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

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.

Targeting lncRNAs of colorectal cancers with natural products

Non-coding RNA (ncRNA) is one of the functional classes of RNA that has a regulatory role in various cellular processes, such as modulation of disease onset, progression, and prognosis. ncRNAs, such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), have been actively studied in recent years. The change in ncRNA levels is being actively studied in numerous human diseases, especially auto-immune disorders and cancers; however, targeting and regulating ncRNA with natural products to cure cancer has not been fully established. Recently many groups reported the relationship between ncRNA and natural products showing promising effects to serve as additional therapeutic approaches to cure cancers. This mini-review summarizes the aspects of lncRNAs related to cancer biology focusing on colorectal cancers that natural products can target.

Apoptosis evasion via long non-coding RNAs in colorectal cancer

Long non-coding RNA (LncRNA) is a novel and diverse class of regulatory transcripts that are frequently dysregulated in numerous tumor types. LncRNAs are involved in a complicated molecular network, regulating gene expression, and modulating diverse cellular activities in different cancers including colorectal cancer (CRC). Evidence indicates that lncRNAs can be used as a potential biomarker for the prognosis and diagnosis of CRC as they are aberrantly expressed in CRC cells. The high expression or silencing of lncRNAs is associated with cell proliferation, invasion, metastasis, chemoresistance and apoptosis in CRC. LncRNAs exert both pro-apoptotic and anti-apoptotic functions in CRC. The expression of some oncogene lncRNAs is upregulated which leads to the inhibition of apoptotic pathways, similarly, the tumor suppressor lncRNAs are downregulated in CRC. In this review, we describe the function and mechanisms of lncRNAs to regulate the expression of genes that are involved directly or indirectly in controlling cellular apoptosis in CRC. Furthermore, we also discussed the different apoptotic pathways in normal cells and the mechanisms by which CRC evade apoptosis.

Whole-genome-scale identification of novel non-protein-coding RNAs controlling cell proliferation and survival through a functional forward genetics strategy

Identification of cell fate-controlling lncRNAs is essential to our understanding of molecular cell biology. Here we present a human genome-scale forward-genetics approach for the identification of lncRNAs based on gene function. This approach can identify genes that play a causal role, and immediately distinguish them from those that are differentially expressed but do not affect cell function. Our genome-scale library plus next-generation-sequencing and bioinformatic approach, radically upscales the breadth and rate of functional ncRNA discovery. Human gDNA was digested to produce a lentiviral expression library containing inserts in both sense and anti-sense orientation. The library was used to transduce human Jurkat T-leukaemic cells. Cell populations were selected using continuous culture ± anti-FAS IgM, and sequencing used to identify sequences controlling cell proliferation. This strategy resulted in the identification of thousands of new sequences based solely on their function including many ncRNAs previously identified as being able to modulate cell survival or to act as key cancer regulators such as AC084816.1*, AC097103.2, AC087473.1, CASC15*, DLEU1*, ENTPD1-AS1*, HULC*, MIRLET7BHG*, PCAT-1, SChLAP1, and TP53TG1. Independent validation confirmed 4 out of 5 sequences that were identified by this strategy, conferred a striking resistance to anti-FAS IgM-induced apoptosis.

Combination of resveratrol and BIBR1532 inhibits proliferation of colon cancer cells by repressing expression of LncRNAs

Colorectal cancer (CRC) is the third most common cancer worldwide. The development of tumor drug resistance is observed in the treatment of CRC. Combinations of anticancer agents are attracting considerable interest in order to overcome drug resistance in CRC. This study aims to investigate the effect of resveratrol and BIBR1532, either alone or in combination, on the cell viability as well as on expression of long non-coding RNAs (LncRNAs) for HT-29 colon adenocarcinoma cells. The cytotoxic effects of resveratrol and BIBR1532 on HT-29 cells were determined using WST-1 test. Flow cytometry was used to determine apoptotic cell death after treatments. Real-Time PCR was used to identify expression of LncRNAs after treatments. LncExpDB and GEPIA2 were used to evaluate expression profiles of LncRNAs, whose expression levels were decreased in HT-29 cells after treatments, in normal tissues and colon adenocarcinoma tumors. IC₅₀ concentrations of BIBR1532 and resveratrol were found to be 50.81 μM at 48 h and 86.23 μM at 72 h, respectively. Combination index value was 1.07617. BIBR1532, resveratrol, or their combination reduced the cell viability of HT-29 cells. CCAT1, CRNDE, HOTAIR, PCAT1, PVT1, SNHG16 were down-regulated after treatments. In silico analysis revealed that LncRNAs whose expression levels were decreased after treatments were associated with CRC. Resveratrol, BIBR1532, or their combination may have anti-proliferative effect on colorectal cancer cells through repressing expression of LncRNAs that are involved in progression of CRC.

