MicroRNA-520b inhibits growth of hepatoma cells by targeting MEKK2 and cyclin D1

miRNAs in HCC, pathogenesis, and targets

Liver cancer is the third leading cause of cancer-related mortality worldwide. HCC, the most common type of primary liver cancer, is driven by complex genetic, epigenetic, and environmental factors. MicroRNAs, a class of naturally occurring small noncoding RNAs, play crucial roles in HCC by simultaneously modulating the expression of multiple genes in a fine-tuning manner. Significant progress has been made in understanding how miRNAs influence key oncogenic pathways, including cell proliferation, apoptosis, angiogenesis, and epithelial-mesenchymal transition (EMT), as well as their role in modulating the immune microenvironment in HCC. Due to the unexpected stability of miRNAs in the blood and fixed HCC tumors, recent advancements also highlight their potential as noninvasive diagnostic tools. Restoring or inhibiting specific miRNAs has offered promising strategies for targeted HCC treatment by suppressing malignant hepatocyte growth and enhancing antitumor immunity. In this comprehensive review, we consolidate previous research and provide the latest insights into how miRNAs regulate HCC and their therapeutic and diagnostic potential. We delve into the dysregulation of miRNA biogenesis in HCC, the roles of miRNAs in the proliferation and apoptosis of malignant hepatocytes, angiogenesis and metastasis of HCC, the immune microenvironment in HCC, and drug resistance. We also discuss the therapeutic and diagnostic potential of miRNAs and delivery approaches of miRNA drugs to overcome the limitations of current HCC treatment options. By thoroughly summarizing the roles of miRNAs in HCC, our goal is to advance the development of effective therapeutic drugs with minimal adverse effects and to establish precise tools for early diagnosis of HCC.

miRNA-338-3p inhibits the migration, invasion and proliferation of human lung adenocarcinoma cells by targeting MAP3K2

Objective: This study aimed to investigate the effects of micro ribonucleic acid (miR)-338-3p on the migration, invasion and proliferation of lung adenocarcinoma (LUAD) cells.

Methods: Bioinformatics analysis was employed to evaluate the function and expression of related genes in lung cancer. Human A549 and NCI-H1299 cells cultured to logarithmic growth stage were assigned to negative control (NC) mimic group, miR-338-3p mimic group (miR-mimic group), NC inhibitor group and miR-338-3p inhibitor group (miR-inhibitor group) treated with or without MAP3K2 overexpression (OE)-lentivirus, or TBHQ or FR180204. Transwell assay, cell colony formation assay, Western blotting and cell-cycle analysis were carried out.

Results: Bioinformatics results manifested that miR-338 and MAP3K2 were involved in LUAD. The expression levels of MAP3K2, p-ERK1/2, MMP-2, MMP-3, MMP-9, cyclin A2 and cyclin D1 were increased after addition of miR-338-3p inhibitor, consistent with the raised amount of LUAD cells in migration and invasion experiments and number of colonies formed, as well as the cell cycle, but miR-338-3p mimic reversed these results. Moreover, MAP3K2 overexpression elevated the level of p-ERK1/2. Meanwhile, after treatment with TBHQ or FR180204, the influence of miR-338-3p inhibitor or mimic was also verified.

Conclusions: MiR-338-3p overexpression can modulate the ERK1/2 signaling pathway by targeting MAP3K2, thus inhibiting the migration, invasion and proliferation of human LUAD cells.

Hepatitis B Viral Protein HBx and the Molecular Mechanisms Modulating the Hallmarks of Hepatocellular Carcinoma: A Comprehensive Review

With 296 million cases estimated worldwide, chronic hepatitis B virus (HBV) infection is the most common risk factor for hepatocellular carcinoma (HCC). HBV-encoded oncogene X protein (HBx), a key multifunctional regulatory protein, drives viral replication and interferes with several cellular signalling pathways that drive virus-associated hepatocarcinogenesis. This review article provides a comprehensive overview of the role of HBx in modulating the various hallmarks of HCC by supporting tumour initiation, progression, invasion and metastasis. Understanding HBx-mediated dimensions of complexity in driving liver malignancies could provide the key to unlocking novel and repurposed combinatorial therapies to combat HCC.

Differential expression of microRNA between triple negative breast cancer patients of African American and European American descent

There are racial disparities in the outcome of triple negative breast cancer (TNBC) patients between women of African ancestry and women of European ancestry, even after accounting for lifestyle, socioeconomic and clinical factors. MicroRNA (miRNA) are non-coding molecules whose level of expression is associated with cancer suppression, proliferation and drug resistance; therefore, these have potential for biomarker applications in cancers including TNBC. Historically, miRNAs up-regulated in African American (AA) patients have received less attention than for patients of European ancestry. Using laser capture microdissection (LCM) to acquire ultrapure tumor cell samples, miRNA expression was evaluated in 15 AA and 15 European American (EA) TNBC patients. Tumor sections were evaluated using RNA extraction followed by miRNA analysis and profiling. Results were compared based on ethnicity and method of tissue fixation. miRNAs that showed high differential expression in AA TNBC patients compared to EA included: miR-19a, miR-192, miR-302a, miR-302b, miR-302c, miR-335, miR-520b, miR-520f and miR-645. LCM is a useful technique for isolation of tumor cells. We found a greater abundance of RNA in frozen samples compared to formalin fixed, paraffin embedded samples. miRNA appears to be a useful biomarker for TNBC to improve diagnosis and treatment.

MiR-520b inhibits endothelial activation by targeting NF-κB p65-VCAM1 axis

MiR-520b belongs to the miR-373/520 family, is expressed only in human and nonhuman primates. Previous reports indicated that the expression of miR-520b was repressed in human atherosclerotic plaque tissue compared with healthy vessels. However, the role of miR-520b in coronary artery disease still remains to be uncovered. In this study, we demonstrated that endothelial cells (ECs) in human atherosclerotic plaques expressed miR-520b and aimed to elucidate the impact of miR-520b on EC activation and inflammatory response. To determine the potential targets of miR-520b, we performed RNA-seq analysis by transfecting miR-520b mimics in ECs. The quantitative real-time PCR (qPCR) validation suggested that miR-520b over-expression reduced pro-inflammatory gene expression (e.g. ICAM1, VCAM1, SELE) while the inhibition of miR-520b induced their expression. By combining bioinformatics prediction and functional assays, we identified that RELA (Nuclear Factor-κB (NF-κB) Transcription Factor P65) was a direct target of miR-520b. Moreover, miR-520b mimics attenuated monocyte adhesion and monocyte trans-endothelial migration (the initial steps of atherosclerotic formation) in response to lipopolysaccharides (LPS) stimulation. Re-expression of a non-miR-targetable version of p65 could rescue the reduced monocyte cell attachment, suggesting that this process is NF-κB p65 dependent. MiR-520b reduced the abundance of NF-κB p65 in cytoplasmic fractions without corresponding increase in nuclear fractions, indicating that this regulation is independent of p65 translocation process. MiR-520b mimics attenuated the activity of VCAM-1 promoter, whereas miR-520b inhibitor activated its activity. However, miR-520b inhibitor had no effect on promoter activity containing the mutated NF-κB p65 binding sites, strongly demonstrating that the impact of miR-520b on VCAM1 gene is mediated by NF-κB p65. Thus, we concluded that miR-520b suppressed EC inflammation and the cross-talk between monocytes and ECs by down-regulating NF-κB p65-ICAM1/VCAM1 axis and might serve as a potential therapeutic target for EC dysfunction and atherosclerosis.

FGF16 regulated by miR-520b enhances the cell proliferation of lung cancer

FGF16 is implicated in the progression of some specific types of cancers, such as embryonic carcinoma, ovarian cancer, and liver cancer. Yet, the function of FGF16 in the development of lung cancer remains largely unexplored. In this study, we present the novel function of FGF16 and the regulation of miR-520b on FGF16 in lung cancer progression. In clinical lung cancer tissues, FGF16 is overexpressed and its high level is negatively associated with the low level of miR-520b. Furthermore, both the transcription and translation levels of FGF16 are restrained by miR-520b in lung cancer cells. For the regulatory mechanism investigation, miR-520b is able to directly bind to the 3′-untranslated region (3′UTR) of FGF16 mRNA, leading to its mRNA cleavage in the cells. Functionally, miR-520b reduces the growth of lung cancer and its inhibitor anti-miR520b is able to promote the growth through competing endogenous miR-520b. Moreover, FGF16 silence using RNA interference is capable of doing great damage to anti-miR-520b-accelerated growth of lung cancer. Thus, our finding indicates that FGF16 is a new target gene of miR-520b in lung cancer. For lung cancer, FGF16 may serve as a novel biomarker and miR-520b/FGF16 may be useful in clinical treatment.

