Effect of Morus alba extract sanggenon C on growth and proliferation of glioblastoma cells / 中国中药杂志

Glioblastoma is the most common primary cranial malignancy, and chemotherapy remains an important tool for its treatment. Sanggenon C(San C), a class of natural flavonoids extracted from Morus plants, is a potential antitumor herbal monomer. In this study, the effect of San C on the growth and proliferation of glioblastoma cells was examined by methyl thiazolyl tetrazolium(MTT) assay and 5-bromodeoxyuridinc(BrdU) labeling assay. The effect of San C on the tumor cell cycle was examined by flow cytometry, and the effect of San C on clone formation and self-renewal ability of tumor cells was examined by soft agar assay. Western blot and bioinformatics analysis were used to investigate the mechanism of the antitumor activity of San C. In the presence of San C, the MTT assay showed that San C significantly inhibited the growth and proliferation of tumor cells in a dose and time-dependent manner. BrdU labeling assay showed that San C significantly attenuated the DNA replication activity in the nucleus of tumor cells. Flow cytometry confirmed that San C blocked the cell cycle of tumor cells in G_0/G_1 phase. The soft agar clone formation assay revealed that San C significantly attenuated the clone formation and self-renewal ability of tumor cells. The gene set enrichment analysis(GSEA) implied that San C inhibited the tumor cell division cycle by affecting the myelocytomatosis viral oncogene(MYC) signaling pathway. Western blot assay revealed that San C inhibited the expression of cyclin through the regulation of the MYC signaling pathway by lysine demethylase 4B(KDM4B), which ultimately inhibited the growth and proliferation of glioblastoma cells and self-renewal. In conclusion, San C exhibits the potential antitumor activity by targeting the KDM4B-MYC axis to inhibit glioblastoma cell growth, proliferation, and self-renewal.

The action mechanism of glioblastoma cell-derived exosome: a review / 生物工程学报

Patients with glioblastoma (GBM) generally have a bad prognosis and short overall survival after being treated with surgery, chemotherapy or radiotherapy due to the histological heterogeneity, strong invasive ability and rapid postoperative recurrence of GBM. The components of GBM cell-derived exosome (GBM-exo) can regulate the proliferation and migration of GBM cell via cytokines, miRNAs, DNA molecules and proteins, promote the angiogenesis via angiogenic proteins and non-coding RNAs, mediate tumor immune evasion by targeting immune checkpoints with regulatory factors, proteins and drugs, and reduce drug resistance of GBM cells through non-coding RNAs. GBM-exo is expected to be an important target for the personalized treatment of GBM and a marker for diagnosis and prognosis of this kind of disease. This review summarizes the preparation methods, biological characteristics, functions and molecular mechanisms of GBM-exo on cell proliferation, angiogenesis, immune evasion and drug resistance of GBM to facilitate developing new strategies for the diagnosis and treatment of GBM.

Genomic and transcriptomic characterization of the human glioblastoma cell line AHOL1

Cancer cell lines are widely used as in vitro models of tumorigenesis, facilitating fundamental discoveries in cancer biology and translational medicine. Currently, there are few options for glioblastoma (GBM) treatment and limited in vitro models with accurate genomic and transcriptomic characterization. Here, a detailed characterization of a new GBM cell line, namely AHOL1, was conducted in order to fully characterize its molecular composition based on its karyotype, copy number alteration (CNA), and transcriptome profiling, followed by the validation of key elements associated with GBM tumorigenesis. Large numbers of CNAs and differentially expressed genes (DEGs) were identified. CNAs were distributed throughout the genome, including gains at Xq11.1-q28, Xp22.33-p11.1, Xq21.1-q21.33, 4p15.1-p14, 8q23.2-q23.3 and losses at Yq11.21-q12, Yp11.31-p11.2, and 15q11.1-q11.2 positions. Nine druggable genes were identified, including HCRTR2, ETV1, PTPRD, PRKX, STS, RPS6KA6, ZFY, USP9Y, and KDM5D. By integrating DEGs and CNAs, we identified 57 overlapping genes enriched in fourteen pathways. Altered expression of several cancer-related candidates found in the DEGs-CNA dataset was confirmed by RT-qPCR. Taken together, this first comprehensive genomic and transcriptomic landscape of AHOL1 provides unique resources for further studies and identifies several druggable targets that may be useful for therapeutics and biologic and molecular investigation of GBM.

