Role of lncRNAs as Novel Biomarkers and Therapeutic Targets in Ovarian Cancer

LncRNA SLC25A21-AS1 increases the chemosensitivity and inhibits the progression of ovarian cancer by upregulating the expression of KCNK4

Owing to high mortality rate, ovarian cancer seriously threatens women's health. Extensive abdominal metastasis and chemoresistance are the leading causes of ovarian cancer deaths. Through lncRNA sequencing, our previous study identified lncRNA SLC25A21-AS1, which was significantly downregulated in chemoresistant ovarian cancer cells. In this study, we aimed to evaluate the role and mechanism of SLC25A21-AS1 in ovarian cancer. The expression of SLC25A21-AS1 was analyzed by qRT-PCR and online database GEPIA. The biological functions of SLC25A21-AS1 and KCNK4 were analyzed by CCK-8, transwell, and flow cytometry. The specific mechanism was analyzed by RNA-sequencing, RNA binding protein immunoprecipitation, rescue experiments, and bioinformatic analysis. SLC25A21-AS1 was decreased in ovarian cancer tissues and cell lines. Overexpression of SLC25A21-AS1 enhanced the sensitivity of ovarian cancer cells to paclitaxel and cisplatin, and inhibited cell proliferation, invasion, and migration, while SLC25A21-AS1-silencing showed the opposite effect. Potassium channel subfamily K member 4 (KCNK4) was significantly up-regulated upon enforced expression of SLC25A21-AS1. Overexpression of KCNK4 inhibited cell proliferation, invasion, migration ability, and enhanced the sensitivity of ovarian cancer cells to paclitaxel and cisplatin. Meanwhile, KNCK4-overexpression rescued the promotive effect of SLC25A21-AS1-silencing on cell proliferation, invasion and migration. In addition, SLC25A21-AS1 could interact with the transcription factor Enhancer of Zeste Homolog 2 (EZH2), while EZH2 knockdown increased the expression of KCNK4 in some of the ovarian cancer cell lines. SLC25A21-AS1 enhanced the chemosensitivity and inhibited the proliferation, migration, and invasion ability of ovarian cancer cells at least partially by blocking EZH2-mediated silencing of KCNK4.

Long noncoding RNA SNHG6 silencing sensitized esophageal cancer cells to 5-FU via EZH2/STAT pathway

Chemotherapy was the main treatment method for esophageal cancer (EC) patients. However, chemotherapy resistance due to multiple factors is a major barrier to EC treatment. For investigating how small nucleolar RNA host gene 6 (SNHG6) affected the 5-fluorouracil (5-FU) resistance in EC as well as its possible molecular mechanism. This work conducted cell viability assay, clone formation, scratch assays together with cell apoptosis for evaluating the roles of SNHG6 and enhancer of zeste homolog 2 (EZH2, the histone-lysine N-methyltransferase). Relevant molecular mechanism was identified by RT-qPCR analysis together with Western-blot (WB) assays. Our data showed that SNHG6 expression increased in EC cells. SNHG6 promotes colony formation and migration, whereas suppresses EC cell apoptosis. SNHG6 silencing markedly promoted 5-FU-mediated suppression on KYSE150 and KYSE450 cells. Additional mechanism studies showed that SNHG6 modulating STAT3 and H3K27me3 via promoting EZH2 level. Similar to the function of SNHG6, abnormal expression of EZH2 promotes the malignancy of EC and intensifies its resistance to 5-FU. In addition, overexpression of EZH2 abolished the role of SNHG6 silencing in 5-FU sensitivity in EC cells. SNHG6 overexpression promoted malignancy of EC and increased EC cell resistance to 5-FU. Besides, further molecular mechanism studies provided a novel regulatory pathways that SNHG6 knockdown promoted EC cell sensitivity to 5-FU by modulating STAT3 and H3K27me3 via promoting EZH2 expression.

Effects of Autophagy-Related Genes on the Prognosis and Immune Microenvironment of Ovarian Cancer

Ovarian cancer (OC) is among the most malignant tumors of the female reproductive system. The role of autophagy in cancer is complex, and the functional relationship between autophagy-related genes and OC remains unclear. Here, the prognostic value of autophagy-related genes in OC and relationships between autophagy and immune function were evaluated. OC data from The Cancer Genome Atlas and the Human Autophagy Database were obtained to identify autophagy-related genes. Univariate and multivariate Cox analyses were used to construct a prognostic model based on autophagy-related genes. Relationships between risk scores and clinical traits were evaluated. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Cytoscape were used to analyze gene functions and their effects on the immune microenvironment. Relationships between autophagy genes and long noncoding RNAs (lncRNAs) were evaluated by Pearson's correlation coefficients, and lncRNAs corresponding to the autophagy-related genes associated with OC prognosis were used to construct a model. Relationships between risk scores and survival and prognosis were evaluated. Finally, a gene set enrichment analysis was performed. Seven autophagy-related genes (CAPN1, CDKN1B, DNAJB1, GNAI3, MTMR14, RHEB, and SIRT2) were identified as independent predictors of prognosis. Three lncRNAs corresponding to autophagy genes independently influenced prognosis. Autophagy genes are closely related to immunity. Fifteen immune cell types showed different levels of infiltration between the high- and low-risk groups. Moreover, immune cell infiltration differed between the high- and low-risk groups based on the model. Our analysis of genes and lncRNAs related to prognosis clarifies the role of autophagy in OC and provides a theoretical basis for further research.

