miR-326 Inhibits Gastric Cancer Cell Growth Through Downregulating NOB1

Elucidating the Role of miRNA-326 Modulating Hedgehog Signaling in Pancreatic Carcinoma

BACKGROUND AND AIM

Pancreatic ductal adenocarcinoma (PDAC) is one of the lethal malignancies worldwide characterized by poor prognosis. MicroRNAs (miRNAs) function as the key regulators in carcinogenesis and may act as noninvasive biomarkers in various malignancies including PDAC. The present study aimed to elucidate the role of miR-326, a known modulator of hedgehog (Hh) pathway in PDAC.

MATERIALS AND METHODS

miR-326 circulating levels were assessed in 105 PDAC patients, 31 with chronic pancreatitis (CP) and 36 healthy controls by quantitative Polymerase chain reaction. The expression of miR-326 and smoothened (SMO) was checked in surgical PDAC tissue. SMO protein expression was analyzed by immunohistochemistry in different groups. Finally, the role of miR-326 as a modulator of Hh pathway was assessed in vitro.

RESULTS

Our results demonstrate that miR-326 is downregulated in both blood and tissue of PDAC patients as compared with controls. In contrast, the target gene/protein expression of SMO is upregulated in PDAC. Moreover, the tumor stromal expression of SMO was found to be clinically associated with lymph-node metastasis and vascular encasement in PDAC. Overexpression of miR-326 in Panc1 cell line was found to induce downregulation of SMO suggesting the tumor suppressor role of miR-326 in PDAC.

CONCLUSIONS

Taken together, miR-326 acts as a tumor suppressor in PDAC by modulating Hh pathway. It may be a promising target for the development of efficient drug therapies for the treatment of PDAC.

Lnc-HIBADH-4 Regulates Autophagy-Lysosome Pathway in Amyotrophic Lateral Sclerosis by Targeting Cathepsin D

Amyotrophic lateral sclerosis (ALS) is the most prevalent and lethal class of severe motor neuron diseases (MND) with no efficacious treatment. The pathogenic mechanisms underlying ALS remain unclear. Nearly 90% of patients exhibit sporadic onset (sALS). Therefore, elucidating the pathophysiology of ALS is imperative. Long non-coding RNA (lncRNA) is a large class of non-coding RNAs that regulate transcription, translation, and post-translational processes. LncRNAs contribute to the pathogenesis of diverse neurodegenerative disorders and hold promise as targets for interference in the realm of neurodegeneration. However, the mechanisms of which lncRNAs are involved in ALS have not been thoroughly investigated. We identified and validated a downregulated lncRNA, lnc-HIBADH-4, in ALS which correlated with disease severity and overall survival. Lnc-HIBADH-4 acted as a "molecular sponge" regulating lysosomal function through the lnc-HIBADH-4/miR-326/CTSD pathway, thereby impacting autophagy-lysosome dynamics and the levels of cell proliferation and apoptosis. Therefore, this study discovered and revealed the role of lnc-HIBADH-4 in the pathogenesis of ALS. With further research, lnc-HIBADH-4 is expected to provide a new biomarker in the diagnosis and treatment of ALS.

Integrated analysis using ToppMiR uncovers altered miRNA- mRNA regulatory networks in pediatric hepatocellular carcinoma-A pilot study

BACKGROUND

Pediatric hepatocellular carcinoma (HCC) is a group of liver cancers whose mechanisms behind their pathogenesis and progression are poorly understood.

AIM

We aimed to identify alterations in the expression of miRNAs and their putative target mRNAs in not only tumor tissues of patients with pediatric HCC but also in corresponding non-tumorous background livers by using liver tissues without underlying liver disease as a control.

METHODS AND RESULTS

We performed a small-scale miRNA and mRNA profiling of pediatric HCC (consisting of fibrolamellar carcinoma [FLC] and non-FLC HCC) and paired liver tissues to identify miRNAs whose expression levels differed significantly from control livers without underlying liver disease. ToppMiR was used to prioritize both miRNAs and their putative target mRNAs in a gene-annotation network, and the mRNA profile was used to refine the prioritization. Our analysis generated prioritized lists of miRNAs and mRNAs from the following three sets of analyses: (a) pediatric HCC versus control; (b) FLC versus control; and (c) corresponding non-tumorous background liver tissues from the same patients with pediatric HCC versus control. No liver disease liver tissues were used as the control group for all analyses. Many miRNAs whose expressions were deregulated in pediatric HCC were consistent with their roles in adult HCC and/or other non-hepatic cancers. Our gene ontology analysis of target mRNAs revealed enrichment of biological processes related to the sustenance and propagation of cancer and significant downregulation of metabolic processes.

CONCLUSION

Our pilot study indicates that alterations in miRNA-mRNA networks were detected in not only tumor tissues but also corresponding non-tumorous liver tissues from patients with pediatric HCC, suggesting multi-faceted roles of miRNAs in disease progression. Our results may lead to novel hypotheses for future large-scale studies.

Long non-coding RNA LINC01270 is an onco-promotor in lung adenocarcinoma by upregulating LARP1 via sponging miR-326

Accumulating evidence have proved the key role of long non-coding RNA in lung adenocarcinoma (LUAD) progression. Bioinformatics analysis is used to seek the differentially expressed lncRNA LINC01270 from TCGA database. The overexpression of LINC01270 was then verified in LUAD tumor tissues and cell lines by qRT-PCR. LINC01270 knockdown resulted in impaired cell proliferative and invasive ability via CCK-8 assay, EdU assay, colony formation assay, transwell assay, while aberrant upregulation of LINC01270 led to enhanced cell growth and invasion. Moreover, LINC01270 was found inhibiting miR-326 and thereby overexpressing the abundance of LARP1 to promote LUAD development via PI3K/AKT pathway. It was also proved that LINC01270 knockdown could suppress LUAD tumor growth in vivo. All of these findings demonstrate thatLINC01270 is a tumor promotor in LUAD via enhancing LARP1 expressed by sponging miR-326 to facilitate the development of LUAD. LINC01270 play a significant role in LUAD, which could serve as biomarkers for early diagnosis and a novel targeted remedy.

LncRNA LINC01270 aggravates the progression of gastric cancer through modulation of miR-326/EFNA3 axis

Gastric cancer (GC) is lethal malignancy, which is associated with high mortality. Long noncoding RNA LINC01270 has been identified to act as a potential oncogene in several cancers. However, its role and related regulatory mechanism in GC are yet to be illustrated. The levels of lncRNA LINC01270, miR-326, and EphrinA3 (EFNA3) were assessed by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Cell counting kit-8 (CCK-8) and colony formation assays were applied for analyzing cell proliferation. Transwell assay was used for measuring cellular migration and invasion. Western blot analysis was employed for evaluating the protein levels. Luciferase reporter and RNA pull-down assays were utilized to verify the binding ability between LINC01270 (or EFNA3) and miR-326. Our findings indicated that LINC01270 expression was significantly up-regulated in GC tissues and cell lines. Additionally, LINC01270 knockdown attenuated GC progression through inhibiting cell proliferation, migration, and invasion. Functional experiments identified that lncRNA LINC01270 could positively regulate EFNA3 expression by serving as a competing endogenous RNA (ceRNA) for miR-326. Through rescue assays, inhibition of GC progression caused by LINC01270 suppression was found to be reversed by the application of miR-326 inhibitor or EFNA3 overexpression. Overall, our work demonstrated that lncRNA LINC01270 can accelerate cell proliferation, migration, and invasion via modulating miR-326/EFNA3 axis. These findings might implicate the potential role of lncRNA LINC01270 in GC treatment.

