Suppressed Glioma Cell Proliferation Research Articles

Inhibition of chromosomal region maintenance 1 suppresses the migration and invasion of glioma cells via inactivation of the STAT3/MMP2 signaling pathway.

Chromosomal region maintenance 1 (CRM1) is associated with an adverse prognosis in glioma. We previously reported that CRM1 inhibition suppressed glioma cell proliferation both in vitro and in vivo. In this study, we investigated the role of CRM1 in the migration and invasion of glioma cells. S109, a novel reversible selective inhibitor of CRM1, was used to treat Human glioma U87 and U251 cells. Cell migration and invasion were evaluated by wound-healing and transwell invasion assays. The results showed that S109 significantly inhibited the migration and invasion of U87 and U251 cells. However, mutation of Cys528 in CRM1 abolished the inhibitory activity of S109 in glioma cells. Furthermore, we found that S109 treatment decreased the expression level and activity of MMP2 and reduced the level of phosphorylated STAT3 but not total STAT3. Therefore, the inhibition of migration and invasion induced by S109 may be associated with the downregulation of MMP2 activity and expression, and inactivation of the STAT3 signaling pathway. These results support our previous conclusion that inhibition of CRM1 is an attractive strategy for the treatment of glioma.

Clinical significance of miR-33b in glioma and its regulatory role in tumor cell proliferation, invasion and migration.

Background: This study aimed to investigate the clinical significance of microRNA-33b (miR-33b) in glioma patients and its biological function in tumor progression. Materials & methods: Expression of miR-33b was measured using quantitative real-time RT-PCR. Diagnostic and prognostic values of miR-33b were assessed by the receiver operating characteristics curve and Kaplan-Meier (KM) survival assay. The functional role of miR-33b was further analyzed. Results: Expression of miR-33b in glioma patients and cells was decreased. Expression of miR-33b had high diagnostic accuracy and could predict a poor prognosis. Overexpression of miR-33b led to suppressed glioma cell proliferation, migration and invasion. Conclusion: Decreased expression of miR-33b serves a promising biomarker in the diagnosis and prognosis of glioma, and may be a potential therapeutic target.

MicroRNA-144 represses gliomas progression and elevates susceptibility to Temozolomide by targeting CAV2 and FGF7

Malignant gliomas are the most common tumor in central nervous system with poor prognosis. Due to the limitation of histological classification in earlier diagnosis and individualized medicine, it is necessary to combine the molecular signatures and the pathological characteristics of gliomas. Lots of microRNAs presented abnormal expression in gliomas and modulated gliomas development. Exploration the miRNAs profile is helpful for the diagnosis, therapy and prognosis of gliomas. It has been demonstrated that miR-144 plays important roles in solid tumors. However, the detail mechanisms remained unrevealed. In this study, we have demonstrated the level of miR-144 decreased in glioma tissues from patients, especially in gliomas with higher grades. MiR-144 was also validated have lower expression in glioma cell lines compared with cortical neuron cell by using qRT-PCR. The in vitro functional experiment indicated miR-144 improved gliomas progression through repressing proliferation, sensitizing to chemotherapeutics and inhibiting metastasis. We further identified fibroblast growth factor 7 (FGF7) and Caveolin 2 (CAV2) were target genes of miR-144 by luciferase reporter assay and western blotting. The mechanisms study suggested forced FGF7 expression elevated Akt activation and decreased reactive oxygen species (ROS) generation. The MTT and cell cycle assay indicated miR-144 suppressed glioma cells proliferation through modulating FGF mediated Akt signaling pathway. Meanwhile, miR-144 promoted Temozolomide (TMZ) induced apoptosis in glioma cells via increasing ROS production by using FACS. On the other hand, CAV2, as another target of miR-144, accelerated glioma cells migration and invasion via promoting glioma cells EMT progress. Retrieved expression of FGF7 or CAV2 rescued the proliferation and migration function mediated by miR-144. Furthermore, the in vivo experiments in PDX models displayed the anti-tumor function of miR-144, which could be retrieved by overexpression of FGF7 and CAV2. Taken together, these findings indicated miR-144 acted as a potential target against gliomas progression and uncovered a novel regulatory mechanism, which may provide a new therapeutic strategy and prognostic indicator for gliomas.

ACT001 modulates the NF-κB/MnSOD/ROS axis by targeting IKKβ to inhibit glioblastoma cell growth.

