Gliomas são os tumores mais comuns no SNC, apresentando altas taxas de invasibilidade e proliferação, resistência à quimio e radioterapias, e elevados índices de recorrência e morte. As células-tronco tumorais constituem uma minoria dentre as células do tumor, apresentam características de células tronco neurais podendo sofrer diferenciação e auto-renovação. Linhagens celulares de gliomas, como U87, são capazes de produzir tumoresferas quando em alta confluência, que são similares às neuroesferas produzidas por células tronco neurais, e são ricas em células tronco tumorais (CSCs). Em gliomas, CSCs podem ser identificadas por expressarem o marcador de superfície CD133. Receptores purinérgicos estão envolvidos em diversos processos biológicos. O ATP induz respostas celulares como proliferação e diferenciação, e a degradação deste nucleotídeo por células de glioma é lenta, o que resulta no seu acúmulo no espaço extracelular. O objetivo deste trabalho é identificar a população de CSCs em U87 bem como o efeito do ATP na formação de esferas, expressão do marcador CD133, a expressão de genes de receptores purinérgicos e de genes marcadores de células diferenciadas (GLAST e CAMKII) e de células indiferenciadas (CD133 e OCT-4). U87 foram mantidas em condições padrão com 5% de SFB e esferas foram obtidas através de crescimento sobre ágar 1%. RNA total foi extraído de esferas e monocamada, e os genes de interesse foram amplificados em reação de RT-PCR com primers específicos. Esferas apresentam uma maior expressão de CD133, visto por citometria e imunodetecção. O mRNA de OCT-4 também foi mais expresso em esferas do que em monocamada, que expressa mais CAMKII e GLAST. ATP em uma concentração final de 100 µM reduz significativamente o número de esferas formadas (P<0.05) durante um período de 7 dias e também reduz a expressão de CD133. Dentre os receptores purinérgicos, a expressão de P2X4 foi maior em esferas, e P2X6 em monocamada. Estes resultados indicam que as esferas possuem componentes de células tronco e que a sinalização purinérgica pode estar envolvida em importantes aspectos da biologia de CSCs. / Glioblastoma multiformes are the most aggressive tumors in the CNS and are characterized by high invasion and proliferation rates, as well as for being resistant to chemo and radiotherapies. This leads to one of the worst prognosis among cancers. Cancer stem cells (CSCs) are scarce among the tumor cells, but can undergo differentiation and self-renewal, being fundamental for tumor maintenance. Tumorspheres, which resemble neurospheres, can grow in glioma cell cultures and are rich in CSC. Additionally, CSCs seem to be more resistant to radiotherapy and strategies aimed at differentiating these stem cells have potential to produce less aggressive and more efficient treatment regimes. CSCs have been identified in different tumor types as well as in established cell lines such as the human glioma cell line U87, and are characterized by the presence of the CD133 glycoprotein. Purinergic receptors are stimulated by nucleotides and nucleosides, and are involved in many biological processes, including embryonic development. ATP induces several cellular responses, such as proliferation and differentiation, and it has been demonstrated that the degradation of this nucleotide is slow in glioma cells, which results in its accumulation in the extracellular space. The aim of this work was to characterize the CSC population in U87 and the effect of ATP in sphere formation. Spheres were obtained by plating cells on a thin layer of agar. Tumorspheres presented a higher amount of CD133 marker as analyzed by flow citometry and western blotting. mRNA expression of OCT-4, a marker of undifferentiated cells, was higher in spheres, while GLAST and CAMKII, markers of differentiated glial and neuronal cells respectively, presented higher expression in the monolayer cells. Cells plated in the presence of ATP 100 µM formed 54% less spheres (P<0.05) when compared to control and also had a reduced level of CD133 marker. Among the purinergic receptors, P2X4 expression was higher in spheres, whereas P2X6 expression was higher in the monolayer. Our results indicate that spheres have components of stem cells and that the purinergic signaling is involved in important aspects of CSC biology.

