MicroRNA-214 suppresses the proliferation of human hepatocellular carcinoma cells by targeting E2F3

A thorough and current study of miR-214-related targets in cancer

Cancer is a complex genetic anomaly involving coding and non-coding transcript structural and expressive irregularities. A class of tiny non-coding RNAs known as microRNAs (miRNAs) regulates gene expression at the post-transcriptional level by binding only to messenger RNAs (mRNAs). Due to their capacity to target numerous genes, miRNAs have the potential to play a significant role in the development of tumors by controlling several biological processes, including angiogenesis, drug resistance, metastasis, apoptosis, proliferation, and drug resistance. According to several recent studies, miRNA-214 has been linked to the emergence and spread of tumors. The human genome's q24.3 arm contains the DNM3 gene, which is about 6 kb away and includes the microRNA-214. Its primary purpose was the induction of apoptosis in cancerous cells. The multifaceted and complex functions of miR-214 as a modulator in neoplastic conditions have been outlined in the current review.

miR-214 Modulates the Growth and Migration of Oral Cancer before and after Chemotherapy through Mediating ULK1

The role of miRNAs as crucial components in carcinogenesis has been well documented. However, whether and how miR-214 influences oral cancer cells' drug resistance remains to be elucidated, and its downstream targets are still under investigation. Hence, this research is aimed at determining miR-214 and ULK1 expression in oral cancer before and after chemotherapy and their correlations with cancer cell growth. Human oral normal epithelial cells and human tongue squamous cell carcinoma CAL-27 cells were cultured to detect miR-214 and ULK1 levels. It was found that before chemotherapy, miR-214 was higher, while ULK1 was underexpressed in CAL-27 cells, versus normal epithelial cells. After chemotherapy, miR-214 decreased obviously in CAL-27 cells, while ULK1 level increased significantly. In addition, autophagy-related genes (Beclin 1, mTOR, and P53) in CAL-27 cells were found to be significantly inhibited before chemotherapy and were obviously increased after chemotherapy. Moreover, to further determine the impacts of miR-214 and ULK1 on oral cancer cell growth after chemotherapy, the two were overexpressed or silenced in CAL-27 cells after transfection. We found that ULK1 could effectively decrease the activity and invasion of CAL-27 cells and increase their apoptosis level, while miR-214 could antagonize its antitumor effect. Therefore, miR-214 can be used as an early prognostic biomarker for oral cancer, and ULK1 is a new candidate therapeutic target.

MicroRNAs are critical regulators of senescence and aging in mesenchymal stem cells

MicroRNAs (miRNAs) have recently come under scrutiny for their role in various age-related diseases. Similarly, cellular senescence has been linked to disease and aging. MicroRNAs and senescence likely play an intertwined role in driving these pathologic states. In this review, we present the connection between these two drivers of age-related disease concerning mesenchymal stem cells (MSCs). First, we summarize key miRNAs that are differentially expressed in MSCs and other musculoskeletal lineage cells during senescence and aging. Additionally, we also reviewed miRNAs that are regulated via traditional senescence-associated secretory phenotype (SASP) cytokines in MSC. Lastly, we summarize miRNAs that have been found to target components of the cell cycle arrest pathways inherently activated in senescence. This review attempts to highlight potential miRNA targets for regenerative medicine applications in age-related musculoskeletal disease.

The microRNA cluster miR-214/miR-3120 prevents tumor cell switching from an epithelial to a mesenchymal-like phenotype and inhibits autophagy in gallbladder cancer

Tumor cells switch from an epithelial to a mesenchymal-like phenotype, which represents a key hallmark of human cancer metastasis, including gallbladder cancer (GBC). A large set of microRNAs (miRNAs/miRs) have been studied to elucidate their functions in initiating or inhibiting this phenotypic switching in GBC cells. In this paper, we attempted to identify the expression pattern of the miR-214/-3120 cluster and its mode of action in the context of GBC, with a specific focus being placed on their effects on EMT and autophagy in GBC cells. Human GBC cells GBC-SD were assayed for their migration, invasion, and autophagy using the Transwell chamber system, MDC staining, and transmission electron microscopy. The tumorigenicity and metastatic behavior of GBC-SD cells were tested in nude mice. The expression of EMT- and autophagy-specific markers (E-cadherin, N-cadherin, vimentin, ATG5, LC3II/LC3I, and Beclin1) was analyzed in cultured GBC-SD cells and in human GBC-SD xenografts. The E2F3 luciferase reporter activity in the presence of miR-214/-3120 was evaluated by a dual luciferase assay. The miR-214/-3120 was downregulated in GBC. Exogenous miR-214/-3120 inhibited the phenotypic switching of GBC cells from epithelial to mesenchymal, prevented autophagy, and suppressed the tumorigenicity and metastatic behavior of GBC-SD cells in vitro and in vivo. E2F3 was demonstrated to be the target gene of miR-214/-3120, and its knockdown in part mimicked the effect of miR-214/-3120 on the EMT, autophagy, tumorigenicity, and metastatic behavior of GBC-SD cells. These results demonstrated that the miR-214/-3120 cluster blocks the process of EMT and autophagy to limit GBC metastasis by repressing E2F3 expression.

