Long noncoding RNA H19 contributes to gallbladder cancer cell proliferation by modulated miR-194-5p targeting AKT2. Tumour Biol. 2016;37:9721-9730. [PMID: 26803515 DOI: 10.1007/s13277-016-4852-1]

Natural products and long noncoding RNA signatures in gallbladder cancer: a review focuses on pathogenesis, diagnosis, and drug resistance

Gallbladder cancer (GBC) is an aggressive and lethal malignancy with a poor prognosis. Long noncoding RNAs (lncRNAs) and natural products have emerged as key orchestrators of cancer pathogenesis through widespread dysregulation across GBC transcriptomes. Functional studies have revealed that lncRNAs interact with oncoproteins and tumor suppressors to control proliferation, invasion, metastasis, angiogenesis, stemness, and drug resistance. Curcumin, baicalein, oleanolic acid, shikonin, oxymatrine, arctigenin, liensinine, fangchinoline, and dioscin are a few examples of natural compounds that have demonstrated promising anticancer activities against GBC through the regulation of important signaling pathways. The lncRNAs, i.e., SNHG6, Linc00261, GALM, OIP5-AS1, FOXD2-AS1, MINCR, DGCR5, MEG3, GATA6-AS, TUG1, and DILC, are key players in regulating the aforementioned processes. For example, the lncRNAs FOXD2-AS1, DILC, and HOTAIR activate oncogenes such as DNMT1, Wnt/β-catenin, BMI1, and c-Myc, whereas MEG3 and GATA6-AS suppress the tumor proteins NF-κB, EZH2, and miR-421. Clinically, specific lncRNAs can serve as diagnostic or prognostic biomarkers based on overexpression correlating with advanced TNM stage, metastasis, chemoresistance, and poor survival. Therapeutically, targeting aberrant lncRNAs with siRNA or antisense oligos disrupts their oncogenic signaling and inhibits GBC progression. Overall, dysfunctional lncRNA regulatory circuits offer multiple avenues for precision medicine approaches to improve early GBC detection and overcome this deadly cancer. They have the potential to serve as novel biomarkers as they are detectable in bodily fluids and tissues. These findings enhance gallbladder treatments, mitigating resistance to chemo- and radiotherapy.

Panel of serum long non-coding RNAs as potential non-invasive biomarkers for gallbladder carcinoma

Gallbladder carcinoma (GBC) is a common malignancy and is usually diagnosed in the late stages of the disease. The identification of new effective early diagnostic biomarkers could represent an effective approach in reducing mortality in GBC. Altered expression of long non-coding RNAs (lncRNAs) is believed to be associated with the emergence and development of GBC. Our study aims to identify the expression of a range of circulating lncRNAs, including HOTAIR, ANRIL, H19, CCAT1 and MEG3, in matched serum and tissues of GBC for diagnosis and its association with clinicopathological features. The case and control study included matched serum and tissues from 63 GBC, 19 cholecystitis (CC), and 46 normal controls (NC). RNA extraction and cDNA synthesis from serum and fresh tissue match were performed using commercially available kits. Relative expression was assessed using SYBR Green real-time quantitative polymerase chain reaction. Circulating lncRNA levels including HOTAIR, ANRIL and H19 were upregulated in serum samples, while MEG3 and CCAT1 were downregulated in GBC compared to controls. The trend towards upregulation and downregulation was comparable in the tissue. HOTAIR and MEG3 levels were significantly different between serum CC and early-stage GBC (p = 0.0373, 0.0020), while H19 was significantly upregulated comparing early-stage GBC to advanced-stage GBC (p = 0.018). The expression of ANRIL was significant with M stage (p = 0.0488), H19 with stage (p = 0.009), M stage (p=<0.0001) & stage (0.009) and CCAT1 with M stage (0.044). When distinguishing GBC and NC, AUC for HOTAIR was 0.75, ANRIL 0.78, H19 0.74, CCAT1 0.80 and 0.96 for MEG3. The combination sensitivity for lncRNAs ranged from 84.13% (CI: 72.74-92.12%) to 100.0% (CI: 94.31-100.0%). Significant diagnostic value in discriminating pathologic stage was observed for ANRIL and MEG3 (p = 0.022, p = 0.0005). LncRNA show a significant change in expression in GBC and in discrimination of early stage from late-stage disease. The detection of 2 lncRNAs in panels, in coordination with radiology, could represent a potential serum-based biomarker for early-stage GBC diagnosis.

Long non-coding RNA H19: a potential biomarker and therapeutic target in human malignant tumors

Long non-coding RNAs play important roles in cellular functions and disease development. H19, as a long non-coding RNA, is pervasively over-expressed in almost all kinds of human malignant tumors. Although many studies have reported that H19 is closely associated with tumor cell proliferation, apoptosis, invasion, metastasis, and chemoresistance, the role and mechanism of H19 in gene regulation and tumor development are largely unclear. In this review, we summarized the recent progress in the study of the major functions and mechanisms of H19 lncRNA in cancer development and progression. H19 possesses both oncogenic and tumor-suppressing activities, presumably through regulating target gene transcription, mRNA stability and splicing, and competitive inhibition of endogenous RNA degradation. Studies indicate that H19 may involve in cell proliferation and apoptosis, tumor initiation, migration, invasion, metastasis and chemoresistance and may serve as a potential biomarker for early diagnosis, prognosis, and novel molecular target for cancer therapy.

miR-126 regulates the proliferation, migration, invasion, and apoptosis of non-small lung cancer cells via AKT2/HK2 axis

This study tended to clarify the role of miR-126 in non-small cell lung cancer (NSCLC) cell biological behaviors in vitro, containing cell proliferation, migration, invasion, and apoptosis. miRNA expression microarray related to NSCLC was accessed from gene expression omnibus (GEO) database and subjected to differential analysis using the "limma" package. Real-time quantitative PCR was conducted to assess the expression of miR-126 in NSCLC cell lines. wIn vitro experiments including 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), wound healing assay, Transwell, and flow cytometry assay were used for evaluating the effect of miR-126 on cell proliferation, migration, invasion, and apoptosis. Additionally, target mRNA for miR-126 was predicted and further validated by bioinformatics analysis and dual-luciferase reporter assay, respectively. It suggested that miR-126 was significantly down-regulated in NSCLS based on the expression microarray, and similar expression trend was exhibited in cancer cell lines. In the meantime, overexpression of miR-126 was found to result in inhibition of cell proliferation, migration, and invasion while promotion of cell apoptosis, with reductions in protein expression of AKT2 and phosphorylated HK2 (p-HK2) as well. AKT2, identified to be a direct target of miR-126 in NSCLC as judged by dual-luciferase reporter assay. Additionally, overexpression of AKT2 was observed to have the ability of elevating p-HK2 protein expression and reversing the effect of miR-126 on NSCLC cell proliferation, migration, and invasion. Given the above findings, we can see that miR-126 exerts its role in NSCLC cell proliferation, migration, invasion, and apoptosis with the aid of AKT2/HK2 axis.

Non-coding RNAs as potential biomarkers of gallbladder cancer

Gallbladder cancer (GBC) performs strongly invasive and poor prognosis, and adenocarcinoma is the most common histological type in it. Statistically, the 5-year survival rate of patients with advanced GBC is less than 5%. Such dismal outcome might be caused by chemotherapy resistance and native biology of tumor cells, regardless of emerging therapeutic strategies. Early diagnosis, depending on biomarkers, receptors and secretive proteins, is more important than clinical therapy, guiding the pathologic stage of cancer and the choice of medication. Therefore, it is in urgent need to understand the specific pathogenesis of GBC and strive to find promising novel biomarkers for early screening in GBC. Non-coding RNAs (ncRNAs), especially microRNAs (miRNAs, miRs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), are confirmed to participate in and regulate the occurrence and development of GBC. Exceptionally, lncRNAs and circRNAs could act as competing endogenous RNAs (ceRNAs) containing binding sites for miRNAs and crosstalk with miRNAs to target regulatory downstream protein-coding messenger RNAs (mRNAs), thus affecting the expression levels of specific proteins to participate in and regulate the development and progression of GBC. It follows that ncRNAs may become promising biomarkers and potential therapeutic targets for GBC. In this review, we mainly summarize the recent research progress of miRNAs and lncRNAs in regulating the development and progression of GBC, chemoresistance, and predicting the prognosis of patients, and highlight the potential applications of the lncRNA/circRNA-miRNA-mRNA cross-regulatory networks in early diagnosis, chemoresistance, and prognostic evaluation, aiming to better understand the pathogenesis of GBC and develop new diagnostic and therapeutic strategies.

