LncRNA HOTAIR: A master regulator of chromatin dynamics and cancer. Biochim Biophys Acta Rev Cancer. 2015;1856:151-164. [PMID: 26208723 DOI: 10.1016/j.bbcan.2015.07.001]

Association of lncRNA SH3PXD2A-AS1 with preeclampsia and its function in invasion and migration of placental trophoblast cells

Accumulating evidence suggests that the pathogenesis of preeclampsia involves poor placentation caused by insufficient trophoblast invasion and impaired uterine spiral artery remodeling, yet the underlying molecular mechanism remains unclear. We carried out transcriptome profiling on placentae from preeclamptic patients and normal subjects, and identified about four hundred long non-coding RNAs differentially expressed in placentae of patients with early-onset severe preeclampsia. Here, we report our identification of lncRNA SH3PXD2A-AS1 as a potential causal factor for this disease and its downstream pathways involved in placentation. We found that expression level of SH3PXD2A-AS1 in the placentae is positively correlated with clinical severity of the patients. We demonstrated that SH3PXD2A-AS1 inhibited invasion and migration through recruiting CCCTC-binding factor (CTCF) to the promoters of SH3PXD2A and CCR7 to inhibit their transcription. Therefore, we conclude that the upregulation of lncRNA SH3PXD2A-AS1 may contribute to the pathogenesis of preeclampsia through prohibiting trophoblast invasion during placentation.

A long non-coding RNA, HOTAIR, promotes cartilage degradation in osteoarthritis by inhibiting WIF-1 expression and activating Wnt pathway

BACKGROUND

Long noncoding RNAs (lncRNAs) are recently found to be critical regulators of the epigenome. However, our knowledge of their role in osteoarthritis (OA) development is limited. This study investigates the mechanism by which HOTAIR, a key lncRNA with elevated expression in OA, affects OA disease progression.

RESULTS

HOTAIR expression was greatly elevated in osteoarthritic compared to normal chondrocytes. Silencing and over-expression of HOTAIR in SW1353 cells respectively reduced and increased the expression of genes associated with cartilage degradation in OA. Investigation of molecular pathways revealed that HOTAIR acted directly on Wnt inhibitory factor 1 (WIF-1) by increasing histone H3K27 trimethylation in the WIF-1 promoter, leading to WIF-1 repression that favours activation of the Wnt/β-catenin pathway.

CONCLUSIONS

Activation of Wnt/β-catenin signalling by HOTAIR through WIF-1 repression in osteoarthritic chondrocytes increases catabolic gene expression and promotes cartilage degradation. This is the first study to demonstrate a direct link between HOTAIR, WIF-1 and OA progression, which may be useful for future investigations into disease biomarkers or therapeutic targets.

Long non-coding RNA SNGH7 Is activated by SP1 and exerts oncogenic properties by interacting with EZH2 in ovarian cancer

Long non-coding RNAs (lncRNAs) are key regulators or a range of diseases and chronic conditions such as cancers, but how they function in the context of ovarian cancer (OC) is poorly understood. The Coding-Potential Assessment Tool was used to assess the likely protein-coding potential of SNHG7. SNHG7 expression was elevated in ovarian tumour tissues measured by qRT-PCR. The online database JASPAR was used to predict the transcription factors binding to SNHG7. Twenty-four-well Transwell plates were used for invasion assays. RNA immunoprecipitation was performed to determine RNA-protein associations. EdU assay was introduced to detect cell proliferation. Chromatin immunoprecipitation was performed to confirm the directly interaction between DNA and protein. We discovered that in the context of OC there is a significant up-regulation of the lncRNA SNHG7. Knocking down this lncRNA disrupted both OC cell invasion and proliferation, while its overexpression had the opposite effect. SP1 binding sites were present in the SNHG7 promoter, and chromatin immunoprecipitation (ChIP) confirmed direct SP1 binding to this region, activating SNHG7 transcription. We found that at a mechanistic level in OC cells, KLF2 is a probable SNHG7 target, as we found that SHNCCC16 directly interacts with EZH2 and thus represses KLF2 expression. In summary, this research demonstrates that lncRNA SNHG7 is an SP1-activated molecule that contributes to OC progression by providing a scaffold whereby EZH2 can repress KLF2 expression.

New twists on long noncoding RNAs: from mobile elements to motile cancer cells

The purpose of this review is to highlight several areas of lncRNA biology and cancer that we hope will provide some new insights for future research. These include the relationship of lncRNAs and the epithelial to mesenchymal transition (EMT) with a focus on transcriptional and alternative splicing mechanisms and mRNA stability through miRNAs. In addition, we highlight the potential role of enhancer e-lncRNAs, the importance of transposable elements in lncRNA biology, and finally the emerging area of using antisense oligonucleotides (ASOs) and small molecules to target lncRNAs and their therapeutic implications.

LncRNA PVT1 promotes exosome secretion through YKT6, RAB7, and VAMP3 in pancreatic cancer

Pancreatic cancer (PC) is one of the deadliest cancers worldwide. Cancer cells secrete excessive numbers of exosomes that play essential roles in tumorigenesis. Long non-coding RNAs (lncRNAs) are essential non-coding RNAs for cancer progression. However, the role of lncRNA plasmacytoma variant translocation 1 (PVT1) in exosome secretion of PC remains to be comprehensively investigated. Thus, nanoparticle tracking analysis and transmission electron microscopy were performed to determine exosome secretion. Confocal microscopy, western blots, real-time PCR, immunofluorescence, pull-down and RNA immunoprecipitation assays, and rescue experiments were applied to investigate the mechanism underlying the role of PVT1 in exosome secretion. The results showed that PVT1 was upregulated in PC cells, along with increased levels of YKT6 v-SNARE homolog (YKT6), ras-related protein Rab-7 (RAB7), and vesicle-associated membrane protein 3 (VAMP3). Also, PVT1 promoted the transportation of multivesicular bodies (MVBs) towards the plasma membrane. In addition, PVT1 promoted the docking of MVBs by altering RAB7 expression and localization. Moreover, PVT1 promoted the fusion of MVBs with the plasma membrane through regulating YKT6 and VAMP3 colocalization and the palmitoylation of YKT6. Taken together, the results suggest that PVT1 promoted exosome secretion of PC cells and thus, can expand the understanding of PVT1 in tumor biology.

Pan-cancer analysis reveals the role of long non-coding RNA LINC01614 as a highly cancer-dependent oncogene and biomarker

Long intergenic non-coding RNA 1614 (LINC01614) is highly expressed in several malignant tumor types, suggesting that it may act as an oncogene. However, the specific roles of LINC01614 in malignant tumors have remained elusive. To examine the expression pattern of LINC01614 in various malignancies, a comprehensive pan-cancer analysis was performed using public databases, including 53 normal tissue types and 32 cancer datasets with samples from 9,091 patients. The results were validated using reverse transcription-quantitative PCR analysis of tissue specimens from patients. LINC01614 expression was upregulated in most malignant tumors, thus demonstrating diagnostic potential. Furthermore, upregulation of LINC01614 was associated with poor overall survival in the majority of cases. However, the association with clinical outcome was highly cancer-dependent; LINC01614 appeared to be an oncogene and diagnostic/prognostic biomarker in cancers of the digestive, respiratory, nervous and endocrine systems, as well as breast and head and neck cancer, but not in the cancers of the reproductive system or some of the urinary system. High LINC01614 expression was also markedly associated with the epithelial-mesenchymal transition (EMT) and associated signaling pathways. Overall, the present results suggest that LINC01614 is an EMT-associated oncogene that influences the metastasis and prognosis of several cancers, thus highlighting its potential as a novel diagnostic and prognostic marker.

Long non-coding RNA FAM66C is associated with clinical progression and promotes cell proliferation by inhibiting proteasome pathway in prostate cancer

Prostate cancer is the most prevalent malignancy in men, and the identification of novel oncogenes is clinically valuable for early screening, prevention and treatment. Recently, the studies have revealed that long non-coding RNAs (lncRNAs) play important roles in the development and progression of cancers including prostate cancer. The present study aims to identify a novel lncRNA that correlated with the survival time of prostate cancer patients and try to explore its biological functions in prostate cancer cells. After analysing the prostate carcinoma dataset of the Cancer Genome Atlas (TCGA), the lncRNA FAM66C was screened with its expression highly correlated with patient survival time, tumour stage and Gleason pattern. Real-time PCR showed that FAM66C highly expressed in prostate cancer cells, and knockdown FAM66C by siRNAs resulted in significant inhibition of cell growth. Furthermore, the results indicated that FAM66C promoted cell growth due to increasing cell proliferation but not decreasing cell apoptosis. In addition, FAM66C activated the epidermal growth factor receptor (EGFR)-extracellular signal-regulated kinase (ERK) signalling to promote cell proliferation. The result of Western Blotting and lysosomal acidity detection showed that knockdown FAM66C increased the protein ubiquitination and the lysosomal acidity. Moreover, inhibition of proteasome pathway could increase the activation of EGFR-ERK signalling and cell proliferation. Taken together, these results suggested that lncRNA FAM66C activate EGFR-ERK signalling to promote cell proliferation by inhibiting proteasome pathway in prostate cancer. SIGNIFICANCE OF THE STUDY: We demonstrated that lncRNA FAM66C was associated with clinical progression. In addition, highly expressed lncRNA FAM66C in prostate cancer cell lines promoted cell proliferation. Moreover, lncRNA FAM66C activate the epidermal growth factor receptor (EGFR)-extracellular signal-regulated kinase (ERK) signalling to promote cell proliferation by inhibiting proteasome pathway in prostate cancer. This study might provide lncRNA FAM66C as a potential therapeutic target gene of prostate cancer.