LncRNACASC9 promotes proliferation, metastasis, and cell cycle inovarian carcinoma cells through cyclinG1/TP53/MMP7 signaling

Ovarian cancer (OC) brings about serious physical and psychological burden for female patients. LncRNA CASC9 has been reported to be intimately linked with the occurrence and development of several tumors. However, the biological role of lncRNA CASC9 in OC still lacks sufficient evidence. The expressions of CASC9 and miR-488-3p in OC cell lines and xenograft mice were detected by qRT-PCR assay. Cell Counting Kit-8 (CCK-8) assay was used to assess cell inhibition rate and cell proliferation in OVCAR-3 and OVCAR-3/DDP cells. Wound healing assay and transwell assay were performed to evaluate the capacity of migration and invasion, respectively. In addition, cell apoptosis was measured by TUNEL assay and cell cycle was assessed by flow cytometric analysis. Moreover, western blotting was carried out to detect the cyclinG1 (CCNG1)/TP53/MMP7 signaling and apoptosis-related proteins. Furthermore, luciferase reporter assay was performed to verify the combination of CASC9 with CCNG1 and miR-488-3p. The results of our study revealed that CASC9 expression was upregulated while miR-488-3p and CCNG1 expression was downregulated in OC cells with significant higher TP53 and MMP7 protein levels compared with normal ovarian surface epithelial cells. Additionally, luciferase reporter assay confirmed CASC9 bond to miR-488-3p/CCNG1. CASC9 silencing inhibited cell proliferation, migration, and invasion whereas promoted cell inhibition rate and apoptosis in vitro and in vivo. However, CASC9 overexpression showed the opposite effects. In summary, LncRNA CASC9 played a regulative role in ovarian carcinoma by cyclinG1/TP53/MMP7 signaling via binding to miR-488-3p in vivo and in vitro.

Long noncoding RNA LINC00858 promotes the progression of ovarian cancer via regulating the miR-134-5p/TRIM44 axis

Recent studies have shown that many long noncoding RNAs (lncRNAs) are abnormally expressed in ovarian cancer and involved in the pathological progress of ovarian cancer. In the present study, we aimed to investigate the role of lncRNA LINC00858 and the potential mechanism in ovarian cancer. The qRT-PCR was used to measure the expression levels of LINC00858 and miR-134-5p in ovarian cancer tissue specimens and cell lines. Loss-of-function assays were performed to investigate the role of LINC00858 in ovarian cancer. MTT assay was carried out to measure cell proliferation. Transwell assays were performed to determine cell migration and invasion. Biological information analysis and luciferase report gene assay were used to verify potential downstream genes of LINC00858. The xenograft mouse model was established to analyze tumor growth in vivo. Our results showed that LINC00858 was highly expressed in human ovarian cancer tissues and cell lines. Knockdown of LINC00858 inhibited cell proliferation, migration and invasion of SKOV3 cells, and suppressed tumor growth in mouse xenograft models. Mechanistic studies revealed that LINC00858 acted as a sponge of miR-134-5p and then regulated TRIM44 expression in SKOV3 cells. Furthermore, rescue experiments illustrated that inhibition of miR-134-5p restored the inhibitory effects of LINC00858 knockdown on cell proliferation, migration and invasion. TRIM44 overexpression could counteract the inhibitory effects of miR-134-5p mimics on ovarian cancer cells. In conclusion, these findings demonstrated that LINC00858 exerted oncogenic role in ovarian cancer, which was mediated by miR-134-5p/TRIM44 axis. Thus, LINC00858 might be a therapeutic target for the treatment of ovarian cancer.

Long non-coding RNA FAM83H-AS1 acts as a potential oncogenic driver in human ovarian cancer

OBJECTIVE

Ovarian cancer (OC) is one of the most aggressive women cancers with increasing incidence and mortality rates worldwide. Long non-coding RNAs (lncRNAs) could as major players in OC process. Although FAM83H antisense RNA1 (FAM83H-AS1) is demonstrated play an important roles in a many cancers, the detailed function and mechanism has not been reported in OC.

RESULTS

We integrated multiple kinds of bioinformatics approaches and experiments validated method to evaluate functions of FAM83H-AS1 in OC. Some differential expressed lncRNAs were identified between OC and normal control tissues. FAM83H-AS1 was one of most differentially expressed lncRNAs and up-regulated in multiple cancer types. Specially, expression of FAM83H-AS1 was higher in OC and showed difference in diverse stages. High FAM83H-AS1 expression is associated with worse pan-cancer and OC outcomes. FAM83H-AS1-centric network including lncRNA-miRNA, lncRNA-protein and lncRNA-mRNA ceRNA network were constructed to infer the function and mechanism of FAM83H-AS1. There were two methylation sites including cg01399317 and cg20519035 located at FAM83H-AS1. The methylation level of cg01399317 was correlated with gene expression of FAM83H-AS1. The expression level of FAM83H-AS1 was correlated with infiltration level of immune cell including macrophage, neutrphil and dendritic cell in OC patients. Lastly, qRT-PCR showed that the expression of FAM83H-AS1 was higher in OC tissues than normal control tissues.

