The miR-24-Bim pathway promotes tumor growth and angiogenesis in pancreatic carcinoma

Using microRNAs Networks to Understand Pancreatic Cancer-A Literature Review

Pancreatic cancer is a severe disease, challenging to diagnose and treat, and thereby characterized by a poor prognosis and a high mortality rate. Pancreatic ductal adenocarcinoma (PDAC) represents approximately 90% of pancreatic cancer cases, while other cases include neuroendocrine carcinoma. Despite the growing knowledge of the pathophysiology of this cancer, the mortality rate caused by it has not been effectively reduced. Recently, microRNAs have aroused great interest among scientists and clinicians, as they are negative regulators of gene expression, which participate in many processes, including those related to the development of pancreatic cancer. The aim of this review is to show how microRNAs (miRNAs) affect key signaling pathways and related cellular processes in pancreatic cancer development, progression, diagnosis and treatment. We included the results of in vitro studies, animal model of pancreatic cancer and those performed on blood, saliva and tumor tissue isolated from patients suffering from PDAC. Our investigation identified numerous dysregulated miRNAs involved in KRAS, JAK/STAT, PI3/AKT, Wnt/β-catenin and TGF-β signaling pathways participating in cell cycle control, proliferation, differentiation, apoptosis and metastasis. Moreover, some miRNAs (miRNA-23a, miRNA-24, miRNA-29c, miRNA-216a) seem to be engaged in a crosstalk between signaling pathways. Evidence concerning the utility of microRNAs in the diagnosis and therapy of this cancer is poor. Therefore, despite growing knowledge of the involvement of miRNAs in several processes associated with pancreatic cancer, we are beginning to recognize and understand their role and usefulness in clinical practice.

The role of microRNA-9 in ovarian and cervical cancers: An updated overview

Ovarian and cervical cancers are the two most frequent kind of gynaecological cancers (GCs). In spite of advances in prevention, screening and treatment, cervical cancer still leads to an increased morbidity and mortality worldwide. Ovarian cancer is often detected at a late stage, which significantly reduces the effectiveness of available treatments. Therefore, novel methods are desperately needed to improve the clinical care of GC patients. MicroRNAs, also known as short noncoding RNAs (miRNAs/miRs), are a diverse group of RNAs with a length of 22 nucleotides. These typically cause translational repression and mRNA degradation by interacting with target mRNAs' 3' untranslated region (3'-UTR), together with other regions and gene promoters. Under certain conditions, they are also able to activate translation or regulate transcription. It has been demonstrated that miRNAs are crucial to several biological processes leading to tumorigenesis, including GCs. Recent research has shown that miR-9 affects carcinogenesis. In this review, we will provide an overview of current research on the potential utility of miR-9 in the diagnosis, prognosis, and therapy of ovarian and cervical malignancies.

Development of a Serum-Based MicroRNA Signature for Early Detection of Pancreatic Cancer: A Multicenter Cohort Study

BACKGROUND

A grim prognosis of pancreatic cancer (PCa) was attributed to the difficulty in early diagnosis of the disease.

AIMS

Identifying novel biomarkers for early detection of PCa is thus urgent to improve the overall survival rates of patients.

METHODS

The study was performed firstly by identification of candidate microRNAs (miRNAs) in formalin-fixed, paraffin-embedded tissues using microarray profiles, and followed by validation in a serum-based cohort study to assess clinical utility of the candidates. In the cohorts, a total of 1273 participants from four centers were retrospectively recruited as two cohorts including training and validation cohort. The collected serum specimens were analyzed by real-time polymerase chain reaction.

RESULTS

We identified 27 miRNAs expressed differentially in PCa tissues as compared to the benign. Of which, the top-four was selected as a panel whose diagnostic efficacy was fully assessed in the serum specimens. The panel exhibited superior to CA19-9, CA125, CEA and CA242 in discriminating patients with early stage PCa from healthy controls or non-PCa including chronic pancreatitis as well as pancreatic cystic neoplasms, with the area under the curves (AUC) of 0.971 (95% CI 0.956-0.987) and 0.924 (95% CI 0.899-0.949), respectively. Moreover, the panel eliminated interference from other digestive tumors with a specificity of 90.2%.

CONCLUSIONS

A panel of four serum miRNAs was developed showing remarkably discriminative ability of early stage PCa from either healthy controls or other pancreatic diseases, suggesting it may be developed as a novel, noninvasive approach for early screening of PCa in clinic.

Knockdown of miR-24 Suppressed the Tumor Growth of Cervical Carcinoma Through Regulating PTEN/PI3K/AKT Signaling Pathway

Cervical cancer (CC) is the most prevalent malignant tumor in gynecology. Despite routine surgery, advanced CC is hard to remove completely. MicroRNA-24 (miR-24) regulates several types of tumors, but its regulatory function in CC was previously unknown. We established stable knockdown of miR-24 and phosphatase and tensin homolog (PTEN) in CC cells. We measured mRNA and protein expression with RT-PCR and western blotting. We evaluated cell proliferation, invasion, migration, and apoptosis with CCK8, Transwell, wound healing, and flow cytometry, respectively. We also examined the influence of miR-24 and PTEN on tumor growth in a metastatic tumor model in nude mice. The expression of miR-24 was significantly increased in CC tissues and cell lines (C-33A, HeLa S3, SiHa). MiR-24 inhibitor greatly suppressed PTEN/PI3K/AKT, while miR-24 mimic markedly activated this signaling pathway. Knockdown of PTEN significantly reversed the effects of miR-24 inhibitor on cell proliferation, invasion, migration, and apoptosis of CC cells. The significant inhibition effect of tumor growth and ki67 expression caused by miR-24 inhibitor was reversed by si-PTEN. MiR-24 inhibitor significantly suppressed cell proliferation, invasion, migration, epithelial-mesenchymal transition (EMT) process, and tumor growth, while promoting cell apoptosis. However, the influence of miR-24 inhibitor was markedly reversed by si-PTEN. Targeting miR-24 could provide a novel therapeutic strategy for the prevention and treatment of CC.

Investigating the regulatory role of miRNAs as silent conductors in the management of pathogenesis and therapeutic resistance of pancreatic cancer

Pancreatic cancer (PC) has the greatest mortality rate of all the main malignancies. Its advanced stage and poor prognosis place it at the bottom of all cancer sites. Hence, emerging biomarkers can enable precision medicine where PC therapy is tailored to each patient. This highlights the need for new, highly sensitive and specific biomarkers for early PC diagnosis. Prognostic indicators are also required to stratify PC patients. To avoid ineffective treatment, adverse events, and expenses, biomarkers are also required for patient monitoring and identifying responders to treatment. There is substantial evidence that microRNAs (miRs, miRNAs) play a critical role in regulating mRNA and, as a consequence, protein expression in normal and malignant tissues. Deregulated miRNA profiling in PC can help with diagnosis, treatment planning, and prognosis. Furthermore, knowledge of the primary effector genes and downstream pathways in PC can help pinpoint potential miRNAs for use in treatment. Different miRNA expression profiles may serve as diagnostic, prognostic markers, and therapeutic targets across the spectrum of malignant pancreatic illness. Dysregulation of miRNAs has been linked to the malignant pathophysiology of PC through affecting many cellular functions such as increasing invasive and proliferative prospect, supporting angiogenesis, cell cycle aberrance, apoptosis elusion, metastasis promotion, and low sensitivity to particular treatments. Accordingly, in the current review, we summarize the recent advances in the roles of oncogenic and tumor suppressor (TS) miRNAs in PC and discuss their potential as worthy diagnostic and prognostic biomarkers for PC, as well as their significance in PC pathogenesis and anticancer drug resistance.