The purinergic P2X7 receptor (P2X7R) is an ionotropic adenosine triphosphate(ATP) receptor which is closely linked with pathological conditions in the central nervous system (CNS). Gliomas are the most common primary brain tumors with presently no cures. The roles of the P2X7R in these diseases have not been previously studied and in this work, I have used the rat C6 glioma as an experimental model system to investigate expression and function of the P2X7R in vitro and in vivo. The in vitro study has examined expression of the P2X7R in C6 cells and the involvement of this receptor in mediating cell functional responses. C6 glioma cells were found to express the P2X7R at both mRNA and protein levels. The P2X7Ragonist, 2', 3 '-(benzoy1-4-benzoy1)-ATP (BzATP) induced an increase in intracellularCa2+ concentration, an effect which was largely inhibited by periodate-oxidized ATP(OxATP), an irreversible P2X7R antagonist. BzATP treatment of C6 cells also resulted in ethidium bromide dye uptake indicating pore formation was induced byP2X7R activation. Chronic exposure of C6 cells to BzATP showed up-regulation of several pro-inflammatory factors including the chemokines monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) and the angiogenic factor vascular endothelial growth factor (VEGF) suggesting the P2X7R in C6 cells is involved in mediating inflammation in tumors. In addition, BzATP treatment was found to enhance wound-induced cell migration, an effect which was inhibited in the presence of OxATP, or another P2X7R antagonist, Brilliant Blue G (BBG). The in vivo study examined whether pharmacological modulation of P2X7R with BBG altered tumor growth. C6 glioma cells were implanted into the striatum of rat brain and in situ P2X7R expression was shown to be associated with glioma cells and resident microglia. Preliminary results have indicated that inhibition of P2X7R leads to a reduced volume of brain tumors formed by transplanted C6 cells. The overall results from this study demonstrate the novel finding that C6 glioma cells express functional P2X7R and suggest pharmacological modulation of theP2X7R could serve as an effective strategy to inhibit the development and progression of brain tumors. / Medicine, Faculty of / Anesthesiology, Pharmacology and Therapeutics, Department of / Graduate

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Background: Malignant cerebral glioma is a rare cancer but has a devastating impact on patients and their families. In Scotland each year, around 450 people are diagnosed with glioma. Prognosis is generally poor and treatment is essentially palliative. There is a growing recognition that non-clinical aspects of care for both patients and their families need to be acknowledged and integrated into health care provision in line with a patient-focused ethos of care. Currently, there is relatively little research exploring the psychosocial issues and needs of this patient group. Aims: To give patients being investigated for malignant cerebral glioma and their families the opportunity to describe their shared experiences of their illness journey and voice their concerns and unmet needs. To examine how these experiences and needs change over time as the patient progresses through the illness journey. To ascertain the extent to which these needs are recognised and supported, taking into accounts professionals’ views and making suggestions for steps forward in improving patients’ psychosocial care. Methods: A total of 80 qualitative prospective longitudinal interviews (30 paired and 50 separate) were conducted with 26 people with a suspected or confirmed diagnosis of malignant cerebral glioma being treated at a regional hospital and 24 primary relative/informal carers. Patients and carers were interviewed at the following five times: leading up to diagnosis; following a formal diagnosis; around the end of initial treatment (radiotherapy); at a designated six-month follow-up stage; and bereavement interviews with carers. One-off interviews were carried out with 66 health professionals (19 case-linked GPs and 47 other health, health-related and social care professionals involved in patients' care). Interviews were recorded and transcribed verbatim and analysed using the constant comparative method from a grounded theory approach assisted by QSR NVivo Version 7. Findings: Distress, anxiety and shock were overwhelming reactions in the period leading up to a diagnosis of glioma, making it difficult for participants to make sense of their experience. Over time, participants employed a range of strategies in order to cope with their diagnosis. Social and emotional support from professionals and friends, family and other patients were vital in many cases but support often felt inadequate. The role of information and the manner in which it was communicated was closely linked to participants’ ability to cope. Information needs were variable but on the whole patients and carers did not feel well informed. Dealing with cognitive and physical symptoms of their illness and side effects of treatment inhibited patients’ ability to resume their everyday activities. The lives of relatives were also affected as they struggled to care for their loved ones. People with a diagnosis of glioma were faced with the possibility of death from an early point in their illness trajectory and awareness of this, coupled with ability to make sense of existential issues, varied across participants. Issues around support, communication, information and palliative care were considered to be important among health professionals involved in the care of people with a diagnosis of glioma but provision fell short. Conclusions: Concerns regarding information, communication and support reported elsewhere in the literature are enduring in glioma patients and their relatives. Reporting of unmet psychosocial and supportive care issues by patients and recognition by professionals of the need to improve these dimensions of care for people affected by glioma emphasises previous recommendations yet to be fully implemented into patient care.

