Long non-coding RNA Igf2as controls hepatocellular carcinoma progression through the ERK/MAPK signaling pathway

Exosomal CTCF Confers Cisplatin Resistance in Osteosarcoma by Promoting Autophagy via the IGF2-AS/miR-579-3p/MSH6 Axis

Cancer-derived exosomes participate in carcinogenesis and progression of cancers, including metastasis and drug-resistance. Of note, CTCF has been suggested to induce drug resistance in various cancers. Herein, we aim to investigate the role of cisplatin- (CDDP-) resistant osteosarcoma- (OS-) derived exosomal CTCF in OS cell resistance to CDDP and its mechanistic basis. Differentially expressed transcription factors, long noncoding RNAs (lncRNAs), miRNAs, and genes in OS were retrieved using bioinformatics approaches. Exosomes were extracted from CDDP-resistant OS cells and then cocultured with parental OS cells, followed by lentiviral transduction to manipulate the expression of CTCF, IGF2-AS, miR-579-3p, and MSH6. We assessed the in vitro and in vivo effects on malignant phenotypes, autophagy, CDDP sensitivity, and tumor formation of OS cells. It was established that CTCF and IGF2-AS were highly expressed in CDDP-resistant OS cells, and the CDDP-resistant OS cell-derived exosomal CTCF enhanced IGF2-AS transcription. CDDP-resistant OS-derived exosomes transmitted CTCF to OS cells and increased CDDP resistance in OS cells by activating an autophagy-dependent pathway. Mechanistically, CTCF activated IGF2-AS transcription and IGF2-AS competitively bound to miR-579-3p to upregulate MSH6 expression. Additionally, the promoting function of exosomal CTCF-mediated IGF2-AS/miR-579-3p/MSH6 in OS cell resistance to CDDP was confirmed in vivo. Taken together, CDDP-resistant OS-derived exosomal CTCF enhanced resistance of OS cells to CDDP via activating the autophagy-dependent pathway, providing a potential therapeutic consideration for OS treatment.

Role of lncRNA LINC01194 in hepatocellular carcinoma via the miR-655-3p/SMAD family member 5 axis

Long non-coding RNAs (lncRNAs) are involved in developing hepatocellular carcinoma (HCC). The present study explored the role of lncRNA LINC01194, which is upregulated in HCC tissues and might be a vital regulator in HCC progression. Levels of LINC01194, microRNA (miR)-655-3p, and SMAD family member 5 (SMAD5) were assessed using reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR). The bioactivity of Huh-7 cells was assessed using cell counting kit-8 and transwell assays and flow cytometry. Western blotting was conducted to measure the expression of invasion- and apoptosis-related proteins. The relationships between lncRNA LINC01194 and miR-655-3p, and miR-655-3p and SMAD5 were predicted using StarBase and TargetScan, and further verified using a dual-luciferase reporter assay. LINC01194 was overexpressed in HCC cells and in clinical samples. ILINC01194 silencing suppressed proliferation and migration; however, it promoted apoptosis in HCC cell lines. We also confirmed that miR-655-3p could bind to LINC01194, and miR-655-3p was downregulated in HCC. The upregulation of miR-655-3p suppressed HCC cell invasion and migration, and enhanced the number of apoptotic cells. SMAD5, which was overexpressed in HCC cell lines, was directly targeted by miR-655-3p. Therefore, LINC01194 promoted HCC development by decreasing miR-655-3p expression and may serve as a promising therapeutic target for HCC patients.

Downregulation of lncRNA IGF2-AS-encoded peptide induces trophoblast - cycle arrest

RESEARCH QUESTION

lncRNA IGF2-AS may be related to early pregnancy loss. Does lncRNA IGF2-AS affect trophoblast cell growth? The aim of the present study was to verify that lncRNA IGF2-AS encodes a polypeptide, IGF2-AS-168aa, and to study its role in the pathogenesis of trophoblasts.

DESIGN

A small interfering RNA targeted to the IGF2-AS gene (si-IGF2-AS) was designed and transfected into JEG-3 and JAR cells for in-vitro gene silencing. Quantitative polymerase chain reaction and western blotting were used to determine lncRNA IGF2-AS levels in experimental cells. After IGF2-AS suppression, MTT assay was used to assess cell proliferation and apoptosis was determined by flow cytometry. Target gRNA IGF2-AS-gRNA was designed for knockout conducted the corresponding mRNA. HEK293T cells were transfected with the identified positive clone vectors. Finally, IGF2-AS-168aa was analysed by western blotting after the protein-coding region of the IGF2-AS gene was knocked out by CRISPR/Cas9 gene-editing technology.