Long Non-Coding RNA OIP5-AS1 Inhibits the Proliferation and Migration of Esophageal Squamous Carcinoma Cells by Targeting FOXD1/miR-30a-5p Axis and the Effect of Micro- and Nano-Particles on Targeting Transfection System

Esophageal cancer is one of the most common human malignancies and ranks sixth for global mortality; the major histological type is esophageal squamous cell carcinoma (ESCC). Here we assessed the effect of long non-coding (lnc) RNA OIP5-AS1 on the miR-30a-5p/Forkhead box protein D1 (FOXD1) axis in ESCC and investigated the underlying mechanism involving the ERK1/2 signaling pathway. lnc RNA OIP5-AS1 was highly expressed in human ESCC tissues and cells, targeted miR-30a-5p, and inhibited miR-30a-5p expression. Additionally, in human ESCC tissues, miR-30a-5p was poorly expressed, whereas FOXD1 mRNA and protein were highly expressed, with a negative correlation between miR-30a-5p and FOXD1 expression. miR-30a-5p targeted and inhibited FOXD1 expression. FOXD1 promoted the proliferation and invasion of ESCC and was related to the ERK1/2 signaling pathway; ERK1/2 inhibitors (LY-3214996) reversed the biological function of FOXD1. miR-30a-5p combined with FOXD1 regulated ERK1/2 expression and inhibited tumor growth in vivo. In this study, micro- and nano-particles were used as carriers to construct Nanocapsules carrying miR-30a-5p mimics and miR-30a-5p inhibitor through self-assembly method, so as to realize an efficient Nanocapsules delivery system of miR-30a-5p to esophageal cancer cells. It provides insights into targeted drug therapy and the development of micro- and nano-particles carriers.

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.

Long non-coding RNA PCAT-1 regulates apoptosis of chondrocytes in osteoarthritis by sponging miR-27b-3p

BACKGROUND

Osteoarthritis (OA) is a non-inflammatory degenerative disease, with progressive damages on the articular cartilages. In recent years, researchers have paid many efforts in the diagnostics and treatments of OA. However, no effective therapeutic method has been revealed to help inhibit the development of OA. Herein, we studied the roles and associations of PCAT-1 and miR-27-3p in the pathogenesis OA.

METHODS

OA articular cartilages and healthy articular cartilages were isolated for investigation. The chondrocytes were isolated from articular cartilage samples. QRT-PCR and western blotting were used for the detection of expression of genes and proteins. cell Titer 96® AQueous one proliferation kit was applied for detect cell viability of Chondrocytes transfected with negative control vector, pcDNA3.1 PCAT-1 plasmid or siRNA against PCAT-1. RNA pull-down assays and Luciferase reporter assay were used to confirm the connection. SPSS 17.0 was employed for statistical analysis.

RESULTS

We found that the expressions of PCAT-1 were up-regulated in OA chondrocytes compared with normal chondrocytes. si-PCAT-1 suppressed apoptotic OA chondrocytes. Over-expression of PCAT-1 enhanced the apoptosis of normal chondrocytes. In addition, the online database and luciferase assay confirmed that PCAT-1 could directly target miR-27b-3p. PCAT-1 could promote the apoptosis of OA and normal chondrocytes through binding with miR-27b-3p.

CONCLUSIONS

Based on the comparisons and analysis, we could conclude that lncRNA PCAT-1 regulated the apoptosis of chondrocytes through sponging miR-27b-3p in OA. PCAT-1 has potential values to act as a new therapeutic target for OA patients.

