Malignant Nervous System Tumors Research Articles

A novel lncRNA-LINC01116 regulates tumorigenesis of glioma by targeting VEGFA.

Brain glioma is the most common malignant tumor of the central nervous system, and one of the leading causes of death in patients with intracranial tumors. The clinical outcome of glioma is usually poor due to abundant vascularity, fast growth and susceptibility of invasion to normal brain tissues. Our microarray study showed that lncRNA-LINC01116 was significantly upregulated in glioma tissues and played an important role in cell proliferation, cycle, migration, invasion and angiogenesis. In addition, vascular endothelial growth factor (VEGFA) may be the major target genes in the downstream of lncRNA-LINC01116. Dual luciferase assay showed that LINC01116 and VEGFA both contained a miR-31-5p binding site, and LINC01116 could regulate the expression of VEGFA through competitive absorption of miR-31-5p. RNA immunoprecipitation indicated that LINC01116 and VEGFA were present in the miR-31-5p-RISC complex, and biotinylated miR-31-5p pull-down assay suggested that there was a competitive relationship between LINC01116 and VEGFA to bind with miR-31-5p. Collectively, our study has identified a novel lncRNA-LINC01116 and clarified the role and mechanism of LINC01116 in the tumorigenesis of glioma. LINC01116 may prove to be a potential target for the clinical diagnosis and treatment of glioma.

Production and Evaluation of an Avian IgY Immunotoxin against CD133+ for Treatment of Carcinogenic Stem Cells in Malignant Glioma: IgY Immunotoxin for the Treatment of Glioblastoma.

Background Glioblastoma is the most common malignant tumor of Central Nervous System. Despite the research in therapeutics, the prognosis is dismal. Malignant glioma stem cells (MGSCs) are a major cause of treatment failure and increasing tumor recurrence. In general, cancer stem cells (CSCs) express prominin-1 (CD133), considered as a potential therapeutic target. In this study, we produced an avian immunotoxin directed against the subpopulation of CD133+ CSCs within a malignant glioma. We used the avian IgY because it has various advantages as increased affinity to mammal antigens and inexpensive obtention of large amounts of specific antibodies (approximately 1 mg/per egg). The design, production, purification and use of IgY anti CD133 immunotoxin constitute an original goal of this research. Methods The immunodominant peptide of CD133 was designed to immunize hens; also, the extracellular domain of CD133 was cloned to probe the IgY antibodies. In parallel, a recombinant abrin A chain was produced in E. coli in order to join it to the Fc domain of the anti-CD133 IgY to conform the immunotoxin. This anti-CD133 IgY anti-tumor immunotoxin was tested in vitro and in vivo. Results. The cytotoxicity of the immunotoxin in vitro showed that IgY-abrin immunotoxin reduced 55% cell viability. After subcutaneous MGSCs implantation, the animals treated intraperitoneally or intratumorally with the IgY-abrin immunotoxin showed more than 50% decrease of tumor volume. Conclusion Results showed that the IgY-abrin immunotoxin had cytotoxic activity against CD133+ MGSCs and provides a novel approach for the immunotherapy of glioblastoma.

CircPCMTD1 Acts as the Sponge of miR-224-5p to Promote Glioma Progression.

Glioma is the most common malignant tumor of the central nervous system with high morbidity and mortality. Circular RNAs (circRNAs) are abundant non-coding RNAs, which contribute to tumor progression by competing with other endogenous RNAs such as microRNA (miRNA). MiRNA are a class of small non-coding RNAs, which interrupt the translation of target mRNAs. CircPCMTD1 (hsa-circ-0001801) is a newly discovered circRNA that was found to be significantly upregulated in glioma. However, its function is unclear. In this study, circPCMTD1 upregulation promoted the cell viability, migration and invasion dramatically, while the inhibition of circPCMTD1 led to a significant reduction of tumor growth in vivo. MiRNAs microarray analyses on circPCMTD1 silencing models in U251 and U118MG cells were performed, and the results suggested that circPCMTD1 knockdown could upregulate the expression of miR-224-5p and downregulate the expression of mTOR, one of miR-224-5p targets, in both cell lines. According to the prediction from circular RNA interactome and Targetscan, there was a complementary sequence in circPCMTD1 for miR-224-5p. Dual-luciferase reporter assay demonstrated that circPCMTD1 were targets of miR-224-5p. RIP assay was also performed to further confirm their directly interaction. Overexpression of miR-224-5p inhibited the viability and proliferation, migration, and invasion of U251 and U118MG glioma cells. In conclusion, circPCMTD1 could contribute to the promotion of glioma progression, and it may serve as the sponge of miR-224-5p to exert its function.