Long non-coding RNA (lncRNA) H19 in human cancer: From proliferation and metastasis to therapy

Initiation and development of cancer depend on multiple factors that mutations in genes and epigenetic level can be considered as important drivers. Epigenetic factors include a large family of members and understanding their function in cancer has been a hot topic. LncRNAs are RNA molecules with no capacity in synthesis of proteins, and they have regulatory functions in cells. LncRNAs are localized in nucleus and cytoplasm, and their abnormal expression is related to development of tumor. This manuscript emphasizes on the role of lncRNA H19 in various cancers and its association with tumor hallmarks. The function of lncRNA H19 in most tumors is oncogenic and therefore, tumor cells increase its expression for promoting their progression. LncRNA H19 contributes to enhancing growth and cell cycle of cancers and by EMT induction, it is able to elevate metastasis rate. Silencing H19 induces apoptotic cell death and disrupts progression of tumors. LncRNA H19 triggers chemo- and radio-resistance in cancer cells. miRNAs are dually upregulated/down-regulated by lncRNA H19 in increasing tumor progression. Anti-cancer agents reduce lncRNA H19 in impairing tumor progression and increasing therapy sensitivity. A number of downstream targets and molecular pathways for lncRNA H19 have been detected in cancers including miRNAs, RUNX1, STAT3, β-catenin, Akt2 and FOXM1. Clinical studies have revealed potential of lncRNA H19 as biomarker and its association with poor prognosis. LncRNA H19 can be transferred to cancer cells via exosomes in enhancing their progression.

Role of lncRNAs in the Development of an Aggressive Phenotype in Gallbladder Cancer

Long non-coding RNAs are sequences longer than 200 nucleotides that are involved in different normal and abnormal biological processes exerting their effect on proliferation and differentiation, among other cell features. Functionally, lncRNAs can regulate gene expression within the cells by acting at transcriptional, post-transcriptional, translational, or post-translational levels. However, in pathological conditions such as cancer, the expression of these molecules is deregulated, becoming elements that can help in the acquisition of tumoral characteristics in the cells that trigger carcinogenesis and cancer progression. Specifically, in gallbladder cancer (GBC), recent publications have shown that lncRNAs participate in the acquisition of an aggressive phenotype in cancer cells, allowing them to acquire increased malignant capacities such as chemotherapy resistance or metastasis, inducing a worse survival in these patients. Furthermore, lncRNAs are useful as prognostic and diagnostic biomarkers since they have been shown to be differentially expressed in tumor tissues and serum of individuals with GBC. Therefore, this review will address different lncRNAs that could be promoting malignant phenotypic characteristics in GBC cells and lncRNAs that may be useful as markers due to their capability to predict a poor prognosis in GBC patients.

LncRNA H19: A novel oncogene in multiple cancers

Long non-coding RNAs (lncRNAs) are a series of non-coding RNAs that lack open reading frameworks. Accumulating evidence suggests important roles for lncRNAs in various diseases, including cancers. Recently, lncRNA H19 (H19) became a research focus due to its ectopic expression in human malignant tumors, where it functioned as an oncogene. Subsequently, H19 was confirmed to be involved in tumorigenesis and malignant progression in many tumors and had been implicated in promoting cell growth, invasion, migration, epithelial-mesenchymal transition, metastasis, and apoptosis. H19 also sequesters some microRNAs, facilitating a multilayer molecular regulatory mechanism. In this review, we summarize the abnormal overexpression of H19 in human cancers, which suggests wide prospects for further research into the diagnosis and treatment of cancers.

Long non-coding RNAs regulating multiple proliferative pathways in cancer cell

Long non-coding RNAs (lncRNAs) belong to an extremely heterogeneous class of non-coding RNAs with a length ranging from 200 to 100,000 bp. They modulate a series of cellular pathways in both physiological and pathological context. It is no coincidence that they are expressed in an aberrant way in pathologies such as cancer, so as to deserve to be subclassified as oncogenes or tumor suppressors. These molecules are also involved in the regulation of cancer cell proliferation. Several lncRNAs are able to modulate cell growth both positively and negatively, and in this review we have focused on a small group of them, characterized by the simultaneous action on different pathways regulating cell proliferation. They have been considered in the light of their behavior in three different subtypes of proliferative pathways that we can define as (I) tumor suppressor, (II) oncogenic and (III) transcriptionally-driven. More specifically, we have characterized some lncRNAs considered oncogenes (such as H19, linc-ROR, MALAT1, HULC, HOTAIR and ANRIL), tumor suppressors (such as MEG3 and lincRNA-p21), and both oncogenes/tumor suppressors (UCA1 and TUG1) in a little more detail. As can be understood from the review, the interactions between lncRNAs and their molecular targets, only in the context of controlling cell proliferation, give rise to an intricate molecular network, the understanding of which, in the future, will certainly be of help for the treatment of molecular diseases such as cancer.

Sulforaphane Inhibits the Expression of Long Noncoding RNA H19 and Its Target APOBEC3G and Thereby Pancreatic Cancer Progression

Pancreatic ductal adenocarcinoma (PDAC) is extremely malignant and the therapeutic options available usually have little impact on survival. Great hope is placed on new therapeutic targets, including long noncoding RNAs (lncRNAs), and on the development of new drugs, based on e.g., broccoli-derived sulforaphane, which meanwhile has shown promise in pilot studies in patients. We examined whether sulforaphane interferes with lncRNA signaling and analyzed five PDAC and two nonmalignant cell lines, patient tissues (n = 30), and online patient data (n = 350). RT-qPCR, Western blotting, MTT, colony formation, transwell and wound healing assays; gene array analysis; bioinformatics; in situ hybridization; immunohistochemistry and xenotransplantation were used. Sulforaphane regulated the expression of all of five examined lncRNAs, but basal expression, biological function and inhibition of H19 were of highest significance. H19 siRNA prevented colony formation, migration, invasion and Smad2 phosphorylation. We identified 103 common sulforaphane- and H19-related target genes and focused to the virus-induced tumor promoter APOBEC3G. APOBEC3G siRNA mimicked the previously observed H19 and sulforaphane effects. In vivo, sulforaphane- or H19 or APOBEC3G siRNAs led to significantly smaller tumor xenografts with reduced expression of Ki67, APOBEC3G and phospho-Smad2. Together, we identified APOBEC3G as H19 target, and both are inhibited by sulforaphane in prevention of PDAC progression.

Long Non-Coding RNA AC118344.1 Promotes Gastric Cancer Cell Proliferation, Invasion, and Metastasis via AKT2 and Its Downstream Molecules HK2 and MMP2

Background

Gastric cancer (GC) is a highly occurring cancer with poor prognosis. Reports indicate that long non-coding RNA (LncRNA) potentially regulates tumor progression. Herein, we aim to explore the effect of LncRNA AC118344.1 on the progression of gastric cancer.

Methods

Overexpression and knockout experiments were used to clarify the potential molecular signaling mechanisms induced by AC118344.1. CCK-8, transwell and in vivo metastasis assay were used to detect the function of AC118344.1 in AGS and SGC-7901 cells. Additionally, shRNA silencing techniques, qRT-PCR and Western blot assay were used to explore the relationship between AC118344.1, AKT2, and its downstream molecules.

Results

Upregulating the expression of AC118344.1 induces cell proliferation, invasion in vitro, and lung metastasis in vivo whereas downregulating the expression of AC118344.1 inhibits these effects. Besides, silencing the expression of AC118344.1 downregulated the expression of AKT2 in both the two cells. On the other hand, silencing the expression of AKT2 by shRNA was unable to downregulate the expression of AC118344.1 in both the gastric cancer cells. Also, AC118344.1 regulated AKT2 via its downstream molecules including HK2 and MMP2.

Conclusion

AC118344.1 promotes gastric cancer cell proliferation and invasion and lung metastasis in nude mice by upregulating the expression of AKT2 and its downstream molecules (HK2 and MMP2). Therefore, our findings provide a novel mechanism of the AC118344.1-AKT2-HK2/MMP2 axis in regulating the development of gastric cancer cells.

miR-194-5p negatively regulates the proliferation and differentiation of rabbit skeletal muscle satellite cells

Skeletal muscle satellite cells (SMSCs), also known as a multipotential stem cell population, play a crucial role during muscle growth and regeneration. In recent years, numerous miRNAs have been associated with the proliferation and differentiation of SMSCs in a number of mammalian species; however, the regulatory mechanisms of miR-194-5p in rabbit SMSCs still remain scarce. In this study, miR-194-5p was first observed to be highly expressed in the rabbit leg muscle. Furthermore, both the mimics and inhibitor of miR-194-5p were used to explore its role in the proliferation and differentiation of rabbit SMSCs cultured in vitro. Results from both EdU and CCK8 assays showed that miR-194-5p inhibited the proliferation of SMSCs. Meanwhile, Mef2c was identified as a target gene of miR-194-5p based on the dual-luciferase reporter assay results. In addition, upregulation of miR-194-5p decreased the expression levels of Mef2c and MyoG during rabbit SMSCs differentiation on Days 3 and 7 of in vitro culture. Taken together, these data demonstrated that miR-194-5p negatively regulates the proliferation and differentiation of rabbit SMSCs by targeting Mef2c.

