Apoptosis In Human Glioblastoma Cells Research Articles

The Proteasome Inhibitor Marizomib Evokes Endoplasmic Reticulum Stress and Promotes Apoptosis in Human Glioblastoma Cells.

Proteasomes play an important role in the physiology of cancer cells, and inhibition of their activity may be used as a promising therapeutic strategy against glioblastoma (GBM). Although certain proteasome inhibitors (PIs) have been approved for the treatment of other malignancies, they have limited effectiveness against GBM due to low brain bioavailability. Marizomib (MZB) is an irreversible, second-generation proteasome inhibitor, which unlike other PIs can penetrate through the blood-brain barrier, making it a promising therapeutic tool in brain malignancies. The antitumor activity of MZB was investigated in LN229 and U118 cells. The MTT test and the ATP-based assay were performed to evaluate cytotoxicity. Flow cytometry analysis was used to determine the apoptotic death of GBM cells. Luminescent assays were used to assess levels of reactive oxygen species (ROS) and the activity of caspase 3/7. RT-qPCR and Western blot analyses were used to determine gene and protein expressions. Marizomib decreased the viability and caused apoptotic death of GBM cells. The proapoptotic effect was accompanied by activation of caspase 3 and overexpression of cl-PARP, Noxa, Cyt C, and DR5. Moreover, treatment with MZB triggered endoplasmic reticulum (ER) stress, as shown by increased expressions of GRP78, IRE1α, p-EIF2α, p-SAPK/JNK, CHOP, ATF6α, and ATF4. On the contrary, overproduction of ROS or increased expressions of ERO1α, LC3 II, Beclin 1, and ATG5 were not detected, suggesting that neither oxidative stress nor autophagy were involved in the process of MZB-induced cell death. Thus, marizomib represents a potentially promising compound for facilitating further progress in brain cancer therapy.

Effect of pyridoxine or cobalamin supplementation on apoptosis and cell cycle progression in a human glioblastoma cell line

Glioblastoma is the most aggressive type of brain tumor, with current therapies failing to significantly improve patient survival. Vitamins have important effects on cellular processes that are relevant for tumor development and progression. Aim The present study explored the effect of pyridoxine or cobalamin supplementation on the viability and cell cycle progression of human glioblastoma cell line U-87 MG. Method Cell cultures were treated with increasing concentrations of pyridoxine or cobalamin for 24–72 h. After supplementation, cell viability and cell cycle progression were assessed by spectrophotometry and flow cytometry. Analysis of Bcl-2 and active caspase 3 expression in supplemented cells was performed by western blot. Result The results show that pyridoxine supplementation decreases cell viability in a dose and time dependent manner. Loss of viability in pyridoxin-supplemented cells is probably related to less cell cycle progression, higher active caspase 3 expression and apoptosis. In addition, Bcl-2 expression did not appear to be altered by vitamin supplementation, but active caspase 3 expression was significantly increased in pyridoxine-, but not cobalamin-supplemented cells, furthermore, cobalamin inhibited the pyridoxine cytotoxicity in the cell viability assay when combined Conclusion The results suggest that pyridoxine supplementation promotes apoptosis in human glioblastoma-derived cells and may be useful to enhance the effect of cytotoxic therapies in vivo.

Molecular Mechanisms of the Cytotoxic Effect of Recombinant Selenoprotein SELENOM on Human Glioblastoma Cells

