lncRNAs In Hepatocellular Carcinoma Research Articles

LncRNA MCM3AP-AS1 inhibits cell proliferation in cervical squamous cell carcinoma by down-regulating miRNA-93

Background: MCM3AP antisense RNA 1 (MCM3AP-AS1) is characterized as an oncogenic lncRNA in hepatocellular carcinoma and glioblastoma. We analyzed TCGA dataset and observed the down-regulation of MCM3AP-AS1 in cervical squamous cell carcinoma (CSCC). The present study was therefore performed to investigate the role of MCM3AP-AS1 in CSCC.Methods: A total of 64 female patients with CSCC (38–68 years old; mean age: 53.1 ± 6.5 years old) were enrolled in the present study. RT-qPCR was performed to evaluate gene expression. Methylation specific PCR (MSP) was performed to assess the methylation of miR-93 gene after the overexpression and silencing of MCM3AP-AS1. Cell transfections were performed to investigate the interactions between MCM3AP-AS1 and miR-93. Cell proliferation was assessed by CCK-8 assay.Results: The results showed that MCM3AP-AS1 was down-regulated in CSCC and predicted poor survival. The expression levels of MCM3AP-AS1 were inversely correlated with the expression levels of miR-93. Overexpression of MCM3AP-AS1 led to down-regulation of miR-93, while silencing of MCM3AP-AS1 played an opposite role in CSCC cells. Methylation-specific PCR revealed that MCM3AP-AS1 could positively regulate the methylation of miR-93 gene. Cell proliferation analysis showed that overexpression of MCM3AP-AS1 led to reduced proliferation rate of CSCC cells. Silencing of MCM3AP-AS1 played an opposite role and overexpression of miR-93 reduced the effects of overexpressing MCM3AP-AS1.Conclusions: Therefore, MCM3AP-AS1 may inhibit cell proliferation in CSCC by down-regulating miRNA-93.

LncRNA RUNX1-IT1 which is downregulated by hypoxia-driven histone deacetylase 3 represses proliferation and cancer stem-like properties in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is characterised by a hypoxic microenvironment and a high rate of heterogeneity and recurrence, and the presence of cancer stem cells (CSCs) in HCC may well explain both of these pathological properties. There is mounting evidence that long non-coding RNAs (lncRNAs) participate in carcinogenesis and maintain cancer stemness of HCC cells. However, the expression modes, regulatory mechanisms and potential roles of stemness-related lncRNAs in HCC are still obscure. LncRNA RUNX1-IT1 is the intronic transcript 1 of the RUNX1, which is also known as chromosome 21 open-reading frame 96 (C21orF96). Although the functions of the RUNX1 have been identified in different diseases, the function and its potential mechanisms of the lncRNA RUNX1-IT1 in HCC still remains to be largely unknown. In this study, we verified that the expression of LncRNA RUNX1-IT1 was decreased in GEO data set, HCC samples and correlated with unfavourable clinicopathologic characteristics and poor prognosis. RUNX1-IT1 repressed HCC cell proliferation, cell cycle progression, invasion and cancer stemness and induced apoptosis in vitro. Overexpression of RUNX1-IT1 impaired the growth, metastasis and stem-like features of HCC cells in vivo. Mechanistically, RUNX1-IT1 directly bound to miR-632 and acted as competing endogenous RNA to facilitate the expression of the miR-632 target gene GSK-3β and subsequently modulate the WNT/β-catenin pathway in HCC cells. Furthermore, hypoxia-driven histone deacetylase 3 (HDAC3), as an upstream regulatory mechanism, was critical for the downregulation of RUNX1-IT1 in HCC. Thus, lncRNA RUNX1-IT1, as a regulator of hypoxia, may function as a potential therapeutic target for conquering HCC.

