-323a-5p and miR-342-5p and negatively modulated their expression in NB cells. The overexpression of miR-323a-5p or miR-342-5p weakened NB cell migration, invasion and glycolysis. Moreover, miR-323a-5p or miR-342-5p mediated the suppressive effect of SNHG7 silencing on NB cell progression. CCND1 was a direct target of miR-323a-5p and miR-342-5p. Additionally, SNHG7 knockdown repressed tumor growth in vivo. In conclusion, our study suggested that SNHG7 silencing hindered NB progression at least partly though sponging miR-323a-5p and miR-342-5p, illuminating its potential value as a therapeutic target.

Comprehensive analysis of long non‑coding RNA using an associated competitive endogenous RNA network in Wilms tumor

Wilms tumor (WT) is the most common malignant renal neoplasm in children; however, the underlying molecular mechanisms are not well understood. According to the competing endogenous RNA (ceRNA) theory, long non-coding RNAs (lncRNAs) can regulate the expression of target genes by adsorbing microRNAs (miRNAs/miRs). However, the role of lncRNAs in WT has not been fully elucidated. The aim of the present study was to construct a ceRNA network to identify the potential lncRNAs involved in WT. The expression profiles of lncRNAs, miRNAs and mRNAs in 120 WT and six normal tissues were obtained from the Therapeutically Applicable Research to Generate Effective Treatments database. A total of 442 lncRNAs, 214 miRNAs and 4,912 mRNAs were identified as differentially expressed in WT and were enriched in 472 Gene Ontology terms (355 biological processes, 89 cellular components and 29 molecular functions) and 18 Kyoto Encyclopedia of Genes and Genomes pathways. A lncRNA-miRNA-mRNA ceRNA network of WT consisting of with 32 lncRNAs, 14 miRNAs and 158 mRNAs was constructed, based on the bioinformatics analysis of the miR target prediction database and the miRNAcode, miRTarBase and TargetScan databases. Subsequently, three lncRNAs, three miRNAs and 17 mRNAs, which had a significant effect on the overall survival rate of patients with WT, were identified based on the survival analysis. The three lncRNAs were also differentially expressed in the late and early stages of WT and were validated using the GSE66405 dataset obtained from the Gene Expression Omnibus database. In conclusion, the present study generated a specific lncRNA-related ceRNA network of WT, which may provide a novel perspective on the molecular mechanisms underlying the progression and prognosis of the disease.

DGUOK-AS1 promotes cell proliferation in cervical cancer via acting as a ceRNA of miR-653-5p

Cervical cancer (CC) holds the second highest incidence and is the fourth dominating cause of cancer-induced death in women. It has been widely accepted that long noncoding RNAs (lncRNAs) are implicated in pathological and physiological activities of CC. However, the research of lncRNAs is still in the initial stage. The biological function of lncRNA deoxyguanosine kinase antisense RNA 1 (DGUOK-AS1) in human cancers has not been reported yet. We found that DGUOK-AS1 was aberrantly upregulated in cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) tissues through TCGA database. Real-time quantitative polymerase chain reaction (RT-qPCR) also verified the high expression of DGUOK-AS1 in CC cell lines. Loss-of-function assays indicated that DGUOK-AS1 silence repressed CC cell growth. In addition, dual-luciferase reporter and RNA immunoprecipitation (RIP) experiments validated the binding relation between miR-653-5p and DGUOK-AS1 or EMSY. Results of the rescue assays elucidated that EMSY overexpression or miR-653-5p downregulation reversed the suppressive function of DGUOK-AS1 knockdown on cell growth and DNA repair in CC. To sum up, this research highlighted that DGUOK-AS1 could promote CC cell proliferation via serving as a ceRNA of miR-653-5p to release EMSY, which might inspire us to discover novel strategies for CC treatment. SIGNIFICANCE OF THE STUDY: DGUOK-AS1 knockdown hinders proliferation of CC cells. DGUOK-AS1 sequesters miR-653-5p to elevate EMSY in CC. EMSY is required for DGUOK-AS1 to induce cell proliferation and repress DNA damage in CC.

