Blockage of miR-92a-3p with locked nucleic acid induces apoptosis and prevents cell proliferation in human acute megakaryoblastic leukemia

Effect of mir-92a-3p on hydroquinone induced changes in human lymphoblastoid cell cycle and apoptosis

Hydroquinone (HQ), one of the metabolites of benzene in humans, has significant hepatotoxic properties. Chronic exposure to HQ can lead to leukemia. In a previous study by this group, we constructed a model of malignant transformation of human lymphoblastoid cells (TK6) induced by chronic exposure to HQ with significant subcutaneous tumorigenic capacity in nude mice. miR-92a-3p is a tumor factor whose role in HQ-induced malignant transformation is not yet clear. In the present study, raw signal analysis and dual-luciferase reporter gene results suggested that miR-92a-3p could target and regulate TOB1, and the expression level of miR-92a-3p was significantly upregulated in the long-term HQ-induced TK6 malignant transformation model, while the anti-proliferative factor TOB1 was significantly downregulated. To investigate the mechanism behind this, we inhibited miR-92a-3p in a malignant transformation model and found a decrease in cell viability, a decrease in MMP-9 protein levels, a G2/M phase block in the cell cycle, and an upregulation of the expression of G2/M phase-related proteins cyclinB1 and CDK1. Inhibition of miR-92a-3p in combination with si-TOB1 restored cell viability, inhibited cyclin B1 and CDK1 protein levels, and attenuated the G2/M phase block. Taken together, miR-92a-3p reduced the cell proliferation rate of HQ19 and caused cell cycle arrest by targeting TOB1, which in turn contributed to the altered malignant phenotype of the cells. This study suggests that miR-92a-3p is likely to be a biomarker for long-term HQ-induced malignant transformation of TK6 and could be a potential therapeutic target for leukemia caused by long-term exposure to HQ.

DNA methylation and miR-92a-3p-mediated repression of HIP1R promotes pancreatic cancer progression by activating the PI3K/AKT pathway

Pancreatic cancer (PAAD) is a highly malignant tumour characterized of high mortality and poor prognosis. Huntingtin-interacting protein 1-related (HIP1R) has been recognized as a tumour suppressor in gastric cancer, while its biological function in PAAD remains to be elucidated. In this study, we reported the downregulation of HIP1R in PAAD tissues and cell lines, and the overexpression of HIP1R suppressed the proliferation, migration and invasion of PAAD cells, while silencing HIP1R showed the opposite effects. DNA methylation analysis revealed that the promoter region of HIP1R was heavily methylated in PAAD cell lines when compared to the normal pancreatic duct epithelial cells. A DNA methylation inhibitor 5-AZA increased the expression of HIP1R in PAAD cells. 5-AZA treatment also inhibited the proliferation, migration and invasion, and induced apoptosis in PAAD cell lines, which could be attenuated by HIP1R silencing. We further demonstrated that HIP1R was negatively regulated by miR-92a-3p, which modulates the malignant phenotype of PAAD cells in vitro and the tumorigenesis in vivo. The miR-92a-3p/HIP1R axis could regulate PI3K/AKT pathway in PAAD cells. Taken together, our data suggest that targeting DNA methylation and miR-92a-3p-mediated repression of HIP1R could serve as novel therapeutic strategies for PAAD treatment.

Vorinostat triggers miR-769-5p/3p-mediated suppression of proliferation and induces apoptosis via the STAT3-IGF1R-HDAC3 complex in human gastric cancer

Previous reports have shown that histone deacetylase inhibitors (HDACi) can alter miRNA expression in a range of cancers. Both the 5p-arm and 3p-arm of mature miRNAs can be expressed from the same precursor and involved in cancer progress. Nevertheless, the detailed mechanism by which vorinostat (SAHA), a HDACi, triggers miR-769-5p/miR-769-3p-mediated suppression of proliferation and induces apoptosis in gastric cancer (GC) cells remains elusive. Here, we showed that the miRNA-seq analysis of GC cells treated with SAHA identified seven differentially expressed miRNAs with both strands of the miRNA duplex. miR-769-5p/miR-769-3p expression was downregulated in GC tissues compared with normal tissues. Functionally, high expression of miR-769-5p/miR-769-3p blocked the malignant abilities of GC cells. Mechanistically, miR-769-5p/miR-769-3p targeted IGF1R and IGF1R overexpression rescued the effects of miR-769-5p/miR-769-3p on GC cells growth and metastasis. Moreover, STAT3 bound to the promoter of miR-769. Furthermore, miR-769-5p/miR-769-3p expression was negatively regulated by the STAT3-IGF1R-HDAC3 complex. Besides, miR-769-5p/miR-769-3p synergized with SAHA to promote GC cells apoptosis. Our studies suggest that miR-769-5p/miR-769-3p acts as a tumor suppressor by the STAT3-IGF1R-HDAC3 complex. Moreover, SAHA triggers miR-769-5p/miR-769-3p-mediated inhibition of proliferation and induces apoptosis in GC cells.

microRNAs Mediated Regulation of the Ribosomal Proteins and its Consequences on the Global Translation of Proteins