Circular RNA Circ_0008043 promotes the proliferation and metastasis of hepatocellular carcinoma cells by regulating the microRNA (miR)-326/RAB21 axis

Circular RNAs (circRNAs) are non-coding RNAs with covalently closed structures that modulate the progression of hepatocellular carcinoma (HCC). Here, we explored whether circ_0008043 regulated the biological function of HCC cells. Quantitative real-time polymerase chain reaction (qPCR) was used to detect circ_0008043, microRNA (miR)-326, and RAB21 levels. Expression of E-cadherin, N-cadherin, and vimentin was assessed using qPCR. Cell proliferation, migration, and invasion were evaluated using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, colony formation, and transwell assays. Xenograft tumors were used to evaluate cell growth in vivo. The interaction between miR-326 and circ_0008043 or RAB21 was assessed using dual-luciferase reporter analysis and RNA pull-down analysis. The data illustrated that circ_0008043 and RAB21 were highly expressed, while miR-326 was expressed at less levels in HCC tissues and cells. Interfering with circ_0008043 suppressed cellular proliferation, migration, invasion, and cell growth. Circ_0008043 was confirmed to be an miR-326 sponge that targets RAB21. Rescue experiments showed that inhibiting miR-326 abrogated the effect induced by knockdown of circ_0008043, and overexpressed RAB21 abolished the effect induced by miR-326 overexpression. In summary, silencing of circ_0008043 impeded HCC progression by regulating the miR-326/RAB21 axis. These data suggest that circ_0008043 may have clinical value in the treatment of HCC.

hsa_circ_0139402 Promotes Bladder Cancer Progression by Regulating hsa-miR-326/PAX8 Signaling

Background

Bladder cancer (BC) is a malignant and common malignant tumors. However, the prognosis of most patients with bladder cancer is still poor, and it is particularly important to identify early tumor diagnostic and treatment targets.

Materials and Methods

High-throughput sequencing was used to evaluate the expression level of circRNA in bladder cancer tissue. MTT assay, wound healing assay, and transwell assay were used to detect the cancer cells' proliferation, migration, and invasion affected by hsa_circ_0139402. The possible miRNA targets of hsa_circ_0139402 and downstream genes were detected by bioinformatics methods and dual-luciferase reporting experiment. FISH was used to observe their interaction.

Results

High-throughput sequencing result showed that the expression of hsa_circ_0139402 was highest in BC tissues and increased in metastatic tissues compared to that of nonmetastatic tissues. MTT assay, wound healing assay, and transwell assay revealed that sh-hsa_circ_0139402 could suppress BC cells' proliferation, invasion, and migration. Bioinformatics analysis, dual-luciferase reporter, and RIP assay showed that hsa_circ_0139402 can bind to hsa-miR-326, and PAX8 is a direct target of hsa-miR-326 in BC cell. Further, cytological studies found that hsa_circ_0139402 enhances BC cells' proliferation, migration, and invasion by targeting PAX8 via hsa-miR-326.

Conclusion

hsa_circ_0139402 plays a oncogene in BC and that can effectively promote cell proliferation, migration, invasion, and EMT by targeting Paired Box Protein Pax-8 (PAX8) via hsa-miR-326 and provides a potential therapeutic target for BC patients.

Functions of lncRNA DUXAP8 in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) poses a serious threat to public health due to its significant morbidity and mortality rates. The processes of NSCLC formation and development are quite complex and involve numerous regulatory biomolecules. Long non-coding RNAs (lncRNAs) have attracted attention since they have been found to play critical roles in the tumorigenesis of various human malignancies. Recently, double homeobox A pseudogene 8 (DUXAP8) was identified as an oncogenic lncRNA that is overexpressed in different tumor types. In NSCLC, high expression of DUXAP8 is associated with poor prognosis in patients. The regulatory mechanism underlying the oncogenic effects of DUXAP8 can be divided into transcriptional level and post-transcriptional level. DUXAP8 promotes proliferation, epithelial-mesenchymal transition, and aerobic glycolysis in NSCLC cells. Moreover, DUXAP8 shows potential for the diagnosis and treatment of NSCLC. Herein, we review the molecular mechanisms underlying the DUXAP8-mediated phenotypes of NSCLC as well as its potential clinical applications.

Long noncoding RNA FAM225A promotes the malignant progression of gastric cancer through the miR-326/PADI2 axis

Gastric cancer (GC) is a global health problem and further studies of its molecular mechanisms are needed to identify effective therapeutic targets. Although some long noncoding RNAs (lncRNAs) have been found to be involved in the progression of GC, the molecular mechanisms of many GC-related lncRNAs remain unclear. In this study, a series of in vivo and in vitro assays were performed to study the relationship between FAM225A and GC, which showed that FAM225A levels were correlated with poor prognosis in GC. Higher FAM225A expression tended to be correlated with a more profound lymphatic metastasis rate, larger tumor size, and more advanced tumor stage. FAM225A also promoted gastric cell proliferation, invasion, and migration. Further mechanistic investigation showed that FAM225A acted as a miR-326 sponge to upregulate its direct target PADI2 in GC. Overall, our findings indicated that FAM225A promoted GC development and progression via a competitive endogenous RNA network of FAM225A/miR-326/PADI2 in GC, providing insight into possible therapeutic targets and prognosis of GC.

Hsa_circ_0020850 promotes the malignant behaviors of lung adenocarcinoma by regulating miR-326/BECN1 axis

Background

Circular RNAs (circRNAs) are a novel type of endogenous RNAs and play vital roles in lung adenocarcinoma. However, the function and underlying mechanism of circ_0020850 in lung adenocarcinoma remain unknown.

Methods

The levels of circ_0020850, microRNA-326 (miR-326), and Beclin1 (BECN1) were analyzed by real-time quantitative polymerase chain reaction and western blot analyses. The migration and invasion were determined by wound healing and transwell assays, respectively. Colony formation assay was used to assess cell proliferation ability. The angiogenic ability was analyzed by Matrigel angiogenesis assay. The apoptosis rate was calculated by flow cytometry assay. Dual-luciferase reporter, RNA immunoprecipitation (RIP), and RNA pull-down assays were conducted to confirm the interaction relationship among circ_0020850, miR-326, and BECN1. A xenograft mice model was established to assess the role of circ_0020850 in vivo.

Results

We found that circ_0020850 was obviously overexpressed in lung adenocarcinoma tissues and cells. Knockdown of circ_0020850 inhibited migration, invasion, proliferation, and angiogenesis but induced apoptosis in lung adenocarcinoma cells in vitro, as well as curbed tumor growth in vivo. MiR-326 was a target of circ_0020850, and knockdown of miR-326 abolished the suppression effect of circ_0020850 on the malignant behaviors of lung adenocarcinoma cells. Additionally, miR-326 could negatively regulate BECN1 expression, thereby regulating lung adenocarcinoma cell phenotypes. Importantly, circ_0020850 could directly bind to miR-326 and thus relieve miR-326-mediated inhibition on BECN1.

Conclusion

Circ_0020850 promoted the malignant development of lung adenocarcinoma by regulating miR-326/BECN1 axis, indicating that circ_0020850 might serve as a promising target for the diagnosis and treatment of lung adenocarcinoma patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02480-3.

The construction and analysis of ceRNA network and patterns of immune infiltration in lung adenocarcinoma

BACKGROUND

Competitive Endogenous RNA (ceRNA) may be closely associated with tumor progression. However, studies on ceRNAs and immune cells in LUAD are scarce.

METHOD

The profiles of gene expression and clinical data of LUAD patients were extracted from the TCGA database. Bioinformatics methods were used to evaluate differentially-expressed genes (DEGs) and to form a ceRNA network. Preliminary verification of clinical specimens was utilized to detect the expressions of key biomarkers at the tissues. Cox and Lasso regressions were used to identify key genes, and prognosis prediction nomograms were formed. The mRNA levels of 9 genes in the risk score model in independent clinical LUAD samples were detected by qRT-PCR. The interconnection between the risk of cancer and immune cells was evaluated using the CIBERSORT algorithm, while the conformation of notable tumor-infiltrating immune cells (TIICs) in the LUAD tissues of the high and low risk groups was assessed using the RNA transcript subgroup in order to identify tissue types. Finally, co-expression study was used to examine the interconnection between the key genes in the ceRNA networks and the immune cells.

RESULT

A ceRNA network of 115 RNAs was established, and nine key genes were identified to construct a Cox proportional-hazard model and create a prognostic nomogram. This risk-assessment model might serve as an independent factor to forecast the prognosis of LUAD, and it was consistent with the preliminary verification of clinical specimens. Survival analysis of clinical samples further validated the potential value of high risk groups in predicting LUAD prognosis. Five immune cells were identified with significant differences in the LUAD tissues of the high and low risk groups. Besides, two pairs of biomarkers associated with the growth of LUAD were found, i.e., E2F7 and macrophage M1 (R = 0.419, p = 1.4e- 08) and DBF4 and macrophage M1 (R = 0.282, p < 2.2 e- 16).