CONCLUSION

Collectively, these results indicated that FAM83H-AS1 may act as an oncogenic driver and it may be a potential therapy target in OC.

Long non-coding RNA SNHG9 inhibits ovarian cancer progression by sponging microRNA-214-5p

Ovarian cancer ranks 7th among the most common cancer types affecting women worldwide. A number of studies have confirmed that multiple long non-coding RNAs participate in the occurrence and progression of ovarian cancer. Small nucleolar RNA host gene 9 (SNHG9) serves a role in the progression of glioblastoma and pancreatic cancer. However, the specific biological function of SNHG9 in ovarian cancer has not yet been fully investigated. The present study aimed to determine the biological role and potential molecular mechanism underlying the influence of SNHG9 in ovarian cancer. SNHG9 expression in ovarian cancer cell lines and tissues were measured via reverse transcription-quantitative PCR analysis, and cell proliferation was detected via Cell Counting Kit-8 and colony formation assays. Flow cytometry was performed to assess cell cycle progression, and Transwell and wound healing assays were performed to assess cell invasion and migration abilities. Bioinformatics software was utilized to determine the target genes of SNHG9, which were subsequently verified via dual-luciferase reporter and RNA immunoprecipitation assays. The results demonstrated that SNHG9 expression was remarkably lower in ovarian cancer cell lines and tissues compared with the negative controls. Cell function assays demonstrated that decreased SNHG9 expression notably induced the migration, colony formation, proliferation and invasiveness of ovarian cancer cells. Furthermore, the inhibitory effect of SNHG9 on the migration, colony formation, proliferation and invasion of ovarian cancer cells was partially reversed by miR-214-5p upregulation. Thus, taken together, the current results suggest that SNHG9 may serve as a tumor suppressor gene in ovarian cancer by regulating the miR-214-5p/cryptochrome circadian regulator 2 axis.

LncRNAs in Ovarian Cancer Progression, Metastasis, and Main Pathways: ceRNA and Alternative Mechanisms

Ovarian cancer (OvCa) develops asymptomatically until it reaches the advanced stages with metastasis, chemoresistance, and poor prognosis. Our review focuses on the analysis of regulatory long non-coding RNAs (lncRNAs) competing with protein-coding mRNAs for binding to miRNAs according to the model of competitive endogenous RNA (ceRNA) in OvCa. Analysis of publications showed that most lncRNAs acting as ceRNAs participate in OvCa progression: migration, invasion, epithelial-mesenchymal transition (EMT), and metastasis. More than 30 lncRNAs turned out to be predictors of survival and/or response to therapy in patients with OvCa. For a number of oncogenic (CCAT1, HOTAIR, NEAT1, and TUG1 among others) and some suppressive lncRNAs, several lncRNA/miRNA/mRNA axes were identified, which revealed various functions for each of them. Our review also considers examples of alternative mechanisms of actions for lncRNAs besides being ceRNAs, including binding directly to mRNA or protein, and some of them (DANCR, GAS5, MALAT1, and UCA1 among others) act by both mechanisms depending on the target protein. A systematic analysis based on the data from literature and Panther or KEGG (Kyoto Encyclopedia of Genes and Genomes) databases showed that a significant part of lncRNAs affects the key pathways involved in OvCa metastasis, EMT, and chemoresistance.

The Interplay between Long Noncoding RNAs and Proteins of the Epigenetic Machinery in Ovarian Cancer

Comprehensive large-scale sequencing and bioinformatics analyses have uncovered a myriad of cancer-associated long noncoding RNAs (lncRNAs). Aberrant expression of lncRNAs is associated with epigenetic reprogramming during tumor development and progression, mainly due to their ability to interact with DNA, RNA, or proteins to regulate gene expression. LncRNAs participate in the control of gene expression patterns during development and cell differentiation and can be cell and cancer type specific. In this review, we described the potential of lncRNAs for clinical applications in ovarian cancer (OC). OC is a complex and heterogeneous disease characterized by relapse, chemoresistance, and high mortality rates. Despite advances in diagnosis and treatment, no significant improvements in long-term survival were observed in OC patients. A set of lncRNAs was associated with survival and response to therapy in this malignancy. We manually curated databases and used bioinformatics tools to identify lncRNAs implicated in the epigenetic regulation, along with examples of direct interactions between the lncRNAs and proteins of the epigenetic machinery in OC. The resources and mechanisms presented herein can improve the understanding of OC biology and provide the basis for further investigations regarding the selection of novel biomarkers and therapeutic targets.

Differentially expressed lncRNAs, miRNAs and mRNAs with associated ceRNA networks in a mouse model of myocardial ischemia/reperfusion injury

