Long non-coding RNA UCA1 promotes breast tumor growth by suppression of p27 (Kip1)

LncRNA UCA1 in anti-cancer drug resistance

The pivotal role of the long non-coding RNA (lncRNA) urothelial carcinoma associated 1 (UCA1) in anti-cancer drug resistance has been confirmed in many cancers. Overexpression of lncRNA UCA1 correlates with resistance to chemotherapeutics such as cisplatin, gemcitabine, 5-FU, tamoxifen, imatinib and EGFR-TKIs, whereas lncRNA UCA1 knockdown restores drug sensitivity. These studies highlight the potential of lncRNA UCA1 as a diagnostic and prognostic biomarker, and a therapeutic target in malignant tumors. In this review, we address the role of lncRNA UCA1 in anti-cancer drug resistance and discuss its potential in future clinical applications.

Noncoding RNAs in Cancer Diagnosis

The accuracy and efficiency of tumor treatment depends mainly on early and precise diagnosis. Although histopathology is always the gold standard for cancer diagnosis, noninvasive biomarkers represent an opportunity for early detection and molecular staging of cancer. Besides the classical tumor markers, noncoding RNAs (ncRNAs) emerge to be a novel category of biomarker for cancer diagnosis since the dysregulation of ncRNAs is closely associated with the development and progression of human cancers such as liver, lung, breast, gastric, and other kinds of cancers. In this chapter, we will summarize the different types of ncRNAs in the diagnosis of major human cancers. In addition, we will introduce the recent advances in the detection and applications of circulating serum or plasma ncRNAs and non-blood fluid ncRNAs because the noninvasive body fluid-based assays are easy to examine for cancer diagnosis and monitoring.

Long noncoding RNA UCA1 induced by SP1 promotes cell proliferation via recruiting EZH2 and activating AKT pathway in gastric cancer

Long noncoding RNA UCA1 has emerged as a novel regulator in cancer initiation and progression of various cancers. However, function and underlying mechanism of UCA1 in the progression of gastric cancer (GC) remain unclear. In the present study, we report that UCA1 expressed highly in GC tissues and GC cells, which was partly induced by SP1. UCA1 promoted GC cell proliferation and G1/S transition in vitro and in vivo. Moreover, UCA1 exerted its function through interacting with EZH2, promoting direct interaction with cyclin D1 promoter to activate the translation of cyclin D1. Furthermore, AKT/GSK-3B/cyclin D1 axis was activated to upregulate cyclin D1 due to overexpression of UCA1. In addition, EZH2 and phosphorylated AKT induced by UCA1 could impact each other to form a positive feedback to promote cyclin D1 expression. This study demonstrated that UCA1 as a critical regulator involved in GC proliferation and cell cycle progression by promoting cyclin D1 expression, which indicates that it may be clinically a potential therapeutic target in GC.

LncRNA UCA1 promotes renal cell carcinoma proliferation through epigenetically repressing p21 expression and negatively regulating miR-495

Long non-coding RNAs have recently emerged as important regulators in the pathogenesis and progression of cancers. The long non-coding RNA urothelial carcinoma–associated 1 is reportedly upregulated and functions as an oncogene in some tumors. However, the role of urothelial carcinoma–associated 1 in renal cell carcinoma is not well elucidated so far. In this study, we found that urothelial carcinoma–associated 1 was overexpressed in renal cell carcinoma tissues compared with the adjacent normal tissues, and higher urothelial carcinoma–associated 1 expression levels were positively associated with advanced tumor stage and poor survival time in renal cell carcinoma patients. Further studies showed that knockdown of urothelial carcinoma–associated 1 suppressed renal cell carcinoma cell proliferation and S-phase cell number in vitro. Moreover, urothelial carcinoma–associated 1 was found to be associated with enhancer of zeste homolog 2, which suppressed p21 expression through histone methylation (H3K27me3) on p21 promoter. We also showed that knockdown of urothelial carcinoma–associated 1 increased the p21 protein expression through regulating enhancer of zeste homolog 2. In addition, bioinformatics analysis and dual-luciferase reporter assays confirmed that miR-495 was a target of urothelial carcinoma–associated 1 in renal cell carcinoma, and urothelial carcinoma–associated 1 promoted cell proliferation by negatively regulating miR-495. These findings illuminated that urothelial carcinoma–associated 1 promoted renal cell carcinoma progression through enhancer of zeste homolog 2 and interacted with miR-495. Overall, overexpression of urothelial carcinoma–associated 1 functions as an oncogene in renal cell carcinoma that may offer a novel therapeutic target for renal cell carcinoma patients.

The long noncoding RNA urothelial carcinoma-associated 1 overexpression as a poor prognostic biomarker in clear cell renal cell carcinoma

Long noncoding RNA urothelial carcinoma-associated 1 has previously played important roles in cancer. However, its role is still unknown in clear cell renal cell carcinoma. We utilized the most recent molecular and clinical data of clear cell renal cell carcinoma from The Cancer Genome Atlas project, and the relationship between urothelial carcinoma-associated 1 expression and the clinicopathological features was analyzed. Our results indicated that urothelial carcinoma-associated 1 overexpression was associated with male ( p = 0.003), wild-type PBRM1 ( p = 0.021), and BAP1 mutation ( p = 0.022) in clear cell renal cell carcinoma, although lower expression was found in tumors compared with normal controls, validated in tumor tissues from The Cancer Genome Atlas and 21 clear cell renal cell carcinoma patients at our hospital. Moreover, urothelial carcinoma-associated 1 overexpression indicated poor prognosis independently (Hazard Ratio [HR]: 1.92, p = 0.000) in clear cell renal cell carcinoma; it might be a potential detrimental gene considered as a predictive biomarker involved in clear cell renal cell carcinoma.

Shining the Light on Senescence Associated LncRNAs

Cellular senescence can be described as a complex stress response that leads to irreversible cell cycle arrest. This process was originally described as an event that primary cells go through after many passages of cells during cell culture. More recently, cellular senescence is viewed as a programmed process by which the cell displays a senescence phenotype when exposed to a variety of stresses. Cellular senescence has been implicated in tumor suppression and aging such that senescence may contribute to both tumor progression and normal tissue repair. Here, we review different forms of cellular senescence, as well as current biomarkers used to identify senescent cells in vitro and in vivo. Additionally, we highlight the role of senescence-associated long noncoding RNAs (lncRNAs).

Upregulation of the long noncoding RNA UCA1 affects the proliferation, invasion, and survival of hypopharyngeal carcinoma

Background

Several long noncoding RNAs (lncRNAs) are involved in oncogenesis.

Methods and Results

Our microarray analysis showed that numerous lncRNAs are dysregulated in hypopharyngeal squamous cell carcinoma (HSCC) tumor tissues as compared with normal tissues. Among those lncRNAs, urothelial carcinoma-associated 1 (UCA1) has been found to have an oncogenic role in HSCC. We confirmed the upregulation of UCA1 in HSCC by assessing its expression levels in a cohort of 53 patient tumors and paired non-tumor samples. In addition, we found that high UCA1 expression was significantly associated with advanced T category, late clinical stage, greater lymphatic invasion, and worse prognosis. Furthermore, in vitro experiments demonstrated that UCA1 functioned as an oncogene by promoting the proliferation and invasion and preventing the apoptosis of HSCC cells.

Conclusions

Taken together, our findings for the first time identify the role of UCA1 as a tumor promoter and a pro-metastatic factor in HSCC, demonstrating that UCA1 is a potential prognostic biomarker and therapeutic target in HSCC.

