MicroRNA-326 functions as a tumor suppressor in glioma by targeting the Nin one binding protein (NOB1)

miR-326 overexpression inhibits colorectal cancer cell growth and proteasome activity by targeting PNO1: unveiling a novel therapeutic intervention strategy

Proteasome inhibition emerges as a promising strategy for cancer prevention. PNO1, pivotal for colorectal cancer (CRC) progression, is involved in proteasome assembly in Saccharomyces cerevisiae. Hence, we aimed to explore the role of PNO1 in proteasome assembly and its up- and down-streams in CRC. Here, we demonstrated that PNO1 knockdown suppressed CRC cells growth, proteasome activities and assembly, as well as CDKN1B/p27Kip1 (p27) degradation. Moreover, p27 knockdown partially attenuated the inhibition of HCT116 cells growth by PNO1 knockdown. The up-stream studies of PNO1 identified miR-326 as a candidate miRNA directly targeting to CDS-region of PNO1 and its overexpression significantly down-regulated PNO1 protein expression, resulting in suppression of cell growth, decrease of proteasome activities and assembly, as well as increasing the stability of p27 in CRC cells. These findings indicated that miR-326 overexpression can suppress CRC cell growth, acting as an endogenous proteasome inhibitor by targeting PNO1.

PRIM2: A Marker of MYC-driven Hyper-proliferation, Disease Progression, Tumor Aggressiveness and Poor Survival in Glioma Patients

BACKGROUND/AIM

Gliomas are the most prevalent brain tumors with metabolic alterations playing a pivotal role in disease progression. However, the precise coordination of metabolic alterations with tumor-promoting cellular mechanisms, leading to tumor initiation, progression, and aggressiveness, resulting in poor outcomes, remains poorly understood in gliomas.

MATERIALS AND METHODS

We conducted a metabolism-targeted differential gene expression analysis using glioma patients' expression profiling data from The Cancer Genome Atlas (TCGA) database. In addition, pathway enrichment analysis, gene set enrichment analysis (GSEA), transcription factor prediction, network construction, and correlation analyses were performed. Survival analyses were performed in R. All results were validated using independent GEO expression datasets.

RESULTS

Metabolism-targeted analysis identified 5 hits involved in diverse metabolic processes linking them to disease aggressiveness in gliomas. Subsequently, we established that cell cycle progression and hyper-proliferation are key drivers of tumor progression and aggressiveness in gliomas. One of the identified metabolic hits, DNA primase 2 (PRIM2), a gene involved in DNA replication was found directly associated with cell cycle progression in gliomas. Furthermore, our analysis indicated that PRIM2, along with other cell cycle-related genes, is under the control of and regulated by the oncogenic MYC transcription factor in gliomas. In addition, PRIM2 expression alone is enough to predict MYC-driven cell cycle progression and is associated with tumor progression, aggressive disease state, and poor survival in glioma patients.

CONCLUSION

Our findings highlight PRIM2 as a marker of MYC-driven cell cycle progression and hyper-proliferation, disease onset and progression, tumor aggressiveness, and poor survival in glioma patients.

circRNA-SMO upregulates CEP85 to promote proliferation and migration of glioblastoma via sponging miR-326

Circular RNAs (circRNAs) play an important role in cancer development by sponging microRNAs (miRNAs) to regulate the signaling axis. However, more comprehensive mechanisms of circRNAs in glioblastoma need to be elucidated. RT-qPCR was used to detect the expression levels of circRNA-SMO and miR-326. Dual-luciferase reporter assays were conducted to verify the interaction among circRNA-SMO, miR-326, and CEP85. Flow cytometric analysis was performed to detect apoptosis. Western blotting was used to determine the protein levels of the different molecules. Animal xenograft experiments were performed to evaluate the role of circRNA-SMO in vivo. CircRNA-SMO was upregulated in glioblastoma tissues and glioblastoma cells. CircRNA-SMO downregulation inhibited the viability and colony-forming ability of the glioblastoma cells. In addition, miR-326 was downregulated in glioblastoma cells, which was verified to sponge circRNA-SMO and interact with CEP85. Moreover, circRNA-SMO inhibition induced the elevation of miR-326 and apoptosis, accompanied by a decrease in CEP85. CircRNA-SMO knockdown-mediated tumor inhibition was prevented by an miR-326 inhibitor. Furthermore, circRNA-SMO inhibition inhibited tumor growth in vivo, accompanied by an increase in miR-326 and a decline in CEP85 in tumor tissues. Conclusions. CircRNA-SMO sponges miR-326 to promote glioblastoma proliferation and migration by upregulating CEP85 expression. This study clarified the role of circRNA-SMO in the development of glioblastoma, providing novel insights for its treatment.

MicroRNA-326 negatively regulates CD155 expression in lung adenocarcinoma

Treatment with immune checkpoint inhibitors induces a durable response in some patients with non-small-cell lung cancer, but eventually gives rise to drug resistance. Upregulation of CD155 expression is implicated as one mechanism of resistance to programmed death receptor-1 (PD-1)/PD-1 ligand (PD-L1) inhibitors, and it is therefore important to characterize the mechanisms underlying regulation of CD155 expression in tumor cells. The aim of this study was to identify microRNAs (miRNAs) that might regulate CD155 expression at the posttranscriptional level in lung cancer. Comprehensive miRNA screening with target prediction programs and a dual-luciferase reporter assay identified miR-346, miR-328-3p, miR-326, and miR-330-5p as miRNAs that bind to the 3'-UTR of CD155 mRNA. Forced expression of these miRNAs suppressed CD155 expression in lung cancer cell lines. Immunohistochemical staining of CD155 in tissue specimens from 57 patients with lung adenocarcinoma revealed the median tumor proportion score for CD155 to be 68%. The abundance of miR-326 in these specimens with a low level of CD155 expression was significantly greater than in specimens with a high level (p < 0.005). Our results thus suggest that miR-326 negatively regulates CD155 expression in lung adenocarcinoma and might therefore play a role in the development of resistance to PD-1/PD-L1 inhibitors.

miRNA-612 suppresses ovarian cancer cell tumorigenicity by downregulating NOB1

MicroRNAs (miRNAs) play crucial roles in cancer progression. Our previous study demonstrated that NIN1/RPN12 binding protein 1 homolog (NOB1) was a functional regulator in the progression of ovarian cancer (OC). However, the role of miRNA-612 (miR-612) in OC has not been elucidated. In this study, we aimed to investigate the regulatory mechanism of NOB1 targeting miRNA, miR-612, in OC tumorigenicity. The miR-612 expression was down-regulated in OC patient tissues and four OC cell lines (Caov3, A2780, SKOV3 and OVCAR3). The miR-612 level was negatively correlated with NOB1 expression, and dual-luciferase reporter assay indicated that miR-612 suppressed NOB1 expression by targeting the 3'UTR of NOB1 transcript. Up-regulation of miR-612 mediated by lentiviral transduction suppressed cell proliferation, colony formation, migration, invasion, and induced apoptosis in OC cell lines. In addition, miR-612 overexpression inhibited tumor growth of OC in vivo by sequestering NOB1 expression. In conclusion, our results suggested that miR-612 directly targeted NOB1 to suppress OC progression. Therefore, the miR-612-NOB1 axis could serve as therapeutic targets for OC.

The effects of hsa_circ_0000517/miR-326 axis on the progression of breast cancer cells and the prediction of miR-326 downstream targets in breast cancer

It has been proposed that circular RNAs (circRNAs) play crucial roles in the initiation and progression of various cancers including breast cancer. Our study aimed to determine the function and regulatory mechanism of hsa_circ_0000517 in breast cancer. qRT-PCR was applied to determine hsa_circ_0000517 expression in breast cancer cells. The circular structure of hsa_circ_0000517 was confirmed using RNase R digestion assay. The subcellular distribution of hsa_circ_0000517 was analyzed using nuclear mass separation assay. Effects of hsa_circ_0000517 on the malignant behaviors of breast cancer cells were determined using CCK-8, colony formation assay, flow cytometry analysis, caspase-3 activity assay, and Transwell invasion assay. Bioinformatics analysis, luciferase reporter assay, and RIP were used to predict and confirm the interaction between hsa_circ_0000517 and miR-326. Bioinformatics analysis was used to search the possible targets of miR-326. Hsa_circ_0000517 was upregulated in breast cancer tissues and cells. Hsa_circ_0000517 was a stable circularized transcript that was preferentially distributed in the cytoplasm. Hsa_circ_0000517 knockdown inhibited cell proliferation, colony formation ability, and invasion and triggered apoptosis in breast cancer cells. Hsa_circ_0000517 acted as a sponge of miR-326 to suppress its expression. miR-326 inhibition abolished the effects of hsa_circ_0000517 knockdown on the malignant behaviors of breast cancer cells. Totally 17 genes were identified as the potential targets of miR-326 in breast cancer. In conclusion, hsa_circ_0000517 silencing repressed breast cancer progression by upregulating miR-326 expression.