H19/miR-152-3p/TCF4 axis increases chemosensitivity of gastric cancer cells through suppression of epithelial-mesenchymal transition

BACKGROUND

Adriamycin (ADM) is a drug commonly used for treating gastric cancer (GC). However, chemoresistance presents an obstacle to achieving successful outcomes in patients treated with chemotherapy. This study aimed to explore the effect of long non-coding RNA (lncRNA) H19 on chemoresistance in GC and its potential molecular mechanism.

METHODS

The expression of H19 was detected in GC tissues and cell lines. The interaction between miR-152 with H19 and transcription factor 4 (TCF4) was validated by luciferase reporter assay. CCK-8 and flow cytometry were employed to measure cell viability and apoptosis, respectively. The levels of epithelial-mesenchymal transition (EMT) markers (E-cadherin, N-cadherin, Slug, Snail, and Twist) were detected by Western blot assay. A mouse model was established by subcutaneously injecting MGC-803 cells stably transfected with sh-H19 to investigate the effect of H19/miR-152-3p/TCF4 axis on ADM in vivo.

RESULTS

In vitro, we observed that H19 was overexpressed in GC tissues and cell lines. After knockdown of H19, the IC50 of ADM was decreased and cell apoptosis rates increased in both BGC-823ADM and MGC-803ADM cells. Furthermore, H19 shRNA was found to inhibit epithelial-mesenchymal transition (EMT), and induction of EMT counteracted the inhibitory effect of H19 shRNA on chemoresistance of GC cells. miR-152 was a target of H19, and its expression was downregulated in GC tissues and cell lines. Furthermore, the expression of TCF4 was negatively regulated by miR-152 but positively regulated by H19. In vivo, the data indicated that H19 shRNA enhanced the chemosensitivity of GC tumor cells to ADM through sponging miR-152 from TCF4, resulting in the suppression of EMT.

CONCLUSIONS

The results of this study elucidated that H19 was overexpressed in GC tissues and cell lines, and knockdown of lncRNA H19 increased the chemosensitivity of GC cells to ADM via sponging miR-152 from TCF4. The H19/miR-152/TCF4 axis may provide a new perspective for treating GC.

Long Non-Coding RNAs in Biliary Tract Cancer-An Up-to-Date Review

The term long non-coding RNA (lncRNA) describes non protein-coding transcripts with a length greater than 200 base pairs. The ongoing discovery, characterization and functional categorization of lncRNAs has led to a better understanding of the involvement of lncRNAs in diverse biological and pathological processes including cancer. Aberrant expression of specific lncRNA species was demonstrated in various cancer types and associated with unfavorable clinical characteristics. Recent studies suggest that lncRNAs are also involved in the development and progression of biliary tract cancer, a rare disease with high mortality and limited therapeutic options. In this review, we summarize current findings regarding the manifold roles of lncRNAs in biliary tract cancer and give an overview of the clinical and molecular consequences of aberrant lncRNA expression as well as of underlying regulatory functions of selected lncRNA species in the context of biliary tract cancer.

lncRNA-H19/miR-29a axis affected the viability and apoptosis of keloid fibroblasts through acting upon COL1A1 signaling

This study was intended to clarify the potential of applying the long-chain noncoding RNA H19/miR-29a axis in keloid treatment by elucidating its correlation with the activity of fibroblasts. In this study, 80 keloid tissues, 63 normal fibrous tissues, and 91 normal skin tissues were collected in advance, and concurrently, fibroblasts separated from the tissues were cultured. Besides this, the si-H19, pcDNA3.1-H19, miR-29a mimic, and miR-29a inhibitor were transfected to keloid fibroblasts, whose proliferation, apoptosis, and metastasis were appraised by employing the colony formation assay, flow cytometry, and transwell assay. In addition, the luciferase reporter gene assay was carried out to determine whether targeted regulation was present between H19 and miR-29a, as well as between miR-29a and COL1A1. The study results demonstrated that keloid tissues and fibroblasts exhibited observably upregulated H19 expression and downregulated miR-29a expression, relative to normal skin tissues and fibroblasts (P < .05). Also observed was a negative correlation between H19 expression and miR-29a expression among the gathered keloid tissues (r_s  = -.267, P = .017). Furthermore, in vitro transfection of pcDNA3.1-H19 or miR-29a inhibitor could intensify viability, proliferation, migration, and invasion of the fibroblasts (P < .05), while silencing of H19 and overexpression of miR-29a hindered both metastasis and multiplication of the fibroblasts significantly (P < .05). In addition, H19 was capable of altering miR-29a expression within fibroblasts by directly sponging it, and overexpression of COL1A1 could deter the impact of miR-29a on viability, proliferation, migration, and invasion of fibroblasts (P < .05). In conclusion, H19 might facilitate proliferation and metastasis of fibroblasts by modifying downstream miR-29a and COL1A1, which was expected to allow for development of keloid-targeted treatments.

ZEB1 activated-VPS9D1-AS1 promotes the tumorigenesis and progression of prostate cancer by sponging miR-4739 to upregulate MEF2D

Prostate cancer (PCa) is a destructive malignancy with a bad prognosis. LncRNA VPS9D1-AS1 has recently been delineated as an oncogene in some kinds of tumor, whereas, the function of VPS9D1-AS1 in PCa remains to be clarified. In this study, we researched its underlying role in PCa. The expression of VPS9D1-AS1 was conspicuously upregulated in PCa tissues and cells. And absence of VPS9D1-AS1 inhibited cell proliferation, migration and invasion, and promoted cell apoptosis in PCa. In addition, VPS9D1-AS1 overexpression led to opposite results. Furthermore, VPS9D1-AS1/MEF2D could sponge with miR-4739. VPS9D1-AS1/MEF2D and miR-4739 were inversely correlated in tumor cells. And the expression of miR-4739 is markedly downregulated in PCa, meanwhile, that of MEF2D exhibited the opposite tendency. However, MEF2D was positively regulated by VPS9D1-AS1. Moreover, MEF2D upregulation offset the suppressive effects of VPS9D1-AS1 deficiency on cell proliferation, migration and invasion in PCa. Additionally, ZEB1 contained the binding sites of VPS9D1-AS1 promoter, and there existed positive relation between them. Taken together, above results illustrated that ZEB1 activated-VPS9D1-AS1 promotes the tumorigenesis and progression of PCa by sponging miR-4739 to upregulate MEF2D, which offering a new useful reference for studying the development process of PCa.

H19 lncRNA: Roles in tumorigenesis

H19 is a long non-coding RNA [lncRNA] which was firstly described as an oncofetal transcript. The imprinted gene is normally expressed from the maternal allele. However, this pattern of imprinting is dysregulated in several cancers leading to aberrant up-regulation of H19 in malignant tissues. Several studies have utilized this aberrant expression pattern to find specific biomarkers for detection of cancer in tumoral tissues or peripheral blood. Moreover, single nucleotide polymorphisms within H19 have been associated with risk of oral squamous cell carcinoma, hepatocellular carcinoma, breast cancer, bladder cancer, gastric cancer and colorectal cancer. Taken together, H19 is regarded as a biomarker for cancer and a putative therapeutic target in these human disorders.

LncRNA CR749391 acts as a tumor suppressor to upregulate KLF6 expression via interacting with miR-181a in gastric cancer

Long non-coding RNAs (lncRNAs) are novel regulators for post-transcriptional gene expression, and altered lncRNAs function and expression are associated with tumorigenesis and cancer progression, although the biological functions of most lncRNAs in various cancer types and their underlying regulatory interactions have remained largely elusive. Our previous study identified microRNA (miR)-181a as a regulator of Kruppel-like factor 6 (KLF6). In the present study, a bioinformatical analysis was performed to identify the novel lncRNA CR749391 as a potential regulator of miR-181a that contains four putative binding sites. Subsequent in vitro experiments in gastric cancer (GC) cells demonstrated that CR749391 interacted with miR-181a to regulate KLF6 expression. First, a direct binding interaction was confirmed using luciferase reporter and RNA immunoprecipitation and pull-down assays. In addition, CR749391 was observed to be downregulated in GC compared with that of normal gastric cell lines. A functional study also revealed that CR749391 depletion in normal gastric epithelial cells promoted cell viability, migration and invasion, and conferred resistance to apoptosis, whereas ectopic CR749391 overexpression had the opposite effect in GC cells and inhibited in vivo tumor growth. In addition, CR749391 was observed to be downregulated in GC compared with that of normal gastric tissues, which was associated with KLF6 but inversely associated with miR-181a levels. Overall, the CR749391/miR-181a regulatory interaction and association between CR749391 and KLF6 may enhance the current understanding of GC pathogenesis, although CR749391 association with GC prognosis needs further study. The current study could provide a novel approach for lncRNA-mediated targeted GC therapy.

