miR-31 promotes oncogenesis in intrahepatic cholangiocarcinoma cells via the direct suppression of RASA1

Differentially expressed non-coding RNAs and their regulatory networks in liver cancer

The vast majority of human transcriptome is represented by various types of small RNAs with little or no protein-coding capability referred to as non-coding RNAs (ncRNAs). Functional ncRNAs include microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), which are expressed at very low, but stable and reproducible levels in a variety of cell types. ncRNAs regulate gene expression due to miRNA capability of complementary base pairing with mRNAs, whereas lncRNAs and circRNAs can sponge miRNAs off their target mRNAs to act as competitive endogenous RNAs (ceRNAs). Each miRNA can target multiple mRNAs and a single mRNA can interact with several miRNAs, thereby creating miRNA-mRNA, lncRNA-miRNA-mRNA, and circRNA-miRNA-mRNA regulatory networks. Over the past few years, a variety of differentially expressed miRNAs, lncRNAs, and circRNAs (DEMs, DELs, and DECs, respectively) have been linked to cancer pathogenesis. They can exert both oncogenic and tumor suppressor roles. In this review, we discuss the recent advancements in uncovering the roles of DEMs, DELs, and DECs and their networks in aberrant cell signaling, cell cycle, transcription, angiogenesis, and apoptosis, as well as tumor microenvironment remodeling and metabolic reprogramming during hepatocarcinogenesis. We highlight the potential and challenges in the use of differentially expressed ncRNAs as biomarkers for liver cancer diagnosis and prognosis.

Small but mighty: How microRNAs drive the deadly progression of cholangiocarcinoma

Cholangiocarcinoma, also referred to as CCA, is a highly complex epithelial malignancy that can impact various organs and regions of the body, including the perihilar, intrahepatic, and distal organs. This cancer is characterized by the malignant growth of the epithelial lining in the bile ducts, which spans the entire biliary tree and is accountable for disease progression. The current state of affairs concerning CCA is concerning, with poor prognoses, high recurrence rates, and dismal long-term survival rates significantly burden healthcare facilities worldwide. Studies have identified numerous signaling pathways and molecules involved in the development and progression of CCA, including microRNAs, an important class of non-coding RNAs that have the ability to modulate these cellular signaling pathways significantly. In addition, microRNAs may serve as an innovative target for developing novel therapeutic approaches for CCA. In this review, we explore the underlying mechanisms and signaling pathways implicated in the initiation and progression of CCA, focusing on the future direction of utilizing microRNAs as a promising treatment option for this challenging malignancy.

Clinical impact of bile-derived exosomal microRNAs as novel diagnostic and prognostic biomarkers for biliary tract cancers

Sampling of bile juice during endoscopic retrograde cholangiopancreatography (ERCP) has potential benefit of being amenable to the identification of novel biomarkers in liquid biopsy. This study reports the results of a global investigation of exosomal microRNAs (miRNAs) in bile to identify potential biomarkers for biliary tract cancers (BTCs). Eighty-eight bile samples collected during ERCP (45 BTC and 43 noncancer control samples) were enrolled in this study. Eleven BTC samples and nine control samples were assigned as the discovery set. Exosomes in bile and serum samples were collected using a glass membrane column with size-controlled macroporous glass (MPG), and exosomal miRNA expression profiles were evaluated using comprehensive miRNA microarray analysis (3D-Gene). For validation, exosomal miRNA in the bile samples of 34 BTCs and 34 controls were comprehensively evaluated using 3D-Gene. In the discovery set, eight exosomal miRNAs in bile were identified as significant aberrant expression markers, while no miRNA with aberrant expression in serum was identified. In a comparison of the discovery and validation sets, miR-451a and miR-3619-3p were identified as reproducible upregulated markers, and the combination of the two bile miRNAs showed an excellent area under the curve (0.819) value for diagnosing BTCs. In addition, high miR-3619-3p expression in bile reflects poorer prognosis of BTCs (hazard ratio = 2.89). The MPG-extracted exosomal miRNAs in bile aspirated during ERCP provide a convenient new approach for diagnosing biliary diseases. Bile-derived miRNA analysis with miR-451a and miR-3619-3p represents a potentially valuable diagnostic strategy for identifying BTCs as well as a predictive indicator of BTC prognosis.

Analysis of MicroRNA in Bile Cytologic Samples Is Useful for Detection and Diagnosis of Extrahepatic Cholangiocarcinoma

OBJECTIVES

This study aimed to develop reliable biomarkers that improve the ability of bile cytology to diagnose cholangiocarcinoma vs benign biliary lesions.

METHODS

Many studies indicate that microRNAs (miRNAs) are potential candidates for the early diagnosis of cancer. We analyzed the expression of five tumor-associated miRNAs (miR-31-5p, miR-122-5p, miR-378d, miR-182-5p, and miR-92a-3p) in cytology samples using quantitative reverse transcription polymerase chain reaction. We collected 52 surgically resected tissue samples, 84 cytologic specimens from smears (53 cases of cancer and 31 cases of noncancer), and 40 residual sediments after smearing for routine cytology at Hiroshima University Hospital.

RESULTS

The expression of miR-31-5p, miR-378d, and miR-122-5p was significantly higher in cancer tissues than those in normal tissues, while miR-182-5p expression was lower. The expression of miR-31-5p, miR-378d, miR-182-5p, and miR-92a-3p was significantly higher in detached cell samples from smears of cholangiocarcinoma cases than in those from noncancer cases.

CONCLUSIONS

These results suggest that the analysis of miRNAs in bile cytologic specimens is a promising auxiliary tool for distinguishing cholangiocarcinoma from benign biliary lesions.