Circulating microRNAs in Early Breast Cancer Patients and Its Association With Lymph Node Metastases

MicroRNAs have emerged as important regulators of the metastatic process. In addition, circulating miRNAs appear to be surprisingly stable in peripheral blood making them ideal noninvasive biomarkers for disease diagnosis. Here, we performed a proof-of-principle study to investigate the expression profile of circulating miRNAs and their association with the metastatic lymph node status in early breast cancer patients. Sentinel lymph node status was detected by one-step nucleic acid (OSNA) analysis. We performed RNA-sequencing in 16 plasma samples and validated the results by qPCR. Gene Ontology term enrichment and KEGG pathway analyses were carried out using DAVID tools. We found16 differentially expressed miRNAs (q < 0.01) in patients with positive SLNs. Fourteen miRNAs were down-regulated (miR-339-5p, miR-133a-3p, miR-326, miR-331-3p, miR-369-3p, miR-328-3p, miR-26a-3p, miR-139-3p, miR-493-3p, miR-664a-5p, miR-146a-5p, miR-323b-3p, miR-1307-3p and miR-423-3p) and 2 were up-regulated (miR-101-3pand miR-144-3p). Hierarchical clustering using differentially expressed miRNAs clearly distinguished patients according to their lymph node status. Gene ontology analysis showed a significant enrichment of biological processes associated with the regulation of the epithelial mesenchymal transition, cell proliferation and transcriptional regulation. Our results suggest the potential role of several circulating miRNAs as surrogate markers of lymph node metastases in early breast cancer patients. Further validation in a larger cohort of patients will be necessary to confirm our results.

Characterization of microRNA expression in B cells derived from Japanese black cattle naturally infected with bovine leukemia virus by deep sequencing

Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL), a malignant B cell lymphoma. However, the mechanisms of BLV-associated lymphomagenesis remain poorly understood. Here, after deep sequencing, we performed comparative analyses of B cell microRNAs (miRNAs) in cattle infected with BLV and those without BLV. In BLV-infected cattle, BLV-derived miRNAs (blv-miRNAs) accounted for 38% of all miRNAs in B cells. Four of these blv-miRNAs (blv-miR-B1-5p, blv-miR-B2-5p, blv-miR-B4-3p, and blv-miR-B5-5p) had highly significant positive correlations with BLV proviral load (PVL). The read counts of 90 host-derived miRNAs (bta-miRNAs) were significantly down-regulated in BLV-infected cattle compared to those in uninfected cattle. Only bta-miR-375 had a positive correlation with PVL in BLV-infected cattle and was highly expressed in the B cell lymphoma tissue of EBL cattle. There were a few bta-miRNAs that correlated with BLV tax/rex gene expression; however, BLV AS1 expression had a significant negative correlation with many of the down-regulated bta-miRNAs that are important for tumor development and/or tumor suppression. These results suggest that BLV promotes lymphomagenesis via AS1 and blv-miRNAs, rather than tax/rex, by down-regulating the expression of bta-miRNAs that have a tumor-suppressing function, and this downregulation is linked to increased PVL.

Establishment of an Immune-Related Gene Signature for Risk Stratification for Patients with Glioma

Glioma is a frequently seen primary malignant intracranial tumor, characterized by poor prognosis. The study is aimed at constructing a prognostic model for risk stratification in patients suffering from glioma. Weighted gene coexpression network analysis (WGCNA), integrated transcriptome analysis, and combining immune-related genes (IRGs) were used to identify core differentially expressed IRGs (DE IRGs). Subsequently, univariate and multivariate Cox regression analyses were utilized to establish an immune-related risk score (IRRS) model for risk stratification for glioma patients. Furthermore, a nomogram was developed for predicting glioma patients' overall survival (OS). The turquoise module (cor = 0.67; P < 0.001) and its genes (n = 1092) were significantly pertinent to glioma progression. Ultimately, multivariate Cox regression analysis constructed an IRRS model based on VEGFA, SOCS3, SPP1, and TGFB2 core DE IRGs, with a C-index of 0.811 (95% CI: 0.786-0.836). Then, Kaplan-Meier (KM) survival curves revealed that patients presenting high risk had a dismal outcome (P < 0.0001). Also, this IRRS model was found to be an independent prognostic indicator of gliomas' survival prediction, with HR of 1.89 (95% CI: 1.252-2.85) and 2.17 (95% CI: 1.493-3.14) in the Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) datasets, respectively. We established the IRRS prognostic model, capable of effectively stratifying glioma population, convenient for decision-making in clinical practice.

Circular RNA circHIPK3 promotes breast cancer progression via sponging MiR-326

Background: This study investigated the potential molecular mechanism of circular RNA HIPK3 (circHIPK3) in breast cancer (BCa). Methods: BCa cells were transfected with miR-326 mimic, miR-326 inhibitor, circHIPK3, sicircHIPK3. The expressions of circHIPK3 and miR-326 in BCa tissues and BCa cell lines were determined by RT-qPCR. Cell viability, colony formation, migration, invasion, and apoptosis of the cells were detected by CCK-8 and colony formation, wound-healing, transwell and flow cytometric assays, respectively. The relationship between circHIPK3 and miR-326 was analyzed and confirmed by circInteractome, dual-luciferase reporter, RT-qPCR, Pearson's correlation assays. Western blot and RT-qPCR were performed to determine the expressions of apoptosis-related molecules (Bcl-2, Bax, and cleaved Caspase-3) and EMT-related molecules (E-cadherin, N-cadherin, and Vimentin) in the BCa cells and tumor tissues. The tumor growth in mice was examined in a xenograft tumor model in which Ki-67 expression was determined by immunohistochemistry (IHC). Results: In BCa, the expression of circHIPK3 was up-regulated and that of miR-326 was down-regulated. CircHIPK3 knockdown inhibited the cell proliferation, invasion, and migration. MiR-326 was the direct target of circHIPK3, and was inversely correlated with circHIPK3 expression. CircHIPK3 overexpression promoted proliferation, migration, invasion, apoptosis resistance, and tumor growth and up-regulated Ki-67 expression, at the same time, the expressions of Bcl-2, N-cadherin, Vimentin were up-regulated, and those of Bax, cleaved Caspase-3 and E-cadherin were inhibited. These above expressions were partially reversed by miR-326 overexpression. Conclusion: CircHIPK3 sponges miR-326 to promote BCa growth and metastasis. The current findings provide a novel therapeutic target for treating BCa.

Long noncoding RNA SNHG9 facilitates growth of glioma stem-like cells via miR-326/SOX9 axis

BACKGROUND

Glioma stem-like cells (GSCs) are greatly responsible for the progression of glioma. Long noncoding RNAs (lncRNAs) play an important role in glioma tumor progression. This study aims to explore the role and underlying mechanism of lncRNA SNHG9 in regulating GSC cell growth.

METHODS

GSCs were obtained from glioma cells (U87 and U251) and referred to as GSC-87 and GSC-251, respectively. The interactions between miR-326 and SNHG9 or SOX9 were analyzed using luciferase reporter assay. Cell growth of GSCs was evaluated by EdU assay and sphere formation assay.

RESULTS

SNHG9 expression was significantly higher in GSC-87 and GSC-251 cells than in U87 and U251 cells. SNHG9 overexpression promoted GSC cell growth, whereas SNHG9 knockdown inhibited GSC cell growth. Mechanistically, SNHG9 acted as a competitive endogenous RNA of miR-326 to elevate the expression of SOX9, a direct target of miR-326. Moreover, transfection with miR-326 inhibitor counteracted SNHG9 knockdown-mediated inhibition of GSC cell growth.

