Molecular mechanisms of lncRNA SMARCC2/miR-551b-3p/TMPRSS4 axis in gastric cancer

Identification of a miRNA multi-targeting therapeutic strategy in glioblastoma

Glioblastoma (GBM) is a deadly and the most common primary brain tumor in adults. Due to their regulation of a high number of mRNA transcripts, microRNAs (miRNAs) are key molecules in the control of biological processes and are thereby promising therapeutic targets for GBM patients. In this regard, we recently reported miRNAs as strong modulators of GBM aggressiveness. Here, using an integrative and comprehensive analysis of the TCGA database and the transcriptome of GBM biopsies, we identified three critical and clinically relevant miRNAs for GBM, miR-17-3p, miR-222, and miR-340. In addition, we showed that the combinatorial modulation of three of these miRNAs efficiently inhibited several biological processes in patient-derived GBM cells of all these three GBM subtypes (Mesenchymal, Proneural, Classical), induced cell death, and delayed tumor growth in a mouse tumor model. Finally, in a doxycycline-inducible model, we observed a significant inhibition of GBM stem cell viability and a significant delay of orthotopic tumor growth. Collectively, our results reveal, for the first time, the potential of miR-17-3p, miR-222 and miR-340 multi-targeting as a promising therapeutic strategy for GBM patients.

TMPRSS4, a type II transmembrane serine protease, as a potential therapeutic target in cancer

Proteases are involved in almost all biological processes, implying their importance for both health and pathological conditions. Dysregulation of proteases is a key event in cancer. Initially, research identified their role in invasion and metastasis, but more recent studies have shown that proteases are involved in all stages of cancer development and progression, both directly through proteolytic activity and indirectly via regulation of cellular signaling and functions. Over the past two decades, a novel subfamily of serine proteases called type II transmembrane serine proteases (TTSPs) has been identified. Many TTSPs are overexpressed by a variety of tumors and are potential novel markers of tumor development and progression; these TTSPs are possible molecular targets for anticancer therapeutics. The transmembrane protease serine 4 (TMPRSS4), a member of the TTSP family, is upregulated in pancreatic, colorectal, gastric, lung, thyroid, prostate, and several other cancers; indeed, elevated expression of TMPRSS4 often correlates with poor prognosis. Based on its broad expression profile in cancer, TMPRSS4 has been the focus of attention in anticancer research. This review summarizes up-to-date information regarding the expression, regulation, and clinical relevance of TMPRSS4, as well as its role in pathological contexts, particularly in cancer. It also provides a general overview of epithelial-mesenchymal transition and TTSPs.

LncRNA PVT1 delays skin photoaging by sequestering miR-551b-3p to release AQP3 expression via ceRNA mechanism

Understanding human skin photoaging requires in-depth knowledge of the molecular and functional mechanisms. Human dermal fibroblasts (HDFs) gradually lose their ability to produce collagen and renew intercellular matrix with aging. Therefore, our study aims to reveal the mechanistic actions of a novel ceRNA network in the skin photoaging by regulating HDF activities. Photoaging-related genes were obtained in silico, followed by GO and KEGG enrichment analyses. Differentially expressed lncRNAs and miRNAs were screened from the GEO database to construct the ceRNA co-expression network. In skin photoaging samples, PVT1 and AQP3 were poorly expressed, while miR-551b-3p was highly expressed. The relationships among the lncRNA, miRNA and mRNA were explored through the ENCORI database and dual luciferase reporter assay. Mechanistically, PVT1 could sequester miR-551b-3p to upregulate the expression of AQP3, which further inactivated the ERK/p38 MAPK signaling pathway. HDFs were selected to construct an in vitro cell skin photoaging model, where the senescence, cell cycle distribution and viability of young and senescent HDFs were detected by SA-β-gal staining, flow cytometry and CCK-8 assay. In vitro cell experiments confirmed that overexpression of PVT1 or AQP3 enhanced viability of young and senescent HDFs and inhibited HDF senescence, while miR-551b-3p upregulation counteracted the effect of PVT1. In conclusion, PVT1-driven suppression of miR-551b-3p induces AQP3 expression to inactivate the ERK/p38 MAPK signaling pathway, thereby inhibiting HDF senescence and ultimately delaying the skin photoaging.

