The promise of microRNA replacement therapy

Amyotrophic lateral sclerosis: mechanisms and therapeutics in the epigenomic era

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of the motor neurons, which results in weakness and atrophy of voluntary skeletal muscles. Treatments do not modify the disease trajectory effectively, and only modestly improve survival. A complex interaction between genes, environmental exposure and impaired molecular pathways contributes to pathology in patients with ALS. Epigenetic mechanisms control the hereditary and reversible regulation of gene expression without altering the basic genetic code. Aberrant epigenetic patterns-including abnormal microRNA (miRNA) biogenesis and function, DNA modifications, histone remodeling, and RNA editing-are acquired throughout life and are influenced by environmental factors. Thus, understanding the molecular processes that lead to epigenetic dysregulation in patients with ALS might facilitate the discovery of novel therapeutic targets and biomarkers that could reduce diagnostic delay. These achievements could prove crucial for successful disease modification in patients with ALS. We review the latest findings regarding the role of miRNA modifications and other epigenetic mechanisms in ALS, and discuss their potential as therapeutic targets.

miR-218 inhibits the migration and invasion of glioma U87 cells through the Slit2-Robo1 pathway

Malignant gliomas are the most common primary brain tumors in adults and are associated with the highest mortality rate. Glioma invasion is one of the most notable causes of the poor prognosis of this cancer. Preventing the invasive behavior of malignant glioma cells by altering effector molecules can significantly improve the prognosis of a patient. microRNAs (miRNAs) are small noncoding RNAs, ~22 nucleotides in length, that are able to function as oncogenes or tumor suppressors in human cancer. In the present study, the expression level of miRNA 218 (miR-218) was found to be markedly downregulated in glioma cell lines and human primary glioma tissues. miR-218 upregulation was found to dramatically reduce the migratory speed and invasive ability of glioma cells. Furthermore, it was demonstrated that ectopic expression of miR-218 in glioma cells resulted in the downregulation of roundabout, axon guidance receptor, homolog 1 (Robo1), upregulation of Slit homolog 2 (Slit2) and the expression of associated proteins following Robo1 knockdown by small interfering RNA. In addition, it was demonstrated that miR-218 inactivated the Slit2-Robo1 pathway through downregulating Robo1 expression by directly targeting the 3'-untranslated region (3'-UTR) of Robo1. The present results indicate that miR-218 plays important roles in preventing the invasiveness of glioma cells, and reveals a novel mechanism of miRNA-mediated direct suppression of the Slit2-Robo1 pathway in glioma.

MicroRNAs: new players in IBD

MicroRNAs (miRNAs) are small non-coding RNAs, 18-23 nucleotides long, which act as post-transcriptional regulators of gene expression. miRNAs are strongly implicated in the pathogenesis of many common diseases, including IBDs. This review aims to outline the history, biogenesis and regulation of miRNAs. The role of miRNAs in the development and regulation of the innate and adaptive immune system is discussed, with a particular focus on mechanisms pertinent to IBD and the potential translational applications.

Microsatellite instability: an update

Deficient DNA mismatch repair (MMR) results in a strong mutator phenotype known as microsatellite instability (MSI), which is a hallmark of Lynch syndrome-associated cancers. MSI is characterized by length alterations within simple repeated sequences that are called microsatellites. Lynch syndrome is primarily caused by mutations in the MMR genes, mainly MLH1 and MSH2, and less frequently in MSH6, and rarely PMS2, and large genomic rearrangements account for 5-20 % of all mutations. Germ line hemiallelic methylations of MLH1 or MSH2 are termed as epimutations and have been identified as causative of Lynch syndrome. Moreover, germ line 3' deletions of EPCAM gene is involved in MSH2 methylation. MSI is also observed in about 15 % of sporadic colorectal cancer (CRC), gastric cancer (GC), and endometrial cancer (EC), and at lower frequencies in other cancers, often in association with hypermethylation of the MLH1 gene. Trimethylation of histone H3 on Lys36 (H3K36 me3) is an epigenetic histone mark that was required for DNA MMR in vivo. Thus, mutations in the H3K36 trimethyltransferase SETD2 have been reported as a potential cause of MSI. Genetic, epigenetic, and transcriptomic differences have been identified between cancers with and without MSI. Recent comprehensive molecular characterizations of CRC, EC, and GC by The Cancer Genome Atlas indicate that MSI+ cancers are distinct biological entities. The BRAF V600E mutation is specifically associated with sporadic MSI+ CRCs with methylated MLH1, but is not associated with Lynch syndrome-related CRCs. Accumulating evidence indicates a role of interactions between MSI and microRNA (miRNA) in the pathogenesis of MSI-positive (MSI+) cancer. As another new mechanism underlying MSI, overexpression of miR-155 or miR-21 has been shown to downregulate the expression of the MMR genes. Gene targets of frameshift mutations caused by MSI are involved in various cellular functions, including DNA repair (MSH3 and MSH6), cell signaling (TGFBR2 and ACVR2A), apoptosis (BAX), epigenetic regulation (HDAC2 and ARID1A), and miRNA processing (TARBP2 and XPO5), and a subset of MSI+ CRCs reportedly shows the mutated miRNA machinery phenotype. Moreover, microsatellite repeats in miRNA genes, such as hsa-miR-1273c, may be novel MSI targets for CRC, and mutations in noncoding regulatory regions of MRE11, BAX (BaxΔ2), and HSP110 (HSP110ΔE9) may affect the efficiency of chemotherapy. Thus, analyses of MSI and its related molecular alterations in cancers are increasingly relevant in clinical settings, and MSI is a useful screening marker for identifying patients with Lynch syndrome and a prognostic factor for chemotherapeutic interventions. In this review, we summarize recent advances in the pathogenesis of MSI and focus on genome-wide analyses that indicate the potential use of MSI and related alterations as biomarkers and novel therapeutic targets.

MicroRNA as tools and therapeutics in lung cancer

Lung cancer is the number one cause of cancer related deaths. The lack of specific and accurate tools for early diagnosis and minimal targeted therapeutics both contribute to poor outcomes. The recent discovery of microRNAs (miRNAs) revealed a novel mechanism for post-transcriptional regulation in cancer and has created new opportunities for the development of diagnostics, prognostics and targeted therapeutics. In lung cancer, miRNA expression profiles distinguish histological subtypes, predict chemotherapeutic response and are associated with prognosis, metastasis and survival. Furthermore, miRNAs circulate in body fluids and hence may serve as important biomarkers for early diagnosis or stratify patients for personalized therapeutic strategies. Here, we provide an overview of the miRNAs implicated in lung cancer, with an emphasis on their clinical utility.

