Método para clonagem, expressão e purificação do polipeptídeo amilóide das ilhotas pancreáticas humanas

Em 15/04/2016: Anuidade de pedido de patente de invenção no prazo ordinárioDepositadaMétodo para clonagem e expressão do polipeptídeo das ilhotas pancreáticas (IAPP) maduro humano sob a forma recombinante, utilizando um sistema de expressão heteróloga em Escherichia coli baseado no promotor Lacl-T7 RNA polimerase, no qual um fragmento de DNA que contém a seqüência que codifica o peptídeo maduro de IAPP é amplificado por transcrição reversa e reação em cadeia da DNA polimerase (RT-PCR) a partir de RNA total derivado de ilhotas pancreáticas humanas, clonado em vetor de expressão como descrito acima e expresso em bactérias, e método de purificação empregando-se as etapas de lise das células, centrifugação do meio e resuspensão do precipitado em presença de agente desnaturante, centrifugação da solução, remoção do material insolúvel, coleta e filtração do sobrenadante clarificado, ligação da proteína a coluna de afinidade contendo íons metálicos imobilizados, clivagem com protease e eluição da rh-lAPP em forma purificada

Caracterization and isolation of genes involved in human gliomas by functional genome and in silico anlysis

São poucos os avanços obtidos em intervenções cirúrgicas ou terapias para melhora na qualidade de vida e/ou prognósticos dos pacientes acometidos por gliomas, que são os tumores mais comuns e fatais que acometem o sistema nervoso central. O modelo celular ST1 de glioma de rato responde ao tratamento com hormônio glicocorticóide (GC) com uma reversão fenotípica tumoral-normal in vitro e in vivo e o modelo celular P7 é resistente a este tratamento. Ambas as linhagens são utilizadas, no laboratório, como modelos de estudo de genes associados à origem de neoplasias e controle de proliferação celular, com potenciais aplicações na doença humana. Este trabalho possui dois objetivos gerais: a) clonagem e caracterização funcional do gene NRP/B de rato, previamente descrito no laboratório como sendo induzido durante o tratamento das células ST1 com GC; b) identificação de genes humanos no locus 22q13, frequentemente deletado e associado à progressão tumoral de gliomas. A identificação, clonagem e determinação da seqüência completa de NRP/B de rato, até então desconhecida, foi realizada neste trabalho e depositada no GenBank (número de acesso AY669396). Sua expressão parece ser cérebro-específica, sendo modulada positivamente durante o tratamento com GC nas células ST1. A superexpressão de NRP/B em células ST1 foi realizada para avaliar o papel do gene na reversão fenotípica tumoral-normal induzida por GC. Os resultados obtidos sugerem que NRP/B provoca diminuição da capacidade de crescimento independente de ancoragem em meio semi-sólido e do potencial tumorigênico das células ST1 em ensaios de tumorigênese in vivo. Experimentos preliminares sugerem o envolvimento da expressão de NRP/B no processo de progressão celular e em tumores humanos cerebrais e de mama. Para a identificação de genes humanos no locus 22q13 associados ao desenvolvimento de gliomas, foram adotadas duas estratégias: utilização do Banco de Dados do Transcriptoma para identificação de mRNAs e ESTs alinhadas no locus associado ao câncer cerebral 22q13 e utilização dos dados de genes localizados no cromossomo 22 diferencialmente expressos em microarrays entre as linhagens ST1 e P7, ambas tratadas com GC. Como resultado da análise in silico, foram selecionados alguns genes para análise por Q-PCR em linhagens celulares e amostras clínicas de gliomas humanos, o que evidenciou a existência de algumas correlações positivas ao nível transcricional entre os genes. Três genes (KIAA1644, SULT4A1 e PARVG) apresentaram maior expressão em amostras clínicas de cérebro não-tumoral quando comparadas com amostras de gliomas, o que sugere um possível envolvimento destes na progressão de gliomas humanos. A caracterização dos alvos moleculares na ação dos genes analisados neste estudo é importante para melhor entendimento dos mecanismos moleculares que controlam a proliferação celular e, futuramente, para o desenvolvimento de novas estratégias terapêuticas para estes tumores cerebrais.Gliomas are the most fatal central nervous system tumors and to date, satisfactory results from chemotherapies or surgical interventions are still not available. The ST1 rat glioma cell line is hyper-responsive to treatment with glucocorticoids (GC), undergoing a complete tumoral to normal phenotypic reversion, both in vitro and in vivo. The P7 glioma cell line is resistant to the action of GC. Both cell models are used in our lab to search for targets which are important to understand the origin of tumors and the control of cell proliferation. For the present study, we aimed at: a) cloning and functional characterization of the rat NRP/B gene, which had previously been identified as being induced during GC-treatment of the ST1 cells; b) identification of human genes located at the 22q13 locus, known to be involved in gliomagenesis. The previously unknown cDNA for rat NRP/B was identified, cloned, sequenced, and deposited in the GenBank (Acc. Nº AY669396). It displays brain-specific expression and positive modulation during GC treatment of ST1 cells. The role of NRP/B in the tumoral to normal phenotypic reversion induced by GC was analyzed by its overexpression in ST1 cells. The results suggest that induction of NRP/B partially impairs cell growth in semi-solid substrate and lowers its tumorigenic potential in vivo. Preliminary studies suggest that NRP/B expression is involved in cell cycle progression and in brain and human breast tumors. To identify additional human genes located in the glioma-related 22q13 locus, two strategies were used: a) analysis of the Ludwig - Fapesp Transcriptome Project database to identify mRNAs and ESTs that align to the referred locus and b) analysis of microarray data of differentially expressed genes in ST1 and P7 cells (both treated with GC) that also localize in chromosome 22. To validate the in silico analysis, Q-PCR was used to evaluate the expression of several genes in human brain tumor cell lines and clinical samples, being possible to find some positive correlations between genes at the transcriptional level. Three genes (KIAA1644, SULT4A1 e PARVG) displayed significantly higher expression levels in non-tumoral clinical samples, when compared to their tumor counterparts suggesting their involvement in human glioma progression. A better understanding of the molecular mechanisms by which these genes are involved may contribute with important information to understand the control of cell proliferation and may lead, in the future, to the development of new therapeutical strategies for brain cancer therapy and diagnosis

