Sevoflurane Suppresses Glioma Cell Proliferation, Migration, and Invasion Both In Vitro and In Vivo Partially Via Regulating KCNQ1OT1/miR-146b-5p/STC1 Axis

Background: Sevoflurane (Sev), a volatile anesthetic agent, is widely used in neurosurgery for anesthesia maintenance, accompanied with antitumor activity postanesthesia in multiple human cancers, including glioma. However, the molecular mechanism of Sev in glioma is largely unclear, including associated informative noncoding RNAs, such as long noncoding RNAs (lncRNA) and microRNAs (miRNAs). Methods: Expression of lncRNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1), miRNA (miR)-146b-5p, and stanniocalcin-1 (STC1) was measured by real-time quantitative polymerase chain reaction and Western blotting. Cell proliferation, apoptosis, migration, and invasion in vitro were examined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay, fluorescence-activated cell sorting method, and transwell assays, respectively. Tumor growth in vivo was determined by xenograft models. The direct interaction between genes was confirmed by dual-luciferase reporter assay. Results: Sev enhanced apoptotic rate, but inhibited cell viability, migration, and invasion abilities of human glioma A172 and U251 cells in vitro, as well as tumor growth inhibition in vivo. The tumor-suppressive role of Sev in glioma was accompanied with downregulated KCNQ1OT1 and STC1, and upregulated miR-146b-5p. Overexpression of KCNQ1OT1 through transfection reversed, while KCNQ1OT1 silencing aggravated the antitumor role of Sev in A172 and U251 cells. Moreover, KCNQ1OT1-mediated tumor-promoting activity in A172 and U251 cells under Sev treatment was abrogated by miR-146b-5p restoration or STC1 deletion. Essentially, KCNQ1OT1 could positively regulate STC1 by acting as miR-146b-5p decoy. Conclusion: KCNQ1OT1 knockdown mediated the role of Sev in glioma cell proliferation, apoptosis, migration, and invasion both in vitro and in vivo through miR-146b-5p/STC1 pathway.

MiR-146b-5p enriched bioinspired exosomes derived from fucoidan-directed induction mesenchymal stem cells protect chondrocytes in osteoarthritis by targeting TRAF6

Osteoarthritis (OA) is a common degenerative joint disease characterized by progressive cartilage degradation and inflammation. In recent years, mesenchymal stem cells (MSCs) derived exosomes (MSCs-Exo) have attracted widespread attention for their potential role in modulating OA pathology. However, the unpredictable therapeutic effects of exosomes have been a significant barrier to their extensive clinical application. In this study, we investigated whether fucoidan-pretreated MSC-derived exosomes (F-MSCs-Exo) could better protect chondrocytes in osteoarthritic joints and elucidate its underlying mechanisms. In order to evaluate the role of F-MSCs-Exo in osteoarthritis, both in vitro and in vivo studies were conducted. MiRNA sequencing was employed to analyze MSCs-Exo and F-MSCs-Exo, enabling the identification of differentially expressed genes and the exploration of the underlying mechanisms behind the protective effects of F-MSCs-Exo in osteoarthritis. Compared to MSCs-Exo, F-MSCs-Exo demonstrated superior effectiveness in inhibiting inflammatory responses and extracellular matrix degradation in rat chondrocytes. Moreover, F-MSCs-Exo exhibited enhanced activation of autophagy in chondrocytes. MiRNA sequencing of both MSCs-Exo and F-MSCs-Exo revealed that miR-146b-5p emerged as a promising candidate mediator for the chondroprotective function of F-MSCs-Exo, with TRAF6 identified as its downstream target. In conclusion, our research results demonstrate that miR-146b-5p encapsulated in F-MSCs-Exo effectively inhibits TRAF6 activation, thereby suppressing inflammatory responses and extracellular matrix degradation, while promoting chondrocyte autophagy for the protection of osteoarthritic cartilage cells. Consequently, the development of a therapeutic approach combining fucoidan with MSC-derived exosomes provides a promising strategy for the clinical treatment of osteoarthritis.

miR-146b-5p downregulates IRAK1 and ADAM19 to suppress trophoblast proliferation, invasion, and migration in miscarriage†

A large proportion of miscarriages are classified as unexplained miscarriages since no cause is identified. No reliable biomarkers or treatments are available for these pregnancy losses. While our transcriptomic sequencing has revealed substantial upregulation of miR-146b-5p in unexplained miscarriage villous tissues, its role and associated molecular processes have yet to be fully characterized. Our work revealed that relative to samples from normal pregnancy, miR-146b-5p was significantly elevated in villous tissues from unexplained miscarriage patients and displayed promising diagnostic potential. Moreover, miR-146b-5p agomir contributed to higher rates of embryonic resorption in ICR mice. When overexpressed in HTR-8/SVneo cells, miR-146b-5p attenuated the proliferative, invasive, and migratory activity of these cells while suppressing the expression of MMP9 and immune inflammation-associated cytokines, including IL1B, IL11, CXCL1, CXCL8, and CXCL12. Conversely, inhibition of its expression enhanced proliferation, migration, and invasion abilities. Mechanistically, IL-1 receptor-associated kinase-1 and a disintegrin and metalloproteinase 19 were identified as miR-146b-5p targets regulating trophoblast function, and silencing IL-1 receptor-associated kinase-1 had similar effects as miR-146b-5p overexpression, while IL-1 receptor-associated kinase-1 overexpression could partially reverse the inhibitory impact of this microRNA on trophoblasts. miR-146b-5p may inhibit trophoblast proliferation, migration, invasion, and implantation-associated inflammation by downregulating IL-1 receptor-associated kinase-1 and a disintegrin and metalloproteinase 19, participating in the pathogenesis of miscarriage and providing a critical biomarker and a promising therapeutic target for unexplained miscarriage.

SEMA3G, downregulated by ncRNAs, correlates with favorable prognosis and tumor immune infiltration in kidney renal clear cell carcinoma

Kidney renal clear cell carcinoma (KIRC), relatively aggressive subtype of renal cell carcinoma, lacks of effective targets and promising biomarkers. Recently, although the function and immune correlation of semaphorin 3G (SEMA3G) in cancer draw more and more attention, its specific role and mechanism in KIRC are still not fully understood. In this work, we firstly conducted pan-cancer expression and survival bioinformatic analysis for SEMA3G and showed that SMEA3G might be a potential tumor suppressor and favorable prognostic biomarker in KIRC. Next, upstream noncoding RNA (ncRNA) regulatory mechanism of SEMA3G in KIRC was explored. By performing a series of in silico analyses, we identified that TBX2-AS1-miR-146a/b-5p axis was partially responsible for SEMA3G downregulation in KIRC. Furthermore, we also confirmed significant correlation of SEMA3G expression with tumor immune infiltration levels, expression of biomarkers of immune cells or immune checkpoints in KIRC. Taken together, the current data elucidated that ncRNA-caused downregulation of SEMA3G markedly linked to favorable prognosis and tumor immune infiltration in KIRC.

miR-146b-5p promotes duck Tembusu virus replication by targeting RPS14

Duck Tembusu virus (DTMUV), belonging to the Flaviviridae family, is a major virus that affects duck health in China. MicroRNAs (miRNAs) play an important role in viral replication. However, little is known about the function of miRNAs during DTMUV infection. Here, the host miR-146b-5p was found to regulate DTMUV replication. When DTMUV infected duck embryo fibroblasts (DEFs), the expression levels of miR-146b-5p increased significantly over time. Moreover, the viral RNA copies, E protein expression levels and virus titers were all upregulated when miR-146b-5p was overexpressed in DEFs. The opposite results were also observed upon knockdown of miR-146b-5p in DEFs. To explore the mechanism by which miR-146b-5p promoted DTMUV replication, mass spectrometry, and RNA pull-down assays were employed. Ribosomal protein S14 (RPS14), a component of 40S ribosomal proteins, was identified to interact with miR-146b-5p. In addition, the relative mRNA expression levels of RPS14 gene were negatively modulated by miR-146b-5p. Subsequently, it was found that overexpression of RPS14 could decrease the replication of DTMUV, and the reverse results were also detected by knockdown of RPS14. In conclusion, this study revealed that miR-146b-5p promoted DTMUV replication by targeting RPS14, which provides a new mechanism by which DTMUV evades host defenses and a new direction for further antiviral strategies development.

Modulation of miR-146b Expression during Aging and the Impact of Physical Activity on Its Expression and Chondrogenic Progenitors

The finding of molecules associated with aging is important for the prevention of chronic degenerative diseases and for longevity strategies. MicroRNAs (miRNAs) are post-transcriptional regulators involved in many biological processes and miR-146b-5p has been shown to be involved in different degenerative diseases. However, miR-146b-5p modulation has not been evaluated in mesenchymal stem cells (MSCs) commitment or during aging. Therefore, the modulation of miR-146b-5p in the commitment and differentiation of mesenchymal cells as well as during maturation and aging in zebrafish model were analyzed. In addition, circulating miR-146b-5p was evaluated in human subjects at different age ranges. Thus, the role of physical activity in the modulation of miR-146b-5p was also investigated. To achieve these aims, RT (real-time)-PCR, Western blot, cell transfections, and three-dimensional (3D) culture techniques were applied. Our findings show that miR-146b-5p expression drives MSCs to adipogenic differentiation and increases during zebrafish maturation and aging. In addition, miR-146b-5p expression is higher in females compared to males and it is associated with the aging in humans. Interestingly, we also observed that the physical activity of walking downregulates circulating miR-146b-5p levels in human females and increases the number of chondroprogenitors. In conclusion, miR-146b-5p can be considered an age-related marker and can represent a useful marker for identifying strategies, such as physical activity, aimed at counteracting the degenerative processes of aging.