Targeting microRNAs in epithelial-to-mesenchymal transition-induced cancer stem cells: therapeutic approaches in cancer

INTRODUCTION

Epithelial-to-mesenchymal transition (EMT) is a pathological phenomenon of cancer that confers tumor cells with increased cell motility, invasive and metastatic abilities with the acquisition of 'cancer stem-like cell' (CSC) phenotype. EMT endows tumor cells with intrinsic/acquired resistant phenotype at achievable doses of anticancer drugs and leads to tumor recurrence and progression. Besides the complex network of signaling pathways, microRNAs (miRNAs) are being evolved as a new player in the induction and regulation of EMT.

AREAS COVERED

In this review article, the author has searched the PubMed and Google Scholar electronic databases for original research and review articles to gather current information on the association of EMT-induced CSCs with therapeutic resistance, tumor growth and metastasis, which are believed to be regulated by certain miRNAs.

EXPERT OPINION

This review outlines not only the perspective on selective targeting of EMT-induced CSCs through altered expression of novel miRNAs and/or the use of conventional drugs that affect the levels of critical miRNAs but also the strategies on overcoming the drug resistance by interfering with EMT and modulating its associated pathways in CSCs that can be considered as potential therapeutic approaches toward eradicating the tumor recurrence and metastasis.

Combination treatment with doxorubicin and microRNA-21 inhibitor synergistically augments anticancer activity through upregulation of tumor suppressing genes

Doxorubicin (DOX) is a key chemotherapeutic drug for cancer treatment. The antitumor mechanism of DOX is its action as a topoisomerase II poison by preventing DNA replication. Our study shows that DOX can be involved in epigenetic regulation of gene transcription through downregulation of DNA methyltransferase 1 (DNMT1) then reactivation of DNA methylation-silenced tumor suppressor genes in glioblastoma (GBM). Recent evidence demonstrated that microRNA (miR or miRNA) can mediate expression of genes through post-transcriptional regulation and modulate sensitivity to anticancer drugs. As one of the first miRNAs detected in the human genome, miR-21 has been validated to be overexpressed in GBM. Combination treatment of a chemotherapeutic and miRNA showed synergistically increased anticancer activities which has been proven to be an effective strategy for tumor therapy. In our study, co-treatment of DOX and miR-21 inhibitor (miR-21i) resulted in remarkably increased expression of tumor suppressor genes compared with DOX or the miR-21i treatment alone. Moreover, we demonstrate that combining DOX and miR-21i significantly reduced tumor cell proliferation, invasion and migration in vitro. Our study concludes that combining DOX and miR-21i is a new strategy for the therapy of GBM.

MAPK and JAK/STAT pathways targeted by miR-23a and miR-23b in prostate cancer: computational and in vitro approaches

The long-lasting inadequacy of existing treatments for prostate cancer has led to increasing efforts for developing novel therapies for this disease. MicroRNAs (miRNAs) are believed to have considerable therapeutic potential due to their role in regulating gene expression and cellular pathways. Identifying miRNAs that efficiently target genes and pathways is a key step in using these molecules for therapeutic purposes. Moreover, computational methods have been devised to help identify candidate miRNAs for each gene/pathway. MAPK and JAK/STAT pathways are known to have essential roles in cell proliferation and neoplastic transformation in different cancers including prostate cancer. Herein, we tried to identify miRNAs that target these pathways in the context of prostate cancer as therapeutic molecules. Genes involved in these pathways were analyzed with various algorithms to identify potentially targeting miRNAs. miR-23a and miR-23b were then selected as the best potential candidates that target a higher number of genes in these pathways with greater predictive scores. We then analyzed the expression of candidate miRNAs in LNCAP and PC3 cell lines as well as prostate cancer clinical samples. miR-23a and miR-23b showed a significant downregulation in cell line and tissue samples, a finding which is consistent with overactivation of these pathways in prostate cancer. In addition, we overexpressed miR-23a and miR-23b in LNCAP and PC3 cell lines, and these two miRNAs decreased IL-6R expression which has a critical role in these pathways. These results suggest the probability of utilizing miR-23a and miR-23b as therapeutic targets for the treatment of prostate cancer.

Enrichment of A Rare Subpopulation of miR-302-Expressing Glioma Cells by Serum Deprivation

Objective

MiR-302-367 is a cluster of polycistronic microRNAs that are exclusively expressed in embryonic stem (ES) cells. The miR-302-367 promoter is functional during embryonic development but is turned off in later stages. Motivated by the cancer stem cell hypothesis, we explored the potential expression of miR-302 in brain tumor cell lines.

Materials and Methods

In the present experimental study, we have tried to expand our knowledge on the expression pattern and functionality of miR302 cluster by quantifying its expression in a series of glioma (A-172, 1321N1, U87MG) and medulloblastoma (DAOY) cell lines. To further assess the functionality of miR-302 in these cell lines, we cloned its promoter core region upstream of the enhanced green fluorescent protein (EGFP) or luciferase encoding genes.

Results

Our data demonstrated a very low expression of miR-302 in glioma cell lines, compared with that of embryonal carcinoma cell line NT2 being used as a positive control. The expression of miR-302 promoter-EGFP construct in the aforementioned cell lines demonstrated GFP expression in a rare subpopulation of the cells. Serum deprivation led to the generation of tumorospheres, enrichment of miR-302 positive cells and upregulation of a number of pluripotency genes.

Conclusion

Taken together, our data suggest that miR-302 could potentially be used as a novel putative cancer stem cell marker to identify and target cancer stem cells within tumor tissues.

MicroRNAs Used in Combination with Anti-Cancer Treatments Can Enhance Therapy Efficacy

MicroRNAs (miRNAs), a recently discovered class of small non-coding RNAs, constitute a promising approach to anti-cancer treatments when they are used in combination with other agents. MiRNAs are evolutionarily conserved non-coding RNAs that negatively regulate gene expression by binding to the complementary sequence in the 3'-untranslated region (UTR) of target genes. MiRNAs typically suppress gene expression by direct association with target transcripts, thus decreasing the expression levels of target proteins. The delivery to cells of synthetic miRNAs that mimic endogenous miRNA targeting genes involved in the DNA-Damage Response (DDR) can perturb the process, making cells more sensitive to chemotherapy or radiotherapy. This review examines how cells respond to combined therapy and it provides insights into the role of miRNAs in targeting the DDR repair pathway when they are used in combination with chemical compounds or ionizing radiation to enhance cellular sensitivity to treatments.

