Long non-coding RNA: A newly deciphered "code" in prostate cancer

LncRNA PART1 promotes malignant biological behaviours associated with head and neck cancer cells via synergistic action with FUT6

The aim of this study was to determine the role of lncRNA PART1 and downstream FUT6 in tumorigenesis and progression of head and neck cancer (HNC). Bioinformatics analysis and qRT-PCR revealed that lncRNA PART1 was expressed at low levels in HNC patients. The proliferation, apoptosis, migration and flow cytometry results showed that low expression of lncRNA PART1 inhibited apoptosis and promoted HNC cell migration and proliferation. In addition, animal experiments have also shown that low expression of lncRNA PART1 can promote tumor growth. LncRNA PART1 overexpression promoted apoptosis and inhibited HNC cell migration and proliferation. Through bioinformatics analysis, FUT6 was found to be expressed at low levels in HNC and to be correlated with patient survival. Immunohistochemical and qRT-PCR results revealed that FUT6 was underexpressed in tumour tissues and HNC cells. Cell and animal experiments showed that overexpression of FUT6 could inhibit tumour proliferation and migration. Bioinformatics analysis revealed that lncRNA PART1 was positively correlated with FUT6. By qRT-PCR and western blot, we observed that after knockdown of lncRNA PART1, both the mRNA and protein expression levels of FUT6 were reduced. The above results indicated that lncRNA PART1 and FUT6 play an important role in HNC, and that lncRNA PART1 affected the development of tumor by downstream FUT6.

Lineage Plasticity and Stemness Phenotypes in Prostate Cancer: Harnessing the Power of Integrated "Omics" Approaches to Explore Measurable Metrics

Prostate cancer (PCa), the most frequent and second most lethal cancer type in men in developed countries, is a highly heterogeneous disease. PCa heterogeneity, therapy resistance, stemness, and lethal progression have been attributed to lineage plasticity, which refers to the ability of neoplastic cells to undergo phenotypic changes under microenvironmental pressures by switching between developmental cell states. What remains to be elucidated is how to identify measurements of lineage plasticity, how to implement them to inform preclinical and clinical research, and, further, how to classify patients and inform therapeutic strategies in the clinic. Recent research has highlighted the crucial role of next-generation sequencing technologies in identifying potential biomarkers associated with lineage plasticity. Here, we review the genomic, transcriptomic, and epigenetic events that have been described in PCa and highlight those with significance for lineage plasticity. We further focus on their relevance in PCa research and their benefits in PCa patient classification. Finally, we explore ways in which bioinformatic analyses can be used to determine lineage plasticity based on large omics analyses and algorithms that can shed light on upstream and downstream events. Most importantly, an integrated multiomics approach may soon allow for the identification of a lineage plasticity signature, which would revolutionize the molecular classification of PCa patients.

Sparse Independence Component Analysis for Competitive Endogenous RNA Co-Module Identification in Liver Hepatocellular Carcinoma

OBJECTIVE

Long non-coding RNAs (lncRNAs) have been shown to be associated with the pathogenesis of different kinds of diseases and play important roles in various biological processes. Although numerous lncRNAs have been found, the functions of most lncRNAs and physiological/pathological significance are still in its infancy. Meanwhile, their expression patterns and regulation mechanisms are also far from being fully understood.

METHODS

In order to reveal functional lncRNAs and identify the key lncRNAs, we develop a new sparse independence component analysis (ICA) method to identify lncRNA-mRNA-miRNA expression co-modules based on the competitive endogenous RNA (ceRNA) theory using the sample-matched lncRNA, mRNA and miRNA expression profiles. The expression data of the three RNA combined together is approximated sparsely to obtain the corresponding sparsity coefficient, and then it is decomposed by using ICA constraint optimization to obtain the common basis and modules. Subsequently, affine propagation clustering is used to perform cluster analysis on the common basis under multiple running conditions to obtain the co-modules for the selection of different RNA elements.

RESULTS

We applied sparse ICA to Liver Hepatocellular Carcinoma (LIHC) dataset and the experiment results demonstrate that the proposed sparse ICA method can effectively discover biologically functional expression common modules.

CONCLUSION

It may provide insights into the function of lncRNAs and molecular mechanism of LIHC. Clinical and Translational Impact Statement-The results on LIHC dataset demonstrate that the proposed sparse ICA method can effectively discover biologically functional expression common modules, which may provide insights into the function of IncRNAs and molecular mechanism of LIHC.

Liquid Biopsy for Cancer Cachexia: Focus on Muscle-Derived microRNAs

Cancer cachexia displays a complex nature in which systemic inflammation, impaired energy metabolism, loss of muscle and adipose tissues result in unintentional body weight loss. Cachectic patients have a poor prognosis and the presence of cachexia reduces the tolerability of chemo/radio-therapy treatments and it is frequently the primary cause of death in advanced cancer patients. Early detection of this condition could make treatments more effective. However, early diagnostic biomarkers of cachexia are currently lacking. In recent years, although solid biopsy still remains the "gold standard" for diagnosis of cancer, liquid biopsy is gaining increasing interest as a source of easily accessible potential biomarkers. Moreover, the growing interest in circulating microRNAs (miRNAs), has made these molecules attractive for the diagnosis of several diseases, including cancer. Some muscle-derived circulating miRNA might play a pivotal role in the onset/progression of cancer cachexia. This topic is of great interest since circulating miRNAs might be easily detectable by means of liquid biopsies and might allow an early diagnosis of this syndrome. We here summarize the current knowledge on circulating muscular miRNAs involved in muscle atrophy, since they might represent easily accessible and promising biomarkers of cachexia.

Integrated Analysis of a Competing Endogenous RNA Network Reveals a Prognostic lncRNA Signature in Bladder Cancer

Long non-coding RNAs (lncRNAs) act as competing endogenous RNAs (ceRNAs) to regulate mRNA expression through sponging microRNA in tumorigenesis and progression. However, following the discovery of new RNA interaction, the differentially expressed RNAs and ceRNA regulatory network are required to update. Our study comprehensively analyzed the differentially expressed RNA and corresponding ceRNA network and thus constructed a potentially predictive tool for prognosis. “DESeq2” was used to perform differential expression analysis. Two hundred and six differentially expressed (DE) lncRNAs, 222 DE miRNAs, and 2,463 DE mRNAs were found in this study. The lncRNA-mRNA interactions in the miRcode database and the miRNA-mRNA interactions in the starBase, miRcode, and mirTarBase databases were searched, and a competing endogenous RNA (ceRNA) network with 186 nodes and 836 interactions was subsequently constructed. Aberrant expression patterns of lncRNA NR2F1-AS1 and lncRNA AC010168.2 were evaluated in two datasets (GSE89006, GSE31684), and real-time polymerase chain reaction was also performed to validate the expression pattern. Furthermore, we found that these two lncRNAs were independent prognostic biomarkers to generate a prognostic lncRNA signature by univariate and multivariate Cox analyses. According to the lncRNA signature, patients in the high-risk group were associated with a poor prognosis and validated by an external dataset. A novel genomic-clinicopathologic nomogram to improve prognosis prediction of bladder cancer was further plotted and calibrated. Our study deepens the understanding of the regulatory ceRNA network and provides an easy-to-do genomic-clinicopathological nomogram to predict the prognosis in patients with bladder cancer.

A high level of lncFGD5-AS1 inhibits epithelial-to-Mesenchymal transition by regulating the miR-196a-5p/SMAD6/BMP axis in gastric Cancer

Background

Long non-coding RNA (lncRNA) was a vital factor in the progression and initiation of human cancers. This study found a new lncRNA, FGD5-AS1, which can inhibit EMT process, proliferation, and metastasis in vitro and in vivo.

Methods

qRT-PCR was employed to test the expression of lncFGD5-AS1 in 30 gastric cancer patients’ cancer tissue and para-cancer tissue. Overexpressed lncFGD5-AS1 cells shown sharply decrease of proliferation, migration, and epithelial-mesenchymal transition (EMT). miR-196a-5p/SMAD6 was confirmed as downstream molecular mechanism of lncFGD5-AS1 by expression correlation analysis and mechanism experiments. In vivo study illustrated overexpression of lncFGD5-AS1 suppression tumor growth.

