miRNA-346 promotes proliferation, migration and invasion in liver cancer

Mechanism insights and therapeutic intervention of tumor metastasis: latest developments and perspectives

Metastasis remains a pivotal characteristic of cancer and is the primary contributor to cancer-associated mortality. Despite its significance, the mechanisms governing metastasis are not fully elucidated. Contemporary findings in the domain of cancer biology have shed light on the molecular aspects of this intricate process. Tumor cells undergoing invasion engage with other cellular entities and proteins en route to their destination. Insights into these engagements have enhanced our comprehension of the principles directing the movement and adaptability of metastatic cells. The tumor microenvironment plays a pivotal role in facilitating the invasion and proliferation of cancer cells by enabling tumor cells to navigate through stromal barriers. Such attributes are influenced by genetic and epigenetic changes occurring in the tumor cells and their surrounding milieu. A profound understanding of the metastatic process's biological mechanisms is indispensable for devising efficacious therapeutic strategies. This review delves into recent developments concerning metastasis-associated genes, important signaling pathways, tumor microenvironment, metabolic processes, peripheral immunity, and mechanical forces and cancer metastasis. In addition, we combine recent advances with a particular emphasis on the prospect of developing effective interventions including the most popular cancer immunotherapies and nanotechnology to combat metastasis. We have also identified the limitations of current research on tumor metastasis, encompassing drug resistance, restricted animal models, inadequate biomarkers and early detection methods, as well as heterogeneity among others. It is anticipated that this comprehensive review will significantly contribute to the advancement of cancer metastasis research.

miR-193b-3p and miR-346 Exert Antihypertensive Effects in the Rostral Ventrolateral Medulla

BACKGROUND

Rostral ventrolateral medulla (RVLM) neuron hyperactivity raises sympathetic outflow, causing hypertension. MicroRNAs (miRNAs) contribute to diverse biological processes, but their influence on RVLM neuronal excitability and blood pressure (BP) remains widely unexplored.

METHODS AND RESULTS

The RVLM miRNA profiles in spontaneously hypertensive rats were unveiled using RNA sequencing. Potential effects of these miRNAs in reducing neuronal excitability and BP and underlying mechanisms were investigated through various experiments. Six hundred thirty-seven miRNAs were identified, and reduced levels of miR-193b-3p and miR-346 were observed in the RVLM of spontaneously hypertensive rats. Increased miR-193b-3p and miR-346 expression in RVLM lowered neuronal excitability, sympathetic outflow, and BP in spontaneously hypertensive rats. In contrast, suppressing miR-193b-3p and miR-346 expression in RVLM increased neuronal excitability, sympathetic outflow, and BP in Wistar Kyoto and Sprague-Dawley rats. Cdc42 guanine nucleotide exchange factor (Arhgef9) was recognized as a target of miR-193b-3p. Overexpressing miR-193b-3p caused an evident decrease in Arhgef9 expression, resulting in the inhibition of neuronal apoptosis. By contrast, its downregulation produced the opposite effects. Importantly, the decrease in neuronal excitability, sympathetic outflow, and BP observed in spontaneously hypertensive rats due to miR-193b-3p overexpression was greatly counteracted by Arhgef9 upregulation.

CONCLUSIONS

miR-193b-3p and miR-346 are newly identified factors in RVLM that hinder hypertension progression, and the miR-193b-3p/Arhgef9/apoptosis pathway presents a potential mechanism, highlighting the potential of targeting miRNAs for hypertension prevention.

Regulatory and therapeutic implications of competing endogenous RNA network in breast cancer progression and metastasis: A review

Breast cancer (BC) is a global health concern, and development of diagnostic tools and targeted treatments for BC remains challenging. Therapeutic approaches for BC often involve a combination of surgery, radiation therapy, chemotherapy, targeted therapy, and hormone therapy. In recent years, there has been a growing interest in the role of noncoding RNAs (ncRNAs), including long ncRNAs (lncRNAs) and microRNAs (miRNAs), in BC and their therapeutic implications. Various biological processes such as cell proliferation, migration, and apoptosis rely on the activities of these ncRNAs, and their dysregulation has been implicated in BC progression. The regulatory function of the competitive endogenous RNA (ceRNA) network, which comprises lncRNAs, miRNAs, and mRNAs, has been the subject of extensive pathophysiological research. Most lncRNAs serve as molecular sponges for miRNAs and sequester their activities, thereby regulating the expression of target mRNAs and contributing to the promotion or inhibition of BC progression. This review summarizes recent findings on the role of ceRNA networks in BC progression, metastasis, and therapeutic resistance, and highlights the association of ceRNA networks with transcription factors and signaling pathways. Understanding the ceRNA network can lead to the discovery of biomarkers and targeted treatment methods to prevent the spread and metastasis of BC.