The Role of microRNAs in Cholangiocarcinoma

Cholangiocarcinoma (CCA), an aggressive malignancy, is typically diagnosed at an advanced stage. It is associated with dismal 5-year postoperative survival rates, generating an urgent need for prognostic and diagnostic biomarkers. MicroRNAs (miRNAs) are a class of non-coding RNAs that are associated with cancer regulation, including modulation of cell cycle progression, apoptosis, metastasis, angiogenesis, autophagy, therapy resistance, and epithelial–mesenchymal transition. Several miRNAs have been found to be dysregulated in CCA and are associated with CCA-related risk factors. Accumulating studies have indicated that the expression of altered miRNAs could act as oncogenic or suppressor miRNAs in the development and progression of CCA and contribute to clinical diagnosis and prognosis prediction as potential biomarkers. Furthermore, miRNAs and their target genes also contribute to targeted therapy development and aid in the determination of drug resistance mechanisms. This review aims to summarize the roles of miRNAs in the pathogenesis of CCA, their potential use as biomarkers of diagnosis and prognosis, and their utilization as novel therapeutic targets in CCA.

CircMTO1 inhibits ox-LDL-stimulated vascular smooth muscle cell proliferation and migration via regulating the miR-182-5p/RASA1 axis

BACKGROUND

Circular RNAs (circRNAs) play critical roles in the development of atherosclerosis (AS). This study investigated the role of circMTO1 in the progression of AS.

METHODS

Serum samples from AS patients and healthy volunteers and vascular smooth muscle cells (VSMCs) were used as the study materials. The expressions of circMTO1 and miR-182-5p were measured by RT-qPCR. The effects of circMTO1, miR-182-5p, and RASA1 on VSMC proliferation and apoptosis were examined by MTT and BrdU assays and wound healing and flow cytometric analyses, respectively. Downstream target genes of circMTO1 and miR-182-5p were predicted using target gene prediction and screening and confirmed using a luciferase reporter assay. RASA1 expression was detected by RT-qPCR and Western blot.

RESULTS

circMTO1 expression was decreased, while miR-182-5p expression was increased in human AS sera and oxidized low-density lipoprotein (ox-LDL)-stimulated VSMCs. CircMTO1 overexpression inhibited the proliferation and promoted the apoptosis of ox-LDL-stimulated VSMCs. CircMTO1 was found to be served as a sponge of miR-182-5p and RASA1 as a target of miR-182-5p. Moreover, circMTO1 acted as a ceRNA of miR-182-5p to enhance RASA1 expression. Furthermore, miR-182-5p overexpression and RASA1 knockdown reversed the effects of circMTO1 overexpression on the proliferation, migration, and apoptosis of ox-LDL-stimulated VSMCs.

CONCLUSION

CircMTO1 inhibited the proliferation and promoted the apoptosis of ox-LDL-stimulated VSMCs by regulating miR-182-5p/RASA1 axis. These results suggest that circMTO1 has potential in AS treatment.

miR-31-5p promotes proliferation and inhibits apoptosis of goat hair follicle stem cells by targeting RASA1/MAP3K1 pathway

The Yangtze River Delta white goat is a sole goat species that can naturally produce superior-quality brush hair. It's worth to mention that study the developmental mechanism of goat hair follicle stem cells is vital for future breed preservation and molecular breeding. In this study, we successfully isolated hair follicle stem cells from the skin tissue of fetal sheep neck spine, and harvested superior-quality and normal-quality brush hair goat tissue. The expression of miR-31-5p in goat hair follicle stem cells was verified by qPCR and Western blot. The effects of overexpression or inhibition of miR-31-5p on the proliferation and apoptosis of hair follicle stem cells were detected by EdU, CCK-8, flow cytometry, etc. miR-31-5p can significantly improve cell proliferation and inhibit cell apoptosis by targeting RASA1 and upregulating MAP3K1 level, whereas miR-31-5p knockdown led to an opposite effect. These results reveal a miR-31-5p-associated regulatory network between miR-31-5p and RASA1/MAP3K1 during the progression of superiorquality brush hair traits.

The association between circulating MicroRNA-150 level and cholangiocarcinoma

Cholangiocarcinoma (CCA) is a rare tumor which requires a multimodality approach for its diagnosis. Carbohydrate antigen 19‐9 (CA19‐9) is currently the most commonly used tumor marker for CCA; nevertheless, it has certain limitations which need to be considered when using it as a tumor marker. MiRNA‐150 altered expression has been linked to the development and tumorigenesis of several cancers including CCA. This work aimed to study the serum level of CA19‐9 and miRNA‐150 expression in CCA patients and, also, to correlate their levels with tumor staging and different studied clinical and laboratory parameters. This work included 35 patients with CCA who were admitted to Hepatobiliary Unit, Alexandria Main University Hospital (Group I). Also, 35 age‐ and sex‐matched healthy subjects were included as a control group (Group II). All included subjects were submitted to measurement of serum CA19‐9 and MiRNA‐150 expression levels. Serum CA19‐9 levels showed an evident high median among CCA patients, while serum miRNA‐150 expression levels were evidently low among those patients. Moreover, combining miRNA‐150 with CA19‐9 made the accuracy of diagnosis of CCA much more reliable. Thus, miRNA‐150 can be considered as a non‐invasive, sensitive serum biomarker for the diagnosis of CCA especially when combined with CA 19‐9.

Role of RASA1 in cancer: A review and update (Review)

Ras p21 protein activator 1 (RASA1) is a regulator of Ras GDP and GTP and is involved in numerous physiological processes such as angiogenesis, cell proliferation, and apoptosis. As a result, RASA1 also contributes to pathological processes in vascular diseases and tumour formation. This review focuses on the role of RASA1 in multiple tumours types in the lung, intestines, liver, and breast. Furthermore, we discuss the potential mechanisms of RASA1 and its downstream effects through Ras/RAF/MEK/ERK or Ras/PI3K/AKT signalling. Moreover, miRNAs are capable of regulating RASA1 and could be a novel targeted treatment strategy for tumours.

