Prognostic role of lncRNA HOTAIR in esophageal squamous cell carcinoma

Non‑coding RNA: A promising diagnostic biomarker and therapeutic target for esophageal squamous cell carcinoma (Review)

Esophageal cancer (EC) is a common form of malignant tumor in the digestive system that is classified into two types: Esophageal squamous cell carcinomas (ESCC) and esophageal adenocarcinoma. ESCC is known for its early onset of symptoms, which can be difficult to identify, as well as its rapid progression and tendency to develop drug resistance to chemotherapy and radiotherapy. These factors contribute to the high incidence of disease and low cure rate. Therefore, a diagnostic biomarker and therapeutic target need to be identified for ESCC. Non-coding RNAs (ncRNAs) are a class of molecules that are transcribed from DNA but do not encode proteins. Initially, ncRNAs were considered to be non-functional segments generated during transcription. However, with advancements in high-throughput sequencing technologies in recent years, ncRNAs have been associated with poor prognosis, drug resistance and progression of ESCC. The present study provides a comprehensive overview of the biogenesis, characteristics and functions of ncRNAs, particularly focusing on microRNA, long ncRNAs and circular RNAs. Furthermore, the ncRNAs that could potentially be used as diagnostic biomarkers and therapeutic targets for ESCC are summarized to highlight their application value and prospects in ESCC.

Non-coding RNAs and gastrointestinal cancers prognosis: an umbrella review of systematic reviews and meta-analyses of observational studies

Aim

Provide an overview and a systematic evaluation of the evidence quality on the association between non-coding RNAs (ncRNAs) and prognosis value for gastrointestinal cancers (GICs).

Methods

We searched the literature from three electronic databases: Pubmed, Embase, and Web of science, then carefully screened and extracted the primary information and results from the included articles. We use A measurable systematic review and meta-analysis evaluation tool (AMSTAR2) to evaluate the quality of methodology and then use the Grading of Recommendations Assessment 2, Development and Evaluation guideline (GRADE) make sure the reliability of the meta-analysis.

Results

Overall, 182 meta-analyses from 58 studies were included in this study. Most of these studies are of low or very low quality. Using the scoring tool, we found that only two meta-analyses were rated as high reliability, and 17 meta-analyses were rated as medium reliability.

Conclusions

Although ncRNA has good prognostic value in some studies, only a tiny amount of evidence is highly credible at present. More research is needed in the future.

PROSPERO registration number

CRD42022382296.

Status of diagnosis and treatment of esophageal cancer and non-coding RNA correlation research: a narrative review

OBJECTIVE

To describe and discuss the progression of the non-coding RNA as biomarkers in early esophageal cancer.

BACKGROUND

Esophageal cancer without obvious symptoms during early stages is one of the most common cancers, the current clinical treatments offer possibilities of a cure, but the survival rates and the prognoses remain poor, it is a serious threat to human life and health. Most patients are usually diagnosed during terminal stages due to low sensitivity of esophageal cancer's early detection techniques. With the development of molecular biology, an increasing number of non-coding RNAs are found to be associated with the occurrence, development, and prognosis of esophageal cancer. Some of these have begun to be used in clinics and laboratories for diagnosis, treatment, and prognosis, with the goal of reducing mortality.

METHODS

The information for this paper was collected from a variety of sources, including a search of the keynote's references, a search for texts in college libraries, and discussions with experts in the field of esophageal cancer clinical treatment.

CONCLUSIONS

Non-coding RNA does play a regulatory role in the development of esophageal cancer, which can predict the occurrence or prognosis of tumors, and become a new class of tumor markers and therapeutic targets in clinical applications. In this review, we survey the recent developments in the incidence, diagnosis, and treatment of esophageal cancer, especially with new research progresses on non-coding RNA biomarkers in detail, and discuss its potential clinical applications.

Long Non-Coding RNA KCNQ1OT1 Promotes Progression of Hepatocellular Carcinoma by miR-148a-3p/IGF1R Axis

Accumulating evidence have suggested that long non-coding RNAs (lncRNAs) act as a critical regulator in tumorgenesis. LncRNA KCNQ1OT1 (KCNQ1OT1) has been recently shown to be dysregulated in many cancers. This study was aimed to explore the biological role of KCNQ1OT1 in hepatocellular carcinoma (HCC). In our study, we first observed the expression level of KCNQ1OT1 was distinctly up-regulated in HCC tissues and cell lines compared with adjacent non-cancer tissues and normal liver cell line. And clinical results indicated that higher expression of KCNQ1OT1 was correlated with poor prognosis of patients with HCC. Next, functional studies revealed that knockdown of KCNQ1OT1 induced apoptosis and repressed proliferation, migration and invasion of HCC cells. In addition, knockdown of KCNQ1OT1 suppressed xenograft tumor growth in vivo. Mechanically, we found that KCNQ1OT1 can promote the expression of IGF1R by functioning as a competing endogenous RNA of miR-148a-3p. In conclusion, our results shown the oncogenic role of KCNQ1OT1 in HCC by regulating the miR-148a-3p/IGF1R axis and may provide a new insight and a potential therapeutic target for HCC.

Long non-coding RNA XIST promotes the progression of esophageal squamous cell carcinoma through sponging miR-129-5p and upregulating CCND1 expression

Long non-coding RNA (lncRNA) X inactive specific transcript (XIST) has been identified as an oncogenic lncRNA in a series of human cancers, including esophageal squamous cell carcinoma (ESCC). In this study, we aimed to further explore the underlying mechanism of XIST on ESCC progression. qRT-PCR assay was used to determine the levels of XIST and miR-129-5p. Western blot analysis was performed to assess cyclin D1 (CCND1) expression. Bioinformatic analysis was performed using starBase v2.0 software. Dual-luciferase reporter and RNA immunoprecipitation assays were employed to confirm the interaction between XIST and miR-129-5p or miR-129-5p and CCND1. Cell cycle progression and apoptosis were measured by flow cytometric analysis, and cell migration and invasion were detected by transwell assay. Mouse studies were used to observe the effect of XIST silencing on tumor growth in vivo. Our results indicated that XIST was upregulated and miR-129-5p was downregulated in ESCC. XIST silencing or miR-129-5p overexpression repressed cell cycle progression, proliferation, migration, invasion, and promoted the apoptosis in ESCC cells. Moreover, XIST directly interacted with miR-129-5p and repressed miR-129-5p expression. MiR-129-5p mediated the regulatory effect of XIST on ESCC cell progression in vitro, and XIST promoted CCND1 expression by sponging miR-129-5p. Additionally, XIST silencing inhibited tumor growth in vivo. Our findings suggested that XIST silencing repressed the progression of ESCC at least partly through regulating the miR-129-5p/CCND1 axis. Targeting XIST might be a potential therapeutic strategy for ESCC treatment.