Glioblastomas are high-grade brain tumors with poor prognoses, and new therapeutic approaches for these tumors are critically needed. This study revealed the underlying mechanisms of a new orphan drug, ACT001, that is currently in clinical trials for the treatment of advanced glioblastoma in Australia and China. ACT001 significantly suppressed glioma cell proliferation and induced apoptosis and cell cycle arrest in vitro, as determined by Cell Counting Kit-8 assays and flow cytometry. In addition, U-118 MG cells with high expression of p-IKKβ were sensitive to ACT001. Changes in the oxidative stress pathway in U-118 MG cells were detected with the isobaric tags for relative and absolute quantitation (iTRAQ) method. We further verified that ACT001 elevated the levels of reactive oxygen species (ROS) by regulating NF-κB-targeted MnSOD. ACT001 markedly inhibited NF-κB activation by directly binding IKKβ and inhibiting its phosphorylation. Overexpression of IKKβ markedly attenuated the changes in MnSOD and NOX1, indicating that ACT001 increased the levels of ROS by reducing the protein expression of p-IKKβ. Furthermore, ACT001 reduced cyclin B1/CDC2 expression and triggered G2/M phase arrest by increasing ROS production. ACT001 also upregulated the expression of Bax and Bim and induced apoptosis in a ROS-dependent manner. ACT001 effectively suppressed the growth of U-118 MG tumors in BALB/c nude mice and GL-261-luciferase tumors in C57BL/6 J mice. Finally, ACT001 downregulated the expression of p-p65, MnSOD, cyclin B1, CDC2, and Ki67 in U-118 MG tumor tissues. Patients with activated NF-κB signaling should thus be given priority for enrollment in future phase II clinical trials. KEY MESSAGES: ACT001 directly bind to IKKβ and inhibited its phosphorylation. The inhibition of p-IKKβ induced the generation of ROS. ACT001 promoted the generation of ROS by regulating MnSOD expression to induce G2/M phase arrest.

Long intergenic non-protein coding RNA 00475 silencing acts as a tumor suppressor in glioma under hypoxic condition by impairing microRNA-449b-5p-dependent AGAP2 up-regulation.

Objective:Long non-coding RNAs have been demonstrated to be involved in the progression of a variety of cancers, including glioma. Through microarray analyses, long intergenic non-protein coding RNA 00475 (LINC00475) was identified in the glioma development. However, its potential role remains incompletely understood. This study aimed to elucidate the effect of LINC00475 on the development of glioma under hypoxic conditions.Methods:Glioma cells underwent hypoxic treatment and were collected. The functional role of LINC00475 and AGAP2 in glioma was determined using ectopic expression, depletion, and reporter assay experiments. Then, the expression of LINC00475, microRNA (miR)-449b-5p, AGAP2, FAK, and HIF-1α was determined. In addition, cell migration and invasion were examined. Finally, a tumor xenograft was carried out in nude mice to explore the role of LINC00475 on oxidation in vivo.Results:LINC00475 was identified to be overexpressed in hypoxic glioma samples, which was further observed to bind to and down-regulate miR-449b-5p, and negatively targeted AGAP2. Moreover, we also revealed a positive correlation between LINC00475 and AGAP2 expression in glioma. In addition, silencing of LINC00475 decreased the extent of FAK phosphorylation and reduced the expression of HIF-1α and AGAP2. It was also observed that LINC00475 silencing suppressed glioma cell proliferation, migration, and invasion, and promoted cell apoptosis. Moreover, oxidation of nude mice was promoted by LINC00475 silencing.Conclusion:Taken together, LINC00475 silencing exerted an inhibitory effect on glioma under hypoxic conditions by down-regulating AGAP2 via up-regulation of miR-449b-5p.

TRPM7 Induces Mechanistic Target of Rap1b Through the Downregulation of miR-28-5p in Glioma Proliferation and Invasion.