Effects of tetrandrine on proliferation, migration, and invasion of glioblastoma cells / 中国中药杂志

Glioblastoma is the most common intracranial primary malignant tumor, which leads to the poor quality of life of patients and has a high recurrence rate. Chemotherapy is a vital part in the treatment of this disease. Tetrandrine(Tet) is an active ingredient extracted from the root of the Chinese medicinal plant Stephania tetrandra, which has been proved with a wide range of pharmacological effects including anti-tumor. However, there are few studies regarding the effect of Tet on glioma. In this study, MTT and BrdU assays were employed to detect the effect of Tet on the proliferation of LN229 glioblastoma cells; flow cytometry was used to analyze the cycle distribution and apoptosis; plate cloning assay and soft agar colony formation assay were performed to study the colony formation ability of LN229 cells exposed to Tet; scratch assay and Transwell assay were conducted to detect the ability of migration and invasion; Western blot was adopted to the exploration of the molecular mechanism. The MTT and BrdU assays showed that Tet inhibited the proliferation of LN229 cells in a time-and dose-dependent manner. The plate cloning assay and soft agar colony formation assay showed that Tet weakened the colony formation of LN229 cells in vitro; cytometry assay showed that Tet blocked cells in the G_1 phase and promoted cell apoptosis; scratch and Transwell assays proved that Tet inhibited the migration and invasion of LN229 cells; Western blot results showed that Tet down-regulated the expression levels of CDK2, CDK6, cyclin D1, cyclin E1, snail, slug, vimentin, and N-cadherin, while up-regulated the level of E-cadherin. The results indicate that Tet has a certain inhibitory effect on the proliferation, migration, and invasion of LN229 glioblastoma cells, and such effect may be related to the participation of Tet in the regulation of c-Myc/p27 axis and snail signaling pathway.

Overexpression of lncRNA MEG3 inhibits proliferation and invasion of glioblastoma U251 cells / 南方医科大学学报

OBJECTIVE@#To investigate the effects of overexpression of long noncoding RNA (lncRNA) MEG3 on the proliferation and invasion of glioblastoma U251 cells by suppressing the expression of hypoxia inducible factor 1@*METHODS@#The expression of lncRNA MEG3 and HIF1@*RESULTS@#The expression of MEG3 was significantly lower and HIF1@*CONCLUSIONS@#MEG3 overexpression inhibits the proliferation and invasion of U251 cells through suppressing the expression of HIF1

A comprehensive analysis of the angiogenesis-related genes in glioblastoma multiforme vs. brain lower grade glioma / Uma análise abrangente dos genes relacionados à angiogênese no glioblastoma multiforme vs. glioma cerebral de baixo grau

Abstract Brain tumors are one of the most common causes of cancer-related deaths around the world. Angiogenesis is critical in high-grade malignant gliomas, such as glioblastoma multiforme. Objective: The aim of this study is to comparatively analyze the angiogenesis-related genes, namely VEGFA, VEGFB, KDR, CXCL8, CXCR1 and CXCR2 in LGG vs. GBM to identify molecular distinctions using datasets available on The Cancer Genome Atlas (TCGA). Methods: DNA sequencing and mRNA expression data for 514 brain lower grade glioma (LGG) and 592 glioblastoma multiforme (GBM) patients were acquired from The Cancer Genome Atlas (TCGA), and the genetic alterations and expression levels of the selected genes were analyzed. Results: We identified six distinct KDR mutations in the LGG patients and 18 distinct KDR mutations in the GBM patients, including missense and nonsense mutations, frame shift deletion and altered splice region. Furthermore, VEGFA and CXCL8 were significantly overexpressed within GBM patients. Conclusions: VEGFA and CXCL8 are important factors for angiogenesis, which are suggested to have significant roles during tumorigenesis. Our results provide further evidence that VEGFA and CXCL8 could induce angiogenesis and promote LGG to progress into GBM. These findings could be useful in developing novel targeted therapeutics approaches in the future.