CONCLUSION

This study identified several important ceRNAs, i.e. (E2F7 and BNF4) and TIICs (macrophage M1), which might be related to the development and prognosis of LUAD. The established risk-assessment model might be a potential tool in predicting LUAD of prognosis.

LncRNA PCAT6 activated by SP1 facilitates the progression of breast cancer by the miR-326/LRRC8E axis

Breast cancer is an aggressive malignancy with high morbidity in females worldwide. Extensive studies reveal that long noncoding RNAs (lncRNAs) are abnormally expressed and act as key regulators in various cancers, including breast cancer. In this work, we investigated the role and regulatory mechanism of lncRNA prostate cancer-associated transcript 6 (PCAT6) in breast cancer progression. Our findings revealed that PCAT6 was overexpressed in breast cancer tissues and cell lines. Furthermore, elevation of PCAT6 reflected an adverse prognosis of patients. Functional experiments indicated that PCAT6 knockdown hampered cell proliferation, facilitated apoptosis and cell cycle arrest in vitro, and inhibited tumor growth in vivo. We also found that the transcription factor SP1 could bind to the PCAT6 promoter and promoted its expression. Subsequently, it was verified that PCAT6 was a molecular sponge for microRNA-326 (miR-326), and the leucine-rich repeat containing the eight family member E (LRRC8E) was a direct target of miR-326. Rescue assays revealed that LRRC8E overexpression attenuated the suppressive effect of PCAT6 knockdown on cellular progression of breast cancer. In summary, this study demonstrated that SP1-activated PCAT6 promoted the malignant behaviors of breast cancer cells by regulating the miR-326/LRRC8E axis.

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.

Mechanisms of circular RNA circ_0066147 on pancreatic cancer progression

Background

The purpose of the study was to explore the precise parts of circ_0066147 (circular RNA [circRNA] scm-like with four mbt domains 1, circSFMBT1) in pancreatic cancer (PC) progression.

Methods

Ribonuclease R assay was used to confirm the stability of circ_0066147. circ_0066147, miR-326 and E2F transcription factor 2 (E2F2) expression levels was detected by quantitative reverse-transcription polymerase chain reaction or Western blot. Cell proliferation, apoptosis, migration and invasion abilities were assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide, flow cytometry, wound-healing and transwell assays, respectively. Targeted relationships among circ_0066147, miR-326 and E2F2 were verified by the dual-luciferase reporter or RNA pull-down assay.

Results

circ_0066147 expression was upregulated in PC tissues and cells. circ_0066147 knockdown inhibited PC cell proliferation, migration, invasion and enhanced apoptosis in vitro, as well as weakened tumor growth in vivo. Mechanistically, circ_0066147 directly targeted miR-326 and circ_0066147 modulated E2F2 expression by miR-326. miR-326 mediated the regulation of circ_0066147 in PC cell behaviors in vitro. Furthermore, E2F2 was a functional target of miR-326 in modulating PC cell behaviors in vitro.

Conclusion

circ_0066147 regulated PC malignant progression in part depending on the miR-326/E2F2 axis, illuminating circ_0066147 was a potential prognostic marker and therapeutic target for PC management.

circATP2B1 Promotes Aerobic Glycolysis in Gastric Cancer Cells Through Regulation of the miR-326 Gene Cluster

The discovery of circular RNA (circRNA) enormously complimented the repertoire of traditional gene expression theory. As a type of endogenous noncoding RNA, circRNA participates in the occurrence of many kinds of tumors in addition to regulating their development. The Warburg effect (aerobic glycolysis is taken with priority for cancer cells instead of oxidative phosphorylation) is one of the most important factors involved in the excessive proliferation of gastric cancer cells. Our data showed that circRNA circATP2B1 (also called hsa_circ_000826) was overexpressed in gastric cancer tissues instead of linear ATP2B1 mRNA, and it promoted aerobic glycolysis in gastric cancer cells. Bioinformatic Gene Ontology analysis showed that the potential downstream targets of circATP2B1 include the microRNA miR-326 gene cluster (miR-326-3p/miR-330-5p), which is functionally focused on cell growth and metabolic processes. The expressions of miR-326-3p/miR-330-5p were downregulated in gastric cancer, and circATP2B1 functionally targeted miR-326-3p/miR-330-5p in an RNA-induced silencing complex (RISC) dependent manner. Dual-luciferase reporter assays demonstrated that pyruvate kinase M2 (PKM2) was one of the targets of miR-326-3p/miR-330-5p. As a rate-limiting enzyme in the aerobic glycolytic pathway, PKM2 accelerated gastric cancer cells' glucose uptake and increased cell viability. Taken together, circATP2B1 captured miR-326-3p/miR-330-5p and decreased the suppression of PKM2 by miR-326-3p/miR-330-5p, thus aiding the aerobic glycolysis and proliferation of gastric cancer cells. This study identified a novel molecular pathway in gastric cancer that may provide more targets for reversing cancer metabolic reprogramming, as well as a potential strategy for targeted therapy of gastric cancer.

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.

Circ_0000511 accelerates the proliferation, migration and invasion, and restrains the apoptosis of breast cancer cells through the miR‑326/TAZ axis

Circular RNA 0000511 (circ_0000511) has been observed to be dysregulated in breast cancer (BC). However, the functions of circ_0000511 in breast cancer remain unknown. The expression levels of circ_0000511, ribonuclease P RNA component H1, microRNA-326 (miR-326) and transcriptional co-activator with PDZ-binding motif (TAZ) were examined by reverse transcription-quantitative PCR. Colony formation and MTT assays were conducted to analyze the cellular proliferative ability. The apoptotic rate was assessed by flow cytometry. Western blot analysis was used to evaluate the expression levels of B cell leukemia/lymphoma 2 (Bcl-2), Bcl-2 associated X apoptosis regulator, cleaved caspase-3 and TAZ. Transwell assays were performed to evaluate the migration and invasion of BC cells. The target interaction between miR-326 and circ_0000511 or TAZ was confirmed by dual-luciferase reporter assay. Xenograft assay was used to identify the function of circ_0000511 in vivo. Circ_0000511 abundance was abnormally elevated in BC tissue samples and cell lines compared with in matched normal cases. Circ_0000511 interference suppressed the proliferation, migration and invasion, and induced apoptosis of BC cells. miR-326 was a direct target of circ_0000511, and circ_0000511 silencing-mediated effects in BC cells were largely reversed by the knockdown of miR-326. miR-326 directly bound to TAZ mRNA, and TAZ accumulation largely attenuated miR-326 overexpression-induced effects in BC cells. Circ_0000511 upregulated the expression levels of TAZ partly via targeting miR-326 in BC cells. Circ_0000511 silencing restrained tumor growth in vivo. Circ_0000511 accelerated the proliferation, migration and invasion, while inhibiting the apoptosis of BC cells through upregulating TAZ expression via sponging miR-326. The circ_0000511/miR-326/TAZ axis may be a novel therapeutic target for BC treatment.

Long noncoding RNA nuclear-enriched abundant transcript 1 regulates proliferation and apoptosis of neuroblastoma cells treated by cisplatin by targeting miR-326 through Janus kinase/signal transducer and activator of transcription 3 pathway

Neuroblastoma is a common malignancy and frequently affects children, leading to a low survival rate. Long noncoding RNAs (lncRNAs) are reported to be closely related to cancer progression. The purpose of this study was to explore a novel mechanism of lncRNA nuclear-enriched abundant transcript 1 (NEAT1) in neuroblastoma. NEAT1 was upregulated in neuroblastoma cell lines (IMR32 and SK-N-SH). Overexpression of NEAT1 increased proliferation inhibited by cisplatin and decreased apoptosis promoted by cisplatin. MicroRNA-326 (miR-326) was a target of NEAT1 and miR-326 reintroduction abolished the effects of NEAT1 overexpression on cell proliferation and apoptosis. Moreover, NEAT1 overexpression activated Janus kinase/signal transducer and activator of transcription 3 (JAK1/STAT3) signaling pathway through absorbing miR-326. Besides, NEAT1 overexpression promoted tumor growth in vivo through stimulating the expression of p-JAK1 and p-STAT3 but inhibiting miR-326 expression. NEAT1 accelerated proliferation and weakened apoptosis of neuroblastoma cells treated by cisplatin by targeting miR-326 through activating JAK1/STAT3 signaling pathway, suggesting that NEAT1 was a potential biomarker against neuroblastoma.

