MicroRNA-34a inhibits the proliferation and metastasis of osteosarcoma cells both in vitro and in vivo. PLoS One. 2012;7:e33778. [PMID: 22457788 DOI: 10.1371/journal.pone.0033778]

The role of MiRNA-34 family in different signaling pathways and its therapeutic options

MiRNAs are short non-coding RNA molecules that have been shown to affect a vast number of genes at the post-transcriptional level, hence regulating several signaling pathways. Because the miRNA-34 family regulates a number of different signaling pathways, including those linked to cancer, the immune system, metabolism, cellular structure, and neurological disorders, it has garnered a great deal of attention from researchers. Members of the miRNA-34 family have been shown to inhibit tumors in a variety of cancer types. This family is also important for obesity, the cardiovascular system, and glycolysis. It's interesting to note that the miRNA-34 family is known to play a role in major depressive disorder, schizophrenia, Parkinson's disease (PD), adverse childhood experiences or trauma, regulation of stress responses, Alzheimer's disease (AD), and stress-related psychatric conditions. In this review, the expected targets of the miRNA-34 family are presented alongside the well-established targets identified by pathway analysis. Furthermore, the therapeutic potential of this miRNA family will be discussed.

Engineered bone marrow as a clinically relevant ex vivo model for primary bone cancer research and drug screening

Osteosarcoma (OS) is the most common primary malignant bone cancer in children and adolescents. While numerous other cancers now have promising therapeutic advances, treatment options for OS have remained unchanged since the advent of standard chemotherapeutics and offer less than a 25% 5-y survival rate for those with metastatic disease. This dearth of clinical progress underscores a lack of understanding of OS progression and necessitates the study of this disease in an innovative system. Here, we adapt a previously described engineered bone marrow (eBM) construct for use as a three-dimensional platform to study how microenvironmental and immune factors affect OS tumor progression. We form eBM by implanting acellular bone-forming materials in mice and explanting the cellularized constructs after 8 wk for study. We interrogate the influence of the anatomical implantation site on eBM tissue quality, test ex vivo stability under normoxic (5% O2) and standard (21% O2) culture conditions, culture OS cells within these constructs, and compare them to human OS samples. We show that eBM stably recapitulates the composition of native bone marrow. OS cells exhibit differential behavior dependent on metastatic potential when cultured in eBM, thus mimicking in vivo conditions. Furthermore, we highlight the clinical applicability of eBM as a drug-screening platform through doxorubicin treatment and show that eBM confers a protective effect on OS cells that parallel clinical responses. Combined, this work presents eBM as a cellular construct that mimics the complex bone marrow environment that is useful for mechanistic bone cancer research and drug screening.

Signal Pathways and microRNAs in Osteosarcoma Growth and the Dual Role of Mesenchymal Stem Cells in Oncogenesis

The major challenges in Osteosarcoma (OS) therapy are its heterogeneity and drug resistance. The development of new therapeutic approaches to overcome the major growth mechanisms of OS is urgently needed. The search for specific molecular targets and promising innovative approaches in OS therapy, including drug delivery methods, is an urgent problem. Modern regenerative medicine focuses on harnessing the potential of mesenchymal stem cells (MSCs) because they have low immunogenicity. MSCs are important cells that have received considerable attention in cancer research. Currently, new cell-based methods for using MSCs in medicine are being actively investigated and tested, especially as carriers for chemotherapeutics, nanoparticles, and photosensitizers. However, despite the inexhaustible regenerative potential and known anticancer properties of MSCs, they may trigger the development and progression of bone tumors. A better understanding of the complex cellular and molecular mechanisms of OS pathogenesis is essential to identify novel molecular effectors involved in oncogenesis. The current review focuses on signaling pathways and miRNAs involved in the development of OS and describes the role of MSCs in oncogenesis and their potential for antitumor cell-based therapy.

Deubiquitinating enzyme USP10 promotes osteosarcoma metastasis and epithelial-mesenchymal transition by stabilizing YAP1

BACKGROUND

Osteosarcoma (OS) is a fatal adolescent tumor, which is susceptible to remote metastases at an early stage, and its treatment remains a major challenge. ubiquitin-specific protease 10 (USP10) is primarily located in the cytoplasm and can therefore deubiquitinate various cytoplasmic proteins. However, the expression and mechanism of USP10 in OS remain ambiguous. The aim of this study was to explore how USP10 affects Yes-associated protein1 (YAP1) to influence the metastasis and epithelial-mesenchymal transition (EMT).

METHODS

Western blotting, qRT-PCR, and immunohistochemical (IHC) analyses were performed to evaluate USP10 and YAP1 levels. Using wound healing and transwell tests, the roles and molecular pathways of USP10 and YAP1 ability to migrate and invade of OS were investigated, and cell morphological alterations were examined using phalloidin staining.

RESULTS

Our results indicated that USP10, a new type of deubiquitinating protease, is increased in OS tissues and cells contrasted with adjacent healthy tissues. Overexpression of USP10 correlated with tumor size, distant metastasis, and TNM stage, and was an independent factor of poor prognosis in OS patients. Also, USP10 expression is closely connected with the incident of OS metastasis and tumor size. Functional assays revealed that USP10 knockdown suppressed cell migrating and invading ability and inhibited the EMT of OS cells in vivo and in vitro. In addition, we showed that USP10 knockdown decreased the levels of YAP1, which is an important positive regulator of migration and invasion in many cancers. We also found a significant positive correlation between USP10 and YAP1 levels, further demonstrating that USP10-induced migration and EMT are based on YAP1 in OS cells. In a mechanistic way, USP10 stabilizes the expression of YAP1 by mediating its deubiquitination in OS cells.

CONCLUSION

Together, this study showed that USP10 can directly interact with YAP1 to reduce ubiquitinated YAP1, thereby stabilizing its protein levels and affecting EMT and distant metastasis in OS cells.

A spotlight on the interplay of signaling pathways and the role of miRNAs in osteosarcoma pathogenesis and therapeutic resistance

Osteosarcoma (OS) is one of the most common bone cancers that constantly affects children, teenagers, and young adults. Numerous epigenetic elements, such as miRNAs, have been shown to influence OS features like progression, initiation, angiogenesis, and treatment resistance. The expression of numerous genes implicated in OS pathogenesis might be regulated by miRNAs. This effect is ascribed to miRNAs' roles in the invasion, angiogenesis, metastasis, proliferation, cell cycle, and apoptosis. Important OS-related mechanistic networks like the WNT/b-catenin signaling, PTEN/AKT/mTOR axis, and KRAS mutations are also affected by miRNAs. In addition to pathophysiology, miRNAs may influence how the OS reacts to therapies like radiotherapy and chemotherapy. With a focus on how miRNAs affect OS signaling pathways, this review seeks to show how miRNAs and OS are related.

Canine osteosarcoma in comparative oncology: Molecular mechanisms through to treatment discovery

Cancer is a leading cause of non-communicable morbidity and mortality throughout the world, similarly, in dogs, the most frequent cause of mortality is tumors. Some types of cancer, including osteosarcoma (OSA), occur at much higher rates in dogs than people. Dogs therefore not only require treatment themselves but can also act as an effective parallel patient population for the human disease equivalent. It should be noted that although there are many similarities between canine and human OSA, there are also key differences and it is important to research and highlight these features. Despite progress using chorioallantoic membrane models, 2D and 3D in vitro models, and rodent OSA models, many more insights into the molecular and cellular mechanisms, drug development, and treatment are being discovered in a variety of canine OSA patient populations.

MicroRNA34a is associated with chemotherapy resistance, metastasis, recurrence, survival, and prognosis in patient with osteosarcoma

BACKGROUND

Osteosarcoma (OS) is the primary malignant bone tumor that most commonly affects children, adolescents, and young adults. MicroRNA-34a (miR-34a) is involved in tumor metastasis and may be a prognostic marker for patients with cancer. The aim of the present study was to explore the role of miR-34a in patients with OS. The underlying associations between miR-34a expressions and metastasis, recurrence as well as and prognosis were comprehensively analyzed in OS patients.

METHODS

Reverse transcriptase quantitative PCR (RT-qPCR) was used to investigate serum level of miR-34a between clinical OS patients (n = 162) and age-matched healthy controls (n = 162). Expression of miR-34a in OS tissues and adjacent tissues was analyzed using RT-qPCR. RT-qPCR was used to compare the serum level of miR-34a in patients with OS before and after chemotherapy. Multivariate Cox-regression analysis was used to analyze the association between serum level of miR-34a and chemotherapy resistance, overall survival, as well as recurrence and prognosis of OS patients. Five-year recurrence and survival were estimated using Kaplan-Meier curves.

