Comprehensive analysis of aberrantly expressed profiles of lncRNAs, miRNAs and mRNAs with associated ceRNA network in cholangiocarcinoma

Exosomal linc00152 intensifies the crosstalk between cholangiocarcinoma cells and cancer-associated fibroblasts

INTRODUCTION AND OBJECTIVES

Cholangiocarcinoma is a highly lethal carcinoma. Exosomes derived from cancer-associated fibroblasts (CAFs) serve key roles in the crosstalk between CAFs and cancer cells. Exploring the roles of CAF-derived exosomes and the mechanisms contribute to a better understanding of the development of cholangiocarcinoma.

MATERIALS AND METHODS

Carcinoma and para-carcinoma tissues were collected from patients. Exosomes were isolated from CAFs and characterized by transmission electron microscopy, dynamic light scattering and western blot. Cholangiocarcinoma cells were cocultured with CAF-derived exosomes, and its proliferation, migration and invasion were evaluated with CCK-8, EdU incorporation and transwell assays, respectively. The interaction between a long non-coding RNA linc00152 and an RNA-binding protein hnRNPA2B1 was determined with RNA immunoprecipitation and RNA pull-down. The ubiquitination of hnRNPA2B1 was examined with western blot.

RESULTS

Linc00152 was highly expressed in cholangiocarcinoma tissues and cells, and its increased expression was associated with advanced tumor stage and poor prognosis. Linc00152 was highly enriched in CAFs and CAF-derived exosomes. CAF-derived exosomes promoted cholangiocarcinoma cell proliferation, migration, and invasion by delivering linc00152. Further analysis showed that hnRNPA2B1 recruited linc00152 and enhanced its loading into exosomes. The interaction between hnRNPA2B1 and linc00152 was identified, and linc00152 repressed the proteasome-dependent degradation of hnRNPA2B1 in cholangiocarcinoma cells. The oncogenic activities of linc00152 in cholangiocarcinoma cells were dependent on hnRNPA2B1 upregulation.

CONCLUSIONS

CAF-derived exosomes harboring linc00152 enhance malignancy in cholangiocarcinoma, identifying a novel role of exosomal linc00152 for intensifying the crosstalk between CAFs and cholangiocarcinoma cells.

Advances in omics-based biomarker discovery for biliary tract malignancy Diagnosis:A narrative review

Biliary tract neoplasms, which originate from the intrahepatic or extrahepatic biliary epithelium, are relatively rare but diagnostically challenging types of tumours, and their morbidity and mortality have increased in recent years. Due to ineffective early diagnostic methods, once detected, patients are in an advanced stage with a poor prognosis and few treatment options. With the development of omics technologies, the associations between microorganisms, bile acid and salts, noncoding RNAs and biliary tract malignancies have been gradually revealed, providing new methods for the discovery of diagnostic biomarkers. Here, we review the research advances in microbiomics, transcriptomics, metabolomics, and proteomics in the discovery of diagnostic biomarkers for biliary tract malignancies.

Single-Nucleus RNA-Seq Characterizes the Cell Types Along the Neuronal Lineage in the Adult Human Subependymal Zone and Reveals Reduced Oligodendrocyte Progenitor Abundance with Age

The subependymal zone (SEZ), also known as the subventricular zone (SVZ), constitutes a neurogenic niche that persists during postnatal life. In humans, the neurogenic potential of the SEZ declines after the first year of life. However, studies discovering markers of stem and progenitor cells highlight the neurogenic capacity of progenitors in the adult human SEZ, with increased neurogenic activity occurring under pathological conditions. In the present study, the complete cellular niche of the adult human SEZ was characterized by single-nucleus RNA sequencing, and compared between four youth (age 16-22) and four middle-aged adults (age 44-53). We identified 11 cellular clusters including clusters expressing marker genes for neural stem cells (NSCs), neuroblasts, immature neurons, and oligodendrocyte progenitor cells. The relative abundance of NSC and neuroblast clusters did not differ between the two age groups, indicating that the pool of SEZ NSCs does not decline in this age range. The relative abundance of oligodendrocyte progenitors and microglia decreased in middle-age, indicating that the cellular composition of human SEZ is remodeled between youth and adulthood. The expression of genes related to nervous system development was higher across different cell types, including NSCs, in youth as compared with middle-age. These transcriptional changes suggest ongoing central nervous system plasticity in the SEZ in youth, which declined in middle-age.

LncRNA Zfas1 boosts cell apoptosis and autophagy in myocardial injury induced by hypoxia via miR-383-5p/ATG10 axis

Background

Myocardial injury has been regarded as a major cause of several heart diseases. Long non-coding RNA (lncRNA) has emerged as a key regulator in a wide array of diseases.

Aim of the study

This study aims to explore the role of Zfas1 in myocardial injury.

Methods

3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was adopted to evaluate the proliferative capability of H9c2 cells. Terminal deoxynucleotidyltransferase dUTP nick end labeling (TUNEL) and flow cytometry assays were employed to measure cell apoptosis. The expression of proteins related to apoptosis and autophagy was examined by Western blot. Immunofluorescence (IF) assay was performed to monitor the process of autophagy. Real-time reverse-transcription polymerase chain reaction (RT-qPCR) was employed to determine the expressions of autophagy-related gene 10 (ATG10), miR-383-5p and Zfas1. The interacting relationship between miR-383-5p and ATG10 (or Zfas1) was assessed by luciferase reporter and RNA-binding protein immunoprecipitation (RIP) assays.