Targeting miR-146b-5p to Regulate KDM6B Expression Aggravates Bronchopulmonary Dysplasia

miR-146b-5p has been studied to be highly expressed in bronchopulmonary dysplasia (BPD), but whether it is involved in regulating the process of BPD in premature infants remains unclear. This study was to explore miR-146b-5p in premature BPD and reveal its molecular mechanism. BPD mouse model and high-oxygen MLE-12 cell model were established. HE staining, TUNEL staining, and IF staining were conducted to evaluate the pathological injury and protein expression in mouse lung tissue. LDH assay, MMT assay, and flow cytometry were achieved to evaluate cytotoxicity, cell viability, and apoptosis. ELISA and immunoblotting were performed to evaluate inflammatory cytokines and Wnt pathway proteins in lung tissues and cells. Dual-luciferase reporter assay and RIP assay were needed to examine the targeting relationship between miR-146b-5p and KDM6B. miR-146b-5p was abundantly expressed in BPD and KDM6B was lowly expressed. miR-146b-5p knockdown improved hyperoxia-induced lung epithelial cell inflammation and apoptosis in both models. miR-146b-6p upregulation or KDM6B downregulation aggravated hyperoxia-induced inflammation and apoptosis of lung epithelial cells. This effect of overexpressing miR-146b-5p was rescued by forcing KDM6B. MiR-146b-5p activated Wnt signaling by regulating KDM6B. miR-146b-5p activates the Wnt pathway through targeted regulation of KDM6B, thereby aggravating hyperoxia-induced inflammation and apoptosis of lung epithelial cells.

MiR-146b-5p regulates the scavenging effect of GPx-3 on peroxide in papillary thyroid cancer cells

Background

Glutathione peroxidase (GPx) is an important antioxidant enzyme in thyroid follicular cells. Reduced levels of glutathione peroxidase 3 (GPx-3) expression in papillary thyroid cancer (PTC) are associated with poor prognosis. However, the reason for the decreased expression level of GPx-3 in PTC is unclear.

Methods

The expression of GPx-3 in papillary thyroid carcinoma and adjacent normal tissue (n = 18) was detected by Western blotting. Bioinformatics was used to predict the relationship between the level of GPx-3 and gender, age, lymph node metastasis, stage, BRAFV600E mutation, and recurrence-free survival of patients. The possible upstream microRNAs of GPx-3 were analyzed by bioinformatics tools also. We verified the relationship between GPx-3 and upstream microRNA by dual luciferase reporter assay and enzyme-linked immunosorbent assay (ELISA).

Results

The protein level of GPx-3 decreased in PTC, and analysis of public database datasets suggests that its decreased expression may be associated with the BRAFV600E mutation. MiR-146b-5p was significantly overexpressed in PTC. The dual luciferase reporter assay verified the effect of miR-146b-5p on 3'-UTR of GPx-3 mRNA. Knockdown of miR-146b-5p in thyroid cancer cell lines TPC-1 and BCPAP increased GPx-3 expression levels, accompanied by an increase in the conversion of glutathione (GSH) to oxidized glutathione (GSSG).

Conclusions

In conclusion, the level of GPx-3 decreases in papillary thyroid carcinoma and impairs intracellular peroxide clearance, due to the inhibitory effect of miR-146b-5p. The accumulation of intracellular peroxides may contribute to the poor prognosis of thyroid cancer.

MiR-146b-5p/SEMA3G regulates epithelial-mesenchymal transition in clear cell renal cell carcinoma

OBJECTIVE

The primary purpose was to unveil how the miR-146b-5p/SEMA3G axis works in clear cell renal cell carcinoma (ccRCC).

METHODS

ccRCC dataset was acquired from TCGA database, and target miRNA to be studied was further analyzed using survival analysis. We performed miRNA target gene prediction through the database, and those predicted miRNAs were intersected with differential mRNAs. After calculating the correlation between miRNAs and mRNAs, we completed the GSEA pathway enrichment analysis on mRNAs. MiRNA and mRNA expression was examined by qRT-PCR. Western blot was introduced to detect SEMA3G, MMP2, MMP9 expression, epithelial-mesenchymal transition (EMT) marker proteins, and Notch/TGF-β signaling pathway-related proteins. Targeted relationship between miRNA and mRNA was validated using a dual-luciferase test. Transwell assay was employed to assess cell migration and invasion. Wound healing assay was adopted for evaluation of migration ability. The effect of different treatments on cell morphology was observed by a microscope.

RESULTS

In ccRCC cells, miR-146b-5p was remarkably overexpressed, yet SEMA3G was markedly less expressed. MiR-146b-5p was capable of stimulating ccRCC cell invasion, migration and EMT, and promoting the transformation of ccRCC cell morphology to mesenchymal state. SEMA3G was targeted and inhibited via miR-146b-5p. MiR-146b-5p facilitated ccRCC cell migration, invasion, morphology transforming to mesenchymal state and EMT process by targeting SEMA3G and regulating Notch and TGF-β signaling pathways.

CONCLUSION

MiR-146b-5p regulated Notch and TGF-β signaling pathway by suppressing SEMA3G expression, thus promoting the growth of ccRCC cells, which provides a possible target for ccRCC therapy and prognosis prediction.

Exosomal miR-146b-5p derived from cancer-associated fibroblasts promotes progression of oral squamous cell carcinoma by downregulating HIPK3

OBJECTIVES

Cancer-associated fibroblasts (CAFs) are vital constituents of the tumor microenvironment (TME) and play a predominant role in oral squamous cell carcinoma (OSCC) progression. We aimed to investigate the effect and mechanism of exosomal miR-146b-5p derived from CAFs on the malignant biological behavior of OSCC.

MATERIALS AND METHODS

Illumina small RNA (sRNA) sequencing was conducted to determine the differential expression patterns of microRNAs (miRNAs) in exosomes derived from CAFs and normal fibroblasts (NFs). Transwell and cell counting kit-8 (CCK-8) assays and xenograft tumor models in nude mice were used to investigate the effect of CAF exosomes and miR-146b-p on the malignant biological behavior of OSCC. Reverse transcription quantitative real-time PCR (qRT-PCR), luciferase reporter, western blotting (WB) and immunohistochemistry assays were employed to investigate the underlying mechanisms involved in CAF exosomes that promote OSCC progression.

RESULTS

We demonstrated that CAF-derived exosomes were taken up by OSCC cells and enhanced the proliferation, migration, and invasion ability of OSCC. Compared with NFs, the expression of miR-146b-5p was increased in exosomes and their parent CAFs. Further studies showed that the decreased expression of miR-146b-5p inhibited the proliferation, migration and invasion ability of OSCC cells in vitro and the growth of OSCC cells in vivo. Mechanistically, miR-146b-5p overexpression led to the suppression of HIKP3 by directly targeting the 3'-UTR of HIPK3, as confirmed by luciferase assay. Reciprocally, HIPK3 knockdown partially reversed the inhibitory effect of the miR-146b-5p inhibitor on the proliferation, migration, and invasion ability of OSCC cells and restored their malignant phenotype.

CONCLUSIONS

Our results revealed that CAF-derived exosomes contained higher levels of miR-146b-5p than NFs, and miR-146b-5p overexpression in exosomes promoted the malignant phenotype of OSCC by targeting HIPK3. Therefore, inhibiting exosomal miR-146b-5p secretion may be a promising therapeutic modality for OSCC.

LINC01176 Hinders Thyroid Cancer Progression by Sponging miR-146b-5p to Enhance SGIP1

BACKGROUND

Long non-coding RNA (lncRNAs) plays a crucial role in tumor pathogenesis. However, the function of most of these genes remains unclear.

AIMS

In the present study, we aimed to unveil LINC01176's role in thyroid cancer.

METHODS

Western blotting and qRT-PCR were applied for the analysis of the expressions of LINC01176, miR-146b-5p, and SH3GL interacting endocytic adaptor 1 (SGIP1). Proliferative and migratory capabilities were assessed using the CCK-8 assay and wound-healing experiments, respectively. Apoptosis of the cells was studied by quantifying the apoptosis-related markers Bcl-2 and Bax by western blotting. Animal models were established using nude mice to determine the role of LINC01176 in tumorigenesis. MiR-146b-5p's putative binding to LINC01176 and SGIP1 was validated using dual-luciferase reporter and RIP analyses.

RESULTS

LINC01176 expression was downregulated in the thyroid cancer cell lines and tissues. LINC01176 overexpression represses cancer cell proliferation and migration but induces apoptosis. Elevated LINC01176 expression hampers tumorigenesis in animal models. LINC01176 targeted miR-146b-5p and negatively regulated its expression. Enrichment of miR-146b-5p counteracted the functional effects of LINC01176 overexpression. Additionally, miR-146b-5p interacted with SGIP1 and negatively regulated its expression. Thus, miR-146b-5p attenuates the anti-cancer effects of SGIP1.

CONCLUSION

LINC01176 negatively regulates the expression miR-146b-5p and upregulates SGIP1 expression. Hence, LINC01176 blocks the malignant progression of thyroid cancer.

LINC01311 exerts an inhibitory effect in thyroid cancer progression by targeting the miR-146b-5p/IMPA2 axis

BACKGROUND

A growing body of research suggests that long non-coding RNA (lncRNA) play an important role during the tumorigenesis and progression of cancers, including thyroid cancer (TC). Herein, we intended to uncover the role and mechanisms of LINC01311 in TC.