Hsa_circRNA_0000518 facilitates breast cancer development via regulation of the miR-326/FGFR1 axis

Background

Breast cancer (BC) is a heterogeneous malignant tumor that threatens the health of women worldwide. Hsa_circRNA_0000518 (circ_0000518) has been revealed to be upregulated in BC tissues. However, the role and mechanism of circ_0000518 in BC are indistinct.

Methods

Quantitative real‐time polymerase chain reaction (qRT‐PCR) was implemented to detect the levels of circ_0000518, microRNA (miR)‐326, and fibroblast growth factor receptor 1 (FGFR1) mRNA in BC tissues and cells. Cell counting kit‐8 (CCK‐8), colony formation, flow cytometry, and transwell assays were executed to estimate BC cell proliferation, cell cycle progression, apoptosis, migration, and invasion. The relationship between circ_0000518 or FGFR1 and miR‐326 was verified by dual‐luciferase reporter and/or RNA immunoprecipitation (RIP) assays. The role of circ_0000518 in vivo was confirmed by xenograft assay.

Results

Circ_0000518 and FGFR1 were upregulated while miR‐326 was downregulated in BC tissues and cells. Circ_0000518 silencing impeded tumor growth in vivo and induced cell cycle arrest, apoptosis, cured proliferation, colony formation, migration, and invasion of BC cells in vitro. Circ_0000518 regulated FGFR1 expression via competitively binding to miR‐326 in BC cells. MiR‐326 inhibitor reversed the inhibitory influence of circ_0000518 knockdown on the malignant behaviors of BC cells. FGFR1 overexpression abolished miR‐326 mimic‐mediated influence on the malignant behaviors of BC cells.

Conclusions

Circ_0000518 facilitated BC development via regulation of the miR‐326/FGFR1 axis, suggesting that circ_0000518 might be a promising target for BC treatment.

CircRNA circ_POLA2 promotes lung cancer cell stemness via regulating the miR-326/GNB1 axis

Circular RNAs (CircRNAs) are a group of noncoding RNAs that have essential function in the development and progression of various cancers. The expression pattern and function of circRNA in lung cancer is not fully understood. In the present study, we aimed to investigate the expression profiles and underlying mechanism of circRNA circ_POLA2 in lung cancer cell stemness. Circ_POLA2 was highly expressed in lung cancer tissues and predicted a poor prognosis in lung cancer patients. Knockdown of circ_POLA2 inhibited the stemness of lung cancer cells, which is evident by the decreased sphere-formation ability, ALDH1 activity, and stemness marker expression, but had no effects on cell viability. Mechanistically, circ_POLA2 functioned as a ceRNA by sponging miR-326. Furthermore, miR-326 negatively regulated G protein subunit beta 1 (GNB1) expression by targeting its 3'-UTR (untranslated region). Intriguingly, we found that GNB1 was overexpressed and associated with poor prognosis in lung cancer patients. Overexpression of GNB1 could antagonize the inhibitory effect of circ_POLA2 knockdown on lung cancer cell stemness. In conclusion, circ_POLA2 promotes lung cancer cell stemness and progression via regulating the miR-326/GNB1 axis, which might serve as a novel therapeutic target for lung cancer patients.

The inhibition of microRNA-326 by SP1/HDAC1 contributes to proliferation and metastasis of osteosarcoma through promoting SMO expression

Osteosarcoma (OS) is a malignant bone cancer lacking of effective treatment target when the metastasis occurred. This study investigated the implication of MicroRNA-326 in OS proliferation and metastasis to provide the clue for the treatment of metastatic OS. This study knocked down SP1 in MG63 and 143B cells and then performed Microarray assay to find the expression of miRNAs that were influenced by SP1. MTT, EdU, wound-healing and cell invasion assays were performed to evaluated cell proliferation and invasion. OS metastasis to lung was detected in a nude mice model. ChIP assay and DAPA were applied to determine the regulatory effect of SP1 and histone deacetylase 1 (HDAC) complex on miR-326 expression. Human OS tissues showed lowly expressed miR-326 but highly expressed Sp1 and HDAC. Sp1 recruited HDAC1 to miR-326 gene promoter, which caused the histone deacetylation and subsequent transcriptional inhibition of miR-326 gene. miR-326 deficiency induced the stimulation of SMO/Hedgehog pathway and promoted the proliferation and invasion of 143B and MG63 cells as well as the growth and metastasis in nude mice. SP1/HDAC1 caused the transcriptional inhibition of miR-326 gene by promoting histone deacetylation; miR-326 deficiency conversely stimulated SMO/Hedgehog pathway that was responsible for the proliferation and metastasis of OS.

NOB1: A Potential Biomarker or Target in Cancer

Human NIN1/RPN12 binding protein 1 homolog (NOB1), an RNA binding protein, is expressed ubiquitously in normal tissues such as the lung, liver, and spleen. Its core physiological function is to regulate protease activities and participate in maintaining RNA metabolism and stability. NOB1 is overexpressed in a variety of cancers, including pancreatic cancer, non-small cell lung cancer, ovarian cancer, prostate carcinoma, osteosarcoma, papillary thyroid carcinoma, colorectal cancer, and glioma. Although existing data indicate that NOB1 overexpression is associated with cancer growth, invasion, and poor prognosis, the molecular mechanisms behind these effects and its exact roles remain unclear. Several studies have confirmed that NOB1 is clinically relevant in different cancers, and further research at the molecular level will help evaluate the role of NOB1 in tumors. NOB1 has become an attractive target in anticancer therapy because it is overexpressed in many cancers and mediates different stages of tumor development. Elucidating the role of NOB1 in different signaling pathways as a potential cancer treatment will provide new ideas for existing cancer treatment methods. This review summarizes the research progress made into NOB1 in cancer in the past decade; this information provides valuable clues and theoretical guidance for future anticancer therapy by targeting NOB1.

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.

CircRNA circ_POLA2 Promotes Cervical Squamous Cell Carcinoma Progression via Regulating miR-326/GNB1

Circular RNAs (circRNAs) are a group of non-coding RNAs that have an essential function in the development and progression of various cancers. The expression pattern and function of circRNA in cervical squamous cell carcinoma (CESC) are not fully understood. In the present study, we aimed to investigate the expression profiles and regulation mechanism of circRNA circ_POLA2 in CESC. Circ_POLA2 was highly expressed in CESC tissues and positively correlated with poor prognosis in CESC patients. Knockdown of circ_POLA2 using shRNA inhibited cervical cancer cell proliferation, migration, and invasion both in vitro and in vivo. Mechanistically, circ_POLA2 could sponge endogenous microRNA-326 (miR-326) and inhibit its expression. Furthermore, miR-326 negatively regulated G protein subunit beta 1 (GNB1) by targeting its 3'-UTR. Intriguingly, we found that GNB1 was overexpressed and associated with poor prognosis in CESC patients. Overexpression of GNB1 could antagonize the inhibitory effect of miR-326 on cervical cancer cell proliferation, migration, and invasion. In addition, we demonstrated that circ_POLA2/miR-326/GNB1 axis regulated ERK signaling. In conclusion, circ_POLA2 promotes cervical squamous cell carcinoma development and progression via regulating the miR-326/GNB1 axis, which might serve as a novel therapeutic target for CESC patients.

A Novel Circular RNA hsa_circRPPH1_015 Exerts an Oncogenic Role in Breast Cancer by Impairing miRNA-326-Mediated ELK1 Inhibition

Background: Breast cancer (BC) represents a heterogeneous disease with distinct subtypes and high tumor metastatic potentials. Recent researchers identify the implication of circular RNAs (circRNAs) in the initiation of BC. Herein, we uncover a novel circRNA hsa_circRPPH1_015 as a tumor promoter in BC.

Methods: A total of 86 paired cancerous and non-cancerous tissues were surgically resected and collected from BC patients. Cell proliferation, colony formation, and cell invasion were examined by Edu staining, clone formation assays, propidium iodide (PI)-labeled flow cytometry, and Transwell invasion assays. PCNA, Ki67, MMP-2, MMP-9, Cyclin D1, and CDK4 expression was assayed using Western blot analysis. RNA pull-down, dual-luciferase reporter gene assay, and RNA binding protein immunoprecipitation (RIP) assay were performed to investigate the relationships among hsa_circRPPH1_015, microRNA-326 (miR-326), and ELK1. The tumor growth of human BC MCF-7 cells in vivo was evaluated in nude mice by subcutaneous xenografts of MCF-7 cells.