An Emerging Class of Long Non-coding RNA With Oncogenic Role Arises From the snoRNA Host Genes

The small nucleolar RNA host genes (SNHGs) are a group of long non-coding RNAs, which are reported in many studies as being overexpressed in various cancers. With very few exceptions, the SNHGs (SNHG1, SNHG3, SNHG5, SNHG6, SNHG7, SNHG12, SNHG15, SNHG16, SNHG20) are recognized as inducing increased proliferation, cell cycle progression, invasion, and metastasis of cancer cells, which makes this class of transcripts a viable biomarker for cancer development and aggressiveness. Through our literature research, we also found that silencing of SNHGs through small interfering RNAs or short hairpin RNAs is very effective in both in vitro and in vivo experiments by lowering the aggressiveness of solid cancers. The knockdown of SNHG as a new cancer therapeutic option should be investigated more in the future.

Long non-coding RNA AFAP1-AS1 accelerates the progression of melanoma by targeting miR-653-5p/RAI14 axis

BACKGROUND

Melanoma is the most aggressive skin cancer that derived from pigment cells, accounting for the majority of the skin-cancer-related deaths. Despite great development and evolution have been made in surgery, radiotherapy and adjuvant chemotherapy, the prognosis of melanoma patients exhibited no significant improvement. Long noncoding RNAs (lncRNAs) are frequently dysregulated and involved in the development of cancers. LncRNA AFAP1-AS1 has been explored in various cancers, whereas its role and regulatory mechanism in melanoma are not well understood.

METHODS

The expression of AFAP1-AS1 was detected by qRT-PCR. CCK-8, colony formation, transwell and western blot assays were performed to investigate the biological role of AFAP1-AS1 in melanoma. Male BALB/c nude mice were applied for in vivo experiments. The interaction among AFAP1-AS1, miR-653-5p and RAI14 was investigated by RNA pull down, RIP and luciferase reporter assays.

RESULTS

AFAP1-AS1 was highly expressed in melanoma cell lines. Suppression of AFAP1-AS1 impaired cell proliferation, migration, invasion and EMT in melanoma. Moreover, AFAP1-AS1 was a ceRNA of RAI14 by competitively binding with miR-653-5p. Besides, miR-653-5p overexpression or RAI14 inhibition could repress tumor growth. Eventually, rescue assays indicated that the function of AFAP1-AS1 in the cellular process of melanoma was dependent on miR-653-5p and RAI14.

CONCLUSIONS

AFAP1-AS1 exerts its oncogenic function in melanoma by targeting miR-653-5p/RAI14 axis.

The function of SNHG7/miR-449a/ACSL1 axis in thyroid cancer

Thyroid cancer (TC) has been characterized as the most common malignant malady of the endocrine system. Small nucleolar RNA host gene 7 (SNHG7) has been reported to serve as a key regulator in a large number of human cancer types, but its role in TC and the underlying regulatory mechanism have never been evaluated yet. The present study indicated that the expression of SNHG7 was markedly higher in TC cell lines. Knockdown of SNHG7 led to a suppression of TC cell progression and migration. Acyl-CoA synthetase long-chain family member 1 (ACSL1) has also been demonstrated as an oncogene in many cancers. Herein an inhibition of ACSL1 after SNHG7 knockdown was captured. Further, the suppressing effects of SNHG7 knockdown on TC cell processes were counteracted by ACSL1 overexpression. Data from online bioinformatics analysis, RNA immunoprecipitation, and luciferase reporter assays validated the interaction between microRNA-449a (miR-449a) and SNHG7 or ACSL1. It was also verified that SNHG7 sequestered miR-449a and therefore elevated ACSL1 expression levels. To conclude, the current study indicated that SNHG7 promoted proliferation and migration of TC cells by sponging miR-449a and therefore upregulating ACSL1. The present study may provide more explorations about the molecular regulation mechanism of long noncoding RNAs in TC progression.