METHODS

The relative LINC01311, miR-146b-5p, and IMPA2 expressions were quantified by subjecting TC cells and tissues to western blotting and RT-qPCR. CCK-8 and scratch-wound healing assays were carried out for the evaluation of the proliferation and migration of TC cells. The apoptosis was evaluated by flow cytometry assay and western blotting of Bax and Bcl-2 proteins. Xenograft tumor model was also used to study how LINC01311 functions during TC cell growth. Luciferase reporter and RNA immunoprecipitation (RIP) assays were performed to ascertain miR-146b-5p's interactions with LINC01311 and IMPA2 3'UTR.

RESULTS

The TC cells and tissues exhibited a downregulation of LINC01311 and IMPA2 and an upregulation of miR-146b-5p. LINC01311 overexpression retarded TC cell growth in vitro as well as in vivo. The luciferase reporter and RIP assays verified that miR-146b-5p recognizes LINC01311 and IMPA2 3'UTR by base pairing. LINC01311 overexpression could counteract the oncogenic effect of miR-146b-5p in vitro. Moreover, IMPA2 upregulation could offset the tumor-promoting effect of miR-146b-5p.

CONCLUSION

LINC01311-mediated inhibition of TC cell growth was achieved by targeting the miR-146b-5p/IMPA2 axis. These findings support that targeting the LINC01311/miR-146b-5p/IMPA2 axis may be a promising approach against TC progression.

Sevoflurane inhibits the malignant phenotypes of glioma through regulating miR-146b-5p/NFIB axis

PURPOSE

Sevoflurane is a common used inhaled anesthetic that was reported to regulate the progression of multiple cancers. Here, we aimed to investigate the function and regulatory mechanism underlying sevoflurane in glioma cells.

METHODS

A172 and U251 cells were treated with different concentrations of sevoflurane. Colony formation, EdU satining and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), flow cytometry, and transwell assays were performed to evaluate cell proliferation, apoptosis, migration and invasion, respectively. Circ_VCAN, microRNA-146b-5p (miR-146b-5p) and nuclear factor I B (NFIB) expression levels were assessed by real-time quantitative PCR (RT-qPCR) or western blot. Bioinformatics analysis and dual-luciferase reporter assay were applied to evaluate the correlation between miR-146b-5p and circ_VCAN or NFIB. A xenograft glioma mice model was established to verify the effect of sevoflurane on tumor growth in vivo.

RESULTS

Sevoflurane (Sev) inhibited proliferation, migration, invasion, and elevated apoptosis of A172 and U251 cells. Sevoflurane treatment inhibited the expression of circ_VCAN and NFIB, but elevated the expression of miR-146b-5p in glioma cells. Overexpression of circ_VCAN alleviated the inhibition effects of sevoflurane on the malignant phenotypes of glioma in vitro and in vivo. Besides, miR-146b-5p is a target of circ_VCAN and negatively regulated NFIB expression. Overexpression of miR-146b-5p partly reversed the effects of circ_VCAN in Sev-treated glioma cells. Furthermore, miR-146b-5p deletion enhanced glioma progression in sevoflurane treated glioma cells by targeting NFIB. Moreover, circ_VCAN could upregulate NFIB expression by sponging miR-146b-5p in Sev-treated glioma cells.

CONCLUSION

Sevoflurane alleviated proliferation, migration and invasion, but enhanced apoptosis of glioma cells through regulating circ_VCAN/miR-146b-5p/NFIB axis.

Circ_0014235 confers Gefitinib resistance and malignant behaviors in non-small cell lung cancer resistant to Gefitinib by governing the miR-146b-5p/YAP/PD-L1 pathway

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as Gefitinib, have been recommended as the first-line treatment reagent for advanced EGFR-mutant non-small cell lung cancer (NSCLC). However, the mechanisms of drug resistance development are not fully determined. This study aimed to explore the role of circular RNA (circ_0014235) in Gefitinib-resistant NSCLC. The expression of circ_0014235, microRNA-146b-5p (miR-146b-5p) and Yes1 associated transcriptional regulator (YAP) mRNA was detected by quantitative real-time PCR (qPCR). Cell viability was detected by CCK-8 assay. Cell proliferation was assessed by colony formation assay and EdU assay. Cell cycle and cell apoptosis were determined by flow cytometry assay. The expression of marker proteins, YAP protein and programmed death ligand 1 (PD-L1) protein was detected by Western blot. The putative relationship between miR-146b-5p and circ_0014235 or YAP was ensured by dual-luciferase reporter assay and RIP assay. Animal models were established to explore the role of circ_0014235 in vivo. Circ_0014235 was highly expressed in Gefitinib-resistant NSCLC cells. Circ_0014235 downregulation reduced Gefitinib IC50, inhibited cell proliferation and induced cell apoptosis and cell cycle arrest in Gefitinib-resistant NSCLC cells, while these effects were reversed by the inhibition of miR-146b-5p, a target of circ_0014235. In addition, YAP was a target gene of miR-146b-5p, and circ_0014235 relieved miR-146b-5p-mediated inhibition on YAP by targeting miR-146b-5p. MiR-146b-5p restoration-blocked Gefitinib IC50 and cell malignant behaviors were recovered by YAP overexpression. YAP positively regulated PD-L1 expression, and YAP overexpression contributes to Gefitinib IC50 and cell malignant behaviors by upregulating PD-L1. Circ_0014235 confers Gefitinib resistance and malignant behaviors in Gefitinib-resistant NSCLC by governing the miR-146b-5p/YAP/PD-L1 pathway.

HIF1A-AS2 induces osimertinib resistance in lung adenocarcinoma patients by regulating the miR-146b-5p/IL-6/STAT3 axis

Although epidermal growth factor receptor tyrosine kinase inhibitors (TKIs) show efficacy in lung adenocarcinoma (LUAD) patients, TKI resistance inevitably develops, limiting long-term results. Thus, there is an urgent need to address drug resistance in LUAD. Long non-coding RNA (lncRNA) HIF1A-AS2 could be a critical mediator in the progression of various tumor types. We examined the function of HIF1A-AS2 in modifying tumor aggravation and osimertinib resistance in lung adenocarcinoma. Using clinical samples, we showed that HIF1A-AS2 was upregulated in LUAD specimens, predicting poorer overall survival and disease-free survival. HIF1A-AS2 silencing inhibited the proliferation, migration, and tumorigenesis of LUAD cells and therapeutic efficacy of osimertinib against tumor cells in vitro and in vivo. RNA precipitation assays, western blotting, luciferase assays, and rescue experiments demonstrated that HIF1A-AS2 sponged microRNA-146b-5p (miR-146b-5p), promoting interleukin-6 (IL-6) expression, activating the IL-6/STAT3 pathway, and leading to LUAD progression. miR-146b-5p and IL-6 levels were correlated with the prognosis of LUAD patients. Our results indicated that HIF1A-AS2 functions as an oncogenic factor in adenocarcinoma cells by targeting the miR-146b-5p/IL-6/STAT3 axis and may be a prognostic indicator of survival. Moreover, it can be a potential therapeutic target to enhance the efficacy of osimertinib in LUAD patients.

LncRNA DLEU1 is overexpressed in premature ovarian failure and sponges miR-146b-5p to increase granulosa cell apoptosis

Background

miR-146b-5p has been reported to participate in premature ovarian failure (POF) in mice. However, its role in POF patients is unclear. We predicted that miR-146b-5p might interact with lncRNA DLEU1, a crucial player in ovarian cancer. We then explored the interaction between DLEU1 and miR-146b-5p.

Methods

Expression of DLEU1 and miR-146b-5p in POF and control ovary tissues was determined by RT-qPCR. The subcellular location of DLEU1 in human KGN cells was analyzed using subcellular fractionation assays. The direct interaction between DLEU1 and miR-146b-5p was analyzed using RNA pull-down assays. The role of DLEU1 in miR-146a expression was analyzed using overexpression assay. Cell proliferation was analyzed using cell apoptosis assay.

Results

Increased DLEU1 expression and decreased miR-146b-5p expression were observed in POF. DLEU1 directly interacted with MiR-146b-5p and was expressed in both nuclear and cytoplasm samples of KGN cells. In KGN cells, DLEU1 and miR-146b-5p failed to regulate the expression of each other. However, DLEU1 promoted cell apoptosis and reduced the inhibitory effects of miR-146b-5p on cell apoptosis.

Conclusions

DLEU1 is overexpressed in POF and sponges miR-146b-5p to increase KGN cell apoptosis.

Depression of lncRNA MINCR antagonizes LPS-evoked acute injury and inflammatory response via miR-146b-5p and the TRAF6-NFkB signaling

BACKGROUND

Inflammation plays an important role in the development of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). The long non-coding RNA (lncRNA) MINCR is closely related to inflammation injury. This study was performed to explore the protective effects and mechanisms of MINCR in lipopolysaccharide (LPS)-induced lung injury and inflammation.

METHODS

The expression levels of MINCR and miR-146b-5p in lung tissue status were detected by using quantitative real-time polymerase chain reaction (qRT-PCR), hematoxylin and eosin staining, immunohistochemical staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Enzyme-linked immunosorbent assay and Western blotting analysis were used to detect the expression of inflammatory factors such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 in lung tissue. The relationship between MINCR, miR-146b-5p, and TRAF6 was explored using bioinformatics analysis and luciferase assay.