Diffuse gliomas, the most common primary brain cancer, are classified into astrocytomas, oligodendrogliomas and oligoastrocytomas according to morphological similarity to glial cell, and categorized into grade II to IV according to histological features. While standard-of-care of surgery followed by chemo-radiotherapy exists for grade IV glioblastomas, lower grade gliomas (grades II and III) remain as a heterogeneous entity with variable treatment and outcome. The current WHO classification of lower grade glioma is purely based on histology and subject to interobserver variation, which can be aggravated by sampling error or small tissue biopsy. Objective prognostic biomarker guiding patient risk stratification is also relatively inadequate in lower grade gliomas. Since molecular markers will be supplemented into the future classification system of gliomas in order to facilitate clinico-pathological prediction and therapeutic planning in patient management and clinical trials, identification of clinically relevant biomarker is of paramount importance in neuro-oncology. In this study, we evaluated the clinical significance of several important molecular markers in a very large cohort of 453 lower grade gliomas (including 244 diffuse astrocytomas, 73 anaplastic astrocytomas, 31 oligodendrogliomas, 17 anaplastic oligodendrogliomas, 76 oligoastrocytomas and 12 anaplastic oligoastrocytomas) from Prince of Wales Hospital (Hong Kong) and Huashan Hospital (Shanghai). Mutational analysis was conducted in IDH, CIC, FUBP1 and TERT promoter by direct sequencing and 1p/19q codeletion and EGFR amplification were evaluated by fluorescent in-situ hybridization. Protein expressions of IDH1-R132H, CIC, FUBP1, EGFR, INA, p53 and PDGFRA were examined by immunohistochemistry. IDH mutation, detected in 69% of lower grade gliomas, represented a crucial marker in classifying the tumors into two groups with distinct prognosis, the favorable IDH mutated group and unfavorable IDH wild type group. 1p/19q codeletion, present in 20% of lower grade gliomas, identified tumors with oligodendroglial histology and favorable prognosis within the IDH mutated group. This IDH mutated-1p/19q codeleted genetic signature was frequently found in incidentally-discovered low grade gliomas, a clinical subgroup of tumors with excellent prognosis. CIC and FUBP1 mutations, detected in 47% and 16% of oligodendroglial tumors