Behavior Of Human Glioma Cells Research Articles

MiR-4530 inhibits the malignant biological behaviors of human glioma cells by directly targeting RTEL1.

Human glioma is the most common primary brain tumor and is associated with high morbidity and mortality. Aberrant expressions of microRNAs (miRNAs) are involved in glioma progression. In the present study, we aimed to elucidate the roles of miR-4530 in the pathogenesis of gliomas. miR-4530 expression was examined in human glioma clinical tissues and cell lines including U251 and T98G. The target gene of miR-4530, RTEL1, was predicted with online tools and validated by luciferase reporter assay. Lentivirus infection, transfection of plasmids, and miRNA mimics were used to manipulate gene expression. Cell proliferation was determined using the CCK-8 method, and migration and invasion assays were determined with transwell experiments. Colony formation was measured by crystal violet staining, while apoptosis was determined by Annexin V/PI staining. The anti-tumor effects of miR-4530 were evaluated in nude mice xenografted using U251 cells. Our results showed that miR-4530 was significantly down-regulated in human glioma tissues and cell lines. miR-4530 over-expression inhibited the malignant behaviors of U251 and T98G cells, including reduced proliferation, diminished colony formation, migration and invasion, and increased apoptosis. Further mechanistic investigations revealed that RTEL1 is a direct functional target of miR-4530 in gliomas, and its over-expression remarkably reverses the effects of miR-4530 mimics on inhibiting these malignant behaviors. In addition, miR-4530 over-expression inhibited the growth of xenografted U251 glioma in nude mice. Therefore, miR-4530 acts as a tumor-suppressor gene and inhibits the malignant biological behaviors of human glioma cells, which is associated with directly targeting RTEL1. The miR-4530/RTEL1 axis is a potential therapeutic target for gliomas.

Researches of microRNA-200a on malignant biological behavior of human glioma cells

Objective To investigate the effect of microRNA (miRNA, miR)-200a on proliferation, apoptosis, migration and cell cycle of glioma cell line U251 and its possible mechanism. Methods miR-200a mimics (miR-200a group) and nonsense sequences (Mock group) were transfected into human glioma cell line U251 in vitro by liposome transient transfection. Blank group (Blank group) group). The expression of miR-200a was detected by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) after transfection for 48 hours. The cell proliferation ability of the three groups was detected by cell counting kit-8 (CCK-8) method. The cell migration ability was detected by scratches. Cell apoptosis and cell cycle were detected by flow cytometry The expression of ZEB1 and Cyclin D1 protein was detected by Western blotting. Results Compared with the Mock and Blank groups, the relative expression of miR-200a in miR-200a cells was significantly higher than that in the untreated group (P=0.000, 0.000). The cells of miR-200a cells were significantly different (P=0.028, 0.010). The cell migration ability of miR-200a group was significantly decreased (P=0.031, 0.030), the proportion of G0/G1 phase cells in miR-200a group was increased (P=0.011, 0.013), the proportion of S phase cells was significantly decreased (P=0.024, 0.008), and the apoptosis rate of miR-200a group was significantly lower than that of miR-200a group (P=0.001, 0.001). Western blotting showed that the expression of ZEB1 (P=0.042, 0.034) and the expression of Cyclin D1 were significantly down-regulated (P=0.020, 0.013). Conclusion Upregulation of miR-200a can promote glioma cell apoptosis, block its cell cycle progression and inhibit its migration ability, which is expected to be a new target for the treatment of glioma. Key words: Glioma; MicroRNA-200a; Apoptosis; Cell Cycle; Cell Migration

PVT1 regulates the malignant behaviors of human glioma cells by targeting miR-190a-5p and miR-488-3p

The long non-coding RNA (lncRNA) PVT1 is reported to be involved in tumorigenesis and the progression of many malignancies. However, the function of PVT1 in gliomas remains unclarified. The present study demonstrated the expression level of PVT1 using qRT-PCR. The role of PVT1 in the regulation of biological behaviors of glioma cells was investigated using CCK-8 assay, Transwell assay and flow cytometry. The possible molecular mechanisms were also elucidated. In our results, PVT1 was up-regulated in glioma specimens and cell lines. Knockdown of PVT1 impaired the malignant behaviors of glioma cells via the suppression of proliferation, migration and invasion, as well as through promotion of apoptosis. Furthermore, PVT1 was identified to affect the glioma cells via binding to miR-190a-5p and miR-488-3p, which were down-regulated and played tumor suppressor roles in glioma cells. Up-regulated miR-190a-5p or miR-488-3p partially rescued the suppressive effect induced by PVT1 knockdown. Myocyte enhancer factor 2C (MEF2C) was a direct downstream target of miR-190a-5p and miR-488-3p, which was proved to be an oncogene and involved in the PVT1 knockdown induced regulation of biological behaviors of glioma cells. Over-expression of MEF2C up-regulated JAGGED1 by increasing the promoter activity of JAGGED1. PVT1 knockdown combined with miR-190a-5p and miR-488-3p over-expression contributed to the smallest tumor volume and the longest survivals in nude mice. In conclusion, PVT1-miR-190a-5p/miR-488-3p-MEF2C-JAGGED1 axis is involved in proliferation and progression of glioma. Thus, PVT1 may become a novel target in glioma therapy.