RESULTS

The expression levels of MINCR were increased in a mouse model of LPS-induced ALI and small airway epithelial cells (SAECs). shMINCR resulted in increased cell viability and decreased apoptosis, which protected against LPS-induced cell damage. shMINCR can inhibit the formation of neutrophil extracellular traps, neutrophil numbers, myeloperoxidase activity, and the production of inflammatory cytokines IL-6, IL-1β, and TNF-α induced by LPS. The silencing of miR-146b-5p reversed the effects of MINCR on LPS-induced lung damage. Sh-MINCR decreased the expression levels of TRAF6 and p-P65 in LPS-induced SAECs and lung tissues. Co-transfection of sh-MINCR with miR-146b-5p inhibitor reversed the effect of sh-MINCR on the expression of TRAF6 and p-P65.

CONCLUSIONS

MINCR may induce alveolar epithelial cell injury and inflammation and aggravate the progression of ALI/ARDS through miR-146b-5p and TRAF6/NF-κB pathways, which would provide a promising target for the treatment of ALI/ARDS.

MALAT1 Maintains the Intestinal Mucosal Homeostasis in Crohn's Disease via the miR-146b-5p-CLDN11/NUMB Pathway

BACKGROUND AND AIMS

Intestinal homeostasis disorder is critical for developing Crohn's disease [CD]. Maintaining mucosal barrier integrity is essential for intestinal homeostasis, preventing intestinal injury and complications. Among the remarkably altered long non-coding RNAs [lncRNAs] in CD, we aimed to investigate whether metastasis-associated lung adenocarcinoma transcript 1 [MALAT1] modulated CD and consequent disruption of intestinal homeostasis.

METHODS

Microarray analyses on intestinal mucosa of CD patients and controls were performed to identify dysregulated lncRNAs. MALAT1 expression was investigated via qRT-PCR and its distribution in intestinal tissues was detected using BaseScope. Intestines from MALAT1 knockout mice with colitis were investigated using histological, molecular, and biochemical approaches. Effects of intestinal epithelial cells, transfected with MALAT1 lentiviruses and Smart Silencer, on monolayer permeability and apical junction complex [AJC] proteins were analysed. MiR-146b-5p was confirmed as a critical MALAT1 mediator in cells transfected with miR-146b-5p mimic/inhibitor and in colitis mice administered agomir-146b-5p/antagomir-146b-5p. Interaction between MALAT1 and miR-146b-5p was predicted via bioinformatics and validated using Dual-luciferase reporter assay and Ago2-RIP.

RESULTS

MALAT1 was aberrantly downregulated in the intestine mucosa of CD patients and mice with experimental colitis. MALAT1 knockout mice were hypersensitive to DSS-induced experimental colitis. MALAT1 regulated the intestinal mucosal barrier and regained intestinal homeostasis by sequestering miR-146b-5p and maintaining the expression of the AJC proteins NUMB and CLDN11.

CONCLUSIONS

Downregulation of MALAT1 contributed to the pathogenesis of CD by disrupting AJC. Thus, a specific MALAT1-miR-146b-5p-NUMB/CLDN11 pathway that plays a vital role in maintaining intestinal mucosal homeostasis may serve as a novel target for CD treatment.

MiR-146b-5p targets IFI35 to inhibit inflammatory response and apoptosis via JAK1/STAT1 signalling in lipopolysaccharide-induced glomerular cells

The dysregulated microRNAs (miRNAs) are implicated in the malignancy of lupus nephritis (LN). This work aims to analyse the effect and mechanism of miR-146b-5p in lipopolysaccharides (LPS)-induced model of LN in vitro. The serum samples of LN patients and normal volunteers were collected. HK-2 cells were challenged via LPS. miR-146b-5p and interferon-induced protein 35 (IFI35) abundances were detected via quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. The inflammatory response was assessed via inflammatory cytokines levels via qRT-PCR and enzyme-linked immunosorbent assay. Cell apoptosis was analysed via flow cytometry and apoptotic protein levels. The protein levels of JAK1/STAT1 signalling were detected via western blot. The relationship of miR-146b-5p and IFI35 was analysed via bioinformatics and dual-luciferase reporter assays. This study revealed that miR-146b-5p level was declined and IFI35 abundance was elevated in serum of LN patients and LPS-challenged HK-2 cells. Functionally, IFI35 overexpression promoted LPS-caused inflammatory response and cell apoptosis, and knockdown of IFI35 caused an opposite trend. Meanwhile, miR-146b-5p targeted IFI35 to suppress inflammatory response and cell inflammatory response and apoptosis via inactivating the JAK1/STAT1 pathway. MiR-146b-5p suppressed inflammatory response and cell apoptosis by IFI35 mediated-JAK1/STAT1 signalling in HK-2 cells, which provided a new mechanism for understanding the pathogenesis of LN.

Lnc-STYK1-2 regulates bladder cancer cell proliferation, migration, and invasion by targeting miR-146b-5p expression and AKT/STAT3/NF-kB signaling

Background

Epigenetic modulation by noncoding RNAs substantially contributes to human cancer development, but noncoding RNAs involvement in bladder cancer remains poorly understood. This study investigated the role of long noncoding RNA (lncRNA) lnc-STYK1-2 in tumorigenesis in cancerous bladder cells.

Methods

Differential lncRNA and mRNA profiles were characterized by high-throughput RNA sequencing combined with validation via quantitative PCR. Bladder cancer cell proliferation was assessed through MTS, and bladder cancer cell migration and invasion were assessed through a Transwell system. The in vivo tumorigenesis of bladder cancer cells was evaluated using the cancer cell line-based xenograft model. The dual-luciferase reporter assay verified the association of miR-146b-5p with lnc-STYK1-2 and the target gene. Protein abundances and phosphorylation were detected by Western blotting.

Results

Alterations in lncRNA profiles, including decreased lnc-STYK1-2 expression, were detected in bladder cancer tissues compared with adjacent noncancerous tissues. lnc-STYK1-2 silencing effectively promoted proliferation, migration, and invasion in two bladder cancer cell lines, 5637 and T24, and their tumorigenesis in nude mice. lnc-STYK1-2 siRNA promoted miR-146b-5p and reduced ITGA2 expression in bladder cancer cells. Moreover, miR-146b-5p suppressed ITGA2 expression in bladder cancer cells through direct association. Also, lnc-STYK1-2 directly associated with miR-146b-5p. Finally, miR-146b-5p inhibitors abrogated the alterations in bladder cell functions, ITGA2 expression, and phosphorylation of AKT, STAT3, and P65 proteins in 5637 and T24 cells induced by lnc-STYK1-2 silencing.

Conclusion

lnc-STYK1-2 inhibited bladder cancer cell proliferation, migration, and tumorigenesis by targeting miR-146b-5p to regulate ITGA2 expression and AKT/STAT3/NF-kB signaling.

High-Throughput Sequencing of BACHD Mice Reveals Upregulation of Neuroprotective miRNAs at the Pre-Symptomatic Stage of Huntington's Disease

Huntington’s disease (HD) is a genetic disorder marked by transcriptional alterations that result in neuronal impairment and death. MicroRNAs (miRNAs) are non-coding RNAs involved in post-transcriptional regulation and fine-tuning of gene expression. Several studies identified altered miRNA expression in HD and other neurodegenerative diseases, however their roles in early stages of HD remain elusive. Here, we deep-sequenced miRNAs from the striatum of the HD mouse model, BACHD, at the age of 2 and 8 months, representing the pre-symptomatic and symptomatic stages of the disease. Our results show that 44 and 26 miRNAs were differentially expressed in 2- and 8-month-old BACHD mice, respectively, as compared to wild-type controls. Over-representation analysis suggested that miRNAs up-regulated in 2-month-old mice control the expression of genes crucial for PI3K-Akt and mTOR cell signaling pathways. Conversely, miRNAs regulating genes involved in neuronal disorders were down-regulated in 2-month-old BACHD mice. Interestingly, primary striatal neurons treated with anti-miRs targeting two up-regulated miRNAs, miR-449c-5p and miR-146b-5p, showed higher levels of cell death. Therefore, our results suggest that the miRNAs altered in 2-month-old BACHD mice regulate genes involved in the promotion of cell survival. Notably, over-representation suggested that targets of differentially expressed miRNAs at the age of 8 months were not significantly enriched for the same pathways. Together, our data shed light on the role of miRNAs in the initial stages of HD, suggesting a neuroprotective role as an attempt to maintain or reestablish cellular homeostasis.

The miR-146b-5p promotes Ewing's sarcoma cells progression via suppressing the expression of BTG2

Ewing sarcoma (ES) is a malignant tumor that occurs mostly in children. However, the underlying mechanisms of ES are still unknown. Analyzing the results of two previous miRNA array reports, we found that miR-146b-5p might be an onco-miRNA in ES progression. To test this hypothesis, we detected the expression levels of miR-146b-5p by real-time PCR and observed the effects of miR-146b-5p on the progression of ES cells by CCK8 and transwell assays. Bioinformatics and luciferase assays were used to identify the target genes of miR-146b-5p. It showed that the expression levels of miR-146b-5p were upregulated in ES cell lines compared with human mesenchymal stem cells (MSCs). Up- or downregulation of miR-146b-5p in ES cell lines could effectively promote or block the proliferation, migration, and invasion of ES cells, respectively. Furthermore, we demonstrated that BTG2 was one of the target genes and mediated the effects of miR-146b-5p in ES cells. Interestingly, we also found that miR-146b-5p was partly involved in the anticancer effects of pemetrexed in ES cells. Our study revealed that miR-146b-5p affected the progression of ES by suppressing BTG2, which might shed light on anticancer drug development and ES treatment in the future.

CASC9 plays a role in salivary adenoid cystic carcinoma in vitro by upregulation of ACLY

OBJECTIVE

The study was designed to explore the role of cancer susceptibility candidate 9 (CASC9) in salivary adenoid cystic carcinoma (SACC) (SACC-83 and SACC-LM) cell malignant phenotypes.