Results

The treatment of hypoxia hindered cell proliferation but accelerated cell apoptosis and autophagy. ATG10 exhibited higher mRNA and protein expression in H9c2 cells induced by hypoxia. MiR-383-5p was revealed to be the upstream gene of ATG10 and could interact with ATG10. Zfas1 was validated to sponge miR-383-5p and positively regulated ATG10 expression. Zfas1 knockdown-mediated cellular proliferation, apoptosis and autophagy phenotypes were counteracted by ATG10 abundance.

Conclusions

LncRNA Zfas1 boosts cell apoptosis and autophagy in myocardial injury induced by hypoxia via miR-383-5p/ATG10 axis, indicating that Zfas1 may be utilized as a therapeutic target for myocardial injury.

The roles of epigenetic regulation in cholangiocarcinogenesis

Cholangiocarcinoma (CCA), a heterogeneous malignancy of bile duct epithelial cells, is characterized by aggressiveness, difficult diagnosis, and poor prognosis due to limited understanding and lack of effective therapeutic strategies. Genetic and epigenetic alterations accumulated in CCA cells can cause the aberrant regulation of oncogenes and tumor suppressors. Epigenetic alterations with histone modification, DNA methylation, and noncoding RNA modulation are associated with the carcinogenesis of CCA. Mutation or silencing of genes by various mechanisms can be a frequent event during CCA development. Alterations in histone acetylation/deacetylation at the posttranslational level, DNA methylation at promoters, and noncoding RNA regulation contribute to the heterogeneity of CCA and drive tumor development. In this review article, we mainly focus on the roles of epigenetic regulation in cholangiocarcinogenesis. Alterations in epigenetic modification can be potential targets for the therapeutic management of CCA, and epigenetic targets may become diagnostic biomarkers of CCA.

Profiling the Spatial Expression Pattern and ceRNA Network of lncRNA, miRNA, and mRNA Associated with the Development of Intermuscular Bones in Zebrafish

Intermuscular bones (IBs) are small spicule-like bones in the muscular septum of fish, which affect their edible and economic value. The molecular mechanism of IB development is still uncertain. Numerous studies have shown that the ceRNA network, which is composed of mRNA, lncRNA, and miRNA, plays an important regulatory role in bone development. In this study, we compared the mRNA, lncRNA, and miRNA expression profiles in different IB development segments of zebrafish. The development of IBs includes two main processes, which are formation and growth. A series of genes implicated in the formation and growth of IBs were identified through gene differential expression analysis and expression pattern analysis. Functional enrichment analysis showed that the functions of genes implicated in the regulation of the formation and growth of IBs were quite different. Ribosome and oxidative phosphorylation signaling pathways were significantly enriched during the formation of IBs, suggesting that many proteins are required to form IBs. Several pathways known to be associated with bone development have been shown to play an important role in the growth of IBs, including calcium, ECM-receptor interaction, Wnt, TGF-β, and hedgehog signaling pathways. According to the targeting relationship and expression correlation of mRNA, lncRNA, and miRNA, the ceRNA networks associated with the growth of IBs were constructed, which comprised 33 mRNAs, 9 lncRNAs, and 7 miRNAs. This study provides new insight into the molecular mechanism of the development of IBs.

L-Fucose inhibits the progression of cholangiocarcinoma by causing microRNA-200b overexpression

BACKGROUND

Cholangiocarcinoma (CCA) is a malignant biliary tract tumor with an extremely poor prognosis. There is an urgent demand to explore novel therapeutic strategies. L-fucose has been confirmed to participate in anti-inflammation and antitumor activities. However, the effect of L-fucose on the progression of CCA has not been well investigated. This study aimed to determine whether L-fucose induced the inhibition of CCA and its possible mechanism.

METHODS

The anti-growth activity was determined using Cell Counting Kit-8 assay, colony formation assays, Annexin V-fluorescein isothiocyanate/propidium iodide (FITC/PI) assay, and cell cycle analysis. The anti-metastasis activity was determined by wound healing, transwell, and invasion assays. The anti-angiogenesis activity was determined by tube formation and transwell assays. MicroRNAs that may be involved in the L-fucose-induced CCA inhibition was analyzed using bioinformatics methods. The preclinical therapeutic efficacy was mainly estimated by ultrasound in xenograft nude mouse models. Differences were analyzed via Student's t test or one-way analysis of variance.

RESULTS

L-Fucose induced apoptosis and G0/G1 cell cycle arrest, inhibited cell epithelial-mesenchymal transition of CCA cells, and additionally inhibited tube formation of human umbilical vein endothelial cells (HUVECs) in a dose-dependent manner, leading to a decrease in cell proliferation, metastasis, and angiogenesis. Mechanistically, L-fucose induced microRNA-200b (miR-200b) upregulation, and mitogen-activated protein kinase 7 (MAPK7) downregulation was found to be targeted by miR-200b, with decreased cell proliferation and metastasis. Additionally, phosphorylated signal transducer and activator of transcription 3 was found to be downregulated after L-fucose treatment. Finally, in vivo experiments in CCA xenograft models also confirmed the antitumor properties of L-fucose.