UCA1 Regulates the Growth and Metastasis of Pancreatic Cancer by Sponging miR-135a

Pancreatic cancer (PC) is a devastating malignant disease with a poor prognosis. This study aimed to investigate the role of urothelial carcinoma associated 1 (UCA1) in the progression of PC. Our results revealed that long noncoding RNA (lncRNA) UCA1 was overexpressed in PC tissues compared with adjacent histologically normal tissues. A downregulated level of UCA1 was also detected in five human PC cell lines (SW1990, BxPC-3, MiaPaCa-2, PANC-1, and CAPAN-1) compared with normal pancreatic duct epithelial HPDE cells. The proliferation of PC cells was inhibited after UCA1 was suppressed by a lentiviral vector. The cell apoptosis rate was largely promoted by downregulating UCA1. Further research revealed that microRNA (miRNA)-135a is a direct target of UCA1. The expression of miR-135a was decreased in PC tissues and cell lines compared with control groups. In addition, the decreased level of miR-135a was elevated by adding miR-135a mimic in SW1990 cells transfected with lncRNA UCA1. Similarly, an upregulated level of miR-135a was downregulated by adding miR-135a inhibitor in SW1990 cells transfected with UCA1 siRNA. Luciferase activity assay further confirmed the targeting relationship between UCA1 and miR-135a. Moreover, miR-135a reversed the effect of UCA1 on cell apoptosis rate and cell viability in SW1990 cells. The migration and invasion capacities of PC cells were suppressed by UCA1. siRNA was then enhanced by the miR-135a inhibitor. In vivo, UCA1 siRNA effectively suppressed tumor growth and the expression of migration markers. Taken together, our research revealed that UCA1 works as an oncogene by targeting miR-135a. The UCA1–miR-135a pathway regulated the growth and metastasis of PC, providing new insight in the treatment of PC.

A three-long noncoding RNA signature as a diagnostic biomarker for differentiating between triple-negative and non-triple-negative breast cancers

BACKGROUND

Triple-negative breast cancer (TNBC) is an aggressive cancer with unfavorable outcome and it is useful to explore noninvasive biomarkers for its early diagnosis. Here, we identified differentially expressed long noncoding RNAs (lncRNAs) in blood samples of patients with TNBC to assess their diagnostic value.

METHODS

Differential expression of lncRNAs in plasma of patients with TNBC (n = 25) and non-TNBC (NTNBC; n = 35) and in healthy controls was compared by microarray analysis and validated by real-time PCR. lncRNA expression between plasma and BC tissues was compared using Pearson correlation test. Logit model was used to obtain a new lncRNA-based score. Receiver operating characteristic analysis was performed to assess the diagnostic value of the selected lncRNAs.

RESULTS

Microarray data showed that 41 lncRNAs were aberrantly expressed. Among these, antisense noncoding RNA in the INK4 locus (ANRIL), hypoxia inducible factor 1alpha antisense RNA-2 (HIF1A-AS2), and urothelial carcinoma-associated 1 (UCA1) were markedly upregulated in plasma of patients with TNBC compared with patients with NTNBC (P < 0.01). HIF1A-AS2 expression was positively associated with its tissue levels (r = 0.670, P < 0.01). AUC (95% CI) of ANRIL, HIF1A-AS2, and UCA1 was 0.785 (0.660-0.881), 0.739 (0.610-0.844), and 0.817 (0.696-0.905), respectively. TNBCSigLnc-3, a new score obtained using the logit model, showed excellent diagnostic performance, with AUC of 0.934 (0.839-0.982), sensitivity of 76.0%, and specificity of 97.1%.

CONCLUSION

ANRIL, HIF1A-AS2, and UCA1 expression was significantly increased in plasma of patients with TNBC, suggesting their use as TNBC-specific diagnostic biomarkers.

Long non-coding RNA LINC00672 contributes to p53 protein-mediated gene suppression and promotes endometrial cancer chemosensitivity

Thousands of long intergenic non-protein coding RNAs (lincRNAs) have been identified in mammals in genome-wide sequencing studies. Some of these RNAs have been consistently conserved during the evolution of species and could presumably function in important biologic processes. Therefore, we measured the levels of 26 highly conserved lincRNAs in a total of 176 pairs of endometrial carcinoma (EC) and surrounding non-tumor tissues of two distinct Chinese populations. Here, we report that a lincRNA, LINC00672, which possesses an ultra-conserved region, is aberrantly down-regulated during the development of EC. Nevertheless, LINC00672 is a p53-targeting lincRNA acting along with heterogeneous nuclear ribonucleoproteins as a suppressive cofactor, which locally reinforces p53-mediated suppression of LASP1, an evolutionarily conserved neighboring gene of LINC00672 and putatively associated with increased tumor aggressiveness, during anti-tumor processes. LINC00672 overexpression could lower the levels of LASP1 and slow the development of malignant phenotypes of EC both in vitro and in vivo Moreover, LINC00672 significantly increased the 50% inhibitory concentration of paclitaxel in EC cells and increased the sensitivity of xenograft mice to paclitaxel. These findings indicate that LINC00672 can influence LASP1 expression as a locus-restricted cofactor for p53-mediated gene suppression, thus impacting EC malignancies and chemosensitivity to paclitaxel.

LncRNAs: From Basic Research to Medical Application

This review aimed to summarize the current research contents about long noncoding RNAs (lncRNAs) and some related lncRNAs as molecular biomarkers or therapy strategies in human cancer and cardiovascular diseases. Following the development of various kinds of sequencing technologies, lncRNAs have become one of the most unknown areas that need to be explored. First, the definition and classification of lncRNAs were constantly amended and supplemented because of their complexity and diversity. Second, several methods and strategies have been developed to study the characteristic of lncRNAs, including new species identifications, subcellular localization, gain or loss of function, molecular interaction, and bioinformatics analysis. Third, based on the present results from basic researches, the working mechanisms of lncRNAs were proved to be different forms of interactions involving DNAs, RNAs, and proteins. Fourth, lncRNA can play different important roles during the embryogenesis and organ differentiations. Finally, because of the tissue-specific expression of lncRNAs, they could be used as biomarkers or therapy targets and effectively applied in different kinds of diseases, such as human cancer and cardiovascular diseases.

Long noncoding RNAs (lncRNAs) in triple negative breast cancer

Long noncoding RNAs (lncRNAs) are dysregulated in many cancer types, which are believed to play crucial roles in regulating several hallmarks of cancer biology. Triple Negative Breast Cancer (TNBC) is a very aggressive subtype of normal breast cancer, which has features of negativity for ER, PR, and HER2. Great efforts have been made to identify an association between lncRNAs expression profiles and TNBC, and to understand the functional role and molecular mechanism on aberrant-expressed lncRNAs. In this review, we summarized the existed knowledge on the systematics, biology, and function of lncRNAs. The advances from the most recent studies of lncRNAs in the predicament of breast cancer, TNBC, are highlighted, especially the functions of specifically selected lncRNAs. We also discussed the potential value of these lncRNAs in TNBC, providing clues for the diagnosis and treatments of TNBC.

Insights from Global Analyses of Long Noncoding RNAs in Breast Cancer

PURPOSE OF REVIEW

The goal of this review was to compare and contrast the results and implications from several recent transcriptomic studies that analyzed the expression of lncRNAs in breast cancer. How many lncRNAs are dysregulated in breast cancer? Do dysregulated lncRNAs contribute to breast cancer etiology? Are lncRNAs viable biomarkers in breast cancer?