METHODS

Colony formation assay was used to measure cell proliferation. Transwell assay was used to detect cell migration and invasion. Flow cytometry analysis was applied to determine cell cycle distribution and apoptosis. FISH assay revealed the subcellular location of CASC9.

RESULTS

Downregulation of CASC9 inhibited SACC cell proliferation, migration, and invasion, led to cell arrest at G0/G1 phase, and facilitated cell apoptosis. In mechanism, CASC9 bound with microRNA 146b-5p (miR-146b-5p) and negatively modulated miR-146b-5p expression. MiR-146b-5p directly targeted 3' untranslated region of ATP-Citrate Lyase (ACLY) to degrade ACLY in SACC cells. CASC9 upregulated ACLY expression through competitively binding with miR-146b-5p. Furthermore, rescue assays indicated that ACLY overexpression counteracted the effects triggered by CASC9 knockdown on cell proliferation, migration, invasion, and apoptosis in SACC cells.

CONCLUSION

CASC9 facilitated the malignant phenotypes of SACC cells by the regulation of the miR-146b-5p/ACLY axis. These findings might lay foundation for SACC research.

miR-146b-5p regulates bone marrow mesenchymal stem cell differentiation by SIAH2/PPARγ in aplastic anemia children and benzene-induced aplastic anemia mouse model

This study aimed to reveal the mechanism of miR-146b-5p in the differentiation of bone marrow mesenchymal stem cells (BMSCs) derived from children with aplastic anemia (AA). Here, we found that miR-146b-5p was highly expressed in BMSCs from children with AA, and the BMSCs surface markers expressions in BMSCs derived from children with AA and the healthy controls exerted no significant differences. Besides, the overexpression of miR-146b-5p in normal human-derived BMSCs promoted the adipogenic differentiation of BMSCs. Furthermore, miR-146b-5p negatively regulated SIAH2 luciferase activity, and the interference with miR-146b-5p reduced the stability of PPARγ protein and inhibited SIAH2-mediated ubiquitination of PPARγ protein. Besides, the interference with miR-146b-5p was beneficial for ameliorating AA in a mouse model of AA. Overall, our results found that miR-146b-5p was highly expressed in BMSCs from children with AA, and our further studies indicated that miR-146b-5p improved AA via promoting SIAH2-mediated ubiquitination of PPARγ protein.

LncRNA-NEAT1 promotes proliferation of T-ALL cells via miR-146b-5p/NOTCH1 signaling pathway

BACKGROUND

T-cell acute lymphoblastic leukemia (T-ALL) is a malignant tumor of the hematopoietic system, which can develop at any age, with the symptoms of weakness, fatigue, enlarged lymph nodes, or weight loss. Nuclear paraspeckle assembly transcript 1 (NEAT1) is involved in the process of T-ALL, but the regulatory mechanism is still not known clearly.

METHODS

The expression levels of NEAT1 and miR-146b-5p in T-ALL cells were performed by qRT-PCR and NOTCH1 protein level- wwWwas determined by western blot assay. Dual-luciferase reporter assay was used to detect the interaction between NEAT1 and miR-146b-5p, as well as miR-146b-5p and NOTCH1. The cell proliferation was measured by using MTT assay and colony formation assay.

RESULTS

The expression levels of NEAT1 were markedly increased, but miR-146b-5p levels were reduced in T-ALL cells. Knockdown of NEAT1 or overexpression of miR-146b-5p decreased NOTCH1 expression, inhibited the proliferation of T-ALL cells. MiR-146b-5p bound both NEAT1 and NOTCH1 3'-UTR directly. Finally, inhibition of miR-146b-5p could abrogate the effects of NEAT1 knockdown on the proliferation of T-ALL cells.

CONCLUSION

NEAT1 promotes the proliferation of T-ALL cells by sponging miR-146b-5p to upregulate the expression of NOTCH1. The results of this study provide new insight into the action mechanism of NEAT1 modulating T-ALL progression.

Downregulation of miR-146b-5p via iodine involvement repressed papillary thyroid carcinoma cell proliferation

miR-146b-5p is overexpressed in papillary thyroid carcinoma (PTC) and is thought to be a related diagnostic marker. Previous studies have indicated the effects of iodine on oncogenic activation. However, the effect of iodine on the proliferation of PTC cells and the associated underlying mechanisms remain unclear. We found that miR-146b-5p was downregulated and smad4 was upregulated in patients exposed to high iodine concentration by in situ hybridisation (ISH) and immunohistochemical (IHC). NaI (10-3 M) treatment downregulated miR-146b-5p and upregulated Smad4 in PTC cell lines. Luciferase assay was used to confirm that Smad4 is a target of miR-146b-5p. Furthermore, MTT assay and cell cycle analysis indicated that 10-3 M NaI suppressed cell proliferation and caused G0/G1 phase arrest. Real-time PCR and Western blotting demonstrated that 10-3 M NaI increased p21, p27, and p57 levels and reduced cyclin D1 levels in PTC cells. Our findings suggest that 10-3 M NaI increases Smad4 levels through repression of miR-146b-5p expression, curbing the proliferation in PTC.

Overexpression of miR-146b-5p Ameliorates Neonatal Hypoxic Ischemic Encephalopathy by Inhibiting IRAK1/TRAF6/TAK1/NF-αB Signaling

PURPOSE

Neonatal hypoxic ischemic encephalopathy (HIE) is an essential factor underlying neonatal death and disability. This study sought to explore the role of miR-146b-5p in regulating neonatal HIE.

MATERIALS AND METHODS

In vitro and in vivo HIE models were established in PC12 cells and 10-day neonatal Sprague Dawley rats, respectively. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to assess miR-146b-5p expression and inflammatory factors [interleukin (IL)-6 and tumor necrosis factor (TNF)-α] in brain lesions and PC12 cells, while enzyme-linked immunosorbent assay was employed to detect the expression of oxidative stress factors (SOD and GSH-Px). Gain- and loss-assays of miR-146b-5p were conducted to verify its role in modulating the viability and apoptosis of PC12 cells under oxygen-glucose deprivation (OGD) treatment. Expression of TLR4, IRAK1, TRAF6, TAK1, and NF-κB were examined by qRT-PCR and/or Western blot. Dual luciferase activity assay was conducted to identify relationships between miR-146b-5p and IRAK1.

RESULTS

In the HIE models, significant oxidative stress and inflammatory responses emerged upon upregulation of TLR4/IRAK1/TRAF6/TAK1/NF-κB signaling. Overexpression of miR-146b-5p greatly inhibited OGD-induced PC12 cell injury, inflammatory responses, and oxidative stress. Inhibiting miR-146b-5p, however, had the opposite effects. IRAK1 was found to be a target of miR-146b-5p, and miR-146b-5p overexpression suppressed the activation of IRAK1/TRAF6/TAK1/NF-κB signaling.

CONCLUSION

This study demonstrated that miR-146b-5p overexpression alleviates HIE-induced neuron injury by inhibiting the IRAK1/TRAF6/TAK1/NF-κB pathway.

Long Non-Coding RNA NEAT1 Promotes the Proliferation, Migration, and Metastasis of Human Breast-Cancer Cells by Inhibiting miR-146b-5p Expression

Background

Breast cancer (BC) is the most commonly diagnosed cancer in women. Tumor recurrence and metastasis are the key causes of death in BC patients. Long non-coding RNA (lncRNA) is closely associated with BC progression. lncRNA nuclear-enriched abundant transcript (NEAT)1 has been reported to regulate the proliferation and mobility of several types of cancer cells. However, how lncRNA NEAT1 affects the proliferation and invasion of BC cells is not known.

Methods

Quantitative real time-polymerase chain reaction (qRT-PCR) was used to measure expression of lncRNA NEAT1 and microRNA (miR)-146b-5p in BC tissues and cell lines. Cell Counting Kit (CCK)-8, cell colony-formation, wound-healing, and Transwell™ assays were undertaken to determine the effects of lncRNA NEAT1 and miR-146b-5p on progression of BC cells. The interaction between lncRNA NEAT1 and miR-146b-5p was examined by luciferase reporter, RNA-binding protein immunoprecipitation (RIP), and RNA-pulldown assays.

Results

Expression of lncRNA NEAT1 was upregulated in BC tissues and cell lines. High expression of lncRNA NEAT1 predicted poor overall survival in BC patients. Silencing of expression of lncRNA NEAT1 inhibited epithelial–mesenchymal transition (EMT) and suppressed the proliferation, migration and invasion of BC cells. Ectopic expression of lncRNA NEAT1 induced EMT and promoted BC progression. Mechanistic investigations revealed that miR-146b-5p was a direct target of lncRNA NEAT1, and its expression was correlated negatively with expression of lncRNA NEAT1 in BC tissues.

Conclusion

lncRNA NEAT1 could (i) serve as a novel prognostic marker for BC and (ii) be a potential therapeutic target for BC.

MiR-146b-5p suppresses the malignancy of GSC/MSC fusion cells by targeting SMARCA5

Recent studies have confirmed that both cancer-associated bone marrow mesenchymal stem cells (BM-MSCs, MSCs) and glioma stem-like cells (GSCs) contribute to malignant progression of gliomas through their mutual interactions within the tumor microenvironment. However, the exact ways and relevant mechanisms involved in the actions of GSCs and MSCs within the glioma microenvironment are not fully understood. Using a dual-color fluorescence tracing model, our studies revealed that GSCs are able to spontaneously fuse with MSCs, yielding GSC/MSC fusion cells, which exhibited markedly enhanced proliferation and invasiveness. MiR-146b-5p was downregulated in the GSC/MSC fusion cells, and its overexpression suppressed proliferation, migration and invasion by the fusion cells. SMARCA5, which is highly expressed in high-grade gliomas, was a direct downstream target of miR-146b-5p in the GSC/MSC fusion cells. miR-146b-5p inhibited SMARCA5 expression and inactivated a TGF-β pathway, thereby decreasing GSC/MSC fusion cell proliferation, migration and invasion. Collectively, these findings demonstrate that miR-146b-5p suppresses the malignant phenotype of GSC/MSC fusion cells in the glioma microenvironment by targeting a SMARCA5-regulated TGF-β pathway.

