Methylation and Noncoding RNAs in Gastric Cancer: Everything Is Connected.

Despite recent progress, gastric cancer remains one of the most common cancers and has a high mortality rate worldwide. Aberrant DNA methylation pattern and deregulation of noncoding RNA expression appear in the early stages of gastric cancer. Numerous investigations have confirmed their significant role in gastric cancer tumorigenesis and their high potential as diagnostic and prognostic biomarkers. Currently, it is clear that these epigenetic regulators do not work alone but interact with each other, generating a complex network. The aim of our review was to summarize the current knowledge of this interaction in gastric cancer and estimate its clinical potential for the diagnosis, prognosis, and treatment of the disease.

Nucleolar RNA polymerase II drives ribosome biogenesis.

Proteins are manufactured by ribosomes-macromolecular complexes of protein and RNA molecules that are assembled within major nuclear compartments called nucleoli1,2. Existing models suggest that RNA polymerases I and III (Pol I and Pol III) are the only enzymes that directly mediate the expression of the ribosomal RNA (rRNA) components of ribosomes. Here we show, however, that RNA polymerase II (Pol II) inside human nucleoli operates near genes encoding rRNAs to drive their expression. Pol II, assisted by the neurodegeneration-associated enzyme senataxin, generates a shield comprising triplex nucleic acid structures known as R-loops at intergenic spacers flanking nucleolar rRNA genes. The shield prevents Pol I from producing sense intergenic noncoding RNAs (sincRNAs) that can disrupt nucleolar organization and rRNA expression. These disruptive sincRNAs can be unleashed by Pol II inhibition, senataxin loss, Ewing sarcoma or locus-associated R-loop repression through an experimental system involving the proteins RNaseH1, eGFP and dCas9 (which we refer to as 'red laser'). We reveal a nucleolar Pol-II-dependent mechanism that drives ribosome biogenesis, identify disease-associated disruption of nucleoli by noncoding RNAs, and establish locus-targeted R-loop modulation. Our findings revise theories of labour division between the major RNA polymerases, and identify nucleolar Pol II as a major factor in protein synthesis and nuclear organization, with potential implications for health and disease.

Linc01555 promotes proliferation, migration and invasion of gastric carcinoma cells by interacting with Notch signaling pathway.

PURPOSE: To detect the expression level of long non-coding ribonucleic acid 01555 (linc01555) in gastric cancer (GC) tissues and cells, and its effects on the biological functions of GC cells. METHODS: The relative expression of linc01555 in 61 cases of GC and para-carcinoma tissues and GC cells was detected via quantitative reverse transcription-polymerase chain reaction (qRT-PCR). GC cells were divided into experimental group (si-linc01555) and control group (si-NC), and the interference efficiency was detected through qRT-PCR. The effects of interference in linc01555 expression on GC cell proliferation, colony formation ability, migration and invasion were determined using cell counting kit-8 (CCK-8) assay, colony formation assay, wound healing assay and Transwell assay. Moreover, the expressions of molecular markers in the downstream Notch pathway were detected using western blotting. RESULTS: The results of qRT-PCR showed that the expression of linc01555 was upregulated in GC tissues and cells. The results of CCK-8 assay revealed that the proliferative activity of GC cells declined after interference in linc01555 expression. It was found in colony formation assay that the proliferation ability of GC cells declined after interference in linc01555 expression, and it was observed in wound healing assay that the cell migration ability in the experimental group was weakened compared with that in the control group. According to the results of transwell assay, both migration and invasion ability of GC cells declined after interference in linc01555 expression. Finally, the western blotting showed that there were changes in the expressions of molecular markers in the Notch signaling pathway after interference in linc01555 expression. CONCLUSIONS: The expression of linc01555 is upregulated in GC tissues and cells, and the highly-expressed linc01555 promotes the proliferation, invasion and metastasis of GC cells through the Notch signaling pathway.

PART1 and hsa-miR-429-Mediated SHCBP1 Expression Is an Independent Predictor of Poor Prognosis in Glioma Patients.