RECENT FINDINGS

Transcriptomic profiling of breast cancer tissues, mostly from The Cancer Genome Atlas, identified thousands of long noncoding RNAs that are expressed and dysregulated in breast cancer. The expression of lncRNAs alone can divide patients into molecular subtypes. Subsequent functional studies demonstrated that several of these lncRNAs have important roles in breast cancer cell biology.

SUMMARY

Thousands of lncRNAs are dysregulated in breast cancer that can be developed as biomarkers for prognostic or therapeutic purposes. The reviewed reports provide a roadmap to guide functional studies to discover lncRNAs with critical biological functions relating to breast cancer development and progression.

Long noncoding RNA HOXA-AS2 represses P21 and KLF2 expression transcription by binding with EZH2, LSD1 in colorectal cancer

Long noncoding RNAs (lncRNAs) have received increased attention as a new class of functional regulators involved in human carcinogenesis. HOXA cluster antisense RNA 2 (HOXA-AS2) is a 1048-bp lncRNA located between the HOXA3 and HOXA4 genes in the HOXA cluster that regulates gene expression at a transcription level. HOXA-AS2 is previously found to be overexpressed in gastric cancer (GC) and promotes GC cells proliferation. However, its potential role and molecular mechanism in colorectal cancer (CRC) are not known. Here, we identified that HOXA-AS2 is significantly upregulated in CRC tissue. In addition, increased HOXA-AS2 expression is associated with a larger tumor size and an advanced pathological stage in CRC patients. HOXA-AS2 knockdown significantly suppressed proliferation by blocking the G1/S transition and caused apoptosis of CRC cells in vitro and in vivo. The mechanistic investigations showed that HOXA-AS2 could interact with EZH2 (enhancer of zeste homolog 2), LSD1 (lysine specific demethylase 1) and recruit them to p21 (CDKN1A), KLF2 promoter regions to repress their transcription. Furthermore, the rescue experiments demonstrated that HOXA-AS2 oncogenic function is partly through regulating p21. In conclusion, our data suggest that HOXA-AS2 may function as an oncogene by modulating the multiple genes expression involved in CRC proliferation, and also provides a potential target for CRC therapy.

Epigenetic regulation of long noncoding RNA UCA1 by SATB1 in breast cancer

Special AT-rich sequence binding protein 1 (SATB1) is a nuclear matrix-associated DNA-binding protein that functions as a chromatin organizer. SATB1 is highly expressed in aggressive breast cancer cells and promotes growth and metastasis by reprograming gene expression. Through genomewide cross-examination of gene expression and histone methylation, we identified SATB1 target genes for which expression is associated with altered epigenetic marks. Among the identified genes, long noncoding RNA urothelial carcinoma-associated 1 (UCA1) was upregulated by SATB1 depletion. Upregulation of UCA1 coincided with increased H3K4 trimethylation (H3K4me3) levels and decreased H3K27 trimethylation (H3K27me3) levels. Our study showed that SATB1 binds to the upstream region of UCA1 in vivo, and that its promoter activity increases with SATB1 depletion. Furthermore, simultaneous depletion of SATB1 and UCA1 potentiated suppression of tumor growth and cell survival. Thus, SATB1 repressed the expression of oncogenic UCA1, suppressing growth and survival of breast cancer cells. [BMB Reports 2016; 49(10): 578-583].

Long Non-Coding RNAs: A Novel Paradigm for Toxicology

Long non-coding RNAs (lncRNAs) are over 200 nucleotides in length and are transcribed from the mammalian genome in a tissue-specific and developmentally regulated pattern. There is growing recognition that lncRNAs are novel biomarkers and/or key regulators of toxicological responses in humans and animal models. Lacking protein-coding capacity, the numerous types of lncRNAs possess a myriad of transcriptional regulatory functions that include cis and trans gene expression, transcription factor activity, chromatin remodeling, imprinting, and enhancer up-regulation. LncRNAs also influence mRNA processing, post-transcriptional regulation, and protein trafficking. Dysregulation of lncRNAs has been implicated in various human health outcomes such as various cancers, Alzheimer's disease, cardiovascular disease, autoimmune diseases, as well as intermediary metabolism such as glucose, lipid, and bile acid homeostasis. Interestingly, emerging evidence in the literature over the past five years has shown that lncRNA regulation is impacted by exposures to various chemicals such as polycyclic aromatic hydrocarbons, benzene, cadmium, chlorpyrifos-methyl, bisphenol A, phthalates, phenols, and bile acids. Recent technological advancements, including next-generation sequencing technologies and novel computational algorithms, have enabled the profiling and functional characterizations of lncRNAs on a genomic scale. In this review, we summarize the biogenesis and general biological functions of lncRNAs, highlight the important roles of lncRNAs in human diseases and especially during the toxicological responses to various xenobiotics, evaluate current methods for identifying aberrant lncRNA expression and molecular target interactions, and discuss the potential to implement these tools to address fundamental questions in toxicology.

Transcriptional profiling analysis and functional prediction of long noncoding RNAs in cancer

Long noncoding RNAs (lncRNAs), which are noncoding RNAs (ncRNAs) with length more than 200 nucleotides (nt), have been demonstrated to be involved in various types of cancer. Consequently, it has been frequently discussed that lncRNAs with aberrant expression in cancer serve as potential diagnostic biomarkers and therapeutic targets. However, one major challenge of developing cancer biomarkers is tumor heterogeneity which means that tumor cells show different cellular morphology, metastatic potential as well as gene expression. In this study, a custom designed microarray platform covering both mRNAs and lncRNAs was applied to tumor tissues of gastric, colon, liver and lung. 316 and 157 differentially expressed (DE-) protein coding genes and lncRNAs common to these four types of cancer were identified respectively. Besides, the functional roles of common DE-lncRNAs were inferred based on their expression and genomic position correlation with mRNAs. Moreover, mRNAs and lncRNAs with tissue specificity were also identified, suggesting their particular roles with regard to specific biogenesis and functions of different organs. Based on the large-scale survey of mRNAs and lncRNAs in four types of cancer, this study may offer new biomarkers common or specific for various types of cancer.

Knockdown of Long Non-Coding RNA UCA1 Increases the Tamoxifen Sensitivity of Breast Cancer Cells through Inhibition of Wnt/β-Catenin Pathway

Acquired resistance to tamoxifen remains a major obstacle in breast cancer (BC) treatment, since the underlying mechanism has not been fully elucidated. The long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) has been recently shown to be dysregulated and plays important roles in progression of breast cancer. In the present study, we aimed to investigate the biological role and clinical significance of UCA1 in BC drug resistance. Hence, we used quantitative PCR assay to evaluate the UCA1 expression in tissues from patients with BC as well as established tamoxifen-resistant BC cell lines in vitro. We tested the viability, invasive ability and apoptosis rate in MCF-7 and T47D cells using MTT assay, transwell assay and flow cytometry assay, respectively. The influence of UCA1 on tumorigenesis was monitored by in vivo mice xenograft model. The activation of Wnt/β-catenin signaling pathway was evaluated by immunofluorescence assay, western blot assay and luciferase reporter assay, respectively. We found that the expression of UCA1 positively correlated with the pathological grade and mortality of breast cancer patients, moreover, expressions of UCA1 was increased significantly in the tamoxifen-resistant cell lines compared with the wild type parental cells. Ectopic expression of UCA1 promoted cell survival and resistance to tamoxifen treatment, whereas inhibition of UCA1 enhanced tamoxifen sensitivity of BC cells and induced more apoptotic cells. In addition, tamoxifen-resistant cells exhibited increased Wnt signaling activation as measured by the TOP/FOP Wnt luciferase reporter assay and β-catenin protein level compared with parental MCF-7 and T47D cells, respectively. In line with these data, UCA1 depletion attenuated the activity of Wnt/β-catenin pathway activation and the tumorigenicity of the tamoxifen-resistant BC cells. Taken together, our data highlights the pivotal role of UCA1-Wnt/β-catenin signaling pathway in the tamoxifen resistance in breast cancer, which could be targeted to improve the effectiveness and efficacy of tamoxifen treatment in breast cancer.

