BALB/c nude mice 6 weeks old were inoculated with glioma C6 cell-line and the efficacy of the different amount of Etanidazole-discs and Taxol-microspheres was investigated. Poly (D,L-lactic-co-glycolic acid) (PLGA) was used as the main encapsulating polymer and polyethylene glycol was added to increase the porosity. The 1% drug loading microspheres of each drug were produced by spray drying and the discs were obtained by compressing the Etanidazole-microspheres. Intra-tumoral injection followed by irradiation resulted in high systemic dosage and thus systemic toxicity. Tumors grown for 6 days, 9 days and 16 days were implanted with 0.5 mg or 1.0 mg or 1.5 mg of the drug. A radiation dosage of 2 Gy each time for a number of times was given for animals implanted with Etanidazole and no irradiation was given for animals implanted with Taxol. Increasing the number of doses clearly decreased the rate of tumor growth. The increase in the amount of drug on smaller sized tumors controlled the tumor better and there was agglomeration of the microspheres resulting in deviation of release profile of the drug as compared to the in vitro studies. It was observed that 1.0 mg of Taxol given to a tumor grown for 6 days was able to suppress the tumor for a total period of approximately two months and no tumor resurrection was observed during the second month. / Singapore-MIT Alliance (SMA)

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.

Gliomblastoma is a highly malignant tumor of the central nervous system that is resistant to radiation and chemotherapy. Evidences accumulated over recent years have indicated the phosphoinositide 3-kinase/Akt signal transduction pathway as one of the major factors implicated in cancer resistance to conventional therapies. In this study we determined whether inhibition of PI3K/Akt signal pathway through pharmacological and/or genetic manipulation could enhance radiation sensitivity in glioma cells. Our results showed 6 of 12 glioma cell lines with activated Akt mostly due to reciprocal down-regulation of PTEN activity (loss-of-function mutations) but not by PIK3CA gain-of-function mutations. U87 and U373 glioma cell lines with PTEN mutation showing strong Akt Ser473 phopshorylation were treated with PI3K inhibitor LY294002 and irradiated with 0, 2.5, 5 and 7.5 Gy of radiation dosages. The results showed LY294002 inhibited Akt actvation in the glioma cells and decreased clonogenic survival in a radiation dose-dependent manner. Expression of dominant-negative Akt and PTEN through adenovirus mediated gene delivery in U87 and U373 glioma cells sensitized tumor cells to radiation treatment. Furthermore, PDK1 and mTOR inhibitors were also used on radiation sensitivity test. But both inhibitors had no radiosensitization in glioma cells. Glioma invasion was linked to advanced tumor stages. Recently, Type 1 insulin-like growth factor regulates tumor invasion have been showed to be mediated through the PI3K/Akt signaling pathway. In this study, we treated glioma cells with LY294002 to analyze its effects on invasion and migration potentials of the tumor cells. The results showed LY294002 inhibited both abilities in most glioma cell lines in vitro. In addition we used adv-PTEN and adv-dnAkt to confirm these results. Adv-PTEN performed dramatic decrease in glioma cell invasion potentials. Furthermore, we investigated whehter PI3K downstream PDK1, and mTOR involved in tumor cell invasion. We used PDK1 and mTOR inhibitors in glioma and determined their effects on invasion by Boyden chamber assay. Unfortunately, both of inhibitors had only limited inhibition on glioma invasion. Take together, our results indicate the feasibility of using PI3K/Akt inhibiting genetic and pharmacological agents to induce glioma cells to become more sensitive to radiation treatment and reduced invasion potentials. However, glioma radiosensitization and invasion may also be regulated by other signaling pathway.

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.