Pristimerin inhibits glioma progression by targeting AGO2 and PTPN1 expression via miR-542-5p.

Glioblastoma multiform is the most common and malignant primary tumor of the central nervous system in adults, the high recurrence rate and poor prognosis are critical priorities. Pristimerin is a naturally occurring quinone methide triterpenoid isolated from the Celastraceae and Hippocrateaceae families. Its anticancer effects have garnered considerable attention; nonetheless, the mechanisms of action remain unknown. To predict the hub genes of pristimerin, PharmMapper and the Coremine database were used to identify 13 potential protein targets; protein–protein interaction, for which functional enrichment analyses were performed. Compound-target, target-pathway, and compound-target-pathway networks were constructed using Cytoscape. Biological process analysis first revealed that enrichment of these target genes correlated with negative regulation of symbiont growth in the host, and regulation of chronic inflammatory response to antigenic stimulus. Survival analysis in cBioPortal showed that protein tyrosine phosphatase, non-receptor type 1 (PTPN1) and Argonaute 2 (AGO2) might be involved in the carcinogenesis, invasion, or recurrence of diffuse glioma. In addition, we observed that low-dose pristimerin inhibited the viability of glioma cells, while miR-542-5p in vitro; and reduced PTPN1 expression. Notably, high-dose pristimerin induced apoptosis. Furthermore, miR-542-5p silence with siRNA in glioma cells lead to the elevation in AGO2, and decreased PTPN1 level. The effect was obviously post pristimerin treatment and miR-542-5p suppression. In conclusion, pristimerin inhibited glioma progression through AGO2 and PTPN1 expression via a canonical miRNA-mediated mechanism.

Targeted therapy based on p53 reactivation reduces both glioblastoma cell growth and resistance to temozolomide.

Glioblastoma(GB) is the most common and aggressive malignant tumor of the central nervous system. Despite current intensive treatment regimens, consisting of surgical resection followed by radiotherapy with concomitant and adjuvant temozolomide (TMZ) chemotherapy, the prognosis of patients with GB remains extremely poor. Considering that alterations of the p53 tumor suppressor pathway have a key role in both GB development and resistance to TMZ treatment, the re‑activation of p53 could be an effective therapeutic approach against GB. In this study, we challenged p53 wild‑type and mutant GB cell lines with RITA, a molecule originally identified for its ability to restore p53 functions, although it was subsequently shown to act also through p53‑independent mechanisms. We examined the effects of RITA on GB cell viability, through MTS and clonogenic assays, and analyzed cell death through cytoflourimetric analyses. In all the tested GB cell lines, RITA significantly reduced the cell proliferative and clonogenic potential and induced cell accumulation in the S and/or G2/M cell cycle phases and massive p53‑dependent apoptosis. Moreover, RITA was more effective than the well‑known p53 re‑activating molecule, nutlin‑3, and did not affect the viability of normal astrocytes. In addition, RITA decreased survivin expression and induced DNA damage, two mechanisms that likely contribute to its anti‑tumor effects. Furthermore, RITA synergized with TMZ and was able to decrease the expression of MGMT, which is a crucial player in TMZ resistance. Thus, although further studies are warranted to clarify the exact mechanisms of action of RITA, the data of this study suggest the potential of such an approach for GB therapy, which may also help to overcome resistance to TMZ.

Glutamate Receptors and Glioblastoma Multiforme: An Old "Route" for New Perspectives.