MiRNA-610 acts as a tumour suppressor to depress the cisplatin resistance in hepatocellular carcinoma through targeted silencing of hepatoma-derived growth factor

INTRODUCTION

Hepatic malignancy is one of the most common malignant neoplasms around the globe, and hepatocellular carcinoma (HCC) is the most common type. In this study, the roles and mechanisms of MiRNA-610 in the chemo resistance of HCC will be discussed.

MATERIAL AND METHODS

The expression of MiRNA-610 and hepatoma-derived growth factor (HDGF) in HCC tissues and cell line was detected by quantitative real-time PCR. The proliferation and chemo resistance were analysed by MTT assay. Flow cytometry was used to examine the apoptosis rate. Luciferase reporter assay was used to verify the correlation between MiRNA-610 and HDGF. HDGF protein expression was detected by Western blot.

RESULTS

Our study confirmed the low-expression of MiRNA-610 in HCC tissues and cell line. Its low expression was related to high T stages and poor differentiation of HCC, and was a prognostic factor for HCC. MiRNA-610 upregulation inhibited cell proliferation and induced apoptosis of HepG2 cells. MiRNA-610 enhancement decreased the half maximal inhibitory concentration for cisplatin (DDP) and depressed the DDP resistance in HepG2 cells. The specific correlation between MiRNA-610 and HDGF was tested by luciferase reporter assay and western blot. The transfection with HDGF expression vector up-regulated the expression of HDGF protein silenced by MiRNA-610 enhancement. HDGF overexpression was found to reverse partly the regulatory roles of MiRNA-610 on malignancy and DDP resistance.

CONCLUSIONS

MiRNA-610 not only played a tumour suppressor role in HCC but also affected chemo resistance to DDP. This role is mainly mediated through targeted silencing of the HDGF gene, which may offer a new potential therapeutic target and improve the clinical therapeutic effect for HCC.

6mer Seed Toxicity in Viral microRNAs

MicroRNAs (miRNAs) are short double-stranded noncoding RNAs (19-23 nucleotides) that regulate gene expression by suppressing mRNAs through RNA interference. Targeting is determined by the seed sequence (position 2-7/8) of the mature miRNA. A minimal G-rich seed of just six nucleotides is highly toxic to cells by targeting genes essential for cell survival. A screen of 215 miRNAs encoded by 17 human pathogenic viruses (v-miRNAs) now suggests that a number of v-miRNAs can kill cells through a G-rich 6mer sequence embedded in their seed. Specifically, we demonstrate that miR-K12-6-5p, an oncoviral mimic of the tumor suppressive miR-15/16 family encoded by human Kaposi sarcoma-associated herpes virus, harbors a noncanonical toxic 6mer seed (position 3-8) and that v-miRNAs are more likely than cellular miRNAs to utilize a noncanonical 6mer seed. Our data suggest that during evolution viruses evolved to use 6mer seed toxicity to kill cells.

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Tumor suppressive miR-15/16-5p with a toxic 6mer seed targets survival genes

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kshv-miR-K12-6-5p, a paralog of hsa-miR-15/16-5p carries an offset toxic 6mer seed

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A screen of 215 viral miRNAs identifies miRNAs that contain a toxic 6mer seed

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Many human viral miRNAs have the capacity to kill through 6mer seed toxicity

Promising diagnostic and prognostic value of E2Fs in human hepatocellular carcinoma

Background

A growing body of evidence suggests that E2Fs, by regulating gene expression related to cell cycle progression and other cellular processes, play a pivotal role in human cancer. However, the distinct roles of each E2F in the development and treatment of hepatocellular carcinoma (HCC) remain unknown. In the present study, the mRNA expression and prognostic value of different E2Fs in HCC are analyzed.

Materials and methods

Transcriptional and survival data related to E2F expression in patients with HCC were obtained through ONCOMINE and UALCAN databases. Survival analysis plots were drawn with Kaplan-Meier Plotter. The sequence alteration data for E2Fs were obtained from The Cancer Genome Atlas and c-BioPortal. Gene functional enrichment analyses were performed in Database for Annotation, Visualization and Integrated Discovery.