MicroRNAs in the Pathogenesis of Hepatocellular Carcinoma: A Review

Simple Summary

Hepatocellular carcinoma (HCC) is one of the most frequently occurring cancers, and the prognosis for late-stage HCC remains poor. A better understanding of the pathogenesis of HCC is expected to improve outcomes. MicroRNAs (miRNAs) are small, noncoding, single-stranded RNAs that regulate the expression of various target genes, including those in cancer-associated genomic regions or fragile sites in various human cancers. We summarize the central roles of miRNAs in the pathogenesis of HCC and discuss their potential utility as valuable biomarkers and new therapeutic agents for HCC.

Abstract

Hepatocellular carcinoma (HCC) is the seventh most frequent cancer and the fourth leading cause of cancer mortality worldwide. Despite substantial advances in therapeutic strategies, the prognosis of late-stage HCC remains dismal because of the high recurrence rate. A better understanding of the etiology of HCC is therefore necessary to improve outcomes. MicroRNAs (miRNAs) are small, endogenous, noncoding, single-stranded RNAs that modulate the expression of their target genes at the posttranscriptional and translational levels. Aberrant expression of miRNAs has frequently been detected in cancer-associated genomic regions or fragile sites in various human cancers and has been observed in both HCC cells and tissues. The precise patterns of aberrant miRNA expression differ depending on disease etiology, including various causes of hepatocarcinogenesis, such as viral hepatitis, alcoholic liver disease, or nonalcoholic steatohepatitis. However, little is known about the underlying mechanisms and the association of miRNAs with the pathogenesis of HCC of various etiologies. In the present review, we summarize the key mechanisms of miRNAs in the pathogenesis of HCC and emphasize their potential utility as valuable diagnostic and prognostic biomarkers, as well as innovative therapeutic targets, in HCC diagnosis and treatment.

HCP5 Promotes Proliferation and Contributes to Cisplatin Resistance in Gastric Cancer Through miR-519d/HMGA1 Axis

Introduction

The long-non-coding RNA HCP5 (HLA complex P5) has been extensively linked to the ability of cancer cells to resist chemotherapeutic interventions. Here, we investigated the role of HCP5 in gastric cancer (GC) which to-date has been poorly characterized. Our results indicated that HCP5 expression was up-regulated in GC cells.

Methods

HCP5, miR-519d, and high mobility group A1 (HMGA1) expression levels in GC cells were measured using quantitative real-time PCR (qRT-PCR) and Western blot analysis. Drug sensitivity and apoptosis of tumor cells were assessed using cell counting kit-8, flow cytometry, and caspase activity assay. Bioinformatics and luciferase reporter assays were employed for analyzing the interactions between HCP5, miR-519d, and HMGA1.

Results

HCP5 knockdown suppressed proliferation and weakened the resistance to cisplatin (DDP) of GC cells. miR-519d was down-regulated in GC cells and sponged by HCP5. HMGA1 was directly inhibited by miR-519d and its expression was up-regulated in GC cells. HCP5 exacerbated the resistance to cisplatin of GC cells in vitro by enhancing HMGA1 expression via sponging miR-519d.

Conclusion

In summary, HCP5 promoted proliferation and contributed to DDP resistance in GC cells through miR-519d/HMGA1 axis.

CircPUM1 promotes hepatocellular carcinoma progression through the miR-1208/MAP3K2 axis

Hepatocellular carcinoma (HCC) is a common disease with a significant mortality, and there is no effective treatment for advanced patients. Growing evidence indicates that circRNAs are closely related to HCC progression, may be used as biomarkers and targets for the diagnosis and treatment of HCC. Recent researches have shown that circPUM1 may play an oncogene role in a variety of human cancers, but its role in HCC development has not been reported. Our study found that circPUM1 could promote the proliferation, migration and invasion of HCC cells in vitro. In addition, in vivo studies showed that circPUM1 could increase the development of HCC tumours and regulate the expression of EMT-related proteins. Furthermore, we demonstrated that circPUM1 could promote the development of HCC by up-regulating the expression of MAP3K2 via sponging miR-1208. Our study suggested that circPUM1 may be a potential therapeutic target for HCC.

MicroRNA-335 targets the MEK/ERK pathway to regulate the proliferation and metastasis of colon cancer

Several studies have proved the tumor-suppressive effects of miR-335 but its role in colon cancer via regulation of the Raf/MEK/ERK signalling pathway is yet unknown. As such the main motive of conducting the present study was to elucidate the role of miR-335 in colon cancer via regulation of Raf/MEK/ERK signalling pathway and to explore its therapeutic potential. The results revealed significant (P < 0.05) downregulation of miR-335 in colon cancer and its overexpression led to a significant (P < 0.05) decline in viability of the HT-29 and SW948 cells. The TUNNEL assay showed miR-335 promotes apoptosis in the HT-29 and SW948 colon cancer cells and is also associated with increase in Bax and decrease in Bcl-2 expression. The results also revealed that miR-335 overexpression enhances the sensitivity of the HT-29 and SW948 cells to the apoptotic effects of cisplatin. From the transwell assays, it was found that the migration of the HT-29 and SW948 cells was decreased by 53% and 45% and while as invasion was decreased by 49% and 42% respectively (P < 0.05). Finally, western blot analysis showed that miR-335 blocks the Raf/MEK/ERK signalling pathway in HT-29 colon cancer cells. The results of in vivo study showed that miR-335 also exhibits tumor-suppressive effects on xenografted tumors. Taken together, it is concluded that miR-335 acts as tumor-suppressor in colon cancer and may exhibit therapeutic implications in its treatment.

MicroRNA signature in hepatocellular carcinoma patients: identification of potential markers

MicroRNAs (miRNAs) play important roles in liver pathologies and they are potential biomarkers for diagnosis of liver diseases progression. Changes in miRNA sera expression can be used as non-invasive biomarkers for hepatocellular carcinoma (HCC). The aim of the study was to identify the miRNome profiling of HCC and its diagnostic value in distinguishing HCC from healthy individuals. Expression profiles of miRNAs in serum samples of 20 HCC patients and 10 healthy controls were detected. Whole miRNome profiling was done using next generation sequencing. Receiver operating characteristic (ROC) analysis was performed to assess the diagnostic performance of the deregulated miRNAs for discriminating HCC cases from healthy controls. MiRNA 142 was highly expressed in HCC (P value = 0.023) while miRNAs 191, 22, and 126 were higher in the controls (P value = 0.005, 0.034, 0.010 respectively). We have identified 5 novel miRNAs and they were highly expressed in HCC than controls. Analysis of ROC curve demonstrated that these deregulated miRNAs can be used as a reliable biomarker for detection of HCC with high diagnostic accuracy (AUC = 0.93). We have detected a panel of serum miRNAs that can be used as a reliable noninvasive screening biomarker of HCC. The study recommends further research to shed light on a possible role of the newly discovered novel miRNAs in HCC pathogenesis.

MIR205HG acts as a ceRNA to expedite cell proliferation and progression in lung squamous cell carcinoma via targeting miR-299-3p/MAP3K2 axis

INTRODUCTION

Long noncoding RNAs (lncRNAs) have been associated with many types of cancers, but their molecular mechanisms in lung squamous cell carcinoma (LUSC) have not been fully studied. Therefore, the current study investigated the regulation role of microRNA-205 host gene (MIR205HG) in LUSC and recognized the target genes managed by this lncRNA.

METHODS

MIR205HG expression was assessed by the quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The effects of silenced MIR205HG on cell biological behaviors were detected by colony formation assay, transwell assay, flow cytometry analysis and western blot analysis. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay were utilized to proof the binding relationship between miR-299-3p and MIR205HG/mitogen-activated protein kinase kinase kinase 2 (MAP 3 K2).