Non‑coding RNAs, including long non‑coding RNAs (lncRNAs) and microRNAs (miRNAs/miRs), have significant regulatory effects on a number of biological processes in myocardial ischemia/reperfusion (I/R) injury, including cell differentiation, proliferation and apoptosis. In the present study, the expression levels of lncRNAs, miRNAs and mRNAs were evaluated in a mouse model of myocardial I/R injury. The potential functions of these differentially expressed genes were then analyzed via Gene Ontology and pathway analyses. Additionally, the interactions between lncRNA‑miRNA‑mRNA were predicted by constructing a competing endogenous RNA regulatory network. It was found that 14,366 lncRNAs, 151 miRNAs and 9,377 mRNAs were differentially expressed in mice hearts after I/R compared with the Sham group (fold change >2; P<0.05). The results indicated that these differentially expressed genes were involved in multiple molecular functions, including 'guanosine diphosphate binding', 'RNA polymerase II carboxy‑terminal domain kinase activity', 'TATA‑binding protein‑class protein binding', 'nicotinamide adenine dinucleotide binding' and 'protein phosphatase type 2A regulator activity'. The interactions between lncRNA‑miRNA‑mRNA, including five lncRNAs, 38 miRNAs and 196 mRNAs, were predicted, specifically Gm12040‑mmu‑miR‑125a‑5p‑decapping mRNA 1B, Rpl7l1‑ps1‑mmu‑miR‑124‑3p‑G protein‑coupled receptor 146, Gm11407‑mmu‑miR‑190a‑5p‑homeobox and leucine zipper encoding (HOMEZ), 1600029O15Rik‑mmu‑miR‑132‑3p‑HOMEZ and AK155692‑mmu‑miR‑1224‑3p‑activating transcription factor 6β. Collectively, these findings provided novel insights for future research on lncRNAs, miRNAs and mRNAs in myocardial I/R injury.

The long non-coding RNA PTTG3P promotes growth and metastasis of cervical cancer through PTTG1

The outgrowth and metastasis of cervical cancer (CC) contribute to its malignancy. Pituitary Tumor Transforming Gene 1 (PTTG1) is upregulated in many types of cancer, and enhances tumor cell growth and metastasis. However, the activation and regulation of PTTG1 in CC, especially by its pseudogene PTTG3P, have not been shown. Here, we detected significantly higher levels of PTTG1 and PTTG3P in the resected CC tissue, compared to the paired adjacent normal cervical tissue. Interestingly, the PTTG3P levels positively correlated with the PTTG1 levels. High PTTG3P levels were associated with poor patients’ survival. In vitro, PTTG1 were increased by PTTG3P overexpression, but was inhibited by PTTG3P depletion in CC cells. However, PTTG3P levels were not altered by modulation of PTTG1 in CC cells, suggesting that PTTG3P is upstream of PTTG1. Moreover, PTTG3P increased CC cell growth, likely through CCNB1-mediated increase in cell proliferation, rather than through decrease in cell apoptosis. Furthermore, PTTG3P increased CC cell invasiveness, likely through upregulation of SNAIL and downregulation of E-cadherin. Our work thus suggests that PTTG3P may promote growth and metastasis of CC through PTTG1.

LINC00460 accelerates progression of ovarian cancer by activating transcriptional factor ZNF703

Potential function of LINC00460 in the progression of ovarian cancer (OC) and its underlying mechanism were studied. LINC00460 level in OC tissues and normal ovarian tissues was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Correlation between LINC00460 level with tumor stage, tumor size and pathological subtypes of OC was analyzed. Potential influence of LINC00460 on proliferative ability and cell cycle progression was evaluated. In vivo tumorigenesis model was conducted by administration of A2780 cells transfected with sh-NC or sh-LINC00460 in nude mice. Predicted through JASPAR database, ZNF703 was screened out as the transcriptional factor binding to LINC00460 promoter region. Chromatin immunoprecipitation (ChIP) assay was performed to verify the binding relationship between ZNF703 and LINC00460. The potential role of ZNF703 in LINC00460-mediated OC progression was examined. LINC00460 was upregulated in OC tissues and cell lines. Its level increased with the deterioration of tumor stage and enlargement of tumor size. LINC00460 was highly expressed in serous ovarian cancer relative to other subtypes of OC. Knockdown of LINC00460 attenuated proliferative ability and arrested cell cycle of A2780 and HO8910 cells. ZNF703 was upregulated in OC tissues. ChIP assay showed pronounced enrichment of LINC00460 in ZNF703. Rescue experiments revealed that ZNF703 overexpression reversed the regulatory effects of LINC00460 on cellular behavior of OC cells. LINC00460 is upregulated in OC tissues and cell lines, which is closely related to tumor progression. It accelerates proliferative ability and cell cycle progression of OC cells via interacting with ZNF703.

Long Noncoding RNA LINC01125 Enhances Cisplatin Sensitivity of Ovarian Cancer via miR-1972

Background

Ovarian cancer (OC) is the most frequent aggressive cancer among women worldwide, and chemoresistance is the major challenge in the clinical treatment of OC. Recently, there is evidence that long noncoding RNAs (lncRNAs) are closely related to the regulation of cisplatin (CDDP) resistance in OC cells. However, whether LINC01125, a novel lncRNA, can improve the sensitivity of OC to cisplatin remains unknown.

Material/Methods

In this study, we analyzed aberrantly expressed lncRNAs in miR-200a-overexpressing OC samples by using GSE122123. LINC01125 and miR-1972 expressions were measured by qRT-PCR. The effect of LINC01125 overexpression on cell proliferation was determined by CCK-8 and colony formation assays. The sensitivity of OC cells to cisplatin was determined by CCK-8 assays. The interaction between LINC01125 and miR-1972 was verified through dual-luciferase reporter and RNA immunoprecipitation (RIP) assays, and bioinformatics analysis was performed to predict the target genes of miR-1972.