Objectives: Our previous findings demonstrate that channel-kinase transient receptor potential (TRP) ion channel subfamily M, member 7 (TRPM7) is critical in regulating human glioma cell migration and invasion. Since microRNAs (miRNAs) participate in complex regulatory networks that may affect almost every cellular and molecular process during glioma formation and progression, we explored the role of miRNAs in human glioma progression by comparing miRNA expression profiles due to differentially expressed TRPM7.Methods: First, we performed miRNA microarray analysis to determine TRPM7's miRNA targets upon TRPM7 silencing in A172 cells and validated the miRNA microarray data using A172, U87MG, U373MG, and SNB19 cell lines by stem-loop RT-qPCRs. We next determined whether TRPM7 regulates glioma cell proliferation and migration/invasion through different functional domains by overexpressing wild-type human TRPM7 (wtTRPM7), two mutants with TRPM7's α-kinase domain deleted (Δkinase-DK), or a point mutation in the ATP binding site of the α-kinase domain (K1648R-KR). In addition, we determined the roles of miR-28-5p in glioma cell proliferation and invasion by overexpressing or under expressing miR-28-5p in vitro. Lastly, we determined whether a Ras-related small GTP-binding protein (Rap1b) is a target of miR-28-5p in glioma tumorigenesis.Results: The miRNA microarray data revealed a list of 16 downregulated and 10 upregulated miRNAs whose transcripts are significantly changed by TRPM7 knock-down. Cell invasion was significantly reduced in two TRPM7 mutants with inactive kinase domain, Δkinase, and K1648R transfected glioma cells. miR-28-5p overexpression suppressed glioma cells' proliferation and invasion, and miR-28-5p under expression led to a significant increase in glioma cell proliferation and migration/invasion compared to that of the controls. miR-28-5p suppressed glioma cell proliferation and migration by targeting Rap1b. Co-transfection of siRap1b with miR28-5p inhibitor reduced the glioma cell proliferation and invasion, caused by the latter.Conclusions: These results indicate that TRPM7's channel activity is required for glioma cell growth while the kinase domain is required for cell migration/invasion. TRPM7 regulates miR-28-5p expression, which suppresses cell proliferation and invasion in glioma cells by targeting Rap1b signaling.

DGCR8/ZFAT-AS1 Promotes CDX2 Transcription in a PRC2 Complex-Dependent Manner to Facilitate the Malignant Biological Behavior of Glioma Cells.

Studies have found that RNA-binding proteins (RBPs) and long non-coding RNAs (lncRNAs) are dysregulated and play an important regulatory role in the development of tumors. Based on The Cancer Genome Atlas (TCGA) database, our findings from experiments, and the evidence of previous studies, we screened DiGeorge syndrome critical region gene 8 (DGCR8), ZFAT antisense RNA 1 (ZFAT-AS1), and caudal type homeobox 2 (CDX2) as research candidates. In the present study, DGCR8 and CDX2 were highly expressed and ZFAT-AS1 was markedly downregulated in glioma tissues and cells. DGCR8 or CDX2 knockdown or ZFAT-AS1 overexpression suppressed glioma cell proliferation, migration, and invasion and facilitated apoptosis. DGCR8 might decrease ZFAT-AS1 expression by attenuating its stability in a manner of inducing its cleavage. Importantly, ZFAT-AS1 could inhibit CDX2 transcription by mediating the methylation of histone H3 on lysine 27 (H3K27me3) modification induced by PRC2 in the CDX2 promoter region. In addition, CDX2 transcriptionally activated DGCR8 expression by binding to its promoter regions, forming a positive feedback loop of DGCR8/ZFAT-AS1/CDX2. In conclusion, DGCR8/ZFAT-AS1 promotes CDX2 transcription in a PRC2 complex-dependent manner to facilitate the malignant biological behavior of glioma cells.

MicroRNA-199a-5p regulates glioma progression via targeting MARCH8.

MicroRNA-199a-5p (miR-199a-5p) was reported to play crucial roles in cancer progression. However, its role in glioma remains largely unknown. RT-qPCR was employed to analyze miR-199a-5p expression level in glioma cell lines. The effects of miR-199a-5p on cell proliferation and invasion were investigated in vitro. We showed that miR-199a-5p expression level was significantly downregulated in glioma cell lines compared with a normal cell. In addition, miR-199a-5p overexpression suppresses glioma cell proliferation and invasion in vitro. Bioinformatic analysis and Luciferase assay suggested that the membrane-associated ring-CH-type finger 8 (MARCH8) was a target of miR-199a-5p. Furthermore, MARCH8 overexpression could partially reverse the effects of miR-199a-5p on glioma cells. These findings suggested that miR-199a-5p may function as a tumor suppressor in glioma by targeting MARCH8.

Low microRNA-622 expression predicts poor prognosis and is associated with ZEB2 in glioma.