Results

LncFGD5-AS1 served as a ceRNA of miR-196a-5p to release its inhibition on SMAD6, a conventional inhibitor on the BMP pathway. Comparing with normal gastric cancer cells, FGD5-AS1 overexpressed group had fewer migration cells, lower cell viability, and lower EMT transformation rate. Meanwhile, xenografts nude mice injecting with overexpressed-FGD5-AS1 cells also shown smaller tumor weight and volume.

Conclusion

In conclusion, this research supported the first evidence that FGD5-AS1 suppressed proliferation and metastasis in gastric cancer by regulating miR-196a-5p/SMAD6/BMP axis and suggested a potential therapeutic candidate for gastric cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08192-x.

Long non-coding RNA PRNCR1 modulates non-small cell lung cancer cell proliferation, apoptosis, migration, invasion, and EMT through PRNCR1/miR-126-5p/MTDH axis

Background: Non-small cell lung cancer (NSCLC) is a highly malignant tumor. Accumulating evidence suggested that prostate cancer non-coding RNA 1 (PRNCR1) participated in the pathogenesis of NSCLC, whereas the elaborate mechanism remains unclear. Hence, the role of PRNCR1 in the progression of NSCLC was investigated.

Methods: Levels of PRNCR1, microRNA-126-5p (miR-126-5p), and metadherin (MTDH) were examined by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was measured using Cell Counting Kit-8 (CCK-8). Flow cytometry was conducted to determine cell apoptosis. Besides, transwell assay was performed to detect cell migration and invasion in NSCLC cells. The expression levels of E-cadherin, N-cadherin, Vimentin, and MTDH were detected via Western blot. Dual-luciferase reporter, RNA immunoprecipitation, and RNA pull down assays were employed to verify the relationship between miR-126-5p and PRNCR1 or MTDH.

Results: PRNCR1 and MTDH levels were highly expressed, while miR-126-5p expression was lowly expressed in NSCLC tissues and cell lines. Knockdown of PRNCR1 promoted cell apoptosis, impeded proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) in NSCLC cells, and these effects were abrogated by its target gene of miR-126-5p inhibitor. Moreover, MTDH as the target of PRNCR1, its overexpression reversed the impacts of miR-126-5p mimic on cell behaviors and EMT in vitro. Finally, PRNCR1 and miR-126-5p regulated MTDH expression.

Conclusion: PRNCR1 modified cell behaviors and EMT via miR-126-5p/MTDH axis in NSCLC cells, providing a novel thinking for clinical treatment of NSCLC.

Transcriptomic Analysis of LNCaP Tumor Xenograft to Elucidate the Components and Mechanisms Contributed by Tumor Environment as Targets for Dietary Prostate Cancer Prevention Studies

LNCaP athymic xenograft model has been widely used to allow researchers to examine the effects and mechanisms of experimental treatments such as diet and diet-derived cancer preventive and therapeutic compounds on prostate cancer. However, the biological characteristics of human LNCaP cells before/after implanting in athymic mouse and its relevance to clinical human prostate outcomes remain unclear and may dictate interpretation of biological efficacies/mechanisms of diet/diet-derived experimental treatments. In this study, transcriptome profiles and pathways of human prostate LNCaP cells before (in vitro) and after (in vivo) implanting into xenograft mouse were compared using RNA-sequencing technology (RNA-seq) followed by bioinformatic analysis. A shift from androgen-responsive to androgen nonresponsive status was observed when comparing LNCaP xenograft tumor to culture cells. Androgen receptor and aryl-hydrocarbon pathway were found to be inhibited and interleukin-1 (IL-1) mediated pathways contributed to these changes. Coupled with in vitro experiments modeling for androgen exposure, cell-matrix interaction, inflammation, and hypoxia, we identified specific mechanisms that may contribute to the observed changes in genes and pathways. Our results provide critical baseline transcriptomic information for a tumor xenograft model and the tumor environments that might be associated with regulating the progression of the xenograft tumor, which may influence interpretation of diet/diet-derived experimental treatments.

LncRNA PRNCR1 Promotes Breast Cancer Proliferation and Inhibits Apoptosis by Modulating microRNA-377/CCND2/MEK/MAPK Axis

BACKGROUND

Long non-coding RNAs (lncRNAs) have recently become the vital gene regulators in diverse cancers. In our study, we purposed to inquiry into the mechanisms of lncRNA PRNCR1 in breast cancer via microRNA-377 (miR-377)/CCND2/MEK/MAPK axis.

METHODS

PRNCR1 expression in breast cancer tissues was detected, and the correlation between PRNCR1 expression and prognostic survival was analyzed. The expressions of PRNCR1 and miR-377 in breast cancer cell lines were detected. Relationships among PRNCR1, miR-377 and CCND2 were confirmed by luciferase activity, RNA pull-down or RIP assays. Breast cancer cells were introduced with silenced PRNCR1 or restored miR-377 to explore their functions in malignant phenotype of breast cancer cells. The expression of MEK/MAPK pathway-related proteins was determined by western blot analysis.

RESULTS

PRNCR1 was highly expressed and miR-377 was poorly expressed in patients with breast cancer, and patients with high expression of PRNCR1 had a poor prognosis. PRNCR1 silencing or miR-377 overexpression resulted in suppressed breast cancer cell proliferation ability, blocked cell cycle process and induced apoptosis. PRNCR1 regulated CCND2 expression by competitively binding to miR-377. CCND2 activated the MEK/MAPK pathway, and after treatment with Mirdametinib, the MEK/MAPK pathway was inhibited, which was found to retard breast cancer growth.

CONCLUSION

Our study highlights that lncRNA PRNCR1 may competitively bind to miR-377, leading to upregulated CCND2, which in turn activated MEK/MAPK pathway to promote breast cancer growth.

LncRNA CBR3-AS1 regulates of breast cancer drug sensitivity as a competing endogenous RNA through the JNK1/MEK4-mediated MAPK signal pathway

Background

Adriamycin (ADR) resistance is one of the main obstacles to improving the clinical prognosis of breast cancer patients. Long noncoding RNAs (lncRNAs) can regulate cell behavior, but the role of these RNAs in the anti-ADR activity of breast cancer remains unclear. Here, we aim to investigate the imbalance of a particular long noncoding RNA, lncRNA CBR3 antisense RNA 1 (CBR3-AS1), and its role in ADR resistance.

Methods

Microarray analysis of ADR-resistant breast cancer cells was performed to identify CBR3-AS1. CCK-8 and colony formation assays were used to detect the sensitivity of breast cancer cells to ADR. Dual-luciferase reporter, RNA pulldown, IHC and western blot analyses were used to verify the relationship between the expression of CBR3-AS1, miRNA and target genes. For in vivo experiments, the effect of CBR3-AS1 on breast cancer resistance was observed in a xenograft tumor model. The role of CBR3-AS1 in influencing ADR sensitivity was verified by clinical breast cancer specimens from the TCGA, CCLE, and GDSC databases.

Results

We found that CBR3-AS1 expression was significantly increased in breast cancer tissues and was closely correlated with poor prognosis. CBR3-AS1 overexpression promoted ADR resistance in breast cancer cells in vitro and in vivo. Mechanistically, we identified that CBR3-AS1 functioned as a competitive endogenous RNA by sponging miR-25-3p. MEK4 and JNK1 of the MAPK pathway were determined to be direct downstream proteins of the CBR3-AS1/miR-25-3p axis in breast cancer cells.

Conclusions

In summary, our findings demonstrate that CBR3-AS1 plays a critical role in the chemotherapy resistance of breast cancer by mediating the miR-25-3p and MEK4/JNK1 regulatory axes. The potential of CBR3-AS1 as a targetable oncogene and therapeutic biomarker of breast cancer was identified.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01844-7.