lncRNA UCA1 Contributes to Imatinib Resistance by Acting as a ceRNA Against miR-16 in Chronic Myeloid Leukemia Cells

Imatinib (IM) has been applied to the chronic phase of chronic myeloid leukemia (CML) and has great benefit on the prognosis of patients with CML. The function of drug efflux mediated by multidrug resistance protein-1 (MDR1) is considered as a main reason for IM drug resistance in CML cells. However, the exact mechanisms of MDR1 modulation in IM resistance of CML cells remain unclear. In the present study, long noncoding RNA (lncRNA) UCA1 was identified as an important modulator of MDR1 by a model system of leukemia cell lines with a gradual increase of MDR1 expression and IM resistance. Overexpression of UCA1 increased MDR1 expression to promote IM resistance of CML cells. Furthermore, for the first time, we demonstrated that UCA1 functions as a competitive endogenous (ceRNA) of MDR1 through completely binding the common miR-16. UCA1-MDR1 might be a novel target for enhancing the therapeutic efficacy of CML patients with IM resistance.

Long non-coding RNA UCA1 contributes to the progression of oral squamous cell carcinoma by regulating the WNT/β-catenin signaling pathway

With the development of functional genomics studies, a mass of long non-coding RNAs (LncRNA) were discovered from the human genome. Long non-coding RNAs serve as pivotal regulators of genes that are able to generate LncRNA-binding protein complexes to modulate a great number of genes. Recently, the LncRNA urothelial carcinoma-associated 1 (UCA1) has been revealed to be dysregulated, which plays a critical role in the development of a few cancers. However, the role of the biology and clinical significance of UCA1 in the tumorigenesis of oral squamous cell carcinoma (OSCC) remain unknown. We found that UCA1 expression levels were upregulated aberrantly in tongue squamous cell carcinoma tissues and associated with lymph node metastasis and TNM stage. We explored the expression, function, and molecular mechanism of LncRNA UCA1 in OSCC. In the present work, we revealed that UCA1 silencing suppressed proliferation and metastasis and induced apoptosis of OSCC cell lines in vitro and in vivo, which might be related to the activation level of the WNT/β-catenin signaling pathway. Our research results emphasize the pivotal role of UCA1 in the oncogenesis of OSCC and reveal a novel LncRNA UCA1-β-catenin-WNT signaling pathway regulatory network that could contribute to our understanding in the pathogenesis of OSCC and assist in the discovery of a viable LncRNA-directed diagnostic and therapeutic strategy for this fatal disease.

The novel G-quadruplex-containing long non-coding RNA GSEC antagonizes DHX36 and modulates colon cancer cell migration

Long non-coding RNAs (lncRNAs) are frequently dysregulated in a variety of human cancers. However, their biological roles in these cancers remain incompletely understood. In this study, we analyze the gene expression profiles of colon cancer tissues and identify a previously unannotated lncRNA, FLJ39051, that we term GSEC (G-quadruplex-forming sequence containing lncRNA), as a lncRNA that is upregulated in colorectal cancer. We further demonstrate that knockdown of GSEC results in the reduction of colon cancer cell motility. We also show that GSEC binds to the DEAH box polypeptide 36 (DHX36) RNA helicase via its G-quadruplex-forming sequence and inhibits DHX36 G-quadruplex unwinding activity. Moreover, knockdown of DHX36 restores the reduced migratory activity of colon cancer cells caused by GSEC knockdown. These results suggest that GSEC plays an important role in colon cancer cell migration by inhibiting the function of DHX36 via its G-quadruplex structure.

Long Non-Coding RNA (lncRNA) Urothelial Carcinoma-Associated 1 (UCA1) Enhances Tamoxifen Resistance in Breast Cancer Cells via Inhibiting mTOR Signaling Pathway

Background

Long non-coding RNA (lncRNA) UCA1 is an oncogene in breast cancer. The purpose of this study was to investigate the role of UCA1 in tamoxifen resistance of estrogen receptor positive breast cancer cells.

Material/Methods

Tamoxifen sensitive MCF-7 cells were transfected for UCA1 overexpression, while tamoxifen resistant LCC2 and LCC9 cells were transfected with UCA siRNA for UCA1 knockdown. qRT-PCR was performed to analyze UCA1 expression. CCK-8 assay, immunofluorescence staining of cleaved caspase-9, and flow cytometric analysis of Annexin V/PI staining were used to assess tamoxifen sensitivity. Western blot analysis was performed to detect p-AKT and p-mTOR expression.

Results

LncRNA UCA1 was significantly upregulated in tamoxifen resistant breast cancer cells compared to tamoxifen sensitive cells. LCC2 and LCC9 cells transfected with UCA1 siRNA had significantly higher ratio of apoptosis after tamoxifen treatment. UCA1 siRNA significantly decreased the protein levels of p-AKT and p-mTOR in LCC2 and LCC9 cells. Enforced UCA1 expression substantially reduced tamoxifen induced apoptosis in MCF-7 cells, while rapamycin treatment abrogated the protective effect of UCA1.

Conclusions

UCA1 upregulation was associated with tamoxifen resistance in breast cancer. Mechanistically, UCA1 confers tamoxifen resistance to breast cancer cells partly via activating the mTOR signaling pathway.

Over-expression of the long non-coding RNA HOTTIP inhibits glioma cell growth by BRE

Background

Gliomas are the most common type of primary brain tumour in the central nervous system of adults. The long non-coding RNA (lncRNA) HOXA transcript at the distal tip (HOTTIP) is transcribed from the 5′ tip of the HOXA locus. HOTTIP has recently been shown to be dysregulated and play an important role in the progression of several cancers. However, little is known about whether and how HOTTIP regulates glioma development.

Methods

In this study, we assayed the expression of HOTTIP in glioma tissue samples and glioma cell lines using real-time polymerase chain reaction and defined the biological functions of HOTTIP using the CCK-8 assay, flow cytometry, terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL assay) and tumour formation assay in a nude mouse model. Finally, we discovered the underlying mechanism using the Apoptosis PCR 384HT Array, Western blot, RNA immunoprecipitation (RIP) and luciferase reporter assay.

Results

HOTTIP was aberrantly down-regulated in glioma tissues and glioma cell lines (U87-MG, U118-MG, U251 and A172), and over-expression of HOTTIP inhibited the growth of glioma cell lines in vitro and in vivo. Furthermore, HOTTIP could directly bind to the brain and reproductive expression (BRE) gene and down-regulate BRE gene expression. In addition, we further verified that over-expression of the BRE gene promoted the growth of glioma cell lines in vitro. Finally, over-expression of HOTTIP significantly suppressed the expression of the cyclin A and CDK2 proteins and increased the expression of the P53 protein. However, we found that the over-expression of BRE significantly increased the expression of the cyclin A and CDK2 proteins and suppressed the expression of the P53 protein. Taken together, these findings suggested that high levels of HOTTIP reduced glioma cell growth. Additionally, the mechanism of HOTTIP-mediated reduction of glioma cell growth may involve the suppression of cyclin A and CDK2 protein expression, which increases P53 protein expression via the down-regulation of BRE.