Resumo Os tumores cerebrais são uma das causas mais comuns de mortes relacionadas ao câncer em todo o mundo. A angiogênese tem caráter crítico em gliomas malignos de alto grau, como o glioblastoma multiforme. Objetivo: O objetivo deste estudo foi analisar comparativamente os genes relacionados à angiogênese, VEGFA, VEGFB, KDR, CXCL8, CXCR1 e CXCR2 em GBG vs. GBM para identificar distinções moleculares usando conjuntos de dados disponíveis no The Cancer Genome Atlas (TCGA). Métodos: Os dados de sequenciamento de DNA e expressão de mRNA para 514 pacientes com glioma cerebral de baixo grau (GBG) e 592 pacientes com glioblastoma multiforme (GBM) foram adquiridos do TCGA e as alterações genéticas e os níveis de expressão dos genes selecionados foram analisados. Resultados: Identificamos seis mutações KDR distintas nos pacientes GBG e 18 mutações KDR distintas nos pacientes GBM, incluindo mutações missense e nonsense, exclusão de mudança de quadro e região de emenda alterada. Além disso, VEGFA e CXCL8 foram significativamente super-expressos nos pacientes com GBM. Conclusões: VEGFA e CXCL8 são fatores importantes para a angiogênese, os quais parecem ter um papel significativo durante a tumorigênese. Nossos resultados fornecem evidências adicionais de que o VEGFA e o CXCL8 podem induzir a angiogênese e promover o GBG a progredir no GBM. Esses achados podem ser úteis no desenvolvimento de novas abordagens terapêuticas direcionadas no futuro.

Astrocyte elevated gene-1 serves as a target of miR542 to promote glioblastoma proliferation and invasion / 中华医学杂志(英文版)

BACKGROUND@#Epithelial to mesenchymal transition (EMT) is strongly linked with tumor invasion and metastasis, which performs a vital role in carcinogenesis and cancer progression. Emerging evidence suggests that microRNAs (miRNAs) expression are closely associated to EMT by regulating targeted genes. MiR542 has been found to be involved in the EMT program and bound up with various cancers. However, the functions of miR542 and its underlying mechanism in glioblastoma multiforme (GBM) remain largely unknown. In the current study, we investigated the effect of astrocyte elevated gene-1 (AEG-1) on U251 cells aggressiveness, proliferation, apoptosis, and cell cycle.@*METHODS@#The screening of targeted miRNAs was performed, as well as the functional roles and mechanisms of miR542 were explored.@*RESULTS@#MiR542 was selected as the target because of the most significantly differential expression and this high level of expression negatively correlated with cell migration and proliferation, which suggested that miR542 could be a novel tumor suppressor. Moreover, we confirmed that AEG-1 was a direct targeted gene of miR542 by luciferase activity assay, reverse transcription-polymerase chain reaction, and immunoblotting analysis. Furthermore, miR542 suppressed the expression of AEG-1, which upgraded the level of E-cadherin and degraded Vimentin expression contributing to retraining EMT.@*CONCLUSION@#The in vitro findings demonstrated that miR542 inhibited the migration and proliferation of U251 cells and suppressed EMT through targeting AEG-1, indicating that miR542 may be a potential anti-cancer target for GBM.