MYC DNA Methylation in Prostate Tumor Tissue Is Associated with Gleason Score

Increasing evidence suggests a role of epigenetic mechanisms at chromosome 8q24, an important cancer genetic susceptibility region, in prostate cancer. We investigated whether MYC DNA methylation at 8q24 (six CpG sites from exon 3 to the 3′ UTR) in prostate tumor was associated with tumor aggressiveness (based on Gleason score, GS), and we incorporated RNA expression data to investigate the function. We accessed radical prostatectomy tissue for 50 Caucasian and 50 African American prostate cancer patients at the University of Maryland Medical Center, selecting an equal number of GS 6 and GS 7 cases per group. MYC DNA methylation was lower in tumor than paired normal prostate tissue for all six CpG sites (median difference: −14.74 to −0.20 percentage points), and we observed similar results for two nearby sites in The Cancer Genome Atlas (p < 0.0001). We observed significantly lower methylation for more aggressive (GS 7) than less aggressive (GS 6) tumors for three exon 3 sites (for CpG 212 (chr8:128753145), GS 6 median = 89.7%; GS 7 median = 85.8%; p-value = 9.4 × 10⁻⁴). MYC DNA methylation was not associated with MYC expression, but was inversely associated with PRNCR1 expression after multiple comparison adjustment (q-value = 0.04). Findings suggest that prostate tumor MYC exon 3 hypomethylation is associated with increased aggressiveness.

Long Noncoding RNA SNHG12 Promotes Prostate Tumor Occurrence and Progression via AKT Regulation

The small nucleolar RNA host gene 12 (SNHG12) has been reported to play an important role in the tumorigenesis and progression of PCa, but the functional underlying mechanism has not been studied clearly. We detected the expression level of SNHG12 in PCa tissues and matched adjacent normal tissues that were collected from 85 patients. Then, colony formation assays, MTT experiments, and flow cytometry were used to examine the effect of SNHG12 on proliferation, cell cycle distribution, and apoptosis of DU145 cells. Further, Transwell invasion assay was utilized to assess whether SNHG12 participates in PCa cell invasion and affects the secretion of VEGF secretion in DU145 cells. Finally, we investigated the effect of SNHG12 on tumor growth in vivo. We found that SNHG12 promoted cell proliferation and suppressed apoptosis in PCa cells, which suggests that SNHG12 is probably a novel PCa biomarker and therapy target of PCa.

Long noncoding RNA HOTAIR regulates the invasion and metastasis of prostate cancer by targeting hepaCAM

Background

The role of HOX transcript antisense RNA (HOTAIR) has been proven to be important in tumorigenesis. However, how this molecule promotes metastasis and invasion in PCa is still unclear.

Methods

The relationship between HOTAIR and hepatocellular adhesion molecule (hepaCAM) in PCa was identified by immunohistochemistry, immunofluorescence, plasmid transfection, quantitative real-time PCR and immunoblotting. The regulatory effects of HOTAIR on hepaCAM and MAPK signalling and their key roles in PCa metastasis were investigated in vitro.

Results

The expression of HOTAIR was inversely correlated with hepaCAM in the blood and tissue of PCa patients. Here, hepaCAM was identified as a novel target gene of HOTAIR and was critical for the invasiveness of PCa. HOTAIR recruited PRC2 to the hepaCAM promoter, resulting in high levels of H3K27me3 and the absence of hepaCAM with an abnormally activated MAPK pathway. Both HOTAIR depletion and EZH2 inhibition could induce hepaCAM re-expression with inhibitory MAPK signalling and decrease the invasive and metastatic capabilities of PCa cells.

Conclusions

This study demonstrates that HOTAIR promotes invasion and metastasis of PCa by decreasing the inhibitory effect of hepaCAM on MAPK signalling. Therefore, the HOTAIR/hepaCAM/MAPK axis may provide a new avenue towards therapeutic strategies and prognostic indicators for advanced prostate cancer.

Long Non-coding RNAs in Pulmonary Neuroendocrine Neoplasms

Pulmonary neuroendocrine neoplasms (NENs) are classified into low-grade neuroendocrine tumors and high-grade neuroendocrine carcinomas (NECs). There are significant differences in therapeutic strategies of the different NEN subtypes, and therefore, precise classification of pulmonary NENs is critical. However, challenges in pulmonary NEN classification include overlap of diagnostic histological features among the subtypes and reduced or negative expression of neuroendocrine markers in poorly differentiated pulmonary NECs. Recently, transcription factor insulinoma-associated protein 1 (INSM1) was identified as a sensitive marker of neuroendocrine and neuroepithelial differentiation. In this study, INSM1 expression was detected by immunohistochemistry in greater than 94% of pulmonary NENs, indicating that it is a highly sensitive marker of pulmonary NENs and is useful to detect poorly differentiated pulmonary NECs. Although there are well-established morphological and immunohistologic criteria to diagnose pulmonary NENs, there is no universal consensus regarding prognostic markers of pulmonary NENs. Studies have shown that non-small cell lung cancers express long non-coding RNAs (lncRNAs), which regulate gene expression, epithelial-to-mesenchymal transition, and carcinogenesis. We characterized expression and function of lncRNAs, including HOX transcript antisense RNA (HOTAIR), maternally expressed 3 (MEG3), and prostate cancer antigen 3 (PCA3) in pulmonary NENs, including typical carcinoid tumors, atypical carcinoid tumors, small cell lung carcinoma (SCLC/NEC), and large cell neuroendocrine carcinoma (LCNEC/NEC). In situ hybridization and real-time polymerase chain reaction studies showed higher expression (p < 0.01) of all lncRNAs in SCLC/NEC. Small interfering RNA studies indicated a role for MEG3 and PCA3 in tumor proliferation. Therefore, these lncRNAs may serve as prognostic indicators of pulmonary NEN aggressiveness and as possible therapeutic targets.

LncRNA ZEB1-AS1 Regulates Colorectal Cancer Cells by MiR-205/YAP1 Axis

Background

Recent studies demonstrated that long non-coding RNAs (lncRNAs) were involved in many biological processes. Dysregulated lncRNAs are related to many cancers, including colorectal cancer (CRC). However, the molecular mechanism of lncRNA ZEB1-AS1 in CRC is not clear.

Methods

LncRNA ZEB1-AS1, miR-205, and YAP1 expression were measured by quantitative reverse transcriptase PCR (QRT-PCR). YAP1 protein expression was measured by western blotting. Cell viability was measured by MTT assay. Cell apoptosis was detected by flow cytometry. Luciferase reporter assay was used to confirm the relationship between ZEB1-AS1, miR-205, and YAP1.

Results

LncRNA ZEB1-AS1 and YAP1 was upregulated in CRC tissues. The expression of YAP1 was positively correlated with ZEB1-AS1. Knockdown of ZEB1-AS1 inhibited cell viability and induced apoptosis in CRC cell line SW480 and HCT116 which could be reversed by overexpression of YAP1. ZEB1-AS1 targeted and regulated miR-205 which could directly bind to YAP1. Meanwhile, ZEB1-AS1 regulated the expression of YAP1 via modulating miR-205.

Conclusion

Long non-coding RNA ZEB1-AS1 silencing could inhibit cell proliferation and induce apoptosis of colorectal cancer via regulating miR-205 and YAP1.

Long noncoding RNA HOTTIP overexpression: A potential prognostic biomarker in prostate cancer

HOXA transcript at the distal tip (HOTTIP) is a long noncoding RNA (lncRNA), which is >200 nucleotides in length. HOTTIP expression has been demonstrated to play a crucial oncogenic role in cancer pathogenesis, and is said to be associated with poor human cancer prognosis. In prostate cancer, HOTTIP has been identified as an oncogene, but its clinicopathologic significance remains unclear. Array-based qRT-PCR was used to investigate lncRNA levels in 10 pairs of prostate cancer tissues and non-neoplastic parenchyma. Tissue microarray (TMA) was constructed using a total of 70 surgically resected prostatic adenocarcinoma tissues obtained from the Korea University Anam Hospital from 2009 to 2013. HOTTIP expression was determined by RNA in situ hybridization(ISH) and was correlated with clinicopathologic features. Increased HOTTIP expression was observed in all available prostate cancer tissue specimens compared with that in paired normal tissue. High HOTTIP expression was positively associated with bad clinicopathologic features, including higher pathologic T stage (p < 0.001), presence of extraprostatic extension (p < 0.001), seminal vesicle invasion (p < 0.001), perineural invasion (p < 0.001), and the tumor involvement of resection margin (p = 0.044). In particular, significantly increased HOTTIP expression was observed in specimens from patients in the high or very high-risk group, according to the 2018 National Comprehensive Cancer Network (NCCN) guidelines (p < 0.001). Also, patients with high HOTTIP expression showed poorer overall survival than those with low expression. In conclusion, we analytically validated the poor prognostic significance of HOTTIP overexpression and its association with bad clinicopathologic features, and present HOTTIP as a potential prognostic biomarker in prostate cancer.