LINC00703 Acts as a Tumor Suppressor via Regulating miR-181a/KLF6 Axis in Gastric Cancer

Purpose

Long noncoding RNA 00703 (LINC00703) was found originating from a region downstream of Kruppel-like factor 6 (KLF6) gene, having 2 binding sites for miR-181a. Since KLF6 has been reported as a target of miR-181a in gastric cancer (GC), this study aims to investigate whether LINC00703 regulates the miR-181a/KLF6 axis and plays a functional role in GC pathogenesis.

Materials and Methods

GC tissues, cell lines, and nude mice were included in this study. RNA binding protein immunoprecipitation (RIP) and pull-down assays were used to evaluate interaction between LINC00703 and miR-181a. Quantitative real-time polymerase chain reaction and western blot were applied for analysis of gene expression at the transcriptional and protein levels. A nude xenograft mouse model was used to determine LINC00703 function in vivo.

Results

We revealed that LINC00703 competitively interacts with miR-181a to regulate KLF6. Overexpression of LINC00703 inhibited cell proliferation, migration/invasion, but promoted apoptosis in vitro, and arrested tumor growth in vivo. LINC00703 expression was found to be decreased in GC tissues, which was positively correlated with KLF6, but negatively with the miR-181a levels.

Conclusions

LINC00703 may have an anti-cancer function via modulation of the miR-181a/KLF6 axis. This study also provides a new potential diagnostic marker and therapeutic target for GC treatment.

Long Noncoding RNA NEAT1 Promotes Cell Proliferation And Invasion And Suppresses Apoptosis In Hepatocellular Carcinoma By Regulating miRNA-22-3p/akt2 In Vitro And In Vivo

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most aggressive cancers that is associated with cirrhosis and other chronic liver diseases. Although remarkable progress has been made in past decades, it is still necessary to continue exploring the pathology and development of HCC.

OBJECTIVE

In this study, we elucidated the effect of long noncoding RNA (lncRNA) NEAT1 on HCC development and underlying mechanisms.

METHODS

Clinicopathological features of HCC patients were collected and the correlations with NEAT1 expression were assessed. To determine cell activities, CCK-8, flow cytometry, invasion assays, and TUNEL assays were performed. Real-time PCR, Western blot, and luciferase reporter assays were performed to investigate the related mechanism of HCC.

RESULTS

The results revealed that NEAT1 expression was associated with tumor size and differentiation where NEAT1 was upregulated in both HCC tissues and cell lines. Overexpression of NEAT1 promoted proliferation and invasion while inhibited apoptosis in HCC cells, which was opposite to the effect of NEAT1 knockdown. Also, AKT2 was increased in HCC tissues. Downregulation of AKT2 was associated with reduced cell proliferation and invasion while increased apoptosis, while overexpression of AKT2 exerted opposite roles. In addition, the expression of miRNA-22-3p displayed an inverse association with NEAT1. miRNA-22-3p mimic and inhibitor suppressed and promoted HCC development, respectively. The luciferase assay revealed that both NEAT1 and AKT2 were direct target genes of miRNA-22-3p. Furthermore, knockdown and overexpression of NEAT1 suppressed and promoted tumor growth in the HCC mouse model, which were abolished by the miRNA-22-3p inhibitor and mimic, respectively.

CONCLUSION

In conclusion, the results demonstrate that NEAT1 promotes the development of HCC, both in vitro and in vivo, through regulating miRNA-22-3p/AKT2, and provides insight into developing a new strategy for HCC treatment.

[Effect of long chain non-coding RNA H19 on the migration and invasion of oral cancer cells and its molecular mechanism]

OBJECTIVE

To investigate the effect of the long chain non-coding RNA H19 (lncRNA H19) on the invasion and migration of oral cancer cells and its related molecular mechanism.

METHODS

The expression levels of lncRNA H19, miR-107, and cyclin-dependent kinase 6 (CDK6) in the immortalized oral epithelial cell line HIOEC and the oral cancer cell line CAL27 were detected by real-time quantitative polymerase chain reaction. CAL27 cells were transfected with siRNA H19, miR-107 mimics, pcDNA H19, or anti-miR-107, and the effects of H19 and miR-107 on the invasion and migration of cells were examined via Transwell assay. The TargetScan database predicted the targeting of H19, miR-107, and CDK6. Double luciferase reporter gene assay was performed to detect interactions among H19, miR-107, and CDK6. Western blot analysis was conducted to examine the effects of H19 and miR-107 on the protein level of the target gene CDK6.

RESULTS

Compared with that in HIOEC cells, the expression of H19 was significantly increased in CAL27 cells (P<0.05). After transfection with siRNA H19, the expression of H19 decreased, and the invasion and migration ability of CAL27 cells were inhibited (P<0.05). H19 could bind specifically to the 3'-UTR of miR-107 to modulate the expression of miR-107. Compared with that in HIOEC cells, the expression of miR-107 significantly decreased in CAL27 cells (P<0.05). The expression of miR-107 increased after transfection with siRNA H19, and anti-mir-107 co-transfection could promote the invasion and migration ability of siRNA H19 in CAL27 cells (P<0.05). Compared with that in HIOEC cells, CDK6 expression significantly increased in CAL27 cells (P<0.05), and the expression level of the gene was coregulated by H19 and miR-107 (P<0.05).

CONCLUSIONS

lncRNA H19 plays an important role in the development of oral cancer. It can regulate the invasion and migration of oral cancer cells by targeting the miR-107/CDK6 signaling axis.

Circular RNA USP1 regulates the permeability of blood-tumour barrier via miR-194-5p/FLI1 axis

Recent studies indicate circular RNAs are related to dysregulation of vascular endothelial cell function, yet the underlying mechanisms have remained elusive. Here, we characterized the functional role of circular RNA USP1 (circ‐USP1) in the regulation of the blood‐tumour barrier (BTB) permeability and the potential mechanisms. In the current study, the circ‐USP1 expressing level was up‐regulated in glioma cerebral microvascular endothelial cells (GECs) of the BTB model in vitro. Knockdown of circ‐USP1 disrupted the barrier integrity, increased its permeability as well as reduced tight junction‐related protein claudin‐5, occludin and ZO‐1 expressions in GECs. Bioinformatic prediction and luciferase assay indicated that circ‐USP1 bound to miR‐194‐5p and suppressed its activity. MiR‐194‐5p contributed to circ‐USP1 knockdown‐induced increase of BTB permeability via targeting and down‐regulating transcription factor FLI1. Furthermore, FLI1 regulated the expressions of claudin‐5, occludin and ZO‐1 in GECs through binding to their promoter regions. Single or combined treatment of circ‐USP1 and miR‐194‐5p effectively promoted anti‐tumour drug doxorubicin across BTB to induce apoptosis of glioma cells. Overall, this present study identified the crucial regulation of circ‐USP1 on BTB permeability via miR‐194‐5p/FLI1 axis‐mediated regulation of tight junction proteins, which might facilitate the development of therapeutics against human gliomas.

Roles of MYC-targeting long non-coding RNA MINCR in cell cycle regulation and apoptosis in non-small cell lung Cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) is one of the leading causes of cancer death in the world, and has a relatively low survival rate. Long non-coding RNAs (lncRNAs) have been demonstrated to modulate cancer progression through a variety of molecular mechanisms. We sought to investigate the role and potential mechanism of MYC-induced long non-coding RNA (MINCR) in NSCLC.

METHODS

Expression levels of MINCR was first identified using The Cancer Genome Atlas (TCGA), further confirmed with specimens from 29 NSCLC patients and three cell lines using qRT-PCR. Overexpression and knockdown of MINCR were performed in NSCLC cell lines through MINCR overexpression vectors and synthesized siRNAs, respectively. The roles of MINCR in NSCLC cell lines, such as cell proliferation, cell cycle arrest, and apoptosis, were identified by MTT, flow cytometry, and Western blot. The modulation of MINCR-regulated genes, including c-Myc and its downstream effectors, as well as apoptosis-associated genes, was analyzed using Western blot.

