Non-coding RNAs and gastric cancer

piR-823 tale as emerging cancer-hallmark molecular marker in different cancer types: a step-toward ncRNA-precision

PIWI-interacting RNAs (piRNAs) have received a lot of attention for their functions in cancer research. This class of short non-coding RNAs (ncRNA) has roles in genomic stability, chromatin remodeling, messenger RNA (mRNA) integrity, and genome structure. We summarized the mechanisms underlying the biogenesis and regulatory molecular functions of piRNAs. Among all piRNAs studied in cancer, this review offers a comprehensive analysis of the emerging roles of piR-823 in various types of cancer, including colorectal, gastric, liver, breast, and renal cancers, as well as multiple myeloma. piR-823 has emerged as a crucial modulator of various cancer hallmarks through regulating multiple pathways. In the current review, we analyzed several databases and conducted an extensive literature search to explore the influence of piR-823 in carcinogenesis in addition to describing the potential application of piR-823 as prognostic and diagnostic markers as well as the therapeutic potential toward ncRNA precision.

Role of sRNAs protein molecules in extracellular vesicles derived from Lactobacillus plantarum rejuvenate against ultraviolet B-induced photoaging in human keratinocytes

Ultraviolet B (UVB) radiation accelerates the aging process of skin cells by triggering oxidative stress and inflammatory responses. The aim of this study was to investigate the mechanism of action of sRNAs and protein molecules in the regenerative extracellular vesicles of Lactobacillus plantarum against the UVB-induced photoaging process of human keratinocytes. The extracellular vesicles regenerated by Lactobacillus plantarum were isolated and purified to identify sRNAs and protein components. Human keratinocytes were treated with UVB radiation to simulate the photoaging model. The effects of different concentrations of vesicle extract on cell survival rate, oxidative stress index and inflammatory marker expression were evaluated in control group and treatment group. The results showed that the regenerated extracellular vesicles of L. plantarum significantly improved the survival rate of keratinocytes after UVB radiation, and delayed the aging process of skin cells by reducing oxidative stress and inhibiting inflammatory response.

A novel tRNA-derived fragment tRF-17-18VBY9M works as a potential diagnostic biomarker for gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most prevalent malignant tumors worldwide. The low effectiveness of common biomarkers for the detection of early GC makes it essential to seek new biomarkers to improve diagnostic efficacy. tsRNAs (transfer RNA-derived small RNAs) are related to the growth of malignant tumors. In this article, we focused on whether tsRNAs may be employed as biomarkers for GC.

METHODS

tRF-17-18VBY9M was screened in the tsRFun database as a research object. The methodological efficacy of tRF-17-18VBY9M was evaluated using Sanger sequencing, agarose gel electrophoresis assays, and gradient dilution. The χ2 test was applied to assess the interaction between tRF-17-18VBY9M expression and clinicopathologic characteristics. The receiver operating characteristic (ROC) curve was utilized to investigate the clinical efficiency of tRF-17-18VBY9M in GC.

RESULTS

The Chi-square test demonstrated that high-expressed tRF-17-18VBY9M was closely associated with the T stage, tumor node metastasis stage (TNM), lymph node metastasis, and neurological/vascular invasion. ROC curve analysis revealed that the diagnostic value of tRF-17-18VBY9M in GC was superior to carcinoembryonic antigen (CEA), carbohydrate antigen 199 (CA199), and carbohydrate antigen 724 (CA724).

CONCLUSION

tRF-17-18VBY9M is up-regulated in both GC sera and tissues. Differential tRF-17-18VBY9M expression distinguishes GC patients from healthy donors and gastritis patients, which suggests tRF-17-18VBY9M could act as a diagnostic biomarker in GC.

The prognostic, diagnostic, and therapeutic impact of Long noncoding RNAs in gastric cancer

Gastric cancer (GC), ranking as the third deadliest cancer globally, faces challenges of late diagnosis and limited treatment efficacy. Long non-coding RNAs (lncRNAs) emerge as valuable treasured targets for cancer prognosis, diagnosis, and therapy, given their high specificity, convenient non-invasive detection in body fluids, and crucial roles in diverse physiological and pathological processes. Research indicates the significant involvement of lncRNAs in various aspects of GC pathogenesis, including initiation, metastasis, and recurrence, underscoring their potential as novel diagnostic and prognostic biomarkers, as well as therapeutic targets for GC. Despite existing challenges in the clinical application of lncRNAs in GC, the evolving landscape of lncRNA molecular biology holds promise for advancing the survival and treatment outcomes of gastric cancer patients. This review provides insights into recent studies on lncRNAs in gastric cancer, elucidating their molecular mechanisms and exploring the potential clinical applications in GC.

Epigenetic modulation of cytokine expression in gastric cancer: influence on angiogenesis, metastasis and chemoresistance

Cytokines are proteins that act in the immune response and inflammation and have been associated with the development of some types of cancer, such as gastric cancer (GC). GC is a malignant neoplasm that ranks fifth in incidence and third in cancer-related mortality worldwide, making it a major public health issue. Recent studies have focused on the role these cytokines may play in GC associated with angiogenesis, metastasis, and chemoresistance, which are key factors that can affect carcinogenesis and tumor progression, quality, and patient survival. These inflammatory mediators can be regulated by epigenetic modifications such as DNA methylation, histone protein modification, and non-coding RNA, which results in the silencing or overexpression of key genes in GC, presenting different targets of action, either direct or mediated by modifications in key genes of cytokine-related signaling pathways. This review seeks insight into the relationship between cytokine-associated epigenetic regulation and its potential effects on the different stages of development and chemoresistance in GC.

A human stomach cell type transcriptome atlas

BACKGROUND

The identification of cell type-specific genes and their modification under different conditions is central to our understanding of human health and disease. The stomach, a hollow organ in the upper gastrointestinal tract, provides an acidic environment that contributes to microbial defence and facilitates the activity of secreted digestive enzymes to process food and nutrients into chyme. In contrast to other sections of the gastrointestinal tract, detailed descriptions of cell type gene enrichment profiles in the stomach are absent from the major single-cell sequencing-based atlases.

RESULTS

Here, we use an integrative correlation analysis method to predict human stomach cell type transcriptome signatures using unfractionated stomach RNAseq data from 359 individuals. We profile parietal, chief, gastric mucous, gastric enteroendocrine, mitotic, endothelial, fibroblast, macrophage, neutrophil, T-cell, and plasma cells, identifying over 1600 cell type-enriched genes.

CONCLUSIONS

We uncover the cell type expression profile of several non-coding genes strongly associated with the progression of gastric cancer and, using a sex-based subset analysis, uncover a panel of male-only chief cell-enriched genes. This study provides a roadmap to further understand human stomach biology.

MiR-1278 targets CALD1 and suppresses the progression of gastric cancer via the MAPK pathway

This study aimed to investigate the interaction between miR-1278 and Caldesmon (CALD1) in gastric cancer (GC) and the regulatory mechanism. In both GC cells and tissues, the levels of CALD1, miR-1278, migration-related markers (E-cadherin, N-cadherin, and Snail), and MAPK signaling pathway-related proteins were clarified using quantitative real-time PCR and western blotting analyses. The effects of miR-1278 and CALD1 on GC cell viability and migration were analyzed using CCK-8 and Transwell assays, respectively. The targeting effect of miR-1278 on CALD1 was investigated using bioinformatics prediction and a dual luciferase reporter assay. The effect of miR-1278 on tumor growth was estimated in vivo using a tumor xenograft assay. In GC, miR-1278 expression decreased, whereas CALD1 was highly expressed. Transfecting an miR-1278 mimic into cells inhibited the viability as well as migration of GC cells, and suppressed Ras, phosphorylated (p)-P38, and p-ERK1/2 protein levels. Moreover, miR-1278 targeted and negatively regulated CALD1 expression. CALD1 overexpression promoted GC cell survival and migration and activated the MAPK pathway. Treatment with an miR-1278 mimic partially rescued the changes caused by CALD1 overexpression. Overall, our study revealed that miR-1278 suppresses the malignant behavior of GC cells by targeting CALD1 and regulating the MAPK pathway.

