Promotes Glioma Cell Proliferation Research Articles

MiR-188 Inhibits Glioma Cell Proliferation and Cell Cycle Progression Through Targeting β-Catenin.

MicroRNAs (miRNAs) play important roles in several human cancers. Although miR-188 has been suggested to function as a tumor repressor in cancers, its precise role in glioma and the molecular mechanism remain unknown. In the present study, we investigated the effect of miR-188 on glioma and explored its relevant mechanisms. We found that the expression of miR-188 is dramatically downregulated in glioma tissues and cell lines. Subsequent investigation revealed that miR-188 expression was inversely correlated with β-catenin expression in glioma tissue samples. Using a luciferase reporter assay, β-catenin was determined to be a direct target of miR-188. Overexpression of miR-188 reduced β-catenin expression at both the mRNA and protein levels, and inhibition of miR-188 increased β-catenin expression. Moreover, we found that overexpression of miR-188 suppressed glioma cell proliferation and cell cycle G1–S transition, whereas inhibition of miR-188 promoted glioma cell proliferation. Importantly, silencing β-catenin recapitulated the cellular and molecular effects seen upon miR-188 overexpression, which included inhibiting glioma cell proliferation and G1–S transition. Taken together, our results demonstrated that miR-188 inhibits glioma cell proliferation by targeting β-catenin, representing an effective therapeutic strategy for glioma.

Long non-coding RNA ZEB1-AS1 promotes glioma cell proliferation, migration and invasion through regulating miR-577.

Long non-coding RNA ZEB1-AS1 (ZEB1-AS1) was reported to be implicated and aberrantly expressed in multiple cancers. However, the potential mechanism and clinical significance of ZEB1-AS1 in the carcinogenesis of glioma remain unclear. RT-PCR was performed to determine the expression of ZEB1-AS1 in glioma tissues and cell lines. The association between ZEB1-AS1 expression and clinical features and prognosis were statistically analyzed. MTT and transwell assays were used to test the proliferation, invasion, and migration of glioma cells. Luciferase report assay was used to detect the correlation between ZEB1-AS1 and miR-577 in glioma. Compared with normal brain tissues and cells, ZEB1-AS1 in glioma tissues and cell lines was shown to be expressed at high levels. Clinical association analysis indicated that ZEB1-AS1 expression was closely associated with tumor size (p = 0.014), KPS (p = 0.004) and WHO grade (p = 0.001). In addition, it was observed that high expression level of ZEB1-AS1 was remarkably associated with overall survival and could be an independent prognostic indicator of glioma using univariate and multivariate analysis. Functional experiments demonstrated that down-regulation of ZEB1-AS1 suppressed the proliferation, invasion, and migration of glioma cell in vitro. In the mechanism, we found that ZEB1-AS1 acted as a competing endogenous RNA to sponge miR-577. Moreover, miR-577 could reverse the tumor-promotive role of ZEB1-AS1 on glioma cells. Our findings demonstrated that ZEB1-AS1 might play an oncogenic role in glioma and was a poor prognostic factor. The ZEB1-AS1/miR-577 axis might be a potential target for the development of effective glioma therapy.

PHAP1 promotes glioma cell proliferation by regulating the Akt/p27/stathmin pathway.

PHAP1 (Putative HLA‐DR‐associated protein 1), also termed acidic leucine‐rich nuclear phosphoprotein 32A (ANP32A), Phosphoprotein 32 (pp32) or protein phosphatase 2A inhibitor (I1PP2A), is a multifunctional protein aberrantly expressed in multiple types of human cancers. However, its expression pattern and clinical relevance in human glioma remain unknown. In this study, Western blotting and immunohistochemistry analysis demonstrated PHAP1 protein was highly expressed in glioma patients, especially in those with high‐grade disease. Publicly available data also revealed high levels of PHAP1 were associated with poor prognosis in glioma patients. The functional studies showed that knock‐down of PHAP1 suppressed the proliferation of glioma cells, while overexpression of PHAP1 facilitated it. The iTRAQ proteomic analysis suggested that stathmin might be a potential downstream target of PHAP1. Consistently, PHAP1 knock‐down significantly decreased the expression of stathmin, while overexpression of PHAP1 increased it. Also, the upstream negative regulator, p27, expression levels increased upon PHAP1 knock‐down and decreased when PHAP1 was overexpressed. As a result, the phosphorylated Akt (S473), an upstream regulator of p27, expression levels decreased upon silencing of PHAP1, but elevated after PHAP1 overexpression. Importantly, we demonstrate the p27 down‐regulation, stathmin up‐regulation and cell proliferation acceleration induced by PHAP1 overexpression were dependent on Akt activation. In conclusion, the above results suggest that PHAP1 expression is elevated in glioma patients, which may accelerate the proliferation of glioma cells by regulating the Akt/p27/stathmin pathway.