Beyond MicroRNAs: Emerging Role of Other Non-Coding RNAs in HPV-Driven Cancers

Persistent infection with high-risk Human Papilloma Virus (HPV) leads to the development of several tumors, including cervical, oropharyngeal, and anogenital squamous cell carcinoma. In the last years, the use of high-throughput sequencing technologies has revealed a number of non-coding RNA (ncRNAs), distinct from micro RNAs (miRNAs), that are deregulated in HPV-driven cancers, thus suggesting that HPV infection may affect their expression. However, since the knowledge of ncRNAs is still limited, a better understanding of ncRNAs biology, biogenesis, and function may be challenging for improving the diagnosis of HPV infection or progression, and for monitoring the response to therapy of patients affected by HPV-driven tumors. In addition, to establish a ncRNAs expression profile may be instrumental for developing more effective therapeutic strategies for the treatment of HPV-associated lesions and cancers. Therefore, this review will address novel classes of ncRNAs that have recently started to draw increasing attention in HPV-driven tumors, with a particular focus on ncRNAs that have been identified as a direct target of HPV oncoproteins.

Long Non-Coding RNA HOTAIR in Breast Cancer Therapy

Breast cancer (BC) is the most common cancer type among women, and morbidity and mortality rates are still very high. Despite new innovative therapeutic approaches for all BC molecular subtypes, the discovery of new molecular biomarkers involved in tumor progression has been fundamental for the implementation of personalized treatment strategies and improvement of patient management. Many experimental studies indicate that long non-coding RNAs (lncRNAs) are strongly involved in BC initiation, metastatic progression, and drug resistance. In particular, aberrant expression of HOX transcript antisense intergenic RNA (HOTAIR) lncRNA plays an important role in BC contributing to its progression and represents a predictor of BC metastasis. For its proven prognostic value, HOTAIR could represent a potential therapeutic target in BC. In the present review, we summarize the role of HOTAIR in cancer progression and drug resistance, in particular in BC, and we illustrate the main approaches for silencing it.

Overexpression of MiR-146a-5p Upregulates lncRNA HOTAIR in Triple-Negative Breast Cancer Cells and Predicts Poor Prognosis

MiR-146a-5p plays different roles in different types of cancers. We showed that miR-146a-5p and long noncoding RNA HOTAIR were both upregulated in triple-negative breast cancer. Follow-up study showed that high levels of miR-146a-5p and HOTAIR in tumor tissues were closely correlated with poor survival. MiR-146a-5p and HOTAIR were positively correlated in tumor tissues. MiR-146a-5p positively regulated HOTAIR triple-negative breast cancer cells, while HOTAIR showed no regulatory effects on miR-146a-5p expression. MiR-146a-5p and HOTAIR positively regulated the migration and invasion of triple-negative breast cancer cells. In addition, HOTAIR silencing attenuated the effects of miR-146a-5p. Therefore, overexpression of miR-146a-5p may promote triple-negative breast cancer cell invasion and migration by upregulating HOTAIR.

Prognostic value of long non-coding RNA GHET1 in cancers: a systematic review and meta-analysis

Background

A number of studies have demonstrated the critical role of long non-coding RNA gastric cancer high expressed transcript 1 (GHET1) in many cancers. This meta-analysis provides an evidence-based evaluation of the prognostic role of GHET1 in cancer.

Materials and methods

Literature searches were conducted in several databases including Medline, Cochrane, EMBASE, CNKI, and Wanfang. The pooled odds ratio (OR) and hazard ratio (HR) with 95% confidence interval (CI) were used to evaluate the role of GHET1 in cancer. The study protocol was registered at PROSPERO (ID: CRD42018111252).

Results

Sixteen studies, containing 1315 patients, were analyzed in this meta-analysis. The pooled results indicated that GHET1 overexpression was significantly associated with poor overall survival (OS) and disease-free survival (DFS) in cancer. Moreover, up-regulation of GHET1 expression predicted larger tumor size, positive lymph node metastasis, positive distant metastasis, and advanced TNM (tumor-node-metastases) stage in human cancers.

Conclusion

There is a significant correlation between up-regulation of GHET1 and both poor prognosis and advanced clinicopathological cancer characteristics. GHET1 may be a potential prognostic predictor for human cancers.

Involvement of long noncoding RNAs in the pathogenesis of autoimmune diseases

Autoimmune diseases are a group of heterogeneous disorders characterized by damage to various organs caused by abnormal innate and adaptive immune responses. The pathogenesis of autoimmune diseases is extremely complicated and has not yet been fully elucidated. Long noncoding RNAs (lncRNAs), which are defined as transcripts containing more than 200 nucleotides with no protein-coding capacity, are emerging as important regulators of gene expression via epigenetic modification, transcriptional regulation and posttranscriptional regulation. Accumulating evidence has demonstrated that lncRNAs play a key role in the regulation of immunological functions and autoimmunity. In this review, we discuss various molecular mechanisms by which lncRNAs regulate gene expression and recent findings regarding the involvement of lncRNAs in many human autoimmune diseases, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), idiopathic inflammatory myopathy (IIM), systemic sclerosis (SSc) and Sjögren’s syndrome (pSS).

•

lncRNAs are observed to be differentially expressed in various autoimmune diseases.

•

lncRNAs are involved in abnormal immune regulation and inflammatory responses in autoimmune diseases, which provides new insight into disease pathogenesis.

•

LncRNAs may have the potential of biomarkers for diagnosis and prognosis of autoimmune diseases.

LncRNA-ZNF281 Interacts with miR-539 to Promote Hepatocellular Carcinoma Cell Invasion and Migration

Background: LncRNA-ZNF281 suppresses glioma, whereas its role in hepatocellular carcinoma (HCC) is unclear. This study aimed to investigate the interaction between ZNF281 and miR-539 in HCC. Materials and Methods: This study included 66 HCC patients (40 men and 26 women; 36-68 years, 53.1 ± 6.2 years) who were selected from the 133 HCC cases admitted to The First Affiliated Hospital of Fujian Medical University from February 2011 to June 2014. Levels of ZNF281 and miR-539 expression in two types of tissues (HCC and nontumor) were measured by performing quantitative polymerase chain reaction (qPCR). Dual-luciferase assay was performed to analyze the interactions between miR-539 and ZNF281 in both SNU-475 and PLHC-1 cells. The effects of ZNF281 and miR-539 overexpression on the invasion and migration of HCC cells were analyzed by performing transwell assays. Results: The authors showed that ZNF281 was upregulated and miR-539 was downregulated in HCC tissues and were negatively correlated. High levels of ZNF281 and low levels of miR-539 predicted the poor survival of HCC patients. Overexpression analysis showed that ZNF281 and miR-539 overexpression led to the downregulation of each other. Transwell assays showed that ZNF281 overexpression led to enhanced and miR-539 overexpression led to suppressed HCC cell invasion and migration. In addition, miR-539 overexpression attenuated the effects of ZNF281 overexpression. Conclusions: Therefore, ZNF281 may interact with miR-539 to promote HCC cell invasion and migration.

Prognostic Value of LncRNA HOTAIR in Colorectal Cancer: A Meta-analysis

HOX transcript antisense intergenic RNA (HOTAIR) is one of the most studied long noncoding RNAs (lncRNAs) and is aberrantly expressed in colorectal cancer (CRC). We thus performed a comprehensive study based on meta-analysis and validation of the TCGA database to investigate clinicopathological and prognostic value of HOTAIR in CRC. Six studies enrolling 629 CRC patients were included in the analysis. The results indicated that high HOTAIR expression predicted worse OS (hazard ratio [HR] = 2.46, 95% confidence interval [CI]: 1.82-3.32, P < 0.01) and RFS (HR = 1.97, 95% CI: 1.27-3.05, P < 0.01) for CRC patients. High HOTAIR expression was also significantly associated with venous invasion (OR = 2.53, 95% CI: 1.12-5.68, P = 0.02), advanced tumor infiltration (OR = 3.35, 95% CI: 1.34-8.42, P = 0.01) and distant metastasis (OR = 5.52, 95% CI: 1.22-25.01, P = 0.03). Then, the results were validated by the TCGA database, showing that the up-regulated expression of HOTAIR was significantly related to poor OS (P = 0.01) and RFS (P = 0.04) in CRC. Our meta-analysis indicated that high HOTAIR expression was closely associated with poor clinical outcomes and could be a reliable prognostic biomarker for CRC patients.

