Tumorigenesis Of Glioblastoma Cells Research Articles

Cyclohexene oxide CA, a derivative of zeylenone, exhibits anti-cancer activity in glioblastoma by inducing G0/G1 phase arrest through interference with EZH2.

Introduction: Due to its highly aggressiveness and malignancy, glioblastoma (GBM) urgently requires a safe and effective treatment strategy. Zeylenone, a natural polyoxygenated cyclohexenes compound isolated from Uvaria grandiflora, has exhibited potential biological activities in various human diseases, including tumors. Methods: We designed and synthesized a series of (+)-Zeylenone analogues and evaluated their anti-GBM roles through structural-activity analysis. Cell Counting Kit-8, TUNEL, transwell and flow cytometry were employed for investigating the anticancer effects of CA on GBM cells. Western blotting, molecular docking, qRT-PCR and ChIP assays were performed to reveal the underlying mechanisms by which CA regulates the GBM cell cycle. The nude mouse xenograft model, HE staining, immunohistochemistry and was used to evaluate the anticancer effect of CA in vivo. Results: We identified CA ((1R, 2R, 3S)-3-p-fluorobenzoyl-zeylenone) as having the lowest IC50 value in GBM cells. CA treatment significantly inhibited the malignant behaviors of GBM cells and induced G0/G1 phase arrest in vitro. Furthermore, we validated the molecular mechanism by which CA interferes with EZH2, attenuating the down-regulation of cyclin-dependent kinase inhibitors p27 and p16 by the PRC2 complex. By establishing orthotopic nude mice models, we further validated the inhibitory role of CA on tumorigenesis of GBM cells in vivo and its potential values to synergistically potentiate the anti-tumor effects of EZH2 inhibitors. Conclusion: Overall, this paper elucidated the anti-GBM effects and potential mechanisms of CA, and may provide a therapeutic drug candidate for GBM treatment.

Cooperatively inhibition effect of miR-143-5p and miR-145-5p in tumorigenesis of glioblastoma cells through modulating AKT signaling pathway

Introduction: As the most common aggressive primary brain tumor, glioblastoma is inevitably a recurrent malignancy whose patients’ prognosis is poor. miR-143 and miR-145, as tumor suppressor miRNAs, are downregulated through tumorigenesis of multiple human cancers, including glioblastoma. These two miRNAs regulate numerous cellular processes, such as proliferation and migration. This research was intended to explore the simultaneous replacement effect of miR-143, and miR-145 on in vitro tumorgenicity of U87 glioblastoma cells. Methods: U87 cells were cultured, and transfected with miR-143-5p and miR-145-5p. Afterward, the changes in cell viability, and apoptosis induction were determined by MTT assay and Annexin V/PI staining. The accumulation of cells at the cell cycle phases was assessed using the flow cytometry. Wound healing and colony formation assays were performed to study cell migration. qRT-PCR and western blot techniques were utilized to quantify gene expression levels. Results: Our results showed that miR-143-5p and 145-5p exogenous upregulation cooperatively diminished cell viability, and enhanced U-87 cell apoptosis by modulating Caspase-3/8/9, Bax, and Bcl-2 protein expression. The combination therapy increased accumulation of cells at the sub-G1 phase by modulating CDK1, Cyclin D1, and P53 protein expression. miR-143/145-5p significantly decreased cell migration, and reduced colony formation ability by the downregulation of c-Myc and CD44 gene expression. Furthermore, the results showed the combination therapy of these miRNAs could remarkably downregulate phosphorylated-AKT expression levels. Conclusion: In conclusion, miR-143 and miR-145 were indicated to show cooperative anti- cancer effects on glioblastoma cells via modulating AKT signaling as a new therapeutic approach.

MOXD1 knockdown suppresses the proliferation and tumor growth of glioblastoma cells via ER stress-inducing apoptosis

Oxygenase-catalyzed reduction and activation of oxygen molecules and the incorporation of oxygen atoms into organic molecules are undoubtedly necessary in the process of tumor development, and it is also one of the research hotspots in recent years. MOXD1 belongs to the copper-dependent monooxygenase family. The expression of MOXD1 is one of the characteristics of early tumor development. However, it is not understandable that the biological function and molecular mechanism of MOXD1 in Glioblastoma (GBM). In this study, high MOXD1 expression is strongly associated with poor survival of the patient with GBM. Moreover. MOXD1 knockdown can inhibit cell viability, proliferation, migration, invasion, and tumorigenesis of GBM cells. This is also proven for the first time that MOXD1 can bind to β3GnT2 and affect the glycosylation modification of some proteins. In addition, knockdown of MOXD1 induces endoplasmic reticulum (ER) stress and triggers the ER–mitochondrial apoptosis pathway. Taken together, these results reveal that MOXD1 is involved in the occurrence and development of GBM, and also provide a new strategy for targeted therapy.