RESULTS

lncRNA IGF2-AS and IGF2-AS-168aa were significantly downregulated in JEG-3 and JAR cells transfected with si-IGF2-AS (lncRNA IGF2-AS: JAR: NC versus small interfering RNA (siRNA)-1: P = 0.019 NC versus siRNA-2: P = 0.013; JEG-3: NC versus siRNA-1: P = 0.001 NC versus siRNA-2: P = 0.004) (IGF2-AS-168aa: JAR: NC versus siRNA-1: P = 0.030 NC versus siRNA-2: P = 0.018; JEG-3: NC versus siRNA-1: P = 0.004 NC versus siRNA-2: P = 0.001). IGF2-AS gene was incapable of encoding IGF2-AS-168aa after the coding region was successfully knocked out in HEK293T cells. Flow cytometry and the MTT assay revealed that IGF2-AS gene silencing led to cell cycle block in the G1 phase, markedly decreasing cell proliferation and increasing apoptosis.

CONCLUSION

The IGF2-AS gene encoded a peptide with a potential function in trophoblast cell cycle arrest.

Long Non-coding RNA MAFG-AS1 Promotes Cell Proliferation, Migration, and EMT by miR-3196/STRN4 in Drug-Resistant Cells of Liver Cancer

Long non-coding RNAs (lncRNAs) have been shown to participate in the development and progression of several different types of cancer. Past studies indicated that lncRNA MAFG-antisense 1 (AS1) promotes colorectal cancer. However, the role of MAFG-AS1 in hepatocellular carcinoma (HCC) remains unclear. The aim of the present study is to examine the effect of lncRNA MAFG-AS1 on drug resistance HCC. The results indicated that MAFG-AS1 is upregulated in drug-resistant cells. Further, MAFG-AS1 promotes growth and migration of HCC by upregulating STRN4 through absorbing miR-3196. Thus, LncRNA MAFA-AS1 may become a novel target to treat HCC patients.

MAPK/ERK Signaling Pathway in Hepatocellular Carcinoma

Simple Summary

The mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway is frequently activated in liver cancer, which is one of the most lethal cancers in humans. In addition to genetic mutation leading to persistent activation of effector molecules in the MAPK/ERK signaling cascade, there are alternative means by which the MAPK/ERK signaling pathway is activated in cancer. In this review, we will introduce the diverse modulators regulating the MAPK/ERK signaling pathway and consider the possibility of targeting the effectors and regulators in order to suppress the pro-tumorigenic MAPK/ERK signaling pathway, especially in liver cancer.

Abstract

Hepatocellular carcinoma (HCC) is a major health concern worldwide, and its incidence is increasing steadily. Recently, the MAPK/ERK signaling pathway in HCC has gained renewed attention from basic and clinical researchers. The MAPK/ERK signaling pathway is activated in more than 50% of human HCC cases; however, activating mutations in RAS and RAF genes are rarely found in HCC, which are major genetic events leading to the activation of the MAPK/ERK signaling pathway in other cancers. This suggests that there is an alternative mechanism behind the activation of the signaling pathway in HCC. Here, we will review recent advances in understanding the cellular and molecular mechanisms involved in the activation of the MAPK/ERK signaling pathway and discuss potential therapeutic strategies targeting the signaling pathway in the context of HCC.

Comprehensive ceRNA network analysis and experimental studies identify an IGF2-AS/miR-150/IGF2 regulatory axis in colorectal cancer