Gliomas are the most common primary brain tumors. Because of their high degree of malignancy, patient survival rates are unsatisfactory. Therefore, exploring glioma biomarkers will play a key role in early diagnosis, guiding treatment, and monitoring the prognosis of gliomas. We found two lncRNAs, six miRNAs, and nine mRNAs that were differentially expressed by analyzing genomic data of glioma patients. The diagnostic value of mRNA expression levels in gliomas was determined by receiver operating characteristic (ROC) curve analysis. Among the nine mRNAs, the area under the ROC curve values of only CEP55 and SHCBP1 were >0.7, specifically 0.834 and 0.816, respectively. Additionally, CEP55 and SHCBP1 were highly expressed in glioma specimens and showed increased expression according to the glioma grade, and outcomes of high expression patients were poor. CEP55 was enriched in the cell cycle, DNA replication, mismatch repair, and P53 signaling pathway. SHCBP1 was enriched in the cell cycle, DNA replication, ECM receptor interaction, and P53 signaling pathway. Age, grade, IDH status, chromosome 19/20 cogain, and SHCBP1 were independent factors for prognosis. Our findings suggest the PART1-hsa-miR-429-SHCBP1 regulatory network plays an important role in gliomas.

Long intergenic noncoding RNA profiles of pheochromocytoma and paraganglioma: A novel prognostic biomarker.

Many long intergenic noncoding RNAs (lincRNAs) serve as cancer biomarkers for diagnosis or prognostication. To understand the role of lincRNAs in the rare neuroendocrine tumors pheochromocytoma and paraganglioma (PCPG), we performed first time in-depth characterization of lincRNA expression profiles and correlated findings to clinical outcomes of the disease. RNA-Seq data from patients with PCPGs and 17 other tumor types from The Cancer Genome Atlas and other published sources were obtained. Differential expression analysis and a machine-learning model were used to identify transcripts specific to PCPGs, as well as established PCPG molecular subtypes. Similarly, lincRNAs specific to aggressive PCPGs were identified, and univariate and multivariate analysis was performed for metastasis-free survival. The results were validated in independent samples using RT-PCR. From a pan-cancer context, PCPGs had a specific and unique lincRNA profile. Among PCPGs, five different molecular subtypes were identified corresponding to the established molecular classification. Upregulation of 13 lincRNAs was found to be associated with aggressive/metastatic PCPGs. RT-PCR validation confirmed the overexpression of four lincRNAs in metastatic compared to non-metastatic PCPGs. Kaplan-Meier analysis identified five lincRNAs as prognostic markers for metastasis-free survival of patients in three subtypes of PCPGs. Stratification of PCPG patients with a risk-score formulated using multivariate analysis of lincRNA expression profiles, presence of key driver mutations, tumor location, and hormone secretion profiles showed significant differences in metastasis-free survival. PCPGs thus exhibit a specific lincRNA expression profile that also corresponds to the established molecular subgroups and can be potential marker for the aggressive/metastatic PCPGs.

LncRNA PTCSC3 inhibits the proliferation, invasion and migration of cervical cancer cells via sponging miR-574-5p.

Dysregulation of long non-coding RNA papillary thyroid carcinoma susceptibility candidate 3 (lncRNA PTCSC3) has been found to correlate with various types of cancers. Quantitative RT-PCR showed a down-regulation of PTCSC3 in cervical cancer tissues compared with normal cervical tissues. The present study aimed to investigate the role of lncRNA PTCSC3 in cervical cancer and the underlying mechanisms. PTCSC3 was overexpressed in cervical cancer cell lines C-33A and Hela by transfection with pcDNA3.1-lncRNA PTCSC3 expressing plasmid. Overexpression of lncRNA PTCSC3 inhibited cell proliferation, induced cell cycle arrest, and suppressed cell invasion and migration using CCK8 assay, flow cytometry, Transwell assay and wound healing examination, respectively. Western blotting analysis showed that PTCSC3 overexpression decreased the expression of cyclinD1, matrix metalloproteinases 9 (MMP9), N-cadherin and ß-catenin and increased E-cadherin expression. Further, PTCSC3 negatively regulated miR-574-5p expression and dual-luciferase assay verified the binding activity between miR-574-5p and lncRNA PTCSC3. Enforced up-regulation of miR-574-5p abolished the inhibitory effect of lncRNA PTCSC3 on cervical cancer cell proliferation, invasiveness and mobility. Taken together, lncRNA PTCSC3 inhibited cell growth and metastasis via sponging miR-574-5p in cervical cancer. Therefore, we demonstrate the tumour-suppressive function of lncRNA PTCSC3 in cervical cancer and suggest that PTCSC3 is a potential therapeutic target for cervical cancer.