Targeting non-coding RNAs and N6-methyladenosine modification in hepatocellular carcinoma

Hepatocellular carcinoma (HCC), the most common form of primary liver cancers, accounts for a significant portion of cancer-related death globally. However, the molecular mechanisms driving the onset and progression of HCC are still not fully understood. Emerging evidence has indicated that non-protein-coding regions of genomes could give rise to transcripts, termed non-coding RNA (ncRNA), forming novel functional driving force for aberrant cellular activity. Over the past decades, overwhelming evidence has denoted involvement of a complex array of molecular function of ncRNAs at different stages of HCC tumorigenesis and progression. In this context, several pre-clinical studies have highlighted the potentials of ncRNAs as novel therapeutic modalities in the management of human HCC. Moreover, N6-methyladenosine (m6A) modification, the most prevalent form of internal mRNA modifications in mammalian cells, is essential for the governance of biological processes within cells. Dysregulation of m6A in ncRNAs has been implicated in human carcinogenesis, including HCC. In this review, we will discuss dysregulation of several hallmark ncRNAs (miRNAs, lncRNAs, and circRNAs) in HCC and address the latest advances for their involvement in the onset and progression of HCC. We also focus on dysregulation of m6A modification and various m6A regulators in the etiology of HCC. In the end, we discussed the contemporary preclinical and clinical application of ncRNA-based and m6A-targeted therapies in HCC.

The microRNA target site profile is a novel biomarker in the immunotherapy response

MicroRNAs (miRNAs) bind on the 3' untranslated region (3'UTR) of messenger RNAs (mRNAs) and regulate mRNA expression in physiological and pathological conditions, including cancer. Thus, studies have identified miRNAs as potential biomarkers by correlating the miRNA expression with the expression of important mRNAs and/or clinical outcomes in cancers. However, tumors undergo pervasive 3'UTR shortening/lengthening events through alternative polyadenylation (APA), which varies the number of miRNA target sites in mRNA, raising the number of miRNA target sites (numTS) as another important regulatory axis of the miRNA binding effects. In this study, we developed the first statistical method, BIOMATA-APA, to identify predictive miRNAs based on numTS features. Running BIOMATA-APA on The Cancer Genome Atlas (TCGA) and independent cohort data both with immunotherapy and no immunotherapy, we demonstrated for the first time that the numTS feature 1) distinguishes different cancer types, 2) predicts tumor proliferation and immune infiltration status, 3) explains more variation in the proportion of tumor-infiltrating immune cells, 4) predicts response to immune checkpoint blockade (ICB) therapy, and 5) adds prognostic power beyond clinical and miRNA expression. To the best of our knowledge, this is the first pan-cancer study to systematically demonstrate numTS as a novel type of biomarker representing the miRNA binding effects underlying tumorigenesis and pave the way to incorporate miRNA target sites for miRNA biomarker identification. Another advantage of examining the miRNA binding effect using numTS is that it requires only RNA-Seq data, not miRNAs, thus resulting in high power in the miRNA biomarker identification.

miR-346 regulates the development of ARDS by regulating the function of pulmonary microvascular endothelial cells

In recent years, many studies have reported that microRNAs play an important role in the pathogenesis of a variety of diseases, and the aim of this paper is to explore the role and mechanism of miR-346 in acute respiratory distress syndrome (ARDS). A mouse model of ARDS was constructed by LPS induction, and RT-qPCR assay was used to verify that the expression level of miR-346 in lung tissue was significantly increased, and was negatively correlated with oxygenation index. Inhibiting the expression of miR-346 in mice and HPMECs by miR-346 inhibitor confirmed that decreased miR-346 expression could lead to increased oxygenation index, decreased lung index, lung water content and NO content to reduce lung injury in mice, while lung inflammation was alleviated and apoptosis was reduced in mice. The same results were obtained in cells. BCL6 was predicted to be a target of miR-346 by targetscan and miRDB; when miR-346 was inhibited, BCL6 expression was increased, and if miR-346 and BCL6 expression were inhibited at the same time, it could aggravate lung injury and reduce the proliferation of HPMECs and increase their apoptosis and inflammation in mice. This shows that miR-346 inhibits the migration of HPMECs by regulating BCL6 expression, which in turn promotes the apoptosis of HPMECs, leading to inflammation and inducing ARDS.

miRNAs inspirations in hepatocellular carcinoma: Detrimental and favorable aspects of key performers

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related deaths worldwide. HCC initiation, progression, and therapy failure are all influenced by various variables, including microRNAs (miRNAs). miRNAs are short non-coding RNA sequences that modulate target mRNA expression by deteriorating or repressing translation. miRNAs play an imperative role in HCC pathogenesis by triggering the induction of cancer stem cells (CSCs) and their proliferation, while also delaying apoptosis, sustaining the cell cycle, and inspiring angiogenesis, invasion, and metastasis. Additionally, miRNAs modulate crucial HCC-related molecular pathways such as the p53 pathway, the Wnt/β-catenin pathway, VEGFR2, and PTEN/PI3K/AKT pathway. Consequently, the goal of this review was to give an up-to-date overview of oncogenic and tumor suppressor (TS) miRNAs, as well as their potential significance in HCC pathogenesis and treatment responses, highlighting their underpinning molecular pathways in HCC initiation and progression. Similarly, the biological importance and clinical application of miRNAs in HCC are summarized.