Extracellular RNA as a kind of communication molecule and emerging cancer biomarker

Extracellular RNA (exRNA) is a special form of RNA in the body. RNA carries information about genes and metabolic regulation in the body, which can reflect the real-time status of cells. This characteristic renders it a biomarker for disease diagnosis, treatment, and prognosis. ExRNA is transported through extracellular vesicles as a signal medium to mediate communication between cells. Tumor cells can release more vesicles than normal cells, thereby promoting tumor development. Depending on its easy detection, the advantages of non-invasive molecular diagnostic technology can be realized. In this systematic review, we present the types, vectors, and biological value of exRNA. We briefly describe new methods of tumor diagnosis and treatment, as well as the difficulties faced in the progress of such research. This review highlights the groundbreaking potential of exRNA as a clinical biomarker.

TMPRSS4 is a novel biomarker and correlated with immune infiltration in thyroid carcinoma

Transmembrane protease serine 4 (TMPRSS4) is a cancer-associated protease associated with prognosis in various types of cancer. Mechanistically, TMPRSS4 mainly regulates malignant phenotypes, such as tumor invasion and metastasis, by either the epithelial to mesenchymal transition (EMT) program or promoting the proliferation of cancer cells. To date, TMPRSS4 and immune infiltration in thyroid carcinoma (TC) are largely unknown. Thus, this paper evaluated the expression of TMPRSS4 in tumor tissue through the Tumor Immune Estimation Resource (TIMER) database, and Oncomine, and its correlation with clinical parameters by UALCAN databases. Furthermore, we analyzed its prognostic value from Kaplan-Meier Plotter database, and the relationship between TMPRSS4 and the abundance of tumor-infiltrating lymphocytes (TILs) in TC in TISIDB, screening potential immune targets to explore novel mechanisms for the clinical management of TC. Finally, we assessed the correlation between TMPRSS4 and some immune markers to uncover a potential immune-related biomarker in TC patients by TIMER2.0. The results revealed that TMPRSS4 was highly expressed in TC and was also associated with lymphatic metastasis, advanced stage, histological subtype, and favorable clinical outcome. The stratified analysis based on immune cell content showed that decreased TMPRSS4 had worse prognosis in CD8⁺ T cell-enriched TC patients. TMPRSS4 was positively correlated with tumor immune infiltration and the expression of gene markers of immune cells. Notably, its expression was lower in the lymphocyte-depleted subtype than in other immunosubtypes in TC. Moreover, TMPRSS4 was closely related to chemokines as well as their receptors and the immunosuppressive checkpoints CTLA-4, PD-1, and HLA-G. In conclusion, TMPRSS4 may act as a novel biomarker predicting prognosis and immune infiltration in TC.

A Novel Matrisomal-Related LncRNA Signature Associated With Survival Outcome and Immune Evasion in Patients With Gastric Cancer

Background

Different matrisomal patterns are shared across carcinomas. However, little is known about whether there exists a unique tumor matrisome that modulates GC progression and immune regulation.

Methods

We conducted a genome-wide analysis based on matrisomal-related lncRNAs (MRLs) in 375 patients with GC from the Cancer Genome Atlas (TCGA) database. Patients were split into the training set and validation set at a ratio of 1:1 using the R package cart. Pearson correlation analysis (PCA) was performed to identify lncRNAs that correlated with matrisome based on differential expression genes. Subsequently, we performed univariate Cox regression analyses and lasso Cox analysis on these lncRNAs to construct a risk model. Considering the primary effect of GRASLND on the GC prognosis, we chose it for further validation in an experimental setting.

Results

We identified a 15-MRL signature to predict overall survival and immune cell infiltration of patients with GC. The AUC values to predict 5-year outcome in three sets were 0.89, 0.65, and 0.78, respectively. Further analyses suggested that the high-risk group showed more obvious immune cell infiltration, and demonstrated an immunologically “cold” profile. In vitro, knockdown of GRASLND could inhibit the invasion capability of GC cells, and downregulate the protein expression of crucial matrisomal-related gene MMP9.