Chromatin-enriched RNAs mark active and repressive cis-regulation: An analysis of nuclear RNA-seq

Long noncoding RNAs (lncRNAs) localize in the cell nucleus and influence gene expression through a variety of molecular mechanisms. Chromatin-enriched RNAs (cheRNAs) are a unique class of lncRNAs that are tightly bound to chromatin and putatively function to locally cis-activate gene transcription. CheRNAs can be identified by biochemical fractionation of nuclear RNA followed by RNA sequencing, but until now, a rigorous analytic pipeline for nuclear RNA-seq has been lacking. In this study, we survey four computational strategies for nuclear RNA-seq data analysis and develop a new pipeline, Tuxedo-ch, which outperforms other approaches. Tuxedo-ch assembles a more complete transcriptome and identifies cheRNA with higher accuracy than other approaches. We used Tuxedo-ch to analyze benchmark datasets of K562 cells and further characterize the genomic features of intergenic cheRNA (icheRNA) and their similarity to enhancer RNAs (eRNAs). We quantify the transcriptional correlation of icheRNA and adjacent genes and show that icheRNA is more positively associated with neighboring gene expression than eRNA or cap analysis of gene expression (CAGE) signals. We also explore two novel genomic associations of cheRNA, which indicate that cheRNAs may function to promote or repress gene expression in a context-dependent manner. IcheRNA loci with significant levels of H3K9me3 modifications are associated with active enhancers, consistent with the hypothesis that enhancers are derived from ancient mobile elements. In contrast, antisense cheRNA (as-cheRNA) may play a role in local gene repression, possibly through local RNA:DNA:DNA triple-helix formation.

Nuclear RNA-seq provides a powerful way to profile the transcriptional landscape, especially the noncoding transcriptome. Through analyzing nuclear RNA-seq, the chromatin-enriched RNA (cheRNA) class of gene regulatory non-coding RNAs was identified. The computational framework presented here provides a reliable approach to identifying cheRNAs from nuclear RNA-seq, and for studying cell-type specific gene regulation. We find that intergenic cheRNA, including transcripts mapped to regions with high levels of classically repressive H3K9me3-marks, may act as a transcriptional activator. In contrast, antisense cheRNA, which originates from the DNA strand complementary to the candidate target protein-coding gene may interact with diverse chromatin modulators to repress local transcription. Our new pipeline allows the identification of a more complete set of cheRNAs than other approaches. A future challenge will be to refine the functional mechanisms of cheRNAs by exploring their regulatory roles, which are involved in diverse molecular and cellular processes in humans and other organisms.

Genistein Represses HOTAIR/Chromatin Remodeling Pathways to Suppress Kidney Cancer

BACKGROUND/AIMS

Genistein, a soy isoflavone, has been shown to have anti-cancer effects in various cancers including renal cancer. Long non-coding RNA, HOX transcript antisense RNA (HOTAIR), is involved in cancer progression and metastasis, such as renal cancer. Our aim was to investigate the effects of genistein on HOTAIR chromatin remodeling functions.

METHODS

We used MTS assays and Transwell migration assays to study the effects of genistein on cell proliferation and migration respectively in human renal cell carcinoma (RCC) cell lines. We used Western blots to analyze SNAIL and ZO-1 expression. We performed chromatin immunoprecipitation (ChIP) assays to study recruitment of the polycomb repressive complex 2 (PRC2) to the ZO-1 promoter. We performed RNA immunoprecipitation (RIP) assays to study interaction between HOTAIR and PRC2, SMARCB1 or ARID1A. We also performed transfection experiments to overexpress EED, HOTAIR and knockdown SMARCB1.

RESULTS

Genistein reduced cell proliferation and migration of human renal cell carcinoma cell lines. ChIP assays indicated that genistein reduces recruitment of the PRC2 to the ZO-1 promoter and increased its expression. RIP assays showed that genistein inhibits HOTAIR interaction with PRC2, leading to tumor suppression. Immunoprecipitation also revealed that genistein reduced EED levels in PRC2, suggesting that decreased EED levels suppress HOTAIR interaction with PRC2. EED overexpression in the presence of genistein restored PRC2 interaction with HOTAIR and reduced ZO-1 transcription, suggesting genistein activates ZO-1 by inhibiting HOTAIR/PRC2 functions. RIP assays also showed that HOTAIR interacts with SMARCB1 and ARID1A, subunits of the human SWI/SNF chromatin remodeling complex and genistein reduces this interaction. Combination of HOTAIR overexpression and SMARCB1 knockdown in the presence of genistein revealed that genistein inhibits SNAIL transcription via the HOTAIR/SMARCB1 pathway.

CONCLUSION

Genistein suppresses EED levels in PRC2 and inhibits HOTAIR/PRC2 interaction. Genistein suppresses HOTAIR/PRC2 recruitment to the ZO-1 promoter and enhances ZO-1 transcription. Genistein also inhibits SNAIL transcription via reducing HOTAIR/SMARCB1 interaction. We demonstrate that the reduction of HOTAIR interaction with chromatin remodeling factors by genistein represses HOTAIR/chromatin remodeling pathways to suppress RCC malignancy.

CARLo-5 as an oncogenic gene in endometrial carcinoma

The long noncoding RNA CARLo-5 is dysregulated in multiple types of human cancers. High CARLo-5 is a promising predictive factor for various cancers, including endometrial carcinoma (EC). Our previous study showed that the expression level of CARLo-5 was associated with advanced FIGO stage (The International Federation of Gynecology and Obstetrics), lymph node metastasis, and the poor survival of patients with EC. In the present study, we demonstrated that the downregulation of CARLo-5 could affect the proliferation, cell cycle, migration, and invasion of EC cell lines HEC-1B and KLE cells. The oncogenic activity of CARLo-5 was also confirmed with in vivo data. Mechanistically, CARLo-5 could affect the expression of CDK/CDKN1A and MMP2/9, which have been reported to be regulated by CARLo-5 and associated with cell cycle and motility. In conclusion, this study is the first to discover the biological function and mechanism of CARLo-5 in regulating the biological characteristics of EC cells. Targeting CARLo-5 and its pathway might provide new biomarkers or potential therapies target for patients with EC. Environ. Mol. Mutagen. 61:256-265, 2020. © 2019 Wiley Periodicals, Inc.

Effects of propofol on colon cancer metastasis through STAT3/HOTAIR axis by activating WIF-1 and suppressing Wnt pathway

BACKGROUND

In the present study, we aim to investigate the potential role of propofol in the tumor progression of colon cancer.

METHODS

Human colon cancer cell lines were cultured and exposed with 8 μg/mL propofol. RNA interference was performed to silence the expression of HOTAIR or STAT3 to explore their biological functions in colon cancer. Cell apoptosis and invasion were assessed using flow cytometry and transwell assays, respectively. Quantitative real-time PCR, western blot, and immunohistochemistry were subjected to measure the expression patterns of HOTAIR, STAT3, Wnt signaling factors, and epithelial-mesenchymal transition-related markers, respectively. Besides, nude mice were transplanted with colon cancer cells for further exploration. Tumor formation, volume, and weight were evaluated to validate the in vitro findings.

RESULTS

Propofol treatment promoted cell apoptosis and inhibited cell invasion in colon cancer cells, while the effects were reversed by HOTAIR overexpression. Additionally, STAT3 positively regulated HOTAIR expression, which was also negatively modulated by propofol. Moreover, STAT3 and HOTAIR were shown to independently regulate colon cancer cell apoptosis and invasion. Furthermore, HOTAIR could stimulate Wnt signaling pathway via inhibiting WIF-1 expression and upregulating β-catenin expression, which was also demonstrated by in vivo study.

CONCLUSION

Taken together, the current study demonstrated that propofol exerts the inhibition on cell invasion and promotion on cell apoptosis through regulating STAT3/HOTAIR by activating WIF-1 and suppressing Wnt pathway, indicating that propofol might serve as a therapeutic role for colon cancer patients in the future.

Long non-coding RNA-ZNF281 promotes cancer cell migration and invasion in gastric cancer via downregulation of microRNA-124

It has previously been determined that long non-coding (lnc)RNA-zinc finger protein (ZNF)281 serves an oncogenic role in breast cancer; however, the role of lncRNA-ZNF281 in other cancer types is yet to be elucidated. The present study aimed to analyze the role of ZNF281 in gastric cancer by characterizing its activity in cancerous tissues and normal tissues using RT-qPCR. Overexpression experiments were also performed to investigate the interaction between ZNF281 and miR-124, and Transwell assays were conducted to analyze cell invasion and migration. The present study revealed that lncRNA-ZNF281 was upregulated, and that microRNA (miR)-124 was downregulated, in cancerous tissues compared with that in the paired adjacent healthy tissues of patients with gastric cancer. In addition, the expression levels of lncRNA-ZNF281 and miR-124 exhibited a significant inverse association. Furthermore, in vitro cell experiments determined that lncRNA-ZNF281 overexpression resulted in miR-124 inhibition, yet miR-124 overexpression did not influence lncRNA-ZNF281 expression. lncRNA-ZNF281 expression level was also associated with the clinical stage of the patient. Bioinformatics analysis revealed that lncRNA-ZNF281 may target the base pairs in the hairpin loop of the miR-124 precursor. Subsequent in vitro cell experiments indicated that lncRNA-ZNF281 overexpression resulted in promoting the migration and invasiveness of gastric cancer cells, while miR-124 over-expression led to its inhibition. In addition, miR-124 overexpression partially recovered the effects of lncRNA-ZNF281 overexpression. Therefore, lncRNA-ZNF281 may promote cancer cell migration and invasion in gastric cancer via downregulation of miR-124.