RESULTS

Serum level of miR-34a was downregulated in OS patients (n = 86) compared to age-matched healthy controls (n = 86). Expression of miR-34a was downregulated in OS tissue compared to adjacent tissues in clinical patients. The expression of serum miR-34a before and after chemotherapy was positively correlated with the expression of miR-34a in the corresponding tissues. Expression of miR-34a was higher in the group where chemotherapy was effective than that patient where chemotherapy was ineffective. Expression of miR-34a was negatively associated with chemotherapy resistance of OS patients. High serum levels of miR-34a were associated with longer overall survival in OS patients and lower metastasis. Multivariate Cox-regression analysis identified miR-34a serum level with potential prognostic significance.

CONCLUSION

The expression level of serum miR-34a in patients with OS is closely related to the chemotherapy resistance, metastasis, recurrence, and survival of osteosarcoma, which can be used as one of the potential biomarkers and prognosis for the treatment of OS patients. Therefore, miR-34a may be a potential molecular for prediction of the efficacy of chemotherapy and prognosis in OS patients.

Lysophosphatidic Acid Signaling and microRNAs: New Roles in Various Cancers

A wide range of microRNAs (miRNAs) are coded for in the human genome and contribute to the regulation of gene expression. MiRNAs are able to degrade mRNAs and/or prevent the RNA transcript from being translated through complementary binding of the miRNA seed region (nucleotide 2-8) to the 3'-untranslated regions of many mRNAs. Although miRNAs are involved in almost all processes of normal human cells, they are also involved in the abnormal functions of cancer cells. MiRNAs can play dual regulatory roles in cancer, acting either as tumor suppressors or as tumor promoters, depending on the target, tumor type, and stage. In the current review, we discuss the present status of miRNA modulation in the setting of lysophosphatidic acid (LPA) signaling. LPA is produced from lysophosphatidylcholine by the enzyme autotaxin and signals via a range of G protein-coupled receptors to affect cellular processes, which ultimately causes changes in cell morphology, survival, proliferation, differentiation, migration, and adhesion. Several studies have identified miRNAs that are over-expressed in response to stimulation by LPA, but their functional roles have not yet been fully clarified. Since RNA-based treatments hold tremendous promise in the area of personalized medicne, many efforts have been made to bring miRNAs into clinical trials, and this field is evolving at an increasing pace.

Mir-34a: a regulatory hub with versatile functions that controls osteosarcoma networks

Osteosarcoma (OS) is one of the most prevalent and highly aggressive bone malignancies. The treatment strategies of OS is under standard regimens, including surgical resection, chemotherapy, and other adjuvant therapy. However, the 5-year survival rate is still unsatisfactory. Previous studies have demonstrated that the expression of miR-34a decreases in osteosarcoma, which is involved in regulating numerous genes directly or indirectly at the post-transcriptional level and other pathways. Thus, miR-34a plays an important role in mediating OS cell proliferation, differentiation, migration, and apoptosis, and might be a pivotal biomarker for OS with diagnostic and therapeutic potentials. In this review, we aim to summarize the relationship between miR-34a and OS, with an emphasis on the specific mechanisms in OS development referring to miR-34a. Moreover, the potential role of miR-34a as a diagnostic, prognostic, and therapeutic candidate for OS would be presented in detail. However, the molecular mechanisms related to miR-34a and OS remain elusive, and more investigations are needed to reach a comprehensive understanding.

Deciphering the role of miRNA in reprogramming plant responses to drought stress

Drought is the most prevalent environmental stress that affects plants' growth, development, and crop productivity. However, plants have evolved adaptive mechanisms to respond to the harmful effects of drought. They reprogram their: transcriptome, proteome, and metabolome that alter their cellular and physiological processes and establish cellular homeostasis. One of the crucial regulatory processes that govern this reprogramming is post-transcriptional regulation by microRNAs (miRNAs). miRNAs are small non-coding RNAs, involved in the downregulation of the target mRNA via translation inhibition/mRNA degradation/miRNA-mediated mRNA decay/ribosome drop off/DNA methylation. Many drought-inducible miRNAs have been identified and characterized in plants. Their main targets are regulatory genes that influence growth, development, osmotic stress tolerance, antioxidant defense, phytohormone-mediated signaling, and delayed senescence during drought stress. Overexpression of drought-responsive miRNAs (Osa-miR535, miR160, miR408, Osa-miR393, Osa-miR319, and Gma-miR394) in certain plants has led to tolerance against drought stress indicating their vital role in stress mitigation. Similarly, knock down (miR166/miR398c) or deletion (miR169 and miR827) of miRNAs has also resulted in tolerance to drought stress. Likewise, engineered Arabidopsis plants with miR165, miR166 using short tandem target mimic strategy, exhibited drought tolerance. Since miRNAs regulate the expression of an array of drought-responsive genes, they can act as prospective targets for genetic manipulations to enhance drought tolerance in crops and achieve sustainable agriculture. Further investigations toward functional characterization of diverse miRNAs, and understanding stress-responses regulated by these miRNAs and their utilization in biotechnological applications is highly recommended.

Regular Intake of Green Tea Polyphenols Suppresses the Development of Nonmelanoma Skin Cancer through miR-29-Mediated Epigenetic Modifications

Previously, we and others have shown that the regular intake of green tea polyphenols (GTPs) reduces ultraviolet B (UVB) radiation-induced skin cancer by targeting multiple signaling pathways, including DNA damage, DNA repair, immunosuppression, and inflammation. Here, we determine the effect of GTPs on UVB-induced epigenetic changes, emphasizing DNA hypermethylation in UV-exposed skin and tumors and their association with miR-29, a key regulator of DNA methyltransferases (DNMTs). Skin cancer was induced in SKH-1 hairless mice following repeated exposures of UVB radiation (180 mJ/cm², three times/week, 24 weeks) with or without GTPs supplementation (0.2%) in drinking water. Regular intake of GTPs inhibited tumor growth by hindering the cascade of DNA hypermethylation events. GTPs supplementation significantly blocked UVB-induced DNA hypermethylation in the skin (up to 35%; p < 0.0001) and in tumors (up to 50%; p < 0.0001). Experimental results showed that the levels of DNA hypermethylation were higher in GTPs-treated mice than in the control group. The expressions of miR-29a, miR-29b, and miR-29c were markedly decreased in UV-induced skin tumors, and GTPs administration blocked UVB-induced miR-29s depletion. Furthermore, these observations were verified using the in vitro approach in human skin cancer cells (A431) followed by treatment with GTPs or mimics of miR-29c. Increased levels of miR-29 were observed in GTPs-treated A431 cells, resulting in increased TET activity and decreased DNA hypermethylation. In conclusion, UVB-mediated miR-29 depletion promotes DNA hypermethylation and leads to enhanced tumor growth by silencing tumor suppressors. Regular intake of GTPs rescued UVB-induced miR-29 depletion and prevented tumor growth by maintaining reduced DNA hypermethylation and activating tumor suppressors. Our observations suggest that miR-based strategies and regular consumption of GTPs could minimize the risk of UVB-induced skin cancers and contribute to better management of NMSCs.

The prominent role of miR-942 in carcinogenesis of tumors

As a family of short noncoding RNAs, MicroRNAs have been identified as possible biomarkers for cancer discovery and assist in therapy control due to their epigenetic involvement in gene expression and other cellular biological processes. In the present review, the evidence for reaching the clinical effect and the molecular mechanism of miR-942 in various kinds of cancer is amassed. Dysregulation of miR-942 amounts in different kinds of malignancies, as bladder cancer, esophageal squamous cell carcinoma, breast cancer, cervical cancer, gastric cancer, colorectal cancer, Kaposi's sarcoma, melanoma, Hepatocellular carcinoma, nonsmall-cell lung cancer, oral squamous cell carcinoma, osteosarcoma, ovarian cancer, pancreatic ductal adenocarcinoma, renal cell carcinoma, and prostate cancer has stated a considerable increase or decrease in its level indicating its function as oncogene or tumor suppressor. MiR-942 is included in cell proliferation, migration, and invasion through cell cycle pathways, including pathways of transforming growth factor-beta signaling pathways, Wnt pathway, JAK/STAT pathway, PI3K/AKT pathway, apoptosis pathway, hippo signaling pathway, lectin pathway, interferon-gamma signaling, signaling by G-protein coupled receptor, developmental genes, nuclear factor-kappa B pathway, Mesodermal commitment pathway, and T-cell receptor signaling in cancer. An important biomarker, MiR-942 is a potential candidate for prediction in several cancers. The present investigation introduced miR-942 as a prognostic marker for early discovery of tumor progression, metastasis, and development.