WBSCR22 confers cell survival and predicts poor prognosis in glioma

Human WBSCR22 is involved in cancer proliferation, invasion and metastasis; however, its function in glioma remains unexplored. In our research, we aimed to investigate the role of WBSCR22 in the development of glioma and its possible molecular mechanisms. Using bioinformatic analysis of public datasets, we determined that WBSCR22 overexpression in glioma specimens was correlated with an unfavorable patient prognosis. Our results revealed that WBSCR22 was highly expressed in glioma cell lines. The loss of WBSCR22 inhibited the growth, invasion and migration of glioma cells, while WBSCR22 overexpression produced the opposite effects. Moreover, we found that WBSCR22 downregulation reduced the phosphorylation of Akt and GSK3β and decreased the levels of β-catenin and CyclinD1 in glioma cells. The opposite effects were observed when WBSCR22 was overexpressed. Additionally, we verified with a dual-luciferase reporter assay that WBSCR22 was a direct target of miR-146b-5p. Furthermore, overexpression of miR-146b-5p suppressed WBSCR22 mRNA and protein expression. Notably, the restoration of WBSCR22 expression remarkably reversed the effects of miR-146b-5p overexpression on cell survival, apoptosis and the cell cycle in glioma cells. Collectively, our findings revealed a tumor-promoting role for WBSCR22 in glioma cells, thus providing molecular evidence for WBSCR22 as a novel therapeutic target in glioma.

Sevoflurane suppresses migration and invasion of glioma cells by regulating miR-146b-5p and MMP16

Background: Glioma is the most common brain tumor with poor prognosis all over the world. Anesthetics have been demonstrated to have important impacts on cell migration and invasion in different cancers. However, the underlying mechanism that allows anesthetics-mediated progression of glioma cells remains elusive. Methods: Sevoflurane (Sev), a class of common anesthetics, was used to expose to U87-MG and U251 cells. The expressions of microRNA-146b-5p (miR-146b-5p) and matrix metallopeptidase 16 (MMP16)were measured by quantitative real-time polymerase chain reaction or western blot. Transfection was performed in glioma cells with miR-146b-5p inhibitor, inhibitor negative control, MMP16 overexpression vector, empty vector, small interfering RNA against MMP16 or scramble. Cell migration and invasion were analyzed by the trans-well assay. The interaction between miR-146b-5p and MMP16 was explored by luciferase activity and RNA immunoprecipitation assays. Results: Sev treatment inhibited migration and invasion of glioma cells. The expression of miR-146b-5p was enhanced and MMP16 protein was decreased in glioma cells after exposure of Sev. Knockdown of miR-146b-5p or overexpression of MMP16 reversed Sev-induced inhibition of migration and invasion of glioma cells. Moreover, MMP16 was indicated as a target of miR-146b-5p and its silencing attenuated the regulatory role of miR-146b-5p abrogationin Sev-treated glioma cells. Conclusion: Sev impeded cell migration and invasion through regulating miR-146b-5p and MMP16 in glioma, indicating a novel theories foundation for the application of anesthetics like Sev in glioma.

LncRNA SOX2-OT regulates proliferation and metastasis of nasopharyngeal carcinoma cells through miR-146b-5p/HNRNPA2B1 pathway

Nasopharyngeal carcinoma (NPC) is an aggressive malignancy with a high mortality on account of its frequent metastasis and poor prognosis. An extensive body of investigations has proven that long noncoding RNAs are implicated in a variety of biological processes. Although SOX2-OT has been reported to play an oncogenic role in osteosarcoma, the mechanism of SOX2-OT-driven NPC progression is still obscure. The aim of this study was to elucidate the biological function of SOX2-OT and the related possible mechanism in NPC. In our study, SOX2-OT was notably elevated in NPC samples and cells. Further, a high expression level of SOX2-OT was correlated with poor clinical outcomes of NPC. Results from loss-of-function experiments suggested that knockdown of SOX2-OT repressed cell proliferation, arrested cell cycle, facilitated cell apoptosis, and inhibited cell metastasis of NPC. To further investigate the molecular mechanism of SOX2-OT, miR-146b-5p was found to directly bind to SOX2-OT, which mediated the role of SOX2-OT in NPC tumorigenesis. In addition, HNRNPA2B1 was a target of miR-146b-5p and SOX2-OT modulated the expression of HNRNPA2B1 through competitively binding to miR-146b-5p. At last, we discovered that SOX2-OT regulated NPC progression by targeting miR-146b-5p/HNRNPA2B1 pathway, which may provide more innovative targets for the treatment of patients with NPC.

p16INK4a inhibits the proliferation of osteosarcoma cells through regulating the miR-146b-5p/TRAF6 pathway

Down-regulation of p16INK4a and miR-146b-5p contributes to tumorigenesis in osteosarcoma (OS). However, the correlation between p16INK4a and miR-146b-5p in OS proliferation remains largely unknown. In the present study, we demonstrated that miR-146b-5p expression was positively correlated with p16INK4a in OS, but inversely correlated with TNF receptor associated factor 6 (TRAF6) expression. Overexpression of miR-146b-5p dramatically suppressed OS cell proliferation. Mechanistically, we validated TRAF6 as a direct functional target of miR-146b-5p and found that miR-146b-5p overexpression significantly decreased the level of phosphorylated PI3k and Akt, which are the pivotal downstream effectors of TRAF6. Moreover, TRAF6 expression was positively correlated with Ki-67 but inversely correlated with miR-146b-5p expression. In OS cells, silencing of TRAF6 mimicked the anti-tumor effects of miR-146b-5p. p16INK4a is an important tumor suppressor gene frequently down-regulated in OS. We found that this inhibitory effect is associated with the suppression of the miR-146b-5p, and is mediated via up-regulating TRAF6 expression. Our findings identified p16INK4a and miR-146b-5p as tumor suppressors, and suggested p16INK4a, miR-146b-5p and TRAF6 as potential therapeutic candidates for malignant OS.

Inhibition of miR146b-5p suppresses CT-guided renal cell carcinoma by targeting TRAF6

Renal cell carcinoma (RCC) is one of the most common malignancies in the urinary system. Due to the lack of early symptoms, diagnosis of RCC usually occurs at late stages or after cancer metastasis leading to poor prognosis. Therefore, it is crucial to study early molecular mechanisms and biomarkers. Previous studies have suggested that microRNAs are involved in RCC initiation and development, making them a good candidate for early diagnosis and therapy. MiR146b-5P plays important roles in the progression of multiple cancers including thyroid cancer, pancreatic cancer, cervical cancer. However, it is not clear whether and how miR146b-5P is involved in RCC. In this study, we aimed to investigate the function of miR146b-5P in RCC. We examined the expression levels of miR146b-5p in renal cancer tissue and cell lines. We also explored the effects of blocking miR146b-5p in renal tumor growth and inflammatory signaling. Finally, we determined if miR146b-5p regulates tumorigenesis through TRAF6. We found that miR146b-5p levels were significantly increased in renal cancer tissue and renal cancer cells. Blocking miR146b-5p suppressed renal tumor growth and enhanced inflammatory response through increased TRAF6 expression. These effects were eliminated in TRAF6 knockout mice. Our results suggest that enhanced miR146b-5p expression may be a biomarker for RCC and modulating miR146b-5p and TRAF6 levels represent a potential therapeutic strategy for RCC.

MicroRNA-146b-3p Promotes Cell Metastasis by Directly Targeting NF2 in Human Papillary Thyroid Cancer

Background: MiR-146b has been reported to be overexpressed in papillary thyroid cancer (PTC) tissues and associated with aggressive PTC. MiR-146b is regarded as a relevant diagnostic marker for this type of cancer. MiR-146b-5p has been confirmed to increase cell proliferation by repressing SMAD4. However, detailed functional analysis of another mature form of miR-146b, miR-146b-3p, has not been carried out. This study aimed to identify the differential expression of miR-146b-5p and miR-146b-3p in more aggressive PTC associated with lymph node metastasis, and further elucidate the contribution and mechanism of miR-146b-3p in the process of PTC metastasis. Methods: Expression of miR-146b-5p and miR-146b-3p was assessed in formalin-fixed paraffin-embedded tissue samples from PTC patients, and the relationship with lymph node metastasis was analyzed. A variety of PTC cells, including BHP10-3, BHP10-3SC_mice, and K1 cells, were cultured and treated with miR-146b-5p or miR-146b-3p mimics/inhibitors. The cell migration and invasion abilities were characterized by the real-time cell analyzer assay and Transwell™ assay. PTC xenograft models were used to examine the effect of miR-146b-3p on PTC metastatic ability in vivo. Direct downstream targets of miR-146b-3p were analyzed by luciferase reporter assay and Western blotting. The mechanism by which miR-146b-3p affects cell metastasis was further characterized by co-transfection with merlin, the protein product of the NF2 gene. Results: MiR-146b-5p and miR-146b-3p expression was significantly higher in thyroid cancer tissues and cell lines than in normal thyroid tissue and cells. Moreover, expression of miR-146b-5p and miR-146b-3p was further increased in thyroid metastatic nodes than in thyroid cancer. After overexpression of miR-146b-5p or miR-146b-3p in BHP10-3 or K1 cells, PTC migration and invasion were increased. Notably, miR-146b-3p increased cell migration and invasion more obviously than did miR-146b-5p. Overexpression of miR-146b-3p also significantly promoted PTC tumor metastasis in vivo. Luciferase reporter assay results revealed that NF2 is a downstream target of miR-146b-3p in PTC cells, as miR-146b-3p bound directly to the 3' untranslated region of NF2, thus reducing protein levels of NF2. Overexpression of merlin reversed the enhanced aggressive effects of miR-146b-3p. Conclusions: Overexpression of miR-146b-5p and miR-146b-3p is associated with PTC metastasis. MiR-146b-3p enhances cell invasion and metastasis more obviously than miR-146b-5p through the suppression of the NF2 gene. These findings suggest a potential diagnostic and therapeutic value of these miRNAs in PTC metastasis.