A distal enhancer maintaining Hoxa1 expression orchestrates retinoic acid-induced early ESCs differentiation

Retinoic acid (RA) induces rapid differentiation of embryonic stem cells (ESCs), partly by activating expression of the transcription factor Hoxa1, which regulates downstream target genes that promote ESCs differentiation. However, mechanisms of RA-induced Hoxa1 expression and ESCs early differentiation remain largely unknown. Here, we identify a distal enhancer interacting with the Hoxa1 locus through a long-range chromatin loop. Enhancer deletion significantly inhibited expression of RA-induced Hoxa1 and endoderm master control genes such as Gata4 and Gata6. Transcriptome analysis revealed that RA-induced early ESCs differentiation was blocked in Hoxa1 enhancer knockout cells, suggesting a requirement for the enhancer. Restoration of Hoxa1 expression partly rescued expression levels of ∼40% of genes whose expression changed following enhancer deletion, and ∼18% of promoters of those rescued genes were directly bound by Hoxa1. Our data show that a distal enhancer maintains Hoxa1 expression through long-range chromatin loop and that Hoxa1 directly regulates downstream target genes expression and then orchestrates RA-induced early differentiation of ESCs. This discovery reveals mechanisms of a novel enhancer regulating RA-induced Hoxa genes expression and early ESCs differentiation.

Testicular expression of long non-coding RNAs is affected by curative GnRHa treatment of cryptorchidism

Background

Cryptorchidism is a frequent endocrinopathy in boys that has been associated with an increased risk of developing testicular cancer and infertility. The condition is curable by combined surgery and hormonal treatment during early pre-pubertal stages using gonadotropin releasing hormone agonist (GnRHa). However, whether the treatment also alters the expression of testicular long non-coding RNAs (lncRNAs) is unknown. To gain insight into the effect of GnRHa on testicular lncRNA levels, we re-analyzed an expression dataset generated from testicular biopsies obtained during orchidopexy for bilateral cryptorchidism.

Results

We identified EGFR-AS1, Linc-ROR, LINC00221, LINC00261, LINC00282, LINC00293, LINC00303, LINC00898, LINC00994, LINC01121, LINC01553, and MTOR-AS1 as potentially relevant for the stimulation of cell proliferation mediated by GnRHa based on their direct or indirect association with rapidly dividing cells in normal and pathological tissues. Surgery alone failed to alter the expression of these transcripts.

Conclusion

Given that lncRNAs can cooperate with chromatin-modifying enzymes to promote epigenetic regulation of genes, GnRHa treatment may act as a surrogate for mini-puberty by triggering the differentiation of Ad spermatogonia via lncRNA-mediated epigenetic effects. Our work provides additional molecular evidence that infertility and azoospermia in cryptorchidism, resulting from defective mini-puberty cannot be cured with successful orchidopexy alone.

lncRNA Metastasis-Associated Lung Adenocarcinoma Transcript 1 Promotes Proliferation and Invasion of Non-Small Cell Lung Cancer Cells via Down-Regulating miR-202 Expression

Objective

Accumulating evidences indicate that long non-coding RNAs (lncRNAs) play key roles in cancer. This study aims to clarify role of the metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in non-small cell lung cancer (NSCLC) and uncover the underlying mechanisms.

Materials and Methods

In this experimental study, MALAT1 and miR-202 expression in tissues and cell lines were detected using quantitative real time polymerase chain reaction (qRT-PCR) assay. Cell transfection was conducted using Lipofectamine 3000. Cell proliferation was determined with CCK-8 assay. MMP2 and MMP9 expressions were measured with Western blot. Cell invasive ability was evaluated by Transwell assay. Starbase 2.0 tool was used to predict targets of MALAT1. Dual luciferase reporter assay, RNA-binding protein immunoprecipitation assay and RNA pull-down assay were conducted to confirm the potential direct interaction between MALAT1 and miR-202.

Results

MALAT1 was overexpressed in NSCLC samples and cell lines. High expression of MALAT1 was related to large tumor size (>3 cm), poor histological grade, advanced cancer and tumor metastasis in NSCLC. In vitro assays exhibited that knockdown of MALAT1 remarkably decreased A549 cell growth and invasion capacity, while overexpression of MALAT1 significantly enhanced NCI-H292 cell proliferation and invasion ability. Next, we verified that MALAT1 could act as a competing endogenous RNA (ceRNA) by sponging miR-202 in NSCLC and there is a negative correlation between MALAT1 and miR-202. Besides, overexpression of miR-202 inhibited cell proliferation and invasive ability in MALAT1-overexpressed cells.

Conclusion

This study demonstrated that lncRNA-MALAT1 gets involved in NSCLC progression by targeting miR- 202, indicating that MALAT1 may serve as a novel therapeutic target for NSCLC treatment.

Upregulation of PUM1 Expression in Preeclampsia Impairs Trophoblast Invasion by Negatively Regulating the Expression of the lncRNA HOTAIR

Pumilio (PUM) proteins are members of a highly conserved RNA-binding protein family that posttranscriptionally regulate gene expression in many organisms. However, their roles in the placenta are unclear. In the present study, we report the requirement for the PUM homolog 1 (PUM1) gene in preeclampsia (PE). Immunofluorescence and immunohistochemical data showed that PUM1 was highly expressed in human placental villi from women with PE compared to healthy controls (HCs). Further, PUM1 overexpression repressed, and knockdown enhanced, the invasion and proliferation of trophoblasts. Interestingly, PUM1 knockdown promoted trophoblast invasion in a villous explant culture model, while PUM1 overexpression repressed these effects. Furthermore, lncRNA transcriptome sequencing coupled with RNA immunoprecipitation (RIP) revealed that PUM1 inhibits trophoblast invasion in PE by downregulating the expression of lncRNA HOTAIR. Moreover, PUM1 regulates HOTAIR expression via a posttranscriptional mechanism. Using RNA-protein pull-down and mRNA stability assays, we identified PUM1 as a specific binding partner that decreased the half-life of HOTAIR and lowered the steady-state level of HOTAIR expression, suggesting a novel posttranscriptional regulatory mechanism. Collectively, these findings identified a novel RNA regulatory mechanism, revealing a new pathway governing the regulation of PUM1/HOTAIR in trophoblast invasion in the pathogenesis of PE.

Prognostic and Clinicopathological Significance of Long Non-coding RNA PANDAR Expression in Cancer Patients: A Meta-Analysis

Background: Long non-coding RNA PANDAR is an emerging non-coding RNA mapping to 6p21.2. It underlies metastatic progression and chromosomal instability in a variety of cancers. Despite the fact that recent studies have revealed that lncRNA PANDAR may be a potential prognostic biomarker for patients with cancer, there has still been controversy on the prognostic value of PANDAR. Methods: Databases of PubMed, Embase, SinoMed, and Web of Science were carefully searched and the literature which investigated the prognostic value of PANDAR expression among human cancers was collected for further analysis. Odds ratios (ORs) or hazards ratios (HRs) with 95% confidence intervals (CIs) were pooled to estimate the relation between PANDAR expression and survival or clinicopathological characteristics of cancer patients. Results: There were 13 eligible studies in total, with 1,465 patients enlisted in this meta-analysis. All the eligible studies complied with the case-control study. The outcome showed that the elevated expression level of PANDAR was significantly related to poor overall survival (OS) (pooled HR 1.72, 95%CI 1.14-2.60). However, high or low expression of PANDAR did not differ in the prediction of event-free survival (EFS). Moreover, we discovered that high PANDAR expression was closely related to decreased OS in colorectal cancer (pooled HR 3.43, 95%CI 2.06-5.72) and reduced expression level of PANDAR was markedly related to poor OS (pooled HR 0.65, 95%CI 0.45-0.88) in non-small cell lung cancer. However, the expression level of PANDAR had no significant association with OS in renal cell carcinoma (pooled HR 1.19, 95%CI 0.56-2.50). Moreover, after analysis, we discovered that the high expression level of PANDAR was associated closely with the depth of invasion (pooled OR 3.95, 95%CI 2.36-6.63), lymph node metastasis (pooled OR 1.92, 95%CI 0.93-3.98), tumor stage (pooled OR 2.05, 95%CI 0.99-4.27), and distant metastasis (pooled OR 2.87, 95%CI 1.60-5.16). Conclusions: Our study revealed that increased PANDAR expression may serve as an adverse prognostic biomarker for cancer patients, thus helping the clinical decision-making process.

LncRNA SNHG4 promotes the proliferation, migration, invasiveness, and epithelial–mesenchymal transition of lung cancer cells by regulating miR-98-5p

Long noncoding RNA small nucleolar RNA host gene 4 (SNHG4) is usually up-regulated in cancer and regulates the malignant behavior of cancer cells. However, its role in lung cancer remains elusive. In this study, we silenced the expression of SNHG4 in NCI-H1437 and SK-MES-1, two representative non-small-cell lung cancer cell lines, by transfecting them with siRNA (small interfering RNA) that specifically targets SNHG4. We observed significantly inhibited cell proliferation in vitro and reduced tumor growth in vivo after SNHG4 silencing. SNHG4 knockdown also led to cell cycle arrest at the G1 phase, accompanied with down-regulation of cyclin-dependent kinases CDK4 and CDK6. The migration and invasiveness of these two cell lines were remarkably inhibited after SNHG4 silencing. Moreover, our study revealed that the epithelial–mesenchymal transition (EMT) of lung cancer cells was suppressed by SNHG4 silencing, as evidenced by up-regulated E-cadherin and down-regulated SALL4, Twist, and vimentin. In addition, we found that SNHG4 silencing induced up-regulation of miR-98-5p. MiR-98-5p inhibition abrogated the effect of SNHG4 silencing on proliferation and invasion of lung cancer cells. In conclusion, our findings demonstrate that SNHG4 is required by lung cancer cells to maintain malignant phenotype. SNHG4 probably exerts its pro-survival and pro-metastatic effects by sponging anti-tumor miR-98-5p.