The hepatocyte growth factor/mesenchymal epithelial transition factor axis in high-risk pediatric solid tumors and the anti-tumor activity of targeted therapeutic agents

Clinical trials completed in the last two decades have contributed significantly to the improved overall survival of children with cancer. In spite of these advancements, disease relapse still remains a significant cause of death in this patient population. Often, increasing the intensity of current protocols is not feasible because of cumulative toxicity and development of drug resistance. Therefore, the identification and clinical validation of novel targets in high-risk and refractory childhood malignancies are essential to develop effective new generation treatment protocols. A number of recent studies have shown that the hepatocyte growth factor (HGF) and its receptor Mesenchymal epithelial transition factor (c-MET) influence the growth, survival, angiogenesis, and metastasis of cancer cells. Therefore, the c-MET receptor tyrosine kinase and HGF have been identified as potential targets for cancer therapeutics and recent years have seen a race to synthesize molecules to block their expression and function. In this review we aim to summarize the literature that explores the potential and biological rationale for targeting the HGF/c-MET pathway in common and high-risk pediatric solid tumors. We also discuss selected recent and ongoing clinical trials with these agents in relapsed pediatric tumors that may provide applicable future treatments for these patients.

Roles of MET in human cancer

The MET proto-oncogene was first identified in osteosarcoma cells exposed to carcinogens. Although expressed in many normal cells, MET is overexpressed in many human cancers. MET is involved in the initiation and development of various human cancers and mediates proliferation, migration and invasion. Accordingly, MET has been successfully used as a biomarker for diagnosis and prognosis, survival, post-operative recurrence, risk assessment and pathologic grading, as well as a therapeutic target. In addition, recent work indicates that inhibition of MET expression and function has potential clinical benefit. This review summarizes the role, mechanism, and clinical significance of MET in the formation and development of human cancer.

Combination therapy with miR34a and doxorubicin synergistically inhibits Dox-resistant breast cancer progression via down-regulation of Snail through suppressing Notch/NF-κB and RAS/RAF/MEK/ERK signaling pathway

Resistance to breast cancer (BCa) chemotherapy severely hampers the patient's prognosis. MicroRNAs provide a potential therapeutic prospect for BCa. In this study, the reversal function of microRNA34a (miR34a) on doxorubicin (Dox) resistance of BCa and the possible mechanism was investigated. We found that the relative level of miR34a was significantly decreased in Dox-resistant breast cancer cell MCF-7 (MCF-7/A) compared with Dox-sensitive MCF-7 cells. Transfection with miR34a significantly suppressed the invasion, migration, adhesion of MCF-7/A cells without inhibiting their growth obviously. The combination of miR34a and Dox could significantly inhibit the proliferation, migration, invasion and induce the apoptosis of MCF-7/A cells. The synergistic effect of this combination on resistant MCF-7/A cells has no obvious relation with the expressions of classical drug-resistant proteins P-GP, MRP and GST-π, while closely related with the down-regulation on TOP2A and BCRP. Moreover, we found both protein and mRNA expression of Snail were significantly up-regulated in MCF-7/A cells in comparison with MCF-7 cells. Transfection with small interfering RNA (siRNA) of Snail could inhibit the invasion, migration and adhesion of drug-resistant MCF-7/A cells, while high-expression of Snail could remarkably promote the invasion, migration and adhesion of MCF-7 cells, which might be related with regulation of N-cadherin and E-cadherin. Transfection with miR34a in MCF-7/A cells induced a decrease of Snail expression. The potential binding sites of miR34a with 3' UTR of Snail were predicted by miRDB target prediction software, which was confirmed by luciferase reporter gene method. Results showed that the relative activity of luciferase was reduced in MCF-7/A cells after co-transfection of miR34a and wild type (wt)-Snail, while did not change by co-transfection with miR34a and 3' UTR mutant type (mut) Snail. Combination of miR34a and Dox induced a stronger decrease of Snail in MCF-7/A cells in comparison to miR34a or Dox treatment alone. What' more, for the first time, we also found miR34a combined with Dox could obviously inhibit the expression of Snail through suppressing Notch/NF-κB and RAS/RAF/MEK/ERK pathway in MCF-7/A cells. In vivo study indicated that combination of miR34a and Dox significantly slowed down tumor growth in MCF-7/A nude mouse xenograft model compared with Dox alone, which was manifested by the down-regulation of Snail and pro-apoptosis effect in tumor xenografts. These results together underline the relevance of miR34a-driven regulation of Snail in drug resistance and co-administration of miR34a and Dox may produce an effective therapy outcome in the future in clinic.

Ligand-mediated delivery of RNAi-based therapeutics for the treatment of oncological diseases

RNA interference (RNAi)-based therapeutics (miRNAs, siRNAs) have great potential for treating various human diseases through their ability to downregulate proteins associated with disease progression. However, the development of RNAi-based therapeutics is limited by lack of safe and specific delivery strategies. A great effort has been made to overcome some of these challenges resulting in development of N-acetylgalactosamine (GalNAc) ligands that are being used for delivery of siRNAs for the treatment of diseases that affect the liver. The successes achieved using GalNAc-siRNAs have paved the way for developing RNAi-based delivery strategies that can target extrahepatic diseases including cancer. This includes targeting survival signals directly in the cancer cells and indirectly through targeting cancer-associated immunosuppressive cells. To achieve targeting specificity, RNAi molecules are being directly conjugated to a targeting ligand or being packaged into a delivery vehicle engineered to overexpress a targeting ligand on its surface. In both cases, the ligand binds to a cell surface receptor that is highly upregulated by the target cells, while not expressed, or expressed at low levels on normal cells. In this review, we summarize the most recent RNAi delivery strategies, including extracellular vesicles, that use a ligand-mediated approach for targeting various oncological diseases.

The outstanding role of miR-132-3p in carcinogenesis of solid tumors

MicroRNAs are a group of short non-coding RNAs (miRNAs), which are epigenetically involved in gene expression and other cellular biological processes and can be considered as potential biomarkers for cancer detection and support for treatment management. This review aims to amass the evidence to reach the molecular mechanism and clinical significance of miR-132 in different types of cancer. Dysregulation of miR-132 level in various types of malignancies, including hepatocellular carcinoma, breast cancer, colorectal cancer, gastric cancer, lung cancer, prostate cancer, osteosarcoma, pancreatic cancer, and ovarian cancer have reported, significantly decrease in its level, which can be indicated to its function as a tumor suppressor. miR-132 is involved in cell proliferation, migration, and invasion through cell cycle pathways, such as PI3K, TGFβ or hippo signaling pathways, or on oncogenes such as Ras, AKT, mTOR, glycolysis. miR-132 could be potentially a candidate as a valuable biomarker for prognosis in various cancers. Through this study, we proposed that miR-132 can potentially be a candidate as a prognostic marker for early detection of tumor development, progression, as well as metastasis.

The comprehensive landscape of miR-34a in cancer research

MicroRNA-34 (miR-34) plays central roles in human diseases, especially cancers. Inactivation of miR-34 is detected in cancer cell lines and tumor tissues versus normal controls, implying its potential tumor-suppressive effect. Clinically, miR-34 has been identified as promising prognostic indicators for various cancers. In fact, members of the miR-34 family, especially miR-34a, have been convincingly proved to affect almost the whole cancer progression process. Here, a total of 512 (miR-34a, 10/21), 85 (miR-34b, 10/16), and 114 (miR-34c, 10/14) putative targets of miR-34a/b/c are predicted by at least ten miRNA databases, respectively. These targets are further analyzed in gene ontology (GO), KEGG pathway, and the Reactome pathway dataset. The results suggest their involvement in the regulation of signal transduction, macromolecule metabolism, and protein modification. Also, the targets are implicated in critical signaling pathways, such as MAPK, Notch, Wnt, PI3K/AKT, p53, and Ras, as well as apoptosis, cell cycle, and EMT-related pathways. Moreover, the upstream regulators of miR-34a, mainly including transcription factors (TFs), lncRNAs, and DNA methylation, will be summarized. Meanwhile, the potential TF upstream of miR-34a/b/c will be predicted by PROMO, JASPAR, Animal TFDB 3.0, and GeneCard databases. Notably, miR-34a is an attractive target for certain cancers. In fact, miR-34a-based systemic delivery combined with chemotherapy or radiotherapy can more effectively control tumor progression. Collectively, this review will provide a panorama for miR-34a in cancer research.

MiRNAs in Canine and Human Osteosarcoma: A Highlight Review on Comparative Biomolecular Aspects

Osteosarcoma (OS) is the most frequent primary malignant tumor of bone in humans and animals. Comparative oncology is a field of study that examines the cancer risk and tumor progression across the species. The canine model is ideally suited for translational cancer research. The biological and clinical characteristics of human and canine OS are common to hypothesize as that several living and environmental common conditions shared between the two species can influence some etiopathogenetic mechanisms, for which the canine species represents an important model of comparison with the human species. In the canine and human species, osteosarcoma is the tumor of bone with the highest frequency, with a value of about 80–85% (in respect to all other bone tumors), a high degree of invasiveness, and a high rate of metastasis and malignancy. Humans and dogs have many genetic and biomolecular similarities such as alterations in the expression of p53 and in some types of microRNAs that our working group has already described previously in several separate works. In this paper, we report and collect new comparative biomolecular features of osteosarcoma in dogs and humans, which may represent an innovative update on the biomolecular profile of this tumor.

