Upregulation of long non coding RNA PCAT-1 contributes to cell proliferation, migration and apoptosis in hepatocellular carcinoma

Upregulation of Long Noncoding RNA PCAT1 in Iranian Patients with Colorectal Cancer and Its Performance as a Potential Diagnostic Biomarker

Background: Long noncoding RNAs (lncRNAs) as critical molecules play an essential role in the development of cancers. In colorectal cancer (CRC), various lncRNAs are related to cell proliferation, apoptosis, migration, and invasion. LncRNA prostate cancer-associated transcript 1 (PCAT-1), as an oncogenic factor, is a diagnostic biomarker that regulates cell proliferation, migration, invasion, and apoptosis. Methods: This study evaluated the relationship between PCAT-1, CRC occurrence, and pathological features of Iranian patients. The studied samples included 100 colorectal tumor tissues and 100 adjacent healthy tissues of Iranian CRC patients. RNAs were extracted from cancerous and noncancerous tissues to synthesize complementary DNA. The expression level of PCAT-1 was assessed using the real-time PCR method, and the data analysis was assessed using SPSS software. Results: In this study, expression level of PCAT-1 in tumor tissue was significantly increased in Iranian patients, and pathological studies of the patients had no significant relationship with the PCAT-1 expression profile. Conclusion: Our results suggested that the high expression of PCAT-1 resulted in the occurrence of colorectal tumor tissues in Iranian patients, which can be considered a diagnostic biomarker in CRC.

Long Non-Coding RNAs as Molecular Biomarkers in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a biliary system cancer that has the characteristics of strong invasiveness, poor prognosis, and few therapy choices. Furthermore, the absence of precise biomarkers for early identification and prognosis makes it hard to intervene in the early phase of initial diagnosis or recurring cholangiocarcinoma following surgery. Encouragingly, previous studies found that long non-coding RNA (lncRNA), a subgroup of RNA that is more than 200 nucleotides long, can affect cell proliferation, migration, apoptosis, and even drug resistance by altering numerous signaling pathways, thus reaching pro-cancer or anti-cancer outcomes. This review will take a retrospective view of the recent investigations on the work of lncRNAs in cholangiocarcinoma progression and the potential of lncRNAs serving as promising clinical biomarkers and therapeutic targets for CCA.

Long non‑coding RNA PCAT1 sponges miR‑134‑3p to regulate PITX2 expression in breast cancer

Breast cancer (BC) is the most prevalent cancer among women. Long non‑coding (lnc)RNAs and microRNAs (miRs) both regulate the expression of key genes in tumorigenesis. The present study aimed to explore the molecular mechanism of the prostate cancer‑associated transcript 1 (PCAT1)/miR‑134‑3p/pituitary homeobox 2 (PITX2) in BC. Reverse transcription‑quantitative PCR was performed to examine the expression of miR‑134‑3p. Cell proliferation, viability, cell cycle, apoptosis and migration were analyzed using Cell Counting Kit‑8, colony formation, flow cytometry, wound healing and Transwell assays. Protein expression levels were determined by western blotting. The present study demonstrated that PCAT1 was significantly highly expressed in BC cells. Knockdown of PCAT1 significantly inhibited cell proliferation, migration and invasion, but promoted apoptosis in human BC cell lines. The results of the dual‑luciferase assay showed that PCAT1 targeted miR‑134‑3p, and PITX2 was a potential target of miR‑134‑3p. Western blotting results demonstrated that PCAT1 knockdown significantly reduced the protein expression levels of anti‑apoptotic protein Bcl‑2, and significantly upregulated the protein expression levels of proapoptotic proteins, Bax, cleaved caspase‑3 and cleaved caspase‑9. Furthermore, the effect of a miR‑134‑3p inhibitor on BC progression was rescued by the knockdown of PITX2 in cells transfected with short hairpin RNA‑lncRNA PCAT1. To conclude, the results of the present study indicated that the PCAT1/miR‑134‑3p/PITX2 axis could be a promising therapeutic target in BC treatment.

Functional roles of lncRNAs in the pathogenesis and progression of cancer

Long noncoding RNAs (lncRNAs) act as regulators of gene expression and pivotal transcriptional regulators in cancer cells via diverse mechanisms. lncRNAs involves a variety of pathological and biological activities, such as apoptosis, cell proliferation, metastasis, and invasion. By using microarray and RNA sequencing, it was identified that dysregulation of lncRNAs affects the tumorigenesis process. Taken together, these lncRNAs are putative biomarker and therapeutic target in human malignancies. In this review, I discuss the latest finding regarding the dysregulation of some important lncRNAs and their diverse mechanisms of these lncRNAs in the pathogenesis and progression of certain cancers; also, I summarize the possible roles of lncRNAs in clinical application for diagnosis and prognosis of cancer.

Role of microRNA-129 in cancer and non-cancerous diseases (Review)

An increasing number of studies indicate that microRNAs (miRNAs/miRs) are involved in diverse biological signaling pathways and play important roles in the progression of various diseases, including both oncological and non-oncological diseases. These small non-coding RNAs can block translation, resulting in a low expression level of target genes. miR-129 is an miRNA that has been the focus of considerable research in recent years. A growing body of evidence shows that the miR-129 family not only functions in cancer, including osteosarcoma, nasopharyngeal carcinoma, and ovarian, prostate, lung, breast and colon cancer, but also in non-cancerous diseases, including heart failure (HF), epilepsy, Alzheimer's disease (AD), obesity, diabetes and intervertebral disc degeneration (IVDD). It is therefore necessary to summarize current research progress on the role of miR-129 in different diseases. The present review includes an updated summary of the mechanisms of the miR-129 family in oncological and non-oncological diseases. To the best of our knowledge, this is the first review focusing on the role of miR-129 in non-cancerous diseases such as obesity, HF, epilepsy, diabetes, IVDD and AD.