Results

Our results indicated that LINC01125 expression was significantly downregulated in CDDP-resistant OC tissues and cell lines. Overexpression of LINC01125 inhibited OC cell proliferation and enhanced the cytotoxicity of CDDP in OC cells. Additionally, LINC01125 participated in the apoptosis pathway by directly binding to miR-1972 in OC cells.

Conclusions

Therefore, we suggest that LINC01125 might act as a tumor suppressor in OC and enhances the cisplatin sensitivity of OC cells by binding to miR-1972.

LncRNA ZEB1-AS1 down-regulation suppresses the proliferation and invasion by inhibiting ZEB1 expression in oesophageal squamous cell carcinoma

Multiple studies have unveiled that long non‐coding RNAs (lncRNAs) play a pivotal role in tumour progression and metastasis. However, the biological role of lncRNA ZEB1‐AS1 in oesophageal squamous cell carcinoma (ESCC) remains under investigation, and thus, the current study was to investigate the functions of ZEB1‐AS1 in proliferation and invasion of ESCC. Here, we discovered that ZEB1‐AS1 and ZEB1 were markedly up‐regulated in ESCC tissues and cells relative to their corresponding normal control. ZEB1‐AS1 and ZEB1 overexpressions were both related to TNM staging and lymph node metastasis as well as poor prognosis in ESCC. The hypomethylation of ZEB1‐AS1 promoter triggered ZEB1‐AS1 overexpression in ESCC tissues and cells. In addition, ZEB1‐AS1 knockdown mediated by siRNA markedly suppressed the proliferation and invasion in vitro in EC9706 and TE1 cells, which was similar with ZEB1 siRNA treatment, coupled with EMT alterations including the up‐regulation of E‐cadherin level as well as the down‐regulation of N‐cadherin and vimentin levels. Notably, ZEB1‐AS1 depletion dramatically down‐regulated ZEB1 expression in EC9706 and TE1 cells, and ZEB1 overexpression obviously reversed the inhibitory effects of proliferation and invasion triggered by ZEB1‐AS1 siRNA. ZEB1‐AS1 shRNA evidently inhibited tumour growth and weight, whereas ZEB1 elevation partly recovered the tumour growth in ESCC EC9706 and TE1 xenografted nude mice. In conclusion, ZEB1‐AS1 overexpression is tightly involved in the development and progression of ESCC, and it exerts the antitumour efficacy by regulating ZEB1 level in ESCC.

Overexpression of long noncoding RNA HOXB-AS3 indicates an unfavorable prognosis and promotes tumorigenesis in epithelial ovarian cancer via Wnt/β-catenin signaling pathway

Long noncoding RNA HOXB cluster antisense RNA 3 (HOXB-AS3) has been reported to be dysregulated in several tumors. The present study mainly aims at the investigation in how HOXB-AS3 works in epithelial ovarian cancer (EOC) and to elucidate the mechanism involved. Initially, 'GEPIA' was mined to examine the differential expression levels and prognostic value of HOXB-AS3 in EOC patients. The expression of HOXB-AS3 in EOC cell lines and patient specimens was examined with quantitative RT-PCR. Simultaneously, the correlation of HOXB-AS3 expression with a variety of clinicopathological factors and patient survival was analyzed. MTT, colony formation and flow cytometry assays were performed to analyze the cell viability of EOC cells. Wound healing and Transwell assays were carried out to determine EOC cells' capability of migrating and invading. The impact of HOXB-AS3 on EMT and Wnt/β-catenin signaling was explored with the approach of Western blot. We found that in both EOC cell lines and tissues, HOXB-AS3 expression was significantly up-regulated, and its high expression was an independent prognostic marker of poor outcome for EOC patients. In vitro loss-of-function assays revealed that HOXB-AS3 knockdown inhibited EOC cells proliferation, migration, invasion and EMT, and induced EOC cells' apoptosis. Furthermore, we validated that down-regulated HOXB-AS3 attenuated the activity of Wnt/β-catenin signaling to suppress the invasion, migration and proliferation of EOC cells. To sum up, the present study came up with the conclusion that HOXB-AS3 acts as an oncogenic gene in EOC progression through HOXB-AS3-Wnt/β-catenin signaling regulation, providing a novel insight into EOC tumorigenesis.

Integrative analysis of long noncoding RNA and mRNA reveals candidate lncRNAs responsible for meat quality at different physiological stages in Gushi chicken

Long noncoding RNAs (lncRNAs) play important roles in transcriptional and posttranscriptional regulation. However, the effects of lncRNAs on the meat quality of chicken hasn’t been elucidated clearly yet. Gushi chickens are popular in China because of their superior meat quality, particularly the tender flesh, and unique flavor. Gushi chickens are popular in China because of their superior meat quality, delicate flesh, and unique flavor. We performed RNA-Seq analysis of breast muscle from Gushi chicken at two physiological stages, including juvenile (G20W) and laying (G55W). In total, 186 lncRNAs and 881 mRNAs were differentially expressed between G20W and G55W (fold change ≥ 2.0, P < 0.05). Among them, 131 lncRNAs presented upregulated and 55 were downregulated. We identified the cis and trans target genes of the differentially expressed lncRNAs, and constructed lncRNA-mRNA interaction networks. The results showed that differentially expressed mRNAs and lncRNAs were mainly involved in ECM-receptor interaction, glycerophospholipid metabolism, ubiquitin-mediated proteolysis, and the biosynthesis of amino acids. In summary, our study utilized RNA-seq analysis to predict the functions of lncRNA on chicken meat quality. Furthermore, comprehensive analysis identified lncRNAs and their target genes, which may contribute to a better understanding of the molecular mechanisms underlying in poultry meat quality and provide a theoretical basis for further research.