Clinicopathological Significance of Long Non-Coding RNA GHET1 in Human Cancers: A Meta-Analysis

Introduction:

Cancer is considered as the main public health problem and the second leading cause of morbidity and mortality worldwide. Numerous environmental-lifestyle related risk factors account for around one-third of cancer deaths. Recently, the key role of lncRNAs has been widely investigated in a variety of disorders, including cancer. The lncRNA GHET1 has been considered as an essential oncogenic lncRNA in many types of human cancers. Clinical investigations indicated that expression of lncRNA GHET1 is correlated with clinicopathological characteristics in cancer. This metaanalysis investigated the correlation between the lncRNA GHET1 expression and clinicopathological features in different types of cancers.

Materials and Methods:

Comprehensive literature searches in PubMed, Scopus, and Web of Knowledge were conducted up to April 11, 2019. Sixteen studies were included in this meta-analysis. All statistical analyses were conducted using Stata software, version 12.0.

Results:

The pooled OR and 95%CIs of the sixteen relevant studies showed that over expression of lncRNA GHET1 was associated with tumor-size ≥5 cm (OR= 2.51, 95% CI: 1.89-3.33, p=0.00, I2=38.30%), positive lymph node metastasis (OR= 2.83, 95% CI: 1.78-4.52, p=0.00, I2=45.60%), advanced tumor stage (OR= 3.92, 95% CI: 2.97-5.19, p=0.00, I2=0.00%), positive distant metastasis (OR= 5.74, 95% CI: 2.58-12.77, p=0.00, I2=0.00%), advanced tumor status (OR= 2.97, 95% CI: 1.40- 6.29, p=0.01, I2=34.70%), and positive vascular invasion (OR= 2.69, 95% CI: 1.61-4.50, p=0.00, I2=29.20%).

Conclusion:

Taken together, the current study demonstrated that overexpression of lncRNA GHET1 is significantly associated with clinicopathological features in human cancers. Our results suggested that lncRNA GHET1 can be utilized as a prognostic biomarker in human cancer.

Non-coding RNAs underlying chemoresistance in gastric cancer

BACKGROUND

Gastric cancer (GC) is a major health issue in the Western world. Current clinical imperatives for this disease include the identification of more effective biomarkers to detect GC at early stages and enhance the prevention and treatment of metastatic and chemoresistant GC. The advent of non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs) and long-non coding RNAs (lncRNAs), has led to a better understanding of the mechanisms by which GC cells acquire features of therapy resistance. ncRNAs play critical roles in normal physiology, but their dysregulation has been detected in a variety of cancers, including GC. A subset of ncRNAs is GC-specific, implying their potential application as biomarkers and/or therapeutic targets. Hence, evaluating the specific functions of ncRNAs will help to expand novel treatment options for GC.

CONCLUSIONS

In this review, we summarize some of the well-known ncRNAs that play a role in the development and progression of GC. We also review the application of such ncRNAs in clinical diagnostics and trials as potential biomarkers. Obviously, a deeper understanding of the biology and function of ncRNAs underlying chemoresistance can broaden horizons toward the development of personalized therapy against GC.

Long noncoding RNAs: Potential therapeutic targets in cardiocerebrovascular diseases

Cardiocerebrovascular disease is a collective term for cardiovascular and cerebrovascular diseases. Because of the complex mechanisms involved in cardiocerebrovascular diseases, limited effective treatments have been developed. With advancements in precision medicine, studies have focused on long noncoding RNAs (lncRNAs) in cerebrovascular diseases. LncRNAs, which are over 200 nucleotides long, regulate gene expression at epigenetic, transcriptional, and post-transcriptional levels. Moreover, lncRNAs play pivotal roles in the progression of cardiocerebrovascular diseases. For example, recent studies suggested that abnormal expression of lncRNAs are closely related to the occurrence and progression of these diseases. LncRNAs regulate gene expression by specifically binding to mRNA to modulate disease progression, serving as biomarkers for the diagnosis and prognosis of cardiocerebrovascular diseases. In this review, we discuss the roles, mechanisms, and clinical value of lncRNAs in cardiocerebrovascular diseases, providing a new perspective for the diagnosis and treatment of the diseases.

Long noncoding RNAs in head and neck squamous cell carcinoma: biological functions and mechanisms

Head and neck squamous cell carcinoma (HNSCC) is the primary malignant tumor of the oral cavity, larynx, nasopharynx, esophagus and tongue. Although several novel therapeutic methods for HNSCC have been developed, the final therapeutic effect on the patient is still not satisfactory. Thus, it is imperative that scientists identify novel distinguishable markers with specific molecular characteristics that can be used in therapeutic and prognostic evaluation. Previous reports have shown that long noncoding RNAs (lncRNAs) are important regulators of gene expression in many cancers, including head and neck squamous cell carcinomas. Translational studies of lncRNAs in HNSCC are urgently required before their application as a treatment can be realized. We aimed to address the most relevant findings on lncRNAs as biomarkers or treatment targets in head and neck squamous cell carcinoma and to summarize their discovered pathways and mechanisms of action to reveal the possible future applications of these novel biomarkers in clinical translational research.

