MicroRNA-34a functions as a potential tumor suppressor by inducing apoptosis in neuroblastoma cells

MicroRNA-145 attenuates IL-6-induced enhancements of sensitivity to UVB irradiation by suppressing MyD88 in HaCaT cells

MicroRNAs (miRNAs/miRs) play vital roles in various immune diseases including systemic lupus erythematosus (SLE). The current study aimed to assess the role of miR-145 in interleukin-6 (IL-6)-treated HaCaT cells under ultraviolet B (UVB) irradiation and further explore the potential regulatory mechanism. HaCaT cells were pretreated with IL-6 and then exposed to UVB to assess the effect of IL-6 on sensitivity of HaCaT cells to UVB irradiation. The levels of miR-145 and MyD88 were altered by transfection and the transfected efficiency was verified by quantitative reverse transcription polymerase chain reaction (qRT-PCR)/western blot analysis. Cell viability, percentage of apoptotic cells and expression levels of apoptosis-related factors were measured by trypan blue assay, flow cytometry assay, and western blot analysis, respectively. In addition, the levels of c-Jun N-terminal kinases (JNK) and nuclear factor-κB (NF-κB) signaling pathway-related factors were assessed by western blot analysis. IL-6 treatments significantly aggravated the reduction of cell viability and promotion of cell apoptosis caused by UVB irradiation in HaCaT cells. Interestingly, miR-145 level was augmented by UVB exposure and miR-145 mimic alleviated IL-6-induced increase of sensitivity to UVB irradiation in HaCaT cells, as dramatically increased cell viability and reduced cell apoptosis. Opposite effects were observed in miR-145 inhibitor-transfected cells. Meanwhile, MyD88 was negatively regulated by miR-145 and MyD88 mediated the regulatory effect of miR-145 on IL-6- and UVB-treated cells. In addition, miR-145 mimic inhibited the JNK and NF-κB pathways by down-regulating MyD88. In conclusion, the present study demonstrated that miR-145 alleviated IL-6-induced increase of sensitivity to UVB irradiation by down-regulating MyD88 in HaCaT cells.

An integrated approach of bioinformatic prediction and in vitro analysis identified that miR-34a targets MET and AXL in triple-negative breast cancer

BACKGROUND

Breast cancer is the most prevalent cancer among women, and AXL and MET are the key genes in the PI3K/AKT/mTOR pathway as critical elements in proliferation and invasion of cancer cells. MicroRNAs (miRNAs) are small non-coding RNAs regulating the expression of genes.

METHODS

Bioinformatic approaches were used to find a miRNA that simultaneously targets both AXL and MET 3'-UTRs. The expression of target miRNA was evaluated in triple-negative (MDA-MB-231) and HER2-overexpressing (SK-BR-3) breast cancer cell lines as well as normal breast cells, MCF-10A, using quantitative real-time PCR. Then, the miRNA was overexpressed in normal and cancer cell lines using a lentiviral vector system. Afterwards, effects of overexpressed miRNA on the expression of AXL and MET genes were evaluated using quantitative real-time PCR.

RESULTS

By applying bioinformatic software and programs, miRNAs that target the 3'-UTR of both AXL and MET mRNAs were determined, and according to the scores, miR-34a was selected for further analyses. The expression level of miR-34a in MDA-MB-231 and SK-BR-3 was lower than that of MCF-10A. Furthermore, AXL and MET expression in SK-BR-3 and MDA-MB-231 was lower and higher, respectively, than that of MCF-10A. After miR-34a overexpression, MET and AXL were downregulated in MDA-MB-231. In addition, MET was downregulated in SK-BR-3, while AXL was upregulated in this cell line.

CONCLUSIONS

These findings may indicate that miR-34a is an oncogenic miRNA, downregulated in the distinct breast cancer subtypes. It also targets MET and AXL 3'-UTRs in triple-negative breast cancer. Therefore, it can be considered as a therapeutic target in this type of breast cancer.

Dual biomarkers long non-coding RNA GAS5 and microRNA-34a co-expression signature in common solid tumors

Accumulating evidence indicates that non-coding RNAs including microRNAs (miRs) and long non-coding RNAs (lncRNAs) are aberrantly expressed in cancer, providing promising biomarkers for diagnosis, prognosis and/or therapeutic targets. We aimed in the current work to quantify the expression profile of miR-34a and one of its bioinformatically selected partner lncRNA growth arrest-specific 5 (GAS5) in a sample of Egyptian cancer patients, including three prevalent types of cancer in our region; renal cell carcinoma (RCC), glioblastoma (GB), and hepatocellular carcinoma (HCC) as well as to correlate these expression profiles with the available clinicopathological data in an attempt to clarify their roles in cancer. Quantitative real-time polymerase chain reaction analysis was applied. Different bioinformatics databases were searched to confirm the potential miRNAs-lncRNA interactions of the selected ncRNAs in cancer pathogenesis. The tumor suppressor lncRNA GAS5 was significantly under-expressed in the three types of cancer [0.08 (0.006-0.38) in RCC, p <0.001; 0.10 (0.003-0.89) in GB, p < 0.001; and 0.12 (0.015-0.74) in HCC, p < 0.001]. However, levels of miR-34a greatly varied according to the tumor type; it displayed an increased expression in RCC [4.05 (1.003-22.69), p <0.001] and a decreased expression in GB [0.35 (0.04-0.95), p <0.001]. Consistent to the computationally predicted miRNA-lncRNA interaction, negative correlations were observed between levels of GAS5 and miR-34a in RCC samples (r = -0.949, p < 0.001), GB (r = -0.518, p < 0.001) and HCC (r = -0.455, p = 0.013). Kaplan-Meier curve analysis revealed that RCC patients with down-regulated miR-34a levels had significantly poor overall survival than their corresponding (p < 0.05). Hierarchical clustering analysis showed RCC patients could be clustered by GAS5 and miR-34a co-expression profile. Our results suggest potential applicability of GAS5 and miR-34a with other conventional markers for various types of cancer. Further functional validation studies are warranted to confirm miR-34a/GAS5 interplay in cancer.

Etoposide-resistance in a neuroblastoma model cell line is associated with 13q14.3 mono-allelic deletion and miRNA-15a/16-1 down-regulation

Drug resistance is the major obstacle in successfully treating high-risk neuroblastoma. The aim of this study was to investigate the basis of etoposide-resistance in neuroblastoma. To this end, a MYCN-amplified neuroblastoma cell line (HTLA-230) was treated with increasing etoposide concentrations and an etoposide-resistant cell line (HTLA-ER) was obtained. HTLA-ER cells, following etoposide exposure, evaded apoptosis by altering Bax/Bcl2 ratio. While both cell populations shared a homozygous TP53 mutation encoding a partially-functioning protein, a mono-allelic deletion of 13q14.3 locus, where the P53 inducible miRNAs 15a/16-1 are located, and the consequent miRNA down-regulation were detected only in HTLA-ER cells. This event correlated with BMI-1 oncoprotein up-regulation which caused a decrease in p16 tumor suppressor content and a metabolic adaptation of HTLA-ER cells. These results, taken collectively, highlight the role of miRNAs 15a/16-1 as markers of chemoresistance.

miR-665 targets c-MYC and HDAC8 to inhibit murine neuroblastoma cell growth

Neuroblastoma is a common tumor of the peripheral nervous system in children. Highly aggressive MYC-driven neuroblastoma is defined by increased c-MYC and/or MYCN expression. This study employed a mouse neuroblastoma cell model to assess the role of miR-665 in tumorigenesis. We found that miR-665 suppresses mRNAs, targeting c-MYC and HDAC8, which are involved in neuroblastoma tumorigenesis. N6,2'-O-dibutyryladenosine 3':5'cyclic monophosphate (Bt2cAMP) inhibited neuroblastoma cell growth by inhibiting c-MYC and HDAC8 expression and activating caspase 3. Bt2cAMP also upregulated miR-665, and miR665 transfection mimicked the effects of Bt2cAMP, including reduced c-MYC and HDAC8 expression, increased caspase 3 activation, and reduced neuroblastoma cell growth. As compared to untreated cells, Bt2cAMP increased the number of cells in G1 phase by 50% and the number in G2-M phase by 5%, while the number of cells in S phase was reduced 2.8-fold. Similarly, miR-665 transfection increased the number of cells in G1 phase by 16% and the number in G2M phase by 2%, and decreased the cells in S-phase by 18%. These findings indicate miR-665 suppresses neuroblastoma tumorigenesis by inhibiting c-MYC and HDAC8 expression and suggest miR-665 has potential as an anti-neuroblastoma therapeutic.