LINC01410 accelerated the invasion and proliferation of osteosarcoma by sponging miR-3128

Increasing evidence has shown that lncRNAs are closely correlated with cell apoptosis, autophagy and progression. However, the role of LINC01410 in osteosarcoma has not been verified. We determined that LINC01410 was overexpressed in osteosarcoma specimens and cell lines. The expression of LINC01410 was upregulated in 22 osteosarcoma patients (22/30, 73%) compared to control normal samples. Ectopic expression of LINC01410 promoted the osteosarcoma cell cycle, proliferation and invasion. Overexpression of LINC01410 induced N-cadherin and Vimentin expression and inhibited E-cadherin expression in osteosarcoma cells. LINC01410 acted as a sponge for miR-3128. The results showed that miR-3128 overexpression decreased the luciferase activity of WT-LINC01410 but not mut-LINC01410 in MG-63 cells. Upregulation of LINC01410 expression suppressed miR-3128 expression in MG-63 cells. Moreover, LINC01410 overexpression increased osteosarcoma cell invasion and growth by modulating miR-3128. These data indicated that LINC01410 acted as an oncogene in osteosarcomagenesis and might be a potential new strategy for osteosarcoma treatment.

Notch-1 promotes the malignant progression of osteosarcoma through the activation of cell division cycle 20

The molecular mechanism of osteosarcoma (OS) pathogenesis is poorly understood. The Notch signaling pathway has been shown to be critically involved in tumorigenesis, including OS. Therefore, we explored the molecular mechanism by which the Notch-1 signaling pathway is involved in OS progression. Several approaches were carried out to determine the biological function of Notch-1 in OS cells. The MTT results revealed that Notch-1 overexpression increased the viability of OS cells, whereas Notch-1 downregulation reduced cell viability. Consistently, modulation of Notch-1 regulated apoptosis and the migratory and invasive abilities of OS cells. Mechanistic studies showed that Notch-1 overexpression augmented cell division cycle 20 (Cdc20) expression in OS cells. Moreover, overexpression of Cdc20 alleviated the inhibitory effects of Notch-1 downregulation on the viability, migration and invasion of OS cells. Our study offers a promising OS treatment strategy by inhibiting Notch-1.

PRRX1 promotes malignant properties in human osteosarcoma

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PRRX1 is a poor-prognosis marker of human osteosarcoma.

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PRRX1 promotes proliferation, invasion, and drug resistance in human osteosarcoma.

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Forskolin was identified using RNA expression signatures of PRRX1 knockdown.

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Forskolin decreased proliferation and migration in human osteosarcoma.

Paired related homeobox 1 (PRRX1) is a marker of limb bud mesenchymal cells, and deficiency of p53 or Rb in Prrx1-positive cells induces osteosarcoma in several mouse models. However, the regulatory roles of PRRX1 in human osteosarcoma have not been defined. In this study, we performed PRRX1 immunostaining on 35 human osteosarcoma specimens to assess the correlation between PRRX1 level and overall survival. In patients with osteosarcoma, the expression level of PRRX1 positively correlated with poor prognosis or the ratio of lung metastasis. Additionally, we found PRRX1 expression on in 143B cells, a human osteosarcoma line with a high metastatic capacity. Downregulation of PRRX1 not only suppressed proliferation and invasion but also increased the sensitivity to cisplatin and doxorubicin. When 143B cells were subcutaneously transplanted into nude mice, PRRX1 knockdown decreased tumor sizes and rates of lung metastasis. Interestingly, forskolin, a chemical compound identified by Connectivity Map analysis using RNA expression signatures during PRRX1 knockdown, decreased tumor proliferation and cell migration to the same degree as PRRX1 knockdown. These results demonstrate that PRRX1 promotes tumor malignancy in human osteosarcoma.

Molecular Biology of Osteosarcoma

Osteosarcoma (OS) is the most frequent primary bone cancer in children and adolescents and the third most frequent in adults. Many inherited germline mutations are responsible for syndromes that predispose to osteosarcomas including Li Fraumeni syndrome, retinoblastoma syndrome, Werner syndrome, Bloom syndrome or Diamond-Blackfan anemia. TP53 is the most frequently altered gene in osteosarcoma. Among other genes mutated in more than 10% of OS cases, c-Myc plays a role in OS development and promotes cell invasion by activating MEK-ERK pathways. Several genomic studies showed frequent alterations in the RB gene in pediatric OS patients. Osteosarcoma driver mutations have been reported in NOTCH1, FOS, NF2, WIF1, BRCA2, APC, PTCH1 and PRKAR1A genes. Some miRNAs such as miR-21, -34a, -143, -148a, -195a, -199a-3p and -382 regulate the pathogenic activity of MAPK and PI3K/Akt-signaling pathways in osteosarcoma. CD133+ osteosarcoma cells have been shown to exhibit stem-like gene expression and can be tumor-initiating cells and play a role in metastasis and development of drug resistance. Although currently osteosarcoma treatment is based on adriamycin chemoregimens and surgery, there are several potential targeted therapies in development. First of all, activity and safety of cabozantinib in osteosarcoma were studied, as well as sorafenib and pazopanib. Finally, novel bifunctional molecules, of potential imaging and osteosarcoma targeting applications may be used in the future.

RPmirDIP: Reciprocal Perspective improves miRNA targeting prediction

MicroRNAs (miRNAs) are short, non-coding RNAs that interact with messenger RNA (mRNA) to accomplish critical cellular activities such as the regulation of gene expression. Several machine learning methods have been developed to improve classification accuracy and reduce validation costs by predicting which miRNA will target which gene. Application of these predictors to large numbers of unique miRNA-gene pairs has resulted in datasets comprising tens of millions of scored interactions; the largest among these is mirDIP. We here demonstrate that miRNA target prediction can be significantly improved ([Formula: see text]) through the application of the Reciprocal Perspective (RP) method, a cascaded, semi-supervised machine learning method originally developed for protein-protein interaction prediction. The RP method, aptly named RPmirDIP, augments the original mirDIP prediction scores by leveraging local thresholds from the two complimentary views available to each miRNA-gene pair, rather than apply a traditional global decision threshold. Application of this novel RPmirDIP predictor promises to help identify new, unexpected miRNA-gene interactions. A dataset of RPmirDIP-scored interactions are made available to the scientific community at cu-bic.ca/RPmirDIP and https://doi.org/10.5683/SP2/LD8JKJ.

MicroRNA-34a inhibits cell invasion and epithelial-mesenchymal transition via targeting AXL/PI3K/AKT/Snail signaling in nasopharyngeal carcinoma

BACKGROUND

MicroRNA-34a (miR-34a) has been reported to inhibit TGF-β (transforming growth factor-β)-induced epithelial-mesenchymal transition (EMT) in nasopharyngeal carcinoma (NPC). However, the underlying mechanism remain unclear. Using the bioinformatics, we found that the AXL receptor tyrosine kinase (AXL) is a predicted target of miR-34a.

OBJECTIVE

we aimed to reveal the relationship between miR-34a and AXL, and investigate the effect and mechanism of miR-34a in NPC progression.

METHODS

The expression patterns of miR-34a and AXL in 30 paired NPC tissues and the adjacent tissues were examined by quantitative real time PCR (qRT-PCR). The target relationship between miR-34a and AXL was evaluated by the luciferase gene reporter assay. Cell migration and invasion were assessed by wound healing and transwell chamber assays, respectively.

RESULTS

miR-34a level was dramatically decreased in the NPC tissues compared to the adjacent tissues, while AXL expression was increased. Overexpression of miR-34a significantly reduced the luciferase activity of the luciferase vector of AXL (pGL3-AXL-WT), whereas this effect was abrogated when binding sites between miR-34a and AXL were mutated. In addition, ectopic expression of miR-34a dramatically inhibited Sune-1 cell migration and invasion abilities, decreased the levels of N-cadherin and Vimentin and increased E-cadherin and γ-catenin expressions, as well as induced significant reductions in the expressions of p-AKT and Snail. However, these effects were attenuated when the cells were treated with recombinant human AXL protein.

CONCLUSIONS

Our results demonstrate that miR-34a/AXL can inhibit NPC cell migration, invasion and EMT through inhibition of AKT/Snail signaling.

MicroRNAs signatures, bioinformatics analysis of miRNAs, miRNA mimics and antagonists, and miRNA therapeutics in osteosarcoma

MicroRNAs (miRNAs) involved in key signaling pathways and aggressive phenotypes of osteosarcoma (OS) was discussed, including PI3K/AKT/MTOR, MTOR AND RAF-1 signaling, tumor suppressor P53- linked miRNAs, NOTCH- related miRNAs, miRNA -15/16 cluster, apoptosis related miRNAs, invasion-metastasis-related miRNAs, and 14Q32-associated miRNAs cluster. Herrin, we discussed insights into the targeted therapies including miRNAs (i.e., tumor-suppressive miRNAs and oncomiRNAs). Using bioinformatics tools, the interaction network of all OS-associated miRNAs and their targets was also depicted.