RESULTS

The expression levels of MIR205HG in LUSC tissues and cell lines were obviously up-regulated. Down-regulation of MIR205HG expression remarkably reduced cell proliferation, migration and epithelial-to-mesenchymal transition (EMT) progression, whereas promoted cell apoptosis. MIR205HG could bind with miR-299-3p and down-regulation of MIR205HG elevated miR-299-3p expression. MAP 3 K2 acted as the target gene of miR-299-3p and was up-regulated by MIR205HG overexpression. Overexpressing MAP 3 K2 could counteract the effects of down-regulating MIR205HG on LUSC progression to some degree.

CONCLUSION

MIR205HG acts as a competing endogenous RNA (ceRNA) to expedite cell proliferation and progression via targeting miR-299-3p in LUSC.

CircFAT1 Suppresses Colorectal Cancer Development Through Regulating miR-520b/UHRF1 Axis or miR-302c-3p/UHRF1 Axis

Background: It was reported that circular RNAs (circRNAs) exerted important functions in various human cancers. However, the function of circFAT1 was less known. The purpose of this study was to reveal the functional mechanism of circFAT1 in colorectal cancer (CRC). Materials and Methods: Quantitative real-time polymerase chain reaction and Western blot assay were used to detect the levels of genes. Cell proliferation ability was assessed by 3-(4, 5-dimethyl-2-thiazoyl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Flow cytometry was used to investigate cell apoptosis rate. The glucose consumption and lactate production were determined using related kits. Furthermore, the interaction between circFAT1 or ubiquitin-like PHD and RING finger domain-containing protein 1 (UHRF1) and miR-520b or miR-302c-3p was predicted by starbase3.0, and then confirmed by the dual-luciferase reporter assay. Besides, xenograft experiment was performed to analyze the effect of circFAT1 on tumor growth in vivo. Results: The levels of circFAT1 and UHRF1 were increased, as well as the levels of miR-520b and miR-302c-3p were decreased in CRC tissues and cells. CircFAT1 knockdown suppressed cell proliferation, cycle, and glycolysis as well as induced apoptosis. Interestingly, circFAT1 was a sponge of miR-520b and miR-302c-3p, and miR-520b and miR-302c-3p could target UHRF1. Both miR-520b overexpression and miR-302c-3p overexpression inhibited CRC cell growth. Furthermore, both miR-520b knockdown and miR-302c-3p depletion weakened the effect of circFAT1 knockdown on the growth of CRC cells. Besides, circFAT1 depletion repressed tumor growth in vivo. Conclusion: The authors' findings suggested that circFAT1 upregulated UHRF1 to affect CRC cell proliferation, apoptosis, and glycolysis through targeting miR-520b and miR-302c-3p, providing theoretical basis for the treatment of CRC.

MicroRNA-520b targets interlukin-2 to regulate the growth, metastasis and drug sensitivity of liver cancer cells

Liver cancer is ranked as the 5^th major type of cancer and is responsible for significant number of human deaths across the world. Recent investigations have shown microRNAs (miRs) to be involved in diverse cellular processes. Additionally, they have been shown to exhibit therapeutic implications in treatment of different diseases including cancer. This study investigated the role and therapeutic implications of miR-520b in liver cancer. The results of the present study revealed significant downregulation of miR-520b in liver cancer cell lines. Overexpression of miR-520b suppresses the growth of the SNU-182 and HepG2 cells by triggering apoptosis. This was also accompanied by upsurge of Bax and Caspase-3 and depletion of Bcl-2 in SNU-182 and HepG2 cells. Additionally, miR-520b caused a significant decrease in the migratory and invasive potential of the SNU-182 and HepG2 cells and enhanced their chemosensitivity to Gemcitabine. Bioinformatic analysis and the dual luciferase showed that miR-520b targets IL2 in HepG2 cells. Suppression of IL2 inhibits the growth of the HepG2 cells while as IL2 overexpression could avoid the tumor suppressive effects of miR-520b in HepG2 cells. Taken together, miR-520b may prove to be essential therapeutic target in liver cancer treatment and warrants further research endeavours.

MLK3 is a newly identified microRNA-520b target that regulates liver cancer cell migration

The roles of microRNAs (miRNAs) in liver cancer have attracted much attention in recent years. In this study, we demonstrate that miR-520b is downregulated in MHCC-97H cells, a liver cancer cell line with high potential of metastasis, compared with MHCC-97L cells which has a low potential of metastasis. Furthermore, the enhanced expression of miR-520b could inhibit liver cancer cell migration, while silencing its expression resulted in increased migration. Mixed lineage kinase 3 (MLK3) was identified as a direct and functional new target of miR-520b. This regulation was also confirmed by luciferase reporter assays. In addition, our results showed that overexpression of the MLK3 expression partially reversed the effect of miR-520b on liver cancer cell migration, indicating that MLK3 contributes to the migration in liver cancer. The newly identified miR-520b/MLK3 axis partially elucidates the molecular mechanism of liver cancer cell migration and represents a new potential therapeutic target for liver cancer treatment.

miR-520b Promotes Breast Cancer Stemness Through Hippo/YAP Signaling Pathway

Introduction

The breast cancer stem cells contribute to the initiation, progression, recurrence, metastasis as well as resistance of breast cancer. However, the mechanisms underlying the maintenance of breast cancer stemness have not been fully understood.

Materials and methods

TCGA and GEO data were used for measuring miR-520b expression in breast cancer tissues. Kaplan-meier analysis was used for determining the relationship between miR-520b expression level and the prognosis of patients. Genetic manipulation was performed by lentivirus system and miR-520b inhibitor was used for knockdown of miR-520b. qRT-PCR and Western blot were employed to determine the mRNA and protein levels, respectively. The stemness and EMT (Epithelial to mesenchymal transition) were assessed by sphere-formation and transwell assay as well as the expression of the related markers. The target genes of miR-520b were identified using the online database starBase V3.0.

Results

miR-520b is upregulated in cancer tissues of breast cancer patients and predicts poor prognosis. Upregulation of miR-520b was found in breast cancer stem cells. Ectopic expression of miR-520b promotes the stemness of the breast cancer cells, conversely, depletion of miR-520b attenuates the stemness of these cells. miR-520b positively regulates Hippo/YAP signaling pathway and overexpression of LAST2 abolished the effect of miR-520b on the stemness of breast cancer cells.

Conclusion

miR-520b promotes the stemness of breast cancer patients by activating Hippo/YAP signaling via targeting LATS2.

Identification of microRNAs associated with the aggressiveness of prolactin pituitary tumors using bioinformatic analysis

Aggressive prolactin pituitary tumors, which exhibit aggressive behaviors and resistance to conventional treatments, are a huge challenge for neurosurgeons. Many studies have investigated the roles of microRNAs (miRNAs) in pituitary tumorigenesis, invasion and metastasis, but few have explored aggressiveness‑associated miRNAs in aggressive pituitary tumors. Differentially expressed miRNAs (DEMs) between aggressive and nonaggressive prolactin pituitary tumors were screened using the GSE46294 miRNA expression profile downloaded from the GEO database. The potential target genes of the top three most highly upregulated and downregulated DEMs were predicted by miRTarBase, and potential functional annotation and pathway enrichment analysis were performed using the DAVID database. Protein‑protein interaction (PPI) and miRNA‑hub gene interaction networks were constructed by Cytoscape software. A total of 43 DEMs were identified, including 19 upregulated and 24 downregulated miRNAs, between aggressive and nonaggressive prolactin pituitary tumors. One hundred and seventy and 680 target genes were predicted for the top three most highly upregulated and downregulated miRNAs, respectively, and these genes were involved in functional enrichment pathways, such as regulation of transcription from RNA polymerase II promoter, DNA‑templated transcription, Wnt signaling pathway, protein binding, and transcription factor activity (sequence‑specific DNA binding). In the PPI network, the top 10 genes with the highest degree of connectivity of the upregulated and downregulated DEMs were selected as hub genes. By constructing an miRNA‑hub gene network, it was found that most hub genes were potentially modulated by hsa‑miR‑489 and hsa‑miR‑520b. Targeting hsa‑miR‑489 and hsa‑miR‑520b may provide new clues for the diagnosis and treatment of aggressive prolactin pituitary tumors.

miR-302a inhibits human HepG2 and SMMC-7721 cells proliferation and promotes apoptosis by targeting MAP3K2 and PBX3