M6A-mediated upregulation of LINC00958 increases lipogenesis and acts as a nanotherapeutic target in hepatocellular carcinoma

BackgroundLong non-coding RNAs (lncRNAs) possess significant regulatory functions in multiple biological and pathological processes, especially in cancer. Dysregulated lncRNAs in hepatocellular carcinoma (HCC) and their therapeutic applications remain unclear.MethodsDifferentially expressed lncRNA profile in HCC was constructed using TCGA data. LINC00958 expression level was examined in HCC cell lines and tissues. Univariate and multivariate analyses were performed to demonstrate the prognostic value of LINC00958. Loss-of-function and gain-of-function experiments were used to assess the effects of LINC00958 on cell proliferation, motility, and lipogenesis. Patient-derived xenograft model was established for in vivo experiments. RNA immunoprecipitation, dual luciferase reporter, biotin-labeled miRNA pull-down, fluorescence in situ hybridization, and RNA sequencing assays were performed to elucidate the underlying molecular mechanisms. We developed a PLGA-based nanoplatform encapsulating LINC00958 siRNA and evaluated its superiority for systemic administration.ResultsWe identified a lipogenesis-related lncRNA, LINC00958, whose expression was upregulated in HCC cell lines and tissues. High LINC00958 level independently predicted poor overall survival. Functional assays showed that LINC00958 aggravated HCC malignant phenotypes in vitro and in vivo. Mechanistically, LINC00958 sponged miR-3619-5p to upregulate hepatoma-derived growth factor (HDGF) expression, thereby facilitating HCC lipogenesis and progression. METTL3-mediated N6-methyladenosine modification led to LINC00958 upregulation through stabilizing its RNA transcript. A PLGA-based nanoplatform loaded with si-LINC00958 was developed for HCC systemic administration. This novel drug delivery system was controlled release, tumor targeting, safe, and presented satisfactory antitumor efficacy.ConclusionsOur results delineate the clinical significance of LINC00958 in HCC and the regulatory mechanisms involved in HCC lipogenesis and progression, providing a novel prognostic indicator and promising nanotherapeutic target.

LINC00355:8 promotes cell proliferation and migration with invasion via the MiR-6777-3p/Wnt10b axis in Hepatocellular Carcinoma.

Background: Recent studies have reported that various long non-coding RNAs (lncRNAs) promote hepatocellular carcinoma (HCC) progression, and our previous study indicated that lncRNA LINC00355:8 is overexpressed in HCC. However, the role of LINC00355:8 in HCC is unclear. The primary aim of this study was to explore the biological role of LINC00355:8 in HCC.Methods: Microarray analysis was performed to explore the aberrantly expressed lncRNAs in HCC compared with precancerous tissues. Real-time PCR and in situ hybridization were used to investigate the expression of LINC00355:8 in HCC tissues. CCK8, EdU, colony formation, wound healing and transwell assays were performed to analyse cell proliferation, migration and invasion. A xenograft tumour model was established to analyse the effect of LINC00355:8 on tumour growth in vivo. Luciferase assays were utilized to explore the binding sites between miR-6777-3p and other genes, such as LINC00355:8 and Wnt10b. After cell transfection, the protein expression levels of Wnt10b, β-catenin, E-cadherin, N-cadherin, c-Myc and Snail were determined by Western blotting.Results: The present study revealed that LINC00355:8 was significantly upregulated in HCC, promoted HCC cell proliferation, migration and invasion in vitro and enhanced tumour growth in vivo. LINC00355:8 regulated miR-6777-3p expression by acting as a ceRNA, and the expression of Wnt10b was negatively modulated by miR-6777-3p. Moreover, LINC00355:8 could activate the Wnt/β-catenin signalling pathway and promote EMT progression by inhibiting the miR-6777-3p/Wnt10b interaction in HCC.Conclusion: Our findings indicate that LINC00355:8 activates Wnt10b and promotes HCC progression via the suppression of miR-6777-3p, which may provide novel therapeutic targets for HCC.

Identification of Ten Long Noncoding RNAs as Biomarkers for Hepatocellular Carcinoma

Long-chain non-encoded RNAs (lncRNAs) are important in many life activities and can participate in the occurrence of hepatocellular carcinoma (HCC). Moreover, lncRNAs can be used as basis for developing new strategies to hinder liver cancer. To investigate the utility of lncRNAs in HCC as potential biomarkers for early detection and diagnosis, we mined genomic data from the Cancer Genome Atlas (TCGA), and analyzed the gene expressions from 374 tumor patients and 50 normal patients. The abnormal expressions of 387 differentially expressed lncRNAs (DElncRNAs) were identified from a total of 3099 lncRNAs. Moreover, 18 modules were divided based on WGCNA, and 2 of the 18 modules were positively correlated with stage and grade, and negatively correlated with survival time. Finally, 10 lncRNAs were found and their main functions are the enhancement of cellular metabolic capacity and cell proliferation. These 10 lncRNAs may serve as novel prognostic markers and therapeutic targets, and may help guide subsequent studies on HCC.