MicroRNAs and Long Non-coding RNAs in c-Met-Regulated Cancers

MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are components of many signaling pathways associated with tumor aggressiveness and cancer metastasis. Some lncRNAs are classified as competitive endogenous RNAs (ceRNAs) that bind to specific miRNAs to prevent interaction with target mRNAs. Studies have shown that the hepatocyte growth factor/mesenchymal-epithelial transition factor (HGF/c-Met) pathway is involved in physiological and pathological processes such as cell growth, angiogenesis, and embryogenesis. Overexpression of c-Met can lead to sustained activation of downstream signals, resulting in carcinogenesis, metastasis, and resistance to targeted therapies. In this review, we evaluated the effects of anti-oncogenic and oncogenic non-coding RNAs (ncRNAs) on c-Met, and the interactions among lncRNAs, miRNAs, and c-Met in cancer using clinical and tissue chromatin immunoprecipition (ChIP) analysis data. We summarized current knowledge of the mechanisms and effects of the lncRNAs/miR-34a/c-Met axis in various tumor types, and evaluated the potential therapeutic value of lncRNAs and/or miRNAs targeted to c-Met on drug-resistance. Furthermore, we discussed the functions of lncRNAs and miRNAs in c-Met-related carcinogenesis and potential therapeutic strategies.

A comprehensive analysis for associations between multiple microRNAs and prognosis of osteosarcoma patients

Background

Osteosarcoma (OS) is the most common malignant primary bone tumor occurring in children and young adults, which occupies the second important cause of tumor-associated deaths among children and young adults. Recent studies have demonstrated that many microRNAs (miRNAs) have abnormal expression in OS, and can function as prognostic factors of OS patients. However, no previous studies have comprehensively analyzed the relationship between multiple miRNAs and prognosis of OS patients.

Methods

A total of 63 OS patients were retrospectively enrolled. The clinical characteristics were collected, and the expression levels of miRNA-21, miRNA-30c, miRNA-34a, miRNA-101, miRNA-133a, miRNA-214, miRNA-218, miRNA-433 and miRNA-539 in tumor tissues were measured through quantitative real-time polymerasechain reaction. Kaplan–Meier analysis was used to perform univariate survival analysis, and Cox regression model was used to perform multivariate survival analysis which included the variables with P < 0.1 in univariate survival analysis.

Results

The cumulative survival for 1, 2 and 5 years was 90.48%, 68.25% and 38.10%, respectively, and mean survival time was (45.39 ± 3.60) months (95% CI [38.34–52.45]). Kaplan–Meier analysis demonstrated that TNM stage, metastasis or recurrence, miRNA-21, miRNA-214, miRNA-34a, miRNA-133a and miRNA-539 were correlated with cum survival, but gender, age, tumor diameter, differentiation, miRNA-30c, miRNA-433, miRNA-101 and miRNA-218 were not. Multivariate survival analysis demonstrated that miRNA-21 (hazard ratio (HR): 3.457, 95% CI [2.165–11.518]), miRNA (HR: 3.138, 95% CI [2.014–10.259]), miRNA-34a (HR: 0.452, 95% CI [0.202–0.915]), miRNA-133a (HR: 0.307, 95% CI [0.113–0.874]) and miRNA-539 (HR: 0.358, 95% CI [0.155–0.896]) were independent prognostic markers of OS patients after adjusting for TNM stage (HR: 2.893, 95% CI [1.496–8.125]), metastasis or recurrence (HR: 3.628, 95% CI [2.217–12.316]) and miRNA-30c (HR: 0.689, 95% CI [0.445–1.828]).

Conclusions

High expression of miRNA-21 and miRNA-214 and low expression of miRNA-34a, miRNA-133a and miRNA-539 were associated with poor prognosis of OS patients after adjusting for TNM stage, metastasis or recurrence and miRNA-30c.

miRNA signatures in childhood sarcomas and their clinical implications

Progresses in multimodal treatments have significantly improved the outcomes for childhood cancer. Nonetheless, for about one-third of patients with Ewing sarcoma, rhabdomyosarcoma, or osteosarcoma steady remission has remained intangible. Thus, new biomarkers to improve early diagnosis and the development of precision-targeted medicine remain imperative. Over the last decade, remarkable progress has been made in the basic understanding of miRNAs function and in interpreting the contribution of their dysregulation to cancer development and progression. On this basis, this review focuses on what has been learned about the pivotal roles of miRNAs in the regulation of key genes implicated in childhood sarcomas.

Silencing of long-non-coding RNA ANCR suppresses the migration and invasion of osteosarcoma cells by activating the p38MAPK signalling pathway

Background

Osteosarcoma (OS) is a malignancy of the bone that has no clearly identified prognostic factors for diagnosis. In this study, we evaluated the regulatory role of long non-coding RNA (lncRNA) ANCR on the migration and invasion of OS cells as well as the possible mechanism involving the p38MAPK signalling pathway.

Methods

ANCR expression was determined in OS tissues and OS cell lines (MG-63, S1353, U2OS, and UMR-106) by qRT-PCR. It was observed that ANCR was down-regulated in MG-63 and U2OS cells by 48 h of siRNA-ANCR (si-ANCR) transfection. The proliferation of transfected cells was determined using the CCK-8 and the EdU assays. The migration and invasion of transfected cells were determined by the Transwell assay. The expression of E-cadherin, N-cadherin, and phosphorylated p38MAPK (p-p38MAPK) proteins was determined by Western blot. In addition, combinatorial treatment of cells with si-ANCR + SB203580 (p38MAPK inhibitor) was performed to investigate the association between ANCR and MAPK signalling in OS cells.

Results

ANCR was up-regulated in OS cells and tissues. ANCR silencing significantly inhibited the proliferation rate, decreased the percentage of migration and invasion cells, down-regulated N-cadherin, and up-regulated E-cadherin and p-p38MAPK in MG-63 and U2OS cells. Inhibition of the p38MAPK signalling pathway (SB203580) in MG-63 and U2OS cells rescued si-ANCR-induced inhibition of cell migration and invasion.

Conclusions

Silencing of ANCR inhibited the migration and invasion of OS cells through activation of the p38MAPK signalling pathway.

Non-Coding RNAs in Pediatric Solid Tumors

Pediatric solid tumors are a diverse group of extracranial solid tumors representing approximately 40% of childhood cancers. Pediatric solid tumors are believed to arise as a result of disruptions in the developmental process of precursor cells which lead them to accumulate cancerous phenotypes. In contrast to many adult tumors, pediatric tumors typically feature a low number of genetic mutations in protein-coding genes which could explain the emergence of these phenotypes. It is likely that oncogenesis occurs after a failure at many different levels of regulation. Non-coding RNAs (ncRNAs) comprise a group of functional RNA molecules that lack protein coding potential but are essential in the regulation and maintenance of many epigenetic and post-translational mechanisms. Indeed, research has accumulated a large body of evidence implicating many ncRNAs in the regulation of well-established oncogenic networks. In this review we cover a range of extracranial solid tumors which represent some of the rarer and enigmatic childhood cancers known. We focus on two major classes of ncRNAs, microRNAs and long non-coding RNAs, which are likely to play a key role in the development of these cancers and emphasize their functional contributions and molecular interactions during tumor formation.

MicroRNA-449b-5p Suppresses Proliferation, Migration, and Invasion of Osteosarcoma by Targeting c-Met

Background

The aim of this study was to clarify the biological function of microRNA-449b-5p in the progression of osteosarcoma (OS) and to define the underlying mechanism.

Material/Methods

Relative levels of microRNA-449b-5p in OS tissues and cell lines was determined by quantitative real-time polymerase chain reaction (qRT-PCR). The correlation between microRNA-449b-5p level and pathological characteristics of OS patients was analyzed by chi-square test. Kaplan-Meier analysis was used for survival analysis of OS patients based on their expression level of microRNA-449b-5p. Regulatory effects of microRNA-449b-5p on cellular behaviors of OS cells were evaluated by cell counting kit-8 (CCK-8) and Transwell assay. The binding relationship between microRNA-449b-5p and c-Met was verified through dual-luciferase reporter gene assay, and their interaction in OS progression was further examined through a series of rescue experiments.

Results

MicroRNA-449b-5p was expressed at low levels in OS. Lower levels of microRNA-449b-5p were seen in OS tissues with worse tumor grade or histological differentiation. OS patients with low levels of microRNA-449b-5p had worse overall survival relative to those with high level of microRNA-449b-5p. Overexpression of microRNA-449b-5p markedly attenuated proliferative, migratory, and invasive abilities of OS cells. C-Met is the downstream target of microRNA-449b-5p, and its level was inhibited in OS cells overexpressing microRNA-449b-5p. Importantly, c-Met partially rescued the inhibitory effects of microRNA-449b-5p on behavior of OS cells.

Conclusions

MicroRNA-449b-5p is downregulated in OS, which alleviates the malignant progression of OS by targeting c-Met.