Long non-coding RNA ENST01108 promotes carcinogenesis of glioma by acting as a molecular sponge to modulate miR-489

Gliomas are the most common primary malignant tumor in the adult central nervous system with poor prognosis. Exploring novel biomarkers and elucidating underlying molecular mechanisms to provide effective therapeutic methods is in an urgent need. Long noncoding RNAs (lncRNAs) is involved in various human diseases including cancer. However, studies on lncRNAs and gliomas are limited. In this study, we explored the expression patterns of lncRNAs in 4 pairs of glioma samples and adjacent normal tissues via microarray and chose the most up-regulated lncRNA ENST01108 (ENST01108) to further verify its oncogenic role in glioma. Clinical data suggest that ENST01108 is closely associated with the malignant status in glioma. In vitro experiment demonstrated that overexpression of ENST01108 promoted glioma cell proliferation, migration, invasion, EMT process and survival, while knockdown of ENST01108 has an opposite effect, indicating that ENST01108 serves as an oncogenic property in glioma carcinogenesis. Further, we identified miR-489 as a direct target of ENST01108 and ENST01108 negatively regulate miR-489 by act as a sponge. SIK1 is verified as the direct target of miR-489 and it is negatively regulated by miR-489. ENST01108 also positively regulate SIKI and it promotes SIKI expression by suppressing miR-489. Taken together, the reciprocal repression of ENST011081 and miR-489 may be served as potential targets for cancer therapeutics in glioma.

Long Noncoding RNA UCA1 Targets miR-122 to Promote Proliferation, Migration, and Invasion of Glioma Cells.

Glioma is the most common and lethal malignant intracranial tumor. Long noncoding RNAs (lncRNAs) have been identified as pivotal regulators in the tumorigenesis of glioma. However, the role of lncRNA urothelial carcinoma-associated 1 (UCA1) in glioma genesis is still unknown. The purpose of this study was to investigate the underlying function of UCA1 on glioma genesis. The results demonstrated that UCA1 was upregulated in glioma tissue and indicated a poor prognosis. UCA1 knockdown induced by si-UCA1 significantly suppressed the proliferative, migrative, and invasive activities of glioma cell lines (U87 and U251). Bioinformatics analysis and luciferase reporter assay verified the complementary binding within UCA1 and miR-122 at the 3′-UTR. Functional experiments revealed that UCA1 acted as an miR-122 “sponge” to modulate glioma cell proliferation, migration, and invasion via downregulation of miR-122. Overall, the present study demonstrated that lncRNA UCA1 acts as an endogenous sponge of miR-122 to promote glioma cell proliferation, migration, and invasion, which provides a novel insight and therapeutic target in the tumorigenesis of glioma.

Retracted: MicroRNA‐21 promotes glioma cell proliferation and inhibits senescence and apoptosis by targeting SPRY1 via the PTEN/PI3K/AKT signaling pathway