The Network of Non-coding RNAs in Cancer Drug Resistance

Non-coding RNAs (ncRNAs) have been implicated in most cellular functions. The disruption of their function through somatic mutations, genomic imprinting, transcriptional and post-transcriptional regulation, plays an ever-increasing role in cancer development. ncRNAs, including notorious microRNAs, have been thus proposed to function as tumor suppressors or oncogenes, often in a context-dependent fashion. In parallel, ncRNAs with altered expression in cancer have been reported to exert a key role in determining drug sensitivity or restoring drug responsiveness in resistant cells. Acquisition of resistance to anti-cancer drugs is a major hindrance to effective chemotherapy and is one of the most important causes of relapse and mortality in cancer patients. For these reasons, non-coding RNAs have become recent focuses as prognostic agents and modifiers of chemo-sensitivity. This review starts with a brief outline of the role of most studied non-coding RNAs in cancer and then highlights the modulation of cancer drug resistance via known ncRNAs based mechanisms. We identified from literature 388 ncRNA-drugs interactions and analyzed them using an unsupervised approach. Essentially, we performed a network analysis of the non-coding RNAs with direct relations with cancer drugs. Within such a machine-learning framework we detected the most representative ncRNAs-drug associations and groups. We finally discussed the higher integration of the drug-ncRNA clusters with the goal of disentangling effectors from downstream effects and further clarify the involvement of ncRNAs in the cellular mechanisms underlying resistance to cancer treatments.

Inhibition of GPR158 by microRNA-449a suppresses neural lineage of glioma stem/progenitor cells and correlates with higher glioma grades

To identify biomarkers for glioma growth, invasion and progression, we used a candidate gene approach in mouse models with two complementary brain tumour phenotypes, developing either slow-growing, diffusely infiltrating gliomas or highly proliferative, non-invasive primitive neural tumours. In a microRNA screen we first identified microRNA-449a as most significantly differentially expressed between these two tumour types. miR-449a has a target dependent effect, inhibiting cell growth and migration by downregulation of CCND1 and suppressing neural phenotypes by inhibition of G protein coupled-receptor (GPR) 158. GPR158 promotes glioma stem cell differentiation and induces apoptosis and is highest expressed in the cerebral cortex and in oligodendrogliomas, lower in IDH mutant astrocytomas and lowest in the most malignant form of glioma, IDH wild-type glioblastoma. The correlation of GPR158 expression with molecular subtypes, patient survival and therapy response suggests a possible role of GPR158 as prognostic biomarker in human gliomas.

The Nefarious Nexus of Noncoding RNAs in Cancer

The past decade has witnessed enormous progress, and has seen the noncoding RNAs (ncRNAs) turn from the so-called dark matter RNA to critical functional molecules, influencing most physiological processes in development and disease contexts. Many ncRNAs interact with each other and are part of networks that influence the cell transcriptome and proteome and consequently the outcome of biological processes. The regulatory circuits controlled by ncRNAs have become increasingly more relevant in cancer. Further understanding of these complex network interactions and how ncRNAs are regulated, is paving the way for the identification of better therapeutic strategies in cancer.

Endothelial Cell Aging: How miRNAs Contribute?

Endothelial cells (ECs) form monolayers and line the interior surfaces of blood vessels in the entire body. In most mammalian systems, the capacity of endothelial cells to divide is limited and endothelial cells are prone to be senescent. Aging of ECs and resultant endothelial dysfunction lead to a variety of vascular diseases such as atherosclerosis, diabetes mellites, hypertension, and ischemic injury. However, the mechanism by which ECs get old and become senescent and the impact of endothelial senescence on the vascular function are not fully understood. Recent research has unveiled the crucial roles of miRNAs, which are small non-coding RNAs, in regulating endothelial cellular functions, including nitric oxide production, vascular inflammation, and anti-thromboformation. In this review, how senescent-related miRNAs are involved in controlling the functions of ECs will be discussed.

Inferring potential small molecule-miRNA association based on triple layer heterogeneous network

Recently, many biological experiments have indicated that microRNAs (miRNAs) are a newly discovered small molecule (SM) drug targets that play an important role in the development and progression of human complex diseases. More and more computational models have been developed to identify potential associations between SMs and target miRNAs, which would be a great help for disease therapy and clinical applications for known drugs in the field of medical research. In this study, we proposed a computational model of triple layer heterogeneous network based small molecule–MiRNA association prediction (TLHNSMMA) to uncover potential SM–miRNA associations by integrating integrated SM similarity, integrated miRNA similarity, integrated disease similarity, experimentally verified SM–miRNA associations and miRNA–disease associations into a heterogeneous graph. To evaluate the performance of TLHNSMMA, we implemented global and two types of local leave-one-out cross validation as well as fivefold cross validation to compare TLHNSMMA with one previous classical computational model (SMiR-NBI). As a result, for Dataset 1, TLHNSMMA obtained the AUCs of 0.9859, 0.9845, 0.7645 and 0.9851 ± 0.0012, respectively; for Dataset 2, the AUCs are in turn 0.8149, 0.8244, 0.6057 and 0.8168 ± 0.0022. As the result of case studies shown, among the top 10, 20 and 50 potential SM-related miRNAs, there were 2, 7 and 14 SM–miRNA associations confirmed by experiments, respectively. Therefore, TLHNSMMA could be effectively applied to the prediction of SM–miRNA associations.

Shikonin-mediated up-regulation of miR-34a and miR-202 inhibits retinoblastoma proliferation

Retinoblastoma (RB) is an ocular tumor that occurs mainly in children. The pathogenesis of RB is not well understood, and its treatment strategies are very limited. Shikonin is widely reported as an anti-tumor agent. However, its effect on RB is still unknown. MTT assay was performed to detect the proliferation ability of two RB cell lines, Y-79 and WERI-Rb-1, upon treatment with Shikonin. Colony formation assay was conducted to examine the clonogenic ability of Shikonin-treated cells. Real-time PCR and western blotting were performed for expression analysis of miRNAs and MYCN, respectively. Luciferase activity assay was conducted to test the inhibition mechanism of miR-34a and miR-202 on MYCN. Shikonin could effectively inhibit the proliferation of RB cells and upregulate the expressions of miR-34a and miR-202. MiR-34a and miR-202 could directly target the mRNA degradation of oncogene MYCN, and the inhibitory effect of Shikonin was largely weakened by restoring the MYCN protein expression. Shikonin-mediated up-regulation of miR-34a and miR-202 inhibits RB proliferation, partially mediated through MYCN.

miR-146a induces apoptosis in neuroblastoma cells by targeting BCL11A

Aberrant expression of miR-146a has been reported to be involved in the progression and metastasis of various types of human cancers; however, its potential role in human neuroblastoma is still poorly understood. The purpose of our study was to investigate the molecular mechanism and possible role of miR-146a in human neuroblastoma. In this study, targeted genes were predicted by bioinformatic analysis and confirmed by dual-Luciferase reporter assay. The expression level of miR-146a in the human neuroblastoma SK-N-SH cell line was detected by quantitative RT-PCR. We used flow cytometric analysis to determine apoptosis and necrosis of SK-N-SH cells after transfection with miR-146a inhibitor, miR-146a mimic, and negative controls. The expression level of target genes was detected by RT-PCR and Western blotting. We identified BCL11A as a target of miR-146a. Thus, miR-146a targets the 3'UTR of BCL11A and inhibits its mRNA and protein expression. Overexpression of miR-146a can inhibit the growth and promote the apoptosis of human neuroblastoma SK-N-SH cells through inhibiting the expression of BCL11A. Furthermore, we found that upregulation of BCL11A by miR-146a inhibitor can promote SK-N-SH cells growth and protect SK-N-SH cells against apoptosis. Our results showed that miR-146a is a potential tumor suppressor gene in human neuroblastoma via directly targeting BCL11A. These findings suggest that miR-146a might be a new candidate target for treatment of human neuroblastoma.

Analysis of the microRNA expression profiles in DEF cells infected with duck Tembusu virus

Duck Tembusu virus (DTMUV), belonging to the Flaviviridae family, is a single-stranded positive-sense RNA virus. Since April 2010, the outbreak of DTMUV in southeast provinces of China has caused great economic losses. MicroRNAs (miRNAs) play important regulatory roles in viral infection through binding to the host target genes or the viral genomes. To better understanding the molecular mechanisms of virus-host interaction, here we identified the miRNA expression profiles in DTMUV-infected and uninfected DEF cells by high-throughput sequencing. A total of 287 known and 63 novel miRNAs were identified. 48 miRNAs, including 26 known miRNAs and 22 novel miRNAs, were differentially expressed in response to DTMUV infection. Among these miRNAs, 37 miRNAs were up-regulated and 11 miRNAs were down-regulated. 9 miRNAs were randomly selected for validation by qRT-PCR experiment. The results of qRT-PCR experiment were consistent with the sequencing data. GO enrichment showed that the predicted targets of these differentially expressed miRNAs were mainly involved in the regulation of immune system, cellular process and metabolic process. KEGG pathways analysis showed that predicted target genes were involved in several signaling pathways such as Wnt signaling pathway, TGF-beta signaling pathway, mTOR signaling pathway and FoxO signaling pathway. This is the first study to evaluate changes of miRNA expression in DEF cells upon DTMUV infection. Our findings provide important clues for better understanding the DTMUV-host interaction.