LINC00473 contributes to the radioresistance of esophageal squamous cell carcinoma by regulating microRNA‑497‑5p and cell division cycle 25A

Long non-coding RNA (lncRNA) LINC00473 plays a carcinogenic role in a variety of different tumor types. Nevertheless, the mechanisms through which LINC00473 regulates the radiosensitivity of esophageal squamous cell carcinoma (ESCC) cells remains elusive. In the present study, reverse transcription-quantitative PCR was used to quantify the expression of LINC00473, microRNA (miRNA/miR)-497-5p and cell division cycle 25A (CDC25A) in ESCC tissues. The association between LINC00473 expression and the clinicopathological characteristics of patients with ESCC was also assessed. Furthermore, Cell Counting kit-8 and colony formation assays were carried out to monitor the proliferation of ESCC cells exposed to X-ray radiation. A dual-luciferase reporter assay was also conducted to analyze the interaction between LINC00473 and miR-497-5p, as well as the interaction between CDC25A and miR-497-5p. The findings of the present study demonstrated that in ESCC tissues and cells, the expression levels of LINC00473 and CDC25A were significantly upregulated, while the expression of miR-497-5p was downregulated. The high expression level of LINC00473 was associated with a higher T stage, lymph node metastasis stage and a lower tumor differentiation grade in patients with ESCC. Following irradiation, transfection with miR-497-5p mimics reduced the promoting effect of LINC00473 overexpression on ESCC cell proliferation, and partially impeded the resistance of ESCC cells to X-ray radiation induced by LINC00473 overexpression. Moreover, transfection with miR-497-5p inhibitors partially alleviated the inhibitory effects of LINC00473 knockdown on cellular proliferation, and partly reversed the sensitivity of cells to X-ray irradiation induced by LINC00473 knockdown. Furthermore, it was confirmed that miR-497-5p was able to bind LINC00473 and the 3′-untranslated region of CDC25A. On the whole, the findings of the present study demonstrate that LINC00473 reduces the radiosensitivity of ESCC cells by modulating the miR-497-5p/CDC25A axis.

Long noncoding RNA linc00467 plays an oncogenic role in hepatocellular carcinoma by regulating the miR-18a-5p/NEDD9 axis

Increasing evidence has shown that numerous long noncoding RNAs (lncRNAs) play critical roles in tumorigenesis. Herein, we investigated the biological role of lncRNA linc00467 in the cancer biology of hepatocellular carcinoma (HCC). We observed that linc00467 was upregulated in HCC tissues and cells. Silencing of linc00467 using small interfering RNA interference significantly inhibited the growth and motility of HCC cells, and increased cell apoptosis through regulating the Bcl-2/Bax axis and the caspase cascade, suggesting that linc00467 exerted oncogenic functions in the progression of HCC. Moreover, we found that linc00467 could target miR-18a-5p, and NEDD9 was a target for miR-18a-5p in HCC cells. Furthermore, either the miR-18a-5p inhibitor or upregulation of NEDD9 could recover the inhibitory effects caused by silencing of linc00467. In conclusion, our data highlighted the oncogenic role of linc00467 in HCC progression by regulating the miR-18a-5p/NEDD9 axis.

A Long Non-coding RNA Lnc712 Regulates Breast Cancer Cell Proliferation

Great quantity of intergenic noncoding RNAs (lncRNAs) have been identified in the mammalian genome and involved in various biological processes, especially in the development and metastasis of cancer. In this study, we identified one lncRNA, lncRNA NONHSAT028712 (Lnc712), was highly expressed in breast cancer cell lines and tissues based on microarray screening. Knockdown of Lnc712 largely inhibited breast cancer cell proliferation. Mechanistically, Lnc712 bound specifically to heat-shock protein 90 (HSP90). Interaction between Lnc712 and HSP90 is required for HSP90 binding to cell division cycle 37 (Cdc37). The Lnc712/HSP90/Cdc37 complex regulated cyclin-dependent kinase 2 (CDK2) activation and then triggered breast cancer cell proliferation. In summary, our results identified a new lncRNA regulate breast cancer proliferation though interaction with HSP90.

Down-regulation of long non-coding RNA HOTAIR inhibits invasion and migration of oesophageal cancer cells via up-regulation of microRNA-204

Oesophageal cancer is a progressive tumour with high mortality. However, therapies aimed at treating oesophageal cancer remain relatively limited. Accumulating studies have highlighted long non‐coding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR), microRNA‐204 (miR‐204) and homeobox C8 (HOXC8) in the progression of oesophageal cancer. Herein, we tried to demonstrate the function of HOTAIR, miR‐204 and HOXC8 in oesophageal cancer and their relationship. Differentially expressed genes involved in oesophageal cancer were identified. The endogenous expression of HOTAIR and miR‐204 in oesophageal cancer cell lines was altered to elucidate their effects and to identify the interaction among HOTAIR, miR‐204 and HOXC8. We also explored the underlying regulatory mechanisms of HOTAIR and miR‐204 with siRNA against HOTAIR, miR‐204 mimic or miR‐204 inhibitor. Cell proliferation, migration, invasion and apoptosis were subsequently detected. Xenograft in nude mice was induced to evaluate tumourigenicity. miR‐204 was down‐regulated, while HOTAIR and HOXC8 were up‐regulated in the oesophageal cancer tissues. HOTAIR could competitively bind to miR‐204 and miR‐204 could further target HOXC8. The oesophageal cancer cells treated with si‐HOTAIR or miR‐204 mimic exhibited decreased expression levels of HOXC8, Vimentin and MMP‐9, but increased E‐cadherin level. Silenced HOTAIR or elevated miR‐204 inhibited proliferation, migration and invasion, along with stimulated apoptosis of oesophageal cancer cells. In summary, our results show that lncRNA HOTAIR could specifically bind to miR‐204 as a competing endogenous RNA and regulate miR‐204 and HOXC8. Hence, down‐regulation of HOTAIR could inhibit progression of oesophageal cancer, indicating a novel target for oesophageal cancer treatment.

Decreased expression of SPINT1-AS1 and SPINT1 mRNA might be independent unfavorable prognostic indicators in esophageal squamous cell carcinoma

Purpose: The serine peptidase inhibitor, Kunitz type 1 antisense RNA1 (SPINT1-AS1), a long non-coding RNA , has been linked to cancer progression. In this study, we aimed to explore the SPINT1-AS1 expression in matched esophageal squamous cell carcinoma (ESCC) and normal tissues, and analyze the potential correlations of SPINT1-AS1 expression with clinicopathological characteristics, in order to evaluate its prognosis and therapeutic value.