Investigations on the mechanism of progesterone in inhibiting endometrial cancer cell cycle and viability via regulation of long noncoding RNA NEAT1/microRNA-146b-5p mediated Wnt/β-catenin signaling

Progesterone is often used to protect the endometrium and prevent endometrial cancer. An intensive study on its molecular mechanism in endometrial cancer would contribute to the development of more promising therapies. Relevant lncRNAs and mRNAs expression data in endometrial cancer cell line Ishikawa pretreated and post-treated with progesterone were derived from Gene Expression Omnibus (accession no. GSE29435), and then we analyzed long noncoding RNAs and mRNAs with differential expressions in two different conditions. The Cytoscape software, TargetScan, miRanda, and Human microRNA Disease Database (HMDD) websites were employed. Gene set enrichment analysis (GSEA) was used to determine related Kyoto Encyclopedia of Genes and Genomes pathways alteration in Ishikawa cells treated with progesterone. In addition to bioinformatics analysis, Reverse Transcription-Polymerase Chain Reaction (RT-PCR), Western blot, and dual-luciferase reporter assays were performed. The impact of progesterone on cell propagation and cell cycle was testified by colony formation and flow cytometry analysis. LncRNA nuclear enriched abundant transcript 1 (NEAT1) was the most significantly downregulated lncRNA in endometrial cancer cells treated with progesterone. Lymphoid enhancing factor 1 (LEF1) was positively associated with NEAT1, and eventually hsa_miR-146b-5p was validated to target both LEF1 and NEAT1. Wnt/β-catenin signaling pathway was identified to involve in endometrial cancer. NEAT1 or LEF1 was overexpressed in endometrial cancer cells while downregulated following post-treatment with progesterone. Conversely, miR-146b-5p was notably decreased in Ishikawa cells while upregulated after treatment with progesterone. Downstream gene c-myc or MMP9 regulated by upstream gene LEF1 in Wnt/β-catenin signaling pathway was remarkably increased in Ishikawa cells and positively related with NEAT1. Progesterone inhibited cell cycle and viability through regulating NEAT1/miR-146b-5p axis via Wnt/β-catenin signaling pathway. Progesterone exerted suppressive influence on endometrial cancer progression via regulation of lncRNA NEAT1/miR-146b-5p-mediated Wnt/β-catenin signaling pathway, which might reveal new strategies for developing more effective therapeutics. © 2018 IUBMB Life, 71(1):223-234, 2019.

Loss of miR-146b-5p promotes T cell acute lymphoblastic leukemia migration and invasion via the IL-17A pathway

Metastatic disease remains the primary cause of death for individuals with T cell acute lymphoblastic leukemia (T-ALL). microRNAs (miRNAs) play important roles in the pathogenesis of T-ALL by inhibiting gene expression at posttranscriptional levels. The goal of the current project is to identify any significant miRNAs in T-ALL metastasis. We observed miR-146b-5p to be downregulated in T-ALL patients and cell lines, and bioinformatics analysis implicated miR-146b-5p in the hematopoietic system. miR-146b-5p inhibited the migration and invasion in T-ALL cells. Interleukin-17A (IL-17A) was predicted to be a target of miR-146b-5p; this was confirmed by luciferase assays. Interestingly, T-ALL patients and cell lines secreted IL-17A and expressed the IL-17A receptor (IL-17RA). IL-17A/IL-17RA interactions promoted strong T-ALL cell migration and invasion responses. Gene set enrichment analysis (GSEA) and quantitative polymerase chain reaction (qPCR) analysis indicated that matrix metallopeptidase-9 (MMP9), was a potential downstream effector of IL-17A activation, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling was also implicated in this process. Moreover, IL-17A activation promoted T-ALL cell metastasis to the liver in IL17A ^-/- mouse models. These results indicate that reduced miR-146b-5p expression in T-ALL may lead to the upregulation of IL-17A, which then promotes T-ALL cell migration and invasion by upregulating MMP9 via NF-κB signaling.

HOXA11-AS promotes the growth and invasion of renal cancer by sponging miR-146b-5p to upregulate MMP16 expression

Recently, increasing studies showed that long noncoding RNAs (lncRNAs) play critical roles in tumor progression. However, the function and underlying mechanism of HOMEOBOX A11 antisense RNA (HOXA11-AS) on renal cancer remain unclear. In the current study, our data showed that the expression of HOXA11-AS was significantly upregulated in clear cell renal cell carcinoma (ccRCC) tissues and cell lines. High HOXA11-AS expression was associated with the advanced clinical stage, tumor stage, and lymph node metastasis. Function assays showed that HOXA11-AS inhibition significantly suppressed renal cancer cells growth, invasion, and ETM phenotype. In addition, underlying mechanism revealed that HOXA11-AS could act as a competing endogenous RNA (ceRNA) that repressed miR-146b-5p expression, which regulated its downstream target MMP16 in renal cancer. Taken together, our findings suggested that HOXA11-AS could promote renal cancer cells growth and invasion by modulating miR-146b-5p-MMP16 axis. Thus, our findings suggested that HOXA11-AS could serve as potential therapeutic target for the treatment of renal cancer.

MiR-146b-5p functions as a suppressor miRNA and prognosis predictor in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide. However, science has not yet been able to substantially improve the prognosis of lung cancer patients. Accumulating evidence suggests that microRNAs (miRNAs) are key players in the regulation of tumor development and metastasis. Expression of six miRNAs previously shown to play roles in tumor development (miR-146b-5p, miR-128b, miR-21, miR-221, miR-34a, and Let-7a) in other tumor types was examined using real-time RT-PCR in 78 specimens of NSCLC. The results revealed that patients with low expression of miR-146b-5p had significant shorter median and mean survival time than those with high miR-146b-5p expression (33.00 and 30.44 months versus 42.0 and 36.90 months, respectively; log-rank test P=0.048), thus low miR-146b-5p expression level was associated with poor prognosis in NSCLC patients. Univariate Cox hazard regression analysis demonstrated that miR-146b-5p expression levels tended to be a significant prognostic indicator of NSCLC (adjusted hazard ratio=0.482, 95% CI: 1.409- 29.593, P=0.016). Multivariate Cox proportional hazard regression analysis showed that miR-146b-5p expression levels were an independent prognostic factor for NSCLC patients (hazard ratio=0.259, 95% CI: 0.083-0.809, P=0.020). Furthermore, the effects of miR-146b-5p and miR-146b-3p on NSCLC cell growth and invasion in vitro were investigated. Our findings demonstrate that ectopic expression of miR-146b-5p suppressed cell proliferation, clonogenicity, migration/ invasion and also induced G1 arrest in vitro, but did not induce cell apoptosis; whereas enforced expression of miR-146b-3p did not have a significant effect on cell growth and metastasis. Further experiments indicated that miR-146b-5p could reduce mRNA levels of MMP16 and TRAF6 in vitro and was negatively related to the expression of TRAF6 in human NSCLC tissues. In a mouse model, Ago-miR-146b-5p could significantly inhibit the growth of lung cancer xenografts in nude mice. In conclusion, our findings demonstrate that miR-146b-5p functions as a suppressor miRNA and prognosis predictor in NSCLC.

miR-146b-5p regulates cell growth, invasion, and metabolism by targeting PDHB in colorectal cancer

MiRNA have been found to play a role in a plethora of cellular processes of cancer cells such as cell apoptosis, cell proliferation, invasion, migration metabolism and stem cell differentiation. Dysregulation of miR-146b-5p has been documented in a variety of human malignancies. However, the biological functions and molecular mechanisms of miR-146b-5p in ovarian cancer remain unknown. In this study, our results show that miR-146b-5p was unregulated in colorectal cancer (CRC) tissues compared with the adjacent non-cancerous tissues. Ectopic overexpression of miR-146b-5p in CRC promoted cell growth, invasion and glycolysis, while knockdown of miR-146b-5p inhibited the growth, invasion and glycolysis of CRC cells. The oncogenic effect of miR-146b-5p is also confirmed in vivo. Mechanically, miR-146b-5p targets the 3'-UTR of pyruvate dehydrogenase B (PDHB) and exerts oncogenic effect. Overexpression of PDHB abolished the oncogenic effects of miR-146b-5p on the growth, invasion and glycolysis of CRC cells. Taken together, our results show that miR-146b-5p is an oncogenic miRNA in CRC which exerts its effect by directly targeting PDHB.