CONCLUSION

L-Fucose inhibited the progression of CCA via the miR-200b/MAPK7 and signal transducer and activator of transcription 3 signaling pathways.

Identification of a prognosis-related ceRNA network in cholangiocarcinoma and potentially therapeutic molecules using a bioinformatic approach and molecular docking

Cholangiocarcinoma (CCA) is a highly malignant disease with a poor prognosis, and mechanisms of initiation and development are not well characterized. It is long noncoding RNAs (lncRNAs) acting as miRNA decoys to regulate cancer-related RNAs in competing endogenous RNA (ceRNA) networks that suggest a possible molecular mechanism in CCA. The current study aims to find potential prognosis biomarkers and small molecule therapeutic targets based on the construction of a CCA prognosis-related ceRNA network. A transcriptome dataset for CCA was downloaded from the TCGA database. Differentially expressed lncRNAs (DElncRNAs), DEmiRNAs and DEmRNAs were identified based on the differential expression and a DEceRNA network was constructed using predicted miRNA-lncRNA and miRNA-mRNA interactions. Heat maps, PCA analysis, and Pathway enrichment analysis and GO enrichment analysis were conducted. The prognostic risk model and molecular docking were constructed based on identified key ceRNA networks. A DElncRNA-miRNA-mRNAs network consisting of 434 lncRNA-miRNA pairs and 284 miRNA-mRNA pairs with 200 lncRNAs, 21 miRNAs, and 245 mRNAs was constructed. There were three lncRNAs (AC090772.1, LINC00519, and THAP7-AS1) and their downstream mRNAs (MECOM, MBNL3, RCN2) screened out as prognostic factors in CAA. Three key networks (LINC00519/ hsa-mir-22/ MECOM, THAP7-AS1/hsa-mir-155/MBNL3, and THAP7-AS1/hsa-mir-155/RCN2) were identified based on binding sites prediction and survival analysis. A prognostic risk model was established with a good predictive ability (AUC = 0.66–0.83). Four anticancer small molecules, MECOM and 17-alpha-estradiol (−7.1 kcal/mol), RCN2 and emodin (−8.3 kcal/mol), RCN2 and alpha-tocopherol (−5.6 kcal/mol), and MBNL3 and 17-beta-estradiol (−7.1 kcal/mol) were identified. Based on the DEceRNA network and Kaplan–Meier survival analysis, we identified three important ceRNA networks associated with the poor prognosis of CCA. Four anti-cancer small molecules were screened out by computer-assisted drug screening as potential small molecules for the treatment of CCA. This study provides theoretical support for the development of ceRNA network-based drugs to improve the prognosis of CCA.

Identification of Prognostic Factors in Cholangiocarcinoma Based on Integrated ceRNA Network Analysis

This study is aimed at screening prognostic biomarkers in cholangiocarcinoma (CHOL) based on competitive endogenous RNA (ceRNA) regulatory network analysis. Microarray data for lncRNAs, mRNA, and miRNAs were downloaded from the GEO and TCGA databases. Differentially expressed RNAs (DERs) were identified in CHOL and normal liver tissue samples. WGCNA was used to identify disease-related gene modules. By integrating the information from the starBase and DIANA-LncBasev2 databases, we constructed a ceRNA network. Survival analysis was performed, and a prognostic gene-based prognostic score (PS) model was generated. The correlation between gene expression and immune cell infiltration or immune-related feature genes was analyzed using TIMER. Finally, real-time quantitative PCR (RT-qPCR) was used to verify the expression of the 10 DERs with independent prognosis. A large cohort of DERs was identified in the CHOL and control samples. The ceRNA network consisted of 6 lncRNAs, 2 miRNAs, 90 mRNAs, and 98 nodes. Ten genes were identified as prognosis-related genes, and a ten-gene signature PS model was constructed, which exhibited a good prognosis predictive ability for risk assessment of CHOL patients (AUC value = 0.975). Four genes, ELF4, AGXT, ABCG2, and LDHD, were associated with immune cell infiltration and closely correlated with immune-related feature genes (CD14, CD163, CD33, etc.) in CHOL. Additionally, the consistency rate of the RT-qPCR results and bioinformatics analysis was 80%, implying a relatively high reliability of the bioinformatic analysis results. Our findings suggest that the ten-signature gene PS model has significant prognostic predictive value for patients with CHOL. These four immune-related DERs are involved in the progression of CHOL and may be useful prognostic biomarkers for CHOLs.

Identification of Potential Biomarkers of Platelet RNA in Glioblastoma by Bioinformatics Analysis

Objective

Glioblastoma is one of the most common and fatal malignancies in adults. Current treatment is still not optimistic. Glioblastoma (GBM) transports RNA to platelets in the blood system via microvesicles, suggesting that platelet RNA can be a potential diagnostic and therapeutic target. The roles of specific platelet RNAs in treatment of GBM are not well understood.

Methods

Platelet RNA profiling of 8 GBM and 12 normal samples were downloaded from the GEO database. Differentially expressed genes (DEGs) were identified between tumors and normal samples. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to elucidate the functions of up- and downregulated genes. miRNA was predicted by miRTarBase, TargetScan, and miRDB databases. circBase and circBank were used for circRNA prediction. ceRNA (circRNA-mRNA-miRNA) network was constructed to investigate the potential interactions.