Recently, a growing body of studies has demonstrated that long non-coding RNA (lncRNA) can act as microRNA (miRNA) sponges to regulate protein-coding gene expression and play essential roles in tumor initiation and progression. In the present study, we constructed a competitive endogenous RNA (ceRNA) network and identified potential regulatory axes in colorectal cancer (CRC) through both bioinformation and experimental validation. Firstly, we obtained differentially expressed (DE) lncRNAs, miRNAs, and mRNAs by analyzing the RNA expression profiles of CRC retrieved from The Cancer Genome Atlas (TCGA) database and CRC patients' data from affiliated Hospital of Jiangnan University, respectively. Then, we established a ceRNA regulatory network of CRC that includes 23 lncRNAs, 7 miRNAs and 244 mRNAs. To further identify these lncRNA-miRNA-mRNA regulatory axes which might play vital roles in CRC tumorigenesis and prognosis, we performed additional analyses using comprehensive bioinformatic methods. Several ceRNA regulatory axes, which consist of 2 lncRNAs, 2 miRNAs and 5 mRNAs, were obtained from the network. Finally, the interactions and correlations among these ceRNA networks were validated by experiments on CRC cell lines and clinical tumor tissues, and a potential IGF2-AS/miR-150/IGF2 axis that perfectly conform to the ceRNA theory was determined. According to the qRT-PCR results, miR-150 overexpression remarkably decreased IGF2-AS and IGF2 expression. Meanwhile, IGF2-AS expression was positively correlated with IGF2 expression in tumor tissue of CRC patients. Besides, dual luciferase reporter assays indicated that miR-150 could bound to IGF2-AS and the 3'UTR of and IGF2. In general, the constructed novel IGF2-AS/miR-150/IGF2 network might provide potential mechanisms of CRC development, and could act as a promising target for CRC treatment.

lncRNA IGF2-AS Promotes Cell Proliferation, Migration, and Invasion of Gastric Cancer by Modulating miR-937/EZH2 Axis

The article entitled, "lncRNA IGF2-AS Promotes Cell Proliferation, Migration, and Invasion of Gastric Cancer by Modulating miR-937/EZH2 Axis," by Zizi Li, Zhanyu Li, Zhijuan Zhong, Jianhui Zhou, Shenhao Huang, Wenying Zhou, and Jianfeng Xu (Cancer Biother Radiopharm epub 25 May 2020; Doi: 10.1089/cbr.2019.3275) is being officially retracted from the literature. The Editor-in-Chief of Cancer Biotherapy and Radiopharmaceuticals (CBR) received an email from the corresponding author of the article, Wenying Zhou, on September 7, 2020, indicating: "…this manuscript should no longer be published [because of] information from our superior and also after discussion with my research team, we want to repeat our experiment and then revise the [manuscript]. Our team has a lot of controversy about these results. In order to ensure the quality of the data and not to mislead readers, we decided to [retract] the manuscript. We will be more rigorous in our further study." The editor requested further information about precisely which data could not be reproduced, to which Dr. Wenying Zhou responded: "…we found that the results of Figure 4B and 4C, Figure 5A and 5B could not be repeated. Our repeated results of Figure 4B and 4C were as follow[s]: compared with miR-NC group, there was no significant decrease of the luciferase activity in miR-937 group when cells co-transfected with EZH2 3'-UTR-WT. Our repeated results of Figure 5A and 5B were as follow[s]: miR-937 inhibited the proliferation of MNK-28 and SGC-7901 cells, but the cell proliferation had no significant change in miR-937+EZH2 group compared with miR-937+pcDNA group. These findings resulted in the uncertainty of the targeted relationship between miR-937 and EZH2. We also repeated these experiments in different environments, but they all contradict the results in the original data. So, the conclusion is very controversial. In a responsible attitude to the readers, we decide to [retract] the manuscript." The authors have extended their apologies to the Editor and to the readers of CBR. Though in the author's original email, the request was made to "withdraw" the paper, CBR has decided to fully retract it due to irreproducible data, as the journal is committed to preserving the scientific literature and the community it serves.

14,15β-dihydroxyklaineanone inhibits HepG2 cell proliferation and migration through p38MAPK pathway

OBJECTIVES

Eurycoma longifolia Jack (Simaroubaceae) is commonly distributed in the Southeast Asia and Indo China, which has been shown to possess antianxiety, antibacterial, anticancer, antifungal, anti-inflammatory, antimalarial and antioxidant biological activities. 14,15β-dihydroxyklaineanone is a diterpene isolated from E. longifolia Jack, which is cytotoxic against human lung cancer and human breast cancer cell lines. However, the effects and underlying mechanisms of 14,15β-dihydroxyklaineanone on hepatocellular carcinoma remain unknown.

METHODS

Cell viability assay and colony formation assay were used to measure HepG2 cell proliferation. Flow cytometry was used to analyse cell cycle and apoptosis. Wound-healing assay and transwell assay were used to observe cells migration. RNA sequencing and the enrichment of differentially expressed genes (DEGs) in Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were used to find and determine underlying pathways.