Citometría de flujo en reticulocitos de sangre periférica como indicador de inestabilidad cromosómica en pacientes con gliomas de alto grado / Flow cytometry in peripheral blood reticulocytes as a marker of chromosome instability in highgrade glioma patients

Resumen Introducción. La cuantificación de la inestabilidad cromosómica es un parámetro importante para evaluar la genotoxicidad y la radiosensibilidad. Las técnicas convencionales requieren cultivos celulares o laboriosos análisis microscópicos de cromosomas o núcleos. La citometría de flujo en reticulocitos ha surgido como una alternativa para los estudios in vivo, ya que reduce los tiempos de análisis e incrementa hasta en 20 veces el número de células analizables. Objetivos. Estandarizar los parámetros de citometría de flujo requeridos para seleccionar y cuantificar reticulocitos micronucleados (RET-MN) a partir de muestras de sangre periférica, y cuantificar la frecuencia de esta subpoblación anormal como medida de inestabilidad citogenética en sendas poblaciones de voluntarios sanos (n=25) y pacientes (n=25) recién diagnosticados con gliomas de alto grado antes de iniciar el tratamiento. Materiales y métodos. Las células sanguíneas se marcaron con anti-CD71-PE para reticulocitos, anti- CD61-FITC para la exclusión de plaquetas y yoduro de propidio para detectar el ADN en reticulocitos. La fracción celular MN-RETCD71+ se seleccionó y se cuantificó con un citómetro de flujo automático. Resultados. Se describió detalladamente la estandarización de los parámetros citométricos, con énfasis en la selección y la cuantificación de la subpoblación celular MN-RETCD71+. Se establecieron los niveles basales de MN-RETCD71+ en la población de control y en los pacientes se encontró un incremento de 5,2 veces antes de iniciar el tratamiento (p<0,05). Conclusión. Los resultados evidenciaron la utilidad de la citometría de flujo acoplada a la marcación de las células RETCD71+ como método eficiente para cuantificar la inestabilidad cromosómica in vivo. Se sugieren posibles razones del incremento de micronúcleos en células RETCD71+ de pacientes con gliomas.

Abstract Introduction: The quantification of chromosomal instability is an important parameter to assess genotoxicity and radiosensitivity. Most conventional techniques require cell cultures or laborious microscopic analyses of chromosomes or nuclei. However, a flow cytometry that selects the reticulocytes has been developed as an alternative for in vivo studies, which expedites the analytical procedures and increases up to 20 times the number of target cells to be analyzed. Objectives: To standardize the flow cytometry parameters for selecting and quantifying the micronucleated reticulocytesCD71+ (MN-RET) from freshly drawn peripheral blood and to quantify the frequency of this abnormal cell subpopulation as a measure of cytogenetic instability in populations of healthy volunteers (n =25), and patients (n=25), recently diagnosed with high-grade gliomas before the onset of treatment. Materials and methods: Blood cells were methanol-fixed and labeled with anti-CD-71-PE for reticulocytes, antiCD-61-FITC for platelet exclusion, and propidium iodide for DNA detection in reticulocytes. The MN-RETCD71+ cell fraction was selected and quantified with an automatic flow cytometer. Results: The standardization of cytometry parameters was described in detail, emphasizing the selection and quantification of the MN-RETCD71+ cellular fraction. The micronuclei basal level was established in healthy controls. In patients, a 5.2-fold increase before the onset of treatment was observed (p <0.05). Conclusion: The data showed the usefulness of flow cytometry coupled with anti-CD-71-PE and anti- CD-61-FITC labeling in circulating reticulocytes as an efficient and high resolution method to quantify chromosome instability in vivo. Finally, possible reasons for the higher average of micronuclei in RETCD71+ cells from untreated high-grade glioma patients were discussed.