MicroRNA-31 Regulates Expression of Wntless in Both Drosophila melanogaster and Human Oral Cancer Cells

Recent comparative studies have indicated distinct expression profiles of short, non-coding microRNAs (miRNAs) in various types of cancer, including oral squamous cell carcinoma (OSCC). In this study, we employed a hybrid approach using Drosophila melanogaster as well as OSCC cell lines to validate putative targets of oral cancer-related miRNAs both in vivo and in vitro. Following overexpression of Drosophila miR-31, we found a significant decrease in the size of the imaginal wing discs and downregulation of a subset of putative targets, including wntless (wls), an important regulator of the Wnt signaling pathway. Parallel experiments performed in OSCC cells have also confirmed a similar miR-31-dependent regulation of human WLS that was not initially predicted as targets of human miR-31. Furthermore, we found subsequent downregulation of cyclin D1 and c-MYC, two of the main transcriptional targets of Wnt signaling, suggesting a potential role of miR-31 in regulating the cell cycle and proliferation of OSCC cells. Taken together, our Drosophila-based in vivo system in conjunction with the human in vitro platform will thus provide a novel insight into a mammal-to-Drosophila-to-mammal approach to validate putative targets of human miRNA and to better understand the miRNA-target relationships that play an important role in the pathophysiology of oral cancer.

Role of noncoding RNAs in cholangiocarcinoma (Review)

Cholangiocarcinoma (CCA) is a malignant tumour originating from biliary epithelial cells, and is increasing in incidence. Radical surgery is the main treatment. However, the pathogenesis of CCA is unclear. Noncoding RNAs (ncRNAs) are non‑protein‑coding RNAs produced by genomic transcription that include microRNAs (miRNAs), circular RNAs (circRNAs) and long noncoding RNAs (lncRNAs). They play important roles in gene expression, epigenetic modification, cell proliferation, differentiation and reproduction. ncRNAs also serve key roles in cancer development. Numerous studies have been carried out on ncRNAs, and associated publications have shown that ncRNAs are closely associated with the physiological and pathological mechanisms of CCA. The findings of these studies can provide new insights into the diagnosis, treatment and prognosis of CCA. The present review summarizes the pathophysiological mechanisms of different types of ncRNAs, including miRNAs, circRNAs and lncRNAs in CCA, and their applications in the diagnosis and treatment of CCA.

LncRNA PCAT6 increased cholangiocarcinoma cell proliferation and invasion via modulating miR-330-5p

Long non-coding RNAs (lncRNAs) act important roles in several tumors including cholangiocarcinoma. However, the expression pattern and function of PCAT6 in intrahepatic cholangiocarcinoma remains unknown. In our research, we showed that the PCAT6 expression level was upregulated in intrahepatic cholangiocarcinoma cell lines. The expression of PCAT6 in intrahepatic cholangiocarcinoma tissues than that in noncancerous samples and the higer expression of PCAT6 was associated with advanced stage. Ectopic expression of PCAT6 induced cell proliferation and invasion in cholangiocarcinoma cell. Moreover, we demonstrated that PCAT6 interacts with miR-330-5p by directly targeting and PCAT6 overexpression inhibited the expression of miR-330-5p in the ICC-9810 cell. We also showed that the expression level of miR-330-5p in intrahepatic cholangiocarcinoma samples was downregulated compared to noncancerous tissues. Interesting, we proved that the miR-330-5p expression was negative correlated with PCAT6 expression in intrahepatic cholangiocarcinoma. Ectopic expression of miR-330-5p suppressed cell proliferation and invasion. Finally, we showed that PCAT6 induced cell proliferation and invasion by decreasing miR-330-5p in cholangiocarcinoma cell. Taken together, these data suggested that lncRNA PCAT6 was an oncogenic player in the development of intrahepatic cholangiocarcinoma.

Overexpression of the Oral Mucosa-Specific microRNA-31 Promotes Skin Wound Closure

Wounds within the oral mucosa are known to heal more rapidly than skin wounds. Recent studies suggest that differences in the microRNAome profiles may underlie the exceptional healing that occurs in oral mucosa. Here, we test whether skin wound-healing can be accelerating by increasing the levels of oral mucosa-specific microRNAs. A panel of 57 differentially expressed high expresser microRNAs were identified based on our previously published miR-seq dataset of paired skin and oral mucosal wound-healing [Sci. Rep. (2019) 9:7160]. These microRNAs were further grouped into 5 clusters based on their expression patterns, and their differential expression was confirmed by TaqMan-based quantification of LCM-captured epithelial cells from the wound edges. Of these 5 clusters, Cluster IV (consisting of 8 microRNAs, including miR-31) is most intriguing due to its tissue-specific expression pattern and temporal changes during wound-healing. The in vitro functional assays show that ectopic transfection of miR-31 consistently enhanced keratinocyte proliferation and migration. In vivo, miR-31 mimic treatment led to a statistically significant acceleration of wound closure. Our results demonstrate that wound-healing can be enhanced in skin through the overexpression of microRNAs that are highly expressed in the privileged healing response of the oral mucosa.

MicroRNA-31 reflects IL-6 expression in cancer tissue and is related with poor prognosis in bile duct cancer

Bile duct cancer is a highly aggressive malignancy wherein early diagnosis is difficult and few treatment options are available. MicroRNA-31 (miR-31) is reported to be related with survival in patients with gastrointestinal cancers; however, the regulatory mechanism of miR-31 and association between miR-31 expression and survival in patients with bile duct cancer cases have not been established. Thus, we evaluated miR-31 expression in bile duct cancer tissues and assessed its relationship with prognosis. Additionally, we examined the effects of several cytokines on miR-31 expression. The study included 81 samples of bile duct cancer tissues. MiR-31 expression in bile duct cancer cells was significantly higher than that in normal bile duct epithelial cells (P = 0.038). There were no significant associations between miR-31 expression and clinical or pathological characteristics, except for tumour size (P = 0.012). In Kaplan-Meier analysis, high miR-31 expression was significantly associated with shorter survival (log-rank test, P = 0.0082). In multivariate Cox regression analysis, high miR-31 expression was significantly associated with prognosis (P = 0.043), independent of clinical or pathological features. Interleukin-6 (IL-6) significantly promoted miR-31 expression and cell proliferation in a dose-dependent manner, and the inhibition of STAT-3 signalling significantly suppressed miR-31 expression and cell proliferation. In conclusion, high expression was significantly associated with poor prognosis in bile duct cancer patients. The IL-6-STAT-3 signalling regulated bile duct cancer cell proliferation and miR-31 expression. Our findings suggest that miR-31 may be a promising biomarker that reflects IL-6 expression in bile duct cancer tissues and predicts poor prognosis.