Computing microRNA-gene interaction networks in pan-cancer using miRDriver

DNA copy number aberrated regions in cancer are known to harbor cancer driver genes and the short non-coding RNA molecules, i.e., microRNAs. In this study, we integrated the multi-omics datasets such as copy number aberration, DNA methylation, gene and microRNA expression to identify the signature microRNA-gene associations from frequently aberrated DNA regions across pan-cancer utilizing a LASSO-based regression approach. We studied 7294 patient samples associated with eighteen different cancer types from The Cancer Genome Atlas (TCGA) database and identified several cancer-specific and common microRNA-gene interactions enriched in experimentally validated microRNA-target interactions. We highlighted several oncogenic and tumor suppressor microRNAs that were cancer-specific and common in several cancer types. Our method substantially outperformed the five state-of-art methods in selecting significantly known microRNA-gene interactions in multiple cancer types. Several microRNAs and genes were found to be associated with tumor survival and progression. Selected target genes were found to be significantly enriched in cancer-related pathways, cancer hallmark and Gene Ontology (GO) terms. Furthermore, subtype-specific potential gene signatures were discovered in multiple cancer types.

MiRNA-335 Modulates Hepatoma Cell Lines Apoptosis and Proliferation by Targeting Forkhead Box O3a (FOXO3a)

This study intends to elucidate MiRNA-335’s role in hepatoma cell lines (HCC). Real-time PCR was used to detect MiRNA-335 expression in HCC, flow cytometry and MTT were used to detect apoptosis and proliferation. Luciferase reporting system analyzed the targeting relationship between Foxo3a and MiRNA-335. HCC (SMMC7721 cell) exhibited significantly reduced MiRNA-335 compared to normal hepatocyte cell (HL7702). MiRNA-335 mimic inhibited HCC proliferation and enhanced apoptosis, which were reversed by MiRNA-335 inhibitor. Luciferase reporter gene system showed that MiRNA-335 significantly inhibited the fluorescent activity of Foxo3a 3′-UTR, indicating that MiRNA-335 could target Foxo3a RNA. In conclusion, the decrease of MiRNA-335 can promote the proliferation of hepatoma cells and inhibit apoptosis possibly through regulating Foxo3a, which provides a new direction for the treatment of liver cancer.

MiRNA-136-5p Sensitizes Liver Cancer Cells to Docetaxel by Targeting P53 and Enhances Cell Migration

We aimed to explore whether microRNA (miRNA)-136-5p modulates P53 expression, and affects the efficacy of docetaxel treatment for liver cancer. miRNA array screened the differentially expressed miRNAs in biopsy tissues of liver cancer patients, and the expression of miR-136-5p and P53 in tissues and cells by RT-PCR. Following docetaxel treatment, through increased- and decreased-function method, we detected the impact of the miRNA on cell progression, as well as the sensitivity of docetaxel through MTT assay and colony formation experiment. The correlation between miR-136-5p and P53 was evaluated. The expression of miR-136-5p in liver cancer cells is up-regulated, which is consistent with the results of bioinformatics analysis. Further, miR-136-5p overexpression promoted cell proliferation and migration, and sensitized liver cancer cells to docetaxel. Interestingly, P53 was indicated to bind to miR-136-5p, and P53 participated in the up-regulation of MMP10 induced by miR-136-5p. miR-136-5p enhances the sensitivity to docetaxel in liver cancer and thus could be a biomarker for the treatment against liver cancer.

Progress of HOTAIR-microRNA in hepatocellular carcinoma

The Hox transcript antisense intergenic RNA (HOTAIR) has been identified as a tumor gene, and its expression in HCC is significantly increased. HOTAIR is associated with the proliferation, invasion, metastasis and poor prognosis of HCC. In addition, HOTAIR can also regulate the expression and function of microRNA by recruiting the polycomb repressive complex 2 (PRC2) and competitive adsorption, thus promoting the occurrence and development of HCC. In this review, we discussed the two mechanisms of HOTAIR regulating miRNA through direct binding miRNA and indirect regulation, and emphasized the role of HOTAIR in HCC through miRNA, explained the regulatory pathway of HOTAIR-miRNA-mRNA and introduced the role of this pathway in HCC proliferation, drug resistance, invasion and metastasis.

Oncogenic Role of Exosomal Circular and Long Noncoding RNAs in Gastrointestinal Cancers

Circular RNAs (circRNAs) and long noncoding RNAs (lncRNAs) are differentially expressed in gastrointestinal cancers. These noncoding RNAs (ncRNAs) regulate a variety of cellular activities by physically interacting with microRNAs and proteins and altering their activity. It has also been suggested that exosomes encapsulate circRNAs and lncRNAs in cancer cells. Exosomes are then discharged into the extracellular environment, where they are taken up by other cells. As a result, exosomal ncRNA cargo is critical for cell-cell communication within the cancer microenvironment. Exosomal ncRNAs can regulate a range of events, such as angiogenesis, metastasis, immune evasion, drug resistance, and epithelial-to-mesenchymal transition. To set the groundwork for developing novel therapeutic strategies against gastrointestinal malignancies, a thorough understanding of circRNAs and lncRNAs is required. In this review, we discuss the function and intrinsic features of oncogenic circRNAs and lncRNAs that are enriched within exosomes.