Glioblastoma multiforme (GBM) is the most aggressive malignant tumor of the central nervous system, with poor survival in both treated and untreated patients. Recent studies began to explain the molecular pathway, comprising the dynamic structural and mechanical changes involved in GBM. In this context, some studies showed that the human glioblastoma cells release high levels of glutamate, which regulates the proliferation and survival of neuronal progenitor cells. Considering that cancer cells possess properties in common with neural progenitor cells, it is likely that the functions of glutamate receptors may affect the growth of cancer cells and, therefore, open the road to new and more targeted therapies.

Evaluating the Association Between the Extent of Resection and Survival in Gliosarcoma.

Introduction: Gliosarcoma (GS) is a rare, malignant mixed tumor of the central nervous system with a median survival of approximately 13 months across multiple studies. Although the value of the extent of resection (EOR) has been confirmed as a prognostic survival factor in glioblastoma, no such association has been defined for GS. The goal of this study was to establish an association between EOR and survival and to determine if a threshold of resection exists for which a survival benefit is conferred in GS.Methods: The authors identified 11 patients with histologically confirmed GS between January 2005 and January 2015, treated at the Hospital of the University of Pennsylvania. Clinical, radiographic, and outcome data were retrospectively reviewed. Volumetric analysis was completed using semi-automated segmentation to measure the change in contrast-enhancing material based on preoperative T1-contrast (T1c) and postoperative T1 & T1c magnetic resonance imaging (MRI) scans. A log-rank test was completed to confirm an association between EOR and survival, and a series of Kaplan-Meier curves were constructed to determine an EOR threshold. Univariate Cox proportional hazards model (CPHM) followed by multivariate CPHM was also completed to evaluate associations between the prognostic clinical and immunohistochemistry variables under consideration.Results: Extent of resection categories were defined as gross total resection (GTR >95%), subtotal resection (STR 90%-95%), and partial resection (PR <90%). The median overall survival for the groups were as follows: GTR-17.3 months (n=4), STR-12.6 months (n=5), PR-4.3 months (n=2). A statistically significant association (p=05 level) was found between survival and the PR group with the GTR group as reference. Multivariate CPHM confirmed a statistically significant association between increased survival and age, preoperative Karnofsky Performance Status (KPS) scores, postoperative KPS scores, and KI-67 index. Serial Kaplan-Meier curves suggest a survival benefit with an EOR threshold of 94%.Conclusion: This study agrees with previous correlations in glioblastoma EOR and prolonged survival. For patients undergoing surgical resection for GS, maximal surgical removal, when safely possible, should be attempted as it appears to translate to longer survival times.

Tissue Specific Expression of Neurofibromin Isoforms in Swine

Neurofibromatosis type 1 (NF1) is one of the most common monogenic disorders and affects 1 in 2,500 children. The disorder manifests in varying, complex phenotypes that include cognitive and learning dysfunction, bone and cardiovascular disorders, and an increased risk of developing benign and malignant nervous system tumors. The neurofibromin gene contains 63 exons, of which four are alternatively spliced (optionally included) within isoforms of neurofibromin transcripts that are differentially expressed in specific tissues. Recently, several swine models of NF1 have been developed in hopes that these models will recapitulate the disorder in humans better than existing rodent models and thus offer a more translational platform for the development of novel therapies. However, the normal expression patter of neurofibromin isoforms in swine is unknown. In the current study, we characterize the tissue specific expression pattern of neurofibromin in swine to enable comparisons to that known in humans.Tissue samples taken from the cortex, cerebellum, pituitary, amygdala, hippocampus, substantia nigra, optic nerve, brachial nerve, adipose, skeletal muscle, small intestine, and colon of swine were used to determine mRNA expression levels for isoforms containing each of the four known alternatively spliced exons (ASEs). Mesenchymal stem cells isolated and cultured from adipose tissue were also included in the analysis. A standard qPCR approach was first used to determine in which tissues ASEs significantly varied. Then, droplet digital PCR was used to produce a more precise analysis of ASE expression pattern in targeted tissues. The level of total neurofibromin mRNA and the relative expression of each of the four ASEs were determined in the cultured MSCs and each tissue sample. The stem cells were found to have the highest expression of total neurofibromin mRNA, while nervous tissues containing gray matter and white matter showed 2‐ and 6‐ fold lower expression, respectively. Muscle tissue showed 14‐fold lower expression. Muscle and gray matter tissues had the highest relative expression of ASE 12 (a12), while the stem cells and white matter tissues had the highest relative expression of ASE 31 (a31). Muscle showed the most relative abundance of ASE 57 (a57). The expression of a12 and a57 were negligible in stem cells. Most malignant NF1 tumors originate from white matter and in this tissue, we observed higher relative levels of a31, an ASE that is known to influence Ras activity implicated in tumorigenesis. Overarchingly, our results are concordant with known patterns of ASE expression in corresponding human tissues and provide the first characterization of neurofibromin ASE expression in swine.Support or Funding InformationThe research was supported by the Biomedical &amp; Genomic Research Group Discretionary Fund (University of Wisconsin‐ Madison), NF North Central, NF Network, and NF Team Foundation.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Bufalin Induces Apoptosis and Improves the Sensitivity of Human Glioma Stem-Like Cells to Temozolamide.