Effect of astragalosides on long non-coding RNA expression profiles in rats with adjuvant-induced arthritis

Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology, which occurs in ~1.0% of the general population. Increasing studies have suggested that long non-coding RNAs (lncRNAs) may serve important roles in various biological processes and may be associated with the pathogenesis of different types of disease, including RA. Astragalosides (AST) has been used as a traditional Chinese medicine for the treatment of RA. However, the mechanism underlying its therapeutic effect has remained unclear to date. Thus, there is an urgent need to elucidate the possible mechanism of AST in the treatment of RA from the perspective of lncRNAs. In the present study, the lncRNAs and mRNAs of a vehicle group, animal model group and AST treatment (control) group were determined by Arraystar Rat lncRNA/mRNA microarray. The differentially expressed genes with a fold change >1.5 and P<0.05 were selected and analyzed. Gene Ontology (GO) and pathway analysis was performed using the Database for Annotation, Visualization and Integration Discovery, and the coding-non-coding gene co-expression network was drawn based on the correlation analysis between the differentially expressed lncRNAs and mRNAs. Based on node degree and the correlation between bioinformatics analysis and RA, the critical differentially expressed lncRNAs were selected, analyzed and verified by reverse transcription-quantitative PCR (RT-qPCR) analysis. The results showed that, following AST treatment, up to 75 lncRNAs and 247 mRNAs were found to be differentially expressed among the three groups. GO and pathway analysis manifested that 135 GO terms and 17 pathways were enriched by differentially expressed genes. Four lncRNAs (MRAK012530, MRAK132628, MRAK003448 and XR_006457) were selected as the critical lncRNAs and their trend in expression showed consistency between the RT-qPCR and microarray data. In conclusion, AST had a regulatory effect on differentially expressed lncRNAs during the development of RA, and four lncRNAs could be selected as critical therapeutic targets of AST.

A novel AR translational regulator lncRNA LBCS inhibits castration resistance of prostate cancer

Background

Progression to a castration resistance state is the main cause of deaths in prostate cancer (PCa) patients. Androgen Receptor (AR) signaling plays the central role in progression of Castration Resistant Prostate Cancer (CRPC), therefore understanding the mechanisms of AR activation in the milieu of low androgen is critical to discover novel approach to treat CRPC.

Methods

Firstly, we explore the CRPC associated lncRNAs by transcriptome microarray. The expression and clinical features of lnc-LBCS are analyzed in three independent large-scale cohorts. The functional role and mechanism of lnc-LBCS are further investigated by gain and loss of function assays in vitro.

Results

The expression of Lnc-LBCS was lower in CRPC cells lines and tissues. LBCS downregulation was correlated with higher Gleason Score, T stage and poor prognosis of PCa patients. LBCS overexpression decreases, whereas LBCS knockdown increases, the traits of castration resistance in prostate cancer cells under androgen ablated or AR blocked condition. Moreover, knockdown of LBCS was sufficient to activate AR signaling in the absence of androgen by elevating the translation of AR protein. Mechanistically, LBCS interacted directly with hnRNPK to suppress AR translation efficiency by forming complex with hnRNPK and AR mRNA.

Conclusions

Lnc-LBCS functions as a novel AR translational regulator that suppresses castration resistance of prostate cancer by interacting with hnRNPK. This sheds a new insight into the regulation of CRPC by lncRNA mediated AR activation and LBCS-hnRNPK-AR axis provides a promising approach to the treatment of CRPC.

Electronic supplementary material

The online version of this article (10.1186/s12943-019-1037-8) contains supplementary material, which is available to authorized users.

lncRNAs as potential molecular biomarkers in the clinicopathology and prognosis of cholangiocarcinoma: a systematic review and meta-analysis

Background

Cholangiocarcinoma (CCA) is the second most common fatal primary hepatobiliary malignant carcinoma, characterized by early invasion and extremely poor outcomes. It is therefore necessary to identify a novel biomarker to better diagnose CAA and predict its prognosis. Recently, emerging evidence has revealed that some lncRNAs play an important role in the tumorigenesis and progression of CAA. In order to support this search for novel diagnostic and prognostic biomarkers for CAA, we conducted a meta-analysis to analyze the published association between lncRNA expression and its clinical value in CAA.

Methods

Eligible studies were pooled and analyzed according to our inclusion and exclusion criteria after a comprehensive literature search. Stata 14.0 software was used to analyze the data from relevant studies and to construct a forest plot. Different effect sizes were selected for the meta-analysis.

Results

In total, 24 publications were included in this meta-analysis. After review of their full-text, 16 articles studied the association between lncRNAs and clinicopathological characteristics, 2 discussing diagnosis and 16 discussing prognosis. Our results showed that overexpression of CCAT1 was significantly correlated with tumor stage (I + II vs III + IV) (OR, 4.99; 95% CI 2.77–8.99; P<0.001) and lymph node metastasis in CCA (OR, 4.75; 95% CI 2.65–8.52; P<0.001). Furthermore, elevated CCAT lncRNA family expression predicted a shorter overall survival (HR, 2.09; 95% CI 1.17–3.00; P<0.001), especially CCAT2. Upregulation of CCAT2 was also obviously associated with tumor stage in CCA (OR, 5.29; 95% CI 2.64–10.58; P=0.001).

Conclusion

This is the first meta-analysis to assess the relationship between expression of lncRNAs and the clinical values of patients with CCA. lncRNAs can function as potential molecular biomarkers of the clinicopathology and prognosis of CCA.

Hypoxia-induced LncRNA PCGEM1 promotes invasion and metastasis of gastric cancer through regulating SNAI1

PURPOSE

Hypoxia is an indispensable factor in the progression of metastasis. Hypoxia inducible factor-1α (HIF-1α), the core element in generating the hypoxia response, induces invasion and metastasis by promoting epithelial-mesenchymal transition (EMT). This study explored the underlying mechanism of hypoxia associated with the invasion and metastasis of gastric cancer (GC).

METHODS

Six methods were employed to assess the function of the long noncoding RNA (lncRNA) prostate cancer gene expression marker 1 (PCGEM1) including gene silencing, RT-PCR, the separation of nuclear and cytoplasmic fractions, scrape motility assay, transwell migration assay, and Western-blot.

RESULTS

LncRNA PCGEM1 was overexpressed in GC cells and tissues, and was induced by hypoxia in GC cells. Additional experiments confirmed that the knockdown of PCGEM1 significantly repressed the invasion and metastasis of GC cells. SNAI1, a key transcription factor of EMT, was regulated by PCGEM1. Overexpression of SNAI1 rescued the inhibition of PCGEM1-knockdown during the invasion and metastasis of GC cells. In addition, PCGEM1 and SNAI1 jointly affected the biomarkers of EMT.

CONCLUSION

Our findings indicated that PCGEM1 is a hypoxia-responsive lncRNA, and contributes to the invasion and metastasis of GC. The potential mechanism is attributed to the regulation of EMT by PCGEM1 and its influence on the expression of SNAI1.

The emerging roles of long non-coding RNA in gallbladder cancer tumorigenesis

Accumulating evidence suggests that long non-coding RNAs (lncRNAs) have important regulatory functions in gallbladder cancer (GBC) tumorigenesis and can serve as potential novel markers and/or targets for GBC. In this review, we critically discuss the emerging alteration of lncRNAs in GBC, the lncRNAs induced epigenetic regulation, the interaction of lncRNAs with microRNAs and lncRNAs effects on tumor-related signaling pathways. Additionally, contributions of lncRNAs in epithelial-mesenchymal transition process and energy metabolism reprogramming in GBC are also addressed. This may pave new ways towards the determination of GBC pathogenesis and lead to the development of new preventive and therapeutic strategies for GBC.

The Significance of Liquid Biopsy in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal types of cancer. The 5-year survival rate for PDAC remains low because it is always diagnosed at an advanced stage and it is resistant to therapy. A biomarker, which could detect asymptomatic premalignant or early malignant tumors and predict the response to treatment, will benefit patients with PDAC. However, traditional biopsy has its limitations. There is an urgent need for a tumor biomarker that could easily and repeatedly sample and monitor, in real time, the progress of tumor development. Liquid biopsy could be a tool to assess potential biomarkers. In this review, we focused on the latest discoveries and advancements of liquid biopsy technology in pancreatic cancer research and demonstrated how this technology is being used in clinical applications.

