A Competing Endogenous RNA Network Reveals Novel Potential lncRNA, miRNA, and mRNA Biomarkers in the Prognosis of Human Colon Adenocarcinoma

Identification and validation of an m5C-related lncRNA signature for predicting prognosis and immune response in clear cell renal cell carcinoma

This study investigated whether m5C-related Long non-coding RNAs (lncRNAs) can predict clear cell renal cell carcinoma (ccRCC) patient prognosis. Co-expression and Cox regression analyses identified 9 prognostic lncRNAs, which were closely associated with tumor immune characteristics and immune escape. The model also predicted the sensitivity of drugs, including Entinostat, SB216763, and Sapitinib. In vitro experiments showed that GNG12-AS1 inhibited ccRCC cell proliferation and migration by reducing the activity of the ERK/GSK-3β/β-catenin pathway. Overall, these findings suggest that the 9 m5C-related lncRNAs can accurately predict ccRCC patient prognosis, providing potential applications for clinical and immunotherapy approaches. GNG12-AS1 emerges as a promising prognostic biomarker for predicting survival outcomes in ccRCC, potentially influencing cell migration through the activation of the ERK/GSK-3β/β-catenin signaling pathway.

LINC01857 promotes cell proliferation and migration while dampening cell apoptosis in pancreatic cancer by upregulating CDC42EP3 via miR-450b-5p

Background

Pancreatic cancer (PC) is a devastating human malignancy with a poor survival outcome (5-year survival less than 10 %). In recent years, the regulatory roles of long non-coding RNAs (lncRNAs) in various types of cancers have been widely reported. Based on bioinformatics analysis, LINC01857 is shown to be highly expressed in PC tissue. Nevertheless, the role of LINC01857 in PC is limitedly reported. Hence, this study aimed to explore the effects of lncRNA LINC01857 on PC cell process and the related mechanism.

Methods

RT-qPCR and fluorescence in situ hybridization (FISH) assay were conducted to measure LINC01857 expression and distribution in PANC-1 and MIA PaCa-2 cells. Colony formation and wound healing assays as well as flow cytometry analyses were employed to estimate the proliferation, migration, and apoptosis of PC cells transfected with pcDNA3.1-LINC01857 or si-LINC01857 compared with the behavior of PC cells transfected with empty pcDNA3.1 vector (control) or si-negative control (NC). Furthermore, RNA pulldown and luciferase reporter assays were utilized to demonstrate the interaction of LINC01857 and miR-450b-5p or to validate the binding of miR-450b-5p and cell division cycle 42 effector protein 3 (CDC42EP3).

Results

LINC01857 was highly expressed in PANC-1 and MIA PaCa-2 cells in contrast to its expression in pancreatic ductal epithelial cells (8.9 folds and 7.1 folds, p < 0.001). Silencing LINC01857 significantly reduced cell proliferation and migration while enhancing apoptosis (p < 0.0005). In contrast, overexpression of LINC01857 markedly (p < 0.05) accelerated these malignant behavior of PC cells. MiR-450b-5p was targeted and inversely regulated by LINC01857. Moreover, CDC42EP3 was verified to be targeted by miR-450b-5p, and CDC42EP3 was correlated to LINC01857 in a positive manner (p < 0.001). Rescue experiments manifested that silencing CDC42EP3 effectively (p < 0.05) reversed the promoting effect of LINC01857 on malignant behavior of PC cells.

Conclusion

LINC01857 promotes PC cell proliferation and migration while obstructing cell apoptosis by binding to miR-450b-5p and thus regulating CDC42EP3 expression. The study presents a novel and promising regulatory axis, which holds potential for the identification of biomarkers and development of therapeutic strategies for PC treatment.

Sodium Butyrate Inhibits the Malignant Proliferation of Colon Cancer Cells via the miR-183/DNAJB4 Axis

Colorectal carcinoma (CRC) is one of the most common malignant tumors in the digestive tract. It was found that butyric acid could inhibit the expression of miR-183 to slow down malignant progression of CRC in the early stage. However, its regulatory mechanism remains unclear. This study screened the IC50 value of butyrate on inhibition of CRC cells malignant progression. Its inhibitory effects were detected by MTT assay, colony formation experiment, Transwell migration experiment, and apoptosis evaluation by flow cytometry. Next, the expressions of miR-183 and DNAJB4 were, respectively, determined in butyrate treated and miR-183 analog or si-DNAJB4-transfected CRC cells to further detect the role of upregulated miR-183 or silencing DNAJB4 in CRC cells malignant progression. Subsequently, the targeted regulatory relationship between miR-183 and si-DNAJB4 was confirmed by bioinformatic prediction tools and double luciferase report genes analysis method. The regulatory mechanism of butyrate on miR-183/DNAJB4 axis signal pathway was evaluated in molecular level, and verified in nude mouse xerograft tumor model and immunohistochemical analysis tests of Ki67 positive rates. The results displayed that butyrate with increased concentration can hinder the proliferation and improve apoptosis of CRC cells by decreasing the expression of miR-183. Thus, butyrate reduces miR-183 expression and increases DNAJB4 expression via the miR-183/DNAJB4 axis, ultimately inhibiting the malignant progression and increasing apoptosis of CRC. While over expression of miR-183 downregulate the expression of DNAJB4, which can reverse the inhibitory effect of butyrate.

Expression of ITPR2 regulated by lncRNA-NONMMUT020270.2 in LPS-stimulated HT22 cells

Background

Long non-coding RNA (lncRNA)-NONMMUT020270.2 is downregulated and co-expressed with inositol 1,4,5-trisphosphate receptor type 2 (ITPR2) in the hippocampus of Alzheimer's disease (AD) mice. However, whether the expression of ITPR2 was regulated by lncRNA-NONMMUT020270.2 remains unclear. we aimed to investigate regulating relationship of lncRNA-NONMMUT020270.2 and ITPR2.

Methods

HT22 cells were firstly transfected with the pcDNA3.1-lncRNA-NONMMUT020270.2 overexpression plasmid or with the lncRNA-NONMMUT020270.2 smart silencer, and then were stimulated with lipopolysaccharide (LPS) for 24h. The mRNA expression levels of lncRNA-NONMMUT020270.2 and ITPR2 were measured by reverse transcription-quantitative PCR. Cell viability was assessed using a Cell Counting Kit 8 assay. The expression of Aβ1-42 was detected by ELISA. The expression levels of p-tau, caspase-1, and inositol trisphosphate receptor (IP3R) proteins were detected by western-blotting. Nuclear morphological changes were detected by Hoechst staining. Flow cytometry and Fluo-3/AM were carried out to determine cell apoptosis and the intracellular Ca2+.