CONCLUSIONS

SNHG9 facilitates growth of GSCs via the miR-326/SOX9 axis. This study provides a promising therapeutic target for glioma treatment.

Circular RNA hsa_circ_0005397 promotes hepatocellular carcinoma progression by regulating the miR-326/PDK2 axis

INTRODUCTION

Circular RNAs (circRNAs) are associated with the initiation and progression of cancer. However, the biological functions and underlying mechanism of hsa_circ_0005397 in hepatocellular carcinoma (HCC) have not been fully elucidated.

METHODS

Hemotoxylin and eosin staining was used to assess histological changes. The expression levels of hsa_circ_0005397, miR-326 and pyruvate dehydrogenase kinase 2 (PDK2) were measured by a quantitative real-time polymerase chain reaction. Cell proliferation was evaluated by cell counting kit-8 and colony formation assays. Cell cycle distribution and apoptosis were detected by flow cytometry analysis. Caspase-3 activity was determined by a caspase-3 activity kit. Wound healing and transwell assays were used to evaluate cell migration and invasion. A western blot assay was performed to measure the expression of cyclin D1, p21, matrix metalloproteinase (MMP)2, MMP9, PDK2 and PCNA. The interaction between miR-326 and hsa_circ_0005397 or PDK2 was confirmed by dual-luciferase reporter, RNA immunoprecipitation and RNA pull-down assays. Xenograft tumor models were established to confirm the role of hsa_circ_0005397 in vivo.

RESULTS

Hsa_circ_0005397 and PDK2 were up-regulated, whereas miR-326 was down-regulated in HCC tissues and cells. Hsa_circ_0005397 knockdown inhibited cell proliferation and metastasis, and promoted apoptosis. miR-326 was a direct target of hsa_circ_0005397, and inhibition of miR-326 reversed the inhibitory effect of hsa_circ_0005397 silencing on HCC progression. Moreover, PDK2 was a direct target of miR-326 and PDK2 overexpression abated the anti-cancer roles of miR-326 in HCC. Additionally, hsa_circ_0005397 regulated PDK2 expression by sponging miR-326. Furthermore, hsa_circ_0005397 down-regulation suppressed tumor growth by up-regulating miR-326 and down-regulating PDK2.

CONCLUSIONS

Hsa_circ_0005397 facilitates HCC progression by regulating the miR-326/PDK2 axis, providing a promising circRNA-targeted therapy for HCC.

Knockdown of circ0082374 inhibits cell viability, migration, invasion and glycolysis in glioma cells by miR-326/SIRT1

Circular RNAs (circRNAs) play important roles in the development and treatment of glioma. However, the role and mechanism of circRNA carboxypeptidase A4 (circ0082374) in glioma are largely unknown. Forty-two glioma patients and 28 normal patients were recruited. Glioma cell lines A172 and U251 were used for functional assays. The expression levels of circ0082374, microRNA-326 (miR-326) and sirtuin 1 (SIRT1) were examined via quantitative real-time polymerase chain reaction or western blot. Cell viability, migration, invasion and glycolysis were measured via cell counting kit-8, trans-well, oxygen consumption rate and western blot, respectively. The target correlation of circ0082374/miR-326 or miR-326/SIRT1 was explored via dual-luciferase reporter, RNA immunoprecipitation and pull-down assays. The role of circ0082374 in vivo was investigated via xenograft model. We found circ0082374 expression was elevated in glioma tissues and cells. Knockdown of circ0082374 suppressed the viability, migration, invasion and glycolysis in glioma cells. miR-326 was a target of circ0082374 and miR-326 knockdown attenuated the inhibitive role of circ0082374 silence in glioma progression. SIRT1 was a target of miR-326 and circ0082374 could promote SIRT1 expression by sponging miR-326. Silence of SIRT1 reversed the promoting effect of circ0082374 on glioma progression. Knockdown of circ0082374 reduced xenograft tumor growth by miR-326/SIRT1 in vivo. Collectively, silence of circ0082374 repressed the viability, migration, invasion and glycolysis in glioma cells by regulating miR-326 and SIRT1 in a ceRNA mechanism, providing a new mechanism for the pathogenesis of glioma.

The circRNA circ_0000291 acts as a sponge of microRNA 326 to regulate E26 transformation-specific sequence-1 expression and promote breast cancer progression

Accumulating studies authenticate that circular RNAs (circRNAs) are involved in the progression of cancers. However, their role in breast cancer (BC) remains largely unknown. In this study, real-time polymerase chain reaction was employed to detect the circ_0000291 and miR-326 expressions in BC tissues and cells. The correlation between the expression level of circ_0000291 and clinicopathological parameters of BC patients was analyzed. Western blot was used to detect the expression of E26 transformation-specific sequence-1 (ETS1), E-cadherin, N-cadherin and Vimentin in BC cells. Cell proliferation was measured using the cell counting kit-8 assay and the bromodeoxyuridine assay. Cell migration and invasion were detected by Transwell assay. The interactions between circ_0000291 and miR-326, miR-326 and ETS1 were verified using bioinformatics prediction, the dual-luciferase reporter gene assay or/and RNA binding protein immunoprecipitation assay. We demonstrated that circ_0000291 was significantly upregulated in BC, and its high expression was positively correlated with T stage and local lymph node metastasis. Functional assays validated that circ_0000291 promoted BC cell proliferation, migration and invasion. The mechanism studies indicated that circ_0000291 could decoy miR-326 and in turn upregulate the expression of ETS1. In conclusion, circ_0000291 is the novel oncogenic circRNA and promotes BC progression via modulating the miR-326/ETS1 axis.

Expression of miR-495 and miR-326 in peripheral blood of rheumatoid arthritis patients and its significance

The aim of the present study was to investigate the expression of microRNA (miR)-495 and miR-326 in the peripheral blood of patients with rheumatoid arthritis (RA). A total of 107 RA patients, admitted to the Yidu Central Hospital of Weifang (Weifang, China) from February 2016 to February 2019, and 112 healthy subjects, who underwent physical examination during the same period, were selected as the research subjects for prospective analysis. The RA patients served as the study group and the healthy subjects as the control group. The expression levels of miR-495 and miR-326 in the peripheral blood of the two groups of subjects were compared. The association between miR-495 and miR-326 with RA clinical pathology and the diagnostic value of miR-495 and miR-326 for RA were analyzed. In the study group, miR-495 expression was significantly higher than that in the control group, and miR-326 expression was significantly lower than that in the control group (P<0.001). miR-495 and miR-326 combined diagnosis showed good predictive value for the occurrence of RA (P<0.001) and was closely related to RA clinical pathology (P<0.001). After treatment, miR-495 expression was significantly decreased in the study group, whereas miR-326 expression was significantly increased (P<0.001). Pearson's correlation coefficient analysis showed that rheumatoid factor (RF) was positively correlated with miR-495 expression and negatively correlated with miR-326 expression (P<0.001). In conclusion, miR-495 was highly expressed in patients with RA, whereas miR-326 was poorly expressed in RA patients, and the combined detection of miR-495 and miR-326 has good diagnostic value for RA.

Screening and bioinformatics analysis of a ceRNA network based on the circular RNAs, miRNAs, and mRNAs in pan-cancer

Background

The pan‐cancer analysis has recently brought us into a novel level of cancer research. Nowadays, the Circular RNAs (circRNAs) is becoming increasingly important in the occurrence and progression of tumors. Nevertheless, the specific expression patterns and functions of circRNAs in the pan‐cancer remains unclear. Here we aimed to explore the expression patterns and functions of circRNAs in pan‐cancer.

Methods

We combined our microarray with seven circRNA arrays from the Gene Expression Omnibus (GEO) database and transcriptome profiles were acquired from The Cancer Genome Atlas (TCGA) database. A circRNA‐miRNA‐mRNA network was created and analyzed using multiple bioinformatic approaches including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, Search Tool for the Retrieval of Interacting Genes (STRING) database, cytoHubba and MCODE app. Cell function assays including CCK‐8 analysis, colony formation, and transwell assay were used to explore pan‐circRNAs’ functions.