A qRT-PCR Method for Determining the Biodistribution Profile of a miR-34a Mimic

MRX34 has recently entered the clinic as the first therapeutic product based on a microRNA (miRNA) mimic. In order to measure drug concentrations in vivo, a quantitation method is needed that exhibits high precision, accuracy, and robustness. While most clinical applications for oligonucleotide therapeutics involve methods based on hybridization assays and liquid chromatography-tandem mass spectrometry, quantitative PCR (qPCR) is a less well-described approach. Here, we present an RT, qPCR, and analysis method to determine the tissue biodistribution of endogenous as well as a therapeutic, exogenous miRNA mimic therapeutic. Assay performance is demonstrated on multiple tissues from nonhuman primates dosed with MRX34.

MicroRNA and cancer--a brief overview

MicroRNAs (miRNAs) are short non-coding RNAs with a length of ∼22 nucleotides, involved in posttranscriptional regulation of gene expression. Until now, over 2588 miRNAs have been identified in humans and the list is growing. MicroRNAs have an important role in all biological processes and aberrant miRNA expression is associated with many diseases including cancer. In the year 2002 the first connection between cancer and miRNA deregulation was discovered. Since then, a lot of information about the key role which miRNAs play in cancer development and drug resistance has been gained. However, there is still a long way to go to fully understand the miRNA world. In this review, we briefly describe miRNA biogenesis and discuss the role of miRNAs in cancer development and drug resistance. Finally we explain how miRNAs can be used as biomarkers and as a novel therapeutic approach in cancer.

Porous PLGA microparticles to encapsulate doxorubicin and polyethylenimine/miR-34a for inhibiting the proliferation and migration of lung cancer

Porous PLGA microparticles were successfully prepared for achieving the co-delivery of doxorubicin and PEI25K/miR-34a, using ammonium bicarbonate as a porogen.

Recent progress in microRNA delivery for cancer therapy by non-viral synthetic vectors

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression. Because of significant changes in their expression in cancer, miRNAs are believed to be key factors in cancer genetics and to have potential as anticancer drugs. However, the delivery of miRNAs is limited by many barriers, such as low cellular uptake, immunogenicity, renal clearance, degradation by nucleases, elimination by phagocytic immune cells, poor endosomal release, and untoward side effects. Nonviral delivery systems have been developed to overcome these obstacles. In this review, we provide insights into the development of non-viral synthetic miRNA vectors and the promise of miRNA-based anticancer therapies, including therapeutic applications of miRNAs, challenges of vector design to overcome the delivery obstacles, and the development of miRNA delivery systems for cancer therapy. Additionally, we highlight some representative examples that give a glimpse into the current trends into the design and application of efficient synthetic systems for miRNA delivery. Overall, a better understanding of the rational design of miRNA delivery systems will promote their translation into effective clinical treatments.

miRNAs in pancreatic cancer: therapeutic potential, delivery challenges and strategies

Pancreatic ductal adenocarcinoma (PDAC) is a severe pancreatic malignancy and is predicted to victimize 1.5% of men and women during their lifetime (Cancer statistics: SEER stat fact sheet, National Cancer Institute, 2014). miRNAs have emerged as a promising prognostic, diagnostic and therapeutic tool to fight against pancreatic cancer. miRNAs could modulate gene expression by imperfect base-pairing with target mRNA and hence provide means to fine-tune multiple genes simultaneously and alter various signaling pathways associated with the disease. This exceptional miRNA feature has provided a paradigm shift from the conventional one drug one target concept to one drug multiple target theory. However, in vivo miRNA delivery is not fully realized due to challenges posed by this special class of therapeutic molecules, which involves thorough understanding of the biogenesis and physicochemical properties of miRNA and delivery carriers along with the pathophysiology of the PDAC. This review highlights the delivery strategies of miRNA modulators (mimic/inhibitor) in cancer with special emphasis on PDAC since successful delivery of miRNA in vivo constitutes the major challenge in clinical translation of this promising class of therapeutics.

A novel collagen-nanohydroxyapatite microRNA-activated scaffold for tissue engineering applications capable of efficient delivery of both miR-mimics and antagomiRs to human mesenchymal stem cells

Manipulation of gene expression through the use of microRNAs (miRNAs) offers tremendous potential for the field of tissue engineering. However, the lack of sufficient site-specific and bioactive delivery systems has severely hampered the clinical translation of miRNA-based therapies. In this study, we developed a novel non-viral bioactive delivery platform for miRNA mimics and antagomiRs to allow for a vast range of therapeutic applications. By combining nanohydroxyapatite (nHA) particles with reporter miRNAs (nanomiRs) and collagen-nanohydroxyapatite scaffolds, this work introduces the first non-viral, non-lipid platform to date, capable of efficient delivery of mature miRNA molecules to human mesenchymal stem cells (hMSCs), a particularly difficult cell type to transfect effectively, with minimal treatment-associated cytotoxicity. Firstly, miRNAs were successfully delivered to hMSCs in monolayer, with internalisation efficiencies of 17.4 and 39.6% for nanomiR-mimics and nanoantagomiRs respectively, and both nanomiR-mimics and nanoantagomiRs yielded sustained interfering activity of greater than 90% in monolayer over 7 days. When applied to 3D scaffolds, significant RNA interference of 20% for nanomiR-mimics and 88.4% for nanoantagomiRs was achieved with no cytotoxicity issues over a 7 day period. In summary, in-house synthesised non-viral nHA particles efficiently delivered reporter miRNAs both in monolayer and on scaffolds demonstrating the immense potential of this innovative miRNA-activated scaffold system for tissue engineering applications.