Currently, selenobiology is an actively developing area, primarily due to the study of the role of the trace element selenium and its organic and inorganic compounds in the regulation of vital processes occurring in the cell. In particular, the study of the functions of selenium nanoparticles has gained great popularity in recent years. However, a weak point in this area of biology is the study of the functions of selenoproteins, of which 25 have been identified in mammals to date. First of all, this is due to the difficulties in obtaining native forms of selenoproteins in preparative quantities, due to the fact that the amino acid selenocysteine is encoded by one of the three stop codons of the TGA universal genetic code. A complex system for recognizing a given codon as a selenocysteine codon has a number of features in pro- and eukaryotes. The selenoprotein SELENOM is one of the least studied mammalian selenoproteins. In this work, for the first time, studies of the molecular mechanisms of regulation of the cytotoxic effect of this protein on human glioblastoma cells were carried out. The cytotoxicity of cancer cells in our experiments was already observed when cells were exposed to 50 μg of SELENOM and increased in proportion to the increase in protein concentration. Apoptosis of human glioblastoma cells was accompanied by an increase in mRNA expression of a number of pro-apoptotic genes, an increase in endoplasmic reticulum stress, and activation of the UPR IRE1α signaling pathway. The results obtained also demonstrate a dose-dependent depletion of the Ca2+ pool under the action of SELENOM, which proves the important role of this protein in the regulation of calcium homeostasis in the cell.

Angelica sinensis extract induces telomere dysfunction, cell cycle arrest, and mitochondria-mediated apoptosis in human glioblastoma cells.

Glioblastoma (GB) is one of the most aggressive and malignant tumors of the central nervous system. Conventional treatment for GB requires surgical resection followed by radiotherapy combined with temozolomide chemotherapy; however, the median survival time is only 12-15 months. Angelica sinensis Radix (AS) is commonly used as a traditional medicinal herb or a food/dietary supplement in Asia, Europe, and North America. This study aimed to investigate the effect of AS-acetone extract (AS-A) on the progression of GB and the potential mechanisms underlying its effects. The results indicated that AS-A used in this study showed potency in growth inhibition of GB cells and reduction of telomerase activity. In addition, AS-A blocked the cell cycle at the G0/G1 phase by regulating the expression of p53 and p16. Furthermore, apoptotic morphology, such as chromatin condensation, DNA fragmentation, and apoptotic bodies, was observed in AS-A-treated cells, induced by the activation of the mitochondria-mediated pathway. In an animal study, AS-A reduced tumor volume and prolonged lifespans of mice, with no significant changes in body weight or obvious organ toxicity. This study confirmed the anticancer effects of AS-A by inhibiting cell proliferation, reducing telomerase activity, altering cell cycle progression, and inducing apoptosis. These findings suggest that AS-A has great potential for development as a novel agent or dietary supplement against GB.

Expression of concern: Overexpression of FADD and Caspase-8 inhibits proliferation and promotes apoptosis of human glioblastoma cells. [Biomedicine & Pharmacotherapy 93 (2017) 1–7

Expression of concern: Overexpression of FADD and Caspase-8 inhibits proliferation and promotes apoptosis of human glioblastoma cells. [Biomedicine & Pharmacotherapy 93 (2017) 1–7

BTBD10 inhibits glioma tumorigenesis by downregulating cyclin D1 and p-Akt

The aim of this study was to investigate the role of BTBD10 in glioma tumorigenesis. The mRNA and protein levels of BTBD10 in 52 glioma tissues and eight normal brain tissues were determined using reverse transcription polymerase chain reaction (RT-PCR) and western blot analysis, respectively. U251 human glioblastoma cells were infected with BTBD10-expressing or control lentiviruses. Cell growth was evaluated using the methyl thiazolyl tetrazolium (MTT) assay. Cell apoptosis and cell cycle distribution were analyzed using flow cytometry. Cyclin D1 and p-Akt levels were determined using western blot analysis. The results showed that BTBD10 mRNA and protein levels were significantly lower in glioma tissues than in normal brain tissues. Additionally, BTBD10 levels were significantly lower in high-grade gliomas than in low-grade tumors. Compared with control cells, U251 cells overexpressing BTBD10 exhibited decreased cell proliferation, increased cell accumulation at the G0/G1 phase, increased cell apoptosis, and decreased levels of cyclin D1 and p-Akt. These findings show that BTBD10 is downregulated in human glioma tissue and that BTBD10 expression negatively correlates with the pathological grade of the tumor. Furthermore, BTBD10 overexpression inhibits proliferation, induces G0/G1 arrest, and promotes apoptosis in human glioblastoma cells by downregulating cyclin D1- and Akt-dependent signaling pathways.

