MicroRNA expression and function in cancer

MicroRNA-7 Regulates Migration and Chemoresistance in Non-Hodgkin Lymphoma Cells Through Regulation of KLF4 and YY1

The discovery and description of the role of microRNAs has become very important, specifically due to their participation in the regulation of proteins and transcription factors involved in the development of cancer. microRNA-7 (miR-7) has been described as a negative regulator of several proteins involved in cancer, such as YY1 and KLF4. We have recently reported that YY1 and KLF4 play a role in non-Hodgkin lymphoma (NHL) and that the expression of KLF4 is regulated by YY1. Therefore, in this study we analyzed the role of miR-7 in NHL through the negative regulation of YY1 and KLF4. qRT-PCR showed that there is an inverse expression of miR-7 in relation to the expression of YY1 and KLF4 in B-NHL cell lines. The possible regulation of YY1 and KLF4 by miR-7 was analyzed using the constitutive expression or inhibition of miR-7, as well as using reporter plasmids containing the 3 'UTR region of YY1 or KLF4. The role of miR-7 in NHL, through the negative regulation of YY1 and KLF4 was determined by chemoresistance and migration assays. We corroborated our results in cell lines, in a TMA from NHL patients including DLBCL and follicular lymphoma subtypes, in where we analyzed miR-7 by ISH and YY1 and KLF4 using IHC. All tumors expressing miR-7 showed a negative correlation with YY1 and KLF4 expression. In addition, expression of miR-7 was analyzed using the GEO Database; miR-7 downregulated expression was associated with pour overall-survival. Our results show for the first time that miR-7 is implicate in the cell migration and chemoresistance in NHL, through the negative regulation of YY1 and KLF4. That also support the evidence that YY1 and KLF4 can be a potential therapeutic target in NHL.

Hsa_circ_0081534 increases the proliferation and invasion of nasopharyngeal carcinoma cells through regulating the miR-508-5p/FN1 axis

Accumulating lines of evidence indicate that circular RNAs (circRNAs) are involved in the pathogenesis of human cancers, including nasopharyngeal carcinoma (NPC). However, the influences of hsa_circ_0081534 upon the pathogenesis and dynamics of NPC are undescribed. In this study, we identified a circRNA hsa_circ_0081534 was significantly upregulated in NPC tissues and cell lines. Inhibition of hsa_circ_0081534 induced a decrease in NPC cells proliferation and invasion in vitro, and repressed tumor growth in vivo. In mechanism, hsa_circ_0081534 promoted NPC progression by sponging miR-508-5p. Fibronectin 1 (FN1) is a target gene of miR-508-5p. In addition, rescue assays showed that FN1 overexpression (or miR-508-5p inhibitors) abolished the roles of hsa_circ_0081534 inhibition on NPC cells proliferation and invasion. Therefore, hsa_circ_0081534 promoted the proliferation, and invasion of NPC cells via regulating the miR-508-5p/FN1 axis. Our findings suggested that hsa_circ_0081534 could be a novel therapeutic target for the treatment of NPC patients.

MicroRNA-663 Regulates Melanoma Progression by Inhibiting FHL3

microRNA-663a (miR-663a) was reported to be highly expressed in cancers. However, its roles in melanoma progression remain unclear. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was conducted to measure miR-663a expression level in melanoma cell lines and normal cells. Cell counting kit-8 assay, wound-healing assay, and transwell invasion assay were conducted to analyze biological roles of miR-663a in melanoma. Luciferase activity reporter assay was conducted to validate the connection of miR-663a and Four and a half LIM domain (FHL) protein 3 (FHL3) in melanoma. Our results showed miR-663a expression level was significantly increased in melanoma cells compared with normal cells. Silencing miR-663a expression suppresses melanoma cell proliferation, migration, and invasion in vitro. Moreover, FHL3 was validated as a functional target of miR-663a. Knockdown of FHL3 partially rescued the inhibitory effects of miR-663a inhibitor on melanoma cell behaviors. Together, our work provided evidence that miR-663a functions as an oncogenic miRNA in melanoma.

MiR-128 suppresses metastatic capacity by targeting metadherin in breast cancer cells

Background

Breast cancer, the most common cancer in women worldwide, causes the vast majority of cancer-related deaths. Undoubtedly, tumor metastasis and recurrence are responsible for more than 90 percent of these deaths. MicroRNAs are endogenous noncoding RNAs that have been integrated into almost all the physiological and pathological processes, including metastasis. In the present study, the role of miR-128 in breast cancer was investigated.

Results

Compared to the corresponding adjacent normal tissue, the expression of miR-128 was significantly suppressed in human breast cancer specimens. More importantly, its expression level was reversely correlated to histological grade of the cancer. Ectopic expression of miR-128 in the aggressive breast cancer cell line MDA-MB-231 could inhibit cell motility and invasive capacity remarkably. Afterwards, Metadherin (MTDH), also known as AEG-1 (Astrocyte Elevated Gene 1) and Lyric that implicated in various aspects of cancer progression and metastasis, was further identified as a direct target gene of miR-128 and its expression level was up-regulated in clinical samples as expected. Moreover, knockdown of MTDH in MDA-MB-231 cells obviously impaired the migration and invasion capabilities, whereas re-expression of MTDH abrogated the suppressive effect caused by miR-128.

Conclusions

Overall, these findings demonstrate that miR-128 could serve as a novel biomarker for breast cancer metastasis and a potent target for treatment in the future.

MicroRNAs: potential biomarkers for diagnosis and prognosis of different cancers

A thorough understanding of the tumor environment and underlying genetic factors helps in the better formulation of cancer management strategies. Availability of efficient diagnostic and prognostic biomarkers facilitates early detection and progression of the disease. MicroRNAs affect different biological processes participating in tumorigenesis through regulation of their target genes. An expanding list of unique RNAs and understanding of their regulatory role has opened up a new field in cancer research. Based on a comprehensive literature search, we identified 728 miRNAs dysregulated in sixteen cancer types namely bladder cancer (BC), breast cancer (BrC), cervical cancer (CC), colorectal cancer (CRC), esophageal cancer (EC), endometrial cancer (EnC), gastric cancer (GC), hepatocellular cancer (HCC), head and neck squamous cell cancer (HNSCC), lung cancer (LC), ovarian cancer (OC), pancreatic cancer (PC), prostate cancer (PrC), renal cell cancer (RCC), skin cancer (SC), and thyroid cancer (TC). Expression of 43 miRNAs was either upregulated or downregulated in six or more of these cancers. Finally, seven miRNAs namely mir-18a, mir-21, mir-143/145, mir-210, mir-218, mir-221, showing maximum dysregulation, either up- or down-regulation in the majority of cancers, were selected for a detailed presentation of their expression and evaluation of their potential as biomarkers in the diagnosis and prognosis of different cancers.

PGAM1, regulated by miR-3614-5p, functions as an oncogene by activating transforming growth factor-β (TGF-β) signaling in the progression of non-small cell lung carcinoma

Phosphoglycerate mutase 1 (PGAM1) is a recently identified key catalytic enzyme in aerobic glycolysis. Recent literature has documented that dysregulated PGAM1 expression is associated with tumorigenesis in various cancers. However, the expression status and biological function of PGAM1 in non-small-cell lung cancer (NSCLC) are poorly elucidated. In this study, we found that PGAM1 was overexpressed in NSCLC tissues and that high expression of PGAM1 was associated with poor prognosis in NSCLC patients. Functionally, gain- and loss-of-function analysis showed that PGAM1 promoted proliferation and invasion in vitro, and facilitated tumor growth in vivo. Mechanistically, the transforming growth factor-β (TGF-β) signaling pathway was also markedly impaired in response to PGAM1 silencing. Additionally, we verified that PGAM1 was inhibited by miR-3614-5p via direct targeting of its 3’-untranslated regions in a hypoxia-independent manner. Furthermore, overexpression of miR-3614-5p attenuated NSCLC cell proliferation and invasion, and these effects could be partially reversed by reintroduction of PGAM1. Conclusively, our results suggest that the miR-3614-5p/PGAM1 axis plays a critical role during the progression of NSCLC, and these findings may provide a potential target for the development of therapeutic strategies for NSCLC patients.