Conclusions

The 15-MRL gene signature might serve as a relatively good predictive tool to manage patients with GC.

Identification and Validation of Dilated Cardiomyopathy-Related Genes via Bioinformatics Analysis

Purpose

Dilated cardiomyopathy (DCM) is a type of cardiomyopathy that can easily cause heart failure and has a high mortality rate. Therefore, there is an urgent need to study the underlying mechanism of action of dilated cardiomyopathy. In the present study, we aimed to explore potential miRNA–mRNA pairs and drugs related to DCM.

Methods

The Microarray data were collected from the Gene Expression Omnibus (GEO) database. Bioinformatics analysis differentially expressed miRNAs and mRNAs in each microarray were obtained. The target genes of miRNAs were obtained from the miRWalk 2.0 database, and the intersection of these two gene sets (miRNA target genes and differentially expressed mRNAs in the microarray) was obtained. Pathway and Gene Ontology (GO) enrichment analyses were performed in the KOBAS database. Cytoscape software was used to construct the miRNA–mRNA network, and the final hub genes were obtained. Furthermore, we predicted several candidate drugs related to hub genes using DSigDB database. To confirm the abnormal expression of hub genes, qRT-PCR was performed.

Results

In total, eight differentially expressed miRNAs and 92 differentially expressed mRNAs were identified. In addition, 47 differentially expressed miRNA target genes were identified. According to the analysis results of the miRNA-mRNA network, we identified hsa-miR-551b-3p, hsa-miR-770-5p, hsa-miR-363-3p, PIK3R1, DDIT4, and CXCR4 as hub genes in DCM. Several candidate drugs, which are related to the hug genes, were identified.

Conclusion

In conclusion, in our study, we identified several hub genes that may be involved in the pathogenesis of DCM. Several drugs related to these hub genes may be used as clinical therapeutic candidates.

Gastric cancer: An epigenetic view

Gastric cancer (GC) poses a serious threat worldwide with unfavorable prognosis mainly due to late diagnosis and limited therapies. Therefore, precise molecular classification and search for potential targets are required for diagnosis and treatment, as GC is complicated and heterogeneous in nature. Accumulating evidence indicates that epigenetics plays a vital role in gastric carcinogenesis and progression, including histone modifications, DNA methylation and non-coding RNAs. Epigenetic biomarkers and drugs are currently under intensive evaluations to ensure efficient clinical utility in GC. In this review, key epigenetic alterations and related functions and mechanisms are summarized in GC. We focus on integration of existing epigenetic findings in GC for the bench-to-bedside translation of some pivotal epigenetic alterations into clinical practice and also describe the vacant field waiting for investigation.

LncRNA HLA Complex Group 11 Knockdown Alleviates Cisplatin Resistance in Gastric Cancer by Targeting the miR-144-3p/UBE2D1 Axis

OBJECTIVE

Cisplatin (DDP) treatment is one of the most predominant chemotherapeutic strategies for patients with gastric cancer (GC). LncRNA noncoding RNA HLA complex group 11 (lncRNA HCG11) has been confirmed to promote GC progression. This study attempted to investigate the underlying molecular mechanism of HCG11 in DDP resistance of GC.

METHODS

qRT-PCR was performed to evaluate the expression of HCG11, microRNA-144-3p (miR-144-3p), and ubiquitin-conjugating enzyme E2 D1 (UBE2D1) in GC. The correlation between HCG11 and clinicopathological features of GC patients was assessed. DDP-resistant GC cells and their parental cells were cultured in different concentrations of DDP. The role of HCG11 for the viability and the half maximal inhibitory concentration (IC50) of DDP in DDP-resistant GC cells was determined by MTT assay. Then, the invasion of DDP-resistant GC cells was measured by transwell assay. Next, a dual-luciferase reporter assay was used to confirm the interactions among HCG11, miR-144-3p, and UBE2D1 in GC.