Serum tRF-27-FDXXE6XRK45 as a Promising Biomarker for the Clinical Diagnosis in Gastric Cancer

Objective: Gastric cancer (GC) has high morbidity and mortality due to inefficient early screening. Therefore, we are searching for more sensitive and specific diagnostic markers for GC. tRNA-derived small RNAs are novel non-coding small RNAs with good abundance and stable presence in body fluids, which may play multiple biological regulatory roles. In this study, we aimed to find a potential biomarker with high accuracy in tRNA-derived small RNAs that can help diagnose GC. Methods: tRF-27-FDXXE6XRK45 was screened as a target molecule by high-throughput sequencing in three pairs of GC tissues. RNA quantitative reverse transcription PCR was conducted to detect the expression levels of tRF-27-FDXXE6XRK45. Agarose gel electrophoresis, Sanger sequencing, cytoplasmic and nuclear RNA isolation assays, gradient dilution experiments, and room temperature and repeated freeze-thaw experiments were used to assess the detection performance of tRF-27-FDXXE6XRK45. Using the chi-square test to analyze the correlation between tRF-27-FDXXE6XRK45 expression levels and clinicopathological parameters. In addition, receiver operating characteristic curves were used to evaluate the diagnostic value of tRF-27-FDXXE6XRK45 in GC. Results: tRF-27-FDXXE6XRK45 expression levels, significantly upregulated in tissues and sera of GC patients and decreased after radical GC surgery, were correlated with the degree of differentiation, depth of tumor infiltration, TNM stage, lymph node metastasis, and nerve/vascular invasion. In comparison with current GC diagnostic markers, tRF-27-FDXXE6XRK45 displayed better efficacy. Conclusions: tRF-27-FDXXE6XRK45, with high diagnostic efficacy, can distinguish GC patients from gastritis patients and healthy donors, suggesting that tRF-27-FDXXE6XRK45 may be a promising candidate as a diagnostic marker for GC.

A comprehensive insight into the correlation between ncRNAs and the Wnt/β-catenin signalling pathway in gastric cancer pathogenesis

During the past decades, gastric cancer (GC) has emerged as one of the most frequent malignancies with a growing rate of prevalence around the world. Despite considerable advances in therapeutic methods, the prognosis and management of patients with gastric cancer (GC) continue to be poor. As one of the candidate molecular targets in the treatment of many types of cancer, the Wnt/β-catenin pathway includes a family of proteins that have important functions in adult tissue homeostasis and embryonic development. The aberrant regulation of Wnt/β-catenin signaling is strongly correlated with the initiation and development of numerous cancers, including GC. Therefore, Wnt/β-catenin signaling has been identified as one of the main targets for extending therapeutic approaches for GC patients. Non-coding RNAs (ncRNAs), including microRNAs and long ncRNAs, are important components of epigenetic mechanisms in gene regulation. They play vital roles in various molecular and cellular processes and regulate many signaling pathways, such as Wnt/β-catenin pathways. Insights into these regulatory molecules involved in GC development may lead to the identification of potential targets for overcoming the limitations of current therapeutic approaches. Consequently, this review aimed to provide a comprehensive overview of ncRNAs interactions involved in Wnt/β-catenin pathway function in GC with diagnostic and therapeutic perspectives. Video Abstract.

The Human Gastric Juice: A Promising Source for Gastric Cancer Biomarkers

Gastric cancer (GC) is a major public health problem worldwide, with high mortality rates due to late diagnosis and limited treatment options. Biomarker research is essential to improve the early detection of GC. Technological advances and research methodologies have improved diagnostic tools, identifying several potential biomarkers for GC, including microRNA, DNA methylation markers, and protein-based biomarkers. Although most studies have focused on identifying biomarkers in biofluids, the low specificity of these markers has limited their use in clinical practice. This is because many cancers share similar alterations and biomarkers, so obtaining them from the site of disease origin could yield more specific results. As a result, recent research efforts have shifted towards exploring gastric juice (GJ) as an alternative source for biomarker identification. Since GJ is a waste product during a gastroscopic examination, it could provide a "liquid biopsy" enriched with disease-specific biomarkers generated directly at the damaged site. Furthermore, as it contains secretions from the stomach lining, it could reflect changes associated with the developmental stage of GC. This narrative review describes some potential biomarkers for gastric cancer screening identified in gastric juice.

Integrative analysis of small non-coding RNAs predicts a piRNA/miRNA-CCND1/BRAF/HRH1/ATXN3 regulatory circuit that drives oncogenesis in glioblastoma

The high-grade astrocytoma, glioblastoma multiforme (GBM), is the most common primary tumour of the brain, known for being aggressive and developing drug resistance. The non-coding RNAs (ncRNAs), such as microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs), have critical functions in tumorigenesis and cancer drug resistance. Hence, we profiled miRNAs, piRNAs, and genes in U-87 MG GBM cells by next-generation sequencing and performed target prediction, pathway enrichment, protein-protein interaction, co-expression studies, and qRT-PCR validations to predict their possible roles in the malignancy. The study identified 335 miRNAs, 665 piRNAs, and 4286 genes differentially expressed (DE) in GBM. Among them 128 DE genes (DEGs) were targeted by both miRNAs and piRNAs, while 1817 and 192 were targeted solely by miRNAs or piRNAs, respectively. Interestingly, all the DEG targets enriched in cancer processes were overexpressed in GBM. Among these, BRAF was solely targeted by two piRNAs and this was found to be co-expressed with 19 sole targets of 5 miRNAs, including CCND1, and both were found to regulate cell proliferation in cancer. We conjectured that upregulated HRH1 and ATXN3 were targeted by both piRNAs and miRNAs, and along with BRAF and CCND1 might induce cell proliferation in GBM through G-protein-coupled receptor or Akt signalling pathways due to downregulation of the respective targeting small RNAs. These targets were also linked to the progression and overall survival of GBM patients, suggesting that they could be used as biomarkers. Overall, this study has identified a few novel ncRNA targets, which might aid in a better understanding of GBM pathogenesis.

A comprehensive review of the role of lncRNAs in gastric cancer (GC) pathogenesis, immune regulation, and their clinical applications

Gastric cancer (GC) is the fifth most common malignant tumor and the third leading cause of cancer-related deaths worldwide. Although numerous studies have been conducted on advanced GC, the molecular mechanisms behind it remain obscure. Long non-coding RNAs (lncRNAs) are a family of RNA transcripts capable of regulating target genes at transcriptional, post-transcriptional, and translational stages. They do this by modifying mRNAs, miRNAs, and proteins. These RNAs are critical regulators of many biological processes, including gene epigenetics, transcription, and post-transcriptional levels. This article highlights recent results on lncRNAs involved in drug resistance, proliferation, migration, angiogenesis, apoptosis, autophagy, and immune response in GC. The potential clinical implications of lncRNAs as biomarkers and therapeutic targets in GC are also discussed.

miRNA-223-3p regulates ECT2 to promote proliferation, invasion, and metastasis of gastric cancer through the Wnt/β-catenin signaling pathway

PURPOSE

Expression of the guanine nucleotide exchange factor epithelial cell transforming 2 (ECT2) is elevated in gastric cancer (GC) but its biological function in GC is poorly understood. MicroRNAs (miRNAs) have great potential as therapeutic targets for GC through their ability to modulate gene expression. In the present study, we sought to identify potential miRNA-mRNA-protein regulatory pathways that might control ECT2 expression and function in GC.

METHODS

ECT2 expression was examined in clinical GC specimens by immunohistochemical staining, and protein levels were correlated with clinicopathological features and prognosis. TargetScan was used to identify potential ECT2 mRNA-complementary miRNAs, and the roles of ECT2 and miRNA-223-3p (miR-223-3p) in GC cell biology and signaling pathway activation were examined by targeted knockdown (KD) or overexpression (OE) of ECT2 and miR-223-3p in GC cell lines. A murine GC xenograft model was developed to explore the impact of ECT2 OE on tumor growth in vivo.

RESULTS

ECT2 expression was significantly elevated in GC specimens compared with normal gastric tissues and the level correlated positively with depth of invasion, ulceration, vascular tumor thrombus, neural invasion, and lymph node metastasis (p < 0.05). ECT2 was an independent prognostic factor for overall survival of GC patients (high ECT2 expression v.s. low ECT2 expression: χ² = 29.831, p < 0.001). ECT2 KD or miR-223-3p OE markedly suppressed the proliferation, migration, and invasion of GC cells in vitro, whereas ECT2 OE had the opposite effects. ECT2 OE also promoted the growth of GC tumors in vivo. Tumor expression of Wnt2, β-catenin, and several downstream target proteins in GC cells were decreased by ECT2 KD or miR-223-3p OE but increased by ECT2 OE.