Expresión de O6-metilguanina-ADN-metiltransferasa (MGMT) en pacientes chilenos con glioblastoma multiforme / O6-methylguanine-DNA-methyltransferase (MGMT) expression in patients with glioblastoma multiforme

Background: Patients with Glioblastoma multiforme (GBM) have a five years survival of less than 5%, but the response to chemotherapy with alkylating agents can vary depending on the methylation status of O6-methylguanine-DNA-methyltransferase (MGMT). Genetic testing has limitations for routine use, while immunohistochemistry (IHC) offers a fast and affordable technique but with heterogeneous results in the literature. Aim: To evaluate MGMT expression by IHC in tumor tissue of Chilean patients with GBM. Material and Methods: Tumor samples of 29 patients with a pathological diagnosis of GBM were studied. We performed IHC staining and manual analysis of positive and negative cells for MGMT expression. A cut-off of at least 10% of cells expressing MGMT was used. Demographic and clinical features of patients were obtained from clinical records. Results: The median number of cells counted per case was 692 (interquartile range [IQR] 492-928). Fifteen cases (52%) were positive for MGMT expression. Median overall survival was 5.3 months (IQR 3.4-12-8). The effect of MGMT expression on the therapeutic response was not studied since only 3 patients received chemotherapy. Conclusions: Our results are similar to international reports, but we were not able to determine the association between MGMT expression and therapeutic response.

The effect of downregulation of Stathmin gene on biological behaviors of U373 and U87-MG glioblastoma cells

BACKGROUND: Stathmin as a critical protein involved in microtubule polymerization, is necessary for survival of cancer cells. However, extremely little is known about Stathmin in glioblastoma. So, this study was designed to elucidate the function of Stathmin gene in the tumorigenesis and progression of glioblastoma cells. METHOD: The lentiviral interference vector pLV3-si-Stathmin targeting Stathmin gene and the control vector pLV3-NC were established for the co-transfection of 293T cells together with the helper plasmids. Viral titer was determined via limiting dilution assay. Then pLV3-si-Stathmin and pLV3-NC were stably co-transfected into U373 and U87-MG glioblastoma cells. Expression levels of Stathmin protein in each group were determined by using Western Blot, and the proliferation and migration ability of the cells with downregulated Stathmin were evaluated through CCK8 assay and transwell invasion assay, respectively. Cell cycles and cell apoptosis were detected with flow cytometry. Finally, the effect of Stathmin in tumor formation was determined in nude mice. RESULT: DNA sequencing and viral titer assay indicated that the lentiviral interference vector was successfully established with a viral titer of 4 × 108 TU/ml. According to the results from Western Blotting, Stathmin protein expression level decreased significantly in the U373 and U87-MG cells after transfected with pLV3-si-Stathmin, respectively, compared with those transfected with pLV3-NC. In glioblastoma cells, the cell proliferation and migration were greatly inhibited after the downregulation of Stathmin protein. Flow cytometry showed that much more cells were arrested in G2/M phasein Stathmin downregulated group, compared with the non-transfection group and NC group. But Stathmin downregulation did not induce significant cell apoptosis. Tumor formation assay in nude mice showed that tumor formation was delayed after Stathmin downregulation, with a reduction in both tumor formation rate and tumor growth velocity. CONCLUSION: Stathmin downregulation affected the biological behaviors of U373 and U87-MG glioblastoma cells, inhibiting the proliferation and migration of tumor cells. Stathmin gene may serve as a potential target in gene therapy for glioblastoma.