Hepatocellular carcinoma (HCC) is the most common liver cancer and has a poor prognosis. miR-302a is an important regulator of tumor occurrence and deterioration, while MAP3K2 and PBX3 genes are involved in cancer cell proliferation and apoptosis. In this study, the expression of miR-302a and MAP3K2/PBX3 were evaluated by qPCR in liver cancer cell lines. Next, the target relationship between miR-302a and MAP3K2/PBX3 was verified using luciferase assays. Meanwhile, the expression correlation between miR-302a and target genes was analyzed in cancer tissue and para-cancerous tissue. In addition, an increased miR-302a level in HepG2 cells and SMMC-7721 cells were achieved through transfection with miR-302a mimics, and the effects on HepG2 cell and SMMC-7721 cell proliferation, apoptosis and MAPK pathways were determined using MTT, flow cytometry, qPCR and western blot assays. The results showed that liver cancer cell lines exhibited low miR-302a expression and MAP3K2 and PBX3 were confirmed to be the target genes of miR-302a. Meanwhile, the HE results showed that cells became enlarged with loose cytoplasm and formed balloon-like lesions in HCC specimens and we found a significant negative correlation between miR-302a and MAP3K2/PBX3 expression. In addition, treatment with miR-302a mimics inhibited HepG2 cells and SMMC-7721 cells proliferation and increased the apoptosis rate. Further research revealed that the MAPK key factors p-p38, p-ERK1/2 and p-JNK were significantly reduced in miR-302a transfected cells and MAP3K2/PBX3 silenced cells. Besides, MAP3K2 and PBX3 overexpression in miR-302a mimics-treated cells exerted the opposite effects. In conclusion, miR-302a inhibited proliferation and promoted apoptosis in human hepatoma cells by targeting MAP3K2 and PBX3.

MiRNAs differentially expressed in skeletal muscle of animals with divergent estimated breeding values for beef tenderness

Background

MicroRNAs (miRNAs) are small noncoding RNAs of approximately 22 nucleotides, highly conserved among species, which modulate gene expression by cleaving messenger RNA target or inhibiting translation. MiRNAs are involved in the regulation of many processes including cell proliferation, differentiation, neurogenesis, angiogenesis, and apoptosis. Beef tenderness is an organoleptic characteristic of great influence in the acceptance of meat by consumers. Previous studies have shown that collagen level, marbling, apoptosis and proteolysis are among the many factors that affect beef tenderness. Considering that miRNAs can modulate gene expression, this study was designed to identify differentially expressed miRNAs that could be modulating biological processes involved with beef tenderness.

Results

Deep sequence analysis of miRNA libraries from longissimus thoracis muscle allowed the identification of 42 novel and 308 known miRNAs. Among the known miRNAs, seven were specifically expressed in skeletal muscle. Differential expression analysis between animals with high (H) and low (L) estimated breeding values for shear force (EBVSF) revealed bta-mir-182 and bta-mir-183 are up-regulated (q value < 0.05) in animals with L EBVSF, and bta-mir-338 is up-regulated in animals with H EBVSF. The number of bovine predicted targets for bta-mir-182, bta-mir-183 and bta-mir-338 were 811, 281 and 222, respectively, which correspond to 1204 unique target genes. Among these, four of them, MEF2C, MAP3K2, MTDH and TNRC6B were common targets of the three differentially expressed miRNAs. The functional analysis identified important pathways related to tenderness such as apoptosis and the calpain–calpastatin system.

Conclusion

The results obtained indicate the importance of miRNAs in the regulatory mechanisms that influence muscle proteolysis and meat tenderness and contribute to our better understanding of the role of miRNAs in biological processes associated with beef tenderness.

Electronic supplementary material

The online version of this article (10.1186/s12867-018-0118-3) contains supplementary material, which is available to authorized users.

MiR-520b restrains cell growth by targeting HDAC4 in lung cancer

BACKGROUND

MicroRNAs (miRNAs) function as tumor promoting or tumor suppressing factors in many cancers. MiR-520b contributes to progression in head-neck and liver cancers, spinal osteosarcoma, and glioma; however, the association of miR-520b with lung cancer progression remains unknown. In this investigation, we explore the effect of miR-520b targeting HDAC4 on lung cancer growth.

METHODS

The regulation of miR-520b or its inhibitor on HDAC4 expression was analyzed using Western blot analysis. After treatment of miR-520b or its inhibitor, miR-520b and HDAC4 levels were examined using quantitative real time-PCR. The modulation of miR-520b on HDAC4 was investigated by luciferase reporter gene assay. Cell proliferation evaluation was performed using colony formation and methyl-thiazolyl-tetrazolium assays. The correlation between miR-520b and HDAC4 in human clinical samples was verified using Pearson's correlation coefficient.

RESULTS

An obvious decrease in HDAC4 expression was observed in lung cancer A549 cells treated with different doses of miR-520b. The miR-520b inhibitor enhanced HDAC4 expression in lung cancer cells. Bioinformatics predicted the targeting of miR-520b on HDAC4. MiR-520b directly targeted the 3' untranslated region of HDAC4. The introduction of miR-520b obviously inhibited cell proliferation in vitro. Anti-miR-520b was capable of accelerating lung cancer cell proliferation; however, HDAC4 knockdown destroyed anti-miR-520b-induced cell proliferation. Finally, a negative correlation between miR-520b and HDAC4 was observed in clinical human lung cancer samples.

CONCLUSION

MiR-520b decreases HDAC4 expression to control cell proliferation in lung cancer.

MEKK2 and MEKK3 suppress Hedgehog pathway-dependent medulloblastoma by inhibiting GLI1 function

Hedgehog (Hh) pathway plays a pivotal role in diverse aspects of development and postnatal physiology. Perturbation of Hh signaling and activation of GLI1 (glioma-associated oncogene 1), a dedicated transcription factor for Hh pathway, are highly associated with several cancers, such as medulloblastoma and basal cell carcinoma. Dynamic and precise control of GLI1 activity is thus important to ensure proper homeostasis and tumorigenesis. Here we show that MEKK2 (MAP3K2) and MEKK3 (MAP3K3) inhibit GLI1 transcriptional activity and oncogenic function through phosphorylation on multiple Ser/Thr sites of GLI1, which reduces GLI1 protein stability, DNA-binding ability, and increases the association of GLI1 with SUFU. Interestingly, MEKK2 and MEKK3 are responsible for FGF2-mediated inhibition on Hh signaling. Moreover, expression of MEKK2 and MEKK3 inhibits medulloblastoma cell proliferation and negatively correlates with Hh pathway activity in medulloblastoma clinical samples. Together, these findings reveal a novel noncanonical GLI1 regulation and provide a potential therapeutic target for the treatment of cancers with aberrant Hh pathway activation, such as medulloblastoma.

MiR-520d-3p antitumor activity in human breast cancer via post-transcriptional regulation of spindle and kinetochore associated 2 expression

MicroRNAs (miRNAs) play an important role in human tumorigenesis as oncogenes or tumor suppressors by directly binding to the 3'-untranslated region of their target mRNAs. MiR-520d-3p has been reported as a tumor suppressor gene in ovarian cancer and gastric cancer, while the function of miR-520d-3p in human breast cancers is still uninvolved. In this study, we initially identified that the expression of miR-520d-3p was significantly reduced in breast cancer specimens and cell lines. The restoration of miR-520d-3p expression not only reduced breast cancer cell viability by causing the accumulation of G2 phase and cell apoptosis, but also inhibited tumorigenicity in vivo. In addition, as a critical target of miR-520d-3p, the activity of spindle and kinetochore associated 2 (SKA2) was greatly inhibited by miR-520d-3p, and overexpression of miR-520d-3p decreased the expression of SKA2. SKA2 downregulation suppressed cell viability, whereas restoration of SKA2 expression significantly reversed the inhibitory effects of miR-520d-3p antitumor activity. Furthermore, SKA2 was frequently overexpressed in clinical specimens and cell lines, and the expression levels were statistically inversely correlated with miR-520d-3p expression. In conclusion, our data demonstrated that miR-520d-3p antitumor activity is achieved by targeting the SKA2 in human breast cancer cells, suggesting that miR-520d-3p may be a potential target molecule for the therapy.