The value of long noncoding RNAs for predicting the recurrence of endometriosis: A protocol for meta-analysis and bioinformatics analysis

BACKGROUND

As a gynecological disease, endometriosis (EM) seriously endangers the health of women at the age of childbearing and is closely related to long noncoding RNAs (lncRNAs). Current studies have discovered that there are differential expressions of many kinds of lncRNAs in EM. However, whether lncRNAs can be applied as a new marker for the prediction of the recurrence of EM is still controversial. In this study, meta-analysis and bioinformatics analysis were carried out to explore the value of lncRNAs as a predictor of the recurrence of EM and to analyze its biological role.

METHODS

PubMed, Embase, and Web of Science databases were searched through computer and the articles published from the self-built database to April 2021 were collected. According to the inclusion and exclusion criteria, the literature was screened, and the quality of the inclusion study was evaluated. Stata 16.0 software was used for meta-analysis. The co-expression genes related to lncRNAs were screened by online tool Co-LncRNA. Then David for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis were conducted. A competitive endogenous RNA network that may exist in lncRNAs through Starbase was built.

RESULTS

The results of this meta-analysis would be submitted to peer-reviewed journals for publication.

CONCLUSION

This meta-analysis could provide high-quality evidence support for lncRNAs, so as to predict the recurrence of EM. At the same time, we use bioinformatics technology to predict and analyze its biological effects, which provides a theoretical basis for further experimental verification.

ETHICS AND DISSEMINATION

The private information from individuals will not be published. This systematic review also should not damage participants' rights. Ethical approval is not available. The results may be published in a peer-reviewed journal or disseminated in relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/MF3QJ.

The Impact of Long Non-Coding RNAs in the Pathogenesis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is among the utmost deadly human malignancies. This type of cancer has been associated with several environmental, viral, and lifestyle risk factors. Among the epigenetic factors which contribute in the pathogenesis of HCC is dysregulation of long non-coding RNAs (lncRNAs). These transcripts modulate expression of several tumor suppressor genes and oncogenes and alter the activity of cancer-related signaling axes. Several lncRNAs such as NEAT1, MALAT1, ANRIL, and SNHG1 have been up-regulated in HCC samples. On the other hand, a number of so-called tumor suppressor lncRNAs namely CASS2 and MEG3 are down-regulated in HCC. The interaction between lncRNAs and miRNAs regulate expression of a number of mRNA coding genes which are involved in the pathogenesis of HCC. H19/miR-15b/CDC42, H19/miR-326/TWIST1, NEAT1/miR-485/STAT3, MALAT1/miR-124-3p/Slug, MALAT1/miR-195/EGFR, MALAT1/miR-22/SNAI1, and ANRIL/miR-144/PBX3 axes are among functional axes in the pathobiology of HCC. Some genetic polymorphisms within non-coding regions of the genome have been associated with risk of HCC in certain populations. In the current paper, we describe the recent finding about the impact of lncRNAs in HCC.

PCAT-1 facilitates breast cancer progression via binding to RACK1 and enhancing oxygen-independent stability of HIF-1α

Hypoxia induces a series of cellular adaptive responses that enable promotion of inflammation and cancer development. Hypoxia-inducible factor-1α (HIF-1α) is involved in the hypoxia response and cancer promotion, and it accumulates in hypoxia and is degraded under normoxic conditions. Here we identify prostate cancer associated transcript-1 (PCAT-1) as a hypoxia-inducible long non-coding RNA (lncRNA) that regulates HIF-1α stability, crucial for cancer progression. Extensive analyses of clinical data indicate that PCAT-1 is elevated in breast cancer patients and is associated with pathological grade, tumor size, and poor clinical outcomes. Through gain- and loss-of-function experiments, we find that PCAT-1 promotes hypoxia-associated breast cancer progression including growth, migration, invasion, colony formation, and metabolic regulation. Mechanistically, PCAT-1 directly interacts with the receptor of activated protein C kinase-1 (RACK1) protein and prevents RACK1 from binding to HIF-1α, thus protecting HIF-1α from RACK1-induced oxygen-independent degradation. These findings provide new insight into lncRNA-mediated mechanisms for HIF-1α stability and suggest a novel role of PCAT-1 as a potential therapeutic target for breast cancer.

LncRNA PCAT1 Interacts with DKC1 to Regulate Proliferation, Invasion and Apoptosis in NSCLC Cells via the VEGF/AKT/Bcl2/Caspase9 Pathway

Long noncoding RNAs (lncRNAs) are increasingly recognized as indispensable components of the regulatory network in the progression of various cancers, including nonsmall cell lung cancer (NSCLC). The lncRNA prostate cancer associated transcript 1 (PCAT1) has been involved in tumorigenesis of multiple malignant solid tumors, but it is largely unknown that what is the role of lncRNA-PCAT1 and how it functions in the progression of lung cancer. Herein, we observed that lncRNA PCAT1 expression was upregulated in both human NSCLC tissues and cell lines, which was determined by qualitative polymerase chain reaction analysis. Then, gain-and loss-of-function manipulations were performed in A549 cells by transfection with a specific short interfering RNA against PCAT1 or a pcDNA-PCAT1 expression vector. The results showed that PCAT1 not only promoted NSCLC cell proliferation and invasion but also inhibited cell apoptosis. Bioinformatics and expression correlation analyses revealed that there was a potential interaction between PCAT1 and the dyskerin pseudouridine synthase 1 (DKC1) protein, an RNA-binding protein. Then, RNA pull-down assays with biotinylated probes and transcripts both confirmed that PCAT1 directly bounds with DKC1 that could also promote NSCLC cell proliferation and invasion and inhibit cell apoptosis. Moreover, the effects of PCAT1 and DKC1 on NSCLC functions are synergistic. Furthermore, PCAT1 and DKC1 activated the vascular endothelial growth factor (VEGF)/protein kinase B (AKT)/Bcl-2/caspase9 pathway in NSCLC cells, and inhibition of epidermal growth factor receptor, AKT, or Bcl-2 could eliminate the effect of PCAT1/DKC1 co-overexpression on NSCLC cell behaviors. In conclusion, lncRNA PCAT1 interacts with DKC1 to regulate proliferation, invasion, and apoptosis in NSCLC cells via the VEGF/AKT/Bcl-2/caspase9 pathway.