VARAdb: a comprehensive variation annotation database for human

With the study of human diseases and biological processes increasing, a large number of non-coding variants have been identified and facilitated. The rapid accumulation of genetic and epigenomic information has resulted in an urgent need to collect and process data to explore the regulation of non-coding variants. Here, we developed a comprehensive variation annotation database for human (VARAdb, http://www.licpathway.net/VARAdb/), which specifically considers non-coding variants. VARAdb provides annotation information for 577,283,813 variations and novel variants, prioritizes variations based on scores using nine annotation categories, and supports pathway downstream analysis. Importantly, VARAdb integrates a large amount of genetic and epigenomic data into five annotation sections, which include ‘Variation information’, ‘Regulatory information’, ‘Related genes’, ‘Chromatin accessibility’ and ‘Chromatin interaction’. The detailed annotation information consists of motif changes, risk SNPs, LD SNPs, eQTLs, clinical variant-drug-gene pairs, sequence conservation, somatic mutations, enhancers, super enhancers, promoters, transcription factors, chromatin states, histone modifications, chromatin accessibility regions and chromatin interactions. This database is a user-friendly interface to query, browse and visualize variations and related annotation information. VARAdb is a useful resource for selecting potential functional variations and interpreting their effects on human diseases and biological processes.

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.

LncRNA TTN-AS1/miR-134-5p/PAK3 axis regulates the radiosensitivity of human large intestine cancer cells through the P21 pathway and AKT/GSK-3β/β-catenin pathway

Radiotherapy is an important adjuvant treatment for large intestine cancer even though it does not cause any response in many patients. The present study aimed to investigate the effects of the TTN antisense RNA 1 (TTN-AS1) long noncoding RNA (lncRNA) on radiotherapy dynamics of large intestine cancer cells and to explore the underlying molecular mechanisms. TTN-AS1 expression was evaluated by reverse-transcription quantitative polymerase chain reaction, western blot, and cellular immunofluorescence, and flow cytometry analysis was used to measure apoptosis. Radiotherapy was simulated in vitro by exposing cancer cells to X-ray. TTN-AS1 was highly expressed in large intestine cancer cells after an X-ray exposition for 24 hr. TTN-AS1 knockdown improved the radiosensitivity of large intestine cancer cells and promoted apoptosis by increasing Bax/Bcl2 protein expression and the active-caspase 3/caspase 3 ratios following X-ray treatment. In addition, TTN-AS1 negatively regulated miR-134-5p expression, and miR-134-5p-mimic transfection decreased PAK3 protein expression in large intestine cancer cells. Importantly, TTN-AS1 promoted PAK3 and P21 protein expression in HT29 cells after X-ray treatment. Moreover, the knockdown of P21 protein expression improved radiosensitivity and promoted X-ray-induced apoptosis of HT29 cells. Finally, PAK3 knockdown expression decreased the p-AKT/AKT and p-GSK-3β/GSK-3β ratios and promoted the β-catenin transfer from the nucleus to the cytoplasm. These data suggest that the TTN-AS1 lncRNA promoted resistance to radiotherapy of large intestine cancer cells by increasing PAK3 expression via miR-134-5p inhibition, and this may be related to the P21 and AKT/GSK-3β/β-catenin 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.

Data Mining and Expression Analysis of Differential lncRNA ADAMTS9-AS1 in Prostate Cancer