Long non-coding RNA NAP1L6 promotes tumor progression and predicts poor prognosis in prostate cancer by targeting Inhibin-β A

Background/purpose

Long non-coding RNAs (lncRNAs) have emerged as key molecules in initiation and progression of prostate cancer (PCa). In this study, we aimed to explore the role of lncRNA NAP1L6 in the development and progression of PCa.

Materials and methods

We identified that lncRNA NAP1L6 was over-expressed both in PCa tissues and cell lines by gene expression array profiling. The expression level of NAP1L6 in 75 PCa tissues and adjacent tissues was detected by RT-PCR. Next, the correlations between NAP1L6 expression and clinical features of patients with PCa were analyzed by paired t-test or chi-squared test, and its association with patient prognosis was assessed by the Kaplan-Meier method. The effects of NAP1L6 on PC-3 and 22RV1 cells were evaluated by Cell Counting Kit-8 (CCK-8), migration, invasion, and colony formation assays. Further analysis of the results of the microarray was performed to find downstream gene of NAP1L6. Cell function experiments were performed in order to explore the relationship between NAP1L6 and Inhibin-β A (INHBA) and the specific mechanism by which INHBA affects the development of PCa.

Results

Using microarray analysis, we identified 412 lncRNAs and 1245 mRNAs to be significantly differentially expressed in three PCa samples when compared with adjacent non-tumor tissues (ANTT) (fold-change ≥2.0 or ≤0.5, P<0.05, false discovery rate (FDR) <0.05). NAP1L6 expression was upregulated in PCa tissues and cell lines (both P<0.05) compared with ANTT. Besides, high expression level of NAP1L6 promotes PCa cell proliferation, migration, and invasion (all P<0.05), and is significantly associated with larger tumor diameter, distant metastasis, and shorter survival time (all P<0.05). We found that NAP1L6 promoted the expression of INHBA (P<0.05), and knockdown of NAP1L6 led to the reduction of PCa cell migration, invasion, and proliferation by regulating the expression of INHBA (all P<0.05).

Conclusion

lncRNA NR6A1 might play an oncogenic role in PCa initiation and progression by regulating the expression of INHBA, and might act as a novel prognostic biomarker for PCa treatment.

Small nucleolar RNA host gene 1: A new biomarker and therapeutic target for cancers

OBJECTIVES

Long non-coding RNAs (lncRNAs), a group of transcripts with length greater than 200 nucleotides, have been involved in multiple pathophysiological processes of the human body, especially in tumorigenesis and progression of cancers. The aberrant expression of lncRNAs processes crucial functions involved in proliferation, apoptosis and metastatic capacity of cancers. Recent studies have revealed that small nucleolar RNA host gene 1 (SNHG1), a long non-coding RNA transcribed from UHG, was located in chromosome 11. Aberrant expression of SNHG1 has been demonstrated to be associated with various sites of cancers such as glioma, esophageal cancer, gastric cancer and many others, and its deregulation could be related to survival and prognosis of cancer patients. Pertinent to clinical practice, SNHG1 might act as a prognostic biomarker for tumors and might even serve as potential target for therapy. In this review, we summarized current researches concerning the role of SNHG1 in tumor progression and discussed its mechanisms involved.

MATERIALS AND METHODS

In this review, we summarized and figured out recent studies concerning the expression and biological mechanisms of SNHG1in tumor development. The related studies were obtained through a systematic search of PubMed, Embase and Cochrane Library.

RESULTS

SNHG1 was a valuable cancer-related lncRNA that the expression level was up-regulation in a variety of malignancies, including glioma, esophageal cancer, lung cancer, gastric cancer, hepatocellular carcinoma, colorectal carcinoma, prostate cancer, cervical cancer, osteosarcoma, neuroblastoma, nasopharyngeal carcinoma. The aberrant expressions of SNHG1 have shown to contribute to proliferation, migration, and invasion of cancer cells.

CONCLUSIONS

SNHG1 represents promising novel biomarkers for various cancer types and have a great potential to be effectively used in clinical practice in the near future.

Enhanced expression of lncRNA TP73-AS1 predicts adverse phenotypes for cholangiocarcinoma and exerts oncogenic properties in vitro and in vivo

Cholangiocarcinoma (CCA) is one of the most aggressive malignancies with increasing incidence worldwide. Various evidence documents that abnormally expressed long non-coding RNAs (lncRNAs) play important roles in tumorigenesis and progression. TP73-AS1 is a novel cancer-related lncRNA that contributes to the development of several malignancies. However, its clinical value and potential effects on CCA remains unknown. RT-qPCR was used to measure the expression levels of TP73-AS1 in CCA tissues and paired non-tumor tissues and the association between TP73-AS1 expression and clinicopathological characteristics was analyzed. In addition, the functional roles of TP73-AS1 in CCA were detected both in vitro and in vivo. The results illustrated that TP73-AS1 transcription is enhanced in both CCA tissue samples and cell lines, and this upregulation is closely associated with larger tumor size (p=0.008) and advanced TNM stage (p=0.026) in patients with CCA. For the part of functional assays, silencing of TP73-AS1 could attenuate CCA cell growth both in vitro and in vivo. Additionally, silencing of TP73-AS1 facilitates apoptosis via activating caspase-3 and caspase-9. Importantly, TP73-AS1 expression did not affect HIBEC cell growth and apoptosis. Moreover, TP73-AS1 could also facilitate migration and invasion potential of CCA cells. Collectively, these findings may help to develop a potential therapeutic target for the patients with CCA.

Long non-coding RNA HOTTIP is upregulated in renal cell carcinoma and regulates cell growth and apoptosis by epigenetically silencing of LATS2

Renal cell carcinoma (RCC) is one of the most aggressive malignancies with increasing incidence worldwide and is characterized by dismal prognosis owing to a lack of early detection and prognostic biomarkers for this fatal disease. Accumulating studies demonstrated that abnormally expressed long non-coding RNAs (lncRNAs) are involved in tumorigenesis and progression. Specifically, HOTTIP is upregulated and exerts oncogenic properties in some cancers. However, its clinical significance, biological functions and molecular mechanisms in RCC have not been studied. In the current study, RT-qPCR was performed to quantify the relative expression of HOTTIP in RCC tissues and cells. Additionally, we explored its clinical value using Fisher's exact test. Moreover, cell growth and apoptosis altered by HOTTIP was evaluated in vitro and in vivo. Mechanistically, RNA immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP) analysis was used to determine its molecular mechanism in cell growth and apoptosis. As a result, upregulated HOTTIP is closely associated with unfavorable phenotypes in RCC patients. The mechanistic investigations showed that HOTTIP could bind to enhancer of zeste homolog 2 (EZH2) and lysine specific demethylase 1 (LSD1), thereby repressing LATS2 expression. Collectively, our study illustrates how HOTTIP plays an oncogenic role in RCC and may offer a potential therapeutic target for treating this fatal disease.

PANDAR: a pivotal cancer-related long non-coding RNA in human cancers

Long non-coding RNAs (lncRNAs), non-protein-coding RNAs that are more than 200 nucleotides in length, have been demonstrated to play a vital role in the pathophysiology of human diseases, particularly in tumorigenesis and progression of cancers. Dysregulation of lncRNAs, which serve as either oncogenes or tumor suppressor genes, is involved in diverse cellular processes, such as proliferation, dedifferentiation, migration, invasion and anti-apoptosis. Promoter of CDKN1A antisense DNA damage-activated RNA (PANDAR), which was recently found to manifest aberrant expression in various malignancies including non-small cell lung cancer, hepatocellular carcinoma, colorectal cancer and gastric cancer, is a novel cancer-related lncRNA. Deregulation of PANDAR contributes to tumorigenesis and progression of cancers, suggesting that PANDAR is likely to represent a viable biomarker and therapeutic target for human cancers. In this review, we summarize current evidence regarding the biological functions and mechanisms of PANDAR during tumor development.