MiR-148b-3p inhibits malignant biological behaviors of human glioma cells induced by high HOTAIR expression.

Increasing evidence suggests that long non coding (lnc)RNA and microRNA (miRNA/miR) both regulate the expression of key genes in tumorigenesis and have considerable theranostic potential. Rapid advances in bioinformatics indicate that miRNA may potentially interact with lncRNA to modulate their regulatory roles. miR-148b-3p has been reported to have a vital role in regulating tumor progression. However, the expression pattern of miR-148b-3p in glioma remains largely unknown, and interactions between miR-148b-3p and lncRNA has yet to be identified. The aim of the present study was to insight into the regulatory role of miR-148b-3p in glioma. Using online software, the HOTAIR gene was identified as a possible lncRNA target of miR-148b-3p in the present study. siRNA was used to suppress the expression of HOTAIR and reverse transcription-quantitative polymerase chain reaction was used to detect the expression of miR-148b-3p. The results confirmed that HOTAIR mRNA expression was inversely correlated with miR-148b-3p expression in A172 glioma cells. Furthermore, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to detect the viability of cells, flow cytometry was performed to test cell cycle and a matrigel invasion assay was performed to test cell invasion. The results showed that HOTAIR promotes factors associated with malignancy, including cell proliferation, cell cycle progression and invasion, whereas miR-148b-3p suppresses malignancy. Bioinformatics and luciferase reporter assays showed that miR-148b-3p modulates HOTAIR expression by directly targeting the HOTAIR gene sequence. In summary, the results indicated that miR-148b-3p inhibits malignant biological behaviors of glioma cells by directly targeting HOTAIR. The current data provide important evidence for understanding the key roles of the lncRNA miRNA functional network in glioma.

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

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

Upregulation of miR-184 Enhances the Malignant Biological Behavior of Human Glioma Cell Line A172 by Targeting FIH-1

Background: In recent years, miRNAs have been suggested to play key roles in the formation and development of human glioma. The aim of this study is to investigate the effect and mechanism of miR-184 expression on the malignant behavior of human glioma cells. Methods: The relative quantity of miR-184 was determined in human glioma cell lines, and the expression of hypoxia-inducible factor-1 alpha (HIF-1α) was explored using western blotting. The effects of miR-184 inhibition on cell viability and apoptosis were explored, and the miR-184 target gene was determined using a luciferase assay and western blotting. Flow cytometry and Hoechst staining were used to evaluate cell growth and apoptosis. Matrigel invasion and scratch assays were performed to measure the ability of cell invasion and migration. Results: miR-184 and HIF-1α protein levels were significantly upregulated in human glioma cells. Downregulation of miR-184 inhibited cell viability and increased the HEB cell apoptotic rate. Luciferase and western blot assays verified that FIH-1 was the target gene of miR-184 and negatively controlled the protein level of HIF-1α. Inhibition of HIF-1α by siRNA facilitated the apoptosis of HEB cells and suppressed A172 cell invasion and migration. Conclusion: miR-184 upregulation enhanced the malignant phenotype of human glioma cancer cells by reducing FIH-1 protein expression.

Artemether Combined with shRNA Interference of Vascular Cell Adhesion Molecule-1 Significantly Inhibited the Malignant Biological Behavior of Human Glioma Cells

Artemether is the derivative extracted from Chinese traditional herb and originally used for malaria. Artemether also has potential therapeutic effects against tumors. Vascular cell adhesion molecule-1 (VCAM-1) is an important cell surface adhesion molecule associated with malignancy of gliomas. In this work, we investigated the role and mechanism of artemether combined with shRNA interference of VCAM-1 (shRNA-VCAM-1) on the migration, invasion and apoptosis of glioma cells. U87 human glioma cells were treated with artemether at various concentrations and shRNA interfering technology was employed to silence the expression of VCAM-1. Cell viability, migration, invasiveness and apoptosis were assessed with MTT, wound healing, Transwell and Annexin V-FITC/PI staining. The expression of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9) and phosphorylated Akt (p-Akt) was checked by Western blot assay. Results showed that artemether and shRNA-VCAM-1 not only significantly inhibited the migration, invasiveness and expression of MMP-2/9 and p-Akt, but also promoted the apoptosis of U87 cells. Combined treatment of both displayed the maximum inhibitory effects on the malignant biological behavior of glioma cells. Our work revealed the potential therapeutic effects of artemether and antiVCAM-1 in the treatments of gliomas.