Prognostic role of BAP-1 and PBRM-1 expression in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) has universally poor outcome, mainly due to its late clinical presentation. Identification of specific biomarkers and development of effective treatment are still urgently required. Mutations in PBRM-1 and BAP-1 genes, and the expression of S100P have been related to survival in ICC. miR-31 seems also to play important regulatory functions in ICC and it directly regulates BAP-1 expression in lung cancer. In this study, tissue expression of BAP-1, PBRM-1, S100P, and miR-31 was investigated in ICC and correlated with clinical-pathological features. Sixty-one consecutive patients who underwent curative hepatic resection for ICC were enrolled. None received any therapy prior to surgery. Immunostaining for BAP-1, PBRM-1, and S100P, and in situ hybridization for miR-31 were performed, using tissue microarray slides. A strong retained expression of BAP-1 and PBRM-1 was associated with a reduced overall (p = 0.04 and p = 0.002, respectively) and disease-free survival (p = 0.05 and p = 0.02, respectively). An overexpression of S100P was related to a reduced overall survival (p = 0.005). The multivariate analyses identified the presence of perineural invasion and the retained PBRM-1 expression as independent predictors of worse overall [p = 0.02, hazard ratio (HR) = 2.25 (1.16-4.39) and p = 0.001, HR = 3.13 (1.56-6.28), respectively] and disease-free survivals [p = 0.03, HR = 2.43 (1.09-5.4) and p = 0.03, HR = 2.51 (1.11-5.67), respectively]. An overexpression of S100P was predictive of a worse overall survival [p = 0.02, HR = 1.66 (1.08-2.55)]. High levels of miR-31 were significantly associated to a low expression of BAP-1 protein (p = 0.03). In ICC, a retained expression of BAP-1 and PBRM-1, and an overexpression of S100P are related to a poor prognosis.

Functions and mechanisms of microRNA-31 in human cancers

MicroRNAs can exhibit opposite functions in different tumors. MiR-31 is a representative example as it can not only enhance tumor development and progression in pancreatic cancer, colorectal cancer and so on, but also inhibit tumorigenesis and induce apoptosis in ovarian cancer, prostate cancer and etc. The mechanism underlying its' pleiotropy remains unknown. Several recent studies that focused on the global gene expression changes caused by aberrant miR-31 provided information on the upstream and downstream events associated with deregulated miR-31. MiR-31 might interact with a number of signaling pathways including RAS/MARK, PI3K/AKT and RB/E2F to play its opposite functions. This review summarizes the target genes and pathways associated with miR-31 and examines the mechanisms underlying the function of miR-31. The resulting hypothesis is possible that the tissue-specific features of adenocarcinoma and squamous cell cancer and the positive feedback loop consists of miR-31 and its upstream and downstream may account for the diversity of miR-31 functions.

MicroRNA-31-5p enhances the Warburg effect via targeting FIH

The enhanced expression of miR-31 has been observed in many human malignancies including lung cancer, and this microRNA regulates several aspects of oncogenesis. However, the role of miR-31-5p in energy metabolism remains elusive. Here, we confirm that H1299 and A549 cells, 2 lung cancer cell lines, relay on aerobic glycolysis as main source of ATP. Inhibition of miR-31-5p leads to decreased glycolysis and ATP production, while miR-31-5p overexpression increases them. Hypoxia inducible factor 1 (HIF-1) up-regulates the expression of glycolytic enzymes, and the HIF-1α inhibitor (FIH) inhibits HIF-1 activity. Because FIH is a direct target of miR-31-5p, inhibition of miR-31-5p results in enhanced FIH expression and suppression of HIF-1 signaling, while overexpression of miR-31-5p has the opposite effects. Via this mechanism, miR-31-5p up-regulates aerobic glycolytic genes and maintains energy homeostasis. To further validate the mechanism of miR-31-5p in glycolysis regulation, we show that overexpression or knockdown of FIH rescued the effects of miR-31-5p or miR-31-5p inhibitor on HIF activation and its target gene expression, respectively. Finally, by means of an A549 cell xenograft mouse model, we demonstrate that the miR-31-5p promotes cell proliferation via enhancing glycolysis. In summary, this study reveals that miR-31-5p promotes the Warburg effect via direct targeting of FIH.-Zhu, B., Cao, X., Zhang, W., Pan, G., Yi, Q., Zhong, W., Yan, D. MicroRNA-31-5p enhances the Warburg effect via targeting FIH.

