986 resultados para Proto-oncogene


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New genes contribute substantially to adaptive evolutionary innovation, but the functional evolution of new mammalian genes has been little explored at a broad scale. Previous work established mRNA-derived gene duplicates, known as retrocopies, as models for the study of new gene origination. Here we combine mammalian transcriptomic and epigenomic data to unveil the processes underlying the evolution of stripped-down retrocopies into complex new genes. We show that although some robustly expressed retrocopies are transcribed from preexisting promoters, most evolved new promoters from scratch or recruited proto-promoters in their genomic vicinity. In particular, many retrocopy promoters emerged from ancestral enhancers (or bivalent regulatory elements) or are located in CpG islands not associated with other genes. We detected 88-280 selectively preserved retrocopies per mammalian species, illustrating that these mechanisms facilitated the birth of many functional retrogenes during mammalian evolution. The regulatory evolution of originally monoexonic retrocopies was frequently accompanied by exon gain, which facilitated co-option of distant promoters and allowed expression of alternative isoforms. While young retrogenes are often initially expressed in the testis, increased regulatory and structural complexities allowed retrogenes to functionally diversify and evolve somatic organ functions, sometimes as complex as those of their parents. Thus, some retrogenes evolved the capacity to temporarily substitute for their parents during the process of male meiotic X inactivation, while others rendered parental functions superfluous, allowing for parental gene loss. Overall, our reconstruction of the "life history" of mammalian retrogenes highlights retroposition as a general model for understanding new gene birth and functional evolution.

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Molecular Characteristics of Neuroblastoma with Special Reference to Novel Prognostic Factors and Diagnostic Applications Department of Medical Biochemistry and Genetics Annales Universitatis Turkuensis, Medica-Odontologica, 2009, Turku, Finland Painosalama Oy, Turku, Finland 2009 Background: Neuroblastoma, which is the most common and extensively studied childhood solid cancer, shows a great clinical and biological heterogeneity. Most of the neuroblastoma patients older than one year have poor prognosis despite intensive therapies. The hallmark of neuroblastoma, biological heterogeneity, has hindered the discovery of prognostic tumour markers. At present, few molecular markers, such as MYCN oncogene status, have been adopted into clinical practice. Aims: The aim of the study was to improve the current prognostic methodology of neuroblastoma, especially by taking cognizance of the biological heterogeneity of neuroblastoma. Furthermore, unravelling novel molecular characteristics which associate with neuroblastoma tumour progression and cell differentiation was an additional objective. Results: A new strictly defined selection of neuroblastoma tumour spots of highest proliferation activity, hotspots, appeared to be representative and reliable in an analysis of MYCN amplification status using a chromogenic in situ hybridization technique (CISH). Based on the hotspot tumour tissue microarray immunohistochemistry and high-resolution oligo-array-based comparative genomic hybridization, which was integrated with gene expression and in silico analysis of existing transcriptomics, a polysialylated neural cell adhesion molecule (NCAM) and poorly characterized amplicon at 12q24.31 were discovered to associate with outcome. In addition, we found that a previously considered new neuroblastoma treatment target, the mutated c-kit receptor, was not mutated in neuroblastoma samples. Conclusions: Our studies indicate polysialylated NCAM and 12q24.31 amplicon to be new molecular markers with important value in prognostic evaluation of neuroblastoma. Moreover, the presented hotspot tumour tissue microarray method together with the CISH technique of the MYCN oncogene copy number is directly applicable to clinical use. Key words: neuroblastoma, polysialic acid, neural cell adhesion molecule, MYCN, c-kit, chromogenic in situ hybridization, hotspot

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Invasive malignant melanoma (MM) is an aggressive tumor with no curative therapy available in advanced stages. Nuclear corepressor (NCoR) is an essential regulator of gene transcription, and its function has been found deregulated in different types of cancer. In colorectal cancer cells, loss of nuclear NCoR is induced by Inhibitor of kappa B kinase (IKK) through the phosphorylation of specific serine residues. We here investigate whether NCoR function impacts in MM, which might have important diagnostic and prognostic significance. By IHC, we here determined the subcellular distribution of NCoR in a cohort of 63 primary invasive MM samples, and analyzed its possible correlation with specific clinical parameters. We therefore used a microarray-based strategy to determine global gene expression differences in samples with similar tumor stage, which differ in the presence of cytoplasmic or nuclear NCoR. We found that loss of nuclear NCoR results in upregulation of a specific cancer-related genetic signature, and is significantly associated with MM progression. Inhibition of IKK activity in melanoma cells reverts NCoR nuclear distribution and specific NCoR-regulated gene transcription. Analysis of public database demonstrated that inactivating NCoR mutations are highly prevalent in MM, showing features of driver oncogene.