respectively, were oligodendroglial markers which conferred unfavorable prognosis to patients within IDH mutated-1p/19q codeleted oligodendroglial tumors. Among IDH mutated-1p/19q intact gliomas, p53 positive expressing tumors exhibited worse prognosis and PDGFRA positive expressing tumors showed better prognosis. TERT promoter mutation, identified in 28% of lower grade gliomas, exhibited as an oligodendroglial marker and favorable prognostic factor within the IDH mutated group and highlighted a subgroup of aggressive astrocytic tumors with short survival within the IDH wild type group. EGFR amplification, observed in 7% of lower grade gliomas, occurred exclusively in IDH wild type tumors, correlated with TERT promoter mutation and contributed a subset of tumors with fatal prognosis. Taken together, this study identifies objective and clinically relevant biomarkers which define lower grade gliomas into molecular subgroups with distinct clinico-pathological features. The biomarkers not only provide adjuncts to tumor classification beyond histology but potentially facilitate standardization of treatment strategy. With continuous efforts, I believe that this information will ultimately contribute to patient care in neuro-oncology in the era of personalized medicine. / 瀰漫性腦膠質瘤是最常見的原發性腦癌，可根據形態學分為星形細胞瘤、少枝膠質細胞瘤和少枝星形細胞瘤，並根據惡性特徵分為II至IV級。雖然膠質母細胞瘤(Ⅳ級)有標準的手術和術後化放療方案，低級別膠質瘤(Ⅱ和Ⅲ級)在治療方案和臨床結果上仍有很大的變異。目前世界衛生組織就膠質瘤的分類是純基於組織學，因此存在著觀察者間的變異，而抽樣誤差和活檢組織樣本太小亦加劇此問題。客觀和俱臨床價值的標誌物在低級別膠質瘤亦相對缺乏。為了改善腫瘤診斷和治療，未來膠質瘤分類將會加入分子標誌物，因此探討預後標誌物在神經腫瘤研究領域極為重要。我們從香港威爾斯親王醫院和上海華山醫院採集了453例低級別膠質瘤樣本，並對幾個重要的分子標誌物的臨床意義進行評估。我們以直接測序分析IDH，CIC，FUBP1和TERT啟動子突變，以熒光原位雜交技術檢測染色體1p/19q雜合性缺失和EGFR基因擴增，並以免疫組化檢測IDH1-R132H，CIC，FUBP1，EGFR，INA，p53和PDGFRA蛋白表達。IDH的突變率為69%，它把膠質瘤分成兩組: 預後好的IDH突變型組和預後差的IDH野生型組。1p/19q雜合性缺失的發生率為20%，主要是IDH突變型組內的少枝膠質細胞瘤，有較好的預後。IDH突變-1p/19q雜合性缺失這個基因特徵經常出現在偶發低級別膠質瘤，是一組預後良好的臨床亞組。CIC和FUBP1在少枝膠質腫瘤的突變率分別為47%和16%，在IDH突變-1p/19q雜合性缺失的少枝膠質腫瘤有不良的預後。在IDH突變-1p/19q完整的膠質瘤，p53陽性表達的腫瘤預後較差，PDGFRA陽性表達的腫瘤則預後較好。TERT啟動子的突變率為28%。在IDH突變型組，TERT啟動子突變表現為少枝膠質標誌物，出現在預後良好的腫瘤;在IDH野生型組，TERT啟動子突變則出現在一組生存期很短的星形細胞腫瘤亞組。EGFR基因擴增的發生率為7%，只出現在IDH野生型腫瘤，與TERT啟動子突變有相關性，並有致命性的預後。綜上所述，本研究確定了客觀的臨床標誌物，為膠質瘤分類提供組織學以外的參考，更為制定標準治療方案奠定基礎。在這個體化醫療時代，本人相信這些資訊最終將有助於神經腫瘤病人的治理。 / Chan, Ka Yin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 159-186). / Abstracts also in Chinese. / Title from PDF title page (viewed on 02, December, 2016). / Detailed summary in vernacular field only.