RESULTS

MINCR expression was increased in NSCLC patients from TCGA datasets, and was also significantly increased in our collected specimens from NSCLC patients and NSCLC cell lines. Knocking down of MINCR greatly inhibited the growth of NSCLC cell lines PC9 and A549. In addition, silencing of MINCR induced cell cycle arrest and apoptosis. Furthermore, silencing of MINCR reduced the expression levels of oncogene c-Myc and its downstream cyclin A, cyclin D, CD4, and CDK2, as well as apoptosis-associated Bcl-2, while significantly increased the expression levels of cleaved PARP-1. In the meantime, overexpression of MINCR remarkably enhanced cell proliferation of PC9 cells and activated c-Myc and its downstream effectors.

CONCLUSION

MINCR exerted inhibitory effects on the cell cycle arrest and apoptosis of NSCLC cells by activating c-Myc and its downstream effectors, suggesting that this lncRNA could be used as a potential therapeutic target for the treatment of NSCLC.

MicroRNA-194 inactivates hepatic stellate cells and alleviates liver fibrosis by inhibiting AKT2

BACKGROUND

Activation of hepatic stellate cells (HSCs) is a pivotal event in the onset and progression of liver fibrosis. Loss of microRNA-194 (miR-194) has been reported in activated HSCs, but the actual role of miR-194 in liver fibrosis remains uncertain.

AIM

To explore the role and potential mechanism of miR-194-mediated regulation of liver fibrosis in vitro and in vivo.

METHODS

The expression of miR-194 was examined in human fibrotic liver tissues, activated HSCs, and a carbon tetrachloride (CCl₄) mouse model by qPCR. The effects of AKT2 regulation by miR-194 on the activation and proliferation of HSCs were assessed in vitro. For in vivo experiments, we reintroduced miR-194 in mice using a miR-194 agomir to investigate the functions of miR-194 in liver fibrosis.

RESULTS

MiR-194 expression was notably lacking in activated HSCs from both humans and mice. Overexpression of miR-194 (OV-miR-194) inhibited α-smooth muscle actin (α-SMA) and type I collagen (Col I) expression and suppressed cell proliferation in HSCs by causing cell cycle arrest in G0/G1 phase. AKT2 was predicted to be a target of miR-194. Notably, the effects of miR-194 knockdown in HSCs were almost blocked by AKT2 deletion, indicating that miR-194 plays a role in HSCs via regulation of AKT2. Finally, miR-194 agomir treatment dramatically ameliorated liver fibrosis in CCl₄-treated mice.

CONCLUSION

We revealed that miR-194 plays a protective role by inhibiting the activation and proliferation of HSCs via AKT2 suppression. Our results further propose miR-194 as a potential therapeutic target for liver fibrosis.

Long non-coding RNA H19 knockdown inhibits the cell viability and promotes apoptosis of thyroid cancer cells through regulating the PI3K/AKT pathway

Certain long non-coding (lnc)RNAs have been reported to serve important roles in the genesis and progression of thyroid cancer (TC). Recent studies have demonstrated that the expression of lncRNA H19 is upregulated in TC tissues; however, knowledge of the associated molecular mechanisms is limited. Therefore, the present study aimed to clarify the roles of H19 in TC. The mRNA expression of lncRNA H19 in TC tissues was determined using reverse transcription-quantitative polymerase chain reaction analysis, and the effects of H19 knockdown on cell viability and apoptosis in vitro were assessed using MTT and flow cytometric assays, respectively. Finally, the signaling pathways involved in the effects of H19 were examined. The results indicated that H19 was upregulated in TC tissues. Silencing of H19 inhibited the cell viability and promoted apoptosis of FTC-133 and TPC-1 TC cells, accompanied by an increased expression of B-cell lymphoma 2 (Bcl-2)-associated X protein and caspase 3, and repressed expression of Bcl-2. The results of western blot analysis suggested that the levels of phosphorylated phosphoinositide-3 kinase (PI3K) and phosphorylated AKT were attenuated by H19 silencing. These results suggest that lncRNA H19 exerts an oncogenic function in TC, in part through the PI3K/AKT pathway.

Long noncoding RNAs as potential biomarkers and therapeutic targets in gallbladder cancer: a systematic review and meta-analysis

Background

Mounting evidence has shown that long noncoding RNAs (lncRNAs) can play a substantial role in gallbladder cancer (GBC) development as tumor promotors or suppressors, and their abnormal expression is relevant to GBC patient outcomes. We completed this systematic review and meta-analysis to explore the clinical significance and mechanisms of lncRNAs in GBC.

Methods

We conducted a comprehensive literature search and selected eligible records according to the inclusion and exclusion criteria. Hazard ratios (HRs) and odds ratios (ORs) were extracted or calculated to estimate the relationships of high lncRNA expression with GBC patient survival and clinical outcomes.

Results

Eighteen studies were identified as eligible for this systematic review and meta-analysis. Heterogeneity among HRs of overall survival (OS) was notably high (I² = 86.2%, p < 0.001). Subgroup analysis suggested that overexpression of lncRNAs in a group that is upregulated in GBC showed a significant association with poor OS (HR = 2.454, 95% CI 2.004–3.004, I² = 0%). Conversely, overexpression of lncRNAs in a downregulated group was markedly related to good OS (HR = 0.371, 95% CI 0.267–0.517, I² = 0%). High expression levels of lncRNA AFAP1-AS1, MALAT1 and ROR were positively correlated with tumor size. Expression of lncRNA LET, LINC00152 and HEGBC exhibited a positive correlation with high T status. LncRNA LINC00152, HEGBC, MALAT1 and ROR showed a marked correlation with positive lymph node metastasis (LNM), while lncRNA GCASPC, MEG3, LET and UCA1 had the opposite effect. High expression levels of lncRNA HEGBC, PAGBC, PVT1 and UCA1 predicted high tumor node metastasis (TNM) stages, while lncRNA LET, GCASPC and MEG3 indicated low TNM stages. We also summarized the mechanisms of lncRNAs in GBC.

Conclusion

Aberrant expression of several lncRNAs was indicative of the prognosis of GBC patients, and lncRNAs showed promise as biomarkers and therapeutic targets for GBC.

Knockdown of hsa_circ_0023028 inhibits cell proliferation, migration, and invasion in laryngeal cancer by sponging miR-194-5p

Emerging evidences have proposed that circular RNAs (circRNAs) play a major role in carcinogenesis. Hsa_circ_0023028 has been reported to be aberrantly expressed in laryngeal cancer (LCa). However, the role and the mechanism of hsa_circ_0023028 in LCa have not been adequately studied. In the present study, we demonstrated that hsa_circ_0023028 expression was up-regulated in LCa tissues and cell lines. miR-194-5p was down-regulated in LCa cells. Functionally, knockdown of hsa_circ_0023028 inhibited the proliferation, migration, and invasion of LCa cells, as evidenced by the reduced number of 5-Ethynyl-2'-deoxyuridine (EdU)-positive cells and decreased number of migrated and invaded cells. Additionally, hsa_circ_0023028 was identified as an miR-194-5p sink. A negative correlation between miR-194-5p and hsa_circ_0023028 expression was observed in LCa tissues. Besides, down-regulation of miR-194-5p attenuated the inhibitory effects of hsa_circ_0023028 silencing on LCa cell proliferation, migration, and invasion. In summary, hsa_circ_0023028 functions as an miR-194-5p sponge to promote the proliferation, migration, and invasion of LCa cells.

Long noncoding RNA MALAT1 potentiates growth and inhibits senescence by antagonizing ABI3BP in gallbladder cancer cells

Background

Gallbladder cancer (GBC) is the most malignant cancer occurring in the biliary tract cancer featured with undesirable prognosis, in which most patients die within a year of cholecystectomy. Long noncoding RNAs (lncRNAs) function as critical regulators of multiple stages of cancers. Herein, the mechanism of lncRNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in GBC is investigated.

Methods

Microarray-based analysis initially provided data suggesting that the expression of MALAT1 was up-regulated while that of the ABI family member 3 binding protein (ABI3BP) was down-regulated in GBC tissues and cell lines. Kaplan-Meier method was then adopted to analyze the relationship between the MALAT1 expression and overall survival and disease-free survival of patients with GBC. A set of in vitro and in vivo experiments were conducted by transducing ABI3BP-vector or sh-MALAT1 into GBC cells.