Triptolide inhibits vascular endothelial growth factor-mediated angiogenesis in human breast cancer cells

Triptolide has been demonstrated to induce tumor cell apoptosis. However, the role of triptolide in breast cancer angiogenesis remains unclear. The present study aimed to investigate the function of triptolide in breast cancer and the molecular mechanisms underlying this. The results revealed that triptolide could significantly decrease the expression of vascular endothelial growth factor A (VEGFA) in Hs578T and MDAMB231 breast cancer cells. Furthermore, human umbilical vein endothelial cells were used to perform tube formation and bromodeoxyuridine incorporation assays, which demonstrated an antiangiogenic effect of triptolide. In addition, the effect of triptolide in vivo was examined in a xenograft mouse model, which determined that VEGFA, cluster of differentiation 31 and anti-proliferation marker protein Ki67 expression in tumor sections was decreased in the triptolide treatment group compared with the control group. Western bolt analysis was performed to investigate the phosphorylation of extracellular signal-related kinase (ERK)1/2 and RAC-α serine/threonine-protein kinase after triptolide treatment, and it's effect on hypoxia inducible factor (HIF)1-α expression. The results demonstrated that triptolide suppressed ERK1/2 activation and HIF1-α expression. Furthermore, overexpression of HIF1-α could partially abrogate the inhibitory effect of triptolide on VEGFA expression. These results suggest that triptolide inhibits breast cancer cell angiogenesis in vitro and in vivo through inhibiting the ERK1/2-HIF1-α-VEGFA axis.

NcRNAs and Cholangiocarcinoma

Cholangiocarcinoma (CCA) is the most common primary biliary malignancy with poor prognosis. Less understanding of its etiology and pathogenesis makes the diagnosis and therapy difficult. Recently, accumulating evidences have demonstrated that deregulated expression of non-coding RNAs (ncRNAs) is closely associated with the etiopathogenesis of CCA. NcRNAs which lack open reading frame are a heterogeneous class of transcribed RNA molecules, including microRNAs, long non-coding RNAs and circular RNAs. Several studies have shown ncRNAs dysregulation is a common central event occurring in CCA and has the potential of being therapy targets. Moreover, ncRNAs can be easily detected in cancer tissues and biofluids, representing valuable tools for diagnosis. In this review, we illustrate the role of ncRNA in the CCA and discuss their potential clinical value.

MicroRNA-31 promotes adverse cardiac remodeling and dysfunction in ischemic heart disease

RATIONALE

Myocardial infarction (MI) triggers a dynamic microRNA response with the potential of yielding therapeutic targets.

OBJECTIVE

We aimed to identify novel aberrantly expressed cardiac microRNAs post-MI with potential roles in adverse remodeling in a rat model, and to provide post-ischemic therapeutic inhibition of a candidate pathological microRNA in vivo.

METHODS AND RESULTS

Following microRNA array profiling in rat hearts 2 and 14days post-MI, we identified a time-dependent up-regulation of miR-31 compared to sham-operated rats. A progressive increase of miR-31 (up to 91.4±11.3 fold) was detected in the infarcted myocardium by quantitative real-time PCR. Following target prediction analysis, reporter gene assays confirmed that miR-31 targets the 3´UTR of cardiac troponin-T (Tnnt2), E2F transcription factor 6 (E2f6), mineralocorticoid receptor (Nr3c2) and metalloproteinase inhibitor 4 (Timp4) mRNAs. In vitro, hypoxia and oxidative stress up-regulated miR-31 and suppressed target genes in cardiac cell cultures, whereas LNA-based oligonucleotide inhibition of miR-31 (miR-31i) reversed its repressive effect on target mRNAs. Therapeutic post-ischemic administration of miR-31i in rats silenced cardiac miR-31 and enhanced expression of target genes, while preserving cardiac structure and function at 2 and 4weeks post-MI. Left ventricular ejection fraction (EF) improved by 10% (from day 2 to 30 post-MI) in miR-31i-treated rats, whereas controls receiving scrambled LNA inhibitor or placebo incurred a 17% deterioration in EF. miR-31i decreased end-diastolic pressure and infarct size; attenuated interstitial fibrosis in the remote myocardium and enhanced cardiac output.

CONCLUSION

miR-31 induction after MI is deleterious to cardiac function while its therapeutic inhibition in vivo ameliorates cardiac dysfunction and prevents the development of post-ischemic adverse remodeling.

miR182 activates the Ras-MEK-ERK pathway in human oral cavity squamous cell carcinoma by suppressing RASA1 and SPRED1

Purpose

The constitutive activation of the Ras–MEK–ERK signaling pathway in oral cavity squamous cell carcinoma (OSCC) has been found to be tightly controlled at multiple levels under physiological conditions. RASA1 and SPRED1 are two important negative regulators of this pathway, but the exact regulating mechanism remains unclear. In this study, we aimed to explore the potential regulating mechanisms involved in the Ras–MEK–ERK signaling pathway in OSCC.

Materials and methods

MicroRNA (miRNA) expression was detected by quantitative reverse-transcription polymerase chain reaction. The protein levels of RASA1, SPRED1, and signaling proteins were detected by Western blot. Cell growth was determined using CCK-8 reagent, colony formation was stained by crystal violet, and cell invasion was tested using transwell chambers. Cell apoptosis and the cell cycle were then analyzed by flow cytometry. The binding of miR182 with RASA1 or SPRED1 was evaluated by luciferase reporter assays on a dual-luciferase reporter system.

Results

The expression of miR182 was found to be upregulated significantly in malignant oral carcinoma tissues compared with the adjacent nonmalignant tissues, and was inversely correlated with protein levels of RASA1 and SPRED1. Overexpression of miR182 in OSCC cell lines sustained Ras–MEK–ERK signaling-pathway activation, and promoted cell proliferation, cell-cycle progression, colony formation, and invasion capacity, whereas miR182 downregulation alleviated these properties significantly in vitro. Furthermore, we demonstrated that miR182 exerted its oncogenic role in OSCC by directly targeting and suppressing RASA1 and SPRED1.

Conclusion

Our results bring new insights into the important role of miR182 in the activation of the Ras–MEK–ERK signaling pathway, and suggest that miR182 may be used as a potential target for treatment of OSCC, prompting further investigation into miRNA antisense oligonucleotides for cancer therapy.

