The long non-coding RNA PCAT-1 promotes prostate cancer cell proliferation through cMyc. Neoplasia. 2014;16:900-908. [PMID: 25425964 PMCID: PMC4240923 DOI: 10.1016/j.neo.2014.09.001]

Dysregulation of long non-coding RNA SNHG12 alters the viability, apoptosis, and autophagy of prostate cancer cells by regulating miR-195/CCNE1 axis

This study aimed to explore the role and mechanism of lncRNA small nucleolar RNA host gene 12 (SNHG12) in the development of prostate cancer (PCa). The expression of SNHG12 in the serum of PCa patients as well as PCa cells was determined, and then we investigated whether SNHG12 could act as a competing endogenous RNA (ceRNA) to mediate the development of PCa. Furthermore, the association between SNHG12 and activation of the PI3K/AKT/mTOR pathway was explored. SNHG12 expression was up-regulated in the serum of PCa patients as well as PCa cells. High expression of SNHG12 resulted in a poor prognosis of PCa patients. Moreover, suppression of SNHG12 inhibited viability and promoted apoptosis and autophagy of LNCaP cells. Furthermore, SNHG12 was found to act as a ceRNA to regulate the expression of Cyclin E1 (CCNE1) by sponging miR-195. Lastly, suppression of SNHG12 inhibited the activation of PI3K/AKT/mTOR pathway. Our results revealed that up-regulation of SNHG12 promoted the viability and inhibited apoptosis and autophagy of PCa cells by regulating CCNE1 expression by sponging miR-195. Moreover, activation of PI3K/AKT/mTOR pathway is a key downstream mechanism regulating SNHG12-mediated the development of PCa. Our findings provide an experimental basis for targeted therapy of PCa.

Biological and Clinical Relevance of Long Non-Coding RNA PCAT-1 in Cancer, A Systematic Review and Meta-Analysis

Long non-coding RNA (lncRNA) prostate cancer associated transcript 1 (PCAT-1) has been identified as a potential biomarker for the diagnosis and prognosis of various cancers. We performed this systematic review and meta-analysis to evaluate the role of dysregulation as well as the biological and clinical significance of lnc-PCAT-1 for predicting the malignancy status in several cancers. Two independent reviewers conducted an extensive search in electronic databases of Medline, Embase, Scopus, Web of Science and PubMed until the December of 2017. Five articles investigating the clinical significance of lncRNA PCAT-1, including 996 patients, were analyzed. Our results revealed that the increased PCAT-1 expression was related to overall survival (OS) (HR = 1.9, 95% CI: 1.13-3.18, P=0.015). Also, pooled results of the diagnostic data analysis demonstrated that PCAT-1 has a sensitivity of 0.59 and specificity of 0.66 for cancer diagnosis. Moreover, pooled area under curve was 0.62 (95% CI: 0.58–0.69). This meta-analysis revealed that lncRNA PCAT-1 could be served as a potential diagnostic and prognostic biomarker in various solid tumors.

Long non-coding RNA SNHG6 is upregulated in prostate cancer and predicts poor prognosis

Certain long non-coding RNAs (lncRNAs) have been reported to be differentially expressed in various human cancer types, including prostate cancer (PCa). PCa is the most commonly diagnosed cancer type in men and lacks sensitive and accurate biomarkers. Emerging studies have indicated that certain lncRNAs are dysregulated and have crucial roles in PCa progression. The present study reported that the novel lncRNA small nucleolar RNA host gene 6 (SNHG6) is overexpressed in PCa compared with that in normal prostate tissues. In The Cancer Genome Atlas and Taylor datasets, high expression of SNHG6 in PCa tissues was identified to be significantly associated with shorter disease-free survival. In order to reveal the potential mechanisms of the role of SNHG6 in PCa, SNHG6-associated protein-protein interaction networks were constructed. Bioinformatics analysis revealed that these SNHG6-interacting genes were associated with translation, nuclear-transcribed mRNA catabolic process, ribosomal RNA processing and mRNA splicing. Although further functional validation is warranted, the present study suggests that SNHG6 is a potential novel therapeutic target and prognostic biomarker for PCa.

CARLo-7-A plausible biomarker for bladder cancer

Cancer is defined as undifferentiated and unchecked growth of cells damaging the surrounding tissue. Cancers manifest altered gene expression. Gene expression is regulated by a diverse array of non-protein-coding RNA. Aberrant expression of long non-coding RNAs (lncRNAs) has been recently found to have functional consequences in cancers. In the current study, we report CARLo-7 as the only bladder cancer-specific lncRNA from the CARLos cluster. The expression of this lncRNA correlates with bladder cancer grade. We propose that CARLo-7 has an oncogenic potential and might be regulator of cell proliferation. Furthermore, by comparison the expression of proto-oncogene MYC, which is the only well-annotated gene close to the cancer - associated linkage disequilibrium blocks of this region, does not show a pronounced change in expression between the low- and high-grade tumours. Our results indicate that CARlo-7 can act as a prognostic marker for bladder cancer.

SNHG6 is upregulated in primary breast cancers and promotes cell cycle progression in breast cancer-derived cell lines

BACKGROUND

Long non-coding RNAs (lncRNAs) are known as RNAs that do not encode proteins and that are more than 200 nucleotides in size. Previously, it has been found that LncRNAs play crucial roles in normal cellular processes, including proliferation and apoptosis. A growing body of evidence suggests that lncRNAs may also play regulatory roles in the initiation, progression and metastasis of various malignancies, including breast cancer. SNHG6 is a lncRNA that has previously been found to contribute to the initiation and progression of hepatocellular and gastric carcinomas. In this study, the clinical significance of SNHG6 expression in breast cancer was investigated.

METHODS

SNHG6 expression in primary breast cancer tissues was assessed using RT-qPCR. The functional role of SNHG6 was investigated using RNAi-mediated silencing and exogenous overexpression in breast cancer-derived cells. MTT, colony formation, cell cycle, apoptosis and senescence assays were used to determine the impact of SNHG6 expression on breast cancer-derived cells. The effect of SNHG6 on the migration and epithelial-to-mesenchymal transition (EMT) of breast cancer-derived cells was determined using scratch wound healing and immunofluorescence assays, respectively.

RESULTS

We found that the expression of SNHG6 was significantly upregulated in primary high-grade and progesterone receptor (PR)-positive breast tumours. Additional siRNA-based experiments revealed that SNHG6 silencing led to G1 cell cycle arrest in SK-BR-3 and MDA-MB-231 breast cancer-derived cells. Moreover, we found that SNHG6 silencing led to suppressed breast cancer cell proliferation by inducing apoptosis and senescence. Our data also indicate that SNHG6 may contribute to the migration and EMT of breast cancer cells.