RESULTS

The expression of HCG11 and UBE2D1 was elevated in tumor tissues of GC patients, but miR-144-3p was declined. HCG11 expression was elevated in DDP-resistant GC patients and is strongly correlated with DDP sensitivity and World Health Organization grade in GC patients. HCG11 knockdown reduced the viability, IC50 of DDP, and invasion of DDP-resistant GC cells. Additionally, HCG11 targeted miR-144-3p and miR-144-3p further targeted UBE2D1. Feedback experiments indicated that low expression of miR-144-3p or overexpression of UBE2D1 mitigated the inhibitory effect of HCG11 depletion on DDP resistance of GC cells.

CONCLUSION

HCG11 knockdown attenuated DDP resistance of GC cells through via miR-144-3p/UBE2D1 axis, affording a novel therapeutic strategy for GC.

Moderate Prognostic Value of lncRNA FOXD2-AS1 in Gastric Cancer with Helicobacter pylori Infection

PURPOSE

Gastric cancer (GC) is one of the most frequent tumors worldwide and identification of a sensitive and specific prognostic biomarker is of great importance. Long non-coding RNAs (lncRNAs) play crucial roles in tumorigenesis of various malignancies. In the present study, we investigated lncRNA FOXD2-AS1 expression in gastric tumors and assessed its potential as a prognostic biomarker.

METHODS

A total of 95 tumor and corresponding adjacent non-tumor tissue specimens were collected from patients with GC from Imam Reza hospital, Tabriz, Iran. Total RNA was isolated and FOXD2-AS1 expression was measured using quantitative reverse transcriptase (qRT)-PCR.

RESULTS

FOXD2-AS1 was significantly upregulated in tumor samples as compared to non-tumor tissues (P < 0.0001). In addition, higher expression of FOXD2-AS1 was significantly associated with lymph node metastasis and Helicobacter pylori infection. The receiver operating characteristic (ROC) curve analysis revealed that FOXD2-AS1 might be served as a potential prognostic biomarker for GC.

CONCLUSION

FOXD2-AS1 is upregulated in gastric tumors and can be used as a valuable biomarker in the prognosis of patients with GC.

LncRNA PVT1 Facilitates Proliferation, Migration and Invasion of NSCLC Cells via miR-551b/FGFR1 Axis

Background

Long non-coding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) plays a crucial role in non-small cell lung cancer (NSCLC). Nonetheless, regulatory effects of PVT1 on functions of NSCLC cells remain blurry.

Methods

Relative expression levels of PVT1, miR-551b and FGFR1 mRNA in tumor tissues and cells were examined employing quantitative real-time polymerase chain reaction (qRT-PCR); CCK-8 and BrdU assays were utilized for measuring cell viability and proliferation of H1299 and A549 cells; cell migration and invasion were detected deploying Transwell assay; dual-luciferase assay was used for the validation of binding sequence between PVT1 and miR-551b. FGFR1 expression in protein level was quantified employing Western blot.

Results

PVT1 was highly expressed in NSCLC tissues and cell lines, whereas miR-551b expression was down-regulated. Overexpression of PVT1 potentiated viability, proliferation, migration and invasion of NSCLC cells while miR-551b inhibited the biological behaviors mentioned above. MiR-551b was predicted and then confirmed as a direct downstream target of PVT1. Meanwhile, a negative correlation was observed between PVT1 expression and miR-551b expression in NSCLC tissues. Besides, PVT1 could increase FGFR1 expression by repressing miR-551b expression.

Conclusion

PVT1 promotes the proliferation, migration and invasion of NSCLC cells by indirectly mediating FGFR1 via targeting miR-551b.

Identification of prognostic alternative splicing events related to the immune microenvironment of hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world, and its 5-year survival rate is less than 20%, despite various treatments being available. Increasing evidence indicates that alternative splicing (AS) plays a nonnegligible role in the formation and development of the tumor microenvironment (TME). However, the comprehensive analysis of the impact on prognostic AS events on immune-related perspectives in HCC is lacking but urgently needed.