LncRNA ANRIL promotes cell growth, migration and invasion of hepatocellular carcinoma cells via sponging miR-144.

Antisense non-coding RNA in the INK4A locus (ANRIL) has been recognized as a cancer-related lncRNA in hepatocellular carcinoma previously. This study aimed to reveal the functional effects and mechanisms of ANRIL on hepatocellular carcinoma cells in vitro. The expression of ANRIL in hepatocellular carcinoma cell lines (MHCC97 and Li-7) and non-tumourigenic liver cell line THLE-3 was detected by qRT-PCR. The expression of ANRIL, miR-144 and PBX3 in hepatocellular carcinoma cells was altered simultaneously or respectively by vector/oligonucleotide transfection. Then, cell viability, migration, invasion, apoptotic cell rate, protein expression of apoptosis-related factors were assessed. The correlation between ANRIL, miR-144 and PBX3 was explored. ANRIL was highly expressed in MHCC97 and Li-7 cells when compared to THLE-3 cells. ANRIL overexpression promoted cell viability, migration, invasion and suppressed apoptosis of MHCC97 and Li-7 cells. ANRIL negatively regulated miR-144, and oncogenic effects of ANRIL were attenuated when miR-144 was overexpressed. PBX3 was a direct target of miR-144. miR-144 overexpression blocked PI3K/AKT and JAK/STAT signalling pathways via targeting PBX3. Our data documented that ANRIL promoted hepatocellular carcinoma cells growth, migration and invasion. One of the possible mechanisms responsible for the tumour-promoting actions is that ANRIL sponging miR-144 to derepress PBX3.

Roles and Regulation of Long Noncoding RNAs in Hepatocellular Carcinoma.

Next-generation sequencing has uncovered thousands of long noncoding RNAs (lncRNA). Many are reported to be aberrantly expressed in various cancers, including hepatocellular carcinoma (HCC), and play key roles in tumorigenesis. This review provides an in-depth discussion of the oncogenic mechanisms reported to be associated with deregulated HCC-associated lncRNAs. Transcriptional expression of lncRNAs in HCC is modulated through transcription factors, or epigenetically by aberrant histone acetylation or DNA methylation, and posttranscriptionally by lncRNA transcript stability modulated by miRNAs and RNA-binding proteins. Seventy-four deregulated lncRNAs have been identified in HCC, of which, 52 are upregulated. This review maps the oncogenic roles of these deregulated lncRNAs by integrating diverse datasets including clinicopathologic features, affected cancer phenotypes, associated miRNA and/or protein-interacting partners as well as modulated gene/protein expression. Notably, 63 deregulated lncRNAs are significantly associated with clinicopathologic features of HCC. Twenty-three deregulated lncRNAs associated with both tumor and metastatic clinical features were also tumorigenic and prometastatic in experimental models of HCC, and eight of these mapped to known cancer pathways. Fifty-two upregulated lncRNAs exhibit oncogenic properties and are associated with prominent hallmarks of cancer, whereas 22 downregulated lncRNAs have tumor-suppressive properties. Aberrantly expressed lncRNAs in HCC exert pleiotropic effects on miRNAs, mRNAs, and proteins. They affect multiple cancer phenotypes by altering miRNA and mRNA expression and stability, as well as through effects on protein expression, degradation, structure, or interactions with transcriptional regulators. Hence, these insights reveal novel lncRNAs as potential biomarkers and may enable the design of precision therapy for HCC.