Results: hsa_circRPPH1_015 expression was upregulated in BC tissues. Knockdown of hsa_circRPPH1_015 restrained the aggressive behavior of MCF-7. hsa_circRPPH1_015 could bind to miRNA-326 that negatively regulates ELK1. Elevation of miRNA-326 expression resulted in inhibition of cell proliferation, colony formation, and cell invasion of MCF-7. Disturbance of miRNA-326 or overexpression of ELK1 restored the proliferation and aggressiveness in hsa_circRPPH1_015-depleted MCF-7 cells. Tumor growth of MCF-7 cells in vivo was reduced in nude mice lack of endogenous hsa_circRPPH1_015 expression.

Conclusion: Overall, the present study demonstrates that hsa_circRPPH1_015 was an oncogene and unfavorable prognostic factor in BC, providing an exquisite therapeutic target for BC.

LncRNA HOXD-AS1 promotes the metastasis of human hepatocellular carcinoma via modulating miR-326/SLC27A4

Background

Mounting evidences have indicated that long non-coding RNA (lncRNA) HOXD cluster antisense RNA 1 (HOXD-AS1) is dysregulated and participates into the progression of cancers. This study aims to investigate the biological roles and mechanisms of HOXD-AS1 in the metastasis of hepatocellular carcinoma (HCC).

Methods

The quantitative real-time PCR (qPCR) assay was used to assess the level of miR-326 and HOXD-AS1 in HCC tissues and cell lines. The growth of HCC cell was analyzed by using CCK-8 assay and colony formation assay. The migration and invasion of HCC cell were investigated by using wound healing and transwell invasion analysis. The expressions of SLC27A4, N-cadherin and E-cadherin were determined by western blotting. The growth of HCC cell in vivo was assessed by using xenograft model.

Results

Here, we elaborated that HOXD-AS1 was overexpressed in HCC tissues than that in the adjacent normal tissues and the level of HOXD-AS1 was related with the aggressive phenotypes of HCC. Functionally, downregulation of HOXD-AS1 repressed the proliferation, invasion abilities of HCC cell in vitro and the distant metastasis of HCC cell in vivo. Further investigations demonstrated that HOXD-AS1 directly bound with miR-326 and thereby regulated its endogenous target gene, solute carrier family 27 member 4 (SLC27A4).

Conclusions

All these findings indicated that HOXD-AS1-miR-326-SLC27A4 axis participated into the progression of HCC.

MiR-363 suppresses cell migration, invasion, and epithelial-mesenchymal transition of osteosarcoma by binding to NOB1

Background

Osteosarcoma (OS) is a primary malignant bone tumor with a high rate of metastasis and a short 5-year survival rate. MiR-363 was downregulated in a variety of tumors and played a role in suppressing tumors. However, the roles of miR-363 in osteosarcoma remain unknown; thus, the purpose of this study was to explore the functions of miR-363 in osteosarcoma.

Methods

CCK-8 and transwell assays were performed to evaluate the proliferation, migration, and invasion abilities of MG63 cells. The epithelial-mesenchymal transition (EMT) and apoptosis-associated proteins were measured by using Western blot assay. Luciferase reporter assay was utilized to verify whether miR-363 directly bound to the 3′-UTR of NOB1 mRNA.

Results

MiR-363 was downregulated while NOB1 was upregulated in osteosarcoma clinical tissue specimens and cell lines as compared with the adjacent normal tissue specimens and normal cell line. The miR-363 is reversely correlated with the expression of NOB1 in osteosarcoma tissues. Overexpression of miR-363 suppressed the ability of cell migration, invasion, and EMT, whereas low expression of miR-363 promoted this ability. In addition, miR-363 inhibited osteosarcoma proliferation both in vitro and in vivo and inhibited the apoptosis in MG63 cells. Interference of NOB1 could inhibit the migration, invasion, and EMT of osteosarcoma cell line MG63. NOB1 was verified to be a direct target of miR-363 and its expression was mediated by miR-363. Re-expression of NOB1 could partially reverse the inhibitory effect of miR-363 on cell migration and invasion. In addition, low expression of miR-363 or overexpression of NOB1 predicted poor prognosis of osteosarcoma patients.

Conclusion

MiR-363 inhibited osteosarcoma the proliferation, migration, invasion, and EMT and induced the apoptosis by directly targeting NOB1 in MG63 cells. The newly identified miR-363/NOB1 axis provides novel insights into the pathogenesis of osteosarcoma.

MicroRNA-129-5p represses the growth and aggressiveness of oral squamous cell carcinoma via suppressing HMGB1

Recent investigations have suggested that microRNA-129-5p (miR-129-5p) is commonly dysregulated in multiple types of malignancies. Nevertheless, the roles of miR-129-5p in human oral squamous cell carcinoma (OSCC) are not well explored. Herein, we demonstrated that miR-129-5p was down-expressed in OSCC cells and tissues. Moreover, miR-129-5p overexpression restrained the growth, migration ability, and invasiveness of OSCC cells. Notably, high-mobility group box 1 protein (HMGB1) was identified as a downstream target of miR-129-5p. Additional, knockdown of HMGB1 suppressed the growth and aggressive phenotypes of human OSCC cells. Importantly, re-expression of HMGB1 impaired the inhibitory impacts of miR-129-5p on the metastasis of OSCC cells. Altogether, these results implied that miR-129-5p restrained the aggressiveness of OSCC cells through modulating HMGB1.

Circular RNA hsa_circ_0000467 Promotes the Development of Gastric Cancer by Competitively Binding to MicroRNA miR-326-3p

Circular RNAs are a class of endogenous noncoding RNAs that play an important role in gene regulation. These RNAs are involved in the development and progression of various cancers, but their roles in gastric cancer have not yet been thoroughly elucidated. This study showed that hsa_circ_0000467 expression was higher in gastric cancer tissues than in corresponding adjacent tissues (P < 0.050) and that hsa_circ_0000467 expression levels were correlated with gastric cancer histological grade (P < 0.050). In addition, hsa_circ_0000467 was remarkably upregulated in gastric cancer cell lines (P < 0.001). Cell function experiments indicated that hsa_circ_0000467 downregulation decreased the proliferation and invasion ability of BGC-823 and SGC-7901 cells and the number of cells entering the G2/M phase. A direct binding interaction was detected between hsa_circ_0000467 and miR-326-3p by dual-luciferase reporter assays. In addition, the results showed that inhibition of miR-326-3p reversed the decreases in the proliferation and invasion of BGC-823 and SGC-7901 cells caused by hsa_circ_0000647 downregulation. Inhibition of miR-326-3p also decreased the number of cells entering the G2/M phase and the expression of cyclin D1. In conclusion, hsa_circ_0000467 plays a regulatory role in the development and progression of gastric cancer by regulating miR-326-3p, and this circRNA may be a potential diagnostic marker and therapeutic target of gastric cancer.

MiR-326 targets MDK to regulate the progression of cardiac hypertrophy through blocking JAK/STAT and MAPK signaling pathways

Cardiac hypertrophy is a heart reaction to the increase of cardiac load, with the characteristics of increased expression of cardiac hypertrophy markers, enhanced protein synthesis, and enlarged cell area. However, molecular mechanisms in cardiac hypertrophy are still poorly substantiated. It has been reported that miRNAs can modulate human diseases, among which miR-326 has been reported as a biological regulator in human cancers, but its role in cardiac hypertrophy is rarely explored. This study focused on the exploration of the potential of miR-326 in cardiac hypertrophy. Our data revealed the downregulation of miR-326 in the TAC-induced hypertrophic mice and the Ang II-induced hypertrophic H9c2 cells. Functionally, miR-326 attenuated the effect of Ang II on cardiac hypertrophy in vitro. In addition, miR-326 negatively regulated JAK/STAT and MAPK signaling pathways. Mechanistically, miR-326 targeted and inhibited MDK to induce JAK/STAT and MAPK pathways. Rescue assays certified that miR-326 attenuated cardiac hypertrophy through targeting MDK and inhibiting JAK/STAT and MAPK signaling pathways. In brief, our study unveiled that miR-326 targets MDK to regulate the progression of cardiac hypertrophy through blocking JAK/STAT and MAPK signaling pathways, indicating that targeting miR-326 as a potential approach for cardiac hypertrophy treatment.