Epigenetic targets for novel therapies of lung diseases

In spite of substantial advances in defining the immunobiology and function of structural cells in lung diseases there is still insufficient knowledge to develop fundamentally new classes of drugs to treat many lung diseases. For example, there is a compelling need for new therapeutic approaches to address severe persistent asthma that is insensitive to inhaled corticosteroids. Although the prevalence of steroid-resistant asthma is 5-10%, severe asthmatics require a disproportionate level of health care spending and constitute a majority of fatal asthma episodes. None of the established drug therapies including long-acting beta agonists or inhaled corticosteroids reverse established airway remodeling. Obstructive airways remodeling in patients with chronic obstructive pulmonary disease (COPD), restrictive remodeling in idiopathic pulmonary fibrosis (IPF) and occlusive vascular remodeling in pulmonary hypertension are similarly unresponsive to current drug therapy. Therefore, drugs are needed to achieve long-acting suppression and reversal of pathological airway and vascular remodeling. Novel drug classes are emerging from advances in epigenetics. Novel mechanisms are emerging by which cells adapt to environmental cues, which include changes in DNA methylation, histone modifications and regulation of transcription and translation by noncoding RNAs. In this review we will summarize current epigenetic approaches being applied to preclinical drug development addressing important therapeutic challenges in lung diseases. These challenges are being addressed by advances in lung delivery of oligonucleotides and small molecules that modify the histone code, DNA methylation patterns and miRNA function.

YM500v2: a small RNA sequencing (smRNA-seq) database for human cancer miRNome research

We previously presented YM500, which is an integrated database for miRNA quantification, isomiR identification, arm switching discovery and novel miRNA prediction from 468 human smRNA-seq datasets. Here in this updated YM500v2 database (http://ngs.ym.edu.tw/ym500/), we focus on the cancer miRNome to make the database more disease-orientated. New miRNA-related algorithms developed after YM500 were included in YM500v2, and, more significantly, more than 8000 cancer-related smRNA-seq datasets (including those of primary tumors, paired normal tissues, PBMC, recurrent tumors, and metastatic tumors) were incorporated into YM500v2. Novel miRNAs (miRNAs not included in the miRBase R21) were not only predicted by three independent algorithms but also cleaned by a new in silico filtration strategy and validated by wetlab data such as Cross-Linked ImmunoPrecipitation sequencing (CLIP-seq) to reduce the false-positive rate. A new function 'Meta-analysis' is additionally provided for allowing users to identify real-time differentially expressed miRNAs and arm-switching events according to customer-defined sample groups and dozens of clinical criteria tidying up by proficient clinicians. Cancer miRNAs identified hold the potential for both basic research and biotech applications.

New insights into lung development and diseases: the role of microRNAs

MicroRNAs (miRNAs) are short endogenous noncoding RNA molecules (∼ 22 nucleotides) that can regulate gene expression at the post-transcription level. Research interest in the role of miRNAs in lung biology is emerging. MiRNAs have been implicated in a range of processes such as development, homeostasis, and inflammatory diseases in lung tissues and are capable of inducing differentiation, morphogenesis, and apoptosis. In recent years, several studies have reported that miRNAs are differentially regulated in lung development and lung diseases in response to epigenetic changes, providing new insights for their versatile role in various physiological and pathological processes in the lung. In this review, we discuss the contribution of miRNAs to lung development and diseases and possible future implications in the field of lung biology.

Survivin-targeting Artificial MicroRNAs Mediated by Adenovirus Suppress Tumor Activity in Cancer Cells and Xenograft Models

Survivin is highly expressed in most human tumors and fetal tissue, and absent in terminally differentiated cells. It promotes tumor cell proliferation by negatively regulating cell apoptosis and facilitating cell division. Survivin's selective expression pattern suggests that it might be a suitable target for cancer therapy, which would promote death of transformed but not normal cells. This was tested using artificial microRNAs (amiRNAs) targeting survivin. After screening, two effective amiRNAs, which knocked down survivin expression, were identified and cloned into a replication-defective adenoviral vector. Tumor cells infected with the recombinant vector downregulated expression of survivin and underwent apoptotic cell death. Further studies showed that apoptosis was associated with increases in caspase 3 and cleaved Poly (ADP-ribose) polymerase, and activation of the p53 signaling pathway. Furthermore, amiRNA treatment caused blockade of mitosis and cell cycle arrest at the G2/M phase. In vivo, survivin-targeting amiRNAs expressed by adenoviral vectors effectively delayed growth of hepatocellular and cervical carcinomas in mouse xenograft models. These results indicate that silencing of survivin by amiRNA has potential for treatment of cancer.

Combined magnetic nanoparticle-based microRNA and hyperthermia therapy to enhance apoptosis in brain cancer cells

A novel therapy is demonstrated utilizing magnetic nanoparticles for the dual purpose of delivering microRNA and inducing magnetic hyperthermia. In particular, the combination of lethal-7a microRNA (let-7a), which targets a number of the survival pathways that typically limit the effectiveness of hyperthermia, with magnetic hyperthermia greatly enhances apoptosis in brain cancer cells.

Pulmonary adenocarcinoma: implications of the recent advances in molecular biology, treatment and the IASLC/ATS/ERS classification

A decade ago, lung cancer could conveniently be classified into two broad categories-either the small cell lung carcinoma (SCLC), or the non-small cell lung carcinoma (NSCLC), mainly to assist in further treatment related decision making. However, the understanding regarding the eligibility of adenocarcinoma histology for treatments with agents such as pemetrexed and bevacizumab made it a necessity for NSCLC to be classified into more specific sub-groups. Then, the availability of molecular targeted therapy with oral tyrosine kinase inhibitors (TKIs) such as gefitinib and erlotinib not only further emphasized the need for accurate sub-classification of lung cancer, but also heralded the important role of molecular profiling of lung adenocarcinomas. Given the remarkable advances in molecular biology, oncology and radiology, a need for felt for a revised classification for lung adenocarcinoma, since the existing World Health Organization (WHO) classification of lung cancer, published in the year 2004 was mainly a pathological system of classification. Thus, there was a combined effort by the International Association for the Study of Lung Cancer (IASLC), the American Thoracic Society (ATS) and the European Respiratory Society (ERS) with an effort to inculcate newly established perspectives from clinical, molecular and radiological aspects in evolving a modern classification for lung adenocarcinomas. This review provides a summary of the recent advances in molecular biology and molecular targeted therapy with respect to lung adenocarcinoma. Also, a brief summation of the salient recommendations provided in the IASLC/ATS/ERS classification of lung adenocarcinomas is provided. Lastly, a discussion regarding the future prospects with lung adenocarcinoma is included.