Long noncoding RNAs (lncRNAs) play important roles in the regulation of gene expression by acting as competing endogenous RNAs (ceRNAs). However, the roles of lncRNA-associated ceRNAs in oncogenesis are not fully understood. The present study aims to determine whether a ceRNA network can serve as a prognostic marker in human prostate cancer (PCa). In order to identify a ceRNA network and the key lncRNAs in PCa, we constructed a differentially expressed lncRNAs (DELs)-differentially expressed miRNAs (DEMis)-differentially expressed mRNAs (DEMs) regulatory network based on the ceRNA theory using data from the Cancer Genome Atlas (TCGA). We found that the DELs-DEMis-DEMs network was composed of 27 DELs nodes, seven DEMis nodes, and three DEMs nodes. The 27 DELs were further analyzed with several public databases to provide meaningful information for understanding the functional roles of lncRNAs in regulatory networks in PCa. We selected ADAMTS9-AS1 to determine its role in PCa and found that ADAMTS9-AS1 significantly influences tumor cell growth and proliferation, suggesting that it plays a tumor suppressive role. In addition, ADAMTS9-AS1 functioned as ceRNA, effectively becoming a sponge for hsa-mir-96 and modulating the expression of PRDM16. These results suggest that ceRNAs could accelerate biomarker discovery and therapeutic strategies for PCa.

BBOX1-AS1 contributes to colorectal cancer progression by sponging hsa-miR-361-3p and targeting SH2B1

Colorectal cancer (CRC) is the third main cause of cancer‐relevant deaths worldwide, and its incidence has increased in recent decades. Previous studies have indicated that certain long noncoding RNAs (lncRNAs) have regulatory roles in tumor occurrence and progression. Often, lncRNAs are competitive endogenous RNAs that sponge microRNAs to up‐regulate mRNAs. Here, we examined the role of a novel lncRNA gamma‐butyrobetaine hydroxylase 1 antisense RNA 1 (BBOX1‐AS1) in CRC. We observed that BBOX1‐AS1 is overexpressed in CRC cell lines, and BBOX1‐AS1 knockdown enhances cell proliferation, migration and invasion while reducing cell apoptosis. miR‐361‐3p is present at a low level in CRC and is negatively modified by BBOX1‐AS1. Moreover, miR‐361‐3p was validated to be targeted by BBOX1‐AS1. Src homology 2 B adaptor protein 1 (SH2B1) was notably upregulated in CRC cell lines and was identified as a downstream gene of miR‐361‐3p. In addition, we found that miR‐361‐3p amplification can suppress the expression of SH2B1. Finally, data from rescue assays suggested that overexpression of SH2B1 counteracted BBOX1‐AS1 silencing‐mediated inhibition of CRC progression. In conclusion, BBOX1‐AS1 promotes CRC progression by sponging hsa‐miR‐361‐3p and up‐regulating SH2B1.

LncRNA PCAT1 promotes metastasis of endometrial carcinoma through epigenetical downregulation of E-cadherin associated with methyltransferase EZH2

More than 140 thousands of women suffer from endometrial carcinoma in the worldwide, and over 40 thousand of the patients die before and after in surgery and chemoradiotherapy because of its metastasis. However, its molecular mechanism is much less known compared to other cancers. In this study, we demonstrated that long non-coding RNA PCAT1 is dramatically increased in the tissues and plasma from endometrial carcinoma (EC) (n = 100, all p < 0.001) controlled by its paracancerous tissue, and cell lines including RL-952, HEC-1-B, KLE, Ishikawa, and AN3CA compared to the cells from normal endometrium (all p < 0.001). When lncRNA PCAT1 was knocked-down, the KLE and AN3CA cells exhibited slow capability on proliferation and colony formation in vitro. With the silence of lncRNA PCAT1, the cells were markedly inhibited on migration and invasion in vitro (all p < 0.001), which were confirmed on the EC patient subjects. When expressions of lncRNA PCAT1 were interfered in the cells, expressions of E-cadherin but not N-cadherin and Vimentin were significantly promoted with a strong up-regulation accompanied by nearly completed recoveries on migration and invasion (all p < 0.001). In order to analyze the association of lncRNA PCAT1 and E-cadherin, we silenced the expressions of both genes and unveiled that EC migration and invasion were significantly congested (all p < 0.001). Importantly, we found that the E-cadherin down-regulation caused by lncRNA PCAT1 associates with histone methyltransferase EZH2. When over-expression of EZH2 was applied in the PCAT1 silenced cells, the expression of E-cadherin experienced significant decrease in the cell lines. Reversely, when expression of EZH2 was annulled in the PCAT1 silenced cells, the expression of E-cadherin was significantly boosted in the cells (all p < 0.001). Furthermore, the interaction of lncRNA PCAT1 and EZH2 were approved with immunoprecipitation. Our data demonstrated that the methyltransferase EZH2 related up-regulation of lncRNA PCAT1 along with down-regulation of E-cadherin could be essential in oncogenesis of endometrial carcinoma in both EC cells and patient subjects. These compact data suggest that combination of lncRNA PCAT1, EZH2 and E-cadherin could provide valued information for efficient EC diagnostics, which would propose a potential target for EC treatment with EZH2i on methyltransferation.