Gold nano-particles (AuNPs) carrying miR-326 targets PDK1/AKT/c-myc axis in hepatocellular carcinoma

Abnormal expression of microRNAs (miRNAs) contributes to tumour growth and invasion. MiR-326 expression often down-regulates in several kinds of cancer and low expression of miR-326 is linked with poor prognosis in cancer patients. In the present study, we aimed to explore the modulatory mechanism of miR-326 in hepatocellular carcinoma (HCC). miR-326 expression was significantly decreased in HCC cell lines and tissues. miR-326 decreased HCC cell growth by affecting cell-cycle progression and by promoting apoptosis. In addition, miR-326 inhibited HCC cell invasion by decreasing the EMT phenotype. We found that miR-326 functioned as a tumour suppressor by repressing its down-stream target PDK1. C-myc contributed to miR-326 down-regulation through binding at its promoter and inhibited its expression. Based on these results, we conducted a therapeutic experiment by using gold nano-particles (AuNPs) carrying miR-326. Restoration of miR-326 reduced tumour growth in vivo. Our findings suggest that miR-326 may be a candidate prognostic biomarker and a target for new therapies in HCC patients.

Long non-coding RNA HOTAIR functions as a competitive endogenous RNA to regulate PRAF2 expression by sponging miR-326 in cutaneous squamous cell carcinoma

Background

LncRNAs may exert a regulatory effect in tumorigenesis. Although the expression of lncRNA HOTAIR has been confirmed to be notably elevated in the tissues of CSCC, its biological mechanism in CSCC is still unknown.

Methods

HOTAIR expression level in CSCC cell lines was monitored via qRT-PCR. Then CCK-8 assay, Transwell assay and EdU assay were adopted to detect cell migration and proliferation. Meanwhile, through bioinformatics analysis and luciferase reporter gene detection, a new target of HOTAIR was identified. Additionally, Western blotting and RIP analysis were adopted to discuss the possible mechanism.

Results

HOTAIR expression in CSCC cell lines exhibited an obvious elevation. Cell function analysis revealed that HOTAIR overexpression remarkably facilitated CSCC cell migration, proliferation and EMT process, which were impeded by down-regulation of HOTAIR. Furthermore, HOTAIR competitively bound to miR-326, so as to positively modulate miR-326 expression.

Conclusions

These results present that HOTAIR, as a ceRNA, regulates PRAF2 expression by competitive binding to miR-326 during CSCC.

Functional analyses of microRNA-326 in breast cancer development

MicroRNA-326 (miR-326) was reported to be dysregulated and involved in the progression of multiple cancers. However, the clinical significance, biological role and underlying mechanism of miR-326 in the carcinogenesis of breast cancer are still unclear. In the present study, we showed that miR-326 was down-regulated in human breast cancer tissues and cell lines. Our results also revealed that miR-326 overexpression significantly suppressed breast cancer cell proliferation, migration and invasion, and induced cell cycle arrest at G₁/G₀ phase. Furthermore, Sex determining region Y-box (SOX) protein 12 (SOX12), a known oncogene, was identified as a direct target of miR-326 by luciferase reporter assay. Moreover, miR-326 expression was inversely correlated with SOX12 mRNA expression levels in human breast cancer specimens. Overexpression of SOX12 partially rescued the inhibitory effect on cell proliferation, migration and invasion in breast cancer cells caused by miR-326 overexpression. These findings suggested that miR-326 might play a suppressive role in breast cancer, at least in part, by targeting SOX12, rendering miR-326 a promising therapeutic target for breast cancer.

Long noncoding RNA PCAT1, a novel serum-based biomarker, enhances cell growth by sponging miR-326 in oesophageal squamous cell carcinoma

Long noncoding RNAs (lncRNAs) play important roles in the development and progression of human cancers. The lncRNA prostate cancer-associated transcript 1 (PCAT1) has been reported to be involved in multiple human cancers, including oesophageal squamous cell carcinoma (ESCC). However, the detailed biological functions, underlying mechanisms and clinical relevance of PCAT1 in ESCC remain unclear. Here, we confirmed that PCAT1 was highly expressed in ESCC tissues and cell lines. Knockdown of PCAT1 inhibited the growth of ESCC cells, whereas overexpression of PCAT1 showed the opposite effect both in vitro and in vivo. Moreover, knockdown of PCAT1 arrested the cell cycle at G2/M phase, reduced the expression of cyclin B1 and CDC2, and caused cells to be more sensitive to paclitaxel. Furthermore, PCAT1 could bind to miR-326, a tumour suppressor in diverse human cancers. Rescue experiments revealed that enforced expression of miR-326 attenuated the promotive effect of PCAT1 on ESCC cell growth. In addition, we discovered that PCAT1 was present in ESCC cell-derived exosomes, was higher in the serum of ESCC patients than those of healthy volunteer donors, and promoted cell growth through exosomes. Thus, our data indicate that PCAT1 promotes ESCC cell proliferation by sponging miR-326 and may serve as a non-invasive biomarker for ESCC.

Diagnostic biomarker and therapeutic target applications of miR-326 in cancers: A systematic review

MicroRNAs (miRNAs) are endogenous mediators of RNA interference and have key roles in the modulation of gene expression under healthy, inflamed, stimulated, carcinogenic, or other cells, and tissues of a pathological state. Many studies have proved the association between miRNAs and cancer. The role of miR-326 as a tumor suppressor miRNA in much human cancer confirmed. We will explain the history and the role of miRNAs changes, especially miR-326 in cancers and other pathological conditions. Attuned with these facts, this review highlights recent preclinical and clinical research performed on miRNAs as novel promising diagnostic biomarkers of patients at early stages, prediction of prognosis, and monitoring of the patients in response to treatment. All related publications retrieved from the PubMed database, with keywords such as epigenetic, miRNA, microRNA, miR-326, cancer, diagnostic biomarker, and therapeutic target similar terms from 1899 to 2018 with limitations in the English language. Recently, researchers have focused on the impacts of miRNAs and their association in inflammatory, autoinflammatory, and cancerous conditions. Recent studies have suggested a major pathogenic role in cancers and autoinflammatory diseases. Investigations have explained the role of miRNAs in cancers, autoimmunity, and autoinflammatory diseases, and so on. The miRNA-326 expression has an important role in cancer conditions and other diseases.

MicroRNAs contribute to ATP-binding cassette transporter- and autophagy-mediated chemoresistance in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has an elevated mortality rate, largely because of high recurrence and metastasis. Additionally, the main obstacle during treatment of HCC is that patients usually develop resistance to chemotherapy. Cancer drug resistance involves many different mechanisms, including alterations in drug metabolism and processing, impairment of the apoptotic machine, activation of cell survival signaling, decreased drug sensitivity and autophagy, among others. Nowadays, miRNAs are emerging as master regulators of normal physiology- and tumor-related gene expression. In HCC, aberrant expression of many miRNAs leads to chemoresistance. Herein, we particularly analyzed miRNA impact on HCC resistance to drug therapy. Certain miRNAs target ABC (ATP-binding cassette) transporter genes. As most of these miRNAs are downregulated in HCC, transporter levels increase and intracellular drug accumulation decrease, turning cells less sensitive to death. Others miRNAs target autophagy-related gene expression, inhibiting autophagy and acting as tumor suppressors. Nevertheless, due to its downregulation in HCC, these miRNAs do not inhibit autophagy or tumor growth and, resistance is favored. Concluding, modulation of ABC transporter and/or autophagy-related gene expression or function by miRNAs could be determinant for HCC cell survival under chemotherapeutic drug treatment. Undoubtedly, more insights on the biological processes, signaling pathways and/or molecular mechanisms regulated by miRNAs are needed. Anyway, miRNA-based therapy together with conventional chemotherapeutic drugs has a great future in cancer therapy.

miR-203 Inhibits the Invasion and EMT of Gastric Cancer Cells by Directly Targeting Annexin A4

Many studies have shown that downregulated miR-203 level is in a variety of cancers including gastric cancer (GC). However, the precise molecule mechanisms of miR-203 in GC have not been well clarified. In the current study, we investigated the biological functions and molecular mechanisms of miR-203 in GC cell lines. We found that miR-203 is downregulated in GC tissues and cell lines. Moreover, the low level of miR-203 was associated with increased expression of annexin A4 in GC tissues and cell lines. The invasion and EMT of GC cells were suppressed by overexpression of miR-203. However, downregulation of miR-203 promoted invasion and EMT of GC cells. Bioinformatics analysis predicted that annexin A4 was a potential target gene of miR-203. Next, luciferase reporter assay confirmed that miR-203 could directly target annexin A4. Consistent with the effect of miR-203, downregulation of annexin A4 by siRNA inhibited the invasion and EMT of GC cells. Introduction of annexin A4 in GC cells partially blocked the effects of miR-203 mimic. Introduction of miR-203 directly targeted annexin A4 to inhibit the invasion and EMT of GC cells. Overall, reactivation of the miR-203/annexin A4 axis may represent a new strategy for overcoming metastasis of GC.