Long noncoding RNA FOXD3-AS1 promotes colon adenocarcinoma progression and functions as a competing endogenous RNA to regulate SIRT1 by sponging miR-135a-5p

More and more documents have proved that the abnormal expression of long noncoding RNAs (lncRNAs) are correlated with the initiation and progression of colorectal cancer (CRC). lncRNA FOXD3-AS1 has been reported in glioma for its oncogenic property. According to the survival analysis of The Cancer Genome Atlas database, FOXD3-AS1 upregulation implied lower survival rate of patients with CRC. Quantitative real-time polymerase chain reaction showed the overexpression of FOXD3-AS1 in both CRC tissues and cells. The Kaplan-Meier method demonstrated the prognostic value of FOXD3-AS1 for patients with CRC. To explore the effect of FOXD3-AS1 on CRC progression, loss-of-function experiments were carried out, whose results indicated that knockdown of FOXD3-AS1 suppressed cell proliferation, migration, and invasion, inhibited cell cycle and promoted cell apoptosis in vitro. In vivo experiments affirmed that FOXD3-AS1 affected tumor growth. FOXD3-AS1 expression was enriched in the cytoplasm of CRC cells. Mechanism experiments revealed that FOXD3-AS1 served as a competing endogenous RNA to upregulate SIRT1 by sponging miR-135a-5p. In addition, SIRT1 silencing also restrained cell proliferation and motility. Rescue assays revealed the biological function of FOXD3-AS1/miR-135a-5p/SIRT1 axis in CRC progression. In conclusion, FOXD3-AS1 promotes CRC progression by regulating miR-135a-5p/SIRT1 axis, shedding lights on the way to CRC treatments.

Long Noncoding RNA (lncRNA)-Mediated Competing Endogenous RNA Networks Provide Novel Potential Biomarkers and Therapeutic Targets for Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer and has a high metastasis and reoccurrence rate. Long noncoding RNAs (lncRNAs) play an important role in CRC growth and metastasis. Recent studies revealed that lncRNAs participate in CRC progression by coordinating with microRNAs (miRNAs) and protein-coding mRNAs. LncRNAs function as competitive endogenous RNAs (ceRNAs) by competitively occupying the shared binding sequences of miRNAs, thus sequestering the miRNAs and changing the expression of their downstream target genes. Such ceRNA networks formed by lncRNA/miRNA/mRNA interactions have been found in a broad spectrum of biological processes in CRC, including liver metastasis, epithelial to mesenchymal transition (EMT), inflammation formation, and chemo-/radioresistance. In this review, we summarize typical paradigms of lncRNA-associated ceRNA networks, which are involved in the underlying molecular mechanisms of CRC initiation and progression. We comprehensively discuss the competitive crosstalk among RNA transcripts and the novel targets for CRC prognosis and therapy.

The rs12826786 in HOTAIR lncRNA Is Associated with Risk of Autism Spectrum Disorder

Autism spectrum disorder (ASD) encompasses a group of neurodevelopmental disorders with complex pattern of inheritance. Several single nucleotide polymorphisms (SNPs) within coding or non-coding regions of genome have been associated with risk of this disorder. In the current study, we genotyped rs12826786, rs1899663, and rs4759314 SNPs within HOX transcript antisense RNA (HOTAIR) in 427 ASD cases and 430 normally developed children. The rs12826786 was associated with ASD in allelic (T vs. C: OR (95% CI) = 1.29 (1.07-1.57), adjusted P value = 0.03) and recessive (TT vs. TC + CC: OR (95% CI) = 1.60 (1.10-2.32), adjusted P value = 0.04) models. However, the other SNPs were not associated with ASD in any inheritance model. No estimated haplotype within HOTAIR was associated with risk of ASD in the assessed population. Based on the results of the current investigation, the rs12826786 can be regarded as a risk locus for ASD in Iranian population.

Long Noncoding RNAs in Acute Myeloid Leukemia: Functional Characterization and Clinical Relevance

Acute Myeloid Leukemia (AML) is the most common form of leukemia in adults with an incidence of 4.3 per 100,000 cases per year. Historically, the identification of genetic alterations in AML focused on protein-coding genes to provide biomarkers and to understand the molecular complexity of AML. Despite these findings and because of the heterogeneity of this disease, questions as to the molecular mechanisms underlying AML development and progression remained unsolved. Recently, transcriptome-wide profiling approaches have uncovered a large family of long noncoding RNAs (lncRNAs). Larger than 200 nucleotides and with no apparent protein coding potential, lncRNAs could unveil a new set of players in AML development. Originally considered as dark matter, lncRNAs have critical roles to play in the different steps of gene expression and thus affect cellular homeostasis including proliferation, survival, differentiation, migration or genomic stability. Consequently, lncRNAs are found to be differentially expressed in tumors, notably in AML, and linked to the transformation of healthy cells into leukemic cells. In this review, we aim to summarize the knowledge concerning lncRNAs functions and implications in AML, with a particular emphasis on their prognostic and therapeutic potential.

Deregulated Expression of Long Non-coding RNA HOX Transcript Antisense RNA (HOTAIR) in Egyptian Patients with Multiple Myeloma

Increasing evidence of involvement of non-coding RNAs, especially long non-coding RNAs (lncRNAs), in the molecular biology of various malignancies have been recently reported. Their utilization as markers for diagnosis, prognosis and evaluation of treatment response was widely investigated. As the impact of lncRNA HOTAIR on multiple myeloma (MM) was not properly highlighted, we aimed to explore the expression levels of HOTAIR in three groups of MM patients and to analyze its relationship to different patients' characteristics. Plasma samples were withdrawn from 24 newly diagnosed MM patients, 23 post-therapy patients in complete response (CR) or very good partial response (VGPR) and 15 patients who had either progressive disease (PD) or relapse. The expression of lncRNA HOTAIR in MM patients and 20 healthy controls was analyzed by quantitative reverse transcription polymerase chain reactions. HOTAIR was significantly upregulated in newly diagnosed and PD/relapse categories in comparison with controls and MM patients who had achieved CR or VGPR (P < 0.001). Furthermore; HOTAIR expression levels correlated with the percentage of malignant plasma cells in bone marrow (P = 0.006) and disease stage (ISS stage) (P = 0.031). HOTAIR may be employed as  prognostic molecular marker and novel therapeutic tool for newly diagnosed MM patients.

Long non-coding RNA-HOTAIR promotes the progression of sepsis by acting as a sponge of miR-211 to induce IL-6R expression

Sepsis remains the primary cause of death in intensive care units and multiple long non-coding RNAs (lncRNAs) have been demonstrated to be dysregulated in samples of patients with sepsis. However, whether lncRNA-HOTAIR is involved in the etiology of sepsis remains unclear. The aim of the present study was to investigate the role of HOTAIR in sepsis and to reveal the associated mechanisms. A bioinformatics analysis and dual-luciferase reporter assay was performed to evaluate the interaction between HOTAIR and miR-211, as well as miR-211 and IL-6R. An animal model of sepsis was established in mice via cecal ligation and puncture. Interferon (IFN)-γ, interleukin (IL)-6, IL-17, tumor necrosis factor (TNF)-α, IL-1β, IL-6 receptor (R), microRNA (miR)-211 and HOTAIR expression was measured using reverse transcription-quantitative PCR. Cellular proliferation and apoptosis of monocytes were assessed using cell counting kit-8 assay and flow cytometry, respectively. miR-211 was revealed to be targeted by HOTAIR and IL-6R. The expression of IFN-γ, IL-6, IL-17, TNF-α, IL-1β, IL-6R and HOTAIR was significantly upregulated in the septic mice, whereas miR-211 expression was downregulated. The overexpression of hox transcript antisense RNA (HOTAIR) and knockdown of miR-211 were associated with an increased expression of IFN-γ, IL-6, IL-17, TNF-α, IL-1β and IL-6R in monocytes, while the overexpression of miR-211 exhibited the opposite effect. HOTAIR overexpression and miR-211 knockdown significantly inhibited cellular proliferation and promoted monocyte apoptosis, whereas the overexpression of miR-211 exhibited the opposite effects in monocytes. Therefore, HOTAIR may promote the progression of sepsis by indirectly regulating the expression of IL-6R via miR-211.

Upregulation of the long non-coding RNA FOXD2-AS1 is correlated with tumor progression and metastasis in papillary thyroid cancer

BACKGROUND

Mounting evidence has shown that long non-coding RNAs (lncRNAs) play critical regulation roles in the progression of various cancers. However, the biological role and clinical value of lncRNA FOXD2-AS1 in papillary thyroid cancer (PTC) remain to be elucidated.

METHODS

The expression of FOXD2-AS1 in PTC tissues and cell lines was evaluated by RT-qPCR and in situ hybridization. The association between FOXD2-AS1 expression levels and clinicopathologic features was analyzed through tissue microarray. The biological function of FOXD2-AS1 in PTC cells was determined both in vitro through CCK-8, EdU staining, colony formation and cell invasion assays and in vivo through a xenograft tumor model. Functional and pathway enrichment analysis were also conducted to analyze the molecular mechanism.