MicroRNA-889-3p restrains the proliferation and epithelial-mesenchymal transformation of lung cancer cells via down-regulation of Homeodomain-interacting protein kinase 1

Dysregulated microRNAs (miRNAs) are common in human cancers and are involved in the proliferation, promotion, and metastasis of tumor cells. Therefore, the aim of this study was to evaluate the expression and biological function of miR-889-3p in lung cancer (LC). MiR-889-3p and Homeodomain-interacting protein kinase 1 (HIPK1) expression was detected in human LC tissues and cells. The correlation of miR-889-3p with the clinicopathology of LC patients was observed. After the transfection of miR-889-3p and HIPK1-related plasmids in human LC cell line A549, several studies were employed for detection of cell growth. In addition, the targeting of miR-889-3p with HIPK1 was verified. The results clarified miR-889-3p was down-regulated, while HIPK1 was up-regulated in LC tissues. Elevated miR-889-3p or repressed HIPK1 weakened the viability, epithelial–mesenchymal transition (EMT), invasion, migration of LC cells, whereas strengthened apoptosis. MiR-889-3p targeted HIPK1; MiR-889-3p mediated HIPK1 to affect the proliferation and EMT of LC cells. Therefore, it is concluded that miR-889-3p repressing HIPK1 restrains the proliferation and EMT of LC cells, providing a novel target for LC therapy.

Research on Mechanism of miRNA-22 Related with Hepatocellular Carcinoma Metastasis for Regulating Process of Tumor Protein P53

The action of miRNA-22 related with HCC metastasis was analyzed in our study and the mechanism of miRNA-22 related with HCC metastasis was discussed. The HCC hep2 cell was transfected with miRNA-22 mimics and miRNA-22 NC instantaneously followed by analysis of cell migration by Transwell assay, cell viability by MTT and clone formation and cell apoptosis by flow cytometry. The action of miRNA-22 mimics and miRNA-22 on the expression of P53 mRNA in HCC Hep2 cell was detected by RT-PCR. The cell activity in miRNA-22 mimics group was significantly elevated compared with miRNA-22 NC group (P < 0.01). Meanwhile, the apoptotic rate, migrated and invaded capacity of HCC cell was significantly elevated (P < 0.01). The expression level of P53 mRNA was reduced (P < 0.01). In conclusion, overexpression of miRNA-22 could restrain the apoptosis of HCC hep2 cell and down-regulated the expression of P53 so as to prompt cell invasion capacity.

Potential biomarker enhancing the activity of tuberculosis, hsa-miR-346

OBJECTIVES

To determine the usefulness of hsa-miR-346, a potential biomarker enhancing the activity of non-tuberculous mycobacterial diseases, as a biomarker of tuberculosis activity.

METHODS

We investigated whether hsa-miR-346 is secreted by human macrophages infected with Mycobacterium tuberculosis (M. tuberculosis) in an in vitro study. In addition, a cross-sectional study was conducted first to evaluate whether serum hsa-miR-346 is elevated in patients with tuberculosis compared with that in healthy individuals. Second, we conducted a retrospective study to evaluate whether anti-tuberculosis treatment reduces serum hsa-miR-346 levels.

RESULTS

Log hsa-miR-346 levels were significantly elevated in the supernatant of human macrophages infected with M. tuberculosis in a dose-dependent manner. The mean serum log hsa-miR-346 levels were -15.48 (-15.76 to -15.21) in patients with tuberculosis and -16.12 (-16.29 to -15.95) in healthy volunteers, which significantly differed. In addition, hsa-miR-346 significantly decreased at 2 months from starting an anti-tuberculosis treatment.

CONCLUSIONS

We consider hsa-miR-346 as a potential biomarker enhancing the tuberculosis activity.

FOSL1 promotes tumorigenesis in colorectal carcinoma by mediating the FBXL2/Wnt/β-catenin axis via Smurf1

Colorectal carcinoma (CC), one of the most prevalent digestive cancers with high mortality and morbidity globally, still lacks powerful therapies to improve the prognosis. Here, we established that the expression of fos-like antigen-1 (Fosl1) was elevated in CC tissues versus adjacent tissues. Importantly, high Fosl1 expression was related to dismal prognosis among CC patients. Functional assays displayed that Fosl1 increased the viability, epithelial-to-mesenchymal transition (EMT), migration and invasion of CC cells. Additionally, a xenograft assay showed that silencing of Fosl1 in CC cells retarded lung, liver and kidney metastases in vivo. Further investigation demonstrated that Fosl1 was involved in malignant aggressiveness of CC cells by binding to smad ubiquitination regulatory factor 1 (Smurf1). Mechanistically, Smurf1-induced F-Box and leucine rich repeat protein 2 (FBXL2) ubiquitination resulted in its degradation, while FBXL2 disrupted the activation of the Wnt/β-catenin signaling. In summary, Fosl1 plays a pro-metastatic and carcinogenetic role in CC, and we provided forceful evidence that Fosl1 inhibition might act as a prognostic and therapeutic option in CC.

XIAP, commonly targeted by tumor suppressive miR-3607-5p and miR-3607-3p, promotes proliferation and inhibits apoptosis in hepatocellular carcinoma

MicroRNAs (miRNAs) are frequently aberrantly expressed in hepatocellular carcinoma (HCC) and are involved in its development. However, their role and mechanism in HCC are still not fully elucidated. Differential expression analysis and survival analysis were performed to identify potential miRNAs in HCC and miR-3607 was identified as a candidate therapeutic target and prognostic biomarker. RT-qPCR confirmed the low expression of mature miR-3607-3p and miR-3607-5p in HCC. Functional experiments suggested that both miR-3607-3p and miR-3607-5p significantly inhibited HCC proliferation and induced apoptosis. Next, the detailed mechanism of miR-3607-3p and miR-3607-5p in HCC was explored by combination of bioinformatic analysis and experimental validation, and uncovered that XIAP, a common target gene of miR-3607-3p and miR-3607-5p, was involoved in their tumor suppressive effects. Finally, a XIAP-associated protein-protein interaction network, consisting of 10 positively correlated genes, was established. Collectively, we for the first time suggest that miR-3607-3p and miR-3607-5p inhibit HCC by acting one common target XIAP.

