Cancer has become the major factor causing death in Taiwan. Although brain tumor take a few ratio in cancer, the current therapy shown not effect well. In previous studies, EGCG will promote cancer cells to go apoptosis after treatment with EGCG. But the mechanism in brain tumor is unknown. So, we use EGCG from green tea extract to investigate cell death of human brain tumor cell lines GBM8401, U87MG and U251. The metabolic rates of GBM8401, U87 and U251 are decrease with EGCG treatment, and it is significant in GBM8401. We also examine some genes and proteins related apoptosis by RT-PCR and Western blotting. The accumulation of p21, p27 and p53 are increasing with concentration and time course treatments. EGCG can inhibit the ability of brain tumor to form foci in anchorage-independent growth assay. Our data show that EGCG can inhibit brain tumor cell lines GBM8401, U87 and U251. It is validated that EGCG has the potential of cancer therapy and prevention.

Thesis (M.S.)--University of Michigan, 1969.

Thesis (doctoral)--University of Göteborg, 1992. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1969.

Thesis (doctoral)--University of Göteborg, 1992. / Added t.p. with thesis statement inserted. Includes bibliographical references.

No description available.

No description available.

In the current study we tested the hypothesis that tumorigenic transformation of T cells may result from aberrant regulation of autocrine growth factor production. We describe for the first time characterization of several normal T cell lines that underwent spontaneous transformation resulting from constitutive expression of interleukin-2 (IL-2) and interleukin 2 receptor (IL-2R) genes. Such cell lines could induce tumors <i>in vivo</i> and furthermore, the growth of such transformed cells both <i>ex vivo</i> and <i>in vivo</i> could be inhibited by monoclonal antibodies (mAbs) or antisense oligonucleotides specific for IL-2 or IL-2R. Interestingly, an <i>in vivo</i> originated T cell lymphoma, LSA, was also found to be dependent on constitutive production of IL-2 and Interleul(in-4 (IL-4). Together, these data demonstrated that dysregulation in the production or responsiveness to autocrine T cell growth factors, plays an important role in T cell transformation and tumorigenicity. Due to their ability to produce T cell growth factors, such tumor cells were found to be highly immunogenic. Thus it was surprising that some T cell lymphomas could still grow in an immunocompetent host and kill the host. To this effect, we investigated additional mechanisms used by such tumor cell lines to grow in an immunocompetent host. It was noted that the tumor cells used mechanisms such as failure to express MHC and production of immunosuppressive cytokines, such as, transforming growth factor-β (TGF-β) and interleukin-10 (IL-10), to evade the action of the immune system. In addition, the T cell lymphomas constitutively expressed F as-ligand and triggered apoptosis of host T cells that expressed Fas. Together, the current study suggests that cytokines produced by the tumor cells play an important role in tumorigenic transformation as vvell as maintenance of tumor growth in an immunocompetent host. / Ph. D.

O câncer é uma das principais causas de morte em todo o mundo, sendo as neoplasias malignas de pulmão, estômago, fígado, cólon e mama em maior número. E, recentemente, observa-se na literatura um grande número de trabalhos onde novos materiais, especialmente nanoparticulados, vêm sendo estudados como carreadores de drogas e radioisótopos aplicados ao tratamento do câncer. Como materiais mesoporosos à base de sílica, graças a sua enorme área superficial e biocompatibilidade, têm sido estudados intensivamente propiciando amplas aplicações em várias áreas, o emprego da sílica SBA-16 nanoestruturada podem vir a ser um específico carreador de radioisótopos acumulando-os nas células malignas. Com isso a proposta deste estudo é desenvolver estudos in vitro utilizando SBA-16 capaz de concentrar seletivamente nas células malignas quantidades terapêuticas do radioisótopo Gadolínio-159 conduzindo-as a morte. Neste trabalho foi realizada a síntese da sílica mesoporosa ordenada, SBA-16 e a incorporação do complexo Gd-DTPA-BMA, assim como a caracterização química e estrutural. As técnicas utilizadas para analisar a ocorrência da incorporação do complexo de gadolínio na matriz de sílica foram análise elementar, espectroscopia de emissão atômica (ICP-AES), análise elementar (CHN), espectroscopia na região do infravermelho (FTIR), adsorção de nitrogênio (BET), difração de raios-x a baixos ângulos (SAXS) e análise termogravimétrica (TG). Para análise da morfologia da sílica pura utilizou-se a microscopia eletrônica de varredura (MEV) e microscopia eletrônica de transmissão (MET). Por espectroscopia de correlação de fótons (PCS) foi possível obter a medida do tamanho médio das partículas, o índice de polidispersividade (PDI) da sílica SBA-16 e o potencial zeta por anemometria de laser Doppler (LDA). Os resultados de incorporação analisados por ICP-AES indicaram que o material SBA-16 obteve um alto índice de incorporação do gadolínio (93 %). A cinética de liberação, em fluído simulado corpóreo, apresentou estabilidade considerável e baixo teor de liberação (1 %). A sílica mesoporosa SBA-16 apresentou viabilidade celular em contato direto com cultura de células. As amostras, com gadolínio incorporado na matriz de sílica, após da irradiação não apresentaram atividade citotóxica expressiva, o que implica que esses estudos devem aprimorados para que mais pesquisas na área de nanobiotecnologia sejam realizadas. / Cancer is a leading cause of death worldwide, and malignant neoplasms of the lung, stomach, liver, colon and breast in greater numbers. And recently observed in the literature a large number of reviews where new materials, especially nanoparticle, has been studied as drug carriers and radioisotopes applied to cancer treatment. How mesoporous materials based on silica, thanks to its huge surface area and biocompatibility, have been studied intensively providing broad applications in various areas, the use of nanostructured silica SBA-16 might be a carrier specific radioisotope accumulate in the cells malignant. Thus the aim of this study is to develop in vitro studies using SBA-16 can selectively concentrate in malignant cells therapeutic amounts of the radioisotope Gadolinium-159 escorting them to death. This work was performed orderly synthesis of mesoporous silica, SBA-16 and incorporating the complex Gd-DTPA-BMA, as well as chemical and structural characterization. The techniques used to analyze the occurrence of the incorporation of the gadolinium complex in the silica matrix were elemental analysis (CHN), atomic emission spectroscopy (ICP-AES), infrared spectroscopy (FTIR), nitrogen adsorption (BET), small-angle X-ray scattering (SAXS) and thermogravimetric analysis (TG). To analyze the morphology of pure silica used the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). By photon correlation spectroscopy (PCS) it was possible to obtain a measure of mean particle size, the polydispersity index (PDI) of the silica SBA-16, and the zeta potential by laser Doppler anemometry (LDA). The results of incorporation analyzed by ICP-AES indicated that the material SBA-16 had a higher rate of incorporation of gadolinium (93%). The release kinetics in simulated body fluid, showed considerable stability and low release (1%). The mesoporous silica SBA-16 showed cell viability in direct contact with cell culture. Samples with gadolinium incorporated in the silica matrix after irradiation showed no significant cytotoxic activity, implying that these studies should improved so that more research in nanobiotechnology are performed.

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