The Roles of Hypoxia-Inducible Factors and Non-Coding RNAs in Gastrointestinal Cancer.

Hypoxia-inducible factors (HIFs) are transcription factors that play central roles in cellular responses against hypoxia. In most cancers, HIFs are closely associated with tumorigenesis by regulating cell survival, angiogenesis, metastasis, and adaptation to the hypoxic tumor microenvironment. Recently, non-coding RNAs (ncRNAs) have been reported to play critical roles in the hypoxic response in various cancers. Here, we review the roles of hypoxia-response ncRNAs in gastrointestinal cancer, with a particular focus on microRNAs and long ncRNAs, and discuss the functional relationships and regulatory mechanisms between HIFs and ncRNAs.

Multidimensional analysis of Gammaherpesvirus RNA expression reveals unexpected heterogeneity of gene expression.

Virus-host interactions are frequently studied in bulk cell populations, obscuring cell-to-cell variation. Here we investigate endogenous herpesvirus gene expression at the single-cell level, combining a sensitive and robust fluorescent in situ hybridization platform with multiparameter flow cytometry, to study the expression of gammaherpesvirus non-coding RNAs (ncRNAs) during lytic replication, latent infection and reactivation in vitro. This method allowed robust detection of viral ncRNAs of murine gammaherpesvirus 68 (γHV68), Kaposi's sarcoma associated herpesvirus and Epstein-Barr virus, revealing variable expression at the single-cell level. By quantifying the inter-relationship of viral ncRNA, viral mRNA, viral protein and host mRNA regulation during γHV68 infection, we find heterogeneous and asynchronous gene expression during latency and reactivation, with reactivation from latency identified by a distinct gene expression profile within rare cells. Further, during lytic replication with γHV68, we find many cells have limited viral gene expression, with only a fraction of cells showing robust gene expression, dynamic RNA localization, and progressive infection. Lytic viral gene expression was enhanced in primary fibroblasts and by conditions associated with enhanced viral replication, with multiple subpopulations of cells present in even highly permissive infection conditions. These findings, powered by single-cell analysis integrated with automated clustering algorithms, suggest inefficient or abortive γHV infection in many cells, and identify substantial heterogeneity in viral gene expression at the single-cell level.

[Differences in circRNA expression profiles between HER-2-positive breast cancer cells and normal mammary epithelial cells].