PCAT1: An oncogenic lncRNA in diverse cancers and a putative therapeutic target

The critical roles of long non-coding RNAs (lncRNAs) in the regulation of diverse biological functions has potentiated them as cancer biomarkers. Among these transcripts is the prostate cancer associated transcript 1 (PCAT1) which has been initially shown to exert oncogenic roles in prostate cancer. Further studies revealed its similar roles in various kinds of human malignancies including both solid tumors and hematological malignancies. Animal studies have shown that down-regulation of this lncRNA can attenuate tumor growth in a wide array of cancers including prostate cancer, colorectal cancer, squamous cell carcinoma lung cancer and hepatocellular carcinoma. Studies aimed at identification of diagnostic value of this lncRNA in human cancers reported various values ranging from 0.66 to 0.89 in diverse cancers with the best value reported in multiple myeloma. This lncRNA has a number of putative functional genomic variants such as rs1902432, rs2632159, rs1026411, rs710886, rs16901904 and rs710886 which can modify expression or function of PCAT1 thus altering the risk of human cancers. Based on aberrant expression of PCAT1 in malignancies of diverse origins, this lncRNA can be regarded as a therapeutic target in a vast array of cancers. Thus, modalities for efficient reduction of its expression would be beneficial for several patients.

Effect of CCT137690 on long non-coding RNA expression profiles in MCF-7 and MDA-MB-231 cell lines

Long non-coding RNAs (lncRNAs) are involved in a range of biological processes, such as cellular differentiation, migration, apoptosis, invasion, proliferation, and transcriptional regulation. The aberrant expression of lncRNAs plays a significant role in several cancer types. Aurora kinases are increasingly expressed in various malignancies; accordingly, the inhibition of these enzymes may represent a novel approach for the treatment of various cancers. CCT137690, an Aurora kinase inhibitor, displays an anti-proliferative activity in human cancer cell lines. The aim of the present study was to investigate the anti-proliferative and cytotoxic effects of CCT137690 on estrogen receptor (ER)-positive human breast cancer cell line (MCF-7) and ER-negative human breast cancer cell line (MDA-MB-231). In addition, this study was targeted toward determining the changes induced in lncRNA expression levels following the initiation of Aurora kinase inhibitor treatment. The cytotoxic effects of CCT137690 were determined by means of the xCELLigence system. Furthermore, the anti-proliferative role of CCT137690 in breast cancer was investigated by checking the changes in lncRNA expression profiles using quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The half-maximal inhibitory concentrations (IC₅₀) of CCT137690 were determined as 4.5 µM (MCF-7) and 7.27 µM (MDA-MB-231). Several oncogenic lncRNAs (e.g., PRINS, HOXA1AS, and NCRMS) were downregulated in both ER-negative and ER-positive cell lines. On the other hand, tumor suppressor lncRNAs (e.g., DGCR5 and IGF2AS) were upregulated in the ER-positive cell line. After CCT137690 treatment, HOXA11AS and PCAT-14 lncRNAs were downregulated in the ER-positive cell lines. In addition, MER11C, SCA8, BC200, HOTAIR, PCAT-1, UCA1, SOX2OT, and HULC lncRNAs were downregulated in the ER-negative cell lines. The results of the present study indicated that Aurora kinase inhibitor CCT137690 could be a potential anti-cancer agent for breast cancer treatment.

LncRNA PCAT1 activates AKT and NF-κB signaling in castration-resistant prostate cancer by regulating the PHLPP/FKBP51/IKKα complex

In PTEN-deficient prostate cancers, AKT signaling may be activated upon suppression of androgen receptor signaling. Activation of AKT as well as NF-κB signaling involves a key regulatory protein complex containing PHLPP, FKBP51 and IKKα. Here, we report a critical role of lncRNA PCAT1 in regulating the PHLPP/FKBP51/IKKα complex and progression of castration-resistant prostate cancer (CRPC). Using database queries, bioinformatic analyses, as well as RIP and RNA pull-down assays, we discovered and validated that the lncRNA-PCAT1 perturbs the PHLPP/FKBP51/IKKα complex and activates AKT and NF-κB signaling. Expression of lncRNA-PCAT1 is positively linked to CRPC progression. PCAT1 binds directly to FKBP51, displacing PHLPP from the PHLPP/FKBP51/IKKα complex, leading to activation of AKT and NF-κB signaling. Targeting PCAT1 restores PHLPP binding to FKBP1 leading to suppression of AKT signaling. Preclinical study in a mouse model of CRPC suggests therapeutic potential by targeting lncRNA PCAT1 to suppress CRPC progression. Together, the newly identified PCAT1/FKBP51/IKKα complex provides mechanistic insight in the interplay between AKT, NF-κB and AR signaling in CRPC, and the preclinical studies suggest that a novel role for PCAT1 as a therapeutic target.

Long noncoding RNAs in cancer: From discovery to therapeutic targets

Long noncoding RNAs (lncRNAs) have recently gained considerable attention as key players in biological regulation; however, the mechanisms by which lncRNAs govern various disease processes remain mysterious and are just beginning to be understood. The ease of next-generation sequencing technologies has led to an explosion of genomic information, especially for the lncRNA class of noncoding RNAs. LncRNAs exhibit the characteristics of mRNAs, such as polyadenylation, 5' methyl capping, RNA polymerase II-dependent transcription, and splicing. These transcripts comprise more than 200 nucleotides (nt) and are not translated into proteins. Directed interrogation of annotated lncRNAs from RNA-Seq datasets has revealed dramatic differences in their expression, largely driven by alterations in transcription, the cell cycle, and RNA metabolism. The fact that lncRNAs are expressed cell- and tissue-specifically makes them excellent biomarkers for ongoing biological events. Notably, lncRNAs are differentially expressed in several cancers and show a distinct association with clinical outcomes. Novel methods and strategies are being developed to study lncRNA function and will provide researchers with the tools and opportunities to develop lncRNA-based therapeutics for cancer.