Results

LPS significantly decreased cell viability, and ITPR2 mRNA and IP3R protein expression levels. While it markedly enhanced the expression levels of p-tau and Aβ1-42, cell apoptosis rate, as well as intracellular Ca2+ concentration (P < 0.05). In addition, lncRNA-NONMMUT020270.2 overexpression significantly increased the expressions levels of ITPR2 mRNA and IP3R protein (P < 0.05), and inhibited expression of p-tau and Aβ1-42, cell apoptosis rate, and reduced intracellular Ca2+ concentration (P < 0.05). By contrast, lncRNA-NONMMUT020270.2 silencing notably downregulated expressions levels of ITPR2 mRNA and IP3R protein (P < 0.05), and elevated expression levels of p-tau and Aβ1-42, cell apoptosis rate, and intracellular Ca2+ concentration (P < 0.05).

Conclusion

lncRNA-NONMMUT020270.2 was positively correlated with ITPR2 expression in LPS-induced cell. Downregulating the lncRNA-NONMMUT020270.2 and ITPR2 may promote cell apoptosis and increase intracellular Ca2+ concentration.

Biological role of long non-coding RNA KCNQ1OT1 in cancer progression

Long non-coding RNAs (lncRNAs) are a type of RNAs that are more than 200 nucleotides without protein-coding potential. In recent years, more and more attention has been paid to the role of lncRNAs in cancer pathogenesis. LncRNA KCNQ1 overlapping transcript 1 (KCNQ1OT1) is located on chromosome 11p15.5 with a total length of 91 kb and is highly expressed in various malignancies, which is closely related to tumor growth, lymph node metastasis, survival cycle and recurrence rate. In addition, KCNQ1OT1 is involved in the regulation of PI3K/AKT and Wnt/β-catenin signaling pathways. In this review, the mechanism and related progress of KCNQ1OT1 in different cancers were reviewed. It was found that KCNQ1OT1 can stabilize mRNA expression through sponging miRNA, which not only induced tumor cell proliferation, migration, invasion, drug resistance, epithelial-mesenchymal transition (EMT) and inhibited cell apoptosis in vitro, but also promoted tumor growth and metastasis in vivo. Therefore, as a new biomarker and therapeutic target, KCNQ1OT1 has broad prospects for the diagnosis and treatment of different cancers.

Transcriptional Dysregulations of Seven Non-Differentially Expressed Genes as Biomarkers of Metastatic Colon Cancer

Background: Colon cancer (CC) is common, and the mortality rate greatly increases as the disease progresses to the metastatic stage. Early detection of metastatic colon cancer (mCC) is crucial for reducing the mortality rate. Most previous studies have focused on the top-ranked differentially expressed transcriptomic biomarkers between mCC and primary CC while ignoring non-differentially expressed genes. Results: This study proposed that the complicated inter-feature correlations could be quantitatively formulated as a complementary transcriptomic view. We used a regression model to formulate the correlation between the expression levels of a messenger RNA (mRNA) and its regulatory transcription factors (TFs). The change between the predicted and real expression levels of a query mRNA was defined as the mqTrans value in the given sample, reflecting transcription regulatory changes compared with the model-training samples. A dark biomarker in mCC is defined as an mRNA gene that is non-differentially expressed in mCC but demonstrates mqTrans values significantly associated with mCC. This study detected seven dark biomarkers using 805 samples from three independent datasets. Evidence from the literature supports the role of some of these dark biomarkers. Conclusions: This study presented a complementary high-dimensional analysis procedure for transcriptome-based biomarker investigations with a case study on mCC.

Good or bad: Paradox of plasminogen activator inhibitor 1 (PAI-1) in digestive system tumors

The fibrinolytic system is involved in many physiological functions, among which the important members can interact with each other, either synergistically or antagonistically to participate in the pathogenesis of many diseases. Plasminogen activator inhibitor 1 (PAI-1) acts as a crucial element of the fibrinolytic system and functions in an anti-fibrinolytic manner in the normal coagulation process. It inhibits plasminogen activator, and affects the relationship between cells and extracellular matrix. PAI-1 not only involved in blood diseases, inflammation, obesity and metabolic syndrome but also in tumor pathology. Especially PAI-1 plays a different role in different digestive tumors as an oncogene or cancer suppressor, even a dual role for the same cancer. We term this phenomenon "PAI-1 paradox". PAI-1 is acknowledged to have both uPA-dependent and -independent effects, and its different actions can result in both beneficial and adverse consequences. Therefore, this review will elaborate on PAI-1 structure, the dual value of PAI-1 in different digestive system tumors, gene polymorphisms, the uPA-dependent and -independent mechanisms of regulatory networks, and the drugs targeted by PAI-1 to deepen the comprehensive understanding of PAI-1 in digestive system tumors.

Regulation of secretory pathway kinase or kinase-like proteins in human cancers

Secretory pathway kinase or kinase-like proteins (SPKKPs) are effective in the lumen of the endoplasmic reticulum (ER), Golgi apparatus (GA), and extracellular space. These proteins are involved in secretory signaling pathways and are distinctive from typical protein kinases. Various reports have shown that SPKKPs regulate the tumorigenesis and progression of human cancer via the phosphorylation of various substrates, which is essential in physiological and pathological processes. Emerging evidence has revealed that the expression of SPKKPs in human cancers is regulated by multiple factors. This review summarizes the current understanding of the contribution of SPKKPs in tumorigenesis and the progression of immunity. With the epidemic trend of immunotherapy, targeting SPKKPs may be a novel approach to anticancer therapy. This study briefly discusses the recent advances regarding SPKKPs.

LncRNA KCNQ1OT1: Molecular mechanisms and pathogenic roles in human diseases

Long non-coding RNAs (lncRNAs) exhibit a length more than 200 nucleotides and they are characterized by non-coding RNAs (ncRNA) not encoded into proteins. Over the past few years, the role and development of lncRNAs have aroused the rising attention of researchers. To be specific, KCNQ1OT1, the KCNQ1 opposite strand/antisense transcript 1, is clearly classified as a regulatory ncRNA. KCNQ1OT1 is capable of interacting with miRNAs, RNAs and proteins, thereby affecting gene expression and various cell functions (e.g., cell proliferation, migration, epithelial-mesenchymal transition (EMT), apoptosis, viability, autophagy and inflammation). KCNQ1OT1 is dysregulated in a wide range of human diseases (e.g., cardiovascular disease, cancer, diabetes, osteoarthritis, osteoporosis and cataract), and it is speculated to act as a therapeutic target for treating various human diseases. On the whole, this review aims to explore the biological functions, underlying mechanisms and pathogenic roles of KCNQ1OT1 in human diseases.