Promoter methylated microRNAs: potential therapeutic targets in gastric cancer

Gastric cancer (GC) is the fourth most commonly diagnosed type of cancer worldwide and has the second highest mortality rate of all cancer types. Classical genetics alone does not fully explain how GC occurs; however, epigenetics provides a partial explanation with regard to the cause of cancer. DNA methylation, the best-known type of epigenetic marker, represses the expression of tumor-suppressor genes and is involved in the pathogenesis of various types of human cancer, including GC. Micro (mi)RNAs are critical in the initiation, progression, metastasis and invasion of GC through gene regulation. The dysregulation of miRNAs is widely recognized as a hallmark of cancer. Recently, studies concerning DNA methylation of miRNAs in GC have been frequently reported, and these studies deepen the knowledge of how epigenetic regulation of miRNAs results in GC pathogenesis and indicate novel therapeutic strategies for GC. The present review provides an overview of the reported DNA methylation of miRNAs in GC.

miR-524-5p suppresses the growth of oncogenic BRAF melanoma by targeting BRAF and ERK2

It has been well documented that miRNAs can modulate the effectiveness of cancer-associated signaling pathways. Mitogen-activated protein kinase (MAPK/ERK) signaling plays an essential role in the progression of many cancers, including melanoma and colon cancers. However, no single miRNA is reported to directly target multiple components of the MAPK/ERK pathway. We performed a miRNA PCR array screening with various MAPK/ERK signaling activities. The miRNA array data revealed that the expression of miR-524-5p was decreased in cells with an active MAPK/ERK pathway and confirmed that the expression of miR-524-5p is inversely associated with the activity of the MAPK/ERK pathway. We demonstrated that miR-524-5p directly binds to the 3'-untranslated regions of both BRAFandERK2 and suppresses the expression of these proteins. Because BRAF and ERK2 are the main components of MAPK signaling, the overexpression of miR-524-5p effectively inhibits MAPK/ERK signaling, tumor proliferation, and melanoma cell migration. Moreover, tumors overexpressing miR-524-5p were significantly smaller than those of the negative control mice. Our findings provide new insight into the role of miR-524-5p as an important miRNA that negatively regulates the MAPK/ERK signaling pathway, suggesting that miR-524-5p could be a potent therapeutic candidate for melanoma treatment.

MicroRNA-495 mimics delivery inhibits lung tumor progression

MicroRNAs (miRNAs) can function as tumor suppressors and might provide an efficient strategy for annihilating cancer. Specific miRNAs can be reintroduced into tumor cells to elicit the tumor suppressor activities. We show that systemically delivered, synthetic miRNA mimics in complex with a novel neutral lipid emulsion are preferentially targeted to lung tumors and show therapeutic benefit in mouse models of lung cancer. The delivery was demonstrated using mimics of the tumor suppressor microRNA-495 which is found downregulated in most lung cancer. Systemic treatment of a Kras-activated autochthonous mouse model of non-small cell lung cancer (NSCLC) led to a significant decrease in tumor burden. Specifically, mice treated with microRNA-495 displayed a large reduction in tumor area compared to mice treated with a miRNA control. These findings provide direct evidence that systematically delivered synthetic miRNA mimics to the mammalian lung can inhibit tumor proliferation and support the promise of miRNAs as a targeted therapy for lung cancer in future.

Role of microRNA-34 family in cancer with particular reference to cancer angiogenesis

MicroRNA-34 is involved in pathogenesis in cancer by targeting different tumor-related genes. It could be a biomarker for predicting the prognosis of patients with cancer. In addition, miR-34 is involved in the tumor angiogenesis. Understanding the mechanism of the miR-34 in cancer and tumor angiogenesis will open horizons for development of anti-cancer and anti-angiogenesis drugs.

MicroRNA-125a reduces proliferation and invasion of oral squamous cell carcinoma cells by targeting estrogen-related receptor α: implications for cancer therapeutics

Estrogen-related receptor α (ESRRA) functions as a transcription factor and regulates the expression of several genes, such as WNT11 and OPN. Up-regulation of ESRRA has been reported in several cancers. However, the mechanism underlying its up-regulation is unclear. Furthermore, the reports regarding the role and regulation of ESRRA in oral squamous cell carcinoma (OSCC) are completely lacking. Here, we show that tumor suppressor miR-125a directly binds to the 3'UTR of ESRRA and represses its expression. Overexpression of miR-125a in OSCC cells drastically reduced the level of ESRRA, decreased cell proliferation, and increased apoptosis. Conversely, the delivery of an miR-125a inhibitor to these cells drastically increased the level of ESRRA, increased cell proliferation, and decreased apoptosis. miR-125a-mediated down-regulation of ESRRA impaired anchorage-independent colony formation and invasion of OSCC cells. Reduced cell proliferation and increased apoptosis of OSCC cells were dependent on the presence of the 3'UTR in ESRRA. The delivery of an miR-125a mimic to OSCC cells resulted in marked regression of xenografts in nude mice, whereas the delivery of an miR-125a inhibitor to OSCC cells resulted in a significant increase of xenografts and abrogated the tumor suppressor function of miR-125a. We observed an inverse correlation between the expression levels of miR-125a and ESRRA in OSCC samples. In summary, up-regulation of ESRRA due to down-regulation of miR-125a is not only a novel mechanism for its up-regulation in OSCC, but decreasing the level of ESRRA by using a synthetic miR-125a mimic may have an important role in therapeutic intervention of OSCC and other cancers.

MiR-29b replacement inhibits proteasomes and disrupts aggresome+autophagosome formation to enhance the antimyeloma benefit of bortezomib

Evading apoptosis is a cancer hallmark that remains a serious obstacle in current treatment approaches. Although proteasome inhibitors (PIs) have transformed management of multiple myeloma (MM), drug resistance emerges through induction of the aggresome+autophagy pathway as a compensatory protein clearance mechanism. Genome-wide profiling identified microRNAs (miRs) differentially expressed in bortezomib-resistant myeloma cells compared with drug-naive cells. The effect of individual miRs on proteasomal degradation of short-lived fluorescent reporter proteins was then determined in live cells. MiR-29b was significantly reduced in bortezomib-resistant cells as well as in cells resistant to second-generation PIs carfilzomib and ixazomib. Luciferase reporter assays demonstrated that miR-29b targeted PSME4 that encodes the proteasome activator PA200. Synthetically engineered miR-29b replacements impaired the growth of myeloma cells, patient tumor cells and xenotransplants. MiR-29b replacements also decreased PA200 association with proteasomes, reduced the proteasome's peptidase activity and inhibited ornithine decarboxylase turnover, a proteasome substrate degraded through ubiquitin-independent mechanisms. Immunofluorescence studies revealed that miR-29b replacements enhanced the bortezomib-induced accumulation of ubiquitinated proteins but did not reveal aggresome or autophagosome formation. Taken together, our study identifies miR-29b replacements as the first-in-class miR-based PIs that also disrupt the autophagy pathway and highlight their potential to synergistically enhance the antimyeloma effect of bortezomib.