Our study aims to investigate the effect of microRNA-21 (miR-21) on the proliferation, senescence, and apoptosis of glioma cells by targeting SPRY1 via the PTEN/PI3K/AKT signaling pathway. Glioma tissues and brain tissues were collected for this study after surgical decompression for traumatic brain injury. RT-qPCR was employed to measure mRNA levels of miR-21, SPRY1, PTEN, PI3K, and AKT, and Western blotting was conducted to determine protein levels of SPRY1, PTEN, PI3K, AKT, p-AKT, Caspase-3, Caspase-9, P53, GSK3, and p-GSK3. Human glioma U87 cells were assigned into the blank, negative control (NC), miR-21 mimics, miR-21 inhibitors, siRNA-SPRY1, and miR-21 inhibitors + siRNA-SPRY1 groups, with human HEB cells serving as the normal group. Cell proliferation, cell cycle, and apoptosis were determined by MTT and flow cytometry, respectively. Compared with control group, an increased expression of miR-21, PI3K, AKT, p-AKT, P53, and p-GSK3, and a decreased expression of SPRY1, PTEN, Caspase-3, and Caspase-9 were observed in the glioma group, and no significant differences were found in the expression of GSK3. SPRY1 was verified to be the target gene of miR-21. Compared with the blank and NC groups, levels of PI3K, AKT, p-AKT, P53, and p-GSK3 increased while levels of SPRY1, PTEN, Caspase-3, and Caspase-9 decreased in the miR-21 mimics and siRNA-SPRY1 groups; the miR-21 inhibitors group reversed the tendency; furthermore, the miR-21 inhibitors group showed decreased cell proliferation but promoted apoptosis, which were opposite to the results of the miR-21 mimics and siRNA-SPRY1 groups. MicroRNA-21 might promote cell proliferation and inhibit cell senescence and apoptosis of human glioma cells by targeting SPRY1 via the PTEN/PI3K/AKT signaling pathway.

Long Intergenic Noncoding RNA 00152 Promotes Glioma Cell Proliferation and Invasion by Interacting with MiR-16

Background/Aims: Long noncoding RNAs (lncRNAs) are a novel class of protein-noncoding transcripts that are aberrantly expressed in multiple diseases including cancers. LINC00152 has been identified as an oncogene involved in many kinds of cancer; however, its expression pattern and function in human glioma remain unclear. Methods: Quantitative real-time polymerase chain reaction was carried out to measure LINC00152 expression in human glioma cell lines and tissues. CCK-8 and EdU assays were performed to assess cell proliferation, and scratch assays and Transwell assays were used to assess cell migration and invasion, respectively. Luciferase reporter assays were carried out to determine the interaction between miR-16 and LINC00152. In vivo experiments were conducted to assess tumor formation. Results: LINC00152 was found to be significantly upregulated in human glioma cell lines and clinical samples. Knockdown of LINC00152 suppressed glioma cell proliferation, migration, and invasion in vitro. In vivo assays in nude mice confirmed that LINC00152 knockdown inhibits tumor growth. Furthermore, mechanistic investigation showed that LINC00152 binds to miR-16 in a sequence-specific manner and suppresses its expression. miR-16 inhibition strongly attenuated LINC00152 knockdown–mediated suppressive effects on proliferation, migration, and invasion. Moreover, LINC00152 induced BMI1 expression by sponging miR-16; this effect further promoted glioma cell proliferation and invasion. Conclusion: We regard LINC00152 as an oncogenic lncRNA promoting glioma cell proliferation and invasion and as a potential target for human glioma treatment.

Prosaposin Promotes the Proliferation and Tumorigenesis of Glioma Through Toll-Like Receptor 4 (TLR)-Mediated NF-Κb Signaling Pathway

Prosaposin (PSAP) is a conserved glycoprotein, which is found to express in brain, acting as neurotrophic factor. Recent studies have demonstrated that overexpression of PSAP is related to the occurrence and development of prostate cancer and breast cancer. However, there is no research about the role of PSAP in glioma. Our study firstly found that PSAP was highly expressed and secreted in clinical glioma specimens, glioma stem cells, and glioma cell lines. It was associated with poor prognosis. We found that PSAP significantly promoted the proliferation of glioma stem cells and cell lines. Moreover, PSAP promoted tumorigenesis in subcutaneous and orthotopic models of this disease. Furthermore, GSEA and KEGG analysis predicted that PSAP acts through the TLR4 and NF-κB signaling pathways, which was confirmed by western blot, immunoprecipitation, immunofluorescence, and use of the TLR4-specific inhibitor TAK-242. The findings of this study suggest that PSAP can promote glioma cell proliferation via the TLR4/NF-κB signaling pathway and may be an important target for glioma treatment. Funding: This work was funded by Chinese National Foundation of National Sciences (Nos. 81101917, 81270036, 81201802, 81673025), Program for Liaoning Excellent Talents in University (No. LR2014023), and Liaoning Province Natural Science Foundation (Nos. 20170541022, 20172250290). Declarations of Interests: The authors have declared that no conflict of interest exists. Ethics Approval Statement: This study was approved by the ethics committee of the First Affiliated Hospital of China Medical University and written informed consent was obtained from each patient.