Methods

The transcriptional data and clinical information of HCC patients were downloaded from TCGA (The Cancer Genome Atlas) database for calculating immune and stromal scores by ESTIMATE algorithm. We then divided patients into high/low score groups and explored their prognostic significance using Kaplan–Meier curves. Based on stromal and immune scores, differentially expressed AS events (DEASs) were screened and evaluated with functional enrichment analysis. Additionally, a risk score model was established by applying univariate and multivariate Cox regression analyses. Finally, gene set variation analysis (GSVA) was adopted to explore differences in biological behaviors between the high- and low-risk subgroups.

Results

A total of 370 HCC patients with complete and qualified corresponding data were included in the subsequent analysis. According to the results of ESTIMATE analysis, we observed that the high immune/stromal score group had a longer survival probability, which was significantly correlated with prognosis in HCC patients. In addition, 467 stromal/immune score-related DEASs were identified, and enrichment analysis revealed that DEASs were significantly enriched in pathways related to HCC tumorigenesis and the immune microenvironment. More importantly, the final prognostic signature containing 16 DEASs showed powerful predictive ability. Finally, GSVA demonstrated that activation of carcinogenic pathways and immune-related pathways in the high-risk group may lead to poor prognosis.

Conclusions

Collectively, these outcomes revealed prognostic AS events related to carcinogenesis and the immune microenvironment, which may yield new directions for HCC immunotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00294-3.

MicroRNA-497-5p Is Downregulated in Hepatocellular Carcinoma and Associated with Tumorigenesis and Poor Prognosis in Patients

Background

MicroRNAs (miRNAs) have been demonstrated to exhibit important regulatory roles in multiple malignancies, including hepatocellular carcinoma (HCC). hsa-miR-497-5p was reported to involve in cancer progression and poor prognosis in many kinds of tumors. However, the expression and its clinical significance of hsa-miR-497-5p in HCC remain unclear.

Methods

In the present study, we investigated the expression of hsa-miR-497-5p in HCC and analyzed the correction of clinical features with prognosis. The expression levels of hsa-miR-497-5p and potential target genes were analyzed in HCC and adjacent noncancerous tissues using The Cancer Genome Atlas (TCGA) database and Gene Expression Omnibus (GEO) datasets. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to analyze hsa-miR-497-5p levels in 328 HCC tissues and 30 paired adjacent noncancer tissues. Overall survival (OS) and progression-free survival (PFS) of patients with HCC were assessed using the Kaplan-Meier method and the log-rank test.

Results

The hsa-miR-497-5p expression levels were decreased, and its target genes ACTG1, CSNK1D, PPP1CC, and BIRC5 were upregulated in HCC tissues compared with normal tissues. Lower levels of hsa-miR-497-5p expression and higher levels of the four target genes were significantly associated with higher tumor diameter. Moreover, patients with lower hsa-miR-497-5p expression and higher target genes levels had shorter OS.

Conclusion

The expression levels of hsa-miR-497-5p may play an important regulatory role in HCC and are closely correlated with HCC progression and poor prognosis in patients. The hsa-miR-497-5p may be a specific therapeutic target for the treatment of HCC.

Long non-coding RNAs: the tentacles of chromatin remodeler complexes

Chromatin remodeler complexes regulate gene transcription, DNA replication and DNA repair by changing both nucleosome position and post-translational modifications. The chromatin remodeler complexes are categorized into four families: the SWI/SNF, INO80/SWR1, ISWI and CHD family. In this review, we describe the subunits of these chromatin remodeler complexes, in particular, the recently identified members of the ISWI family and novelties of the CHD family. Long non-coding (lnc) RNAs regulate gene expression through different epigenetic mechanisms, including interaction with chromatin remodelers. For example, interaction of lncBRM with BRM inhibits the SWI/SNF complex associated with a differentiated phenotype and favors assembly of a stem cell-related SWI/SNF complex. Today, over 50 lncRNAs have been shown to affect chromatin remodeler complexes and we here discuss the mechanisms involved.