Integrated bioinformatics analysis reveals role of the LINC01093/miR-96-5p/ZFAND5/NF-κB signaling axis in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a significant health burden worldwide and its pathogenesis remains to be fully elucidated. One of the means by which long non-coding (lnc)RNAs regulate gene expression is by interacting with micro (mi)RNAs and acting as competing endogenous (ce)RNAs. lncRNAs have important roles in various diseases. The aim of the present study was to examine the potential roles of lncRNAs in HCC. The RNA expression profiles of 21 paired tissues of HCC and adjacent non-tumor tissues were obtained from the Gene Expression Omnibus database. The differentially expressed RNAs were analyzed using the DESeq package in R. Expression validation and survival analysis of selected RNAs were performed using Gene Expression Profile Interactive Analysis and/or Kaplan-Meier Plotter. The target genes of the miRNAs were predicted using lncBase or TargetScan. Functional analyses were performed using the Database for Annotation, Visualization and Integrated Discovery, and regulatory networks were determined using Cytoscape. Long intergenic non-protein coding RNA 1093 (LINC01093) was identified as one of the most significantly downregulated lncRNAs in HCC tissues. Downregulated expression of LINC01093 was associated with poor prognosis. A ceRNA network involving LINC01093, miR-96-5p and zinc finger AN1-type containing 5 (ZFAND5) was established. According to functional analyses, NF-κB signaling was implicated in the regulatory network for HCC. The present study revealed that a LINC01093/miR-96-5p/ZFAND5/NF-κB signaling axis may have an important role in the pathogenesis of HCC, and further investigation of this axis may provide novel insight into the development and progression of HCC.

Comprehensive analysis of long non‑coding RNA‑messenger RNA‑microRNA co‑expression network identifies cell cycle‑related lncRNA in hepatocellular carcinoma.

Long non-coding RNAs (lncRNAs) have been shown to contribute to progression and prognosis of hepatocellular carcinoma (HCC). However, expression profiling and interaction of lncRNAs with messenger RNAs (mRNAs) and microRNAs (miRNAs) remain largely unknown in HCC. The expression profiling of lncRNAs, mRNA and miRNAs was obtained using microarray. The Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analysis were used to characterize potential functions of differentially expressed mRNAs. Cytoscape was applied to construct an lncRNA-miRNA-mRNA co-expression network and candidate lncRNAs were validated via quantitative PCR in 30 pairs of HCC and adjacent tumor-free tissues. In this study, 1,056 upregulated and 1,288 downregulated lncRNAs were identified, while 2,687 mRNAs and 6 miRNAs were aberrantly expressed in HCC compared with adjacent tumor-free tissues. Potential functions of differentially expressed mRNAs were demonstrated to significantly participate in modulating critical genes in the cell cycle, such as cyclin E1 and cyclin B2. After screening, 95 lncRNAs, 5 miRNAs and 36 mRNAs were recruited for construction of lncRNA-mRNA-miRNA co-expression network in the cell cycle pathway. Subsequently, the top 5 lncRNAs that potentially modulate critical genes in the cell cycle were selected as the candidates for further verification. Kaplan-Meier curves using the Cancer Genome Atlas database showed that 13 targeted mRNAs were associated with overall survival of HCC patients. Finally, three lncRNAs, including ENST00000522221, lnc-HACE1-6:1 and lnc-ICOSLG-11:1, are significantly upregulated in HCC tissues compared with adjacent tumor-free tissues. These findings suggest that lncRNAs play essential roles in the pathogenesis of HCC via regulating coding genes and miRNAs, and may be important targets for diagnosis and treatment of this disease.

LncRNA-PDPK2P promotes hepatocellular carcinoma progression through the PDK1/AKT/Caspase 3 pathway.

Hepatocellular carcinoma (HCC) is a malignancy with one of the worst prognoses. Long noncoding RNA (lncRNA) are emerging as an important regulator of gene expression and function, leading to the development of cancer. The aim of this study was to determine the relationship between lncRNA and HCC and to further guide clinical therapy. lncRNA in HCC and adjacent tissues were screened, and the correlation between lncRNA‐PDPK2P expression in liver tissues and the pathological characteristics and severity of HCC was assessed. The effects of PDPK2P on HCC proliferation, apoptosis, metastasis, and invasion were also systematically investigated via CCK‐8 assay, flow cytometry, scratch wound healing, and transwell assay, respectively. The relationship between PDPK2P and PDK1 was verified by RNA pull‐down, rescue experiments and western blot. lncRNA‐PDPK2P was highly expressed in HCC tissues with a distinct positive correlation between PDPK2P and PDK1, and the upregulation was clinically associated with a larger tumor embolus, low differentiation, and poor survival. Mechanistically, lncRNA‐PDPK2P interacted with PDK1 and promoted HCC progression through the PDK1/AKT/caspase 3 signaling pathway. lncRNA‐PDPK2P can promote HCC progression, suggesting it may be a clinically valuable biomarker and serve as a molecular target for the diagnosis, prognosis, and therapy of hepatocellular carcinoma.