Methods: SPINT1-AS1 expression was detected in 99 cases of matched ESCC and normal tissues samples using the quantitative real-time polymerase chain reaction method.

Results: The expression level (△Ct) of SPINT1-AS1 and SPINT1 mRNA was significantly downregulated in ESCC tissues compared with matched normal tissues (P=0.0005; P=0.0002, respectively), and there was an obvious positive correlation between SPINT1-AS1 and SPINT1 mRNA expression. Clinicopathological characteristics indicated that SPINT1-AS1 expression was correlated with age and tumor size, while SPINT1 mRNA expression was correlated with age and gender. The receiver operating characteristic (ROC) curve analysis of the expression level of SPINT1-AS1 and SPINT1 mRNA yielded an area under the ROC curve value of 0.638 and 0.625, respectively. The overall survival is shorter in patients with low SPINT1-AS1 expressed than those with high levels of SPINT1-AS1 (P=0.044), and SPINT1 mRNA expression level is associated with the OS (P=0.001). Univariate and multivariate analysis suggested that SPINT1-AS1 was an independent prognostic indicator in ESCC.

Conclusions: We found that the expression of SPINT1-AS1 and SPINT1 mRNA is downregulated in ESCC tissues, which could contribute to tumor progression. SPINT1-AS1 and SPINT1 mRNA may be therapeutic targets and prognosis markers for ESCC.

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A seven-long noncoding RNA signature predicts relapse in patients with early-stage lung adenocarcinoma

BACKGROUND

Long noncoding RNA (lncRNA) has been increasingly reported to play crucial roles in cancer development. In this study, we aim to develop a lncRNA-based signature to predict the relapse of early-stage (stage I-II) lung adenocarcinoma (LUAD).

METHODS

With a lncRNA-mining strategy, lncRNA expression profiles of three LUAD cohorts were obtained from the Gene Expression Omnibus database. A risk score model was established based on the lncRNAs expression from training set (GSE31210, n = 204) and further validated in two independent testing sets (GSE50081, n = 124; and GSE30219, n = 84). The potential signaling pathways modulated by the prognostic lncRNAs were explored using bioinformatics analysis.

RESULTS

In the training set, seven lncRNAs were identified to be significantly correlated with the relapse-free survival (RFS) of early-stage LUAD, and were then aggregated to form a seven-lncRNA prognostic signature to classify patients into high-risk and low-risk groups. Individuals of training set in the high-risk group exhibited a poorer RFS than those in the low-risk group (HR: 7.574, 95% CI: 4.165-13.775; P < 0.001). The similar prognostic powers of the seven-lncRNA signature were also achieved in the two independent testing sets and in stratified analysis. Multivariate Cox regression indicated that the prognostic value of seven-lncRNA signature was independent of other clinical features. Functional enrichment analysis found that the seven-lncRNA signature may be involved in biological pathways such as cell cycle, DNA replication, and p53 signaling pathway.

CONCLUSION

Our results indicate that the seven-lncRNA signature may be an innovative biomarker to predict the relapse of early-stage LUAD.

Differential Analysis of lncRNA, miRNA and mRNA Expression Profiles and the Prognostic Value of lncRNA in Esophageal Cancer

Integrative central axis of lncRNA-miRNA-mRNA plays pivotal roles in tumor development and progression. However, the regulatory role of lncRNA-miRNA-mRNA in esophageal cancer remains elusive. TCGA database was utilized to investigate the differential expression of lncRNA, miRNA and mRNA in esophageal cancer (ESCA) and normal esophageal tissues, and GEO database was used to further validate the expression profile of key genes. Differential lncRNAs in TCGA database were submitted to Starbase, and lncRNAs related to overall survival were analyzed using Kaplan-Meier and log-rank test. We found 145 lncRNAs, 112 miRNAs and 2000 protein coding mRNAs were differentially expressed in ESCA samples, which were tightly involved in chromosome segregation, extracellular matrix assembly by GO assay, and KEGG assay revealed the correlation of differentially expressed genes with cell cycle, apoptosis and cGMP-PKG signaling pathway. Furthermore, there were 291 nodes in ceRNA network, which consisted of 40 lncRNAs, 28 miRNAs and 233 mRNAs, and formed 677 relations. Furthermore, 6 of 10 lncRNAs in TCGA database were consistent with GEO database, and expressions of 10 mRNAs in TCGA database all exhibited the same tendency with GEO database. Notably, we found 8 lncRNAs (WDFY3-AS2, CASC8, UGDH-AS1, RAP2C-AS1, AC007128.1, AC016205.1, AC092803.2 and AC079949.2) were correlated with overall survival of the patients with ESCA. The key differentially expressed genes participate in the development and progression of ESCA, and thus the elucidation of functions of lncRNA-miRNA-mRNA will provide new novel therapeutic target for the patients with ESCA.

Transcriptomic model-based lncRNAs and mRNAs serve as independent prognostic indicators in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSC) is one of most common types of cancer worldwide, and mRNAs and long non-coding RNAs (lncRNAs) have been identified as prognostic biomarkers in HNSC. In the present study, using gene expression datasets from multiple platforms, survival-associated genes in HNSC were identified. Subsequently, a combination of 17 genes (14 mRNAs and 3 lncRNA) was optimized using random forest variable hunting and a risk score model for HNSC prognosis was developed using a cohort from The Cancer Genome Atlas. Patients with high-risk scores tend to have earlier disease recurrence and lower survival rates, compared with those with low-risk scores. This observation was further validated in three independent datasets (GSE41613, GSE10300 and E-MTAB-302). Association analysis revealed that the risk score is independent of other clinicopathological observations. On the basis of the results depicted in the nomogram, the risk score performs better in 3-year survival rate prediction than other clinical observations. In summary, the lncRNA-mRNA signature-based risk score successfully predicts the survival of HNSC and serves as an indicator of prognosis.