Downregulated long non-coding RNA SNHG7 restricts proliferation and boosts apoptosis of nasopharyngeal carcinoma cells by elevating microRNA-140-5p to suppress GLI3 expression

Long non-coding RNAs (lncRNAs) have been proposed to correlate with various carcinomas, yet the role of lncRNA SNHG7 in nasopharyngeal carcinoma (NPC) is hardly studied. This study intends to examine the molecular mechanism of SNHG7 on NPC cells. The NPC tissues and nasopharyngeal tissues of mild inflammation of nasopharyngeal mucosa were obtained. SNHG7, miR-140-5p, and GLI3 mRNA and protein expression in tissues and in the CNE1, HONE1, C666-1, CNE2, and normal NP69 cell lines was detected. IC50 and the protein expression of related drug-resistant genes of CNE2 and CNE2/DDP cells were determined. Proliferative ability, cell colony formation rate, cell cycle, and apoptosis of CNE2 and CNE2/DDP cells were also detected. SNHG7, miR-140-5p, and GLI3 mRNA and protein expression in CNE2 and CNE2/DDP cells in each group was detected. SNHG7’s cell localization, the binding sites of SNHG7 and miR-140-5p along with miR-140-5p and GLI3 were detected. Overexpressed SNHG7 and GLI3, and underexpressed miR-140-5p were found in NPC tissues and cells. SNHG7 silencing and miR-140-5p elevation declined the drug resistance of drug-resistant NPC cells and their parent cells, restrained NPC cell colony formation ability and proliferation, and boosted cell apoptosis. SNHG7 specially bound to miR-140-5p, and SNHG7 silencing elevated miR-140-5p expression. GLI3 was a direct target gene of miR-140-5p and miR-140-5p elevation diminished GLI3 expression. MiR-140-5p inhibition reversed the impacts of SNHG7 silencing on NPC cells. In summary, our study reveals that downregulated SNHG7 restricts GLI3 expression by upregulating miR-140-5p, which further suppresses cell proliferation, and promotes apoptosis of NPC.

SNHG7 Facilitates Glioblastoma Progression by Functioning as a Molecular Sponge for MicroRNA-449b-5p and Thereby Increasing MYCN Expression

BACKGROUND AND AIMS

Long noncoding RNA (small nucleolar RNA host gene 7) has been reported to be involved in multiple malignancies and acts as an oncogene. However, the potential mechanism of small nucleolar RNA host gene 7 in glioblastoma is rarely known. In this study, we attempted to elucidate the biological effects of small nucleolar RNA host gene 7 and the possible molecular mechanism in glioblastoma.

METHODS

The expression level of small nucleolar RNA host gene 7 in glioblastoma tissues and corresponding tumor cell lines was evaluated by using quantitative real-time polymerase chain reaction. Bioinformatics analyses and dual-luciferase reporter gene assay were conducted to verify the correlation among small nucleolar RNA host gene 7, miR-449b-5p, and MYCN. The role of small nucleolar RNA host gene 7 on cell viability, migration, and invasion was measured.

RESULTS

Small nucleolar RNA host gene 7 expression was markedly increased in glioblastoma tumor tissue. Small nucleolar RNA host gene 7 can sponge miR-449b-5p and negatively regulate miR-449b-5p expression. MiR-449b-5p was remarkably repressed in glioblastoma tissues. Reduction of miR-449b-5p reversed the repressive effects of small nucleolar RNA host gene 7 knockdown on cellular behaviors in glioblastoma. In addition, miR-449b-5p can directly bind with MYCN. Compared with normal samples, MYCN expression was increased. The MYCN expression was negatively related to miR-449b-5p expression while positively related to small nucleolar RNA host gene 7 expression. Rescue experiments revealed that MYCN overexpression reversed the repressive role of small nucleolar RNA host gene 7 knockdown on viability, migration, and invasion of U251 cells.