Results

The results confirmed that the cancer prevention effects triggered by restored ABI3BP and depleted MALAT1 as evidenced by suppressed cell growth and enhanced cell senescence. MALAT1 was observed to down-regulate ABI3BP expression through recruitment of the enhancer of zeste homolog 2 (EZH2) to the ABI3BP promoter region while the silencing of MALAT1 or suppression of H3K27 methylation was observed to promote the expression of ABI3BP. Furthermore, GBC patients with high expression of MALAT1 indicated poor prognosis.

Conclusion

The current study clarifies that MALAT1 silencing and ABI3BP elevation impede the GBC development through the H3K27 methylation suppression induced by EZH2, highlighting a promising competitive paradigm for therapeutic approaches of GBC.

Akt in cancer: Mediator and more

Akt is a serine/threonine kinase and it participates in the key role of the PI3K signaling pathway. The Akt can be activated by a wide range of growth signals and the biochemical mechanisms leading to Akt activation are well defined. Once activated, Akt modulates the function of many downstream proteins involved in cellular survival, proliferation, migration, metabolism, and angiogenesis. The Akt is a central node of many signaling pathways and it is frequently deregulated in many types of human cancers. In this review, we provide an overview of Akt function and its role in the hallmarks of human cancer. We also discussed various mechanisms of Akt dysregulation in cancers, including epigenetic modifications like methylation, post-transcriptional non-coding RNAs-mediated regulation, and the overexpression and mutation.

Knockdown of Long Noncoding RNA H19 Represses the Progress of Pulmonary Fibrosis through the Transforming Growth Factor β/Smad3 Pathway by Regulating MicroRNA 140

Long noncoding RNAs (lncRNAs) are involved in various human diseases. Recently, H19 was reported to be upregulated in fibrotic rat lung and play a stimulative role in bleomycin (BLM)-induced pulmonary fibrosis in mice. However, its expression in human fibrotic lung tissues and mechanism of action remain unclear. Here, our observations showed that H19 expression was significantly upregulated and that of microRNA 140 (miR-140) was markedly reduced in pulmonary fibrotic tissues from idiopathic pulmonary fibrosis (IPF) patients and transforming growth factor β1 (TGF-β1)-induced HBE and A549 cells. Moreover, the expression of H19 was negatively correlated with the expression of miR-140 in IPF tissues. H19 knockdown attenuated TGF-β1-induced pulmonary fibrosis in vitro Furthermore, animal experiments showed that H19 knockdown attenuated BLM-induced pulmonary fibrosis in mice. The study of molecular mechanisms showed that H19 functioned via reduction of miR-140 expression by binding to miR-140. The increase of miR-140 inhibited TGF-β1-induced pulmonary fibrosis, and H19 upregulation diminished the inhibitory effects of miR-140 on TGF-β1-induced pulmonary fibrosis, which was involved in the TGF-β/Smad3 pathway. Taken together, our findings showed that H19 knockdown attenuated pulmonary fibrosis via the regulatory network of lncRNA H19-miR-140-TGF-β/Smad3 signaling, and H19 and miR-140 might represent therapeutic targets and early diagnostic and prognostic biomarkers for patients with pulmonary fibrosis.

miR-194 suppresses high glucose-induced non-small cell lung cancer cell progression by targeting NFAT5

Background

Diabetes mellitus (DM) is linked to an increased risk of lung cancer; however, the exact molecular basis is unclear.

Methods

We used a microarray method and found a group of microRNAs differently expressed in lung cancer cells at high or low glucose treatment.

Results

Among these, miR‐194 changed significantly, which indicated further analysis. miR‐194 was significantly downregulated in non‐small cell lung cancer (NSCLC) cells cultured in high glucose (HG) medium and clinical NSCLC tissues with DM. The introduction of miR‐194 significantly suppressed the proliferation, migration, and invasion of lung cancer cells induced by HG, suggesting that miR‐194 may be a suppressor during HG‐induced NSCLC progression. Further analysis indicated that NFAT5 was a direct target gene of miR‐194, evidenced by the direct binding of miR‐194 with the 3’untranslated region of NFAT5. MiR‐194 could decrease the expression of NFAT5 at both messenger RNA and protein levels, while overexpression of NFAT5 reversed the decreased proliferation, migration, and invasion ability mediated by miR‐194 in lung cancer cells.

Conclusion

Our findings provide new insight into the mechanism of NSCLC progression. Therapeutically, miR‐194 may serve as a potential target for the treatment of lung cancer patients with DM.

Tetraspanin 1 promotes epithelial-to-mesenchymal transition and metastasis of cholangiocarcinoma via PI3K/AKT signaling

BACKGROUND

Numerous studies have demonstrated that tetraspanin 1 (TSPAN1), a transmembrane protein, functions as an oncoprotein in many cancer types. However, its role and underlying molecular mechanism in cholangiocarcinoma (CCA) progression remain unclear.

METHODS

In the present study, the expression of TSPAN1 in human CCA and adjacent nontumor tissues was examined using real-time PCR, western blot and immunohistochemistry. The effect of TSPAN1 on proliferation and metastasis was evaluated by functional assays both in vitro and in vivo. A luciferase reporter assay was performed to investigate the interaction between microRNA-194-5p (miR-194-5p) and TSPAN1 3'-untranslated region. Co-immunoprecipitation (co-IP) was used to confirm the interaction between TSPAN1 protein and integrin α6β1 and western blot was used to explore TSPAN1 mechanism.

RESULTS

We found that TSPAN1 was frequently upregulated in CCA and high levels of TSPAN1 correlated with TNM stage, especially metastasis in CCA. TSPAN1 overexpression promoted CCA growth, metastasis, and induced epithelial-to-mesenchymal transition (EMT), while its silencing had the opposite effect both in vitro and in vivo. To explore the differential expression of TSPAN1, we screened miR-194-5p as the upstream regulator of TSPAN1. A combination of high-level TSPAN1 and low-level miR-194-5p predicted poor prognosis in patients with CCA. Furthermore, in accordance with the functional characteristics of the TSPAN superfamily, we proved that TSPAN1 interacted with integrin α6β1 to amplify the phosphoinositide-3-kinase (PI3K)/AKT/glycogen synthase kinase (GSK)-3β/Snail family transcriptional repressor (Snail)/phosphatase and tensin homolog (PTEN) feedback loop.

CONCLUSION

The results indicate that TSPAN1 could be a potential therapeutic target for CCA.

LncRNA H19/miR-194/PFTK1 axis modulates the cell proliferation and migration of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) remains a huge challenge due to its high mortality and morbidity; gene therapy might be a promising treatment for PDAC. The critical role of Wnt-signaling pathway in cancer pathogenesis has been widely recognized; cyclin-dependent kinase 14 (CDK14, PFTK1)-induced low-density lipoprotein receptor-related proteins 5/6 (LRP5/6) phosphorylation is an important issue in Wnt-signaling activation. Long noncoding RNA (LncRNA)-microRNA (miRNA)-messenger RNA (mRNA) modulating the pathogenesis of cancers has been regarded as a major mechanism. In the current study, upregulated lncRNAs positively correlated with PFTK1 were analyzed and selected using The Cancer Genome Atlas (TCGA) database. Of them, lncRNA H19 can activate Wnt signaling in cancers. In PDAC tissues, the expression of H19 and PFTK1 were upregulated; H19 knockdown suppressed the cell proliferation and migration of PDAC, while PFTK1 overexpression partially attenuated the suppressive effect of H19 knockdown. As analyzed by TCGA and predicted by online tools, miR-194 was negatively correlated with PFTK1 and might bind to both H19 and PFTK1, which was further confirmed by luciferase reporter and RNA immunoprecipitation assays. Moreover, the effect of H19 knockdown on PFTK1 protein and the cell proliferation and migration could be partially reversed by miR-194 inhibition; H19/miR-194 axis modulated PDAC cell proliferation and migration through PFTK1 downstream Wnt signaling. Results suggested that rescuing miR-194 expression in PDAC can inhibit lncRNA H19 and PFTK1 expression, subsequently suppressing PDAC cell proliferation and migration. Due to the complexity of the lncRNA-miRNA-mRNA network, further in vivo experiments examining potential side effects are needed in future study to explore the clinical application of these findings.

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.