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The present thesis investigated the importance of semantics in generating inferences during discourse processing. Three aspects of semantics, gender stereotypes, implicit causality information and proto-role properties, were used to investigate whether semantics is activated elaboratively during discourse comprehension and what its relative importance is in backward inferencing compared to discourse/structural cues. Visual world eye-tracking studies revealed that semantics plays an important role in both backward and forward inferencing: Gender stereotypes and implicit causality information is activated elaboratively during online discourse comprehension. Moreover, gender stereotypes, implicit causality and proto-role properties of verbs are all used in backward inferencing. Importantly, the studies demonstrated that semantic cues are weighed against discourse/structural cues. When the structural cues consist of a combination of cues that have been independently shown to be important in backward inferencing, semantic effects may be masked, whereas when the structural cues consist of a combination of fewer prominent cues, semantics can have an earlier effect than structural factors in pronoun resolution. In addition, the type of inference matters, too: During anaphoric inferencing semantics has a prominent role, while discourse/structural salience attains more prominence during non-anaphoric inferencing. Finally, semantics exhibits a strong role in inviting new inferences to revise earlier made inferences even in the case the additional inference is not needed to establish coherence in discourse. The findings are generally in line with the Mental Model approaches. Two extended model versions are presented that incorporate the current findings into the earlier literature. These models allow both forward and backward inferencing to occur at any given moment during the course of processing; they also allow semantic and discourse/structural cues to contribute to both of these processes. However, while the Mental Model 1 does not assume interactions between semantic and discourse/structural factors in forward inferencing, the Mental Model 2 does assume such a link.

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ABSTRACT 'The Duologue of King/Governor Pāyāsi' ("Long Discourses") has long been recognised as a source for the proto-materialism current at the time of the Buddha. What needs to be stressed is the significance of the text as a pointer to the development of Logic in India. Perception (observation and experiment employing the joint method of agreement and difference), which is an accepted method of experimental enquiry, and reasoning from analogy, which can lead at best to a probable conclusion - these two are the only means employed to settle the dispute concerning the existence of the other-world. The Jain version of the same duologue-cum-parable, though varying in minor details regarding the name and identity of the monk refuting the king/governor, contains the same contrast, namely, perception versus analogical reasoning. There can be little doubt that the original parable was conceived with a view to asserting the existence of the other-world. In the Kaṭha Upaniṣad (sixth century BCE), an earlier Brahmanical text, however, instead of argument by analogy, verbal testimony (śabda) was invoked to settle the same point. Naciketas is assailed by doubt about the existence of a person after his or her death. The authority of Yama, the Pluto of Indian mythology, is invoked to convince him that the other-world does exist. Thus, the three parables taken together exhibit three means of knowledge in operation: verbal testimony and argument by analogy pitted against perception.

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Työn tarkoituksena oli selvittää Proto 10 kemikaalisekoittimen kyky dispergoida kaasua keskisakean valkaistun mäntysellun joukkoon. Työssä käytettiin kuvantamistekniikkaa, jonka avulla pystyttiin näkemään sekoittimen ja putkiston sisälle sekoitustapahtuman aikana. Muodostunutta dispersiota tarkasteltiin kolmesta kuvauspisteestä, joista yksi sijaitsi sekoittimen pesässä ja kaksi putkistossa sekoittimen jälkeen. Työssä verrattiin myös laboratoriosekoittimella saatuja tuloksia teollisen mittakaavan sekoittimella saatuihin tuloksiin, sekä määritettiin tarvittava pinta-aktiivisen aineen konsentraatio, jolla saavutettiin ruskeaa massaa vastaava vaahtoaminen. Työn kokeellinen osuus koostui kolmesta osasta. Ensimmäisessä vaiheessa tutkittiin ruskeasta mänty- ja koivumassasta lingotun suodoksen vaahtoamista ja verrattiin sitä vedellä ja pesuaineella saatavaan vaahtoon. Toisessa vaiheessa suoritettiin referenssiajot laboratoriosekoittimen ja teollisen mittakaavan sekoittimen vertailua varten Quantum Mark IV laboratoriosekoittimella. Kolmannessa vaiheessa tutkittiin Proto 10 sekoittimen kykyä dispergoida kaasua mäntysellun joukkoon eri pyörimisnopeuksilla ja virtaamilla. Työn tuloksien perusteella energiankäytön kannalta paras pyörimisnopeus Proto 10 sekoittimelle on 1500 min-1. Nostamalla kierrosnopeutta yli tämän ei saavutettu merkittävää parannusta dispersion laadussa varsinkaan suuremmilla virtaamilla. Virtaamalla todettiin olevan suuri merkitys sekoitustulokseen. Laboratoriosekoittimella tehtyjen kokeiden todettiin vastaavan parhaiten teollisen mittakaavan tuloksia pyörimisnopeudella 1200 min-1.

