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

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.

Signaling pathways and therapeutic interventions in gastric cancer

Gastric cancer (GC) ranks fifth in global cancer diagnosis and fourth in cancer-related death. Despite tremendous progress in diagnosis and therapeutic strategies and significant improvements in patient survival, the low malignancy stage is relatively asymptomatic and many GC cases are diagnosed at advanced stages, which leads to unsatisfactory prognosis and high recurrence rates. With the recent advances in genome analysis, biomarkers have been identified that have clinical importance for GC diagnosis, treatment, and prognosis. Modern molecular classifications have uncovered the vital roles that signaling pathways, including EGFR/HER2, p53, PI3K, immune checkpoint pathways, and cell adhesion signaling molecules, play in GC tumorigenesis, progression, metastasis, and therapeutic responsiveness. These biomarkers and molecular classifications open the way for more precise diagnoses and treatments for GC patients. Nevertheless, the relative significance, temporal activation, interaction with GC risk factors, and crosstalk between these signaling pathways in GC are not well understood. Here, we review the regulatory roles of signaling pathways in GC potential biomarkers, and therapeutic targets with an emphasis on recent discoveries. Current therapies, including signaling-based and immunotherapies exploited in the past decade, and the development of treatment for GC, particularly the challenges in developing precision medications, are discussed. These advances provide a direction for the integration of clinical, molecular, and genomic profiles to improve GC diagnosis and treatments.

The roles of long noncoding RNAs in the regulation of OCT4 expression

OCT4 is a major transcription factor that maintains the pluripotency of stem cells, including embryonic stem cells, induced pluripotent stem cells and cancer stem cells. An increasing number of long noncoding RNAs have been reported to participate in the regulation of OCT4 expression through various mechanisms, including binding with the OCT4 gene promoter to regulate local methylation; promoting chromosomal spatial folding to form an inner ring, thereby aggregating OCT4 cis-acting elements scattered in discontinuous sites of the chromosome; competitively binding microRNAs with OCT4 to upregulate OCT4 expression at the posttranscriptional level; and sharing a promoter with OCT4. Moreover, the transcription of some long noncoding RNAs is regulated by OCT4, and certain long noncoding RNAs form feedback regulatory loops with OCT4. In this review, we summarized the research progress of the long noncoding RNAs involved in the regulation of OCT4 expression.

Long non-coding RNAs and cancer mechanisms: Immune cells and inflammatory cytokines in the tumor microenvironment

Chronic inflammation and immune response are two central hallmarks of the tumor microenvironment (TME), teeming with immune cells and inflammatory cytokines that promote tumor progression. Intriguingly, there is mutual regulation between immune cells and cytokines. Indeed, the differentiation and function of immune cells depend on cytokines secreted from tumor cells, whereas immune activation affects the dynamics of cytokines, reshaping the TME together. Long non-coding RNAs (lncRNAs) as a blooming molecule are virtually involved in physiology and pathology events, especially TME. Notably, the regulatory loop between lncRNAs and cytokines or immune activation plays a vital role in tumor growth. Thus, this review concentrates on the interaction between lncRNAs and immune cells. It puts special attention to the intertwist between lncRNAs and cytokines or immune cells, providing a theoretical basis for lncRNAs as a potential biomarker and therapeutic tumor target.

ARL2 is required for homologous recombination repair and colon cancer stem cell survival

ARL2 regulates the dynamics of cytological components and is highly expressed in colon cancer tissues. Here, we report novel roles of ARL2 in the cell nucleus and colon cancer stem cells (CSCs). ARL2 is expressed at relatively low levels in K‐RAS active colon cancer cells, but its expression is induced in CSCs. Depletion of ARL2 results in M phase arrest exclusively in non‐CSC cultured cells; in addition, DNA break stress accumulates in CSCs leading to apoptosis. ARL2 expression is positively associated with the expression of all six RAD51 family genes, which are essential for homologous recombination repair (HRR). Furthermore, ARL2 is required for HRR and detected within chromatin compartments. These results demonstrate the requirement of ARL2 in colon CSC maintenance, which possibly occurs through mediating double‐strand break DNA repair in the nucleus.