KEY FINDINGS

We found that 14,15β-dihydroxyklaineanone inhibited the growth and migration of HepG2 cells but did not induce cell apoptosis. 14,15β-dihydroxyklaineanone induced S cell cycle arrest by downregulating the expression levels of cyclin A, p-CDK2, cyclin B1, p21, E2F-1 and PCNA. In addition, RNA sequencing showed that 14,15β-dihydroxyklaineanone regulated MAPK pathway by increasing the expression levels of phosphor-p38. Downregulating of p38 via both p38 inhibitor (SB203580) and p38-siRNA could antagonize the inhibition of cell proliferation and migration and reverse the changes in p-p38, E-cadherin, N-cadherin and PCNA expression induced by 14,15β-dihydroxyklaineanone treatment.

CONCLUSIONS

14,15β-dihydroxyklaineanone inhibited cell proliferation and migration through regulating p38 MAPK pathway in HCC cells.

Ubiquitin specific peptidase 19 is a prognostic biomarker and affect the proliferation and migration of clear cell renal cell carcinoma

Ubiquitin specific peptidase 19 (USP19) is a member of the USP family and exhibits diverse roles in various biological processes, such as cell differentiation, cell cycle progression and apoptosis. There is limited knowledge regarding the role and impact of USP19 in cancer, particularly clear cell renal cell carcinoma (ccRCC). To examine the function of USP19 in ccRCC, The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus databases were examined to determine USP19 mRNA expression levels. USP19 mRNA levels were significantly lower in ccRCC tissues than in normal tissues. USP19 downregulation was associated with ccRCC progression and poor prognostic outcomes in TCGA cohort. Furthermore, the functional involvement of USP19 in ccRCC was examined using Cell Counting Kit-8, soft agar, Transwell and wound healing assays in vitro following overexpression or knockdown of USP19 in the Caki-1 cell line. USP19 overexpression inhibited ccRCC proliferation and migration, whereas USP19 knockdown promoted ccRCC proliferation and migration in vitro. Consistent with these results, it was further demonstrated that USP19 downregulation promoted tumor growth in vivo in a xenograft model. Mechanistically, it was found that USP19 exerted its inhibitory effect on ccRCC proliferation and migration by suppressing the activation of ERK. Collectively, the present findings identified a role for USP19 as a tumor suppressor in ccRCC and demonstrated that USP19 is a potential prognostic biomarker that could be applied in ccRCC therapy.

Down-regulation of lncRNA LINC00152 Suppresses Gastric Cancer Cell Migration and Invasion Through Inhibition of the ERK/MAPK Signaling Pathway

Purpose

The aim of this study was to explore the regulatory role and mechanism of long noncoding RNA LINC00152 in gastric cancer (GC) cells.

Methods

LINC00152 expression in GC tissues and cells was detected by reverse transcription-polymerase chain reaction (qRT-PCR). MKN45 and MGC-803 cells were selected and assigned into different groups after transfection with si-LINC00152, activated ERK/MAPK signaling pathway (SA), or negative control. Cell proliferation, apoptosis, cycle, migration and invasion were assessed by CCK-8, flow cytometry, Transwell assay and Scratch test, respectively. Western blot analysis was conducted to detect the expression of E-cadherin, N-cadherin and ERK/MAPK signaling pathway protein.

Results

Compared with the normal tissues, higher expression of LINC00152 was found in GC tissues and LINC00152 was remarkably correlative with clinical stage and lymphatic metastasis. LINC00152 expression in GC cells was higher than that in GES-1 cells. Compared with the NC group, the cell proliferation rate, cells in G2/M phase, migration and invasion abilities as well as the expression of N-cadherin and p-ERK-1/2 were significantly decreased, and the expression of E-cadherin, cells in G0/G1 phase and cell apoptosis rate were significantly increased in the si-LINC00152-1 group. ERK/MAPK signaling pathway activator SA could reverse the biological role of LINC00152 in GC cells.

Conclusion

These results demonstrated that the interference of LINC00152 expression may inhibit the invasion and migration of GC cells by inhibiting the ERK/MAPK signaling pathway.