CONCLUSIONS

Our results indicate that lncRNA SNHG6 is involved in breast cancer development and may be considered as a potential biomarker for the diagnosis, prognosis and treatment of breast cancer.

PCAT-1: A Novel Oncogenic Long Non-Coding RNA in Human Cancers

Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides (nts) without obvious protein coding potential. lncRNAs act as multiple roles in biological processes of diseases, especially carcinomas. Prostate cancer associated transcript-1 (PCAT-1) is an oncogenic lncRNA that identified by RNA-Sequence in prostate cancer. High expression of PCAT-1 is observed in different types of cancers, including prostate cancer, colorectal cancer, hepatocellular cancer and gastric cancer. High expressed PCAT-1 is correlated with poor overall survival. Furthermore, PCAT-1 regulates cancer cell proliferation, apoptosis, migration and invasion. Additionally, PCAT-1 is involved in EMT and Wnt/β-catenin-signaling pathway. In this review, we focus on the implication of PCAT-1 in human cancers.

Long non-coding RNAs in prostate cancer: Biological and clinical implications

Prostate cancer (PCa) is a major health issue in the Western world. Current clinical imperatives for this disease include better stratification of indolent versus aggressive disease to enable improved patient management, as well as the identification of more effective therapies for the prevention and treatment of metastatic and therapy-resistant PCa. The advent of next-generation transcriptomics led to the identification of an important class of molecules, long non-coding RNAs (lncRNAs). LncRNAs have critical functions in normal physiology, but their dysregulation has also been implicated in the development and progression of a variety of cancers, including PCa. Importantly, a subset of lncRNAs are highly prostate-specific, suggesting potential for utility as both biomarkers and therapeutic targets. In this review, we summarise the biology of lncRNAs and their mechanisms of action in the development and progression of prostate cancer. Additionally, we cast a critical eye over the potential for this class of molecules to impact on clinical practice.

The H19/let-7 feedback loop contributes to developmental dysplasia and dislocation of the hip

Developmental dysplasia and dislocation of the hip (DDH) is the most common type of lower limb deformity in pediatric orthopedics. The mechanism of the signaling pathway has been studied in depth. However, the role of epigenetic regulation, such as lncRNA, is still far from clear. In this study, we successfully established a rat model of DDH and demonstrated that H19 was down-regulated in the development of DDH. Further, we constructed H19 knockdown (KD) and overexpression chondrocytes. H19 KD suppressed the proliferation of normal chondrocytes, while overexpression of H19 promoted cell proliferation of DDH chondrocytes. Finally, we revealed that H19 bound to let-7 and inhibited its function, acting as a competing endogenous RNA. Down-regulation of H19 is closely associated with DDH progression and H19 is an important epigenetic factor that regulates the proliferation of chondrocytes. H19 may thus be a potential clinical marker for DDH diagnosis and treatment.

Intricate crosstalk between MYC and non-coding RNAs regulates hallmarks of cancer

Myelocytomatosis viral oncogene homolog (MYC) plays an important role in the regulation of many cellular processes, and its expression is tightly regulated at the level of transcription, translation, protein stability, and activity. Despite this tight regulation, MYC is overexpressed in many cancers and contributes to multiple hallmarks of cancer. In recent years, it has become clear that noncoding RNAs add a crucial additional layer to the regulation of MYC and its downstream effects. So far, twenty-five microRNAs and eighteen long noncoding RNAs that regulate MYC have been identified. Thirty-three miRNAs and nineteen lncRNAs are downstream effectors of MYC that contribute to the broad oncogenic role of MYC, including its effects on diverse hallmarks of cancer. In this review, we give an overview of this extensive, multilayered noncoding RNA network that exists around MYC. Current data clearly show explicit roles of crosstalk between MYC and ncRNAs to allow tumorigenesis.

Prostate Cancer Genomic Subtypes

Over the last decade, advancements in massively-parallel DNA sequencing and computational biology have allowed for unprecedented insights into the fundamental mutational processes that underlie virtually every major cancer type. Two major cancer genomics consortia-The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC)-have produced rich databases of mutational, pathological, and clinical data that can be mined through web-based portals, allowing for correlative studies and testing of novel hypotheses on well-powered patient cohorts.In this chapter, we will review the impact of these technological developments on the understanding of molecular subtypes that promote prostate cancer initiation, progression, metastasis, and clinical aggression. In particular, we will focus on molecular subtypes that define clinically-relevant patient cohorts and assess how a better understanding of how these subtypes-in both somatic and germline genomes-may influence the clinical course for individual men diagnosed with prostate cancer.

Prostate Cancer Transcriptomic Subtypes

While the DNA of a tumor is often equated to a fingerprint or its unique genetic identify, a tumor's RNA profile represents a complex dynamic state more akin to a tumors personality or distinct behavior. Of the 11 types of RNA, the translational and clinical focus in prostate cancer has been primarily on mRNA and lncRNA. The most common use of RNA-based biomarkers is to assess a tumor's aggressiveness or treatment sensitivity. However, multiple gene expression signatures have been developed to capture the functional state that results from canonical DNA alterations, including ERG fusions, SPOP mutations, and Rb loss. More commonly, these biomarkers have been used to develop over 30 prognostic gene expression signatures, three of which are now commercially available and being increasingly incorporated into clinical trials. In parallel, the ability to use microarray and RNAseq technologies have allowed high throughput methods of performing whole transcriptomic analyses. This has enabled the discovery and training of numerous predictive biomarker signatures rooted in biologically informed pathways to determine which tumors are more sensitive or resistant to various treatments, including androgen-deprivation therapy, radiotherapy, chemotherapy, and PARP inhibition. This chapter will review the various types of RNA, technologies available to assess gene expression, and describe the available gene expression signatures for prostate cancer.

PCAT-1: A pivotal oncogenic long non-coding RNA in human cancers

Prostate cancer-associated transcript 1 (PCAT-1) is a newly identified long non-coding RNA comprising two exons, located in the Chr8q24 gene desert approximately 725 kb upstream of the MYC oncogene. PCAT-1 is dysregulated and acts as an oncogene in different types of cancers and has been implicated in several processes correlated with carcinogenesis, such as cell proliferation, invasion, metastasis, apoptosis, cell cycle, chemoresistance, and homologous recombination. The mechanisms underlying the effects of PCAT-1 are complex and involve multiple factors and signaling pathways. In this paper, we systematically review the multiple pathological functions of PCAT-1 in diverse malignancies to elucidate its potential molecular mechanisms and to provide new directions for future research.