Prognostic value of long non-coding RNA ZEB1-AS1 in Chinese cancer patients: A Meta-analysis

BACKGROUND

Aberrant expression of long non-coding RNA Zinc finger E-box binding homeobox 1 antisense 1 (lncRNA ZEB1-AS1) can be detected in numerous malignancies. Therefore, a meta-analysis had been carried out in this study, aiming to examine the prognostic value of lncRNA ZEB1-AS1 in malignancies.

METHODS

Electronic databases, such as PubMed, OVID as well as Web of Science, had been systemically retrieved from inception to February 14th, 2019. Besides, the hazard ratios (HRs), together with the corresponding 95% confidence intervals (CIs), had also been analyzed for determining the association of lncRNA ZEB1-AS1 expression with the overall survival (OS) and recurrence-free survival (RFS). In addition, the pooled odds ratios (ORs) would also be computed using the Stata SE12.0 software for evaluating the relationship of lncRNA ZEB1-AS1 expression with pathological factors.

RESULTS

A total of 21 original studies involving 1801 cancer patients had been enrolled into the current meta-analysis. As suggested by the pooled HR, high expression of lncRNA ZEB1-AS1 had displayed marked correlation with OS (HR = 2.16, 95% CI: 1.89-2.47) among cancer patients, and no significant heterogeneity was detected. Additionally, high expression of lncRNA ZEB1-AS1 was also markedly associated with RFS among cancer patients (pooled HR = 2.55, 95% CI: 1.61-4.03). Besides, the expression of lncRNA ZEB1-AS1 had displayed marked correlation with poor histological grade (PHG) (OR = 2.86, 95% CI: 2.11-3.87), high tumor stage (HTS) (OR = 3.81, 95% CI: 2.72-5.34) as well as lymph node metastasis (LNM) (OR = 3.33, 95% CI: 2.47-4.49). Additionally, no distinct asymmetry had been detected for RFS, PHG as well as HTS based on Begg funnel plot.

CONCLUSIONS

Taken together, high expression of lncRNA ZEB1-AS1 can predict the dismal OS, RFS, LNM, PHG, and HTS, indicating that lncRNA ZEB1-AS1 can be potentially used as a new biomarker to predict the dismal prognosis for cancer patients.

Upregulated long-non-coding RNA DLEU2 exon 9 expression was an independent indicator of unfavorable overall survival in patients with esophageal adenocarcinoma

In this study, we aimed to explore the expression profiles of some known functional lncRNAs in esophageal adenocarcinoma (EAD) and to screening the potential prognostic makers, using data from The Cancer Genome Atlas (TCGA)-esophageal carcinoma (ESCA). Results showed that DLEU2 is a high potential OS related marker among 73 functional lncRNAs. DLEU2 and its intronic miR-15a and miR-16-1 expression were significantly upregulated in EAD compared with adjacent normal tissues. However, miR-15a and miR-16-1 expression were only weakly correlated with DLEU2 expression. Univariate and multivariate analysis confirmed that DLEU2 expression, but not miR-15a or miR-16-1 expression is an independent prognostic marker in terms of OS (HR:1.688, 95%CI: 1.085-2.627, p = 0.020) in EAD patients. The exon 9 of DLEU2 is very strongly co-expressed with DLEU2 (Pearson's r = 0.96) and showed better predictive value than total DLEU2 expression in predicting the OS of EAD patients. Multivariate analysis confirmed its independent prognostic value (HR:1.970, 95%CI: 1.266-3.067, p = 0.003), after adjustment of histologic grade, pathological stages and the presence of residual tumor. By checking the methylation status of DLEU2 gene, we excluded the possibility of the influence of two CpG sites near the DLEU2 exon 9 locus on its expression. In addition, although copy number alterations (CNAs) were observed DLEU2 gene, heterozygous loss (-1), low-level copy gain (+1) and high-level amplification (+2) had no significant association with DLEU2 transcription. Based on these findings, we infer that DLEU2 exon 9 expression might serve as a valuable biomarker of unfavorable OS in EAD patients.

Knockdown of Long Noncoding RNA POU5F1B Promotes Radiosensitivity in Esophageal Carcinoma

BACKGROUND POU5F1B, serving as a carcinogen, participates in radiosensitivity of several tumors. However, in esophageal cancer, its potential mechanism and function in regulating radiosensitivity remain unclear. MATERIAL AND METHODS The expression level of POU5F1B was detected in plasma of esophageal tumor patients and cancer cell lines. The effect of POU5F1B knockdown on cell proliferation and colony formation was determined using CCK-8 assay and colony formation assay. Cell apoptosis rate was detected by flow cytometry. RESULTS POU5F1B expression level declined after radiotherapy in the plasma of esophageal cancer patients (p=0.025). Compared with HEEPIC, the level of POU5F1B was upregulated in ECA109 (p<0.01), ECA9706 (p<0.01), KYSE410 (p<0.01), and KYSE510 (p=0.036). The silencing of POU5F1B played a role in inhibiting colony formation. After radiotherapy, the apoptosis rates in the ECA109 with 4Gy si-POU5F1B group and 4Gy si-NC group were 39.1±0.1% and 35.3±0.1%, respectively (p=0.0193). The rate was 21.00±0.1 and 29.1±0.1% (p<0.0072) in the si-NC group and si-POU5F1B group, respectively. For proliferation rate, 4Gy si-POU5F1B ECA109 performed better than 4Gy si-NC. CONCLUSIONS Radiotherapy contributed to the decline in the expression level of POU5F1B in plasma, which was upregulated in ECA109, ECA9706, KYSE410, and KYSE510, but not in HEEPIC. The knockdown of POU5F1B increased the radiosensitivity of esophageal cancer cell lines.