Opuntiol Inhibits Growth and Induces Apoptosis in Human Glioblastoma Cells by Upregulating Active Caspase 3 Expression.

Background:Glioblastoma Multiforme (GBM) is a deadly tumor with poor prognosis. Resistance to apoptosis considered as an important factor in treatment failure. Therefore, identification of new compounds that facilitates apoptosis is crucial. Natural Anti-inflammatory compounds have emerged as potential anti-cancer agents and should be explored for their apoptotic activity against GBM. Therefore, the present study aims to evaluate growth inhibitory and apoptotic activity of a natural anti-inflammatory compound “Opuntiol” against GBM cell line U87.Methods:MTT assay was performed to determine the effect of Temozolomide and Opuntiol on growth inhibition of U87 cell. While, TUNEL assay was used to assess their apoptotic activity. To further assess apoptosis, nuclear condensation and nuclear area factor (NAF) was evaluated through DAPI staining. Whereas, active caspase-3 protein expression determined using immunocytochemistry. Results:Significant growth inhibition was observed in U87 cells treated with Temozolomide (IC50 380 µM) and Opuntiol (IC50 357 µM). Temozolomide (p<0.001) and Opuntiol (p<0.001) significantly improved rate of apoptosis when compared to control group. A significant decrease in NAF was also observed in Temozolomide (p < 0.05) and Opuntiol (p < 0.05) treated cells. There was a significant increase in active caspase-3 expression when observed in Temozolomide (p<0.001) and Opuntiol (p<0.05) treated groups as compared to control. Conclusion:In conclusion our findings suggests, Opuntiol repress cell viability and possess strong apoptotic activity against GBM cell line U-87. However, further mechanistic studies will be required to confirm whether it can be develop as a potential drug against GBM.

Mechanism of Ca2+-Dependent Pro-Apoptotic Action of Selenium Nanoparticles, Mediated by Activation of Cx43 Hemichannels.

Simple SummaryThe development of new methods of anticancer therapy is an urgent task of modern biology. The use of selenium and its compounds as anticancer drugs have already been shown to be effective. At the same time, the problem of selective delivery of selenium to organs and tissues remains. Nanoparticles are a promising and effective form of selenium delivery. This work is devoted to the study of the molecular and cellular mechanisms of action of selenium nanoparticles on glioblastoma cells. Using fluorescence microscopy and PCR, we were able to show for the first time the complete Ca2+ signaling pathway activated by selenium nanoparticles and the correlation between an increase in Ca2+ ions in the cytosol of cells with the induction of apoptosis. The presented study contributes to understanding the fundamental mechanisms of activation of programmed cell death in cancer tissue.To date, there are practically no data on the mechanisms of the selenium nanoparticles action on calcium homeostasis, intracellular signaling in cancer cells, and on the relationship of signaling pathways activated by an increase in Ca2+ in the cytosol with the induction of apoptosis, which is of great importance. The study of these mechanisms is important for understanding the cytotoxic effect of selenium nanoparticles and the role of this microelement in the regulation of carcinogenesis. The work is devoted to the study of the role of selenium nanoparticles obtained by laser ablation in the activation of the calcium signaling system and the induction of apoptosis in human glioblastoma cells (A-172 cell line). In this work, it was shown for the first time that the generation of Ca2+ signals in A-172 cells occurs in response to the application of various concentrations of selenium nanoparticles. The intracellular mechanism responsible for the generation of these Ca2+ signals has also been established. It was found that nanoparticles promote the mobilization of Ca2+ ions from the endoplasmic reticulum through the IP3-receptor. This leads to the activation of vesicular release of ATP through connexin hemichannels (Cx43) and paracrine cell activation through purinergic receptors (mainly P2Y). In addition, it was shown that the activation of this signaling pathway is accompanied by an increase in the expression of pro-apoptotic genes and the induction of apoptosis. For the first time, the role of Cx43 in the regulation of apoptosis caused by selenium nanoparticles in glioblastoma cells has been shown. It was found that inhibition of Cx43 leads to a significant suppression of the induction of apoptosis in these cells after 24 h treatment of cells with selenium nanoparticles at a concentration of 5 µg/mL.