MiR-320a-3p/ELF3 axis regulates cell metastasis and invasion in non-small cell lung cancer via PI3K/Akt pathway

MicroRNAs (miRNAs) play important roles in tumorigenesis and tumor progression. In this study, we investigated the role of miR-320a-3p in non-small cell lung cancer (NSCLC). Expressions of miR-320a-3p were firstly determined in 80 NSCLC patients' cancer tissues and adjacent normal lung tissues by qRT-PCR. Then MTT assay, cell migration and invasion assays were performed in vitro. Potential binding sites on target gene of miR-320a-3p were predicted and luciferase reporter assay was used to identify the potential binding sites. Tumorigenesis assay were performed in nude mice by injecting A549 cells which stably express miR-320a-3p. Results indicated that high expression of miR-320a-3p suppresses cell proliferation, migration and invasion through the inactivation of PI3K/Akt signaling pathway in NSCLC cells. Smaller tumor size and lighter weight were also found in nude mice which had miR-320a-3p higher expressed. Furthermore, data from luciferase reporter assay proved the direct binding of miR-320a-3p on the 3'UTR region of ELF3 mRNA, this could further decrease ELF3 expression transcriptionally. We provided evidence that miR-320a-3p might work as a tumor suppressor in NSCLC both in vivo and in vitro.

Neuroblastoma

Neuroblastoma is one of the most common solid tumors in children and has a diverse clinical behavior that largely depends on the tumor biology. Neuroblastoma exhibits unique features, such as early age of onset, high frequency of metastatic disease at diagnosis in patients over 1 year of age and the tendency for spontaneous regression of tumors in infants. The high-risk tumors frequently have amplification of the MYCN oncogene as well as segmental chromosome alterations with poor survival. Recent advanced genomic sequencing technology has revealed that mutation of ALK, which is present in ~10% of primary tumors, often causes familial neuroblastoma with germline mutation. However, the frequency of gene mutations is relatively small and other aberrations, such as epigenetic abnormalities, have also been proposed. The risk-stratified therapy was introduced by the Japan Neuroblastoma Study Group (JNBSG), which is now moving to the Neuroblastoma Committee of Japan Children's Cancer Group (JCCG). Several clinical studies have facilitated the reduction of therapy for children with low-risk neuroblastoma disease and the significant improvement of cure rates for patients with intermediate-risk as well as high-risk disease. Therapy for patients with high-risk disease includes intensive induction chemotherapy and myeloablative chemotherapy, followed by the treatment of minimal residual disease using differentiation therapy and immunotherapy. The JCCG aims for better cures and long-term quality of life for children with cancer by facilitating new approaches targeting novel driver proteins, genetic pathways and the tumor microenvironment.

Expression of miR-34a in T-Cells Infected by Human T-Lymphotropic Virus 1

Human T-lymphotropic virus 1 (HTLV-1) immortalizes T-cells and is the causative agent of adult T-cell leukemia/lymphoma (ATLL). HTLV-1 replication and transformation are governed by multiple interactions between viral regulatory proteins and host cell factors that remain to be fully elucidated. The present study investigated the impact of HTLV-1 infection on the expression of miR-34a, a microRNA whose expression is downregulated in many types of cancer. Results of RT-PCR assays showed that five out of six HTLV-1-positive cell lines expressed higher levels of miR-34a compared to normal PBMC or purified CD4+ T-cells. ATLL cell line ED, which did not express miR-34a, showed methylation of the miR-34a promoter. Newly infected PBMC and samples from 10 ATLL patients also showed a prominent increase in miR-34a expression compared to PBMC controls. The primary miR-34a transcript expressed in infected cell line C91PL contained binding motifs for NF-κB and p53. Pharmacological inhibition of NF-κB with Bay 11-7082 indicated that this pathway contributes to sustain miR-34a levels in infected cells. Treatment of infected cell lines with the p53 activator nutlin-3a resulted in a further increase in miR-34a levels, thus confirming it as a transcriptional target of p53. Nutlin-3a-treated cells showed downregulation of known miR-34a targets including the deacetylase SIRT1, which was accompanied by increased acetylation of p53, a substrate of SIRT1. Transfection of C91PL cells with a miR-34a mimic also led to downregulation of mRNA targets including SIRT1 as well as the pro-apoptotic factor BAX. Unlike nutlin-3a, the miR-34a mimic did not cause cell cycle arrest or reduce cell viability. On the other hand, sequestration of miR-34a with a sponge construct resulted in an increase in death of C91PL cells. These findings provide evidence for a functional role for miR-34a in fine-tuning the expression of target genes that influence the turnover of HTLV-1-infected cells.

Improved sensitivity for detection of breast cancer by combination of miR-34a and tumor markers CA 15-3 or CEA

Background

MicroRNAs biomarkers have shown value for diagnosis and prognosis of various cancers. Combination with established tumor markers has rarely been done.

Results

Breast cancer patients had significantly higher serum RNA loads (AUC 0.665), lower miR-34a (AUC 0.772), higher CEA and CA 15-3 levels (AUCs 0.717 and 0.721) than healthy controls. miR-34a correlated with tumor stage and hormone receptor status. There was no significant difference between groups for all other miRNAs. Combination of miR-34a with CEA or CA 15-3 led to improved AUCs of 0.844 and 0.800, respectively. Sensitivity of miR-34a and CA 15-3 reached 56.1% at 95% specificity. When compared with benign breast diseases, combination of miR-34a (AUC 0.719) and CEA (0.623) or CA 15-3 (0.619) resulted in improved performances (0.794 and 0.741). Sensitivity of miR-34a and CA 15-3 reached 53.7% at 95% specificity.

Conclusion

While miR-34a provides valuable information for diagnosis and staging, combination with tumor markers CA15-3 or CEA improves the sensitivity for breast cancer detection.

Patients and Methods

The diagnostic relevance of the miR-21, miR-34a, miR-92a, miR-155, miR-222 and miR-let-7c was tested in sera of 103 individuals (55 breast cancer, 20 benign breast diseases, 28 healthy controls). MiRNAs were detected by quantitative rt-PCR after extraction and reverse transcription. Cel-miR-39 and miR-16 were used for normalization. Established tumor markers CEA, CA 15-3, CA 19-9 and CA 125 were measured by automatized immunoassays. Diagnostic performance was tested by areas under the curve (AUC) of receiver operating characteristic (ROC) curves and sensitivities at 90% and 95% specificity.

MicroRNA-193b-3p represses neuroblastoma cell growth via downregulation of Cyclin D1, MCL-1 and MYCN

Neuroblastoma is the most common diagnosed tumor in infants and the second most common extracranial tumor of childhood. The survival rate of patients with high-risk neuroblastoma is still very low despite intensive multimodal treatments. Therefore, new treatment strategies are needed. In recent years, miRNA-based anticancer therapy has received growing attention. Advances in this novel treatment strategy strongly depends on the identification of candidate miRNAs with broad-spectrum antitumor activity. Here, we identify miR-193b as a miRNA with tumor suppressive properties. We show that miR-193b is expressed at low levels in neuroblastoma cell lines and primary tumor samples. Introduction of miR-193b mimics into nine neuroblastoma cell lines with distinct genetic characteristics significantly reduces cell growth in vitro independent of risk factors such as p53 functionality or MYCN amplification. Functionally, miR-193b induces a G1 cell cycle arrest and cell death in neuroblastoma cell lines by reducing the expression of MYCN, Cyclin D1 and MCL-1, three important oncogenes in neuroblastoma of which inhibition has shown promising results in preclinical testing. Therefore, we suggest that miR-193b may represent a new candidate for miRNA-based anticancer therapy in neuroblastoma.