Glioblastoma (GBM) is the most common intrinsic primary brain tumour. It is uniformly fatal, with median survival approximately 14 months. These tumours comprise a mixture of neural stem cell-like cells and more differentiated astrocytic cells. The former are thought to be responsible for tumour development and recurrence, and display self-renewal and differentiation capacity in vitro. Glioma stem cells (GSCs) are defined operationally by their capacity to initiate tumours on orthotopic transplant into immunocompromised mice. The Pollard lab has identified the neural developmental transcription factor Forkhead Box G1 (FOXG1) as the most consistently overexpressed gene in GBM-derived neural stem (GNS) cells compared to their genetically normal neural stem (NS) cell counterparts. Here we explore the function and critical downstream effectors of FOXG1 in NS and GNS cells. We find that, although FOXG1 is not essential for sustaining proliferation of NS or GNS cells (in vitro), high FOXG1 restricts astrocyte differentiation in response to BMP and can drive dedifferentiation of postmitotic astrocytes. We identify a potential cooperation with SOX2. ChIP-Seq and RNA-Seq were used to define transcriptional targets. FOXG1 directly controls critical cell cycle regulators FOXO3 and FOXO6 (two forkhead family proteins), as well as the proto-oncogene MYCN and key regulators of both DNA and chromatin methylation, including TET3 and CHD3. Pharmacological inhibitors of MYC block FOXG1-driven de-differentiation, whereas Vitamin C and 5-azacytidine – agents that disrupt DNA and chromatin methylation – can facilitate de-differentiation. CRISPR/Cas genome editing was used to genetically ablate the cell cycle inhibitor FOXO3, or remove the FOXG1-bound cis-regulatory region. These data suggest direct transcriptional repression of FOXO3 by FOXG1 may drive cells into cycle. We conclude that high levels of FOXG1 in GBM limit astrocyte differentiation commitment by direct transcriptional control of core cell cycle regulators and DNA/histone methylation.

by Liu Heng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 115-138). / Acknowledgments --- p.I / List of Abbreviations --- p.II / Abstract --- p.V / Chapter Chapter 1: --- Introduction / Chapter 1.1 --- Cytokines in the Central Nervous System --- p.1 / Chapter 1.1.1 --- Basic Properties of Cytokines --- p.1 / Chapter 1.1.2 --- The General Characteristics of Glial Cells --- p.4 / Chapter 1.1.2.1 --- Astrocytes --- p.4 / Chapter 1.1.2.2 --- Oligodendrocytes --- p.6 / Chapter 1.1.2.3 --- Microglial --- p.7 / Chapter 1.1.3 --- The Effects of Cytokines on Neural Cells --- p.7 / Chapter 1.1.3.1 --- TNF-α and Neural Cells --- p.8 / Chapter 1.1.3.2 --- LIF and Neural Cells --- p.10 / Chapter 1.1.3.3 --- IL-1 and Neural Cells --- p.12 / Chapter 1.1.3.4 --- IL-6 and Neural Cells --- p.14 / Chapter 1.1.4 --- Immune Response in the Central Nervous System --- p.16 / Chapter 1.2 --- The C6 Glioma as a Model for the Study of Glial Cell Growth and Differentiation --- p.21 / Chapter 1.2.1 --- The Rat C6 Glioma Cells --- p.21 / Chapter 1.2.2 --- The Differentiation and Proliferation of C6 Glioma Cells --- p.23 / Chapter 1.3 --- Signal Transduction Pathways in Cytokine-stimulated Glial Cells --- p.28 / Chapter 1.3.1 --- Intracellular Signalling Pathways of Cytokines --- p.28 / Chapter 1.3.1.1 --- Protein Kinase C Pathway --- p.29 / Chapter 1.3.1.2 --- Tyrosine Kinase Pathway --- p.30 / Chapter 1.3.1.3 --- Cyclic Nucleotide Pathway --- p.32 / Chapter 1.3.1.4 --- Nitric Oxide Pathway --- p.33 / Chapter 1.3.2 --- Intracellular Signalling