CONCLUSIONS

miR-223-3p regulates ECT2 expression to promote tumorigenic behavior of GC via activation of the Wnt/β-catenin signaling pathway, suggesting that ECT2 and miR-223-3p as potential therapeutic targets for GC.

Genome-wide profiling of dysregulated piRNAs and their target genes implicated in oncogenicity of Tongue Squamous Cell Carcinoma

PIWI-interacting RNAs (piRNAs) are single-stranded, 23-36 nucleotide long RNAs that regulate gene expression in the germline but are also detected in some cancers. However, there are no reports yet on piRNA expression in tongue squamous cell carcinoma (TSCC), the most common oral cancer (80-90% percent of all oral cancers). We performed small RNA and whole transcriptome sequencing in H357 tongue cancer and HOK cells (GEO database accession numbers: GSE196674 and GSE196688). We also examined nine published sets of gene expression array data of TSCC tissues from the GEO database to decode piRNAs and their putative targets that may be involved in tumorigenesis. We identified a pool of 16058 and 25677 piRNAs in H357 and HOK, respectively, among which 406 are differentially expressed. We also found that 2094 protein-coding genes are differentially expressed in either TSCC tissues or cell lines. We performed target predictions for these piRNA, pathway and disease function (DF) analyses, as well as qRT-PCR validation of piRNA-target pairs. These experiments revealed one up-regulated (FDFT1) and four down-regulated (OGA, BDH1, TAT, HYAL4) target genes that are enriched in 11 canonical pathways (CPs), with postulated roles in the initiation and progression of TSCC. Downregulation of piR-33422 is predicted to upregulate the FDFT1 gene, which encodes a mevalonate/cholesterol-pathway related farnesyl-diphosphate farnesyltransferase. The FDFT1 appears to be involved in the largest number of oncogenesis-related processes and is interacting with statins, which is a classical cancer drug. This study provides the first evidence of the piRNome of TSCC, which could be investigated further to decode piRNA-mediated gene regulations in malignancy and potential drug targets, such as FDFT1.

Emerging roles of PIWI-interacting RNAs (piRNAs) and PIWI proteins in head and neck cancer and their potential clinical implications

Head and neck squamous cell carcinoma (HNSCC) are among the well-known neoplasms originating in the oral cavity, pharynx, and larynx. Despite advancements in chemotherapy, radiotherapy, and surgery, the survival rates of the patients are low, which has posed a major therapeutic challenge. A growing number of non-coding RNAs (ncRNAs), for instance, microRNAs, have been identified whose abnormal expression patterns have been implicated in HNSCC. However, more recently, several seminal research has shown that piwi-interacting RNAs (piRNAs), a promising and young class of small ncRNA, are linked to the emergence and progression of cancer. They can regulate transposable elements (TE) and gene expression through multiple mechanisms, making them potentially more powerful regulators than miRNAs. Hence, they can be more promising ncRNAs candidates for cancer therapeutic intervention. Here, we surveyed the roles and clinical implications of piRNAs and their PIWI proteins partners in tumorigenesis and associated molecular processes of cancer, with a particular focus on HNSCC, to offer a new avenue for diagnosis, prognosis, and therapeutic interventions for the malignancy, improving patient's outcomes.

Evaluation of serum tRF-23-Q99P9P9NDD as a potential biomarker for the clinical diagnosis of gastric cancer

Background

Gastric cancer (GC) is one of the diseases that endanger human health with high morbidity and mortality. The positive rates of traditional biomarkers in the diagnosis of GC are low, so it is necessary to find biomarkers with high sensitivity to increase the detection rate. tRNA-derived small RNAs (tsRNAs) are novel small non-coding RNAs with specific biological functions and aberrant expression in cancer. In this study, we focused on the potential of tRNA-derived small RNAs as GC biomarkers.

Methods

The differentially expressed tsRNAs in three pairs of GC tissues were screened with high-throughput sequencing and verified using the TCGA database and Quantitative real-time PCR. The methodological evaluation of tRF-23-Q99P9P9NDD was verified by agarose gel electrophoresis, RIN evaluation, and Sanger sequencing. The Chi-square test was used to evaluate the relationship between the tRF-23-Q99P9P9NDD expression and clinicopathological parameters. Kaplan–Meier survival analysis was used to evaluate the effect of the tRF-23-Q99P9P9NDD expression on survival. Additionally, the receiver operating characteristic curve (ROC) was used to evaluate the diagnostic efficacy of tRF-23-Q99P9P9NDD in GC.

Results

Differential expression of serum tRF-23-Q99P9P9NDD could distinguish GC patients from gastritis patients and healthy donors. Chi-square test showed that high expression of tRF-23-Q99P9P9NDD was significantly associated with T stage, lymph node metastasis, TNM stage, and nerve/vascular invasion. Kaplan–Meier curve showed that patients with high expression of tRF-23-Q99P9P9NDD had a lower survival rate than patients with low expression of this biomarker. ROC analysis showed that, compared with conventional biomarkers, the efficacy of tRF-23-Q99P9P9NDD was higher, which was improved by the combination of biomarkers, and even in the early stages. Finally, we preliminarily predicted the downstream of tRF-23-Q99P9P9NDD in GC cells.

Conclusions

The expression of tRF-23-Q99P9P9NDD in GC serum can identify GC patients, and it has higher efficacy than conventional biomarkers even in the early stages. Furthermore, tRF-23-Q99P9P9NDD can monitor the postoperative conditions of GC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00491-8.

The clinical value of miRNA-21 in cervical cancer: A comprehensive investigation based on microarray datasets

Previous work has demonstrated that the expression of microRNA-21 (miR-21) is implicated in cervical cancer (CC). However, little is known regarding its associations with clinical parameters. We first conducted a meta-analysis using data from Gene Expression Omnibus (GEO) microarrays and The Cancer Genome Atlas (TCGA). Then, enrichment analysis and hub gene screening were performed by bioinformatic methods. Finally, the role of the screened target genes in CC was explored. According to the meta-analysis, the expression of miR-21 in cancer tissues was higher than in adjacent nontumor tissues (P < 0.05). In addition, 46 genes were predicted as potential targets of miR-21. After enrichment analyses, it was detected that these genes were enriched in various cancer pathways, including the phosphatidylinositol signaling system and mammalian target of rapamycin (mTOR) signaling pathway. In this study, bioinformatic tools and meta-analysis validated that miR-21 may function as a highly sensitive and specific marker for the diagnosis of CC, which may provide a novel approach to the diagnosis and treatment of CC.

Identification and Characterization of Polymorphisms in piRNA Regions

piRNAs are a class of noncoding RNAs that perform functions in epigenetic regulation and silencing of transposable elements, a mechanism conserved among most mammals. At present, there are more than 30,000 known piRNAs in humans, of which more than 80% are derived from intergenic regions, and approximately 20% are derived from the introns and exons of pre-mRNAs. It was observed that the expression of the piRNA profile is specific in several organs, suggesting that they play functional roles in different tissues. In addition, some studies suggest that changes in regions that encode piRNAs may have an impact on their function. To evaluate the conservation of these regions and explore the existence of a seed region, SNP and INDEL variant rates were investigated in several genomic regions and compared to piRNA region variant rates. Thus, data analysis, data collection, cleaning, treatment, and exploration were implemented using the R programming language with the help of the RStudio platform. We found that piRNA regions are highly conserved after considering INDELs and do not seem to present an identifiable seed region after considering SNPs and INDEL variants. These findings may contribute to future studies attempting to determine how polymorphisms in piRNA regions can impact diseases.

LncRNA GACAT3: A Promising Biomarker and Therapeutic Target in Human Cancers

Long non-coding RNAs (lncRNAs) are a class of functional RNA molecules that do not encode proteins and are composed of more than 200 nucleotides. LncRNAs play important roles in epigenetic and gene expression regulation. The oncogenic lncRNA GACAT3 was recently discovered to be dysregulated in many tumors. Aberrant expression of GACAT3 contributes to clinical characteristics and regulates multiple oncogenic processes. The association of GACAT3 with a variety of tumors makes it a promising biomarker for diagnosis, prognosis, and targeted therapy. In this review, we integrate the current understanding of the pathological features, biological functions, and molecular mechanisms of GACAT3 in cancer. Additionally, we provide insight into the utility of GACAT3 as an effective diagnostic and prognostic marker for specific tumors, which offers novel opportunities for targeted therapeutic intervention.