LncRNA AWPPH participates in the metastasis of non-small cell lung cancer by upregulating TGF-β1 expression.

Long non-coding RNA (lncRNA) AWPPH is a characterized oncogenic lncRNA in hepatocellular carcinoma and bladder cancer. The aim of the present study was to investigate the potential involvement of AWPPH in non-small cell lung cancer (NSCLC). Expression of AWPPH in lung biopsy tissues and serum of both healthy controls and patients with NSCLC with different tumor sizes, and with and without distant tumor metastasis was detected by reverse transcription-quantitative PCR. AWPPH expression vector was constructed and transfected into cells of human NSCLC cell lines. Expression of TGF-β1 was detected by western blot analysis. Cell migration and invasion were detected by Transwell migration and invasion assay. It was observed that AWPPH was significantly upregulated in patients with NSCLC, while AWPPH expression level did not increase with the increase of tumor size. In contrast, AWPPH expression levels were significantly higher in patients with distant metastasis than in patients without tumor distant metastasis. AWPPH overexpression promoted TGF-β1 expression in NSCLC cells, while TGF-β1 treatment showed no significant effects on AWPPH expression. AWPPH overexpression promoted NSCLC cell migration and invasion, while TGF-β signaling inhibition reduced this enhancing effect. Therefore, AWPPH may promote the metastasis, but not the growth of NSCLC by upregulating TGF-β1 expression.

Identification of diagnostic long non‑coding RNA biomarkers in patients with hepatocellular carcinoma.

Liver cancer is a leading cause of cancer-associated mortality worldwide. Hepatocellular carcinoma (HCC) is the most common subtype of liver cancer. The aim of the present study was to identify long non-coding RNA (lncRNAs) as diagnostic biomarkers for HCC. The lncRNA and mRNA expression profiles of a large group of patients with HCC were obtained from The Cancer Genome Atlas. The differentially expressed lncRNAs (DElncRNAs) and the differentially expressed mRNAs (DEmRNAs) were identified by bioinformatics analysis. Using feature selection procedure and a classification model, the optimal diagnostic lncRNA biomarkers for HCC were identified. Classification models, including random forests, decision tree and support vector machine (SVM), were established to distinguish between HCC and normal tissues. DEmRNAs co-expressed with the lncRNAs were considered as targets of DElncRNAs. Functional annotation of DEmRNAs co-expressed with these lncRNAs biomarkers was performed. Receiver operating characteristic curve analysis of lncRNAs biomarkers was conducted. A total of 3,177 lncRNAs and 15,183 mRNAs between HCC and normal tissues were obtained. RP11-486O12.2, RP11-863K10.7, LINC01093 and RP11-273G15.2 were identified as optimal diagnostic lncRNA biomarkers for HCC that were co-expressed with 273, 69, 76 and 1 DEmRNAs, respectively. The area under the curve values of the random forest model, decision tree model and SVM model were 0.992, 0.927 and 0.992, and the specificity and sensitivity of the three models were 100.0 and 95.6, 92.0 and 98.3 and 98.0 and 97.2%, respectively. ‘PPAR signaling pathway’ and ‘retinol metabolism’ were two significantly enriched target pathways of DElncRNAs. The present study identified four DElncRNAs, including RP11-486O12.2, RP11-863K10.7, LINC01093 and RP11-273G15.2, as potential diagnostic biomarkers of HCC. Functional annotation of target DEmRNAs provided novel evidence for examining the precise roles of lncRNA in HCC.

LncRNA NEF inhibits migration and invasion of HPV-negative cervical squamous cell carcinoma by inhibiting TGF-β pathway.