Microbiome and MicroRNA or Long Non-Coding RNA-Two Modern Approaches to Understanding Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of humans' most common and fatal neoplasms. Nowadays, a number of PDAC studies are being conducted in two different fields: non-coding RNA (especially microRNA and long non-coding RNA) and microbiota. It has been recently discovered that not only does miRNA affect particular bacteria in the gut microbiome that can promote carcinogenesis in the pancreas, but the microbiome also has a visible impact on the miRNA. This suggests that it is possible to use the combined impact of the microbiome and noncoding RNA to suppress the development of PDAC. Nevertheless, insufficient research has focused on bounding both approaches to the diagnosis, treatment, and prevention of pancreatic ductal adenocarcinoma. In this article, we summarize the recent literature on the molecular basis of carcinogenesis in the pancreas, the two-sided impact of particular types of non-coding RNA and the pancreatic cancer microbiome, and possible medical implications of the discovered phenomenon.

Recent Advances in Extracellular Vesicles in Amyotrophic Lateral Sclerosis and Emergent Perspectives

Amyotrophic lateral sclerosis (ALS) is a severe and incurable neurodegenerative disease characterized by the progressive death of motor neurons, leading to paralysis and death. It is a rare disease characterized by high patient-to-patient heterogeneity, which makes its study arduous and complex. Extracellular vesicles (EVs) have emerged as important players in the development of ALS. Thus, ALS phenotype-expressing cells can spread their abnormal bioactive cargo through the secretion of EVs, even in distant tissues. Importantly, owing to their nature and composition, EVs' formation and cargo can be exploited for better comprehension of this elusive disease and identification of novel biomarkers, as well as for potential therapeutic applications, such as those based on stem cell-derived exosomes. This review highlights recent advances in the identification of the role of EVs in ALS etiopathology and how EVs can be promising new therapeutic strategies.

miR-24-3p down-regulates the expression of the apoptotic factors FasL and BIM in human natural killer cells

MicroRNAs are involved in the regulation of different functions in immune and non-immune cells. Here we show that miR-24-3p functionally interacts with FASLG mRNA and down-regulates its expression. This interaction occurs in human natural killer cells (NK), leading to the modulation of FasL surface expression. Moreover, miR-24-3p also modulates the mRNA and protein expression of BIM in NK cells. Thus, it likely contributes to the control of both the extrinsic and intrinsic apoptotic pathways. In line with this hypothesis, inhibition of miR-24-3p improves both initiator caspase-8 and effector caspase-3 and -7 activities, increases cell apoptosis, and reduces cell viability. Our data suggest that miR-24-3p can act as a survival factor in NK cells, affecting the FasL-mediated killing of Fas expressing cells and the BIM-dependent cell death. More generally, miR-24-3p may condition the level of cell apoptosis, which increases at the contraction phase of the immune response when the clearance of various expanded effector cells is needed.

mRNA-miRNA bipartite networks reconstruction in different tissues of bladder cancer based on gene co-expression network analysis

Bladder cancer (BC) is one of the most important cancers worldwide, and if it is diagnosed early, its progression in humans can be prevented and long-term survival will be achieved accordingly. This study aimed to identify novel micro-RNA (miRNA) and gene-based biomarkers for diagnosing BC. The microarray dataset of BC tissues (GSE13507) listed in the GEO database was analyzed for this purpose. The gene expression data from three BC tissues including 165 primary bladder cancer (PBC), 58 normal looking-bladder mucosae surrounding cancer (NBMSC), and 23 recurrent non-muscle invasive tumor tissues (RNIT) were used to reconstruct gene co-expression networks. After preprocessing and normalization, deferentially expressed genes (DEGs) were obtained and used to construct the weighted gene co-expression network (WGCNA). Gene co-expression modules and low-preserved modules were extracted among BC tissues using network clustering. Next, the experimentally validated mRNA-miRNA interaction information were used to reconstruct three mRNA-miRNA bipartite networks. Reactome pathway database and Gene ontology (GO) was subsequently performed for the extracted genes of three bipartite networks and miRNAs, respectively. To further analyze the data, ten hub miRNAs (miRNAs with the highest degree) were selected in each bipartite network to reconstruct three bipartite subnetworks. Finally, the obtained biomarkers were comprehensively investigated and discussed in authentic studies. The obtained results from our study indicated a group of genes including PPARD, CST4, CSNK1E, PTPN14, ETV6, and ADRM1 as well as novel miRNAs (e.g., miR-16-5p, miR-335-5p, miR-124-3p, and let-7b-5p) which might be potentially associated with BC and could be a potential biomarker. Afterward, three drug-gene interaction networks were reconstructed to explore candidate drugs for the treatment of BC. The hub miRNAs in the mRNA-miRNA bipartite network played a fundamental role in BC progression; however, these findings need further investigation.

Versatile role of miR-24/24-1*/24-2* expression in cancer and other human diseases

MiRNAs (miRs) have been proven to be well-validated therapeutic targets. Emerging evidence has demonstrated that intricate, intrinsic and paradoxical functions of miRs are context-dependent because of their multiple upstream regulators, broad spectrum of downstream molecular targets and distinct expression in various tissues, organs and disease states. Targeted therapy has become an emerging field of research. One key for the development of successful miR-based/targeted therapy is to acquire integrated knowledge of its regulatory network and its association with disease phenotypes to identify critical nodes of the underlying pathogenesis. Herein, we systematically summarized the comprehensive role of miR-24-3p (miR-24), along with its passenger strands miR-24-1-5p* (miR-24-1) and miR-24-2-5p* (miR-24-2), emphasizing their microenvironment, intracellular targets, and associated gene networks and regulatory phenotypes in 18 different cancer types and 13 types of other disorders. MiR-24 targets and regulates numerous genes in various cancer types and enhances the expression of several oncogenes (e.g., cMyc, BCL2 and HIF1), which are challenging in terms of druggability. In contrast, several tumor suppressor proteins (p21 and p53) have been reported to be downregulated by miR-24. MiR-24 also regulates the cell cycle and is associated with numerous cancer hallmarks such as apoptosis, proliferation, metastasis, invasion, angiogenesis, autophagy, drug resistance and other diseases pathogenesis. Overall, miR-24 plays an emerging role in the diagnosis, prognosis and pathobiology of various diseases. MiR-24 is a potential target for targeted therapy in the era of precision medicine, which expands the landscape of targetable macromolecules, including undruggable proteins.

Metastatic pancreatic cancer: Mechanisms and detection (Review)

Pancreatic cancer (PC) is a lethal malignancy. Its prevalence rate remains low but continues to grow each year. Among all stages of PC, metastatic PC is defined as late-stage (stage IV) PC and has an even higher fatality rate. Patients with PC do not have any specific clinical manifestations. Most cases are inoperable at the time-point of diagnosis. Prognosis is also poor even with curative-intent surgery. Complications during surgery, postoperative pancreatic fistula and recurrence with metastatic foci make the management of metastatic PC difficult. While extensive efforts were made to improve survival outcomes, further elucidation of the molecular mechanisms of metastasis poses a formidable challenge. The present review provided an overview of the mechanisms of metastatic PC, summarizing currently known signaling pathways (e.g. epithelial-mesenchymal transition, NF-κB and KRAS), imaging that may be utilized for early detection and biomarkers (e.g. carbohydrate antigen 19-9, prostate cancer-associated transcript-1, F-box/LRR-repeat protein 7 and tumor stroma), giving insight into promising therapeutic targets.