LncRNA PCAT-1 Promoted ESCC Progression via Regulating ANXA10 Expression by Sponging miR-508-3p

Background

Given the poor prognosis of metastatic esophageal squamous cell carcinoma (ESCC) patients, molecular mechanisms underlying the progression and metastasis of ESCC are highly desired in the scientific community. Prostate cancer associated transcript-1 (PCAT-1) is a lncRNA up-regulated in major types of cancers and is associated with the poor prognosis of cancer patients. This study aimed to understand the expression and role of PCAT-1 in the progression and metastasis of ESCC and to identify the potential lncRNA-miRNA interactions and signaling pathways underlying the mechanisms of action of PCAT-1 in ESCC.

Materials and Methods

Gene expression levels were determined by qRT-PCR; protein levels were determined by Western blot assay; cell proliferation, invasion and migration were determined by CCK-8, Transwell invasion and wound healing assays, respectively; in vivo tumor growth was evaluated by xenograft nude mice model.

Results

Our data showed the up-regulation of PCAT-1 in different human ESCC cell lines and in clinical ESCC tissues. Knockdown of PCAT-1 in ESCC cells significantly inhibited the proliferation, invasion and migration of the cancer cells. Moreover, we showed the interactions between PCAT-1 and miR-508-3p and demonstrated that PCAT-1 was able to repress miR-508-3p expression in ESCC cells via acting as a competing endogenous RNA. Besides, Annexin A10 (ANXA10) was identified to be the downstream target of the PCAT-1 and miR-508-3p interactions.

Conclusion

This study demonstrated the functional role of PCAT-1 in promoting the proliferation, invasion and migration of ESCC cells. We also identified a PCAT-1/miR-508-3p/ANXA10 axis in mediating the promoting role of PCAT-1 in the progression of ESCC. The findings provide experimental evidence to support lncRNA PCAT-1 as a potential therapeutic target of ESCC.

LINC00858 promotes retinoblastoma cell proliferation, migration and invasion by inhibiting miR-3182

The aim of the present study was to determine the role of long intergenic non-protein coding RNA 858 (LINC00858) in retinoblastoma (RB) and investigate the underlying molecular mechanisms. RB tissues and paracancerous tissues of 27 RB cases were obtained. RB cell lines (SO-RB50, Y79, HXO-RB44 and WERI-Rb1) and a normal retinal epithelial cell line (ARPE-19) were cultured for in vitro experiments. Batches of SO-RB50 and Y79 cells were assigned to groups transfected with small interfering RNA targeting LINC00858 (si-LINC00858 group), microRNA (miR)-3182 mimics or inhibitor, or the respective controls. A Cell Counting Kit-8 and Transwell assays were performed to assess the effect of the transfections on the proliferation, migration and invasion of SO-RB50 and Y79 cells. A luciferase reporter assay was performed using SO-RB50 cells to demonstrate the direct binding of LINC00858 and miR-3182. Reverse transcription-quantitative PCR was employed to detect LINC00858 and miR-3182 expression. Pearson correlation analysis was used to assess the correlation between the expression of LINC00858 and miR-3182. The results indicated that RB tissues and cells exhibited aberrantly elevated LINC00858 expression (P<0.05). Compared with those in the control-transfected group, SO-RB50 and Y79 cells of the si-LINC00858 group had a lower cell proliferation, as well as a lower number of migrated and invaded cells (all P<0.05). miR-3182 was proven to be a target gene of LINC00858, to be abnormally downregulated in RB tissues and cells (P<0.05) and to be negatively correlated with LINC00858 expression. Compared with those in the si-LINC00858 + inhibitor-negative control group, SO-RB50 and Y79 cells of the si-LINC00858 + miR-3182 inhibitor group exhibited a significantly higher relative proliferation, migration and invasion (all P<0.05). In conclusion, LINC00858 promoted RB cell proliferation, migration and invasion, at least partially by inhibiting miR-3182.