Using ultrasound-targeted microbubble destruction to enhance radiotherapy of glioblastoma

ObjectiveTo investigate the efficacy and mechanism of ultrasound-targeted microbubble destruction (UTMD) combined with radiotherapy (XRT) on glioblastoma.MethodsThe enhanced radiosensitization by UTMD was assessed through colony formation and cell apoptosis in Human glioblastoma cells (U87MG). Subcutaneous transplantation tumors in 24 nude mice implanted with U87MG cells were randomly assigned to 4 different treatment groups (Control, UTMD, XRT, and UTMD + XRT) based on tumor sizes (100–300 mm3). Tumor growth was observed for 10 days after treatment, and then histopathology stains (HE, CD34, and γH2AX) were applied to the tumor samples. A TUNEL staining experiment was applied to detect the apoptosis rate of mice tumor samples. Meanwhile, tissue proteins were extracted from animal specimens, and the expressions of dsDNA break repair-related proteins from animal specimens were examined by the western blot.ResultsWhen the radiotherapy dose was 4 Gy, the colony formation rate of U87MG cells in the UTMD + XRT group was 32 ± 8%, lower than the XRT group (54 ± 14%, p < 0.01). The early apoptotic rate of the UTMD + XRT group was 21.1 ± 3% at 48 h, higher than that of the XRT group (15.2 ± 4%). The tumor growth curve indicated that the tumor growth was inhibited in the UTMD + XRT group compared with other groups during 10 days of observation. In TUNEL experiment, the apoptotic cells of the UTMD + XRT group were higher than that of the XRT group (p < 0.05). The UTMD + XRT group had the lowest MVD value, but was not significantly different from other groups (p > 0.05). In addition, γH2AX increased due to the addition of UTMD to radiotherapy compared to XRT in immunohistochemistry (p < 0.05).ConclusionsOur study clearly demonstrated the enhanced destructive effect of UTMD combined with 4 Gy radiotherapy on glioblastoma. This could be partly achieved by the increased ability of DNA damage of tumor cells.

Sulforaphane-cysteine downregulates CDK4 /CDK6 and inhibits tubulin polymerization contributing to cell cycle arrest and apoptosis in human glioblastoma cells.

Here we demonstrated that sulforaphane-cysteine (SFN-Cys) regulated cell cycle-related protein expressions in G0/G1 and G2/M phases of U87MG cells via High Performance Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (HPLC-MS/MS) and proteomics analysis. Further, mRNA products of CDK4, CDK6 and α-tubulin were significantly higher in glioblastoma than those in normal tissues, and these results were significantly correlated to pathological grades and clinical prognosis via analyzing TCGA and CGGA databases. Furthermore, Western blot showed that SFN-Cys downregulated CDK4, CDK6 and p-Rb in a dose-dependent manner and these results were reversed by p-ERK1/2 blocker PD98059 in U87MG and U373MG cells. The reductions of CDK4, CDK6 and p-Rb were reversed by proteasome inhibitor MG132; similarly, the upregulation of 26S proteasome by SFN-Cys was reversed by PD98059. Interestingly, SFN-Cys decreased CDK4 and CDK6 by phosphorylated ERK1/2-caused proteasomal degradation resulting in decreased Rb phosphorylation contributing to cell cycle arrest in G0/G1 phase. Besides, Western blot showed that SFN-Cys downregulated α-tubulin resulting in microtubule disruption and aggregation, and cell cycle arrest in G2/M phase and apoptosis. These results might help us understand the molecular etiology of glioblastoma progression to establish brand-new anti-cancer therapies.

PI3K/mTORC1/2 inhibitor PQR309 inhibits proliferation and induces apoptosis in human glioblastoma cells.