Role of BRCA Mutations in Cancer Treatment with Poly(ADP-ribose) Polymerase (PARP) Inhibitors

Inhibition of poly(ADP-ribose) polymerase (PARP) activity induces synthetic lethality in mutated BRCA1/2 cancers by selectively targeting tumor cells that fail to repair DNA double strand breaks (DSBs). Clinical studies have confirmed the validity of the synthetic lethality approach and four different PARP inhibitors (PARPi; olaparib, rucaparib, niraparib and talazoparib) have been approved as monotherapies for BRCA-mutated or platinum-sensitive recurrent ovarian cancer and/or for BRCA-mutated HER2-negative metastatic breast cancer. PARPi therapeutic efficacy is higher against tumors harboring deleterious germline or somatic BRCA mutations than in BRCA wild-type tumors. BRCA mutations or intrinsic tumor sensitivity to platinum compounds are both regarded as indicators of deficiency in DSB repair by homologous recombination as well as of favorable response to PARPi. However, not all BRCA-mutated or platinum-responsive patients obtain clinical benefit from these agents. Conversely, a certain percentage of patients with wild-type BRCA or platinum-resistant tumors can still get benefit from PARPi. Thus, additional reliable markers need to be validated in clinical trials to select patients potentially eligible for PARPi-based therapies, in the absence of deleterious BRCA mutations or platinum sensitivity. In this review, we summarize the mechanisms of action of PARPi and the clinical evidence supporting their use as anticancer drugs as well as the additional synthetic lethal partners that might confer sensitivity to PARPi in patients with wild-type BRCA tumors.

Dissecting LncRNA Roles in Renal Cell Carcinoma Metastasis and Characterizing Genomic Heterogeneity by Single-Cell RNA-seq

Long noncoding RNAs (lncRNA) have recently emerged as important regulators in cancer cell proliferation and metastasis. However, the role of lncRNAs in metastatic clear cell renal cell carcinoma (ccRCC) remains unclear. Here, single-cell RNA sequencing data were analyzed from primary renal cell carcinoma and paired metastatic renal cell carcinoma specimens, and characterized the expression profiles of over 10,000 genes, including 1,874 lncRNAs. Further analysis revealed that lncRNAs exhibit cancer type- and tissue-specific expression across ccRCC cells. Interestingly, a number of lncRNAs (n = 173) associated with ccRCC metastasis, termed ccRCC metastasis-associated lncRNAs (CMAL). Moreover, functional analysis based on a CMAL-PCG coexpression network revealed that CMALs contribute to cell adhesion, immune response, and cell proliferation. In combination with survival analysis, 12 CMALs were identified that participate in TNF and hypoxia-inducible factor 1 signaling to promote ccRCC metastasis. Further investigation on intratumoral heterogeneity showed that some CMALs are selectively expressed in different subpopulations. IMPLICATIONS: To explore ccRCC metastasis, the current study performed a global dissection of lncRNAs and a complex genomic analysis of ccRCC tumor heterogeneity. The data shed light on the discovery of potential lncRNA biomarkers and lncRNA therapeutic targets.

Overexpression of AR-regulated lncRNA TMPO-AS1 correlates with tumor progression and poor prognosis in prostate cancer

BACKGROUND

Prostate cancer (PCa) is a leading cause of death in males all over the world; besides, the diagnosis and therapy of it are still challenging. Researchers have revealed that long non-coding RNAs (lncRNAs) play important roles in the genesis and progression of human cancers, including PCa.

METHODS

Bioinformatics analysis and Kaplan-Meier survival analysis were utilized to confirm TMPO-AS1 as a diagnostic and prognostic marker. The TMPO-AS1 levels in both patient tissues and PCa cell lines were determined by qRT-PCR analysis. Moreover, the chromatin immunoprecipitation (ChIP) assay identified that TMPO-AS1 was a direct target of AR. The effect of overexpression or knockdown of TMPO-AS1 on cell proliferation, migration, cell cycle, and cell apoptosis was assessed by using CCK-8, transwell assays, and flow cytometric analysis, respectively.

RESULTS

Based on primary screening, we found that TMPO-AS1 could be a useful diagnostic and prognostic marker for PCa, whose expression was upregulated in PCa samples and associated with poorer prognosis. Bioinformatics predictions revealed TMPO-AS1 was associated with a series of biological processes involved in PCa progression. In PCa cells, TMPO-AS1 was predominantly localized in the cytoplasm and directly down-regulated by AR. Gain/loss-of-function assays showed TMPO-AS1 overexpression increased cell proliferation by promoting cell cycle progression and promoted migration, but reduced apoptosis of PCa cells. In addition, TMPO-AS1 may be a diagnostic and prognostic marker in multiple cancer types.

CONCLUSIONS

AR-regulated lncRNA TMPO-AS1 functioned as an oncogenic lncRNA in PCa, and may be a potential diagnostic and prognostic biomarker to be used as a therapeutic target for PCa.

Evaluation of serum exosomal LncRNA-based biomarker panel for diagnosis and recurrence prediction of bladder cancer

Exosomes are small membrane vesicles released by many cells. These vesicles can mediate cellular communications by transmitting active molecules including long non‐coding RNAs (lncRNAs). In this study, our aim was to identify a panel of lncRNAs in serum exosomes for the diagnosis and recurrence prediction of bladder cancer (BC). The expressions of 11 candidate lncRNAs in exosome were investigated in training set (n = 200) and an independent validation set (n = 320) via quantitative real‐time PCR. A three‐lncRNA panel (PCAT‐1, UBC1 and SNHG16) was finally identified by multivariate logistic regression model to provide high diagnostic accuracy for BC with an area under the receiver‐operating characteristic curve (AUC) of 0.857 and 0.826 in training set and validation set, respectively, which was significantly higher than that of urine cytology. The corresponding AUCs of this panel for patients with Ta, T1 and T2‐T4 were 0.760, 0.827 and 0.878, respectively. In addition, Kaplan‐Meier analysis showed that non‐muscle‐invasive BC (NMIBC) patients with high UBC1 expression had significantly lower recurrence‐free survival (P = 0.01). Multivariate Cox analysis demonstrated that UBC1 was independently associated with tumour recurrence of NMIBC (P = 0.018). Our study suggested that lncRNAs in serum exosomes may serve as considerable diagnostic and prognostic biomarkers of BC.

LncRNA PCAT-1 in gastrointestinal cancers: A meta-analysis

BACKGROUND

Prostate-cancer-associated ncRNA transcript 1 (PCAT-1), a newly discovered lncRNA, was implicated in the progression of multiple tumors. We conducted a systematic review and meta-analysis to determine its prognostic potential for gastrointestinal cancers.