Discovery and characterization of an iminocoumarin scaffold as an inhibitor of MEKK2 (MAP3K2)

The kinase MEKK2 (MAP3K2) activates the MEK5/ERK5 cell signaling pathway and may play an important role in tumor growth and metastasis. Thus, MEKK2 may represent a novel kinase target for cancer. In order to identify inhibitors of MEKK2, we screened a library of compounds using a high throughput MEKK2 intrinsic ATPase enzyme assay. We identified two hits with validated structures and confirmed activity in the primary assay (IC₅₀ values = 322 nM and 7.7 μM) and two orthogonal MEKK2 biochemical assays. Compound 1, the more potent hit, was the subject of further investigation. Limited structure-activity relationship (SAR) studies were performed on this iminocoumarin hit which resulted in ≥20-fold more potent analogs (e.g. 8 and 16 nM IC₅₀). Two analogs had improved selectivity in a 50-member kinase profiling panel compared to the hit. These studies suggested that substitutions around the phenoxy ring of this scaffold can impart improved potency and selectivity for MEKK2. Analog Compound 1s (16 nM IC₅₀) was further verified by external testing to inhibit MEKK2 and MEKK3 with similar potencies. Compound 1s displayed activity in cell-based assays in which it inhibited ERK5 pathway activation in cells and inhibited cell migration in a scratch assay. Thus, we have identified a scaffold that has promising potential to be developed into a highly selective and potent inhibitor of MEKK2. Information from these SAR studies provides specific guidance for the future design of MEKK2 inhibitor probes.

MiR-17-5p and miR-20a promote chicken cell proliferation at least in part by upregulation of c-Myc via MAP3K2 targeting

The miR-17-92 cluster has been well studied in mammals but less extensively studied in birds. Here, we demonstrated that miR-17-92 cluster overexpression promoted the proliferation of DF1 cells and immortalized chicken preadipocytes (ICPA-1), and miR-17-5p and miR-20a, members of the miR-17-92 cluster, targeted MAP3K2. Further analysis showed that MAP3K2 overexpression reduced the proliferation of DF1 and ICPA-1 cells and attenuated the promotive effect of the miR-17-92 cluster on cell proliferation. Downstream gene expression analysis of the MAPK signalling pathway showed that MAP3K2 overexpression decreased c-Myc expression; in contrast, MAP3K2 knockdown using RNA interference and miR-17-92 cluster overexpression increased c-Myc expression. Furthermore, c-Myc overexpression promoted miR-17-92 cluster expression and DF1 cell proliferation. Taken together, these data indicated that miR-17-92 promotes chicken cell proliferation at least in part by the upregulation of c-Myc via targeting MAP3K2, and the miR-17-92 cluster, c-Myc and E2F1 form a complex regulatory network in chicken cell proliferation.

The long noncoding RNA HULC promotes liver cancer by increasing the expression of the HMGA2 oncogene via sequestration of the microRNA-186

The long noncoding RNA highly up-regulated in liver cancer (HULC) is aberrantly elevated in hepatocellular carcinoma (HCC), and this up-regulation is crucial for HCC pathogenesis. However, the underlying mechanism in HULC up-regulation is poorly understood. We hypothesized that HULC might modulate the oncogene high mobility group A2 (HMGA2) to promote hepatocarcinogenesis. Quantitative real-time PCR analysis showed that the expression levels of HULC were positively correlated with those of HMGA2 in clinical HCC tissues. Interestingly, we also observed that HULC could up-regulate HMGA2 in HCC cells. Mechanistically, we found that the microRNA-186 inhibited HMGA2 expression by targeting the 3'-untranslated region (3'-UTR) of HMGA2 mRNA. Strikingly, HULC acted as a competing noncoding RNA to sequester miR-186 and thereby relieved miR-186-mediated HMGA2 repression. Functionally, HMGA2 knockdown decreased the HULC-enhanced growth of HCC cells both in vitro and in vivo We conclude that the long noncoding RNA HULC increases HMGA2 expression by sequestering miR-186 post-transcriptionally and thereby promotes liver cancer growth, providing new insights into the mechanism by which HULC enhances hepatocarcinogenesis.

Upregulation of miR-520b promotes ovarian cancer growth

Ovarian cancer is the most common gynecological malignant cancer in female genitalia. Dysregulation or dysfunction of microRNAs (miRs) contribute to cancer development. The role of miR-520b in ovarian cancer remains unclear. The present study investigated the role of miR-520b in ovarian cancer and determined that the expression levels of miR-520b in ovarian cancer tissues and cell lines were upregulated. By contrast, reverse transcription-quantitative polymerase chain reaction and immunohistochemistry revealed that the mRNA and protein expression levels of ring finger protein 216 (RNF216) were downregulated in ovarian cancer, indicating that there was a negative correlation between miR-520b and RNF216. In miR-520b-knockdown cells, downregulation of miR-520b reduced cell proliferation, while upregulation of miR-520b promoted cell proliferation. In addition, RNF216 was predicted by TargetScanHuman and was observed to be targeted by miR-520b. In conclusion, the present data indicated that high expression of miR-520b in ovarian cancer promoted cell growth via RNF216.

The Fragment HMGA2-sh-3p20 from HMGA2 mRNA 3'UTR Promotes the Growth of Hepatoma Cells by Upregulating HMGA2

High mobility group A2 (HMGA2) plays a crucial role in the development of cancer. However, the mechanism by which HMGA2 promotes the growth of hepatocellular carcinoma (HCC) remains unclear. Here, we explore the hypothesis that HMGA2 may enhance the growth of hepatoma cells through a fragment based on the secondary structure of HMGA2 mRNA 3′-untranslated region (3′UTR). Bioinformatics analysis showed that HMGA2 mRNA displayed a hairpin structure within its 3′UTR, termed HMGA2-sh. Mechanistically, RNA immunoprecipitation assays showed that the microprocessor Drosha or DGCR8 interacted with HMGA2 mRNA in hepatoma cells. Then, Dicer contributes to the generation of the fragment HMGA2-sh-3p20 from the HMGA2-sh. HMGA2-sh-3p20 was screened by PCR analysis. Interestingly, HMGA2-sh-3p20 increased the expression of HMGA2 through antagonizing the tristetraprolin (TTP)-mediated degradation of HMGA2. HMGA2-sh-3p20 inhibited the expression of PTEN by targeting the 3′UTR of PTEN mRNA. In addition, the overexpression of PTEN could downregulate HMGA2 expression. Significantly, we documented the ability of HMGA2-sh-3p20 to promote the growth of hepatoma cells in vitro and in vivo. Thus, we conclude that the fragment HMGA2-sh-3p20 from HMGA2 mRNA 3′UTR promotes the growth of hepatoma cells by upregulating HMGA2. Our finding provides new insights into the mechanism by which HMGA2 enhances hepatocarcinogenesis.

MiR-520b as a novel molecular target for suppressing stemness phenotype of head-neck cancer by inhibiting CD44

Cancer stem cells preferentially acquire the specific characteristics of stress tolerance and high mobility, allowing them to progress to a therapy-refractive state. To identify a critical molecule to regulate cancer stemness is indispensable to erratically cure cancer. In this study, we identified miR-520b as a novel molecular target to suppress head-neck cancer (HNC) with stemness phenotype. MiR-520b inhibited cellular migration and invasion via the mechanism of epithelial-mesenchymal transition. It also sensitized cells to therapeutic drug and irradiation. Significantly, miR-520b suppressed spheroid cell formation, as well as reduced expressions of multiple stemness regulators (Nestin, Twist, Nanog, Oct4). The CD44 molecule was identified as a direct target of miR-520b, as shown by the reverse correlative expressions, the response to miR-520 modulation, the luciferase reporter assay, and the functional rescue analyses. These cellular results were confirmed by a tumor xenograft mice study. Administration of miR-520b dramatically restrained tumorigenesis and liver colonization. Conversely, miR-520b silencing led to an acceleration of tumor growth. Taken together, our study demonstrated that miR-520b inhibits the malignancy of HNC through regulation of cancer stemness conversion by targeting CD44. MiR-520b may serve as an emerging therapeutic target that may be further developed for the intervention of refractory HNC.