Ribosomal proteins (RPs) are mostly derived from the energy-consuming enzyme families such as ATP-dependent RNA helicases, AAA-ATPases, GTPases and kinases, and are important structural components of the ribosome, which is a supramolecular ribonucleoprotein complex, composed of Ribosomal RNA (rRNA) and RPs, coordinates the translation and synthesis of proteins with the help of transfer RNA (tRNA) and other factors. Not all RPs are indispensable; in other words, the ribosome could be functional and could continue the translation of proteins instead of lacking in some of the RPs. However, the lack of many RPs could result in severe defects in the biogenesis of ribosomes, which could directly influence the overall translation processes and global expression of the proteins leading to the emergence of different diseases including cancer. While microRNAs (miRNAs) are small non-coding RNAs and one of the potent regulators of the post-transcriptional gene expression, miRNAs regulate gene expression by targeting the 3' untranslated region and/or coding region of the messenger RNAs (mRNAs), and by interacting with the 5' untranslated region, and eventually finetune the expression of approximately one-third of all mammalian genes. Herein, we highlighted the significance of miRNAs mediated regulation of RPs coding mRNAs in the global protein translation.

MicroRNA-204-5p regulates apoptosis by targeting Bcl2 in rat ovarian granulosa cells exposed to cadmium†

This study aimed to investigate whether cadmium (Cd) cytotoxicity in rat ovarian granulosa cells (OGCs) is mediated through apoptosis or autophagy and to determine the role of microRNAs (miRNAs) in Cd cytotoxicity. To test this hypothesis, rat OGCs were exposed to 0, 10, and 20 μM CdCl2 in vitro. As the Cd concentration increased, OGC apoptosis increased. In addition, Cd promoted apoptosis by decreasing the mRNA and protein expression levels of inhibition of B-cell lymphoma 2 (Bcl2). However, under our experimental conditions, no autophagic changes in rat OGCs were observed, and the mRNA and protein expression levels of the autophagic markers microtubule-associated protein 1 light chain 3 alpha (Map1lc3b) and Beclin1 (Becn1) were not changed. Microarray chip analysis, miRNA screening, and bioinformatics approaches were used to further explore the roles of apoptosis regulation-related miRNAs. In total, 19 miRNAs putatively related to Cd-induced apoptosis in rat OGCs were identified. Notably, miR-204-5p, which may target Bcl2, was identified. Then, rat OGCs were cultured in vitro and used to construct the miR-204-5p-knockdown cell line LV2-short hairpin RNA (shRNA). LV2-shRNA cells were exposed to 20 μM Cd for 12 h, and the mRNA and protein expression levels of Bcl2 were increased. Our findings suggest that Cd is cytotoxic to rat OGCs, and mitochondrial apoptosis rather than autophagy mediates Cd-induced damage to OGCs. Cd also affects apoptosis-related miRNAs, and the underlying apoptotic mechanism may involve the Bcl2 gene.

An Antisense Oligonucleotide Drug Targeting miR-21 Induces H1650 Apoptosis and Caspase Activation

Non-small cell lung cancer is the most common malignant tumor in the world. Currently, chemotherapy is still the major method for non-small cell lung cancer treatment, but the problem of cancer drug resistance still exists, so we designed 5 different phosphorothioate oligonucleotides to silence key genes in tumor cell development, which could help avoid inducing cancer cell drug resistance. MicroRNAs have been shown to play a crucial role in the pathogenesis and progression of many malignancies, such as breast, colon, lung, and pancreatic cancer. According to the data from the Gene Expression Omnibus database, miR-21 has been reported to be one of the top 20 differentially expressed microRNAs screened using the Morpheus online tool, and miR-21 has been revealed to regulate a series of biological behaviors in cancer cells, including cell proliferation, migration, invasion, metastasis, and apoptosis. In recent years, gene therapy has emerged as a new therapeutic strategy for cancer treatment. Antisense oligonucleotides have recently been suggested as a novel approach for targeting microRNAs by antisense-based gene silencing. Five phosphorothioate oligonucleotides were designed, synthesized, and screened for anticancer activity. Reverse transcription-polymerase chain reaction was used to detect the relative expression of miR21. Among these 5 sequences, only phosphorothioate oligonucleotide 4 inhibited the proliferation of H1650 cells, and this effect was due to the induction of cancer cell apoptosis by activating the caspase-8 apoptotic pathway. In conclusion, this research confirmed the anticancer activity of phosphorothioate oligonucleotide 4 and revealed the underlying mechanism, which has the potential to be a novel anticancer strategy.