Genome-wide expression profiling in colorectal cancer focusing on lncRNAs in the adenoma-carcinoma transition

Background

Long non-coding RNAs (lncRNAs) play a fundamental role in colorectal cancer (CRC) development, however, lncRNA expression profiles in CRC and its precancerous stages remain to be explored. We aimed to study whole genomic lncRNA expression patterns in colorectal adenoma–carcinoma transition and to analyze the underlying functional interactions of aberrantly expressed lncRNAs.

Methods

LncRNA expression levels of colonic biopsy samples (20 CRCs, 20 adenomas (Ad), 20 healthy controls (N)) were analyzed with Human Transcriptome Array (HTA) 2.0. Expression of a subset of candidates was verified by qRT-PCR and in situ hybridization (ISH) analyses. Furthermore, in silico validation was performed on an independent HTA 2.0, on HGU133Plus 2.0 array data and on the TCGA COAD dataset. MiRNA targets of lncRNAs were predicted with miRCODE and lncBase v2 algorithms and miRNA expression was analyzed on miRNA3.0 Array data. MiRNA-mRNA target prediction was performed using miRWALK and c-Met protein levels were analyzed by immunohistochemistry. Comprehensive lncRNA-mRNA-miRNA co-expression pattern analysis was also performed.

Results

Based on our HTA results, a subset of literature-based CRC-associated lncRNAs showed remarkable expression changes already in precancerous colonic lesions. In both Ad vs. normal and CRC vs. normal comparisons 16 lncRNAs, including downregulated LINC02023, MEG8, AC092834.1, and upregulated CCAT1, CASC19 were identified showing differential expression during early carcinogenesis that persisted until CRC formation (FDR-adjusted p < 0.05). The intersection of CRC vs. N and CRC vs. Ad comparisons defines lncRNAs characteristic of malignancy in colonic tumors, where significant downregulation of LINC01752 and overexpression of UCA1 and PCAT1 were found. Two candidates with the greatest increase in expression in the adenoma-carcinoma transition were further confirmed by qRT-PCR (UCA1, CCAT1) and by ISH (UCA1). In line with aberrant expression of certain lncRNAs in tumors, the expression of miRNA and mRNA targets showed systematic alterations. For example, UCA1 upregulation in CRC samples occurred in parallel with hsa-miR-1 downregulation, accompanied by c-Met target mRNA overexpression (p < 0.05).

Conclusion

The defined lncRNA sets may have a regulatory role in the colorectal adenoma-carcinoma transition. A subset of CRC-associated lncRNAs showed significantly differential expression in precancerous samples, raising the possibility of developing adenoma-specific markers for early detection of colonic lesions.

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.

Roles of long non-coding RNAs in colorectal cancer tumorigenesis: A Review

Long non-coding RNAs (lncRNAs) are newly identified potential biological and gene regulators. Similar to other cell-free circulating cancer-related nucleic acids, lncRNAs are released in the peripheral circulation of cancer patients and allow for non-invasive gene expression assessment. lncRNAs are considered to be promising biomarkers for cancer prognosis and diagnosis. Several lncRNAs have been found to regulate developmental processes in a number of biological disorders. Recent studies indicated that lncRNAs are associated with numerous diseases, most notably cancer, as they were found to be highly expressed or silenced in a number of human cancers, including colorectal cancer (CRC). Despite advances in the current detection methods, over half of cancer patients succumb to the disease, as several CRC cases are diagnosed at an advanced stage. Due to the lack of non-invasive and low-cost prognostic and diagnostic tests for CRC, the identification of novel, potentially effective biomarkers has been attracting increasing attention in recent cancer research. The present review focused on the most widely applied lncRNAs in cancer detection, including CRC, in vitro.