Systematic analysis competing endogenous RNA coexpression network as a potentially prediction prognostic biomarker for colon adenocarcinoma

Colon adenocarcinoma (COAD) is one of the most common types of colon cancer, represents a major public health issue due to its high incidence and mortality. Competing endogenous RNAs (ceRNAs) hypothesis has generated a great interest in the study of molecular biological mechanisms of cancer progression. The aim of this study was to identify potential prediction prognostic biomarker associated with progression of COAD and illuminate regulatory mechanisms. Two RNA sequencing datasets downloaded from the Genotype-Tissue Expression and TCGA. The differentially expressed RNAs were analyzed. Weighted correlation network analysis was used to analyze the similarity of genes model with a trait in the network. Interactions between lncRNAs, miRNAs, and target mRNAs were predicted by MiRcode, starBase, miRTarBase, miRDB, and TargetScan, and the risk score of mRNAs was established. Based on the identified prognostic signature and independent clinical factors, then the nomogram survival model was built. Totally, we identified 3537 differentially expressed mRNAs, 2379 lncRNAs, and 449 microRNAs. Based on the 8 prognosis-associated mRNAs (CCNA2 + CEBPA + NEBL + SOX9 + DLG4 + RIMKLB + TCF7L1 + TUB), the risk score was proposed. After the independent clinical prognostic factors were identified, the nomogram survival model was built. LncRNA-miRNA-mRNA ceRNA network was built by 68 lncRNAs, 4 miRNAs, and 6 mRNAs, which might serve as prognostic biomarkers of COAD. These findings suggest several genes in ceRNA network might be novel important prognostic biomarkers and potential targets for COAD. CeRNA networks could provide further insight into the mRNA-related regulatory mechanism and COAD prognosis.

DNMBP-AS1 Regulates NHLRC3 Expression by Sponging miR-93-5p/17-5p to Inhibit Colon Cancer Progression

Long non-coding RNAs (LncRNAs) act as competing endogenous RNAs (ceRNAs) in colon cancer (CC) progression, via binding microRNAs (miRNAs) to regulate the expression of corresponding messenger RNAs (mRNAs). This article aims to explore the detailed molecular mechanism of ceRNA in CC. Top mad 5000 lncRNAs and top mad 5000 mRNAs were used to perform weighted gene co-expression network analysis (WGCNA), and key modules were selected. We used 405 lncRNAs in the red module and 145 mRNAs in the purple module to build the original ceRNA network by online databases. The original ceRNA network included 50 target lncRNAs, 41 target miRNAs, and 34 target mRNAs. Fifty target lncRNAs were used to establish a prognostic risk model by univariate and least absolute shrinkage and selection operator (LASSO) Cox regression analyses. LncRNAs in the risk model were used to build the secondary ceRNA network, which contained 9 lncRNAs in the risk model, 35 miRNAs, and 29 mRNAs. Survival analyses of 29 mRNAs in the secondary ceRNA network have shown HOXA10 and NHLRC3 were identified as crucial prognostic factors. Finally, we constructed the last ceRNA network including 5 lncRNAs in the risk model, 8 miRNAs, and 2 mRNAs related to prognosis. Quantitative real-time polymerase chain reaction (qRT-PCR) results revealed that DNMBP-AS1 and FAM87A were down-regulated in CC cells and tissues. Function assays showed that over-expression of DNMBP-AS1 and FAM87A inhibited CC cells proliferation and migration. Mechanism study showed that DNMBP-AS1 served as miR-93-5p/17-5p sponges and relieved the suppression effect of miR-93-5p/17-5p on their target NHLRC3. Our study suggested that DNMBP-AS1 inhibited the progression of colon cancer through the miR-93-5p/17-5p/NHLRC3 axis, which could be potential therapeutic targets for CC.

Transcriptional expressions of hsa-mir-183 predicted target genes as independent indicators for prognosis in bladder urothelial carcinoma

OBJECTIVE

To uncover novel prognostic and therapeutic targets for BLCA, our study is the first to investigate the role of hsa-mir-183 and its up-regulated predicted target genes in bladder urothelial carcinoma.

METHODS

To address this issue, our study explored the roles of hsa-mir-183 predicted target genes in the prognosis of BLCA via UALCAN, Metascape, Kaplan-Meier plotter, Human Protein Atlas, TIMER2.0, cBioPortal and Genomics of Drug Sensitivity in Cancer databases.

RESULTS

High transcriptional expressions of PDCD6, GNG5, PHF6 and MAL2 were markedly relevant to favorable OS in BLCA patients, whereas SLC25A15 and PTDSS1 had opposite expression significance. Additionally, high transcriptional expression of PDCD6, GNG5, PHF6, MAL2, SLC25A15 and PTDSS1 were significantly correlated with BLCA individual cancer stages and molecular subtypes. Furthermore, high mutation rate of PDCD6, MAL2, SLC25A15 and PTDSS1 were observed. Finally, TP53 mutation of PDCD6, GNG5, PHF6, MAL2, SLC25A15 and PTDSS1 has guiding significance for drug selection in BLCA.

CONCLUSIONS

PDCD6, GNG5, PHF6, MAL2, SLC25A15 and PTDSS1 could be the advanced independent indicators for prognosis of BLCA patients, and TP53-mutation might be a biomarker for drug option in BLCA patients.

Cancer-Associated Fibroblasts: Mechanisms of Tumor Progression and Novel Therapeutic Targets

Simple Summary

The tumor microenvironment plays an important role in determining the biological behavior of several of the more aggressive malignancies. Among the various cell types evident in the tumor “field”, cancer-associated fibroblasts (CAFs) are a heterogenous collection of activated fibroblasts secreting a wide repertoire of factors that regulate tumor development and progression, inflammation, drug resistance, metastasis and recurrence. Insensitivity to chemotherapeutics and metastatic spread are the major contributors to cancer patient mortality. This review discusses the complex interactions between CAFs and the various populations of normal and neoplastic cells that interact within the dynamic confines of the tumor microenvironment with a focus on the involved pathways and genes.

Abstract

Cancer-associated fibroblasts (CAFs) are a heterogenous population of stromal cells found in solid malignancies that coexist with the growing tumor mass and other immune/nonimmune cellular elements. In certain neoplasms (e.g., desmoplastic tumors), CAFs are the prominent mesenchymal cell type in the tumor microenvironment, where their presence and abundance signal a poor prognosis in multiple cancers. CAFs play a major role in the progression of various malignancies by remodeling the supporting stromal matrix into a dense, fibrotic structure while secreting factors that lead to the acquisition of cancer stem-like characteristics and promoting tumor cell survival, reduced sensitivity to chemotherapeutics, aggressive growth and metastasis. Tumors with high stromal fibrotic signatures are more likely to be associated with drug resistance and eventual relapse. Clarifying the molecular basis for such multidirectional crosstalk among the various normal and neoplastic cell types present in the tumor microenvironment may yield novel targets and new opportunities for therapeutic intervention. This review highlights the most recent concepts regarding the complexity of CAF biology including CAF heterogeneity, functionality in drug resistance, contribution to a progressively fibrotic tumor stroma, the involved signaling pathways and the participating genes.