Polymorphisms in Long Noncoding RNA-Prostate Cancer-Associated Transcript 1 Are Associated with Lung Cancer Susceptibility in a Northeastern Chinese Population

Long noncoding RNAs (lncRNAs) are a new class of potential biomarkers and therapeutic targets for cancer. In this study, we chose four single nucleotide polymorphisms (SNPs) in lncRNA-PCAT1 (rs1026411 G>A, rs12543663 A>C, rs710886 T>C, and rs16901904 T>C) to investigate the association between genetic variant in lncRNA-PCAT1 and susceptibility to lung cancer. The study was a hospital-based case–control study including 561 cancer-free controls and 468 lung cancer cases. Genotyping of four SNPs was conducted by using Taqman^® allelic discrimination methods. All statistical analyses were performed by using IBM SPSS Statistics 22 software. We failed to find significant associations between four SNPs and lung cancer risk in all models. However, polymorphisms in rs1026411 and rs710886 were observed to have significant associations with susceptibility to non-small cell lung cancer (AG vs. GG: odds ratio [OR]^a = 0.701, p* = 0.020 and AA+AG vs. GG: OR^a = 0.711 [superscript “a” refers to OR adjusted by age, gender, and smoking], p* = 0.017 [asterisks “*” refers to p adjusted by age, gender, and smoking] for rs1026411; CT vs. TT: OR^a = 0.723, p* = 0.047 and CC+CT vs. TT: OR^a = 0.729, p* = 0.038 for rs710886). Besides, the rs1026411 polymorphism had a similar association with lung adenocarcinoma risk (AG vs. GG: OR^a = 0.663, p* = 0.019 and AA+AG vs. GG: OR^a = 0.685, p* = 0.020). Polymorphisms in rs710886 and rs16901904 were observed to be associated with lung squamous cell carcinoma risk (CC+CT vs. TT: OR^a = 0.638, p* = 0.040 for rs710886; CC vs. TT: OR^a = 2.582, p* = 0.033 and CC vs. TT+CT: OR^a = 2.381, p* = 0.048 for rs16901904). In addition, there were no significant results in gene–environmental interactions in both additive and multiplicative models. Our results suggested that polymorphisms in lncRNA-PCAT1 might be associated with lung cancer susceptibility in a northeastern Chinese population. The results of gene–environmental interactions were not significant in lung cancer.

PCAT1 is a poor prognostic factor in endometrial carcinoma and associated with cancer cell proliferation, migration and invasion

Long non-coding RNAs (lncRNAs) are emerging as important modulators of cancer progression, among which prostate cancer-associated transcript 1 (PCAT1) has been shown to be an oncogene in several tumors. However, the clinical significance and biological function of PCAT1 in endometrial carcinoma (EC) remain unclear. In this study, we used 89 EC tissues and HEC-1B, Ishikawa, RL95-2 and AN3CA EC cell lines. We found elevated expression levels of PCAT1 in EC tissues and cell lines using reverse transcription qPCR (RT-qPCR). The prognostic value of PCAT1 was determined using Kaplan-Meier survival and Cox regression analysis. The results showed that higher PCAT1 expression was positively correlated with FIGO stage, myometrial invasion, lymph node metastasis, and a shorter overall survival. A series of functional assays showed that the knockdown of PCAT1 by small interfering RNA (siRNA) targeting PCAT1 (siPCAT1) suppressed cell proliferation, migration and invasion, but promoted apoptosis. Western blot analysis further showed that B-cell lymphoma 2 (Bcl-2), vimentin and N-cadherin were downregulated, but E-cadherin and Bcl-2-associated death promoter (Bad) were upregulated in PCAT1-silenced EC cells. Taken together, our results underscore the oncogenic role of PCAT1 in EC and show that PCAT1 may be a potential therapeutic target in EC treatment.

Long noncoding RNA PCAT1, a novel serum-based biomarker, enhances cell growth by sponging miR-326 in oesophageal squamous cell carcinoma

Long noncoding RNAs (lncRNAs) play important roles in the development and progression of human cancers. The lncRNA prostate cancer-associated transcript 1 (PCAT1) has been reported to be involved in multiple human cancers, including oesophageal squamous cell carcinoma (ESCC). However, the detailed biological functions, underlying mechanisms and clinical relevance of PCAT1 in ESCC remain unclear. Here, we confirmed that PCAT1 was highly expressed in ESCC tissues and cell lines. Knockdown of PCAT1 inhibited the growth of ESCC cells, whereas overexpression of PCAT1 showed the opposite effect both in vitro and in vivo. Moreover, knockdown of PCAT1 arrested the cell cycle at G2/M phase, reduced the expression of cyclin B1 and CDC2, and caused cells to be more sensitive to paclitaxel. Furthermore, PCAT1 could bind to miR-326, a tumour suppressor in diverse human cancers. Rescue experiments revealed that enforced expression of miR-326 attenuated the promotive effect of PCAT1 on ESCC cell growth. In addition, we discovered that PCAT1 was present in ESCC cell-derived exosomes, was higher in the serum of ESCC patients than those of healthy volunteer donors, and promoted cell growth through exosomes. Thus, our data indicate that PCAT1 promotes ESCC cell proliferation by sponging miR-326 and may serve as a non-invasive biomarker for ESCC.