MiR-326/Sp1/KLF3: A novel regulatory axis in lung cancer progression

OBJECTIVES

To investigate the function and regulatory mechanism of Krüppel-like factor 3 (KLF3) in lung cancer.

MATERIALS AND METHODS

KLF3 expression was analysed by qRT-PCR and Western blot assays. The proliferation, migration, invasion, cycle and apoptosis were measured by CCK-8 and EdU, wound-healing and Transwell, and flow cytometry assays. The tumour growth was detected by nude mouse tumorigenesis assay. In addition, the interaction between KLF3 and Sp1 was accessed by luciferase reporter, EMSA and ChIP assay. JAK2, STAT3, PI3K and p-AKT levels were evaluated by Western blot and IHC assays.

RESULTS

The results indicated that KLF3 expression was elevated in lung cancer tissues. Knockdown of KLF3 inhibited lung cancer cell proliferation, migration and invasion, and induced cell cycle arrest and apoptosis. In addition, the downregulation of KLF3 suppressed tumour growth in vivo. KLF3 was transcriptionally activated by Sp1. miR-326 could bind to 3'UTR of Sp1 but not KLF3 and decreased the accumulation of Sp1, which further indirectly reduced KLF3 expression and inactivated JAK2/STAT3 and PI3K/AKT signaling pathways in vitro and in vivo.

CONCLUSIONS

Our data demonstrate that miR-326/Sp1/KLF3 regulatory axis is involved in the development of lung cancer, which hints the potential target for the further therapeutic strategy against lung cancer.

Involvement of H19/miR-326 axis in hepatocellular carcinoma development through modulating TWIST1

Overexpression of long noncoding RNA (lncRNA) H19 has been observed in various cancers, which indicates that H19 exert important roles in the progression of carcinogenesis. MiR-326 has been reported to play tumor suppressive roles in multiple tumors. Recently, the competing endogenous RNA (ceRNA) hypothesis has implied that lncRNAs might function as molecular sponges for microRNAs in various cancers. However, the roles of H19/miR-326 in human hepatocellular carcinoma (HCC) still remain unclear. The aim of our study was to determine H19/miR-326 expression in HCC cells and investigate their roles in HCC development. We found that H19 was significantly elevated and miR-326 was decreased in HCC cells including Hep3B, HepG2, MHCC-97L, SK-hep1, Hun7, SMCC-7721 compared with LO2 cells, respectively. In the subsequent experiments, we observed that inhibition of H19 can repress HCC cell growth, migration, and invasion in vitro. H19 downregulation can increase miR-326 expression in HCC cells. Meanwhile, miR-326 mimics can also inhibit HCC progression, whereas miR-326 inhibitors exhibited a reverse phenomenon by modulating H19 expression. In addition, a negative association between H19 and miR-326 was predicted and confirmed. Furthermore, the transcription factor TWIST1 has been recognized as a significant regulator in tumor progression. Here, by performing bioinformatics analysis, TWIST1 was identified as a downstream target of miR-326. The findings of our study implied that lncRNA H19 can serve as a ceRNA to sponge miR-326 and modulate TWIST1 levels in HCC pathogenesis. Taken these together, these findings indicated that H19/miR-326/TWIST1 axis was involved in HCC development and can indicate a novel HCC target.

Vascular endothelial growth factor C promotes cervical cancer cell invasiveness via regulation of microRNA-326/cortactin expression

Vascular endothelial growth factor C (VEGF-C) accelerates cervical cancer metastasis, while the detailed mechanism remains largely unknown. Recent evidence indicates that microRNA play a crucial role in controlling cancer cell invasiveness. In the present study, we investigated the role of miR-326 in VEGF-C-induced cervical cancer cell invasion. VEGF-C expression was higher and miR-326 was much lower in primary cervical cancer specimens than that in non-cancerous specimens, and a negative correlation between VEGF-C and miR-326 was found. On cervical carcinoma cell line SiHa cells, treatment with VEGF-C downregulated miR-326 level and increased cortactin protein expression. Transfection with miR-326 mimic reversed cortactin expression induced by VEGF-C, suggesting that VEGF-C increased cortactin via downregulation of miR-326. VEGF-C activated c-Src and c-Src inhibitor PP2 abolished VEGF-C effect on miR-326 and cortactin expression, implying that VEGF-C regulated miR-326/cortactin via c-Src signaling. VEGF-C promoted SiHa cell invasion index, which was largely inhibited by transfection with miR-326 antagonist or by siRNA against cortactin. In conclusion, our findings implied that VEGF-C reduced miR-326 expression and increased cortactin expression through c-Src signaling, leading to enhanced cervical cancer invasiveness. This may shed light on potential therapeutic strategies for cervical cancer therapy.

The MicroRNA-326: Autoimmune diseases, diagnostic biomarker, and therapeutic target

MicroRNAs (miRNAs) are uniquely regulated in healthy, inflamed, activated, cancerous, or other cells and tissues of a pathological state. Many studies confirm that immune dysregulation and autoimmune diseases with inflammation are correlated with various miRNA expression changes in targeted tissues and cells in innate or adaptive immunity. In this review, we will explain the history and classification of epigenetic changes. Next, we will describe the role of miRNAs changes, especially mir-326 in autoimmunity, autoinflammatory, and other pathological conditions. A systematic search of MEDLINE, Embase, and Cochrane Library was presented for all related studies from 1899 to 2017 with restrictions in the English language. In recent years, researchers have concentrated on mostly those roles of miRNA that are correlated with the inflammatory and anti-inflammatory process. Latest studies have proposed a fundamental pathogenic role in cancers and autoinflammatory diseases. Studies have described the role of microRNAs in autoimmunity and autoinflammatory diseases, cancers, and so on. The miRNA-326 expression plays a significant role in autoimmune and other types of diseases.

Molecular profile of urine extracellular vesicles from normo-functional kidneys reveal minimal differences between living and deceased donors

BACKGROUND

Kidney transplantation (KTx) is the best therapeutic approach for chronic kidney diseases leading to irreversible kidney failure. Considering the origin of the graft, several studies have reported differences between living (LD) and deceased donors (DD) in graft and patient survival. These differences seem to be related to multiple factors including, donor age and time of cold ischemia among others. Many of transplanted organs come from old-aged DDs, in which pre-transplant biopsy is recommended. However, kidney biopsy has several limitations, and there is a need to develop alternatives to assess the status of a kidney before transplantation. As the analysis of urinary extracellular vesicles (uEVs) rendered promising results as non-invasive biomarkers of kidney-related pathologies, this pilot study aimed to investigate whether profiling uEVs of LDs and DDs may be of help to assess the quality of the kidney before nephrectomy.

METHODS

uEVs from 5 living donors and 7 deceased donors were isolated by size-exclusion chromatography, and their protein and miRNA content were analysed by liquid chromatography followed by mass spectrometry and next generation sequencing, respectively. Then, hierarchical clustering and venn diagrams were done with Perseus software and InteractiVenn tool. Specific EVs data bases were also used for Gene Ontology analysis.