CircRNAs as Potential Blood Biomarkers and Key Elements in Regulatory Networks in Gastric Cancer

Gastric cancer (GC) is the fifth most common type of cancer and the third leading cause of cancer death in the world. It is a disease that encompasses a variety of molecular alterations, including in non-coding RNAs such as circular RNAs (circRNAs). In the present study, we investigated hsa_circ_0000211, hsa_circ_0000284, hsa_circ_0000524, hsa_circ_0001136 and hsa_circ_0004771 expression profiles using RT-qPCR in 71 gastric tissue samples from GC patients (tumor and tumor-adjacent samples) and volunteers without cancer. In order to investigate the suitability of circRNAs as minimally invasive biomarkers, we also evaluated their expression profile through RT-qPCR in peripheral blood samples from patients with and without GC (n = 41). We also investigated the predicted interactions between circRNA-miRNA-mRNA and circRNA-RBP using the KEGG and Reactome databases. Overall, our results showed that hsa_circ_0000211, hsa_circ_0000284 and hsa_circ_0004771 presented equivalent expression profiles when analyzed by different methods (RNA-Seq and RT-qPCR) and different types of samples (tissue and blood). Further, functional enrichment results identified important signaling pathways related to GC. Thus, our data support the consideration of circRNAs as new, minimally invasive biomarkers capable of aiding in the diagnosis of GC and with great potential to be applied in clinical practice.

Upregulation of miR-886 indicates poor prognosis and promotes tumour progression of prostate cancer

Prostate cancer is a heterogeneous disease with high incidence and mortality. The functional role of miR-886 has been reported in various cancers and its dysregulation in prostate cancer was also found. Whether miR-886 was involved in the development of prostate cancer remains unclear, which was explored. miR-886 was evaluated in prostate cancer by RT-qPCR, and its clinical value was also assessed. Additionally, the role of miR-886 in prostate cancer cells was assessed by MTT and transwell assay. miR-886 was upregulated and was associated with the Gleason score and TNM stage of prostate cancer patients. miR-886 could predict the poor survival of patients. Moreover, miR-886 was a tumour promoter, of which the upregulation significantly promoted major cellular processes of prostate cancer. miR-886 mediated the disease development and predicted the clinical outcomes of patients. The knockdown of miR-886 inhibits cellular processes of prostate cancer, which provides a novel therapeutic target.

Lactate induces aberration in the miR-30a-DBF4 axis to promote the development of gastric cancer and weakens the sensitivity to 5-Fu

Background

Gastric cancer (GC) is one of the most common malignancies, molecular mechanism of which is still not clear. Aberrant expression of tumor-associated genes is the major cause of tumorigenesis. DBF4 is an important factor in cancers, although there is yet no report on its function and molecular mechanism in GC.

Methods

The expression of DBF4 in tumor tissues or cells of GC was detected by qRT-PCR and western blotting. Gastric cancer cell line MGC-803 and AGS were transfected with DBF4 siRNA or overexpression vector to detect the function of DBF4 in proliferation, migration and the sensitivity to 5-Fu with CCK-8 assay, colony formation assay, transwell assay, and wound healing assay. miR-30a was found to be the regulator of DBF4 by online bioinformatics software and confirmed with qRT-PCR, western blot and dual-luciferase reporter assays.

Results

In our study, increased expression of DBF4 in GC tissues was first identified through The Cancer Genome Atlas (TCGA) and later confirmed using specimens from GC patients. Furthermore, functional experiments were applied to demonstrate that DBF4 promotes cell proliferation and migration in GC cell lines, moreover weakens the sensitivity of MGC803 and AGS cells to 5-Fu. We further demonstrated that miR-30a showed significantly lower expression in GC cells and inhibited the expression of DBF4 through 3ʹ-UTR suppression. Furthermore, rescue experiments revealed that the miR-30a-DBF4 axis regulated the GC cell proliferation, migration and the sensitivity to 5-Fu. The important composition in tumor microenvironment, lactate, may be the primary factor that suppressed miR-30a to strengthen the expression of DBF4.

Conclusions

Taken together, our study was the first to identify DBF4 as a regulator of cell proliferation and migration in GC. Furthermore, our study identified the lactate-miR-30a-DBF4 axis as a crucial regulator of tumor progression and the tumor sensitivity to 5-Fu, which maybe serve useful for the development of novel therapeutic targets.

lncRNA TINCR attenuates the proliferation and invasion, and enhances the apoptosis of cutaneous malignant melanoma cells by regulating the miR‑424‑5p/LATS1 axis

Cutaneous malignant melanoma (CMM) is responsible for ≥1/2 of skin cancer‑related mortalities. The aberrant expression of long non‑coding RNAs (lncRNAs) has been associated with the development of CMM. However, to the best of our knowledge, the role of the lncRNA TINCR ubiquitin domain containing (TINCR) in CMM has not been previously investigated, and thus, the current study aimed to evaluate this in vitro and in vivo. Reverse transcription‑quantitative PCR (RT‑qPCR) was used to analyze microRNA (miR)‑424‑5p expression, and RT‑qPCR and western blotting were used to measure TINCR, large tumor suppressor kinase 1 (LATS1), cellular communication network factor 2 (CTGF), cellular communication network factor 1 (CCN1) and AXL receptor tyrosine kinase (AXL) mRNA and protein expression levels, respectively. Cell Counting Kit‑8, flow cytometry and Transwell assays were used to detect the proliferation, apoptosis and invasion of CMM cell lines, respectively. The binding sites between TINCR and miR‑424‑5p were predicted using the miRDB database. A dual luciferase reporter assay and RT‑qPCR were used to identify the relationship between TINCR and miR‑424‑5p in CMM cell lines. The bioinformatics analysis revealed that TINCR was one of the most significantly downregulated lncRNAs in CMM, and advanced stage CMM tissues showed the greatest decrease in TINCR expression. Moreover, in the collected CMM tissues and tested cell lines of the current study, TINCR expression was found to be downregulated compared with the respective controls. Notably, TINCR overexpression inhibited the expression levels of CTGF, CCN1 and AXL, decreased the proliferation and invasion, and induced the apoptosis of CMM cell lines. In addition, a mutual binding association was identified between miR‑424‑5p and TINCR in CMM cells. LATS1, a target of miR‑424‑5p, was found to be positively regulated by TINCR. TINCR activated Hippo signaling and repressed the activity of Yes 1 associated transcriptional regulator by regulating LATS1 expression, while LATS1 knockdown reversed the effect of TINCR overexpression on CMM cells. Collectively, the findings of the present study suggested that TINCR may attenuate the progression of CMM by regulating the miR‑424‑5p/LATS1 signaling axis. These results indicated that TINCR may play a tumor suppressive role in CMM.

H19 Overexpression Improved Efficacy of Mesenchymal Stem Cells in Ulcerative Colitis by Modulating the miR-141/ICAM-1 and miR-139/CXCR4 Axes

Overexpression of C-X-C motif chemokine receptor 4 (CXCR4) and intercellular cell adhesion molecule-1 (ICAM-1) may promote homing of mesenchymal stem cells (MSC). In this study, we treated ulcerative colitis animals with MSC preconditioned with or without H19 and compared the therapeutic effect of MSC and MSC-H19. We evaluated the regulatory relationship of H19 vs. miR-141/miR-139 and miR-141/miR-139 vs. ICAM-1/CXCR4. We established an ulcerative colitis mouse model to assess the effect of MSC and MSC-H19. H19 was found to bind to miR-141 and miR-139. The activity of H19 was strongly decreased in cells c-transfected with miR-141/miR-139 and WT H19. ICAM-1 was confirmed to be targeted by miR-141 and CXCR4 was targeted by miR-139. The H19 expression showed a negative regulatory relationship with the miR-141 and miR-139 expression but a positive regulatory relationship with the ICAM-1 and CXCR4 expression. In summary, the overexpression of H19 in MSC downregulated miR-139 and miR-141, thus increasing the activity of their targets ICAM-1 and CXCR4, respectively, to exhibit therapeutic effects in ulcerative colitis.