Conclusions

Our studies demonstrated that over-expression of HOTTIP promotes cell apoptosis and inhibits cell growth in U118-MG and U87-MG human glioma cell lines by down-regulating BRE expression to regulate the expression of P53, CDK2 and Cyclin A proteins. The data described in this study indicate that HOTTIP is an interesting candidate for further functional studies in glioma and demonstrate the potential application of HOTTIP in glioma therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0431-y) contains supplementary material, which is available to authorized users.

Regulation of PCGEM1 by p54/nrb in prostate cancer

PCGEM1 is a long non-coding RNA (lncRNA) that is often upregulated in prostate cancer. However, little is known how PCGEM1 is regulated. In the present study, we show transcriptional regulation of PCGEM1 in response to androgen deprivation by p54/nrb. While ectopic expression of p54/nrb increases, suppression of p54/nrb by RNAi or knockout (KO) reduces PCGEM1. Moreover, rescue experiments indicate that re-expression of p54/nrb in KO cells restores the ability to induce PCGEM1, leading to upregulation of the androgen receptor splice variant AR3 which has been shown to play a role in castration resistance. Finally, 3,3′-Diindolylmethane (DIM), a known chemoprevention agent, is capable of suppressing PCGEM1 expression by preventing the interaction of p54/nrb with the PCGEM1 promoter. In particular, DIM reduces tumor growth by suppression of PCGEM1 and promoting apoptosis in the castrated xenograft mouse model. Together, these results demonstrate a novel mechanism of p54/nrb-mediated expression of PCGEM1 and AR3, contributing to castration resistance in prostate cancer.

CUDR promotes liver cancer stem cell growth through upregulating TERT and C-Myc

Cancer up-regulated drug resistant (CUDR) is a novel non-coding RNA gene. Herein, we demonstrate excessive CUDR cooperates with excessive CyclinD1 or PTEN depletion to accelerate liver cancer stem cells growth and liver stem cell malignant transformation in vitro and in vivo. Mechanistically, we reveal the decrease of PTEN in cells may lead to increase binding capacity of CUDR to CyclinD1. Therefore, CUDR-CyclinD1 complex loads onto the long noncoding RNA H19 promoter region that may lead to reduce the DNA methylation on H19 promoter region and then to enhance the H19 expression. Strikingly, the overexpression of H19 increases the binding of TERT to TERC and reduces the interplay between TERT with TERRA, thus enhancing the cell telomerase activity and extending the telomere length. On the other hand, insulator CTCF recruits the CUDR-CyclinD1 complx to form the composite CUDR-CyclinD1-insulator CTCF complex which occupancied on the C-myc gene promoter region, increasing the outcome of oncogene C-myc. Ultimately, excessive TERT and C-myc lead to liver cancer stem cell and hepatocyte-like stem cell malignant proliferation. To understand the novel functions of long noncoding RNA CUDR will help in the development of new liver cancer therapeutic and diagnostic approaches.

Analysis of long non-coding RNA expression profiles in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive and lethal malignancies. Long non-coding RNAs (lncRNAs) are a novel class of non-protein-coding transcripts that have been implicated in cancer biogenesis and prognosis. By repurposing microarray probes, we herein analysed the lncRNA expression profiles in two public PDAC microarray datasets and identified 34 dysregulated lncRNAs in PDAC. In addition, the expression of 6 selected lncRNAs was confirmed in Ren Ji cohort and pancreatic cell lines, and their association with 80 PDAC patients' clinicopathological features and prognosis was investigated. Results indicated that AFAP1-AS1, UCA1 and ENSG00000218510 might be involved in PDAC progression and significantly associated with overall survival of PDAC. UCA1 and ENSG00000218510 expression status may serve as independent prognostic biomarkers for overall survival of PDAC. Gene set enrichment analysis (GSEA) analysis suggested that high AFAP1-AS1, UCA1 and low ENSG00000218510 expression were correlated with several tumorigenesis related pathways. Functional experiments demonstrated that AFAP1-AS1 and UCA1 were required for efficient invasion and/or proliferation promotion in PDAC cell lines, while ENSG00000218510 acted the opposite. Our findings provide novel information on lncRNAs expression profiles which might be beneficial to the precise diagnosis, subcategorization and ultimately, the individualized therapy of PDAC.

The emerging role of long non-coding RNAs in endometrial cancer

The human genome is pervasively transcribed and approximately 98% of the genome is non-coding. Long non-coding RNAs (lncRNAs) are a heterogeneous group of RNA transcripts that are >200 nucleotides in length with minimal to no protein-coding potential. Similar to proteins, lncRNAs have important biological functions in both normal cells and disease states including many types of cancer. This review summarizes recent advances in our understanding of lncRNAs in cancer biology and highlights the potential for lncRNA as diagnostic biomarkers and therapeutics. Herein we focus on the poorly understood role of lncRNAs in endometrial cancer, the most common gynecologic malignancy in the developed world.

Current Status of Long Non-Coding RNAs in Human Breast Cancer

Breast cancer represents a major health burden in Europe and North America, as recently published data report breast cancer as the second leading cause of cancer related death in women worldwide. Breast cancer is regarded as a highly heterogeneous disease in terms of clinical course and biological behavior and can be divided into several molecular subtypes, with different prognosis and treatment responses. The discovery of numerous non-coding RNAs has dramatically changed our understanding of cell biology, especially the pathophysiology of cancer. Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts >200 nucleotides in length. Several studies have demonstrated their role as key regulators of gene expression, cell biology and carcinogenesis. Deregulated expression levels of lncRNAs have been observed in various types of cancers including breast cancer. lncRNAs are involved in cancer initiation, progression, and metastases. In this review, we summarize the recent literature to highlight the current status of this class of long non-coding lncRNAs in breast cancer.

Long non-coding RNA ROR promotes proliferation, migration and chemoresistance of nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is one of the most common malignancies of the head and neck. It arises from the nasopharynx epithelium and is associated with high morbidity and mortality. Long non‐coding RNA (lncRNA) have been reported to regulate gene interaction and play critical roles in carcinogenesis and progression. LncRNA‐ROR, a recently identified lncRNA, has been shown to be involved in initiation, progression and metastasis of several tumors, including hepatocellular carcinoma, breast cancer and glioma. However, whether lncRNA‐ROR is associated with the progression of NPC remains unknown. Resistance to radiotherapy and chemotherapy is the primary cause of NPC patients’ death. In this study, we found that lncRNA‐ROR was significantly upregulated in NPC tissues compared with normal tissues. Next, our study proved that lncRNA‐ROR was highly associated with the proliferation, metastasis and apoptosis of NPC. The enrichment of lncRNA‐ROR played a critucal functional role in chemoresistance. The mechanism by which NPC resists chemotherapy might be that lncRNA‐ROR suppress p53 signal pathway. Taken together, these data suggested that lncRNA‐ROR played an important role in the progression of NPC; thereby it might become a therapeutic target and reduce chemoresistance for NPC.