LncRNA NEF was a recently identified tumor suppressor lncRNA in hepatocellular carcinoma. Our study aimed to explore the role of NEF in cervical squamous cell carcinoma (CSCC) patients. In the present study, expression of NEF in tumor tissue (cervical biopsies for healthy control) and serum of human papillomaviruses (HPV)-negative and HPV-positive CSCC patients as well as healthy controls was detected by qRT-PCR. Diagnostic and prognostic values of NEF for CSCC were evaluated by ROC curve and survival curve analysis, respectively. NEF expression vector was transfected into CSCC cells and the effects on cell migration and invasion as well as TGF-β1 expression were investigated by Transwell migration assay, Transwell invasion assay, and Western blot, respectively. We found that expression of NEF in cervical tissues (tumor tissues for CSCC patients) and serum was significantly down-regulated in HPV-negative CSCC patients than in healthy controls and HPV positive patients, but no significant differences were found between healthy controls and HPV positive patients. Low serum levels of NEF distinguished HPV-negative CSCC patients from healthy controls and indicated poor survival. NEF overexpression inhibited the migration and invasion of HPV-negative but not HPV-positive CSCC cells. NEF overexpression down-regulated TGF-β1 in HPV-negative CSCC cells but not in HPV-positive CSCC cells. TGF-β1 treatment reduced the effects of NEF overexpression on cell migration and invasion. Therefore, we conclude that lncRNA NEF may inhibit the migration and invasion of HPV-negative cervical squamous cell carcinoma by inhibiting TGF-β pathway.

LncRNA CACNA1G-AS1 facilitates hepatocellular carcinoma progression through the miR-2392/C1orf61 pathway.

Emerging studies have indicated that long noncoding RNAs (lncRNAs) possess various functions in initiating human cancers. However, the roleof lncRNAs in hepatocellular carcinoma (HCC) still remains ill understood. In this study, we sought to investigate the role of lncRNA CACNA1G-AS1 in HCC progression. Through bioinformatics analysis, we found that CACNA1G-AS1 expression was significantly upregulated in HCC tissues compared with that in the adjacent normal tissues. Moreover, CACNA1G-AS1 upregulation indicated poor prognosis in HCC patients. Knockdown of CACNA1G-AS1 attenuated the proliferation, migration, and invasion of HCC cells. Additionally, decreased expression of CACNA1G-AS1 prevented epithelial-mesenchymal transition. In vivo assay also showed that CACNA1G-AS1 silencing HCC cells havesmaller tumor volumes and weights. Further investigations demonstrated that CACNA1G-AS1 worked as a competing endogenous RNA to bind microRNA-2392 (miR-2392) and thereby alleviate the repression of the downstream target C1orf61. Collectively, CACNA1G-AS1 promotes HCC progression through regulating the miR-2392/C1orf61 pathway.

LncRNA DCST1-AS1 functions as a competing endogenous RNA to regulate FAIM2 expression by sponging miR-1254 in hepatocellular carcinoma.

Long non-coding RNAs (lncRNAs) play important roles in a variety of tumours; however, their biological function and clinical significance in hepatocellular carcinoma (HCC) are still unclear. In the present study, the clinical significance, biological function and regulatory mechanisms of lncRNA DCST1-AS1 in HCC were investigated. Differential lncRNAs in HCC were identified based on The Cancer Genome Atlas (TCGA) database. The biological function and mechanism of DCST1-AS1 were studied in vitro and in vivo LncRNA DCST1-AS1 was highly expressed in HCC tissues, and the high expression of DCST1-AS1 was significantly correlated with larger tumours and shorter survival time. Moreover, DCST1-AS1 knockout significantly inhibited proliferation, promoted apoptosis and cycle arrest of HCC cells, and inhibited tumour growth in vivo According to functional analysis, DCST1-AS1 competitively bound miR-1254, thus blocking the silencing effect of miR-1254 on the target gene Fas apoptosis inhibitor 2 (FAIM2). A novel lncRNA DCST1-AS1 that functions as an oncogene in HCC was discovered. DCST1-AS1 up-regulates the expression of FAIM2 by up-regulating the expression of miR-1254, ultimately promoting the proliferation of HCC cells. This research provides new therapeutic targets for HCC.