Modulation of chemotherapeutic drug resistance in neuroblastoma SK-N-AS cells by the neural apoptosis inhibitory protein and miR-520f

The acquisition of multidrug resistance is a major impediment to the successful treatment of neuroblastoma, a clinically heterogeneous cancer accounting for ∼15% of all pediatric cancer deaths. The MYCN transcription factor, whose gene is amplified in ∼30% of high-risk neuroblastoma cases, influences drug resistance by regulating a cadre of genes, including those involved with drug efflux, however, other high-risk subtypes of neuroblastoma lacking MYCN amplification, such as those with chromosome 11q deletions, also acquire multidrug resistance. To elucidate additional mechanisms involved with drug resistance in non-MYCN amplified tumour cells, an SK-N-AS subline (SK-N-AsCis24) that is significantly resistant to cisplatin and cross resistant to etoposide was developed through a pulse-selection process. High resolution aCGH analysis of SK-N-AsCis24 revealed a focal gain on chromosome 5 containing the coding sequence for the neural apoptosis inhibitory protein (NAIP). Significant overexpression of NAIP mRNA and protein was documented, while experimental modulation of NAIP levels in both SK-N-AsCis24 and in parental SK-N-AS cells confirmed that NAIP was responsible for the drug resistant phenotype by apoptosis inhibition. Furthermore, a decrease in the NAIP targeting microRNA, miR-520f, was also demonstrated to be partially responsible for increased NAIP levels in SK-N-AsCis24. Interestingly, miR-520f levels were determined to be significantly lower in postchemotherapy treatment tumours relative to matched prechemotherapy samples, consistent with a role for this miRNA in the acquisition of drug resistance in vivo, potentially through decreased NAIP targeting. Our findings provide biological novel insight into neuroblastoma drug-resistance and have implications for future therapeutic research.

MicroRNA-449 suppresses proliferation of hepatoma cell lines through blockade lipid metabolic pathway related to SIRT1

MicroRNA (miRNA or miR) inhibition of oncogenic related pathways has been shown to be a promising therapeutic approach for cancer. SIRT1 might be a promoter factor on tumorigenesis of hepatocellular carcinoma (HCC). However, the mechanism is unknown. We investigated whether miRNAs regulate the SIRT1 and its downstream SREBP-lipogenesis-cholesterogenesis metabolic pathway in hepatoma cells. Human hepatoma cells were transfected with miR-449 mimics and inhibitors, and the effects of miR-449 on cell proliferation was assessed. We identified the miRNAs, miR-449, that control lipogenesis and cholesterogenesis in hepatoma cells by inhibiting SIRT1 and SREBP-1c expression and downregulating their targeted genes, including fatty acid synthase (FASN) and 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR). MiR-449 repressed DNA synthesis, mitotic entry and proliferation of hepatoma cells. Restoration of miR-449 led to suppression of SIRT1 expression and liver tumorigenesis. The newly identified miRNAs, miR-449 represents a novel targeting mechanism for HCC therapy.

Arginine-rich, cell penetrating peptide-anti-microRNA complexes decrease glioblastoma migration potential

MicroRNAs (miRNAs) are a class of gene regulators originating from non-coding endogenous RNAs. Altered expression, both up- and down-regulation, of miRNAs plays important roles in many human diseases. Correcting miRNA dysregulation by either inhibiting or restoring miRNA function may provide therapeutic benefit. However, efficient, nontoxic miRNA delivery systems are in need. Cell penetrating peptides (CPPs) have been widely exploited for protein, DNA, and RNA delivery. Few have examined CPP transfection efficiency with single stranded anti-miRNA. The R8 peptide condensed both siRNA and anti-miRNA. Greater than 50% of cells had anti-miRNA/R8 complexes associated and in these cells 68% of anti-miRNA escapes the endosome/lysosome. Single-stranded antisense miR-21 inhibitor (anti-miR-21) administered using the R8 peptide elicited efficient downstream gene upregulation. Glioblastoma cell migration was inhibited by 25% compared to the negative control group. To our knowledge, this is the first demonstration of miRNA modulation with anti-miR-21/R8 complexes, which has laid the groundwork for further exploring octaarginine as intracellular anti-miRNAs carrier.

Systemic delivery of a miR34a mimic as a potential therapeutic for liver cancer

miR34a is a tumor-suppressor miRNA that functions within the p53 pathway to regulate cell-cycle progression and apoptosis. With apparent roles in metastasis and cancer stem cell development, miR34a provides an interesting opportunity for therapeutic development. A mimic of miR34a was complexed with an amphoteric liposomal formulation and tested in two different orthotopic models of liver cancer. Systemic dosing of the formulated miR34a mimic increased the levels of miR34a in tumors by approximately 1,000-fold and caused statistically significant decreases in the mRNA levels of several miR34a targets. The administration of the formulated miR34a mimic caused significant tumor growth inhibition in both models of liver cancer, and tumor regression was observed in more than one third of the animals. The antitumor activity was observed in the absence of any immunostimulatory effects or dose-limiting toxicities. Accumulation of the formulated miR34a mimic was also noted in the spleen, lung, and kidney, suggesting the potential for therapeutic use in other cancers.

MicroRNAs as novel biological targets for detection and regulation

MicroRNAs are being considered as a novel type of bio-markers and potential therapeutic targets for various diseases. Diverse chemical tools are being developed for the detection or regulation of microRNAs with bio-medical implications. Chemical probes have been developed for use in combination with in situ signal amplification strategies to realize sensitive detection of microRNAs of low abundance. Regulation of microRNAs aberrantly expressed in tumours represents a new approach to cancer chemotherapy. Synthetic oligonucleotides including antisense oligonucleotides and microRNA mimics have been successfully delivered into cells or tissues to inhibit or enhance the function of specific endogenous microRNAs. Small-molecule modifiers of microRNAs that modify the expression or function of endogenous microRNAs are emerging not only as useful probes to explore microRNA-involved regulatory networks, but also as potential therapeutic reagents. In this tutorial review, we discuss the strategies developed by chemists in recent years for microRNA detection and regulation, with a focus on the potential of these chemical tools in microRNA-related biomedical applications.