IGF2-AS affects the prognosis and metastasis of gastric adenocarcinoma via acting as a ceRNA of miR-503 to regulate SHOX2

Disorder of long non-coding RNAs (LncRNAs) is found in various types of cancers and demonstrated to be associated with tumor occurrence and development. Our study found that lncRNA insulin growth factor 2 antisense (IGF2-AS) is up-regulated in gastric adenocarcinoma (GAC) tissues and correlated with poor prognosis in patients with GAC. Cell counting kit-8 (CCK8), colony formation, wound healing and transwell assays revealed that knockdown of IGF2-AS in BGC823 and SGC7901 cells significantly suppressed cell proliferation, migration and invasion. While, overexpression of IGF2-AS in AGS and MGC803 cells exhibited the opposite effects. RNA-FISH and subcellular fractionation assay found that most IGF2-AS was distributed in the cytoplasm, suggesting that IGF2-AS functioned as a potential ceRNA. RNA binding protein immunoprecipitation (RIP) assays further confirmed this assumption. By informatics prediction and luciferase reporter assay, we found that IGF2-AS functioned as an efficient miR-503 sponge and the level of miR-503 showed an inverse correlation with IGF2-AS. Short stature homeobox 2 (SHOX2) is predicted and verified as a target of miR-503. Moreover, IGF2-AS expression exhibited a negative correlation with miR-503 and a positive correlation with IGF2-AS. Subsequent rescue assay revealed that down-regulation of miR-503 or restoration of SHOX2 canceled IGF2-AS depletion-induced depression in proliferation and motility of BGC823 and SGC7901 cells. Meanwhile, up-regulation of miR-503 or down-regulation of SHOX2 decreased IGF2-AS overexpression induced promotion in proliferation and motility of AGS and MGC803 cells. In vivo tumorigenicity assay showed that knockdown of IGF2-AS significantly reduced tumor volume. Taken together, our results demonstrated that IGF2-AS takes important regulatory parts in GAC development by functioning as a ceRNA to regulate SHOX2 via sponging miR-503.

Modulation of cancer cell signaling by long noncoding RNAs

Cellular signaling pathways play a very important role in almost all molecular processes in the cell, and are generally composed of a complex set of cascades in which enzymes and proteins play a key role. These signaling pathways include different types of cellular signaling classified based on their receptors and effector proteins such as enzyme-linked receptors, cytokine receptors, and G-protein-coupled receptors each of which is subdivided into different classes. Signaling pathways are tightly controlled by different mechanisms mostly thorough inhibiting/activating their receptors or effector proteins. In the last two decades, our knowledge of molecular biology has changed dramatically and today we know that more than 85% of the human genome expresses noncoding RNAs most of which are crucial in the cellular and molecular mechanisms of cells. One of these noncoding RNAs are long noncoding RNAs (lncRNA) containing more than 200 nucleotides. LncRNAs participate in the progression of cancer growth through several mechanism including signaling pathways. In this review, we summarize some of the most important of lncRNAs and their effect on important signaling pathways.

Novel 1,4‑naphthoquinone derivatives induce reactive oxygen species‑mediated apoptosis in liver cancer cells

Derivatives of 1,4-naphthoquinone have excellent anti-cancer effects, but their use has been greatly limited due to their serious side effects. To develop compounds with decreased side effects and improved anti-cancer activity, two novel types of 1,4-naphthoquinone derivatives, 2,3-dihydro-2,3-epoxy-2-propylsulfonyl-5,8-dimethoxy-1,4-naphthoquinone (EPDMNQ) and 2,3-dihydro-2,3-epoxy-2-nonylsulfonyl-5,8-dimethoxy-1,4-naphthoquinone (ENDMNQ) were synthesized and their anti-tumor activities were investigated. The effects of EPDMNQ and ENDMNQ on cell viability, apoptosis and accumulation of reactive oxygen species (ROS) in liver cancer cells were determined by MTT cell viability assay and flow cytometry. The expression levels of mitochondrial, mitogen activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) signaling pathway-associated proteins in Hep3B liver cancer cells were analyzed by western blot analysis. The results demonstrated that EPDMNQ and ENDMNQ inhibited the proliferation of liver cancer Hep3B, HepG2, and Huh7 cell lines but not that of normal liver L-02, normal lung IMR-90 and stomach GES-1 cell lines. The number of apoptotic cells and ROS levels were significantly increased following treatment with EPDMNQ and ENDMNQ, and these effects were blocked by the ROS inhibitor N-acetyl-L-cysteine (NAC) in Hep3B cells. EPDMNQ and ENDMNQ induced apoptosis by upregulating the protein expression of p38 MAPK and c-Jun N-terminal kinase and downregulating extracellular signal-regulated kinase and STAT3; these effects were inhibited by NAC. The results of the present study demonstrated that EPDMNQ and ENDMNQ induced apoptosis through ROS-modulated MAPK and STAT3 signaling pathways in Hep3B cells. Therefore, these novel 1,4-naphthoquinone derivatives may be useful as anticancer agents for the treatment of liver cancer.