Identification of m6A-Related lncRNA to Predict the Prognosis of Patients with Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. In the past decades, HCC treatment has achieved great progress; however, the overall prognosis remains poor. Therefore, it is the need of the hour to identify new prognostic biomarkers which can advance our understanding related to the underlying molecular mechanism of adverse prognosis and apply them to clinical work in prognosis prediction. In the present study, data of 576 HCC patients and 292 normal control cases from TCGA and ICGC databases were enrolled to our bioinformatic analysis. SNHG1 and SNHG3 were identified as overlapping genes in TCGA and ICGC databases using Pearson correlation analysis and univariate Cox regression analysis. Further, we used the median of the SNHG1 and SNHG3 expression values as the cutoff values to define the HCC patient groups with high or low expression level. The subsequent analysis revealed that abnormal high expression of SNHG1 or SNHG3 affected the immune infiltration patterns and the crosstalk among immune cells. Moreover, high expression of SNHG1 or SNHG3 resulted in drug resistant to AKT inhibitor VII, bexarotene, bicalutamide, dasatinib, erlotinib, and gefitinib. In addition, lower tumor neoantigen burden was observed in high SNHG1 or SNHG3 group. Further, we found significant relation between the aberrant upregulation of SNHG1 and SNHG3 in tumor grade and stage. We established a nomogram to systematically predict the 5- and 8-year overall survival of liver cancer patients with good accuracy. Finally, the in vitro assays suggest that SNHG1 and SNHG3 promote the proliferative, migratory, and invasive abilities of HCC cells.

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

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

Major Role for Cellular MicroRNAs, Long Noncoding RNAs (lncRNAs), and the Epstein-Barr Virus-Encoded BART lncRNA during Tumor Growth In Vivo

This study assessed the effects of Epstein-Barr virus (EBV) and one form of virally encoded BART long noncoding RNAs (lncRNAs) on cellular expression in epithelial cells grown in vitro and as tumors in vivo determined by high-throughput RNA sequencing of mRNA and small RNAs. Hierarchical clustering based on gene expression distinguished the cell lines from the tumors and distinguished the EBV-positive tumors and the BART tumors from the EBV-negative tumors. EBV and BART expression also induced specific expression changes in cellular microRNAs (miRs) and lncRNAs. Multiple known and predicted targets of the viral miRs, the induced cellular miRs, and lncRNAs were identified in the altered gene set. The changes in expression in vivo indicated that the suppression of growth pathways in vivo reflects increased expression of cellular miRs in all tumors. In the EBV and BART tumors, many of the targets of the induced miRs were not changed and the seed sequences of the nonfunctional miRs were found to have homologous regions within the BART lncRNA. The inhibition of these miR effects on known targets suggests that these induced miRs have reduced function due to sponging by the BART lncRNA. This composite analysis identified the effects of EBV on cellular miRs and lncRNAs with a functional readout through identification of the simultaneous effects on gene expression. Major shifts in gene expression in vivo are likely mediated by effects on cellular noncoding RNAs. Additionally, a predicted property of the BART lncRNA is to functionally inhibit the induced cellular miRs.

Comprehensive analysis of N6-methylandenosine regulators and m6A-related RNAs as prognosis factors in colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies and has been a leading cause of cancer-related death worldwide in recent years. N6-methyladenosine (m6A) methylation is the most abundant epigenetic modification of various types of RNAs, and it plays a vital role in promoting cancer development. Here, we obtained SNV and transcriptome data of CRC from The Cancer Genome Atlas (TCGA). We demonstrated that most m6A methylation regulators were aberrantly expressed in individuals with CRC. The abnormal expression of m6A regulators was caused by their different copy number variation (CNV) patterns, and alteration of m6A regulators was significantly correlated with prognosis and tumor stage. By using weighted coexpression network analysis (WGCNA), we identified m6A-related long noncoding RNAs (lncRNAs) and mRNAs; then we used least absolute shrinkage and selection operator (LASSO) Cox regression analysis to construct m6A-related lncRNA and mRNA prognostic signatures in the TCGA dataset. Furthermore, a nomogram with clinicopathological features, lncRNA risk scores, and mRNA risk scores was established, which showed a strong ability to forecast the overall survival of the individuals with CRC in training and testing sets. In conclusion, m6A methylation regulators played a vital role in affecting the prognosis of subjects with CRC, and m6A-related lncRNAs and mRNAs revealed underlying mechanisms in CRC tumorigenesis and progression.