Combinatory Treatment with miR-7-5p and Drug-Loaded Cubosomes Effectively Impairs Cancer Cells

BACKGROUND

Multidrug resistance (MDR) is an emerging problem in the treatment of cancer. Therefore, there is a necessity for novel strategies that would sensitize tumor cells to the administered chemotherapeutics. One of the innovative approaches in fighting drug-resistant tumors is the treatment of cancer with microRNA (miRNA), or the use of cubosomes (lipid nanoparticles) loaded with drugs. Here, we present a study on a novel approach, which combines both tools.

METHODS

Cubosomes loaded with miR-7-5p and chemotherapeutics were developed. The effects of drug- and miRNA-loaded vehicles on glioma- (A172, T98G), papillary thyroid- (TPC-1) and cervical carcinoma-derived (HeLa) cells were analyzed using molecular biology techniques, including quantitative real-time PCR, MTS-based cell proliferation test, flow cytometry and spheroids formation assay.

RESULTS

The obtained data indicate that miR-7-5p increases the sensitivity of the tested cells to the drug, and that nanoparticles loaded with both miRNA and the drug produce a greater anti-tumor effect in comparison to the free drug treatment. It was found that an increased level of apoptosis in the drug/miRNA co-treated cells is accompanied by an alternation in the expression of the genes encoding for key MDR proteins of the ABC family.

CONCLUSIONS

Overall, co-administration of miR-7-5p with a chemotherapeutic can be considered a promising strategy, leading to reduced MDR and the induction of apoptosis in cancer cells.

The roles of miRNAs' clinical efficiencies in the colorectal cancer pathobiology: A review article

MiRNAs (microRNAs) are defined as micro directors and regulators of gene expression. Since altered miRNA expression is signified in the pathobiology of diverse cancers such as colorectal cancers (CRCs), these molecules are described as therapeutic targets, either. Manipulation of miRNAs could lead to further therapy for chemo and radio-resistant CRCs. The usage of microRNAs has indicated prominent promise in the prognosis and diagnosis of CRC, because of their unique expression pattern associated with cancer types and malignancies. Nowadays, many researchers are analyzing the correlation between miRNA polymorphisms and cancer risk. With continuous incompatibility in colorectal cancer (CRC) miRNAs expression data, it is critical to move toward the content of a "pre-laboratory" analysis to speed up efficient accuracy medicine and translational study. Pathway study for the highest expressed miRNAs- regulated target genes resulted in the identification of a considerable number of genes associated with CRC pathway including PI3K, TGFβ, and APC. In this review, we aimed to collect fruitful information about miRNAs and their potential roles in CRC, and provide a meta-analysis of the most frequently studied miRNAs in association with the disease.

Enhancement of Breast Cancer Cell Aggressiveness by lncRNA H19 and its Mir-675 Derivative: Insight into Shared and Different Actions

Breast cancer is a major public health problem and the leading world cause of women death by cancer. Both the recurrence and mortality of breast cancer are mainly caused by the formation of metastasis. The long non-coding RNA H19, the precursor of miR-675, is involved in breast cancer development. The aim of this work was to determine the implication but, also, the relative contribution of H19 and miR-675 to the enhancement of breast cancer metastatic potential. We showed that both H19 and miR-675 increase the invasive capacities of breast cancer cells in xenografted transgenic zebrafish models. In vitro, H19 and miR-675 enhance the cell migration and invasion, as well as colony formation. H19 seems to induce the epithelial-to-mesenchymal transition (EMT), with a decreased expression of epithelial markers and an increased expression of mesenchymal markers. Interestingly, miR-675 simultaneously increases the expression of both epithelial and mesenchymal markers, suggesting the induction of a hybrid phenotype or mesenchymal-to-epithelial transition (MET). Finally, we demonstrated for the first time that miR-675, like its precursor H19, increases the stemness properties of breast cancer cells. Altogether, our data suggest that H19 and miR-675 could enhance the aggressiveness of breast cancer cells through both common and different mechanisms.

Long-Term Detection of Oncogenic MicroRNA in Living Human Cancer Cells by Gold@ Polydopamine-Shell Nanoprobe

Oncogenic microRNAs (miRNA), for example, miR-155, are key tumor biomarkers in cancer cells that drive tumorigenesis, and the miRNA profile signature can predict cancer development and aggressiveness. Hence, timely detection of oncogenic miRNA in living cells is highly attractive to the diagnosis of cancer at an early stage. Herein, we report a highly sequence-specific gold@polydopamine-based nanoprobe for long-term detection of miRNA in human cancer cell lines in vitro. A single administration of the nanoprobe enables continuous detection of the miR-155 expression level in living cancer cells for up to 5 days. We believe that our nanoprobe is highly promising for both oncology research and translational applications.

LncRNA LINC00152 Increases the Aggressiveness of Human Retinoblastoma and Enhances Carboplatin and Adriamycin Resistance by Regulating MiR-613/Yes-Associated Protein 1 (YAP1) Axis

BACKGROUND Long noncoding RNA (lncRNA) acts as key regulator in human cancers, including retinoblastoma. However, the function of LINC00152 remains largely unknown in retinoblastoma. Thus, this study aimed to explore the role and molecular mechanisms of LINC00152 in retinoblastoma. MATERIAL AND METHODS The real-time quantitative polymerase chain reaction (RT-qPCR) was used to quantify the expression levels of LINC00152, miR-613 and yes-associated protein 1 (YAP1). The target genes of LINC00152 and miR-613 were identified by dual-luciferase reporter analysis, RNA immunoprecipitation (RIP) and RNA pulldown assays. The viability, apoptosis, and invasion of retinoblastoma cells were assessed by Cell Counting Kit-8, flow cytometry, and Transwell assays, respectively. In addition, western blot was used to test the protein expression in retinoblastoma cells or tissues. Cell sensitivity to carboplatin and adriamycin was analyzed by computing IC₅₀ value. The effects of LINC00152 silencing in vivo were measured by a xenograft experiment. RESULTS LINC00152 was obviously upregulated, while miR-613 was decreased in retinoblastoma tissues and cells. MiR-613, a target of LINC00152, was negatively regulated by LINC00152. Functional experiment further illustrated that silencing of LINC00152 evidently repressed proliferation, invasion, and autophagy while reinforced apoptosis of retinoblastoma cells, besides, retinoblastoma cells were more sensitive to carboplatin and adriamycin after knockdown of LINC00152. Importantly, knockdown of LINC00152-induced effects on retinoblastoma cells could be overturned by introducing miR-613 inhibitor. Downregulation of miR-613 abolished silencing of YAP1-effects on proliferation, apoptosis, invasion, autophagy, and chemoresistance of retinoblastoma cells. The results of the xenograft experiment indicated that LINC00152 silencing impeded tumor growth in vivo. CONCLUSIONS Mechanistically, LINC00152 enhanced the aggressiveness of retinoblastoma and boosted carboplatin and adriamycin resistance by regulating YAP1 by sponging miR-613 in human retinoblastoma.

MicroRNAs and Adrenocortical Tumors: Where do we Stand on Primary Aldosteronism?