BackgroundMicroRNAs have been recently reported to play an important role in tumorigenesis and progression in several forms of tumors. Previous studies have shown that microRNA-622 (miR-622) was associated with glioma proliferation and invasion. However, the clinical significance of miR-622 in glioma has not been elucidated. The aim of our study was to investigate the clinical values of miR-622, as well as investigate the potential molecular mechanisms in glioma.Materials and methodsqRT-PCR and Western blot analysis were used to analyze the expression of miR-622 and ZEB2, respectively. Kaplan–Meier analysis and Cox’s proportional hazards model were used in survival analysis. MTT assay, wound healing assay, transwell assay and flow cytometry analysis were carried out to detect the impact of miR-622 on glioma cell proliferation, migration, invasion and apoptosis.ResultsOur result indicated that miR-622 expression was greatly decreased in glioma tissues and cell lines and the downregulation of miR-622 was significantly associated with the advanced pathological grade and low Karnofsky performance score of glioma. In addition, Kaplan–Meier curves with log-rank analysis revealed a close correlation between downregulation of miR-622 expression and low overall survival rate in glioma patients. Furthermore, Cox regression analysis demonstrated that downregulated miR-622 could be considered as an independent poor prognostic indicator in glioma patients. Finally, our findings demonstrated that miR-622 overexpression remarkably suppressed glioma cell proliferation, migration and invasion, while facilitated apoptosis by suppressing ZEB2 in vitro.ConclusionOur study suggested that miR-622 may be identified as a valuable prognostic biomarker and a promising therapeutic target for glioma patients.

LINC00052 suppressed glioma cell proliferation and invasion by downregulating insulin-like growth factor 2

Background: Recent studies have discovered a subtype of noncoding RNAs, long noncoding RNAs (lncRNAs), which are dysregulated in various tumors and associated with carcinogenesis. This study aims to identify the role of lncRNA LINC00052 in glioma tumorigenesis. Methods: LINC00052 expression was monitored in glioma samples and glioma cells through RT-qPCR. Besides, proliferation assay, transwell assay and wound healing assay were performed to uncover the role of LINC00052 in glioma. Furthermore, the interaction between LINC00052 and insulin-like growth factor 2 (IGF2) in glioma was studied through RT-qPCR and western blot assay. Results: LINC00052 expression was remarkably downregulated in glioma samples compared with that in normal brain samples. Moreover, cell proliferation, cell invasion and cell migration in glioma were inhibited after overexpression of LINC00052 in vitro . Moreover, after overexpression of LINC00052, IGF2 was downregulated at mRNA and protein level in vitro . Besides, the expression of IGF2 in tumor tissues was negatively correlated to the expression of LINC00052. Conclusions: These results above suggest that LINC00052 could repress cell migration, invasion and proliferation in glioma through downregulating IGF2, which may offer a new therapeutic intervention for glioma patients.

LINC00052 suppressed glioma cell proliferation and invasion by downregulating insulin-like growth factor 2.

BackgroundRecent studies have discovered a subtype of noncoding RNAs, long noncoding RNAs (lncRNAs), which are dysregulated in various tumors and associated with carcinogenesis. This study aims to identify the role of lncRNA LINC00052 in glioma tumorigenesis.MethodsLINC00052 expression was monitored in glioma samples and glioma cells through RT-qPCR. Besides, proliferation assay, transwell assay and wound healing assay were performed to uncover the role of LINC00052 in glioma. Furthermore, the interaction between LINC00052 and insulin-like growth factor 2 (IGF2) in glioma was studied through RT-qPCR and western blot assay.ResultsLINC00052 expression was remarkably downregulated in glioma samples compared with that in normal brain samples. Moreover, cell proliferation, cell invasion and cell migration in glioma were inhibited after overexpression of LINC00052 in vitro. Moreover, after overexpression of LINC00052, IGF2 was downregulated at mRNA and protein level in vitro. Besides, the expression of IGF2 in tumor tissues was negatively correlated to the expression of LINC00052.ConclusionsThese results above suggest that LINC00052 could repress cell migration, invasion and proliferation in glioma through downregulating IGF2, which may offer a new therapeutic intervention for glioma patients.