Screening and Identification of Putative Long Non-Coding RNA in Childhood Obesity: Evaluation of Their Transcriptional Levels

Background and Methods: Long non-coding RNAs (LncRNAs) and microRNAs are involved in the pathogenesis of obesity, a multifactorial disease that is characterized by inflammation, cardiometabolic complications, and increased cancer risk among other co-morbidities. The up/down regulation of LncRNAs and microRNAs may play an important role in this condition to identify new diagnostic/prognostic markers. The aim of the study was to identify circulating inflammatory LncRNAs in obese adolescents (n = 54) and to evaluate whether their expression behaved differently compared to normal-weight adolescents (n = 26). To have a more complete insight, the expression of some circulating miRNAs that are linked to obesity (miR-33a, miR-223, miR-142, miR-199a, miR-181a, and miR-4454) were also analyzed. Results: LncRNAs and miRNAs were extracted simultaneously from plasma samples and amplified by Real-Time PCR. Among the 86 LncRNAs that were analyzed with custom pre-designed plates, only four (RP11-347E10.1, RP11-10K16.1, LINC00657, and SNHG12) were amplified in both normal-weight and obese adolescents and only SNHG12 showed significantly lower expression compared to the normal-weight adolescents (p = 0.026). Circulating miRNAs showed a tendency to increase in obese subjects, except for miR-181a expression. LncRNAs and miRNAs correlated with some clinical and metabolic parameters. Conclusions: Our results suggest the importance of these new biomarkers to better understand the molecular mechanisms of childhood obesity and its metabolic disorder.

Weighted correlation network analysis revealed novel long non-coding RNAs for colorectal cancer

Colorectal cancer (CRC) is one of the most prevalent cancers worldwide, which after breast, lung and, prostate cancers, is the fourth prevalent cancer in the United States. Long non-coding RNAs (lncRNAs) have an essential role in the pathogenesis of CRC. Therefore, bioinformatics studies on lncRNAs and their target genes have potential importance as novel biomarkers. In the current study, publicly available microarray gene expression data of colorectal cancer (GSE106582) was analyzed with the Limma, Geoquery, Biobase package. Afterward, identified differentially expressed lncRNAs and their target genes were inserted into Weighted correlation network analysis (WGCNA) to obtain modules and hub genes. A total of nine differentially expressed lncRNAs (LINC01018, ITCH-IT, ITPK1-AS1, FOXP1-IT1, FAM238B, PAXIP1-AS1, ATP2B1-AS1, MIR29B2CHG, and SNHG32) were identified using microarray data analysis. The WGCNA has identified several hub genes for black (LMOD3, CDKN2AIPNL, EXO5, ZNF69, BMS1P5, METTL21A, IL17RD, MIGA1, CEP19, FKBP14), blue (CLCA1, GUCA2A, UGT2B17, DSC2, CA1, AQP8, ITLN1, BEST4, KLF4, IQCF6) and turquoise (PAFAH1B1, LMNB1, CACYBP, GLO1, PUM3, POC1A, ASF1B, SDCCAG3, ASNS, PDCD2L) modules. The findings of the current study will help to improve our understanding of CRC. Moreover, the hub genes that we have identified could be considered as possible prognostic/diagnostic biomarkers. This study led to the determination of nine lncRNAs with no previous association with CRC development.

Mechanism and Role of the Neuropeptide LGI1 Receptor ADAM23 in Regulating Biomarkers of Ferroptosis and Progression of Esophageal Cancer

Background

According to recent studies, ferroptosis is closely related to the efficacy and prognosis of tumour treatment. However, the role of ferroptosis in esophageal squamous cell carcinoma (ESCC) has not been explored comprehensively.

Materials and Methods

The esophageal cancer (EC) transcriptome data was downloaded from The Cancer Genome Atlas (TCGA), then analyzed, to obtain the differentially expressed messenger RNA (mRNA), microRNA (miRNA), and long noncoding RNA (lncRNA) between groups with the low and high Ferroptosis Potential Index (FPI) and construct a ferroptosis-associated ceRNA network. In addition, the expression of ARHGEF26-AS1 and miR-372-3p in ESCC cell lines was assessed, and the appropriate cell lines were selected. The interaction between ARHGEF26-AS1, miR-372-3p, and ADAM23 was also determined through a dual-luciferase reporter assay. Moreover, the Western blot, Cell Counting Kit-8 (CCK-8), wound healing, cell viability, and cell death assays were conducted to establish the biological functions of the ARHGEF26-AS1/miR-372-3p/ADAM23 pathway in ESCCs.

Results

An FPI scoring model reflecting the activity of the ferroptosis pathway was constructed, and a ferroptosis-associated ceRNA network was established. The findings revealed that low expression of ADAM23 and ARHGEF26-AS1 as well as high expression of miR-372-3p was associated with poor prognosis and a lower FPI score in EC patients. Functionally, overexpression of ADAM23 and ARHGEF26-AS1 and the miR-372-3p inhibitor not only promoted ferroptosis in ESCC cells in vitro but also inhibited the proliferation and migration of cells. Mechanistically, ARHGEF26-AS1 upregulated the expression of ADAM23 by competitively binding to miR-372-3p.

Conclusions

The study showed that the lncRNA, ARHGEF26-AS1 acts as a miR-372-3p sponge that regulates the neuropeptide LGI1 receptor ADAM23 expression. This in turn not only inhibits the proliferation and migration of ESCC cells but also upregulates the ferroptosis pathway. A neuropeptide-related ferroptosis regulatory pathway was identified in this study.

Novel miR-5088-5p promotes malignancy of breast cancer by inhibiting DBC2

Breast cancer is the most common female cancer in the world. Despite the active research on metastatic breast cancer, the treatment of breast cancer patients is still difficult because the mechanism is not well known. Therefore, research on new targets and mechanisms for diagnosis and treatment of breast cancer patients is required. On the other hand, microRNA (miRNA) has the advantage of simultaneously regulating the expression of many target genes, so it has been proposed as an effective biomarker for the treatment of various diseases including cancer. This study analyzed the role and mechanism of DBC2 (deleted in breast cancer 2), which is known to inhibit its expression in breast cancer, and proposed microRNA (miR)-5088-5p, which regulates its expression. It was revealed that the biogenesis of miR-5088-5p was upregulated by hypomethylation of its promoter, promoted by Fyn, and was involved in malignancy in breast cancer. With the use of the cellular level, clinical samples, and published data, we verified that the expression patterns of DBC2 and miR-5088-5p were negatively related, suggesting the potential as novel biomarkers for the diagnosis of breast cancer patients.

Identification and validation of 12 immune-related genes as a prognostic signature for colon adenocarcinoma

Colon adenocarcinoma (COAD) is a common malignant tumor of the digestive tract that threatens human health seriously. Thus, it is urgent to explore biomarkers that can be used to evaluate a patient's survival prognosis overall as a supplementary treatment. RNA-seq expression profiles were downloaded from The Cancer Genome Atlas and Gene Expression Omnibus, and Lasso and multivariate Cox regression analyses were used for developing the prognostic model. Finally, a nomogram comprising the prognostic model was established to evaluate survival overall. A risk model comprised of a total of 12 immune-related gene pairs was constructed. Further analysis revealed the model's independent prognostic ability in relation to other clinical characteristics. This model's nomogram could help clinicians choose personalized treatment for COAD patients. This model has significant potential to complement COAD's clinical identifying characteristics, and also provide new insights into the identification of colon cancer patients with a high risk of death.