Tumor-suppressive microRNA-551b-3p targets H6PD to inhibit gallbladder cancer progression

Gallbladder cancer (GBC) is a highly malignant cancer with poor prognosis. Extensive studies have reported the vital functionality of several microRNAs (miRNAs) in numerous human cancers, including GBC. Microarray analysis has identified the differentially expressed miR-551b-3p in GBC. Therefore, this study aims to validate the underlying mechanism by which miR-551b-3p participated in epithelial-mesenchymal transition (EMT), invasion and migration of GBCs. Bioinformatic analysis predicted the binding of miR-551b-3p to H6PD. We validated the reduced miR-551b-3p expression and increased H6PD expression in the GBC tissues and GBC cell lines. Artificial modulation of miR-551b-3p and H6PD (down- and upregulation) was conducted to explore their roles in EMT, invasive, and migratory abilities of GBCs, and the tumor-bearing mice were used to determine tumor growth. Overexpression of miR-551b-3p or silencing of H6PD was observed to suppress the expressions of N-cadherin and vimentin, and to promote the expression of E-cadherin, along with reduced invasive and migratory ability of GBCs. Mechanistically, miR-551b-3p could evidently target and inhibit the expression of H6PD. Moreover, in vivo experiments substantiated the tumor-inhibiting activities of miR-551b-3p in nude mice. Conjointly, our study suggests that overexpression of miR-551b-3p inhibited the EMT, migration, and invasion of GBCs by inhibiting the expression of H6PD, indicating that miR-551b-3p may serve as a potential target for future development of therapeutic strategies for GBC.

Exosomal noncoding RNAs in cholangiocarcinoma: Laboratory noise or hope?

Currently, extracellular vesicles and particularly exosomes have gained a lot of research interest due to their unique roles in several biological processes. Noncoding RNAs (microRNAs, long noncoding RNAs and circular RNAs) represent a class of functional RNA with distinct regulatory roles in tumorigenesis and cancer progression. Cholangiocarcinoma is a rare but highly aggressive type of malignancy that is very challenging to diagnose, especially in early stages; surgical resection still represents the sole potentially curative treatment option. Hence, there is an urgent need for the discovery of novel diagnostic and prognostic biomarkers. Hereby, we provide a comprehensive review of the most recent discoveries that focus on exosomal noncoding RNAs in cholangio-carcinoma with the aim to identify new molecular players that could be used as biomarkers and therapeutic targets.

Long non-coding RNAs in gastric cancer: New emerging biological functions and therapeutic implications

Gastric cancer (GC) is currently the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs), transcriptional products with more than 200 nucleotides, are not as well-characterized as protein-coding RNAs. Accumulating evidence has recently revealed that maladjustments of diverse lncRNAs may play key roles in multiple genetic and epigenetic phenomena in GC, affecting all aspects of cellular homeostasis, such as proliferation, migration, and stemness. However, the full extent of their functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets, future research should be focused on unravelling the intricate relationships between lncRNAs and GC that can be translated from bench to clinic. Here, we summarized the state-of-the-art advances in lncRNAs and their biological functions in GC, and we further discuss their potential diagnostic and therapeutic roles. We aim to shed light on the interrelationships between lncRNAs and GC with respect to their potential therapeutic applications. With better understanding of these relationships, the biological functions of lncRNAs in GC development will be exploitable, and promising new strategies developed for the prevention and treatment of GC.

Circular RNA is a popular molecule in tumors of the digestive system (Review)

Most tumors of the digestive system, including esophageal, gastric, liver and colorectal cancer, are malignant tumors that are associated with rates of high morbidity and mortality. The lack of effective methods for early diagnosis is an important cause of poor prognosis for these malignancies. Circular RNAs (circRNAs) belong to a family of endogenous, covalently closed non‑coding RNAs that are characterized as having no 5' cap structures or 3' poly‑A tails. Shortly following discovery, circRNAs were considered to be a product of mis‑splicing and have no significant biological function. However, in recent years, accumulating evidence is demonstrating that they serve key roles in tumorigenesis and have the potential to serve as diagnostic markers. The present article summarizes the biogenesis and function of circRNAs and reviews their role in seven common types of tumor of the digestive system whilst exploring their potential as tumor markers and the significant roles they can serve in the digestive system, in addition to providing a referencing point for future studies of digestive system malignancies.