Cell proliferation is induced in renal cell carcinoma through miR-92a-3p upregulation by targeting FBXW7

Renal cell carcinoma (RCC) is the most common type of kidney cancer whose incidence has gradually increased worldwide. MicroRNAs (miRNAs) represent a type of short endogenous non-coding RNA containing approximately 22 nucleotides, which are capable of regulating mRNAs at the post-transcriptional level in human cells. miRNAs have been demonstrated to mediate gene expression by influencing important regulatory genes. Accumulating evidence indicates that certain miRNAs are involved in RCC development. The present study investigated the underlying mechanism and functional role of miR-92a-3p in RCC cells using reverse transcription-quantitative polymerase chain reaction, western blotting, 3′ UTR luciferase assay, cell proliferation assay and soft agar assay. The results demonstrated that miR-92a-3p expression level is significantly upregulated in RCC tissues and cell lines; however, F-box and WD repeat domain containing 7 (FBXW7) expression level was significantly downregulated in RCC tissues and cell lines. Subsequently, whether FBXW7 could be considered as a direct target of miR-92a-3p in RCC cells was investigated. The results demonstrated that miR-92a-3p overexpression significantly promoted RCC cell proliferation and colony formation. Conversely, miR-92a-3p downregulation significantly inhibited RCC cell proliferation and colony formation. In addition, FBXW7 knockdown significantly enhanced RCC cell proliferation and colony formation. Conversely, FBXW7 overexpression significantly inhibited RCC cell proliferation and colony formation. Collectively, these results demonstrated that miR-92a-3p/FBXW7 pathway may represent a novel strategy and therapeutic target for RCC.

Retraction Note: Blockage of miR-92a-3p with locked nucleic acid induces apoptosis and prevents cell proliferation in human acute megakaryoblastic leukemia

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

DeepMiR2GO: Inferring Functions of Human MicroRNAs Using a Deep Multi-Label Classification Model

MicroRNAs (miRNAs) are a highly abundant collection of functional non-coding RNAs involved in cellular regulation and various complex human diseases. Although a large number of miRNAs have been identified, most of their physiological functions remain unknown. Computational methods play a vital role in exploring the potential functions of miRNAs. Here, we present DeepMiR2GO, a tool for integrating miRNAs, proteins and diseases, to predict the gene ontology (GO) functions based on multiple deep neuro-symbolic models. DeepMiR2GO starts by integrating the miRNA co-expression network, protein-protein interaction (PPI) network, disease phenotype similarity network, and interactions or associations among them into a global heterogeneous network. Then, it employs an efficient graph embedding strategy to learn potential network representations of the global heterogeneous network as the topological features. Finally, a deep multi-label classification network based on multiple neuro-symbolic models is built and used to annotate the GO terms of miRNAs. The predicted results demonstrate that DeepMiR2GO performs significantly better than other state-of-the-art approaches in terms of precision, recall, and maximum F-measure.

MicroRNAs in cancer cell death pathways: Apoptosis and necroptosis

To protect tissues and the organism from disease, potentially harmful cells are removed through programmed cell death processes, including apoptosis and necroptosis. These types of cell death are critically controlled by microRNAs (miRNAs). MiRNAs are short RNA molecules that target and inhibit expression of many cellular regulators, including those controlling programmed cell death via the intrinsic (Bcl-2 and Mcl-1), extrinsic (TRAIL and Fas), p53-and endoplasmic reticulum (ER) stress-induced apoptotic pathways, as well as the necroptosis cell death pathway. In this review, we discuss the current knowledge of apoptosis and necroptosis pathways and how these are impaired in cancer cells. We focus on how miRNAs disrupt apoptosis and necroptosis, thereby critically contributing to malignancy. Understanding which and how miRNAs and their targets affect cell death pathways could open up novel therapeutic opportunities for cancer patients. Indeed, restoration of pro-apoptotic tumor suppressor miRNAs (apoptomiRs) or inhibition of oncogenic miRNAs (oncomiRs) represent strategies that are currently being trialed or are already applied as miRNA-based cancer therapies. Therefore, better understanding the cancer type-specific expression of apoptomiRs and oncomiRs and their underlying mechanisms in cell death pathways will not only advance our knowledge, but also continue to provide new opportunities to treat cancer.

HDAC2-dependent miRNA signature in acute myeloid leukemia

Acute myeloid leukemia (AML) arises from a complex sequence of biological and finely orchestrated events that are still poorly understood. Increasingly, epigenetic studies are providing exciting findings that may be exploited in promising and personalized cutting‐edge therapies. A more appropriate and broader screening of possible players in cancer could identify a master molecular mechanism in AML. Here, we build on our previously published study by evaluating a histone deacetylase (HDAC)2‐mediated miRNA regulatory network in U937 leukemic cells. Following a comparative miRNA profiling analysis in genetically and enzymatically HDAC2‐downregulated AML cells, we identified miR‐96‐5p and miR‐92a‐3p as potential regulators in AML etiopathology by targeting defined genes. Our findings support the potentially beneficial role of alternative physiopathological interventions.