Angiogenesis-related non-coding RNAs and gastrointestinal cancer

Gastrointestinal (GI) cancers are among the main reasons for cancer death globally. The deadliest types of GI cancer include colon, stomach, and liver cancers. Multiple lines of evidence have shown that angiogenesis has a key role in the growth and metastasis of all GI tumors. Abnormal angiogenesis also has a critical role in many non-malignant diseases. Therefore, angiogenesis is considered to be an important target for improved cancer treatment. Despite much research, the mechanisms governing angiogenesis are not completely understood. Recently, it has been shown that angiogenesis-related non-coding RNAs (ncRNAs) could affect the development of angiogenesis in cancer cells and tumors. The broad family of ncRNAs, which include long non-coding RNAs, microRNAs, and circular RNAs, are related to the development, promotion, and metastasis of GI cancers, especially in angiogenesis. This review discusses the role of ncRNAs in mediating angiogenesis in various types of GI cancers and looks forward to the introduction of mimetics and antagonists as possible therapeutic agents.

Thrombin-induced miRNA-24-1-5p upregulation promotes angiogenesis by targeting prolyl hydroxylase domain 1 in intracerebral hemorrhagic rats

OBJECTIVE

Thrombin is a unique factor that triggers post-intracerebral hemorrhage (ICH) angiogenesis by increasing hypoxia-inducible factor-1α (HIF-1α) at the protein level. However, HIF-1α mRNA remains unchanged. MicroRNAs (miRNAs) mediate posttranscriptional regulation by suppressing protein translation from mRNAs. This study aimed to determine if miRNAs might be involved in thrombin-induced angiogenesis after ICH by targeting HIF-1α or its upstream prolyl hydroxylase domains (PHDs).

METHODS

The study was divided into two parts. In part 1, rats received an injection of thrombin into the right globus pallidus. An miRNA array combined with miRNA target prediction, luciferase activity assay, and miRNA mimic/inhibitor transfection were used to identify candidate miRNAs and target genes. Part 2 included experiments 1 and 2. In experiment 1, rats were randomly divided into the sham group, ICH group, and ICH+hirudin-treated (thrombin inhibitor) group. In experiment 2, the rats were randomly divided into the sham group, ICH group, ICH+antagomir group, ICH+antagomir-control group, and ICH+vehicle group. Western blotting and quantitative real-time polymerase chain reaction were used to determine the expression of protein and miRNA, respectively. The coexpression of miR-24-1-5p (abbreviated to miR-24) and von Willebrand factor was detected by in situ hybridization and immunohistochemical analysis. The angiogenesis was evaluated by double-labeling immunofluorescence. Neurological function was evaluated by body weight, modified Neurological Severity Scores, and corner turn and foot-fault tests.

RESULTS

In part 1, it was shown that miR-24, which is predicted to target PHD1, was upregulated (fold-change of 1.83) after thrombin infusion, and that the miR-24 mimic transfection decreased luciferase activity and downregulated PHD1 expression (p < 0.05). miR-24 inhibitor transfection increased PHD1 expression (p < 0.05). In part 2, it was shown that miR-24 was expressed in endothelial cells. The HIF-1α protein level and proliferating cell nuclear antigen-positive (PCNA+) nuclei in vessels were increased, while the PHD1 protein level was decreased after ICH, and these effects were reversed by hirudin (p < 0.05). The antagomiR-24-treated rats exhibited a markedly lower body weight and significantly poorer recovery from neurological deficit compared with those in ICH groups (p < 0.05). AntagomiR-24 intervention also led to lower miR-24 expression, a higher PHD1 protein level, and fewer PCNA+ nuclei in vessels compared with those in ICH groups (p < 0.05).

CONCLUSIONS

The present study suggests that thrombin reduces HIF-1α degradation and initiates angiogenesis by increasing miR-24, which targets PHD1 after ICH.

MicroRNA-Regulated Signaling Pathways: Potential Biomarkers for Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the most aggressive and invasive type of pancreatic cancer (PCa) and is expected to be the second most common cause of cancer-associated deaths. The high mortality rate is due to the asymptomatic progression of the clinical features until the advanced stages of the disease and the limited effectiveness of the current therapeutics. Aberrant expression of several microRNAs (miRs/miRNAs) has been related to PDAC progression and thus they could be potential early diagnostic, prognostic, and/or therapeutic predictors for PDAC. miRs are small (18 to 24 nucleotides long) non-coding RNAs, which regulate the expression of key genes by targeting their 3′-untranslated mRNA region. Increased evidence has also suggested that the chemoresistance of PDAC cells is associated with metabolic alterations. Metabolic stress and the dysfunctionality of systems to compensate for the altered metabolic status of PDAC cells is the foundation for cellular damage. Current data have implicated multiple systems as hallmarks of PDAC development, such as glutamine redox imbalance, oxidative stress, and mitochondrial dysfunction. Hence, both the aberrant expression of miRs and dysregulation in metabolism can have unfavorable effects in several biological processes, such as apoptosis, cell proliferation, growth, survival, stress response, angiogenesis, chemoresistance, invasion, and migration. Therefore, due to these dismal statistics, it is crucial to develop beneficial therapeutic strategies based on an improved understanding of the biology of both miRs and metabolic mediators. This review focuses on miR-mediated pathways and therapeutic resistance mechanisms in PDAC and evaluates the impact of metabolic alterations in the progression of PDAC.

Prognostic significance of microRNA miR-24 in cancers: a meta-analysis

The prognostic significance of miR-24 in tumors has not been determined. Therefore, we conducted a meta-analysis to systematically assess the correlation between miR-24 and its prognostic value in cancers PubMed, EMBASE, and Web of Science databases were used to search relevant articles (up to 1 October 2020). Studies that evaluated the prognostic value of miR-24 in tumors were included. The hazard ratio (HR) and odds ratio (OR) with 95% confidence intervals (CI) were used to evaluate survival outcomes and clinical characteristics. All data analyses were implemented using STATA 12.0 software. A total of 17 studies from 15 articles involving 1705 patients were collected for the meta-analysis. The pooled analysis revealed that elevated miR-24 expression was obviously associated with poor overall survival (OS) (HR = 1.66, 95% CI: 1.20-2.31). Furthermore, we also found that elevated miR-24 expression was positively correlated with tumor size (large or small) and tumor stage (III-IV vs I-II). Elevated miR-24 expression indicates poor prognosis and may be a promising prognostic marker in different cancers. Our findings needed to be verified through further investigations. [Figure: see text].

miR24-3p activity after delivery into pancreatic carcinoma cell lines exerts profound tumor-inhibitory effects through distinct pathways of apoptosis and autophagy induction

Pancreatic cancer is among the most detrimental tumors, with novel treatment options urgently needed. The pathological downregulation of a miRNA in tumors can lead to the overexpression of oncogenes, thus suggesting miRNA replacement as novel strategy in cancer therapy. While the role of miR24 in cancer, including pancreatic carcinoma, has been described as ambiguous, it may hold great promise and deserves further studies. Here, we comprehensively analyze the effects of miR24-3p replacement in a set of pancreatic carcinoma cell lines. Transfection of miR24-3p mimics leads to profound cell inhibition in various 2D and 3D cell assays, based on the induction of apoptosis, autophagy and ROS. Comprehensive analyses of miR24-3p effects on the molecular level reveal the transcriptional regulation of several important oncogenes and oncogenic pathways. Based on these findings, miRNA replacement therapy was preclinically explored by treating tumor xenograft-bearing mice with miR24-3p mimics formulated in polymeric nanoparticles. The obtained tumor inhibition was associated with the induction of apoptosis and necrosis. Taken together, we identify miR24-3p as powerful tumor-inhibitory miRNA for replacement therapy, and describe a complex network of oncogenic pathways affected by miR24.