Long non-coding RNA CRNDE promotes the proliferation, migration and invasion of hepatocellular carcinoma cells through miR-217/MAPK1 axis

Hepatocellular carcinoma (HCC) is an invasive malignant tumour and the second major cause of cancer‐related deaths over the world. CRNDE and miR‐217 are non‐coding RNAs which play critical roles in cell growth, proliferation, migration. Mitogen‐activated protein kinase 1 (MAPK1) also participates in cancer cell process. Hence, this study aimed at investigating the effect of CRNDE on migration and invasion of HCC and figuring out the role of miR‐217 and MAPK1 in this process. The overexpression of CRNDE was demonstrated by a microarray‐based lncRNA profiling study. CRNDE expression in HCC was verified by qRT‐PCR. MTT assay and BrdU staining were applied to detect cell proliferation level. Transwell assay was utilized to examine cell migration and invasiveness abilities. Wound healing assay was performed for further exploration of cell migration capacity. MiR‐217 was predicted by bioinformatics. The dual luciferase reporter assay was performed to corroborate the targeting relationship between CRNDE, miR‐217 and MAPK1. MAPK1, the downstream target of miR‐217, was predicted using bioinformatics and was further confirmed by qRT‐PCR and Western blot. The interaction between CRNDE, miR‐217 and MAPK1 was studied by qRT‐PCR, Western blot, MTT, BrdU, transwell assay and wound healing assay. CRNDE was up‐regulated in HCC tissues and HCC cell lines. The high expression of CRNDE facilitated cell proliferation, migration and invasion, while the inhibited one affected on the contrary. MiR‐217, negatively correlated with CRNDE expression, was the target of CRNDE and was more lowly expressed in HCC. With the high expression of miR‐217, HCC cell proliferation, migration and invasion were suppressed. MAPK1, the possible target of miR‐217, was negatively correlated with miR‐217 but positively correlated with CRNDE and had the same effect in HCC formation process as CRNDE. Long non‐coding RNA CRNDE promotes the proliferation, migration and invasion of HCC cells through miR‐217/MAPK1 axis.

The SOX2OT/miR-194-5p axis regulates cell proliferation and mobility of gastric cancer through suppressing epithelial-mesenchymal transition

Recent studies reported that long noncoding RNAs (LncRNAs) were involved in tumorigenesis of various human cancer types, including gastric cancer (GC) through targeting microRNAs (miRNAs/miRs). The present study investigated the biological functions of LncRNA SOX2 overlapping transcript (SOX2OT)/miR-194-5p axis and its underlying mechanism in the tumor progression of GC. The results showed that relative expression of LncRNA SOX2OT was highly upregulated while the expression of miR-194-5p was down-regulated in GC tissues and cell lines (MGC-803, SGC-7901, MKN-74). Knockdown of SOX2OT inhibited cell proliferation, invasion and migration of GC cells (MGC803, MKN-74) through reducing epithelial-mesenchymal transition (EMT). Moreover, miR-194-5p was predicted to be one of the targets of SOX2OT through bioinformatics analysis and was verified by luciferase reporter assay. miR-194-5p expression was negatively regulated by SOX2OT expression in GC cells and miR-194-5p inhibitor was found to counteract the inhibitory effects of SOX2OT short hairpin (sh)RNA on cell proliferation and mobility through enhancing EMT in GC cells. Taken together, the in vitro experiments revealed that knockdown of SOX2OT inhibited cell proliferation and mobility through suppressing EMT via targeting miR-194-5p in GC. In addition, results from in vivo experiments showed that knockdown of SOX2OT suppressed GC tumor growth and matrix metalloproteinase (MMP)-2 and MMP-9 expression through inhibiting EMT. Besides that, relative expression of miR-194-5p was increased in sh-SOX2OT group compared with sh-NC group. In summary, our study elucidated that the SOX2OT/miR-194-5p axis participated in the tumor progression of GC through regulation of EMT both in vitro and in vivo. Hence, targeting the SOX2OT/miR-194-5p axis may aid in establishing novel strategies for therapy of GC.

Emerging role of lncRNAs in the normal and diseased intestinal barrier

OBJECTIVE

A significant effort has been made to understand the intestinal barrier, but the effective means to prevent, reduce, and restore intestinal mucosal damage remains unclear. Recently, a few of studies have explained the mechanism of the intestinal barrier in long noncoding RNAs (lncRNAs). This review aims to summarize recent views on the function of lncRNAs in the intestinal barrier and discuss the emerging role of lncRNAs in intestinal barrier diseases caused by inflammatory diseases.

METHODS

Observations led us to believe that lncRNAs participate in inflammatory responses, cell proliferation, and control microbial susceptibility. In view of these, lncRNAs have been proved to involve in the intestinal barrier.

RESULTS

lncRNAs directly or indirectly affect TJ mRNA translation and intestinal epithelial cells (IECs) paracellular permeability, as well as IECs proliferation and susceptibility to apoptosis, to modulate the function of the intestinal barrier. miRNAs play a pivotal role in this process.

CONCLUSIONS

lncRNAs have been shown to be fundamentally involved in intestinal mucosal regeneration, protection, and epithelial barrier function. It may emerge as new and potential factors to be evaluated in the intestinal barrier diseases caused by acute pancreatitis, inflammatory bowel diseases, and imbalance of intestinal flora.

LncRNA HOXA-AS2 and its molecular mechanisms in human cancer

Long non-coding RNAs (lncRNAs), a novel class of noncoding RNAs, are commonly defined as RNA molecules more than 200 nucleotides in length. Emerging research indicated that lncRNA played a vital role in human tumorigenesis and progression by serving as tumor oncogenes or suppressors. LncRNA has been shown to get involved in participate various biological processes, such as cell growth, anti-apoptosis, migration and invasion. LncRNA HOXA cluster antisense RNA2 (HOXA-AS2) is a novel cancer-related lncRNA. It was recently found to exhibit aberrant expression in a variety of malignancies, including breast cancer, gastric cancer, gallbladder carcinoma, hepatocellular carcinoma and pancreatic cancer. The oncogenicity of lncRNA HOXA-AS2 mainly inhibits or promotes the expression of related genes through direct or indirect pathways, suggesting that HOXA-AS2 likely represents a feasible biomarker or therapeutic target in human cancers. In this review, we summarize current evidences concerning the biological functions and mechanisms of HOXA-AS2 during tumor development.

The LncRNA H19/miR-193a-3p axis modifies the radio-resistance and chemotherapeutic tolerance of hepatocellular carcinoma cells by targeting PSEN1

This study was designated to verify if the lncRNA H19/miR-193a-3p axis would play a regulatory role in the radio-/chemo-resistances of HCC cells through targeting PSEN1. Within the study, five human HCC cell lines were prepared, including Bel-7402, HepG2, Hep3b, QGY-7703, and SMMC-7721. Moreover, docetaxel (DT), paclitaxel (Pt), vinorelbine (Vb), and 5-fluorouracil (5-Fu) were managed as the chemo-therapeutics, and single-dose X-rays were performed as radio-therapies. Besides, lncRNA H19 and miR-193a-3p were detected by qRT-PCR and Western blot were implemented to quantify the expressional levels of PSEN1, Ku80, γ-H2AX, and RAD51. Luciferase reporter gene assay was advanced to verify the targeted relationship between lncRNA H19 and miR-193a-3p. As a consequence, QGY-7703 and Bel-7402 were, respectively, the most radiation-sensitive and radiation-proof cell lines, and Bel-7402 was associated with the highest resistances to DT, Pt, Vb, and 5-FU. The restrained lncRNA H19 and over-expressed miR-193a-3p expressions tended to significantly elevate the survival rate and proliferation of Bel-7402 cells, when they were exposed to radiation and subject to chemo-therapies. The lncRNA H19 was also found to directly target miR-193a-3p in inducing the HCC development. PSEN1 appeared to be subject to the modification of lncRNA H19 and miR-193a-3p in its acting on the survival rates and proliferative abilities of HCC cells. The lncRNA H19/miR-193a-3p/PSEN1 axis could be regarded as the treatment targets for HCC, so as to further improve the treatment efficacy of chemo- and radio-therapies for HCC.

Long non-coding RNAs: crucial regulators of gastrointestinal cancer cell proliferation

Studies of long non-coding RNAs (lncRNAs) have been prevalent in the field of non-coding RNA regulation in recent years. LncRNAs exert crucial effects on malignant cell processes in the gastrointestinal system, including proliferation. Aberrant lncRNA expression, through both oncogenes and tumor suppressor genes, is instrumental to tumor cell proliferation. Here, we summarize the different molecular mechanisms and relevant signaling pathways through which multifarious lncRNAs regulate cell proliferation and we show that lncRNAs are potential biomarkers for gastrointestinal cancers.