MicroRNAs, the endogenous mediators of RNA interference, interact with the renin-angiotensin-aldosterone system, regulate aldosterone secretion and aldosterone effects. Some novel data show that the expression of some microRNAs is altered in primary aldosteronism, and some of these appear to have pathogenic relevance, as well. Differences in the circulating microRNA expression profiles between the two major forms of primary aldosteronism, unilateral aldosterone-producing adenoma and bilateral adrenal hyperplasia have also been shown. Here, we present a brief synopsis of these findings focusing on the potential relevance of microRNA in primary aldosteronism.

Pancreatic neuroendocrine tumors: A review of serum biomarkers, staging, and management

Pancreatic neuroendocrine tumors (pNETs) are a heterogeneous group of tumors with complicated treatment options that depend on pathological grading, clinical staging, and presence of symptoms related to hormonal secretion. With regard to diagnosis, remarkable advances have been made: Chromogranin A is recommended as a general marker for pNETs. But other new biomarker modalities, like circulating tumor cells, multiple transcript analysis, microRNA profile, and cytokines, should be clarified in future investigations before clinical application. Therefore, the currently available serum biomarkers are insufficient for diagnosis, but reasonably acceptable in evaluating the prognosis of and response to treatments during follow-up of pNETs. Surgical resection is still the only curative therapeutic option for localized pNETs. However, a debulking operation has also been proven to be effective for controlling the disease. As for drug therapy, steroids and somatostatin analogues are the first-line therapy for those with positive expression of somatostatin receptor, while everolimus and sunitinib represent important progress for the treatment of patients with advanced pNETs. Great progress has been achieved in the combination of systematic therapy with local control treatments. The optimal timing of local control intervention, planning of sequential therapies, and implementation of multidisciplinary care remain pending.

miRNAs, oxidative stress, and cancer: A comprehensive and updated review

Oxidative stress refers to elevated levels of intracellular reactive oxygen species (ROS). ROS homeostasis functions as a signaling pathway for normal cell survival and appropriate cell signaling. Chronic inflammation induced by imbalanced levels of ROS contributes to many diseases and different types of cancer. ROS can alter the expression of oncogenes and tumor suppressor genes through epigenetic modifications, transcription factors, and non-coding RNAs. MicroRNAs (miRNAs) are small non-coding RNAs that play a key role in most biological pathways. Each miRNA regulates hundreds of target genes by inhibiting protein translation and/or promoting messenger RNA degradation. In normal conditions, miRNAs play a physiological role in cell proliferation, differentiation, and apoptosis. However, different factors that can dysregulate cell signaling and cellular homeostasis can also affect miRNA expression. The alteration of miRNA expression can work against disturbing factors or mediate their effects. Oxidative stress is one of these factors. Considering the complex interplay between ROS level and miRNA regulation and both of these with cancer development, we review the role of miRNAs in cancer, focusing on their function in oxidative stress.

Effects of gE/gI deletions on the miRNA expression of PRV-infected PK-15 cells

Pseudorabies virus (PRV) belongs to the Alphaherpesvirinae subfamily of Herpesviridae. PRV-induced pseudorabies is a highly contagious disease that has caused huge economic losses to the global swine industry. The PRV gE/gI gene deletion vaccine strain (Fa ΔgE/gI strain) constructed from the PRV Fa wild-type strain was shown to have a protective effect against infection. However, the interaction between PRV gE/gI genes and host miRNA needs further exploration, and little is known about the regulatory mechanisms of non-coding RNAs during PRV infection. miRNAs play a key regulatory role in viral infection and immune responses, so we analyzed the differential expression of miRNAs induced by the PRV Fa ΔgE/gI strain and Fa wild-type strain in the PK15 cell line. High-throughput sequencing reads were aligned to known Sus scrofa pre-miRNAs in the miRBase database. Target genes of differentially expressed miRNAs were predicted using the miRGen 3.0 database, then filtered miRNA target genes were subjected to Gene Ontology (GO) analysis and Search Tool for the Retrieval of Interacting Genes/ Proteins (STRING) analysis. Stem-loop quantitative real-time PCR was performed to confirm the accuracy of high-throughput sequencing data. In total, 387, 472, and 490 annotated and novel mature miRNAs were identified from PRV Fa ΔgE/gI strain-infected, Fa wild-type strain-infected, and non-infected PK-15 cells, respectively. Five PRV-encoded miRNAs were also identified. GO analysis showed that target genes of differentially expressed miRNAs in PRV Fa ΔgE/gI strain-infected and Fa wild-type strain-infected PK-15 cells were mainly involved in biological regulation and metabolic processes. STRING analysis showed that immune-related target genes of differentially expressed miRNAs in the Toll-like receptor signaling pathway, B cell receptor signaling pathway, T cell receptor signaling pathway, nuclear factor-κB signaling pathway, and transforming growth factor-β signaling pathway were interrelated. This is the first report of the small RNA transcriptome in PRV mutant wild-type strain-infected and Fa ΔgE/gI strain-infected porcine cell lines. Our findings will contribute to the prevention and treatment of PRV mutant strains.

MiR-181a functions as an oncogene by regulating CCND1 in multiple myeloma

MicroRNA-181a (miR-181a) has been demonstrated to be upregulated in patients with multiple myeloma (MM). In several studies, miR-181a has been demonstrated to be significantly overexpressed in MM; however, its potential role in development and progression of MM remains unknown. In the present study, the functions of miR-181a and the potential underlying molecular mechanisms in the pathogenesis of MM were examined. Increased expression of miR-181a was observed in bone marrow samples from patients with MM and the MM RPMI8226 cell line. The role of miR-181a was examined and it was demonstrated that it participated in the proliferation and migration processes of the MM cell line. Furthermore, it was demonstrated that the downregulation of miR-181a inhibited the expression of CCND1, a cell cycle regulatory gene, and caused cell cycle arrest in MM cells. The results of the present study suggested that miR-181a functions as an onco-miRNA in MM, which serves regulatory roles by upregulating expression of CCND1 and may therefore serve as a potential target in patients with MM.

The importance of interaction between MicroRNAs and gut microbiota in several pathways

The human gut harbors diverse microbes that play a fundamental role in the well-being of their host. Microbiota disruption affects the immune function, metabolism, and causes several diseases. Therefore, understanding how the microbiome is adjusted, and identifying methods for manipulating it is critical. Studies have found that there is an inverse association between MicroRNAs (miRNAs) abundance and microbe abundance. miRNAs are known to be engaged in post-transcription regulation of cell-autonomous gene expression. Recently, they have gained great attention for their proposed roles in cell-to-cell communication, and as biomarkers for human disease. Here, we review recent studies on the role of miRNAs as a component of outer membrane vesicles (OMVs) in the composition of gut microbiota and their significance in the human situation of health and diseases and discuss their effect on inflammatory responses and dysbiosis. Further, we explain how probiotics exert influence on the expression of miRNAs.

HEG1-responsive microRNA-23b regulates cell proliferation in malignant mesothelioma cells

Malignant mesothelioma (MM) is a fatal tumor, and the absence of a specific diagnostic marker and/or a pathogenic molecule-targeting drug is a major issue for its pathological diagnosis and for targeting therapy. The molecular target of MM has not been elucidated because of unknown survival, death, and cytotoxic signals in MM. HEG homolog 1 (HEG1) is a mucin-like membrane protein that contains epidermal growth factor-like domains, and it plays an important role in cancers through aberrant signaling, including that during cell adhesion, as well as through protection from invasion of tumor cells. HEG1 expression supports the survival and proliferation of MM cells. In this study, functional analysis of HEG1 and microRNAs using MM cell lines (H226, MESO4, H2052) was performed. The MTS assay revealed that cell proliferation was significantly reduced upon transient transfection with microRNA-23b (miR-23b) inhibitor and/or HEG1 siRNA. The Annexin V assay revealed that apoptosis was induced upon suppression of miR-23b and/or HEG1. Western blotting showed that the autophagy-related protein LC3-II was induced upon suppression of miR-23b and/or HEG1. These results revealed that miR-23b contributes to HEG1-dependent cell proliferation through evasion of cytotoxicity induced by apoptosis and autophagy in MM cells. HEG1-dependent/mediated miR-23b signaling may therefore be a potential target for MM diagnosis and therapy.