Glioblastoma (GBM) is the most common type of primary central nervous system tumor in adults, which has high mortality and morbidity rates, and short survival time, namely <15 months after the diagnosis and application of standard therapy, which includes surgery, radiation therapy and chemotherapy; thus, novel therapeutic strategies are imperative. The activation of the PI3K/AKT signaling pathway plays an important role in GBM. In the present study, U87 and U251 GBM cells were treated with the PI3K/mTORC1/2 inhibitor PQR309, and its effect on glioma cells was investigated. Cell Counting Kit-8 assay, 5-ethynyl-2′-deoxyuridine and colony formation assays revealed dose- and time-dependent cytotoxicity in glioma cells that were treated with PQR309. Flow cytometry and western blotting revealed that PQR309 can significantly induce tumor cell apoptosis and arrest the cell cycle in the G1 phase. Furthermore, the expression levels of AKT, phosphorylated (p)-AKT, Bcl-2, Bcl-xL, Bad, Bax, cyclin D1, cleaved caspase-3, MMP-9 and MMP-2 were altered. In addition, the migration and invasion of glioma cells, as detected by wound healing, migration and Transwell invasion assays, exhibited a marked suppression after treating the cells with PQR309. These results indicated that PQR309 exerts an antitumor effect by inhibiting proliferation, inducing apoptosis, inducing G1 cell cycle arrest, and inhibiting invasion and migration in human glioma cells. The present study provides evidence supportive of further development of PQR309 for adjuvant therapy of GBM.

AnvirzelTMregulates cell death through inhibiting GSK-3 activity in human U87 glioma cells

ABSTRACTObjectives: Cardiac glycosides are used as potential anti-cancer agents due to their effects on the inhibition of proliferation and induction of apoptosis and/or autophagy in cancer cells. Herein, we aimed to study the potential signaling pathways taken role in differential cell-death properties of AnvirzelTM which is consisted of two toxic cardiac glycosides (oleandrin and oleandrigenin), in U87 human glioblastoma cells.Methods: The anti-proliferative and anti-migratory effects of AnvirzelTM were assessed in U87 cells by WST-1 assay and wound healing assay, respectively. After treatment of AnvirzelTMwith doses of 10, 25, 50, 100 and 250 μg/ml, expression levels of proteins related to cell death were investigated by Western blot.Results: Anvirzel™ markedly inhibited the growth of U87 cells in a time- and dose-dependent manner following 24 h and 48 h treatments (p < 0.05). In addition, it was found that Anvirzel™ inhibited GSK-3, NOS and HIF1-α expressions whereas activated ERK in U87 cells compared to vehicle (p < 0.05).Discussion: The results suggested that AnvirzelTM regulated cell death distinctly from apoptosis in human glioblastoma cells. Further studies are required for validation of mechanistic insights about the potential signaling pathways taken role in differential cell death properties of AnvirzelTM.

Mitochondrial dysfunction contributes to Rapamycin-induced apoptosis of Human Glioblastoma Cells - A synergistic effect with Temozolomide.

Mammalian target of rapamycin (mTOR) is upregulated in a high percentage of glioblastomas. While a well-known mTOR inhibitor, rapamycin, has been shown to reduce glioblastoma survival, the role of mitochondria in achieving this therapeutic effect is less well known. Here, we examined mitochondrial dysfunction mechanisms that occur with the suppression of mTOR signaling. We found that, along with increased apoptosis, and a reduction in transformative potential, rapamycin treatment significantly affected mitochondrial health. Specifically, increased production of reactive oxygen species (ROS), depolarization of the mitochondrial membrane potential (MMP), and altered mitochondrial dynamics were observed. Furthermore, we verified the therapeutic potential of rapamycin-induced mitochondrial dysfunction through co-treatment with temzolomide (TMZ), the current standard of care for glioblastoma. Together these results demonstrate that the mitochondria remain a promising target for therapeutic intervention against human glioblastoma and that TMZ and rapamycin have a synergistic effect in suppressing glioblastoma viability, enhancing ROS production, and depolarizing MMP.

MerTK inhibition decreases immune suppressive glioblastoma-associated macrophages and neoangiogenesis in glioblastoma microenvironment.