Piwi-interacting RNA-651 promotes cell proliferation and migration and inhibits apoptosis in breast cancer by facilitating DNMT1-mediated PTEN promoter methylation

Piwi-interacting RNAs (piRNAs/piRs) are small non-coding RNAs that play important roles in stablizing genome through silencing transposable genetic elements. The piR-651 was reported to be dysregulated in several human solid cancer tissues, such as gastric and lung cancers. However, the role of piRNA-651 in carcinogenesis of breast cancer has not been defined. We found that piR-651 was highly expressed in breast cancer tissues and cell lines. Overexpression of piR-651 facilitated cell proliferation and invasion, restrained cell apoptosis and the percentage of arrested cells in G0/G1 phase, accompanied by upregulated expression of oncogenes (MDM2, CDK4 and Cyclin D1), whereas piR-651 downregulation showed the opposite effects. Additionally, piR-651 could promote phosphatase and tensin homolog (PTEN) methylation and its downregulated expression by recruiting DNA methyltransferase 1 (DNMT1) to the PTEN promoter region through complex formation with PIWIL2. PTEN overexpression reversed the effects of upregulated piR-651 on cell functions. This study reveals that piR-651 promotes proliferation and migration and induces apoptosis of breast cancer cells by facilitating DNMT1-mediated PTEN promoter methylation, which may provide a potential therapeutic mechanism for breast cancer.

Dysregulation of lncRNA in Helicobacter pylori-Infected Gastric Cancer Cells

Helicobacter pylori (H. pylori) infection is the most common cause of gastric cancer (GC). This microorganism is genetically diverse; GC is caused by several genetic deregulations in addition to environmental factors and bacterial virulence factors. lncRNAs (long noncoding RNAs) are significant biological macromolecules in GC, have specific functions in diseases, and could be therapeutic targets. Altered lncRNAs can lead to the abnormal expression of adjacent protein-coding genes, which may be important in cancer development. Their mechanisms have not been well understood, so we are going to investigate the risk of GC in a population with both high lncRNA and H. pylori infection.

Identification and validation of key non-coding RNAs and mRNAs using co-expression network analysis in pre-eclampsia

Pre-eclampsia (PE) is a common complication of pregnancy, associated with maternal and fetal morbidity and mortality. In this study, we aimed to explore important long non-coding RNAs (lncRNAs) and their possible mechanisms in PE.GSE60438 expression profile including 25 PE samples and 23 normal samples were obtained from gene expression omnibus (GEO) database. After normalization with betaqn package in R, differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs) were identified using the limma package. Gene Ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway were analyzed using DAVID 6.7 and GSEA 3.0. LncRNAs-mRNAs coexpression was implemented using weighted gene co-expression network analysis (WGCNA). MicroRNAs linked with these DElncRNAs and DEmRNAs were predicted and a competitive endogenous RNA (ceRNA) network was built.A total of 53 DElncRNAs and 301 DEmRNAs were identified between control and PE samples. These DEmRNAs were enriched into pathways such as protein digestion and absorption, osteoclast differentiation. WGCNA constructed a lncRNA-mRNA coexpression network, among which SUMO1P3, NACAP1, NCF1C, ANXA2P1, GTF2IP1, NAPSB, OR7E37P were hub genes. ceRNA network was constructed together with microRNAs (miRNAs), and functional analysis indicated cellular membrane and sugar binding were involved in PE progression. Five lncRNAsANXA2P1, GTF2IP1, NACAP1, NCF1C and OR7E37P were successfully validated in our clinical specimens.The DElncRNAs, including ANXA2P1, GTF2IP1, NACAP1, NCF1C and OR7E37P might play important roles in PE. However, the exact mechanism of these lncRNAs in prediction and diagnosis of PE should be further explored.

MiR-19a/miR-96-mediated low expression of KIF26A suppresses metastasis by regulating FAK pathway in gastric cancer

Gastric cancer (GC) is one of the most common malignant neoplasms. Invasion and metastasis are the main causes of GC-related deaths. Recently, kinesins were discovered to be involved in tumor development. The aim of this study was to elucidate the roles of kinesin superfamily protein 26A (KIF26A) in GC and its underlying molecular mechanism in regulating tumor invasion and metastasis. Using real-time quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC), we showed that KIF26A expression was lower in GC tissues without lymph node metastasis (LNM) than in nontumorous gastric mucosa, and even lower in GC tissues with LNM than in GC tissues without LNM. Functional experiments showed that KIF26A inhibited migration and invasion of GC cells. We further identified focal-adhesion kinase (FAK), phosphatidylinositol 3-kinase regulatory subunit alpha (PI3KR1), VAV3, Rac1 and p21-activated kinase 2, and β-PAK (PAK3) as downstream effectors of KIF26A in the focal-adhesion pathway, and we found that KIF26A could regulate FAK mRNA expression through inhibiting c-MYC by MAPK pathway. c-MYC could bind to the promoter of FAK and activate FAK transcription. Moreover, we found that KIF26A-mediated inactivation of the focal-adhesion pathway could reduce the occurrence of the epithelial-to-mesenchymal transition (EMT) by increasing expression of E-cadherin and reducing that of Snail. Luciferase assays and Western blotting revealed that miR-19a and miR-96 negatively regulate KIF26A. Finally, we found that decreased expression of KIF26A has been positively correlated with histological differentiation, Lauren classification, LNM, distal metastasis, and clinical stage, as well as poor survival in patients with GC. These data indicate that KIF26A could inhibit GC migration and invasion by regulating the focal-adhesion pathway and repressing the occurrence of EMT.

Long intergenic non-coding RNA (lincRNA)-01317 suppresses human gastric cancer growth by inhibiting migration and invasion of cancer cells

Long intergenic noncoding RNAs (lincRNAs) are strongly associated with several kinds of cancer, including gastric cancer. Here, we found significantly decreased lincRNA-01317 levels in cancer tissue compared with paracancer tissue of patients with gastric cancer, and lincRNA-01317 expression levels positively correlated with clinical survival rate. Furthermore, using a gastric cancer cell line and a xenograft mouse model, we found that transfection of a gastric cancer cell line with lincRNA-01317 significantly inhibited the proliferation, migration, and invasion of gastric cancer cells. Finally, we demonstrated that lincRNA-01317 may target KCNQ1, as KCNQ1 was downregulated after transfection of cells with lincRNA-01317. This study aimed to assess lincRNA-01317 as a potential therapeutic target to treat cancers.

Downregulation of long non‑coding RNA GACAT1 suppresses proliferation and induces apoptosis of NSCLC cells by sponging microRNA‑422a

Increasing evidence has demonstrated the important roles of long non‑coding (lnc) RNA in non‑small cell lung cancer (NSCLC). lncRNA gastric cancer‑associated transcript 1 (GACAT1) has been reported to play an oncogenic role in different types of cancer; however, the function of GACAT1 in NSCLC remains unclear. The present study found that GACAT1 was overexpressed in NSCLC tissues and was associated with poor outcomes in patients with NSCLC. Functional experiments revealed that GACAT1 downregulation inhibited proliferation, induced apoptosis and cell cycle arrest of 2 NSCLC cell lines. GACAT1 was found to target microRNA(miR)‑422a mechanically and negatively regulated miR‑422a expression. Reduced expression of miR‑422a in NSCLC tissues was inversely correlated with that of GACAT1. Furthermore, YY1 transcription factor (YY1) was identified as a downstream miR‑422a target. Reduced expression of GACAT1 inactivated YY1 by sponging miR‑422a in NSCLC cells. YY1 reintroduction reversed the reduced proliferation of NSCLC cells via GACAT1 knockdown. Taken together, these results revealed the novel role of the GACAT1/miR‑422a pathway in the progression of NSCLC cell lines, providing a possible therapeutic strategy for NSCLC treatment.