Effect of CLIC1 gene silencing on proliferation, migration, invasion and apoptosis of human gallbladder cancer cells

This study aimed to explore the effects of CLIC1 gene silencing on proliferation, migration, invasion and apoptosis of human gallbladder cancer (GBC). GBC and normal gallbladder tissues were extracted for the detection of mRNA and protein expressions of CLIC1. GBC‐SD and NOZ cells in the logarithmic growth phase were selected to conduct the experiment. Three different siRNA recombined expression vectors were established using CLIC1 as a target at different sites. Reverse transcription quantitative polymerase chain reaction (RT‐qPCR) and Western blotting were, respectively, used to detect the CLIC1 mRNA and protein expressions. MTT assay was performed to detect the cell proliferation. Flow cytometry was applied to measure the cell apoptosis and cell cycle distribution. The variations of cell migration and invasion were evaluated using Transwell assay. GBC tissues showed higher CLIC1 mRNA and protein expressions than normal gallbladder tissues. The CLIC1 mRNA and protein expressions in the CLIC1 siRNA group were significantly lower than those in the NC and blank groups. Compared with the NC and blank groups, the CLIC1 siRNA group showed a significant decrease in cell proliferation but an obvious increase in apoptosis rate in GBC cells. Besides, in the CLIC1 siRNA group, cell percentage in G0/G1 and G2/M phase was gradually increased but decreased in S phases. The migration and invasion abilities in GBC cells were significantly lower than those in the NC and blank groups. Our study demonstrates that CLIC1 gene silencing could promote apoptosis and inhibit proliferation migration and invasion of GBC cells.

Prognostic significance of long non-coding RNA MALAT1 for predicting the recurrence and metastasis of gallbladder cancer and its effect on cell proliferation, migration, invasion, and apoptosis

The objective of this study is to explore the role of MALAT1 as a molecular indicator in predicting the recurrence, metastasis, and prognosis of gallbladder cancer (GBC) and its effect on the proliferation, invasion, migration, and apoptosis of GBC cells in vitro. GBC tissues and adjacent normal tissues were collected from 102 patients. MALAT1 short hairpin RNA (shRNA) plasmids were first constructed to transfect the GBC-SD cells. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was applied to detect MALAT1 expression. CCK-8 assay, flow cytometry, and Transwell assay were applied to testify the cell proliferation, cell cycle, apoptosis, invasion, and migration. A receiver operating characteristic (ROC) curve was used to evaluate the values of MALAT1 in GBC recurrence, metastasis, and prognosis. COX regression analysis was applied to analyze the independent influencing factors of GBC patients' survival status. ROC curve results showed that the MALAT1 expression could be a predictor of the GBC recurrence, metastasis, and prognosis. According to the COX regression analysis, MALAT1 expression, tumor size, and TNM stage were independent influencing factors of GBC patients' survival condition. Compared with the GBC-SD cells transfected with empty plasmids, those transfected with MALAT1 shRNA plasmids showed higher apoptosis rates, weakened proliferation, migration, and invasion. In conclusion, our findings demonstrate that lncRNA MALAT1 can be considered as an indicator for evaluating the recurrence, metastasis, and prognosis of GBC patients. We also demonstrate how the overexpression of MALAT1 confers an oncogenic function in GBC.

Epithelial-to-mesenchymal transition in gallbladder cancer: from clinical evidence to cellular regulatory networks

Gallbladder cancer (GBC), with late diagnosis, rapid disease progression and early metastasis, is a highly aggressive malignant tumor found worldwide. Patients with GBC have poor survival, low curative resection rates and early recurrence. For such a lethal tumor, uncovering the mechanisms and exploring new strategies to prevent tumor progression and metastasis are critically important. Epithelial-to-mesenchymal transition (EMT) has a prominent role in the early steps of tumor progression and metastasis by initiating polarized epithelial cell transition into motile mesenchymal cells. Accumulating evidence suggests that EMT can be modulated by the cooperation of multiple mechanisms affecting common targets. Signaling pathways, transcriptional and post-transcriptional regulation and epigenetic alterations are involved in the stepwise EMT regulatory network in GBC. Loss of epithelial markers, acquisition of mesenchymal markers and dysregulation of EMT-inducing transcription factors (EMT-TFs) have been observed and are associated with the clinicopathology and prognosis of GBC patients. Therefore, EMT may be a detectable and predictable event for predicting GBC progression and metastasis in the clinic. In this review, we will provide an overview of EMT from the clinical evidence to cellular regulatory networks that have been studied thus far in clinical and basic GBC studies.

Knockdown of SOX2OT inhibits the malignant biological behaviors of glioblastoma stem cells via up-regulating the expression of miR-194-5p and miR-122

Background

Accumulating evidence has highlighted the potential role of long non-coding RNAs (lncRNAs) in the biological behaviors of glioblastoma stem cells (GSCs). Here, we elucidated the function and possible molecular mechanisms of the effect of lncRNA-SOX2OT on the biological behaviors of GSCs.

Results

Real-time PCR demonstrated that SOX2OT expression was up-regulated in glioma tissues and GSCs. Knockdown of SOX2OT inhibited the proliferation, migration and invasion of GSCs, and promoted GSCs apoptosis. MiR-194-5p and miR-122 were down-regulated in human glioma tissues and GSCs, and miR-194-5p and miR-122 respectively exerted tumor-suppressive functions by inhibiting the proliferation, migration and invasion of GSCs, while promoting GSCs apoptosis. Knockdown of SOX2OT significantly increased the expression of miR-194-5p and miR-122 in GSCs. Dual-luciferase reporter assay revealed that SOX2OT bound to both miR-194-5p and miR-122. SOX3 and TDGF-1 were up-regulated in human glioma tissues and GSCs. Knockdown of SOX3 inhibited the proliferation, migration and invasion of GSCs, promoted GSCs apoptosis, and decreased TDGF-1 mRNA and protein expression through direct binding to the TDGF-1 promoter. Over-expression of miR-194-5p and miR-122 decreased the mRNA and protein expression of SOX3 by targeting its 3’UTR. Knockdown of TDGF-1 inhibited the proliferation, migration and invasion of GSCs, promoted GSCs apoptosis, and inhibited the JAK/STAT signaling pathway. Furthermore, SOX3 knockdown also inhibited the SOX2OT expression through direct binding to the SOX2OT promoter and formed a positive feedback loop.

Conclusion

This study is the first to demonstrate that the SOX2OT-miR-194-5p/miR-122-SOX3-TDGF-1 pathway forms a positive feedback loop and regulates the biological behaviors of GSCs, and these findings might provide a novel strategy for glioma treatment.

Electronic supplementary material

The online version of this article (10.1186/s12943-017-0737-1) contains supplementary material, which is available to authorized users.

The regulatory roles of long non-coding RNAs in the development of chemoresistance in breast cancer

Chemoresistance is one of the major hurdles in the treatment of breast cancer, which limits the effect of both targeted and conventional therapies in clinical settings. Therefore, understanding the mechanisms underpinning resistance is paramount for developing strategies to circumvent resistance in breast cancer patients. Several published reports have indicated that lncRNAs play a dynamic role in the regulation of both intrinsic and acquired chemoresistance through a variety of mechanisms that endow cells with a drug-resistant phenotype. Although a number of lncRNAs have been implicated in chemoresistance of breast cancer, their mechanistic roles have not been systematically reviewed. Thus, here we present a detailed review on the latest research findings and discoveries on the mechanisms of acquisition of chemoresistance in breast cancer related to lncRNAs, and how lncRNAs take part in various cancer signalling pathways involved in breast cancer cells. Knowledge obtained from this review could assist in the development of new strategies to avoid or reverse drug resistance in breast cancer chemotherapy.

The role of H19, a long non-coding RNA, in mouse liver postnatal maturation

H19 RNA is highly expressed at early postnatal ages and precipitously decreases at a specific time corresponding with increases in expression of genes important for mature liver function, such as drug metabolizing enzymes. H19’s role in the regulation of liver maturation is currently unknown. Using an H19 knockout mouse model to determine the role of H19 in liver development, we quantified gene expression for insulin growth factor signaling, Wnt signaling, key cytochrome P450 (P450) enzymes known to change as the liver develops, and fetal and adult plasma protein produced in liver. In mice lacking H19 expression, liver weights were significantly increased immediately after birth and significant increases were found in the number of actively proliferating cells. Increases in cell proliferation may be due to increases in β-catenin protein affecting Wnt signaling, increases in insulin-like growth factor 2 (IGF2) expression, and/or increases in insulin-like growth factor 1 receptor (IGF1R) expression at the protein level. Loss of targeted inhibition of IGF1R by microRNA 675 (miR-675) may be the cause of IGF1R increases, as miR-675 expression is also abrogated with loss of H19 expression in our model. P450 expression patterns were largely unchanged. No change in the production of plasma proteins was found, indicating H19 may not be important for liver maturation despite its role in controlling cell proliferation during liver growth. H19 may be important for normal liver development, and understanding how the liver matures will assist in predicting drug efficacy and toxicity in pediatric populations.