Long non-coding RNA SLC25A25-AS1 exhibits oncogenic roles in non-small cell lung cancer by regulating the microRNA-195-5p/ITGA2 axis

Long non-coding RNA SLC25A25 antisense RNA 1 (SLC25A25-AS1) exerts antitumour activity in colorectal cancer. The present study investigated whether SLC25A25-AS1 is implicated in the aggressiveness of non-small cell lung cancer (NSCLC) and the possible underlying mechanism. SLC25A25-AS1 expression in NSCLC was determined by reverse transcription-quantitative PCR. The proliferation, apoptosis, migration and invasion of NSCLC cells were tested in vitro through cell counting kit-8 assay, flow cytometry analysis, Transwell migration and invasion assays, followed by in vivo validation using animal experiments. Additionally, the competitive endogenous RNA theory for SLC25A25-AS1, microRNA-195-5p (miR-195-5p) and integrin α2 (ITGA2) was identified using subcellular fractionation, bioinformatics analysis, reverse transcription-quantitative PCR, western blotting, a luciferase assay and RNA immunoprecipitation. As compared with normal lung tissues, increased expression of SLC25A25-AS1 was demonstrated in NSCLC tissues using The Cancer Genome Atlas database.. In addition, SLC25A25-AS1 was overexpressed in both NSCLC tissues and cell lines. High SLC25A25-AS1 expression was markedly associated with shorter overall survival time of patients with NSCLC. SLC25A25-AS1 silencing impeded NSCLC cell proliferation and triggered apoptosis, while restricting cell migration and invasion. Tumour growth in vivo was also impaired by SLC25A25-AS1 silencing. Mechanistically, SLC25A25-AS1 was demonstrated to be an miR-195-5p sponge in NSCLC cells. miR-195-5p mimics decreased ITGA2 expression in NSCLC cells by directly targeting ITGA2, and SLC25A25-AS1 interference decreased ITGA2 expression by sequestering miR-195-5p. Furthermore, the antitumour effects of SLC25A25-AS1 silencing on malignant behaviours were counteracted when ITGA2 was restored or when miR-195-5p was silenced. In summary, by controlling the miR-195-5p/ITGA2 axis, SLC25A25-AS1 served tumour-promoting roles in NSCLC cells. Therefore, the SLC25A25-AS1/miR-195-5p/ITGA2 signalling pathway might be an attractive target for future therapeutic options in NSCLC.

Long Noncoding RNA LINC00899/miR-944/ESR1 Axis Regulates Cervical Cancer Cell Proliferation, Migration, and Invasion

Cervical cancer (CC) is a common malignancy in women. Long noncoding RNA LINC00899 plays a role in cancer, but its effects in CC are unknown. Our experiment aims to investigate the specific effects of LINC00899 in CC. LINC00899 was lowly expressed in CC tissues and cells, and overexpressed LINC0089 inhibited the viability, proliferation, migration, and invasion of CC cells, whereas silencing of LINC00899 had the opposite effect. There is a targeting relationship between LINC0089 and miR-944. It was found that miR-944 could competitively bind with LINC00899, and LINC00899 in turn, could downregulate expression of miR-944. Moreover, estrogen receptor 1 (ESR1) was the target gene of miR-944. Overexpressed miR-944 inhibited ESR1 expression, yet enhanced the migration and invasion of CC cells and promoted the expression levels of N-cadherin and Vimentin while inhibiting the expression of E-cadherin. However, overexpressed ESR1 reversed the effect of miR-944 overexpression on CC cells. LINC00899/miR-944/ESR1 axis regulates the proliferation, migration, and invasion of CC cells by regulating the expression levels of related proteins.

LINC00511 knockdown suppresses glioma cell malignant progression through miR-15a-5p/AEBP1 axis

BACKGROUND

A strong relationship between long intergenic non-protein coding RNA 511 (LINC00511) and glioma has been previously reported but the mechanism of LINC00511 in glioma is yet to be determined. This study examined the mechanism of LINC00511 in glioma.

METHODS

The expression of LINC00511 in glioma was determined by bioinformatics analysis and real-time quantitative PCR (RT-qPCR) analysis. The target relationship between genes was predicted by starBase, TargetScan, and was verified by dual-luciferase. Subsequently, siRNA targeting LINC00511 (siLINC00511) and miR-15a-5p mimic were transfected into glioma cells to examine the effect on biological characteristics using cell counting kit-8, clone formation, flow cytometry, wound-healing, and transwell. MiR-15a-5p inhibitor and AEBP1 were used for in vitro rescue experiments, and tumorigenesis assay and immunohistochemical assays were performed for in vivo experiments. Epithelial-mesenchymal transition (EMT) and p65 phosphorylation were examined by Western blot.

RESULTS

LINC00511 was predicted and verified to be up-regulated in glioma. SiLINC00511 suppressed cell viability, proliferation, migration and invasion, accelerated apoptosis of glioma cells. Mechanically, siLINC00511 promoted E-cadherin expression but suppressed N-cadherin and Snail expressions. MiR-15a-5p bound to LINC00511, and miR-15a-5p inhibitor partially reversed the effect and regulation of siLINC00511 on glioma cells. AEBP1, a target gene of miR-15a-5p, could activate p65 phosphorylation to promote EMT protein expression and partially reverse the inhibitory effect of miR-15a-5p mimic on the malignant phenotype of glioma cells. SiLINC00511 inhibited tumor growth, down-regulated miR-15a-5p expression and up-regulated AEBP1 and Ki67 expressions in vivo.

CONCLUSION

LINC00511 knockdown inhibits glioma cell progression via miR-15a-5p/AEBP1 axis.

Investigation and verification of the clinical significance and perspective of natural killer group 2 member D ligands in colon adenocarcinoma

This study investigated and verified the diagnostic and prognostic values of natural killer group 2 member D ligand (NKG2DL) genes in colon adenocarcinoma (COAD). We downloaded NKG2DLs expression data and corresponding clinical parameters from The Cancer Genome Atlas (TCGA) and used bioinformatics techniques to investigate the values of NKG2DLs in COAD. Then, we used the GSE40967 cohort to verify the prognostic value of NKG2DLs. Finally, we verified the ULBP2 expression level in tissues, and also investigated the diagnostic and prognostic values of ULBP2 in COAD. The diagnostic receiver operating characteristic curves showed that ULBP1, ULBP2, ULBP3, and RAET1L had high diagnostic values in COAD [Area Under Curve (AUC) > 0.9]. In TCGA cohort, the univariate and multivariate survival analyses suggested that ULBP2 was correlated with the prognosis of COAD recurrence-free survival (RFS) and overall survival (OS). In GSE40967 cohort, ULBP2 was associated with CC RFS and OS. Reverse transcription-quantitative polymerase chain reaction and immunohistochemistry results showed that ULBP2 was highly expressed in COAD tumor tissues (P < 0.05) and both had diagnostic values (AUC > 0.7). Validated survival analysis showed that the high expression of ULBP2 had a worse prognosis in COAD OS and RFS. Thus, ULBP2 might be an independent diagnostic and prognostic biomarker of COAD.