Long Noncoding RNAs: New Regulators of Resistance to Systemic Therapies for Gastric Cancer

Gastric cancer (GC) is the second leading cause of cancer mortality and the fourth most commonly diagnosed malignant disease, with approximately 951,000 new cases diagnosed and approximately 723,000 cases of mortality each year. The highest mortality rate of GC is in East Asia, and the lowest is in North America. A large number of studies have demonstrated that GC patients are characterized by higher morbidity, metastasis rates, and mortality and lower early diagnosis rates, radical resection rates, and 5-year survival rates. All cases of GC can be divided into two important stages, namely, early- and advanced-stage GC, and the stage mainly determines the treatment strategy for and the therapeutic effect in GC patients. Patients with early-stage GC undergo radical surgery followed by chemotherapy, and the 5-year survival rate can be as high as 90%. However, patients with advanced-stage GC cannot undergo radical surgery because they are at risk for metastasis; therefore, they can choose only radiotherapy or chemotherapy and have a poor prognosis. Based on the lack of specific clinical manifestations and detection methods, most GC patients (>70%) are diagnosed in the advanced stage; therefore, continued efforts toward developing treatments have been focused on advanced-stage GC patients and include molecular targeted therapy, immunotherapy, and small molecular therapy. Nevertheless, in recent years, accumulating evidence has indicated that small molecules, especially long noncoding RNAs (lncRNAs), are involved in the occurrence, development, and progression of GC, and their abundantly dysregulated expression has been identified in GC tissues and cell lines. Therefore, lncRNAs are considered easily detectable molecules and ideal biomarkers or target-specific agents for the future diagnosis or treatment of GC. In this review, we primarily discuss the status of GC, the role of lncRNAs in GC, and the emerging systemic treatments for GC.

LINC00968 can inhibit the progression of lung adenocarcinoma through the miR-21-5p/SMAD7 signal axis

Background: Long non-coding RNAs (LncRNAs) have been associated with several types of cancer. However, little is known about their role in lung adenocarcinoma (LUAD).

Results: LINC00968 was significantly differentially expressed in LUAD tissues. Downregulated LINC00968 was associated with clinicopathological features of LUAD. LINC00968 inhibited cell growth and metastasis by regulating the Hippo signaling pathway We demonstrated that LINC00968 acts as a ceRNA to consume miR-21-5p, enhancing the accumulation of SMAD7, a miR-21-5p target.

Conclusions: LINC00968 limits LUAD progression via the miR-21-5p/SMAD7 axis and may serve as a prognostic biomarker and therapeutic target for LUAD.

Methods: We conducted comprehensive data mining on LINC00968 based on the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) database. The expression of LINC00968 in LUAD cells was determined using in situ hybridization. We detected LINC00968 function in LUAD cells using the MTT, clone formation, and transwell assays, and tumor xenografts. Label-free quantitative proteomics, western blotting, a dual-luciferase reporter assay, immunofluorescence, and RNA immunoprecipitation assays were used to determine the correlations among LINC00968, miR-21-5p, and SMAD7. Gain- and loss-function approaches were used to explore the effects of LINC00968, miR-21-5p, and SMAD7 on cell proliferation, migration, and invasion.

LINC01436 Promotes the Progression of Gastric Cancer via Regulating miR-513a-5p/APE1 Axis

Background

Gastric cancer (GC) is one of the deadliest cancer worldwide. Multiple long non-coding RNAs (lncRNAs) are recently identified as crucial oncogenic factors or tumor suppressors in GC. In this study, we aimed to probe into the effect of LINC01436 on GC progression.

Methods

LINC01436 and miR-513a-5p expressions in GC tissue samples were measured using quantitative real-time polymerase chain reaction (qRT-PCR). Western blot was used to detect the expression of apurinic/apyrimidinic endodeoxyribonuclease 1 (APE1) expression. Human GC cell lines AGS and BGC-823 were employed to investigate the function and mechanism of LINC01436 in GC. Cell counting kit-8 (CCK-8) assay was used to assess the effect of LINC01436 on proliferation. Flow cytometry was utilized to explore the effect of LINC01436 on apoptosis, and Transwell assay was conducted to detect the effect of LINC01436 on the migration and invasion. Colony formation assay was performed to evaluate the effect of LINC01436 on radioresistance of GC cells. Furthermore, luciferase reporter assay and RNA immunoprecipitation assay were conducted to confirm the binding relationship between miR-513a-5p and LINC01436. Additionally, Western blot was used to study the regulatory function of LINC01436 and miR-513a-5p on APE1.

Results

LINC01436 expression of GC clinical samples was remarkably increased and LINC01436 was correlated with unfavorable pathological indexes. LINC01436 high expression was associated with shorter overall survival time. Its overexpression observably promoted the proliferation, metastasis and radioresistance of GC cells, and its knockdown suppressed the malignant phenotypes of GC cells. LINC01436 overexpression markedly reduced the miR-513a-5p expression via sponging it and enhanced the APE1 expression. MiR-513a-5p overexpression or APE1 knockdown reversed the effects of LINC01436 on GC cells.

Conclusion

LINC01436 is a molecular sponge of tumor suppressor miR-513a-5p, which indirectly enhances the APE1 expression and functions as the oncogenic lncRNA in GC.

Long noncoding RNA MIR99AHG promotes gastric cancer progression by inducing EMT and inhibiting apoptosis via miR577/FOXP1 axis

Background

Long non-coding RNAs (lncRNAs) play a vital role in the genesis and development of human cancer. LncRNA MIR99AHG has been reported to be upregulated in acute myeloid leukemia (AML); however, its function in gastric cancer (GC) is still not clear. Here we were aiming to screen the prognostic lncRNA candidates and to explore the function of MIR99AHG in GC.

Methods

We have preliminarily screened some candidate lncRNA biomarkers in GC tissues through analyzing microarray datasets. The expression level of MIR99AHG in GC cell lines and tissues was monitored via qPCR. Survival analysis was performed with the patients of our hospital and TCGA database cases. CCK-8 assay, trans-well assay and flow cytometry were performed to determine cell proliferation, invasion, migration and apoptosis. Meanwhile, a target of MIR99AHG was predicted and identified by luciferase reporter gene detection experiments.

Results

MIR99AHG was strongly up-regulated in human GC and contributed to cancer progression. Kaplan–Meier analysis revealed that up-regulating MIR99AHG expression was positively correlated with unfavorable overall survival (P < 0.01) of patients from our hospital and TCGA database. Knockdown of MIR99AHG expression inhibited cell proliferation, invasion, migration and promoted cell apoptosis. Moreover, MIR99AHG worked as an oncogenic gene though competing for endogenous RNA (ceRNA) of miR-577.

Conclusions

Our findings suggested that MIR99AHG contributes to malignant phenotypes of GC and may become a promising therapeutic target.

Effect of Curcumin and Its Derivates on Gastric Cancer: Molecular Mechanisms

Gastric carcinoma is one of the most prevalent malignancies and is associated with a high mortality. Chemotherapy is the principal therapeutic option in the treatment of gastric cancer, but its success rate is restricted by severe side effects and the prevalence of chemo-resistance. Curcumin is a polyphenolic compound derived from turmeric that has potent antioxidant, anti-inflammatory and anti-tumor effects. There is accumulating evidence that curcumin may prevent gastric cancer through regulation of oncogenic pathways. Furthermore some curcumin analogues and novel formulation of curcumin appear to have anti-tumor activity. The aim of this review was to give an overview of the therapeutic potential of curcumin and its derivatives against gastric cancer in preclinical and clinical studies.

Long Non-coding RNA FGD5-AS1 Regulates Cancer Cell Proliferation and Chemoresistance in Gastric Cancer Through miR-153-3p/CITED2 Axis

Background

In this study, we investigated the molecular mechanisms of human long non-coding RNA (lncRNA) FYVE RhoGEF And PH Domain Containing 5 Antisense RNA 1 (FGD5-AS1) and its downstream epigenetic axis, human microRNA-153-3p (hsa-miR-153-3p)/Cbp/P300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 (CITED2) in human gastric cancer.

Methods

Gastric cancer cell lines and clinical tumor samples were used to assess FGD5-AS1 expression levels. Lentivirus containing FGD5-AS1 small interfering RNA (sh-FGD5AS1) was applied to knockdown FGD5-AS1 expression. Cancer cells in vitro and in vivo proliferation, and 5-FU chemoresistance were assessed, respectively. Expressions of hsa-miR-153-3p/CITED2 were also assessed in FGD5-AS1-downregulated gastric cancer cells. Hsa-miR-153-3p was knocked down and CITED2 was upregulated to assess their direct functional correlations with FGD5-AS1 in gastric cancer.

Results

Both gastric cancer cell lines and human tumor samples showed aberrant FGD5-AS1 upregulation. Lentiviral-induced FGD5-AS1 knockdown reduced cancer proliferation, 5-FU chemoresistance in vitro, and tumorigenicity in vivo. Hsa-miR-153-3p/CITED2 axis was confirmed to be downstream of FGD5-AS1 in gastric cancer. Hsa-miR-153-3p inhibition or CITED2 upregulation reversed the tumor-suppressing effects of FGD5-AS1 downregulation on gastric cancer proliferation and 5-FU chemoresistance.