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TMPRSS2–ERG is the most frequent type of genomic rearrangement present in prostate tumors, in which the 5- prime region of the TMPRSS2 gene is fused to the ERG oncogene. TMPRSS2, containing androgen response elements (AREs), is regulated by androgens in the prostate. The truncated TMPRSS2-ERG fusion transcript is overexpressed in half of the prostate cancer patients. The formation of TMPRSS2-ERG transcript is an early event in prostate carcinogenesis and previous in vivo and in vitro studies have shown ectopic ERG expression to be associated with increased cell invasion. However, the molecular function of ERG and its role in cell signaling is poorly understood. In this study, genomic rearrangement of ERG with TMPRSS2 was studied by using comparative genomic hybridization (CGH) in prostate cancer samples. The biological processes associated with the ERG oncogene expression in prostate epithelial cells were studied, and the results were compared with findings observed in clinical prostate tumor samples. The gene expression data indicated that increased WNT signaling and loss of cell adhesion were a characteristic of TMPRSS2- ERG fusion positive prostate tumor samples. Up- regulation of WNT pathway genes were present in ERG positive prostate tumors, with frizzled receptor 4 (FZD4) presenting with the highest association with ERG overexpression, as verified by quantitative reverse transcription-PCR, immunostaining, and immunoblotting in TMPRSS2-ERG positive VCaP prostate cancer cells. Furthermore, ERG and FZD4 silencing increased cell adhesion by inducing active β1-integrin and E-cadherin expression in VCaP cells. Furthermore, we found a novel inhibitor, 4-(chloromethyl) benzoyl chloride which inhibited the WNT signaling and induced similar phenotypic effects as observed after ERG or FZD4 down regulation in VCaP cells. In conclusion, this work deepens our understanding on the complex oncogenic mechanisms of ERG in prostate cancer that may help in developing drugs against TMPRSS2-ERG positive tumors.

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Prostate cancers form a heterogeneous group of diseases and there is a need for novel biomarkers, and for more efficient and targeted methods of treatment. In this thesis, the potential of microarray data, RNA interference (RNAi) and compound screens were utilized in order to identify novel biomarkers, drug targets and drugs for future personalized prostate cancer therapeutics. First, a bioinformatic mRNA expression analysis covering 9873 human tissue and cell samples, including 349 prostate cancer and 147 normal prostate samples, was used to distinguish in silico prevalidated putative prostate cancer biomarkers and drug targets. Second, RNAi based high-throughput (HT) functional profiling of 295 prostate and prostate cancer tissue specific genes was performed in cultured prostate cancer cells. Third, a HT compound screen approach using a library of 4910 drugs and drug-like molecules was exploited to identify potential drugs inhibiting prostate cancer cell growth. Nine candidate drug targets, with biomarker potential, and one cancer selective compound were validated in vitro and in vivo. In addition to androgen receptor (AR) signaling, endoplasmic reticulum (ER) function, arachidonic acid (AA) pathway, redox homeostasis and mitosis were identified as vital processes in prostate cancer cells. ERG oncogene positive cancer cells exhibited sensitivity to induction of oxidative and ER stress, whereas advanced and castrate-resistant prostate cancer (CRPC) could be potentially targeted through AR signaling and mitosis. In conclusion, this thesis illustrates the power of systems biological data analysis in the discovery of potential vulnerabilities present in prostate cancer cells, as well as novel options for personalized cancer management.