[Down-regulation of miR-146b-5p promotes malignant transformation of fusion cells after co-culture of macrophages with glioma stem cells in vitro]

Objective: To observe mutual interactions between macrophages(Mφ) and glioma stem cells (GSCs)in dual-color tracing model in vitro, to identify the biological characteristics of fusion cells in multiple levels, and to analysis the relevant molecular mechanisms. Methods: Red fluorescent protein(RFP) gene was stably transfected into human GSCs cell line SU4. Mφ cells were obtained from Balb/c nude mice with enhanced green fluorescent protein (EGFP) expression. Then two cells were co-cultured in dual-color tracing platform. RFP/EGFP double positive cells with high proliferation ability were mono-cloned. The fusion cells were verified by Western blot, fluorescence in situ hybridization, immunocytochemistry and chromosome karyotype analysis.The biological characteristics of fusion cells were further analyzed, together with relevant molecular changes. Results: RFP / EGFP double positive cells were obtained through in vitro co-culture. RFP and EGFP coexpression were proved at transcriptional and translational levels in the fusion cells. They also co-expressed GSCs marker Nestin and Mφ marker CD68, and karyotype analysis showed two types of characteristic chromosomes, which confirmed that the fusion cells originated from spontaneous fusion between SU4-RFP and Mφ.Fusion cell proliferation rate and invasion ability were higher than SU4-RFP, which were relevant with down-regulation of miR-146b-5p and activation of STAT3. Fusion cells transfected with miR-146b-5p showed a higher apoptosis rate(18.83%) and lower tumor formation(4/5). Conclusion: Mφ could fuse with GSCs spontaneously in local tumor micro-environment. The proliferation and invasion abilities of fusion cells were higher than their parent cells, which were relevant with down-regulation of miR-146b-5p and activation of STAT3. It revealed the possible mechanisms of malignant progression of gliomas.

Screening the Expression Changes in MicroRNAs and Their Target Genes in Mature Cementoblasts Stimulated with Cyclic Tensile Stress

Cementum is a thin layer of cementoblast-produced mineralized tissue covering the root surfaces of teeth. Mechanical forces, which are produced during masticatory activity, play a paramount role in stimulating cementoblastogenesis, which thereby facilitates the maintenance, remodeling and integrity of cementum. However, hitherto, the extent to which a post-transcriptional modulation mechanism is involved in this process has rarely been reported. In this study, a mature murine cementoblast cell line OCCM-30 cells (immortalized osteocalcin positive cementoblasts) was cultured and subjected to cyclic tensile stress (0.5 Hz, 2000 µstrain). We showed that the cyclic tensile stress could not only rearrange the cell alignment, but also influence the proliferation in an S-shaped manner. Furthermore, cyclic tensile stress could significantly promote cementoblastogenesis-related genes, proteins and mineralized nodules. From the miRNA array analyses, we found that 60 and 103 miRNAs were significantly altered 6 and 18 h after the stimulation using cyclic tensile stress, respectively. Based on a literature review and bioinformatics analyses, we found that miR-146b-5p and its target gene Smad4 play an important role in this procedure. The upregulation of miR-146b-5p and downregulation of Smad4 induced by the tensile stress were further confirmed by qRT-PCR. The direct binding of miR-146b-5p to the three prime untranslated region (3' UTR) of Smad4 was established using a dual-luciferase reporter assay. Taken together, these results suggest an important involvement of miR-146b-5p and its target gene Smad4 in the cementoblastogenesis of mature cementoblasts.

miR-146b-5p mediates p16-dependent repression of IL-6 and suppresses paracrine procarcinogenic effects of breast stromal fibroblasts

Increasing evidence support the critical roles of active stromal fibroblasts in breast cancer development and spread. However, the mediators and the mechanisms of regulation are still not well defined. We have shown here that the tumor suppressor p16^INK4A protein inhibits the pro-carcinogenic effects of breast stromal fibroblasts through repressing the expression/secretion of IL-6. Indeed, p16^INK4A suppresses IL-6 at the mRNA and protein levels. This effect is mediated trough miR-146b-5p, which inhibits IL-6 expression through a specific sequence at the IL-6 3′UTR. In addition, we present clear evidence that miR-146b-5p inhibition is sufficient to transactivate breast stromal fibroblasts, which promote epithelial-to-mesenchymal-transition in breast cancer cells in a paracrine manner. By contrast, ectopic expression of miR-146b-5p in active fibroblasts abrogated their pro-carcinogenic effects. The physiological importance of miR-146b-5p inhibition was revealed by showing that the levels of pre-miR-146b-5p as well as its mature form are reduced in cancer-associated fibroblasts as compared with their normal adjacent counterparts from cancer-free tissues isolated from the same patients. Interestingly, treatment of active breast stromal fibroblasts with curcumin increased the level of the p16^INK4A coding CDKN2A mRNA and miR-146b-5p and suppressed IL-6, which confirms the repressive effect of these two tumor suppressor molecules on IL-6, and shows the possible “normalization” of cancer-related active fibroblasts. These results show that miR-146b-5p has non-cell-autonomous tumor suppressor function through inhibition of IL-6, suggesting that targeting this microRNA in breast stromal fibroblasts could be of great therapeutic value.

miR-146b-5p functions as a tumor suppressor by targeting TRAF6 and predicts the prognosis of human gliomas

Down-regulation of miR-146b-5p contributes to tumorigenesis in several human cancers. However, the relevance of miR-146b-5p to prognosis, proliferation and apoptosis in gliomas remains unknown. In the present study, we demonstrated that miR-146b-5p expression was inversely correlated with grades and Ki-67 index in 147 human glioma specimens, but positively correlated with patients’ survival. Furthermore, two distinct subgroups of patients with grade I-IV gliomas with different prognoses were identified according to miR-146b-5p expression in our specimens. Cox regression showed that miR-146b-5p was an independent predictor for patients’ survival. Overexpression of miR-146b-5p dramatically suppressed glioma cell proliferation and induced apoptosis. Mechanistically, we validated TRAF6 as a direct functional target of miR-146b-5p and found that miR-146b-5p overexpression significantly decreased phosphorylated TAK1 and IκBα, the pivotal downstream effectors of TRAF6. Moreover, TRAF6 expression was positively correlated with glioma grades and Ki-67 index but inversely correlated with miR-146b-5p expression and predicted poor prognosis of glioma patients. In glioblastoma cell lines, silencing of TRAF6 could mimic the anti-tumor effect of miR-146b-5p. Our findings identify miR-146b-5p as a tumor suppressor and novel prognostic biomarker of gliomas, and suggest miR-146b-5p and TRAF6 as potential therapeutic candidates for malignant gliomas.

miR-146b-5p promotes VSMC proliferation and migration

Vascular smooth muscle cells (VSMCs) play pivotal roles in the development of vascular diseases. While microRNAs are important in vascular pathologies, a few is known about their functional roles in VSMC phenotypes. We profiled microRNA expression in PDGF-BB treated VSMCs and found microRNA-146b-5p (miR-146b-5p) was upregulated. Inhibition of miR-146b-5p blocked in response to PDGF while reducing VSMC proliferation and migration. These studies implicate miR-146b-5p as necessary for PDGF-induced VSMC phenotype transition. Downstream miR-146b-5p targets modulating VSMC phenotypes will be further identified. Our study will help to understand the role of VSMCs in the pathology of vascular diseases.

MicroRNA-141 and microRNA-146b-5p inhibit the prometastatic mesenchymal characteristics through the RNA-binding protein AUF1 targeting the transcription factor ZEB1 and the protein kinase AKT

miR-141 and miR-146b-5p are two important tumor suppressor microRNAs, which control several cancer-related genes and processes. In the present report, we have shown that these microRNAs bind specific sites at the 3'-untranslated region (UTR) of the mRNA-binding protein AUF1, leading to its down-regulation. This inverse correlation between the levels of these microRNAs and AUF1 has been identified in various osteosarcoma cell lines. Additionally, we present clear evidence that AUF1 promotes mesenchymal features in osteosarcoma cells and that miR-141 and miR-146b-5p suppress this prometastatic process through AUF1 repression. Indeed, both microRNAs suppressed the invasion/migration and proliferation abilities of osteosarcoma cells through inhibiting the AKT protein kinase in an AUF1-dependent manner. We have also shown that AUF1 binds to and stabilizes the mRNA of the AKT activator phosphoinositide-dependent kinase-1 (PDK1). Furthermore, miR-141 and miR-146b-5p positively regulate the epithelial markers (E-cadherin and Epcam) and repress the mesenchymal markers (N-cadherin, Vimentin, Twist2, and ZEB1). These effects were mediated via the repression of the epithelial-to-mesenchymal inducer ZEB1 through targeting AUF1, which binds the 3'-UTR of the ZEB1 mRNA and reduces its turnover. These results indicate that at least some tumor suppressor functions of miR-141 and miR-146b-5p are mediated through the repression of the oncogenic potentials of AUF1. Therefore, these 3'-UTR-directed post-transcriptional gene expression regulators constitute promising new targets for diagnostic and/or therapeutic interventions.

miR-146b-5p inhibits glioma migration and invasion by targeting MMP16

miR-146b-5p is frequently down-regulated in solid tumours, including prostate cancer, pancreatic cancer, and glioblastoma. However, the tumour-suppressive effects of miR-146b-5p in malignant gliomas have not been investigated thoroughly. Here, we found that decreased miR-146b-5p expression was strongly correlated with chromosome 10q loss in gliomas, especially glioblastomas. The overexpression of miR-146b-5p in glioblastoma cell lines led to MMP16 mRNA silencing, MMP2 inactivation, and the inhibition of tumour cell migration and invasion. Our results suggest that the restoration of miR-146b-5p expression may be a feasible approach for inhibiting the migration and invasion of malignant gliomas.