Results

A panel of 6 circRNAs, 11 miRNAs, and 318 mRNAs was found to be differentially expressed (DE) in pan‐cancer. A circRNA‐miRNA‐mRNA network was also constructed. Then, a circRNA‐miRNA‐hub gene network was created according to 5 pan‐circRNAs, 8 pan‐miRNAs, and 16 pan‐mRNAs. Enrichment analysis pointed out the possible association of DEmRNAs with pan‐cancer is transcriptional misregulation in cancer. Overexpression of hsa_circ_0004639 and silence of hsa_circ_0008310 can inhibit the malignant biological properties of cancer cells.

Conclusions

Six pan‐circRNAs were discovered and their regulating mechanisms were predicted. Those findings together will give a new insight into pan‐cancer research and present potential therapy targeting as well as promising biomarkers.

Long non-coding RNA NBAT1 inhibits the progression of glioma through the miR-21/SOX7 axis

Glioma is one of the most prevalent types of malignancy in the central nervous system worldwide, and the prognosis of patients with late stage glioma remains poor. Thus, the development of promising therapeutic strategies against glioma is essential. Long non-coding RNAs (lncRNAs) are functional RNA molecules involved in the initiation and progression of tumors, including glioma. Investigation on the regulatory roles of lncRNAs may facilitate the development of effective treatments. lncRNA NBAT1 is associated with the growth and metastasis of cancer; however, its underlying molecular mechanisms remain unknown. Thus, the present study aimed to investigate the effects of NBAT1 in glioma. The expression levels of NBAT1, microRNA (miRNA/miR)-21 and SOX7 in patients with glioma, and healthy donors using reverse transcription-quantitative PCR analysis. Human glioma cells (A172 and AM138) and normal astrocytes were used to establish the NBAT1-knockdown and overexpression models. Cell Counting Kit-8 and Transwell assays were performed to determine whether NBAT1 exerted effects on cell proliferation, migration and invasion. The results demonstrated that NBAT1 expression decreased in glioma tissues compared to normal samples. Additionally, downregulation of NBAT1 was detected in human glioma cells compared with normal astrocytes. Overexpression of NBAT1 inhibited glioma cell proliferation, migration and invasion. In addition, miR-21 was identified as a potential target of NBAT1, and the effects of miR-21-induced cell proliferation and metastasis were reversed following overexpression of NBAT1. Furthermore, SOX7 was predicted as the potential target of miR-21, and its expression was upregulated in glioma cells by overexpression of NBAT1 compared with the vehicle only control. Taken together, the results of the present study provide novel insight into the functions of NBAT1 in glioma, suggesting that the NBAT1/miR-21/SOX7 axis may act as a potential therapeutic target for the treatment of patients with glioma.

Multivariate analysis reveals differentially expressed genes among distinct subtypes of diffuse astrocytic gliomas: diagnostic implications

Diagnosis and classification of gliomas mostly relies on histopathology and a few genetic markers. Here we interrogated microarray gene expression profiles (GEP) of 268 diffuse astrocytic gliomas-33 diffuse astrocytomas (DA), 52 anaplastic astrocytomas (AA) and 183 primary glioblastoma (GBM)-based on multivariate analysis, to identify discriminatory GEP that might support precise histopathological tumor stratification, particularly among inconclusive cases with II-III grade diagnosed, which have different prognosis and treatment strategies. Microarrays based GEP was analyzed on 155 diffuse astrocytic gliomas (discovery cohort) and validated in another 113 tumors (validation set) via sequential univariate analysis (pairwise comparison) for discriminatory gene selection, followed by nonnegative matrix factorization and canonical biplot for identification of discriminatory GEP among the distinct histological tumor subtypes. GEP data analysis identified a set of 27 genes capable of differentiating among distinct subtypes of gliomas that might support current histological classification. DA + AA showed similar molecular profiles with only a few discriminatory genes overexpressed (FSTL5 and SFRP2) and underexpressed (XIST, TOP2A and SHOX2) in DA vs AA and GBM. Compared to DA + AA, GBM displayed underexpression of ETNPPL, SH3GL2, GABRG2, SPX, DPP10, GABRB2 and CNTN3 and overexpression of CHI3L1, IGFBP3, COL1A1 and VEGFA, among other differentially expressed genes.

The value of circulating microRNAs for early diagnosis of B-cell lymphoma: A case-control study on historical samples

MicroRNAs are small regulatory RNAs that are deregulated in a wide variety of human cancers, including different types of B-cell lymphoma. Nevertheless, the feasibility of circulating microRNA for early diagnosis of B-cell lymphoma has not been established. To address the possibility of detecting specific circulating microRNAs years before a B-cell lymphoma is diagnosed, we studied the plasma expression of microRNA first in pre-treatment samples from patients with diffuse large B-cell lymphoma and subsequently in repository samples from blood donors who later developed B-cell lymphomas. In addition, we studied the microRNA expression in the diagnostic lymphoma biopsy. The most strongly induced (miR-326) and suppressed (miR-375) plasma microRNA at diagnosis, when compared with healthy blood donors, were also substantially up- or down-regulated in plasma repository samples taken from several months to up to two years before the blood donors were diagnosed with B-cell lymphoma. Importantly, at these time points the donors had no signs of disease and felt healthy enough to donate blood. In conclusion, this first study of plasma microRNA profiles from apparently healthy individuals, taken several years before B-cell lymphoma diagnosis, suggests that plasma microRNA profiles may be predictive of lymphoma development.

Recent Trends of microRNA Significance in Pediatric Population Glioblastoma and Current Knowledge of Micro RNA Function in Glioblastoma Multiforme

Central nervous system tumors are a significant problem for modern medicine because of their location. The explanation of the importance of microRNA (miRNA) in the development of cancerous changes plays an important role in this respect. The first papers describing the presence of miRNA were published in the 1990s. The role of miRNA has been pointed out in many medical conditions such as kidney disease, diabetes, neurodegenerative disorder, arthritis and cancer. There are several miRNAs responsible for invasiveness, apoptosis, resistance to treatment, angiogenesis, proliferation and immunology, and many others. The research conducted in recent years analyzing this group of tumors has shown the important role of miRNA in the course of gliomagenesis. These particles seem to participate in many stages of the development of cancer processes, such as proliferation, angiogenesis, regulation of apoptosis or cell resistance to cytostatics.

Silencing NOB1 Can Affect Cell Proliferation and Apoptosis Via the C-Jun N-Terminal Kinase Pathway in Colorectal Cancer

OBJECTIVES

To investigate the bio-functions and the molecular mechanisms of NIN1/proteasome 26S subunit non-ATPase 8 binding protein 1 homolog (NOB1) in colorectal cancer cells.

METHODS

NOB1 expression was silenced using si-RNA in SW480 and LoVo cells. The transfection efficiency was measured by western blotting and RT-qPCR. Subsequently, the proliferation of SW480 and LoVo cells was determined using both MTT assay and colony-formation assay. Apoptosis and cell cycle analysis were determined using flow cytometry.

RESULTS

Compared with the normal control (NC) and scramble cells, si-NOB1 could significantly attenuate the proliferation, colony-formation ability and cell percentage of S stage (p < 0.05). Additionally, at the phosphorylation level, si-NOB1 could notably increase the expression of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) and p38.

CONCLUSIONS

Inhibition of NOB1 expression suppressed the proliferation, and promoted the apoptosis through regulation of the JNK signaling pathway.

MiR-326: Promising Biomarker for Cancer

MicroRNAs (miRNAs) are small non-coding and highly conserved RNAs that act in biological processes including cell proliferation, invasion, apoptosis, metabolism, signal transduction, and tumorigenesis. The previously identified miRNA-326 (miR-326) has been reported to participate in cellular apoptosis, tumor growth, cell invasion, embryonic development, immunomodulation, chemotherapy resistance, and oncogenesis. This review presents a detailed overview of what is known about the effects of miR-326 on cell invasion, metastasis, drug resistance, proliferation, apoptosis, and its involvement in signaling pathways.