METHODS

A literature survey was conducted by searching the PubMed, Web of Science, Cochrane Library, Embase together with Wanfang, and China National Knowledge Infrastructure (CNKI) database for articles published as of October 15, 2017. Hazard ratio (HR) or odds ratio (OR) with 95% confidence intervals (95% CIs) were calculated to demonstrate prognostic value of PCAT-1 using Stata 12.0 software.

RESULTS

A total of 6 studies with 961 cases were pooled in the analysis to evaluate the prognostic value of PCAT-1 in gastrointestinal cancers. Increased PCAT-1 expression was significantly correlated with poor overall survival (OS) (HR = 1.04, 95% CI: 1.02-1.06). Statistical significance was also observed in subgroup meta-analysis stratified by cancer type, histology type, sample size, and analysis type. Additionally, high expression of PCAT-1 was significantly associated with deeper tumor invasion (OR = 4.46, 95% CI: 3.00-6.63), positive lymph node metastasis (OR = 3.76, 95% CI: 1.39-10.16), and advanced clinical stage (OR = 4.09, 95% CI: 1.55-10.82).

CONCLUSION

High expression of PCAT-1 was related to poor prognosis and could be a promising biomarker of clinicopathologic features in gastrointestinal cancers. More studies will be necessary to verify and strengthen the clinical value of PCAT-1 in gastrointestinal cancers.

Regulation of DNA Double-Strand Break Repair by Non-Coding RNAs

DNA double-strand breaks (DSBs) are deleterious lesions that are generated in response to ionizing radiation or replication fork collapse that can lead to genomic instability and cancer. Eukaryotes have evolved two major pathways, namely homologous recombination (HR) and non-homologous end joining (NHEJ) to repair DSBs. Whereas the roles of protein-DNA interactions in HR and NHEJ have been fairly well defined, the functions of small and long non-coding RNAs and RNA-DNA hybrids in the DNA damage response is just beginning to be elucidated. This review summarizes recent discoveries on the identification of non-coding RNAs and RNA-mediated regulation of DSB repair.

Upregulation of gastric adenocarcinoma predictive long intergenic non-coding RNA promotes progression and predicts poor prognosis in perihilar cholangiocarcinoma

Perihilar cholangiocarcinoma (PHCC) is one of the most aggressive and complex types of cancer with a poor survival. Despite advances in PHCC diagnosis and treatment, the biology of this tumor remains poorly understood. Recent studies have suggested long non-coding RNAs (lncRNAs) as crucial determinants of cancer progression. However, the role of lncRNAs in PHCC is rarely reported and the function of gastric adenocarcinoma predictive long intergenic non-coding RNA (GAPLINC) in PHCC has yet to be elucidated. The present study observed a significant upregulation of GAPLINC in PHCC cell lines and clinical specimens (P<0.05). Furthermore, by comparing clinicopathological characteristics with expression data, high GAPLINC expression was revealed to be associated with the T stage (P=0.013), N stage (P<0.001) and Tumor-Node-Metastasis stage (P<0.001) of PHCC. Furthermore, Kaplan-Meier analysis demonstrated that GAPLINC expression was associated with poor overall survival and progression-free survival rates in PHCC. Furthermore, univariate and multivariate COX regression analyses identified high GAPLINC expression as a risk factor of a poor prognosis in PHCC. GAPLINC upregulation promoted the migration and invasion of PHCC cells in Transwell and Matrigel assays, respectively, while GAPLINC deficiency inhibited PHCC cell metastasis. Furthermore, PHCC cells with GAPLINC overexpression exhibited markedly increased proliferation ability in a Cell Counting kit-8 assay. However, GAPLINC interference significantly suppressed cell proliferation. In conclusion, GAPLINC may promote PHCC progression and may serve as a potential prognostic marker and therapeutic target of PHCC.

Genomic Hallmarks and Structural Variation in Metastatic Prostate Cancer

While mutations affecting protein-coding regions have been examined across many cancers, structural variants at the genome-wide level are still poorly defined. Through integrative deep whole-genome and -transcriptome analysis of 101 castration-resistant prostate cancer metastases (109X tumor/38X normal coverage), we identified structural variants altering critical regulators of tumorigenesis and progression not detectable by exome approaches. Notably, we observed amplification of an intergenic enhancer region 624 kb upstream of the androgen receptor (AR) in 81% of patients, correlating with increased AR expression. Tandem duplication hotspots also occur near MYC, in lncRNAs associated with post-translational MYC regulation. Classes of structural variations were linked to distinct DNA repair deficiencies, suggesting their etiology, including associations of CDK12 mutation with tandem duplications, TP53 inactivation with inverted rearrangements and chromothripsis, and BRCA2 inactivation with deletions. Together, these observations provide a comprehensive view of how structural variations affect critical regulators in metastatic prostate cancer.

Pathological bases and clinical impact of long noncoding RNAs in prostate cancer: a new budding star

Long non-coding RNAs (lncRNAs) are functional RNAs longer than 200 nucleotides. Recent advances in the non-protein coding part of human genome analysis have discovered extensive transcription of large RNA transcripts that lack coding protein function, termed non-coding RNA (ncRNA). It is becoming evident that lncRNAs may be an important class of pervasive genes involved in carcinogenesis and metastasis. However, the biological and molecular mechanisms of lncRNAs in diverse diseases are not yet fully understood. Thus, it is anticipated that more efforts should be made to clarify the lncRNA world. Moreover, accumulating evidence has demonstrated that many lncRNAs are dysregulated in prostate cancer (PC) and closely related to tumorigenesis, metastasis, and prognosis or diagnosis. In this review, we will briefly outline the regulation and functional role of lncRNAs in PC. Finally, we discussed the potential of lncRNAs as prospective novel targets in PC treatment and biomarkers for PC diagnosis.

Upregulation of the Long Noncoding RNA SNHG3 Promotes Lung Adenocarcinoma Proliferation

Lung cancer is the leading cause of cancer-associated mortalities worldwide. Non-small-cell lung cancer (NSCLC) is the main reason for cancer-relevant death and constitutes 80% of lung cancer cases. Long noncoding RNAs (lncRNAs) have been found to be related to different kinds of cancer. Long noncoding RNAs played important roles in regulating the pathological and physiological processes of numerous cancers. To explore novel lung adenocarcinoma-associated lncRNAs, we analyzed the TCGA database and found that the lncRNA SNHG3 was significantly upregulated in lung adenocarcinoma. Bioinformatic analysis showed that SNHG3 may play key roles in regulating RNA splicing, tRNA processing, signal transduction, cell adhesion, transcription, and apoptosis. We also performed functional experiments to explore the roles of SNHG3 in lung adenocarcinoma cells. We found that SNHG3 promoted proliferation, cell cycle, and suppressed cell apoptosis of lung adenocarcinoma, suggesting that SNHG3 acted as an oncogene in lung adenocarcinoma. We believe that this study will provide a potential new therapeutic and prognostic target for lung adenocarcinoma.