LncRNA HULC mediates radioresistance via autophagy in prostate cancer cells

Prostate cancer (PCa) is the second leading cause of cancer death in men. Irradiation is one of the available options for treatment of PCa, however, approximately 10-45% of PCa are resistant to irradiation. We aimed to explore the role of long non-coding RNA highly upregulated in liver cancer (HULC) in the sensitivity of PCa cells to irradiation. Survival rate, cell apoptosis, cycle, expressions of related proteins, and caspase-3 activity were assessed to explore the effects of HULC on sensitivity of PCa cells to irradiation. Expression of HULC in DU-145, PC3, LNCaP, and RWPE-1 cells was determined and the influence of HULC on DU-145 cells was explored. Then, PC3 cells aberrantly expressing HULC were implanted into NOD-SCID mice for tumor xenograft study. Changes of autophagy after aberrant expression of HULC in vivo and in vitro were tested. Furthermore, the interacted protein of HULC and involved signaling pathway were investigated. In PC3 and LNCaP cells under irradiation, survival rate and cell cycle were decreased and apoptosis was increased by HULC knockdown. HULC knockdown arrested PC3 cells at G0/G1 phase. DU-145 was sensitive to irradiation, and resistance to irradiation of DU-145 cells was enhanced by HULC overexpression. Moreover, HULC knockdown enhanced the sensitivity of PC3 xenografts to irradiation. HULC knockdown promoted autophagy through interaction with Beclin-1 and inhibition of mTOR, resulting in increased apoptosis. HULC knockdown improved sensitivity of PCa cells to irradiation both in vivo and in vitro. HULC suppressed Beclin-1 phosphorylation, thereby reduced autophagy, involving the mTOR pathway.

The use of long non-coding RNAs as prognostic biomarkers and therapeutic targets in prostate cancer

Prostate cancer is the most common cancer in men and the second leading cause of cancer-related deaths. The most used biomarker to detect prostate cancer is Prostate Specific Antigen (PSA), whose levels are measured in serum. However, it has been recently established that molecular markers of cancer should not be based solely on genes and proteins but should also reflect other genomic traits; long non-coding RNAs (lncRNAs) serve this purpose. lncRNAs are transcripts of >200 bases that do not encode proteins and that have been shown to display abnormal expression profiles in different types of cancer. Experimental studies have highlighted lncRNAs as potential biomarkers for prognoses and treatments in patients with different types of cancer, including prostate cancer, where the PCA3 lncRNA is currently used as a diagnostic tool and management strategy. With the development of genomic technologies, particularly next-generation sequencing (NGS), several other lncRNAs have been linked to prostate cancer and are currently under validation for their medical use. In this review, we will discuss different strategies for the discovery of novel lncRNAs that can be evaluated as prognostic biomarkers, the clinical impact of these lncRNAs and how lncRNAs can be used as potential therapeutic targets.

Non-coding RNAs: long non-coding RNAs and microRNAs in endocrine-related cancers

The human genome is 'pervasively transcribed' leading to a complex array of non-coding RNAs (ncRNAs) that far outnumber coding mRNAs. ncRNAs have regulatory roles in transcription and post-transcriptional processes as well numerous cellular functions that remain to be fully described. Best characterized of the 'expanding universe' of ncRNAs are the ~22 nucleotide microRNAs (miRNAs) that base-pair to target mRNA's 3' untranslated region within the RNA-induced silencing complex (RISC) and block translation and may stimulate mRNA transcript degradation. Long non-coding RNAs (lncRNAs) are classified as >200 nucleotides in length, but range up to several kb and are heterogeneous in genomic origin and function. lncRNAs fold into structures that interact with DNA, RNA and proteins to regulate chromatin dynamics, protein complex assembly, transcription, telomere biology and splicing. Some lncRNAs act as sponges for miRNAs and decoys for proteins. Nuclear-encoded lncRNAs can be taken up by mitochondria and lncRNAs are transcribed from mtDNA. Both miRNAs and lncRNAs are dysregulated in endocrine cancers. This review provides an overview on the current understanding of the regulation and function of selected lncRNAs and miRNAs, and their interaction, in endocrine-related cancers: breast, prostate, endometrial and thyroid.

LncRNA CBR3-AS1 predicts unfavorable prognosis and promotes tumorigenesis in osteosarcoma

LncRNA CBR3-AS1 has been suggested to promote malignancy in several types of human cancers, but the clinical significance and biological function of lncRNA CBR3-AS1 in osteosarcoma is still unknown. The purpose of our study is to explore the clinical significance of lncRNA CBR3-AS1 in osteosarcoma patients and the biological function in osteosarcoma cells. In our results, we found lncRNA CBR3-AS1 was highly-expressed in osteosarcoma tissues and cell lines, and associated with Enneking stage, distant metastasis and histological grade. Survival analysis indicated that the high-expression of lncRNA CBR3-AS1 was an independent poor prognostic factor for osteosarcoma patients. Loss-of-function studies showed knockdown of lncRNA CBR3-AS1 suppressed osteosarcoma cells proliferation, migration and invasion, and promotes cells apoptosis, but had no effect on cell-cycle distribution. There was no association between lncRNA CBR3-AS1 and CBR3 expression in osteosarcoma tissues, and knockdown of lncRNA CBR3-AS1 had no effect on CBR3 mRNA and protein expression osteosarcoma cells. In conclusion, lncRNA CBR3-AS1 serves an oncogenic role to regulate osteosarcoma cells proliferation, migration, invasion and apoptosis, and is an independent poor prognostic factor for osteosarcoma patients.

Long non-coding RNA urothelial carcinoma associated 1 (UCA1) mediates radiation response in prostate cancer

Radioresistance remains a significant obstacle in the treatment of Prostate Cancer (PCa). To simulate the clinical scenario of irradiation resistance (IRR), we created DU145-IRR PCa cell lines by treatment with 2 Gy daily IR for 59 fractions. DU145-IRR cells acquired an aggressive phenotype as evidenced by increased clonogenic survival, tumorigenic potential and invasiveness. We performed transcriptome profiling to discover dysregulated genes in DU145-IRR cells and identified the long non-coding RNA (lncRNA), Urothelial carcinoma-associated 1 (UCA1). We first investigated the role of UCA1 in radiation response and found that UCA1 abundance was significantly higher in DU145-IRR cells compared to control cells. UCA1 siRNA-knockdown reversed the aggressive phenotype and significantly increased sensitivity to IR. UCA1 depletion inhibited growth, induced cell cycle arrest at the G2/M transition and decreased activation of the pro-survival Akt pathway. We then studied the clinical significance of UCA1 expression in two independent cohorts of PCa patients: MSKCC (130 patients) and CPC-GENE (209 patients). UCA1 over-expression was associated with decreased 5-year disease-free survival in MSKCC patients (HR = 2.9; p = 0.007) and a trend toward lower biochemical recurrence-free survival in CPC-GENE patients (HR = 2.7; p = 0.05). We showed for the first time that UCA1 depletion induces radiosensitivity, decreases proliferative capacity and disrupts cell cycle progression, which may occur through altered Akt signaling and induced cell cycle arrest at the G2/M transition. Our results indicate that UCA1 might have prognostic value in PCa and be a potential therapeutic target.

Overexpressed long noncoding RNA Sox2ot predicts poor prognosis for cholangiocarcinoma and promotes cell proliferation and invasion

SOX2 overlapping transcript (Sox2ot), a long noncoding RNA (lncRNA), was initially found a close concomitant expression pattern of SOX2 gene. Multiple studies have demonstrated that the relatively upregulated Sox2ot could be observed in different types of cancer tissues and effectively promotes cell proliferation, invasion, and tumorigenesis in vitro. In the present study, we aimed to detect the crucial prognostic role of Sox2ot in cholangiocarcinoma (CCA) patients' clinicopathologic features and evaluated the correlation between Sox2ot expression and CCA patients overall survival. 58 CCA patients who underwent surgical treatment were recruited for the investigation. Sox2ot expression levels estimated by the quantitative real-time PCR (qRT-PCR) showed that both clinical tissues and cell lines possessed the overexpressed states and the upregulation of Sox2ot significantly associated with lymph node invasion (p=0.0308), TNM stage (p=0.0072) and postoperative recurrence (p=0.0019). The Kaplan-Meier curve showed a strong association between Sox2ot and overall survival (OS) and multivariate analysis confirmed this finding. Furthermore, the proliferation, migration and invasion assays were carried out with RBE and QBC939 cell lines and the knockdown of Sox2ot in all experiments could remarkably decrease malignant biological behaviors. Taken together, lncRNA Sox2ot indicates an unfavorable prognostic biomarker and potential therapeutics target for CCA patients.