Deregulation of miR-520d-3p promotes hepatocellular carcinoma development via lncRNA MIAT regulation and EPHA2 signaling activation

MicroRNA-520d-3p (miR-520d-3p) is a novel cancer-related miRNA and functions as a tumor suppressor in human cancers. However, the expression patterns and mechanisms of miR-520d-3p involved in hepatocellular carcinoma (HCC) remain rarely known. Here, we found that the expression levels of miR-520d-3p in HCC tissues and cells were significantly lower than in tumor-adjacent tissues and L02 cells. Decreased level of miR-520d-3p was relevant to poor overall survival, whereas miR-520d-3p up-regulation resulted in a marked inhibition of cell growth, migration and invasion. In addition, the long non-coding RNA, myocardial infarction associated transcript (MIAT) was up-regulated in both HCC tissues and cell lines. MIAT suppressed the expression and function of miR-520d-3p. Moreover, erythropoietin-producing hepatocellular A2 (EPHA2) was speculated and confirmed as a direct target of miR-520d-3p. We also demonstrated that MIAT may function as a sponge competitive endogenous RNA for miR-520d-3p, and thus regulate the molecular expression of EPHA2. In summary, our study has identified a novel signaling pathway through which miR-520d-3p exerts its anticarcinogenic roles and suggested that the MIAT/miR-520d-3p/EPHA2 may be a new target for HCC therapy.

Overexpression of cancer susceptibility candidate 2 inhibited progression of hepatocellular carcinoma cells

OBJECTIVE

Our study was aimed to investigate the effect of cancer susceptibility candidate 2 (CASC2) on the proliferation, cell cycle, apoptosis, and metastasis of hepatocellular carcinoma (HCC) cells.

METHODS

CASC2 expression in tumor tissues and HCC cells was tested by quantitative real-time polymerase chain reaction. After manipulating the expression of CASC2 in Hep3B and HepG2 cells, cells viability, including proliferation, apoptosis, cell-cycle distribution, migration, and invasion were examined by colony formation assay, flow cytometry, wound-healing assay, and transwell assay, respectively. The expression levels of proteins associated with the cell cycle and AKT/mTOR pathway were measured by the western blot. Stably transfected HepG2 cells were used to construct nude mice models, and tumorigenesis was evaluated to investigate the in vivo functions of CASC2 in HCC progression.

RESULTS

In tissues and cells of HCC, decreased CASC2 expressions were confirmed. Overexpression of CASC2 made cell cycle stagnated at G0/G1 phase and induced apoptosis. Meanwhile, the overexpression of CASC2 played significant roles in inhibiting the proliferation, migration, and invasion of HCC cells. Furthermore, In vivo experiment indicated that CASC2 restrained the growth of tumors.

CONCLUSION

Our study suggested that CASC2 promoted cell apoptosis and suppressed cell growth and metastasis in HCC, indicating that CASC2 might be a useful biomarker of HCC.

LINC00707 promotes hepatocellular carcinoma progression through activating ERK/JNK/AKT pathway signaling pathway

Increasing evidence has demonstrated that abnormal expression of lncRNA is correlated with various malignant tumors, including hepatocellular carcinoma (HCC). Our current study was aimed to investigate the role of LINC00707 in HCC development. We observed that LINC00707 was upregulated in HCC cell lines compared with normal liver cell lines. Then, Hep3B cells and SNU449 cells were infected with LV-shLINC00707 and LV-LINC00707. LINC00707 silencing could greatly repress the proliferation and colony formation of HCC cells in vitro. On the contrary, overexpression of LINC00707 induced HCC cell proliferation and colony formation. In addition, HCC cell apoptosis was significantly enhanced and HCC cell cycle was blocked in G1 phase by LV-shLINC00707. Hep3B cells and SNU449 cell invasion capacity was restrained by the knockdown of LINC00707, whereas upregulation of LINC00707 exhibited an opposite phenomenon. Accumulating evidence has reported that ERK/JNK/AKT signaling is involved in multiple cancers, including HCC. Here, in our study, we identified that ERK/JNK/AKT signaling was dramatically restrained by silencing of LINC00707 while activated by LV-LINC00707 in HCC cells. Subsequently, an in vivo experiment was conducted, and it demonstrated that LINC00707 could modulate HCC development through activating ERK/JNK/AKT signaling. Taking the above results together, it was implied in our study that LINC00707 contributed to HCC progression through modulating the ERK/JNK/AKT pathway.