Pathways in Cytokine-stimulated C6 Glioma Cells --- p.34 / Chapter 1.4 --- The Aims of This Thesis Project --- p.37 / Chapter Chapter 2: --- Materials and Methods --- p.41 / Chapter 2.1 --- Rat C6 Glioma Cell Culture --- p.41 / Chapter 2.1.1 --- Preparation of Culture Media --- p.41 / Chapter 2.1.1.1 --- Complete Dulbecco's Modified Eagle Medium --- p.41 / Chapter 2.1.1.2 --- Complete Roswell Park Memorial Institute1640 Medium --- p.42 / Chapter 2.1.2 --- Maintenance of the C6 Cell Line --- p.42 / Chapter 2.1.3 --- Cell Preparation for Assays --- p.43 / Chapter 2.2 --- Determination of Cell Proliferation --- p.44 / Chapter 2.2.1 --- Determination of Cell Proliferation by [3H]-Thymidine Incorporation --- p.44 / Chapter 2.2.2 --- Measurement of Cell Viability Using Neutral Red Assay --- p.45 / Chapter 2.2.3 --- Data Analysis --- p.45 / Chapter 2.3 --- Effects of Cytokines and Lipopolysaccharide on C6 Cell Proliferation --- p.46 / Chapter 2.4 --- Effects of Protein Kinase C Activators and Inhibitors on Cytokine-induced C6 Cell Proliferation --- p.47 / Chapter 2.5 --- Effects of cAMP or cGMP on Cytokine-induced C6 Cell Proliferation --- p.48 / Chapter 2.6 --- Effects of Tyrosine Kinase Inhibitors on Cytokine-induced C6 Cell Proliferation --- p.48 / Chapter 2.7 --- Effects of Calcium Ion on Cytokine-induced C6 Cell Proliferation --- p.49 / Chapter 2.8 --- Effects of Nitric Oxide on Cytokine-induced C6 Cell Proliferation --- p.49 / Chapter 2.8.1 --- Effects of Sodium Nitroprusside and Nitric Oxide Synthase Inhibitors on Cytokine-induced C6 Cell Proliferation --- p.49 / Chapter 2.8.2 --- Nitric Oxide Production Assay --- p.50 / Chapter 2.9 --- Effects of β-Adrenergic Receptor Agonist and Antagonist on Cytokine-induced C6 Cell Proliferation --- p.51 / Chapter 2.10 --- Morphological Studies on Cytokine-Treated C6 Glioma Cells --- p.51 / Chapter 2.10.1 --- Wright-Giesma Staining --- p.52 / Chapter 2.10.2 --- Glial Fibrillary Acidic Protein Staining --- p.52 / Chapter 2.10.3 --- Hematoxylin Staining --- p.53 / Chapter Chapter 3: --- Results --- p.55 / Chapter 3.1 --- Effects of Cytokines on C6 Cell Proliferation --- p.55 / Chapter 3.1.1 --- Effects of Cytokines on C6 Cell Proliferation --- p.56 / Chapter 3.1.2 --- The Time Course of Cytokine-induced C6 Cell Proliferation --- p.59 / Chapter 3.1.3 --- Effects of Lipopolysaccharide on C6 Cell Proliferation --- p.61 / Chapter 3.1.4 --- Effects of Cytokines on the Growth of C6 Cells --- p.64 / Chapter 3.2 --- Morphology and GFAP Expression in Cytokine-treated C6 Glioma Cells --- p.64 / Chapter 3.2.1 --- Effects of Cytokines on the Morphology of C6 Cells --- p.64 / Chapter 3.2.2 --- Effects of Cytokines on GFAP Expression in C6 Glioma Cells --- p.66 / Chapter 3.3 --- The Signalling Pathway of Cytokine-induced C6 Cell Proliferation --- p.69 / Chapter 3.3.1 --- The Involvement of Protein Kinase C in Cytokine-induced C6Cell Proliferation --- p.71 / Chapter 3.3.2 --- The Involvement of Tyrosine Kinase in the Cytokine- induced C6 Cell Proliferation --- p.81 / Chapter 3.3.3 --- The Involvement of Calcium Ions in Cytokine-induced C6 Cell Proliferation --- p.87 / Chapter 3.3.4 --- The Involvement of Cyclic Nucleotides in Cytokine- induced C6 Cell Proliferation --- p.92 / Chapter 3.3.5 --- The Involvement of Nitric Oxide in Cytokine-induced C6 Cell proliferation --- p.94 / Chapter 3.3.6 --- The Involvement of P-Adrenergic Receptor in Cytokine- induced C6 Cell Proliferation --- p.101 / Chapter Chapter 4: --- Discussion and Conclusions --- p.104 / References --- p.115