Objective: To investigate the differential expression profiles of circular RNA (circRNA) in human epidermal growth factor receptor 2 (HER-2) positive breast cancer cells and normal mammary epithelial cells, and to develop novel diagnostic and therapeutic markers for HER-2 positive breast cancer. Methods: Total RNA were extracted from HER-2 positive breast cancer cell SK-BR-3 and normal mammary epithelial cell MCF10A. RNA quality was detected using NanoDrop ND-1000. Rnase R was applied to remove linear RNA and enrich circRNAs. After amplification and reverse transcription into fluorescent complementary RNA (cRNA) using random primer, the labeled cRNAs were hybridized onto the Arraystar Human circRNA Arrays. The raw data were extracted and the acquired array images were subjected to quantile normalization followed by heat map and volcano plot analysis. The expression of circRNAs with large fold change was verified by real-time quantitative polymerase chain reaction (RT-qPCR). Finally, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed in the differentially expressed circRNAs and circRNA-microRNA (miRNA) network was constructed. Results: The total RNA extracted from SK-BR-3 and MCF10A had high integrity and quality. The expression profiles of circRNA in SK-BR-3 and MCF10A cells were significantly different shown by fluorescent expression signals. Compared with MCF10A cells, there were 6 584 up-regulated circRNAs and 6254 down-regulated circRNAs in SK-BR-3 cells. There were 348 circRNAs with |log(2)FC|≥2, of which 153 were up-regulated and 195 were down-regulated. Moreover, 8 circRNAs with |log(2)FC|>5. Among them, 5 were up-regulated in SK-BR-3 cells, including hsa_circRNA_074595 (|log(2)FC|=7.84), hsa_circRNA_074598 (|log(2)FC|=6.50), hsa_circRNA_085362 (|log(2)FC|=5.86), hsa_circRNA_101379 (|log(2)FC|=5.71) and hsa_circRNA_406683 (|log(2)FC|=5.34); as well as 3 were down-regulated, including hsa_circRNA_021714 (|log(2)FC|=5.46), hsa_circRNA_100777 (|log(2)FC|=5.40), and hsa_circRNA_100796 (|log(2)FC|=5.03). The expression levels of hsa_circRNA_074595, hsa_circRNA_074598 and hsa_circRNA_100777 were further validated by RT-qPCR in consistent with the results of microarray. GO analysis showed that differentially expressed circRNAs were significantly enriched in the biological process of heart development (P<0.001), cellular component in the cell adhesion-related components (P<0.001), molecular function in protein serine/threonine kinase activity (P<0.001). KEGG analysis revealed that differentially expressed circRNAs were significantly enriched in the PI3K-Akt signaling pathway. Conclusions: The expression profile of circRNA in HER-2 positive breast cancer cells is significantly different from that in normal mammary epithelial cells. The differentially expressed circRNAs may be served as potential diagnostic or therapeutic targets for HER-2 positive breast cancer.

Integrated analysis of a competing endogenous RNA network reveals key long noncoding RNAs as potential prognostic biomarkers for hepatocellular carcinoma.

Growing evidence has revealed that long noncoding RNAs (lncRNAs) have an important impact on tumorigenesis and tumor progression via a mechanism involving competing endogenous RNAs (ceRNAs). However, their use in predicting the survival of a patient with hepatocellular carcinoma (HCC) remains unclear. The aim of this study was to develop a novel lncRNA expression-based risk score system to accurately predict the survival of patients with HCC. In our study, using expression profiles downloaded from The Cancer Genome Atlas database, the differentially expressed messenger RNAs (mRNAs), lncRNAs, and microRNAs (miRNAs) were explored in patients with HCC and normal liver tissues, and then a ceRNA network constructed. A risk score system was established between lncRNA expression of the ceRNA network and overall survival (OS) or recurrence-free survival (RFS); it was further analyzed for associations with the clinical features of patients with HCC. In HCC, 473 differentially expressed lncRNAs, 63 differentially expressed miRNAs, and 1417 differentially expressed mRNAs were detected. The ceRNA network comprised 41 lncRNA nodes, 12 miRNA nodes, 24 mRNA nodes, and 172 edges. The lncRNA expression-based risk score system for OS was constructed based on six lncRNAs (MYLK-AS1, AL359878.1, PART1, TSPEAR-AS1, C10orf91, and LINC00501), while the risk score system for RFS was based on four lncRNAs (WARS2-IT1, AL359878.1, AL357060.1, and PART1). Univariate and multivariate Cox analyses showed the risk score systems for OS or RFS were significant independent factors adjusted for clinical factors. Receiver operating characteristic curve analysis showed the area under the curve for the risk score system was 0.704 for OS, and 0.71 for RFS. Our result revealed a lncRNA expression-based risk score system for OS or RFS can effectively predict the survival of patients with HCC and aid in good clinical decision-making.

Exosome-mediated transfer of lncRNA PART1 induces gefitinib resistance in esophageal squamous cell carcinoma via functioning as a competing endogenous RNA.