Knockdown ATG4C inhibits gliomas progression and promotes temozolomide chemosensitivity by suppressing autophagic flux

BackgroundGliomas are the most common primary tumors in central nervous system. Despite advances in diagnosis and therapy, the prognosis of glioma remains gloomy. Autophagy is a cellular catabolic process that degrades proteins and damaged organelles, which is implicated in tumorigenesis and tumor progression. Autophagy related 4C cysteine peptidase (ATG4C) is an autophagy regulator responsible for cleaving of pro-LC3 and delipidation of LC3 II. This study was designed to investigate the role of ATG4C in glioma progression and temozolomide (TMZ) chemosensitivity.MethodsThe association between ATG4C mRNA expression and prognosis of gliomas patients was analyzed using the TCGA datasets. The role of ATG4C in proliferation, apoptosis, autophagy, and TMZ chemosensitivity were investigated by silencing ATG4C in vivo. Ectopic xenograft nude mice model was established to investigate the effects of ATG4C on glioma growth in vivo.ResultsThe median overall survival (OS) time of patients with higher ATG4C expression was significantly reduced (HR: 1.48, p = 9.91 × 10− 7). ATG4C mRNA expression was evidently increased with the rising of glioma grade (p = 2.97 × 10− 8). Knockdown ATG4C suppressed glioma cells proliferation by inducing cell cycle arrest at G1 phase. ATG4C depletion suppressed autophagy and triggered apoptosis through ROS accumulation. Depletion of ATG4C suppressed TMZ-activated autophagy and promoted sensitivity of glioma cells to TMZ. Additionally, ATG4C knockdown suppressed the growth of glioma remarkably in nude mice.ConclusionATG4C is a potential prognostic predictor for glioma patient. Targeting ATG4C may provide promising therapy strategies for gliomas treatment.

Circular RNA circ_0079593 indicates a poor prognosis and facilitates cell growth and invasion by sponging miR-182 and miR-433 in glioma.

Glioma is one of the major global health problems, including in China. Circular RNAs (circRNAs) have been increasingly identified and characterized in almost every aspect of biology, especially in cancer biology. This research desires to explore the functions and mechanism of a novel circRNA, circ_0079593, on regulating glioma progression. Quantitative real-time polymerase chain reaction (qRT-PCR) was carried out to measure the relative expression of circ_0079593, which was upregulated in matched cancerous tissues from 60 patients and four cell lines of glioma. A higher level of circ_0079593 in glioma specimens was linked to larger tumor size, higher WHO grade, and worse survival rate for patients with glioma. Moreover, circ_0079593 can be deemed as an independent prognostic predictor for glioma patients analyzed by multivariate method. Cell counting kit-8, flow cytometric, wound healing, and transwell experiments were used to evaluate cell growth, apoptosis, migration, and invasion influenced by circ_0079593 knockdown/overexpression. Exogenous downregulation of circ_0079593 expression significantly suppressed glioma cell proliferation by increasing cell apoptosis in vitro, and retarded the migratory and invasive potential. Ectopic expressed circ_0079593 could induce the opposite effects. Mechanistically, bioinformatics analysis, qRT-PCR, and dual-luciferase reporter assays showed that microRNA 182 (miR-182) and miR-433 could be sponged and negatively regulated by circ_0079593. Further, rescue assays demonstrated that the biological functions of circ_0079593 are dependent on its inhibition of miR-182 and miR-433. Collectively, the present work indicates that circ_0079593 may be used as an effective prognostic marker and therapeutic target for glioma.

MicroRNA-10b-5p downregulation inhibits the invasion of glioma cells via modulating homeobox B3 expression.

MicroRNA-10b (miR-10b) has been reported to be specifically upregulated in glioma tissues and cell lines. The aim of the present study was to investigate the effect of miR-10b-5p on the proliferation and invasion of glioma cells, and the possible underlying molecular mechanism. Cell viability was evaluated using an MTT assay, and flow cytometry was performed for cell cycle analysis. The effects of miR-10b-5p on glioma cell migration and invasion were assessed using wound healing and Transwell assays, respectively. The activity of matrix metalloproteinase 2 (MMP2) was also determined using zymography. Furthermore, homeobox B3 (HOXB3) mRNA expression in glioma cells was examined using quantitative polymerase chain reaction analysis. The protein expression levels of HOXB3, high mobility group box 1 (HMGB1) and Ras homolog family member C (RhoC) were further measured using western blotting. It was observed that glioma cells transfected with miR-10b-5p inhibitor exhibited significantly decreased proliferation. The wound healing and Transwell assays demonstrated that the miR-10b-5p inhibitor reduced the ability of glioma cells to migrate and invade, while transfection with miR-10b-5p mimic exhibited the opposite effect. HOXB3 was downregulated by miR-10b-5p at both the mRNA and protein levels. In addition, the expression of proteins associated with migration and invasion, including HMGB1, RhoC and MMP2, was upregulated in glioma cells transfected with miR-10b-5p mimic, while these proteins were downregulated in cells transfected with miR-10b-5p inhibitor. Taken together, the findings of the present study indicated that miR-10b-5p downregulation suppressed glioma cell proliferation and invasion, possibly by modulating HOXB3, which may provide a novel bio-target for glioma therapy.