RESULTS

FOXD2-AS1 was significantly upregulated in PTC tissues, and high FOXD2-AS1 expression was positively associated with malignant potential factors in PTC patients. In addition, high level of FOXD2-AS1 expression was an unfavorable independent prognostic biomarker for patients with PTC. Moreover, we found that knockdown of FOXD2-AS1 could effectively inhibit PTC cell proliferation and invasion in vitro and suppress tumor growth of PTC in vivo. Bioinformatics analysis indicated that activation of cell cycle and apoptosis pathways might be involved in the oncogenic function of FOXD2-AS1 in PTC. Moreover, we demonstrated that FOXD2-AS1 directly interacted with miR-185-5p as miRNA sponge and overexpression of FOXD2-AS1 partially reversed the suppressive effect of miR-185-5p in TPC cells.

CONCLUSION

Our findings suggest FOXD2-AS1 functions as an oncogene and promotes the tumor progression and metastasis in PTC, which might serve as a promising prognostic biomarker and potential therapeutic target for PTC patients.

The novel long noncoding RNA LOC283070 is involved in the transition of LNCaP cells into androgen-independent cells via its interaction with PHB2

We sought to investigate the underlying mechanism of action of the long noncoding RNA (lncRNA) LOC283070 in the development of androgen independence in prostate cancer. The interactions between LOC283070 and target proteins were investigated by RNA pull-down and RNA-binding protein immunoprecipitation (RIP) assays. Subcellular fractionation and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) were used to detect the subcellular localization of LOC283070. Western blotting was performed to detect the expression of prohibitin 2 (PHB2). Luciferase activity assays were performed to evaluate the effects of LOC283070 and PHB2 on the androgen receptor (AR) signaling pathway. A methyl thiazolyl tetrazolium (MTT) assay and a growth curve assay were used to test cell viability. Flow cytometry was performed to analyze cell cycles. A transwell assay was employed to test cell migration. We identified PHB2 as an interaction partner of LOC283070 in the pull-down and RIP experiments. Furthermore, we confirmed that the enrichment of LOC283070 with PHB2 in androgen-independent LNCaP (LNCaP-AI) cells was much greater than that in LNCaP cells. Moreover, the expression of PHB2 was not significantly different between the two cell lines, and the expression of LOC283070 in the nuclei of the LNCaP-AI cells was significantly greater than that in the LNCaP cells. In vitro data revealed that PHB2 overexpression significantly inhibited AR activity and cell proliferation and migration and induced accumulation of prostate cancer cells in G0/G1 phase. Moreover, the overexpression of LOC283070 fully abrogated the effects of PHB2 overexpression. In conclusion, we found that LOC283070 can bind to PHB2 located in the nucleus and inhibit its effect, and this is one of the mechanisms by which LOC283070 is involved in the transition of LNCaP cells into androgen-independent cells.

Identification of Cancer-Related Long Non-Coding RNAs Using XGBoost With High Accuracy

In the past decade, hundreds of long noncoding RNAs (lncRNAs) have been identified as significant players in diverse types of cancer; however, the functions and mechanisms of most lncRNAs in cancer remain unclear. Several computational methods have been developed to detect associations between cancer and lncRNAs, yet those approaches have limitations in both sensitivity and specificity. With the goal of improving the prediction accuracy for associations of lncRNA with cancer, we upgraded our previously developed cancer-related lncRNA classifier, CRlncRC, to generate CRlncRC2. CRlncRC2 is an eXtreme Gradient Boosting (XGBoost) machine learning framework, including Synthetic Minority Over-sampling Technique (SMOTE)-based over-sampling, along with Laplacian Score-based feature selection. Ten-fold cross-validation showed that the AUC value of CRlncRC2 for identification of cancer-related lncRNAs is much higher than previously reported by CRlncRC and others. Compared with CRlncRC, the number of features used by CRlncRC2 dropped from 85 to 51. Finally, we identified 439 cancer-related lncRNA candidates using CRlncRC2. To evaluate the accuracy of the predictions, we first consulted the cancer-related long non-coding RNA database Lnc2Cancer v2.0 and relevant literature for supporting information, then conducted statistical analysis of somatic mutations, distance from cancer genes, and differential expression in tumor tissues, using various data sets. The results showed that our approach was highly reliable for identifying cancer-related lncRNA candidates. Notably, the highest ranked candidate, lncRNA AC074117.1, has not been reported previously; however, integrated multi-omics analyses demonstrate that it is the target of multiple cancer-related miRNAs and interacts with adjacent protein-coding genes, suggesting that it may act as a cancer-related competing endogenous RNA, which warrants further investigation. In conclusion, CRlncRC2 is an effective and accurate method for identification of cancer-related lncRNAs, and has potential to contribute to the functional annotation of lncRNAs and guide cancer therapy.

Long non-coding RNA TUG1 mediates 5-fluorouracil resistance by acting as a ceRNA of miR-197-3p in colorectal cancer

One major reason for the failure of advanced colorectal cancer (CRC) treatment is the occurrence of chemoresistance to fluoropyrimidine (Fu)-based chemotherapy. Accumulating evidence indicates that long non-coding RNAs (lncRNAs) play a critical role in cancerous processes as either oncogenes or tumor suppressor genes. Here, we observed lncRNA TUG1 was associated to the 5-Fu resistance in colorectal cancer. Firstly, quantitative analysis indicated that TUG1 was significantly increased in recurrence CRC patient samples. Kaplan-Meier survival analysis indicated that high TUG1 expression in CRC tissues was significantly associated with a higher rate of disease progression. TUG1 knockdown re-sensitized the 5-Fu resistance in colorectal cancer cells, which were 5-Fu-resistant colorectal cell line. Furthermore, bioinformatics analysis showed that miR-197-3p could directly bind to TUG1 suggesting TUG1 might work as a ceRNA to sponge miR-197-3p. Extensively, our study also showed that TYMS was the direct target of miR-197-3p in CRC cells. Taken together, our study suggests that TUG1 mediates 5-Fu resistance in CRC via miR-197-3p/TYMS axis.

Long non-coding RNA DRHC inhibits the proliferation of cancer cells in triple negative breast cancer by downregulating long non-coding RNA HOTAIR

Long non-coding RNA (lncRNA) downregulated in hepatocellular carcinoma (DRHC) is a tumor suppressor in liver cancer. However, the role of this lncRNA in breast cancer has not been investigated. The present study revealed that lncRNA DRHC was downregulated and lncRNA Hox transcript antisense RNA (HOTAIR) was upregulated in tumor tissues compared with adjacent healthy tissues in patients with triple negative breast cancer (TNBC). Expression levels of lncRNA DRHC and lncRNA HOTAIR were negatively correlated in tumor tissues but not in adjacent healthy tissues. The lncRNA DRHC expression level was correlated with tumor size but not tumor metastasis. In vitro overexpression of lncRNA DRHC in TNBC cell lines resulted in decreased expression of lncRNA HOTAIR; however, lncRNA HOTAIR overexpression did not affect the expression level of lncRNA DRHC. Overexpression of lncRNA DRHC inhibited, while overexpression of lncRNA HOTAIR promoted the proliferation of the TNBC cell lines. In addition, lncRNA HOTAIR overexpression attenuated the inhibitory effects of lncRNA DRHC overexpression on cancer cell proliferation. The results obtained in the current study suggested that lncRNA DRHC may inhibit the proliferation of TNBC cells by downregulating the expression of lncRNA HOTAIR.

The Regulatory Roles of Long Noncoding RNAs in Acute Myeloid Leukemia

In this post-genomic era, long noncoding RNAs (lncRNAs) are rapidly gaining recognition for their crucial roles across diverse biological processes and contexts. The human blood system is no exception, where dozens of lncRNAs have been established as regulators of normal and/or malignant hematopoiesis, and where ongoing works continue to uncover novel lncRNA functions. Our review focuses on lncRNAs that are involved in the pathogenesis of acute myeloid leukemia (AML) and the mechanisms through which they control gene expression in this disease context. We also comment on genome-wide sequencing or profiling studies that have implicated large sets of lncRNAs in AML pathophysiology.

LncRNA PTCSC3 inhibits cell proliferation in laryngeal squamous cell carcinoma by down-regulating lncRNA HOTAIR

It is known that lncRNA PTCSC3 inhibits thyroid cancer and glioma and STAT3 promotes cancer development. We, in the present study, investigated the potential involvement of PTCSC3 in laryngeal squamous cell carcinoma (LSCC) and explored its interactions with STAT3. In the present study, we showed that plasma PTCSC3 was down-regulated in early stage LSCC patients, and the down-regulation of PTCSC3 separated in early stage LSCC patients from control group. LncRNA HOTAIR was up-regulated in early stage LSCC patients and was significantly and inversely correlated with PTCSC3 in LSCC patients. PTCSC3 overexpression led to the inhibition of HOTAIR, while PTCSC3 expression was not significantly affected by HOTAIR overexpression. PTCSC3 overexpression mediated the inhibited, while HOTAIR overexpression mediated the promoted proliferation of LSCC cells. However, cell invasion and migration were not significantly affected by PTCSC3 overexpression. In addition, HOTAIR overexpression reduced the inhibitory effects of PTCSC3 overexpression on cancer cell proliferation. Moreover, PTCSC3 overexpression mediated the down-regulation of STAT3 and STAT3 overexpression mediated the up-regulation of HOTAIR. Therefore, PTCSC3 may negatively interact with HOTAIR through STAT3 to inhibit LSCC cell proliferation.