Analysis of the Cancer Genome Atlas Data Reveals Novel Putative ncRNAs Targets in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the prevalent type of primary liver malignancy. Different noncoding RNAs (ncRNAs) that negatively regulate gene expression, such as the microRNAs and the long ncRNAs (lncRNAs), have been associated with cell invasiveness and cell dissemination, tumor recurrence, and metastasis in HCC. To evaluate which regulatory ncRNAs might be good candidates to disrupt HCC proliferation pathways, we performed both unsupervised and supervised analyses of HCC expression data, comparing samples of solid tumor tissue (TP) and adjacent tissue (NT) of a set of patients, focusing on ncRNAs and searching for common mechanisms that may shed light in future therapeutic options. All analyses were performed using the R software. Differential expression (total RNA and miRNA) and enrichment analyses (Gene Ontology + Pathways) were performed using the package TCGABiolinks. As a result, we improved the set of lncRNAs that could be the target of future studies in HCC, highlighting the potential of FAM170B-AS1 and TTN-AS1.

Transcriptome analysis reveals a long non-coding RNA signature to improve biochemical recurrence prediction in prostate cancer

Despite highly successful treatments for localized prostate cancer (PCa), prognostic biomarkers are needed to improve patient management and prognosis. Accumulating evidence suggests that long noncoding RNAs (lncRNAs) are key regulators with biological and clinical significance. By transcriptome analysis, we identified a set of consistently dysregulated lncRNAs in PCa across different datasets and revealed an eight-lncRNA signature that significantly associated with the biochemical recurrence (BCR)-free survival. Based on the signature, patients could be classified into high- and low-risk groups with significantly different survival (HR = 2.19; 95% CI = 1.67-2.88; P < 0.0001). Validations in the validation cohorts and another independent cohort confirmed its prognostic value for recurrence prediction. Multivariable analysis showed that the signature was independent of common clinicopathological features and stratified analysis further revealed its role in elevating risk stratification of current prognostic models. Additionally, the eight-lncRNA signature was able to improve on the CAPRA-S score for the prediction of BCR as well as to reflect the metastatic potential of PCa. Functional characterization suggested that these lncRNAs which showed PCa-specific expression patterns may involve in critical processes in tumorigenesis. Overall, our results demonstrated potential application of lncRNAs as novel independent biomarkers. The eight-lncRNA signature may have clinical potential for facilitating further stratification of more aggressive patients who would benefit from adjuvant therapy.

MALAT1: a druggable long non-coding RNA for targeted anti-cancer approaches

The deeper understanding of non-coding RNAs has recently changed the dogma of molecular biology assuming protein-coding genes as unique functional biological effectors, while non-coding genes as junk material of doubtful significance. In the last decade, an exciting boom of experimental research has brought to light the pivotal biological functions of long non-coding RNAs (lncRNAs), representing more than the half of the whole non-coding transcriptome, along with their dysregulation in many diseases, including cancer.In this review, we summarize the emerging insights on lncRNA expression and functional role in cancer, focusing on the evolutionary conserved and abundantly expressed metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) that currently represents the best characterized lncRNA. Altogether, literature data indicate aberrant expression and dysregulated activity of MALAT1 in human malignancies and envision MALAT1 targeting as a novel treatment strategy against cancer.

Long non-coding RNA SNHG1 predicts a poor prognosis and promotes colon cancer tumorigenesis

Colon cancer is the main cause of cancer mortality worldwide. Its poor prognosis is mainly ascribed to high recurrence rates. Identifying novel prognostic biomarkers and therapeutic key points for management is crucial and important. Long non-coding RNAs (lncRNAs) are a class of RNAs, which have various roles in carcinogenicity and molecular mechanisms. The lncRNA small nucleolar RNA host gene 1 (SNHG1) contributes to the promotion of tumor development, however, the connections between SNHG1 and colon cancer are still unclear. The aim of the present study was to investigate the clinical significance, the biological functions, and the potential mechanism of SNHG1 in colon cancer. In the present study, we referred to the Oncomine database and used RT-qPCR to determine that SNHG1 expression was significantly higher both in colon cancer tissues and cancerous cell lines than in normal samples. Cell functional experiments were performed after knockdown of SNHG1, including Cell Counting Kit-8 assay, colony formation assay, Transwell^® assay, and flow cytometric analyses of cell apoptosis, which suggested that SNHG1 stimulated colon cancer cell proliferation, promoted cell invasion and migration, and inhibited apoptosis. Immunohistochemical staining and western blotting experiments revealed that in colon cancer cells with SNHG1 knockdown, β-catenin, c-Myc and cyclin D1 protein levels were decreased, while E-cadherin was increased, which suggested that SNHG1 promoted colon cancer cell proliferation, migration and invasion through the Wnt/β-catenin signaling pathway. Our results indicated that SNHG1 and its interrelated components may be future therapeutic targets of carcinoma of the colon.

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.

ncRNA-disease association prediction based on sequence information and tripartite network

Background

Current technology has demonstrated that mutation and deregulation of non-coding RNAs (ncRNAs) are associated with diverse human diseases and important biological processes. Therefore, developing a novel computational method for predicting potential ncRNA-disease associations could benefit pathologists in understanding the correlation between ncRNAs and disease diagnosis, treatment, and prevention. However, only a few studies have investigated these associations in pathogenesis.

Results

This study utilizes a disease-target-ncRNA tripartite network, and computes prediction scores between each disease-ncRNA pair by integrating biological information derived from pairwise similarity based upon sequence expressions with weights obtained from a multi-layer resource allocation technique. Our proposed algorithm was evaluated based on a 5-fold-cross-validation with optimal kernel parameter tuning. In addition, we achieved an average AUC that varies from 0.75 without link cut to 0.57 with link cut methods, which outperforms a previous method using the same evaluation methodology. Furthermore, the algorithm predicted 23 ncRNA-disease associations supported by other independent biological experimental studies.

Conclusions

Taken together, these results demonstrate the capability and accuracy of predicting further biological significant associations between ncRNAs and diseases and highlight the importance of adding biological sequence information to enhance predictions.

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.