BC200 RNA: An Emerging Therapeutic Target and Diagnostic Marker for Human Cancer

One of the most interesting findings from genome-wide expression analysis is that a considerable amount of noncoding RNA (ncRNA) is present in the cell. Recent studies have identified diverse biological functions of ncRNAs, which are expressed in a much wider array of forms than proteins. Certain ncRNAs associated with diseases, in particular, have attracted research attention as novel therapeutic targets and diagnostic markers. BC200 RNA, a 200-nucleotide ncRNA originally identified as a neuron-specific transcript, is abnormally over-expressed in several types of cancer tissue. A number of recent studies have suggested mechanisms by which abnormal expression of BC200 RNA contributes to the development of cancer. In this article, we first provide a brief review of a recent progress in identifying functions of BC200 RNA in cancer cells, and then offer examples of other ncRNAs as new therapeutic targets and diagnostic markers for human cancer. Finally, we discuss future directions of studies on BC200 RNA for new cancer treatments.

Genome-wide analysis of long non-coding RNAs in esophageal squamous cell carcinoma reveals their potential role in invasion and metastasis

Background

A high lymphatic metastasis rate and strong local invasive ability are the key characteristics of esophageal squamous cell carcinoma (ESCC) that affect patient survival, and long non‐coding RNAs (lncRNAs) may play a crucial role. We performed genome‐wide analysis of lncRNAs to identify novel biomarkers associated with local invasion and lymphatic metastasis in ESCC.

Methods

Six pairs of ESCC tumor and para‐tumor tissues were subjected to microarray analysis to identify differentially expressed lncRNAs, and 25 pairs of tissues samples were used to verify the effectiveness of screened lncRNAs using quantitative reverse transcription PCR. The correlations between verified lncRNAs and clinicopathological characteristics were analyzed to confirm specific lncRNAs associated with the local invasion and lymphatic metastasis of ESCC, and gene co‐expression analysis was used to predict potential mechanisms.

Results

Microarray analysis identified 1850 lncRNAs with significant differential expression in ESCC. Of 22 lncRNAs selected for quantitative reverse transcription PCR verification, four were significantly upregulated and one was significantly downregulated in ESCC cancer compared to para‐cancer tissues. ENST00000508406.1 was significantly associated with T, N, and tumor node metastasis stages, and NR_037652.1 was significantly associated with N stage. Moreover, 49 lncRNA‐messenger RNA pairs were significantly associated with the two dysregulated lncRNAs and possibly involved in the regulation of local invasion and lymphatic metastasis of ESCC.

Conclusion

The present genome‐wide analysis identified two novel and tumor‐specific lncRNAs for predicting ESCC local invasion and lymphatic metastasis, providing insight into the potential underlying mechanism, which warrants further investigation.

Upregulated long noncoding RNA LINC01296 indicates a dismal prognosis for pancreatic ductal adenocarcinoma and promotes cell metastatic properties by affecting EMT

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a fatal disease that responds poorly to chemotherapy and radiotherapy and whose incidence has increased worldwide. Long noncoding RNAs have been demonstrated to play important roles in cancer initiation and progression. Long intergenic non-coding RNA 01296 (LINC01296) has been reported to be upregulated in several malignancies, but the clinical relevance and biological role of LINC01296 in PDAC are still unclear.

METHODS

RT-qPCR was performed to evaluate the expression of LINC01296 in 85 pared PDAC tissue samples and a panel of PDAC cell lines. The clinical value and prognostic role of LINC01296 in patients with PDAC were further explored. Furthermore, we explored the functional roles of LINC01296 depletion in PANC-1 and SW1990 cells, including cell proliferation, apoptosis, migration, invasion, and epithelial-to-mesenchymal transition (EMT).

RESULTS

LINC01296 was enhanced in PDAC tissues and cell lines, and this overexpression was correlated with advanced tumor stages and positive lymph node metastasis in patients with PDAC. In addition, upregulation of LINC01296 was an independent prognostic predictor for patients with PDAC after surgery. Moreover, silencing of LINC01296 followed by treatment with small interfering RNAs suppressed cell proliferation and promoted cell apoptosis by affecting the Bcl-2/caspase-3 pathway. Importantly, LINC01296 attenuation impaired the migratory and invasive potential partly by reversing EMT.

CONCLUSIONS

Overall, our work may help to develop a novel prognostic biomarker and therapeutic target for PDAC.

LncRNA-ECM is overexpressed in esophageal squamous cell carcinoma and promotes tumor metastasis

The aim of the present study was to investigate the expression of long non-coding(lnc) RNA-extracellular matrix (ECM) in esophageal squamous cell carcinoma (ESCC) and its effect on ESCC metastasis. Using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), the expression of lncRNA-ECM in ESCC tissues was investigated and compared with that in corresponding adjacent tissues. In addition, the expression of lncRNA-ECM in the human ESCC cell lines TE-1, EC9706, KYSE150, Eca109 and KYSE30 was also detected and compared with that in the normal esophageal mucosal epithelial cell line HET-1A. The clinicopathological association between lncRNA-ECM and ESCC was assessed. Silencing and overexpression of lncRNA-ECM in ESCC TE-1 and Eca109 cells determined the correlation between lncRNA-ECM expression and ESCC invasion and metastasis. The possible target genes of lncRNA-ECM were predicted and verified by bioinformatics analysis and experimental results. The expression level of intercellular adhesion molecule 1 (ICAM1) was detected in ESCC tissues by RT-qPCR and the correlation between the expression of ICAM1 and lncRNA-ECM was analyzed. Changes in the expression of ICAM1 in ESCC TE-1 and Eca109 cell lines were evaluated after knocking down lncRNA-ECM and transfection of lncRNA-ECM overexpression plasmids. The expression level of lncRNA-ECM in the tissues of ESCC with lymph node metastasis were significantly increased compared with ESCC with no lymph metastasis (P<0.05). LncRNA-ECM silencing notably reduced the invasion and metastasis of TE-1 and Eca109 cells, while lncRNA-ECM overexpression promoted the invasion and metastasis of the two cell lines. The expression level of ICAMI was directly correlated with the expression of lncRNA-ECM, suggesting that ICAM1 may be the downstream target gene of lncRNA-ECM. LncRNA-ECM was revealed as being overexpressed in ESCC. LncRNA-ECM expression was positively correlated with metastasis and may affect the metastasis of ESCC through ICAMI regulation. These findings indicate that lncRNA-ECM may be promising as a novel biomarker for the diagnosis and prediction of prognosis for ESCC, and it may also serve as a novel therapeutic target for ESCC.