Results

22 genes were upregulated and 9 genes were downregulated. There are only two genes (CCR7 and FAM102A) that connect to miRNAs (hsa-let-7a-5p, hsa-miR-1-3p). We assessed the overall survival rates by Kaplan-Meier plotter, and relative expression of GBM and subtypes for overlapped mRNA (CCR7 and FAM102A) were evaluated, and further, we obtained circRNAs (has-circ-0015164, hsa-circ-0003243) by circBank and circBase and bind sites through the CSCD database. Finally, a ceRNA network (circRNA-mRNA-miRNA) was constructed based on 2 miRNAs, 2 mRNAs, and 2 circRNAs by Cytoscape. This study focused on potential mRNA and ceRNA biomarkers to targeted treatment of GBM and provided ideas for clinical treatment through the combination of hematology and oncology.

Conclusion

The findings of this study contribute to better understand the relationship between GBM and the blood system (platelets) and might lay a solid foundation for improving GBM molecule and gene diagnosis and prognosis.

Restoring the epigenetically silenced lncRNA COL18A1-AS1 represses ccRCC progression by lipid browning via miR-1286/KLF12 axis

Abnormal accumulation of lipids has been highlighted in the progression of clear cell renal cell carcinoma (ccRCC). However, the underlying mechanism remains unclear. Emerging evidence suggests long noncoding RNAs (lncRNAs) participate in the regulation of lipid metabolism. In this study, we found lncRNA COL18A1-AS1 was downregulated in ccRCC and that higher COL18A1-AS1 expression indicated better prognosis. Decreased COL18A1-AS1 expression was caused by DNA methylation at the CpG islands within its promoter. Restoring the epigenetically silenced COL18A1-AS1 repressed tumor progression, promoted lipid browning and consumption in vitro and in vivo. Mechanistically, COL18A1-AS1 could competitively bind miR-1286 to increase the expression of Krüppel-like factor 12 (KLF12). Downregulation of COL18A1-AS1 in ccRCC resulted in the low expression of KLF12. COL18A1-AS1/KLF12 positively regulated uncoupling protein 1 (UCP1)-mediated lipid browning, which promotes tumor cell "slimming" and inhibits tumor progression. When tumor cell "slimming" occurred, lipid droplets turned into tiny pieces, and lipids were consumed without producing ATP energy. Taken together, our findings on COL18A1-AS1-miR-1286/KLF12 axis revealed a potential mechanism of abnormal accumulation of lipids in ccRCC and could be a promising therapeutic target for ccRCC patients.

Metabolome and Whole-Transcriptome Analyses Reveal the Molecular Mechanisms Underlying Hypoglycemic Nutrient Metabolites Biosynthesis in Cyclocarya paliurus Leaves During Different Harvest Stages

Cyclocarya paliurus, a well-known nutrient and beverage plant, is under development for use in functional health care products best and natural and organic foods. We hypothesis that the composition and metabolic accumulation of hypoglycemic nutrient metabolites exhibit significant differences depending on harvest time. Therefore, it is of great significance to establish the best harvest time for C. paliurus leaves for the further development of healthy teas and other products. However, the detail compositions and molecular mechanisms of nutrients biosynthesis in C. paliurus leaves during different harvest stages remain largely unclear. Metabolome analysis showed that a suitable leaf-harvesting strategy for C. paliurus could be in September or October each year due to the high content of hypoglycemic nutrient metabolites. We found that two of the seven differentially accumulated phenolic acid metabolites have a relatively good inhibitory effect on α-amylase, indicating that they may play a role in the hypoglycemic function. Combined analysis of coexpression, ceRNA network, and weighted gene correlation network analysis (WGCNA) showed that several genes or transcription factors (TFs) in three modules correlated highly with hypoglycemic nutrient metabolites, including CpPMM, CpMan, CpFK, CpSUS, CpbglX, Cp4CL, CpHCT, and CpWRKY1. These findings help in the understanding of the molecular mechanisms and regulatory networks of the hypoglycemic nutrient metabolites in C. paliurus leaves which are dependent on harvest time and provide theoretical guidance in the development of functional health care products and foods from C. paliurus.

Long non-coding RNA LINC00514 promotes the proliferation and invasion through the miR-708-5p/HOXB3 axis in cervical squamous cell carcinoma

Long non-coding RNA (lncRNA) LINC00514 is a cancer-related lncRNA that has been proven to be implicated in the progression of several cancers. However, the biological function of LINC00514 in cervical squamous cell carcinoma (CSCC) remains unclear. Thus, we aimed to identify the LINC00514 expression profile in CSCC and determine its exact mechanism. Our results showed that the expression of LINC00514 was up-regulated in human CSCC tissues and cell lines. Knockdown of LINC00514 significantly inhibited the proliferation and invasion of CSCC cells, as well as suppressed tumorigenesis of CSCC in vivo. In addition, LINC00514 was found to work as a miRNA sponge for miR-708-5p and suppressed the expression of miR-708-5p in CSCC cells. Homeobox B3 (HOXB3) was found to be a target gene of miR-708-5p. Rescue assays demonstrated that miR-708-5p inhibitor attenuated the effects of LINC00514 knockdown on cell proliferation and invasion in CSCC cells. In addition, overexpression of HOXB3 reversed the inhibitory effects of miR-708-5p mimics on cell proliferation and invasion. Taken together, our findings for the first time elucidated that lncRNA LINC00514 promotes the proliferation and invasion through the miR-708-5p/HOXB3 axis in CSCC. Thus, LINC00514/miR-708-5p/HOXB3 axis might be a promising therapeutic target for the treatment of CSCC.