Glioma is the most common malignant tumor of the central nervous system, and it is characterized by high relapse and fatality rates and poor prognosis. Bufalin is one of the main ingredients of Chan-su, a traditional Chinese medicine (TCM) extracted from toad venom. Previous studies revealed that bufalin exerted inhibitory effects on a variety of tumor cells. To demonstrate the inhibitory effect of bufalin on glioma cells and glioma stem-like cells (GSCs) and discuss the underlying mechanism, the proliferation of glioma cells was detected by MTT and colony formation assays following treatment with bufalin. In addition, we investigated whether bufalin inhibits or kills GSCs using flow cytometry, Western blotting, and reverse transcription polymerase chain reaction analysis (RT-PCR). Finally, we investigated whether bufalin could improve the therapeutic effect of temozolomide (TMZ) and discussed the underlying mechanism. Taken together, our data demonstrated that bufalin inhibits glioma cell growth and proliferation, inhibits GSC proliferation, and kills GSCs. Bufalin was found to induce the apoptosis of GSCs by upregulating the expression of the apoptotic proteins cleaved caspase 3 and poly(ADP-ribose) polymerase (PARP) and by downregulating the expression of human telomerase reverse transcriptase, which is a marker of telomerase activity. Bufalin also improved the inhibitory effect of TMZ on GSCs by activating the mitochondrial apoptotic pathway. These results suggest that bufalin damages GSCs, induces apoptosis, and enhances the sensitivity of GSCs to TMZ.

Carfilzomib enhances cisplatin-induced apoptosis in SK-N-BE(2)-M17 human neuroblastoma cells

Neuroblastoma is a solid malignant tumor of the sympathetic nervous system, which accounts for 8–10% of childhood cancers. Considering the overall high risk and poor prognosis associated with neuroblastoma, effective therapeutics should be developed to improve patient survival and quality of life. A recent study showed that a proteasome inhibitor, carfilzomib (CFZ), reduced cell viability of SK-N-BE(2)-M17 neuroblastoma cells. Therefore, we investigated the molecular mechanisms by which CFZ lower the cell viability of neuroblastoma cells. CFZ reduced cell viability via cell cycle arrest at G2/M and apoptosis, which involved caspase activation (caspases-8, 9, 4, and 3), endoplasmic reticulum stress, reactive oxygen species production, mitochondrial membrane potential loss, and autophagy in a dose- and time-dependent manner. The effect of CFZ was additive to that of cisplatin (Cis), a well-known chemotherapeutic drug, in terms of cell viability reduction, cell cycle arrest, and apoptosis. Importantly, the additive effect of CFZ was maintained in Cis-resistant neuroblastoma cells. These results suggest that CFZ can be used in combination therapy for patients with neuroblastoma to overcome the resistance and adverse side effects of Cis.

D,L-Methadone does not improve radio- and chemotherapy in glioblastoma in vitro.