A Compound AC1Q3QWB Selectively Disrupts HOTAIR-Mediated Recruitment of PRC2 and Enhances Cancer Therapy of DZNep

Over 20% of cancer 'driver' genes encode chromatin regulators. Long noncoding RNAs (lincRNAs), which are dysregulated in various cancers, play a critical role in chromatin dynamics and gene regulation by interacting with key epigenetic regulators. It has been previously reported that the lincRNA HOTAIR mediates recruitment of polycomb repressive complex 2 (PRC2) leading to aberrant transcriptional silencing of tumor suppressor genes in glioma and breast cancer. Thus, lincRNA HOTAIR can serve as a promising therapeutic target. Herein, we identified a small-molecule compound AC1Q3QWB (AQB) as a selective and efficient disruptor of HOTAIR-EZH2 interaction, resulting in blocking of PRC2 recruitment and increasing tumor suppressors expression.

Methods: Molecular docking and high-throughput screening were performed to identify the small compound, AQB. RIP and ChIRP assays were carried to assess the selective interference of AQB with the HOTAIR-EZH2 interaction. The effects of AQB on tumor malignancy were evaluated in a variety of cancer cell lines and orthotopic breast cancer models. The combination therapy of AQB and 3-Deazaneplanocin A (DZNep), an inhibitor of the histone methyltransferase EZH2 was used in vitro and in orthotopic breast cancer and glioblastoma patient-derived xenograft (PDX) models.

Results: Tumor cells highly expressing HOTAIR and EZH2 were sensitive to AQB. APC2, as one of the target genes, was significantly up-regulated by AQB and led to degradation of β-catenin resulting in suppression of Wnt/β-catenin signaling which may contribute to inhibition of tumor growth and metastasis in vitro and in orthotopic breast cancer models. Remarkably, AQB enhanced the toxicity of DZNep in vitro. In orthotopic breast cancer and glioblastoma patient-derived xenografts (PDX) models, the combination of low doses of AQB and DZNep realized much better killing than DZNep treatment alone.

Conclusion: AQB is a HOTAIR-EZH2 inhibitor, which blocks PRC2 recruitment and has great potential as an effective agent for targeted cancer therapy.

LncRNA PACER is down-regulated in osteoarthritis and regulates chondrocyte apoptosis and lncRNA HOTAIR expression

LncRNA PACER is a chondrocyte inflammation-associated long non-coding RNA (lncRNA), and chondrocyte inflammation is involved in osteoarthritis (OA). We observed that plasma PACER was down-regulated, while plasma HOTAIR was up-regulated in OA patients. Altered plasma levels of PACER and HOTAIR distinguished OA patients from healthy controls. PACER and HOTAIR were inversely correlated in both OA patients and healthy controls. PACER overexpression mediated the down-regulation of HOTAIR, while HOTAIR overexpression did not significantly affect PACER. PACER overexpression led to inhibited, while HOTAIR overexpression led to promoted apoptosis of chondrocyte. HOTAIR overexpression attenuated the effects of PACER overexpression. Therefore, lncRNA PACER is down-regulated in OA and regulates chondrocyte apoptosis by down-regulating lncRNA HOTAIR.

HOTAIR as a Prognostic Predictor for Diverse Human Cancers: A Meta- and Bioinformatics Analysis

Several studies suggest that upregulated expression of the long non-coding RNA HOX transcript antisense RNA (HOTAIR) is a negative predictive biomarker for numerous cancers. Herein, we performed a meta-analysis to further investigate the prognostic value of HOTAIR expression in diverse human cancers. To this end, a systematic literature review was conducted in order to select scientific studies relevant to the association between HOTAIR expression and clinical outcomes, including overall survival (OS), recurrence-free survival (RFS)/disease-free survival (DFS), and progression-free survival (PFS)/metastasis-free survival (MFS) of cancer patients. Collectively, 53 eligible studies including a total of 4873 patients were enrolled in the current meta-analysis. Pooled hazard ratios (HRs) with their corresponding 95% confidence intervals (CIs) were calculated to assess the relationship between HOTAIR and cancer patients’ survival. Elevated HOTAIR expression was found to be significantly associated with OS, RFS/DFS and PFS/MFS in diverse types of cancers. These findings were also corroborated by the results of bioinformatics analysis on overall survival. Therefore, based on our findings, HOTAIR could serve as a potential biomarker for the prediction of cancer patient survival in many different types of human cancers.

Rosiglitazone Inhibits Activation of Hepatic Stellate Cells via Up-Regulating Micro-RNA-124-3p to Alleviate Hepatic Fibrosis

BACKGROUND

The activation of hepatic stellate cells (HSCs) is involved in hepatic fibrogenesis and is regulated by the decreased expression of peroxisome proliferator-activated receptor γ (PPARγ). Rosiglitazone (RGZ) is a highly potent agonist of PPARγ.

AIMS

To clarify molecular regulatory mechanism of RGZ in the activation of HSCs in hepatic fibrosis.

METHODS

A mouse model of hepatic fibrosis was established by carbon tetrachloride with or without RGZ intervention. A vector carrying pcDNA-HOTAIR was constructed and injected into a mouse model. HSCs were isolated from liver tissue and activated by transforming growth factor-β. The expression of miR-124-3p, HOTAIR, Col1A1, α-SMA, and PPARγ mRNAs was measured by quantitative real-time PCR. The level of PPARγ was measured by Western blotting. The interaction between HOTAIR and PPARγ was assessed by RNA immunoprecipitation (RIP) and RNA pull-down. The target gene of miR-124-3p was determined by luciferase reporter assay and RNA interference approaches.

RESULTS

The expression of Col1A1 and α-SMA was reduced after RGZ intervention. Different expressions of HOTAIR and miR-124-3p were observed in liver tissue and HSCs. The luciferase reporter assay and RNA interference approaches indicated that miR-124-3p negatively regulated HOTAIR expression. RIP and RNA pull-down results revealed that PPARγ was interacted by HOTAIR. The therapeutic effect of RGZ on hepatic fibrosis was reversed by overexpression of HOTAIR.

CONCLUSIONS

RGZ inhibits the activation of HSCs by up-regulating miR-124-3p. The silencing of HOTAIR by miR-124-3p in HSC activation provided the foundation to understand interactions of ncRNAs and potential treatment target in hepatic fibrosis.

Overexpression of ZEB2-AS1 lncRNA is associated with poor clinical outcomes in acute myeloid leukemia

Acute myeloid leukemia (AML) is a fatal hematopoietic malignancy with poor clinical outcomes. To determine whether the expression of the long non-coding (lnc)RNA zinc finger E-box binding homeobox 2 (ZEB2) antisense RNA 1 (ZEB2-AS1) is associated with clinical outcomes, its expression was analyzed in a retrospective cohort of 62 AML and 10 non-malignant cases. The results revealed that the expression of ZEB2-AS1 lncRNA was notably high and closely associated with adverse clinical outcomes in AML cases compared with the non-malignant cases, based on either modified Medical Research Council or European Leukemia Net risk stratification systems. Univariate analyses indicated that patients with a higher expression of ZEB2-AS1 lncRNA had significantly shorter overall survival (OS) (P=0.036) and disease-free survival (DFS) rates (P=0.039) compared with patients with a lower expression of ZEB2-AS1 lncRNA. In addition, patients with a higher expression of ZEB2-AS1 lncRNA had a significant lower complete remission rate in response to induction by chemotherapy compared with patients with a lower expression of ZEB2-AS1 lncRNA (P=0.031). In cases with low levels of ZEB2-AS1 lncRNA, patients treated with allogenic hematopoietic stem cell transplantation had significantly longer OS and DFS rates compared with that of chemotherapy-treated patients (P=0.037 and P=0.049 respectively). Furthermore, the knockdown of ZEB2-AS1 lncRNA effectively inhibited AML cell invasion and migration, which was closely associated with the downregulation of ZEB2 and upregulation of E-cadherin expression. Collectively, although its independent prognostic value for survival was not rigorously determined, ZEB2-AS1 lncRNA may function as a candidate marker to improve conventional risk stratification systems and the evaluation of therapeutic responses for AML.