Next-generation sequencing predicts interaction network between miRNA and target genes in lipoteichoic acid-stimulated human neutrophils

Toll-like receptors (TLRs), which are a class of pattern-recognition receptors, can sense specific molecules of pathogens and then activate immune cells, such as neutrophils. The regulation of TLR signaling in immune cells has been investigated by various studies. However, the interaction of TLR signaling-activated microRNAs (miRNAs) and genes has not been well investigated in a specific type of immune cells. In the present study, neutrophils were isolated from peripheral blood of a healthy donor, and then treated for 16 h with Staphylococcus aureus lipoteichoic acid (LTA), which is an agonist of TLR2. The miRNA and mRNA expression profiles were analyzed via next-generation sequencing and bioinformatics approaches. A total of 290 differentially expressed genes between LTA-treated and vehicle-treated neutrophils were identified. Gene ontology analysis revealed that various biological processes and pathways, including inflammatory responses, defense response, positive regulation of cell migration, motility, and locomotion, and cell surface receptor signaling pathway, were significantly enriched. In addition, 38 differentially expressed miRNAs were identified and predicted to be involved in regulating signal transduction and cell communication. The interaction of 4 miRNAs (hsa-miR-34a-5p, hsa-miR-34c-5p, hsa-miR-708-5p, and hsa-miR-1271-5p) and 5 genes (MET, CACNB3, TNS3, TTYH3, and HBEGF) was proposed to participate in the LTA-induced signaling network. The present findings may provide novel information for understanding the detailed expression profiles and potential networks between miRNAs and their target genes in LTA-stimulated healthy neutrophils.

microRNA-613 exerts anti-angiogenic effect on nasopharyngeal carcinoma cells through inactivating the AKT signaling pathway by down-regulating FN1

Background: Nasopharyngeal carcinoma (NPC) is a disease highly sensitive to radiotherapy with the unclear etiology. However, the specific effects of microRNA-613 (miR-613) on NPC still remain elusive. Therefore, the present study probes into the underlying mechanism of miR-613 in NPC via AKT signaling pathway by regulating Fibronectin 1 (FN1).

Methods: First, microarray analysis was used to screen differentially expressed genes (DEGs) and regulatory miRs associated with NPC. Next, miR-613 and FN1 expression in NPC cells was determined, followed by verification of target relationship between miR-613 and FN1. With NPC cells exposed to miR-613 mimic, si-FN1 and LY294002 (inhibitor of AKT signaling pathway), the regulatory effects of miR-613 on proliferation, apoptosis, invasion, migration and angiogenesis of NPC cells were detected with ratio of B-cell lymphoma 2/Bcl-2-associated X protein (Bcl-2/Bax), Cleaved-caspase3, matrix metallopeptidase 2 (MMP-2), MMP-9, vascular endothelial growth factor (VEGF), and cell adhesion molecule-1 (CD31) expression measured. Then, tumorigenesis and MVD were determined after Xenograft in nude mice.

Results: FN1 modulated by miR-613 was critical for NPC via the AKT signaling pathway. NPC cells exhibited down-regulated miR-613 and up-regulated FN1. Besides, miR-613 was verified to target FN1. Moreover, overexpressed miR-613, silenced FN1 or LY294002 treatment suppressed proliferation, invasion, migration, and angiogenesis in NPC cells, which was indicated by reduced expression of AKT, mTOR, MMP-2, MMP-9, VEGF, and CD31 as well as decreased ratio of Bcl-2/Bax and increased expression of Cleaved-caspase3. Furthermore, cell apoptosis was promoted and tumorigenesis and MVD in nude mice were inhibited with overexpression of miR-613, silenced FN1 or LY294002 treatment.

Conclusion: Taken together, miR-613 inhibits angiogenesis in NPC cells through inactivating FN1-dependent AKT signaling pathway.

Noncoding RNAs as circulating biomarkers in osteosarcoma patients

Noncoding RNAs (ncRNAs) identify a large family of RNAs that do not encode proteins and represent an important group of tumor biomarkers, directly involved in the process of tumor pathogenesis and progression. Many of them have also been identified in biological fluids of patients with cancer, especially blood, suggesting their role as an emerging class of circulating biomarkers. Many ncRNAs, both miRNAs and lncRNAs, are deregulated in sarcoma tissues, with the most consistent data in osteosarcomas. In patients with osteosarcoma, the role of ncRNAs as circulating biomarkers is taking enormous value, above all for their ability to vary expression levels during disease progression and in response to therapy. In this mini-review, we summarize the main studies supporting the role of circulating ncRNAs in monitoring disease status in patients with osteosarcoma.

Innate extracellular vesicles from melanoma patients suppress β-catenin in tumor cells by miRNA-34a

Upon tumor development, new extracellular vesicles appear in circulation. Our knowledge of their relative abundance, function, and overall impact on cancer development is still preliminary. Here, we demonstrate that plasma extracellular vesicles (pEVs) of non-tumor origin are persistently increased in untreated and post-excision melanoma patients, exhibiting strong suppressive effects on the proliferation of tumor cells. Plasma vesicle numbers, miRNAs, and protein levels were elevated two- to tenfold and detected many years after tumor resection. The vesicles revealed individual and clinical stage-specific miRNA profiles as well as active ADAM10. However, whereas pEV from patients preventing tumor relapse down-regulated β-catenin and blocked tumor cell proliferation in an miR-34a-dependent manner, pEV from metastatic patients lost this ability and stimulated β-catenin-mediated transcription. Cancer-induced pEV may constitute an innate immune mechanism suppressing tumor cell activity including that of residual cancer cells present after primary surgery.

Down-regulation of microRNA-31-5p inhibits proliferation and invasion of osteosarcoma cells through Wnt/β-catenin signaling pathway by enhancing AXIN1

OBJECTIVES

Recently, the role of microRNA-31-5p (miR-31-5p) in gene expression regulation has been reported in various cancers. Studies have shown that Wnt/β-catenin signaling pathway is involved in the proliferation and invasion of osteosarcoma (OS) cells. Therefore, this study aims to probe into the regulatory role of miR-31-5p targeting AXIN1 in OS cells through Wnt/β-catenin signaling pathway.

METHODS

Firstly, microarray expression profiles were used to screen differentially expressed miRNAs associated with OS. Next, OS and normal fibrous connective tissues as well as OS cell lines were obtained for investigating the role of miR-31-5p on OS. Then, the putative binding sites between miR-31-5p and AXIN1 were predicted and verified. The regulatory effects of miR-31-5p on proliferation and invasion as well as tumorigenic potential of OS cells targeting AXIN1 were also analyzed. Besides, the relationship between miR-31-5p and Wnt/β-catenin signaling pathway was assessed by immunofluorescence staining.

RESULTS

The microarray dataset GSE63939 showed that miR-31-5p and AXIN1 were involved in OS. miR-31-5p expression increased while the expression of AXIN1 decreased in OS tissues and cells. AXIN1 was identified as a target gene of miR-31-5p, intense expression of which inhibited the transcription of AXIN1. Down-regulated miR-31-5p suppressed proliferation, invasion and tumorigenicity of OS cells through promoting AXIN1. Decreased miR-31-5p activated Wnt/β-catenin signaling pathway, as reflected by increased β-catenin translocation into nuclei, through up-regulating the transcription of AXIN1.

CONCLUSIONS

All in all, repression of miR-31-5p targets AXIN1 to activate the Wnt/β-catenin signaling pathway, thus suppressing proliferation, invasion and tumorigenicity of OS cells.

MicroRNA-876-5p inhibits cell proliferation, migration and invasion by targeting c-Met in osteosarcoma

Recently, aberrant expression of miR‐876‐5p has been reported to participate in the progression of several human cancers. However, the expression and function of miR‐876‐5p in osteosarcoma (OS) are still unknown. Here, we found that the expression of miR‐876‐5p was significantly down‐regulated in OS tissues compared to para‐cancerous tissues. Clinical association analysis indicated that underexpression of miR‐876‐5p was positively correlated with advanced clinical stage and poor differentiation. More importantly, OS patients with low miR‐876‐5p level had a significant shorter overall survival compared to miR‐876‐5p high‐expressing patients. In addition, gain‐ and loss‐of‐function experiments demonstrated that miR‐876‐5p restoration suppressed whereas miR‐876‐5p knockdown promoted cell proliferation, migration and invasion in both U2OS and MG63 cells. In vivo studies revealed that miR‐876‐5p overexpression inhibited tumour growth of OS in mice. Mechanistically, miR‐876‐5p reduced c‐Met abundance in OS cells and inversely correlated c‐Met expression in OS tissues. Herein, c‐Met was recognized as a direct target of miR‐876‐5p using luciferase reporter assay. Notably, c‐Met restoration rescued miR‐876‐5p attenuated the proliferation, migration and invasion of OS cells. In conclusion, these findings indicate that miR‐876‐5p may be used as a potential therapeutic target and promising biomarker for the diagnosis and prognosis of OS.