Protein profiling reveals potential isomiR-associated cross-talks among RNAs in cholangiocarcinoma

Cholangiocarcinomas (CCAs) are tumors that arise from the cholangiocytes. Although some genes have been shown with important roles in pathological process, interactions or cross-talks among different RNAs are important to understand the detailed molecular mechanisms in cancer development, especially discussing cross-talks among isomiRs and other RNAs. Herein, to characterize crucial genes in CCA, the protein expression profile was performed to survey potential crucial mRNAs and related non-coding RNAs (ncRNAs) in mRNA-ncRNA network, mainly including miRNAs/isomiRs and lncRNAs. Deregulated mRNAs were firstly obtained if consistent expression patterns were found at protein and mRNA levels, and related miRNAs/isomiRs were screened according to regulatory relationships. Diverse isomiRs from a given miRNA locus also contributed to interactions between the small RNAs and target mRNAs, and miRNAs were further used to survey related lncRNAs to expand the interactions. Thus, several groups of RNAs were constructed as candidate competitive endogenous RNA (ceRNA) networks. Finally, we found that RAB11FIP1:miR-101-3p:MIR3142HG may be a potential ceRNA network, and the interactions among them may be more complex due to variety of isomiRs. Simultaneously, RAB11FIP1 and miR-194-5p were also detected other related lncRNAs (FBXL19-AS1, SNHG1 and PVT1) that may be crucial in coding-non-coding RNA regulatory network. Our results show that diverse isomiRs with sequence and expression heterogeneities contribute to ceRNA regulatory network that may have crucial roles in CCA, which will expand our understanding of interactions among diverse RNAs and their contributions in cancer development.

Long noncoding RNA LINC00184 facilitates the proliferation, metastasis, and adenine metabolism of cholangiocarcinoma via modulating hsa-miR-23b-3p/ANXA2 axis

The purpose of this article was to probe the mechanism underlying long noncoding RNA (lncRNA)-LINC00184 in cholangiocarcinoma development and to investigate the effects of LINC00184 on cholangiocarcinoma. We used bioinformatics to analyze the expression of LINC00184, microRNA (miR)-23b-3p and ANXA2 in cholangiocarcinoma tissues. The levels of LINC00184, miR-23b-3p, and ANXA2 were detected by qRT-PCR. Cell proliferation was tested by CCK8. Transwell assay was used to detect cell invasion and migration. The target connection between LINC00184, miR-23b-3p, or ANXA2 was probed by luciferase reporter assay. RNA pull-down method was employed to test the relationship among LINC00184/miR-23b-3p/ANXA2 in cholangiocarcinoma cells. The Pearson correlation coefficient analyzed was applied to analyze the correlation among LINC00184, miR-23b-3p, and ANXA2. LC-MS/M analysis was used to explore whether the changes of adenine metabolism was affected by LINC00184 in cholangiocarcinoma cells. We discovered that LINC00184 expression was heightened in cholangiocarcinoma patients and cells. Knockdown of LINC00184 repressed cell proliferation, invasion, migration and adenine metabolism in cholangiocarcinoma cells. miR-23b-3p was regarded as a target of LINC00184 and its depletion perversed the inhibitive influence of LINC00184 silencing on cholangiocarcinoma cells. ANXA2 was a target of miR-23b-3p and was negatively modulated by miR-23b-3p. Moreover, ANXA2 was positively modulated by LINC00184 via sponging miR-23b-3p. In short, silencing of LINC00184 suppressed cell proliferation, invasion and migration through over-expression of miR-23b-3p and reducing of ANXA2 in cholangiocarcinoma cells. These findings contribute to understanding the influences of LINC00184, miR-23b-3p, and ANXA2 on cholangiocarcinoma and provide basis for cholangiocarcinoma treatment.

Emerging roles of long noncoding RNAs in cholangiocarcinoma: Advances and challenges

Cholangiocarcinoma (CCA), a cancer with a relatively low incidence rate, is usually associated with poor prognosis. Current modalities for the diagnosis and treatment of CCA patients are still far from satisfactory. In recent years, numerous long noncoding RNAs (lncRNAs) have been identified as crucial players in the development of various cancers, including CCA. Abnormally expressed lncRNAs in CCA, regulated by some upstream molecules, significantly influence the biological behavior of tumor cells and are involved in tumor development through various mechanisms, including interactions with functional proteins, participation in competing for endogenous RNA (ceRNA) regulatory networks, activation of cancer‐related signaling pathways and epigenetic modification of gene expression. Furthermore, several lncRNAs are closely associated with the clinicopathological features of CCA patients, and are promising biomarkers for diagnosing and prognostication of CCA. Some of these lncRNAs play an important role in chemotherapy drug resistance. In addition, lncRNAs have also been shown to be involved in the inflammation microenvironment of CCA and malignant outcome of CCA risk factors, such as cholestatic liver diseases. In view of the difficulty of diagnosing CCA, more attention should be paid to detectable lncRNAs in the serum or bile. This review summarizes the recent knowledge on lncRNAs in CCA and provides a new outlook on the molecular mechanisms of CCA development from the perspective of lncRNAs. Moreover, we also discussed the limitations of the current studies and differential expression of lncRNAs in different types of CCA.