Long Non-Coding RNA in Gastric Cancer: Mechanisms and Clinical Implications for Drug Resistance

Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide, with high recurrence and mortality rate. Chemotherapy, including 5-fluorouracil (5-FU), adriamycin (ADR), vincristine (VCR), paclitaxel (PTX), and platinum drugs, remains one of the fundamental methods of GC treatment and has efficiently improved patients’ prognosis. However, most patients eventually develop resistance to chemotherapeutic agents, leading to the failure of clinical treatment and patients’ death. Recent studies suggest that long non-coding RNAs (lncRNAs) are involved in the drug resistance of GC by modulating the expression of drug resistance-related genes via sponging microRNAs (miRNAs). Moreover, lncRNAs also play crucial roles in GC drug resistance via a variety of mechanisms, such as the regulation of the oncogenic signaling pathways, inhibition of apoptosis, induction of autophagy, modulation of cancer stem cells (CSCs), and promotion of the epithelial-to-mesenchymal transition (EMT) process. Some of lncRNAs exhibit great potential as diagnostic and prognostic biomarkers, as well as therapeutic targets for GC patients. Therefore, understanding the role of lncRNAs and their mechanisms in GC drug resistance may provide us with novel insights for developing strategies for individual diagnosis and therapy. In this review, we summarize the recent findings on the mechanisms underlying GC drug resistance regulated by lncRNAs. We also discuss the potential clinical applications of lncRNAs as biomarkers and therapeutic targets in GC.

An updated review of the contribution of noncoding RNAs to the progression of gastric cancer stem cells: Molecular mechanisms of viability, invasion, and chemoresistance of gastric cancer stem cells

Gastric cancer (GC) is a leading cause of death and cancer mortality in the world, with poor survival for cases with higher stages of GC. During the past decade, GC stem cells (GCSCs) - a group of cancer cells- have been the focus of numerous cancer researches. GCSCs have the capability of self-renewal and are identified to be participated in GC development, invasion, chemoresistance, and tumor relapse. Research projects have indicated the main activities of noncoding RNAs in cellular pathways. Micro (mi)RNAs and lncRNAs play important functions in the modulation of different cellular pathways in the post-transcriptional form, through their dysregulated expression in several cancers, including GC. In this paper, we highlight the impact of dysregulated expression of micro-and lncRNAs and their downstream transcripts on GCSCs. Data collection about the progression of GCSCs may be beneficial for the introduction of new insights to the GC treatment.

Common Pathogenetic Mechanisms Underlying Aging and Tumor and Means of Interventions

Recently, there has been an increase in the incidence of malignant tumors among the older population. Moreover, there is an association between aging and cancer. During the process of senescence, the human body suffers from a series of imbalances, which have been shown to further accelerate aging, trigger tumorigenesis, and facilitate cancer progression. Therefore, exploring the junctions of aging and cancer and searching for novel methods to restore the junctions is of great importance to intervene against aging-related cancers. In this review, we have identified the underlying pathogenetic mechanisms of aging-related cancers by comparing alterations in the human body caused by aging and the factors that trigger cancers. We found that the common mechanisms of aging and cancer include cellular senescence, alterations in proteostasis, microbiota disorders (decreased probiotics and increased pernicious bacteria), persistent chronic inflammation, extensive immunosenescence, inordinate energy metabolism, altered material metabolism, endocrine disorders, altered genetic expression, and epigenetic modification. Furthermore, we have proposed that aging and cancer have common means of intervention, including novel uses of common medicine (metformin, resveratrol, and rapamycin), dietary restriction, and artificial microbiota intervention or selectively replenishing scarce metabolites. In addition, we have summarized the research progress of each intervention and revealed their bidirectional effects on cancer progression to compare their reliability and feasibility. Therefore, the study findings provide vital information for advanced research studies on age-related cancers. However, there is a need for further optimization of the described methods and more suitable methods for complicated clinical practices. In conclusion, targeting aging may have potential therapeutic effects on aging-related cancers.

Long non-coding RNAs: Biogenesis, functions, and clinical significance in gastric cancer

Gastric cancer (GC) is one of the most prevalent malignant tumor types and the third leading cause of cancer-related death worldwide. Its morbidity and mortality are very high due to a lack of understanding about its pathogenesis and the slow development of novel therapeutic strategies. Long non-coding RNAs (lncRNAs) are a class of non-coding RNAs with a length of more than 200 nt. They play crucial roles in a wide spectrum of physiological and pathological processes by regulating the expression of genes involved in proliferation, differentiation, apoptosis, cell cycle, invasion, metastasis, DNA damage, and carcinogenesis. The aberrant expression of lncRNAs has been found in various cancer types. A growing amount of evidence demonstrates that lncRNAs are involved in many aspects of GC pathogenesis, including its occurrence, metastasis, and recurrence, indicating their potential role as novel biomarkers in the diagnosis, prognosis, and therapeutic targets of GC. This review systematically summarizes the biogenesis, biological properties, and functions of lncRNAs and highlights their critical role and clinical significance in GC. This information may contribute to the development of better diagnostics and treatments for GC.