Molecular features, prognosis, and novel treatment options for pediatric acute megakaryoblastic leukemia

INTRODUCTION

Acute megakaryoblastic leukemia (AMegL) is a rare hematological neoplasm most often diagnosed in children and is commonly associated with Down's syndrome (DS). Although AMegLs are specifically characterized and typically diagnosed by megakaryoblastic expansion, recent advancements in molecular analysis have highlighted the heterogeneity of this disease, with specific cytogenic and genetic alterations characterizing different disease subtypes. Areas covered: This review will focus on describing recurrent molecular variations in both DS and non-DS pediatric AMegL, their role in promoting leukemogenesis, their association with different clinical aspects and prognosis, and finally, their influence on future treatment strategies with a number of specific drugs beyond conventional chemotherapy already under development. Expert opinion: Deep understanding of the genetic and molecular landscape of AMegL will lead to better and more precise disease classification in terms of diagnosis, prognosis, and possible targeted therapies. Development of new therapeutic approaches based on these molecular characteristics will hopefully improve AMegL patient outcomes.

Exome, transcriptome and miRNA analysis don't reveal any molecular markers of TKI efficacy in primary CML patients

BACKGROUND

Approximately 5-20% of chronic myeloid leukemia (CML) patients demonstrate primary resistance or intolerance to imatinib. None of the existing predictive scores gives a good prognosis of TKI efficacy. Gene polymorphisms, expression and microRNAs are known to be involved in the pathogenesis of TKI resistance in CML. The aim of our study is to find new molecular markers of TKI therapy efficacy in CML patients.

METHODS

Newly diagnosed patients with Ph+ CML in chronic phase were included in this study. Optimal and non-optimal responses to TKI were estimated according to ELN 2013 recommendation. We performed genotyping of selected polymorphisms in 62 blood samples of CML patients, expression profiling of 33 RNA samples extracted from blood and miRNA profiling of 800 miRNA in 12 blood samples of CML patients.

RESULTS

The frequencies of genotypes at the studied loci did not differ between groups of patients with an optimal and non-optimal response to TKI therapy. Analysis of the expression of 34,681 genes revealed 26 differently expressed genes (p < 0.05) in groups of patients with different TKI responses, but differences were very small and were not confirmed by qPCR. Finally, we did not find difference in miRNA expression between the groups.

CONCLUSIONS

Using modern high-throughput methods such as whole-exome sequencing, transcriptome and miRNA analysis, we could not find reliable molecular markers for early prediction of TKI efficiency in Ph+ CML patients.

Oncogenic and Tumor-Suppressive Roles of MicroRNAs with Special Reference to Apoptosis: Molecular Mechanisms and Therapeutic Potential

MicroRNAs (miRNAs) are the non-coding class of minute RNA molecules that negatively control post-transcriptional regulation of various functional genes. These miRNAs are transcribed from the loci present in the introns of functional or protein-coding genes, exons of non-coding genes, or even in the 3'-untranslated region (3'-UTR). They have potential to modulate the stability or translational efficiency of a variety of target RNA [messenger RNA (mRNA)]. The regulatory function of miRNAs has been elucidated in several pathological conditions, including neurological (Alzheimer's disease and Parkinson's disease) and cardiovascular conditions, along with cancer. Importantly, miRNA identification in cancer progression and invasion has evolved as an incipient era in cancer treatment. Several studies have shown the influence of miRNAs on various cancer processes, including apoptosis, invasion, metastasis and angiogenesis. In particular, apoptosis induction in tumor cells through miRNA has been extensively studied. The biphasic mode (up- and down-regulation) of miRNA expression in apoptosis and other cancer processes has already been determined. The findings of these studies could be utilized to develop potential therapeutic strategies for the management of various cancers. The present review critically describes the oncogenic and tumor suppressor role of miRNAs in apoptosis and other cancer processes, therapy resistance, and use of their presence in the body fluids as biomarkers.

MicroRNA-613 promotes colon cancer cell proliferation, invasion and migration by targeting ATOH1

The aim of the present study is to investigate the expression and function of miR-613 in colon cancer (CC) and illuminate the molecular mechanisms underlying miR-613-regulated CC progression. Our data demonstrated that miR-613 was upregulated in CC tissue samples (P = 0.009) and human CC cell lines (HCT-116 and Lovo; P = 0.001 and P = 0.003, respectively), which also promoted the proliferation, invasion and migration of CC cells (P < 0.05). The dual-luciferase reporter assay confirmed that Atonal homolog1 (ATOH1) was the target mRNA of miR-613. Rescue experiments showed that ATOH1 overexpression vector significantly reversed the stimulative effects of miR-613 mimic on the progression of HCT-116 and Lovo cells (P < 0.001). Positive ATOH1 expression in CC tissues was significantly associated with lower grade (χ² = 3.592, P = 0.043), lower TNM stage (χ² = 3.537, P = 0.048) and better overall survival (P=0.041). Jun N-terminal kinase 1 (JNK1) pathway and Mucin 2 (MUC2) were the potential downstream proteins of miR-613/ATOH1. miR-613 is an oncogene in CC and promotes the proliferation, invasion and migration of CC cells by targeting ATOH1 likely via activating JNK1 pathway and upregulating MUC2.