BACKGROUND: Currently, resistance to tyrosine kinase inhibitors, such as gefitinib, has become a major obstacle in improving the clinical outcome of patients with metastatic and advanced-stage esophageal squamous cell carcinoma (ESCC). While cell behavior can be modulated by long non-coding RNAs (lncRNAs), the roles of lncRNAs within extracellular vesicles (exosomes) are largely unknown. Therefore, we investigated the involvement and regulatory functions of potential lncRNAs enclosed in exosomes during formation of chemoresistance in human ESCC. METHODS: Gefitinib-resistant cell lines were established by continuously grafting TE1 and KYSE-450 cells into gefitinib-containing culture medium. LncRNA microarray assay followed by RT-qPCR were used to verify the differential expression of lncRNA Prostate Androgen-Regulated Transcript 1 (PART1) between gefitinib resistant and parental cell lines. RNA fluorescence in situ hybridization (FISH) was used to investigate whether extracellular PART1 could be incorporated into exosomes and transmitted to recipient cells. Subsequently, a series of in vitro assays and a xenograft tumor model were used to observe the functions of lncRNA PART1 in ESCC cells. A signal transduction reporter array, bioinformatics analysis, western blotting, and immunofluorescence were carried out to verify the regulation of PART1 and its downstream Bcl-2 signaling pathway. RESULTS: lncRNA PART1 was upregulated in gefitinib-resistant cells when compared to parental ESCC cells. It was found that STAT1 can bind to the promoter region of lncRNA PART1, resulting in its activation. Knockdown of lncRNA PART1 potently promoted the gefitinib-induced cell death, while elevated PART1 promoted gefitinib resistance by competitively binding to miR-129 to facilitate Bcl-2 expression in ESCC cells. In addition, extracellular PART1 could be incorporated into exosomes and transmitted to sensitive cells, thus disseminating gefitinib resistance. Clinically, high levels of serum lncRNA PART1 in exosome were associated with poor response to gefitinib treatment in ESCC patients. CONCLUSIONS: LncRNA PART1 promotes gefitinib resistance by regulating miR-129/Bcl-2 pathway, and may serve as a therapeutic target for ESCC patients.

Epigenome editing of microsatellite repeats defines tumor-specific enhancer functions and dependencies.

Various types of repetitive sequences are dysregulated in cancer. In Ewing sarcoma, the oncogenic fusion protein EWS-FLI1 induces chromatin features typical of active enhancers at GGAA microsatellite repeats, but the function of these sites has not been directly demonstrated. Here, by combining nascent transcription profiling with epigenome editing, we found that a subset of GGAA microsatellite repeats is transcriptionally active in Ewing sarcoma and that silencing individual repeats abolishes local nascent transcription and leads to markedly reduced expression of putative target genes. Epigenome silencing of these repeat sites does not affect gene expression in unrelated cells, can prevent the induction of gene expression by EWS-FLI1, and, in the case of a GGAA repeat that controls SOX2 expression from a distance of 470 kb, is sufficient to impair the growth of Ewing sarcoma xenografts. Using an experimental approach that is broadly applicable to testing different types of repetitive genomic elements, our study directly demonstrates that specific repeat microsatellites can have critical gene regulation functions in cancer and thus represent tumor-specific vulnerabilities that may be exploited to develop new therapies.

Identification of a noncoding RNA­mediated gene pair­based regulatory module in Alzheimer's disease.