Long non-coding RNA UCA1 promotes the tumorigenesis in pancreatic cancer

The contribution of long non-coding RNAs (lncRNAs) to tumorigenesis and metastasis of pancreatic cancer (PC) remains largely unknown. Urothelial cancer-associated 1 (UCA1), which is an originally identified lncRNA in bladder cancer, has be proved to play a pivotal role in bladder cancer progression and embryonic development. In this study, we detected the mRNA expression of UCA1 in 128 PC patients by qRT-PCR, and found that UCA1 expression was significantly, up-regulated in tumor tissues than that in matched adjacent non-tumor tissues (p<0.05). Clinicopathological analysis demonstrated that UCA1 expression in PC significantly correlated with malignant potential factors such as tumor size (p=0.021), depth of invasion (p=0.033), CA19-9 level (p=0.034) and tumor stage (p=0.013). Cox proportional hazards regression analysis also confirmed that high UCA1 expression was an independent prognostic biomarker of PC (p=0.046), which led to an obviously shorter 5-year overall survival (OS) compared to those patients with low UCA1 expressions (p=0.018). Furthermore, we effectively down-regulated UCA1 mRNA expression by transfecting RNA interfere fragments into SW-1990 cells, and our results in vitro indicated that down-regulation of UCA1 could effectively inhibit the cell proliferative activities, induce apoptotic rate and cause cell cycle arrest in PC cells (p<0.05). Meanwhile, UCA1 expression negative-correlated with p27 in PC tissues (r²=0.46, p<0.01), and knockdown of p27 partly abrogated the cell proliferative activities caused by UCA1 (p<0.05). Our results raised the possibility of using UCA1 as a potential prognostic biomarker and therapy target of PC, and down-regulation of UCA1 might be considered to be a novel molecular treatment strategy for patients with PC.

Regulation of breast tumorigenesis through acid sensors

The low extracellular pH in the microenvironment has been shown to promote tumor growth and metastasis; however, the underlying mechanism is poorly understood. Particularly, little is known how the tumor cell senses the acidic signal to activate the acidosis-mediated signaling. In this study, we show that breast cancer cells express acid-sensing ion channel 1 (ASIC1), a proton-gated cation channel primarily expressed in the nervous system. RNA interference, knockout and rescue experiments demonstrate a critical role for ASIC1 in acidosis-induced reactive oxidative species and NF-κB activation, two key events for tumorigenesis. Mechanistically, ASIC1 is required for acidosis-mediated signaling through calcium influx. We show that as a cytoplasmic membrane protein, ASIC1 is also associated with mitochondria, suggesting that ASIC1 may regulate mitochondrial calcium influx. Importantly, interrogation of the Cancer Genome Atlas breast invasive carcinoma data set indicates that alterations of ASIC1 alone or combined with other 4 ASIC genes are significantly correlated with poor patient survival. Furthermore, ASIC1 inhibitors cause a significant reduction of tumor growth and tumor load. Together, these results suggest that ASIC1 contributes to breast cancer pathogenesis in response to acidic tumor microenvironments, and ASIC1 may serve as a prognostic marker and a therapeutic target for breast cancer.

Mechanisms of breast cancer resistance to anthracyclines or taxanes: an overview of the proposed roles of noncoding RNA

PURPOSE OF REVIEW

Anthracyclines and taxanes are the two most active classes of cytotoxic agents that are commonly used for the treatment of breast cancer. However, resistance to these agents has become a major clinical obstacle. The aim of the present review is to define the roles of noncoding RNA (ncRNA) in breast cancer progression and the development of chemotherapy resistance. The ultimate goal is to exploit ncRNAs as new therapeutic tools to overcome resistance.

RECENT FINDINGS

Two important types of ncRNA include microRNA (miRNA) and long noncoding RNA (lncRNA). Both miRNA and lncRNA have recently impacted the field of breast cancer research as important pieces in the mechanistic puzzle of the genes and pathways involved in breast cancer development and progression.

SUMMARY

Herein, we review the roles of miRNA and lncRNA in breast cancer progression and the development of chemotherapy resistance. Future research should include identification of ncRNAs that could be potential therapeutic targets in chemotherapy-resistant tumors, as well as ncRNA biomarkers that facilitate more tumor-specific treatment options for chemotherapy-resistant breast cancer patients.

Association of long noncoding RNA and c-JUN expression in hepatocellular carcinoma

BACKGROUND

Long noncoding RNAs(lncRNAs) have emerged as key elements in modulating gene expression in different biological contexts.

PATIENTS AND METHODS

We used quantitative real-time PCR (Qpcr) to evaluate the expression of lncRNA-UCA1 and C-JUN in serum of 70 patients with hepatocellular carcinoma (HCC), 32 patients chronic hepatitis C (CHC) and 38 healthy subjects and their correlation with different clinicopathological factors.

RESULTS

The expression of lncRNA-UCA1 and C-JUN was positive in 91.4%HCC patients with strong discriminating power between HCC and healthy subjects and CHC patients as well. The median follow up period was 29 months. The survival analysis showed that both lncRNA-UCA1 and C-JUN were independent prognostic factors. Of note, we identified C-JUN expression changes consistent with the lncRNA-UCA1 target regulation.

CONCLUSION

This information sheds light on the possible role of lncRNA-UCA1 and C-JUN mRNA as promising diagnostic and prognostic markers as well as potential therapeutic targets in HCC.

Long non-coding RNAs in cancer drug resistance development

The presence or emergence of chemoresistance in tumor cells is a major burden in cancer therapy. While drug resistance is a multifactorial phenomenon arising from altered membrane transport of drugs, altered drug metabolism, altered DNA repair, reduced apoptosis rate and alterations of drug metabolism, it can also be linked to genetic and epigenetic factors. Long non-coding RNAs (lncRNAs) have important regulatory roles in many aspects of genome function including gene transcription, splicing, and epigenetics as well as biological processes involved in cell cycle, cell differentiation, development, and pluripotency. As such, it may not be surprising that some lncRNAs have been recently linked to carcinogenesis and drug resistance/sensitivity. Research is accelerating to decipher the exact molecular mechanism of lncRNA-regulated drug resistance and its therapeutic implications. In this article, we will review the structure, biogenesis, and mode of action of lncRNAs. Then, the involvement of lncRNAs in drug resistance will be discussed in detail.

Long noncoding RNA EGOT negatively affects the antiviral response and favors HCV replication

The role of long noncoding RNAs (lncRNAs) in viral infection is poorly studied. We have identified hepatitis C virus (HCV)-Stimulated lncRNAs (CSRs) by transcriptome analysis. Interestingly, two of these CSRs (PVT1 and UCA1) play relevant roles in tumorigenesis, providing a novel link between HCV infection and development of liver tumors. Expression of some CSRs seems induced directly by HCV, while others are upregulated by the antiviral response against the virus. In fact, activation of pathogen sensors induces the expression of CSR32/EGOT RIG-I and the RNA-activated kinase PKR sense HCV RNA, activate NF-κB and upregulate EGOT EGOT is increased in the liver of patients infected with HCV and after infection with influenza or Semliki Forest virus (SFV). Genome-wide guilt-by-association studies predict that EGOT may function as a negative regulator of the antiviral pathway. Accordingly, EGOT depletion increases the expression of several interferon-stimulated genes and leads to decreased replication of HCV and SFV Our results suggest that EGOT is a lncRNA induced after infection that increases viral replication by antagonizing the antiviral response.