Novel long noncoding RNA NMR promotes tumor progression via NSUN2 and BPTF in esophageal squamous cell carcinoma

Long noncoding RNAs (lncRNA) have been implicated in cancer but most of them remain largely unstudied. Here, we identified a novel NSUN2 methylated lncRNA (NMR), which was significantly upregulated in esophageal squamous cell carcinoma (ESCC), functioned as a key regulator of ESCC tumor metastasis and drug resistance. Upregulation of NMR correlated with tumor metastasis and indicated poor overall survival in ESCC patients. Functionally, NMR could promote tumor cell migration and invasion, inhibit cisplatin-induced apoptosis and increase drug resistance in ESCC cells. Mechanistically, transcription of NMR could be upregulated by NF-κB activation after IL-1β and TNF-α treatment. NMR was methylated by NSUN2 and might competitively inhibit methylation of potential mRNAs. NMR could directly bind to chromatin regulator BPTF, and potentially promote MMP3 and MMP10 expression by ERK1/2 pathway through recruiting BPTF to chromatin. Taken together, NMR functions as an oncogenic gene and may serve as new biomarker and therapeutic target in ESCC.

Long non-coding RNA MIAT in development and disease: a new player in an old game

Background

Long non-coding RNAs (lncRNAs), which are a portion of non-protein-coding RNAs (ncRNAs), have manifested a paramount role in the pathophysiology of human diseases, particularly in pathogenesis and progression of disease.

Main body of the abstract

Myocardial infarction associated transcript (MIAT), which was recently found to demonstrate aberrant expression in various diseases, such as myocardial infarction, schizophrenia, ischemic stroke, diabetic complications, age-related cataract and cancers, is a novel disease-related lncRNA. This work summarize current evidence regarding the biological functions and underlying mechanisms of lncRNA MIAT during disease development.

Short conclusion

LncRNA MIAT likely represents a feasible cancer biomarker or therapeutic target.

Long non-coding RNA PVT1: Emerging biomarker in digestive system cancer

The digestive system cancers are leading cause of cancer-related death worldwide, and have high risks of morbidity and mortality. More and more long non-coding RNAs (lncRNAs) have been studied to be abnormally expressed in cancers and play a key role in the process of digestive system tumour progression. Plasmacytoma variant translocation 1 (PVT1) seems fairly novel. Since 1984, PVT1 was identified to be an activator of MYC in mice. Its role in human tumour initiation and progression has long been a subject of interest. The expression of PVT1 is elevated in digestive system cancers and correlates with poor prognosis. In this review, we illustrate the various functions of PVT1 during the different stages in the complex process of digestive system tumours (including oesophageal cancer, gastric cancer, colorectal cancer, hepatocellular carcinoma and pancreatic cancer). The growing evidence shows the involvement of PVT1 in both proliferation and differentiation process in addition to its involvement in epithelial to mesenchymal transition (EMT). These findings lead us to conclude that PVT1 promotes proliferation, survival, invasion, metastasis and drug resistance in digestive system cancer cells. We will also discuss PVT1's potential in diagnosis and treatment target of digestive system cancer. There was a great probability PVT1 could be a novel biomarker in screening tumours, prognosis biomarkers and future targeted therapy to improve the survival rate in cancer patients.

Long noncoding RNA NNT-AS1 promotes hepatocellular carcinoma progression and metastasis through miR-363/CDK6 axis

Long non-coding RNAs (lncRNAs) have been tested to act as important regulator in liver cancer genesis and progression. LncRNA Nicotinamide Nucleotide Transhydrogenase-antisense RNA1 (NNT-AS1) has been reported to participate in the tumorigenesis. However, the exact molecular mechanism of NNT-AS1 in hepatocellular carcinoma (HCC) is still unknown. In present study, our team identified the up-regulated expression of NNT-AS1 in HCC tissue and cell lines compared with adjacent noncancerous tissue and normal cells. Moreover, HCC patients with high NNT-AS1 levels had poor prognosis than that with low NNT-AS1 level (p=0.0089). In vitro, gain- and loss-of-function experiments revealed that enhanced NNT-AS1 expression promoted the proliferation ability and alleviated the cycle arrest and apoptosis, while NNT-AS1 knockdown suppressed the proliferation and induced G0/G1 phase arrest and apoptosis. In vivo, NNT-AS1 knockdown inhibited the HCC neoplastic tumor volume and weight. Bioinformatics analysis and luciferase reporter assay validated that miR-363 targeted NNT-AS1 and CDK6 3’-UTR. MiR-363 was down-regulated in HCC tissue and cells. NNT-AS1 competed with CDK6 for miR-363 binding and could increase CDK6 expression. In summary, our results suggest the oncogenic role of NNT-AS1 in HCC tumorigenesis through miR-363/CDK6 axis, providing a novel therapeutic target for human HCC.

PTENP1 inhibits the growth of esophageal squamous cell carcinoma by regulating SOCS6 expression and correlates with disease prognosis

PTEN pseudogene (PTENP1) has a tumor suppressive role in multiple cancers. However, its involvement in esophageal squamous cell carcinoma (ESCC) remains largely unknown. In this study, we set out to identify the role of PTENP1 in the development of ESCC. Gene Expression Omnibus database was employed to investigate the expression of PTENP1 in ESCC. sRNA target Database (StarBase v2.0) was used to query the downstream of PTENP1. Next, both in vitro and in vivo experiments were employed to explore the function. Cell proliferation was evaluated by CCK‐8, soft agar, and colony formation assays. Expression of relative genes was assessed by quantitative real‐time PCR (qRT‐PCR) and Western blotting. 3′UTR luciferase assay was used to confirm the miRNA binding. The clinical significance of PTENP1 was further validated by immunohistochemistry (IHC) and correlation with clinicopathological indicators in additional samples (n = 93). We found expression of PTENP1 in ESCC was lower than that in the corresponding adjacent normal tissues (n = 17). Overexpression of PTENP1 in Eca109 and TE‐1 cells resulted in inhibited proliferation and altered expression of SOCS6‐p‐STAT3‐HIF‐1α pathway both in vitro and in vivo. Subsequent IHC reported a similar trend in human ESCC samples. 3′UTR luciferase assay demonstrated that PTENP1 3′UTR decoyed miR‐17‐5p from binding to SOCS6. Moreover, PTENP1 expression was correlated with clinicopathological indicators to varying degrees, including histological grade, TNM stage, infiltration depth, lymph node metastasis, and overall survival. Taken together, these results suggested an anti‐oncogenic role of PTENP1. Meanwhile, PTENP1 may also serve as a candidate of prognostic indicator for ESCC patients.