Long noncoding RNA DGCR5 represses hepatocellular carcinoma progression by inactivating Wnt signaling pathway

Increasing studies have indicated that long noncoding RNAs (lncRNAs) exert important roles in hepatocellular carcinoma (HCC). Therefore, it is of great significance to identify the dysregulated lncRNAs in HCC. According to the previous reports, it has been suggested that DiGeorge syndrome critical region gene 5 (DGCR5) might participate in HCC and can serve as potential biomarker for HCC. In our current study, we concentrated on the biological function and roles of lncRNA-DGCR5 in HCC. It was indicated that DGCR5 was decreased in HCC tissues and HCC cells including HepG2, Hep3B, MHCC-97L, SNU-449, and SNU-182 cells compared with the normal human liver cell line LO2. Overexpression of DGCR5 was able to restrain HCC growth, migration, and invasion capacity in HepG2 and SNU-449 cells. In addition, whether lncRNA-DGCR5 can regulate Wnt/β-catenin pathway during HCC progression is unclear. In our study, it was found that upregulation of DGCR5 inactivated Wnt signaling pathway through inhibiting β-catenin, cyclin D1 and increasing GSK-3β levels. Subsequently, in vivo tumor xenografts were established using HepG2 cells to investigate the function of DGCR5 in HCC development. Inconsistent with the in vitro findings, increase of DGCR5 dramatically suppressed HCC tumor progression in vivo. Taken these together, it was uncovered in our research that DGCR5 could play tumor suppressive role by targeting Wnt signaling in HCC progression.

Identification of ceRNA network based on a RNA-seq shows prognostic lncRNA biomarkers in human lung adenocarcinoma

Previous studies have emphasized the significant functions of long non-coding RNAs (lncRNAs) as competing endogenous RNAs (ceRNAs) in tumor biology. However, the functions of certain cancer lncRNAs in the lncRNA-related ceRNA network in lung adenocarcinoma (LUAD) are unknown. A systematic and integrative survey of RNA-seq data from The Cancer Genome Atlas (TCGA) was performed to identify candidate lncRNAs for the prognosis of LUAD. In total, 20,502 genes that contain 181 lncRNAs were evaluated in a cohort of 570 LUAD cases. Initially, 6,280 differentially expressed genes (fold-change >2, P<0.05) were obtained using R package, which includes 75 lncRNAs. Next, by univariate regression and multivariate Cox proportional hazards analysis, 32 genes were associated with survival in LUAD. Using these 29 mRNAs and 3 lncRNAs, a prognosis index (PI) was calculated to accurately estimate the survival in LUAD: PI=∑exp_{risk gene} × HRrisk gene. Furthermore, the 32-gene signature was an independent prognostic indicator for LUAD (HR >1; P<0.05, by multivariate analysis). Weighted gene co-expression network analysis (WGCNA) of three risk lncRNAs-FAM138B, NHEG1 and TLX1NB-was performed, based on the P-values of the associated genes, and the top 27 miRNAs that bound to these lncRNAs were predicted by Miranda as target miRNAs. Next, these target miRNAs were transferred to the TarBase, miRTarBase, miRecards and starBase v2.0 databases to obtain their target genes. According to the previous miRNA-mRNA and miRNA-lncRNA data, three lncRNA-miRNA-mRNA ceRNA networks were established, based on the 29 prognostic mRNAs, forming a regulatory network in LUAD. The present study provided insight into the lncRNA-related ceRNA network in LUAD and has identified potential diagnostic and prognostic biomarkers.

Prospects of Noncoding RNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a global health problem and one of the most common malignant tumors. Recent studies have shown that noncoding RNAs (ncRNAs) contribute to the pathogenesis of hepatocellular carcinoma (HCC). These RNAs may be involved in a variety of pathological processes such as cell proliferation, apoptosis, angiogenesis, invasion, and metastasis. In addition, abnormal expression of ncRNAs in HCC may provide potential prognostic or diagnostic biomarkers. This review provides an overview of the role and potential applications of ncRNAs, miRNAs, lncRNAs, circRNAs, and snoRNAs in liver cancer.