Long non‑coding RNA LINC00491 promotes proliferation and inhibits apoptosis in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is a common malignant tumor in the human digestive system, which affects the physical and mental health of the patient. Long non‑coding (lnc)RNAs have been revealed to play an important role in human malignant tumors. Moreover, long intergenic non‑protein coding RNA 491 (LINC00491) is a newly discovered lncRNA that can affect the prognosis of cancer. The present study aimed to explore the expression of LINC00491 in ESCC tissues and cells. The reverse transcription‑quantitative PCR results suggested that LINC00491 was upregulated in ESCC tissues and cells. LINC00491 expression in esophageal squamous cell carcinoma cells were knocked down. Cell Counting Kit‑8, wound healing, Transwell and apoptosis assays were performed to detect the effects of LINC00491 knockdown on cell biological behavior. The results showed that lower expression of LINC00491 resulted in decreased cell proliferation and migration and increased the apoptosis rate. Therefore, the present results indicated that lncRNA LINC00491 promoted the biological processes of ESCC, and thus LINC00491 may be a potential therapeutic target for ESCC.

LncRNA TINCR favors tumorigenesis via STAT3-TINCR-EGFR-feedback loop by recruiting DNMT1 and acting as a competing endogenous RNA in human breast cancer

The long noncoding RNA (lncRNA) TINCR has recently been found to be associated with the progression of human malignancies, but the molecular mechanism of TINCR action remains elusive, particularly in breast cancer. The oncogenic role of TINCR was examined in vitro and in vivo in breast cancer. Next, the interaction between TINCR, DNMT1, and miR-503-5p methylation was explored. Moreover, the mechanism by which TINCR enhances EGFR expression and downstream signaling via an RNA–RNA interaction was comprehensively investigated. Furthermore, upstream transcriptional regulation of TINCR expression by STAT3 was examined by performing chromatin immunoprecipitation. Finally, feedback signaling in the STAT3–TINCR–EGFR downstream cascade was also investigated. TINCR is upregulated in human breast cancer tissues, and TINCR knockdown suppresses tumorigenesis in vitro and in vivo. Mechanistically, TINCR recruits DNMT1 to the miR-503-5p locus promoter, which increases the methylation and suppresses the transcriptional expression of miR-503-5p. Furthermore, TINCR also functions as a competing endogenous RNA to upregulate EGFR expression by sponging miR-503-5p. In addition, TINCR stimulates JAK2–STAT3 signaling downstream from EGFR, and STAT3 reciprocally enhances the transcriptional expression of TINCR. Our findings broaden the current understanding of the diverse manners in which TINCR functions in cancer biology. The newly identified STAT3–TINCR–EGFR-feedback loop could serve as a potential therapeutic target for human cancer.

Non-Coding RNAs: Uncharted Mediators of Thyroid Cancer Pathogenesis

Thyroid cancer is the most prevalent malignancy of the endocrine system and the ninth most common cancer globally. Despite the advances in the management of thyroid cancer, there are critical issues with the diagnosis and treatment of thyroid cancer that result in the poor overall survival of undifferentiated and metastatic thyroid cancer patients. Recent studies have revealed the role of different non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) that are dysregulated during thyroid cancer development or the acquisition of resistance to therapeutics, and may play key roles in treatment failure and poor prognosis of the thyroid cancer patients. Here, we systematically review the emerging roles and molecular mechanisms of ncRNAs that regulate thyroid tumorigenesis and drug response. We then propose the potential clinical implications of ncRNAs as novel diagnostic and prognostic biomarkers for thyroid cancer.

Long-Chain Non-Coding SOX21-AS1 Promotes Proliferation and Migration of Breast Cancer Cells Through the PI3K/AKT Signaling Pathway

Aim

This study aimed to investigate the effect of long-chain non-coding SOX21-AS1 on the proliferation and migration of breast cancer (BC) cells through the PI3K/AKT signaling pathway.

Methods

Eighty-eight BC and adjacent tissues were collected, and BC cells and normal breast epithelial cells were purchased. LncRNA SOX21-AS1 expression in tissues and cells was detected by RT-PCR. miR-NC, si-SOX21-AS1, and Sh-SOX21-AS1 were transfected into BC cells. The PI3K/AKT signaling pathway was interfered with L740Y-P (activator of the PI3K/AKT pathway) and LY294002 (inhibitor of the PI3K/AKT pathway) in BC cells. The SOX21-AS1 expression in BC tissues and cells was tested by qRT-PCR, and the expression levels of p-PI3K, p-AKT, N-cadherin, E-cadherin, and vimentin were detected by WB.

Results

SOX21-AS1 was highly expressed in BC, and the p-PI3K and p-AKT levels were also high. Cell experiments showed that inhibiting SOX21-AS1 expression could inhibit the proliferation, invasion, migration, and EMT of BC cells, and up-regulating its expression could promote the proliferation, invasion, migration, and EMT of ovarian cancer cells. The tumor-forming experiment in nude mice was consistent with the results in vitro. 740Y-P intervention could reverse the inhibition effect of Si-SOX21-AS1 on BC cell proliferation, invasion, migration, and EMT, while LY294002 intervention could reverse the promotion effect of Sh-SOX21-AS1 on BC cell proliferation, invasion, migration, and EMT.

Conclusion

SOX21-AS1 is highly expressed in BC tissues. Silencing BC expression can inhibit the proliferation, invasion, migration, and EMT of cells by inhibiting the PI3K/AKT signaling pathway, which may be a new target for diagnosis and treatment.

Biomarker Discovery for the Carcinogenic Heterogeneity Between Colon and Rectal Cancers Based on lncRNA-Associated ceRNA Network Analysis

Background

Colorectal cancer (CRC) is one of the leading causes of cancer death worldwide. Emerging evidence has revealed that risk factors and metastatic patterns differ greatly between colon and rectal cancers. However, the molecular mechanism underlying their pathogenic differences remains unclear. Therefore, we here aimed to identify non-coding RNA biomarkers based on lncRNA-associated ceRNA network (LceNET) to elucidate the carcinogenic heterogeneity between colon and rectal cancers.

Methods

A global LceNET in human was constructed by employing experimental evidence-based miRNA-mRNA and miRNA-lncRNA interactions. Then, four context-specific ceRNA networks related to cancer initiation and metastasis were extracted by mapping differentially expressed lncRNAs, miRNAs and mRNAs to the global LceNET. Notably, a novel network-based bioinformatics model was proposed and applied to identify lncRNA/miRNA biomarkers and critical ceRNA triplets for understanding the carcinogenic heterogeneity between colon and rectal cancers. Moreover, the identified biomarkers were further validated by their diagnostic/prognostic performance, expression pattern and correlation analysis.