LncRNA SNHG3 promotes gastric cancer cell proliferation and metastasis by regulating the miR-139-5p/MYB axis

The long non-coding RNA (lncRNA) SNHG3 has been shown to play oncogenic roles in several cancer types, but the mechanisms underlying its activity are poorly understood. In this study, we aimed to explore the clinical relevance and mechanistic role of SNHG3 in gastric cancer (GC). We found that SNHG3 expression in GC cell lines and tissues was significantly increased, and the upregulation of this lncRNA was correlated with tumor clinical stage and decreased patient survival. Knocking down SNHG3 in GC cells impaired the proliferative, migratory, and invasive activity in vitro and constrained in vivo GC xenograft tumor growth. Mechanistically, SNHG3 was found to bind and sequester miR-139-5p, thereby indirectly promoting the upregulation of the miR-139-5p target gene MYB. These data demonstrated that SNHG3 functions in an oncogenic manner to drive GC proliferation, migration, and invasion by regulating the miR-139-5p/MYB axis.

The role of non-coding RNAs in chemotherapy for gastrointestinal cancers

Gastrointestinal (GI) cancers, including colorectal, gastric, hepatic, esophageal, and pancreatic tumors, are responsible for large numbers of deaths around the world. Chemotherapy is the most common approach used to treat advanced GI cancer. However, chemoresistance has emerged as a critical challenge that prevents successful tumor elimination, leading to metastasis and recurrence. Chemoresistance mechanisms are complex, and many factors and pathways are involved. Among these factors, non-coding RNAs (ncRNAs) are critical regulators of GI tumor development and subsequently can induce resistance to chemotherapy. This occurs because ncRNAs can target multiple signaling pathways, affect downstream genes, and modulate proliferation, apoptosis, tumor cell migration, and autophagy. ncRNAs can also induce cancer stem cell features and affect the epithelial-mesenchymal transition. Thus, ncRNAs could possibly act as new targets in chemotherapy combinations to treat GI cancer and to predict treatment response.

Non-Coding RNAs in Gastric Cancer: From Malignant Hallmarks to Clinical Applications

Gastric cancer (GC) is one of the most lethal malignancies worldwide. However, the molecular mechanisms underlying gastric carcinogenesis remain largely unknown. Over the past decades, advances in RNA-sequencing techniques have greatly facilitated the identification of various non-coding RNAs (ncRNAs) in cancer cells, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Accumulating evidence has revealed that ncRNAs are essential regulators in GC occurrence and development. However, ncRNAs represent an emerging field of cancer research, and their complex functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets in GC, further studies should focus on elucidating the intricate relationships between ncRNAs and GC, which can be translated into clinical practice. In this review, we summarize recent research progress on how ncRNAs modulate the malignant hallmarks of GC, especially in tumor immune escape, drug resistance, and stemness. We also discuss the promising applications of ncRNAs as diagnostic biomarkers and therapeutic targets in GC, aiming to validate their practical value for clinical treatment.

Long non-coding RNA SNHG3 promotes the progression of clear cell renal cell carcinoma via regulating BIRC5 expression

Background

Research has shown that the progression of clear cell renal cell carcinoma (ccRCC) is modulated by long non-coding RNAs (lncRNAs). However, the roles of specific lncRNAs in the malignancy of ccRCC are still unknown.

Methods

TCGA and GSE66272 datasets were used to predict differentially expressed genes (DEGs) in ccRCC. ENCORI database was employed to display BIRC5 miRNA network and potential lncRNA interactions for miRNAs. KM plotter and correlation analyses were performed to identify the overall survival (OS)- and BIRC5-related miRNAs. Quantitative real-time PCR (qRT-PCR) was used to verify the BIRC5 mRNA in the seventy paired clinical samples of ccRCC tissues. The ccRCC A498 and 786-O were individually transfected with lncRNA SNHG3 and LINC00997 and then western blotting was used to detect the BIRC5 protein expression. The Dual-luciferase reporter assay was used to examine the regulatory interaction between lncRNA SNHG3 and microRNA (miRNA/miR)-10b-5p.

Results

BICR5 is associated with the progression of ccRCC. The two novel lncRNAs (LINC00997, SNHG3) were up-regulated in ccRCC tissues and positively with the BICR5 protein expression. However, Suppressing SNHG3 expression reduced BIRC5 protein expression compared with the LINC00997, most importantly, Suppressing SNHG3 expression suppressed tumor progression in vitro. In addition, SNHG3 promotes the expression of BIRC5 protein by sponging microRNA-10b-5p.