High expression of XIAP and Bcl-2 may inhibit programmed cell death in glioblastomas / Alta expressão de XIAP e Bcl-2 pode inibir morte celular programada em glioblastomas

ABSTRACT Glioblastoma (GBM) is the most malignant glioma and represents 29% of all brain tumors. Tumorigenesis is intimately connected with characteristics acquired in the physiologic pathway of cellular death. Objective: In the present study, the expression of anti-apoptotic (XIAP and Bcl-2) and apoptotic (cytochrome C, caspase 9, APAF-1), caspase 3 and the Smac/DIABLO genes related to the apoptosis pathway were evaluated in 30 samples of glioblastoma. Methods: The gene expression was evaluated in 30 glioblastomas (WHO grade IV) and compared to 10 white matter control samples with real-time PCR. Results and Conclusion: There were higher expressions of XIAP (p = 0.0032) and Bcl-2 (p = 0.0351) in the glioblastoma samples compared to the control samples of normal brain. These results raise the question of whether Bcl-2 and XIAP genes can be responsible for the inhibition of programmed cell death in glioblastomas. Moreover, they provide additional information capable of allowing the development of new target therapy strategies.

RESUMO O glioblastoma (GBM) é o glioma mais maligno e representa 29% de todos os tumores cerebrais. A tumorigênese está intimamente ligada à características adquiridas na via fisiológica de morte celular. Objetivo: Avaliar a expressão de genes anti-apoptóticos (XIAP e Bcl-2) e apoptóticos (citocromo C, a caspase 9, APAF-1), caspase 3 e SMAC/DIABLO, relacionados à apoptose, em 30 amostras de tecido de pacientes com glioblastoma. Métodos: A expressão gênica foi avaliada em trinta glioblastomas e comparada a dez amostras controles de substância branca por PCR em tempo real. Resultados e Conclusão: Houve maior nível de expressão de XIAP (p = 0,0032) e Bcl-2 (p = 0,0351) em comparação com as amostras controle, de cérebro normal. Estes resultados levantam a questão de que os genes Bcl-2 e XIAP podem ser responsáveis pela inibição da morte celular programada em glioblastomas, além disso, proporcionam informação adicional capaz de permitir o desenvolvimento de novas estratégias de terapia alvo.

Galectin-8 promotes migration and proliferation and prevents apoptosis in U87 glioblastoma cells

BACKGROUND: Glioblastoma is one of the most aggressive cancers of the brain. Malignant traits of glioblastoma cells include elevated migration, proliferation and survival capabilities. Galectins are unconventionally secreted glycan-binding proteins that modulate processes of cell adhesion, migration, proliferation and apoptosis by interacting with beta-galactosides of cell surface glycoproteins and the extracellular matrix. Galectin-8 is one of the galectins highly expressed in glioblastoma cells. It has a unique selectivity for terminally sialylated glycans recently found enhanced in these highly malignant cells. A previous study in glioblastoma cell lines reported that Gal-8 coating a plastic surface stimulates two-dimensional motility. Because in other cells Gal-8 arrests proliferation and induces apoptosis, here we extend its study by analyzing all of these processes in a U87 glioblastoma cell mode.l METHODS: We used immunoblot and RT-PCR for Gal-8 expression analysis, recombinant Gal-8 produced in a bacteria system for Gal-8 treatment of the cells, and shRNA in lentivirus transduction for Gal-8 silencing. Cell migration as assessed in transwell filters. Cell proliferation, cell cycle and apoptosis were analyzed by FACS. RESULTS: Gal-8 as a soluble stimulus triggered chemotactic migration of U87 cells across the polycarbonate filter of transwell chambers, almost as intensively as fetal bovine serum. Unexpectedly, Gal-8 also enhanced U87 cell growth. Co-incubation of Gal-8 with lactose, which blocks galectin-glycan interactions, abrogated both effects. Immunoblot showed Gal-8 in conditioned media reflecting its secretion. U87 cells transduced with silencing shRNA in a lentiviral vector expressed and secreted 30-40 % of their normal Gal-8 levels. These cells maintained their migratory capabilities, but decreased their proliferation rate and underwent higher levels of apoptosis, as revealed by flow cytometry analysis of cell cycle, CFSE and activated caspase-3 staining. Proliferation seemed to be more sensitive than migration to Gal-8 expression levels. CONCLUSIONS: Gal-8, either secreted or exogenously enriched in the media, and acting through extracellular glycan interactions, constitutes a strong stimulus of directional migration in glioblastoma U87 cells and for the first time emerges as a factor that promotes proliferation and prevents apoptosis in cancerous cells. These properties could potentially contribute to the exaggerated malignancy of glioblastoma cells.