Competing Endogenous RNAs, Non-Coding RNAs and Diseases: An Intertwined Story

MicroRNAs (miRNAs), a class of small non-coding RNA molecules, are responsible for RNA silencing and post-transcriptional regulation of gene expression. They can mediate a fine-tuned crosstalk among coding and non-coding RNA molecules sharing miRNA response elements (MREs). In a suitable environment, both coding and non-coding RNA molecules can be targeted by the same miRNAs and can indirectly regulate each other by competing for them. These RNAs, otherwise known as competing endogenous RNAs (ceRNAs), lead to an additional post-transcriptional regulatory layer, where non-coding RNAs can find new significance. The miRNA-mediated interplay among different types of RNA molecules has been observed in many different contexts. The analyses of ceRNA networks in cancer and other pathologies, as well as in other physiological conditions, provide new opportunities for interpreting omics data for the field of personalized medicine. The development of novel computational tools, providing putative predictions of ceRNA interactions, is a rapidly growing field of interest. In this review, I discuss and present the current knowledge of the ceRNA mechanism and its implications in a broad spectrum of different pathologies, such as cardiovascular or autoimmune diseases, cancers and neurodegenerative disorders.

Whole-Transcriptome Sequencing Identifies Key Differentially Expressed mRNAs, miRNAs, lncRNAs, and circRNAs Associated with CHOL

To systematically evaluate the whole-transcriptome sequencing data of cholangiocarcinoma (CHOL) to gain more insights into the transcriptomic landscape and molecular mechanism of this cancer, we performed whole-transcriptome sequencing based on the tumorous (C) and their corresponding non-tumorous adjacent to the tumors (CP) from eight CHOL patients. Subsequently, differential expression analysis was performed on the C and CP groups, followed by functional interaction prediction analysis to investigate gene-regulatory circuits in CHOL. In addition, The Cancer Genome Atlas (TCGA) for CHOL data was used to validate the results. In total, 2,895 differentially expressed messenger RNAs (dif-mRNAs), 56 differentially expressed microRNAs (dif-miRNAs), 151 differentially expressed long non-coding RNAs (dif-lncRNAs), and 110 differentially expressed circular RNAs (dif-circRNAs) were found in CHOL samples compared with controls. Enrichment analysis on those differentially expressed genes (DEGs) related to miRNA, lncRNA, and circRNA also identified the function of spliceosome. The downregulated hsa-miR-144-3p were significantly enriched in the competing endogenous RNA (ceRNA) complex network, which also included 7 upregulated and 13 downregulated circRNAs, 7 upregulated lncRNAs, and 90 upregulated and 40 downregulated mRNAs. Moreover, most of the DEGs and a few of the miRNAs (such as hsa-miR-144-3p) were successfully validated by TCGA data. The genes involved in RNA splicing and protein degradation processes and miR-144-3p may play fundamental roles in the pathogenesis of CHOL.

Long Non-Coding RNAs in Biliary Tract Cancer-An Up-to-Date Review

The term long non-coding RNA (lncRNA) describes non protein-coding transcripts with a length greater than 200 base pairs. The ongoing discovery, characterization and functional categorization of lncRNAs has led to a better understanding of the involvement of lncRNAs in diverse biological and pathological processes including cancer. Aberrant expression of specific lncRNA species was demonstrated in various cancer types and associated with unfavorable clinical characteristics. Recent studies suggest that lncRNAs are also involved in the development and progression of biliary tract cancer, a rare disease with high mortality and limited therapeutic options. In this review, we summarize current findings regarding the manifold roles of lncRNAs in biliary tract cancer and give an overview of the clinical and molecular consequences of aberrant lncRNA expression as well as of underlying regulatory functions of selected lncRNA species in the context of biliary tract cancer.

The Potential Regulatory Roles of lncRNAs in DNA Damage Response in Human Lymphocytes Exposed to UVC Irradiation

Long noncoding RNAs (lncRNAs) are a class of noncoding RNAs that modulate gene expression, thereby participating in the regulation of various cellular processes. However, it is not clear about the expression and underlying mechanism of lncRNAs in irradiation-induced DNA damage response. In the present study, we performed integrative analysis of lncRNA-mRNA expression profile in human lymphocytes irradiated with ultraviolet-C (UVC). The results showed that exposure to UVC irradiation dose-dependently increased the fluorescence intensity of γ-H₂AX and induced cell death. Microarray analysis revealed that up-regulated lncRNAs were more common than down-regulated lncRNAs with the increase of radiation dose in UVC-radiated cells. Stem analysis demonstrated the relationship between lncRNA expression level and radiation dose. qPCR results confirmed that LOC338799 and its coexpressed genes such as LCE1F and ISCU showed the increase in expression levels with the increase of UVC radiation dose. We utilized Cytoscape to screen out 5 lncRNAs and 13 coexpressed genes linking to p53, which might participate in the regulation of DNA damage, cell cycle arrest, apoptosis, and cell death. These findings suggest that lncRNAs might play a role in UVC-induced DNA damage response through regulating expression of genes in p53 signaling pathway.