CONCLUSION

In summary, our results demonstrated that small nucleolar RNA host gene 7 regulates glioblastoma proliferation, migration, and invasion via regulating miR-449b-5p and its target gene MYCN, thereby providing a potential therapeutic target for glioblastoma.

SOX30, a target gene of miR-653-5p, represses the proliferation and invasion of prostate cancer cells through inhibition of Wnt/β-catenin signaling

BACKGROUND

Sex-determining region Y-box containing gene 30 (SOX30) is a newly identified tumor-associated gene in several types of cancer. However, whether SOX30 is involved in the development and progression of prostate cancer remains unknown. This study investigated the potential role of SOX30 in prostate cancer.

METHODS

Prostate cancer cell lines and a normal prostate epithelial cell line were used for the experiments. The expression of SOX30 was determined using quantitative real-time PCR and western blot analysis. The malignant cellular behaviors of prostate cancer were assessed using the Cell Counting Kit-8, colony formation and Matrigel invasion assays. The miRNA-mRNA interaction was validated using the dual-luciferase reporter assay.

RESULTS

SOX30 expression was lower in cells of prostate cancer lines than in cells of the normal prostate epithelial line. Its overexpression repressed the proliferation and invasion of prostate cancer cells. SOX30 was identified as a target gene of microRNA-653-5p (miR-653-5p), which is upregulated in prostate cancer tissues. MiR-653-5p overexpression decreased SOX30 expression, while its inhibition increased SOX30 expression in prostate cancer cells. MiR-653-5p inhibition also markedly restricted prostate cancer cell proliferation and invasion. SOX30 overexpression or miR-653-5p inhibition significantly reduced β-catenin expression and downregulated the activation of Wnt/β-catenin signaling. SOX30 knockdown significantly reversed the miR-653-5p inhibition-mediated inhibitory effect on the proliferation, invasion and Wnt/β-catenin signaling in prostate cancer cells.

CONCLUSIONS

These results reveal a tumor suppressive function for SOX30 in prostate cancer and confirmed the gene as a target of miR-653-5p. SOX30 upregulation due to miR-653-5p inhibition restricted the proliferation and invasion of prostate cancer cells, and this was associated with Wnt/β-catenin signaling suppression. These findings highlight the importance of the miR-653-5p-SOX30-Wnt/β-catenin signaling axis in prostate cancer progression.

SNHG7 accelerates cell migration and invasion through regulating miR-34a-Snail-EMT axis in gastric cancer

Small nucleolar RNA host gene 7 (SNHG7) is a newly recognized oncogenic Long non-coding RNA (lncRNA) in most human cancers. In gastric cancer, SNHG7 has been suggested to enhance cell proliferation and suppressed apoptosis through down-regulating P15 and P16 expression, but the effect of SNHG7 on gastric cancer cell migration and invasion was still unknown. In our study, we aimed to estimate the relationship between SNHG7 expression and clinical and pathological characteristics, and explore the effect of SNHG7 on gastric cancer cell migration and invasion. In our study, the levels of SNHG7 expression in gastric cancer tissues and cell lines were severally higher than in normal adjacent tissues and gastric mucosal epithelial cells. Moreover, high SNHG7 expression was positively correlated with TNM stage, depth of invasion, lymph-node metastasis and distant metastasis in gastric cancer patients. Furthermore, the multivariate Cox proportional hazard analysis further showed high SNHG7 expression was an independent poor prognostic factor for overall survival in gastric cancer patients. The studies in vitro revealed that SNHG7 directly binds to miR-34a and negatively regulates miR-34a expression, and SNHG7 enhances gastric cancer cell migration and invasion through suppressing miR-34a-Snail-EMT axis. In conclusion, SNHG7 functions as oncogenic lncRNA in gastric cancer and may be a potential therapeutic target for gastric cancer patients.Abbreviations: lncRNA: Long non-coding RNA; SNHG7: Small nucleolar RNA host gene 7; EMT: Epithelial mesenchymal transition; TNM: Tumor-Lymph Node-Metastasis.