Golgi Phosphoprotein 3 Promotes Wls Recycling and Wnt Secretion in Glioma Progression

Background/Aims: Golgi phosphoprotein 3 (GOLPH3) plays pro-malignancy roles in several types of cancer. However, the molecular mechanism underlying GOLPH3 promoting tumor progression remains poorly understood. Methods: The expression of GOLPH3 and Wntless (Wls) in glioma tissues was examined by western blotting and immunohistochemistry. EdU incorporation assay and colony formation assay was used to examine the cell growth ability. The effect of GOLPH3 on Wls recycling, Wnt secretion and β-catenin activity was detected using western blotting, immunofluorescence, RT-PCR, ELISA or luciferase assay. Results: The protein levels of GOLPH3 and Wls were upregulated and positively correlated with each other in human glioma tissues. The promoting effect of GOLPH3 on glioma cell proliferation was partially mediated by Wls. In addition, GOLPH3 interacted with Wls and GOLPH3 down-regulation drove Wls into lysosome for degradation, inhibiting its recycling to golgi and the plasma membrane. Importantly, GOLPH3 down-regulation inhibited Wnt2b secretion and decreased β-catenin level and transcription activity. Conclusions: This study provides a brand new evidence that GOLPH3 promotes glioma cell proliferation by facilitating Wls recycling and Wnt/β-catenin signaling. Our findings suggest a rationale for targeting the GOLPH3-Wls-Wnt axis as a promising therapeutic approach for glioblastoma.

MicroRNA-29a-3p Downregulation Causes Gab1 Upregulation to Promote Glioma Cell Proliferation

Background/Aims: Glioma causes significant human mortalities annually. Molecularly-targeted therapy is a focus of glioma research. Methods: Grb2-associated binding 1 (Gab1) expression and microRNA-29a-3p (“miR-29a-3p”) expression in human glioma cells and tissues were tested by Western blotting assay and qRT-PCR assay. shRNA/siRNA strategy was applied to silence Gab1 in human glioma cells. miR-29a or anti-sense miR-29a construct was transfected to human glioma cells. Cell proliferation was tested by BrdU ELISA assay and cell counting assay. Results: We show that expression of Gab1 was significantly elevated in human glioma tissues and cells, which correlated with downregulation of its putative microRNA: miR-29a-3p. In A172 glioma cells and primary human glioma cells, Gab1 shRNA/siRNA inhibited Akt-Erk activation and cell proliferation. Forced-expression of miR-29a-3p downregulated Gab1, inhibiting glioma cell proliferation, whereas miR-29a-3p was in-effective on cell proliferation in Gab1-silenced A172 cells. Furthermore, introduction of a 3’-untranslated region (3’-UTR) mutant Gab1 (UTR-G160A) blocked miR-29a-3p-induced inhibition on Akt signaling and A172 cell proliferation. Conclusions: miR-29a-3p downregulation leads to Gab1 upregulation to promote glioma cell proliferation.

Silencing NUDT21 Attenuates the Mesenchymal Identity of Glioblastoma Cells via the NF-κB Pathway.

The proneural (PN) and mesenchymal (MES) subtypes of glioblastoma multiforme (GBM) are robust and generally consistent with classification schemes. GBMs in the MES subclass are predominantly primary tumors that, compared to PN tumors, exhibit a worse prognosis; thus, understanding the mechanism of MES differentiation may be of great benefit for the treatment of GBM. Nuclear factor kappa B (NF-κB) signaling is critically important in GBM, and activation of NF-κB could induce MES transdifferentiation in GBM, which warrants additional research. NUDT21 is a newly discovered tumor-associated gene according to our current research. The exact roles of NUDT21 in cancer incidence have not been elucidated. Here, we report that NUDT21 expression was upregulated in human glioma tissues and that NUDT21 promoted glioma cell proliferation, likely through the NF-κB signaling pathway. Gene set enrichment analysis, western blotting, and quantitative real-time reverse transcription polymerase chain reaction confirmed that NF-κB inhibitor zeta (NFKBIZ) was a downstream target affected by NUDT21 and that the MES identity genes in glioblastoma cells, CHI3L1 and FN1, were also differentially regulated. Our results suggest that NUDT21 is an upstream regulator of the NF-κB pathway and a potential molecular target for the MES subtype of GBM.