Pseudogene-gene functional networks are prognostic of patient survival in breast cancer

BACKGROUND

Given the vast range of molecular mechanisms giving rise to breast cancer, it is unlikely universal cures exist. However, by providing a more precise prognosis for breast cancer patients through integrative models, treatments can become more individualized, resulting in more successful outcomes. Specifically, we combine gene expression, pseudogene expression, miRNA expression, clinical factors, and pseudogene-gene functional networks to generate these models for breast cancer prognostics. Establishing a LASSO-generated molecular gene signature revealed that the increased expression of genes STXBP5, GALP and LOC387646 indicate a poor prognosis for a breast cancer patient. We also found that increased CTSLP8 and RPS10P20 and decreased HLA-K pseudogene expression indicate poor prognosis for a patient. Perhaps most importantly we identified a pseudogene-gene interaction, GPS2-GPS2P1 (improved prognosis) that is prognostic where neither the gene nor pseudogene alone is prognostic of survival. Besides, miR-3923 was predicted to target GPS2 using miRanda, PicTar, and TargetScan, which imply modules of gene-pseudogene-miRNAs that are potentially functionally related to patient survival.

RESULTS

In our LASSO-based model, we take into account features including pseudogenes, genes and candidate pseudogene-gene interactions. Key biomarkers were identified from the features. The identification of key biomarkers in combination with significant clinical factors (such as stage and radiation therapy status) should be considered as well, enabling a specific prognostic prediction and future treatment plan for an individual patient. Here we used our PseudoFuN web application to identify the candidate pseudogene-gene interactions as candidate features in our integrative models. We further identified potential miRNAs targeting those features in our models using PseudoFuN as well. From this study, we present an interpretable survival model based on LASSO and decision trees, we also provide a novel feature set which includes pseudogene-gene interaction terms that have been ignored by previous prognostic models. We find that some interaction terms for pseudogenes and genes are significantly prognostic of survival. These interactions are cross-over interactions, where the impact of the gene expression on survival changes with pseudogene expression and vice versa. These may imply more complicated regulation mechanisms than previously understood.

CONCLUSIONS

We recommend these novel feature sets be considered when training other types of prognostic models as well, which may provide more comprehensive insights into personalized treatment decisions.

Tumor Suppressor microRNA-138 Suppresses Low-Grade Glioma Development and Metastasis via Regulating IGF2BP2

Background

Low-grade gliomas (LGG), approximately constitute one-third of all types of gliomas, are prone to relapse and metastasis. MicroRNA-138 (miR-138) is reported to be dysregulated in diverse human tumors and mainly function as a tumor suppressor. In this study, we analyzed the expression profile and function of miR-138 in LGG.

Methods

Quantitative PCR (qPCR) and public database bioinformatics analysis were performed to determine the miR-138 levels in LGG. MiR-138 overexpression in LGG cells was achieved by miR-138 mimics transfection. Cell proliferation was assessed by CCK8, EdU and colony formation assays. Cell invasion and migration were analyzed by transwell and wound-healing assays. Xenograft model was employed to study the role of miR-138 in LGG growth in vivo. The target of miR-138 was validated by multiple methods, such as luciferase reporter assay, RT-qPCR and Western blot. Bioinformatics analysis was conducted to explore the molecular mechanisms by which miR-138 contributed to LGG progression.

Results

miR-138 was significantly downregulated in LGG tumor tissues and low expression of miR-138 was significantly associated with poor prognosis as well as relapse and metastasis in LGG patients. Functional analysis indicated that ectopic miR-138 expression suppressed LGG cell growth and invasive phenotype in vitro, and inhibited tumor development in vivo. Moreover, miR-138 directly targeted and repressed insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2) by targeting the 3ʹ-UTR of IGF2BP2, inhibiting epithelial to mesenchymal transition (EMT) to attenuate LGG aggressiveness. In addition, we found that elevated IGF2BP2 expression correlates with poor survival of LGG patients.

Conclusion

miR-138 may function as a tumor inhibitor by directly inhibiting IGF2BP2 and suppressing EMT in the progression of LGG.

Differential Expression of miRNAs in Hypoxia ("HypoxamiRs") in Three Canine High-Grade Glioma Cell Lines

Dogs with spontaneous high-grade gliomas increasingly are being proposed as useful large animal pre-clinical models for the human disease. Hypoxia is a critical microenvironmental condition that is common in both canine and human high-grade gliomas and drives increased angiogenesis, chemo- and radioresistance, and acquisition of a stem-like phenotype. Some of this effect is mediated by the hypoxia-induced expression of microRNAs, small (~22 nucleotides long), non-coding RNAs that can modulate gene expression through interference with mRNA translation. Using an in vitro model with three canine high-grade glioma cell lines (J3T, SDT3G, and G06A) exposed to 72 h of 1.5% oxygen vs. standard 20% oxygen, we examined the global “hypoxamiR” profile using small RNA-Seq and performed pathway analysis for targeted genes using both Panther and NetworkAnalyst. Important pathways include many that are well-established as being important in glioma biology, general cancer biology, hypoxia, angiogenesis, immunology, and stem-ness, among others. This work provides the first examination of the effect of hypoxia on miRNA expression in the context of canine glioma, and highlights important similarities with the human disease.

Inhibition of EZH2 Attenuates Sorafenib Resistance by Targeting NOTCH1 Activation-Dependent Liver Cancer Stem Cells via NOTCH1-Related MicroRNAs in Hepatocellular Carcinoma

Acquired resistance and intrinsic to sorafenib therapy represents a major hurdle in improving the management of advanced hepatocellular carcinoma (HCC), which has been recently shown to be associated with the emergence of liver cancer stem cells (CSCs). However, it remains largely unknown whether and how histone posttranslational modifications, especially H3K27me3, are causally linked to the maintenance of self-renewal ability in sorafenib-resistant HCC. Here, we found that NOTCH1 signaling was activated in sorafenib-resistant HCC cells and NOTCH1 activation conferred hepatoma cells sorafenib resistance through enhanced self-renewal and tumorigenecity. Besides, the overexpression of EZH2 was required for the emergence of cancer stem cells following prolonged sorafenib treatment. As such, modulating EZH2 expression or activity suppressed activation of NOTCH1 pathway by elevating the expression of NOTCH1-related microRNAs, hsa-miR-21-5p and has-miR-26a-1-5p, via H3K27me3, and consequently weakened self-renewal ability and tumorigenecity and restored the anti-tumor effects of sorafenib. Overall, our results highlight the role of EZH2/NICD1 axis, and also suggest that EZH2 and NOTCH1 pathway are rational targets for therapeutic intervention in sorafenib-resistant HCC.

miR-595 suppresses cell proliferation and metastasis in hepatocellular carcinoma by inhibiting NF-κB signalling pathway

MicroRNAs (miRNAs) have been proven to be critical regulators of cancer development. To date, many of them are still in urgent need of characterisation, and role of miR-595 in hepatocellular carcinoma (HCC) remains unknown. To better understand the mechanism of miR-595 in HCC development, a series of experiments were carried out to explore the effects of miR-595 on malignant behaviour in HCC. First, we found that miR-595 was downregulated in HCC tissues and cells and tightly associated with poor overall survival in HCC patients. Then, we further demonstrated that miR-595 inhibited cell proliferation, migration and invasion in vitro. Additionally, animal experimental results demonstrated that miR-595 inhibited HCC carcinogenesis in vivo. Moreover, we demonstrated that upregulation of miR-595 expression inhibited the NF-κB signalling pathway in HCC cells. To further uncover the molecular mechanism of miR-595 action on the NF-κB signalling pathway, we identified ABCB1 as a direct target of miR-595 through bioinformatics prediction and supported our results with luciferase assays. Finally, we showed that miR-595 inhibited the NF-κB pathway by suppressing ABCB1 expression in HCC cells. Taken together, our findings uncover a pivotal role for the miR-595/ABCB1/NF-κB axis in HCC development, and this novel axis may be a suitable target for diagnostic or therapeutic interventions in HCC.