ZEB1-AS1: A crucial cancer-related long non-coding RNA

Long non-coding RNAs (lncRNAs) recently emerge as a novel class of non-coding RNAs (ncRNAs) with larger than 200 nucleotides in length. Due to lack an obvious open reading frame, lncRNAs have no or limited protein-coding potential. To date, accumulating evidence indicates the vital regulatory function of lncRNAs in pathological processes of human diseases, especially in carcinogenesis and development. Deregulation of lncRNAs not only alters cellular biological behavior, such as proliferation, migration and invasion, but also represents the poor clinical outcomes. Zinc finger E-box binding homeobox 1 antisense 1 (ZEB1-AS1), an outstanding cancer-related lncRNA, is identified as an oncogenic regulator in diverse malignancies. Dysregulation of ZEB1-AS1 has been demonstrated to exhibit a pivotal role in tumorigenesis and progression, suggesting its potential clinical value as a promising biomarker or therapeutic target for cancers. In this review, we make a summary on the current findings regarding the biological functions, underlying mechanisms and clinical significance of ZEB1-AS1 in cancer progression.

Long noncoding RNA identification in lymphoma

It has been found that long noncoding RNA (lncRNA) are abnormally expressed in lymphoma and play an important role in its pathogenesis. Through the detection and analysis of lncRNA, it was found that lncRNA could be used as an excellent biomarker for the diagnosis and prognosis of cancer. In lymphoma, abnormal lncRNA expression is associated with the patient's clinical characteristics, it can be used to determine the prognosis of the patient and serve as a therapeutic target in the disease.

An increased expression of long non-coding RNA PANDAR promotes cell proliferation and inhibits cell apoptosis in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies worldwide. Emerging evidence indicates that aberrantly expressed long non-coding RNAs (lncRNAs) act as imperative roles in tumorigenesis and progression. PANDAR (promoter of CDKN1A antisense DNA damage activated RNA) is a novel lncRNA that contributes to the development of various cancers. However, its clinical significance and potential effects on PDAC remains unknown. In the present study, qRT-PCR was performed to explore the expression levels of PANDAR in PDAC tissues and corresponding non-tumor tissues, the correlation between PANDAR expression and clinicopathological characteristics was also analyzed. The functional roles of lncRNA PANDAR in PDAC cells were evaluated both in vitro and in vivo. The results indicated that PANDAR was aberrantly overexpressed in PDAC tissues and cell lines, and this overexpression was closely associated with tumor stage and vascular invasion in PDAC patients. Besides, silencing of PANDAR exerted tumor suppressive effect via reducing cell proliferation, colony-forming ability, inducing cell cycle G0/G1 arrest and apoptosis in PANC1 and Capan-2 cells. Further in vivo study confirmed the oncogenesis role of PANDAR in PDAC cells. Overall, our findings may help to develop a potential therapeutic target for the patients with PDAC.

Knockdown of long non-coding RNA MEG3 protects H9c2 cells from hypoxia-induced injury by targeting microRNA-183

Acute myocardial infarction (AMI) occurs when blood supply to the heart is diminished (ischemia) for long time, and ischemia is primarily caused due to hypoxia. This study evaluated the effects of long non-coding RNA maternally expressed gene 3 (MEG3) on hypoxic rat cardiomyocyte-drived H9c2 cells. Hypoxic injury was confirmed by alterations of cell viability, migration, invasion, apoptosis, and hypoxia-inducible factor 1α (HIF-1α) expression. MEG3 level in hypoxic cells and effects of its knockdown on hypoxic cells were assessed. The interactions between MEG3 and miR-183 as well as miR-183 and p27 were investigated. In addition, the effects of aberrantly expressed MEG3, miR-183, and p27 on hypoxic cells along with the activation of PI3K/AKT/FOXO3a signaling pathway were all assessed. Results showed that hypoxia induced decreases of cell viability, migration and invasion, and increases of apoptosis and expressions of HIF-1α and MEG3. Knockdown of MEG3 decreased hypoxia-induced injury in H9c2 cells. Knockdown of MEG3 also increased miR-183 expression, which was identified as a target of MEG3. The effects of MEG3 knockdown on the hypoxic cells were reversed by miR-183 silence. p27 was identified as a target gene of miR-183, and its expression negatively regulated by miR-183. The mechanistic studies revealed that knockdown of p27 decreased hypoxia-induced H9c2 cell injury by activating PI3K/AKT/FOXO3a signal pathways. These findings suggest that knockdown of MEG3 alleviates hypoxia-induced H9c2 cell injury by miR-183-mediated suppression of p27 through activation of PI3K/AKT/FOXO3a signaling pathway.

LncRNA-ATB: An indispensable cancer-related long noncoding RNA

OBJECTIVES

Long non-coding RNAs (lncRNAs) are a group of non-protein-coding RNAs that are greater than 200 nucleotides in length. Increasing evidence indicates that lncRNAs, which may serve as either oncogenes or tumour suppressor genes, play a vital role in the pathophysiology of human diseases, especially in tumourigenesis and progression. Deregulation of lncRNAs impacts different cellular processes, such as proliferation, dedifferentiation, migration, invasion and anti-apoptosis. The aim of this review was to explore the molecular mechanism and clinical significance of long non-coding RNA-activated by transforming growth factor β (lncRNA-ATB) in various types of cancers.

MATERIALS AND METHODS

In this review, we summarize and analyze current studies concerning the biological functions and mechanisms of lncRNA-ATB in tumour development. The related studies were obtained through a systematic search of Pubmed, Web of Science, Embase and Cochrane Library.

RESULTS

Long non-coding RNAs-ATB is a novel cancer-related lncRNA that was recently found to exhibit aberrant expression in a variety of malignancies, including hepatocellular carcinoma, colorectal cancer, gastric cancer, and lung cancer. Dysregulation of lncRNA-ATB has been shown to contribute to proliferation, migration and invasion of cancer cells. Long non-coding RNAs-ATB promotes tumourigenesis and progression mainly through competitively binding miRNAs to induce epithelial-mesenchymal transition (EMT).

CONCLUSIONS

Long non-coding RNAs-ATB likely represents a feasible cancer biomarker or therapeutic target.

Curcumin suppresses proliferation and in vitro invasion of human prostate cancer stem cells by ceRNA effect of miR-145 and lncRNA-ROR

Many studies have demonstrated that curcumin can effectively inhibit the proliferation, invasion, and tumorigenesis of prostate cancer cells in vitro and in vivo. In this study, CD44⁺/CD133⁺ human prostate cancer stem cells (HuPCaSCs) were isolated from the prostate cancer cell lines Du145 and 22RV1. Curcumin treatment of these cells resulted in the inhibition of in vitro proliferation and invasion, and cell cycle arrest. The expression levels of cell cycle proteins (Ccnd1 and Cdk4) and stem cell markers (Oct4, CD44, and CD133) were decreased in curcumin-treated HuPCaSCs. Microarray analysis and northern blotting assays indicated that miR-145 was overexpressed in curcumin-treated HuPCaSCs. Insights of the mechanism of competitive endogenous RNAs (ceRNAs) were gained from bioinformatic analysis, bioinformatics analysis and luciferase activity assays showed that the lncRNA-ROR and Oct4 mRNA both contain miR-145 binding sites, and Oct4 and lncRNA-ROR directly compete for microRNA binding. Curcumin induced high miR-145 expression and inhibited the expression of lncRNA-ROR. The tumorigenicity of curcumin- treated HuPCaSCs in nude mice was significantly reduced. In summary, reducing the expression of endogenous lncRNA-ROR could effectively increase the available concentration of miR-145 in HuPCaSCs, where miR-145 prevents cell proliferation by decreasing Oct4 expression. In particular, we hypothesized that lncRNA-ROR may act as a ceRNA, effectively becoming a sink for miR-145, thereby activating the derepression of core transcription factors Oct4. Thus, curcumin suppresses the proliferation, in vitro invasion, and tumorigenicity of HuPCaSCs through ceRNA effect of miR-145 and lncRNA-ROR caused.