LncRNAs with miRNAs in regulation of gastric, liver, and colorectal cancers: updates in recent years

Long noncoding RNA (lncRNA) is a kind of RNAi molecule composed of hundreds to thousands of nucleotides. There are several major types of functional lncRNAs which participate in some important cellular pathways. LncRNA-RNA interaction controls mRNA translation and degradation or serves as a microRNA (miRNA) sponge for silencing. LncRNA-protein interaction regulates protein activity in transcriptional activation and silencing. LncRNA guide, decoy, and scaffold regulate transcription regulators of enhancer or repressor region of the coding genes for alteration of expression. LncRNA plays a role in cellular responses including the following activities: regulation of chromatin structural modification and gene expression for epigenetic and cell function control, promotion of hematopoiesis and maturation of immunity, cell programming in stem cell and somatic cell development, modulation of pathogen infection, switching glycolysis and lipid metabolism, and initiation of autoimmune diseases. LncRNA, together with miRNA, are considered the critical elements in cancer development. It has been demonstrated that tumorigenesis could be driven by homeostatic imbalance of lncRNA/miRNA/cancer regulatory factors resulting in biochemical and physiological alterations inside the cells. Cancer-driven lncRNAs with other cellular RNAs, epigenetic modulators, or protein effectors may change gene expression level and affect the viability, immortality, and motility of the cells that facilitate cancer cell cycle rearrangement, angiogenesis, proliferation, and metastasis. Molecular medicine will be the future trend for development. LncRNA/miRNA could be one of the potential candidates in this category. Continuous studies in lncRNA functional discrepancy between cancer cells and normal cells and regional and rational genetic differences of lncRNA profiles are critical for clinical research which is beneficial for clinical practice.

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 PCAT-1 promotes tumor progression by inhibiting miR-129-5p in human ovarian cancer

INTRODUCTION

Ovarian cancer (OC) is one of the most common malignancies and the leading cause of cancer-related death among women. The long non-coding RNA Prostate cancer-associated transcript-1 (PCAT-1) has been reported to play important roles in multiple human cancers. However, the role of PCAT-1 in OC has never been investigated. The purpose of this study was to investigate the expression and roles of PCAT-1 in OC.

MATERIAL AND METHODS

Expression of PCAT-1 and miR-129-5p in OC tissues and cell lines was determined by qRT-PCR. Cell proliferation and apoptosis were analyzed by MTT assay and flow cytometry, respectively. The interaction between PCAT-1 and miR-129-5p was demonstrated by luciferase reporter assay.

RESULTS

PCAT-1 is significantly upregulated in OC tissues and cell lines (p < 0.05). Overexpression of PCAT-1 promotes proliferation of OC cells and inhibits their apoptosis (p < 0.05). In addition, miR-129-5p is markedly downregulated in OC and its level is inversely correlated with PCAT-1 expression in OC tumor tissues (p < 0.05). miR-129-5p inhibits proliferation and induces apoptosis in OC cell lines (p < 0.05). Furthermore, it has been demonstrated that miR-129-5p is directly targeted by PCAT-1 and miR-129-5p overexpression can effectively attenuate the effects of PCAT-1 on the proliferation and apoptosis of OC cells.

CONCLUSIONS

Our results suggest that PCAT-1 functions as an oncogene by inhibiting miR-129-5p in OC and silencing PCAT-1 may be a novel therapeutic strategy in the treatment of OC.

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.

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.

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.

Down-regulation of long non-coding RNA GAS5-AS1 and its prognostic and diagnostic significance in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common solid tumor in global range, with high degree of malignancy and poor prognosis. But the relationship between the expression of GAS5-AS1 and HCC is not documented. This study aimed to profile GAS5-AS1 expression signature and then to explore its clinical significance in HCC.

METHODS

Quantitative real-time PCR (RT-qPCR) was performed to detect the expression of GAS5-AS1 in 83 pairs of HCC surgical tissues and adjacent normal liver tissues. We also performed RT-qPCR on plasma samples of 156 patients and 58 healthy controls.

RESULTS

We found that GAS5-AS1 was down-regulated in HCC tissues (P< 0.01). Correlation analysis showed that the expression of GAS5-AS1 was notably associated with differentiation (High/Moderate vs Low, P= 0.031), tumor-node-metastasis (TNM) stage (I∼II vs III∼IV, P= 0.020) and glucose levels (< 6.2 vs≧ 6.2, P= 0.047) in HCC patients. The overall survival analysis showed that patients with lower GAS5-AS1 expression had a relatively poor prognosis. Univariate and multivariate analysis elaborated that GAS5-AS1 was an independent prognostic factor for HCC patients. The area under the ROC (AUCROC) demonstrated that GAS5-AS1 presented a high accuracy (AUC = 0.824, 95% CI: 0.741-0.906) for distinguishing HCC from the cirrhosis. When differentiating HCC cases with AFP < 200 ng/ml from the cirrhosis and hepatitis B whose AFP levels were also below 200 ng/ml, GAS5-AS1 had the high sensitivity (89.5%, 89.5%, respectively).

CONCLUSIONS

GAS5-AS1 could be considered as a potential prognostic and diagnostic marker in HCC. However, the potential clinical application value of GAS5-AS1 still needs to be further illustrated.

Enhanced expression of the long non-coding RNA SNHG16 contributes to gastric cancer progression and metastasis

This paper aimed to probe into the expression of long non-coding RNA (lncRNA) SNHG16 in human gastric cancer (GC) and its potential tumor biological functions. The expression of lncRNA SNHG16 was detected in GC and adjacent tissues and GC cell lines using qRT-PCR. GC MGC-803 cells were transfected with siRNA of lncRNA SNHG16, as well as blank and negative control. A series of experiments including CCK-8, flow cytometry, transwell, and wound healing assay were adopted to evaluate the effects of lncRNA SNHG16 on cell growth and metastasis. Besides, the nude mouse xenograft tumor model was established to draw tumor growth curve and measure tumor volume during treatments. TUNEL staining was used to determine the apoptosis rate of tissues. The expression of lncRNA SNHG16 in GC tissue, significantly associated with invasion depth, lymph node metastasis, TNM stage and histological differentiation (all P< 0.05), was upregulated compared with adjacent tissues. Transfected with siRNA of lncRNA SNHG16 inhibited GC MGC-803 cell proliferation, and arrested cells in the G0/G1 phase, and then promoted apoptosis rate with reduced cell invasion and shortened migration distance. Additionally, the nude mice xenograft presented lower tumor growth rate and weight loss alongside elevated apoptosis rate of tumor tissues. LncRNA SNHG16 is highly expressed in GC, while suppression of SNHG16 expression can inhibit proliferation, weaken invasion and migration of GC cells, and enhance apoptosis, to be a novel target for GC clinical treatment.