Long Noncoding RNA OIP5-AS1 Promotes the Progression of Liver Hepatocellular Carcinoma via Regulating the hsa-miR-26a-3p/EPHA2 Axis

Numerous studies have suggested that dysregulated long noncoding RNAs (lncRNAs) contributed to the development and progression of many cancers. lncRNA OIP5 antisense RNA 1 (OIP5-AS1) has been reported to be increased in several cancers. However, the roles of OIP5-AS1 in liver hepatocellular carcinoma (LIHC) remain to be investigated. In this study, we demonstrated that OIP5-AS1 was upregulated in LIHC tissue specimens and its overexpression was associated with the poor survival of patients with LIHC. Furthermore, loss-of function experiments indicated that OIP5-AS1 promoted cell proliferation and inhibited cell apoptosis both in vitro and in vivo. Moreover, binding sites between OIP5-AS1 and hsa-miR-26a-3p as well as between hsa-miR-26a-3p and EPHA2 were confirmed by luciferase assays. Finally, a rescue assay was performed to prove the effect of the OIP5-AS1/hsa-miR-26a-3p/EPHA2 axis on LIHC cell biological behaviors. Based on all of the above findings, our results suggested that OIP5-AS1 promoted LIHC cell proliferation and invasion via regulating the hsa-miR-26a-3p/EPHA2 axis.

LncRNA OIP5-AS1 facilitates gastric cancer cell growth by targeting the miR-422a/ANO1 axis

OPA-interacting protein 5 antisense transcript 1 (OIP5-AS1) plays an important regulatory role in various types of cancers. However, the functional role and regulatory mechanisms of OIP5-AS1 in gastric cancer (GC) remain largely unknown. In this study, we found that the expression of OIP5-AS1 was increased in GC tissues compared with that in adjacent non-cancerous tissues, which was significantly associated with shorter overall survival time of patients. In addition, OIP5-AS1 expression was also increased in GC cell lines including NCI-N87, MKN-45, BGC-823 and SGC-7901, when compared with that in normal gastric epithelial cell line GES-1. Knockdown of OIP5-AS1 markedly suppressed the proliferation and colony formation activities of GC cells, induced G0/G1 arrest and apoptosis of GC cells in vitro, and restrained tumor growth in vivo. Mechanistically, OIP5-AS1 functions as an oncogenic competing endogenous RNA by binding to and sequestering miR-422a to elevate the expression of anoctamin-1. Our study first demonstrated that OIP5-AS1 is a critical and powerful regulator of GC pathogenesis and may represent a novel candidate target for GC therapy.

Plasma long noncoding RNAs PANDAR, FOXD2-AS1, and SMARCC2 as potential novel diagnostic biomarkers for gastric cancer

Background

Gastric cancer is still a common cancer worldwide. Investigation of potential plasma biomarkers for gastric cancer diagnosis is essential for prevention strategies and early intervention for gastric cancer-control planning.

Objectives

This study was aimed to explore the lncRNAs' promoter of CDKN1A antisense DNA-damage-activated RNA (PANDAR), FOXD2-AS1, and SMARCC2 as potential novel diagnostic biomarkers for gastric cancer.

Method

109 gastric cancer patients and 106 healthy controls were involved in this study. Plasma lncRNAs PANDAR, FOXD2-AS1, and SMARCC2 were detected by real-time PCR. Student's t-test, Mann-Whitney U test, and Chi-square test were used to verify the differences of clinical variables between two groups. Receiver operating characteristic curve (ROC) was used to evaluate the diagnostic value of every biomarker. Multivariable analysis of risk factors for gastric cancer was performed using logistic regression analysis.