Micro-Economics of Apoptosis in Cancer: ncRNAs Modulation of BCL-2 Family Members

In the last few years, non-coding RNAs (ncRNAs) have been a hot topic in cancer research. Many ncRNAs were found to regulate the apoptotic process and to play a role in tumor cell resistance to treatment. The apoptotic program is on the frontline as self-defense from cancer onset, and evasion of apoptosis has been classified as one of the hallmarks of cancer responsible for therapy failure. The B-cell lymphoma 2 (BCL-2) family members are key players in the regulation of apoptosis and mediate the activation of the mitochondrial death machinery in response to radiation, chemotherapeutic agents and many targeted therapeutics. The balance between the pro-survival and the pro-apoptotic BCL-2 proteins is strictly controlled by ncRNAs. Here, we highlight the most common mechanisms exerted by microRNAs, long non-coding RNAs and circular RNAs on the main mediators of the intrinsic apoptotic cascade with particular focus on their significance in cancer biology.

MicroRNA-34a regulates proliferation and apoptosis of gastric cancer cells by targeting silent information regulator 1

The present study aimed to identify whether microRNA (miRNA/miR)-34a regulates the proliferation and apoptosis of gastric cancer cells by targeting silent information regulator 1 (SIRT1). The expression of miR-34a and SIRT1 and cell viability was investigated in gastric cancer cells. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was applied to determine miR-34a expression in gastric adenocarcinoma, normal pericarcinomatous tissues, human normal gastric mucosa epithelial cell line GES and various gastric cancer cell strains. A bioinformatics method was then used to predict the target gene of miR-34a. A human miR-34a over expression lentiviral vector system was constructed and then used for transfection of the gastric cancer cell line SCG-7901 to determine the expression of SIRT1 mRNA and SIRT1 protein using RT-qPCR and western blot analysis. The MTT method and flow cytometry was used to measure cell proliferation and apoptosis. The relative expression of miR-34a in gastric cancer tissues was significantly decreased compared with that in normal tissues (P<0.01). miR-34a expression was also significantly decreased in low differentiated N2, N3 gastric cancer tissues (P<0.01). However, tumor size and filtration degree were not significantly associated with miR-34a expression. The relative expression of miR-34a was decreased in gastric cancer cells, especially in the SGC-7901 cell line (P<0.01) compared with the GES group. The relative expression of SIRT1 protein was decreased in the miR-34a group compared with the negative control (P<0.01). The rate of proliferation was significantly decreased, whereas the rate of apoptosis was significantly increased in the miR-34a group compared with the NC group (P<0.01). Therefore, the present results suggested that miRNA-34a serves a pivotal role in gastric cancer as a cancer suppressor gene by targeting SIRT1 to regulate the proliferation and apoptosis of gastric cancer cells.

Altered expression of miRNAs and methylation of their promoters are correlated in neuroblastoma

Neuroblastoma is the most common human extracranial solid tumor during infancy. Involvement of several miRNAs in its pathogenesis has been ascertained. Interestingly, most of their encoding genes reside in hypermethylated genomic regions: thus, their tumor suppressor function is normally disallowed in these tumors. To date, the therapeutic role of the demethylating agent 5′-Aza-2 deoxycytidine (5'-AZA) and its effects on miRNAome modulation in neuroblastoma have not been satisfactorily explored. Starting from a high-throughput expression profiling of 754 miRNAs and based on a proper selection, we focused on miR-29a-3p, miR-34b-3p, miR-181c-5p and miR-517a-3p as candidate miRNAs for our analysis. They resulted downregulated in four neuroblastoma cell lines with respect to normal adrenal gland. MiRNAs 29a-3p and 34b-3p also resulted downregulated in vivo in a murine neuroblastoma progression model. Unlike the amount of methylation of their encoding gene promoters, all these miRNAs were significantly overexpressed following treatment with 5′-AZA. Transfection with candidate miRNAs mimics significantly decreased neuroblastoma cells proliferation rate. A lower expression of miR-181c was significantly associated to a worse overall survival in a public dataset of 498 neuroblastoma samples (http://r2.amc.nl). Our data strongly suggest that CDK6, DNMT3A, DNMT3B are targets of miR-29a-3p, while CCNE2 and E2F3 are targets of miR-34b-3p. Based on all these data, we propose that miR-29a-3p, miR-34b-3p, miR-181c-5p and miR-517a-3p are disallowed tumor suppressor genes in neuroblastoma and suggest them as new therapeutic targets in neuroblastoma.

Triptolide Inhibits Proliferation and Migration of Human Neuroblastoma SH-SY5Y Cells by Upregulating MicroRNA-181a

Neuroblastoma is the primary cause of cancer-related death for children 1 to 5 years of age. New therapeutic strategies and medicines are urgently needed. This study aimed to investigate the effects of triptolide (TPL), the major active component purified from Tripterygium wilfordii Hook F, on neuroblastoma SH-SY5Y cell proliferation, migration, and apoptosis, as well as underlying potential mechanisms. We found that TPL inhibited SH-SY5Y cell viability, proliferation, and migration, but induced cell apoptosis. The expression of matrix metalloproteinase-2 (MMP-2) and MMP-9 after TPL treatment in SH-SY5Y cells was decreased. The expression of microRNA-181a (miR-181a) was upregulated after TPL treatment. Moreover, suppression of miR-181a reversed the effects of TPL on SH-SY5Y cell proliferation, apoptosis, and migration. Overexpression of miR-181a enhanced the TPL-induced activation of p38 mitogen-activated protein kinase (p38MAPK) and nuclear factor κ light chain enhancer of activated B cells (NF-κB) pathways. In conclusion, our research verified that TPL inhibited the proliferation and migration of human neuroblastoma SH-SY5Y cells by upregulating the expression of miR-181a.

MicroRNA-383 upregulation protects against propofol-induced hippocampal neuron apoptosis and cognitive impairment

Anesthesia-induced cognitive impairment is a recognized clinical phenomenon. The present study aimed to investigate the effect of microRNA-383 (miR-383) expression on propofol-induced learning and memory impairment. In total, 48 male Sprague-Dawley rats (weight, 250±10 g) were randomly divided into four groups (n=12 each): Control group, and three groups of rats that were anesthetized with propofol for 6 h and untreated (propofol model group), treated with a constructed lentivirus vector expressing miR-383 mimics (mimic + propofol group), or treated with miR-383 scramble (scramble + propofol group). The learning memory ability, hippocampal neuron apoptosis and expression of apoptosis-associated factors were detected using reverse transcription-quantitiative polymerase chain reaction and western blot analysis. Propofol treatment significantly reduced the relative mRNA and protein expression of miR-383, induced neuron apoptosis, upregulated the Bax/Bcl-2 ratio, downregulated the relative mRNA and protein expression levels of postsynaptic density protein 95 and cAMP-response element binding protein, and inactivated the phosphoinositide 3-kinase/protein kinase B signaling pathway. By contrast, miR-383 mimics significantly altered the propofol-induced dysregulation of the aforementioned factors. In conclusion, miR-383 mimic was able to repair propofol-induced cognitive impairment via protecting against hippocampal neuron apoptosis and dysregulation of related factors. The present study suggested that miR-383 may be used as a potential therapeutic target for the clinical treatment of cognitive impairment induced by propofol anesthesia.

miR-34a is involved in CSE-induced apoptosis of human pulmonary microvascular endothelial cells by targeting Notch-1 receptor protein

Background

Abnormal apoptosis of lung endothelial cells has been observed in emphysematous lung tissue and has been suggested to be an important upstream event in the pathogenesis of chronic obstructive pulmonary disease (COPD). Studies have shown that microRNAs (miRNAs) contribute to the pathogenesis of pulmonary diseases by regulating cell apoptosis. The present study was designed to investigate the expression of microRNA-34a (miR-34a) in human pulmonary microvascular endothelial cells (HPMECs) exposed to cigarette smoke extract (CSE), and the potential regulatory role of miR-34a in endothelial cell apoptosis.

Results

Our results showed that the expression of miR-34a was significantly increased in CSE-treated HPMECs, and inhibiting miR-34a attenuated CSE-induced HPMEC apoptosis. Furthermore, expression of Notch-1, a receptor protein in the Notch signalling pathway, was decreased and was inversely correlated with miR-34a expression in HPMECs treated with CSE. Computational miRNA target prediction confirmed that Notch-1 is a target of miR-34a. Luciferase reporter assay further confirmed the direct interaction between miR-34a and the 3’-untranslated region (UTR) of Notch-1. Restoration of Notch-1 pathway was able to partially block the effect of miR-34a on HPMEC apoptosis. These results indicate that Notch-1 is a critical downstream target of miR-34a in regulating the CSE-induced HPMEC apoptosis.

Conclusions

Our results suggest that miR-34a plays a key role in CSE-induced endothelial cell apoptosis by directly regulating its target gene Notch-1 in endothelial cells.