C/EBPα-p30 protein induces expression of the oncogenic long non-coding RNA UCA1 in acute myeloid leukemia

Accumulating evidences indicate that different long non-coding RNAs (lncRNAs) might play a relevant role in tumorigenesis, with their expression and function already associated to cancer development and progression. CCAAT/enhancer-binding protein-α (CEBPA) is a critical regulator of myeloid differentiation whose inactivation contributes to the development of acute myeloid leukemia (AML). Mutations in C/EBPα occur in around 10% of AML cases, leading to the expression of a 30-kDa dominant negative isoform (C/EBPα-p30). In this study, we identified the oncogenic urothelial carcinoma associated 1 (UCA1) lncRNA as a novel target of the C/EBPα-p30. We show that wild-type C/EBPα and C/EBPα-p30 isoform can bind the UCA1 promoter but have opposite effects on UCA1 expression. While wild-type C/EBPα represses, C/EBPα-p30 can induce UCA1 transcription. Notably, we also show that UCA1 expression increases in cytogenetically normal AML cases carrying biallelic CEBPA mutations. Furthermore, we demonstrate that UCA1 sustains proliferation of AML cells by repressing the expression of the cell cycle regulator p27^kip1. Thus, we identified, for the first time, an oncogenic lncRNA functioning in concert with the dominant negative isoform of C/EBPα in AML.

Upregulated lncRNA-UCA1 contributes to progression of hepatocellular carcinoma through inhibition of miR-216b and activation of FGFR1/ERK signaling pathway

The long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) has been recently shown to be dysregulated, which plays an important role in the progression of several cancers. However, the biological role and clinical significance of UCA1 in the carcinogenesis of hepatocellular carcinoma (HCC) remain unclear. Herein, we found that UCA1 was aberrantly upregulated in HCC tissues and associated with TNM stage, metastasis and postoperative survival. UCA1 depletion inhibited the growth and metastasis of HCC cell lines in vitro and in vivo. Furthermore, UCA1 could act as an endogenous sponge by directly binding to miR-216b and downregulation miR-216b expression. In addition, UCA1 could reverse the inhibitory effect of miR-216b on the growth and metastasis of HCC cells, which might be involved in the derepression of fibroblast growth factor receptor 1 (FGFR1) expression, a target gene of miR-216b, and the activation of ERK signaling pathway. Taken together, our data highlights the pivotal role of UCA1 in the tumorigenesis of HCC. Moreover, the present study elucidates a novel lncRNA-miRNA-mRNA regulatory network that is UCA1-miR-216b-FGFR1-ERK signaling pathway in HCC, which may help to lead a better understanding the pathogenesis of HCC and probe the feasibility of lncRNA-directed diagnosis and therapy for this deadly disease.

Long noncoding RNA expression profile analysis of colorectal cancer and metastatic lymph node based on microarray data

Long noncoding RNAs (lncRNAs) are emerging as an important part of biological progress in cancers, yet the aberrant lncRNAs implicated in colorectal cancer (CRC) with lymph node metastasis remain unknown. In this study, a total of 390 lncRNA transcripts and 508 mRNA transcripts were dysregulated in tumor tissues compared with paired metastatic lymph nodes. Functional prediction showed that lots of lncRNAs might be involved in biological pathways related to CRC metastasis by cis-regulation and trans-regulation of coexpressed genes. As a representative, ENST00000430471 was associated with cell proliferation and invasion of CRC cells. These results provided support for further investigations of the metastatic pathogenesis of CRC.

Long non-coding RNAs: An emerging powerhouse in the battle between life and death of tumor cells

Long non-coding RNAs (lncRNAs) represent a class of non-protein coding transcripts longer than 200 nucleotides that have aptitude for regulating gene expression at the transcriptional, post-transcriptional or epigenetic levels. In recent years, lncRNAs, which are believed to be the largest transcript class in the transcriptomes, have emerged as important players in a variety of biological processes. Notably, the identification and characterization of numerous lncRNAs in the past decade has revealed a role for these molecules in the regulation of cancer cell survival and death. It is likely that this class of non-coding RNA constitutes a critical contributor to the assorted known or/and unknown mechanisms of intrinsic or acquired drug resistance. Moreover, the expression of lncRNAs is altered in various patho-physiological conditions, including cancer. Therefore, lncRNAs represent potentially important targets in predicting or altering the sensitivity or resistance of cancer cells to various therapies. Here, we provide an overview on the molecular functions of lncRNAs, and discuss their impact and importance in cancer development, progression, and therapeutic outcome. We also provide a perspective on how lncRNAs may alter the efficacy of cancer therapy and the promise of lncRNAs as novel therapeutic targets for overcoming chemoresistance. A better understanding of the functional roles of lncRNA in cancer can ultimately translate to the development of novel, lncRNA-based intervention strategies for the treatment or prevention of drug-resistant cancer.

LncRNA-UCA1 enhances cell proliferation and 5-fluorouracil resistance in colorectal cancer by inhibiting miR-204-5p

Recent preliminary studies reported the in vitro tumor-promoting effects of long non-coding RNA urothelial carcinoma associated 1 (UCA1) in colorectal cancer (CRC). However, the in vivo functions and molecular mechanism of UCA1 in CRC remain unclear. Therefore, we investigated the detailed role and mechanism of UCA1 in CRC. We found that UCA1 was up-regulated in CRCs and negatively correlated with survival time in two CRC cohorts. Functional assays revealed the in vitro and in vivo growth-promoting function of UCA1 and revealed that UCA1 can decrease the sensitivity of CRC cells to 5-FU by attenuating apoptosis. Further mechanistic studies revealed that UCA1 could sponge endogenous miR-204-5p and inhibit its activity. We also identified CREB1 as a new target of miR-204-5p. The protein levels of CREB1 were significantly up-regulated in CRCs, negatively associated with survival time and positively correlated with the UCA1 expression. The present work provides the first evidence of a UCA1-miR-204-5p-CREB1/BCL2/RAB22A regulatory network in CRC and reveals that UCA1 and CREB1 are potential new oncogenes and prognostic factors for CRC.

HBx-upregulated lncRNA UCA1 promotes cell growth and tumorigenesis by recruiting EZH2 and repressing p27Kip1/CDK2 signaling

It is well accepted that HBx plays the major role in hepatocarcinogenesis associated with hepatitis B virus (HBV) infections. However, little was known about its role in regulating long noncoding RNAs (lncRNAs), a large group of transcripts regulating a variety of biological processes including carcinogenesis in mammalian cells. Here we report that HBx upregulates UCA1 genes and downregulates p27 genes in hepatic LO2 cells. Further studies show that the upregulated UCA1 promotes cell growth by facilitating G1/S transition through CDK2 in both hepatic and hepatoma cells. Knock down of UCA1 in HBx-expressing hepatic and hepatoma cells resulted in markedly increased apoptotic cells by elevating the cleaved caspase-3 and caspase-8. More importantly, UCA1 is found to be physically associated with enhancer of zeste homolog 2 (EZH2), which suppresses p27Kip1 through histone methylation (H3K27me3) on p27Kip1 promoter. We also show that knockdown of UCA1 in hepatoma cells inhibits tumorigenesis in nude mice. In a clinic study, UCA1 is found to be frequently up-regulated in HBx positive group tissues in comparison with the HBx negative group, and exhibits an inverse correlation between UCA1 and p27Kip1 levels. Our findings demonstrate an important mechanism of hepatocarcinogenesis through the signaling of HBx-UCA1/EZH2-p27Kip1 axis, and a potential target of HCC.