Conclusion

We demonstrated that FGD5-AS1 can regulate human gastric cancer cell functions, possibly through its downstream epigenetic axis of hsa-miR-153-3p/CITED2.

Non-coding RNAS and colorectal cancer liver metastasis

More than 50% of colorectal cancer (CRC) deaths are attributed to metastasis, and the liver is the most common distant metastatic site of CRC. The molecular mechanisms underlying CRC liver metastasis are very complicated and remain largely unknown. Accumulated evidence has shown that non-coding RNAs (NcRNAs) play critical roles in tumor development and progression. Here we reviewed the roles and underlying mechanisms of NcRNAs in CRC liver metastasis.

Non‑coding RNAs that regulate the Wnt/β‑catenin signaling pathway in gastric cancer: Good cop, bad cop? (Review)

Gastric cancer (GC) is one of the most common causes of cancer‑related mortality worldwide. Despite remarkable progress in the diagnosis and treatment of GC, a large number of cases are diagnosed as advanced GC, and treatment failure occurs. Emerging evidence has shown that non‑coding RNAs (ncRNAs), especially microRNAs (miRNAs) and long non‑coding RNAs (lncRNAs), play a vital role in the tumorigenesis and development of GC. Moreover, the pathogenesis of GC is closely related to aberrant activation of the Wnt (Wingless‑type MMTV integration site family) signaling pathway. ncRNAs serve as potential novel biomarkers in the clinical examination, prognosis and therapeutic targeting of GC. Furthermore, dysregulation of ncRNAs has been demonstrated to affect tumor initiation, epithelial‑mesenchymal transition (EMT), angiogenesis, tumor development, invasion, metastasis and resistance to therapy via the Wnt/β‑catenin signaling pathway. This review focuses on the role of ncRNAs in modulating the Wnt/β‑catenin signaling pathway in the pathogenesis of GC, which may provide a reference for the clinical diagnosis and treatment of GC.

MicroRNA Response and Toxicity of Potential Pathways in Human Colon Cancer Cells Exposed to Titanium Dioxide Nanoparticles

Titanium dioxide nanoparticles (TiO₂-NPs) are widely used for biomedical and food applications, the toxicity of TiO₂-NPs in vivo and in vitro has been elucidated, but the underlying cytotoxicity of TiO₂-NPs against microRNA remains largely unknown. The purpose of this study was to analyze microRNA profiling induced by TiO₂-NPs against NCM460 and HCT116 cell lines. Comparative analysis identified 34 and 24 microRNAs were significantly altered in the TiO₂-NPs treated cells at concentrations of 3 μg/mL and 30 μg/mL, respectively. Functional classification demonstrated that a large proportion of genes involved in metabolism, human disease, and environmental information process were significantly upregulated by TiO₂-NPs. Bioinformatics analysis suggested that microRNA 378 might be an early indicator of cellular response to exogenous stimuli with apoptotic signals. Furthermore, TiO₂-NPs significantly altered the expression of microRNA 378b and 378g in HCT116 and NCM460 cell lines at different concentrations from 3 to 6 μg/mL. These concentrations elicit high-sensitivity of stimuli response in colon cancer cells when exposed to the slight doses of TiO₂-NPs. Our study indicated that microRNAs 378b and 378g may play an important role in TiO₂-NPs-mediated colonic cytotoxicity, which may provide a valuable insight into the molecular mechanisms of potential risks in colitis and colon cancer.

LBX2-AS1 up-regulated by NFIC boosts cell proliferation, migration and invasion in gastric cancer through targeting miR-491-5p/ZNF703

BACKGROUND

The crucial role of long non-coding RNAs (lncRNAs) has been certified in human cancers. The lncRNAs with abnormal expressions could act as tumor inhibitors or oncogenes in the advancement of tumors. LBX2-AS1 was once reported to accelerate esophageal squamous cell carcinoma. Nonetheless, its function in gastric cancer (GC) remained a riddle.

METHODS

RT-qPCR was used to examine the expression of NFIC/LBX2-AS1/miR-491-5p/ZNF703 in GC cell lines. The functions of LBX2-AS1 in GC were appraised by colony formation, EdU, flow cytometry analysis, transwell and wound healing assays. Luciferase reporter, ChIP and RNA pull down assays were utilized to evaluate the interactions among genes.

RESULTS

LBX2-AS1 was up-regulated in GC cell lines. Knockdown of LBX2-AS1 repressed the proliferative, migratory, and invasive abilities of GC cells. Moreover, LBX2-AS1 was transcriptionally activated by NFIC. And LBX2-AS1 could bind with miR-491-5p. Besides, miR-491-5p depletion or ZNF703 upregulation could counteract the repressing effects of LBX2-AS1 silence on GC progression.

CONCLUSION

In a word, LBX2-AS1 up-regulated by NFIC promoted GC progression via targeting miR-491-5p/ZNF703, implying LBX2-AS1 was an underlying treatment target for GC patients.

LINC01272 Promotes Migration and Invasion of Gastric Cancer Cells via EMT

PURPOSE

Gastric cancer (GC) is the fifth most common tumor in the world, and most patients with GC have a poor prognosis. This study aimed to explore the biological influence and mechanism of LINC01272 in GC.

MATERIALS AND METHODS

Using bioinformatic analyses, we investigated the expression of LINC01272 in TCGA database and predicted the biological functions and mechanism of LINC01272 in GC. Then, we detected the expression of LINC01272 in GC cell lines, GC tissues, and corresponding normal tissues using real-time polymerase chain reaction (RT-PCR). Finally, we explored the migration and invasion ability of LINC01272 by wound-healing and Transwell assays and examined the expression of epithelial-mesenchymal transition (EMT)-related proteins through Western blotting.

RESULTS

We found that LINC01272 was upregulated in GC and was associated with GC staging and lymph node metastasis. The results of wound-healing and Transwell assays revealed that the LINC01272 was closely related to GC cell migration and invasion. LINC01272 knockdown inhibited the migration and invasion ability of GC cells by reducing the expression of EMT-related proteins. Overexpression of LINC01272 had the opposite effect.

CONCLUSION

Together, our results showed that LINC01272 promoted GC metastasis ability by regulating the expression of EMT-related proteins and could serve as a potential diagnostic biomarker for GC.

Hsa_circ_0001649 restrains gastric carcinoma growth and metastasis by downregulation of miR-20a

Background

Gastric carcinoma (GC) is a familiar carcinoma and serious threat to human health. We investigated the efficacy and mechanism of circular RNA hsa_circ_0001649 on the growth, migration, and invasion of GC cells.

Methods

microRNA (miR)‐20a and hsa_circ_0001649 expression was investigated by RT‐qPCR and was changed by cell transfection. CCK‐8, flow cytometry, and BrdU assays were, respectively, used to investigate the efficacies of hsa_circ_0001649 and miR‐20a on cell viability, apoptosis, and proliferation. Transwell assay was used to investigate the efficacies of hsa_circ_0001649 and miR‐20a on cell migration and invasion. Moreover, the levels of cyclin D1, Bax, cleaved caspase‐3, and signal pathway‐related proteins were investigated by Western blot.

Results

Hsa_circ_0001649 was downregulated in GC cells and tissues. Upregulation of hsa_circ_0001649 restrained viability, proliferation, migration, and invasion, while promoted apoptosis. Furthermore, miR‐20a was negatively regulated by hsa_circ_0001649 and miR‐20a overexpression reversed the efficacy of hsa_circ_0001649 upregulation. Finally, upregulation of hsa_circ_0001649 restrained ERK and Wnt/β‐catenin pathways while miR‐20a overexpression reversed these progresses.

Conclusion

Upregulation of hsa_circ_0001649 restrained GC cell growth and metastasis by downregulating miR‐20a and thereby inactivated ERK and Wnt/β‐catenin pathways.