MicroRNA-377 inhibited proliferation and invasion of human glioblastoma cells by directly targeting specificity protein 1

BACKGROUND

Increasing evidence has indicated that microRNAs (miRNAs) are strongly implicated in the initiation and progression of glioblastoma multiforme (GBM). Here, we identified a novel tumor suppressive miRNA, miR-377, and investigated its role and therapeutic effect for GBM.

METHODS

MiRNA global screening was performed on GBM patient samples and adjacent nontumor brain tissues. The expression of miR-377 was detected by real-time reverse-transcription PCR. The effects of miR-377 on GBM cell proliferation, cell cycle progression, invasion, and orthotopic tumorigenicity were investigated The therapeutic effect of miR-377 mimic was explored in a subcutaneous GBM model. Western blot and luciferase reporter assay were used to identify the direct and functional target of miR-377.

RESULTS

MiR-377 was markedly downregulated in human GBM tissues and cell lines. Overexpression of miR-377 dramatically inhibited cell growth both in culture and in orthotopic xenograft tumor models, blocked G1/S transition, and suppressed cell invasion in GBM cells. Importantly, introduction of miR-377 could strongly inhibit tumor growth in a subcutaneous GBM model. Subsequent investigation revealed that specificity protein 1 (Sp1) was a direct and functional target of miR-377 in GBM cells. Silencing of Sp1 recapitulated the antiproliferative and anti-invasive effects of miR-377, whereas restoring the Sp1 expression antagonized the tumor-suppressive function of miR-377. Finally, analysis of miR-377 and Sp1 levels in human GBM tissues revealed that miR-377 is inversely correlated with Sp1 expression.

CONCLUSION

These findings reveal that miR-377/Sp1 signaling that may be required for GBM development and may consequently serve as a therapeutic target for the treatment of GBM.

The potential clinical applications and prospects of microRNAs in lung cancer

Lung cancer is the major cause of cancer deaths worldwide due to its late diagnosis and poor outcome. Understanding genomic medicine may widen our vision into the oncogenesis of lung cancer and may open the door to improvements in the clinical management of lung cancer. It is well known that almost half of all genes are regulated by microRNAs (miRNAs). This review focuses on the role of miRNAs in lung cancer and also touches on the value of miRNA-based novel therapies for lung cancers.

miRNAs in PAH: biomarker, therapeutic target or both?

Pulmonary arterial hypertension (PAH) is characterized by progressive increase in pulmonary vascular resistance leading to right ventricular hypertrophy and failure. There is a need to find new biomarkers to detect PAH at its early stages and also for new, more effective treatments for this disease. miRNAs have emerged as key players in cardiovascular diseases and cancer development and progression and, more recently, in PAH pathogenesis. In this review, we focus on the potential of miRNAs as biomarkers and new therapeutic targets for PAH.

MicroRNAs: short non-coding players in cancer chemoresistance

Chemoresistance is one of the main problems in the therapy of cancer. There are a number of different molecular mechanisms through which a cancer cell acquires resistance to a specific treatment, such as alterations in drug uptake, drug metabolism and drug targets. There are several lines of evidence showing that miRNAs are involved in drug sensitivity of cancer cells in different tumor types and by different treatments. In this review, we provide an overview of the more recent and significant findings on the role of miRNAs in cancer cell drug resistance. In particular, we focus on specific miRNA mechanisms of action that in various steps lead from drug cell sensitivity to drug cell resistance. We also provide evidence on how miRNA profiling may unveil relevant predictive biomarkers for therapy outcomes.

MicroRNAs: short non-coding players in cancer chemoresistance

Chemoresistance is one of the main problems in the therapy of cancer. There are a number of different molecular mechanisms through which a cancer cell acquires resistance to a specific treatment, such as alterations in drug uptake, drug metabolism and drug targets. There are several lines of evidence showing that miRNAs are involved in drug sensitivity of cancer cells in different tumor types and by different treatments. In this review, we provide an overview of the more recent and significant findings on the role of miRNAs in cancer cell drug resistance. In particular, we focus on specific miRNA mechanisms of action that in various steps lead from drug cell sensitivity to drug cell resistance. We also provide evidence on how miRNA profiling may unveil relevant predictive biomarkers for therapy outcomes.

miRNA microarray reveals specific expression in the peripheral blood of glioblastoma patients

MicroRNAs (miRNAs) are frequently dysregulated in glioblastoma (GBM) patients. It has been discovered that highly stable extracellular miRNAs circulate in the blood of both healthy individuals and patients. miRNAs in serum of patients with GBM and normal controls were analyzed by microarray analysis. The relevant bioinformatic analysis of the predicted target genes (gene ontology, pathway, gene network analysis) were performed. The miRNA microarray reveals differentially expressed miRNAs in serum between the GBM and normal controls. Of the 752 miRNAs, 115 miRNAs were upregulated in the GBM group, and 24 miRNAs were downregulated (fold change ≥2.0, P<0.01). By further analysis, we found that miR-576-5p, miR-340 and miR-626 were significantly overexpressed, but miR-320, let-7g-5p and miR-7-5P showed significantly low expression in GBM patients. By further bioinformatic analysis, we found that they possibly play important roles in the regulation of glioma signaling pathways. In summary, the six miRNAs are significant distinct in the peripheral blood of patients with GBM pathologies. These data suggest that the miRNA profile of the peripheral blood may serve as a new biomarker for glioma diagnosis with high specificity and sensitivity.

The role of micro-RNAs in hepatocellular carcinoma: from molecular biology to treatment

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the third leading cause of cancer deaths. microRNAs (miRNAs) are evolutionary conserved small non-coding RNA that negatively regulate gene expression and protein translation. Recent evidences have shown that they are involved in many biological processes, from development and cell-cycle regulation to apoptosis. miRNAs can behave as tumor suppressor or promoter of oncogenesis depending on the cellular function of their targets. Moreover, they are frequently dysregulated in HCC. In this review we summarize the latest findings of miRNAs regulation in HCC and their role as potentially diagnostic and prognostic biomarkers for HCC. We highlight development of miRNAs as potential therapeutic targets for HCC.