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Neurofibromatosis type 1 (NF1) is an autosomal dominant cancer predisposition syndrome that affects about 1 in 3500 individuals worldwide. NF1 is caused by mutations in the NF1 gene that encodes the tumor suppressor protein neurofibromin, an inactivator of the Ras oncogene. The hallmarks of NF1 include pigmentary lesions of the skin, Lisch nodules of the iris and cutaneous neurofibromas. Cutaneous neurofibromas are benign tumors composed of all the cell types of normal peripheral nerve. The traditional view of neurofibroma development has been that cutaneous neurofibromas arise from the disruption of the small nerve tributaries of the skin and subsequent proliferation of the resident cells. The second hit mutation in the NF1 gene has been considered as a prerequisite for neurofibroma development. The second hit is detectable in a subpopulation of primary Schwann cells cultured from neurofibromas. This thesis challenges the traditional concept of neurofibroma development. The results show that cutaneous neurofibromas are intimately associated with hair follicular structures and contain multipotent precursor cells (NFPs), suggesting that neurofibromas may arise from the multipotent cells which reside in hair follicles. Furthermore, this study presents that neurofibroma-derived Schwann cells that harbor bi-allelic inactivation in the NF1 gene express HLA class II genes and may act as nonprofessional antigen presenting cells. The CD4- and FoxP3-positive cells detected in cutaneous neurofibromas suggest that these cells may represent regulatory T cells (Tregs) which interact with HLA II –positive cells and aid the tumor cells in hiding from the immune system and are thus mediators of immune tolerance. This thesis also investigated neurofibroma development in the oral cavity and the use of different biomarkers to characterize cellular differentiation in neurofibromas. The results revealed that oral neurofibromas are not rare, but they usually appear as solitary lesions contrary to multiple cutaneous neurofibromas and present high heterogeneity within and between tumors. The use of class III beta-tubulin as a marker for neuronal differentiation led to an unexpected finding showing that multiple cell types express class III beta-tubulin during mitosis. The increased understanding of the multipotency of tumor cells, cellular differentiation and ability to hide from immune system will aid in the development of future treatments. Specifically, targeting Tregs in NF1 patients could provide a novel therapeutic approach to interfere with the development of neurofibromas.

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OBJETIVO: Avaliar a frequência da mutação V600E do gene BRAF em pacientes com mais de 65 anos de idade submetidos à tireoidectomia, correlacionando sua presença ou ausência com as diferentes lesões histológicas, com as variantes e com fatores prognósticos do carcinoma papilífero. MÉTODOS: Foram avaliados 85 pacientes com mais de 65 anos de idade submetidos à tireoidectomia, analisando a mutação BRAF V600E através de reação de PCR-RT realizada após a extração do DNA dos blocos de parafina. RESULTADOS: Detectou-se ausência ou presença da mutação BRAF V600E em 47 pacientes (55,3%). Entre os 17 carcinomas papilíferos estudados, sete apresentavam a mutação (41,2%). Demonstrou-se associação estatística entre a presença desta mutação e a variante clássica do carcinoma papilífero, além de tendência de associação com o extravasamento tireoideano. CONCLUSÃO: A mutação BRAF nos pacientes idosos também é exclusiva do carcinoma papilífero e tem frequência expressiva. Além disso, está relacionada à variante clássica e, possivelmente, ao extravasamento tireoideano.

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OBJETIVO: Comparar a expressão gênica (mRNA) e protéica dos protooncogenes c-fos, c-myc e c-jun em miométrio normal e mioma humanos. MÉTODOS: Foi realizado um estudo do tipo caso-controle. O material foi coletado de 12 pacientes submetidas a histerectomia no Hospital de Clínicas de Porto Alegre. A expressão do mRNA específico para c-myc, c-fos, c-jun e beta-microglobulina foi avaliada pela técnica de RT-PCR, utilizando primers específicos para cada gene. A expressão protéica destes protooncogenes foi avaliada através de Western blot com anticorpos específicos. RESULTADOS: Não houve diferença significativa para expressão gênica desses protooncogenes entre miométrio normal e mioma (c-myc: 0,87 ± 0,08 vs 0,87 ± 0,08, p = 0,952; c-fos: 1,10 ± 0,17 vs 1,01 ± 0,11, p = 0,21; c-jun: 1,03 ± 0,12 vs 0,96 ± 0,09, p = 0,168, respectivamente). Não houve diferença significativa para expressão protéica desses protooncogenes entre miométrio normal e mioma (c-myc: 1,36 ± 0,48 vs 1,53 ± 0,29, p = 0,569; c-fos: 8,85 ± 5,5 vs 6,56 ± 4,22, p = 0,434; e c-jun: 6,47 ± 3,04 vs 5,42 ± 2,03, p = 0,266, respectivamente). CONCLUSÃO: A expressão gênica (transcrição) e a expressão protéica (tradução) dos protooncogenes c-myc, c-fos e c-jun em mioma e miométrio normal são semelhantes.