Glioblastoma-associated macrophages and microglia (GAMs) are the predominant immune cells in the tumor microenvironment. Activation of MerTK, a receptor tyrosine kinase, polarizes GAMs to an immunosuppressive phenotype, promoting tumor growth. Here, the role of MerTK inhibition in the glioblastoma microenvironment is investigated in vitro and in vivo. Effects of MRX-2843 in glioblastoma microenvironment regulation were determined in vitro by cell viability, cytokine array, in vitro tube formation, Western blotting, and wound healing assays. A syngeneic GL261 orthotopic glioblastoma mouse model was used to evaluate the survival benefit of MRX-2843 treatment. Multiplex fluorescent immunohistochemistry was used to evaluate the expression of CD206, an anti-inflammatory marker on GAMs, and angiogenesis in murine brain tumor tissues. MRX-2843 inhibited cell growth and induced apoptosis in human glioblastoma cells and decreased protein expression of phosphorylated MerTK, AKT, and ERK, which are essential for cell survival signaling. Interleukin-8 and C-C motif chemokine ligand 2, the pro-glioma and pro-angiogenic cytokines, were decreased by MRX-2843. Decreased vascular formation and numbers of immunosuppressive (CD206+) GAMs were observed following MRX-2843 treatment in vivo, suggesting that in addition to alleviating immunosuppression, MRX-2843 also inhibits neoangiogenesis in the glioma microenvironment. These results were supported by a prolonged survival in the syngeneic mouse orthotopic GL261 glioblastoma model following MRX-2843 treatment. Our findings suggest that MRX-2843 has a therapeutic benefit via promoting GAM polarization away from immunosuppressive condition, inhibiting neoangiogenesis in the glioblastoma microenvironment and inducing tumor cell death.

GALE Promotes the Proliferation and Migration of Glioblastoma Cells and Is Regulated by miR-let-7i-5p.

PurposeGlioma is the most common and lethal type of brain tumor. While GALE (UDP-galactose-4-epimerase) has been shown to be overexpressed in some kinds of cancers, its expression in gliomas has not been reported. MicroRNAs (miRNAs) function as tumor suppressors in many cancers, and online datasets can be used to predict whether GALE is regulated by miR-let-7i-5p. In this investigation, we explored the effect and regulatory mechanisms of GALE on glioblastoma growth via miR-let-7i-5p.MethodsWe used a Cox proportional hazards model and publicly available datasets to examine the relationship between GALE and the survival rates of glioma patients. Bioinformatics predicted the targeting of GALE by miR-let-7i-5p. The proliferation, migration, cell cycle and apoptosis of human glioblastoma cells were assessed by relevant assays. We also demonstrated the effect of GALE on glioblastoma multiforme [GBM] tumor growth using an in vivo orthotopic xenograft model.ResultsGALE was upregulated in human gliomas, especially in high-grade gliomas (e.g., GBM). An obvious decline in GALE expression was observed in human glioblastoma cell lines (U87 and U251) following treatment with a small interfering RNA (siRNA) targeting GALE or miR-let-7i-5p mimics. Knockdown of GALE or overexpression of miR-let-7i-5p (with miR-let-7i-5p mimics) inhibited U87 and U251 cell growth. miR-let-7i-5p significantly restrained the migration ability of human glioblastoma cells in vascular mimic (VM), wound healing and transwell assays, and GALE promoted glioblastoma growth in vivo.ConclusionOur findings confirm that GALE plays an important role in promoting the development of human glioma and that GALE can be regulated by miR-let-7i-5p to inhibit human glioblastoma growth.Implications for cancer survivorsOur data show that cancer survivors have low GALE expression, which indicates that GALE may be a diagnostic biomarker and a promising therapeutic target in glioblastoma.