microRNAs Biogenesis, Functions and Role in Tumor Angiogenesis

microRNAs (miRNAs) are small non-coding RNA molecules, evolutionary conserved. They target more than one mRNAs, thus influencing multiple molecular pathways, but also mRNAs may bind to a variety of miRNAs, either simultaneously or in a context-dependent manner. miRNAs biogenesis, including miRNA transcription, processing by Drosha and Dicer, transportation, RISC biding, and miRNA decay, are finely controlled in space and time. miRNAs are critical regulators in various biological processes, such as differentiation, proliferation, apoptosis, and development in both health and disease. Their dysregulation is involved in tumor initiation and progression. In tumors, they can act as onco-miRNAs or oncosuppressor-miRNA participating in distinct cellular pathways, and the same miRNA can perform both activities depending on the context. In tumor progression, the angiogenic switch is fundamental. miRNAs derived from tumor cells, endothelial cells, and cells of the surrounding microenvironment regulate tumor angiogenesis, acting as pro-angiomiR or anti-angiomiR. In this review, we described miRNA biogenesis and function, and we update the non-classical aspects of them. The most recent role in the nucleus, as transcriptional gene regulators and the different mechanisms by which they could be dysregulated, in tumor initiation and progression, are treated. In particular, we describe the role of miRNAs in sprouting angiogenesis, vessel co-option, and vasculogenic mimicry. The role of miRNAs in lymphoma angiogenesis is also discussed despite the scarcity of data. The information presented in this review reveals the need to do much more to discover the complete miRNA network regulating angiogenesis, not only using high-throughput computational analysis approaches but also morphological ones.

Non-coding RNAs regulate angiogenic processes

Angiogenesis has critical roles in numerous physiologic processes during embryonic and adult life such as wound healing and tissue regeneration. However, aberrant angiogenic processes have also been involved in the pathogenesis of several disorders such as cancer and diabetes mellitus. Vascular endothelial growth factor (VEGF) is implicated in the regulation of this process in several physiologic and pathologic conditions. Notably, several non-coding RNAs (ncRNAs) have been shown to influence angiogenesis through modulation of expression of VEGF or other angiogenic factors. In the current review, we summarize the function and characteristics of microRNAs and long non-coding RNAs which regulate angiogenic processes. Understanding the role of these transcripts in the angiogenesis can facilitate design of therapeutic strategies to defeat the pathogenic events during this process especially in the human malignancies. Besides, angiogenesis-related mechanisms can improve tissue regeneration after conditions such as arteriosclerosis, myocardial infarction and limb ischemia. Thus, ncRNA-regulated angiogenesis can be involved in the pathogenesis of several disorders.

MicroRNA in Pancreatic Cancer: From Biology to Therapeutic Potential

Pancreatic cancer is one of the most aggressive malignancies, accounting for more than 45,750 deaths annually in the U.S. alone. The aggressive nature and late diagnosis of pancreatic cancer, coupled with the limitations of existing chemotherapy, present the pressing need for the development of novel therapeutic strategies. Recent reports have demonstrated a critical role of microRNAs (miRNAs) in the initiation, progression, and metastasis of cancer. Furthermore, aberrant expressions of miRNAs have often been associated with the cause and consequence of pancreatic cancer, emphasizing the possible use of miRNAs in the effective management of pancreatic cancer patients. In this review, we provide a brief overview of miRNA biogenesis and its role in fundamental cellular process and miRNA studies in pancreatic cancer patients and animal models. Subsequent sections narrate the role of miRNA in, (i) cell cycle and proliferation; (ii) apoptosis; (iii) invasions and metastasis; and (iv) various cellular signaling pathways. We also describe the role of miRNA's in pancreatic cancer; (i) diagnosis; (ii) prognosis and (iii) therapeutic intervention. Conclusion section describes the gist of review with future directions.

Overexpression miR-24-3p repressed Bim expression to confer tamoxifen resistance in breast cancer

Endocrine therapy resistance represents a major challenge to the successful treatment of patients with breast cancer. The development of tamoxifen resistance commonly occurrs during the treatment of patients with breast cancer whereas its underlying mechanisms remain elusive. Here, we found that miR-24-3p regulated tamoxifen sensitivity in breast cancer cells. Forced overexpression of miR-24-3p augmented tamoxifen-induced cell viability inhibition in breast cancer cells, while knockdown of miR-24-3p partially attenuated the cytotoxicity effect of tamoxifen. Moreover, we discovered Bim as a target gene of miR-24-3p in breast cancer cells by RNA immunoprecipitation, quantitative reverse transcription polymerase chain reaction, Western blot, and dual luciferase reporter assay. In our established tamoxifen resistant MCF7 cell line (MCF7/TAM), there was a significant elevation of miR-24-3p and decrease of BIM expression compared with parental MCF7 cells. In addition, the inhibition of miR-24-3p could reverse the tamoxifen resistance of MCF7/TAM cells by the induction of cell apoptosis. Silencing of Bim expression blocked miR-24-3p inhibitor-induced elevation of tamoxifen sensitivity of MCF7/TAM cells. Using tumor tissues from patients with breast cancer, we also found that the expression of miR-24-3p was negatively correlated with Bim mRNA expression. Collectively, our study highlighted the pivotal role of miR-24-3p overexpression in mediating the development of tamoxifen resistance in breast cancer and suggested miR-24-3p might be a predictor or target for patients with breast cancer.

Plasma Micro-RNA Alterations Appear Late in Pancreatic Cancer

Objectives:

The aim of this research was to study whether plasma microRNAs (miRNA) can be used for early detection of pancreatic cancer (PC) by analyzing prediagnostic plasma samples collected before a PC diagnosis.

Background:

PC has a poor prognosis due to late presenting symptoms and early metastasis. Circulating miRNAs are altered in PC at diagnosis but have not been evaluated in a prediagnostic setting.

Methods:

We first performed an initial screen using a panel of 372 miRNAs in a retrospective case-control cohort that included early-stage PC patients and healthy controls. Significantly altered miRNAs at diagnosis were then measured in an early detection case-control cohort wherein plasma samples in the cases are collected before a PC diagnosis. Carbohydrate antigen 19–9 (Ca 19–9) levels were measured in all samples for comparison.

Results:

Our initial screen, including 23 stage I-II PC cases and 22 controls, revealed 15 candidate miRNAs that were differentially expressed in plasma samples at PC diagnosis. We combined all 15 miRNAs into a multivariate statistical model, which outperformed Ca 19–9 in receiver-operating characteristics analysis. However, none of the candidate miRNAs, individually or in combination, were significantly altered in prediagnostic plasma samples from 67 future PC patients compared with 132 matched controls. In comparison, Ca 19–9 levels were significantly higher in the cases at <5 years before diagnosis.

Conclusion:

Plasma miRNAs are altered in PC patients at diagnosis, but the candidate miRNAs found in this study appear late in the course of the disease and cannot be used for early detection of the disease.

Association between small intestinal bacterial overgrowth and toll-like receptor 4 in patients with pancreatic carcinoma and cholangiocarcinoma

BACKGROUND/AIMS

Multiple factors have been linked to pathogenesis of pancreatic cancer and cholangiocarcinoma. Until now, few studies have investigated the role of small intestinal bacterial overgrowth (SIBO) and toll-like receptor 4 (TLR-4) signaling in these diseases. This study aimed to examine the relationship between the prevalence of SIBO and the TLR-4 expression in patients with pancreatic carcinoma and cholangiocarcinoma.

MATERIALS AND METHODS

A total of 90 human subjects suffering from pancreatic carcinoma (n=30), cholangiocarcinoma (n=30), and healthy controls (n=30) were enrolled in the study. A glucose hydrogen breath test (GHBT) was used to evaluate SIBO. The TLR4 protein expression was measured by immunohistochemistry (IHC).