Multi-Functional Peptide-MicroRNA Nanocomplex for Targeted MicroRNA Delivery and Function Imaging

Targeted delivery of microRNA (miRNA) mimics into specific cells/tissues and real-time monitoring on the biological function of delivered miRNA mimics at molecular level represent two major challenges in the development of miRNA-based therapeutics. Here we report a highly efficient method to address these two challenges simultaneously by using the self-assembled nanocomplex formed by miRNA mimics with a multi-functional peptide conjugate. Using the nanocomplex formed by tumor-suppressive miR-34a and the multi-functional peptide conjugate FA-R9-FP_cas3 , we demonstrated the highly efficient and target-selective delivery of miR-34a into HeLa cells and tumors. With the activatable fluorescence probe integrated in the peptide conjugate FA-R9-FP_cas3 , the intracellular function of miR-34a delivered by the nanocomplex to upregulate active Caspase-3 was imaged in real-time. The nanocomplex also showed significant therapeutic effects to induce apoptosis in HeLa cells and to suppress tumor growth upon tail vein injection into living mice bearing subcutaneous HeLa tumors.

MiRNA Influences in Neuroblast Modulation: An Introspective Analysis

Neuroblastoma (NB) is the most common occurring solid paediatric cancer in children under the age of five years. Whether of familial or sporadic origin, chromosome abnormalities contribute to the development of NB and cause dysregulation of microRNAs (miRNAs). MiRNAs are small non-coding, single stranded RNAs that target messenger RNAs at the post-transcriptional levels by repressing translation within all facets of human physiology. Such gene 'silencing' activities by miRNAs allows the development of regulatory feedback loops affecting multiple functions within the cell, including the possible differentiation of neural stem cell (NSC) lineage selection. Neurogenesis includes stages of self-renewal and fate specification of NSCs, migration and maturation of young neurones, and functional integration of new neurones into the neural circuitry, all of which are regulated by miRNAs. The role of miRNAs and their interaction in cellular processes are recognised aspects of cancer genetics, and miRNAs are currently employed as biomarkers for prognosis and tumour characterisation in multiple cancer models. Consequently, thorough understanding of the mechanisms of how these miRNAs interplay at the transcriptomic level will definitely lead to the development of novel, bespoke and efficient therapeutic measures, with this review focusing on the influences of miRNAs on neuroblast modulations leading to neuroblastoma.

Inhibition of miR‑34a prevents endothelial cell apoptosis by directly targeting HDAC1 in the setting of atherosclerosis

Despite recent medical advances, atherosclerosis is a global burden accounting for numerous mortalities and hospital admissions. MicroRNAs (miRNAs/miRs) regulate cardiovascular biology and disease, but the role of microRNA‑34a in atherosclerosis remains unclear. In the present study, it was demonstrated that miR‑34a was highly expressed in atherosclerotic lesions and oxidized low‑density lipoprotein (Ox‑LDL)‑treated human aortic endothelial cells (HAECs) (atherosclerotic cell model) using reverse transcription‑quantitative polymerase chain reaction. The expression of histone deacetylase (HDAC) 1 was reduced in atherosclerotic lesions and Ox‑LDL treated HAECs. TargetScan predicted that HDAC1 is the potential target of miR‑34a and the double‑luciferase reporter assay confirmed that HDAC1 was directly targeted by miR‑34a. Furthermore, miR‑34a inhibitor significantly enhanced the cell viability of HAECs and the cell apoptosis was suppressed. In addition, the expression of apoptotic‑related proteins was detected by western blotting. The results showed that miR‑34a inhibitor significantly upregulated B‑cell lymphoma 2, procaspase‑3, procaspase‑9 and proto‑oncogene c‑Myc protein expression, and downregulated the expression of p21. In contrast, co‑transfection of HDAC1‑small interfering RNA and miR‑34a inhibitor eliminated the effects of miR‑34a on HAECs. This indicated that miR‑34a inhibitor promoted cell viability and prevented cell apoptosis of HAECs through regulating HDAC1. In conclusion, it was demonstrated that miR‑34a promoted atherosclerotic formation by modulating the proliferation and apoptosis of HAECs, and regulating the expression of apoptosis‑related proteins by targeting HDAC1.

The dawn of the liquid biopsy in the fight against cancer

Cancer is a molecular disease associated with alterations in the genome, which, thanks to the highly improved sensitivity of mutation detection techniques, can be identified in cell-free DNA (cfDNA) circulating in blood, a method also called liquid biopsy. This is a non-invasive alternative to surgical biopsy and has the potential of revealing the molecular signature of tumors to aid in the individualization of treatments. In this review, we focus on cfDNA analysis, its advantages, and clinical applications employing genomic tools (NGS and dPCR) particularly in the field of oncology, and highlight its valuable contributions to early detection, prognosis, and prediction of treatment response.

Design and implementation of a synthetic pre-miR switch for controlling miRNA biogenesis in mammals

Synthetic RNA-based systems have increasingly been used for the regulation of eukaryotic gene expression. Due to their structural properties, riboregulators provide a convenient basis for the development of ligand-dependent controllable systems. Here, we demonstrate reversible conditional control of miRNA biogenesis with an aptamer domain as a sensing unit connected to a natural miRNA precursor for the first time. For the design of the pre-miR switch, we replaced the natural terminal loop with the TetR aptamer. Thus, the TetR aptamer was positioned close to the Dicer cleavage sites, which allowed sterical control over pre-miR processing by Dicer. Our design proved to be highly versatile, allowing us to regulate the biogenesis of three structurally different miRNAs: miR-126, -34a and -199a. Dicer cleavage was inhibited up to 143-fold via co-expression of the TetR protein, yet could be completely restored upon addition of doxycycline. Moreover, we showed the functionality of the pre-miR switches for gene regulation through the interaction of the respective miRNA with its specific target sequence. Our designed device is capable of robust and reversible control of miRNA abundance. Thus, we offer a novel investigational tool for functional miRNA analysis.

miR-34b Modulates Skeletal Muscle Cell Proliferation and Differentiation

Myogenesis involves myoblast proliferation and differentiation to myocytes, followed by fusion and hypertrophy to form myotubes during muscle development. Increasing evidence showed that microRNAs (miRNAs) play important roles in the regulation of myogenesis. We have previously revealed that miR-34b is steadily increased during this process. This miRNA regulates differentiation in various cell types, though its function in myogenesis remains to be elucidated. In this study, we show that miR-34b represses muscle cell proliferation and promotes myotube formation. Our quantitative iTRAQ-based proteomic analysis reveals 97 proteins are regulated by miR-34b in mouse myoblast C2C12. We identified that miR-34b targets 14-3-3 protein gamma, adenosylhomocysteinase and nucleolin by binding to their 3'UTR. Further analysis of these proteins expression patterns show that nucleolin is a cognate target of miR-34b during myogenic differentiation. Here, we proved that a moderate reduction of nucleolin in cells enhanced the myotube formation. However, nucleolin is required for myogenesis, as cells with low levels of nucleolin reduced cell proliferation rate and are unable to differentiate. Our data demonstrated that nucleolin regulates myogenesis in a protein-abundance-dependent manner. J. Cell. Biochem. 118: 4285-4295, 2017. © 2017 Wiley Periodicals, Inc.

PD-L1, inflammation, non-coding RNAs, and neuroblastoma: Immuno-oncology perspective

Neuroblastoma is the most common pediatric solid tumor of neural crest origin. The current treatment options for neuroblastoma produce severe side effects. Programmed death-ligand 1 (PD-L1), chronic inflammation, and non-coding RNAs are known to play a significant role in the pathogenesis of neuroblastoma. Cancer cells and the surrounding cells in the tumor microenvironment express PD-L1. Programmed death-1 (PD-1) is a co-receptor expressed predominantly by T cells. The binding of PD-1 to its ligands, PD-L1 or PD-L2, is vital for the physiologic regulation of the immune system. Chronic inflammation is involved in the recruitment of leukocytes, production of cytokines and chemokines that in turn, lead to survival, metastasis, and angiogenesis in neuroblastoma tumors. The miRNAs and long non-coding (lnc) RNAs have emerged as a novel class of non-coding RNAs that can regulate neuroblastoma associated cell-signaling pathways. The dysregulation of PD-1/PD-L1, inflammatory pathways, lncRNAs, and miRNAs have been reported in clinical and experimental samples of neuroblastoma. These signaling molecules are currently being evaluated for their potential as the biomarker and therapeutic targets in the management of neuroblastoma. A monoclonal antibody called dinutuximab (Unituxin) that attaches to a carbohydrate molecule GD2, on the surface of many neuroblastoma cells, is being used as an immunotherapy drug for neuroblastoma treatment. Atezolizumab (Tecentriq), an engineered monoclonal antibody against PD-L1, are currently in clinical trial for neuroblastoma patients. The lncRNA/miRNA-based therapeutics is being developed to deliver tumor suppressor lncRNAs/miRNAs or silencing of oncogenic lncRNAs/miRNAs. The focus of this review is to discuss the current knowledge on the immune checkpoint molecules, PD-1/PD-L1 signaling, inflammation, and non-coding RNAs in neuroblastoma.