Minor allele of rs1057317 polymorphism in TLR4 is associated with increased risk of Helicobacter pylori -induced gastric cancer

BACKGROUND

Helicobacter pylori (HP) plays a significant role in the carcinogenesis of gastric cancer (GC), the second leading cause of cancer-related death worldwide. The aim of this study was to investigate the effect of rs1057317 polymorphism on the interaction between microRNA-034a (miR-034a) and toll-like receptor 4 (TLR4), and their involvement in the HP-associated GC.

METHODS

Computation analyses, real-time polymerase chain reaction, enzyme-linked immunosorbent assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and luciferase assays were performed to identify potential miRNAs involved in the carcinogenesis of HP-induced GC. Subsequently, the effect of miR-34a and recombinant TNFα-interacting protein α (rTip-α) on the expression of TLR4, interleukin (IL)-6, and tumor necrosis factor α (TNF-α) was measured.

RESULTS

Three hundred and twelve HP-positive GC patients (HP+ GC) and 380 HP-negative GC patients (HP- GC) were enrolled into this study. It was found that, in HP-positive patient, the AA genotype of the rs1057317 polymorphism was closely associated with the risk of GC (95% confidence interval, 1.12 to 2.70; odds ratio, 1.74; P = 0.0129). Furthermore, between the HP+ GC and HP- GC groups, miR-34a was the only miRNA showing a significantly different expression. Subsequently, TLR4 was identified as a target gene of miR-34a. Interestingly, miR-34a evidently reduced the expression of TLR4 3'-untranslated region (3'-UTR) containing the C allele of the rs1057317 polymorphism, but the TLR4 3'-UTR containing the A allele in the rs1057317 was not affected by miR-34a. In addition, the expression of IL-6 and TNF-α was significantly downregulated by miR-34a, but increased by rTip-α. Both miR-34a and rTip-α could enhance the viability of cells, although the effect of rTip-α was stronger.

CONCLUSION

The data of this study suggested that the rs1057317 polymorphism in the miR-34a binding site of TLR4 may predict the risk of HP-induced GC.

MicroRNA-206 Reduces Osteosarcoma Cell Malignancy In Vitro by Targeting the PAX3-MET Axis

PURPOSE

This study was undertaken to explore how miR-206 represses osteosarcoma (OS) development.

MATERIALS AND METHODS

Expression levels of miR-206, PAX3, and MET mRNA were explored in paired OS and adjacent tissue specimens. A patient-derived OS cell line was established. miR-206 overexpression and knockdown were achieved by lentiviral transduction. PAX3 and MET overexpression were achieved by plasmid transfection. Treatment with hepatocyte growth factor (HGF) was utilized to activate c-Met receptor. Associations between miR-206 and PAX3 or MET mRNA in OS cells were verified by AGO2-RNA immunoprecipitation assay and miRNA pulldown assay. OS cell malignancy was evaluated in vitro by cell proliferation, metastasis, and apoptosis assays. PAX3 and MET gene expression in OS cells was assayed by RT-qPCR and Western blot. Activation of PI3K-AKT and MAPK-ERK in OS cells were assayed by evaluating Akt1 Ser473 phosphorylation and total threonine phosphorylation of Erk1/2, respectively.

RESULTS

Expression levels of miR-206 were significantly decreased in OS tissue specimens, compared to adjacent counterparts, and were inversely correlated with expression of PAX3 and MET mRNA. miR-206 directly interacted with PAX3 and MET mRNA in OS cells. miR-206 overexpression significantly reduced PAX3 and MET gene expression in OS cells in vitro, resulting in significant decreases in Akt1 and Erk1/2 activation, cell proliferation, and metastasis, as well as increases in cell apoptosis, while miR-206 knockdown showed the opposite effects. The effects of miR-206 overexpression on OS cells were reversed by PAX3 or MET overexpression, but only partially attenuated by HGF treatment.

CONCLUSION

miR-206 reduces OS cell malignancy in vitro by targeting PAX3 and MET gene expression.

MicroRNA-34a promotes CMECs apoptosis and upregulate inflammatory cytokines, thus worsening CMECs damage and inhibiting angiogenesis by negatively targeting the Notch signaling pathway

OBJECTIVE

Recently, microRNA-34a (miR-34a) has been reported to lead to secretion of proinflammatory cytokine in endothelial cells, whereas whether miR-34a plays a protective role in damaged cardiac microvascular endothelial cells (CMECs) remains to be determined. Herein, the purpose of this study is to explore the effect of miR-34a in mediating Notch signaling pathway in apoptosis and angiogenesis of damaged CMECs.

METHODS

The primary mice CMECs were isolated, cultivated, and identified before establishment of damaged CMEC model by incubation with homocysteine (HCY) for 24 hours. Quantitative reverse-transcription polymerase chain reaction and Western blot analysis were applied to determine the expressions of miR-34a and Notch1. Cell viability and cell apoptosis were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and Hochest 33258 staining. Capillary-like structures formation assay was used to detect the capillary-like structures in CMECs. The expressions of inflammatory cytokines and angiogenesis factors were determined by enzyme-linked immunosorbent assay.

RESULTS

In contrast to the blank group, the HCY and negative control groups demonstrated with elevated expressions of miR-34a, interleukin (IL)-1β, IL-6, and increased cell apoptosis rate, but decreased expressions of Notch1, IL-10, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and human growth factor (HGF), as well as attenuated cell viability and capillary-like structures of cells formation ability. In comparison with HCY group, the expressions of miR-34a, IL-1β, IL-6, and apoptosis rate were increased, whereas the expressions of Notch1, VEGF, bFGF, HGF, cell viability, and capillary-like structures of cells formation were inhibited in miR-34a mimic group.

CONCLUSION

This study demonstrates that miR-34a can promote CMEC apoptosis and upregulate inflammatory cytokines, thus worsening CMEC damage and inhibiting angiogenesis by negatively targeting the Notch signaling pathway.

A genetically engineered microRNA-34a prodrug demonstrates anti-tumor activity in a canine model of osteosarcoma

Osteosarcoma (OSA) represents the most common primary bone tumor in humans and pet dogs. Little progress has been made with regard to viable treatment options in the past three decades and patients presenting with metastatic disease continue to have a poor prognosis. Recent mouse studies have suggested that microRNA-34a (miR-34a) may have anti-tumor activities in human OSA models. Due to the conservation of microRNA across species, we hypothesized that a bioengineered miR-34a prodrug (tRNA/miR-34a) would have similar effects in canine OSA, providing a valuable preclinical model for development of this therapeutic modality. Using a panel of canine OSA cell lines, we found that tRNA/miR-34a reduced viability, clonogenic growth, and migration and invasion while increasing tumor cell apoptosis. Furthermore, canine OSA cells successfully process the tRNA/miR-34a into mature miR-34a which reduces expression of target proteins such as platelet derived growth factor receptor alpha (PDGFRα), Notch1 and vascular endothelial growth factor (VEGF). Additionally, our subcutaneous OSA xenograft model demonstrated in vivo tumor growth delay, increased necrosis and apoptosis by tRNA/miR-34a, and decreased cellular proliferation ability. Taken together, these data support that this novel microRNA-based therapy may possess clinical utility in a spontaneously-occurring large animal model of OSA, which can then serve to inform the clinical development of this therapy for human OSA patients.

Down-Regulated microRNA-34a Expression as a Prognostic Marker for Poor Osteosarcoma in Mice: A Systematic Review and Meta-Analysis

Background: In children and adolescents, osteosarcomais the most common malignant bone tumor with a high mortality rate. New therapeutic strategies are urgent to be explored. Studies have proven that microRNAs (miRNAs) in malignant tumors often appear dysregulation, this provides a direction for exploring the new therapeutic strategies for cancers. The aim of this meta-analysis is to summarize and analyze whethermicroRNA-34a(miRNA-34a) could be a prognostic marker for osteosarcoma in mice.

Methods: We searched PubMed, Web of Science, Embase, Wan Fang Database, China Knowledge Resource Integrated Database, VIP Database, and SinoMed since their initiation date to January 24, 2018. After screening based on inclusion and exclusion criteria, eight articles were included for the final analysis.

Results: Our results showed that tumor volume and tumor weight were inhibited by restoring the down-regulated expression of miRNA-34a in the xenograft mouse models.

Conclusions: Down-regulated miRNA-34a expression is a prognostic marker for poor osteosarcoma. We should be more committed to investigate the clinical significance of miRNA-34a in osteosarcoma patients.