Downregulation of microR-147b represses the proliferation and invasion of thyroid carcinoma cells by inhibiting Wnt/β-catenin signaling via targeting SOX15

microRNA-147b (miR-147b) is a newly identified tumor-related miRNA that is dysregulated in multiple cancer types. Yet, the role of miR-147b in thyroid carcinoma remains unknown. Herein, we found that miR-147b expression was upregulated in thyroid carcinoma tissues and cell lines. miR-147b inhibition decreased the proliferation, colony formation, and invasion of thyroid carcinoma cells. The tumor suppressive gene SRY-related high-mobility-group box gene 15 (SOX15) was predicted as a miR-147b target gene. SOX15 expression was markedly decreased in thyroid carcinoma tissues and inversely correlated with the miR-147b expression. SOX15 overexpression repressed the proliferation and invasion of thyroid carcinoma cells associated with downregulation of Wnt/β-catenin signaling. SOX15 knockdown abolished the miR-147b-inhibition-mediated antitumor effect. miR-147b inhibition or SOX15 overexpression retarded the tumor growth of thyroid carcinoma cells in vivo. Overall, our study suggests that miR-147b inhibition restrains the proliferation and invasion of thyroid carcinoma cells through upregulation of SOX15 and inhibition of Wnt/β-catenin signaling.

Long noncoding RNA DUXAP8 contributes to the progression of hepatocellular carcinoma via regulating miR-422a/PDK2 axis

Background

Hepatocellular carcinoma (HCC) is one of the most deadly cancer worldwide. Multiple long noncoding RNAs (lncRNAs) are recently identified as crucial oncogenic factors or tumor suppressors. In this study, we explored the functon and mechanism of lncRNA double homeobox A pseudogene 8 (DUXAP8) in the progression of HCC.

Methods

Expression levels of DUXAP8 in HCC tissue samples were measured using qRT‐PCR. The association between pathological indexes and the expression of DUXAP8 was also analyzed. Human HCC cell lines SMMC‐7721 and QSG‐7701 were used in in vitro studies. CCK‐8 assay was used to assess the effect of DUXAP8 on HCC cell line proliferation. Scratch healing assay and Transwell assay were conducted to detect the effect of DUXAP8 on migration and invasion. Furthermore, dual‐luciferase reporter assay was used to confirm targeting relationship between miR‐422a and DUXAP8. Additionally, Western blot was used to detect the regulatory function of DUXAP8 on pyruvate dehydrogenase kinase 2 (PDK2).

Results

DUXAP8 expression HCC clinical samples was significantly increased and this was correlated with unfavorable pathological indexes. High expression of DUXAP8 was associated with shorter overall survival time of patients. Its overexpression remarkably facilitated the proliferation, metastasis, and epithelial‐mesenchymal transition of HCC cells. Accordingly, knockdown of it suppressed the malignant phenotypes of HCC cells. Overexpression of DUXAP8 significantly reduced the expression of miR‐422a by sponging it, but enhanced the expression of PDK2.

Conclusions

DUXAP8 was a sponge of tumor suppressor miR‐422a in HCC, enhanced the expression of PDK2 indirectly, and functioned as an oncogenic lncRNA.

Computational annotation of miRNA transcription start sites

Motivation

MicroRNAs (miRNAs) are small noncoding RNAs that play important roles in gene regulation and phenotype development. The identification of miRNA transcription start sites (TSSs) is critical to understand the functional roles of miRNA genes and their transcriptional regulation. Unlike protein-coding genes, miRNA TSSs are not directly detectable from conventional RNA-Seq experiments due to miRNA-specific process of biogenesis. In the past decade, large-scale genome-wide TSS-Seq and transcription activation marker profiling data have become available, based on which, many computational methods have been developed. These methods have greatly advanced genome-wide miRNA TSS annotation.

Results

In this study, we summarized recent computational methods and their results on miRNA TSS annotation. We collected and performed a comparative analysis of miRNA TSS annotations from 14 representative studies. We further compiled a robust set of miRNA TSSs (RSmirT) that are supported by multiple studies. Integrative genomic and epigenomic data analysis on RSmirT revealed the genomic and epigenomic features of miRNA TSSs as well as their relations to protein-coding and long non-coding genes.

Contact

xiaoman@mail.ucf.edu, haihu@cs.ucf.edu

Silencing of microRNA-517a induces oxidative stress injury in melanoma cells via inactivation of the JNK signaling pathway by upregulating CDKN1C

Background

Melanoma is notoriously resistant to current treatments, and less than 25% of metastatic melanoma cases respond to existing therapies. Growing evidence has shown that microRNAs (miRNAs) play a vital role in the prognosis of melanoma. MiR-517a has been implicated in many types of cancer; however, its expressional features and potential biological functions in melanoma remain unclear. The present study aimed to investigate the possible effects of miR-517a on oxidative stress (OS) in melanoma cells.

Methods

miR-517a expression in melanoma was determined using RT-qPCR. After treatment with different concentrations of H₂O₂, cell viability was determined in order to identify the most appropriate H₂O₂ concentration. Through loss and gain of function experiments, the interactions between miR-517a, the cyclin dependent kinase inhibitor 1C (CDKN1C) and the c-Jun NH2-terminal kinase (JNK) signaling pathway, as well as their roles in OS of melanoma cells were identified. Moreover, the expression of Cleaved Caspase-3, extent of ERK1/2 phosphorylation, Bax/Bcl-2 ratio, levels of T-AOC, ROS and MDA, and SOD activity were also tested. Finally, melanoma cell viability and apoptosis were detected.

Results

MiR-517a was upregulated, while CDKN1C was downregulated in melanoma tissues and cells. MiR-517a targets CDKN1C and consequently reduced its expression. Inhibition of miR-517a was shown to increase Cleaved Caspase-3 expression, Bax/Bcl-2 ratio, levels of ROS and MDA, as well as cell apoptosis but decrease extent of ERK1/2 phosphorylation, T-AOC levels, SOD activity, along with cell proliferation and mitochondrial membrane potential.

Conclusions

Overall, silencing miR-517a results in upregulated CDKN1C expression, and inhibited JNK signaling pathway activation, consequently promoting OS in melanoma cells.

Non-coding RNAs in Lung Cancer Chemoresistance

Background:

Lung cancer is the leading cause of cancer-associated death worldwide with limited treatment options. The major available treatment options are surgery, radiotherapy, chemotherapy and combinations of these treatments. In chemotherapy, tyrosine kinase inhibitors and taxol are the first lines of chemotherapeutics used for the treatment of lung cancer. Often drug resistance in the clinical settings hinders the efficiency of the treatment and intrigues the tumor relapse. Drug-resistance is triggered either by intrinsic factors or due to the prolonged cycles of chemotherapy as an acquired-resistance. There is an emerging role of non-coding RNAs (ncRNAs), including notorious microRNAs (miRNAs), proposed to be actively involved in the regulations of various tumor-suppressor genes and oncogenes.

Result:

The altered gene expression by miRNA is largely mediated either by the degradation or by interfering with the translation of targeted mRNA. Unlike miRNA, other type of ncRNAs, such as long non-coding RNAs (lncRNAs), can target the transcriptional activator or the repressor, RNA polymerase, and even DNA-duplex to regulate the gene expressions. Many studies have confirmed the crucial role of ncRNAs in lung adenocarcinoma progression and importantly, in the acquisition of chemoresistance. Recently, ncRNAs have become early biomarkers and therapeutic targets for lung cancer.