Glioblastoma (GB) é o tumor cerebral maligno mais frequente. O prognóstico para os pacientes é ruim e a sobrevida média após o diagnóstico varia de 6 meses a 1 ano. Isso ocorre devido à ineficácia das estratégias terapêuticas dos tratamentos atuais, pois esses tipos de tumores são altamente invasivos. Deste modo, novas estratégias terapêuticas são necessárias. Neste contexto surge a doxazosina (2 - {4 - [(2,3-dihidro-1,4-benzodioxano-2-il) carbonil] piperazina-1-il} -6,7-dimetoxiquinazolina-4amina, um composto quinazolínico pertencente à classe farmacológica dos antagonistas dos receptores adrenérgicos α1, amplamente utilizada na clínica para o tratamento de pressão arterial elevada, assim como no tratamento de retenção urinária relacionado com a hiperplasia benigna da próstata (BPH). O presente estudo avaliou os efeitos do tratamento com doxazosina em modelos experimentais de gliomas humano (U-138MG) e de rato (C6). Observamos que a doxazosina foi capaz de inibir a viabilidade na linhagem celular de glioma de rato C6. Além disso, o fármaco permaneceu estável no meio de cultura após 48 horas de incubação e foi captado pelas células de glioma C6, não apresentando efeito tóxico sobre as células não tumorais (cultura organotípica e cultura primária de astrócitos) em concentrações inferiores a 250µM. Os resultados mostraram que doxazosina foi capaz de diminuir a densidade celular e induzir a morte celular em ambas as linhagens (U-138MG e C6). Além disso, o fármaco induziu a diminuição da fosforilação das proteínas Akt e GSK-3β em 24 e 48hs de tratamento. São vários os possíveis mecanismos que possam estar associados com a ação da doxasozina, dentre eles apoptose, necrose, senescência e/ou autofagia. / Glioblastoma (GB) is the most frequent and most malignant human brain tumor. The prognosis for the patients with GB remains dismal, as median survival after diagnosis varies from 6 month to 1 year. This is largely due to the inability of current treatment strategies to address the highly invasive nature of this disease. Thus, new therapeutic strategies are needed. Doxazosin (2-{4-[(2,3-dihydro-1,4-benzodioxin-2yl)carbonyl]piperazin-1-yl}-6,7-dimethoxyquinazolin-4-amine, a quinazoline compound, is an selective α1-adrenoceptor antagonists, widely used for treatment of high blood pressure as well as in the treatment of urinary retention related with prostate benign hyperplasia (BPH). Doxazosin α1-adrenoceptor antagonists is a very promissing quinazoline drug, may represent chemical starting points to develop more potent death inducing agents free of α1-adrenoceptor antagonistic action and suitable for cancer treatment with minimal and well-tolerated side effects. Within this context, the present study was designed to evaluate the effects of doxazosin treatment in experimental models of gliomas. Doxazosin was able to viability inhibition of the C6 glioma cell line. Moreover, the drug seems to be stable in the culture medium after 48 hours of incubation and was taken up by C6 glioma cells and showed no toxic effect on non-tumor cells at concentrations below 250µM. The results showed that doxasozin was able to decrease cell density and induce cell death in both lineages. In addition, doxazosin induced the inactivation of Akt and of GSK-3β proteins after 24 and 48 hours. Taken together, our results show that doxazosin was able to significantly induce cells death of both, human and rat glioma lines (U-138MG and C6 respectively). The mechanisms associated with this effect involve apoptosis induction, necrosis, senescence or autophagy.

(<特集>悪性脳腫瘍の病態と治療) (<SPECIAL ISSUE>Pathology and Treatment of Malignant Brain Tumors)