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PURPOSE: To examine the expression of AKT and PTEN in a series of HER2-positive primary invasive breast tumors using immunohistochemistry, and to associate these expression profiles with classic pathologic features such as tumor grade, hormone receptor expression, lymphatic vascular invasion, and proliferation.METHODS: A total of 104 HER2-positive breast carcinoma specimens were prepared in tissue microarrays blocks for immunohistochemical detection of PTEN and phosphorylated AKT (pAKT). Original histologic sections were reviewed to assess pathological features, including HER2 status and Ki-67 index values. The associations between categorical and numeric variables were identified using Pearson's chi-square test and the Mann-Whitney, respectively.RESULTS: Co-expression of pAKT and PTEN was presented in 59 (56.7%) cases. Reduced levels of PTEN expression were detected in 20 (19.2%) cases, and these 20 tumors had a lower Ki-67 index value. In contrast, tumors positive for pAKT expression [71 (68.3%)] were associated with a higher Ki-67 index value.CONCLUSION: A role for AKT in the proliferation of HER2-positive breast cancers was confirmed. However, immunohistochemical detection of PTEN expression did not correlate with an inhibition of cellular proliferation or control of AKT phosphorylation, suggesting other pathways in these mechanisms of control.

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The integrin family of transmembrane receptors are important for cell-matrix adhesion and signal transmission to the interior of the cell. Integrins are essential for many physiological processes and defective integrin function can consequently result in a multitude of diseases, including cancer. Integrin traffic is needed for completion of cytokinesis and cell division failure has been proposed to be an early event in the formation of chromosomally aberrant and transformed cells. Impaired integrin traffic and changes in integrin expression are known to promote invasion of malignant cells. However, the direct roles of impaired integrin traffic in tumorigenesis and increased integrin expression in oncogene driven invasion have not been examined. In this study we have investigated both of these aspects. We found that cells with reduced integrin endocytosis become binucleate and subsequently aneuploid. These aneuploid cells display characteristics of transformed cells; they are anchorage-independent, resistant to apoptosis and invasive in vitro. Importantly, subcutaneous injection of the aneuploid cells into athymic nude mice produced highly malignant tumors. Through gene expression profiling and analysis of integrin-triggered signaling pathways we have identified several molecules involved in the malignancy of these cells, including Src kinase and the transcription factor Twist2. Thus, even though chromosomal aberrations are associated with reduced cell fitness, we show that aneuploidy can facilitate tumor evolution and selection of transformed cells. Invasion and metastasis are the primary reason for deaths caused by cancer and the molecular pathways responsible for invasion are therefore attractive targets in cancer therapy. In addition to integrins, another major family of adhesion receptors are the proteoglycans syndecans. Integrins and syndecans are known to signal in a synergistic manner in controlling cell adhesion on 2D matrixes. Here we explored the role of syndecans as α2β1 integrin co-receptors in 3D collagen. We show that in breast cancer cells harbouring mutant K-Ras, increased levels of integrins, their co-receptors syndecans and matrix cleaving proteases are necessary for the invasive phenotype of these cells. Together, these findings increase our knowledge of the complicated changes that occur during tumorigenesis and the pathways that control the ability of cancer cells to invade and metastasize.

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O objetivo do presente trabalho foi selecionar genótipos de cana-de-açúcar por meio de inibidores da PROTOX e antioxidantes para indução do acúmulo de protoporfirina IX (PROTO IX) e/ou de seus precursores em plantas. Esses compostos podem ser utilizados como agentes sensibilizantes em terapia fotodinâmica (TFD), os quais possibilitam uma fonte de baixo custo para o tratamento de neoplasias e carcinomas. O experimento foi montado em câmara climatizada, com aplicação de nove tratamentos (1. oxyfluorfen + glutamato monossódico + vitaminas C e E; 2. oxyfluorfen + glutamato monossódico + vitaminas C e E + ácido levulênico; 3. oxyfluorfen; 4. carfentrazone + glutamato monossódico + vitaminas C e E; 5. carfentrazone + glutamato monossódico + vitaminas C e E + ácido levulênico; 6. carfentrazone; 7. testemunha + vitaminas C e E; 8. testemunha + vitaminas C e E + ácido levulênico; e 9. testemunha) em oito genótipos de cana-de-açúcar (PO933499, RB806043, RB470355, PO830698, SP701143, PO901387, PO894414 e SP903414), dispostos em esquema fatorial 9 x 8, com quatro repetições. As repetições constituíram-se de folhas (20 cm) destacadas de cada genótipo, sendo estas pulverizadas com os tratamentos mencionados, em simulador estacionário. Foram realizadas avaliações visuais de controle aos 2 DAA (dias após aplicação) e, no fim do estudo, determinações analíticas via extração da biomassa fresca, verificando os teores de protoporfirina IX por cromatografia líquida de alta eficiência. Os resultados mostraram que em curto prazo foram detectados aumentos significativos nas concentrações de PROTO IX para os genótipos RB470355 e SP903414 submetidos ao tratamento 2 e para o genótipo SP701143 submetido ao tratamento 8, indicando que eles podem ser utilizados como fontes acumuladoras de protoporfirina IX.