MicroRNA-326 decreases tau phosphorylation and neuron apoptosis through inhibition of the JNK signaling pathway by targeting VAV1 in Alzheimer's disease

Alzheimer's disease (AD) is a progressive and age-related neurological dysfunction. Abundant data have profiled microRNA (miR) patterns in healthy, aging brain, and in the moderate and late-stages of AD. Herein, this study aimed to explore whether miR-326 could influence neuron apoptosis in AD mice and how miR-326 functions in this process. The candidate differentially expressed gene VAV1 was obtained by microarray analysis, and miRNAs that could regulate VAV1 candidate gene were predicted. Luciferase activity determination confirmed VAV1 as a target gene of miR-326. AD mice models were established for investigating the effect of miR-326 on AD mice. The overexpression of miR-326 contributed to decreased time of the mice to find the platform and the escape latency and increased residence time on the target area. Besides, elevation of miR-326 decreased Aβ deposition and contents of Aβ_1-40 and Aβ_1-42 . Moreover, miR-326 overexpression increased neuron cell ability, mediated cell entry, and inhibited neuron apoptosis via JNK signaling pathway. Of crucial importance, miR-326 negatively regulated the expression of VAV1, inhibited tau phosphorylation, and blocked the activation of the JNK signaling pathway. Taken together these observations, we demonstrate that miR-326 improves cognitive function of AD mice and inhibits neuron apoptosis in AD mice through inactivation of the JNK signaling pathway by targeting VAV1. Based on those findings, miR-326 might exert promise as target for the treatment of AD.

Assessment of miR-98-5p, miR-152-3p, miR-326 and miR-4289 Expression as Biomarker for Prostate Cancer Diagnosis

Prostate cancer (PCa) is one of the most commonly diagnosed cancers worldwide, accounting for almost 1 in 5 new cancer diagnoses in the US alone. The current non-invasive biomarker prostate specific antigen (PSA) has lately been presented with many limitations, such as low specificity and often associated with over-diagnosis. The dysregulation of miRNAs in cancer has been widely reported and it has often been shown to be specific, sensitive and stable, suggesting miRNAs could be a potential specific biomarker for the disease. Previously, we identified four miRNAs that are significantly upregulated in plasma from PCa patients when compared to healthy controls: miR-98-5p, miR-152-3p, miR-326 and miR-4289. This panel showed high specificity and sensitivity in detecting PCa (area under the curve (AUC) = 0.88). To investigate the specificity of these miRNAs as biomarkers for PCa, we undertook an in depth analysis on these miRNAs in cancer from the existing literature and data. Additionally, we explored their prognostic value found in the literature when available. Most studies showed these miRNAs are downregulated in cancer and this is often associated with cancer progression and poorer overall survival rate. These results suggest our four miRNA signatures could potentially become a specific PCa diagnostic tool of which prognostic potential should also be explored.

Non-Coding RNAs in Glioma

Glioma is the most aggressive brain tumor of the central nervous system. The ability of glioma cells to migrate, rapidly diffuse and invade normal adjacent tissue, their sustained proliferation, and heterogeneity contribute to an overall survival of approximately 15 months for most patients with high grade glioma. Numerous studies indicate that non-coding RNA species have critical functions across biological processes that regulate glioma initiation and progression. Recently, new data emerged, which shows that the cross-regulation between long non-coding RNAs and small non-coding RNAs contribute to phenotypic diversity of glioblastoma subclasses. In this paper, we review data of long non-coding RNA expression, which was evaluated in human glioma tissue samples during a five-year period. Thus, this review summarizes the following: (I) the role of non-coding RNAs in glioblastoma pathogenesis, (II) the potential application of non-coding RNA species in glioma-grading, (III) crosstalk between lncRNAs and miRNAs (IV) future perspectives of non-coding RNAs as biomarkers for glioma.

microRNA-744 is downregulated in glioblastoma and inhibits the aggressive behaviors by directly targeting NOB1

In recent years, changes in microRNA (miRNA) expression have been detected in almost all human cancer types, including glioblastoma (GBM). Dysregulation of miRNAs may play tumor-suppressing or oncogenic roles in the initiation and progression of GBM, and may be involved in the regulation of multiple pathological behaviors. Therefore, identifying the clinical value and functional role of GBM-related miRNAs may provide effective therapeutic targets for the treatment of patients with this fatal malignancy. Dysregulation of miR-744 has been identified in several human cancer types. However, to the best of our knowledge, little is known concerning the expression pattern and biological roles of miR-744 in GBM. In this study, we found that miR-744 was significantly downregulated in GBM tissues and cell lines. Decreased miR-744 expression was significantly correlated with the Karnofsky Performance Scale (KPS) and World Health Organization (WHO) grade in GBM patients. miR-744 upregulation inhibited the proliferation, colony formation, migration, and invasion, in addition to inducing apoptosis of GBM cells in vitro. Inhibition of miR-744 had the opposite effect on these behaviors in GBM cells. Additionally, miR-744 attenuated the tumor growth of GBM cells in vivo. Furthermore, NIN1/RPN12 binding protein1 homolog (NOB1) was identified as a direct target gene of miR-744 in GBM cells. NOB1 was confirmed to be upregulated in GBM tissues, and this was inversely correlated with upregulation of miR-744 expression. Moreover, NOB1 knockdown exhibited similar inhibitory effects as miR-744 overexpression in GBM cells. Notably, recovered NOB1 expression counteracted the tumor-suppressing roles of miR-744 in the malignant phenotypes of GBM cells. Taken together, these results demonstrate that miR-744 directly targets NOB1 to inhibit the aggressive behaviors of GBM cells. Hence, the miR-744/NOB1 axis may be useful in the identification of novel therapies for GBM patients.

Long noncoding RNA H19, and not microRNA miR-326, is over-expressed and predicts survival in glioblastoma

Glioblastoma (GB) represents the most common malignant brain tumor, which, despite extensive research, remains of poor prognosis. The focus of recent studies of GB pathogenesis has shifted to the study of the role of noncoding RNAs (ncRNAs). In this study, we examined the expression levels of the microRNA miR-326 and the long ncRNA H19 (on which a miR-326 putative binding site was found by in-silico analysis) in brain tumor tissue from GB patients as compared to cancer-free brain tissue. Relative expression levels of miR-326 were not found to be significantly altered in GB patients. By comparison, H19 was consistently over-expressed in all GB patients (p < 0.001), and correlated with poorer overall survival (OS) and progression-free survival (PFS) (p = 0.026 and p = 0.045, respectively). At a cutoff value of 5.27, H19 up-regulation could predict OS in GB patients, with a 71.4% sensitivity and 59.6% specificity (p = 0.026). The current GB patients were clustered by the multivariate analysis into 4 groups based on miR-326 and H19 expression profiles, age at diagnosis, and PFS. Our data suggest a role for H19 in the pathogenesis of GB and could be a potential prognostic biomarker for GB.

Long non-coding RNA in glioma: signaling pathways

Glioma is regarded as the most prevalent malignant carcinoma of the central nervous system. Thus, the development of new therapeutic strategies targeting glioma is of significant clinical importance. Long non-coding RNAs (lncRNAs) are functional RNA molecules without a protein-coding function and are reportedly involved in the initiation and progression of glioma. Dysregulation of lncRNAs in glioma is due to activation of several signaling pathways, such as the BRD4-HOTAIR-β-catenin/PDCD4, p53-Hif-H19/IGF2 and CRNDE/mTOR pathways. Furthermore, microRNAs (miRNAs) such as miR-675 also interact with lncRNAs in glioma. Thus, exploring the mechanisms by which lncRNA control processes will be instrumental for devising new effective therapies against glioma.

Blood transcriptional and microRNA responses to short-term exposure to disinfection by-products in a swimming pool

BACKGROUND

Swimming in a chlorinated pool results in high exposure levels to disinfection by-products (DBPs), which have been associated with an increased risk of bladder cancer.

OBJECTIVES

By studying molecular responses at the blood transcriptome level we examined the biological processes associated with exposure to these compounds.

METHODS

Whole-genome gene expression and microRNA analysis was performed on blood samples collected from 43 volunteers before and 2h after 40min swimming in an indoor chlorinated pool (PISCINAII study). Exposure to THMs was measured in exhaled breath. Heart rate and kcal expenditure were measured as proxies for physical activity. Associations between exposure levels and gene expression were assessed using multivariate normal models (MVN), correcting for age, body mass index and sex. A Bonferroni threshold at 5% was applied.