Long noncoding RNA PCAT-14 induces proliferation and invasion by hepatocellular carcinoma cells by inducing methylation of miR-372

Long non-coding RNAs (lncRNAs) regulate oncogenesis by inducing methylation of CpG islands to silence target genes. Here we show that the lncRNA PCAT-14 is overexpressed in patients with hepatocellular carcinoma (HCC), and is associated with a poor prognosis after surgery. Our results demonstrate that PCAT-14 promotes proliferation, invasion, and cell cycle arrest in HCC cells. In addition, PCAT-14 inhibits miR-372 expression by inducing methylation of the miR-372 promoter. Simultaneously, miR-372 eliminates the effects of PCAT-14 on proliferation, invasion, and cell cycle in HCC cells. Moreover, PCAT-14 regulates expression of ATAD2 and activation of the Hedgehog pathway via miR-372. These findings indicate that PCAT-14 plays an important role in HCC, and may serve as a novel prognostic factor and therapeutic target.

Therapeutic Targeting of Long Non-Coding RNAs in Cancer

Long non-coding RNAs (lncRNAs) represent a significant population of the human transcriptome. Many lncRNAs exhibit cell- and/or tissue/tumor-specific expression, making them excellent candidates for therapeutic applications. In this review we discuss examples of lncRNAs that demonstrate the diversity of their function in various cancer types. We also discuss recent advances in nucleic acid drug development with a focus on oligonucleotide-based therapies as a novel approach to inhibit tumor progression. The increased success rates of nucleic acid therapeutics provide an outstanding opportunity to explore lncRNAs as viable therapeutic targets to combat various aspects of cancer progression.

Carcinogenesis in prostate cancer: The role of long non-coding RNAs

LncRNAs appear to play a considerable role in tumourigenesis through regulating key processes in cancer cells such as proliferative signalling, replicative immortality, invasion and metastasis, evasion of growth suppressors, induction of angiogenesis and resistance to apoptosis. LncRNAs have been reported to play a role in prostate cancer, particularly in regulating the androgen receptor signalling pathway. In this review article, we summarise the role of 34 lncRNAs in prostate cancer with a particular focus on their role in the androgen receptor signalling pathway and the epithelial to mesenchymal transition pathway.

Regulatory role of long non-coding RNAs during reproductive disease

Long non-coding RNA (lncRNA) is a group of RNAs with broad biogenesis, which are longer than 200 nt and highly conserved in their secondary and tertiary structures. lncRNA that broadly participates in varied physiological processes in organisms has abundant biological function and can regulate expression of target genes at transcriptional, post-transcriptional and epigenetic levels. LncRNAs can also affect the development of diseases, and therefore be used to diagnose and treat diseases. With new sequencing and microarray techniques, hundreds of lncRNAs involved in reproductive disorders have been identified, but their functions in these disorders are undefined. In this paper, we reviewed the studies on how lncRNAs participate in the development of reproductive disorders, hoping our outcome can instruct the future study and provide new biomarkers and therapies for reproductive disorders.

LncRNA PCAT-1 promotes tumour growth and chemoresistance of oesophageal cancer to cisplatin

Oesophageal cancer (OC) is one of the most fatal malignancies in the world, and chemoresistance restricts the therapeutic outcome of OC. Long noncoding RNA (lncRNA) was reported to play roles in multiple cancer types. Yet, the function of lncRNA in chemoresistance of OC has not been reported. A lncRNA gene, PCAT-1, showed higher expression in OC tissues, especially higher in secondary OC compared with normal mucosa tissues. Overexpression of PCAT-1 increased the proliferation rate and growth of OC cells. Inhibition of PCAT-1 decreased proliferation and growth of OC cells, and increased cisplatin chemosensitivity. In a mouse OC xenograft model, PCAT-1 inhibition repressed OC growth in vivo. Therefore, PCAT-1 may potentially serve as a therapeutic target for treating OC. PCAT-1 promotes development of OC and represses the chemoresistance of OC to cisplatin, and silencing of PCAT-1 may be a therapeutic strategy for treating OC.

Multiple Functions of Long Non-Coding RNAs in Oxidative Stress, DNA Damage Response and Cancer Progression

In addition to aberrant alternation of transcriptome, it is now suggested that dysregulation of the non-coding transcripts, particularly long non-coding RNAs (lncRNAs), which comprise the majority of the genome, is contributed to cancer initiation and progression. As the result of recent huge efforts, the possible roles of numerous lncRNAs in the human cancers were characterized, as well as various strategies with inhibitory effects to target these transcripts on the transformed cells. Moreover, DNA damage response (DDR) pathway is a complex regulatory network responsible for the identification of disruptions in DNA structure, integrity and stability- it is reported to be associated with the up-regulation and down-regulation of lncRNAs. This review explores the involvement of the various lncRNAs in different human cancers, afterwards discusses the association of the lncRNAs expression with the DDR and oxidative stress, which are implicated in a myriad pathophysiological and physiological intra- and extracellular damages. J. Cell. Biochem. 119: 223-236, 2018. © 2017 Wiley Periodicals, Inc.

The long non-coding RNA PARROT is an upstream regulator of c-Myc and affects proliferation and translation

Long non-coding RNAs are important regulators of gene expression and signaling pathways. The expression of long ncRNAs is dysregulated in cancer and other diseases. The identification and characterization of long ncRNAs is often challenging due to their low expression level and localization to chromatin. Here, we identify a functional long ncRNA, PARROT (Proliferation Associated RNA and Regulator Of Translation) transcribed by RNA polymerase II and expressed at a relatively high level in a number of cell lines. The PARROT long ncRNA is associated with proliferation in both transformed and normal cell lines. We characterize the long ncRNA PARROT as an upstream regulator of c-Myc affecting cellular proliferation and translation using RNA sequencing and mass spectrometry following depletion of the long ncRNA. PARROT is repressed during senescence of human mammary epithelial cells and overexpressed in some cancers, suggesting an important association with proliferation through regulation of c-Myc. With this study, we add to the knowledge of cytoplasmic functional long ncRNAs and extent the long ncRNA-Myc regulatory network in transformed and normal cells.

Transcriptome analysis reveals dysregulated long non-coding RNAs and mRNAs associated with extrahepatic cholangiocarcinoma progression

The incidence of extrahepatic cholangiocarcinoma (ECC) is the highest of all the cholangiocarcinoma cases. However, the molecular mechanism of ECC genesis and progression remains unclear. Long non-coding RNAs (lncRNAs) have been revealed to perform critical regulatory roles in cancer biology. In order to understand lncRNA expression patterns and their potential function in ECC, a transcriptome analysis of lncRNA and mRNA expression was performed in ECC and paired adjacent non-cancerous tissues using Agilent human lncRNA + mRNA arrayV4.0 (4×180 K format). It was identified that 268 lncRNAs and 459 mRNAs were differentially expressed in ECC. Among these, 78 lncRNAs and 66 mRNAs were upregulated >2-fold compared with adjacent non-cancerous tissues, and 190 lncRNAs and 393 mRNAs were downregulated in the ECC samples. Differences in lncRNA expression between ECC and paired adjacent non-cancerous tissues were confirmed using reverse transcription-quantitative polymerase chain reactionas proof of principle. Functional analysis of co-expressed mRNAs with lncRNAs indicated that these dysregulated lncRNAsmay be involved in known ECC-associated biological processes and pathways. The present findings indicated that mRNAs and lncRNAs perform important roles in the development and progression of ECC. The present findings may lay the foundation for future efforts to understand the role of lncRNAs and develop novel biomarkers in ECC.