MicroRNA-520b Functions as a Tumor Suppressor in Colorectal Cancer by Inhibiting Defective in Cullin Neddylation 1 Domain Containing 1 (DCUN1D1)

MicroRNAs (miRs), a class of small noncoding RNAs, are important regulators for gene expression through directly binding to the 3′-untranslated region (3′-UTR) of their target mRNA. Recently, downregulation of miR-520b has been observed in several common human cancers. However, the exact role of miR-520b in colorectal cancer (CRC) has not previously been studied. In this study, our data showed that miR-520b was significantly downregulated in CRC and cell lines when compared with adjacent normal tissues and a normal intestinal epithelial cell line. Low expression of miR-520b was notably associated with the malignant progress and a shorter survival time for CRC patients. Restoration of miR-520b inhibited cell proliferation, migration, invasion, and epithelial–mesenchymal transition (EMT) in CRC cells. Defective in cullin neddylation 1 domain containing 1 (DCUN1D1) was then identified as a novel target gene of miR-520b in CRC cells. The expression of DCUN1D1 was significantly increased in CRC, with a negative correlation to miR-520b expression in CRC tissues. Moreover, a high expression of DCUN1D1 was significantly associated with the malignant progress and a poor prognosis for CRC patients. Furthermore, overexpression of DCUN1D1 rescued the miR-520b-mediated malignant phenotypes and EMT in CRC cells. The data demonstrate that miR-520b functions as a tumor suppressor in CRC through targeting DCUN1D1, suggesting that miR-520b may become a potential therapeutic target for the treatment of CRC.

MicroRNA-186 suppresses cell proliferation and metastasis through targeting MAP3K2 in non-small cell lung cancer

MicroRNAs are a class of small endogenous non-coding RNAs that play crucial roles in the initiation and progression of human cancers. miR-186 was found decreased in various human malignancies and function as a tumor suppressor. However, the regulating mechanism of miR-186 in growth and metastasis of human non-small cell lung cancer (NSCLC) is still poorly understood. We investigated the role of miR-186 in the growth and metastasis of human NSCLC. In the present study, we found that miR-186 was significantly decreased in lung cancer tissues and cells. Furthermore, overexpression of miR-186 suppressed lung cancer cell proliferation, migration and invasion, and induced cell apoptosis. Moreover, we found that confirmed mitogen-activated protein kinase kinase kinase 2 (MAP3K2) protein was increased in lung cancer tissues and confirmed that MAP3K2 is a target gene of miR-186. In addition, knockdown of MAP3K2 by RNA interference inhibited lung cancer cell proliferation, migration and invasion, and promoted cell apoptosis in vitro. Furthermore, we observed tthat the overexpression of MAP3K2 partially reversed the inhibitory effect of miR-186 on the proliferation and metastasis of A549 and HCC827 cell lines. Taken together, our data indicated that miR-186 regulates lung cancer growth and metastasis through suppressing MAP3K2 expression, at least partly. Therefore, miR-186-MAP3K2 may represent a new and useful potential clinical treatment and diagnosis target for NSCLC.

Tissue Factor Regulation by miR-520g in Primitive Neuronal Brain Tumor Cells: A Possible Link between Oncomirs and the Vascular Tumor Microenvironment

Pediatric embryonal brain tumors with multilayered rosettes demonstrate a unique oncogenic amplification of the chromosome 19 miRNA cluster, C19MC. Because oncogenic lesions often cause deregulation of vascular effectors, including procoagulant tissue factor (TF), this study explores whether there is a link between C19MC oncogenic miRNAs (oncomirs) and the coagulant properties of cancer cells, a question previously not studied. In a pediatric embryonal brain tumor tissue microarray, we observed an association between C19MC amplification and reduced fibrin content and TF expression, indicative of reduced procoagulant activity. In medulloblastoma cell lines (DAOY and UW228) engineered to express miR-520g, a biologically active constituent of the C19MC cluster, we observed reduced TF expression, procoagulant and TF signaling activities (responses to factor VIIa stimulation), and diminished TF emission as cargo of extracellular vesicles. Antimir and luciferase reporter assays revealed a specific and direct effect of miR-520g on the TF 3' untranslated region. Although the endogenous MIR520G locus is methylated in differentiated cells, exposure of DAOY cells to 5-aza-2'-deoxycytidine or their growth as stem cell-like spheres up-regulated endogenous miR-520g with a coincident reduction in TF expression. We propose that the properties of tumors harboring oncomirs may include unique alterations of the vascular microenvironment, including deregulation of TF, with a possible impact on the biology, therapy, and hemostatic adverse effects of both disease progression and treatment.

Effect of Liuweidihuang pill and Jinkuishenqi pill on inhibition of spontaneous breast carcinoma growth in mice

OBJECTIVE

To investigate the preventing and treating action of Liuweidihuang pill (LP) and Jinkuishenqi pill (JP) on spontaneous breast carcinoma in mice.

METHODS

A model of spontaneous breast carcinoma was derived from 11.5-month-old female Kunming breeding mice following the delivery of several litters. The mice were randomly divided into five groups: model control group (C), Liuweidihuang pill high-dose group (LH; 4.6 g · kg(-1) · d(-1)), Liuweidihuang pill low-dose group (LL; 2.3 g · kg(-1) · d(-1)), Jinkuishenqi pill high-dose group (JH; 4.6 g · kg(-1) · d(-1)) and Jinkuishenqi pill low-dose group (JL; 2.3 g · kg(-1) · d(-1)). Cancer tissue volume was measured by water immersion. Histopathology was analyzed by hematoxylin and eosin staining. Vascular endothelial growth factor (VEGF), extracellular signal-regulated kinase (ERK) and cyclin D1 protein expression in cancer tissue was assayed by western blotting.

RESULTS

Compared with the control group, cancer tissue volume and weight were lower in the LP and JP groups, and survival time was longer. The expression of VEGF, ERK and Cyclin D1 were inhibited in the LP and JP groups (P < 0.05), and cell differentiation was increased. Tumor weights and volumes and VEGF, ERK and Cyclin D1 expression in LL or LH were significantly lower than in JL and JH (P < 0.01).

CONCLUSION

Both LP and JP could restrain cancer growth and promote cancer cell differentiation; moreover, LP was more effective than JP The likely mechanism of action was via inhibition of VEGF, ERK and cyclin D1.

MicroRNAs dysregulation in hepatocellular carcinoma: Insights in genomic medicine

Hepatocellular carcinoma (HCC) is the leading primary liver cancer and its clinical outcome is still poor. MicroRNAs (miRNAs) have demonstrated an interesting potential to regulate gene expression at post-transcriptional level. Current findings suggest that miRNAs deregulation in cancer is caused by genetic and/or epigenetic, transcriptional and post-transcriptional modifications resulting in abnormal expression and hallmarks of malignant transformation: aberrant cell growth, cell death, differentiation, angiogenesis, invasion and metástasis. The important role of miRNAs in the development and progression of HCC has increased the efforts to understand and develop mechanisms of control overt this single-stranded RNAs. Several studies have analyzed tumoral response to the regulation and control of deregulated miRNAs with good results in vitro and in vivo, proving that targeting aberrant expression of miRNAs is a powerful anticancer therapeutic. Identification of up and/or down regulated miRNAs related to HCC has led to the discovery of new potential application for detection of their presence in the affected organism. MiRNAs represent a relevant new target for diagnosis, prognosis and treatment in a wide variety of pathologic entities, including HCC. This manuscript intends to summarize current knowledge regarding miRNAs and their role in HCC development.

Identification of ponatinib and other known kinase inhibitors with potent MEKK2 inhibitory activity

The kinase MEKK2 (MAP3K2) may play an important role in tumor growth and metastasis for several cancer types. Thus, targeting MEKK2 may represent a novel strategy for developing more effective therapies for cancer. In order to identify small molecules with MEKK2 inhibitory activity, we screened a collection of known kinase inhibitors using a high throughput MEKK2 intrinsic ATPase enzyme assay and confirmed activity of the most potent hits with this primary assay. We also confirmed activities of these known kinase inhibitors with an MEKK2 transphosphorylation slot blot assay using MKK6 as a substrate. We observed a good correlation in potencies between the two orthogonal MEKK2 kinase activity assay formats for this set of inhibitors. We report that ponatinib, AT9283, AZD7762, JNJ-7706621, PP121 and hesperadin had potent MEKK2 enzyme inhibitory activities ranging from 4.7 to 60 nM IC50. Ponatinib is an FDA-approved drug that potently inhibited MEKK2 enzyme activity with IC50 values of 10-16 nM. AT9283 is currently in clinical trials and produced MEKK2 IC50 values of 4.7-18 nM. This set of known kinase inhibitors represents some of the most potent in vitro MEKK2 inhibitors reported to date and may be useful as research tools. Although these compounds are not selective for MEKK2, the structures of these compounds give insight into pharmacophores that potently inhibit MEKK2 and could be used as initial leads to design highly selective inhibitors of MEKK2.