MiR‑218 inhibits the proliferation of human glioma cells through downregulation of Yin Yang 1.

Malignant glioma is the most common cancer type of the nervous system and the mechanisms driving the occurrence and development remain unclear, preventing effective treatment of this disease. Therefore, novel and efficient therapies for glioma are required. MicroRNAs (miRNAs) are small non‑coding RNAs that act as oncogenes or tumor suppressors in human cancer. In the present study, it was confirmed that Yin Yang‑1 (YY1), a transcription factor that is part of the polycomb group protein (PcG) family, is a direct target of miR‑218 in human glioma cells. It was demonstrated that YY1 promoted glioma cell proliferation and miR‑218 could inhibit glioma cell proliferation by targeting YY1, and indirectly reduced the degradation of p53. Together the results indicate that miR‑218 functions as a tumor suppressor in human glioma and suggest that overexpression of miR‑218 may be a potential strategy for the treatment of human glioma in the future.

Long Noncoding RNA MEG3 Suppresses Glioma Cell Proliferation, Migration, and Invasion by Acting as a Competing Endogenous RNA of miR-19a.

Glioma, with varying malignancy grades and histological subtypes, is the most common primary brain tumor in adults. Long noncoding RNAs (lncRNAs) are non-protein-coding transcripts and have been proven to play an important role in tumorigenesis. Our study aims to elucidate the combined effect of lncRNA maternally expressed gene 3 (MEG3) and microRNA-19a (miR-19a) in human glioma U87 and U251 cell lines. Real-time PCR revealed that MEG3 was downregulated and miR-19a was upregulated in malignant glioma tissues and cell lines. Bioinformatics analyses (TargetScan, miRanda, and starBase V2.0) showed that phosphatase and tensin homolog (PTEN) is a target of miR-19a with complementary binding sites in the 3′-UTR. As expected, luciferase results verified the putative target site and also revealed the complementary binding between miR-19a and MEG3. miR-19a represses the expression of PTEN and promotes glioma cell proliferation, migration, and invasion. However, MEG3 could directly bind to miR-19a and effectively act as a competing endogenous RNA (ceRNA) for miR-19a to suppress tumorigenesis. Our study is the first to demonstrate that lncRNA MEG3 suppresses glioma cell proliferation, migration, and invasion by acting as a ceRNA of miR-19a, which provides a novel insight about the pathogenesis of glioma.

Retinol dehydrogenase-10 promotes development and progression of human glioma via the TWEAK-NF-κB axis.

Retinol dehydrogenase-10 (RDH10) is a member of the short-chain dehydrogenase/reductase family, which plays an important role in retinoic acid (RA) synthesis. Here, we show that RDH10 is highly expressed in human gliomas, and its expression correlates with tumor grade and patient survival times. In vitro, lentivirus-mediated shRNA knockdown of RDH10 suppressed glioma cell proliferation, survival, and invasiveness and cell cycle progression. In vivo, RDH10 knockdown reduced glioma growth in nude mice. Microarray analysis revealed that RDH10 silencing reduces expression of TNFRSF12A (Fn14), TNFSF12 (TWEAK), TRAF3, IKBKB (IKK-β), and BMPR2, while it increases expression of TRAF1, NFKBIA (IκBα), NFKBIE (IκBε), and TNFAIP3. This suggests that RDH10 promotes glioma cell proliferation and survival by regulating the TWEAK-NF-κB axis, and that it could potentially serve as a novel target for human glioma treatment.