LncRNA HOXA-AS2 promotes glioblastoma carcinogenesis by targeting miR-885-5p/RBBP4 axis

BackgroundLncRNA HOXA-AS2 has been found in the literature to deteriorate glioblastoma. However, its regulatory mechanism is yet to be fully investigated. Our study focused chiefly on the interaction and role of the HOXA-AS2/miR-885-5p/RBBP4 axis in the development of glioblastoma.MethodsqRT-PCR analysis was performed to detect the expression of lncRNA, miRNA and mRNA in glioblastoma tissues and cells. Dual-luciferase assay, RIP assay and RNA pull-down assay were later carried out to reveal the interactions among HOXA-AS2, miR-885-5p and RBBP4. After that, CCK-8 assay, BrdU assay, nude mice xenografting assay, western blot assay, and flow cytometry were carried out to analyze the effect of the HOXA-AS2/miR-885-5p/RBBP4 axis on glioblastoma samples.ResultsHOXA-AS2 and RBBP4 were found to be overexpressed in glioblastoma. Experimental results showed that HOXA-AS2 and RBBP4 contributed to the tumorigenesis of glioblastoma cells. However, miR-885-5p was observed to be downregulated in glioblastoma. Findings also indicated that HOXA-AS2 could negatively regulate miR-885-5p, thereby enhancing RBBP4 expression.ConclusionOverall, HOXA-AS2 promoted the tumorigenesis of glioblastoma by targeting and regulating miR-885-5p to induce the expression of RBBP4.

Histone demethylase KDM4C controls tumorigenesis of glioblastoma by epigenetically regulating p53 and c-Myc

Glioblastoma is the most lethal brain tumor and its pathogenesis remains incompletely understood. KDM4C is a histone H3K9 demethylase that contributes to epigenetic regulation of both oncogene and tumor suppressor genes and is often overexpressed in human tumors, including glioblastoma. However, KDM4C’s roles in glioblastoma and the underlying molecular mechanisms remain unclear. Here, we show that KDM4C knockdown significantly represses proliferation and tumorigenesis of glioblastoma cells in vitro and in vivo that are rescued by overexpressing wild-type KDM4C but not a catalytic dead mutant. KDM4C protein expression is upregulated in glioblastoma, and its expression correlates with c-Myc expression. KDM4C also binds to the c-Myc promoter and induces c-Myc expression. Importantly, KDM4C suppresses the pro-apoptotic functions of p53 by demethylating p53K372me1, which is pivotal for the stability of chromatin-bound p53. Conversely, depletion or inhibition of KDM4C promotes p53 target gene expression and induces apoptosis in glioblastoma. KDM4C may serve as an oncogene through the dual functions of inactivation of p53 and activation of c-Myc in glioblastoma. Our study demonstrates KDM4C inhibition as a promising therapeutic strategy for targeting glioblastoma.

Wnt-Induced Stabilization of KDM4C Is Required for Wnt/β-Catenin Target Gene Expression and Glioblastoma Tumorigenesis.

Wnt/β-catenin signaling activates the transcription of target genes to regulate stem cells and cancer development. However, the contribution of epigenetic regulation to this process is unknown. Here, we report that Wnt activation stabilizes the epigenetic regulator KDM4C that promotes tumorigenesis and survival of human glioblastoma cells by epigenetically activating the transcription of Wnt target genes. KDM4C protein expression was upregulated in human glioblastomas, and its expression directly correlated with Wnt activity and Wnt target gene expression. KDM4C was essential for Wnt-induced gene expression and tumorigenesis of glioblastoma cells. In the absence of Wnt3a, protein kinase R phosphorylated KDM4C at Ser918, inducing KDM4C ubiquitination and degradation. Wnt3a stabilized KDM4C through inhibition of GSK3-dependent protein kinase R activity. Stabilized KDM4C accumulated in the nucleus and bound to and demethylated TCF4-associated histone H3K9 by interacting with β-catenin, promoting HP1γ removal and transcriptional activation. These findings reveal that Wnt-KDM4C-β-catenin signaling represents a novel mechanism for the transcription of Wnt target genes and regulation of tumorigenesis, with important clinical implications. SIGNIFICANCE: These findings identify the Wnt-KDM4C-β-catenin signaling axis as a critical mechanism for glioma tumorigenesis that may serve as a new therapeutic target in glioblastoma.

Silencing microRNA-221/222 cluster suppresses glioblastoma angiogenesis by suppressor of cytokine signaling-3-dependent JAK/STAT pathway.