Transcriptomic analysis and identification of prognostic biomarkers in cholangiocarcinoma

Cholangiocarcinoma (CCA) is acknowledged as the second most commonly diagnosed primary liver tumor and is associated with a poor patient prognosis. The present study aimed to explore the biological functions, signaling pathways and potential prognostic biomarkers involved in CCA through transcriptomic analysis. Based on the transcriptomic dataset of CCA from The Cancer Genome Atlas (TCGA), differentially expressed protein-coding genes (DEGs) were identified. Biological function enrichment analysis, including Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, was applied. Through protein-protein interaction (PPI) network analysis, hub genes were identified and further verified using open-access datasets and qRT-PCR. Finally, a survival analysis was conducted. A total of 1,463 DEGs were distinguished, including 267 upregulated genes and 1,196 downregulated genes. For the GO analysis, the upregulated DEGs were enriched in ‘cadherin binding in cell-cell adhesion’, ‘extracellular matrix (ECM) organization’ and ‘cell-cell adherens junctions’. Correspondingly, the downregulated DEGs were enriched in the ‘oxidation-reduction process’, ‘extracellular exosomes’ and ‘blood microparticles’. In regards to the KEGG pathway analysis, the upregulated DEGs were enriched in ‘ECM-receptor interactions’, ‘focal adhesions’ and ‘small cell lung cancer’. The downregulated DEGs were enriched in ‘metabolic pathways’, ‘complement and coagulation cascades’ and ‘biosynthesis of antibiotics’. The PPI network suggested that CDK1 and another 20 genes were hub genes. Furthermore, survival analysis suggested that CDK1, MKI67, TOP2A and PRC1 were significantly associated with patient prognosis. These results enhance the current understanding of CCA development and provide new insight into distinguishing candidate biomarkers for predicting the prognosis of CCA.

Expression of long non-coding RNA ANRIL predicts a poor prognosis in intrahepatic cholangiocarcinoma

BACKGROUND

Intrahepatic cholangiocarcinoma (iCCA) is a deadly cancer worldwide associated with an increased incidence, limited therapeutic options and absence of reliable prognostic biomarkers. Long non-coding RNAs (lncRNA) emerge as relevant biomarkers in cancer being associated with tumor progression. However, lncRNA have been poorly investigated in iCCA.

AIM

To identify lncRNA significantly associated with the survival of patients with iCCA after tumor resection for curative intent.

METHODS

Gene expression profiling and Q-RT-PCR were performed from a cohort of 39 clinically well-annotated iCCA. Univariate Cox proportional hazards model with Wald Statistic was used to identify lncRNA significantly associated with overall (OS) and/or disease-free (DFS) survival.

RESULTS

A signature made of 9 lncRNA was identified to be significantly (P < 0.05) associated with OS and DFS, including 4 lncRNA (lnc-CDK9-1, XLOC_l2_009441, CDKN2B-AS1, HOXC13-AS) highly expressed in poor prognosis iCCA and 5 lncRNA (lnc-CCHCR1-1, lnc-AF131215.3.1, lnc-CBLB-5, COL18A1-AS2, lnc-RELL2-1) highly expressed in better prognosis iCCA. We further validated CDKN2B-AS1 (ANRIL) as a poor prognosis biomarker, not only in iCCA, but also in hepatocellular carcinoma, kidney renal clear cell carcinoma and uterine corpus endometrial carcinoma.

CONCLUSIONS

We report a prognosis lncRNA signature in iCCA and the clinical relevance of CDKN2B-AS1 (ANRIL) overexpression in several cancers.

Comprehensive analysis of competing endogenous RNA network and 3-mRNA signature predicting survival in papillary renal cell cancer

Long non-coding RNAs (lncRNAs) can act as competing endogenous RNAs (ceRNAs) to exert significant roles in regulating the expression of mRNAs by sequestering and binding miRNAs. To elucidate the functional roles and regulatory mechanism of lncRNAs in papillary renal cell cancer (pRCC), we conducted a comprehensive analysis of ceRNA network and constructed a mRNA signature to predict prognosis of pRCC.We collected mRNAs and lncRNAs expression profiles of 289 pRCC samples and 32 normal renal tissues, and miRNA expression profiles of 292 pRCC samples and 34 normal samples from The Cancer Genome Atlas (TCGA) database. Differential expressions of RNAs were evaluated by the "edgeR" package in R. Functional enrichment analysis of DEmRNA was performed by DAVID 6.8 and KEGG, while PPI network of top 200 DEmRNAs was conducted using the STRING database. The univariate and multivariate Cox regression were conducted to figure out the candidate DEmRNAs with predictive values in prognosis. Receiver operator characteristic (ROC) curve estimation was performed to achieve the area under the curve (AUC) of the ROC curve to judge mRNA-associated prognosic model. A ceRNA network was established relying on the basis of combination of lncRNA-miRNA interactions and miRNA-mRNA interactions.A total of 1928 DEmRNAs, 981 DElncRNAs, and 52 DEmiRNAs were identified at significance level of |log2Fold Change |>2 and adjusted P-value < .01. A 3-mRNA signatures consisting of ERG, RRM2, and EGF was constructed to predict survival in pRCC. Moreover, a pRCC-associated ceRNA network was constructed, with 57 lncRNAs, 11 miRNAs, and 28 mRNAs.Our study illustrated the regulatory mechanism of ceRNA network in papillary renal cancer. The identified mRNA signatures could be used to predict survival of pRCC.