MiRNA-155 promotes proliferation by targeting caudal-type homeobox 1 (CDX1) in glioma cells

MicroRNAs (miRNAs) play important roles in the tumorigenesis of glioma. Recent studies showed that miR-155 expression was increased in types of cancer, including glioma. However, the underlying mechanism of miR-155 on glioma is still unclear. In the present study, expression of miR-155 and caudal-type homeobox 1 (CDX1) was determined in glioma tissues by qRT-PCR, and the regulatory axis was further studied in glioma cells. We showed that miR-155 expression was significantly increased in glioma tissues while CDX1 expression was decreased. Correlation analysis revealed that miR-155 was negatively correlated with CDX1 expression in glioma tissues. Moreover, Kaplan–Meier analysis indicated that patients with high miR-155 expression had a poor overall survival. In addition, our results showed that the translation of CDX1 expression could be suppressed by miR-155 mimics. And miR-155 mimics promoted glioma cell proliferation could be reversed by CDX1 overexpression. In vivo assay, we showed that miR-155 overexpression promoted the progress of tumor formation. Therefore, we suggested that miR-155 might promote glioma cell growth partially by targeting CDX1, which provided a novel therapeutic strategy for glioma patients.

MicroRNA-675 promotes glioma cell proliferation and motility by negatively regulating retinoblastoma 1

Previous studies indicated that microRNA (miR)-675 and its precursor lncRNA H19 were both overexpressed in glioma tissues, and H19 might play an oncogenic role. To investigate the involvement of miR-675 in gliomas and its underlying mechanisms, we here collected candidate target genes of miR-675-5p from miRTarBase (http://mirtarbase.mbc.nctu.edu.tw/, Release 6.0), which contains the experimentally validated microRNA-target interactions. Then, regulatory effects of miR-675 on its target genes were validated using clinical samples and glioma cell lines. Involvement of the miR-675-target axis deregulation in cell proliferation, migration and invasion of glioma was demonstrated by both gain- and loss-of-function experiments. As a result, retinoblastoma 1 (RB1) was identified as a candidate target gene of miR-675-5p. Expression levels of miR-675-5p in glioma tissues and cells were negatively correlated with RB1 expression at both mRNA and protein levels. Importantly, deregulation of the miR-675-5p-RB1 axis was significantly associated with advanced World Health Organization (WHO) grade and low Karnofsky performance score (KPS) score of glioma patients. Luciferase reporter assay verified that RB1 was a direct target gene of miR-675 in glioma cells. Functionally, miR-675 promoted glioma cell proliferation, migration and invasion. Notably, simulation of RB1 antagonized the effects induced by miR-675 up-regulation in glioma cells. In conclusion, our data suggest that miR-675 may be a key negative regulator of RB1 and the imbalance of the miR-675-RB1 axis may be clinically associated with aggressive progression of glioma patients. In addition, miR-675 may act as an oncogenic miRNA in glioma cells via regulating its target gene RB1.

MiR‑146b‑5p suppresses glioblastoma cell resistance to temozolomide through targeting TRAF6.

Temozolomide (TMZ), as a kind of alkylating agent, is widely utilized for the treatment of glioblastoma(GBM). However, temozolomide resistance (TR) often develops quickly and results in tumor recurrence and poor outcome. Recent advances have demonstrated that miRNAs exert critical roles in chemoresistance. Downregulation of miR‑146b‑5p promotes glioma cell proliferation, reduces apoptosis, and correlates with poor survival of patients. Nonetheless, the function of miR‑146b‑5p in temozolomide resistance remains unclear. In the present study, we successfully generated U87 and U251‑TR cells, and found that miR‑146b‑5p was downregulated in TRcells. Overexpression of miR‑146b‑5p restored sensitivity of U87/U251‑TR cells to TMZ by targeting tumor necrosis factor receptor-associated factor6 (TRAF6). The levels of TRAF6 were inversely related to miR‑146b‑5p levels, and overexpression of TRAF6 in miR‑146b‑5p‑OE cells enhanced the resistance against TMZ. Moreover, temozolomide-resistant GBM cells had a higher level of phosphorylated protein kinaseB (AKT) and P65. Overexpression of miR‑146b‑5p or TRAF6 knockdown significantly decreased the level of p‑AKT and p‑p65. Collectively, our data demonstrated that miR‑146b‑5p, as a tumor suppressor, mediated temozolomide resistance in GBM cells through negatively regulating TRAF6 expression, indicating that miR‑146b‑5p and its targeted genes would be potential therapeutic targets for glioma therapy.