MicroRNA-target cross-talks: Key players in glioblastoma multiforme

The role of microRNAs in brain cancer is still naive. Some act as oncogene and others as tumor suppressors. Discovery of efficient biomarkers is mandatory to debate that aggressive disease. Bioinformatically selected microRNAs and their targets were investigated to evaluate their putative signature as diagnostic and prognostic biomarkers in primary glioblastoma multiforme. Expression of a panel of seven microRNAs (hsa-miR-34a, hsa-miR-16, hsa-miR-17, hsa-miR-21, hsa-miR-221, hsa-miR-326, and hsa-miR-375) and seven target genes ( E2F3, PI3KCA, TOM34, WNT5A, PDCD4, DFFA, and EGFR) in 43 glioblastoma multiforme specimens were profiled compared to non-cancer tissues via quantitative reverse transcription-polymerase chain reaction. Immunohistochemistry staining for three proteins (VEGFA, BAX, and BCL2) was performed. Gene enrichment analysis identified the biological regulatory functions of the gene panel in glioma pathway. MGMT ( O-6-methylguanine-DNA methyltransferase) promoter methylation was analyzed for molecular subtyping of tumor specimens. Our data demonstrated a significant upregulation of five microRNAs (hsa-miR-16, hsa-miR-17, hsa-miR-21, hsa-miR-221, and hsa-miR-375), three genes ( E2F3, PI3KCA, and Wnt5a), two proteins (VEGFA and BCL2), and downregulation of hsa-miR-34a and three other genes ( DFFA, PDCD4, and EGFR) in brain cancer tissues. Receiver operating characteristic analysis revealed that miR-34a (area under the curve = 0.927) and miR-17 (area under the curve = 0.900) had the highest diagnostic performance, followed by miR-221 (area under the curve = 0.845), miR-21 (area under the curve = 0.836), WNT5A (area under the curve = 0.809), PDCD4 (area under the curve = 0.809), and PI3KCA (area under the curve = 0.800). MGMT promoter methylation status was associated with high miR-221 levels. Moreover, patients with VEGFA overexpression and downregulation of TOM34 and BAX had poor overall survival. Nevertheless, miR-17, miR-221, and miR-326 downregulation were significantly associated with high recurrence rate. Multivariate analysis by hierarchical clustering classified patients into four distinct groups based on gene panel signature. In conclusion, the explored microRNA-target dysregulation could pave the road toward developing potential therapeutic strategies for glioblastoma multiforme. Future translational and functional studies are highly recommended to better understand the complex bio-molecular signature of this difficult-to-treat tumor.

MicroRNA profiles in neuroblastoma: Differences in risk and histology groups

AIM

To determine the miRNA expression profiles of neuroblastomas with different clinical and histological characteristics.

METHODS

In this study 24 samples from 17 patients, paraffin blocks were used. Their microRNA profiles were compared by five different analysis: analysis I: well-poorly differentiated, analysis II: before-after chemotherapy, analysis III: favorable-unfavorable histology, analysis IV: neuroblastoma-ganglioneuroma, analysis V: low-risk-middle-risk-high risk groups. Clinical data were compared with differentially expressed microRNAs.

RESULTS

It was found that 25 miRNAs between well-poorly differentiated tumors, eight miRNAs before and after of the chemotherapy, three miRNAs between favorable and unfavorable histology, four miRNAs between neuroblastoma and ganglioneuroma, seven miRNAs between low and middle risk, one miRNA between middle and high risk, 14 miRNAs between low and high risk were differently expressed (P < 0.01). These miRNA's targeted mostly the cancer pathway by the KEGG pathway analysis. The most marked difference was seen in miR-132 and miR-490, comparing the clinical data and all microRNAs. The most fold change was detected at miR-98-5p between the tissues of high- and low-risk patients.

CONCLUSION

In this study, we represent microRNA expression profiles of neuroblastoma patients' tissue with different clinical, histological grade, differentiation, and treatment status, and which could be informative for new therapies targeting microRNAs.

Alternative mechanisms of miR-34a regulation in cancer

MicroRNA miR-34a is recognized as a master regulator of tumor suppression. The strategy of miR-34a replacement has been investigated in clinical trials as the first attempt of miRNA application in cancer treatment. However, emerging outcomes promote the re-evaluation of existing knowledge and urge the need for better understanding the complex biological role of miR-34a. The targets of miR-34a encompass numerous regulators of cancer cell proliferation, survival and resistance to therapy. MiR-34a expression is transcriptionally controlled by p53, a crucial tumor suppressor pathway, often disrupted in cancer. Moreover, miR-34a abundance is fine-tuned by context-dependent feedback loops. The function and effects of exogenously delivered or re-expressed miR-34a on the background of defective p53 therefore remain prominent issues in miR-34a based therapy. In this work, we review p53-independent mechanisms regulating the expression of miR-34a. Aside from molecules directly interacting with MIR34A promoter, processes affecting epigenetic regulation and miRNA maturation are discussed. Multiple mechanisms operate in the context of cancer-associated phenomena, such as aberrant oncogene signaling, EMT or inflammation. Since p53-dependent tumor-suppressive mechanisms are disturbed in a substantial proportion of malignancies, we summarize the effects of miR-34a modulation in cell and animal models in the clinically relevant context of disrupted or insufficient p53 function.

The expression of microRNA-324-3p as a tumor suppressor in nasopharyngeal carcinoma and its clinical significance

Objective

This study aimed to determine the expression, clinical significance, and possible biologic function of microRNA-324-3p in nasopharyngeal carcinoma (NPC) tissues.

Methods

In total, 54 NPC and 35 control tissues were collected. The correlation between miR-324-3p expression and the clinicopathologic characteristics was analyzed. A dual-luciferase reporter gene assay was employed to examine the predicted target gene of miR-324-3p. The miR-324-3p expression level in 5–8F cells was determined with quantitative reverse transcription-polymerase chain reaction following the transfection of miR-324-3p mimics and inhibitors. Cell proliferation and the percentage of apoptosis were measured with MTT and flow cytometry. Cell invasion ability was assessed by Transwell invasion assay.

Results

Our results showed that miR-324-3p was downregulated in the NPC tissues. The expression level of miR-324-3p in poorly differentiated NPC was significantly reduced in comparison with that in well/moderately differentiated NPC. The expression level in clinical stages III/IV was lower than that in clinical stages I/II. Moreover, the expression level of miR-324-3p was significantly lower in NPC patients with lymph node metastasis than that in NPC patients without lymph node metastasis. NPC patients with higher levels of miR-324-3p expression also demonstrated a longer survival time. Predictions from bioinformatics indicated the Hedgehog pathway transcription gene GLI3 as the target gene of miR-324-3p, and the dual- luciferase reporter assay showed that miR-324-3p is directly combined with the 3′-untranslated region of GLI3. The overexpression of miR-324-3p suppressed cell proliferation and invasion, and it enhanced apoptosis in 5–8F cells.

Conclusion

miR-324-3p can act as a tumor suppressor in NPC cells by the negative regula- tion of GLI3 gene.

The roles of microRNA-34b-5p in angiogenesis of thyroid carcinoma

PURPOSE

This study aims to determine the expression of miR-34b-5p in thyroid carcinomas and to investigate the role of miR34b-5p in the modulation of proteins involved in angiogenesis of thyroid carcinoma cells.

METHODS

The expressions of miR-34b-5p levels in five cell lines and 65 tissue samples from thyroid carcinomas were examined by real-time polymerase chain reaction. An exogenous miR-34b-5p (mimic) transiently overexpress miR-34b-5p in theses thyroid carcinoma cells. The effects of miR-34b-5p overexpression on the proteins involved in angiogenesis and cell cycle regulations (VEGF-A, Bcl-2 and Notch1) were investigated by Western blot, immunofluorescence, enzyme-linked immunosorbent assay followed by cell cycle analysis and apoptosis assays.

RESULTS

miR-34b-5p is markedly downregulated in all thyroid carcinoma cell lines and tissues samples when compared with non-neoplastic immortalised thyroid cell line and non-neoplastic thyroid tissues, respectively. The expression levels of miR-34b were significantly associated with T-stages of thyroid carcinomas (p = 0.042). Downregulation of VEGF-A, Bcl-2 and Notch1 proteins in thyroid carcinoma cells were noted in cells that transiently transfected with miR-34b-5p mimic. In addition, enzyme-linked immunosorbent assay confirmed the decreased expression of VEGF in thyroid carcinoma cells after transfection with miR-34b-5p mimic. Furthermore, miR-34b-5p mimic transfection induces significant accumulation of cells in G0-G1 of the cell cycle by blocking of their entry into the S transitional phase as well as increasing the total apoptosis.