Long noncoding RNA HOTTIP as an independent prognostic marker in cancer

BACKGROUND

It has been reported that HOXA transcript at the distal tip (HOTTIP) is dysregulated in various cancers. We performed this meta-analysis to clarify its promising functions as a prognosis marker in malignant tumors.

METHODS

The electronic databases, including PubMed, Medline, OVID, Cochrane Library, and Web of Science were searched from inception to September 23, 2016. The hazard ratio (HR) and 95% confidence interval (CI) were calculated to explore the relationship between HOTTIP expression and overall survival (OS), which were extracted from the eligible studies. The odds ratio (OR) was calculated to assess the association between HOTTIP expression and pathological parameters by using RevMan5.3 software.

RESULTS

Seven studies were included in the study, with a total of 652 patients. The pooled HR suggested that high HOTTIP expression was significantly correlated with poor OS (HR=2.16, 95% CI: 1.69-2.76, P<0.00001) in cancer patients without obvious heterogeneity. The results showed there was a significant difference in the incidence of lymph node metastasis (LNM) between high HOTTIP expression group and low HOTTIP expression group (OR=2.30, 95% CI: 1.58-3.35, P<0.0001). A similar result was observed in the association between HOTTIP expression and distant metastasis (DM), the odds ratio was 3.30 (95% CI: 1.78-6.12, P=0.0001) without obvious heterogeneity. In addition, high HOTTIP expression was significantly associated with high tumor stage (OR=3.30, 95% CI: 0.25-0.64) without heterogeneity.

CONCLUSIONS

This meta-analysis demonstrated that high HOTTIP expression significantly predicts poor OS, lymph node metastasis, distant metastasis and tumor stage, suggesting that high HOTTIP expression may serve as a novel biomarker for poor prognosis in cancers.

Long non-coding RNA TUG1 as a potential prognostic biomarker in human cancers: a meta-analysis

LncRNA taurine upregulated gene 1 (TUG1) is reportedly dysregulated in various cancers. We performed this meta-analysis to clarify the usefulness of TUG1 as a prognostic marker in malignant tumors. The PubMed, Medline, OVID, Cochrane Library, and Web of Science databases were searched from inception to Jan 11, 2017. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to explore the relationship between TUG1 expression and overall survival (OS). Odds ratios (ORs) were calculated to assess the association between TUG1 expression and pathological parameters. Thirteen original studies covering 1,274 cancer patients were included in this meta-analysis. The pooled HR suggested that high TUG1 expression correlated with poor OS (pooled HR=1.41, 95% CI: 1.01-1.98) in cancer types other than non-small cell lung cancer. TUG1 expression was also related to distant metastasis (OR=3.24, 95% CI: 1.18-8.93), large tumor size (OR=4.07, 95% CI: 1.08-15.28) and advanced tumor stage (OR=3.45, 95% CI: 2.19-5.44). Begg’s funnel plot and Egger’s test showed no evidence of obvious asymmetry for overall survival or tumor stage. Thus high TUG1 expression appears predictive of poor OS, distant metastasis, advanced tumor stage and large tumor size. This suggests TUG1 expression could serve as a biomarker for poor prognosis in cancers.

The global expression profiling in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the dominant subtype of esophageal cancer worldwide. This study aimed to explore the aberrant global expression profiling and construct regulatory network in ESCC for understanding tumorigenesis of ESCC. The expression pattern of long non-coding RNA (lncRNA), microRNA (miRNA) and mRNA was measured by RNA-sequencing in ESCC. Differentially expressed lncRNAs/miRNAs/mRNAs (DELs/DEMs/DEMIs) were identified in ESCC. DEMIs-DEMs network was constructed; hsa-miR-424-5p and hsa-miR-450b-5p were the hub miRNAs in the network, which negatively regulated 19 and 17 DEMs. DEMs targeted by DEMIs were significantly enriched in MAPK signaling pathway, pathways in cancer and focal adhesion signaling pathway. The expression of candidate DEMs and DEMIs in ESCC were validated through quantitative real-time polymerase chain reaction and microarray expression profiling analyses, and the results were generally consistent with our bioinformatics analysis. Our results might provide useful information for exploring the tumorigenesis mechanism and potentially therapeutic targets in ESCC.

Seven LncRNA-mRNA based risk score predicts the survival of head and neck squamous cell carcinoma

Dysregulation of mRNAs and long non-coding RNAs (lncRNAs) is one of the most important features of carcinogenesis and cancer development. However, studies integrating the expression of mRNAs and lncRNAs to predict the survival of head and neck squamous cell carcinoma (HNSC) are still limited, hitherto. In current work, we identified survival related mRNAs and lncRNAs in three datasets (TCGA dataset, E-TABM-302, GSE41613). By random forest, seven gene signatures (six mRNAs and lncRNA) were further selected to develop the risk score model. The risk score was significantly associated with survival in both training and testing datasets (E-TABM-302, GSE41613, and E-MTAB-1324). Furthermore, correlation analyses showed that the risk score is independent from clinicopathological features. According to Cox multivariable hazard model and nomogram, the risk score contributes the most to survival than the other clinical information, including gender, age, histologic grade, and alcohol taking. The Gene Set Enrichment Analysis (GSEA) indicates that the risk score is associated with cancer related pathways. In summary, the lncRNA-mRNA based risk score model we developed successfully predicts the survival of 755 HNSC samples in five datasets and two platforms. It is independent from clinical information and performs better than clinical information for prognosis.