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

INTRODUCTION

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

LINC01857 as an oncogene regulates CREB1 activation by interacting with CREBBP in breast cancer

Breast cancer is a one of the most malignant threats among women worldwide. However, the mechanism underlying breast cancer development remains unclear. Long noncoding RNAs (lncRNAs) have been reported to participate in breast cancer. Whether lncRNA LINC01857 is involved in breast cancer requires investigation. In this study, we found that LINC01857 was highly expressed in breast cancer tissues and cells (p < 0.05). High LINC01857 expression predicted poor prognosis in breast cancer patients. Functionally, LINC01857 silencing impaired proliferation and enhanced apoptosis of breast cancer cells ( p < 0.05). Decreased LINC01857 inhibited breast cancer cells migration and invasion ability ( p < 0.05). In terms of mechanism, LINC01857 promoted H3K27Ac deposition on CREB1 promoter and initiated its transcription by recruiting CREBBP. Overexpression of CREB1 reversed the biological behavior of breast cancer cells induced by LINC01857 silencing ( p < 0.05). Taken together, our findings demonstrated that LINC01857 promoted breast cancer development by promoting H3K27Ac and CREB1 transcription via enhancing CREBBP enrichment in the CREB1 promoter region.

LncRNA LINC00319 accelerates ovarian cancer progression through miR-423-5p/NACC1 pathway

Long noncoding RNA (lncRNA) LINC00319 has been reported to promote carcinogenesis of lung cancer and cutaneous squamous cell carcinoma. However, the role and mechanism of LINC00319 in ovarian cancer progression is unclear. In this study, LINC00319 expression was found to be upregulated in ovarian cancer tissues and cell lines. And our evidence showed that LINC00319 could be a potential prognostic biomarker for patients with ovarian cancer. Cell Counting Kit-8 (CCK-8), colony formation and transwell assays indicated that LINC00319 upregulation promoted proliferation, migration and invasion of ovarian cancer cells. Bioinformatics analysis and luciferase reporter assay revealed that LINC00319 worked as the sponge for miR-423-5p. Furthermore, miR-423-5p directly targeted NACC1. qRT-PCR and western blot results demonstrated that LINC00319 upregulates NACC1 expression through inhibiting miR-423-5p in ovarian cancer cells. Moreover, we observed an inverse expression correlation between miR-423-5p and LINC00319 or between miR-423-5p and NACC1 in ovarian cancer tissues. Finally, rescue assay showed that NACC1 restoration rescued the potentials of proliferation, migration and invasion in LINC00319-depleted ovarian cancer cells. In conclusion, our findings demonstrated that LINC00319 promotes ovarian cancer progression through upregulating NACC1 expression by restraining miR-423-5p.

RETRACTED: Long non-coding RNA LINC00460 promotes epithelial ovarian cancer progression by regulating microRNA-338-3p

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief and the authors. Panels from Figures 2C and 2D appear similar to panels from Figures 4D and 4F of the article published by Hai-Xiang Yu, Xiao-Long Wang, Le-Ning Zhang, Ji Zhang and Wei Zhao in Biomedicine & Pharmacotherapy 109 (2019) 751-761 https://doi.org/10.1016/j.biopha.2018.09.110. Panels from Figure 3B appear similar to panels from Figure 3D of the article previously published by Yuanyuan Meng, Qi Li, Lianwei Li and Rong Ma in Biological Chemistry 399 (2017) 93-100 https://doi.org/10.1515/hsz-2017-0199. The ‘GAPDH’ Western Blots from Figure 3C appear similar to the ‘AKT’ Western Blots from Figure 6 of the article previously published by Lan Wu, Bo Shi, Kexin Huang and Guoyu Fan in the Oncology Reports 34 (2015) 2797-2805 https://doi.org/10.3892/or.2015.4251 and the ‘GAPDH’ Western Blots from Figure 4D of the article previously published by Tao Peng, Lixiang Zhou, Ling Zuo and Yongxin Luan in the Oncology Reports 35 (2016) 1057-1064 https://doi.org/10.3892/or.2015.4406.

Long non-coding RNA: its evolutionary relics and biological implications in mammals: a review

The central dogma of gene expression propounds that DNA is transcribed to mRNA and finally gets translated into protein. Only 2–3% of the genomic DNA is transcribed to protein-coding mRNA. Interestingly, only a further minuscule part of genomic DNA encodes for long non-coding RNAs (lncRNAs) which are characteristically more than 200 nucleotides long and can be transcribed from both protein-coding (e.g. H19 and TUG1) as well as non-coding DNA by RNA polymerase II. The lncRNAs do not have open reading frames (with some exceptions), 3`-untranslated regions (3’-UTRs) and necessarily these RNAs lack any translation-termination regions, however, these can be spliced, capped and polyadenylated as mRNA molecules. The flexibility of lncRNAs confers them specific 3D-conformations that eventually enable the lncRNAs to interact with proteins, DNA or other RNA molecules via base pairing or by forming networks. The lncRNAs play a major role in gene regulation, cell differentiation, cancer cell invasion and metastasis and chromatin remodeling. Deregulation of lncRNA is also responsible for numerous diseases in mammals. Various studies have revealed their significance as biomarkers for prognosis and diagnosis of cancer. The aim of this review is to overview the salient features, evolution, biogenesis and biological importance of these molecules in the mammalian system.