MIR210HG predicts poor prognosis and functions as an oncogenic lncRNA in hepatocellular carcinoma

MIR210HG is a novel long noncoding RNA (lncRNA) and has been found to be overexpresed in osteosarcoma and glioma. However, the level of MIR210HG and its clinical significance in hepatocellular carcinoma (HCC) are not well known. In results of our research, MIR210HG expression was increased in HCC tissue samples and cells compared with paired adjacent normal liver tissue samples and normal liver cell line respectively, and a good marker to discriminate HCC tissues from non-tumorous tissues. MIR210HG high-expression was correlated advanced clinical stage, big tumor size, present vascular invasion and unfavorable histological differentiation. The survival analysis from our cohort and TCGA cohort consistently suggested that HCC patients with MIR210HG high-expression had poorer prognosis than HCC patients with MIR210HG low-expression. Furthermore, univariate and multivariate Cox regression analyses showed that MIR210HG high-expression was an independent unfavorable prognostic factor for overall survival in HCC patients. The in vitro study showed that silencing of MIR210HG depressed HCC cell proliferation, migration and invasion. In conclusion, MIR210HG functions as an oncogenic lncRNA in HCC, and may be a potential biomarker for predicting clinical progression and prognosis.

Genome-wide screening identifies oncofetal lncRNA Ptn-dt promoting the proliferation of hepatocellular carcinoma cells by regulating the Ptn receptor

Oncofetal genes are genes that express abundantly in both fetal and tumor tissues yet downregulated or undetected in adult tissues, and can be used as tumor markers for cancer diagnosis and treatment. Meanwhile, long noncoding RNAs (lncRNAs) are known to play crucial roles in the pathogenesis of hepatocellular carcinoma (HCC), including tumor growth, proliferation, metastasis, invasion, and recurrence. We performed a genome-wide screening using microarrays to detect the lncRNA expression profiles in fetal livers, adult livers, and liver cancer tissues from mice to identify oncofetal lncRNAs in HCC. From the microarray data analysis, we identified lncRNA Ptn-dt as a possible oncofetal gene. Both in vitro and in vivo experiments results confirmed that overexpression of Ptn-dt significantly promoted the proliferation of mouse HCC cells. RNA pulldown assay showed that Ptn-dt could interact with the HuR protein. Interestingly, miR-96 binds with HuR to maintain its stability as well. Overexpression of lncRNA Ptn-dt led to the downregulation of miR-96, which might be due to the interaction between Ptn-dt and HuR. Meanwhile, previous studies have reported that Ptn can promote tumor growth and vascular abnormalization via anaplastic lymphoma kinase (Alk) signaling. In our study, we found that overexpression of Ptn-dt could promote the expression of Alk through repressing miR-96 via interacting with HuR, thus enhancing the biologic function of Ptn. In summary, a new oncofetal lncRNA Ptn-dt is identified, and it can promote the proliferation of HCC cells by regulating the HuR/miR-96/Alk pathway and Ptn-Alk axis.

LINC01554-Mediated Glucose Metabolism Reprogramming Suppresses Tumorigenicity in Hepatocellular Carcinoma via Downregulating PKM2 Expression and Inhibiting Akt/mTOR Signaling Pathway.

Background and Aims: Cancer cells prefer aerobic glycolysis to maintain growth advantages, but the role of long non-coding RNAs (lncRNAs) in glycometabolism still remains unclear. Here we identified one cytoplasmic lncRNA LINC01554 as a significantly downregulated lncRNA in hepatocellular carcinoma (HCC) and aimed to investigate its role in cellular glucose metabolism in the development and progression of HCC.Methods: Quantitative real-time PCR was used to determine the expression level of LINC01554. Downregulation of LINC01554 by miR-365a at transcriptional level was assessed by luciferase reporter assay. Subcellular fractionation assay and RNA fluorescence in situ hybridization were performed to detect the subcellular localization of LINC01554. RNA pull-down assay, mass spectrometry, and RNA immunoprecipitation assay were used to identify the underlying molecular mechanisms. The tumor-suppressive function of LINC01554 was determined by both in vitro assay and nude mice xenograft model.Results: LINC01554 was frequently downregulated in HCC, which was significantly associated with tumor invasion (P = 0.005), tumor size (P = 0.041), tumor staging (P = 0.023) and shorter survival (P = 0.035) of HCC patients. Luciferase reporter assay unraveled that LINC01554 was negatively regulated by miR-365a. Subcellular fractionation assay and RNA FISH revealed the cytoplasmic predominance of LINC01554 in MIHA cells and HCC clinical samples. Ectopic expression of LINC01554 inhibited HCC cell growth, colony formation in soft agar, foci formation, and tumor formation in nude mice. LINC01554 promoted the ubiquitin-mediated degradation of PKM2 and inhibited Akt/mTOR signaling pathway to abolish aerobic glycolysis in HCC cells. Further study found that LINC01554-knockout could effectively reverse the tumor-suppressive effect of LINC01554.Conclusions: Our results identify LINC01554 as a novel tumor suppressor in HCC and unravel its underlying molecular mechanism in reprogramming cellular glucose metabolism. LINC01554 could possibly serve as a novel prognostic biomarker and provide the rationale for HCC therapy.