Upregulation of long noncoding RNA LOC440040 promotes tumor progression and predicts poor prognosis in patients with prostate cancer

Background/purpose

Long noncoding RNAs (lncRNAs) play a functional role in the initiation and progression of prostate cancer (PCa). This study aimed to determine differentially expressed lncRNA through high-throughput sequencing technology and investigate its expression, biological function and clinical correlation with PCa.

Materials and methods

Candidate lncRNAs were identified through microarray screening and bioanalysis. The expression of lncRNA LOC440040 in PCa tissues and cell lines was determined by reverse-transcription polymerase chain reaction. The relationship between LOC440040 level and clinicopathological characteristics was analyzed by paired t-test or chi-square test, and its association with patient prognosis was assessed by the Kaplan–Meier method. The effects of LOC440040 on PC-3 and 22RV1 cells were evaluated by Cell Counting Kit-8 (CCK-8), migration, invasion and colony formation assays.

Results

LOC440040 expression was upregulated in PCa tissues and cell lines. Clinicopathological analysis showed that patients with high LOC440040 expression exhibited more advanced clinical features and shorter overall survival than those with low LOC440040 expression. Multivariate regression analysis revealed that LOC440040 expression was an independent prognostic factor in patients with PCa. Knockdown of LOC440040 inhibited PCa cell proliferation, migration and invasion.

Conclusion

LOC440040 may play an oncogenic role in PCa initiation and progression. This lncRNA could be a novel molecular prognostic biomarker and a potential therapeutic target for PCa.

Long non-coding RNA PCAT-1 contributes to tumorigenesis by regulating FSCN1 via miR-145-5p in prostate cancer

Prostate cancer associated lncRNA transcript 1 (PCAT-1) has been identified as an oncogenic long non-coding RNA (lncRNA) in some solid tumors, including prostate cancer (PC). However, the molecular mechanism of PCAT-1 involved in PC is poorly defined. In this study, we found that PCAT-1 expression was up-regulated and miR-145-5p expression was down-regulated in PC tissues and cells. Function analysis indicated that PCAT-1 overexpression promoted proliferation, migration, invasion and inhibited apoptosis of PC cells. Rescue experiments demonstrated that miR-145-5p restoration attenuated the promotive effects of PCAT1 on PC progression, while Fascin-1 (FSCN1) upregulation relieved the anti-cancer role of miR-145-5p in PC. Mechanical analysis discovered that PCAT-1 could act as a miR-145-5p sponge to modulate FSCN1 expression. In conclusion, these findings suggested that PCAT-1 accelerated PC cell proliferation, migration, invasion and suppressed apoptosis by up-regulating FSCN1 mediated via miR-145-5p, hinting a potential therapeutic strategy for PC patients.

Long noncoding RNA PCAT-1 promotes invasion and metastasis via the miR-129-5p-HMGB1 signaling pathway in hepatocellular carcinoma

OBJECTIVE

The long non-coding RNA (lncRNA) prostate cancer-associated transcript 1(PCAT-1) has been shown to be dysregulated and exert vital roles in tumorigenesis and progression of various malignancies. However, the precise molecular mechanism in the metastasis and invasion of HCC remain unclear.

METHODS

The expression levels of PCAT1 derived from human HCC tissues and cell lines were analyzed through quantitative real-time PCR. QRT-PCR was also applied to detect the expression of HMGB1 and miR-129-5p. Wound healing assay and transwell assays were performed to analyze cell migration and invasion ability. The mRNA levels and protein expression of HMGB1 were detected by western-blotting analysis and immunohistochemistry, respectively. Luciferase assays were used to investigate binding seeds beteen miRNA-129-5p and other transcripts, such as PCAT-1, HMGB1.

RESULT

In this study, our founding demonstrated that PCAT-1 was not only aberrantly upregulated in HCC tissues and cell lines, but also associated with TNM stage, metastasis and Histological grade. In vitro, downregulation of PCAT-1 could reduce the invasion and migration of HCC cells. Moreover, our results showed that PCAT-1 could act as an endogenous RNA by directly binding to miR-129-5p. In addition, Luciferase reporter assay and western blotting analyses showed that PCAT-1 repressed inhibitory effect of miR-129-5p and reverse high mobility group box 1 (HMGB1) expression, a target gene of miR-129-5p.

CONCLUSION

PCAT-1 functions as competing endogenous RNA (ceRNA) to provide a better understanding for HCC metastasis, and serves as a potential diagnostic and therapeutic target via PCAT-1/miR-129-5p/HMGB1 regulatory crosstalk for the deadly disease.

Knockdown of long non-coding RNA prostate cancer-associated ncRNA transcript 1 inhibits multidrug resistance and c-Myc-dependent aggressiveness in colorectal cancer Caco-2 and HT-29 cells

The long non-coding RNA (lncRNA) prostate cancer-associated ncRNA transcript 1 (PCAT-1) has been shown to promote prostate cancer cell proliferation through c-Myc and is associated with the poor prognosis of CRC patients. In the current study, it was hypothesized that the effect of PCAT-1 on the aggressiveness of CRC cells was dependent on the function of c-Myc. Human CRC cell lines Caco-2 and HT-29 were transfected with specific PCAT-1 shRNAs, and cell migration, invasiveness, and resistance to 5-fluorouracil were measured. To elucidate the role of c-Myc in PCAT-1 function, c-Myc was overexpressed in PCAT-1-silenced CRC cells and the effect of c-Myc overexpression on the aggressiveness of PCAT-1-silenced cells was detected. The results showed that knockdown of PCAT-1 in CRC cells suppressed cell motility and invasiveness, and sensitized the cells to 5-fluorouracil, as evidenced by the reduced viability and induced apoptosis in PCAT-1-silenced cells compared to the parental cells in response to 5-fluorouracil treatment. The expression of c-Myc in PCAT-1-silenced CRC cells was down-regulated, and forced expression of c-Myc partially restored the invasiveness in PCAT-1-silenced cells. In summary, the findings outlined in the current study suggest that PCAT-1 regulates the invasiveness and drug resistance in CRC cells and that PCAT-1 may promote CRC cell invasion by modulating the expression of c-Myc.