The emerging roles of long non-coding RNA in gallbladder cancer tumorigenesis

Accumulating evidence suggests that long non-coding RNAs (lncRNAs) have important regulatory functions in gallbladder cancer (GBC) tumorigenesis and can serve as potential novel markers and/or targets for GBC. In this review, we critically discuss the emerging alteration of lncRNAs in GBC, the lncRNAs induced epigenetic regulation, the interaction of lncRNAs with microRNAs and lncRNAs effects on tumor-related signaling pathways. Additionally, contributions of lncRNAs in epithelial-mesenchymal transition process and energy metabolism reprogramming in GBC are also addressed. This may pave new ways towards the determination of GBC pathogenesis and lead to the development of new preventive and therapeutic strategies for GBC.

Knockdown of long noncoding RNA urothelial carcinoma-associated 1 inhibits cell viability, migration, and invasion by regulating microRNA-182 in gastric carcinoma

BACKGROUND

Long noncoding RNA urothelial carcinoma-associated 1 (UCA1) has been reported to be a vital mediator in various cancers. But, in terms of gastric cancer (GC), the effects of UCA1 on GC cell proliferation, migration, invasion, and apoptosis remain unclear. This study aimed to uncover the potential regulatory mechanism of UCA1 in GC cells.

METHODS

The expression level of UCA1 was first examined in the five different cell lines of HEK293, CCL-153, HUVEC, SUN-216, and SGC-7901 using a reverse-transcriptase quantitative polymerase chain reaction. Then, the vectors of short hairpin UCA1, the microRNA-182 (miR-182) mimic/inhibitor, and the pEX-tissue inhibitor of metalloproteinases 2 (TIMP2)/small interfering TIMP2 were transfected into SUN-216 and SGC-7901 cells to alter UCA1, miR-182, and TIMP2 expression. To investigate the biological functions, cell viability, migration, invasion, and apoptosis were examined by Cell Counting Kit-8, Transwell, and flow cytometry. The key factors of apoptosis and phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase 3β (GSK3β) and nuclear factor κB (NF-κB) signal pathways were determined by Western blot analysis.

RESULTS

UCA1 was upregulated in SUN-216 and SGC-7901 cells than in the other three cell lines of HEK293, CCL-153, and HUVEC. Knockdown of UCA1 significantly suppressed cell viability, migration, and invasion, and promoted apoptosis by regulating B-cell lymphoma 2, Bax, and cleaved-caspase-3/9 expressions. However, miR-182 overexpression markedly reversed the regulatory effect of UCA1 knockdown on SUN-216 and SGC-7901 cells. TIMP2 was a direct target gene of miR-182, and TIMP2 overexpression exhibited the same effect of UCA1 knockdown on cell viability, migration, invasion, and apoptosis. Besides, miR-182 activated PI3K/AKT/GSK3β and NF-κB signal pathways by regulation of TIMP2.

CONCLUSION

Knockdown of UCA1 exerts an anticancer effect on GC cells by regulating miR-182.

Long non-coding RNA PVT1 promotes cell proliferation and invasion through regulating miR-133a in ovarian cancer

The long non-coding RNA, plasmacytoma variant translocation 1 (PVT1), was reportedly to be highly expressed in a variety of tumors including ovarian cancer (OC). However, the role and mechanism of action of PVT1 in the carcinogenesis and progression of OC remains largely unknown. PVT1 and miR-133a expression were detected by quantitative real time PCR(qRT-PCR) assays in OC tissues and cell lines. Cell Counting Kit-8 (CCK-8), flow cytometer, wound healing and transwell invasion assays were performed to evaluate cell proliferation, cycle, migration and invasion abilities, respectively. qRT-PCR and luciferase reporter assays demonstrated PVT1 regulated miR-133a expression. Here, we discovered that PVT1 shows higher expression in OC tissues than in normal ovarian tissues, and patients who show higher expression of PVT1 have worse progression-free and overall survivals compared to lower expression of PVT1. Additionally, we observed that knockdown of PVT1 significantly inhibited OC cell proliferation, and decreased the migration and invasion capabilities of OC cells. Mechanistically, miR-133a was identified to serve as a direct downstream target of PVT1 in OC. Knockdown of PVT1 inhibited cell proliferation, migration and invasion through negative regulating miR-133a in OC cells. Taken together, our finding shows that PVT1 may be a novel biomarker for prognosis and a promising therapeutic target for OC.