RESULTS

The positive rate of SIBO was 63.3% in the pancreatic cancer group and 46.7% in patients with cholangiocarcinoma, which was significantly greater than 13.3% in the healthy control group (p<0.05). An IHC analysis revealed that the TLR-4 protein expression in the SIBO-positive pancreatic carcinoma patients was significantly higher than that in the SIBO-negative patients (p<0.05), and the same result was in the cholangiocarcinoma subjects. In addition, a correlation analysis identified the positive relationship between the prevalence of SIBO and the TLR-4 protein expression in pancreatic carcinoma (r=0.489), and the same result was in the cholangiocarcinoma subjects.

CONCLUSION

Our findings indicate a high prevalence of SIBO in pancreatic carcinoma and cholangiocarcinoma, and SIBO displays a positive correlation with the TLR-4 expression, suggesting that SIBO could be a risk factor for the pathogenesis of pancreatic carcinoma and cholangiocarcinoma, in which the TLR4 signaling may be involved.

Identification of microRNAs related to myocardial ischemic reperfusion injury

Previous studies have suggested that microRNAs (miRNAs) are associated with the progression of myocardial ischemic reperfusion (I/R) injury. However, inconsistent results have been obtained due to the differences in sequencing platform, control selection, and filtering conditions. To explore the key miRNAs in the pathogenesis of myocardial I/R injury and develop miRNA diagnostic biomarkers for myocardial I/R injury prevention, we performed a systematic analysis of publicly available myocardial I/R injury miRNA expression data and investigated the function of the signature miRNA. A total of 17 representative myocardial I/R injury miRNA datasets were extracted from the Google Scholar website and a systematic bioinformatics analysis was done. TargetScan software was used to predict the miRNA target genes, and functional enrichment and transcription factor binding analyses were performed on the target genes using the DAVID and Tfacts databases. In this study, a total of 10 signature miRNAs associated with myocardial I/R injury were identified, which included eight significantly upregulated miRNAs (miR-let-7b-3p, miR-let-7c-3p, miR-15b-3p, miR-195-3p, miR-21-5p, miR-214-5p, miR-24-3p, and miR-320a) and two significantly downregulated miRNAs (miR-126-5p and miR-499a-5p). They had different influences on myocardial I/R injury. The upregulated target gene-expressing signature messenger RNAs (mRNAs) were mainly involved in the transcriptional regulation process of GO: 0000122, negative regulation of transcription from RNA polymerase II promoter, and so on, while downregulated expression of signature mRNAs was mainly involved in GO:0070534, protein K63-linked ubiquitination, and so forth. To summarize, 10 signature miRNAs of myocardial I/R injury pathogenesis were identified and their target genes and transcription factors were revealed, suggesting the potential novel therapeutic targets for myocardial I/R injury.

Inhibition of miR-24 suppresses malignancy of human non-small cell lung cancer cells by targeting WWOX in vitro and in vivo

Background

We investigated the effect of micro‐RNA 24 (miR‐24) and WWOX on non‐small cell lung cancer (NSCLC) cell proliferation and migration in vitro and in vivo.

Methods

We performed bioinformatics analysis and 3′ untranslated region luciferase assay to investigate the direct target of miR‐24. Proliferation, apoptosis, and transwell invasion assays were employed to evaluate the effect of WWOX overexpression with pcDNA3‐WWOX and knocking down miR‐24 with miR‐24 small interfering RNA. Quantitative real‐time PCR, Western blot, and immunohistochemistry were also used to investigate miR‐24 and c‐Kit expression, and apoptosis and invasion‐related proteins. Finally, we constructed a tumor xenograft model in nude mice to confirm the effect of miR‐24 on NSCLC cell proliferation in vivo.

Results

According to our experimental data, miR‐24 inhibition could induce apoptosis by activating caspase 3 and suppress the viability and proliferation of NSCLC cells in vitro and in vivo. MiR‐24 downregulation could reduce the invasive ability of NSCLC cells by downregulating MMP9. WWOX was identified as a functional target of miR‐24. WWOX overexpression generated the same effect with antagonizing miR‐24, while blocking WWOX counteracted the tumor suppressive effect caused by miR‐24 inhibition. MiR‐24 may function as an oncogene and play an important role in the cell growth and migration of NSCLC.

Conclusions

Our findings enhance understanding of the miR‐24 regulatory network and the molecular mechanism that underlies the oncogenesis and development of NSCLC. Suppressing the effect of miR‐24 on cancer cells using a miR‐24 inhibitor may be an attractive therapeutic strategy against NSCLC.

A Polysome-Based microRNA Screen Identifies miR-24-3p as a Novel Promigratory miRNA in Mesothelioma

The expression of miRNAs in cancer has been widely studied and has allowed the definition of oncomirs and oncosuppressors. We note that it is often underestimated that many mRNAs are expressed, but translationally silent. In spite of this, systematic identification of miRNAs in equilibrium with their target mRNAs on polysomes has not been widely exploited. To identify biologically active oncomirs, we performed a screen for miRNAs acting on the polysomes of malignant mesothelioma (MPM) cells. Only a small percentage of expressed miRNAs physically associated with polysomes. On polysomes, we identified miRNAs already characterized in MPM, as well as novel ones like miR-24-3p, which acted as a promigratory miRNA in all cancer cells tested. miR-24-3p positively regulated Rho-GTP activity, and inhibition of miR-24-3p reduced growth in MPM cells. Analysis of miR-24-3p common targets, in two mesothelioma cell lines, identified a common subset of downregulated genes. These same genes were downregulated during the progression of multiple cancer types. Among the specific targets of miR-24-3p was cingulin, a tight junction protein that inhibits Rho-GTP activity. Overexpression of miR-24-3p only partially abrogated cingulin mRNA, but completely abrogated cingulin protein, confirming its action via translational repression. We suggest that miR-24-3p is an oncomir and speculate that identification of polysome-associated miRNAs efficiently sorts out biologically active miRNAs from inactive ones.Significance: Subcellular localization of miRNAs may predict their role in cancer and identify novel oncogenic miRNAs involved in cancer progression.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/20/5741/F1.large.jpg Cancer Res; 78(20); 5741-53. ©2018 AACR.

* Glioblastoma Exosomes for Therapeutic Angiogenesis in Peripheral Ischemia

Peripheral ischemia as a result of occlusive vascular disease is a widespread problem in patients older than the age of 65. Angiogenic therapies that can induce microvascular growth have great potential for providing a long-lasting solution for patients with ischemia and would provide an appealing alternative to surgical and percutaneous interventions. However, many angiogenic therapies have seen poor efficacy in clinical trials, suggesting that patients with long-term peripheral ischemia have considerable therapeutic resistance to angiogenic stimuli. Glioblastoma is one of the most angiogenic tumor types, inducing robust vessel growth in the area surrounding the tumor. One major angiogenic mechanism used by the tumor cells to induce blood vessel growth is the production of exosomes and other extracellular vesicles that can carry pro-angiogenic and immunomodulatory signals. Here, we explored whether the pro-angiogenic aspects of glioblastoma-derived exosomes could be harnessed to promote angiogenesis and healing in the context of peripheral ischemic disease. We demonstrate that the exosomes derived from glioblastoma markedly enhance endothelial cell proliferation and increase endothelial tubule formation in vitro. An analysis of the microRNA expression using next generation sequencing identified that exosomes contained a high concentration of miR-221. In addition, we found that glioblastoma exosomes contained significant amounts of the proteoglycans glypican-1 and syndecan-4, which can serve as co-receptors for angiogenic factors, including fibroblast growth factor-2 (FGF-2). In a hindlimb ischemia model in mice, we found that the exosomes promoted enhanced revascularization in comparison to control alginate gels and FGF-2 treatment alone. Taken together, our results support the fact that glioblastoma-derived exosomes have powerful effects in increasing revascularization in the context of peripheral ischemia.