LINC00707 contributes to hepatocellular carcinoma progression via sponging miR-206 to increase CDK14.

Recently, increasing numbers of long noncoding RNAs (lncRNAs) have been found to be aberrantly expressed in various cancers. However, the roles of lncRNAs in hepatocellular carcinoma (HCC) progression is largely unknown. In our current study, we identified that long intergenic nonprotein-coding RNA 707 (LINC00707) was remarkably elevated in HCC cells, indicating that LINC00707 was involved in HCC development. Subsequently, LINC00707 was significantly decreased in HepG2 and Huh7 cells. The in vitro functional assays demonstrated that knockdown of LINC00707 significantly reduced HCC cell proliferation, induced cell apoptosis, and blocked the cell cycle progression. In addition, HCC cell migration and invasion was also greatly inhibited by downregulation of LINC00707. Increasing evidence has indicated that lncRNAs can act as molecular sponges of microRNAs. Currently, we observed that microRNA-206 (miR-206) was dramatically inhibited in HCC cells and LINC00707 can modulate HCC development through sponging miR-206. The binding correlation between LINC00707 and miR-206 was confirmed by dual-luciferase reporter assay, RNA pull down and RNA immunoprecipitation assay in our study. Moreover, cyclin-dependent kinase 14 (CDK14) was predicted as a target of miR-206 and we found that miR-206 suppressed CDK14 levels in HCC cells. Finally, in vivo assays were used and it was proved that silence of LINC00707 can restrain HCC development through modulating miR-206 to upregulate CDK14. In conclusion, it was implied that LINC00707 can lead to HCC progression through sponging miR-206 and modulating CDK14.

LncRNA KTN1-AS1 promotes tumor growth of hepatocellular carcinoma by targeting miR-23c/ERBB2IP axis

Long non-coding RNAs (lncRNAs) are critical regulators in the tumorigenesis and metastasis of hepatocellular carcinoma (HCC). LncRNA KTN1 antisense RNA 1 (KTN1-AS1) has been reported to play an important role in colorectal cancer and correlates with unfavorable clinical outcomes of head and neck squamous cell carcinoma. However, the clinical significance and functional role of KTN1-AS1 in HCC are still unclear. Here, we found that KTN1-AS1 was a highly expressed lncRNA in HCC according to public available databases and our HCC cohort. Further analyses revealed that higher expression of KTN1-AS1 was observed in HCC tissues with large tumor size, high tumor grade and advanced TNM stage. Analysis of survival data indicated that high KTN1-AS1 expression was prominently correlated with poor clinical outcomes of HCC patients. Functionally, KTN1-AS1 knockdown suppressed cell proliferation and colony formation, and increased apoptosis of SMMC-7721 cells in vitro. Furthermore, silencing of KTN1-AS1 restrained tumor growth of HCC in vivo. Conversely, forced expression of KTN1-AS1 facilitated Huh7 cell proliferation and inhibited apoptosis. Mechanistically, KTN1-AS1 inversely regulated miR-23c abundance in HCC cells. Further evidence supported that KTN1-AS1 acted as a competing endogenous RNA (ceRNA) by directly sponging miR-23c in HCC cells. Interestingly, erbb2 interacting protein (ERBB2IP), a known target of miR-23c, was positively regulated by KTN1-AS1 and its restoration reversed KTN1-AS1 knockdown attenuated HCC cell growth. To conclude, our study sheds light on the novel function and underlying mechanism of KTN1-AS1 in HCC, which may accelerate the development of cancer therapy.