Tese (doutorado)—Universidade de Brasília, Faculdade de Agronomia e Veterinária, Programa de Pós-Graduação em Saúde Animal, 2016. / Submitted by Patrícia Nunes da Silva (patricia@bce.unb.br) on 2016-05-05T13:35:39Z No. of bitstreams: 1 2016_FernandoFranciscoBorgesResende_Parcial.pdf: 3418973 bytes, checksum: 5b4e65156b74a878a317389ec662e94f (MD5) / Approved for entry into archive by Patrícia Nunes da Silva(patricia@bce.unb.br) on 2016-05-05T13:37:27Z (GMT) No. of bitstreams: 1 2016_FernandoFranciscoBorgesResende_Parcial.pdf: 3418973 bytes, checksum: 5b4e65156b74a878a317389ec662e94f (MD5) / Made available in DSpace on 2016-05-05T13:37:27Z (GMT). No. of bitstreams: 1 2016_FernandoFranciscoBorgesResende_Parcial.pdf: 3418973 bytes, checksum: 5b4e65156b74a878a317389ec662e94f (MD5) / O glioblastoma multiforme é o tumor cerebral mais agressivo. Já a micróglia representa 30% da massa tumoral e desempenha um importante papel na tumorigênese. Este trabalho buscou estudar o padrão de infiltração e alteração morfológica da micróglia no tecido tumoral formado por células da linhagem GL261mCherry implantadas ortotopicamente. Além disto, buscou-se examinar o papel do canal de potássio Kv 10.1, correlacionado ao crescimento tumoral, primeiro na interação da micróglia com as células tumorais e, segundo, frente à lesão celular causada pelo fármaco de escolha ao tratamento do glioma, a temozolomida. Camundongos CX3CR1-EGFP receberam injeções intracorticais de células de glioblastoma multiforme capazes de expressar a proteína fluorescente mCherry. Microscopia de epifluorescência e confocal foram empregadas nas análises morfométricas, ao passo que a microscopia do tipo 2-photon (2P-LSM) foi usada para visualizar as células tumorais e microgliais no cérebro de animais vivos. Os resultados deste estudo revelaram uma microgliose intensa em áreas cerebrais logo após a implantação do tumor, isto é, aos 30 minutos. Nos primeiros três dias, a micróglia tende a formar aglomerados de células em torno dos tumores. Para, em seguida, infiltrar no centro tumoral, onde permanece durante todos os pontos de tempo estudados, de 6 a 18 dias. Com o aumento da massa tumoral, as células tumorais perdem progressivamente a sua forma original, assumindo uma morfologia heterogênea e difusa; o tamanho do corpo celular (perímetro) passou de 10 µm, três dias após o implante, para 52 µm aos 18 dias. Em contato com o glioma, a micróglia também muda sua morfologia. A forma tornou-se amebóide, com corpos celulares alargados. O corpo celular (área) cresceu de 366±0.0 µm2, na micróglia em vigilância, para 1310±146.0 µm2 e ramificações curtas, ou mesmo ausência de ramificações no fenótipo ativado. Aos 12 dias após o implante, foi notada a presença de células multinucleadas de glioma, os policariócitos, em contato íntimo com a micróglia ativada. Sobre o canal Kv-10.1, este foi expresso em células cultivadas de glioma, de micróglia (linhagem BV-2) e também em tecido tumoral de camundongos implantados com o tumor. A supressão deste canal, em células de glioma, potencializou a injúria por TMZ em 29%, conforme ensaio de MTT. Em conclusão, a micróglia apresentou um padrão espaço-temporal de infiltração no glioma, o que favorece influências recíprocas e pró-tumorigênicas. Já o canal Kv-10.1, pode tanto representar uma via de comunicação entre estes tipos celulares, quanto ser um potencial alvo para a terapêutica do glioma, já que foi capaz de potencializar os efeitos da temozolomida na morte celular de linhagens de glioma. / Glioblastoma multiforme is the most aggressive brain tumor. Microglia represents 30% of the tumor mass, and plays a role in tumorigenesis. This work studied the pattern of microglial growth into brain tumor tissue formed by orthotopically implanted glioma cells of the established GL261 cell line. In addition, we examined the expression of the Kv 10.1 potassium channel that frequently correlates with tumor growth. CX3CR1-EGFP mice received intracortical injections of GL261 tumor cells with stable expression of the red fluorescent protein mCherry. Epifluorescence - and confocal laser-scanning microscopy were employed in the analysis of tissue sections, whereas two-photon laser-scanning microscopy (2P-LSM) was used to visualize tumor cells and microglia in the brain of living