miR‑24 regulates angiogenesis in gliomas

Gliomas are one of the most common and most aggressive types of central nervous system tumor. Angiogenesis is an important basis for the growth of solid tumors, including gliomas, which is regulated by microRNAs (miRNAs). However, the mechanism remains unclear. Recently, it was demonstrated that miR‑24 was upregulated in gliomas, so the aim of the present study is to establish whether the dysregulation of miR‑24 in glioma cells promotes microvascular proliferation of endothelial cells (ECs), and to investigate the potential mechanism. miR‑24 was overexpressed or downregulated in U251 glioma cell line cells using miR‑24 mimics or inhibitors, respectively. Subsequently, the effects of conditional medium from miR‑24 mimic‑ or inhibitor‑transfected U251 cells on cell viability, migration and angiogenesis of human umbilical vein ECs (HUVECs) were examined. The expression levels of vascular endothelial growth factor (VEGF) mRNA, basic fibroblast growth factor (bFGF) mRNA, epidermal growth factor (EGF) mRNA, transforming growth factor (TGF)‑β mRNA, matrix metalloproteinase (MMP)‑2 mRNA and MMP‑9 mRNA, and the mRNA and protein levels of VEGF and TGF‑β in miR‑24 mimic‑ or inhibitor‑transfected U251 cells were obtained by reverse transcription‑quantitative polymerase chain reaction and western blot analysis, respectively. The effects of conditional medium from miR‑24 mimic‑ or inhibitor‑transfected U251 cells on expression levels of VEGF mRNA, TGF‑β mRNA, MMP‑2 mRNA and MMP‑9 mRNA, and mRNA and protein expression levels of VEGF and TGF‑β, and intracellular AKT and β‑catenin signaling in HUVECs were also examined. The results indicated that the conditional medium from miR‑24 mimic‑transfected U251 cells exhibited significantly increased cell viability, cell migration and tube formation of HUVECs. By contrast, the conditional medium from miR‑24 inhibitor‑transfected U251 cells exhibited significantly decreased cell viability, cell migration and tube formation of HUVECs. Enforced expression of miR‑24 in U251 cells may promote the cell viability and angiogenesis of HUVECs. The mRNA expression levels of VEGF, bFGF, EGF, TGF‑β, MMP‑2 and MMP‑9 in U251 cells were significantly increased by miR‑24 mimics. Western blot detection confirmed the increased levels of VEGF and TGF‑β protein expression in U251 by miR‑24 mimics, and the decrease of VEGF and TGF‑β protein expression levels in U251 by miR‑24 inhibitors. The conditional medium from miR‑24 mimic‑transfected U251 cells increased the expression levels of the angiogenesis‑associated factors, including VEGF, TGF‑β, MMP‑2, and MMP‑9. By contrast, reduced expression of miR‑24 in U251 cells may downregulate the expression of those angiogenesis‑associated factors. Thus, miR‑24 in U251 cells may be important in the angiogenesis of HUVECs via VEGF and TGF‑β, and the intracellular signaling of AKT and β‑catenin may be involved in this process.

miR-24-3p/FGFR3 Signaling as a Novel Axis Is Involved in Epithelial-Mesenchymal Transition and Regulates Lung Adenocarcinoma Progression

Our previous studies showed that Fibroblast growth factor receptor 3 (FGFR3) contributed to cell growth in lung cancer. However, the correlation between FGFR3 and tumor progression, coupled with the underlying mechanisms, are not fully understood. The clinical significance of FGFR3 was determined in two cohorts of clinical samples (n = 22, n = 78). A panel of biochemical assays and functional experiments was utilized to elucidate the underlying mechanisms and effects of FGFR3 and miR-24-3p on lung adenocarcinoma progression. Upregulated FGFR3 expression indicated an adverse prognosis for lung adenocarcinoma individuals and promoted metastatic potential of lung adenocarcinoma cells. Owing to the direct regulation towards FGFR3, miR-24-3p could interfere with the potential of proliferation, migration, and invasion in lung adenocarcinoma, following variations of EMT-related protein expression. As a significant marker of EMT, E-cadherin was negatively correlated with FGFR3, of which ectopic overexpression could neutralize the antitumour effects of miR-24-3p and reverse its regulatory effects on EMT markers. Taken together, these findings define a novel insight into the miR-24-3p/FGFR3 signaling axis in regulating lung adenocarcinoma progression and suggest that targeting the miR-24-3p/FGFR3 axis could be an effective and efficient way to prevent tumor progression.

MicroRNA-876-3p functions as a tumor suppressor gene and correlates with cell metastasis in pancreatic adenocarcinoma via targeting JAG2

Dysregulation of microRNA (miRNA) expression in multiple cancers and their vital roles in malignant cancer progression are well investigated. The purpose of this study was to explore the biological roles of miR-876-3p in pancreatic cancer. We used genome-wide gene expression analysis in clinical pancreatic adenocarcinoma samples to identify miR-876-3p down-regulated in pancreatic cancer. We then collected 22 pairs of pancreatic cancer and the corresponding non-cancerous tissues to determine miR-876-3p level, and confirmed that miR-876-3p was significantly down-regulated in pancreatic cancer. Furthermore, functional analysis suggested that overexpression of miR-876-3p suppressed cell growth and aggressively increased cells apoptosis in BXPC-3 and PANC-1 cells, whereas down-regulation led to the opposite results. We identified Jagged2 (JAG2) as a direct target of miR-876-3p, and an inverse correlation between miR-876-3p and JAG2 was observed in pancreatic adenocarcinoma. Moreover, miR-876-3p and a JAG2 siRNA were co-transfected into both PANC-1 and BXPC-3 cells to explore the mechanism of miR-876-3p and JAG2 on pancreatic adenocarcinoma tumorigenesis. Down-regulation of JAG2 inhibited the overexpression effects of miR-876-3p, and up-regulation of JAG2 reversed the effects of overexpressed miR-876-3p. Cumulatively, these results revealed a significant role of the miR-876-3p/JAG2 axis in suppressing pancreatic adenocarcinoma cell growth and aggressiveness.

MicroRNA-155 promotes gastric cancer growth and invasion by negatively regulating transforming growth factor-β receptor 2

Gastric cancer (GC) is one of the most common malignancies worldwide and has high morbidity and mortality rates. It is essential to elucidate the molecular events of GC proliferation and invasion, which will provide new therapeutic targets for GC. The inactivation of transforming growth factor-β receptor 2 (TGFβR2) correlates with cancer cell growth and metastasis, but the mechanisms underlying the downregulation of TGFβR2 expression remain unknown. MicroRNAs (miRNAs) act as post-transcriptional regulators and play a key role in the development of cancers. Bioinformatics analysis and luciferase reporter assays have shown that miR-155 directly binds to the 3'-UTR of TGFβR2 mRNA. In this study, we found that the TGFβR2 protein levels, but not mRNA levels, were downregulated in GC tissues, and the levels of miR-155 were significantly increased in GC tissues. We deduced that miR-155 was inversely correlated with TGFβR2 in GC cells. In vitro studies showed that overexpression of miR-155 in SGC7901 inhibited the expression of TGFβR2 and then promoted GC cell proliferation and migration, whereas miR-155 inhibitor showed opposite effects. In addition, the tumor-suppressing function of TGFβR2 was verified by using siRNA and TGFβR2 overexpressing plasmids. The results showed that miR-155 promotes cell growth and migration by negatively regulating TGFβR2. Thus, miR-155-regulated TGFβR2 as a potential therapeutic target in GC.