OncomiR or antioncomiR: Role of miRNAs in Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) is a hematopoietic progenitor/stem cell disorder in which neoplastic myeloblasts are stopped at an immature stage of differentiation and lost the normal ability of proliferation and apoptosis. MicroRNAs (miRNAs) are small noncoding, single-stranded RNA molecules that can mediate the expression of target genes. While miRNAs mean to contribute the developments of normal functions, abnormal expression of miRNAs and regulations on their corresponding targets have often been found in the developments of AML and described in recent years. In leukemia, miRNAs may function as regulatory molecules, acting as oncogenes or tumor suppressors. Overexpression of miRNAs can down-regulate tumor suppressors or other genes involved in cell differentiation, thereby contributing to AML formation. Similarly, miRNAs can down-regulate different proteins with oncogenic activity as tumor suppressors. We herein review the current data on miRNAs, specifically their targets and their biological function based on apoptosis in the development of AML.

Knockdown of Long Noncoding RNA Plasmacytoma Variant Translocation 1 with Antisense Locked Nucleic Acid GapmeRs Exerts Tumor-Suppressive Functions in Human Acute Erythroleukemia Cells Through Downregulation of C-MYC Expression

Objective: Acute erythroleukemia (AEL) is a subtype of acute myeloid leukemia (AML), with no specific treatment. Up- or downregulation of long noncoding RNAs (lncRNAs) is strongly associated with the formation and progression of many malignancies. Plasmacytoma variant translocation 1 (PVT1) is a significantly upregulated lncRNA in AML. Antisense locked nucleic acid (LNA) GapmeRs oligonucleotides are the novel tools for targeting lncRNAs. The purpose of the current study was to investigate the functional role of PVT1 antisense LNA GapmeRs on AEL cell line (KG-1). Materials and Methods: AEL cells were transfected with PVT1 antisense LNA GapmeRs at three different time points. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was accomplished to evaluate the PVT1 expression by PVT1 antisense LNA GapmeRs. The viability was evaluated by MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide) assay, and the apoptosis and necrosis were assessed by Annexin V/propidium iodide staining assay. The C-MYC expression level, the target gene of PVT1, was also quantified by qRT-PCR. Results: The results indicated that PVT1 inhibition could significantly decrease the viability of AEL cells, due to induction of apoptosis and necrosis, probably through the downregulation of C-MYC. Conclusions: Their findings suggest that the inhibition of lncRNA PVT1 could serve as a novel approach for controlling the proliferation of AEL cells and could open up a path for treatment of AEL.

Potential biomarkers and therapeutic targets in cervical cancer: Insights from the meta-analysis of transcriptomics data within network biomedicine perspective

The malignant neoplasm of the cervix, cervical cancer, has effects on the reproductive tract. Although infection with oncogenic human papillomavirus is essential for cervical cancer development, it alone is insufficient to explain the development of cervical cancer. Therefore, other risk factors such as host genetic factors should be identified, and their importance in cervical cancer induction should be determined. Although gene expression profiling studies in the last decade have made significant molecular findings about cervical cancer, adequate screening and effective treatment strategies have yet to be achieved. In the current study, meta-analysis was performed on cervical cancer-associated transcriptome data and reporter biomolecules were identified at RNA (mRNA, miRNA), protein (receptor, transcription factor, etc.), and metabolite levels by the integration of gene expression profiles with genome-scale biomolecular networks. This approach revealed already-known biomarkers, tumor suppressors and oncogenes in cervical cancer as well as various receptors (e.g. ephrin receptors EPHA4, EPHA5, and EPHB2; endothelin receptors EDNRA and EDNRB; nuclear receptors NCOA3, NR2C1, and NR2C2), miRNAs (e.g., miR-192-5p, miR-193b-3p, and miR-215-5p), transcription factors (particularly E2F4, ETS1, and CUTL1), other proteins (e.g., KAT2B, PARP1, CDK1, GSK3B, WNK1, and CRYAB), and metabolites (particularly, arachidonic acids) as novel biomarker candidates and potential therapeutic targets. The differential expression profiles of all reporter biomolecules were cross-validated in independent RNA-Seq and miRNA-Seq datasets, and the prognostic power of several reporter biomolecules, including KAT2B, PCNA, CD86, miR-192-5p and miR-215-5p was also demonstrated. In this study, we reported valuable data for further experimental and clinical efforts, because the proposed biomolecules have significant potential as systems biomarkers for screening or therapeutic purposes in cervical carcinoma.

Exosomal miRNAs as novel cancer biomarkers: Challenges and opportunities

A biomarker with high specificity and sensitivity, is a basic requirement for non-invasive cancer diagnosis. Exosomes are a type of lipid bilayer extracellular vesicles (EVs), containing different components, including proteins, lipids, DNA, messenger RNA (mRNA), and non-coding RNAs. Increasing evidence indicates that nucleic acids are protected by exosome lipid membrane. These vesicles are almost released from all cell types, into biological fluids. In cancer, the expression of microRNAs (miRNAs), located in the tumor cell-derived exosomes, is deregulated and it could be led to metastasis and therapy resistance. Due to the presence of exosomes in various body fluids and the stability of miRNAs in exosomes, exosomal miRNAs can provide a new class of biomarkers for early and minimally invasive cancer diagnosis. In this article, we review the miRNAs and their roles in cancer. Furthermore, we explain the different types of EVs, especially exosomes, and their functional roles in cancer. At the end, we discuss about the importance of exosomal miRNAs for cancer diagnosis. As well as, we briefly summarize the exosome isolation techniques and obstacles, limiting the clinical applications of exosomal miRNAs.