Results

The mRNA expression levels of E2F1-E2F8 were all significantly upregulated in HCC patients, and high expression of each E2F was obviously related to poor prognosis. Similarly, the expression of E2Fs showed prognostic prediction value in HCC patients with different cancer stages and pathological grades. Moreover, the mutation rate of E2Fs was relatively high in HCC patients, and the DNA sequence alterations primarily occurred in E2F5, E2F3, and E2F6, which were associated with worse overall survival and disease-free survival in HCC patients. Network analysis confirmed that the expression levels of cell cycle-related genes were mostly affected by E2F mutations.

Conclusion

High expression of individual E2Fs was associated with poor prognosis in all liver cancer patients. E2Fs may be exploited as good prognostic targets for comprehensive management of HCC patients, but this notion should be further evaluated in clinical studies.

Long noncoding RNA PVT1 promotes hepatocellular carcinoma progression through regulating miR-214

BACKGROUND

Long noncoding RNAs (lncRNA) have been verified to be involved in hepatocellular carcinoma (HCC) progression. However, the potential biologic function of PVT1 in HCC is not still fully known.

METHODS

PVT1 and miR-214 were detected by qRT-PCR assays in HCC tissues and adjacent normal tissues. CCK8, cell colony and transwell invasion assays were performed to evaluate cell proliferation and invasion abilities. Western-blot assay was performed to detect the protein of E-cadherin and Vimentin. QRT-PCR, RNA immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP) assays demonstrated PVT1 regulated miR-214 expression.

RESULTS

The results showed that PVT1 was increased in HCC tissues and higher PVT1 expression was associated with tumor size, histological differentiation grade and advanced TNM stage. Furthermore, we revealed that PVT1 promoted cell proliferation and invasion in HCC. RIP and ChIP assays demonstrated that PVT1 significantly inhibited miR-214 expression by interacting with enhancer of zeste homolog 2 (EZH2).

CONCLUSIONS

Thus, these results demonstrated that PVT1/EZH2/miR-214 regulatory pathway might serve as new target for HCC treatment.

LncRNA HOXA11-AS promotes hepatocellular carcinoma progression by repressing miR-214-3p

Accumulating studies supported that lncRNAs played important roles in tumorigenesis. LncRNA HOXA11‐AS was a novel lncRNA that has been proved to involved in several tumours. However, the role of HOXA11‐AS in the development of hepatocellular carcinoma (HCC) remains to be explained. In our study, we showed that HOXA11‐AS expression was up‐regulated in the HCC tissues, and the higher expression of HOXA11‐AS was associated with the advanced stage in the HCC samples. In addition, we indicated that the expression of HOXA11‐AS was up‐regulated in HCC cell lines (Hep3B, SMMC‐7721, MHCC97‐H and BEL‐7402) compared with normal liver cell lines (HL‐7702). Overexpression of HOXA11‐AS promoted HCC proliferation and invasion and induced the epithelial‐mesenchymal transition (EMT) and knockdown of HOXA11‐AS suppressed the HCC cell proliferation and invasion. However, we showed that miR‐214‐3p expression was down‐regulated in the HCC tissues and cell lines. Ectopic expression of miR‐214‐3p suppressed HCC cell proliferation and invasion. Furthermore, we indicated that overexpression of HOXA11‐AS decreased the miR‐214‐3p expression and the expression of miR‐214‐3p was negatively related with the HOXA11‐AS expression in HCC samples. Ectopic expression of HOXA11‐AS increased HCC proliferation and invasion and induced EMT through inhibiting miR‐214‐3p expression. These data suggested that HOXA11‐AS/miR‐214‐3p axis was responsible for development of HCC.

lncRNA MIAT promotes proliferation and invasion of HCC cells via sponging miR-214

The aberrant expression of long noncoding RNAs (lncRNAs) has been involved in various human tumors including hepatocellular carcinoma (HCC). Our study aimed to investigate the potential molecular mechanism of lncRNA myocardial infarction-associated transcript (MIAT) in HCC. The expression of MIAT and micro-RNA (miR)-214 in HCC tissues and cells was examined by quantitative real-time PCR, and the levels of enhancer of zeste homolog 2 (EZH2) and β-catenin were detected by Western blot assay. Immunoprecipitation analysis was used to detect the level of H3/H4 histone acetylation. RNA pull-down assay was performed to confirm the targeting regulatory relationship between miR-214 and MIAT. Cell viability, proliferation, and invasion were analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), [³H]thymidine incorporation, and Transwell assays, respectively. BALB/c nude mice were used to establish a hepatocellular carcinoma animal model with subcutaneous injection of SK-HEP-1 cells. Upregulation of MIAT is related to the proliferation and invasion of HCC, and downregulating MIAT expression inhibited HCC cell proliferation and invasion. The H3/H4 histone acetylation level of MIAT promoter in HCC tissues was higher than that in normal tissues. MIAT negatively regulated miR-214 in HCC cells. Inhibition of miR-214 reversed the influence of MIAT downregulation on HCC cell proliferation and invasion. In nude mouse xenograft models, downregulation of MIAT markedly suppressed the tumor growth of HCC via releasing miR-214. In conclusion, lncRNA MIAT promotes the proliferation and invasion of HCC cells through sponging miR-214, which brings a novel target for the therapy and prognosis of hepatocellular carcinoma. NEW & NOTEWORTHY This is the first research showing long noncoding RNA (lncRNA) myocardial infarction-associated transcript (MIAT) to have a regulatory effect on hepatocellular carcinoma. Micro-RNA (miR)-214 could be sponged by MIAT to promote the proliferation and invasion of hepatocellular carcinoma cells. The lncRNA MIAT/miR-214 axis brings a novel insight for the therapy and prognosis of hepatocellular carcinoma.