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.

Oncomir MicroRNA-346 Is Upregulated in Colons of Patients With Primary Sclerosing Cholangitis

INTRODUCTION:

Primary sclerosing cholangitis (PSC) is a cholestatic liver disorder that is frequently associated with ulcerative colitis (UC). Patients with PSC and UC (PSC-UC) have a higher risk of colorectal neoplasia compared with patients with UC. The oncogenic properties of microRNA-346 (miR-346) have been recently reported. We investigated the expression of miR-346 and its 2 target genes, the receptor of vitamin D (VDR), and the tumor necrosis factor-α (TNF-α), which are known to modulate carcinogenesis.

METHODS:

Ascending and sigmoid colon biopsies were obtained from patients with PSC, PSC and UC (PSC-UC), UC, and healthy controls (n = 10 in each group). Expressions of VDR, TNF-α, 18S RNA, p27^Kip1, miR-346, and reference microRNA, miR-191, were evaluated by real-time PCR using human TaqMan Gene Expression and TaqMan MicroRNA Assays. Functional studies with miR-346 mimic and inhibitor were conducted in HepG2 and Caco-2 cells. The effect of ursodeoxycholic acid on miR-346 expression was examined in Caco-2 cells.

RESULTS:

An increased expression of miR-346 in the ascending colon of PSC-UC was observed (P < 0.001 vs all groups). In patients with UC, an exceptionally low colonic expression of miRNA-346 was accompanied by the extensive upregulation of VDR and TNF-α genes. A functional in vitro analysis demonstrated that inhibition of miR-346 resulted in the upregulation of VDR and TNF-α, whereas the induction of miR-346 activity suppressed VDR, TNF-α, and p27^Kip1.

DISCUSSION:

The upregulation of miRNA-346 in the colon of patients with PSC may be responsible for the disturbance of VDR and TNF-α signaling pathway, which could result in an inadequate suppression of neoplasia.

Molecular and Functional Roles of MicroRNAs in the Progression of Hepatocellular Carcinoma-A Review

Liver cancer is the fourth leading cause of cancer deaths globally, of which hepatocellular carcinoma (HCC) is the major subtype. Viral hepatitis B and C infections, alcohol abuse, and metabolic disorders are multiple risk factors for liver cirrhosis and HCC development. Although great therapeutic advances have been made in recent decades, the prognosis for HCC patients remains poor due to late diagnosis, chemotherapy failure, and frequent recurrence. MicroRNAs (miRNAs) are endogenous, non-coding RNAs that regulate various molecular biological phenomena by suppressing the translation of target messenger RNAs (mRNAs). miRNAs, which often become dysregulated in malignancy, control cell proliferation, migration, invasion, and development in HCC by promoting or suppressing tumors. Exploring the detailed mechanisms underlying miRNA-mediated HCC development and progression can likely improve the outcomes of patients with HCC. This review summarizes the molecular and functional roles of miRNAs in the pathogenesis of HCC. Further, it elucidates the utility of miRNAs as novel biomarkers and therapeutic targets.

The Significance of Circular RNA DDX17 in Prostate Cancer

Circular RNA DDX17 (circDDX17) has been demonstrated as a tumor suppressor in colorectal cancer. However, mechanisms underlying circDDX17 effects in cases of prostate cancer (PCa) are not well understood. Thus, herein, we determined measures of circDDX17 expression by use of the TCGA database. Expression of circDDX17 in prostate cancer-afflicted tissue samples was determined by qRT-PCR. Functionally, circDDX17 induced remarkable inhibition of cell colonizing ability, invasion, and epithelial-mesenchymal transition (EMT) progression in vitro. Mechanistically, dual-luciferase reporter assays, RNA immunoprecipitation, and RNA pull-down experiments helped verify interactions between circDDX17 and miR-346. Low expression of circDDX17 occurred in TCGA PCa samples. Furthermore, circDDX17 expression was downregulated significantly in PCa. These results suggested that circDDX17 suppressed PC cell mobility, proliferation, and invasion. Mechanistic experiments indicated that circDDX17 might serve as a ceRNA of miR-346 to relieve repressive effects of miR-346 upon phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP). LHPP expression itself was downregulated in TCGA PCa samples. Overall, our findings indicated that the circDDX17/miR-346/LHPP pathway inhibited the progression of prostate cancer and that circDDX17 may be a new potential therapeutic or diagnostic target for treating and diagnosing prostate cancer. As our study also demonstrated for the first time that LHPP might act as an anticancer gene in prostate cancer, the findings could have wide-ranging implications for the treatment of this affliction.