SIK1-LNC represses the proliferative, migrative, and invasive abilities of lung cancer cells

Background

Discussions regarding the correlations between long non-coding RNAs (lncRNAs) and cancers have dominated research in recent years. SIK1-LNC, a type of lncRNA and adjacent to salt-inducible kinases 1 (SIK1), has been found aberrantly expressed in lung cancer. However, its functional role in lung cancer remains largely unknown.

Purpose

In this study, we aimed to explore the association between SIK1-LNC expression and SIK1 in lung cancer cells and further identify the impact of SIK1-LNC on the proliferation, migration invasion of lung cancer cells.

Patients and methods

Of the 30 patients with non-small-cell lung carcinoma from Zhongnan Hospital of Wuhan University, RT-qPCR was performed to detect SIK1 and SIK1-LNC expressions in patients’ samples. Overexpression and knockdown experiments were conducted to analyze the SIK1 and SIK1-LNC expressions in lung cancer cell lines. CCK-8, Brdu, scratch wound-healing, and Transwell assays were respectively employed to evaluate the proliferative, migrative, and invasive abilities of lung cancer cells.

Results

Both SIK1-LNC and SIK1 expression levels were evidently downregulated in 30 lung cancer tissues. SIK1-LNC expression was bound up with clinicopathologic features, including lymph node metastasis and distant metastasis. SIK1 expression showed a positive tendency with SIK1-LNC expression in lung cancer cells. SIK1-LNC exerted a significant repression on cell proliferatiive, miogrative and invasive abilities of lung cancer cells.

Conclusion

Our findings suggested that SIK1-LNC may act as a novel biomarker and therapeutic target for lung cancer.

The emergence of long non-coding RNAs in hepatocellular carcinoma: an update

Hepatocellular carcinoma (HCC) accounting for roughly 90% of all primary liver neoplasms is the sixth most frequent neoplasm and the second prominent reason of tumor fatality worldwide. As regulators of diverse biological processes, long non-coding RNAs (lncRNAs) are involved in onset and development of neoplasms. With the continuous booming of well-featured lncRNAs in HCC from 2016 to now, we reviewed the newly-presented comprehension about the relationship between lncRNAs and HCC in this study. To be specific, we summarized the overview function and study tools of lncRNAs, elaborated the roles of lncRNAs in HCC, and sketched the molecule mechanisms of lncRNAs in HCC. In addition, the application of lncRNAs serving as biomarkers in early diagnosis and outcome prediction of HCC patients was highlighted.

LncRNA PCAT1 and its genetic variant rs1902432 are associated with prostate cancer risk

Emerging evidence has showed that lncRNAs and trait-associated loci in lncRNAs play a crucial role in the progression of cancer including prostate cancer (PCa).This study aimed to investigate the molecular mechanisms of lncRNA PCAT1 involved in PCa development and its genetic variant associated with PCa risk. We applied cell proliferation and apoptosis assays to assess the effect of PCAT1 on PCa cell phenotypes. In addition, the genome-wide profiling of gene expression was assessed from three pairs of DU145 cells transfected with PCAT1 overexpression vector or negative control (NC) vector. Furthermore, a case-control study was conducted to explore the associations of four tagging single nucleotide polymorphisms (tagSNPs) and PCa risk in 850 PCa cases and 860 cancer-free controls. Our results showed that lncRNA PCAT1 promoted cell proliferation and inhibited cell apoptosis. Ingenuity pathway analysis (IPA) indicated that dysregulated mRNAs induced by overexpression of PCAT1 were primarily enriched in androgen-independent prostate tumor term and implicated in the disease and functions networks, such as cell death and survival, cell proliferation and gene expression. Besides, rs1902432 in PCAT1 was significantly associated with increased risk of PCa (Additive model: OR = 1.19, P = 0.014; Co-dominant model: CC vs. TT, OR = 1.45, P =0.012; Recessive model: CC vs. TT/CT, OR= 1.34, P = 0.027). This study suggests that PCAT1 may act as an oncogene through promoting cell proliferation and suppressing cell apoptosis in PCa development, and genetic variant in PCAT1 contributes to the susceptibility to PCa.

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.

Prostate cancer susceptibility and growth linked to Y chromosome genes

The role of Y chromosome in prostate cancer progression and incidence is not well known. Among the 46 chromosomes, Y chromosome determines the male gender. The Y chromosome is smaller than the X chromosome and contains only 458 genes compared to over 2000 genes found in the X chromosome. The Y chromosome is prone to high mutation rates, created exclusively in sperm cells due to the highly oxidative environment of the testis. Y chromosome harbors epigenetic information, which affects the expression of genes associated with the incidence and progression of prostate cancer. In this review, we focus on Y chromosome related genetic abnormalities, likely to be involved in the development and progression of prostate cancer.