IL1RN mediates the suppressive effect of methionine deprivation on glioma proliferation.

Metabolic abnormality is one of the hallmarks of cancer cells, and limiting material supply is a potential breakthrough approach for cancer treatment. Increasing researchers have been involved in the study of glioma cell metabolism reprogramming since the significance of IDH1 was confirmed in glioma. However, the molecular mechanisms underlying metabolic reprogramming induced by methionine deprivation regulates glioma cell proliferation remain unclear. Here we demonstrated that methionine deprivation inhibited glioma cell proliferation via downregulating interleukin 1 receptor antagonist (IL1RN) both in vitro and in vivo, methionine deprivation or knocking down IL1RN induced glioma cell cycle arrest. Moreover, we confirmed that IL1RN is a tumor associated gene and its expression is negatively correlated with the survival time of glioma patients. Altogether these results demonstrate a strong rationale insight that targeting amino acid metabolism such as methionine deprivation/IL1RN related gene therapy may offer novel direction for glioma treatment.

LncRNA CASC7 inhibits the progression of glioma via regulating Wnt/β-catenin signaling pathway

Increasing evidence reveal the important role of long non-coding RNAs (lncRNAs) in the initiation and progression of glioma. However, the role of lncRNA cancer susceptibility candidate 7 (CASC7) in glioma is largely unknown. At first, the expression level of CASC7 was tested in glioma tissues and cell lines by using qRT-PCR. We applied Kaplan-Meier method to analyze the correlation between the expression level between CASC7 expression and the overall survival rate of glioma patients. We found that CASC7 was downregulated in glioma tissues and cell liens and predicted poor prognosis for patients with glioma. To determine the involvement of CASC7 in the biological processes of glioma, we conducted gain or loss-of function assays in two glioma patients. We found that CASC7 suppressed glioma cell proliferation and induced glioma cell apoptosis. Mechanistically, the expression level of CASC7 was negatively correlated with the expression levels of core factors of Wnt/β-catenin signaling pathway in glioma cells. Moreover, TOP flash luciferase activity further revealed the negative effect of CASC7 on the activity of Wnt/β-catenin signaling pathway. Finally, rescue assays were carried out to determine that Wnt/β-catenin signaling pathway involved in CASC7-mediated glioma progression. Taken together, all research findings suggested that CASC7 inhibited the progression of glioma via regulating Wnt/β-catenin signaling pathway.

Long noncoding FOXD2-AS1 is activated by CREB1 and promotes cell proliferation and metastasis in glioma by sponging miR-185 through targeting AKT1

Long non-coding RNA FOXD2-AS1 (FOXD2-AS1) has been reported to be involved in several tumors as a potential oncogene. However, its expression pattern and biological function in glioma have not been investigated. In this study, we found that FOXD2-AS1 expression was significantly up-regulated in both glioma tissues and cell lines. Additionally, CREB1 could bind directly to the FOXD2-AS1 promoter region and activate its transcription. High FOXD2-AS1 expression was significantly correlated with advanced WHO grade, KPS score and the shorter survival time of glioma patients. Next, luciferase reporter indicated that CREB1 could bind directly to FOXD2-AS1 promoter region and activate its transcription. Functional investigations revealed that knockdown of FOXD2-AS1 significantly suppressed glioma cells proliferation, migration, invasion and EMT, and promoted apoptosis. Mechanistically, our results showed that FOXD2-AS1 may act as an endogenous sponge by competing for miR-185, thereby regulating the targets of this miRNA. Taken together, our data firstly demonstrated that CREB1-induced FOXD2-AS1 contributed to glioma progression by upregulating AKT1 via competitively binding to miR-185, providing a novel strategy for targeting FOXD2-AS1 as a potential biomarker and a therapeutic target in glioma patients.