Conclusion:

Targeting ncRNAs could be an effective approach for the development of novel therapeutics against lung cancer and to overcome the chemoresistance.

miR-647 inhibits glioma cell proliferation, colony formation and invasion by regulating HOXA9

BACKGROUND

MicroRNA-647 (miR-647) has been reported to regulate tumor development, although its role in glioma remains unclear.

METHODS

miR-647 expression in glioma cells and normal cells was measured using a quantitative real-time polymerase chain reaction. The effects of miR-647 expression on glioma cell proliferation, cell apoptosis, colony formation and cell invasion were measured using a cell counting kit-8 assay, flow cytometry, a colony formation assay and a transwell invasion assay. Luciferase activity reporter and western blot assays were conducted to explore whether homeobox A9 (HOXA9) was a direct target of miR-647.

RESULTS

We found that miR-647 expression was downregulated in glioma cell lines compared to the normal cell line. Overexpression of miR-647 inhibits glioma cell proliferation, colony formation and cell invasion, although it promotes apoptosis in vitro. HOXA9 was validated a direct target of miR-647 and the overexpression of HOXA9 reversed the effects of miR-647 on glioma cell behavior.

CONCLUSIONS

The identification of the miR-647/HOXA9 axis will advance our understanding underlying glioma progression and provide novel therapeutic targets for glioma treatment.

Epigenetic control of tumor angiogenesis

The term "epigenetic" is used to refer to heritable alterations in chromatin that are not due to changes in DNA sequence. Different growth factors and vascular genes mediate the angiogenic process, which is regulated by epigenetic states of genes. The aim of this article is to analyze the role of epigenetic mechanisms in the control and regulation of tumor angiogenetic processes. The reversibility of epigenetic events in contrast to genetic aberrations makes them potentially suitable for therapeutic intervention. In this context, DNA methyltransferase (DNMT) and HDAC inhibitors indirectly-via the tumor cells-exhibit angiostatic effects in vivo, and inhibition of miRNAs can contribute to the development of novel anti-angiogenesis therapies.

MicroRNAs in ovarian cancer and recent advances in the development of microRNA-based biosensors

Ovarian cancer is the most aggressive of all gynaecological malignancies and is the leading cause of cancer-associated mortality worldwide.

RNA Nanotechnology-Mediated Cancer Immunotherapy

RNA molecules (e.g., siRNA, microRNA, and mRNA) have shown tremendous potential for immunomodulation and cancer immunotherapy. They can activate both innate and adaptive immune system responses by silencing or upregulating immune-relevant genes. In addition, mRNA-based vaccines have recently been actively pursued and tested in cancer patients, as a form of treatment. Meanwhile, various nanomaterials have been developed to enhance RNA delivery to the tumor and immune cells. In this review article, we summarize recent advances in the development of RNA-based therapeutics and their applications in cancer immunotherapy. We also highlight the variety of nanoparticle platforms that have been used for RNA delivery to elicit anti-tumor immune responses. Finally, we provide our perspectives of potential challenges and opportunities of RNA-based nanotherapeutics in clinical translation towards cancer immunotherapy.

miR-30b-3p Inhibits Proliferation and Invasion of Hepatocellular Carcinoma Cells via Suppressing PI3K/Akt Pathway

Background: The micro-RNA miR-30b-3p has been reported to play a crucial role in several cancers. However, the biological function of miR-30b-3p in hepatocellular carcinoma (HCC) is still unknown.

Methods: RT-qPCR was employed to determine the expression of miR-30b-3p in HCC tissues and cells. The MTT assay, colony formation assay, and cell migration and invasion assay were employed to evaluate the role of miR-30b-3p in HCC cells. A dual-luciferase reporter assay was employed to verify the target of miR-30b-3p. Western blotting was employed to determine the expression of key molecular signal transducers along TRIM27-PI3K/Akt axis.

Results: Expression of miR-30b-3p was markedly decreased in HCC tissues and cells and positively correlated with higher overall survival. Moreover, miR-30b-3p overexpression significantly repressed cell viability, proliferation, migration, and invasion of HCC cells in vitro. Notably, we demonstrated that miR-30b-3p directly bound to the 3′-untranslated region of tripartite motif containing 27 (TRIM27) mRNA by downregulating the expression of TRIM27, which was demonstrated to be negatively correlated with miR-30b-3p expression. TRIM27 was demonstrated to have an oncogenic role in HCC cells by enhancing cell viability, proliferation, migration, and invasion. Finally, the miR-30-3p-TRIM27-PI3K/Akt axis was shown to play a crucial role in HCC cells in vitro.

Conclusion: Our results indicated that miR-30-3p might act as a new biomarker for the future diagnosis and treatment HCC.

A fluorescence/colorimetric dual-mode sensing strategy for miRNA based on graphene oxide

MicroRNAs (miRNAs) are small non-coding RNAs, which are involved in RNA silencing and post-transcriptional regulation of gene expression. Numerous studies have determined the expression of certain miRNAs in specific tissues and cell types, and their aberrant expression is associated with a variety of serious diseases such as cancers, immune-related diseases, and many infectious diseases. This suggests that miRNAs may be attractive and promising non-invasive biomarkers of diseases. In this study, we established a graphene oxide (GO)-based fluorescence/colorimetric dual sensing platform for miRNA by using a newly designed probe. The probe was designed to form a hairpin-like configuration with a fluorescent dye-labeled long tail, possessing a guanine (G)-rich DNAzyme domain in the loop region and target binding domain over the stem region and tail. By introducing this new hairpin-like probe in a conventional GO-based fluorescence platform, we observed both the miRNA-responsive color change by direct observation and sensitive fluorescence increase even below the nanomolar levels in a single solution without an additional separation step.

Mechanisms of Disease Progression and Resistance to Tyrosine Kinase Inhibitor Therapy in Chronic Myeloid Leukemia: An Update

Chronic myeloid leukemia (CML) is characterized by the presence of the BCR-ABL1 fusion gene, which encodes a constitutive active tyrosine kinase considered to be the pathogenic driver capable of initiating and maintaining the disease. Despite the remarkable efficacy of tyrosine kinase inhibitors (TKIs) targeting BCR-ABL1, some patients may not respond (primary resistance) or may relapse after an initial response (secondary resistance). In a small proportion of cases, development of resistance is accompanied or shortly followed by progression from chronic to blastic phase (BP), characterized by a dismal prognosis. Evolution from CP into BP is a multifactorial and probably multistep phenomenon. Increase in BCR-ABL1 transcript levels is thought to promote the onset of secondary chromosomal or genetic defects, induce differentiation arrest, perturb RNA transcription, editing and translation that together with epigenetic and metabolic changes may ultimately lead to the expansion of highly proliferating, differentiation-arrested malignant cells. A multitude of studies over the past two decades have investigated the mechanisms underlying the closely intertwined phenomena of drug resistance and disease progression. Here, we provide an update on what is currently known on the mechanisms underlying progression and present the latest acquisitions on BCR-ABL1-independent resistance and leukemia stem cell persistence.

microRNAs Are Key Regulators in Chronic Lung Disease: Exploring the Vital Link between Disease Progression and Lung Cancer

microRNAs (miRNAs) bind to mRNAs and inhibit their expression through post-transcriptionally regulating gene expression. Here, we elaborate upon the concise summary of the role of miRNAs in carcinogenesis with specific attention to precursor respiratory pathogenesis caused by cigarette smoke modulation of these miRNAs. We review how miRNAs are implicated in cigarette-smoke-driven mechanisms, such as epithelial to mesenchymal transition, autophagy modulation, and lung ageing, which are important in the development of chronic obstructive pulmonary disease and potential progression to lung cancer. Extracellular vesicles are key to inter-cellular communication and sharing of miRNAs. A deeper understanding of the role of miRNAs in chronic respiratory disease and their use as clinical biomarkers has great potential. Therapeutic targeting of miRNAs may significantly benefit the prevention of cancer progression.