Glioblastoma (GBM) is the most common malignant tumor of the central nervous system. Median survival of glioblastoma patients under standard therapy including radiotherapy and chemotherapy using temozolomide (TMZ) is 14.6 months. As cell culture experiments combining D,L-methadone with doxorubicin demonstrated an increased reduction of cell viability of glioblastoma cells, the opioid has been discussed as a drug for the treatment of GBM. Despite lack of clinical and experimental evidence that D,L-methadone in combination with standard therapy will be beneficial, an increasing number of tumor patients medicating themselves with D,L-methadone present to the hospitals in Germany. As a first step towards understanding whether D,L-methadone may increase the efficacy of standard therapy, we used a cell culture model of primary GBM and fibroblast cell cultures derived from GBM patients. The cultures were treated with different concentrations of D,L-methadone in combination with X-irradiation, TMZ or both. Cell viability was determined by measuring ATP in cell lysates and dehydrogenase activity in living cells. When only treated with D,L-methadone, 1µM of the opioid was sufficient to reduce viability of fibroblasts, whereas 10µM was needed to significantly reduce glioblastoma cell viability. In addition, D,L-methadone did not improve the anti-neoplastic effects of X-irradiation, temozolomide or both. As D,L-methadone reduces glioblastoma cell viability only when concentrations are used that had been reported to be toxic to patients and as there were no interactions observable combining it with standard therapy, a recommendation for the use of D,L-methadone in glioblastoma therapy cannot be given.

Seven genes for the prognostic prediction in patients with glioma.

Glioma is a common malignant tumor of the central nervous system, which is characterized by a low cure rate, high morbidity, and high recurrence rate. Consequently, it is imperative to explore some indicators for prognostic prediction in glioma. We obtained glioma data from The Cancer Genome Atlas (TCGA). Differentially expressed genes (DEGs) were obtained by R software from TCGA data sets. Through Cox regression analysis, risk scores were obtained to assess the weighted gene-expression levels, which could predict the prognosis of patients with glioma. The validity and the prognostic value of this model in glioma were confirmed by the manifestation of receiver-operating characteristic (ROC) curves, area under the curve (AUC), and 5-year overall survival (OS). In total, 920 DEGs of transcriptome genes in glioma were extracted from the TCGA database. We identified a novel seven-gene signature associated with glioma. Among them, AL118505.1 and SMOC1 were positively related to the 5-year OS of patients with glioma, showing a better prognosis for glioma; however, RAB42, SHOX2, IGFBP2, HIST1H3G, and IGF2BP3 were negatively related to 5-year OS, displaying a worse prognosis. In addition, according to risk scores, AL118505.1 was also a protective factor, while others were risk factors. Furthermore, the expression levels of SHOX2, IGFBP2, and IGF2BP3 were significantly positively correlated with glioma grades. Receiver-operating characteristic (ROC) curve assessed the accuracy and sensitivity of the gene signature. Each of the seven genes for patients with the distribution of the risk score was presented in the heat map. We identified a novel seven-gene signature in patients with glioma, which could be used as a predictor for the prognosis of patients with glioma in the future.

Adaptive functioning in children with neurofibromatosis type 1: relationship to cognition, behavior, and magnetic resonance imaging.

To characterize the adaptive behavior profile of children with neurofibromatosis type 1 (NF1) and determine its relationship to neuropsychological functioning and non-neoplastic T2-weighted hyperintense brain lesions on brain magnetic resonance imaging (MRI). In this cross-sectional study, we retrospectively reviewed neuropsychological reports from 104 children with NF1 (56 males, 48 females; mean age 10y 4mo; standard deviation [SD] 3y 4mo; range 3y 5mo-17y 6mo), and extracted data from a range of cognitive and behavioral measures, including the Adaptive Behavior Assessment System (ABAS). Brain MRI was retrospectively reviewed in 42 individuals. Adaptive Behavior Assessment System scores were continuously distributed and pathologically shifted by 0.79 to 1.26SD across Conceptual, Social, and Practical domains, and 46.5% of individuals had a composite score in the borderline or impaired range. Impairment in adaptive functioning was correlated with deficits in executive function (r=-9.543, p<0.001), externalizing problems (r=-0.366, p<0.001), and attention (r=-9.467, p=0.001). Cluster analysis revealed three distinct phenotypic subgroups, one of which exhibited normal cognitive ability, but impaired adaptive functioning, with persistent deficits in executive function, behavioral problems, and attention-deficit/hyperactivity disorder symptomatology. There was no relationship between ABAS scores and the number or location of unidentified bright objects. Adaptive functioning deficits are common among children with NF1 and are associated with impairment in other cognitive/behavioral domains, independent of general cognitive ability. Deficits in adaptive behavior are common in children with neurofibromatosis type 1 (NF1). Poor adaptive functioning is associated with impairments in executive function, externalizing behaviors, and attention, regardless of cognitive ability. The presence or location of unidentified bright objects do not predict adaptive behavior skills in children with NF1.