Long non-coding RNA MEG3 promotes the proliferation of glioma cells through targeting Wnt/β-catenin signal pathway.

Glioma has been identified as one of the most aggressive primary tumors. Long non-coding RNAs (lncRNAs), with length larger than 200 bp, have drawn increasing attention to their abnormal expression and regulation function in carcinogenesis. However, the role of lncRNAs in glioma remains largely unknown. Maternally expressed gene 3 (MEG3), also known as gene-trap locus 2 (GTL2), is an imprinted gene, and is encoded by the MEG3 transcript of the DLK1/MEG3 locus on human chromosome, or Meg3 on mouse chromosome. In this study, we found that lncRNA MEG3 was significantly downregulated in malignant glioma tissues and cell lines. The employment of the loss-of and gain-of functions assays presented that MEG3 suppressed glioma cells proliferation and induced cell-cycle arrest. Furthermore, our findings showed that highly expressed MEG3 could weaken Wnt/β-catenin signaling in glioma. Collectively, our findings revealed that downregulated lncRNA MEG3 could promote glioma cell proliferation through targeting Wnt/β-catenin signaling, which mainly influenced cell cycle.

Silencing Pre-B-cell leukemia homeobox 3 decreases the proliferation of human glioma cells in vitro and in vivo.

Among primary brain tumors, gliomas are the most common and most aggressive, with a poor prognosis and limited treatment options. Thus, it is essential to determine the mechanisms involved in glioma development to develop effective therapies for glioma patients. Pre-B-cell leukemia homeobox 3 (PBX3), a critical member of the PBX family, is frequently overexpressed in multiple human malignancies. However, the expression patterns and biological functions, as well as the involved molecular functions of PBX3 in human gliomas remain largely unknown. In this study, we demonstrate that PBX3 expression is increased in both human glioma tissues and cell lines compared with their normal counterparts. These results suggested that PBX3 might be involved in glioma progression. Thus, the role of PBX3 in glioma cell proliferation was investigated using genetic knockdown and overexpression methods. The results showed that PBX3 knockdown inhibited glioma cell proliferation and induced apoptosis, while PBX3 overexpression significantly promoted glioma cell proliferation. Mechanistically, we found that PBX3 promoted cell proliferation by modulating cell cycle progression. A xenograft LN229 model was used to confirm that PBX3 depletion decreased tumor growth in vivo. In summary, our findings reveal that PBX3 may be a potential therapeutic target in gliomas.

PCDH8 inhibits glioma cell proliferation by negatively regulating the AKT/GSK3β/β-catenin signaling pathway.

Protocadherin-8 (PCDH8), a member of the protocadherin superfamily of proteins, is frequently lost in numerous types of cancer. However, the role that PCDH8 serves in human glioma, and the molecular mechanisms underlying this, remain unclear. Data from the present study demonstrated that the expression levels of PCDH8 mRNA and protein were significantly decreased in human glioma tissue compared with normal brain tissue. This suggested that PCDH8 is associated with the development of glioma. Thus, the role of PCDH8 in glioma cell proliferation was investigated by silencing and overexpressing PCDH8 in U251 glioma cells. Overexpression of PCDH8 significantly inhibited glioma cell proliferation, while silencing of PCDH8 using small interfering RNA promoted glioma cell proliferation. Restoration of PCDH8 decreased phosphorylated (p)-Rac-α serine/threonine-protein kinase (AKT) [Threonine (T)308/Serine (S)473] and p-glycogen synthase kinase-3β (p-GSK3β) (S9) protein expression, thereby reducing the level of β-catenin when compared with the control. By contrast, silencing of PCDH8 increased levels of p-AKT (T308/S473) and p-GSK3β (S9), thereby increasing the level of β-catenin. In conclusion, the results of the present study suggested that PCDH8 suppressed glioma cell proliferation, and that the loss of PCDH8 may stimulate the proto-oncogene Wnt/β-catenin signaling pathway and therefore promote glioma cell proliferation.