Alzheimer's disease (AD) is the most common type of neurological disorder that results from brain cell death; however, not all brain regions are simultaneously affected to the same extent. Despite single biomarkers for AD having been determined on a genome­wide scale, the differential co­expression in gene pairs between regions and interactions with other types of cellular molecules, particularly non­coding (nc)RNAs, are often overlooked in studies investigating the underlying mechanisms associated with AD. In the present study, based on 1,548 samples obtained from a cohort of 90 patients with AD spanning 19 brain regions, a gene­pair based method was established for the classification of 19 brain regions into seven different groups, including marked disparate groupings of six single regions and a cluster of another 13 regions as revealed by principal component analysis (PCA). To further investigate the different underlying mechanisms associated with each group, five highly interconnected functional modules of the protein­protein interaction network were demonstrated to characterize the seven region groups containing six single groups and 13 clustered regions based on 4,731 gene­pairs. Genes in two of the functional modules exhibited a strong association with pathways associated with the nervous system, including cholinergic synapses, circadian entrainment and dopaminergic synapses. Notably, following integration of these two modules with a ncRNA­mediated network, one module demonstrated a strong association with micro (mi)RNAs, which were revealed to interact with numerous long non­coding (lnc)RNAs associated with AD, such as metastasis associated lung adenocarcinoma transcript 1 and taurine upregulated 1. This suggested that mRNAs and lncRNAs may represent competing endogenous RNAs for binding with miRNAs. Thus, these results indicated that the ncRNA­mediated gene regulatory module detected by the established gene pair­based method may further the understanding of underlying mechanisms associated with AD as well as aid the development of novel therapeutic strategies for the treatment of patients with AD.

Competing endogenous RNA network crosstalk reveals novel molecular markers in colorectal cancer.

The competing endogenous RNA networks play a pivotal role in cancer diagnosis and progression. Novel properstrategies for early detection of colorectal cancer (CRC) are strongly needed. We investigated a novel CRC-specific RNA-based integrated competing endogenous network composed of lethal3 malignant brain tumor like1 (L3MBTL1) gene, long non-coding intergenic RNA- (lncRNA RP11-909B2.1) and homo sapiens microRNA-595 (hsa-miRNA-595) using in silico data analysis. RT-qPCR-based validation of the network was achieved in serum of 70 patients with CRC, 40 patients with benign colorectal neoplasm, and 20 healthy controls. Moreover, in cancer tissues of 20 of the 70 CRC cases were involved in the study. The expression of RNA-based biomarker network in both CRC and adjacent non-tumor tissues and their correlation with the serum levels of this network members was investigated. Lastly, the expression levels of the chosen ceRNA was verified in CRC cell line. Our results revealed that the three RNAs-based biomarker network (long non-coding intergenic RNA-[lncRNA RP11-909B2.1], Homo sapiens microRNA-595 [hsa-miRNA-595], and L3MBTL1 mRNA), had high sensitivity and specificity for discriminating CRC from healthy controls and also from benign colorectal neoplasm. The data suggest that among these three RNAs, serum lncRNA RP11-909B2.1 could be a promising independent prognostic factors in CRC. The circulatory RNA based biomarker panel can act as potential biomarker for CRC diagnosis and prognosis.

CircRNA_0023642 promotes migration and invasion of gastric cancer cells by regulating EMT.

OBJECTIVE: Non-coding circular RNAs (circRNAs) have displayed dysregulated expression in various tumor tissues. However, their role in the progression of cancers remains largely unknown. We aimed at examining the expression, functions, and molecular mechanisms of a new circRNA (circRNA_0023642) in gastric cancer (GC). PATIENTS AND METHODS: We evaluated the expression levels of circRNA_0023642 in GC tissues, adjacent normal tissues and cells lines using qRT-PCR. The functional roles of circRNA_0023642 in GC were determined by Cell Counting Kit-8 (CCK-8) assay, colony formation assay, transwell assay, and flow cytometric analysis. Western blot was used to analyze the effect of circRNA_0023642 on the expression of EMT-related proteins. RESULTS: We found that circRNA_0023642 was upregulated in GC tissues and cell lines. Functionally, down-regulation of circRNA_0023642 displayed the tumor-inhibitory effects by suppressing cell proliferation, migration, and invasion as well as inducing apoptosis. Mechanically, our results revealed that the abnormal expression of circRNA_0023642 could influence the EMT signaling pathway, which was demonstrated by measuring the expression levels of N-cadherin, vimentin snail, and E-cadherin. CONCLUSIONS: Our findings suggest that circRNA_0023642 serves as a metastasis activator by promoting EMT and may represent a novel molecular therapeutic target for GC.

Central role of the p53 pathway in the noncoding-RNA response to oxidative stress.