Overexpression of serum exosomal HOTAIR is correlated with poor survival and poor response to chemotherapy in breast cancer patients

To investigate the source of serum exosomal HOTAIR, to uncover the diagnostic and prognostic values of serum exosomal HOTAIR, and to discern the expression of serum exosomal HOTAIR between neoadjuvant chemotherapy and response to tamoxifen therapy. Samples were collected from the Third Affiliated Hospital of Kunming Medical University, Tumor Hospital of Yunnan. Exosomes were isolated from serum, cell culture medium and tumor tissues. We used transmission electron microscopy and western immunoblotting assay to characterize exosomes, and real-time PCR (qPCR) to assess HOTAIR expression. Neoadjuvant chemotherapy and tamoxifen therapy were carried out according to established guidelines. Breast cancer patients expressed higher serum exosomal HOTAIR than did healthy individuals (P\0.001). Serum exosomal HOTAIR levels 3 months after surgery were markedly decreased compared with levels before surgery (P\0.001), and the expression level of exosomal HOTAIR in cell culture medium increased with time in both breast cancer cell lines (72 h greater than 48 h greater than 24 h, 48 h vs 24 h [ [P less than 0.05]; 72 h vs 24 h [P less than 0.01]. Expression of serum exosomal HOTAIR in nude mice was notably greater than in the mock control group (P less than 0.001). The results of the ROC analysis revealed an AUC for serum exosomal HOTAIR of 0.9178 with a 95% CI of 0.8407-1.017 (P less than 0.01). The AUC for the CA15-3 cell line was 0.7378 (95% CI, 0.5585-0.9170; P = 0.03). High expression of exosomal HOTAIR led to a worse disease-free survival (P = 0.0481) and overall survival (P = 0.0463). In the high-expression chemotherapy group, six patients achieved a partial response (PR) and eight demonstrated stable disease (SD) and nine patients achieved PR and two SD in the low-expression group (P = 0.048). In the low-expression tamoxifen group, one patient had a recurrence of breast cancer and another 10 patients exhibited no recurrence, while six showed recurrence, and seven had none in the highexpression group (P = 0.035). We isolated exosomes successfully, and demonstrated that serum exosomal HOTAIR originated from primary breast cancer tissue. We conclude that serum exosomal HOTAIR exhibits the potential to be a diagnostic and prognostic biomarker. High expression of serum exosomal HOTAIR was also correlated with poor neoadjuvant chemotherapy and response to tamoxifen therapy.

Host relieves lnc-IRAK3-3-sequestered miR-891b to attenuate apoptosis in Enterovirus 71 infection

Enterovirus 71 (EV71) is an emerging life-threatening pathogen particularly in the Asia-Pacific region. Apoptosis is a major pathogenic feature in EV71 infection. However, which molecular mechanism participating in EV71-induced apoptosis is not completely understood. Long noncoding RNAs (lncRNAs), a newly discovered class of regulatory RNA molecules, govern a wide range of biological functions through multiple regulatory mechanisms. Whether lncRNAs involved in EV71-induced apoptosis was investigated in this study. We conducted an apoptosis-oriented approach by integrating lncRNA and mRNA profilings. lnc-IRAK3-3 is down-regulated in EV71 infection and plays an important role in EV71 infection-induced apoptosis. Compensation of lnc-IRAK3-3 in EV71 infection promoted cell apoptosis wherein GADD45β expression was increased and further triggered caspase3 and PARP cleavage. Using bioinformatics analysis and functional assays, lnc-IRAK3-3 could functionally sequester miR-891b and GADD45β 3'UTR whereas miR-891b showed the inhibitory activity on GADD45β expression. Taken together, lnc-IRAK3-3 has the ability capturing miR-891b to enforce GADD45β expression and eventually promotes apoptosis. On the contrary, host cells suppress lnc-IRAK3-3 to relieve lnc-IRAK3-3-sequestered miR-891b, restrain GADD45β, and attenuate apoptosis in EV71 infection that prevent host cells from severe damages. We discover a new molecular mechanism by which host cells counteract EV71-induced apoptosis through the lnc-IRAK3-3/miR-891b/GADD45β axis partially.

Long non-coding RNAs in Oral squamous cell carcinoma: biologic function, mechanisms and clinical implications

There is growing evidence that regions of the genome that cannot encode proteins play an important role in diseases. These regions are usually transcribed into long non-coding RNAs (lncRNAs). LncRNAs, little or no coding potential, are defined as capped transcripts longer than 200 nucleotides. New sequencing technologies have shown that a large number of aberrantly expressed lncRNAs are associated with multiple cancer types and indicated they have emerged as an important class of pervasive genes during the development and progression of cancer. However, the underlying mechanism in cancer is still unknown. Therefore, it is necessary to elucidate the lncRNA function. Notably, many lncRNAs dysregulation are associated with Oral squamous cell carcinoma (OSCC) and affect various aspects of cellular homeostasis, including proliferation, survival, migration or genomic stability. This review expounds the up- or down-regulation of lncRNAs in OSCC and the molecular mechanisms by which lncRNAs perform their function in the malignant cell. Finally, the potential of lncRNAs as non-invasive biomarkers for OSCC diagnosis are also described. LncRNAs hold promise as prospective novel therapeutic targets, but more research is needed to gain a better understanding of their biologic function.

Association of HOTAIR gene polymorphisms and haplotypes with uterine leiomyoma susceptibility in southeast of Iran

Uterine leiomyoma (UL) is the most common benign tumor of the uterus. HOX transcript antisense RNA (HOTAIR) as a lncRNAs is the product of HOXC gene that plays a major role in the invasion and development of different tumors. Several lines of evidence have been suggested the effects of HOTAIR polymorphisms on cancer risk. The aim of the present study was to analyze the effects of HOTAIR polymorphisms (rs12826786, rs920778, rs4759314 and rs1899663) on UL in southeast of Iran. A total of 152 women with UL and 182 age-matched healthy women were selected in the case-control study. The PCR-RFLP and ARMS-PCR methods were used for genotyping. HOTAIR rs920778 polymorphism was associated with a lower risk of UL in dominant [OR, 0.5 (95% CI, 0.3-0.9); P = 0.03], recessive [OR, 0.6 (95% CI, 0.4-0.9; P = 0.016] and allelic models [OR, 0.6(95% CI, 0.5-0.9); P = 0.004]. However, HOTAIR rs12826786 polymorphism was associated with a higher risk of UL in dominant [OR, 2.6 (95% CI, 1.6-4.1); P = 0.0001], recessive [OR, 1.9 (95% CI, 1-3.6); P = 0.04] and allelic models [OR, 1.8 (95% CI, 1.3-2.4); P = 0.0003]. There was no association between HOTAIR rs4759314 and rs1899663 polymorphisms and UL susceptibility. The frequency of CTGA haplotype was lower in UL women; however, the CCGA, TCGA, TTTA, and TTGA haplotypes were more frequent in UL women. Our results indicated that HOTAIR rs12826786 and rs920778 polymorphisms had a significant effect on UL susceptibility. The HOTAIR haplotypes could affect UL susceptibility.

Interplay between long non-coding RNAs and epigenetic machinery: emerging targets in cancer?

Of the diverse array of putative molecular and biological functions assigned to long non-coding RNAs (lncRNAs), one attractive perspective in epigenetic research has been the hypothesis that lncRNAs directly interact with the proteins involved in the modulation of chromatin conformation. Indeed, epigenetic modifiers are among the most frequent protein partners of lncRNAs that have been identified to date, of which histone methyltransferases and protein members of the Polycomb Repressive Complex PRC2 have received considerable attention. This review is focused on how lncRNAs interface with epigenetic factors to shape the outcomes of crucial biological processes such as regulation of gene transcription, modulation of nuclear architecture, X inactivation in females and pre-mRNA splicing. Because of our increasing knowledge of their role in development and cellular differentiation, more research is beginning to be done into the deregulation of lncRNAs in human disorders. Focusing on cancer, we describe some key examples of disease-focused lncRNA studies. This knowledge has significantly contributed to our ever-improving understanding of how lncRNAs interact with epigenetic factors of human disease, and has also provided a plethora of much-needed novel prognostic biomarker candidates or potential therapeutic targets. Finally, current limitations and perspectives on lncRNA research are discussed here.This article is part of a discussion meeting issue 'Frontiers in epigenetic chemical biology'.

LncRNA BLACAT1 May Serve as a Prognostic Predictor in Cancer: Evidence from a Meta-Analysis

Background

As a newly discovered lncRNA, bladder cancer-associated transcript 1 (BLACAT1) has been reported to correlate with poor clinical outcomes in several different cancers. This study aimed to evaluate its generalized predictive value for cancer prognosis.

Materials and Methods

We thoroughly searched PubMed, Embase, and Web of Science databases for eligible studies published until November 11, 2018, in which the relationship between BLACAT1 expression and cancer prognosis was explored. The analyses were performed using Review Manager Version 5.3 and Stata SE 12.0. The primary endpoints included overall survival (OS), pathological characteristics (TNM stage and tumor grade), lymph node metastasis (LNM), and distant metastasis.

Results

Ten studies containing 861 patients with 7 different cancerous diseases were eventually included. The results demonstrated that patients with high lncRNA BLACAT1 expression had a significantly shorter OS (HR: 1.82, 95% CI: 1.44-2.30, p < 0.00001) than patients with low lncRNA BLACAT1 expression. Moreover, elevated BLACAT1 expression was significantly associated with advanced TNM stage (OR: 2.29, 95% CI: 1.15-4.56, p = 0.005), high tumor grade (OR: 1.67, 95% CI: 1.11-2.53, p = 0.01), and lymph node metastasis (OR: 2.53, 95% CI: 1.80-3.57, p < 0.00001). Meanwhile, the expression of BLACAT1 had no significant association with age (p = 0.92), gender (p = 0.55), and smoking (p = 0.62).

Conclusion

High expression of lncRNA BLACAT1 may predict a poor prognosis in OS, TNM stage, tumor grade, and LNM. Its predictive roles were not significantly affected by age, gender, or smoking. Therefore, lncRNA BLACAT1 may serve as a promising predictor in cancer prognosis.