Onco-miR-130 promotes cell proliferation and migration by targeting TGFβR2 in gastric cancer

MicroRNAs (miRNAs) have been proved to play crucial roles in tumorigenesis. TGFβ signal pathway abnormality is found in various cancers and correlates with tumor proliferation and metastasis. However, the mechanisms underlying the dys-regulation of TGFβR2 expression in GC have not been investigated yet. In this study, we found that the TGFβR2 protein was clearly repressed in tumor tissues, while miR-130 expression level was dramatically increased in GC tissues. Firefly luciferase activity assay revealed that miR-130 could directly bind to 3′UTR of TGFβR2 mRNA. Meanwhile, miR-130 mimics lead to the decreased TGFβR2 protein levels, while miR-130 inhibitors enhanced TGFβR2 expression in SGC7901 cells. Subsequent functional experiments showed that overexpressed miR-130 could promote proliferation and migration of SGC7901 cells. And siRNA-mediated TGFβR2 down-regulation could simulate the effects of miR-130 mimics on phenotypes of SGC7901 cells. Furthermore, there existed intense relationship between the expression level of miR-130 and epithelial-mesenchymal markers. Our results demonstrated that miR-130 was an oncogene by directly targeting TGFβR2 in GC.

Mir-24 regulates hepatocyte apoptosis via BIM during acute liver failure

Acuteliver failure (ALF) has a high mortality rate and is characterized by massive hepatocyte destruction. Although microRNAs (miRNAs) play an important role in manyliver diseases, the role of miRNAs in ALF development is unknown. In this study, the murine ALF model was induced by intraperitoneal injection of D-galactosamine/lipopolysaccharide (D-GalN/LPS). Compared with saline-treated mice, miR-24 was distinctly down-regulated post D-GalN/LPS challenge in vivo and D-galactosamine/tumor necrosis factor (D-GalN/TNF) challenge in vitro, which was confirmed by quantitative real-time polymerase chain reaction. Meanwhile, the mRNA and protein levels of the BH3-only-domain-containing protein BIM were upregulated after challenge both in vivo and in vitro. Previous studies have demonstrated that hepatocyte apoptosis is a distinguishing feature of D-GalN/LPS-associated liver failure. In this study, D-GalN/LPS-challenged mice showed higher alanine aminotransferase and aspartate aminotransferase levels, more severe liver damage, increased numbers of apoptotic hepatocytes and higher levels of caspase-3 compared with saline-treated mice. In D-GalN/TNF-treated BNLCL2 cells, miR-24 overexpression attenuated apoptosis.Furthermore, miR-24 overexpression reduced BIM mRNA and protein levels in vitro. Taken together, these findings demonstrate that miR-24 regulates hepatocyte apoptosis via BIM during ALF development, suggesting that miR-24 is a novel onco-miRNA that may provide potential therapeutic targets for ALF.

Bim gene dosage is critical in modulating nephron progenitor survival in the absence of microRNAs during kidney development

Low nephron endowment at birth has been associated with an increased risk for developing hypertension and chronic kidney disease. We demonstrated in an earlier study that conditional deletion of the microRNA (miRNA)-processing enzyme Dicer from nephron progenitors results in premature depletion of the progenitors and increased expression of the proapoptotic protein Bim (also known as Bcl-2L11). In this study, we generated a compound mouse model with conditional deletion of both Dicer and Bim, to determine the biologic significance of increased Bim expression in Dicer-deficient nephron progenitors. The loss of Bim partially restored the number of nephron progenitors and improved nephron formation. The number of progenitors undergoing apoptosis was significantly reduced in kidneys with loss of a single allele, or both alleles, of Bim compared to mutant kidneys. Furthermore, 2 miRNAs expressed in nephron progenitors (miR-17 and miR-106b) regulated Bim levels in vitro and in vivo Together, these data suggest that miRNA-mediated regulation of Bim controls nephron progenitor survival during nephrogenesis, as one potential means of regulating nephron endowment.-Cerqueira, D. M., Bodnar, A. J., Phua, Y. L., Freer, R., Hemker, S. L., Walensky, L. D., Hukriede, N. A., Ho, J. Bim gene dosage is critical in modulating nephron progenitor survival in the absence of microRNAs during kidney development.

A Review of the Scaffold Protein Menin and its Role in Hepatobiliary Pathology

Multiple endocrine neoplasia type 1 (MEN1) is a familial cancer syndrome with neuroendocrine tumorigenesis of the parathyroid glands, pituitary gland, and pancreatic islet cells. The MEN1 gene codes for the canonical tumor suppressor protein, menin. Its protein structure has recently been crystallized, and it has been investigated in a multitude of other tissues. In this review, we summarize recent advancements in understanding the structure of the menin protein and its function as a scaffold protein in histone modification and epigenetic gene regulation. Furthermore, we explore its role in hepatobiliary autoimmune diseases, cancers, and metabolic diseases. In particular, we discuss how menin expression and function are regulated by extracellular signaling factors and nuclear receptor activation in various hepatic cell types. How the many signaling pathways and tissue types affect menin's diverse functions is not fully understood. We show that small-molecule inhibitors affecting menin function can shed light on menin's broad role in pathophysiology and elucidate distinct menin-dependent processes. This review reveals menin's often dichotomous function through analysis of its role in multiple disease processes and could potentially lead to novel small-molecule therapies in the treatment of cholangiocarcinoma or biliary autoimmune diseases.

ING5 suppresses breast cancer progression and is regulated by miR-24

Background

The inhibitor of growth (ING) gene family of tumor suppressors is involved in multiple cellular functions such as cell cycle regulation, apoptosis, and chromatin remodeling. ING5 is a new member of the ING family whose function and regulation remain largely unknown.

Methods

Quantitative real-time PCR and western blot were used to examine the expression levels of ING5 in breast cancer tissues. The miRNAs that potentially targeted ING5 were determined by bioinformatics analysis and luciferase reporter assay. Cell viability assay, transwell invasion and apoptosis assay were used to characterize the changes induced by overexpressing or knocking down miR-24 or ING5. Hematoxylin and eosin (H&E) staining and immunohistochemical staining for ING5 and Ki-67 were used for xenograft assays in BALB/c nude mice.

Results

We showed that the ING5 protein rather than the mRNA, was significantly downregulated in breast cancer tissues. We also investigated the potential function of ING5 in breast tumorigenesis and found that ING5 suppressed the proliferation and invasion of breast cancer cells and promoted their apoptosis. Furthermore, we explored the molecular mechanisms accounting for the dysregulation of ING5 in breast cancer cells and identified an oncomiR, miR-24, as a direct upstream regulator of ING5. We revealed that miR-24 had the opposite effects to those of ING5 on breast cancer cells and could accelerate xenografted tumor growth in vivo.