The novel strategies for next-generation cancer treatment: miRNA combined with chemotherapeutic agents for the treatment of cancer

Medical practitioners are recommending combination therapy in cancer for its various advantages. Combination therapy increases the efficacy of treatment due to its synergistic effects in cancer treatment. In this post-genomic era, microRNAs (miRNAs) are receiving attention for their role in human disease and disease therapy. In this review, we discuss the combination of miRNAs and chemotherapeutic agents for cancer treatment. Moreover, we attempted to portray the role of miRNAs in cancer therapy; outline combination therapy, especially chemo-combination therapy, and discuss the basis for miRNA-based chemo-combination therapies and chemo-combination therapy with miRNA for cancer treatment.

Serum MicroRNA Signature Predicts Response to High-Dose Radiation Therapy in Locally Advanced Non-Small Cell Lung Cancer

PURPOSE

To assess the utility of circulating serum microRNAs (c-miRNAs) to predict response to high-dose radiation therapy for locally advanced non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

Data from 80 patients treated from 2004 to 2013 with definitive standard- or high-dose radiation therapy for stages II-III NSCLC as part of 4 prospective institutional clinical trials were evaluated. Pretreatment serum levels of 62 miRNAs were measured by quantitative reverse transcription-polymerase chain reaction array. We combined miRNA data and clinical factors to generate a dose-response score (DRS) for predicting overall survival (OS) after high-dose versus standard-dose radiation therapy. Elastic net Cox regression was used for variable selection and parameter estimation. Model assessment and tuning parameter selection were performed through full cross-validation. The DRS was also correlated with local progression, distant metastasis, and grade 3 or higher cardiac toxicity using Cox regression, and grade 2 or higher esophageal and pulmonary toxicity using logistic regression.

RESULTS

Eleven predictive miRNAs were combined with clinical factors to generate a DRS for each patient. In patients with low DRS, high-dose radiation therapy was associated with significantly improved OS compared to treatment with standard-dose radiation therapy (hazard ratio 0.22). In these patients, high-dose radiation also conferred lower risk of distant metastasis and local progression, although the latter association was not statistically significant. Patients with high DRS exhibited similar rates of OS regardless of dose (hazard ratio 0.78). The DRS did not correlate with treatment-related toxicity.

CONCLUSIONS

Using c-miRNA signature and clinical factors, we developed a DRS that identified a subset of patients with locally advanced NSCLC who derive an OS benefit from high-dose radiation therapy. This DRS may guide dose escalation in a patient-specific manner.

Screening and identification of four serum miRNAs as novel potential biomarkers for cured pulmonary tuberculosis

Rapid and efficient methods for the determination of cured pulmonary tuberculosis (TB) are lacking. We screened serum miRNAs using the Solexa sequencing method among untreated TB patients, two-month treated TB patients, cured TB patients, and healthy controls. A total of 100 differentially expressed miRNAs were identified in cured TB patients, including 37 up-regulated (fold change >1.50, P < 0.05) and 63 down-regulated (fold change <0.60, P < 0.05) miRNAs. Gene ontology (GO) enrichment analysis revealed that most of the predicted genes were present in the nucleus with a strong protein binding function. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis strongly suggested alterations in the metabolic pathways. Following quantitative real time chain reaction (qRT-PCR), significantly reduced expression levels of miR-21-5p (0.30, P < 0.001), miR-92a-3p (0.63, P < 0.001), and miR-148b-3p (0.17, P < 0.001) were found in the cured TB patients compared with the untreated TB patients, while significantly increased expression levels of miR-21-5p (2.09, P = 0.001), miR-92a-3p (1.40, P = 0.005), and miR-148b-3p (4.80, P = 0.003) were found in the untreated TB patients compared with the healthy controls. And significantly increased level of miR-125a-5p was found between two-month treated TB patients and untreated TB patients (1.81, P = 0.004). We established a cured TB model with 83.96% accuracy by four miRNAs (miR-21-5p, miR-92a-3p, miR-148b-3p, and miR-125a-5p), and also established a diagnostic model with 70.09% accuracy. Our study provides experimental data for establishing objective indicators of cured TB, and also provides a new experimental basis to understand the pathogenesis and prognosis of TB.

miR-92a Inhibits Proliferation and Induces Apoptosis by Regulating Methylenetetrahydrofolate Dehydrogenase 2 (MTHFD2) Expression in Acute Myeloid Leukemia

Aberrant expression of microRNA-92a (miR-92a) has been investigated in various cancers. However, the function and mechanism of miR-92a in acute myeloid leukemia (AML) remain to be elucidated. Our data showed that miR-92a was evidently downregulated and methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) was remarkably upregulated in AML cell lines HL-60 and THP-1. Dual luciferase reporter assay revealed that MTHFD2 was a direct target of miR-92a. Gain- and loss-of-function analysis demonstrated that MTHFD2 knockdown or miR-92a overexpression notably inhibited proliferation and promoted apoptosis of AML cell lines. Restoration of MTHFD2 expression reversed proliferation inhibition and apoptosis induction of AML cells triggered by miR-92a. Moreover, an implanted tumor model in mice indicated that miR-92a overexpression dramatically decreased tumor growth and MTHFD2 expression in vivo. Taken together, our results suggest that miR-92a inhibits proliferation and induces apoptosis by directly regulating MTHFD2 expression in AML. miR-92a may act as a tumor suppressor in AML, providing a promising therapeutic target for AML patients.