Long non-coding RNA RP11-552M11.4 promotes cells proliferation, migration and invasion by targeting BRCA2 in ovarian cancer

The present study aimed to investigate the effect of long non‐coding RNA (lncRNA) RP11‐552M11.4 on cell proliferation, apoptosis, migration and invasion as well as its targeting genes in epithelial ovarian cancer (EOC) cells. LncRNA RP11‐552M11.4 expression was detected in 67 tumor tissues and paired adjacent tissues obtained from EOC patients. lncRNA RP11‐552M11.4 mimic/inhibitor plasmids were transferred into ovarian cancer cells (SKOV3, A‐2780) and normal ovarian epithelial cells (IOSE80 cells). In addition, rescue experiment was carried out by transferring BRCA2 inhibitor&lncRNA RP11‐552M11.4 inhibitor plasmids into SKOV3 and A‐2780 cells. qPCR, western blot, CKK‐8, Annexin V/propidium iodide (AV/PI), wound‐healing and Matrigel invasion assays were carried out to detect RNA expression, protein expression, cell proliferation, apoptosis, migration, and invasion, respectively. LncRNA RP11‐552M11.4 expression was elevated in tumor tissues compared with paired adjacent tissues and correlated with higher pathological grade, International Federation of Gynecology and Obstetrics stage and worse overall survival in EOC patients. LncRNA RP11‐552M11.4 promoted SKOV3 cell proliferation, migration and invasion whereas it inhibited apoptosis. Rescue experiment and luciferase reporter assay showed that lncRNA RP11‐552M11.4 regulated SKOV3 cells functions through binding BRCA2. Further experiments in A‐2780 cells also validated that lncRNA RP11‐552M11.4 induced A‐2780 cell proliferation while repressing apoptosis by targeting BRCA2. In addition, upregulation of lncRNA RP11‐552M11.4 increased IOSE80 cell proliferation, migration and invasion while decreasing apoptosis. In conclusion, lncRNA RP11‐552M11.4 correlates with worse prognosis, and promotes cell proliferation, migration, invasion, and inhibits cell apoptosis by down‐regulating BRCA2 in EOC.

Role of lncRNAs in ovarian cancer: defining new biomarkers for therapeutic purposes

Long noncoding RNAs (lncRNAs) are a class of noncoding RNA, involved in regulation of diverse physiological and pathological processes. Ovarian cancer is the leading cause of death among all gynecological malignancies in the world and its underlying mechanism is still unclear. LncRNAs exhibit multiple biological functions in various stages of ovarian cancer development. We will discuss and summarize the new and important lncRNAs and their involvement in disease, which might represent promising therapeutic targets. Therapeutic intervention based on silencing or functional inhibition of target lncRNAs will be beneficial for ovarian cancer patients.

Key Anti-Fibrosis Associated Long Noncoding RNAs Identified in Human Hepatic Stellate Cell via Transcriptome Sequencing Analysis

Hepatic fibrosis is the main pathological basis for chronic cirrhosis, and activated hepatic stellate cells (HSCs) are the primary cells involved in liver fibrosis. Our study analyzed anti-fibrosis long noncoding RNAs (lncRNAs) in activated human HSCs (hHSCs). We performed RNA sequencing (RNA-seq) and bioinformatics analysis to determine whether lncRNA expression profile changes between hHSCs activation and quiescence. Eight differentially expressed (DE) lncRNAs and three pairs of co-expression lncRNAs-mRNAs were verified by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR). A total of 34146 DE lncRNAs were identified in this study. Via gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, we found several DE lncRNAs regulated hHSC activation by participating in DNA bending/packaging complex, growth factor binding and the Hippo signaling pathway (p < 0.05). With lncRNA–mRNA co-expression analysis, three lncRNAs were identified to be associated with connective tissue growth factor (CTGF), fibroblast growth factor 2 (FGF2) and netrin-4 (NTN4). The quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) results of the eight DE lncRNAs and three pairs of co-expression lncRNAs–mRNAs were consistent with the RNA-seq data and previous reports. Several lncRNAs may serve as potential targets to reverse the progression of liver fibrosis. This study provides a first insight into lncRNA expression profile changes associated with activated human HSCs.

Role of miR-21 in the growth and metastasis of human salivary adenoid cystic carcinoma

Aberrant microRNA (miRNA/miR) expression has been reported in various cancer types. miR-21, which is considered to be a proto-oncogene and is frequently overexpressed in certain cancer types, has been implicated in tumorigenesis. The aim of the present study was to investigate the effect of miR-21 degradation on tumor progression and its potential mechanisms in human salivary adenoid cystic carcinoma (SACC) development. Results of reverse transcription-quantitative polymerase chain reaction analysis indicated that SACC cells with high metastatic potential (SACC-LM cells) exhibited a significantly higher expression of miR-21 compared with SACC cells with a lower metastatic potential (SACC-83 cells). In addition, following transfection of SACC-LM cells with miR-21 inhibitor, cell viability was reduced, which may be a result of reduced cell proliferation and metastasis, and the induction of apoptosis, as determined by Cell Counting Kit-8, wound healing, Matrigel invasion and flow cytometry assays. Furthermore, bioinformatics analysis indicated that programmed cell death 4 (PDCD4), phosphatase and tensin homolog deleted on chromosome ten (PTEN) and B-cell lymphoma (Bcl)-2 are potential target genes of miR-21. Therefore, western blotting was performed to investigate the expression of these proteins, and the results demonstrated that miR-21 expression level was negatively associated with PDCD4 and PTEN protein expression, and positively associated with Bcl-2 protein expression, in SACC-LM cells, indicating that miR-21 may promote SACC progression via PDCD4, PTEN and Bcl-2. In conclusion, the present study indicates that miR-21 may be a novel target for SACC therapy and provide a novel basis for the clinical treatment of SACC.