α-Hispanolol Induces Apoptosis and Suppresses Migration and Invasion of Glioblastoma Cells Likely via Downregulation of MMP-2/9 Expression and p38MAPK Attenuation

α-Hispanolol (α-H) is a labdane diterpenoid that has been shown to induce apoptosis in several human cancer cells. However, the effect of α-H in human glioblastoma cells has not been described. In the present work, we have investigated the effects of α-H on apoptosis, migration, and invasion of human glioblastoma cells with the aim of identifying the molecular targets underlying its mechanism of action. The results revealed that α-H showed significant cytotoxicity against human glioma cancer cell lines U87 and U373 in a concentration- and time-dependent manner. This effect was higher in U87 cells and linked to apoptosis, as revealed the increased percentage of sub-G1 population by cell cycle analysis and acquisition of typical features of apoptotic cell morphology. Apoptosis was also confirmed by significant presence of annexin V-positive cells and caspase activation. Pretreatment with caspase inhibitors diminishes the activities of caspase 8, 9, and 3 and maintains the percentage of viable glioblastoma cells, indicating that α-H induced cell apoptosis through both the extrinsic and the intrinsic pathways. Moreover, we also found that α-H downregulated the anti-apoptotic Bcl-2 and Bcl-xL proteins and activated the pro-apoptotic Bid and Bax proteins. On the other hand, α-H exhibited inhibitory effects on the migration and invasion of U87 cells in a concentration-dependent manner. Furthermore, additional experiments showed that α-H treatment reduced the enzymatic activities and protein levels of matrix metalloproteinase MMP-2 and MMP-9 and increased the expression of TIMP-1 inhibitor, probably via p38MAPK regulation. Finally, xenograft assays confirmed the anti-glioma efficacy of α-H. Taken together, these findings suggest that α-H may exert anti-tumoral effects in vitro and in vivo through the inhibition of cell proliferation and invasion as well as by the induction of apoptosis in human glioblastoma cells. This research describes α-H as a new drug that may improve the therapeutic efficacy against glioblastoma tumors.

Nanoparticle-mediated intratumoral inhibition of miR-21 for improved survival in glioblastoma

Glioblastoma (GBM) is the most common and deadly form of malignant brain tumor in the United States, and current therapies fail to provide significant improvement in survival. Local delivery of nanoparticles is a promising therapeutic strategy that bypasses the blood-brain barrier, minimizes systemic toxicity, and enhances intracranial drug distribution and retention. Here, we developed nanoparticles loaded with agents that inhibit miR-21, an oncogenic microRNA (miRNA) that is strongly overexpressed in GBM compared to normal brain tissue. We synthesized, engineered, and characterized two different delivery systems. One was designed around an anti-miR-21 composed of RNA and employed a cationic poly(amine-co-ester) (PACE). The other was designed around an anti-miR-21 composed of peptide nucleic acid (PNA) and employed a block copolymer of poly(lactic acid) and hyperbranched polyglycerol (PLA-HPG). We show that both nanoparticle products facilitate efficient intracellular delivery and miR-21 suppression that leads to PTEN upregulation and apoptosis of human GBM cells. Further, when administered by convection-enhanced delivery (CED) to animals with intracranial gliomas, they both induced significant miR-21 knockdown and provided chemosensitization, resulting in improved survival when combined with chemotherapy. The challenges involved in optimizing the two delivery systems differed, and despite offering distinct advantages and limitations, results showed significant therapeutic efficacy with both methods of treatment. This study demonstrates the feasibility and promise of local administration of miR-21 inhibiting nanoparticles as an adjuvant therapy for GBM.

PI3Kβ inhibitor AZD6482 exerts antiproliferative activity and induces apoptosis in human glioblastoma cells.

Glioblastoma is the most common type of primary brain tumour in adults, and its pathogenesis is particularly complicated. Among the many possible mechanisms underlying its pathogenesis, hyperactivation of the PI3K/Akt pathway is essential to the occurrence and development of glioma through the loss of PTEN or somatic activating mutations in PIK3CA. In the present study, we investigated the effect of the PI3Kβ inhibitor AZD6482 on glioma cells. The CCK-8 assay showed dose-dependent cytotoxicity in glioma cell lines treated with AZD6482. Additionally, AZD6482 treatment was found to significantly induce apoptosis and cell cycle arrest as detected using flow cytometry. Moreover, as shown using western blot analysis, the levels of p-AKT, p-GSK-3β, Bcl-2, and cyclin D1 were decreased after AZD6482 treatment. In addition, we found that AZD6482 inhibited the migration and invasion of glioma cells as detected by wound healing and Transwell invasion assays. Taken together, our findings indicate that AZD6482 exerts an antitumour effect by inhibiting proliferation and inducing apoptosis in human glioma cells. AZD6482 may be applied as an adjuvant therapy to improve the therapeutic efficacy of glioblastoma treatment.