The Emerging Role of miRNAs and Their Clinical Implication in Biliary Tract Cancer

Biliary tract cancers are aggressive malignancies that include gallbladder cancer and tumors of intra- and extrahepatic ducts and have a poor prognosis. Surgical resection remains the main curative therapy. Nevertheless, numerous patients experience recurrence even after radical surgery. This scenario drives the research to identify biliary tract cancer biomarkers despite the limited progress that has been made. Recently, a large number of studies have demonstrated that deregulated expression of microRNAs is closely associated with cancer development and progression. In this review, we highlight the role and importance of microRNAs in biliary tract cancers with an emphasis on utilizing circulating microRNAs as potential biomarkers. Additionally, we report several single-nucleotide polymorphisms in microRNA genes that are associated with the susceptibility of biliary tract tumors.

The role of microRNAs in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary hepatic malignancy with poor prognosis. Despite improvements in its diagnosis and therapy, the prognosis for ICC patients remains poor. An improved understanding of ICC pathogenesis and consequential identification of novel therapeutic targets would improve the prognosis of ICC patients. MicroRNAs (miRNAs) are a class of highly conserved, endogenous, small non‐coding RNA molecules of 18–23 nucleotides in length, which regulate gene expression through complementary base‐pairing with target messenger RNAs and subsequent gene silencing. Several studies have shown deregulated expression of miRNAs in ICC cell lines and tissues, in which these miRNAs play important roles in ICC apoptosis, cell proliferation, invasion, migration and metastasis. In this review, we illustrate the potential role of miRNA in the pathogenesis of ICC and explore the possibilities of using miRNAs as prognostic and diagnostic markers, as well as therapeutic targets in ICC.

Function and regulation of microRNA-31 in development and disease

MicroRNAs (miRNAs) are small noncoding RNAs that orchestrate numerous cellular processes both under normal physiological conditions as well as in diseases. This review summarizes the functional roles and transcriptional regulation of the highly evolutionarily conserved miRNA, microRNA-31 (miR-31). miR-31 is an important regulator of embryonic implantation, development, bone and muscle homeostasis, and immune system function. Its own regulation is disrupted during the onset and progression of cancer and autoimmune disorders such as psoriasis and systemic lupus erythematosus. Limited studies suggest that miR-31 is transcriptionally regulated by epigenetics, such as methylation and acetylation, as well as by a number of transcription factors. Overall, miR-31 regulates diverse cellular and developmental processes by targeting genes involved in cell proliferation, apoptosis, cell differentiation, and cell motility. Mol. Reprod. Dev. 83: 654-674, 2016 © 2016 Wiley Periodicals, Inc.

The role of miRNAs in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a devastating malignancy with high mortality, in part due to the combination of late presentation, significant diagnostic challenges and limited effective treatment options. Late presentation and diagnosis contribute to the high mortality in CCA and there is an urgent unmet need for diagnostic and prognostic biomarkers to facilitate early diagnosis and treatment stratification to improve clinical outcomes. MiRs are small ncRNA molecules that regulate gene expression and modulate both tumor suppressive and oncogenic pathways. They have a well-defined role in carcinogenesis, including CCA. In this review, we outline the evidence for MiRs in the pathogenesis of CCA and their potential utility as diagnostic and prognostic biomarkers to guide clinical management.

Transcriptional Regulation of miR-31 by Oncogenic KRAS Mediates Metastatic Phenotypes by Repressing RASA1

Activating KRAS mutations are nearly ubiquitous in pancreatic cancer occurring in more than 95% of clinical cases. miRNAs are small noncoding RNAs that regulate gene expression by binding sequences within the 3'UTRs of target mRNAs. An integral role for miRNAs in cancer pathogenesis is well established; however, the role of miRNAs in KRAS-mediated tumorigenesis is poorly characterized. Here it is demonstrated that expression of miR-31 is coupled to the expression of oncogenic KRAS and activity of the MAPK pathway. miR-31 is highly expressed in patient-derived xenografts and a panel of pancreatic and colorectal cancer cells harboring activating KRAS mutations. The miR-31 host gene is a large noncoding RNA that correlates with miR-31 expression and enabled identification of the putative miR-31 promoter. Using luciferase reporters, a minimal RAS-responsive miR-31 promoter was found to drive robust luciferase activity dependent on expression of mutant KRAS and the transcription factor ELK1. Furthermore, ELK1 interacts directly with the endogenous miR-31 promoter in a MAPK-dependent manner. Expression of enforced miR-31 significantly enhanced invasion and migration of multiple pancreatic cancer cells resulting from the activation of RhoA through regulation of the miR-31 target gene RASA1. Importantly, acute knockdown of RASA1 phenocopied enforced miR-31 expression on the migratory behavior of pancreatic cancer cells through increased RhoA activation.

IMPLICATIONS

Oncogenic KRAS can activate Rho through the miR-31-mediated regulation of RASA1 indicating miR-31 acts as a KRAS effector to modulate invasion and migration in pancreatic cancer.

MicroRNAs in cholangiopathies: Potential diagnostic and therapeutic tools

Cholangiopathies are the group of diseases targeting the bile duct epithelial cells (i.e. cholangiocytes). These disorders arise from different etiologies and represent a current diagnostic, prognostic and therapeutic challenge. Different molecular mechanisms participate in the development and progression of each type of biliary disease. However, microRNA deregulation is a common central event occurring in all of them that plays a key role in their pathogenesis. MicroRNAs are highly stable small non-coding RNAs present in cells, extracellular microvesicles and biofluids, representing valuable diagnostic tools and potential targets for therapy. In the following sections, the most novel and significant discoveries in this field are summarized and their potential clinical value is highlighted.