Development and Validation of a MRI-Based Radiomics Prognostic Classifier in Patients with Primary Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most common and deadly type of primary malignant tumor of the central nervous system. Accurate risk stratification is vital for a more personalized approach in GBM management. The purpose of this study is to develop and validate a MRI-based prognostic quantitative radiomics classifier in patients with newly diagnosed GBM and to evaluate whether the classifier allows stratification with improved accuracy over the clinical and qualitative imaging features risk models. Clinical and MR imaging data of 127 GBM patients were obtained from the Cancer Genome Atlas and the Cancer Imaging Archive. Regions of interest corresponding to high signal intensity portions of tumor were drawn on postcontrast T1-weighted imaging (post-T1WI) on the 127 patients (allocated in a 2:1 ratio into a training [n = 85] or validation [n = 42] set), then 3824 radiomics features per patient were extracted. The dimension of these radiomics features were reduced using the minimum redundancy maximum relevance algorithm, then Cox proportional hazard regression model was used to build a radiomics classifier for predicting overall survival (OS). The value of the radiomics classifier beyond clinical (gender, age, Karnofsky performance status, radiation therapy, chemotherapy, and type of resection) and VASARI features for OS was assessed with multivariate Cox proportional hazards model. Time-dependent receiver operating characteristic curve analysis was used to assess the predictive accuracy. A classifier using four post-T1WI-MRI radiomics features built on the training dataset could successfully separate GBM patients into low- or high-risk group with a significantly different OS in training (HR, 6.307 [95% CI, 3.475-11.446]; p < 0.001) and validation set (HR, 3.646 [95% CI, 1.709-7.779]; p < 0.001). The area under receiver operating characteristic curve of radiomics classifier (training, 0.799; validation, 0.815 for 12-month) was higher compared to that of the clinical risk model (Karnofsky performance status, radiation therapy; training, 0.749; validation, 0.670 for 12-month), and none of the qualitative imaging features was associated with OS. The predictive accuracy was further improved when combined the radiomics classifier with clinical data (training, 0.819; validation: 0.851 for 12-month). A classifier using radiomics features allows preoperative prediction of survival and risk stratification of patients with GBM, and it shows improved performance compared to that of clinical and qualitative imaging features models.

MicroRNA-based chemoresistance in glioblastoma

Glioblastoma (GBM) is the most common malignant tumor of the central nervous system in adults. GBM is characterized by violent invasion and poor prognosis. Commonly, there are three main conventional methods to treat GBM, surgery, radiotherapy, and chemotherapy. GBM patients have a median survival ranging from 12 to 15 months, with all tumors developing, at some point, resistance to chemotherapy. There is recently growing interest in the relationship between microRNAs (miRNAs) and chemotherapy resistance in GBM. This paper aims to explore the molecular mechanism, by which miRNAs participate in the formation of chemotherapy resistance in GBM. Here, we summarize the published data relating miRNA to chemotherapy resistance in GBM. We discuss the relationship between mechanisms that miRNA impact upon and provide insight into potential future studies and clinical therapeutics.

Amentoflavone Effectively Blocked the Tumor Progression of Glioblastoma via Suppression of ERK/NF- B Signaling Pathway.