MicroRNA-92a promotes cell viability and invasion in cervical cancer via directly targeting Dickkopf-related protein 3

MicroRNA-92a (miR-92a) was recently reported to have an oncogenic role in cervical cancer; however, the underlying mechanism remains largely unclear. The present study aimed to investigate the expression, clinical significance and regulatory mechanism of miR-92a in cervical cancer. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) data indicated that miR-92a was significantly upregulated in cervical cancer tissues compared with matched adjacent non-tumor tissues (P<0.01). High expression of miR-92a was significantly associated with poor differentiation (P=0.031), advanced clinical stage (P=0.011) and lymph node metastasis (P=0.014), but not associated with age, tumor size and distant metastasis. Knockdown of miR-92a significantly inhibited the viability and invasion of cervical cancer HeLa cells, while overexpression of miR-92a significantly enhanced HeLa cell viability and invasion (P<0.01). Luciferase reporter assay identified Dickkopf-related protein 3 (DKK3) as a target gene of miR-92a, and the protein expression of DKK3 was negatively regulated by miR-92a in HeLa cells. Furthermore, overexpression of DKK3 significantly eliminated the stimulative effects of miR-92a on HeLa cell viability and invasion (P<0.01). Additionally, DKK3 was significantly downregulated in cervical cancer tissues compared with adjacent non-tumor tissues (P<0.01), inversely correlated to the miR-92a levels in cervical cancer tissues (P<0.01). In summary, the present study indicated that miR-92a promotes cell viability and invasion in cervical cancer, partly at least, via inhibiting the protein expression of DKK3. Therefore, the present study highlights the clinical significance of the miR-92a/DKK3 axis in cervical cancer.

Effective Integration of Targeted Tumor Imaging and Therapy Using Functionalized InP QDs with VEGFR2 Monoclonal Antibody and miR-92a Inhibitor

Rapid diagnosis and targeted drug treatment require agents that possess multiple functions. Nanomaterials that facilitate optical imaging and direct drug delivery have shown great promise for effective cancer treatment. In this study, we first modified near-infrared fluorescent indium phosphide quantum dots (InP QDs) with a vascular endothelial growth factor receptor 2 (VEGFR2) monoclonal antibody to afford targeted drug delivery function. Then, a miR-92a inhibitor, an antisense microRNA that enhances the expression of tumor suppressor p63, was attached to the VEGFR2-InP QDs via electrostatic interactions. The functionalized InP nanocomposite (IMAN) selectively targets tumor sites and allows for infrared imaging in vivo. We further explored the mechanism of this active targeting. The IMAN was endocytosed and delivered in the form of microvesicles via VEGFR2-CD63 signaling. Moreover, the IMAN induced apoptosis of human myelogenous leukemia cells through the p63 pathway in vitro and in vivo. These results indicate that the IMAN may provide a new and promising chemotherapy strategy against cancer cells, particularly by its active targeting function and utility in noninvasive three-dimensional tumor imaging.

Inducing Apoptosis and Decreasing Cell Proliferation in Human Acute Promyelocytic Leukemia Through Regulation Expression of CASP3 by Let-7a-5p Blockage

MicroRNAs (miRNAs) are short and single strand non-coding RNAs that involved in post-transcriptional regulation of gene expression. Dysregulation of miRNA expression is important event in the many of malignant diseases. Up-regulation of Let-7a-5p expression in acute myeloid leukemia in human in previous studies was reported. In this study blockage of Let-7a-5p in human acute promyelocytic leukemia cell line (HL60) was done by using locked nucleic acid (LNA) method and subsequently expression of Let-7a-5p, cell proliferation, apoptosis, necrosis, and CASP3 expression was measured. At three time points 24, 48 and 72 h after LNA anti- Let-7a-5p transfection, assessment of Let-7a-5p expression by qRT real-time PCR was completed. The MTT assay and annexin/PI staining have been performed. Also, CASP3 expression at different time points after LNA anti-Let-7a-5p transfection in HL60 cell line was measured. The results at three-time points after LNA transfection were represented that Let-7a-5p expression was lower in the LNA-anti-Let-7a group compared to the control groups. The cell viability significantly was different between LNA-anti-Let-7a group and control groups. Increasing apoptotic ratio was associated with Let-7a-5p blockage in the LNA-anti-Let-7a group compared with control groups. Also, the necrotic ratio was higher in the LNA-anti-Let-7a group rather than the other groups. Western blotting revealed that CASP3 expression associated with Let-7a-5p inhibition. Our results displayed that blockage of Let-7a-5p can reduced cell viability mainly due to the induction of apoptosis and CASP3 up-regulation in HL60 cells. These results can be useful in translational medicine for research of antisense therapy in leukemia.