LncRNA-PCAT-1 promotes non-small cell lung cancer progression by regulating miR-149-5p/LRIG2 axis

Long noncoding RNAs (lncRNAs) are key players in the development and progression of human cancers. The lncRNA PCAT-1 has been shown to be upregulated in human non-small cell lung cancer (NSCLC); however, its role and molecular mechanisms in NSCLC cell progression remain unclear. Here, we found that the higher expression of PCAT-1 led to a significantly poorer survival time, and multivariate analysis revealed that PCAT-1 was an independent risk factor of prognosis in NSCLC. Furthermore, we also found that the knockdown of PCAT-1 remarkably suppressed cell growth by inducing cell cycle arrest and apoptosis promotion in NSCLC cells. Moreover, the bioinformatics analysis and luciferase reporter assay revealed that PCAT-1 directly bound to the miR-149-5p, which has been reported to act as a tumor suppressor in diverse cancers. In addition, our results confirmed that the tumor-promoting effects of PCAT-1 in NSCLC cells are at least partly through negative modulation of miR-149-5p. Finally, mechanistic investigations showed that PCAT-1 upregulated the expression of miR-149-5p target gene leucine-rich repeats and immunoglobulin (Ig)-like domains 2 (LRIG2) through competitively "spongeing" miR-149-5p. Therefore, we concluded that PCAT-1 may promote the development of NSCLC through the miR-149-5p/LRIG2 axis.

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.

Knockdown of long non-coding RNA TUG1 suppresses nasopharyngeal carcinoma progression by inhibiting epithelial-mesenchymal transition (EMT) via the promotion of miR-384

Nasopharyngeal carcinoma (NPC) is a cancer arising from the nasopharynx epithelium. Long non-coding RNAs (lnc RNA) play a critical role in various biological processes such as cell growth, embryonic development, and tumorigenesis. In the study, for the first time, we discovered that lnc RNA taurine upregulated gene 1 (TUG1) exhibited higher expression levels in NPC tissues and NPC cell lines than in normal nasopharyngeal epithelial tissues and normal nasopharyngeal cell line. In addition, patients with NPCs showing higher levels of TUG1 had worse overall survivals. Further, suppressing TUG1 expression markedly reduced the cell proliferation, migration and invasion; however, TUG1 over-expression significantly enhanced the proliferation, migration and invasion in NPC cells. TUG1 knockdown-inhibited epithelial-mesenchymal transition (EMT) was evidenced by the reduced expression of Vimentin, N-cadherin and transforming growth factor (TGF)-β1, while the enhanced level of E-cadherin. The results of luciferase reporter analysis verified that miR-384 was a direct target of TUG1 in NPC, and was down-regulated in NPC tissues, exhibiting suppressive role in cell proliferation, migration and invasion. In vivo, TUG1 knockdown reduced tumor growth via the regulation of miR-384 by restraining EMT development. In conclusion, our findings suggested that there was a negative correlation between TUG1 and miR-384 in NPC patients. TUG1 might be an effective candidate for use in NPC diagnosis, prognosis and treatment.

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.