CLK3 Is A Direct Target Of miR-144 And Contributes To Aggressive Progression In Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer with high incidence. The underlying molecular mechanisms of HCC development have been intensively studied. CLK3 (CDC Like Kinase 3) is a nuclear dual-specificity kinase and regulates gene splicing. We investigated the expression profile and functional role of CLK3 in HCC.

Methods

Immunohistochemistry (IHC) and Western blot were performed to determine CLK3 expression in HCC tissues. Bioinformatics analysis using TCGA and GEO database was conducted to evaluate the relationship between CLK3 expression and HCC prognosis. Cell proliferation was assessed by CCK8, EdU and colony formation assays, while transwell and wound-healing assays were performed to investigate the cell migration and invasion in vitro. Xenograft nude mouse model was used to test the function of CLK3 on tumor growth in vivo. Luciferase reporter assay, Western blot and RT-qPCR were conducted to verify the miRNA that directly targeted CLK3.

Results

CLK3 was markedly upregulated in HCC tissues, and the expression levels of CLK3 were closely associated with TNM stages and HCC prognosis. Functional analysis indicated that knockdown of CLK3 could suppress HCC cell growth, invasion and migration in vitro, and inhibit tumor development in vivo. Moreover, CLK3 was demonstrated as a direct target of miR-144 and miR-144 expression was inversely correlated with CLK3 expression in HCC. Enforced overexpression of miR-144 markedly inhibited the CLK3 expression while overexpression of CLK3 partially reversed the inhibitory function of miR-144 on HCC cell growth and metastasis. Mechanistically, we found that miR-144 overexpression inhibited Wnt/β-catenin signaling and the inhibition could be partly abolished by overexpression of CLK3.

Conclusion

In summary, we demonstrate tumor suppressor miR-144 suppresses hepatocellular carcinoma development and metastasis via regulating CLK3 and Wnt/β-catenin signaling, indicating that miR-144/CLK3 could be used for HCC diagnosis and treatment.

Exploring specific prognostic biomarkers in triple-negative breast cancer

Lacking of both prognostic biomarkers and therapeutic targets, triple-negative breast cancer (TNBC) underscores pivotal needs to uncover novel biomarkers and viable therapies. MicroRNAs have broad biological functions in cancers and may serve as ideal biomarkers. In this study, by data mining of the Cancer Genome Atlas database, we screened out 4 differentially-expressed microRNAs (DEmiRNAs) between TNBC and normal samples: miR-135b-5p, miR-9-3p, miR-135b-3p and miR-455-5p. They were specially correlated with the prognosis of TNBC but not non-TNBC. The weighted correlation network analysis (WGCNA) for potential target genes of 3 good prognosis-related DEmiRNAs (miR-135b-5p, miR-9-3p, miR-135b-3p) identified 4 hub genes with highly positive correlation with TNBC subtype: FOXC1, BCL11A, FAM171A1 and RGMA. The targeting relationships between miR-9-3p and FOXC1/FAM171A1, miR-135b-3p and RGMA were validated by dual-luciferase reporter assays. Importantly, the regulatory functions of 4 DEmiRNAs and 3 verified target genes on cell proliferation and migration were explored in TNBC cell lines. In conclusion, we shed lights on these 4 DEmiRNAs (miR-135b-5p, miR-9-3p, miR-135b-3p, miR-455-5p) and 3 hub genes (FOXC1, FAM171A1, RGMA) as specific prognostic biomarkers and promising therapeutic targets for TNBC.

Circulating miRNAs as Biomarker in Cancer

Deregulation of microRNA expression has been shown to play an important role in human malignancies. The identification of circulating-free miRNAs in biofluids a decade ago led to great enthusiasm and motivation to develop non-invasive tests based on the expression of these small non-coding RNAs. Herein, we review the progress within the field of research for identifying circulating miRNA cancer biomarkers and discuss the advantages and challenges associated with this. We also discuss the methodological and analytical variables, which may influence the final miRNA quantification and the importance of standardizing pre-analytical, analytical, and post-analytical processes in order to enable a successful translation of the results from basic research into the clinics.

MicroRNA-7-5p induces cell growth inhibition, cell cycle arrest and apoptosis by targeting PAK2 in non-small cell lung cancer

MicroRNAs (miR) are known to be critical regulators in tumor progression. miR-7-5p was reported to be involved in several cancers, including glioblastoma, cervical cancer, and melanoma, but its prognostic value and biological function in non-small-cell lung cancer (NSCLC) remain unclear. In this study, using quantitative real-time PCR analysis, we found that miR-7-5p was significantly downregulated in NSCLC tissues and cell lines. Lower miR-7-5p expression was associated with tumor-node-metastasis stage and tumor size by chi-squared test. Deceased miR-7-5p expression was associated with a worse prognosis in patients with NSCLC using Kaplan-Meier survival analysis and multivariate Cox regression analysis. Experiments in NSCLC cell lines (A549 and H1299) demonstrated that upregulation of miR-7-5p significantly suppressed cell proliferation, but induced cell cycle G0/G1 phase arrest and apoptosis using Cell Counting Kit-8, colony formation, and flow cytometry analysis. Through loss-of-function assays, we further demonstrated that downregulation of miR-7-5p promoted cell proliferation and cell cycle G1/S transition, but decreased cell apoptosis in SPC-A1 cells. Furthermore, P21-activated kinase 2 (PAK2) was predicted and confirmed as a direct target gene of miR-7-5p in NSCLC cells by luciferase reporter assay. In addition, we found PAK2 overexpression could partially reverse the effects of miR-7-5p on cell proliferation, cell cycle distribution, and apoptosis. We thus concluded that lower expression of miR-7-5p was associated with poor prognosis and NSCLC progression by directly targeting PAK2.

MicroRNA 452 Regulates Cell Proliferation, Cell Migration, and Angiogenesis in Colorectal Cancer by Suppressing VEGFA Expression

The human microRNA 452 (MIR452) was identified as a colorectal cancer (CRC)-associated micro RNA (miRNA) by miRNA expression profiling of human CRC tissues versus normal colorectal tissues. It was significantly up-regulated in human CRC tissues. However, the functional mechanisms of MIR452 and its target genes in CRC remain unclear. We identified 27 putative MIR452 target genes, and found that the vascular endothelial growth factor A (VEGFA) was a direct target gene of MIR452. Both cellular and extracellular VEGFA levels were significantly downregulated in CRC cells upon their transfection with MIR452 or siVEGFA. VEGFA expression was frequently downregulated in human CRC tissues in comparison with that in their healthy counterparts. We showed that MIR452 regulated the expression of genes in the VEGFA-mediated signal transduction pathways vascular endothelial growth factor receptor 1 (VEGFR2)-mitogen-activated protein kinase (MAPK) and VEGFR2-SRC proto-oncogene non-receptor tyrosine kinase (SRC) in CRC cells. Immunohistological analyses of xenografted MIR452-overexpressing CRC cells in mice showed that MIR452 regulated cell proliferation and angiogenesis. Furthermore, aortic ring angiogenesis assay in rats clearly showed that the number of microvessels formed was significantly reduced by MIR452 transfection. Our findings suggest that MIR452 regulates cell proliferation, cell migration, and angiogenesis by suppressing VEGFA expression in early CRC progression; therefore, MIR452 may have therapeutic value in relation to human CRC.