LncRNA BCAR4 wires up signaling transduction in breast cancer

Long noncoding RNAs (lncRNAs) are dysregulated in many cancer types and are believed to play crucial roles in regulating several hallmarks of cancer biology. Currently, most studies support the concept that lncRNAs are involved in either transcriptional or post-transcriptional processes via binding/targeting epigenetic modifiers or hRNP complexes. The discovery of new biological functions of lncRNA and novel RNA binding proteins suggests that lncRNAs may be implicated in a broad spectrum of biological processes such as signal transduction, allosteric regulation of cytoplasmic enzymatic activities, among other potential processes. In a recent report that we have made, based on open-ended lncRNA pulldown technology and a series of systematic analyses, we suggest that lncRNAs also play critical roles in the regulation of noncanonical Hedgehog/GLI 2 signal transduction pathways in cancer cells, which further broadens the scope of known lncRNA functions and aids in the discovery and design of more effective and evidence-based therapeutic targets for the treatment of human cancers and other diseases.

Microarray expression profiling of dysregulated long non-coding RNAs in triple-negative breast cancer

Triple-negative breast cancer (TNBC) represents a collection of malignant breast tumors that are often aggressive and have an increased risk of metastasis and relapse. Long non-coding RNAs are generally defined as RNA transcripts measuring 200 nucleotides or longer that do not encode for any protein. During the past decade, increasing evidence has shown that lncRNAs play important roles in oncogenesis and tumor suppression; however, the roles of lncRNAs in TNBC are poorly understood. To address this issue, we used Agilent human lncRNA microarray chips and bioinformatics tools, including Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG), to assess lncRNA expression in 3 pairs of TNBC tissues. A dysregulated lncRNA expression profile was identified by microarray and verified by qRT-PCR in 48 pairs of breast cancer subtype tissues. Metastasis is the major cause of cancer-related deaths, including those in TNBC, and the presence of dormant residual disseminated tumor cells (DTC) may be a key factor leading to metastasis. ANKRD30A, a potential target for breast cancer immunotherapy, is currently one of the most used DTC markers. Notably, we found the expression levels of the novel intergenic lncRNA LINC00993 to be associated with the expression levels of ANKRD30A. Furthermore, our qRT-PCR data indicated that the expression of LINC00993 was also associated with the expression of the estrogen receptor. In conclusion, our study identified a set of lncRNAs that were consistently aberrantly expressed in TNBC, and these dysregulated lncRNAs may be involved in the development and/or progression of TNBC.

From junk to master regulators of invasion: lncRNA functions in migration, EMT and metastasis

Metastasis is a multistep process that involves the dissemination of cells from the primary tumor and colonization of distant secondary organs. Epithelial cells at the invasive front of a carcinoma acquire an enhanced migratory phenotype in a process called epithelial-to-mesenchymal transition (EMT). This cellular plasticity seems to drive the initiation of metastasis. Identifying important molecules and understanding their molecular mechanisms is a key to cancer prognosis and the development of therapeutics for late stage malignancies. Recent advances in sequencing technology uncovered that the mammalian genome is pervasively transcribed into many nonprotein-coding RNAs including the class of long noncoding RNA, a.k.a. lncRNA. Several lncRNAs are differentially expressed in carcinomas and they are emerging as potent regulators of tumor progression and metastasis. Here, we review the diverse molecular mechanisms, cellular roles and regulatory patterns that are becoming apparent for the noncoding transcriptome. Chromatin modification, epigenetic regulation, alternative splicing and translational control by MALAT1, HOTAIR and TRE lncRNAs represent important examples of lncRNA-mediated control of cell migration and invasion, EMT and metastasis. Beyond these better characterized examples, numerous additional transcripts have been associated with cancer metastasis, but their functional roles await their discovery.

Identification of long-non coding RNA UCA1 as an oncogene in renal cell carcinoma

Renal cell carcinoma (RCC) is the most common type of kidney cancer in adults, which is associated with poor prognosis and high recurrence. Long non‑coding RNAs (lncRNAs) have been reported to be dysregulated in cancer and to be important in the regulation of carcinogenesis, thus suggesting that this class of molecules may be used as biomarkers in cancer. The lncRNA urothelial carcinoma associated 1 (UCA1) has been observed to be upregulated and to function as an oncogene in certain types of cancer; however, the role of UCA1 in RCC remains to be elucidated. The present study aimed to determine the expression and function of UCA1 in RCC. Quantitative polymerase chain reaction (qPCR) was used to determine the expression levels of UCA1 in 46 paired RCC and adjacent normal tissue samples. Furthermore, qPCR was used to determine the expression levels of UCA1 in four RCC cell lines compared with the human embryonic kidney 293T cell line. The impact of UCA1 on cell migration, proliferation and apoptosis was investigated by wound scratch assay, MTT and flow cytometry, respectively. The results of the present study demonstrated that UCA1 expression levels were significantly increased in RCC tissues and cells, as compared with the controls. Ectopic expression and gene silencing of UCA1 in RCC cell lines exerted opposite effects on cellular proliferation, migration and apoptosis, and the results suggested that UCA1 may function as an oncogene in RCC. These results indicated that UCA1 may be considered as a promising biomarker for diagnosis, and a therapeutic target in RCC. Further research is required to elucidate the role and target genes of UCA1 in RCC.

UCA1 functions as a competing endogenous RNA to suppress epithelial ovarian cancer metastasis

Urothelial cancer associated 1 (UCA1) is an example of functional long noncoding RNAs involved in many biologic processes. However, little is known about the association between UCA1 expression and metastasis in epithelial ovarian cancer (EOC). Findings of this study confirmed that not only UCA1 was aberrantly upregulated in EOC tissues and cells, but also correlated with status of lymph node metastasis and FIGO stage. Furthermore, univariate and multivariate analyses showed that UCA1 was a prognostic factor for overall survival in EOC patients. In vitro, knockdown of UCA1 reduced the invasion and migration ability of EOC cells. The results showed that UCA1 could function as an endogenous sponge by directly binding to miR-485-5p. Depletion of UCA1 was involved in the downregulation of matrix metallopeptidase 14 (MMP14) expression, a target gene of miR-485-5p. In conclusion, our work indicates that UCA1 is a new prognostic biomarker for EOC, establishing a novel connection among UCA1, miR-485-5p, and MMP14 in EOC metastasis.

Circulating Long Noncoding RNA UCA1 as a Novel Biomarker of Acute Myocardial Infarction

Acute myocardial infarction (AMI) is the most serious cardiovascular disease with high morbidity and mortality. Recent studies have showed that long noncoding RNAs (lnc RNA) play important roles in pathophysiology of cardiovascular diseases, but the investigations are still in their infancy. An lnc RNA named urothelial carcinoma-associated 1 (UCA1) is found in tumors such as bladder cancers and lung cancer. And the UCA1 could be as a predictive biomarker for bladder cancer in urine samples or lung cancer in plasma, respectively. In normal states, UCA1 is specifically expressed in heart of adult, indicating that UCA1 might be as a biomarker for heart diseases such as AMI. To test the speculation, we detect the level of UCA1 in plasma of AMI patients and health control using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). In addition, we also test the level of miR-1 as it is reported to regulate the expression of UCA1. The results show that the level of plasma UCA1 is decreased at the early state of AMI patients and increased at day 3 after AMI. In addition, the UCA1 alteration is inversely associated with the expression of miR-1. These findings indicate that the circulating UCA1 could be used as a promising novel biomarker for the diagnosis and/or prognosis of AMI.