MicroRNA-31 initiates lung tumorigenesis and promotes mutant KRAS-driven lung cancer

MicroRNA (miR) are important regulators of gene expression, and aberrant miR expression has been linked to oncogenesis; however, little is understood about their contribution to lung tumorigenesis. Here, we determined that miR-31 is overexpressed in human lung adenocarcinoma and this overexpression independently correlates with decreased patient survival. We developed a transgenic mouse model that allows for lung-specific expression of miR-31 to test the oncogenic potential of miR-31 in the lung. Using this model, we observed that miR-31 induction results in lung hyperplasia, followed by adenoma formation and later adenocarcinoma development. Moreover, induced expression of miR-31 in mice cooperated with mutant KRAS to accelerate lung tumorigenesis. We determined that miR-31 regulates lung epithelial cell growth and identified 6 negative regulators of RAS/MAPK signaling as direct targets of miR-31. Our study distinguishes miR-31 as a driver of lung tumorigenesis that promotes mutant KRAS-mediated oncogenesis and reveals that miR-31 directly targets and reduces expression of negative regulators of RAS/MAPK signaling.

MicroRNAs in the Cholangiopathies: Pathogenesis, Diagnosis, and Treatment

The cholangiopathies are a group of liver diseases resulting from different etiologies but with the cholangiocyte as the primary target. As a group, the cholangiopathies result in significant morbidity and mortality and represent one of the main indications for liver transplant in both children and adults. Contributing to this situation is the absence of a thorough understanding of their pathogenesis and a lack of adequate diagnostic and prognostic biomarkers. MicroRNAs are small non-coding RNAs that modify gene expression post-transcriptionally. They have been implicated in the pathogenesis of many diseases, including the cholangiopathies. Thus, in this review we provide an overview of the literature on miRNAs in the cholangiopathies and discuss future research directions.

MicroRNAs in liver tissue engineering - New promises for failing organs

miRNA-based technologies provide attractive tools for several liver tissue engineering approaches. Herein, we review the current state of miRNA applications in liver tissue engineering. Several miRNAs have been implicated in hepatic disease and proper hepatocyte function. However, the clinical translation of these findings into tissue engineering has just begun. miRNAs have been successfully used to induce proliferation of mature hepatocytes and improve the differentiation of hepatic precursor cells. Nonetheless, miRNA-based approaches beyond cell generation have not yet entered preclinical or clinical investigations. Moreover, miRNA-based concepts for the biliary tree have yet to be developed. Further research on miRNA based modifications, however, holds the promise of enabling significant improvements to liver tissue engineering approaches due to their ability to regulate and fine-tune all biological processes relevant to hepatic tissue engineering, such as proliferation, differentiation, growth, and cell function.

Genetic alteration regulated by microRNAs in biliary tract cancers

Biliary tract cancers (BTCs) constitute a relatively rare but highly malignant class of tumors with poor prognosis including gallbladder cancer, intra- and extra-hepatic cholangiocarcinoma. Recently, accumulated evidences have demonstrated that deregulated expression of microRNAs (miRNAs) is closely associated with the development, invasion, metastasis and prognosis of different cancers including BTCs. MiRNAs comprise an endogenously expressed and highly evolutionarily conserved group of small, non-coding, single-stranded RNAs which negatively regulate target genes expression by means of combining with 3' untranslated region (UTR) of corresponding mRNAs at the post-transcriptional level with significant roles in various fundamental cellular procedures including cell proliferation, differentiation, migration, cell cycle control and apoptosis. Recent studies have indicated that miRNAs could function as novel tumor-promoting genes or tumor suppressor genes to act as potential therapeutic targets in anticancer treatment because the genetic alteration regulated by miRNAs could result in tumorigenesis and tumor inhibition. Anomalous miRNAs expression patterns, acting as phenotypic signatures of distinct cancers, are promising to be used as diagnostic, prognostic, predictive biomarkers. In this review, we summarize the current findings from the studies about potential genetic alteration regulated by miRNAs and their roles in BTCs.

A microRNA profile associated with Opisthorchis viverrini-induced cholangiocarcinoma in tissue and plasma

BACKGROUND

Intrahepatic cholangiocarcinoma (ICC) is a highly aggressive tumor of the bile duct, and a significant public health problem in East Asia, where it is associated with infection by the parasite Opisthorchis viverrini. ICC is often detected at an advanced stage and with a poor prognosis, making a biomarker for early detection a priority.

METHODS

We have comprehensively profiled miRNA expression levels in ICC tumor tissue using small RNA-Seq and validated these profiles using quantitative PCR on matched plasma samples.

RESULTS

Distinct miRNA profiles were associated with increasing histological differentiation of ICC tumor tissue. We also observed that histologically normal tissue adjacent to ICC tumor displayed miRNA expression profiles more similar to tumor than liver tissue from healthy donors. In plasma samples, an eight-miRNA signature associated with ICC, regardless of the degree of histological differentiation of its matched tissue, forming the basis of a circulating miRNA-based biomarker for ICC.

CONCLUSIONS

The association of unique miRNA profiles with different ICC subtypes suggests the involvement of specific miRNAs during ICC tumor progression. In plasma, an eight-miRNA signature associated with ICC could form the foundation of an accessible (plasma-based) miRNA-based biomarker for the early detection of ICC.

Identification of a novel microRNA signature associated with intrahepatic cholangiocarcinoma (ICC) patient prognosis

Background

The clinical significance of microRNAs (miRNAs) in intrahepatic cholangiocarcinoma (ICC) is unclear. The objective of this study is to examine the miRNA expression profiles and identify a miRNA signature for the prognosis of ICC.

Methods

Using a custom microarray containing 1,094 probes, the miRNA expression profiles of 63 human ICCs and nine normal intrahepatic bile ducts (NIBD) were assessed. The miRNA signatures were established and their clinical significances in ICC were analyzed. The expression levels of some miRNAs were verified by quantitative real-time RT-PCR (qRT-PCR).

Results

Expression profile analysis showed 158 differentially expressed miRNAs between ICC and NIBD, with 77 up-regulated and 81 down-regulated miRNAs. From the 158 differentially expressed miRNAs, a 30-miRNA signature consisting of 10 up-regulated and 20 down-regulated miRNAs in ICC was established for distinguishing ICC from NIBD with 100% accuracy. A separate 3-miRNA signature was identified for predicting prognosis in ICC. Based on the 3-miRNA signature, a formula was constructed to compute a risk score for each patient. The patients with high-risk had significantly lower overall survival and disease-free survival than those with low-risk. The expression level of these three miRNAs detected by microarray was verified by qRT-PCR. Multivariate analysis indicated that the 3-miRNA signature was an independent prognostic predictor.