Results

Based on network modeling, lncRNA KCNQ1OT1 (AUC>0.85) and SNHG1 (AUC>0.94) were unveiled as common diagnostic biomarkers for the initiation and metastasis of colon and rectal cancers. qRT-PCR analysis uncovered that these lncRNAs had significantly higher expression level in CRC cell lines with high metastatic potential. In particular, KCNQ1OT1 and SNHG1 function in colon and rectal cancers via different ceRNA mechanisms. For example, KCNQ1OT1/miR-484/ANKRD36 axis was involved in the initiation of colon cancer, while KCNQ1OT1/miR-181a-5p/PCGF2 axis was implicated in the metastasis of rectal cancer; the SNHG1/miR-484/ORC6 axis played a role in colon cancer, while SNHG1/miR-423-5p/EZH2 and SNHG1/let-7b-5p/ATP6V1F axes participated in the initiation and metastasis of rectal cancer, respectively. In these ceRNA triplets, miR-484, miR-181a-5p, miR-423-5p and let-7b-5p were identified as miRNA biomarkers with excellent distinguishing ability between normal and tumor tissues, and ANKRD36, PCGF2, EZH2 and ATP6V1F were closely related to the prognosis of corresponding cancer.

Conclusion

The landscape of lncRNA-associated ceRNA network not only facilitates the exploration of non-coding RNA biomarkers, but also provides deep insights into the oncogenetic heterogeneity between colon and rectal cancers, thereby contributing to the optimization of diagnostic and therapeutic strategies of CRC.

A novel lncRNA-miRNA-mRNA competitive endogenous RNA network for uveal melanoma prognosis constructed by weighted gene co-expression network analysis

AIMS

Uveal melanoma (UM) is the most common and aggressive intraocular tumor in adults, and long-term survival of UM patients remains poor. Abnormal competitive endogenous RNA (ceRNA) networks promote the initiation and progression of many tumors and may thus serve as useful prognostic indicators. Here, we do a comprehensive analysis of long non-coding RNA (lncRNA)-microRNA (miRNA)-mRNA ceRNA networks as prognostic markers for UM.

MATERIALS AND METHODS

The Cancer Genome Atlas UM dataset was used to identify survival-related mRNA and lncRNA modules through weighted gene co-expression network analysis (WGCNA). Prognostic miRNAs were identified using univariate Cox proportional hazard regression. We then used Cox and least absolute shrinkage and selection operator regression to screen for prognostic hub mRNAs and establish a hub ceRNA network. A nomogram of five hub mRNAs was constructed and Kaplan-Meier survival analysis performed.

KEY FINDINGS

Six mRNA modules were constructed, two of which involved 1490 mRNAs that significantly correlated with survival. Among the three lncRNA modules constructed, one involved 199 survival-related lncRNAs. Five hub prognostic mRNAs were identified and a hub ceRNA network constructed, consisting of six lncRNAs, four miRNAs, and five mRNAs, with high prognostic value.

SIGNIFICANCE

We describe a hub ceRNA network of survival-associated lncRNAs, miRNAs, and mRNA that may underlie a critical post-translational regulatory mechanism determining UM aggression. These hub RNAs may be valuable prognostic markers and therapeutic targets in UM.

Investigating the regulatory function of the ANO1-AS2 on the ANO1 gene in infertile men with asthenozoospermia and terato-asthenozoospermia

Long non-coding RNAs (lncRNAs) have a particular expression in the testicular tissue and exhibit a regulatory function on the reproduction system. ANO1-AS2 (linc02584), as an lncRNA is located near the anoctamin1 (ANO1) gene. ANO1 is an important component of the transmembrane system exhibiting expression modifications in the idiopathic infertile men. Therefore, the present study was conducted to investigate the relationship between ANO1-AS2 and ANO1 gene expression with sperm motility and morphology in the patients with asthenozoospermia (AZ) and terato- asthenozoospermia (TAZ). The study population included 32 patients with AZ, 35 patients with TAZ, and 34 people with normozoospermia (NZ, control). The expression levels of ANO1 gene and ANO1-AS2 in the spermatozoa were measured by the quantitative real-time polymerase chain reaction (PCR). Docking analysis was performed to investigate the interactions of the ANO1 gene promoter and intermediate elements with ANO1-AS2. ANO1 gene expression was significantly (P < 0.05) downregulated in the patients however; ANO1-AS2 expression was significantly upregulated (P < 0.05). The subsequent analysis confirmed the inverse correlation between ANO1 and ANO1-AS2. ANO1 gene expression level was significantly positively correlated with sperm motility and morphology (P < 0.05). Moreover, ANO1-AS2 expression showed an inverse correlation with sperm motility and morphology (P < 0.05). Docking analysis confirmed that ANO1-AS2 could stably interact with ANO1 gene promoter. In conclusion, ANO1-AS2 is likely to downregulate the ANO1 gene by interacting with ANO1 gene promoter, which can influence the sperm motility and morphology.

Noncoding RNAs in gastric cancer: implications for drug resistance

Gastric cancer is the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. Advanced gastric cancer patients can notably benefit from chemotherapy including adriamycin, platinum drugs, 5-fluorouracil, vincristine, and paclitaxel as well as targeted therapy drugs. Nevertheless, primary drug resistance or acquisition drug resistance eventually lead to treatment failure and poor outcomes of the gastric cancer patients. The detailed mechanisms involved in gastric cancer drug resistance have been revealed. Interestingly, different noncoding RNAs (ncRNAs), such as microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), are critically involved in gastric cancer development. Multiple lines of evidences demonstrated that ncRNAs play a vital role in gastric cancer resistance to chemotherapy reagents and targeted therapy drugs. In this review, we systematically summarized the emerging role and detailed molecular mechanisms of ncRNAs impact drug resistance of gastric cancer. Additionally, we propose the potential clinical implications of ncRNAs as novel therapeutic targets and prognostic biomarkers for gastric cancer.

Prediction of overall survival time in patients with colon adenocarcinoma using DNA methylation profiling of long non-coding RNAs

Long non-coding RNAs (lncRNAs) are a subgroup of RNAs able to regulate gene expression at the epigenetic level, and are therefore central to the regulation of numerous biological processes and the progression of multiple cancer types. However, lncRNAs have not been identified to considerably influence overall survival (OS) outcome in numerous different types of cancer. The majority of studies investigating the association between lncRNAs and epigenetic regulation have focused on their altered expression levels in cancerous cells, and few studies have focused on determining the correlation between lncRNAs and OS time. In the present study, comprehensive lncRNA expression analysis was performed on a cohort of patients diagnosed with colon adenocarcinoma (COAD) using the least absolute shrinkage and selection operator method (LASSO). Subsequently, the construction of a prognostic methylation-based predictive system was performed based on the results of LASSO analysis. Functional enrichment analysis of lncRNA co-expression genes was also performed. According to the results of the present study, the classifier was able to significantly predict the prognosis of patients with COAD, and the investigation of the relevant elucidated genes further revealed the mechanism of COAD pathogenesis.