Long noncoding RNA SNHG7 contributes to cell proliferation, migration, invasion and epithelial to mesenchymal transition in non-small cell lung cancer by regulating miR-449a/TGIF2 axis

Background

Non‐small cell lung cancer (NSCLC) is an intractable malignant lung cancer with high rates of metastasis and mortality. Currently, long noncoding RNA nuclear RNA host gene 7 (SNHG7) is recognized as a biomarker of multiple cancers. However, the role of SNHG7 in NSCLC requires further understanding.

Methods

The expression of SNHG7, miR‐449a and TGIF2 in NSCLC tumors and cells was examined by quantitative real time polymerase chain reaction (qRT‐PCR). Cell viability was measured by MTT assay. Cell migration and invasion was conducted using transwell assay. Protein expression of TGIF2, vimentin, N‐cadherin and E‐cadherin was detected by western blot. The interaction between miR‐449a and SNHG7 or TGIF2 was determined by luciferase reporter system, RIP and RNA pull‐down assay, respectively. Xenograft mice models were established by subcutaneously injecting A549 cells transfected with sh‐SNHG7 and sh‐control.

Results

SNHG7 expression was upregulated in NSCLC tumors and cells compared with normal tissues and cells. SNHG7 silencing repressed cell proliferation, migration, invasion and epithelial to mesenchymal transition (EMT) in NSCLC. Consistently, SNHG7 knockdown hindered tumor growth in vivo. The subsequent luciferase reporter system, RIP and RNA pull‐down assay validated the interaction between miR‐449a and SNHG7 or TGIF2. The rescue experiments displayed that miR‐449a inhibitor counteracted SNHG7 silencing induced inhibition on proliferation, migration, invasion and EMT. Similarly, restoration of TGIF2 reversed miR‐449a mediated inhibition on cell progression. In addition, the results indicated that SNHG7 could regulate cell progression by targeting miR‐449a/TGIF2 axis.

Conclusion

SNHG7 contributed to cell proliferation, migration, invasion and EMT in NSCLC by upregulating TGIF2 via sponging miR‐449a, representing a novel targeted therapy method for NSCLC.

Long Non-Coding RNA in the Pathogenesis of Cancers

The incidence and mortality rate of cancer has been quickly increasing in the past decades. At present, cancer has become the leading cause of death worldwide. Most of the cancers cannot be effectively diagnosed at the early stage. Although there are multiple therapeutic treatments, including surgery, radiotherapy, chemotherapy, and targeted drugs, their effectiveness is still limited. The overall survival rate of malignant cancers is still low. It is necessary to further study the mechanisms for malignant cancers, and explore new biomarkers and targets that are more sensitive and effective for early diagnosis, treatment, and prognosis of cancers than traditional biomarkers and methods. Long non-coding RNAs (lncRNAs) are a class of RNA transcripts with a length greater than 200 nucleotides. Generally, lncRNAs are not capable of encoding proteins or peptides. LncRNAs exert diverse biological functions by regulating gene expressions and functions at transcriptional, translational, and post-translational levels. In the past decade, it has been demonstrated that the dysregulated lncRNA profile is widely involved in the pathogenesis of many diseases, including cancer, metabolic disorders, and cardiovascular diseases. In particular, lncRNAs have been revealed to play an important role in tumor growth and metastasis. Many lncRNAs have been shown to be potential biomarkers and targets for the diagnosis and treatment of cancers. This review aims to briefly discuss the latest findings regarding the roles and mechanisms of some important lncRNAs in the pathogenesis of certain malignant cancers, including lung, breast, liver, and colorectal cancers, as well as hematological malignancies and neuroblastoma.