Long Noncoding RNA LINC003121 Inhibits Proliferation and Invasion of Thyroid Cancer Cells by Suppression of the Phosphatidylinositol-3-Kinase (PI3K)/Akt Signaling Pathway

BACKGROUND The aim of this study was to explore the potential effects of long noncoding RNA (lncRNA) LINC003121 on thyroid cancer (TC) cell proliferation and invasion and to explore their possible mechanisms with the involvement of the PI3K/Akt signaling pathway. MATERIAL AND METHODS We enrolled 211 thyroid cancer tissues and 70 adjacent normal tissues in this study. TC cell lines K1, SW579, and 8505C and the human thyroid follicular cell line Nthy-ori3-1 were selected and assigned into blank, control vectors, LINC00312 vectors, si-control, and si-LINC00312 groups. Quantitative real-time PCR was used to determine the levels of LINC003121 and Western blotting was used to detect the protein expression of MMP-9, PI3K, t-Akt, and p-Akt. Cell proliferation was assessed by CCK8 assay and EdU incorporation assay, and cell invasion was assessed by Transwell assay. RESULTS The expression of LINC00312 was significantly decreased in TC tissues and cell lines. In an in vitro experiment, si-LINC00312 significantly promoted the invasion and proliferation of TC cells. Conversely, overexpression of LINC00312 decreased cell proliferation and invasion in vitro, and decreased tumorigenicity in TC xenograft models in nude mice. LINC00312-mediated tumor suppression in TC cells may occur via suppression of activation of the PI3K/Akt signaling pathway and expression of MMP-9, and the role of MMP-9 expression induced by overexpressed LINC00312 or si-LINC00312 could be weakened by LY294002 (PI3K inhibitor). CONCLUSIONS LINC00312 can act as a tumor-suppressor in TC by attenuating the PI3K/Akt signaling pathway, and LINC00312 could be a novel diagnosis biomarker and a promising therapeutic target for TC patients.

LncRNA CASC15 promotes colon cancer cell proliferation and metastasis by regulating the miR‑4310/LGR5/Wnt/β‑catenin signaling pathway

Previous studies have indicated that overexpression of long noncoding RNA cancer susceptibility 15 (CASC15) may promote tumor development and progression in gastric cancer and hepatocellular carcinoma. However, the function of CASC15 in colon cancer remains unknown. In the present study, the expression of CASC15 was upregulated in colon cancer tissues and its expression was correlated with clinical Tumor‑Node‑Metastasis stage and tumor metastasis. In addition, knockdown of CASC15 significantly inhibited the proliferation, migration and invasion of colon cancer cells in vitro and in vivo. Following mechanistic experiments, CASC15 was observed to act as a sponge to suppress microRNA (miR)‑4310 that targeted LGR5. Through the inhibition of miR‑4310, CASC15 promoted leucine‑rich repeat‑containing G‑protein coupled receptor 5 (LGR5) expression and consequently activated the Wnt/β‑catenin signaling pathway. The results revealed that the inhibition of the Wnt/β‑catenin signaling pathway in CASC15‑overexpressing colon cancer cells suppressed cellular proliferation, migration and invasion. Collectively, these results demonstrated that CASC15 promoted colon cancer growth and metastasis through the activation of the Wnt/β‑catenin signaling pathway in a miR‑4310/LGR5 dependent manner. Thus, the present study suggested that CASC15 may be a therapeutic target for colon cancer treatment.

LncRNA NR2F1-AS1 regulates hepatocellular carcinoma oxaliplatin resistance by targeting ABCC1 via miR-363

Emerging evidence has validated the vital role of long non‐coding RNA (lncRNA) in the chemoresistance of cancer treatment. In the present study, we investigate the function of lncRNA NR2F1‐AS1 on oxaliplatin (OXA) resistance of hepatocellular carcinoma (HCC) and discover the underlying molecular mechanism. Results revealed that lncRNA NR2F1‐AS1 was up‐regulated in oxaliplatin‐resistant HCC tissue and cells using microarray analysis and RT‐PCR. Meanwhile, ABCC1 protein was overexpressed in OXA‐resistant HCC cells (Huh7/OXA and HepG2/OXA). In vitro, NR2F1‐AS1 knockdown reduced the invasion, migration, drug‐resistant gene (MDR1, MRP5, LRP1) and IC50 value in Huh7/OXA and HepG2/OXA cells. In vivo, NR2F1‐AS1 knockdown decreased the tumour weight of HCC cells. Bioinformatics tools and luciferase reporter assay confirmed miR‐363 targeted the 3′‐UTR of NR2F1‐AS1 and ABCC1 mRNA, presenting that NR2F1‐AS1 promoted ABCC1 expression through endogenous sponging miR‐363. In summary, results conclude that NR2F1‐AS1 regulates HCC OXA resistance through targeting miR‐363‐ABCC1 pathway, providing a vital theoretic mechanism and therapeutic target for HCC chemoresistance.