RESULTS

MVN-models for the individual exposures identified 1778 genes and 23 microRNAs that were significantly associated with exposure to at least one DBP. Due to co-linearity it was not possible to statistically disentangle responses to DBP exposure from those related to physical activity. However, after eliminating previously reported transcripts associated with physical activity a large number of hits remained associated with DBP exposure. Among those, 9 were linked with bladder and 31 with colon cancer. Concordant microRNA/mRNA expressions were identified in association with DBP exposure for hsa-mir-22-3p and hsa-miR-146a-5p and their targets RCOR1 and TLR4, both related to colon cancer in association with DBP exposure.

CONCLUSIONS

Short-term exposure to low levels of DBPs shows genomics responses that may be indicative of increased cancer risk.

Long non-coding RNA SNHG1 regulates NOB1 expression by sponging miR-326 and promotes tumorigenesis in osteosarcoma

The long non-coding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) has been demonstrated to participate in the deterioration of many types of cancer. However, the underlying mechanisms of SNHG1-mediating functions in osteosarcoma (OS) have yet to be elucidated. In the present study, our results showed that SNHG1 was upregulated in OS tissues and cell lines, and high SNHG1 expression predicts poor overall survival of OS patients. Knockdown of SNHG1 inhibited cell growth and metastasis of OS in vitro and in vivo. Furthermore, our data demonstrated that there was reciprocal repression between SNHG1 and miR-326 which act as a tumor suppressor in OS cells, and exhibiting a strong negative relationship between SNHG1 and miR-326 expression in OS tissues. Additionally, we identified that SNHG1 increased human nin one binding protein (NOB1), an oncogene, through sponging miR-326 as competing endogenous RNA (ceRNA), finally prompting cell growth, migration and invasion in OS. Collectively, these findings not only uncovered that the SNHG1/miR-326/NOB1 signaling axis has a key role in OS progression but also suggested the potential application of SNHG1 and miR-326 as biomarkers in the OS diagnosis and treatment.

Low-level miR-646 in colorectal cancer inhibits cell proliferation and migration by targeting NOB1 expression

Aberrant expression of microRNA (miRNA) is important in the progression of various human cancers, however further investigation is required in order to fully elucidate mechanisms of and validate actions of endogenous non-coding RNAs. The present study demonstrated that the expression of miR-646 was downregulated in colorectal cancer tissues and cell lines. Notably, it was observed that miR-646, a tumor suppressor, inhibited colorectal cancer cell progression through directly targeting Nin one binding protein (NOB1) expression, which possesses anti-tumor properties in colorectal cancer. Furthermore, knockdown of NOB1 expression was responsible for the tumor-suppressive effect of miR-646. The findings suggest that miR-646 may act as a therapeutic target for the treatment of colorectal cancer.

MicroRNA-326 inhibits cell proliferation and invasion, activating apoptosis in hepatocellular carcinoma by directly targeting LIM and SH3 protein 1

Hepatocellular carcinoma (HCC) is the fifth-most common cancer and third leading cause of cancer-related deaths worldwide. Increasing evidence indicates that dysregulation of microRNAs is often observed in HCC, and has been extensively investigated in terms of cancer formation, progression, diagnosis, therapy, and prognosis. Recently, microRNA-326 (miR-326) has been demonstrated to play important roles in multiple types of human cancer. However, the expression pattern, clinical significance, roles and regulatory mechanisms of miR-326 in HCC have yet to be elucidated. In this study, miR-326 was frequently downregulated in HCC tissues and cell lines. Low miR-326 expression was significantly associated with the TNM stage, differentiation and lymph node metastasis of HCC patients. Further functional assays demonstrated that the recovered miR-326 expression inhibited HCC cell proliferation and invasion and activated cell apoptosis in vitro. In addition, LIM and SH3 protein 1 (LASP1) was identified as a direct target gene of miR-326 in HCC. Furthermore, LASP1 was upregulated in HCC tissues and cell lines. The expression level of LASP1 mRNA was inversely correlated with that of miR-326 in HCC tissues. Moreover, LASP1 silencing elicited effects similar to miR-326 overexpression on HCC cells, and LASP1 upregulation markedly reversed the effects of miR-326 overexpression on HCC cells. These results revealed that miR-326 suppressed the progression of HCC by directly targeting LASP1. Therefore, miR-326 may be used as a potential therapeutic target for the treatment of patients with HCC.

CDC42 expression is altered by dioxin exposure and mediated by multilevel regulations via AhR in human neuroblastoma cells

Emerging evidence has shown that dioxin causes dysregulation of microRNAs (miRs) in a variety of tissues or cells. However, little is known about dioxin effects on neuronal miRs expression. In the present study, 277 differentially expressed miRs were identified by miRs microarray analysis in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, at 10⁻¹⁰ M) treated SK-N-SH neuroblastoma cells. Among them, 53 miRs exhibited changes of more than 0.4-fold. Consistent with the microarray data, we verified the induction effect of TCDD on hsa-miR-608 expression, which is a primate-specific miR associated with brain functions. Bioinformatics analysis showed involvement of hsa-miR-608 in cytoskeleton organization, in which one of the hsa-miR-608 target genes, Cell Division Cycle 42 (CDC42), might play a role. We also confirmed induction of CDC42 expression by TCDD in SK-N-SH cells. TCDD induced the expression of CDC42 mRNA in hsa-miR-608 inhibitor transfected cells more obviously than in control cells, suggesting involvement of both transcriptional and post-transcriptional mechanisms in the TCDD-induced CDC42 regulation. Furthermore, CH223191, an antagonist of the aryl hydrocarbon receptor (AhR), counteracted TCDD-induced hsa-miR-608 and CDC42 expression. These results indicated that AhR not only mediates transcriptional induction of CDC42, but also hsa-miR-608-induced post-transcriptional regulation of CDC42 in dioxin treated neuroblastoma cells.

Inhibition of NOB1 by microRNA-330-5p overexpression represses cell growth of non-small cell lung cancer

MicroRNAs (miRNAs) play critical roles in the development and progression of various cancers, including non-small-cell lung cancer (NSCLC). Studies have suggested that miR-330-5p is involved in the progression of several cancers. However, the role of miR-330-5p in NSCLC remains unclear. We investigated the effect on and mechanism of miR-330-5p in the progression of NSCLC. We found that miR-330-5p was significantly downregulated in NSCLC tissues and cell lines as detected by real-time quantitative polymerase chain reaction (RT-qPCR). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), bromodeoxyuridine (BrdU), colony formation and cell cycle assays showed that overexpression of miR-330-5p markedly inhibited cell growth. Annexin V-FITC/PI and caspase-3 activity assays showed that overexpression of miR-330-5p significantly promoted cell apoptosis of NSCLC cells. Bioinformatics analysis and dual-luciferase reporter assays confirmed NIN/RPN12 binding protein 1 (NOB1) as a target gene of miR-330-5p. RT-qPCR and Western blot analysis showed that overexpression of miR-330-5p inhibited the expression of NOB1 as well as cyclin D1 and cyclin-dependent kinase 4 in NSCLC cells. Moreover, overexpression of NOB1 markedly reversed the miR‑330-5p-mediated inhibitory effect on NSCLC cell growth. Correlation analysis showed that miR‑330-5p expression was inversely correlated with NOB1 mRNA expression in NSCLC tissues. Taken together, our results indicate that miR-330-5p inhibits NSCLC cell growth through downregulation of NOB1 expression. Our study suggests that miR-330-5p may serve as a potential therapeutic target for the treatment of NSCLC.

β-arrestin1-mediated acetylation of Gli1 regulates Hedgehog/Gli signaling and modulates self-renewal of SHH medulloblastoma cancer stem cells

Background

Aberrant Sonic Hedgehog/Gli (Hh/Gli) signaling pathway is a critical regulator of Sonic hedgehog medulloblastoma (SHH-MB). Cancer stem cells (CSCs), thought to be largely responsible for tumor initiation, maintenance, dissemination and relapse, have been identified in SHH-MB. Since we previously demonstrated that Hh/Gli signaling controls CSCs features in SHH-MB and that in these tumors miR-326 is down regulated, here we investigated whether there is a functional link between Hh/Gli signaling and miR-326.

Methods

We evaluated β-arrestin1 (Arrb1) and its intragenic miR-326 levels in CSCs derived from SHH-MB. Subsequently, we modulated the expression of Arrb1 and miR-326 in CSCs in order to gain insight into their biological role. We also analyzed the mechanism by which Arrb1 and miR-326 control Hh/Gli signaling and self-renewal, using luciferase and protein immunoprecipitation assays.