MicroRNA-92a Promotes Cell Proliferation in Cervical Cancer via Inhibiting p21 Expression and Promoting Cell Cycle Progression

MicroRNA-92a (miR-92a) generally plays a promoting role in human cancers, but the underlying mechanism in cervical cancer remains unclear. Here we studied the expression and clinical significance of miR-92a in cervical cancer, as well as the regulatory mechanism in the proliferation of cervical cancer cells. Our data indicated that miR-92a was significantly upregulated in cervical cancer tissues compared to their matched adjacent nontumor tissues (ANTs), and the increased miR-92a levels were significantly associated with a higher grade, lymph node metastasis, and advanced clinical stage in cervical cancer. In vitro study revealed that inhibition of miR-92a led to a significant reduction in the proliferation of HeLa cells via induction of cell cycle arrest at the G₁ stage. In contrast, overexpression of miR-92a markedly promoted the proliferation of HeLa cells by promoting cell cycle progression. Further investigation revealed that miR-92a has a negative effect on protein levels, but not the mRNA levels, of p21 in HeLa cells, suggesting that p21 is a direct target of miR-92a. Overexpression of p21 eliminated the promoting effects of miR-92a on the proliferation and cell cycle progression of HeLa cells. However, knockdown of p21 reversed the suppressive effects of miR-92a downregulation on HeLa cell proliferation and cell cycle progression. Moreover, p21 was significantly downregulated in cervical cancer tissues compared to ANTs, suggesting that the increased expression of miR-92a may contribute to the decreased expression of p21, which further promotes cervical cancer growth. In conclusion, our study demonstrates that miR-92a promotes the proliferation of cervical cancer cells via inhibiting p21 expression and promoting cell cycle progression, highlighting the clinical significance of miR-92a in cervical cancer.

Locked nucleic acid anti-miR-21 inhibits cell growth and invasive behaviors of a colorectal adenocarcinoma cell line: LNA-anti-miR as a novel approach

Colorectal cancer (CRC) is the third leading cause of cancer-related death and has an extremely poor prognosis. Dysregulation of microRNAs (miRNAs) has been shown to be involved in the pathogenesis and progression of many malignancies. Recent data suggest that microRNA-21 (miR-21) is significantly elevated in different types of cancer, especially colon adenocarcinoma. Against this background, locked nucleic acid (LNA)-modified oligonucleotides have recently been suggested as a novel approach for targeting miRNAs as antisense-based gene silencing. The aim of the current study was to explore the functional role of LNA-anti-miR-21 in a colon adenocarcinoma LS174T cell line. LS174T cells were transfected with LNA-anti-miR-21 for 24, 48 and 72 h. Quantitative real-time reverse transcriptase-PCR (qRT-PCR) was performed to assess miR-21 expression by LNA-anti-miR-21. The viability of the cells was evaluated by MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide) assay and Annexin V/propidium iodide staining assay was used to detect apoptosis. Moreover, invasive behavior of the cells was evaluated before and after therapy by transwell assay. LNA-anti-miR-21 was successfully transfected in human LS174T cells and suppressed the endogenous miR-21. LNA-anti-miR-21 inhibited the cells' growth followed by induction of apoptosis. LNA-anti-miR-21 (50 pmol/μl) reduced the invasive behaviors of LS174T cells after 24 h, compared with untreated cells and scrambled LNA-transfected cells. However, this effect was more pronounced after 72 h. Our findings suggest the therapeutic potential of LNA-anti-miR-21 in a colon adenocarcinoma for targeting miR-21 expression. Further studies are warranted to investigate the molecular mechanisms underlying this novel inhibitor in colorectal cancer to establish its potential value for treatment of CRC patients with high miR-21 expression.

Locked nucleic acid inhibits miR-92a-3p in human colorectal cancer, induces apoptosis and inhibits cell proliferation

MicroRNAs (miRNAs) are a type of small noncoding RNAs that have a vital role in basic biological processes such as cellular growth, division and apoptosis. A change in the expression of miRNAs can induce many diseases. Recently, the role of miRNA in some of the cancers as a tumor suppressor and oncogene has been recognized. Several studies have proved that miR-92a-3p acts as an oncogene in colorectal cancer (CRC). We studied CRC by inhibiting miR-92a-3p in SW48 cells (human colorectal cancer cell line) that were transfected with locked nucleic acid (LNA). At different times, the expression level of miR-92a-3p, cell vitality, apoptosis and necrosis were studied by qRT-PCR, MTT, Annexin-V and propidiumiodide. Our results showed that the expression of miR-92a-3p and proliferation of SW48 cells were decreased, and also a high percentage of SW48 cells were exposed to apoptosis and necrosis (P⩽0.005). Our study showed that the inhibition of miR-92a-3p with LNA inhibited cell proliferation and induced apoptosis and necrosis in CRC.