Glioblastoma is the most common primary malignant tumor of the central nervous system, with an annual incidence of 5.26 per 100000 people. The clinical outcome of standard therapy and the survival rate remain poor; therefore, there is an unmet need for a new strategy to treat this lethal disease. Although amentoflavone was known to have anticancer potential in various types of cancers, its antiglioblastoma ability and mechanism remain unrecognized. We demonstrated that amentoflavone may suppress glioblastoma invasion and migration by transwell assay. Moreover, we established NF- B reporter gene system and used that for verifying NF- B inhibition efficacy of amentoflavone on in vitro and in vivo studies. Here, we indicated that amentoflavone not only diminished NF- B activation, but also reduced NF- B-mediated downstream oncogenes expression, such as MMP-2, MMP-9, XIAP, cyclinD1 and VEGF, which was elucidated by Western blot and immunohistochemistry (IHC). Tumor growth inhibition and NF- B reduction was found in the amentoflavone treatment group, which was revealed by the glioblastoma-bearing animal model. In this study, we also used ERK inhibitor and NF- B inhibitor (QNZ) to confirm whether the beneficial result of amentoflavone on glioblastoma was mainly regulated by blockage of ERK/NF- B signaling. In summary, ERK/NF- B signaling pathway has a role in the inhibition of tumor growth by amentoflavone in glioblastoma.

MiR-7-5p suppresses stemness and enhances temozolomide sensitivity of drug-resistant glioblastoma cells by targeting Yin Yang 1

Glioblastoma multiforme (GBM) is the most malignant tumor of the central nervous system, and chemoresistance blunts the effect of temozolomide (TMZ) in the treatment of GBM. Clarifying the underlying mechanism of chemoresistance might yield novel strategies to improve the patients’ response to chemotherapeutics. Mounting evidence indicates that microRNAs (miRNAs) are involved in chemoresistance and tumorigenesis. At present, miR-7-5p has been recognized as a tumor suppressor involved in multiple cancers. However, the biological effects of miR-7-5p in TMZ resistance have not been illuminated. In this study, we used RNA sequencing and high-throughput screening techniques, which revealed that miR-7-5p is significantly downregulated in TMZ resistant LN229 cells (LN229/TMZ-R) compared to control cells (LN229), and low miR-7-5p expression was correlated with recurrence in GBM patients. Ectopic overexpression of miR-7-5p sensitized LN229/TMZ-R cells to TMZ and suppressed the stemness of glioblastoma stem cells (GSCs). Further experiments demonstrated that miR-7-5p exerts its role by directly targeting the 3′-untranslated region of Yin Yang 1 (YY1). Our findings suggest that combinational use of miR-7-5p and TMZ might be a promising therapeutic strategy to increase the long-term drug response in GBM patients.

Inhibitors of ribosome biogenesis repress the growth of MYCN-amplified neuroblastoma

Abnormal increases in nucleolar size and number caused by dysregulation of ribosome biogenesis has emerged as a hallmark in the majority of spontaneous cancers. The observed ribosome hyperactivity can be directly induced by the MYC transcription factors controlling the expression of RNA and protein components of the ribosome. Neuroblastoma, a highly malignant childhood tumor of the sympathetic nervous system, is frequently characterized by MYCN gene amplification and high expression of MYCN and c-MYC signature genes. Here, we show a strong correlation between high-risk disease, MYCN expression, poor survival, and ribosome biogenesis in neuroblastoma patients. Treatment of neuroblastoma cells with quarfloxin or CX-5461, two small molecule inhibitors of RNA polymerase I, suppressed MycN expression, induced DNA damage, and activated p53 followed by cell cycle arrest or apoptosis. CX-5461 repressed the growth of established MYCN-amplified neuroblastoma xenograft tumors in nude mice. These findings suggest that inhibition of ribosome biogenesis represent new therapeutic opportunities for children with high-risk neuroblastomas expressing high levels of Myc.

MicroRNA-195 reverses the resistance to temozolomide through targeting cyclin E1 in glioma cells.