Results

Low levels of Arrb1 and miR-326 represent a feature of CSCs derived from SHH-MB. We observed that re-expression of Arrb1 and miR-326 inhibits Hh/Gli signaling pathway at multiple levels, which cause impaired proliferation and self-renewal, accompanied by down regulation of Nanog levels. In detail, miR-326 negatively regulates two components of the Hh/Gli pathway the receptor Smoothened (Smo) and the transcription factor Gli2, whereas Arrb1 suppresses the transcriptional activity of Gli1, by potentiating its p300-mediated acetylation.

Conclusions

Our results identify a new molecular mechanism involving miR-326 and Arrb1 as regulators of SHH-MB CSCs. Specifically, low levels of Arrb1 and miR-326 trigger and maintain Hh/Gli signaling and self-renewal.

MicroRNA-326 suppresses the proliferation, migration and invasion of cervical cancer cells by targeting ELK1

Although microRNAs (miRNAs or miRs) are able to function as oncogenes or tumor suppressors, the role of miR-326 in regulating human cervical cancer cells remains unclear. In the present study, the expression of miR-326 was identified to be downregulated in cervical cancer cell lines and primary tumor samples, and the overexpression of miR-326 decreased cell proliferation, migration and invasion in cervical cell lines. Bioinformatics prediction and experimental validation results revealed that the function of miR-326 was achieved by targeting and repressing ETS domain-containing protein Elk-1 (ELK1) expression. ELK1 was targeted directly by miR-326, which was downregulated in human cervical cancer tissues compared with that in adjacent normal tissues. The results of the present study suggest that miR-326, a potential tumor suppressor, may be used in the treatment of cervical cancer.

Hsa-miR-326 targets CCND1 and inhibits non-small cell lung cancer development

Hsa-miRNA-326 (miR-326) has recently been discovered having anticancer efficacy in different organs. However, the role of miR-326 on non-small cell lung cancer (NSCLC) is still ambiguous. In this study, we investigated the role of miR-326 on the development of NSCLC. The results indicated that miR-326 was significantly down-regulated in primary tumor tissues and very low levels were found in NSCLC cell lines. Ectopic expression of miR-326 in NSCLC cell lines significantly suppressed cell growth as evidenced by cell viability assay, colony formation assay and BrdU staining, through inhibition of cyclin D1, cyclin D2, CDK4 and up-regulation of p57(Kip2) and p21(Waf1/Cip1). In addition, miR-326 induced apoptosis, as indicated by concomitantly with up-regulation of key apoptosis protein cleaved caspase-3, and down-regulation of anti-apoptosis protein Bcl2. Moreover, miR-326 inhibited cellular migration and invasiveness through inhibition of matrix metalloproteinases (MMP)-7 and MMP-9. Further, oncogene CCND1 was revealed to be a putative target of miR-326, which was inversely correlated with miR-326 expression in NSCLC. Taken together, our results demonstrated that miR-326 played a pivotal role on NSCLC through inhibiting cell proliferation, migration, invasion, and promoting apoptosis by targeting oncogenic CCND1.

PI3 kinase pathway regulated miRNome in glioblastoma: identification of miR-326 as a tumour suppressor miRNA

Background

Glioblastomas (GBM) continue to remain one of the most dreaded tumours that are highly infiltrative in nature and easily preclude comprehensive surgical resection. GBMs pose an intricate etiology as they are being associated with a plethora of genetic and epigenetic lesions. Misregulation of the PI3 kinase pathway is one of the most familiar events in GBM. While the PI3 kinase signalling regulated pathways and genes have been comprehensively studied, its impact on the miRNome is yet to be explored. The objective of this study was to elucidate the PI3 kinase pathway regulated miRNAs in GBM.

Methods

miRNA expression profiling was conducted to monitor the differentially regulated miRNAs upon PI3 kinase pathway abrogation. qRT-PCR was used to measure the abundance of miR-326 and its host gene encoded transcript. Proliferation assay, colony suppression assay and wound healing assay were carried out in pre-miR transfected cells to investigate its role in malignant transformation. Potential targets of miR-326 were identified by transcriptome analysis of miR-326 overexpressing cells by whole RNA sequencing and selected targets were validated. Several publically available data sets were used for various investigations described above.

Results

We identified several miRNA that were regulated by PI3 kinase pathway. miR-326, a GBM downregulated miRNA, was validated as one of the miRNAs whose expression was alleviated upon abrogation of the PI3 kinase pathway. Overexpression of miR-326 resulted in reduced proliferation, colony suppression and hindered the migration capacity of glioma cells. Arrestin, Beta 1 (ARRB1), the host gene of miR-326, was also downregulated in GBM and interestingly, the expression of ARRB1 was also alleviated upon inhibition of the PI3 kinase pathway, indicating similar regulation pattern. More importantly, miR-326 exhibited a significant positive correlation with ARRB1 in terms of its expression. Transcriptome analysis upon miR-326 overexpression coupled with integrative bioinformatics approach identified several putative targets of miR-326. Selected targets were validated and interestingly found to be upregulated in GBM.

Conclusions

Taken together, our study uncovered the PI3 kinase regulated miRNome in GBM. miR-326, a PI3 kinase pathway inhibited miRNA, was demonstrated as a tumour suppressor miRNA in GBM.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-016-0557-8) contains supplementary material, which is available to authorized users.

Evaluation of plasma microRNA levels to predict insensitivity of patients with advanced lung adenocarcinomas to pemetrexed and platinum

Pemetrexed combined with platinum is a first-line therapy used to treat patients with advanced non-small cell lung cancer (NSCLC) that exhibit negative or unknown epidermal growth factor receptor (EGFR) mutational status or anaplastic lymphoma kinase (ALK) rearrangements. Lung adenocarcinoma (LAC) is the primary type of NSCLC. In order to prevent overtreatment, it is necessary to identify patients with LAC who may not benefit from certain chemotherapies. Patients recruited in the present study (n=129) were diagnosed with advanced LAC and received first-line pemetrexed and platinum-based chemotherapy. A microRNA (miR) microarray was used to screen the plasma miR expression profiles in a screening set of eight patients prior to and following treatment. Specifically, plasma miR-25, miR-21, miR-27b, miR-326, miR-483-5p and miR-920 were selected for reverse transcription-quantitative polymerase chain reaction analysis in a training set (n=44) prior to treatment. The screening and training set patients were all non-smokers with no prior history of serious or chronic disease. The ∆∆Cq values of these miRs were compared between the group that showed benefit from pemetrexed and platinum treatment and the group that did not. Consequently, the ∆∆Cq values of miR-25, miR-21, miR-27b and miR-326 were further determined in a validation set (n=77). The results of the present study demonstrate that plasma expression levels of miR-25, miR-21, miR-27b and miR-326, in the training and validation sets prior to treatment, were significantly different between the benefit and non-benefit groups (P≤0.001). The expression of miR-25, miR-21, miR-27b and miR-326 was upregulated in the non-benefit group and this elevation was positively correlated with decreased progression-free survival (PFS; P≤0.001). In addition, the predictive power of each miR was evaluated through receiver operating characteristic curves, in which miR-25 exhibited the highest degree of accuracy (area under the curve, 0.926; 95% confidence interval, 0.881-0.971). These results indicate that overexpression of plasma miR-25, miR-21, miR-27b and miR-326, prior to treatment, in patients with advanced LAC is predictive of non-benefit from first-line pemetrexed and platinum-based chemotherapy, and is associated with decreased PFS. Among these four miRs, miR-25 exhibited the highest degree of accuracy in predicting insensitivity, suggesting it is the most promising biomarker.