A Simple Competing Endogenous RNA Network Identifies Novel mRNA, miRNA, and lncRNA Markers in Human Cholangiocarcinoma

Background

Cholangiocarcinoma (CCA) is the second most common malignant primary liver tumor and has shown an alarming increase in incidence over the last two decades. However, the mechanisms behind tumorigenesis and progression remain insufficient. The present study aimed to uncover the underlying regulatory mechanism on CCA and find novel biomarkers for the disease prognosis.

Method

The RNA-sequencing (RNA-seq) datasets of lncRNAs, miRNAs, and mRNAs in CCA as well as relevant clinical information were obtained from the Cancer Genome Atlas (TCGA) database. After pretreatment, differentially expressed RNAs (DERNAs) were identified and further interrogated for their correlations with clinical information. Prognostic RNAs were selected using univariate Cox regression. Then, a ceRNA network was constructed based on these RNAs.

Results

We identified a total of five prognostic DEmiRNAs, 63 DElncRNAs, and 90 DEmRNAs between CCA and matched normal tissues. Integrating the relationship between the different types of RNAs, an lncRNA-miRNA-mRNA network was established and included 28 molecules and 47 interactions. Screened prognostic RNAs involved in the ceRNA network included 3 miRNAs (hsa-mir-1295b, hsa-mir-33b, and hsa-mir-6715a), 7 lncRNAs (ENSG00000271133, ENSG00000233834, ENSG00000276791, ENSG00000241155, COL18A1-AS1, ENSG00000274737, and ENSG00000235052), and 18 mRNAs (ANO9, FUT4, MLLT3, ABCA3, FSCN2, GRID2IP, NCK2, MACC1, SLC35E4, ST14, SH2D3A, MOB3B, ACTL10, RAB36, ATP1B3, MST1R, SEMA6A, and SEL1L3).

Conclusions

Our study identified novel prognostic makers and predicted a previously unknown ceRNA regulatory network in CCA and may provide novel insight into a further understanding of lncRNA-mediated ceRNA regulatory mechanisms in CCA.

Comprehensive analysis of potential prognostic genes for the construction of a competing endogenous RNA regulatory network in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is an extremely common malignant tumor with worldwide prevalence. The aim of this study was to identify potential prognostic genes and construct a competing endogenous RNA (ceRNA) regulatory network to explore the mechanisms underlying the development of HCC.

METHODS

Integrated analysis was used to identify potential prognostic genes in HCC with R software based on the GSE14520, GSE17548, GSE19665, GSE29721, GSE60502, and the Cancer Genome Atlas databases. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway-enrichment analyses were performed to explore the molecular mechanisms of potential prognostic genes. Differentially expressed miRNAs (DEMs) and lncRNAs (DELs) were screened based on the Cancer Genome Atlas database. An lncRNA-miRNA-mRNA ceRNA regulatory network was constructed based on information about interactions derived from the miRcode, TargetScan, miRTarBase, and miRDB databases.

RESULTS

A total of 152 potential prognostic genes were screened that were differentially expressed in HCC tissue and significantly associated with overall survival of HCC patients. There were 13 key potential prognostic genes in the ceRNA regulatory network: eleven upregulated genes (CCNB1, CEP55, CHEK1, EZH2, KPNA2, LRRC1, PBK, RRM2, SLC7A11, SUCO, and ZWINT) and two downregulated genes (ACSL1 and CDC37L1) whose expression might be regulated by eight DEMs and 61 DELs. Kaplan-Meier curve analysis showed that nine DELs (AL163952.1, AL359878.1, AP002478.1, C2orf48, C10orf91, CLLU1, CLRN1-AS1, ERVMER61-1, and WARS2-IT1) in the ceRNA regulatory network were significantly associated with HCC-patient prognoses.

CONCLUSION

This study identified potential prognostic genes and constructed an lncRNA- miRNA-mRNA ceRNA regulatory network of HCC, which not only has important clinical significance for early diagnoses but also provides effective targets for HCC treatments and could provide new insights for HCC-interventional strategies.

The Advancement of Long Non-Coding RNAs in Cholangiocarcinoma Development

Cholangiocarcinoma (CCA) is a malignancy with increasing incidence in recent years. CCA patients are usually diagnosed at advanced stage due to lack of apparent symptoms and specifically diagnostic markers. Nowadays, surgical removal is the only effective method for CCA whereas overall 5-year-survival rate keeps around 10%. Long-noncoding RNA (lncRNA), a subtype of noncoding RNA, is widely studied to be abnormally expressed in multiple cancers including CCA. LncRNA can promote proliferation, migration, invasion and inhibit apoptosis of CCA. Moreover, lncRNA is negatively correlated with the prognosis of CCA. LncRNA may contribute to the development of CCA via modulating gene transcription, sponging microRNA, regulating CCA-related signaling pathways or protein expression. LncRNA is thought to be potential diagnostic markers and therapeutic targets for CCA.