Glioma is the most common malignant tumor of the central nervous system with poor survival. Temozolomide (TMZ) is the first-line chemotherapy drug for initial and recurrent glioma treatment with a relatively good efficacy, which exerts its antitumor effects mainly through cell death induced by DNA double-strand breaks in the G1 and S phases. However, endogenous or acquired resistance to TMZ limits glioma patients’ clinical outcome and is also an important cause of glioma replase. MicroRNA-195 (miR-195) plays an important role in the regulation of G1-phase/S-phase transition, DNA damage repair, and apoptosis of tumor cells. We found that miR-195 expression was significantly decreased in TMZ-resistant glioma cells induced with TMZ and correlated to the resistance index negatively. Also, the exogenous expression of miR-195 reversed TMZ resistance and induced the apoptosis of TMZ-resistant glioblastoma cells. Further bioinformatics analysis showed cyclin E1 (CCNE1) was a potential target gene of miR-195. Knockdown of CCNE1 partially reversed the effect of decreased miR-195 on TMZ resistance. The data from The Cancer Genome Atlas – Cancer Genome further suggested that hsa-miR-195 could negatively regulate the expression of CCNE1 in glioma. In conclusion, miR-195 reverses the resistance to TMZ by targeting CCNE1 in glioma cells and it could act as a potential target for treatment in glioma with TMZ resistance.

RECURRENT GLIOBLASTOMA MANAGEMENT USING STEREOTACTIC RADIOSURGERY AND SYSTEMIC TREATMENT

Glioblastoma multiforme (GBM) is the most common primary malignant tumor of the central nervous system in adults. Dismal survival rates and poor prognosis for recurrent GBM patients still remains a challenging problem. Despite aggressive initial treatment, above 100 % GBM patients have development of recurrent diseases. Management of GBM recurrence is still debatable. The multimodality approaches using combination of stereotactic radiosurgery (SRS), cytostatic agents (Тemozolomide (TMZ)) and antiangiogenic therapy (bevacizumab (BEV)) are often beneficial for such patients and may achieve survival improving. Aim of research: to assess the efficacy and toxicity of combination therapy approach using stereotactic radiosurgery (SRS) and systemic treatment (chemotherapy and antiangiogenic therapy) in glioblastoma multiforme recurrence treatment. Materials and methods: at the State Institution “Institute of Neurosurgery named after acad. A.P. Romodanov of NAMS of Ukraine” (Kyiv, Ukraine) 21 patients (pts) with GBM recurrence were treated (8 females and 11 men; median age at time of diagnosis 52.4 (29.7–69.3) from January 2014 till December 2017. The initial surgical treatment as gross total tumor resection was performed in 12 pts (57.1 %), subtotal resection – 5 pts (23.9 %), biopsy – 4 pts (19 %). 12 pts (57.1 %) were MGMT methylated and 9 pts (42.9 %) were MGMT unmethylated. In all cases adjuvant radiation therapy (60 Gy in 30 fractions) were used, 12 pts of them (57.1 %) – in combination with TMZ followed by 6-12 courses of chemotherapy (TMZ) according Stupp protocol. Recurrent disease was treated by SRS followed by TMZ + BEV. SRS was performed by means of “Trilogy” LINAC (“Varian”, USA) with a median dose and fractions of 19.2 Gy (range, 12.0–36.0) in 1 to 5 fractions. Results: median survival after initial diagnosis was 18.3 months, and 1- and 2-year survival rates of 85.7 % (18 from 21 pts) and 38.1 % (8 from 21 pts) respectively. The median survival from the time of recurrence treatment was 8.3 months. The 6‐ and 12‐months overall survival from SRS were 95.2 % (20 from 21 pts) and 23.8 % (5 from 21 pts), respectively. Adverse radiation effects were noted in 6 (28.6 %) pts and were controlled with corticosteroids. Adverse events grade 1-2 related to the systemic therapy included hematological complications, fatigue, hypertension and proteinuria were observed in 23.8 % (5 from 21 pts) without the occurrence of grade 3 events. Conclusion: recurrent GBM management using combination of SRS, chemotherapy and antiangiogenic therapy is a promising multimodal treatment approach providing survival improving whereas appropriate toxicity ratio. Further studies of combined treatment of GBM relapse are needed.