MicroRNA-30a targets BECLIN-1 to inactivate autophagy and sensitizes gastrointestinal stromal tumor cells to imatinib

Gastrointestinal stromal tumors (GISTs), the most widespread type of sarcoma, contain driver gene mutations predominantly of receptor tyrosine kinase and platelet-derived growth factor receptor alpha. However, the inevitable development of resistance to imatinib (IM) cannot be fully attributed to secondary driver gene mutations. In this study, we investigated the role of microRNA-30a in sensitization of GIST cells to IM in vivo and in vitro. Higher levels of miR-30a were detected in GIST-T1 cells, which were more sensitive to IM than GIST-882 cells. IM treatment also reduced miR-30a levels, indicating the possible role of miR-30a in GIST IM resistance. Subsequently, miR-30a was confirmed to be an IM sensitizer via a mechanism that was attributed to its involvement in the regulation of cell autophagy. The interaction of miR-30a and autophagy in IM treated GIST cells was found to be linked by beclin-1. Beclin-1 knockdown increased IM sensitivity in GIST cell lines. Finally, miR-30a was confirmed to enhance IM sensitivity of GIST cells in mouse tumor models. Our study provides evidence for the possible role of miR-30a in the emergence of secondary IM resistance in GIST patients, indicating a promising target for overcoming this chemoresistance.

A Review of Research Progress in Multidrug-Resistance Mechanisms in Gastric Cancer

Gastric cancer is one of the most common malignant tumors, and it is also one of the leading causes of cancer death worldwide. Because of its insidious symptoms and lack of early dictation screening, many cases of gastric cancer are at late stages which make it more complicated to cure. For these advanced-stage gastric cancers, combination therapy of surgery, chemotherapy, radiotherapy and target therapy would bring more benefit to the patients. However, the drug-resistance to the chemotherapy restricts its effect and might lead to treatment failure. In this review article, we discuss the mechanisms which have been found in recent years of drug resistance in gastric cancer. And we also want to find new approaches to counteract chemotherapy resistance and bring more benefits to the patients.

WGCNA Co-Expression Network Analysis Reveals ILF3-AS1 Functions as a CeRNA to Regulate PTBP1 Expression by Sponging miR-29a in Gastric Cancer

Gastric cancer (GC) is one of the most common types of human cancers worldwide. However, the detail mechanisms underlying GC progression remained to be investigated. The present study identified 2823 differently expressed mRNAs and 441 differently expressed lncRNAs in GC. WGCNA was conducted to identify highly correlated lncRNAs and mRNAs. Bioinformatics analysis observed that these dysregulated lncRNAs were significantly associated with the regulation of angiogenesis, cell division, cell-cell adhesion, blood vessel development, adaptive immune response, gastric acid secretion, immune response. Co-expression analysis identified ILF3-AS1 was a key lncRNA involved in regulating GC progression. Loss of function assays showed that knockdown of ILF3-AS1 significantly suppressed GC cell proliferation and metastasis. Mechanically, the results indicate that ILF3-AS1 could enhance PTBP3 expression as an miR-29a sponge, thereby promoting the proliferation and metastasis of GC cells. Our work suggests that the ILF3-AS1/miR-29a/PTBP3 axis may be a potential target for the clinical diagnosis and treatment of GC.

The potential mechanism of miR-130b on promotion of the invasion and metastasis of hepatocellular carcinoma by inhibiting Notch-Dll1

Introduction: This study aimed to elucidate the regulatory role and molecular regulation mechanism of miR-130b gene in the process of invasion and metastasis of hepatocarcinoma, and provide a theoretical basis for seeking of effective prevention and treatment of new targets for hepatocellular carcinoma.Materials and methods: The expression level of miR-130b gene in hepatocarcinoma tissues was determined by qRT-PCR. The biological function and mechanism of miR-130b gene were verified by cell and animal models, and the target gene was verified by double luciferase assay.Results: In the liver cancer tissues of patients with metastasis, the expression level of miR-130b gene was increased, and the difference was significantly significant (p < 0.05). Evaluation of independent risk factors for overall survival showed significant difference (p < 0.01). Up-regulation of miR-130b in MHCC97L- subpopulation cells significantly enhanced the invasion and migration ability, and the difference was statistically significant (p < 0.05). The invasion and migration ability of MHCC97H + subpopulation cells with increased expression of miR-130b was significantly decreased, and the difference was notably significant (p < 0.05). When the expression of miR-130b in MHCC97H + subpopulation cells was inhibited, the expressions of Notch-Dll1 and SOX2, Nanog and E2F3 proteins in transplanted tumor tissues were significantly higher than those in other groups (p < 0.05). When miR-130b in MHCC97L- subpopulation cells was up-regulated, the expressions of Notch-Dll1 and Bcl-2, CCND1, Nanog and MET proteins in transplanted tumor tissues were significantly increased than those in other groups (p < 0.05). The prediction results of bioinformatics data suggest that the target gene of miR-130b may be Notch-Dll1 gene. The experiment of luciferase reporter gene confirmed that miR-130b gene can be inhibited and contains fluorescent reporter gene with complementary binding site, lost activity.Conclusion: The miR-130b gene can inhibit the protein expression of Notch-Dll1, and it can promote the invasion and metastasis of liver cancer cells.

Lnc-MAP6-1:3 knockdown inhibits osteosarcoma progression by modulating Bax/Bcl-2 and Wnt/β-catenin pathways

Osteosarcoma (OS) is the most common type of malignant bone tumor that affects children and adolescents. Still, the cellular and molecular mechanisms driving the development of this disease remain poorly understood. In this study, numerous dysregulated lncRNAs were identified by RNA-seq. As a result, we were able to find a novel lncRNA Lnc-MAP6-1:3 which is highly expressed in osteosarcoma. Using a set of approaches including gene knockdown, RT-PCR, oncogenic function assay and western blotting, we observed that knockdown of Lnc-MAP6-1:3 expression suppressed cell proliferation and colony formation, and promoted apoptosis in vitro. For the first time, we have identified that Lnc-MAP6-1:3 potentially influence the malignant behavior of osteosarcoma via Bax/Bcl-2 and Wnt/β-catenin signaling pathways. Henceforth, Lnc-MAP6-1:3 may provide a new molecular route of research and therapeutic applications for the diagnosis and treatment of osteosarcoma.

Analysis of Long Non-Coding RNA Expression Profile and Functional Study of LOC389332 in Early Gastric Cancer

Background

Long non-coding RNAs (LncRNAs) could potentially function as diagnostic markers for gastric carcinoma. Nevertheless, the expression profile and biological feature of LncRNAs in early gastric cancer (EGC) remains to be explored.

Material/Methods

LncRNA expression microarray analysis was performed on 6 paired EGC tissues. One deregulated LncRNA, LOC389332, was validated using a quantitative reverse-transcription polymerase chain reaction (qRT-PCR) assay using independent tissue samples and cell lines. The Cell Counting Kit-8 (CCK-8) assay and wound healing assay were conducted to evaluate its influences on the proliferation and migration of gastric cancer cells. LncRNA expression microarray and gene ontology (GO) analysis were also performed on the LOC389332 knockdown cell line model to explore the molecular feature of LOC389332 in gastric carcinoma.

Results

The LncRNA expression profiling showed that 72 LncRNAs were significantly differentially expressed in EGC tissues. The results in the validation phase revealed that LOC389332 was remarkably overexpressed in gastric carcinoma tissues, precancerous lesions, and gastric cancer cells. Functional study showed that knockdown of LOC389332 expression could inhibit cell proliferation and migration. LncRNA expression microarray on the LOC389332 knockdown cell line model revealed that 393 mRNAs were differentially expressed. The GO enrichment analysis indicated that the downregulated genes were mainly associated with cell membrane function, signal transmission process, and cell adhesion process.

Conclusions

The LncRNA expression profile between EGC and gastritis tissues was significantly different. LOC389332 was potential non-coding oncogenes in gastric cancer, and it may perform its function through altering cell membrane function, signal transmission, and cell adhesion.

IDLDA: An Improved Diffusion Model for Predicting LncRNA-Disease Associations

It has been demonstrated that long non-coding RNAs (lncRNAs) play important roles in a variety of biological processes associated with human diseases. However, the identification of lncRNA–disease associations by experimental methods is time-consuming and labor-intensive. Computational methods provide an effective strategy to predict more potential lncRNA–disease associations to some degree. Based on the hypothesis that phenotypically similar diseases are often associated with functionally similar lncRNAs and vice versa, we developed an improved diffusion model to predict potential lncRNA–disease associations (IDLDA). As a result, our model performed well in the global and local cross-validations, which indicated that IDLDA had a great performance in predicting novel associations. Case studies of colon cancer, breast cancer, and gastric cancer were also implemented, all lncRNAs which ranked top 10 in both databases were verified by databases and related literature. The results showed that IDLDA might play a key role in biomedical research.