Integrative Analysis of ceRNA Network Reveals Functional lncRNAs in Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is the second most common lethal liver cancer worldwide. Currently, despite the latest developments in genomics and transcriptomics for ICC in recent years, the molecular pathogenesis promoting ICC remains elusive, especially in regulatory mechanisms of long noncoding RNAs (lncRNAs), which acts as competing endogenous RNA (ceRNA). In order to elucidate the molecular mechanism of functional lncRNA, expression profiles of lncRNAs, microRNAs (miRNAs), and messenger RNAs (mRNAs) were obtained from The Cancer Genome Atlas (TCGA) database and an integrative analysis of the ICC-associated ceRNA network was performed. Moreover, gene oncology enrichment analyses for the genes in the ceRNA network were implemented and novel prognostic biomarker lncRNA molecules were identified. In total, 6,738 differentially expressed mRNAs (DEmRNAs), 2,768 lncRNAs (DElncRNAs), and 173 miRNAs (DEmiRNAs) were identified in tumor tissues and adjacent nontumor ICC tissues with the thresholds of adjusted P < 0.01 and |logFC| > 2. An ICC-specific ceRNA network was successfully constructed with 30 miRNAs, 16 lncRNAs, and 80 mRNAs. Gene oncology enrichment analyses revealed that they were associated with the adaptive immune response, T cell selection and positive regulation of GTPase activity categories. Among the ceRNA networks, DElncRNAs ARHGEF26-AS1 and MIAT were found to be hub genes in underexpressed and overexpressed networks, respectively. Notably, univariate Cox regression analysis indicated that DElncRNAs HULC significantly correlated with overall survival (OS) in ICC patients (P value < 0.05), and an additional survival analysis for HULC was reconfirmed in an independent ICC cohort from the Gene Expression Omnibus (GEO) database. These findings contribute to a more comprehensive understanding of the ICC-specific ceRNA network and provide novel strategies for subsequent functional studies of lncRNAs in ICC.

The emerging role of microRNAs and long noncoding RNAs in drug resistance of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common malignancy worldwide and the second most lethal human cancer. A portion of patients with advanced HCC can significantly benefit from treatments with sorafenib, adriamycin, 5-fluorouracil and platinum drugs. However, most HCC patients eventually develop drug resistance, resulting in a poor prognosis. The mechanisms involved in HCC drug resistance are complex and inconclusive. Human transcripts without protein-coding potential are known as noncoding RNAs (ncRNAs), including microRNAs (miRNAs), small nucleolar RNAs (snoRNAs), long noncoding RNAs (lncRNAs) and circular RNA (circRNA). Accumulated evidences demonstrate that several deregulated miRNAs and lncRNAs are important regulators in the development of HCC drug resistance which elucidates their potential clinical implications. In this review, we summarized the detailed mechanisms by which miRNAs and lncRNAs affect HCC drug resistance. Multiple tumor-specific miRNAs and lncRNAs may serve as novel therapeutic targets and prognostic biomarkers for HCC.

Cancer-related long noncoding RNAs show aberrant expression profiles and competing endogenous RNA potential in esophageal adenocarcinoma

Long non-coding RNAs (lncRNAs) govern gene expression by competitively binding to microRNA response elements (MREs). Although they were initially considered as transcriptional noise, lncRNAs have attracted increased attention in oncology. Dysregulation of lncRNAs occurs in various types of human tumor, including esophageal adenocarcinoma (EAC). However, the functions of these cancer-associated lncRNAs and of their related competitive endogenous RNA (ceRNA) network in EAC remains unknown. To determine the relevant potential mechanisms, the present study analyzed the transcriptome sequencing data and clinical information of 79 patients with EAC, including 79 tumor samples and 11 normal samples, which were obtained from The Cancer Genome Atlas esophageal cancer project. The edgeR v3.25.0 software was used for differential gene expression analysis. The results exhibited 561 cancer-associated lncRNAs with a >2.0-fold change and a false discovery rate-adjusted P<0.01. Among these lncRNAs, 26 were significantly associated with patient overall survival. According to data from bioinformatics databases and differentially expressed RNAs, an lncRNA-regulated ceRNA network for EAC was constructed. The results demonstrated that the aberrantly expressed lncRNA-associated ceRNA network included 37 EAC cancer-associated lncRNAs, five miRNAs and 13 mRNAs. In conclusion, the present study identified novel lncRNAs as candidate prognostic biomarkers and revealed a potential regulatory network of gene expression in EAC.

LINC00491 as a new molecular marker can promote the proliferation, migration and invasion of colon adenocarcinoma cells

Background

Long non-coding RNAs (lncRNAs) play an important role in the pathogenesis of multiple tumors. However, the roles of lncRNAs during colon adenocarcinoma and cancer progression remain unclear. This study aimed identify new lncRNAs that act as molecular markers for the prevention and diagnosis of colon adenocarcinoma.

Methods

RNA sequencing (RNA-Seq) data associated with colon adenocarcinoma were retrieved from the Cancer Genome Atlas (TCGA). Biological processes in Gene Ontology (Go) and the Kyoto Encyclopedia of Genomes (KEGG) were searched for pathways at the significance level. The expression of LINC00491 and its downstream targets were assessed by real-time PCR, Western blotting and dual-luciferase assays. Biological functions of LINC00491 during cell proliferation, migration and invasion were assessed using CCK-8, colony formation assays, wound healing, and transwell invasion assays in colon adenocarcinoma HT-29 and HCT116 cells.

Results

Bioinformatics analysis with the TCGA colon adenocarcinoma dataset showed that LINC00491 was significantly up-regulated in colon adenocarcinoma. Furthermore, we found that LINC00491 positively regulates SERPINE1 expression through sponging miR-145 and promoting the proliferation, migration, and invasion of colon adenocarcinoma cells, thus playing an oncogenic role during colon adenocarcinoma pathogenesis.

Conclusion

LINC00491 functions as a ceRNA to promote SERPINE1 expression by sponging miR-145. LINC00491 serves as a therapeutic target and prognostic biomarker in colon adenocarcinoma.

SOX21-AS1 is associated with clinical stage and regulates cell proliferation in nephroblastoma

LncRNA SOX21 antisense RNA 1 (SOX21-AS1) dysregulated in many types of human cancer, and functioned as tumor suppressor or promoter depending on tumor types. However, there was no report about the role of SOX21-AS1 in nephroblastoma. In the present study, we first found that SOX21-AS1 expression was elevated in nephroblastoma tissues and cell lines compared with adjacent normal tissues and normal human embryonic kidney cell line, respectively. Moreover, we observed nephroblastoma patients with large tumor size, advanced National Wilms Tumor Study (NWTS) stage or unfavorable histopathological type, and patients that had higher SOX21-AS1 expression levels than nephroblastoma patients with small tumor size, early NWTS stage or favorable histopathological type. The in vitro studies suggested that knockdown of SOX21-AS1 suppressed nephroblastoma cell proliferation and colony formation, and induced cell-cycle arrest through up-regulating p57 expression. In conclusion, our study suggests that SOX21-AS1 functions as oncogenic lncRNA in nephroblastoma, which may provide a novel insight for nephroblastoma carcinogenesis.