CONCLUSIONS

miR-34b-5p functions as a potent regulator of angiogenesis, apoptosis and cell proliferation via modulation of VEGF-A, Bcl-2 and Notch1 proteins. It could be a target for developing treatment strategies of thyroid carcinoma with aggressive clinical behaviour.

microRNA-34a overexpression inhibits cell migration and invasion via regulating SIRT1 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains one of the most common types of malignancy with high mortality and morbidity rates. Previous studies have suggested that microRNAs (miRs) serve pivotal functions in various types of tumor. The aim of the present study was to assess the association between miR-34a expression and HCC cell migration and invasion, and the potential underlying mechanisms. The miR-34a overexpression vector or scramble control was transfected into human Hep3B and Huh7 cell lines. Transwell assays, and Matrigel and wound healing assays were used to detect the effects of miR-34a expression on HCC cell invasion and migration, respectively. The expression of miR-34a and the mRNA expression of other associated proteins were detected using quantitative reverse transcription polymerase chain reaction, and protein levels were measured using western blot analysis. Compared with the control, miR-34a expression was significantly downregulated in Hep3B and Huh7 cells, but this was reversed by the transfection with exogenous miR-34a (P<0.01). The number of migrated or invaded cells was significantly reduced by the overexpression of miR-34a in Hep3B or Huh7 cells (P<0.01). The expression of sirtuin 1 was upregulated, while the level of acetylate-p53 was downregulated by overexpression of miR-34a. Taken together, the results of the present study suggested that the overexpression of miR-34a may have suppressed HCC metastasis via inhibited cell migration and invasion.

Deregulation of miR-34a and Its Chaperon Hsp70 in Hepatitis C virus-Induced Liver Cirrhosis and Hepatocellular Carcinoma Patients

Background: MicroRNA deregulation may occur during hepatocellular carcinoma (HCC) genesis and progression stages. MicroRNA-34a (miR-34a) functions as a tumor suppressor and is down-regulated or silenced in a variety of human cancers, while heat shock proteins (Hsps) play important roles in assisting protein folding and preventing both protein aggregation and transport across membranes. The present study aimed to evaluating serum expression of miR-34a and its target Hsp70 for early detection of HCC in patients with liver cirrhosis (LC), focusing on correlations with clinicopathological features. Methods: A total of 180 patients were included: 120 with HCC on top of LC (60 with either early or late HCC) and 60 patients with HCV-related LC. In addition, 60 healthy individuals were considered as controls. Real-time polymerase chain reactions were performed for expression profiling of serum miR-34a and Hsp70 and for allelic discrimination of the promotor variant (rs2763979, C/T). In addition, in silico analysis was carried out. Results: All participants were heterozygote for the promotor polymorphism. miR-34a serum levels were significantly under-expressed in LC and especially HCC patients as compared to controls. Associations with a high Child-Turcotte- Pugh (CTP) score, advanced cancer stage, and number of masses were noted. In contrast the target Hsp70 was significantly overexpressed in cancer patients but not in LC group and inversely correlated with miR-34a levels. Conclusion: Utility of circulating miRNAs as biomarkers for early detection of HCC was raised. Future large-scale studies are warranted to confirm the current findings.

MicroRNA-34a: A Key Regulator in the Hallmarks of Renal Cell Carcinoma

Renal cell carcinoma (RCC) incidence has increased over the past two decades. Recent studies reported microRNAs as promising biomarkers for early cancer detection, accurate prognosis, and molecular targets for future treatment. This study aimed to evaluate the expression levels of miR-34a and 11 of its bioinformatically selected target genes and proteins to test their potential dysregulation in RCC. Quantitative real-time PCR for miR-34a and its targets; MET oncogene; gene-regulating apoptosis (TP53INP2 and DFFA); cell proliferation (E2F3); and cell differentiation (SOX2 and TGFB3) as well as immunohistochemical assay for VEGFA, TP53, Bcl2, TGFB1, and Ki67 protein expression have been performed in 85 FFPE RCC tumor specimens. Clinicopathological parameter correlation and in silico network analysis have also implicated. We found RCC tissues displayed significantly higher miR-34a expression level than their corresponding noncancerous tissues, particularly in chromophobic subtype. MET and E2F3 were significantly upregulated, while TP53INP2 and SOX2 were downregulated. ROC analysis showed high diagnostic performance of miR-34a (AUC = 0.854), MET (AUC = 0.765), and E2F3 (AUC = 0.761). The advanced pathological grade was associated with strong TGFB1, VEGFA, and Ki67 protein expression and absent Tp53 staining. These findings indicate miR-34a along with its putative target genes could play a role in RCC tumorigenesis and progression.

Cell cycle-targeting microRNAs promote differentiation by enforcing cell-cycle exit

MicroRNAs (miRNAs) have been known to affect various biological processes by repressing expression of specific genes. Here we describe an essential function of the miR-34/449 family during differentiation of epithelial cells. We found that miR-34/449 suppresses the cell-cycle machinery in vivo and promotes cell-cycle exit, thereby allowing epithelial cell differentiation. Constitutive ablation of all six members of this miRNA family causes derepression of multiple cell cycle-promoting proteins, thereby preventing epithelial cells from exiting the cell cycle and entering a quiescent state. As a result, formation of motile multicilia is strongly inhibited in several tissues such as the respiratory epithelium and the fallopian tube. Consequently, mice lacking miR-34/449 display infertility as well as severe chronic airway disease leading to postnatal death. These results demonstrate that miRNA-mediated repression of the cell cycle is required to allow epithelial cell differentiation.

MicroRNA-34a induces transdifferentiation of glioma stem cells into vascular endothelial cells by targeting Notch pathway

The function of microRNA-34a (miR-34a) in transdifferentiation of glioma stem cells (GSCs) into vascular endothelial cells (VECs) was explored by focusing on Notch ligand Delta-like 1 (Dll1). MiR-34a mimics was transfected into CD133 + glioma cell U251. The angiogenesis feature of miR-34a transfected U251 cells was investigated and the expressions of CD31, CD34, Vwf, Notch 1, and Dll1 were quantified. Length of branching vessel-like structures in the miR-34a transfected U251 cells was significantly higher than control cells. The VEC feature of miR-34a overexpressed U251 cells was further confirmed by the expressions of CD31, CD34, and vWF. Transfection of miR-34a decreased the expression of Notch 1 and Dll1. Furthermore, the miR-34a overexpression-enhanced tube formation of GSCs was suppressed when the decreased expression of Dll1 was restored. The current study highlighted the potential of miR-34a as an inducer in GSCs' transdifferentiation into VECs by targeting Dll1.

Quercetin-mediated synthesis of graphene oxide-silver nanoparticle nanocomposites: a suitable alternative nanotherapy for neuroblastoma

Background

Graphene and graphene-related materials have gained substantial interest from both academia and industry for the development of unique nanomaterials for biomedical applications. Graphene oxide (GO) and silver nanoparticles (AgNPs) are a valuable platform for the development of nanocomposites, permitting the combination of nanomaterials with different physical and chemical properties to generate novel materials with improved and effective functionalities in a single platform. Therefore, this study was conducted to synthesize a graphene oxide–silver nanoparticle (GO-AgNPs) nanocomposite using the biomolecule quercetin and evaluate the potential cytotoxicity and mechanism of GO-AgNPs in human neuroblastoma cancer cells (SH-SY5Y).

Methods

The synthesized GO-AgNPs were characterized using various analytical techniques. The potential toxicities of GO-AgNPs were evaluated using a series of biochemical and cellular assays. The expression of apoptotic and anti-apoptotic genes was measured by quantitative real-time reverse transcription polymerase chain reaction. Further, apoptosis was confirmed by caspase-9/3 activity and a terminal deoxynucleotidyl transferase dUTP nick end labeling assay, and GO-AgNPs-induced autophagy was also confirmed by transmission electron microscopy.

Results

The prepared GO-AgNPs exhibited significantly higher cytotoxicity toward SH-SY5Y cells than GO. GO-AgNPs induced significant cytotoxicity in SH-SY5Y cells by the loss of cell viability, inhibition of cell proliferation, increased leakage of lactate dehydrogenase, decreased level of mitochondrial membrane potential, reduced numbers of mitochondria, enhanced level of reactive oxygen species generation, increased expression of pro-apoptotic genes, and decreased expression of anti-apoptotic genes. GO-AgNPs induced caspase-9/3-dependent apoptosis via DNA fragmentation. Finally, GO-AgNPs induced accumulation of autophagosomes and autophagic vacuoles.