animals. Our results revealed an intense microgliosis in brain areas already shortly after tumor implantation, i.e. at 30 minutes. In the first three days, microglia formed clusters of cells around tumors mass. Then cells infiltrated the tumor area, where they remained during all the time points studied, from 6 to 18 days. As tumor increased in size, GL261 cells progressively lost their original shape, assuming a heterogeneous and diffuse morphology. Soma size increased from 10 to 52 µm. In contact with the glioma, microglia also changed its morphology. Cell bodies enlarged from 366±0.0 µm2, in quiescent microglia, to 1310±146.0 µm2. The shape became amoeboid, with enlarged cell bodies and short processes (or even absence of them). Remarkably, we found microglial processes that closely surrounded glioma cells. Microglia also grew around multinucleated polycariocytes, found in tumors at 12 days. The Kv 10.1 channel was expressed in cultured GL261 cells, microglia cell line (BV-2) and also in mouse tumors. Suppression of Kv10.1 caused a 29% decrease in the viability of glioma cells injured by TMZ. In conclusion, microglia presented a temporal and spatial pattern of infiltration in glioma tumors, which favors reciprocal and protumorigenic influences. Kv 10.1 expressed by glioma cells in close contact with microglia may represent a communication pathway between microglia and cancer cells and, could be a potential target for antiglioma gene therapy, since it potentiated the effects of temozolomide in glioma cell lines.

BACKGROUND: Glioblastoma multiforme (GBM) is a highly heterogeneous tumor of the central nervous system (CNS) that exhibits considerable variation in its clinical course. Recently, the World Health Organization (WHO) published a classification system for tumors of the CNS that combines histological features with molecular parameters to determine tumor grade. The incorporation of molecular biomarkers that carry both prognostic and predictive value adds another level of objectivity to the glioma grading system and will help guide clinical decision. As such, the assessment of biomarkers has become an integral part of tumor evaluation in neuro-oncology. This curriculum will discuss the clinical relevance of the most recently studied biomarkers with prognostic and predictive value in the evaluation of GBM. Biomarkers regularly used for the assessment of GBM include the IDH mutations, MGMT methylation status, and EGFRvIII. Furthermore, this review will offer a perspective on experimental approaches currently under investigation for treatment of GBM. LITERATURE REVIEW FINDINGS: MGMT methylation of the promoter region is associated with better treatment response from temozolomide (TMZ), an alkylating therapeutic. Treatment benefit was most prominent in the elderly population and therapy should be individualized for that age group. Patients with GBM characterized by IDH1/IDH2 mutations carry a better overall prognosis primarily due to their higher sensitivity to chemo- and radiotherapy. The prognostic value of EGFRvIII remains controversial, although it may be associated with a worse prognosis. Nonetheless, EGFRvIII provides an ideal target for targeted molecular therapies as it is only found on tumor cells. PROPOSED METHODS: A curriculum aimed at educating primary care providers (PCPs) about the most clinically significant biomarkers in GBM will be developed. The curriculum will be in a PowerPoint format, and the hour-long lecture will be presented at continuing medical education national conferences. A pre- and post-test consisting of the same 10 multiple- choice questions will be administered on a voluntary basis to help evaluate knowledge acquisition from the curriculum. Results will be evaluated with a paired t-test analysis. The tests will be will be administered through Poll Everywhere, a smartphone survey application. CONCLUSION: There is increasing evidence to suggest that therapies should be individualized according to specific biomarkers with predictive value. PCPs are in a position where they are often the first providers to suspect the diagnosis of a brain tumor. Therefore, it is imperative for PCPs to be aware of the latest development in the field of neuro-oncology so that they may appropriately counsel patients.