P53 expression in glioma: an immunohistochemical study

The aim of this study was to evaluate the frequency of immunohistochemical [IHC] expression of p53 protein in different types of glioma in Mosul city, and to correlate p53 expression with the histological types and grades of gliomas, and compare the results of this study with those of others. This study was performed on 50 cases of glioma. Samples were obtained in a prospective and retrospective fashion [cross-sectional study]. The samples were collected during the period extending from October 2010 to May 2011. All cases were obtained from Al-Jamhuri Teaching Hospital in Mosul city, Northen Iraq and some private laboratories. Typing and grading of the glioma were done according to World Health Organization [WHO] classification system. P53 expression was assessed immunohistochemically. Fifty cases of gliomas were collected; they included 37 cases of astrocytoms, 8 ependymoma 4 oligodendrogliomas and 1 oligoastrocytoma. p53 expression was detected in 25 cases ofglioma [50%]. The positive cases included 59.45% ofastrocytomas, 50% of oligodendrogliomas, and one case of oligoastrocytoma which was positive also. On the other hand, all of the ependymomas were negative for p53 protein. p53 was significantly related to the grades of glioma, but not significantly related to the type ofglioma. P53 expression was expressed in 50% of gliomas in Mosul city. P53 expression is common among high grade astrocytomas and mixed gliomas, less among oligodendrogliomas, and lacking in cases of ependymomas. Statistically, p53 expression was not significantly correlated with the type of glioma. p53 index is directly correlated with the grade of glioma, and so it is of prognostic value

Glioblastoma: approach to treat elderly patients / Glioblastoma: enfoque no tratamento de pacientes idosos

Treating elderly cancer patients is a challenge for oncologists, especially considering the several therapeutic modalities in glioblastoma. Extensive tumor resection offers the best chance of local control. Adequate radiotherapy should always be given to elderly patients if they have undergone gross total resection and have maintained a good performance status. Rather than being ruled out, chemotherapy should be considered, and temozolomide is the chosen drug. A comprehensive geriatric assessment is a valuable tool to help guiding treatment decisions in elderly patients with glioblastoma.

O tratamento de idosos com câncer é um desafio para a prática oncológica, especialmente no que se refere à terapêutica multimodal do glioblastoma. Nessa população, a ressecção ampla do tumor oferece a melhor chance de controle local e, naqueles pacientes que mantenham um bom performance status, a radioterapia complementar deve sempre ser levada em consideração. A quimioterapia também tem um papel no tratamento, sendo a temozolomida a droga de eleição. Frente à heterogeneidade desses pacientes, uma avaliação geriátrica ampla é um instrumento valioso no auxílio da decisão terapêutica em idosos com glioblastoma.

Correlation of MGMT promoter methylation status with gene and protein expression levels in glioblastoma

OBJECTIVES: 1) To correlate the methylation status of the O6-methylguanine-DNA-methyltransferase (MGMT) promoter to its gene and protein expression levels in glioblastoma and 2) to determine the most reliable method for using MGMT to predict the response to adjuvant therapy in patients with glioblastoma. BACKGROUND: The MGMT gene is epigenetically silenced by promoter hypermethylation in gliomas, and this modification has emerged as a relevant predictor of therapeutic response. METHODS: Fifty-one cases of glioblastoma were analyzed for MGMT promoter methylation by methylation-specific PCR and pyrosequencing, gene expression by real time polymerase chain reaction, and protein expression by immunohistochemistry. RESULTS: MGMT promoter methylation was found in 43.1 percent of glioblastoma by methylation-specific PCR and 38.8 percent by pyrosequencing. A low level of MGMT gene expression was correlated with positive MGMT promoter methylation (p = 0.001). However, no correlation was found between promoter methylation and MGMT protein expression (p = 0.297). The mean survival time of glioblastoma patients submitted to adjuvant therapy was significantly higher among patients with MGMT promoter methylation (log rank = 0.025 by methylation-specific PCR and 0.004 by pyrosequencing), and methylation was an independent predictive factor that was associated with improved prognosis by multivariate analysis. DISCUSSION AND CONCLUSION: MGMT promoter methylation status was a more reliable predictor of susceptibility to adjuvant therapy and prognosis of glioblastoma than were MGMT protein or gene expression levels. Methylation-specific polymerase chain reaction and pyrosequencing methods were both sensitive methods for determining MGMT promoter methylation status using DNA extracted from frozen tissue.