Conclusions

Our findings suggest that SNHG3 plays a vital role in promoting ccRCC via the microRNA-10b-5p/BIRC5 axis and may serve as a novel therapeutic target for the treatment of patients with ccRCC.

MicroRNAs regulating SOX2 in cancer progression and therapy response

The proliferation, metastasis and therapy response of tumour cells are tightly regulated by interaction among various signalling networks. The microRNAs (miRNAs) can bind to 3'-UTR of mRNA and down-regulate expression of target gene. The miRNAs target various molecular pathways in regulating biological events such as apoptosis, differentiation, angiogenesis and migration. The aberrant expression of miRNAs occurs in cancers and they have both tumour-suppressor and tumour-promoting functions. On the contrary, SOX proteins are capable of binding to DNA and regulating gene expression. SOX2 is a well-known member of SOX family that its overexpression in different cancers to ensure progression and stemness. The present review focuses on modulatory impact of miRNAs on SOX2 in affecting growth, migration and therapy response of cancers. The lncRNAs and circRNAs can function as upstream mediators of miRNA/SOX2 axis in cancers. In addition, NF-κB, TNF-α and SOX17 are among other molecular pathways regulating miRNA/SOX2 axis in cancer. Noteworthy, anti-cancer compounds including bufalin and ovatodiolide are suggested to regulate miRNA/SOX2 axis in cancers. The translation of current findings to clinical course can pave the way to effective treatment of cancer patients and improve their prognosis.

A novel lncRNA-protein interaction prediction method based on deep forest with cascade forest structure

Long noncoding RNAs (lncRNAs) regulate many biological processes by interacting with corresponding RNA-binding proteins. The identification of lncRNA-protein Interactions (LPIs) is significantly important to well characterize the biological functions and mechanisms of lncRNAs. Existing computational methods have been effectively applied to LPI prediction. However, the majority of them were evaluated only on one LPI dataset, thereby resulting in prediction bias. More importantly, part of models did not discover possible LPIs for new lncRNAs (or proteins). In addition, the prediction performance remains limited. To solve with the above problems, in this study, we develop a Deep Forest-based LPI prediction method (LPIDF). First, five LPI datasets are obtained and the corresponding sequence information of lncRNAs and proteins are collected. Second, features of lncRNAs and proteins are constructed based on four-nucleotide composition and BioSeq2vec with encoder-decoder structure, respectively. Finally, a deep forest model with cascade forest structure is developed to find new LPIs. We compare LPIDF with four classical association prediction models based on three fivefold cross validations on lncRNAs, proteins, and LPIs. LPIDF obtains better average AUCs of 0.9012, 0.6937 and 0.9457, and the best average AUPRs of 0.9022, 0.6860, and 0.9382, respectively, for the three CVs, significantly outperforming other methods. The results show that the lncRNA FTX may interact with the protein P35637 and needs further validation.

[Role of long noncoding RNA SNHG3 in regulating proliferation, migration and invasion of cervical cancer SiHa cells]

OBJECTIVE

To investigate the regulatory role of the long non-coding RNA (lncRNA) small nucleolar host gene 3 (SNHG3) in proliferation, migration and invasion of human cervical cancer cell line SiHa.

OBJECTIVE

Array data were retrieved from GEO database to analyze the expression levels of SNHG3 in cervical cancer and adjacent normal tissues. SiHa cells were transfected with a small interfering RNA (siRNA) targeting SNHG3, and the changes in the transcriptional levels of lncRNA SNHG3 and the epithelial-mesenchymal transition (EMT) markers N-cadherin, Snail, vimentin and E-cadherin were detected using real-time quantitative PCR; the protein expressions of N-cadherin, Snail, vimentin and E-cadherin were determined using Western blotting. Cell counting kit-8 (CCK8) assay was utilized to assess the proliferation capacity of the transfected cells. Wound healing assay and Transwell assay were performed to evaluate the transversal and longitudinal migration and invasion abilities of the cells.

OBJECTIVE

SNHG3 was over-expressed in cervical cancer tissues and SiHa cells. In SiHa cells, knocking down SNHG3 significantly inhibited the proliferation (P < 0.001), migration (P < 0.01) and invasion abilities (P < 0.001) of the cells, down-regulated the expression levels of N-cadherin, Snail and vimentin (P < 0.001) and up-regulated the expression of E-cadherin (P < 0.001).

OBJECTIVE

SNHG3 may promote the proliferation, migration and invasion of SiHa cells by activating the EMT signaling pathway.