Nucleotídeos extracelulares são envolvidos em diversos processos patofisiológicos no sistema nervoso central. Astrócitos são a maior fonte de nucleotídeos extracelulares da adenina no cérebro e também importantes alvos para as ações desses nucleotídeos via receptores purinérgicos P2. As ações induzidas pela sinalização purinérgica são reguladas pelas ecto-nucleotidases, que incluem membros da família das ecto-nucleosídeo trifosfato difosfoidrolase (E-NTPDase), ecto-5’-nucleotidase (ecto- 5’N) e ecto-adenosina deaminase (ADA). Culturas de astrócitos preparadas de hipocampo, córtex e cerebelo de ratos foram capazes de rapidamente converter ATP extracelular a ADP, que foi então hidrolizado a AMP. Os nucleosídeos tri-fosfatados foram hidrolisados preferencialmente aos difosfatados em todas as estruturas cerebrais. A análise cinética sugere que varias ecto-nucleotidases estão envolvidas nessa cascata enzimática. Análises preliminares de mRNA por PCR indicaram que astrócitos expressam múltiplos membros da família das NTPDases (NTPDase1 a NTPDase3 e NTPDase5/6). Por RT-PCR quantitativo (Real-time PCR), nós identificamos a NTPDase2 (CD39L1) como a NTPDase predominante expressa por astrócitos de hipocampo, córtex e cerebelo de ratos. Astrócitos do cerebelo apresentaram um padrão diferente para a hidrólise do AMP, com uma atividade específica 7 vezes maior, quando comparada com astrócitos de hipocampo e córtex. Uma maior expressão da ecto-5’N por RT-PCR foi identificada nessa estrutura. Não houve acúmulo de adenosina extracelular em todas as estruturas estudadas, indicando a presença de uma alta atividade ecto-adenosina deaminase em astrócitos. Dipiridamol aumentou significativamente os níveis de inosina no meio extracelular de astrócitos de hipocampo e córtex, mas não em astrócitos de cerebelo. Essas diferenças observadas podem indicar heterogeneidade funcional dos nucleotídeos no cérebro. Com o objetivo de investigar as enzimas envolvidas no catabolismo dos nucleotídeos como indicadoras da invasividade e agressividade dos gliomas malignos, nós avaliamos a degradação dos nucleotídeos extracelulares em cinco linhagens de gliomas diferentes e comparamos com astrócitos. Todas as linhagens de gliomas examinadas apresentaram baixas razões de hidrólise quando comparadas com astrócitos. Resultados preliminares sugerem que a falta de expressão da NTPDase1 e 2 possam ser responsáveis pela baixa hidrólise de ATP nas linhagens de gliomas. Considerando que o ATP é reconhecido como um fator mitogênico que induz a proliferação em células de gliomas, a substancial diminuição na hidrólise de ATP e ADP observadas em gliomas, sugere que alterações na via das ecto-nucleotidases pode representar um importante mecanismo associado com a transformação maligna desse tipo de tumor.

Nos últimos anos, o ambiente marinho tem sido pesquisado para uma variedade de compostos com diferentes atividades biológicas. Entre todos os organismos marinhos, as esponjas representam uma das fontes mais promissoras de novas drogas contra o câncer. Embora o litoral brasileiro seja o segundo mais extenso depois da Austrália, existem poucos estudos com esponjas marinhas coletadas no Brasil objetivando a descoberta de novos fármacos. Nesse trabalho, nós investigamos os efeitos de diferentes extratos da esponja marinha Polymastia janeirensis na viabilidade de uma linhagem de glioma humano (U138MG). Além disso, avaliamos a seletividade do efeito, caracterizamos os mecanismos envolvidos no processo de morte celular e isolamos as frações ativas responsáveis pelas atividades encontradas. De uma maneira geral, um efeito antiproliferativo foi observado quando as células forma expostas aos extratos (aquoso e orgânico) da esponja. Entretanto, as doses mais altas (50 e 100 μg/ml) foram extremamente citotóxicas, inibindo mais de 80% a proliferação e a viabilidade celular. Além disso, uma morte celular por necrose foi observada com essas doses, enquanto uma morte celular por apoptose foi observada com a dose mais baixa (10 μg/ml). Nós também demonstramos que a rota apoptótica ativada em resposta aos extratos era a via intrínseca, e que a produção de radicais livres estava, pelo menos em parte, relacionada ao efeito bifásico (apoptose ou necrose) encontrado. Os