Gene expression, regulation of DEN and HBx induced HCC mice models and comparisons of tumor, para-tumor and normal tissues

BACKGROUND

Hepatocellular carcinoma (HCC) is the leading cause of cancer mortality. Chemical and virus induction are two major risk factors, however, the potential molecular mechanisms of their differences remain elusive. In this study, to identify the similarities and differences between chemical and virus induced HCC models, we compared the gene expression profiles between DEN and HBx mice models, as well as the differences among tumor, para-tumor and normal tissues.

METHODS

We sequenced both gene and microRNA (miRNA) expression for HCC tumor tissues, para-tumor and normal liver tissues from DEN model mice (30-week-old) and downloaded the corresponding microarray expression data of HBx model from GEO database. Then differentially expressed genes (DEGs), miRNAs and transcription factors (TFs) were detected by R packages and performed functional enrichment analysis. To explore the gene regulatory network in HCC models, miRNA and TF regulatory networks were constructed by target prediction.

RESULTS

For model comparison, although DEGs between tumor and normal tissues in DEN and HBx models only had a small part of overlapping, they shared common pathways including lipid metabolism, oxidation-reduction process and immune process. For tissue comparisons in each model, genes in oxidation-reduction process were down-regulated in tumor tissues and genes in inflammatory response showed the highest expression level in para-tumor tissues. Genes highly expressed in both tumor and para-tumor tissues in two models mainly participated in immune and inflammatory response. Genes expressed in HBx model were also involved in cell proliferation and cell migration etc. Network analysis revealed that several miRNAs such as miR-381-3p, miR-142a-3p, miR-214-3p and TFs such as Egr1, Atf3 and Klf4 were the core regulators in HCC.

CONCLUSIONS

Through the comparative analyses, we found that para-tumor tissue is a highly inflammatory tissue while the tumor tissue is specific with both inflammatory and cancer signaling pathways. The DEN and HBx mice models have different gene expression pattern but shared pathways. This work will help to elucidate the molecular mechanisms underlying different HCC models.

miR-203a suppresses cell proliferation by targeting E2F transcription factor 3 in human gastric cancer

MicroRNAs (miRs) are a class of short non-coding RNAs that serve an essential role in the tumorigenesis of gastric cancer (GC). MiR-203a has been reported as a tumor repressor in various types of human cancer. In the present study, the function of miR-203a on the proliferation of GC cells was investigated. Bioinformatics analyses revealed that miR-203a targets the 3'-untranslated region of E2F transcription factor 3 (E2F3) messenger RNA. A luciferase reporter assay and western blot analysis were performed to confirm whether E2F3 was a target of miR-203a. The relative luciferase activity was decreased when overexpressing miR-203a with E2F3-wild type pmirGLO-3'-untranslated region vector, compared with the control group in HEK293 cells. Overexpression of miR-203a suppressed cell proliferation and colony formation of SGC-7901 and AGS GC cells. Inhibition of miR-203a promoted the proliferation of GC cells. Collectively, the results indicated that miR-203a may function as a tumor suppressor in GC by targeting E2F3.

MiRNAs and E2F3: a complex network of reciprocal regulations in human cancers

E2F transcription factor 3 (E2F3) is oncogenic in tumorigenesis. Alterations in E2F3 functions correspond with poor prognosis in various cancers, underscoring their status for the clinical cancer phenotype. Latest reports discovered intricate networks between microRNAs (miRNAs) and E2F3 in regulating the balance of these events, including proliferation, apoptosis, metastasis, as well as drug resistance. miRNAs are non-coding small RNAs which negatively regulate gene expressions post-transcriptionally mainly through 3′-UTR binding of target mRNAs. Increasing evidence shows that E2F3 can be activated/inhibited by numerous miRNAs whose dysregulation has been implicated in malignancy. In turn, miRNAs themselves can be transcriptionally regulated by E2F3, thus forming a negative feedback loop. These findings add a new challenging layer of complexity to E2F3 network. Current understanding of the reciprocal link between E2F3 and miRNAs in human cancers were summarized, which could help to develop potential therapeutic strategies.