Forced FoxO1:S249V expression suppressed glioma cell proliferation through G2/M cell cycle arrests and increased apoptosis

ABSTRACTObjective: Forkhead box O1 (FoxO1) plays a crucial role in the development of many tumors. Cyclin D kinase (CDK) 1 could influence the nuclear export and activity of FoxO1 through phosphorylation of serine (S)249. However, the effects of S249 phosphorylation in the development of glioma remain unclear. The aim of the present study is to assess the function of FoxO1:S249V mutant, which was converted S249 phosphorylation site into valine (V) residues in the glioma development.Methods: FoxO1-knockdown U251 glioma cells (U251-KD cells) were established by infection of retrovirus particles with FoxO1 siRNA and FoxO1 restored cells (FoxO1:S249V) were obtained by re-introduction of FoxO1:S249V cDNA. We detected mRNA expression by real-time PCR, and cell cycle arrest and apoptosis by flow cytometric assay, and cell proliferation by BrdU assay and CCK-8 assay. The protective effects of FoxO1:S249V were detected by the xenograft tumor formation assay.Results: The FoxO1 mRNA expression was significantly decreased in the glioma specimens (n = 24). The U251-KD cells showed downregulation of p27 and Bim, while the phosphorylation of CDK1 was upregulated. FoxO1:S249V cells inhibited the phosphorylation of S249, and induced G2/M cell cycle arrest, following reduced cell growth and increased apoptosis. Moreover, FoxO1:S249V expression effectively inhibits the glioma growth.Conclusion: Our findings suggest that the forced FoxO1:S249V suppressed the cell growth through G2/M cell cycle arrests and increased apoptosis in glioma.

MiR-103/miR-195/miR-15b Regulate SALL4 and Inhibit Proliferation and Migration in Glioma.

Glioma is the common highly malignant primary brain tumor. However, the molecular pathways that result in the pathogenesis of glioma remain elusive. In this study, we found that microRNA-103 (miR-103), microRNA-195 (miR-195), or microRNA-15b (miR-15b), which all have the same 5′ “seed” miRNA portion and share common binding sites in the SALL4 3′-untranslated region (UTR), were downregulated in glioma tissues and cell lines. These miRNAs suppressed glioma cell proliferation, migration, and invasion, induced cell apoptosis, and decreased the level of the SALL4 protein, but not that of SALL4 mRNA, which was identified as a direct target of all three miRNAs. The caspase-3/7 activity expression in U251 cells overexpressing these miRNAs was rescued during SALL4 upregulation. An obvious inverse correlation was observed between SALL4 and miR-103 or miR-195 expression levels in clinical glioma samples. Moreover, enforced expression of SALL4 stimulated cell proliferation, migration, and invasion. In conclusion, these data suggest that miR-103, miR-195, and miR-15b post-transcriptionally downregulated the expression of SALL4 and suppressed glioma cell growth, migration, and invasion, and increased cell apoptosis. These results provide a potential therapeutic target that may downregulate SALL4 in glioma.

Circular RNA hsa_circ_0074362 Promotes Glioma Cell Proliferation, Migration, and Invasion by Attenuating the Inhibition of miR-1236-3p on HOXB7 Expression.

As a novel type of noncoding RNAs, circular RNAs (circRNAs) have been acknowledged as pivot effectors in multiple physiological and pathological processes, including cancer. Although an increasing number of circRNAs are gradually discovered, their function and mechanism in tumorigenesis remain largely unknown. In this study, we identified hsa_circ_0074362 as an oncogene in glioma. We examined hsa_circ_0074362 expression in glioma tissues and cell lines by qRT-PCR and investigated its functions by using CCK8 and transwell assays. Luciferase reporter assays were conducted to confirm the interaction between miR-1236-3p and hsa_circ_0074362 or HOXB7. Results demonstrated that hsa_circ_0074362 was significantly upregulated in glioma tissues compared with normal tissues, and hsa_circ_0074362 overexpression was correlated with clinical severity and poor prognosis in patients with glioma. Moreover, hsa_circ_0074362 knockdown remarkably suppressed glioma cell proliferation, migration, and invasion. Luciferase reporter assay indicated that hsa_circ_0074362 acted as a sponge of miR-1236-3p to promote HOXB7 expression. Thus, hsa_circ_0074362 played a crucial role in glioma progression by regulating the miR-1236-3p/HOXB7 pathway.