Conclusion

Our findings uncover the tumor-suppressive role of ING5 and the regulatory pathway of ING5 in breast cancer and may provide insights into the molecular mechanisms of breast carcinogenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-017-0658-z) contains supplementary material, which is available to authorized users.

miR-24-3p Is Overexpressed in Hodgkin Lymphoma and Protects Hodgkin and Reed-Sternberg Cells from Apoptosis

miRNAs play important roles in biological processes, such as proliferation, metabolism, differentiation, and apoptosis, whereas altered expression levels contribute to diseases, such as cancers. We identified miRNAs with aberrant expression in Hodgkin lymphoma (HL) and investigated their role in pathogenesis. Small RNA sequencing revealed 84 significantly differentially expressed miRNAs in HL cell lines as compared to germinal center B cells. Three up-regulated miRNAs-miR-23a-3p, miR-24-3p, and miR-27a-3p-were derived from one primary miRNA transcript. Loss-of-function analyses for these miRNAs and their seed family members resulted in decreased growth on miR-24-3p inhibition in three HL cell lines and of miR-27a/b-3p inhibition in one HL cell line. Apoptosis analysis indicated that the effect of miR-24-3p on cell growth is at least in part caused by an increase of apoptotic cells. Argonaute 2 immunoprecipitation revealed 1142 genes consistently targeted by miRNAs in at least three of four HL cell lines. Furthermore, 52 of the 1142 genes were predicted targets of miR-24-3p. Functional annotation analysis revealed a function related to cell growth, cell death, and/or apoptosis for 15 of the 52 genes. Western blotting of the top five genes showed increased protein levels on miR-24-3p inhibition for CDKN1B/P27^kip1 and MYC. In summary, we showed that miR-24-3p is up-regulated in HL and its inhibition impairs cell growth possibly via targeting CDKN1B/P27^kip1 and MYC.

Loss of GCN5 leads to increased neuronal apoptosis by upregulating E2F1- and Egr-1-dependent BH3-only protein Bim

Cellular acetylation homeostasis is a kinetic balance precisely controlled by histone acetyl-transferase (HAT) and histone deacetylase (HDAC) activities. The loss of the counterbalancing function of basal HAT activity alters the precious HAT:HDAC balance towards enhanced histone deacetylation, resulting in a loss of acetylation homeostasis, which is closely associated with neuronal apoptosis. However, the critical HAT member whose activity loss contributes to neuronal apoptosis remains to be identified. In this study, we found that inactivation of GCN5 by either pharmacological inhibitors, such as CPTH2 and MB-3, or by inactivation with siRNAs leads to a typical apoptosis in cultured cerebellar granule neurons. Mechanistically, the BH3-only protein Bim is transcriptionally upregulated by activated Egr-1 and E2F1 and mediates apoptosis following GCN5 inhibition. Furthermore, in the activity withdrawal- or glutamate-evoked neuronal apoptosis models, GCN5 loses its activity, in contrast to Bim induction. Adenovirus-mediated overexpression of GCN5 suppresses Bim induction and apoptosis. Interestingly, the loss of GCN5 activity and the induction of Egr-1, E2F1 and Bim are involved in the early brain injury (EBI) following subarachnoid haemorrhage (SAH) in rats. HDAC inhibition not only significantly rescues Bim expression and apoptosis induced by either potassium deprivation or GCN5 inactivation but also ameliorates these events and EBI in SAH rats. Taken together, our results highlight a new mechanism by which the loss of GCN5 activity promotes neuronal apoptosis through the transcriptional upregulation of Bim, which is probably a critical event in triggering neuronal death when cellular acetylation homeostasis is impaired.

miR-24 Inhibition Increases Menin Expression and Decreases Cholangiocarcinoma Proliferation

Menin (MEN1) is a tumor-suppressor protein in neuroendocrine tissue. Therefore, we tested the novel hypothesis that menin regulates cholangiocarcinoma proliferation. Menin and miR-24 expression levels were measured in the following intrahepatic and extrahepatic cholangiocarcinoma (CCA) cell lines, Mz-ChA-1, TFK-1, SG231, CCLP, HuCCT-1, and HuH-28, as well as the nonmalignant human intrahepatic biliary line, H69. miR-24 miRNA and menin protein levels were manipulated in vitro in Mz-ChA-1 cell lines. Markers of proliferation and angiogenesis (Ki-67, vascular endothelial growth factors A/C, vascular endothelial growth factor receptors 2/3, angiopoietin 1/2, and angiopoietin receptors 1/2) were evaluated. Mz-ChA-1 cells were injected into the flanks of nude mice and treated with miR-24 inhibitor or inhibitor scramble. Menin expression was decreased in advanced CCA specimens, whereas miR-24 expression was increased in CCA. Menin overexpression decreased proliferation, angiogenesis, migration, and invasion. Inhibition of miR-24 increased menin protein expression while decreasing proliferation, angiogenesis, migration, and invasion. miR-24 was shown to negatively regulate menin expression by luciferase assay. Tumor burden and expression of proliferative and angiogenic markers was decreased in the miR-24 inhibited tumor group compared to controls. Interestingly, treated tumors were more fibrotic than the control group. miR-24-dependent expression of menin may be important in the regulation of nonmalignant and CCA proliferation and may be an additional therapeutic tool for managing CCA progression.

miR-24 promotes the proliferation, migration and invasion in human tongue squamous cell carcinoma by targeting FBXW7

Recent studies suggest that aberrant expression of miR-24 is linked to various human cancers, including tongue squamous cell carcinoma (TSCC). F-box and WD-40 domain protein 7 (FBXW7), a tumor-suppressor gene, is responsible for the degradation of several proto-oncogenes. However, the function and mechanism of miR-24 and FBXW7 in TSCC remains unclear. In the present study, we found that miR-24 was increased in TSCC tissues and cell lines, and that upregulation of miR-24 was associated with advanced clinical stage and a shorter overall survival of TSCC patients. Inhibition of miR-24 significantly suppressed the proliferation, migration and invasion of TSCC cells in vitro. Furthermore, miR-24 repressed FBXW7 expression by directly binding to the 3-untranslated region of FBXW7. Moreover, the suppression of FBXW7 increased the proliferation, migration and invasion of TSCC cells, and the restoration of FBXW7 substantially attenuated the oncogenic effects of miR-24. In conclusion, our results demonstrated that upregulation of miR-24 was associated with tumor progression and poor prognosis in TSCC patients, and that overexpression of miR-24 was correlated with the proliferation, migration and invasion of TSCC cells in vitro, at least partially through regulation of its functional target FBXW7. Thus, miR-24 may serve as a novel potential biomarker for the prognosis of TSCC patients.

Targeted Silencing of S100A8 Gene by miR-24 to Increase Chemotherapy Sensitivity of Endometrial Carcinoma Cells to Paclitaxel

Background

The objective of this study was to determine whether miR-24 can regulate malignant proliferation and chemotherapy sensitivity of EC cells by targeted silencing of the S100 Calcium Binding Protein A8 (S100A8) gene.

Material/Methods

The expression of miR-24 in EC tissues was detected by quantitative real-time PCR. The proliferation ability and chemotherapy sensitivity were analyzed by MTT assay. Bioinformatics software was used to predict some potential target genes of miR-24. Luciferase activity assay was used to verify the relationship between target genes and miR-24. S100A8 protein expression was detected by Western blot analysis.

Results

The low expression of miR-24 in EC tissues compared with normal control tissues suggests miR-24 might play a role in tumorigenesis of EC. EC HEC-1A cells were transfected with miR-24 agonist (agomiR-24) to up-regulate the expression of miR-24. Up-regulation of miR-24 inhibited the cell proliferation and advanced the chemotherapy sensitivity to paclitaxel in HEC-1A cells significantly. We used several types of bioinformatic software to predict that miR-24 could specifically combine with the 3′ untranslated region (3′UTR) of the S100A8 gene, and this prediction was verified by Western blot and luciferase activities assay. The regulation effects of miR-24 enhancement on cell proliferation and chemotherapy sensitivity were largely reversed by S100A8 up-regulation.

Conclusions

miR-24 acts as a tumor-suppressing gene to inhibit malignant proliferation and advance chemotherapy sensitivity to paclitaxel in EC by targeted silencing of the S100A8 gene.