lncRNAs in Non-Malignant Tissue Have Prognostic Value in Colorectal Cancer

Although colorectal cancer (CRC) is the third most frequent cause of cancer related death in Europe, clinically relevant biomarkers for therapy guidance and prognosis are insufficiently reliable. Long non-coding RNAs (lncRNAs) are RNAs over 200 nucleotides long that are not translated into proteins but can influence biological processes. There is emerging evidence for their involvement in solid cancer as oncogenes, tumour suppressors or regulators of cell proliferation and metastasis development. The goal of this study was to evaluate the prognostic effect of selected lncRNAs in a retrospective study on CRC patients from the Czech Republic. We used a quantitative PCR approach to measure the expression in paired non-malignant and tumour tissue samples of CRC patients of nine lncRNAs previously shown to be involved in cancer progression—ANRIL, CCAT1, GAS5, linc-ROR, MALAT1, MIR155HG, PCAT1, SPRY4-IT1 and TUG1. Associations between expression and expression ratios and clinical characteristics and survival were assessed by using univariable Cox proportional hazards models, Kaplan-Meier estimations with the Gehan-Wilcoxon test, the Mann-Whitney U test, the Kruskal-Wallis test and Spearman’s correlations. A comparison of expression in tumour tissue (TT) and non-malignant mucosa tissue (MT) showed significant upregulation of CCAT1 and linc-ROR in TT (p < 0.001 and p = 0.001, respectively) and downregulation of ANRIL, MIR155HG and MALAT1 (p = 0.001, p = 0.010, p = 0.001, respectively). Linc-ROR was significantly associated with the presence of synchronous metastases (p = 0.033). For individual tissue types, lower MIR155HG expression in TT was correlated with both shorter overall survival (p = 0.008) and shorter disease-free survival (p = 0.040). In MT, expression ratios of CCAT1/ANRIL and CCAT1/MIR155HG were associated with overall survival (p = 0.005 and p = 0.006, respectively). Our results revealed that changes in expression of lncRNAs between MT and TT hold potential to be used as prognostic biomarkers in CRC patients. Moreover, the ratios of CCAT1 to ANRIL and MIR155HG in MT also exhibit potential for prognosis assessment without tumour sampling. Our results also indicate that cancer progression is associated with detrimental system-wide changes in patient tissue, which might govern patient survival even after successful elimination of tumour or cancerous cells.

Long non-coding RNAs: crucial regulators of gastrointestinal cancer cell proliferation

Studies of long non-coding RNAs (lncRNAs) have been prevalent in the field of non-coding RNA regulation in recent years. LncRNAs exert crucial effects on malignant cell processes in the gastrointestinal system, including proliferation. Aberrant lncRNA expression, through both oncogenes and tumor suppressor genes, is instrumental to tumor cell proliferation. Here, we summarize the different molecular mechanisms and relevant signaling pathways through which multifarious lncRNAs regulate cell proliferation and we show that lncRNAs are potential biomarkers for gastrointestinal cancers.

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.

Long non-coding RNA SOX21-AS1 sponges miR-145 to promote the tumorigenesis of colorectal cancer by targeting MYO6

Emerging evidences have proved that long non-coding RNAs (lncRNAs) act as important molecular regulator in the tumor progression, including colorectal cancer (CRC). LncRNA SOX21-AS1 has been verified as oncogenic molecular in other cancers and tumorigenesis. In present study, our team investigates the clinical characteristic and molecular function in CRC carcinogenesis. Results showed that lncRNA SOX21-AS1 expression was significantly over-expressed in CRC tissue samples and cells. The aberrant over-expression of SOX21-AS1 indicated poor prognosis of CRC patients. In vitro and in vivo validation experiments, SOX21-AS1 silencing inhibited the proliferation, invasion, and decreased the tumor growth of CRC cells. Moreover, miR-145 was proved to be the target of SOX21-AS1, besides, myosin VI (MYO6) was found to be one of the targets of miR-145 using bioinformatics prediction programs and rescue confirmation experiments. In summary, our study reveals the tumorigenic effect of lncRNA SOX21-AS1 in CRC cells via targeting miR-145/MYO6, providing a novel insight for CRC carcinogenesis.

To Wnt or Lose: The Missing Non-Coding Linc in Colorectal Cancer

Colorectal cancer (CRC) is the third most frequent cancer and one of the leading causes for cancer-related mortality. Aberrant activation of the Wnt signaling is an essential initiating factor in colon carcinogenesis, and a driving force of CRC progression. Recently, long non-coding RNAs (lncRNAs) have emerged as significant players in CRC pathogenesis through diversified mechanisms. Although both Wnt signaling and lncRNAs represent interesting research areas for CRC, an effort of directly connecting these two areas is lacking. To fill in the knowledge gap, we focus on the reported findings of lncRNAs that regulate Wnt signaling or essential Wnt signaling targets. These include several newly discovered lncRNAs originated from the amplified cancer-associated chromosome 8q24 region that surrounds the essential Wnt target MYC gene, lncRNAs reported to be involved in CRC stem cells, and several individual lncRNAs connected to Wnt signaling through other mechanisms. This review will provide essential information that assists in understanding the missing link of lncRNAs to the classical Wnt signaling in CRC.