Role of microRNA-1 in human cancer and its therapeutic potentials

While the mechanisms of human cancer development are not fully understood, evidence of microRNA (miRNA, miR) dysregulation has been reported in many human diseases, including cancer. miRs are small noncoding RNA molecules that regulate posttranscriptional gene expression by binding to complementary sequences in the specific region of gene mRNAs, resulting in downregulation of gene expression. Not only are certain miRs consistently dysregulated across many cancers, but they also play critical roles in many aspects of cell growth, proliferation, metastasis, apoptosis, and drug resistance. Recent studies from our group and others revealed that miR-1 is frequently downregulated in various types of cancer. Through targeting multiple oncogenes and oncogenic pathways, miR-1 has been demonstrated to be a tumor suppressor gene that represses cancer cell proliferation and metastasis and promotes apoptosis by ectopic expression. In this review, we highlight recent findings on the aberrant expression and functional significance of miR-1 in human cancers and emphasize its significant values for therapeutic potentials.

Significance and therapeutic value of miRNAs in embryonal neural tumors

Embryonal tumors of the nervous system are the leading cause of childhood cancer-related morbidity and mortality. Medulloblastoma, supratentorial primitive neuroectodermal tumors, atypical teratoid/rhabdoid tumor and neuroblastoma account for more than 20% of childhood malignancies and typify the current neural embryonal tumor model in pediatric oncology. Mechanisms driving the formation of these tumors point towards impaired differentiation of neuronal and neuron-associated cells during the development of the nervous system as an important factor. The importance of microRNAs (miRNAs) for proper embryonic cell function has been confirmed and their aberrant expressions have been linked to tumor development. The role of miRNAs in controlling essential regulators of key pathways implicated in tumor development makes their use in diagnostics a powerful tool to be used for early detection of cancer, risk assessment and prognosis, as well as for the design of innovative therapeutic strategies. In this review we focus on the significance of miRNAs involved in the biology of embryonal neural tumors, delineate their clinical significance and discuss their potential as a novel therapeutic target.

Tumor aerobic glycolysis: new insights into therapeutic strategies with targeted delivery

INTRODUCTION

Cancer cells acclimatize to the harsh tumor microenvironment by altering cellular metabolism in favor of aerobic glycolysis. This process provides a source of energy and also generates essential components for macromolecular biosynthesis, which enables cellular survival. As the dependence of cancer cells on glycolysis affects tumorigenesis, it has become an attractive target for therapeutic intervention. Several preclinical studies have shown the effectiveness of using biological targets from the glycolytic pathway for anticancer therapy.

AREAS COVERED

This review provides an insight into the glycolytic pathway, highlighting potential targets for glycolytic inhibition. We then discuss recent advancement in delivery strategies that have the potential to circumvent some of the problems posed by current glycolytic inhibitors, enabling resurrection of abandoned therapeutic agents.

EXPERT OPINION

Targeting the glycolysis pathway is a tactical approach for cancer therapy. However, the current nonspecific therapeutic strategies have several drawbacks such as poor bioavailability, unfavorable pharmacokinetic profile and associated nonspecific toxicity, thereby limiting preclinical investigation. In recent years, nanoparticle systems have received recognition for the delivery of therapeutic agents directly to the tumor tissue. Thus, it is envisaged that this strategy can be expanded for the delivery of current glycolytic inhibitors specifically to tumor tissues providing improved anticancer activity.

Exploitation of a very small peptide nucleic acid as a new inhibitor of miR-509-3p involved in the regulation of cystic fibrosis disease-gene expression

Computational techniques, and in particular molecular dynamics (MD) simulations, have been successfully used as a complementary technique to predict and analyse the structural behaviour of nucleic acids, including peptide nucleic acid- (PNA-) RNA hybrids. This study shows that a 7-base long PNA complementary to the seed region of miR-509-3p, one of the miRNAs involved in the posttranscriptional regulation of the CFTR disease-gene of Cystic Fibrosis, and bearing suitable functionalization at its N- and C-ends aimed at improving its resistance to nucleases and cellular uptake, is able to revert the expression of the luciferase gene containing the 3′UTR of the gene in A549 human lung cancer cells, in agreement with the MD results that pointed at the formation of a stable RNA/PNA heteroduplex notwithstanding the short sequence of the latter. The here reported results widen the interest towards the use of small PNAs as effective anti-miRNA agents.

Tumor suppressor function of miR-483-3p on squamous cell carcinomas due to its pro-apoptotic properties

The frequent alteration of miRNA expression in many cancers, together with our recent reports showing a robust accumulation of miR-483-3p at the final stage of skin wound healing, and targeting of CDC25A leading to an arrest of keratinocyte proliferation, led us to hypothesize that miR-483-3p could also be endowed with antitumoral properties. We tested that hypothesis by documenting the in vitro and in vivo impacts of miR-483-3p in squamous cell carcinoma (SCC) cells. miR-483-3p sensitized SCC cells to serum deprivation- and drug-induced apoptosis, thus exerting potent tumor suppressor activities. Its pro-apoptotic activity was mediated by a direct targeting of several anti-apoptotic genes, such as API5, BIRC5, and RAN. Interestingly, an in vivo delivery of miR-483-3p into subcutaneous SCC xenografts significantly hampered tumor growth. This effect was explained by an inhibition of cell proliferation and an increase of apoptosis. This argues for its further use as an adjuvant in the many instances of cancers characterized by a downregulation of miR-483-3p.

Roles of miR-375 in digestive tumors

MicroRNAs (miRNAs) are a group of small non-coding RNAs that regulate gene expression post-transcriptionally. A large body of evidence has indicated that dysregulation of miRNAs is an important hallmark of cancer. MiRNAs modulate malignant phenotypes of cancer by repressing many critical oncogenes or tumor suppressors. MiR-375 was firstly identified in pancreatic beta-cells and it can regulate insulin secretion and pancreatic development. Further studies found that miR-375 is significantly downregulated in multiple types of tumors, especially digestive system tumors, such as hepatocellular carcinoma, gastric cancer, esophageal cancer, and pancreatic cancer. Overexpression of miR-375 represses target genes, such as AEG-1, JAK2, ATG7, IGF1R, PDK1, 14-3-3Z and YAP1, and thereby inhibits malignant properties of cancer. It is also found that miR-375 in tissues or circulation could be used as a biomarker for diagnosis or prognosis prediction in digestive system tumors. Since miR-375 play an important role in the initiation and progression of digestive system tumors, it can become a novel therapeutic target. Monitoring the levels of miR-375 may contribute to the early diagnosis and prognosis prediction.