RRM2 promotes the progression of human glioblastoma.

Glioblastoma pathogenesis is related to multiple processes that affected by dozens of regulatory factors, but the potential underlying factors regulating glioblastoma progression remains unclear. The goal of this research was to determine how the ribonucleotide reductase M2 subunit (RRM2) influenced proliferation, invasion, migration, and apoptosis of human glioblastoma cells. The level of proliferation of human glioblastoma cells was measured through CCK8, colony formation assay and immunofluorescence stains. Flow cytometry (FCM), wound healing, and transwell assays were conducted to detect cell apoptosis, migration, and invasion. Apoptotic level of cells and invasion-related expression of protein were measured by Western blot. Xenograft tumor model was established to confirm effect of RRM2 on the proliferation of human glioblastoma cells in vivo. Silencing RRM2 inhibited proliferation, invasion, and migration of glioblastoma cells whereas enhanced apoptosis rate. Overexpressing RRM2 promoted proliferation, migration and invasion but suppressed apoptosis. In vivo, Overexpressing RRM2 accelerated the tumor growth in glioblastoma cells. The present study illustrated that RRM2 was overexpressed in human glioblastoma cells. RRM2 promoted proliferation, migration, and invasion but inhibited apoptosis of human glioblastoma cells.

Interference with PSMB4 Expression Exerts an Anti-Tumor Effect by Decreasing the Invasion and Proliferation of Human Glioblastoma Cells

Background/Aims: Glioblastoma (GBM) is a malignant brain tumor with a poor prognosis. Proteasome subunit beta type-4 (PSMB4) is an essential subunit that contributes to the assembly of the 20S proteasome complex. However, the role of PSMB4 in glioblastomas remains to be clarified. The aim of this study was to investigate the role of PSMB4 in GBM tumor progression. Methods: We first analyzed the PSMB4 protein and mRNA expression in 80 clinical brain specimens and 77 datasets from the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database. Next, we inhibited the PSMB4 expression by siRNA in cellular and animal models to explore PSMB4’s underlying mechanisms. The cell survival after siPSMB4 transfection was assayed by MTT assay. Annexin V and propidium iodide staining was used to monitor the apoptosis by flow cytometric analysis. Moreover, the migration and invasion were evaluated by wound healing and Transwell assays. The expression of migration-related and invasion-related proteins after PSMB4 inhibition was detected by Western blotting. In addition, an orthotropic xenograft mouse model was used to assay the effect of PSMB4 knockdown in the in vivo study. Results: Basis on the results of bioinformatics study, glioma patients with higher PSMB4 expression had a shorter survival time than those with lower PSMB4 expression. The staining of clinical brain tissues showed elevated PSMB4 expression in GBM tissues compared with normal brain tissues. The PSMB4 inhibition decreased proliferation, migration and invasion abilities in human GBM cells. Downregulated PSMB4 resulted in cell cycle arrest and apoptosis in vitro. In an orthotropic xenograft mouse model, the glioma tumors progression was reduced when PSMB4 was down-regulated. The decreased PSMB4 enhanced the anti-tumor effect of temozolomide (TMZ) on tumor growth. In addition, the absence of PSMB4 decreased the expression of phosphorylated focal adhesion kinase and matrix metallopeptidase 9 in vivo. Conclusion: PSMB4 inhibition in combination with TMZ may exert an anti-tumor effect by decreasing cell proliferation and invasion as well as by promoting apoptosis in human glioblastoma cells. This research may improve the therapeutic efficacy of glioblastoma treatment.