MicroRNA-100 functions as a tumor suppressor in cervical cancer via downregulating the SATB1 expression and regulating AKT/mTOR signaling pathway and epithelial-to-mesenchymal transition

Cervical cancer (CC) is a common malignant tumor among women worldwide, remaining the fourth most frequent cause of cancer death in women. Currently, microRNA (miRNA) is a prevalent topic in tumor-related research. The present study focused on the mechanisms of miR-100 in CC progression. qRT-PCR analysis revealed that the miR-100 expression was notably decreased in CC tissues. In addition, miR-100 downregulation was confirmed to be significantly related to the malignant clinicopathologic features of CC patients. Furthermore, miR-100 overexpression was also verified to significantly repress CC cell proliferation, migration and invasion abilities through modulating the AKT/mTOR signaling pathway and epithelial-to-mesenchymal transition. Bioinformatics analysis and luciferase reporter assay identified that special AT-rich sequence-binding protein 1 was a functional target for miR-100 in CC cells. Moreover, miR-100 overexpression was found to markedly repress the CC tumor growth in vivo. In conclusion, the above results revealed that miR-100 functioned as a cancer suppressor in CC progression and may provide insights into the novel therapeutic target for CC treatment.

LRP6 is involved in the proliferation, migration and invasion of trophoblast cells via miR‑346

Low‑density lipoprotein receptor‑related protein 6 (LRP6) promotes metastasis in numerous types of cancer; however, its role in trophoblast cells has been less frequently reported. In the present study, the effects of up‑ and downregulation of LRP6 on trophoblast cells were investigated accordingly. The study aimed to develop a therapeutic target for gestational choriocarcinoma. The expression levels of LRP6 in pre‑eclampsia (PE) tissues, trophoblast cell lines and gestational choriocarcinoma cells were determined using reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) assay. Double‑luciferase reporter analysis was conducted to detect the regulatory gene of LRP6. Furthermore, the proliferative, migratory and invasive abilities of trophoblasts and gestational choriocarcinoma cells were determined by CCK‑8, wound healing, and Transwell assays, respectively. The expression levels of the genes and proteins of interest [matrix metalloproteinase (MMP)‑2, MMP‑9, tissue inhibitor of metalloproteinase‑1 (TIMP‑1), and TIMP‑2] associated with tumor cell invasion were measured by performing RT‑qPCR and western blotting, respectively. The National Center for Biotechnology Information database revealed that LRP6 was relatively highly expressed in placental tissues, but was poorly expressed in PE tissues and trophoblast cell lines. The upregulation of LRP6 not only increased the activity, migration and invasion of trophoblast cells, but it also promoted the expression of MMP‑2 and MMP‑9, whereas it inhibited the expression levels of TIMP‑1 and TIMP‑2. Such results followed the opposite trend to those of downregulation of LRP6 in gestational choriocarcinoma cells. Moreover, LRP6 was predicted to be the target gene for microRNA (miR)‑346, which was highly expressed in PE tissues and trophoblast cell lines. The present study also revealed that LRP6 could reverse the effects of miR‑346 on the proliferation, migration and invasion of trophoblast cells. Therefore, considered collectively, the results of the present study have demonstrated that LRP6 is involved in the proliferation, migration and invasion of trophoblast cells via miR‑346, and that LRP6 may serve as a potential target in cancer treatment.

The Potential Role of Selected miRNA in Uveal Melanoma Primary Tumors as Early Biomarkers of Disease Progression

Uveal melanoma (UM) is the most common primary tumor of the eye diagnosed in adults, associated with a high risk of metastasis and thereby, poor prognosis. Among known risk factors for the development of metastatic disease is the loss of BAP1 expression and chromosome 3 monosomy in the primary tumor. However, the expression levels of specific micro RNAs (miRNA) in tumor tissue may also serve as a valuable marker for determining the risk of metastatic disease in patients with primary uveal melanoma. In our study, we analyzed the miRNA expression data of cases selected from The Cancer Genome Atlas study on uveal melanoma, and determined a panel of 15 miRNAs differentially expressed between patients with primary and metastatic disease. Next, 6 miRNAs were validated on a group of 46 tumor samples from primary and metastatic patients. We have shown, that expression of hsa-miR-592, hsa-miR-346, and hsa-miR-1247 was significantly increased, while hsa-miR-506 and hsa-miR-513c were decreased in the tumors of patients with metastatic disease. Hsa-miR-196b expression did not differ between the two subgroups, however, we showed significant correlation with BAP1 expression. Moreover, hsa-miR-592 also showed correlation with monosomy 3 tumors. Gene ontology analysis revealed involvement of those miRNAs with cellular processes mediating the metastatic process. Our results showed that miRNAs play an important role in the deregulation of several oncogenic pathways in UM and can, thereby, promote metastatic spread to distant organs. Moreover, differentially expressed miRNAs may be used as an interesting biomarker for the assessment of metastatic risk in uveal melanoma patients.

Upregulation of miR-552 Predicts Unfavorable Prognosis of Gastric Cancer and Promotes the Proliferation, Migration, and Invasion of Gastric Cancer Cells

BACKGROUND

Accumulating evidence indicates that micro-RNAs play a key role in tumor progression and prognosis. However, the overall biological role and clinical significance of microRNA-552 (miR-552) in the pathogenesis of gastric cancer (GC) remain unclear.

METHODS

miR-552 expression was measured in 122 pairs of cancerous and noncancerous tissues and cell lines by quantitative real-time polymerase chain reaction. The relationship between miR-552 and the clinical parameters of patients was analyzed by the χ2 test; Kaplan-Meier analysis and multivariate Cox regression analysis were used to predict the overall survival time and prognosis of patients with different expression of miR-552. Finally, CCK-8 and Transwell were used to detect the changes in cell proliferation, migration, and invasion ability.