A comprehensive investigation using meta-analysis and bioinformatics on miR-34a-5p expression and its potential role in head and neck squamous cell carcinoma

HNSCC is the sixth most common cancer worldwide and is characterized as an aggressive, malignant tumor. MiR-34a-5p (miR-34a) expression has been strongly linked to HNSCC development. However, the exact target gene of miRNA-34a-as well as its biological and mechanistic pathways-are unclear. It is critical that the clinical value of HNSCC receive further study. We conducted a continuous variable, meta-analysis from data found in the cancer literature as well as that provided by the Cancer Genome Atlas (TCGA) to estimate miR-34a expression in HNSCC. Next, TCGA database, microarray, and MiRWalk were all used to predict the target gene of miR-34a in HNSCC. Then, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to explore the underlying molecular mechanism of miR-34a in HNSCC. Finally, we used Spearman's analysis and survival curves to identify the roles of related target genes involved in significant pathways during the development of HNSCC. Expression levels of miR-34a in HNSCC were significant lower than those in normal tissues (P<0.05) and summary receiver operating characteristic (sROC) was 0.72. The collective results obtained from KEGG and GO indicated that miR-34a may be involved in the development of HNSCC via known cancer pathways, including the p53 and/or PI3K-Akt signalling pathways. Our results suggested miR-34a has potential use as a novel, non-invasive and highly sensitive biomarker for diagnostic in HNSCC. Finally, it likely plays an essential role in the deterioration and ultimate tumorigenesis of HNSCC through determined cancer pathways.

Investigation of miR-490-3p Expression in Hepatocellular Carcinoma Based on Reverse Transcription-Polymerase Chain Reaction (RT-qPCR) and a Meta-Analysis of 749 Cases

Background

miR-490-3p could play vital roles in multiple cancers. However, the role of miR-490-3p in hepatocellular carcinoma (HCC) remains uncertain. In this study, we sought to explore the underlying role of miR-490-3p in HCC.

Material/Methods

In this study, we explored the clinical role of miR-490-3p in HCC via quantitative reverse transcription–polymerase chain reaction (RT-qPCR) and The Cancer Genome Atlas (TCGA) database. Then, a meta-analysis was performed to evaluate the expression trend and diagnostic value of miR-490-3p in HCC. Furthermore, 12 miRNA prediction algorithms were applied to predict the potential target genes of miR-490-3p. The differentially expressed genes in HCC in the Gene Expression Profiling Interactive Analysis (GEPIA) database were also selected. Additionally, bioinformatics analyses were utilized to investigate the possible functions and pathways of the target genes.

Results

miR-490-3p was clearly down-regulated in HCC based on RT-qPCR (P=0.002). Consistent with the results of RT-qPCR, miR-490 was more highly expressed in normal liver tissue than in HCC (P<0.001). Additionally, the meta-analysis confirmed the results from RT-qPCR and TCGA. Furthermore, based on the prediction algorithms and GEPIA, a total of 113 genes were selected. According to the bioinformatics analyses, we found that the most remarkably enriched functional terms included protein transport, poly(A) RNA binding, and intracellular organelle part. Additionally, the miR-490-3p target genes were significantly related to the pathways in cancer.

Conclusions

We found that miR-490-3p is down-regulated in HCC and is related to genes that have potential tumoral functions. However, the exact mechanism should be confirmed by functional experiments.

miR-34a exerts as a key regulator in the dedifferentiation of osteosarcoma via PAI-1-Sox2 axis

Osteosarcoma (OS) is a malignant bone cancer with severe chromosomal abnormalities and genetic aberrations. Our previous work reported the dedifferentiation of OS, which is related to poor prognosis. However, the molecular mechanism that regulates OS dedifferentiation is still a subject of exploration. Emerging evidence has suggested that microRNAs (miRNAs) are associated with the pathogenesis of OS and could potentially be developed for use as diagnostic biomarkers and therapeutic strategies. In the present study, we intended to illustrate the role of miR-34a in the dedifferentiation of OS. Upregulation of miR-34a was observed while OS cells were induced into stem-like phenotype. Notably, inhibition of miR-34a could promote the reprogramming transition of OS. Further exploration on the downstream network of miR-34a identified that blocking plasminogen activator inhibitor-1 (PAI-1) expression could restrain OS dedifferentiation into cancer stem-like cells by downregulating SRY-related-HMG box (Sox) 2. We also showed that Sox2 overexpression rescued the suppression phenotype driven by PAI-1 inhibition. Conversely, PAI-1 inhibitor (PAI-039) could suppress the upregulation of Sox2 expression caused by miR-34a inhibition. Be applying bone extracellular matrix (BEM)-OS models, we demonstrated the phenotypic heterogeneity of OS cells, consistent with a strong concordance between PAI-1 and Sox2 expression levels. Taken together, our findings proved miR-34a to be a bona fide suppressor involved in the regulation of OS dedifferentiation. Targeting miR-34a or its direct target PAI-1 could offer new strategies for OS treatment.

Genome-wide identification, expression profiling, and target gene analysis of microRNAs in the Onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), vectors of tospoviruses (Bunyaviridae)

Thrips tabaci Lindeman is an important polyphagous insect pest species estimated to cause losses of more than U.S. $1 billion worldwide annually. Chemical insecticides are of limited use in the management of T. tabaci due to the thigmokinetic behavior and development of resistance to insecticides. There is an urgent need to find alternative management strategies. Small noncoding RNAs (sncRNAs) especially microRNAs (miRNAs) hold great promise as key regulators of gene expression in a wide range of organisms. MiRNAs are a group of endogenously originated sncRNA known to regulate gene expression in animals, plants, and protozoans. In this study, we explored these RNAs in T. tabaci using deep sequencing to provide a basis for future studies of their biological and physiological roles in governing gene expression. Apart from snoRNAs and piRNAs, our study identified nine novel and 130 known miRNAs from T. tabaci. Functional classification of the targets for these miRNAs predicted that majority are involved in regulating transcription, translation, signal transduction and genetic information processing. The higher expression of few miRNAs (such as tta-miR-281, tta-miR-184, tta-miR-3533, tta-miR-N1, tta-miR-N7, and tta-miR-N9) in T. tabaci pupal and adult stages reflected their possible role in larval and adult development, metamorphosis, parthenogenesis, and reproduction. This is the first exploration of the miRNAome in T. tabaci, which not only provides insights into their possible role in insect metamorphosis, growth, and development but also offer an important resource for future pest management strategies.

Regulatory effects of microRNA‑184 on osteosarcoma via the Wnt/β‑catenin signaling pathway

The present study aimed to investigate the role of microRNA (miRNA/miR)‑184 in osteosarcoma growth, development and metastasis, and the effects of miRNA‑184 on the proliferation, invasion and metastasis of osteosarcoma cells and associated mechanisms. In vitro, miR‑184 was transfected into U‑2OS cells and 143B cells. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was used to detect the expression of miR‑184. MTT was utilized to detect cell proliferation. A Transwell assay was applied to detect cell invasiveness. In vivo, an osteosarcoma tibial orthotopic metastatic tumor model was established, and western blotting and RT‑qPCR were used to detect the expression of Wnt and β‑catenin. Following the overexpression of miR‑184, the proliferation and cell invasion ability were significantly increased in U‑2OS and 143B cells. Following inhibition of miR‑184, cell proliferation and cell invasion ability were significantly decreased. In nude mice, tumor volume significantly increased following overexpression of miR‑184, and Wnt and phosphorylated β‑catenin levels were significantly increased. Following miR‑184 inhibition, tumor volume was significantly decreased, and Wnt and phosphorylated β‑catenin levels were significantly decreased. The results of the present study indicated that the Wnt/β‑catenin signaling pathway serves a key function in the mechanism of osteosarcoma. Inhibition of miRNA‑184 may reduce tumor volume of osteosarcoma via regulation of the Wnt/β‑catenin signaling pathway and may provide a novel strategy for the future diagnosis and treatment of osteosarcoma.

lncRNA C2dat1 Promotes Cell Proliferation, Migration, and Invasion by Targeting miR-34a-5p in Osteosarcoma Cells

Osteosarcoma is a highly aggressive malignant bone tumor with poor prognosis. Evidence has suggested that lncRNAs are deregulated in multiple cancers. In this study, we investigated the role of the lncRNA C2dat1 on the biological functions of osteosarcoma cells. The expressions of C2dat1, miR-34a-5p, and Sirt1 in human osteosarcoma cells were altered by transfection with their specific vectors/shRNA or mimic/inhibitor. Cell viability, migration, invasion, and apoptosis were assessed posttransfection. The mRNA and protein levels of C2dat1, miR-34a-5p, and Sirt1 were detected by qRT-PCR and Western blot. The results showed that C2dat1 suppression reduced cell viability, invasion, and migration, whereas it increased cell apoptosis in OS-732 cells. The expression of miR-34a-5p was downregulated when C2dat1 was overexpressed, whereas it negatively regulated Sirt1 expression. miR-34a-5p overexpression inhibited cell viability, migration, and invasion and promoted cell apoptosis in osteosarcoma cells by downregulation of Sirt1. Furthermore, miR-34a-5p overexpression deactivated the p38/ERK/AKT and Wnt/β-catenin signaling pathways by inhibition of Sirt1.