Oxidative stress plays a fundamental role in many conditions. Specifically, redox imbalance inhibits endothelial cell (EC) growth, inducing cell death and senescence. We used global transcriptome profiling to investigate the involvement of noncoding-RNAs in these phenotypes. By RNA-sequencing, transcriptome changes were analyzed in human ECs exposed to H2O2, highlighting a pivotal role of p53-signaling. Bioinformatic analysis and validation in p53-silenced ECs, identified several p53-targets among both mRNAs and long noncoding-RNAs (lncRNAs), including MALAT1 and NEAT1. Among microRNAs (miRNAs), miR-192-5p was the most induced by H2O2 treatment, in a p53-dependent manner. Down-modulated mRNA-targets of miR-192-5p were involved in cell cycle, DNA repair and stress response. Accordingly, miR-192-5p overexpression significantly decreased EC proliferation, inducing cell death. A central role of the p53-pathway was also confirmed by the analysis of differential exon usage: Upon H2O2 treatment, the expression of p53-dependent 5'-isoforms of MDM2 and PVT1 increased selectively. The transcriptomic alterations identified in H2O2-treated ECs were also observed in other physiological and pathological conditions where redox control plays a fundamental role, such as ECs undergoing replicative senescence, skeletal muscles of critical limb-ischemia patients and the peripheral-blood mononuclear cells of long-living individuals. Collectively, these findings indicate a prominent role of noncoding-RNAs in oxidative stress response.

Long non-coding RNA CASC15 is upregulated in hepatocellular carcinoma and facilitates hepatocarcinogenesis.

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, accounting for one-sixth of all malignant tumors, and the mortality rate of HCC ranks second among all cancer-related deaths. Increasing evidence has recently shown that long non-coding RNAs (lncRNAs) play an important role in cancer occurrence and progression, including HCC. Cancer susceptibility candidate 15 (CASC15), a lncRNA, has been reported to be involved in melanoma progression and phenotype switching. However, the function of CASC15 in human HCC is still unknown. In the present study, we evaluated expression of CASC15 and its potential functions in HCC. The expression of CASC15 in HCC tissues was quantitated by the reverse-transcription quantitative polymerase chain reaction, which showed that CASC15 was overexpressed in 59% (48/82) of HCC tissues compared with corresponding adjacent normal tissues, and the CASC15 expression level was significantly correlated with metastasis (P=0.012), tumor size (P=0.037), and TNM stage (P=0.013). Kaplan-Meier survival curves showed that high CASC15 expression was associated with poor prognosis in HCC patients (P<0.05). Moreover, a knockdown model of CASC15 was established, which showed that CASC15 significantly impaired HCC cell proliferation, migration, and invasion. CASC15 knockdown also induced cell apoptosis in vitro and impaired tumor growth in vivo. In conclusion, CASC15 plays an important role in the progression of HCC, acting as an oncogene. High expression of CASC15 is correlated with a poor prognosis, suggesting that CASC15 may be a predictive biomarker of HCC.

Phosphorylated Mechanistic Target of Rapamycin (p-mTOR) and Noncoding RNA Expression in Follicular and Hürthle Cell Thyroid Neoplasm.