MiR-520b suppresses proliferation of hepatoma cells through targeting ten-eleven translocation 1 (TET1) mRNA

Accumulating evidence indicates that microRNAs are able to act as oncogenes or tumor suppressor genes in human cancer. We previously reported that miR-520b was down-regulated in hepatocellular carcinoma (HCC) and its deregulation was involved in hepatocarcinogenesis. In the present study, we report that miR-520b suppresses cell proliferation in HCC through targeting the ten-eleven translocation 1 (TET1) mRNA. Notably, we identified that miR-520b was able to target 3'-untranslated region (3'UTR) of TET1 mRNA by luciferase reporter gene assays. Then, we revealed that miR-520b was able to reduce the expression of TET1 at the levels of mRNA and protein using reverse transcription-polymerase chain reaction and Western blotting analysis. In terms of function, 5-ethynyl-2-deoxyuridine (EdU) incorporation and colony formation assays demonstrated that the forced miR-520b expression remarkably inhibited proliferation of hepatoma cells, but TET1 overexpression could rescue the inhibition of cell proliferation mediated by miR-520b. Furthermore, anti-miR-520b enhanced proliferation of hepatoma cells, whereas silencing of TET1 abolished anti-miR-520b-induced acceleration of cell proliferation. Then, we validated that the expression levels of miR-520b were negatively related to those of TET1 mRNA in clinical HCC tissues. Thus, we conclude that miR-520b depresses proliferation of liver cancer cells through targeting 3'UTR of TET1 mRNA. Our finding provides new insights into the mechanism of hepatocarcinogenesis.

SP1-mediated microRNA-520d-5p suppresses tumor growth and metastasis in colorectal cancer by targeting CTHRC1

Recent evidence suggests that miR-520 family has an important role in regulating tumorigenesis and development of various types of solid cancers. However, as one of the most common cancers in the world, there is little known about the underlying regulatory mechanisms of miR-520 in colorectal cancer (CRC). In the present study, we investigated the expression of microRNA-520d-5p (miR-520d-5p) in CRC specimens and then explored its potential role and mechanism in CRC progression. We found that miR-520d-5p was markedly down-regulated in CRC clinical specimens compared with adjacent normal tissues by real-time PCR. Dual-luciferase assays confirmed that miR-520d-5p directly targeting CTHRC1 and SP1 transactivate miR-520d-5p by binding to its upstream promoter region. The biological functional experiments showed that ectopic re-expression of miR-520d-5p suppressed CRC cell proliferation, migration and invasion, whereas the inhibition of miR-520d-5p displayed an inverse effect in vitro and in vivo. Western blot shown that miR-520d-5p abrogated the epithelial-mesenchymal transition by inactivating the phosphorylation of Erk1/2. In conclusion, our findings indicate that miR-520d-5p is significantly down-expressed and involved in CRC progression and metastasis by targeting CTHRC1 and regulated by SP1, which provide new support for miR-520d-5p maybe as a novel anti-onco molecular target for the treatment of CRC in the future.

Role of non-coding RNAs in development and progression of hepatocellular carcinoma

Non-coding RNAs (ncRNAs) refer to all RNAs without protein encoding function due to the lack of an open reading frame, and they are often transcribed from the complementary strand of protein encoding genes. Based on the length, ncRNAs can be divided into long ncRNAs (lncRNAs) and short ncRNAs, and short ncRNAs include microRNAs, piRNAs and so on. ncRNAs are not only involved in life activities but also closely related to tumor cell differentiation, proliferation, migration, invasion and infiltration. ncRNAs play an important role in the development of cancer. Hepatocellular carcinoma is a digestive cancer with high incidence and mortality rates, posing a serious threat to human health; however, its pathogenesis is still unclear. In recent years, a large number of studies have found that changes in the expression of ncRNAs have a pivotal role in the development of hepatocellular carcinoma. This review summarizes the current state of knowledge about the association between ncRNAs sand hepatocellular carcinoma, with an aim to provide some clues to its diagnosis and treatment.

The microRNA-520a-3p inhibits proliferation, apoptosis and metastasis by targeting MAP3K2 in non-small cell lung cancer

Growing evidence indicates that miR-520a was involved in the complement attack and migration of tumor cells, but nonetheless, the role of miR-520a-3p in non-small cell lung cancer (NSCLC) is not clear. Mitogen-activated protein kinase kinase kinase 2 (MAP3K2) is a kinase belonging to the serine/threonine protein kinase family. To develop potential therapy targeting MAP3K2, we studied the roles of miR-520a-3p in the proliferation, apoptosis and metastasis of NSCLC. The expression levels of miR-520a-3p were quantified in tumor tissues of NSCLC by qRT-PCR, and the mimics and inhibitors were used to verify the function of miR-520a-3p. The cell proliferation was evaluated by MTT assay, and the migration and invasion was evaluated by transwell assay. The athymic mice subcutaneous injection was used to research NSCLC cell tumor formation. The bioinformatics tools and luciferase assay was applied to detect the relationship between miR-520a-3p and its target. Protein levels of miR-520a-3p target was determined by western blot analysis. MiR-520a-3p expression was decreased in the NSCLC tissues compared with their normal counterparts and lower expression of miR-520a-3p in NSCLC tissues was associated with a higher clinical stage, NSCLC metastasis and poor prognosis. Inhibition of expression of miR-520a-3p can reduce in vitro NSCLC cell migration and invasion as well as in vivo metastasis. MAP3K2 mRNA contains a binding site for miR-520a-3p in the 3'UTR. MAP3K2 is one of target of miR-520a-3p. Together, our data demonstrated that miR-520a-3p inhibits proliferation, apoptosis and metastasis in NSCLC by targeting MAP3K2, and miR-520a-3p may be used as a prognosis marker for NSCLC in clinical research.

miRNA in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide. Despite improvements in HCC therapy, the prognosis for HCC patients remains poor due to a high incidence of recurrence. An improved understanding of the pathogenesis of HCC development would facilitate the development of more effective outcomes for the diagnosis and treatment of HCC at earlier stages. miRNA are small, endogenous, non-coding, ssRNA that are 21-30 nucleotides in length and modulate the expression of various target genes at the post-transcriptional and translational levels. Aberrant expression of miRNA is common in various human malignancies and modulates cancer-associated genomic regions or fragile sites. As for the relationship between miRNA and HCC, several studies have demonstrated that the aberrant expression of specific miRNA can be detected in HCC cells and tissues. However, little is known about the mechanisms of miRNA-related cell proliferation and development. In this review, we summarize the central and potential roles of miRNA in the pathogenesis of HCC and elucidate new possibilities that may be useful as diagnostic and prognostic markers, as well as novel therapeutic targets in HCC.

The role of microRNAs in the control of innate immune response in cancer

Ligands for receptors of natural killer (NK) cells and CD8(+) cytotoxic T lymphocytes (CTL), such as the inhibitory nonclassical HLA-G, the activating stress-induced major histocompatibility complex class I-related antigens MICA and MICB, and/or the UL16-binding proteins (ULBPs), are often aberrantly expressed upon viral infection and neoplastic transformation, thereby preventing virus-infected or malignant-transformed cells from elimination by immune effector cells. Recently, it has been shown that ligands of both NK and CD8(+) T cells are regulated by a number of cellular and/or viral microRNAs (miRs). These miRs are involved in shaping the antiviral and/or antitumoral immune responses as well as neoplastic growth properties. This review summarizes the expression pattern and function of miRs directed against selected NK and T cell receptor ligands, their putative role in shaping immune surveillance and tumorigenicity, and their clinical relevance. In addition, the potential role of RNA-binding proteins in the post-transcriptional gene regulation of these ligands will be discussed.