RESULTS

miR-552 was expressed at markedly high levels in GC tissues compared to normal tissues and in some GC cell lines (p < 0.001). The upregulation of miR-552 was significantly associated with tumors with advanced TNM stage (p = 0.026), lymph node metastasis (p = 0.018), intestinal metaplasia (p = 0.044), and genomically stable subtype (p = 0.035). Moreover, GC patients with high miR-552 expression showed shorter overall survival (log-rank test, p = 0.011) than those with low expression. Meanwhile, miR-552 was an independent prognostic factor for GC patients (HR 5.657, 95% CI 1.619-19.761, p = 0.007). Finally, miR-552 overexpression promoted the proliferation, migration, and invasion of GC cells (p < 0.01).

CONCLUSION

Taken together, our results indicate that miR-552, as an oncogene of GC, can promote cell proliferation, migration, and invasion, and miR-552 may be a novel prognostic biomarker for GC.

Influence of miR-101 on proliferation of liver cancer cells through the MAPK/ERK signaling pathway

The expression of miR-101 in carcinoma and para-carcinoma tissues of patients with liver cancer was studied. The carcinoma and para-carcinoma tissues of 67 patients with liver cancer treated in Chinese PLA General Hospital were collected, and the expression of miR-101 in carcinoma and para-carcinoma tissues was detected via reverse transcription-polymerase chain reaction (RT-PCR). The liver cancer HepG2 cell line was transfected with miR-101 mimics. Moreover, the influence of miR-101 overexpression on the proliferation of liver cancer cells was detected via Cell Counting Kit-8 assay and colony formation assay. The proportion of Ki67-positive cells in the control group (NC group) and miR-101 overexpression group (miR-101 mimics group) was detected via Ki67 staining. The proportions of cells were detected via flow cytometry, and the predicted target gene Zeste2 enhancer (EZH2) was further verified via luciferase reporter gene assay and western blotting. The miR-101 overexpression significantly inhibited the colony formation and proliferation ability of liver cancer cells (P<0.05). The proportion of Ki67-positive cells in liver cancer cells was lower in miR-101 mimics group (P<0.05). The proportion of cells in G0/G1 phase was increased in miR-101 mimics group compared with that in NC group (P<0.05). The extracellular signal-regulated kinase (ERK)1/2 phosphorylation level in liver cancer cells was obviously suppressed in miR-101 mimics group (P<0.05). Therefore, the expression level of miR-101 declines in liver cancer tissues, and the miR-101 overexpression can inhibit the proliferation of liver cancer cells. The inhibitory effect of miR-101 on the proliferation of liver cancer cells may be related to its inhibition on the mitogen-activated protein kinase (MAPK)/ERK signaling pathway, and the inhibition on the MAPK/ERK may be mediated by the targeted inhibition of miR-101 on EZH2.

Circulating microRNA-301 as a promising diagnostic biomarker of hepatitis C virus-related hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a serious consequence of persistent hepatitis C virus (HCV) infection and represents one of the most aggressive neoplasms globally. The implication of microRNA-301 (miR-301) in the initiation and progression of different types of cancers has been proved. We aimed to assess circulating microRNA-301 as possible biomarker for the early detection of HCC in patients with chronic HCV infection. miR-301 expression levels were estimated in plasma samples of 42 patients with newly diagnosed HCV-related HCC, 48 chronically HCV infected patients with liver cirrhosis and 40 healthy individuals by reverse transcription-quantitative polymerase chain reaction technique. In comparison with chronically HCV infected patients and healthy controls, miR-301 expression levels were significantly increased in HCC patients (P < 0.001). miR-301 levels distinguished HCC patients from chronic HCV patients, with area under the receiver-operating characteristic curve of 0.89 (95% CI 0.82-0.96), the sensitivity and the specificity were 78.57% and 89.58% respectively. Moreover, miR-301 levels were significantly linked with tumor size (P = 0.014), serum levels of alpha-fetoprotein (AFP) (P = 0.028) and Barcelona Clinic Liver Cancer (BCLC) score (P = 0.003). These results reveal that miR-301 can serve as a promising non-invasive biomarker for diagnosis of HCC in chronically HCV infected patients.

Identification of potential miRNA-mRNA regulatory network contributing to pathogenesis of HBV-related HCC

BACKGROUND

Hepatitis B virus (HBV) is one of the major risk factors of hepatocellular carcinoma (HCC). Increasing evidence indicates that microRNA (miRNA)-mRNA axis is involved in HCC. However, a comprehensive miRNA-mRNA regulatory network in HBV-related HCC is still absent. This study aims to identify potential miRNA-mRNA regulatory pathways contributing to pathogenesis of HBV-related HCC.

METHODS

Microarray GSE69580 was downloaded from Gene Expression Omnibus (GEO) database. GEO2R and 'R-limma' were used to conduct differential expression analysis. The common miRNAs appeared in the two analytic sets were screened as potential differentially expressed miRNAs (DE-miRNAs). The prognostic roles of screened DE-miRNAs in HCC were further evaluated using Kaplan-Meier plotter database. Target genes of DE-miRNAs were predicted by miRNet. Then, protein-protein interaction (PPI) networks were established for these targets via the STRING database, after which hub genes in the networks were identified by Cytoscape. Functional annotation and pathway enrichment analyses for the target genes were performed through DAVID database. Three enriched pathways related to HBV-related HCC were selected for further analysis and potential target genes commonly appeared in all three pathways were screened. Cytoscape was employed to construct miRNA-hub gene network. The expression and correlation of potential miRNAs and targets were further detected in clinical HBV-related HCC samples by qRT-PCR.