Oncocytic (Hürthle cell) and follicular neoplasms are related thyroid tumors with distinct molecular profiles. Diagnostic criteria separating adenomas and carcinomas for these two types of neoplasms are similar, but there may be some differences in the biological behavior of Hürthle cell and follicular carcinomas. Recent studies have shown that noncoding RNAs may have diagnostic and prognostic utility in separating benign and malignant Hürthle cell and follicular neoplasms. In this study, we examined expression of various noncoding RNAs including metastasis associated lung adenocarcinoma transcript 1 (MALAT1) and miR-RNA-885-5p (miR-885) in distinguishing between benign and malignant neoplasms. In addition, the expression of phosphorylated mechanistic receptor of rapamycin (p-mTOR) was also analyzed in these two groups of tumors. Tissue microarrays (TMAs) with archived tissue samples were analyzed using in situ hybridization (ISH) for MALAT1 and miR-885 and immunohistochemistry (IHC) for p-mTOR. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was also performed on a subset of the cases.MALAT1 and miR-885 were increased in all neoplastic groups compared to the normal thyroid tissues (p < 0.05). MALAT1 was more highly expressed in HCCs compared to FTCs, although the differences were not statistically significant (p = 0.06). MiR-885 was expressed at similar levels in FTCs and HCCs. P-mTOR protein was more highly expressed in FTCs than in HCCs (p<0.001). qRT-PCR analysis of noncoding RNAs supported the ISH findings. These results indicate that the noncoding RNAs MALAT1 and miR-885 show increased expression in neoplastic follicular and Hürthle cell thyroid neoplasms compared to normal thyroid tissues. P-mTOR was most highly expressed in FTC but was also increased in HCC, suggesting that drugs targeting this pathway may be useful for treatment of tumors unresponsive to conventional therapies.

New Insights into the Epigenetics of Hepatocellular Carcinoma.

Hepatocellular Carcinoma (HCC) is one of the most predominant malignancies with high fatality rate. This deadly cancer is rising at an alarming rate because it is quite resistant to radio- and chemotherapy. Different epigenetic mechanisms such as histone modifications, DNA methylation, chromatin remodeling, and expression of noncoding RNAs drive the cell proliferation, invasion, metastasis, initiation, progression, and development of HCC. These epigenetic alterations because of potential reversibility open way towards the development of biomarkers and therapeutics. The contribution of these epigenetic changes to HCC development has not been thoroughly explored yet. Further research on HCC epigenetics is necessary to better understand novel molecular-targeted HCC treatment and prevention. This review highlights latest research progress and current updates regarding epigenetics of HCC, biomarker discovery, and future preventive and therapeutic strategies to combat the increasing risk of HCC.

Long noncoding RNA papillary thyroid carcinoma susceptibility candidate 3 (PTCSC3) inhibits proliferation and invasion of glioma cells by suppressing the Wnt/ß-catenin signaling pathway.

BACKGROUND: The dysregulation of long noncoding RNAs (lncRNAs) has been identified in a variety of cancers. An increasing number of studies have found the critical role of lncRNAs in the regulation of cellular processes, such as proliferation, invasion and differentiation. Long noncoding RNA papillary thyroid carcinoma susceptibility candidate 3 (PTCSC3) is a novel lncRNA that was primarily detected in papillary thyroid carcinoma. However, the biological function and molecular mechanism of lncRNA PTCSC3 in glioma are still unknown. METHODS: The expression level of lncRNA PTCSC3 in human microglia and glioma cell lines was examined using quantitative real-time polymerase chain reaction (qRT-PCR). The influence of lncRNA PTCSC3 on cell proliferation were studied using the cell counting kit-8, and cell cycle and apoptosis were analyzed by flow cytometry assays. The migration and invasion abilities were investigated by transwell and wound healing assays. The target genes of lncRNA PTCSC3 were explored by qRT-PCR, immunofluorescence and western blot. RESULTS: LncRNA PTCSC3 was significantly downregulated in glioma cell lines. The overexpression of lncRNA PTCSC3 suppressed proliferation and induced apoptosis in U87 and U251 cells. Additionally, the overexpression of lncRNA PTCSC3 inhibited the migration and invasion of U87 and U251 cells. Moreover, lncRNA PTCSC3 inhibited the epithelial-mesenchymal transition of U87 cells. The study also demonstrated that LRP6, as a receptor of the Wnt/ß-catenin pathway, was a target of lncRNA PTCSC3. By evaluating the expression levels of Axin1, active ß-catenin, c-myc, and cyclin D1, the study indicated that lncRNA PTCSC3 inhibited the activation of the Wnt/ß-cateninpathway through targeting LRP6. CONCLUSIONS: LncRNA PTCSC3 inhibits the proliferation and migration of glioma cells and suppresses Wnt/ß-catenin signaling pathway by targeting LRP6. LncRNA PTCSC3 is a potential therapeutic target for treatment of glioma.