Angiogenesis is a major pathologic characteristic of glioblastoma, which is one aggressive primary brain tumor. MicroRNA-221/222 (miR-221/222) cluster has been previously reported to function importantly in malignant glioma biological process. The current study aims at evaluating the effects of miR-221/222 cluster on angiogenesis of glioblastoma cells. Microarray data were analyzed to select glioblastoma-associated differentially expressed genes, and dual-luciferase reporter assay was performed to assess targeting correlation between miR-221/222 cluster and suppressor of cytokine signaling-3 (SOCS3). Subsequently, the expression patterns of miR-221 and miR-222 in glioblastoma cells were identified. miR-221 and miR-222 were overexpressed or silenced in glioblastoma cells to identify the effect of miR-221/222 cluster in cell invasion, migration, proliferation, and angiogenesis. To define downstream pathway of miR-221/222 cluster or SOCS3 in glioblastoma, levels of Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway-related proteins were assessed. Additionally, the functions of miR-221/222 on glioblastoma cell angiogenesis were measured in vivo with microvessel density assayed. miR-221 and miR-222 were expressed at a high level and SOCS3 was at a low level in glioblastoma. Downregulation of the miR-221/222 cluster diminished the invasion, migration, proliferation, and angiogenesis with reduced protein levels of matrix metalloproteinase-2 (MMP-2), MMP-9, and vascular endothelial growth factor in glioblastoma cells. Also, silencing miR-221/222 cluster reduced p-JAK2/JAK2 and p-STAT3/STAT3. Consistently, the inhibitory role of silencing miR-221/222 cluster on tumorigenesis of glioblastoma cells was confirmed in vivo. Collectively, the inhibition of miR-221/222 cluster could attenuate the glioblastoma angiogenesis through inactivation of the JAK/STAT pathway by upregulating SOCS3.

Retracted] FOXO1 is crucial in glioblastoma cell tumorigenesis and regulates the expression of SIRT1 to suppress senescence in the brain.

The first author, Han Yan, wishes to retract the above article entitled 'FOXO1 is crucial in glioblastoma cell tumorigenesis and regulates the expression of SIRT1 to suppress senescence in the brain' to be published in Molecular Medicine Reports17: 2535-2542, 2018. The article was submitted by the first author without the prior knowledge or authorization of the corresponding author, Anhua Wu, who did not participate in the design, preparation or the writing of the paper. The first author apologizes for the inconvenience caused in this regard. [The original article was published in Molecular Medicine Reports 17: 2535-2542, 2018; DOI: 10.3892/mmr.2017.8146].

FOXO1 is crucial in glioblastoma cell tumorigenesis and regulates the expression of SIRT1 to suppress senescence in the brain.

In the present study, the role of Forkhead Box O1 (FOXO1) in glioblastoma (GBM) cell tumorigenesis was examined and the underlying mechanisms were investigated. Reverse transcription‑quantitative polymerase chain reaction and western blot analyses were used to analyze the expression of FOXO1 in GBM cell lines (LN18 and T98G) and tissues. Compared with the control groups, FOXO1 was significantly downregulated in the GBM tissues and GBM cell lines (P<0.05). The effects of the expression of FOXO1 on GBM cell proliferation and cell cycle were examined using flow cytometry. The overexpression of FOXO1 markedly inhibited LN18 and T98G cell proliferation and arrested cell cycle at the G0/G1 phase. In addition, FOXO1 facilitated cell senescence through regulation of the expression of sirtuin1. Epithelial‑mesenchymal transition (EMT) is a complex process, which affects cell growth, invasion and metastasis. The results of the present study revealed that FOXO1 inhibited EMT and metastasis in GBM. These finding revealed a novel mechanism of FOXO1 in the suppression of tumorigenesis and metastasis of GBM cells and suggested that FOXO1 may be a potential therapeutic target for treating GBM.

Stabilization of LSD1 by deubiquitinating enzyme USP7 promotes glioblastoma cell tumorigenesis and metastasis through suppression of the p53 signaling pathway.

The substrates and mechanisms of ubiquitin specific peptidase7(USP7) in glioma remain unclear. Lysine‑specific demethylase1(LSD1) may undergo proteasomal degradation; however, a reciprocal mechanism that stabilizes LSD1 in glioma has not been dertermined. Here co-immunoprecipitation and GST pull-down assays revealed that LSD1 is associated with USP7 invivo and invitro. USP7 inhibited LSD1 ubiquitination and stabilized LSD1 in A172 and T98G cells. MTT, EdU proliferation, flow cytometry and Transwell assays indicated that LSD1 played a critical role in the proliferation and invasion of glioblastoma(GBM) cells. We defined the mechanism of USP7 in GBM, through counterbalanced LSD1 ubiquitylation. USP7 caused G0/G1 arrest, promoted tumorigenesis and invasion of A172 and T98G cells. We also uncovered the suppression of the p53 signaling pathway that mediated the activity of USP7 and LSD1. Furthermore, USP7 and LSD1 expression levels were higher in the 150glioma patients than these levels in normal brain tissues and were correlated with glioma progression. LSD1 was increased concurrently with USP7 during glioblastoma progression and both were predictors for worsened prognosis. Collectively, our study suggested that USP7-LSD1 affects GBM cell proliferation and invasion and may be valuable as novel therapeutic targets and prognostic tools for GBM.