resultados aqui apresentados demonstram a existência de uma seletividade do efeito citotóxico, uma vez que os extratos não induziram morte em culturas de astrócitos na dose em que foi observada morte por apoptose nos gliomas. Ademais, uma potente atividade apoptótica foi observada com o composto ativo isolado da esponja marinha alvo desse estudo. Os nossos resultados sugerem que a esponja marinha alvo desse estudo pode ser considerada uma boa fonte para o desenvolvimento de novas drogas contra o câncer. / Over the last years, the marine environment has been screened for a variety of compounds with different biological activities. Among all marine organisms, sponges represent one of the most promising source of new drug leads for cancer. Although Brazil has the second most extensive coastline after Australia, there are just few reports in which the authors have screened Brazilian sponge extracts for biological activities. In this work, we examine the anti-proliferative effects of crude extracts of the marine sponge Polymastia janeirensis in the U138MG human glioma cell line. Moreover, we investigate the effects on selective cytotoxicity in the glioma cells in comparison with a normal, untransformed cell culture, as well as examine the apoptotic pathway activated in response to treatments with extracts of P. janeirensis. Yet, we performed a bioassayguided fractionation to found the active fractions in the extracts. Exposure of glioma cells to treatments resulted in cell number decrease with both aqueous and organic extracts. Moreover, sponge extracts reduced glioma cell viability. However, higher doses (50 e 100 μg/ml) induced a stronger cytotoxic effect when compared to the lower dose tested (10 μg/ml), inhibiting more than 80% of cellular growth and viability. Our results showed that sponge extracts caused necrosis in the glioma cell line at higher doses, while a high percentage of apoptotic glioma cells were observed at 10 μg/ml. We also demonstrated that marine sponge extracts induces oxidative cell death through a receptor-independent pathway under our assays condictions, and ROS productions may be related to the biphasic effect (apoptosis or necrosis) observed. Furthermore, our results suggested a selective cytotoxic effect on glioma cell line compared to a normal cell culture, since the effect on viability found in glioma cells was not observed in astrocyte cultures with the lower dose (10 μg/ml). Yet, a strong apoptotic activity was observed with the active fraction isolated from P. janeirensis. Our results suggest that this marine sponge may be considered a good source for new antiglioma metabolites.

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.

Submitted by Pós Imunologia (ppgimicsufba@gmail.com) on 2017-02-07T17:30:21Z No. of bitstreams: 1 Paulo Coelho (1).pdf: 1228067 bytes, checksum: 335f72b50ca0e3a7b22d4b1d10111096 (MD5) / Approved for entry into archive by Delba Rosa (delba@ufba.br) on 2017-02-08T15:49:23Z (GMT) No. of bitstreams: 1 Paulo Coelho (1).pdf: 1228067 bytes, checksum: 335f72b50ca0e3a7b22d4b1d10111096 (MD5) / Made available in DSpace on 2017-02-08T15:49:23Z (GMT). No. of bitstreams: 1 Paulo Coelho (1).pdf: 1228067 bytes, checksum: 335f72b50ca0e3a7b22d4b1d10111096 (MD5) / CAPES / Gliomas são as neoplasias intracraniais mais comuns e malignas. O entendimento da biologia tumoral dos gliomas é um processo complexo e contraditório. Nossos estudos anteriores demonstram uma capacidade antitumoral e anti-angiogênica de flavonoides, além de potencial morfogênico e imunomodulador de células gliais não transformadas com liberação de TNF e NO. Neste trabalho objetivamos investigar as propriedades antitumorais e imunomodulatórias do flavonoide apigenina, extraído da Croton betulaster mull em culturas de células de glioma da linhagem C6. Inicialmente, investigamos os efeitos inibitórios e morfogênicos do flavonoide nas células de C6. Verificamos pelo teste de MTT e após coloração com azul de tripan, que a apigenina tem a capacidade em diminuir a viabilidade celular e a proporção de células viáveis de forma dose e tempo dependente. Ainda, após 72 h do tratamento das culturas com 100 μM da apigenina, uma significativa proporção de células apresentaram marcação positiva para anexina V (29,6%), caracterizando apoptose, e uma menor proporção marcação positiva para laranja de acridina (6%), caracterizando autofagia. Por outro lado, o flavonoide também induziu um acúmulo das células na fase G0/G1 do ciclo celular, além de inibir a migração celular desde 24 h após o tratamento. Ademais, a capacidade do flavonoide em induzir alterações morfológicas nas células de glioma foi também observada, caracterizada pela emissão de prolongamentos multipolares nas células e aumento da expressão de proteína astrocitária GFAP, em detrimento da proteína nestina, marcador de precursor neural. A ação imunomodulatória da apigenina também foi caracterizada por citometria em fluxo, sendo evidenciado uma diminuição da proporção de células expressando NFkB nenhuma alteração significativa em STAT3 e p-STAT3, ambas proteínas envolvidas na sinalização da resposta imune. Este efeito foi acompanhado de uma alteração no perfil de citocinas pró- e antiinflamatórias evidenciadas por ELISA. Nas culturas em condições controle os níveis de IL-10 (396 pg/ml) foram cerca de duas vezes superior àqueles de TNF (216 pg/ml), porém os níveis de IL-10 diminuíram para 132 pg/ml após exposição à uma dose subtóxica do flavonoide (50 μM); um aumento significativo de NO foi também verificado nestas condições. Os conjuntos destes resultados demonstraram que o flavonoide apigenina possui eficiente efeito sobre a viabilidade, crescimento e proliferação, das células de glioma, além de induzir diferenciação celular, e mudanças no perfil de citocinas envolvidas no processo regulatório da resposta imunológica, colocando esta droga como um possível candidato adjuvante para o tratamento dos tumores cerebrais malignos humanos. / Gliomas are the most common intracranial neoplasms and malignant. The understanding of tumor biology of gliomas is complex and contradictory. Our previous studies have shown an ability antitumor and anti-angiogenic flavonoids, morphogenic and immunomodulatory potential of glial cells not transformed with release of TNF and NO. In this work we aimed to investigate the immunomodulatory and antitumor properties of apigenin flavonoid extracted from Cronton betulaster mull in cell cultures of C6 glioma lineage. Initially, we investigated the inhibitory effects of flavonoid and morphogenesis in cell C6. We verified by MTT assay and after staining with trypan blue, that apigenin has the ability to reduce cell viability and the proportion of viable cells in a dose and time dependent. Even after 72 h of treatment of cultures with 100 mM of apigenin, a significant proportion of cells showed positive staining for Annexin V (29.6%), typical of apoptosis, and a minor proportion stained positive for acridine orange (6%) , featuring autophagy. Moreover, the flavonoid also induced an accumulation of cells in G0/G1 phase of the cell cycle, besides inhibiting cell migration from 24 h after treatment. Furthermore, the capability of the flavonoid in inducing morphological changes in glioma cells was also observed, characterized by the emission of extension multipolar cells and increased expression of GFAP astrocytic protein, rather than protein nestin, a marker of neural precursor. The immunomodulatory action of apigenin was also characterized by flow cytometry, as evidenced increased proportion of cells expressing the active form of phosphorylated STAT-3 (p-STAT), and decreased the proportion of cells expressing NFkB, both proteins involved in signaling immune response. This effect was accompanied by a change in the profile of pro-and anti-inflammatory evidenced by ELISA. In cultures in control conditions levels of IL-10 (396 pg / ml) were approximately twice those of TNF (216 pg / ml), but their levels of IL-10 decreased to 132 pg / ml after exposure to a subtóxica dose of flavonoid (50 mM), a significant increase of NO was also observed under these conditions. The sets of these results demonstrated that the flavonoid apigenin has efficient effect on the viability, growth and proliferation of glioma cells, and inducing cellular differentiation, and changes in the profile of cytokines involved in the regulatory process of immune response, placing this drug as an possible candidate for the adjuvant treatment of malignant human brain tumors.