Inhibition of Nodal suppresses angiogenesis and growth of human gliomas

Angiogenesis is the hallmark of malignant gliomas positively correlated with the vascular endothelial growth factor (VEGF) expression. We previously reported that expression levels of Nodal, a member of transforming growth factor-β super family, correlate with the malignant invasive behavior of human glioma cells. In this study, we show that knockdown of Nodal suppresses glioma angiogenesis by inhibition of VEGF. In human primary glioma specimens, expression of Nodal positively correlates with WHO glioma tumor grades and expression of VEGF in the corresponding glioma specimens. In human U87MG glioma cells, knockdown of endogenous Nodal by RNA interference (RNAi) significantly decreases colony formation and secretion of VEGF. In vivo, cellular depletion of Nodal in U87MG inhibited brain glioma growth and prolonged the survival of mice with U87MG/shNodal glioma compared with controls. Inhibition of Nodal suppressed tumor vessel growth in U87MG gliomas. Using Nodal inhibitor (SB431542), silencing Nodal, or overexpressing Nodal in the U87MG, GBM8401, and GBM glioma cells, our further experiments revealed that Nodal-induced VEGF expression might, at least in part, mediate through the ERK1/2-HIF-1α-mediated signaling pathway. Taken together, our data revealed that alteration of Nodal expression in glioma cells resulted in changes to VEGF secretion, and subsequent colony formation, in vivo tumor growth, and angiogenesis, all of which are consistent with the regulation of VEGF through the ERK1/2-HIF-1α-mediated signaling, suggesting that Nodal may serve as a potential therapeutic target for the treatment of human gliomas.

Role of Rap1B and Tumor Suppressor PTEN in the Negative Regulation of Lysophosphatidic Acid—induced Migration by Isoproterenol in Glioma Cells

The clarification of mechanisms that negatively regulate the invasive behavior of human glioma cells is of great importance in order to find new methods of treatment. In this study, we have focused on the negative regulation of lysophosphatidic acid (LPA)-induced migration in glioma cells. Using small interference RNA and dominant-negative gene strategies in addition to pharmacological tools, we found that isoproterenol (ISO) and sphingosine-1-phosphate (S1P) negatively but differently regulate the LPA-induced migration. ISO-induced suppression of the migration of glioma cells occurs via beta(2)-adrenergic receptor/cAMP/Epac/Rap1B/inhibition of Rac, whereas S1P has been shown to suppress the migration of the cells through S1P(2) receptor/Rho-mediated down-regulation of Rac1. The expression of tumor suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is required for the inhibitory ISO-induced and Rap1B-mediated actions on the migration, Rac1 activation, and Akt activation in response to LPA. Thus, the PTEN-mediated down-regulation of phosphatidylinositol 3-kinase activity may be involved in the regulation of Rap1B-dependent inhibition of Rac1 activity. These findings suggest that there are at least two distinct inhibitory pathways, which are mediated by the S1P(2) receptor and beta(2)-adrenergic receptor, to control the migratory, hence invasive, behavior of glioma cells.

Adenovirus-mediated over-expression of p21Waf-1 differentially affects the proliferation, telomerase activity, and expression of glial fibrillary acidic protein in human glioma cells.

Over-expression of p21Waf-1 was performed in 5 human glioma cell lines (U251MG, U87MG, T98G, NMC-G1, and KALS-1). p53 gene status was examined by PCR-SSCP and direct sequence method. The endogenous p21Waf-1 expression was evaluated by RT-PCR. Adenovirus-mediated over-expression of p21Waf-1 inhibited the proliferation of human glioma cells expressing wild-type p53 (U87MG, NMC-G1, KALS-1) irrespective of endogenous p21Waf-1 expression. Telomerase activity was also reduced in these cells. In U87MG, GFAP expression was stimulated by the transfection with p21Waf-1, but was reduced in NMC-G1. Over-expression of p21Waf-1 thus affects the cellular behavior of human glioma cells in a cell-type specific manner.

Migratory patterns of lac‐z transfected human glioma cells in the rat brain

Malignant brain tumors are characterized by extensive tumor-cell infiltration into the normal brain tissue. The present work describes the migratory behavior of human glioma cells transplanted into the adult rat brain with the aim of exploiting the extent of active cell migration and passive cell displacement within the central nervous system. To detect every transplanted tumor cell, a stably bacterial beta-galactosidase (lac-z) transfected human glioma cell line was used. To distinguish between an active cell migration process and passive cell displacement, rat brains were also implanted with inert fluorescent polystyrene microspheres and the distribution of tumor cells and microspheres was studied 1 hr and 3 days after implantation. One hour after implantation the tumor cells were strictly localized at the implantation site. However, 3 days after implantation, both tumor cells and microspheres showed an extensive distribution within the brain. Confirming earlier neuropathological and experimental studies, it is shown that the lac-z-transfected glioma cells had the capacity to move within the Virchow-Robin and subarachnoid spaces. However, since fluorescent microspheres were also found in these areas, this spread of tumor cells may be primarily mediated by the extensive cerebrospinal fluid flow that exists within the brain. Three days after implantation, the glioma cells also showed an active migration over the corpus callosum. In comparison, the fluorescent microspheres showed only limited spread along the callosal body. It is concluded that the bacterial lac-z gene can be stably transfected into human glioma cells and, since every tumor cell can be visualized within the brain, this model provides a tool for studying the mechanisms behind tumor-cell invasion of the brain.