The Role of Long Non-Coding RNAs in Hepatocarcinogenesis

Whole-transcriptome analyses have revealed that a large proportion of the human genome is transcribed in non-protein-coding transcripts, designated as long non-coding RNAs (lncRNAs). Rather than being “transcriptional noise”, increasing evidence indicates that lncRNAs are key players in the regulation of many biological processes, including transcription, post-translational modification and inhibition and chromatin remodeling. Indeed, lncRNAs are widely dysregulated in human cancers, including hepatocellular carcinoma (HCC). Functional studies are beginning to provide insights into the role of oncogenic and tumor suppressive lncRNAs in the regulation of cell proliferation and motility, as well as oncogenic and metastatic potential in HCC. A better understanding of the molecular mechanisms and the complex network of interactions in which lncRNAs are involved could reveal novel diagnostic and prognostic biomarkers. Crucially, it may provide novel therapeutic opportunities to add to the currently limited number of therapeutic options for HCC patients. In this review, we summarize the current status of the field, with a focus on the best characterized dysregulated lncRNAs in HCC.

Behind the curtain of non-coding RNAs; long non-coding RNAs regulating hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is one of the most common and aggressive cancers worldwide. HCC is the fifth common malignancy in the world and the second leading cause of cancer death in Asia. Long non-coding RNAs (lncRNAs) are RNAs with a length greater than 200 nucleotides that do not encode proteins. lncRNAs can regulate gene expression and protein synthesis in several ways by interacting with DNA, RNA and proteins in a sequence specific manner. They could regulate cellular and developmental processes through either gene inhibition or gene activation. Many studies have shown that dysregulation of lncRNAs is related to many human diseases such as cardiovascular diseases, genetic disorders, neurological diseases, immune mediated disorders and cancers. However, the study of lncRNAs is challenging as they are poorly conserved between species, their expression levels aren’t as high as that of mRNAs and have great interpatient variations. The study of lncRNAs expression in cancers have been a breakthrough as it unveils potential biomarkers and drug targets for cancer therapy and helps understand the mechanism of pathogenesis. This review discusses many long non-coding RNAs and their contribution in HCC, their role in development, metastasis, and prognosis of HCC and how to regulate and target these lncRNAs as a therapeutic tool in HCC treatment in the future.

Differential long non-coding RNA expression profiles in human oocytes and cumulus cells

Progress in assisted reproductive technologies strongly relies on understanding the regulation of the dialogue between oocyte and cumulus cells (CCs). Little is known about the role of long non-coding RNAs (lncRNAs) in the human cumulus-oocyte complex (COC). To this aim, publicly available RNA-sequencing data were analyzed to identify lncRNAs that were abundant in metaphase II (MII) oocytes (BCAR4, C3orf56, TUNAR, OOEP-AS1, CASC18, and LINC01118) and CCs (NEAT1, MALAT1, ANXA2P2, MEG3, IL6STP1, and VIM-AS1). These data were validated by RT-qPCR analysis using independent oocytes and CC samples. The functions of the identified lncRNAs were then predicted by constructing lncRNA-mRNA co-expression networks. This analysis suggested that MII oocyte lncRNAs could be involved in chromatin remodeling, cell pluripotency and in driving early embryonic development. CC lncRNAs were co-expressed with genes involved in apoptosis and extracellular matrix-related functions. A bioinformatic analysis of RNA-sequencing data to identify CC lncRNAs that are affected by maternal age showed that lncRNAs with age-related altered expression in CCs are essential for oocyte growth. This comprehensive analysis of lncRNAs expressed in human MII oocytes and CCs could provide biomarkers of oocyte quality for the development of non-invasive tests to identify embryos with high developmental potential.

The lncRNA PCAT1 is correlated with poor prognosis and promotes cell proliferation, invasion, migration and EMT in osteosarcoma

Introduction

Osteosarcoma is a malignant primary bone cancer and is lethal to children and adolescents. Recently, the dysregulation of long noncoding RNAs (lncRNAs) has been shown in various types of cancers.

Aim

The present study aimed to examine the role of the lncRNA prostate cancer-associated transcript 1 (PCAT1) in osteosarcoma progression.

Materials and methods

The expression levels of relevant genes in clinical samples and cell lines were determined by quantitative real-time polymerase chain reaction. Cell proliferation, invasion and migration were examined by CCK-8 assay, transwell invasion and migration assay, respectively. Cell apoptosis and cell cycle were detected by flow cytometry. Protein levels were detected by Western blot.

Results

Our results showed that PCAT1 was upregulated in osteosarcoma tissues when compared to normal bone tissues. PCAT1 was also upregulated in osteosarcoma cell lines when compared to normal bone cell line. The upregulation of PCAT1 was significantly associated with advanced clinical stage, tumor metastasis and shorter overall survival in patients with osteosarcoma. In vitro studies showed that overexpression of PCAT1 in MG-63 cells enhanced cell proliferation, cell invasion and migration and epithelial-to-mesenchymal transition (EMT); decreased cell apoptotic rate; and also caused an increase in cell population at S phase with a decrease in cell population at G₀/G₁ phase. Knockdown of PCAT1 in U2OS cells suppressed cell proliferation, cell invasion and migration, and EMT; increased cell apoptotic rate; and caused an increase in the cell population at G₀/G₁ phase with a decrease in cell population at S phase.

Conclusion

Taken together, our results suggest the oncogenic role of PCAT1 in osteosarcoma progression.

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.

MiR-320d suppresses the progression of breast cancervialncRNA HNF1A-AS1 regulation and SOX4 inhibition

MicroRNA-320d (miR-320d) is a novel cancer-related miRNA and functions as a tumor suppressor in human cancers.

Long noncoding RNAs in the initiation, progression, and metastasis of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. Despite awareness of risk factors for the development of HCC and advances in the diagnosis and clinical management of the disease, the molecular mechanisms underlying hepatocarcinogenesis remain poorly understood. Recent experimental studies provide strong evidence that long noncoding RNAs (lncRNAs), non-protein-coding transcripts with lengths >200 basepairs, contribute to the pathogenesis of numerous human diseases. Over the past decade, a role for lncRNAs in the initiation, progression, and metastasis of HCC has likewise emerged and developed into a highly active area of research. Although many lncRNAs appear to be dysregulated in HCC, extensive functional characterization has been performed on only a small proportion of these candidates to date. This review summarizes select lncRNAs that have been shown to wield functional relevance in the initiation, progression, or metastasis of HCC, focusing on the specific mechanisms by which lncRNA effects might be linked to clinical manifestations of the disease. In addition, an overview of circulating lncRNAs that have been identified as potential biomarkers for the diagnosis and prognosis of HCC is provided.