The role of noncoding RNA in hepatocellular carcinoma

Increasing noncoding RNAs (ncRNAs) were found to show abnormal expression patterns in various human cancers. Based on their length, ncRNAs are briefly divided into two categories. Transcripts that are shorter than 200 nucleotides are recognized as short/small noncoding RNAs and greater than 200 nucleotides as long noncoding RNAs (lncRNAs). Short/small noncoding RNAs include microRNAs, piRNAs, snoRNAs, and endogenous siRNAs. Numerous studies have revealed that these short/small ncRNA play important roles in multiple biological processes and tumorigenesis. In contrast to small ncRNAs, long noncoding RNAs are much less known concerning their functions in human cancers especially in hepatocellular carcinoma (HCC). In this review, we highlight recent progress regarding HCC development, tumorigenesis, metastasis, clinical implication, as well as the role in the risk of HBV infection.

Hepatitis B virus X protein accelerates hepatocarcinogenesis with partner survivin through modulating miR-520b and HBXIP

BACKGROUND

Hepatitis B virus X protein (HBx) plays crucial roles in hepatocarcinogenesis. However, the underlying mechanism remains elusive. We have reported that HBx is able to up-regulate survivin in hepatocellular carcinoma tissues. The oncopreotein hepatitis B X-interacting protein (HBXIP), a target of miR-520b, is involved in the development of cancer. In this study, we focus on the investigation of hepatocarcinogenesis mediated by HBx.

METHODS

The expression of HBx and survivin was examined in the liver tissues of HBx-Tg mice. The effect of HBx/survivin on the growth of LO2-X-S cells was determined by colony formation and transplantation in nude mice. The effect of HBx/survivin on promoter of miR-520b was determined by Western blot analysis, luciferase reporter gene assay, co-immunoprecipitation (co-IP) and chromatin immunoprecipitation (ChIP), respectively. The expression of HBx, survivin and HBXIP was detected by immunohistochemistry and real-time PCR in clinical HCC tissues, respectively. The DNA demethylation of HBXIP promoter was examined. The functional influence of miR-520b and HBXIP on proliferation of hepatoma cells was analyzed by MTT, colony formation, EdU and transplantation in nude mice in vitro and in vivo.

RESULTS

In this study, we provided evidence that HBx up-regulated survivin in the liver cancer tissues of HBx-Tg mice aged 18 M. The engineered LO2 cell lines with survivin and/or HBx were successfully established, termed LO2-X-S. MiR-520b was down-regulated in LO2-X-S cells and clinical HCC tissues. Our data revealed that HBx survivin-dependently down-regulated miR-520b through interacting with Sp1 in the cells. HBXIP was highly expressed in LO2-X-S cells, liver cancer tissues of HBx-Tg mice aged 18 M and clinical HCC tissues (75.17%, 112/149). The expression level of HBXIP was positively associated with those of HBx or survivin in clinical HCC tissues. In addition, we showed that HBx survivin-dependently up-regulated HBXIP through inducing demethylation of HBXIP promoter in LO2-X-S cells and clinical HCC tissues. In function, low level miR-520b and high level HBXIP mediated by HBx with partner survivin contributed to the growth of LO2-X-S cells in vitro and in vivo.

CONCLUSION

HBx accelerates hepatocarcinogenesis with partner survivin through modulating tumor suppressor miR-520b and oncoprotein HBXIP.

MicroRNAs in hepatocellular carcinoma: carcinogenesis, progression, and therapeutic target

Hepatocellular carcinoma (HCC) is the third leading cause of death from cancer, with dismal outcomes and an increasing incidence worldwide. Hepatocarcinogenesis is a multistep process that progresses from chronic hepatitis through cirrhosis and/or dysplastic nodule to HCC. However, the detailed molecular pathogenesis remains unclear. MicroRNAs (miRNAs), small noncoding RNAs that regulate the translation of many genes, have emerged as key factors involved in several biological processes, including development, differentiation, and cell proliferation. Recent studies have uncovered the contribution of miRNAs to the cancer pathogenesis, as they can behave as oncogenes or tumor suppressor genes. In addition, other studies have demonstrated their potential values in the clinical management of HCC patients as some miRNAs may be used as prognostic or diagnostic markers. In this review, we summarize current knowledge about the roles of miRNAs in carcinogenesis and progression of HCC. We also discuss the potential application of miRNAs as diagnostic biomarkers and their potential roles in the intervention of HCC.

The pro-proliferative effects of nicotine and its underlying mechanism on rat airway smooth muscle cells

Recent studies have shown that nicotine, a major component of cigarette smoke, can stimulate the proliferation of non-neuronal cells. Cigarette smoking can promote a variety of pulmonary and cardiovascular diseases, such as chronic obstructive pulmonary disease (COPD), atherosclerosis, and cancer. A predominant feature of COPD is airway remodeling, which includes increased airway smooth muscle (ASM) mass. The mechanisms underlying ASM remodeling in COPD have not yet been fully elucidated. Here, we show that nicotine induces a profound and time-dependent increase in DNA synthesis in rat airway smooth muscle cells (RASMCs) in vitro. Nicotine also significantly increased the number of RASMCs, which was associated with the increased expression of Cyclin D1, phosphorylation of the retinoblastoma protein (RB) and was dependent on the activation of Akt. The activation of Akt by nicotine occurred within minutes and depended upon the nicotinic acetylcholine receptors (nAchRs). Activated Akt increased the phosphorylation of downstream substrates such as GSK3β. Our data suggest that the binding of nicotine to the nAchRs on RASMCs can regulate cellular proliferation by activating the Akt pathway.

MicroRNA-206 induces G1 arrest in melanoma by inhibition of CDK4 and Cyclin D

Expression profiling of microRNAs in melanoma lesional skin biopsies compared with normal donor skin biopsies, as well as melanoma cell lines compared with normal melanocytes, revealed that hsa-miR-206 was down-regulated in melanoma (-75.4-fold, P = 1.7 × 10(-4)). MiR-206 has been implicated in a large number of cancers, including breast, lung, colorectal, ovarian, and prostate cancers; however, its role in tumor development remains largely unknown, its biologic function is poorly characterized, and its targets affecting cancer cells are largely unknown. MiR-206 reduced growth and migration/invasion of multiple melanoma cell lines. Bioinformatics identified cell cycle genes CDK2, CDK4, Cyclin C, and Cyclin D1 as strong candidate targets. Western blots and 3'UTR reporter gene assays revealed that miR-206 inhibited translation of CDK4, Cyclin D1, and Cyclin C. Additionally, hsa-miR-206 transfection induced G1 arrest in multiple melanoma cell lines. These observations support hsa-miR-206 as a tumor suppressor in melanoma and identify Cyclin C, Cyclin D1, and CDK4 as miR-206 targets.

The Complex Relationship between Liver Cancer and the Cell Cycle: A Story of Multiple Regulations

The liver acts as a hub for metabolic reactions to keep a homeostatic balance during development and growth. The process of liver cancer development, although poorly understood, is related to different etiologic factors like toxins, alcohol, or viral infection. At the molecular level, liver cancer is characterized by a disruption of cell cycle regulation through many molecular mechanisms. In this review, we focus on the mechanisms underlying the lack of regulation of the cell cycle during liver cancer, focusing mainly on hepatocellular carcinoma (HCC). We also provide a brief summary of novel therapies connected to cell cycle regulation.

miR-451 inhibits cell proliferation in human hepatocellular carcinoma through direct suppression of IKK-β

It has been demonstrated that nuclear factor-kappa B (NF-κB), which is overactivated in hepatocellular carcinoma (HCC), plays important roles in the development of HCC. Recently, a group of dysregulated micro RNAs were reported to be involved in HCC progression. Further understanding of micro RNA-mediated regulation of NF-κB pathway may provide novel therapeutic targets for HCC. In this study, we found that miR-451 expression was markedly downregulated in HCC cells and tissues compared with immortalized normal liver epithelial cells and adjacent non- cancerous tissues, respectively. Upregulation of miR-451 inhibited, while downregulation of miR-451 promoted, the tumorigenicity of HCC cells both in vitro and in vivo. These changes in the properties of HCC cells were associated with deregulation of two well-known cellular G1/S transitional regulators, cyclin D1 and c-Myc, which are downstream targets of NF-κB pathway. Furthermore, we demonstrated that miR-451 upregulation led to downregulation of cyclin D1 and c-Myc through inhibition of NF-κB pathway initiated by direct targeting of the IKBKB 3'-untranslated region. Therefore, these results suggest that miR-451 downregulation plays an important role in promoting proliferation of HCC cells and may provide the basis for the development of novel anti-HCC therapies.