Conclusions

In this study, a 30-miRNA signature for distinguishing ICC from NIBD, and a 3-miRNA signature for evaluating prognosis of ICC were established, which might be able to serve as biomarkers for prognosis of ICC. Further studies focusing on these miRNAs may shed light on the mechanisms associated with ICC pathogenesis and progression.

MicroRNAs and benign biliary tract diseases

Cholangiocytes, the epithelial cells lining the biliary tree, represent only a small portion of the total liver cell population (3-5%), but they are responsible for the secretion of up to 40% of total daily bile volume. In addition, cholangiocytes are the target of a diverse group of liver diseases affecting the biliary tract, the cholangiopathies; for most of these conditions, the pathological mechanisms are unclear. MicroRNAs (miRNAs) are small, noncoding RNAs that posttranscriptionally regulate gene expression. Thus, it is not surprising that altered miRNA profiles underlie the dysregulation of several proteins involved in the pathobiology of the cholangiopathies, as well as showing promise as diagnostic and prognostic tools. Here the authors review recent work relevant to the role of miRNAs in the etiopathogenesis of several of the cholangiopathies (i.e., fibroinflammatory cholangiopathies and polycystic liver diseases), discuss their value as prognostic and diagnostic tools, and provide suggestions for further research.

Upregulated circulating miR-150 is associated with the risk of intrahepatic cholangiocarcinoma

During the last decade, microRNAs (miRNAs) have been identified as potential biomarkers and therapeutic targets for multiple malignancies; yet, few studies exist on intrahepatic cholangiocarcinoma (ICC). In the present study, a miRNA microarray was applied to determine the significant miRNAs involved in ICC. miR-150 was found to be significantly downregulated in ICC. We further enrolled 15 ICC patients who received radical resection to test these findings in plasma. Using quantitative reverse transcription-polymerase chain reaction (qRT-PCR), we examined and quantified the expression levels of miR-150 in tumor tissues, peritumoral noncancerous tissues and blood samples of 15 ICC patients. The diagnostic value of plasma miR-150 for differentiating patients with ICC from the age- and gender-matched controls was analyzed. For plasma samples, compared with normal controls, the level of miR-150 expression was found to be upregulated (P<0.010) in ICC patients. While differentiating ICC from normal controls, receiver operator curve (ROC) analysis of plasma miR-150 revealed the area under the curve (AUC) of 0.764 (P<0.010) with sensitivity of 80.6% and specificity of 58.1%. The diagnostic value of carbohydrate antigen 19-9 (CA19-9) and the combination of miR-150 and CA19-9 were also evaluated. We found that the combination of these two markers improved the power of screening ICC. Moreover, on the basis of the plasma miR-150 level, 15 ICC patients were divided into a low or high expression group. We found that plasma miR-150 is a potential diagnostic biomarker for ICC.

MicroRNAs in Cholangiopathies

Cholangiocytes, the cells lining bile ducts, comprise a small fraction of the total cellular component of the liver, yet perform the essential role of bile modification and transport of biliary and blood constituents. Cholangiopathies are a diverse group of biliary disorders with the cholangiocyte as the target cell; the etiopathogenesis of most cholangiopathies remains obscure. MicroRNAs are small non-coding RNAs that post-transcriptionally regulate gene expression. These small RNAs may not only be involved in the etiopathogenesis of disease, but are showing promise as diagnostic and prognostic tools. In this brief review, we summarize recent work regarding the role of microRNAs in the etiopathogenesis of several cholangiopathies, and discuss their utility as prognostic and diagnostic tools.

Prognostic role of microRNA-31 in various cancers: a meta-analysis

To date, many studies have shown that microRNAs (miRNA) exhibit altered expression levels in various cancers and may play a potential role as diagnostic and prognostic biomarkers of cancers. This meta-analysis was designed to evaluate the exact role of microRNA-31 (miR-31) for survival and discuss the possibility of utilizing miR-31 to predict the prognosis of patients with various human cancers. Electronic literature databases including PubMed, Web of Science, and Embase were searched for articles published until May 2014. The articles only written in English were considered. Data were extracted from studies comparing overall survival (OS), cancer-specific survival (CSS), or postoperative survival (PS) in patients with multiple cancers, which showed higher miR-31 expression than with similar patients. Pooled hazard ratios (HRs) of miR-31 for survival and 95 % confidence intervals (CI) were calculated. Ten studies with a total of 1,648 participants were included for the meta-analysis. For OS, the pooled HRs of higher miR-31 expression in cancers indicated significant predictor poorer survival in general cancers in either univariate analysis (HR=2.34, 95 % CI=1.15-3.52, P<0.05) or multivariate analysis (HR=1.15, 95 % CI=1.04-1.26, P<0.05). For CSS, elevated miR-31 was also a significant predictor to general cancers in multivariate analysis (HR=1.77, 95 % CI=1.06-2.47, P<0.05). And, no association was found between miR-31 expression and PS. In conclusion, the present findings indicate that high miR-31 expression is associated with poor OS and CSS in patients with general cancers and miR-31 may be a useful clinical prognostic biomarker.

Emerging insights into the role of microRNAs in the pathogenesis of cholangiocarcinoma

The microRNAs (miRNAs) are small noncoding RNAs that are potent regulators of gene expression and can regulate several diverse biological functions. This minireview provides an overview of recent studies that have examined the role and involvement of miRNAs in cholangiocarcinomas. These studies provide evidence for deregulated expression of miRNA and are providing new insights into the potential contribution of these in the pathogenesis of cholangiocarcinoma.