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.

The long noncoding RNA PCAT-1 links the microRNA miR-215 to oncogene CRKL-mediated signaling in hepatocellular carcinoma

The long non-coding RNA (lncRNA) PCAT-1 resides in the chromosome 8q24 cancer-risk locus and acts as a vital oncogene during tumorigenesis and progression. However, how PCAT-1 is post-transcriptionally regulated, for example, by small ncRNAs, such as microRNAs (miRNAs) is largely unknown. Here, we report how miRNAs regulate PCAT-1 expression and also investigate the biological significance of this regulation in hepatocellular carcinoma (HCC). We found that miR-215, a P53-inducible miRNA, is a key regulator of PCAT-1 expression in HCC and identified an interaction between miR-215 and PCAT-1 in dual luciferase reporter gene assays. We also found that post-transcriptional silencing of PCAT-1 by miR-215 or PCAT-1 siRNAs significantly inhibited proliferation of HCC cells and, conversely, that inhibition of endogenous miR-215 up-regulated PCAT-1 expression and promoted cell viability. The tumor-suppressing role of miR-215 was further confirmed in an in vivo mouse HCC xenograft model. Of note, gene profiling assays suggested that the kinase CRK-like proto-oncogene, adaptor protein (CRKL), is a potential downstream target of the miR-215-PCAT-1 axis in HCC, and we demonstrated that CRKL silencing significantly suppresses cell proliferation. Taken together and considering the essential role of CRKL in cancer cells, we propose that the TP53-miR-215-PCAT-1-CRKL axis might represent an important regulatory pathway in HCC. In summary, our results highlight the involvement of several ncRNAs in HCC and thus provide critical insights into the molecular pathways operating in this malignancy.

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.

The association of rs710886 in lncRNA PCAT1 with bladder cancer risk in a Chinese population

OBJECTIVE

The long noncoding RNA PCAT1 is an important gene involved in urinary tumors. In this study, we aimed to explore the association between polymorphisms in PCAT1 and bladder cancer susceptibility.

METHODS

A two-stage case-control study was conducted to assess the association between four tagging SNPs (i.e., rs4871771, rs1902432, rs16901904 and rs710886) and bladder cancer risk. Odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated with unconditional univariate and multivariate logistic regression.

RESULTS

At the first stage of discovery, we identified that SNP rs710886A>G was significantly associated with bladder cancer risk (OR=0.86, 95% CI=0.74-0.99, P=0.046). At the following stage of validation, individuals with GG genotype were found to have a significant reduction in bladder cancer risk compared with those carrying AA genotype (adjusted OR=0.83, 95% CI=0.74-0.93, P=0.001). Furthermore, stratified analyses showed that protective effect of rs710886 was more pronounced in subgroup of age>60 and never smoking, and had little to do with sex. Besides, rs710886 was identified as an eQTL for PCAT1. G allele was consistent with lower PCAT1 expression.

CONCLUSION

This study indicates that genetic variants in lncRNA PCAT1 were associated with bladder cancer susceptibility and the SNP rs710886 may act as a potential biomarker for bladder cancer risk.

Long Non-coding RNAs and their Role in Metastasis

The perception of long non-coding RNAs as chunk RNA and transcriptional noise has been steadily replaced by their role as validated targets for a diverse set of physiological processes in the past few years. However, for the vast majority of lncRNAs their precise mode of action and physiological function remain to be uncovered. A large body of evidence has revealed their essential role in all stages of cancirogenesis and metastasis. In this review we focus on the role of lncRNAs in metastasis. We grouped selected lncRNAs into three categories based on in vitro and in vivo mode of action-related studies and clinical relevance for metastasis. Grouped according to their mode of action, in category I we discuss lncRNAs such as CCAT2, DREH, LET, NKILA, treRNA, HOTAIR, H19, FENDRR, lincROR, MALAT, GClnc1, BCAR4, SCHLAP1 and lncRNA ATP, all lncRNAs with in vitro and in vivo metastasis-related data and clinical significance. In category II we discuss lncRNAs CCAT1, PCAT1, PTENgp1, GPLINC, MEG3, ZEB2-AS, LCT13, ANRIL, NBAT1 and lncTCF7 all characterized by their mode of action in vitro and clinical significance, but pending or preliminary in vivo data. Finally, under category III, we discuss lncRNAs BANCR, FRLnc1, SPRY4-IT1 and LIMT with partially or poorly-resolved mode of action and varying degree of validation in clinical metastasis. Finally we discuss metastasis-related translational aspects of lncRNAs.

Up-regulation of LINC00161 correlates with tumor migration and invasion and poor prognosis of patients with hepatocellular carcinoma

Accumulating evidence suggested that long non-coding RNAs (lncRNAs) play essential roles in various biological processes, including tumorigenesis. Aberrant expression of LINC00161 has been reported in some cancer types, however, the association of LINC00161 and hepatocellular carcinoma (HCC) has not been evaluated. Here, we measured the expression of LINC00161 in HCC tissues and corresponding normal liver tissues using real-time PCR. The result showed that the expression level of LINC00161 was significantly higher in HCC tissues. Further analysis indicated that HCC patients with higher LINC00161 expression have shorter survival. Multivariate Cox regression analysis showed that LINC00161 expression was an independent prognostic factor for the overall survival. Furthermore, our result indicated that knock-down of LINC00161 can significantly inhibit liver cancer cell migration and invasion. The present work indicated that LINC00161 might serve as an oncogenic gene and play a pivotal role in promoting tumor migration and invasion in HCC. Our work implicates the promising effect of LINC00161 on the prognosis of HCC.