Long noncoding RNA PCAT1 regulates extrahepatic cholangiocarcinoma progression via the Wnt/β-catenin-signaling pathway

Extrahepatic cholangiocarcinoma (ECC) is a deadly disease that often responds poorly to conventional chemotherapy or radiotherapy. Long noncoding RNAs (lncRNAs) play important roles in human cancers, including ECC, and recent studies indicated that the lncRNA prostate cancer-associated transcript 1 (non-protein coding) (PCAT1) is involved in multiple cancers. However, the role of PCAT1 in ECC is unclear. Previously, we showed that PCAT1 is up-regulated in both ECC tissue samples and cell lines. Here, we showed that downregulation of PCAT1 following transfection with silencing RNA reduced ECC cell growth and increased cell apoptosis. Additionally, PCAT1 suppression inhibited ECC cell migration and invasion as determined by transwell assay. Furthermore, we determined that PCAT1 is a competing endogenous for microRNA (miR)-122, with bioinformatics analysis and luciferase-reporter assay results demonstrating that PCAT1 regulated WNT1 expression via miR-122. Moreover, PCAT1 downregulation increased levels of glycogen synthase kinase 3β and significantly decreased β-catenin levels in whole cell lysates and nuclear fractions, indicating that PCAT1 silencing inhibited the Wnt/β-catenin-signaling pathway. We also observed that exogenous expression of WNT1 reversed PCAT1-silencing-induced inhibition of ECC cell growth inhibition. These results indicated that PCAT1 silencing inhibited ECC progression by reducing Wnt/β-catenin signaling through miR-122 repression and WNT1 expression. Our findings revealed an important role of PCAT1 in ECC and suggested that PCAT1 might be a potential ECC-related therapeutic target.

Genomic Insight into the Role of lncRNA in Cancer Susceptibility

With the development of advanced genomic methods, a large amount of long non-coding RNAs (lncRNAs) has been found to be important for cancer initiation and progression. Given that most of the genome-wide association study (GWAS)-identified cancer risk SNPs are located in the noncoding region, the expression and function of lncRNAs are more likely to be affected by the SNPs. The SNPs may affect the expression of lncRNAs directly through disrupting the binding of transcription factors or indirectly by affecting the expression of regulatory factors. Moreover, SNPs may disrupt the interaction between lncRNAs and other RNAs or proteins. Unveiling the relationship of lncRNA, protein-coding genes, transcription factors and miRNAs from the angle of genomics will improve the accuracy of disease prediction and help find new therapeutic targets.

Upregulated long noncoding RNA PANDAR predicts an unfavorable prognosis and promotes tumorigenesis in cholangiocarcinoma

Cholangiocarcinoma (CCA) is one of the most malignant human cancers with increasing incidence worldwide. LncRNAs have emerged as gene regulators and prognostic biomarkers in a variety of neoplasms. PANDAR, a novel cancer-related lncRNA, has been reported to be upregulated in diverse human carcinomas. In this study, we aimed to investigate the clinical significance of lncRNA PANDAR in CCA and explore its functional roles in CCA cells including cell proliferation, apoptosis, migration, invasion and epithelial-to-mesenchymal transition (EMT). The results showed that PANDAR was significantly upregulated in CCA tissue specimens and cell lines, and its high expression was closely associated with lymph node invasion (P=0.004), TNM stage (P=0.034) and postoperative relapse (P=0.006) in patients with CCA. Thus, overexpression of PANDAR could serve as an independent prognostic biomarker of CCA. Furthermore, silencing of PANDAR followed by siRNA significantly inhibited cell proliferation and increased apoptosis in CCA cells. In addition, suppression of PANDAR impaired migration and invasion capacity in vitro partly by affecting EMT. Overall, our findings showed that lncRNA PANDAR serves as a novel prognostic biomarker and therapeutic target for CCA.

Overexpression of long noncoding RNA H19 indicates a poor prognosis for cholangiocarcinoma and promotes cell migration and invasion by affecting epithelial-mesenchymal transition

Cholangiocarcinoma (CCA) is a deadly disease that poorly responds to chemotherapy and radiotherapy and whose incidence has increased worldwide. Furthermore, long noncoding RNAs (lncRNAs) play important roles in multiple biological processes, including tumorigenesis. Specifically, H19, the first discovered lncRNA, has been reported to be overexpressed in diverse human carcinomas, but the overall biological role and clinical significance of H19 in CCA remains unknown. In the present study, expression levels of H19 were investigated in CCA tissues and cell lines and were correlated with clinicopathological features. Moreover, we explored the functional roles of H19 depletion in QBC939 and RBE cells, including cell proliferation, apoptosis, migration, invasion and epithelial-to-mesenchymal transition (EMT). The results indicated that H19 was upregulated in CCA tissue samples and cell lines, and this upregulation was associated with tumor size, TNM stage, postoperative recurrence and overall survival in 56 patients with CCA. Moreover, knockdown of H19 followed by RNA silencing restrained cell proliferation and promoted apoptosis. In addition, H19 suppression impaired migration and invasion potential by reversing EMT. Overall, our findings may help to develop diagnostic biomarkers and therapeutics that target H19 for the treatment of CCA.

Long Noncoding RNA SChLAP1 Accelerates the Proliferation and Metastasis of Prostate Cancer via Targeting miR-198 and Promoting the MAPK1 Pathway

Prostate cancer has become the most commonly diagnosed and the second leading cause of cancer-related deaths in males. The long noncoding RNA second chromosome locus associated with prostate-1 (SChLAP1) has been found to be overexpressed in a subset of prostate cancer. However, the significance and mechanism of SChLAP1 in prostate cancer are not well known. In this study, we explored the role of SChLAP1 in prostate cancer tissues, cell lines, and mouse models. The effect of SChLAP1 on miR-198 and MAPK1 was specifically examined. We found that SChLAP1 expression was significantly increased in prostate cancer cells and tissues. Knockdown of SChLAP1 promoted apoptosis and inhibited cell proliferation and invasion in vitro and in vivo. In addition, a potential bonding site between miR-198 and SChLAP1 was predicted, and a low expression of miR-198 was found in prostate cancer tissues and cells. Knockdown of SChLAP1 significantly increased the expression of miR-198, and SChLAP1 overexpression markedly decreased it, indicating that SChLAP1 acted as a negative regulator in the expression of miR-198. Furthermore, our results showed that SChLAP1 interacted with miR-198 and subsequently modulated the MAPK1 signaling pathway in prostate cancer. In conclusion, our study has identified a novel pathway through which SChLAP1 exerts its oncogenic role in prostate cancer at the level of miRNAs and provided a molecular basis for potential applications of SChLAP1 in the prognosis and treatment of prostate cancer.

Long noncoding RNA LINC01296 is associated with poor prognosis in prostate cancer and promotes cancer-cell proliferation and metastasis

Background/purpose

Long noncoding RNAs (lncRNAs) have emerged as important regulators and biomarkers of tumor development and progression. This study investigated the clinical significance, biological functions, and underlying mechanisms of long intergenic non-protein-coding RNA 1296 (LINC01296) in prostate cancer.

Materials and methods

LINC01296 expression in prostate cancer tissues and cell lines was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The correlation between LINC01296 expression and clinicopathologic characteristics of prostate cancer was analyzed using Kaplan–Meier analysis and the Cox proportional-hazard model. Small interfering RNA was used to suppress LINC01296, and knockdown efficiency was examined by qRT-PCR. Cell Counting Kit 8 assay, colony-formation assay, migration and invasion assays, and Western blot assay were used to explore the role of LINC01296 in tumor progression further.

Results

LINC01296-expression level was higher in prostate cancer tissues and prostate cancer cells than in adjacent nontumor tissues and immortalized normal prostate stromal WPMY1 cells. LINC01296 expression was correlated with preoperative prostate specific antigen (P=0.002), lymph-node metastasis (P=0.035), Gleason score (P<0.001), and tumor stage (P=0.036). Patients with higher LINC01296 expression displayed advanced clinical features and shorter biochemical recurrence-free survival time than those with lower LINC01296 expression. Multivariate analysis showed that LINC01296 expression was an independent predictor of biochemical recurrence-free survival in prostate cancer. Additionally, LINC01296 knockdown inhibited prostate cancer-cell proliferation, migration, and invasion, demonstrated in an in vitro study involving regulation of PI3K–Akt–mTOR signaling and epithelial–mesenchymal transition.

Conclusion

The results demonstrated that LINC01296 is a novel molecule involved in prostate cancer development and progression, and thus is a potential biomarker of prognosis.