Knockdown of long non-coding RNA HOTAIR inhibits malignant biological behaviors of human glioma cells via modulation of miR-326

Glioma is the most common and aggressive primary adult brain tumor. Long non-coding RNAs (lncRNAs) have important roles in a variety of biological properties of cancers. Here, we elucidated the function and the possible molecular mechanisms of lncRNA HOTAIR in human glioma U87 and U251 cell lines. Quantitative RT-PCR demonstrated that HOTAIR expression was up-regulated in glioma tissues and cell lines. Knockdown of HOTAIR exerted tumor-suppressive function in glioma cells. Further, HOTAIR was confirmed to be the target of miR-326 and miR-326 mediated the tumor-suppressive effects of HOTAIR knockdown on glioma cell lines. Moreover, over-expressed miR-326 reduced the FGF1 expression which played an oncogenic role in glioma by activating PI3K/AKT and MEK 1/2 pathways. In addition, the in vivo studies also supported the above findings. Taken together, knockdown of HOTAIR up-regulated miR-326 expression, and further inducing the decreased expression of FGF1, these results provided a comprehensive analysis of HOTAIR-miR-326-FGF1 axis in human glioma and provided a new potential therapeutic strategy for glioma treatment.

MicroRNAs in glioblastoma multiforme pathogenesis and therapeutics

Glioblastoma multiforme (GBM) is the most common and lethal cancer of the adult brain, remaining incurable with a median survival time of only 15 months. In an effort to identify new targets for GBM diagnostics and therapeutics, recent studies have focused on molecular phenotyping of GBM subtypes. This has resulted in mounting interest in microRNAs (miRNAs) due to their regulatory capacities in both normal development and in pathological conditions such as cancer. miRNAs have a wide range of targets, allowing them to modulate many pathways critical to cancer progression, including proliferation, cell death, metastasis, angiogenesis, and drug resistance. This review explores our current understanding of miRNAs that are differentially modulated and pathologically involved in GBM as well as the current state of miRNA-based therapeutics. As the role of miRNAs in GBM becomes more well understood and novel delivery methods are developed and optimized, miRNA-based therapies could provide a critical step forward in cancer treatment.

High Expression of RIOK2 and NOB1 Predict Human Non-small Cell Lung Cancer Outcomes

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related mortality worldwide. However, there is a shortage of suitable diagnostic markers for early stages of NSCLC, and therapeutic targets are limited. Right open reading frame (Rio) kinase 2 (RIOK2) and Nin one binding (NOB1) protein are important accessory factors in ribosome assembly and are highly expressed in malignant tumours; moreover, they interact with each other. However, the RIOK2 expression profile and its clinical significance as well as NOB1's mechanism in NSCLC remain unknown. In this study, NSCLC cell lines and 15 NSCLC tumour tissues (paired with adjacent normal lung tissues) were collected for a real-time quantitative PCR (RT-qPCR) analysis. In addition, 153 NSCLC cases and 27 normal lung tissues were used in an immunohistochemical analysis to evaluate the RIOK2 and NOB1 expression profiles, their clinicopathological factors in NSCLC and their correlations with prognoses. RIOK2 and NOB1 were highly expressed in NSCLC cells and tissues, and their expression profiles were significantly associated with the Tumour Node Metastasis (TNM) clinical stage, lymph node metastasis, and differentiation. RIOK2 expression was correlated with NOB1. The results suggested that simultaneously determining the expression of RIOK2 and NOB1 will improve the diagnostic rate in early stages of NSCLC. Moreover, RIOK2 and NOB1 might be potential targets for NSCLC therapy.

MiR-192 suppresses the tumorigenicity of prostate cancer cells by targeting and inhibiting nin one binding protein

Nin one binding (NOB1) protein has been identified as an oncogene in various human cancers, including prostate cancer. MicroRNAs (miRs) have also been recognized as novel regulatory molecules of gene expression. The present study aimed to discover potential miRs that target NOB1 and regulate NOB1 expression in prostate cancer. miR-192, which is an important regulator of numerous cancers, was found to be significantly downregulated in prostate cancer cells. Moreover, we noted that miR-192 overexpression markedly inhibited the proliferation, colony‑forming ability, and migratory capacity of the prostate cancer cells. miR-192 overexpression also induced cell cycle arrest in the G1 phase, as shown by flow cytometry. Bioinformatics analysis results revealed that NOB1 was a possible candidate target gene of miR-192. This discovery was further verified through dual‑luciferase reporter assay, RT-qPCR, and western blot analysis. We suggest that miR-192 directly regulates the mRNA and protein expression of NOB1. Furthermore, miR-192 inhibited the expression of p38 mitogen-activated protein kinase. The results of our study indicated that miR-192 negatively regulated NOB1 expression and impaired the tumorigenicity of prostate cancer cells. Therefore, we suggest that targeting miR-192 and NOB1 is a novel strategy which will assist in the development of new therapeutics that will be used in the future to prevent and treat prostate cancer.

Implications of mitogen-activated protein kinase signaling in glioma

Gliomas are the most common primary central nervous system tumors. Gliomas originate from astrocytes, oligodendrocytes, and neural stem cells or their precursors. According to WHO classification, gliomas are classified into four different malignant grades ranging from grade I to grade IV based on histopathological features and related molecular aberrations. The induction and maintenance of these tumors can be attributed largely to aberrant signaling networks. In this regard, the mitogen-activated protein kinase (MAPK) network has been widely studied and is reported to be severely altered in glial tumors. Mutations in MAPK pathways most frequently affect RAS and B-RAF in the ERK, c-Jun N-terminal kinase (JNK), and p38 pathways leading to malignant transformation. Also, it is linked to both inherited and sequential accumulations of mutations that control receptor tyrosine kinase (RTK)-activated signal transduction pathways, cell cycle growth arrest pathways, and nonresponsive cell death pathways. Genetic alterations that modulate RTK signaling can also alter several downstream pathways, including RAS-mediated MAP kinases along with JNK pathways, which ultimately regulate cell proliferation and cell death. The present review focuses on recent literature regarding important deregulations in the RTK-activated MAPK pathway during gliomagenesis and progression.

Downregulation of NOB1 inhibits proliferation and promotes apoptosis in human oral squamous cell carcinoma

NIN1/RPN12 binding protein 1 homolog (NOB1) facilitates the maturation of the 20S proteasome and is then degraded by 26S proteasome to complete 26S proteasome biogenesis. It also accompanies the pre-40S ribosomes during nuclear export and is cleaved at D-site of 20S pre-rRNA to form mature 18S rRNA in growing cells. NOB1 was reported to be involved in the development of several types of cancer. However, the role of NOB1 in oral squamous cell carcinoma (OSCC) has not been addressed. In the present study, the expression of NOB1 in 50 OSCC patients with different genders, ages, TNM and pathological grades was detected using immunohistochemistry and western blotting. A loss-of‑function study was carried out by the lentivirus‑mediated siRNA knockdown of NOB1 in the CAL27 and TCA-8113 OSCC cell lines. The results showed that, NOB1 expression increased with pathological grades. In the CAL27 and TCA-8113 cell lines, knockdown of NOB1 in OSCC cells decreased cell proliferation, colony formation, increased cell apoptosis and also induced cell cycle arrest in the S phase. The results suggested that NOB1 is important in OSCC development and serves as a candidate indicator of aggressiveness and a therapeutic target of OSCC.

MicroRNA‑133a and microRNA‑326 co‑contribute to hepatocellular carcinoma 5‑fluorouracil and cisplatin sensitivity by directly targeting B‑cell lymphoma‑extra large

Chemotherapy is one of the most common treatments used for hepatocellular carcinoma (HCC), which effectively improves outcome and reduces tumor recurrence. However, the drug resistance mechanisms involved in chemotherapy, which is the predominant challenge in HCC treatment, remain to be fully elucidated. Therefore, there is an urgent requirement for the identification of novel therapeutic strategies or drugs. MicroRNAs (miRs) have become an area of interest, and in the present study, the effects of miR‑133a and miR‑326 on HepG2 cells, and their function on B‑cell lymphoma‑extra large (Bcl‑xl) in HepG2 cells were investigated. Using computational programs, Bcl‑xl was predicted as the common target gene of miR‑133a and miR‑326. A dual‑luciferase reporter assay was used to verify the target genes of miRs. The mRNA and protein levels of Bcl‑xl were observed to be downregulated following transfection with miR‑133a or miR‑326 mimics. Combining miR‑133a or miR‑326 with 5‑fluorouracil (5‑FU) or cisplatin (DDP) resulted in increased cell death. The results of the present study indicated that miR‑133a, miR‑326 and Bcl‑xl acted protectively against the apoptosis, induced by 5‑FU or DDP, in HepG2 cells. This suggested the potential use of miRs either as ancillary anti‑cancer drugs or as anti‑cancer drugs themselves.