Long non-coding RNAs and prostate cancer

Long non‐coding RNAs (lncRNAs) are RNA transcripts larger than 200 nucleotides that do not code for proteins the aberrant expression of which has been documented in various types of cancer, including prostate cancer. Lack of appropriate sensitive and specific biomarkers for prostate cancer has led to overdiagnosis and overtreatment, making lncRNAs promising novel biomarkers as well as therapeutic targets for the disease. The present review attempts to summarize the current knowledge of lncRNA expression patterns and mechanisms in prostate cancer, which contribute to carcinogenesis. In particular, we focused on lncRNAs regulated by androgen receptor and expressed in castration‐resistant prostate cancer.

Down regulation of the long non-coding RNA PCAT-1 induced growth arrest and apoptosis of colorectal cancer cells

AIMS

The long non-coding RNA (lncRNA) was reported to be involved in the progress of various cancers, however, its effect in colorectal cancer (CRC) remains unknown. The goal of the present study is to investigate the function role of lncRNA PCAT-1 in colorectal cancer.

MAIN METHODS

The expression of lncRNA PCAT-1 in four CRC cell lines was measured by real-time PCR, and two lncRNA PCAT-1 high expression cell lines were selected. LncRNA PCAT-1 in these two CRC cell lines was down-regulated by shRNA, and the stable transfected cells were established. Functional involvement of lncRNA PCAT-1 in proliferation and apoptosis of the two CRC cells were evaluated in vitro. Mover, the effect of lncRNA PCAT-1 in tumor proliferation was also evaluated in CRC cell xenograft.

KEY FINDINGS

The results showed that down-regulation of lncRNA PCAT-1 in CRC cells inhibited proliferation, blocked cell cycle transition, and suppressed the expression of cyclins and c-myc. The apoptosis cell proportion was elevated with increased expression of pro-apoptotic proteins and decreased anti-apoptotic proteins in lncRNA PCAT-1 knock down cells. Forced over-expression of c-myc in PCAT-1 down-regulated CRC cells increased the level of cyclins. The xenograft growth in lncRNA PCAT-1 down-regulated cells was significantly inhibited along with the reduced proliferative cells.

SIGNIFICANCE

Our study revealed a tumorigenic effect of lncRNA PCAT-1 in CRC cells, and this effect is partly dependent on the inhibition of c-myc.

Aberrant Methylation of MEG3 Functions as a Potential Plasma-Based Biomarker for Cervical Cancer

Methylation alterations of specific genes have recently been identified as diagnostic biomarkers for human cancers. Although MEG3 has been proved to be a tumor suppressor in cervical cancer according to our previous study, the diagnostic value of MEG3 methylation in plasma is still unknown. Therefore, the aim of this study is to identify a novel epigenetic biomarker for cervical cancer. In the current study, the level of MEG3 methylation was evaluated using methylation-specific polymerase chain reaction. The results showed that the level of MEG3 methylation was significantly higher in cervical cancer tissues and patients' plasmas than those in adjacent normal tissues and plasmas of healthy participants respectively. Moreover, the accuracy was good enough for MEG3 methylation in plasma to discriminate CIN III patients from healthy participants. In addition, MEG3 methylation in plasma also has high discriminating power to predict HR-HPV infection and lymph node metastasis. Furthermore, hypermethylation of MEG3 in plasma was associated with worse recurrence-free and overall survival in cervical cancer patients. In conclusions, MEG3 methylation in plasma can serve as a diagnostic and prognostic biomarker for cervical cancer, providing useful information for clinical management.

Long Noncoding RNA and Cancer: A New Paradigm

In addition to mutations or aberrant expression in the protein-coding genes, mutations and misregulation of noncoding RNAs, in particular long noncoding RNAs (lncRNA), appear to play major roles in cancer. Genome-wide association studies of tumor samples have identified a large number of lncRNAs associated with various types of cancer. Alterations in lncRNA expression and their mutations promote tumorigenesis and metastasis. LncRNAs may exhibit tumor-suppressive and -promoting (oncogenic) functions. Because of their genome-wide expression patterns in a variety of tissues and their tissue-specific expression characteristics, lncRNAs hold strong promise as novel biomarkers and therapeutic targets for cancer. In this article, we have reviewed the emerging functions and association of lncRNAs in different types of cancer and discussed their potential implications in cancer diagnosis and therapy. Cancer Res; 77(15); 3965-81. ©2017 AACR.

lncRNAs and MYC: An Intricate Relationship

Long non-coding RNAs (lncRNAs) are emerging as important regulators of gene expression networks, acting either at the transcriptional level, by influencing histone modifications, or at the post-transcriptional level, by controlling mRNA stability and translation. Among the gene expression networks known to influence the process of oncogenic transformation, the one controlled by the proto-oncogene MYC is one of the most frequently deregulated in cancer. In B-cell lymphomas, the MYC gene is subject to chromosomal rearrangements that result in MYC overexpression. In many other cancers, the region surrounding MYC is subject to gene amplification. MYC expression is also controlled at the level of protein and mRNA stability. Neoplastic lesions affecting MYC expression are responsible for a drastic change in the number and the type of genes that are transcriptionally controlled by MYC, depending on differential promoter affinities. Transcriptome profiling of tumor samples has shown that several lncRNAs can be found differentially regulated by MYC in different cancer types and many of them can influence cancer cell viability and proliferation. At the same time, lncRNAs have been shown to be able to control the expression of MYC itself, both at transcriptional and post-transcriptional levels. Given that targeting the MYC-dependent transcriptional program has the potential to reach broad anticancer activity, molecular dissection of the complex regulatory mechanisms governing MYC expression will be crucial in the future for the identification of novel therapeutic strategies.

Expression Analysis of Long Non-Coding PCAT-1in Breast Cancer

Background: The prostate cancer-associated non-coding RNA transcript 1 (PCAT-1) is a newly identified long non- coding RNA whose participation in tumorigenesis of a variety of cancers has been observed. In the present study, we aimed at analysis of its expression in breast cancer patients. Materials and Methods: The expression of PCAT-1 was assessed using real-time reverse transcription polymerase chain reaction in tumor samples obtained from 47newly diagnosed breast cancer patients as well as their corresponding adjacent non-cancerous tissues (ANCTs). Results: We detected significant over-expression of PCAT-1 in 12/47 (25.5%) of tumoral tissues compared with their corresponding ANCTs. However, no significant association has been found between the levels of PCAT-1 transcripts and patients' clinical data such as tumor size, stage, grade, estrogen and progesterone receptors or Her2/neu status. Conclusion: PCAT-1 is possibly involved in the pathogenesis of fraction of breast cancers. Future studies are needed to evaluate its precise function in breast cancer.