Results

There were significant differences in age, gender, carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 153 between gastric cancer and healthy controls (P<0.05). Compared with healthy subjects, the levels of plasma lncRNAs PANDAR, FOXD2-AS1, and SMARCC2 were all significantly higher in gastric cancer patients (P<0.05). These lncRNAs were significantly associated with clinicopathological parameters of gastric cancer, like pathological differentiation, TNM stage, and/or lymph nodes metastasis, and/or invasion depth (P<0.05). The AUC for lncRNA PANDAR was 0.767, for FOXD2-AS1 was 0.700, for SMARCC2 was 0.748, and the AUC of the combinative diagnostic value of these three lncRNAs was 0.839. Adjusted by other variables, these lncRNAs' expressions were significantly associated with gastric cancer.

Conclusions

Plasma lncRNAs PANDAR, FOXD2-AS1, and SMARCC2 might be appropriate diagnostic biomarkers for gastric cancer.

Non-coding RNAs in regulating gastric cancer metastasis

Gastric cancer is one of the leading causes of cancer-related deaths worldwide, and mortality remains high, especially in East Asia. At present, the main method to diagnose gastric cancer is pathological biopsy. At the time of diagnosis, most patients have been diagnosed with advanced cancer and metastasis. The treatment of gastric cancer patients is mainly radical surgical resection and chemoradiotherapy, while patients with metastatic tumor have great challenges to radical surgery and are prone to drug resistance. Metastasis is an important factor affecting tumor development. In addition, evidence accumulated in the literature indicates that non-coding RNA plays a key role in tumor metastasis. This article reviews the role of ncRNAs in gastric cancer metastasis and discusses the regulatory mechanism in the development and treatment of gastric cancer.

MicroRNA-551b-3p inhibits tumour growth of human cholangiocarcinoma by targeting Cyclin D1

MicroRNAs (miRNAs) are powerful regulators in the tumorigenesis of cholangiocarcinoma (CCA). Previous studies report that miR‐551b‐3p acts as an oncogenic factor in ovarian cancer, but plays a tumour suppressive role in gastric cancer. However, the expression pattern and potential function of miR‐551b‐3p were still unclear in CCA. Therefore, this study aimed to explore the expression of miR‐551b‐3p and its role as well as molecular mechanism in CCA. Analysis of TCGA dataset suggested that miR‐551b‐3p was under‐expressed in CCA tissues compared to normal bile duct tissues. Furthermore, our data confirmed the decreased levels of miR‐551b‐3p in CCA samples and cell lines. Interestingly, TCGA data suggested that low miR‐551b‐3p level indicated reduced overall survival of CCA patients. Gain‐ and loss‐of‐function experiments found that miR‐551b‐3p inhibited the proliferation, G1‐S phase transition and induced apoptosis of CCA cells. In vivo experiments revealed that ectopic expression of miR‐551b‐3p inhibited tumour growth of CCA in mice. Further investigation demonstrated that miR‐551b‐3p directly bond to the 3′‐UTR of Cyclin D1 (CCND1) mRNA and negatively regulated the abundance of CCND1 in CCA cells. An inverse correlation between miR‐551b‐3p expression and the level of CCND1 mRNA was detected in CCA tissues from TCGA dataset. Notably, CCND1 knockdown showed similar effects to miR‐551b‐3p overexpression in HuCCT‐1 cells. CCND1 restoration rescued miR‐551b‐3p‐induced inhibition of proliferation, G1 phase arrest and apoptosis in HuCCT‐1 cells. In summary, miR‐551b‐3p inhibits the expression of CCND1 to suppress CCA cell proliferation and induce apoptosis, which may provide a theoretical basis for improving CCA treatment.

Long non-coding RNA-mediated regulation of signaling pathways in gastric cancer

Gastric cancer (GC) is one of the most common cancers globally. Because of the high frequency of tumor recurrence, or metastasis, after surgical resection, the prognosis of patients with GC is poor. Therefore, exploring the mechanisms underlying GC is of great importance. Recently, accumulating evidence has begun to show that dysregulated long non-coding RNAs (lncRNAs) participate in the progression of GC via several typical signaling pathways, such as the AKT and MAPK signaling pathways. Moreover, the interactions between lncRNAs and microRNAs appear to represent a novel mechanism in the pathogenesis of GC. This review provides a synopsis of the latest research relating to lncRNAs and associated signaling pathways in GC.