RESULTS

Next generation sequencing revealed that uEVs from DDs contained less miRNAs than LDs, but most of the DD-expressed miRNAs were shared with LDs (96%). Only miR-326 (targeting the apoptotic-related Bcl2) was found significantly over-represented in LD. Focusing on the protein content, we detected a low intra-group correlation in both types of donors. Despite these differences, hierarchical clustering of either miRNA or protein data could not identify a differential profile between LDs and DDs. Of note, 90% of transplanted patients had a functional graft after a year from KTx.

CONCLUSIONS

In this pilot study we found that, in normo-functional grafts, minor differences in uEVs profile could not discriminate between LDs and DDs.

Lnc-ISG20 Inhibits Influenza A Virus Replication by Enhancing ISG20 Expression

Long noncoding RNAs (lncRNAs) are involved in many aspects of cellular processes, including the antiviral immune response. To identify influenza A virus (IAV)-related lncRNAs, we performed RNA deep sequencing to compare the profiles of lncRNAs in A549 and HEK293T cells with or without IAV infection. We identified an IAV-upregulated lncRNA named lnc-ISG20 because it shares most of its sequence with ISG20. We found that lnc-ISG20 is an interferon-stimulated gene similar to ISG20. Overexpression of lnc-ISG20 inhibited IAV replication, while lnc-ISG20 knockdown favored viral replication, suggesting that lnc-ISG20 is inhibitory to IAV replication. Further study indicated that overexpression of lnc-ISG20 enhances ISG20 protein levels, while knockdown of lnc-ISG20 reduces ISG20 protein levels in A549 cells induced with poly(I·C) and Sendai virus. We demonstrated that lnc-ISG20 inhibits IAV replication in an ISG20-dependent manner. As lnc-ISG20 did not affect the mRNA level of ISG20, we postulated that lnc-ISG20 may function as endogenous RNA competing with ISG20 to enhance its translation. Indeed, we identified that microRNA 326 (miR-326) is a mutual microRNA for both ISG20 and lnc-ISG20 that targets the 3' untranslated region of ISG20 mRNA to inhibit its translation. We confirmed that lnc-ISG20 can bind miR-326, which in turn decreased the amount of miR-326 bound to ISG20 mRNA. In conclusion, we identified that the IAV-upregulated lnc-ISG20 is a novel interferon-stimulated gene that elicits its inhibitory effect on IAV replication by enhancing ISG20 expression. We demonstrated that lnc-ISG20 functions as a competitive endogenous RNA to bind miR-326 to reduce its inhibition of ISG20 translation. Our results revealed the mechanism by which lnc-ISG20 inhibits IAV replication.IMPORTANCE The replication of influenza A virus is regulated by host factors. However, the mechanisms by which lncRNAs regulate IAV infection are not well understood. We identified that lnc-ISG20 is upregulated during IAV infection and is also an interferon-stimulated gene. We demonstrated that lnc-ISG20 can enhance ISG20 expression, which in turn inhibits IAV replication. Our studies indicate that lnc-ISG20 functions as a competing endogenous RNA that binds miR-326 and reduces its inhibitory effect on ISG20. Taken together, our findings reveal the mechanistic details of lnc-ISG20 negatively regulating IAV replication. These findings indicate that lnc-ISG20 plays an important role during the host antiviral immune response.

MicroRNA-599 suppresses glioma progression by targeting RAB27B

MicroRNAs (miRNAs/miRs) serve tumor promoting or suppressive roles in different human cancer types, including glioma; however, the regulatory underlying mechanism by which miR-599 affects glioma progression remains largely unknown. The aim of the present study was to investigate the expression of miR-599 in glioma, as well as the underlying regulatory mechanism. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were used to examine mRNA and protein expression, respectively. MTT, wound healing and transwell assays were conducted to study cell proliferation, migration and invasion, respectively. A dual-luciferase reporter gene assay was used to confirm the targeting association between miR-599 and Ras-related protein Rab-27B (hereafter RAB27B). In the present study, miR-599 expression was observed to be significantly downregulated in human glioma tissues and cell lines, when compared with normal brain tissues and normal human astrocyte cells, respectively. Low miR-599 expression was significantly associated with glioma progression. Ectopic expression of miR-599 caused a significant reduction in the proliferation, migration and invasion of U-87MG Uppsala and U251 cells. Bioinformatics analysis and dual-luciferase reporter gene assay data identified that RAB27B was a direct target gene of miR-599. The mRNA and protein expression of RAB27B was significantly downregulated following miR-599 overexpression in U-87MG Uppsala and U251 cells. Rescue experiments demonstrated that RAB27B rescued the miR-599-induced inhibition of glioma cell growth, migration and invasion. In addition, RAB27B expression was significantly upregulated in glioma tissues and cell lines, and the expression levels of RAB27B were inversely correlated with miR-599 levels in glioma tissues; therefore, the present study demonstrated that miR-599 exerts a tumor-suppressive role in glioma progression by targeting RAB27B, indicating that miR-599 may be used as a potential candidate for glioma treatment.

MicroRNA-153 functions as a tumor suppressor in gastric cancer via targeting Kruppel-like factor 5

Various microRNAs (miRs) have been demonstrated to serve important roles in gastric cancer (GC). miR-153 in particular has been reported to serve a suppressive role in GC; however, the underlying mechanism remains unclear. In the present study Reverse transcription-quantitative polymerase chain reaction and western blot analysis were used to examine the mRNA and protein expression of Kruppel-like factor 5. An MTT, wound healing and transwell assay were used to study cell proliferation, migration and invasion, respectively. In the present study, quantitative polymerase chain reaction data indicated that miR-153 was significantly downregulated in GC tissues compared with the adjacent non-tumor tissues. In addition, the reduced expression of miR-153 was significantly associated with GC aggressiveness and poor prognosis of patients. The expression of miR-153 was also reduced in GC cell lines, including KATO III, NCI-N87, SNU-16 and SNU-5, when compared with normal gastric epithelial GES-1 cells. Overexpression of miR-153 in the GC SNU-5 cells by miR-153 mimic transfection significantly inhibited the cell proliferation, migration and invasion. Furthermore, KLF5 was identified as a target gene of miR-153 in SNU-5 cells by bioinformatics prediction. It was observed that KLF5 was significantly upregulated in GC tissues and cell lines, and its expression was negatively regulated by miR-153 in SNU-5 cells. Overexpression of KLF5 impaired the suppressive effects of miR-153 on the proliferation, migration and invasion of SNU-5 cells. In conclusion, the present study demonstrated that miR-153 serves a tumor suppressive role in GC, at least partly, through directly targeting KLF5, thus highlighting the clinical significance of miR-153 in GC.

MicroRNA-302 inhibits cell migration and invasion in cervical cancer by targeting DCUN1D1

MicroRNA serve crucial roles in a variety of human cancer types. The miR-302-367 cluster has been reported to suppress the proliferation of cervical carcinoma cells through the novel target AKT1; however, the molecular mechanism of miR-302 in cervical cancer metastasis remains unclear. The present study aimed to investigate the clinical significance of miR-302-3p expression in cervical cancer, and to examine the regulatory mechanism of miR-302-3p in the malignant phenotypes of cervical cancer cells. The present data indicated that miR-302-3p was significantly downregulated in cervical cancer tissues compared with the level in adjacent non-tumor tissues, and low expression of miR-302-3p was significantly associated with node metastasis, advanced clinical stage, and poor prognosis in patients with cervical cancer. Restoration of miR-302-3p expression caused a significant reduction in cervical cancer cell migration and invasion. Defective in cullin neddylation 1 domain containing 1 (DCUN1D1) was identified as a novel target gene of miR-302-3p, and miR-302-3p negatively regulated the mRNA and protein expression of DCUN1D1 in cervical cancer HeLa cells. Additionally, overexpression of DCUN1D1 rescued the effects of miR-302-3p on the migration and invasion of cervical cancer cells. Furthermore, DCUN1D1 was upregulated in cervical cancer tissues compared with the levels in adjacent tissues, and its high expression was associated with node metastasis, advanced clinical stage, and shorter survival time in patients with cervical cancer. Notably, a negative correlation between miR-302-3p and DCUN1D1 expression in cervical cancer tissues was observed. Taken together, the present study suggests that miR-302-3p serves a suppressive role in cervical cancer metastasis, partly at least, via directly targeting DCUN1D1. Therefore, miR-302-3p/DCUN1D1 may be a potential therapeutic target for cervical cancer treatment.