Cytogenetic Characterizations of Central Nervous System Tumors: The First Comprehensive Report from a Single Institution in Korea

The World Health Organization (WHO) classification of central nervous system (CNS) tumors incorporates morphology, cytogenetics, molecular genetics, and immunologic markers. Despite the relatively large number of CNS tumors with clonal chromosome abnormalities, only few studies have investigated cytogenetic abnormalities for CNS tumors in Korea. Thus, we investigated 119 CNS tumors by conventional G-banded karyotypes to characterize patterns of chromosomal abnormalities involving various CNS tumors, and 92.4% of them were cultured and karyotyped successfully. Totally, 51.8% of karyotypable CNS tumors showed abnormal cytogenetic results, including neuroepithelial tumors (75.0%), meningeal tumors (71.1%), pituitary adenomas (4.2%), schwannomas (44.4%), and metastatic tumors (100.0%). Glioblastomas had hyperdiploid, complex karyotypes, mainly involving chromosomes Y, 1, 2, 6, 7, 10, 12, 13, and 14. Monosomy 22 was observed in 56.4% of meningiomas. There was a significant increase in the frequencies of karyotypic complexity according to the increase of WHO grade between grades I and II (P=0.0422) or IV (P=0.0101). Abnormal karyotypes were more complex at high-grade tumors, suggesting that the karyotype reflects the biologic nature of the tumor. More detailed cytogenetic and molecular characterizations of CNS tumors contribute to better diagnostic criteria and deeper insights of tumorigenesis, eventually resulting in development of novel therapeutic strategies.

Cytogenetic Characterizations of Central Nervous System Tumors: The First Comprehensive Report from a Single Institution in Korea

The World Health Organization (WHO) classification of central nervous system (CNS) tumors incorporates morphology, cytogenetics, molecular genetics, and immunologic markers. Despite the relatively large number of CNS tumors with clonal chromosome abnormalities, only few studies have investigated cytogenetic abnormalities for CNS tumors in Korea. Thus, we investigated 119 CNS tumors by conventional G-banded karyotypes to characterize patterns of chromosomal abnormalities involving various CNS tumors, and 92.4% of them were cultured and karyotyped successfully. Totally, 51.8% of karyotypable CNS tumors showed abnormal cytogenetic results, including neuroepithelial tumors (75.0%), meningeal tumors (71.1%), pituitary adenomas (4.2%), schwannomas (44.4%), and metastatic tumors (100.0%). Glioblastomas had hyperdiploid, complex karyotypes, mainly involving chromosomes Y, 1, 2, 6, 7, 10, 12, 13, and 14. Monosomy 22 was observed in 56.4% of meningiomas. There was a significant increase in the frequencies of karyotypic complexity according to the increase of WHO grade between grades I and II (P=0.0422) or IV (P=0.0101). Abnormal karyotypes were more complex at high-grade tumors, suggesting that the karyotype reflects the biologic nature of the tumor. More detailed cytogenetic and molecular characterizations of CNS tumors contribute to better diagnostic criteria and deeper insights of tumorigenesis, eventually resulting in development of novel therapeutic strategies.