RESULTS

7 upregulated and 9 downregulated DE-miRNAs were accessed. 5 of 7 upregulated DE-miRNAs and 5 of 7 downregulated DE-miRNAs indicated significant prognostic roles in HCC. 2312 and 1175 target genes were predicted for the upregulated and downregulated DE-miRNAs, respectively. TP53 was identified as the hub gene in the PPI networks. Pathway enrichment analysis suggested that these predicted targets were linked to hepatitis B, pathways in cancer, microRNAs in cancer and viral carcinogenesis. Further analysis of these pathways screened 20 and 16 target genes for upregulated and downregulated DE-miRNAs, respectively. By detecting the expression of 36 target genes, six candidate target genes were identified. Finally, a potential miRNA-mRNA regulatory network was established based on the results of qRT-PCR and expression correlation analysis.

CONCLUSIONS

In the study, potential miRNA-mRNA regulatory pathways were identified, exploring the underlying pathogenesis and effective therapy strategy of HBV-related HCC.

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

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

LncRNA DGCR5 represses the development of hepatocellular carcinoma by targeting the miR-346/KLF14 axis

Long non-coding RNAs (lncRNAs) are a class of regulatory noncoding RNAs. Emerging evidence highlights the critical roles of lncRNAs in the progression of hepatocellular carcinoma (HCC). Although many lncRNAs have been identified in the development of HCC, the association between DiGeorge syndrome critical region gene 5 (DGCR5) and HCC remains unclear. In the current study, we focused on the biological role of DGCR5 in HCC. We observed that DGCR5 was decreased in HCC cells, including SMCC7721, Hep3B, HepG2, MHCC-97L, MHCC-97H, and SNU449 hepatocellular carcinoma cells, compared with the normal human liver cell line THLE-3 normal human liver cells. In addition, DGCR5 overexpression could repress HCC cell growth, migration, and invasion considerably. Increasing studies have indicated the interactions between lncRNAs and microRNAs. MicroRNAs are endogenous small noncoding RNAs and they can play important roles in tumorigenesis. MicroRNA 346 (miR-346) has been demonstrated in various human cancer types, including HCC. MiR-346 was found to be increased in HCC cells and DGCR5 can act as a sponge of miR-346 to modulate the progression of HCC. The binding correlation between DGCR5 and miR-346 was validated in our research. Subsequently, Krüppel-like factor 14 (KLF14) was predicted as a downstream target of miR-346 and miR-346 can induce the development of HCC by inhibiting KLF14. Finally, we proved that DGCR5 can rescue the inhibited levels of KLF14 repressed by miR-346 mimics in MHCC-97H and Hep3B cells. Taken together, it was indicated in our study that DGCR5 can restrain the progression of HCC through sponging miR-346 and modulating KLF14 in vitro.

The Role of MicroRNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common cancers, leading to the second cancer-related death in the global. Although the treatment of HCC has greatly improved over the past few decades, the survival rate of patients is still quite low. Thus, it is urgent to explore new therapies, especially seek for more accurate biomarkers for early diagnosis, treatment and prognosis in HCC. MicroRNAs (miRNAs), small noncoding RNAs, are pivotal participants and regulators in the development and progression of HCC. Great progress has been made in the studies of miRNAs in HCC. The key regulatory mechanisms of miRNAs include proliferation, apoptosis, invasion, metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, drug resistance and autophagy in HCC. And exosomal miRNAs also play important roles in proliferation, invasion, metastasis, and drug resistance in HCC by regulating gene expression in the target cells. In addition, some miRNAs, including exosomal miRNAs, can be as potential diagnostic and prediction markers in HCC. This review summarizes the latest researches development of miRNAs in HCC in recent years.

MicroRNA-23a/27a/24-2 cluster promotes gastric cancer cell proliferation synergistically

Previous studies have indicated that certain microRNAs (miRNAs/miRs) function as either tumor suppressors or oncogenes in human cancer. The present study identified the miR-23a/27a/24-2 cluster, containing miR-23, miR-27a and miR-24, as an oncogene in gastric cancer. The expression of the miR-23a/27a/24-2 cluster was upregulated in clinical gastric cancer tissues. Transfection with inhibitors of miR-23a, miR-27a, or miR-24, either independently or together, repressed in vitro colony formation and in vivo tumor formation. The miR23a/27a/24-2 cluster inhibitors repressed the growth of gastric cancer cells in a synergistic manner. In addition, treatment with lower doses of the miRNA inhibitor mixture induced the formation of apoptotic bodies. According to computational predictions using TargetScan, suppressor of cytokine-induced signaling 6 (SOCS6) was identified as one of the downstream target genes of the miR-23a/27a/24-2 cluster. The expression of SOCS6 was significantly lower in tumor tissues than in matched normal tissues (P<0.01) and was associated with poor survival (P<0.00001). Taken together, these results strongly suggested that the miR-23a/27a/24-2 cluster may mediate the progression of gastric cancer through the suppression of SOCS6 expression. The present study also provides a novel molecular target for the development of an anti-gastric cancer agent.