Long non-coding RNA LOC554202 promotes acquired gefitinib resistance in non-small cell lung cancer through upregulating miR-31 expression

Non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutation inevitably have a relapse due to the occurrence of acquired resistance, resulting in treatment failure. However, little is known about the mechanisms of acquired resistance of NSCLC patients. Here, we elucidated the expression pattern of LOC554202 and miR-31, and their biological functions and mechanisms in NSCLC with acquired EGFR TKI resistance to gefitinib. In the present study, we observed that LOC554202 and miR-31 promoted proliferation and clonogenic growth of gefitinib-resistant NSCLC cells in vitro. LOC554202 upregulated miR-31 expression and they both reduced sensitivity of NSCLC cells to gefitinib. In a xenograft mice model, we found that knockdown of miR-31 significantly repressed gefitinib-resistant NSCLC cells growth in vivo. Furthermore, both LOC554202 and miR-31 levels were significantly increased in NSCLC patients acquiring resistance to gefitinib, and the expression of LOC554202 was positively correlated with the expression of miR-31. By luciferase reporter assays, we identified RAS P21 Protein Activator 1 (RASA1) and Hypoxia Inducible Factor 1 Subunit Alpha Inhibitor (FIH-1) as direct targets of miR-31 in NSCLC cells. Mechanistically, miR-31 directly repressed RASA1 and FIH-1 expression, and thus, at least partially activated the RAF-MEK-ERK and PI3K-AKT signaling pathways in NSCLC with acquired resistance to gefitinib. In conclusion, these data will help us develop potential therapeutic targets for the diagnosis and treatment of acquired EGFR TKI resistance in EGFR-mutant NSCLC.

MicroRNA in Pancreatic Cancer: From Biology to Therapeutic Potential

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

Circular RNA SMARCA5 inhibits the proliferation, migration, and invasion of non-small cell lung cancer by miR-19b-3p/HOXA9 axis

Background

Non-small cell lung cancer (NSCLC) is the main type of lung cancer, remaining a leading cause of cancer-related mortality around the world. Circular RNA SMARCA5 (circSMARCA5) is a novel circular RNA associated with the pathogenesis of several cancers. However, the role of circSMARCA5 in NSCLC remains unknown. In the present study, we aimed to evaluate the functions of circSMARCA5 in NSCLC and the underlying mechanism.

Methods

The expression pattern of circSMARCA5 was determined using qRT-PCR in NSCLC samples and cell lines. The correlation between miR-19b-3p and circSMARCA5 in NSCLC tissues was detected by qRT-PCR. Cell proliferation was examined utilizing CCK-8 assay. Cell migration and invasion was evaluated using Transwell assay. We used the bioinformatics software TargetScan and miRanda to predict circRNA-miRNA and miRNAi-mRNA interactions. Further, the regulatory role of circSMARCA5 in the malignant development of NSCLC in vivo was examined.

Results

The results showed that circSMARCA5 was down-regulated in NSCLC tissues as compared to the adjacent normal tissues. Overexpression of circSMARCA5 in NSCLC cell lines significantly inhibited the proliferation, migration, and invasion. Furthermore, circSMARCA5 exerted its tumor-suppressive activity through acting as a sponge for microRNA (miR)-19b-3p. Suppression of miR-19b-3p exhibited inhibitory effects on proliferation, migration, and invasion of NSCLC cell lines, which could be attributed to the regulation of homeobox A9 expression. Finally, overexpression of circSMARCA5 inhibited tumor growth in vivo.

Conclusion

Collectively, circSMARCA5 executed its inhibitory effects on NSCLC cell lines through miR-19b-3p/HOXA9 axis. The results indicated that circSMARCA5 might be a therapeutic target for the treatment of NSCLC.

MiR-29a function as tumor suppressor in cervical cancer by targeting SIRT1 and predict patient prognosis

INTRODUCTION

Cervical cancer is the second most frequently malignant tumors in females and metastasis is a challenge of the treatment of cervical cancer. MiR-29a is usually low expressed in several tumors and its functions in cervical cancer remain unclear.

PATIENTS AND METHODS

The quantitative real-time polymerase chain reaction was employed to assess the expression of miR-29a and the Sirtuin-1 (SIRT1). Cell metastatic ability was assessed using Transwell and Western blot assays. The dual-luciferase reporter assay was performed to verify that miR-29a targeted to the 3'-untranslated region (UTR) of SIRT1 mRNA.

RESULTS

MiR-29a was low expressed in cervical cancer and downregulation of miR-29a was associated with poor outcome. MiR-29a regulated the expression of SIRT1 by targeting to its 3'-UTR of mRNA in HeLa cells. SIRT1 was upregulated in cervical cancer tissues and cells in comparison with the non-tumor tissues and normal cells. Upregulation of SIRT1 predicted worse outcome of cervical cancer patients. MiR-29a was participated in the migration, invasion and epithelial-mesenchymal transition (EMT) in cervical cancer through directly targeting to the 3'-UTR of SIRT1 mRNA. SIRT1 reversed partial roles of miR-29a on metastasis in cervical cancer.

CONCLUSION

miR-29a suppressed migration, invasion and EMT by directly targeting to SIRT1 in cervical cancer. The newly identified miR-29a/SIRT1 axis provides novel insight into the pathogenesis of cervical cancer.

Identification of microRNAs modulated by DNA hypomethylating drugs in extranodal NK/T-cell lymphoma

To identify epigenetically silenced miRNAs and to investigate their influences on predictive target oncogenes in extranodal natural killer/T-cell lymphoma (NKTCL). Decitabine treatment was performed to evaluate methylated miRNAs in NKTCL cells. The relationship between a given miRNA and its target mRNA was validated using 24 tumor tissues. miR-379, miR-134, miR-20b, miR-376a, miR-654-3p, miR-143, miR-181c, miR-1225-5p, miR-1246, and miR-1275 were epigenetically silenced in SNK6 cells. miR-134, miR-376a, miR-143 and miR-181c significantly affected cellular viability. PDGFRα was regulated by miR-34a and miR-181c. miR-143, miR-20b and miR34a regulated STAT3 expression. miR-20b and miR-143 expression showed inverse correlations with STAT3 mRNA expression in NKTCL tissues. K-RAS was regulated by miR-181c. Downregulation of cell viability by salirasib treatment was identified. miRNAs were downregulated by DNA methylation, and several microRNAs affected the viability of NKTCL cells. miR-34a and miR-181c may be involved in the oncogenic progression of NKTCL through the regulation of PDGFRα, STAT3, and K-RAS.

MiR-1208 Increases the Sensitivity to Cisplatin by Targeting TBCK in Renal Cancer Cells

MicroRNAs (miRNAs) can be used to target a variety of human malignancies by targeting their oncogenes or tumor suppressor genes. Recent evidence has shown that miRNA-1208 (miR-1208) was rarely expressed in a variety of cancer cells, suggesting the possibility that miR-1208 functions as a tumor suppressor gene. Herein, ectopic expression of miR-1208 induced the accumulation of sub-G1 populations and the cleavage of procaspase-3 and PARP, which could be prevented by pre-treatment with the pan-caspase inhibitor, Z-VAD. In addition, miR-1208 increased the susceptibility to cisplatin and TRAIL in Caki-1 cells. Luciferase reporter assay results showed that miR-1208 negatively regulates TBC1 domain containing kinase (TBCK) expression by binding to the miR-1208 binding sites in the 3′-untranslated region of TBCK. In addition, miR-1208 specifically repressed TBCK expression at the transcriptional level. In contrast, inhibition of endogenous miR-1208 by anti-miRs resulted in an increase in TBCK expression. Downregulation of TBCK induced by TBCK-specific siRNAs increased susceptibility to cisplatin and TRAIL. These findings suggest that miR-1208 acts as a tumor suppressor and targets TBCK directly, thus possessing great potential for use in renal cancer therapy.