Overexpression of Nrp/b (nuclear restrict protein in brain) suppresses the malignant phenotype in the C6/ST1 glioma cell line

Upon searching for glucocorticoid-regulated cDNA sequences associated with the transformed to normal phenotypic reversion of C6/ST1 rat glioma cells, we identified Nrp/b (nuclear restrict protein in brain) as a novel rat gene. Here we report on the identification and functional characterization of the complete sequence encoding the rat NRP/B protein. The cloned cDNA presented a 1767 nucleotides open-reading frame encoding a 589 aminoacids residues sequence containing a BTB/POZ (broad complex Tramtrack bric-a-brac/Pox virus and zinc finger) domain in its N-terminal region and kelch motifs in its C-terminal region. Sequence analysis indicates that the rat Nrp/b displays a high level of identity with the equivalent gene orthologs from other organisms. Among rat tissues, Nrp/b expression is more pronounced in brain tissue. We show that overexpression of the Nrp/b cDNA in C6/ST1 cells suppresses anchorage independence in vitro and tumorigenicity in vivo, altering their malignant nature towards a more benign phenotype. Therefore, Nrp/b may be postulated as a novel tumor suppressorgene, with possible relevance for glioblastoma therapy. (C) 2009 Elsevier Ltd. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESPConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPqUniversidade de São Paulo - Pró-Reitoria de Pesquisa PRP-USPUniversidade de São Paulo - Pró-Reitoria de Pesquisa PRP-US

Immunoreactivity of MX35 and Rebmab200 in live cells by flow cytometry.

<p>Immunoreactivity of MX35 and Rebmab200 in live cells by flow cytometry.</p

Global fitted (dotted line) SPR data of murine MX35 and Rebmab200 binding to immobilized synthetic NaPi2b epitope.

<p>MX35 (A) and Rebmab200 (B) were injected at concentrations ranging from 5 to 80 nM. After a 10 min association phase, the dissociation phase was followed for additional 10 min. Following double subtractive referencing, the curves were plotted using a 1∶1 Langmuir binding model, using Biacore T100 Evaluation Software. The solid line represents the experimental data and the dotted line the mathematical model for the binding of MX35 and Rebmab200 to the synthetic NaPi2b epitope.</p

Immunoreactivity of MX35 and Rebmab200 in tumor tissues by immunohistochemistry.

<p>Immunoreactivity of MX35 and Rebmab200 in tumor tissues by immunohistochemistry.</p

Comparison of the immuno-affinity of MX35 (left) at 1/50 dilution and Rebmab200 (right) at 1/100 dilution in parallel reactions using the same buffers and amplification and development conditions.

<p>Serial sections of serous papillary ovary adenocarcinoma (A), clear cell renal carcinoma (B), large cell poorly differentiated carcinoma of the lung (C) and invasive ductal carcinoma of the breast (D). Original magnification = 100×.</p

Comparison of ADCC activity between MX35 and Rebmab200 (stable pool) over a range of mAb concentrations.

<p>The % of cytotoxicity represents antibody-mediated cell lysis measured by release of ⁵¹Cr from labeled ovarian cancer cells (OVCAR-3). Effector cells were obtained from donated human peripheral blood. Rebmab100 was used as a positive control, and Zenapax (Roche) was used as a negative control. The assay was repeated with MCF-7 cells, a NaPi2b negative and Le^Y positive (Rebmab100 antigen) tumor cell line, showing no ADCC results (data not shown).</p

Immunoglobulin HC and LC mRNA levels and productivity of the most representative Rebmab200 clones as determined by RT-qPCR.

<p><b>GAPDH was used as a reference gene.</b> Vector represents PER.C6®cells transfected with mock vector; PER.C6® corresponds to the parental cell. Error bars represent the standard deviation of triplicates. Qp represents specific productivity levels.</p