Conclusion

In this study, we developed an environmentally friendly, facile, dependable, and simple method for the synthesis of GO-AgNPs nanocomposites using quercetin. The synthesized GO-AgNPs exhibited enhanced cytotoxicity compared with that of GO at very low concentrations. This study not only elucidates the potential cytotoxicity against neuroblastoma cancer cells, but also reveals the molecular mechanism of toxicity.

Identification of Four Oxidative Stress-Responsive MicroRNAs, miR-34a-5p, miR-1915-3p, miR-638, and miR-150-3p, in Hepatocellular Carcinoma

Increasing evidence suggests that oxidative stress plays an essential role during carcinogenesis. However, the underlying mechanism between oxidative stress and carcinogenesis remains unknown. Recently, microRNAs (miRNAs) are revealed to be involved in oxidative stress response and carcinogenesis. This study aims to identify miRNAs in hepatocellular carcinoma (HCC) cells which might involve in oxidative stress response. An integrated analysis of miRNA expression signature was performed by employing robust rank aggregation (RRA) method, and four miRNAs (miR-34a-5p, miR-1915-3p, miR-638, and miR-150-3p) were identified as the oxidative stress-responsive miRNAs. Pathway enrichment analysis suggested that these four miRNAs played an important role in antiapoptosis process. Our data also revealed miR-34a-5p and miR-1915-3p, but not miR-150-3p and miR-638, were regulated by p53 in HCC cell lines under oxidative stress. In addition, clinical investigation revealed that these four miRNAs might be involved in oxidative stress response by targeting oxidative stress-related genes in HCC tissues. Kaplan-Meier analysis showed that these four miRNAs were associated with patients' overall survival. In conclusion, we identified four oxidative stress-responsive miRNAs, which were regulated by p53-dependent (miR-34a-5p and miR-1915-3p) and p53-independent pathway (miR-150-3p and miR-638). These four miRNAs may offer new strategy for HCC diagnosis and prognosis.

MicroRNA-34a inhibits tumor invasion and metastasis in osteosarcoma partly by effecting C-IAP2 and Bcl-2

Osteosarcoma is a common primary malignant bone tumor that occurs mainly in children and adolescents. Recent evidence has demonstrated that miR-34a is involved in the invasion and metastasis of osteosarcoma. This study aims to explore the effect of biological behavior of miR-34a on osteosarcoma. First, we collect osteosarcoma and adjacent specimens, and the relative expression of miR-34a and C-IAP2 messenger RNA was quantitated by real-time polymerase chain reaction. Furthermore, miR-34a stimulant is synthesized and transfected onto osteosarcoma MG-63 cells. The effect of overexpression of miR-34a on osteosarcoma was detected by colony-forming assay, Annexin V-fluorescein isothiocyanate Apoptosis Detection Kit I, Transwell assay, and animal experiment in vivo. Finally, the relative levels of C-IAP2 and Bcl-2 protein were checked by western blot, and the activity of caspase-3 and caspase-9 was tested by spectrophotometry assay. In conclusion, miR-34a was downregulated in osteosarcoma cells. And the expression of C-IAP2 and Bcl-2 protein was drastically inhibited, and the activities of caspase-3 and caspase-9 were significantly increased after transfecting miR-34a onto osteosarcoma MG-63 cells. And the overexpression of miR-34a can inhibit cell invasion and metastasis, promote cell apoptosis, and arrest cells in G0/G1 period. And the animal experiment in vivo demonstrated that the overexpression of miR-34a could significantly inhibit the growth of osteosarcoma in animal skin. Taken together, we indicated that miR-34a can inhibit tumor invasion and metastasis in osteosarcoma, and its mechanism may be partly related to downregulating the expression of C-IAP2 and Bcl-2 protein directly or indirectly.

The Microtubule Network and Cell Death Are Regulated by an miR-34a/Stathmin 1/βIII-Tubulin Axis

MicroRNA-34a (miR-34a) is a master regulator of signaling networks that maintains normal physiology and disease and is currently in development as a miRNA-based therapy for cancer. Prior studies have reported low miR-34a expression in osteosarcoma; however, the molecular mechanisms underlying miR-34a activity in osteosarcoma are not well-defined. Therefore, this study evaluated the role of miR-34a in regulating signal transduction pathways that influence cell death in osteosarcoma. Levels of miR-34a were attenuated in human osteosarcoma cells and xenografts of the Pediatric Preclinical Testing Consortium (PPTC). Bioinformatics predictions identified stathmin 1 (STMN1) as a potential miR-34a target. Biotin pull-down assay and luciferase reporter analysis confirmed miR-34a target interactions within the STMN1 mRNA 3'-untranslated region. Overexpression of miR-34a in osteosarcoma cells suppressed STMN1 expression and reduced cell growth in vitro Restoration of miR-34a led to microtubule destabilization and increased βIII-tubulin expression, with corresponding G1-G2 phase cell-cycle arrest and apoptosis. Knockdown of the Sp1 transcription factor, by siRNA silencing, also upregulated βIII-tubulin expression in osteosarcoma cells, suggesting that miR-34a indirectly affects Sp1. Validating the coordinating role of miR-34a in microtubule destabilization, when miR-34a was combined with either microtubule inhibitors or chemotherapy, STMN1 phosphorylation was suppressed and there was greater cytotoxicity in osteosarcoma cells. These results demonstrate that miR-34a directly represses STMN1 gene and protein expression and upregulates βIII-tubulin, leading to disruption of the microtubule network and cell death.Implications: The miR-34a/STMN1/βIII-tubulin axis maintains the microtubule cytoskeleton in osteosarcoma, and combining miR-34a with microtubule inhibitors can be investigated as a novel therapeutic strategy. Mol Cancer Res; 15(7); 953-64. ©2017 AACR.

Low Expression of Circulating MicroRNA-34c is Associated with Poor Prognosis in Triple-Negative Breast Cancer

PURPOSE

The microRNA-34 (miR-34) family is important in tumor regulation. This study aimed to investigate the association of circulating miR-34 family proteins with clinicopathological features and their prognostic value in triple-negative breast cancer (TNBC) patients.

MATERIALS AND METHODS

In this cohort study, 173 TNBC patients admitted to First People's Hospital of Shunde from May 1, 2009 to April 30, 2013 were enrolled. Meanwhile, 75 age-matched healthy women volunteers were identified as healthy controls (HCs). We examined the expression of miR-34 family (miR-34a/b/c) proteins in plasma collected from TNBC patients before any treatment was performed and from age-matched HCs using qPCR methods.

RESULTS

The expressions of miR-34a/34b/34c were significantly lower in TNBC patients than in HC (p<0.001, p=0.027, p<0.001, respectively). miR-34a was correlated with tumor grade (p=0.038), lymph node positive (p=0.027), distant metastasis (p=0.004), and surgery (p=0.023); miR-34b was correlated with lymph node positivity (p=0.027); and miR-34c was correlated with tumor grade (p=0.017) and distant metastasis (p<0.001). Kaplan-Meier curve analysis displayed low expression of miR-34a as associated with worse overall survival (OS) (p=0.011), as well as miR-34c low expression (p=0.002). In addition, univariate and multivariate Cox proportional hazards regression was performed, and low expression of miR-34c (p=0.011) was found to be an independent risk factor for OS, as well as tumor grade (p=0.013), lymph node positive (p=0.050), and distant metastasis (p=0.021).

CONCLUSION

In conclusion, this study demonstrated reduced miR-34a/c expression is highly associated with tumor progression and indicated worse prognosis. Also, miR-34c was an independent risk factor for OS in TNBC patients.

MicroRNA-34a suppresses colorectal cancer metastasis by regulating Notch signaling

Dysregulation of microRNA (miRNA/miR) expression is causally associated with cancer initiation and progression. However, the precise mechanisms by which dysregulated miRNAs induce colorectal tumorigenesis remain unknown. In the present study, downregulation of miR-34a was identified in colorectal cancer cell lines and clinical specimens. Clinical studies revealed that miR-34a expression was negatively associated with distant metastasis, and positively associated with differentiation and survival of human colorectal cancer specimens. In vitro miRNA functional assays demonstrated that miR-34a bound to the putative 3'-untranslated regions of Notch1 and Jagged1 in SW480 cells, and thereby attenuated the migration and invasion of the colon cancer cells. It was additionally identified that miR-34a downregulated the expression of vimentin and fibronectin via Notch1 and Jagged1. Overall, these data indicate that miR-34a serves a key role in suppressing colorectal cancer metastasis by targeting and regulating Notch signaling.