Tong Hung Man Joanna. / "June 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 137-149). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Based on matching analysis between different EBV strains, we found two nucleotide variations in miR-BART21 and four nucleotide changes in miR-BART22. Interestingly, two nucleotide variations upstream of mature miR-BART22 likely favor its biogenesis by Drosha/DGCR8 processing and we experimentally confirmed this augmentation by in-vitro Drosha digestion, and thus may underline the high and consistent expression of miR-BART22 in NPC tumors. / Infection with the Epstein-Barr virus (EBV) is a strong predisposing factor in the development of nasopharyngeal carcinoma (NPC). Many viral gene products including EBNA1, LMP1 and LMP2 have been implicated in NPC tumorigenesis, although the de novo control of these viral oncoproteins remain largely unclear. / MicroRNAs (miRNAs) are a class of small, non-coding RNAs with a size around 18--24 nucleotides with significant roles in regulating gene expression by either transcriptional silencing or translational suppression. As gene regulators, recent miRNA studies have emphasized the contribution of aberrant miRNA expression in cancer development. The recent discovery of EBV encoded viral miRNAs (ebv-miRNAs) in lymphoid malignancies has prompted us to examine the NPC-associated EBV miRNAs. In this study, we have systematically examined the NPC associated EBV genome for viral-encoded miRNA expression. By constructing small cDNA libraries from a native EBV positive NPC cell line (C666-1) and a xenograft (X2117), we screened about 3000 clones and detected several small EBV fragments, within which two novel ebv-miRNAs in the BARTs region were identified. These two newly identified miRNAs, now named miR-BART21 and miR-BART22, were proven to be abundantly expressed in most NPC samples by both Northern blot and QRT-PCR analysis. / Taken together, this thesis shows that two newly identified EBV-encoded miRNAs are highly expressed in latent EBV infection in NPC. Frequent expression of miR-BART22 can be explained partially by a specific EBV strain that is associated with NPC in our locality. Our findings emphasize the role of miR-BART22 in modulating LMP-2A expression. Because LMP-2A is a potent immunogenic viral antigen that is recognized by the cytotoxic T cells (CTLs), down-modulation of LMP-2A expression by mir-BART22 may permit escape of EBV-infected cells from host immune surveillance. / We attempted to predict the potential viral and cellular targets of miR-BART21 and miR-BART22 by public available computer programs, miRanda and RNAhybrid. A number of potential cellular mRNA targets were suggested, although many failed to be validated by luciferase reporter assay. However, we found a putative miR-BART22 binding site in the LMP2A-3'UTR. Although the LMP-2A transcript is consistently detected in NPC, only 6 out of 26 (23%) primary NPC tumors show weak LMP-2A expression by immunohistochemistry (IHC). The expression levels of miR-BART22 and LMP-2A mRNA have also been determined in eleven of these tumors. Interestingly, the LMP-2A mRNA expression level did not directly correlate with protein expression, and relatively low expression levels of miR-BART22 miRNA were observed in all 3 LMP-2A positive-primary tumors. The suppressive effect of miR-BART22 on LMP-2A was also experimentally validated by a series of dual luciferase reporter assays using reporter constructs containing the putative or mutated recognition site at the LMP-2A 3'UTR. By co-transfection of different amounts of miR-BART22 with the LMP-2A-3'UTR expression vector in reporter assay, we confirmed that miR-BART22 suppressed the LMP-2A protein level in a dose-dependent manner. Furthermore, transfection of miR-BART22 into HEK293 cells that had been stably transfected with pcDNA3.1-LMP-2A, which contains a complete LMP-2A ORF and 3'UTR, readily suppressed levels of the LMP-2A protein. / Lung, Wai Ming Raymond. / Adviser: To Ka Fai. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 197-226). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2009.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 3 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 5 uppsatser.

Made available in DSpace on 2015-07-22T20:49:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-24. Added 1 bitstream(s) on 2015-08-11T03:26:30Z : No. of bitstreams: 1 Publico-429a.pdf: 1596515 bytes, checksum: 2107c026687c3e2ecc62f0a5fffa1409 (MD5). Added 1 bitstream(s) on 2015-08-11T03:26:30Z : No. of bitstreams: 2 Publico-429a.pdf: 1596515 bytes, checksum: 2107c026687c3e2ecc62f0a5fffa1409 (MD5) Publico-429b.pdf: 1614171 bytes, checksum: d98715f7a666adc5ceb185cce978000e (MD5). Added 1 bitstream(s) on 2015-08-11T03:26:30Z : No. of bitstreams: 3 Publico-429a.pdf: 1596515 bytes, checksum: 2107c026687c3e2ecc62f0a5fffa1409 (MD5) Publico-429b.pdf: 1614171 bytes, checksum: d98715f7a666adc5ceb185cce978000e (MD5) Publico-429c.pdf: 1500700 bytes, checksum: 77791620b06c9404d28496c4f4ca3dc3 (MD5). Added 1 bitstream(s) on 2015-08-11T03:26:30Z : No. of bitstreams: 4 Publico-429a.pdf: 1596515 bytes, checksum: 2107c026687c3e2ecc62f0a5fffa1409 (MD5) Publico-429b.pdf: 1614171 bytes, checksum: d98715f7a666adc5ceb185cce978000e (MD5) Publico-429c.pdf: 1500700 bytes, checksum: 77791620b06c9404d28496c4f4ca3dc3 (MD5) Publico-429d.pdf: 1826591 bytes, checksum: 70c3dc706cb97372e3f26a7452c01208 (MD5) / O Linfoma de Hodgkin clássico (LHC) é caracterizado pela presença de uma pequena população de células grandes mono ou multinucleadas, denominadas células de Hodgkin-Reed-Sternberg (HRS), circundadas por uma grande massa inflamatória de células não neoplásicas. O vírus Epstein-Barr (EBV) está associado ao Linfoma de Hodgkin em cerca de 50% dos casos. O diagnóstico do LH EBV relacionado é possível por meio da identificação de proteínas virais nas células HRS. Os métodos considerados ideais para essa identificação são as reações de imuno-histoquímica utilizando anticorpos antiproteína latente de membrana (LMP1) e hibridação in situ com uma sonda para o RNA viral (EBER). A LMP-1 é considerada um oncogene clássico. Foi demonstrado que a LMP-1 pode controlar a expressão do gene da metaloproteinase 9 (MMP-9), em linhagem de células C33A. A MMP-9 é um membro da família das endopeptidases que facilita a invasão tumoral e metástases pela degradação do estroma extracelular. Objetivos: avaliar se a expressão da MMP-9 está relacionada ao status do EBV no tumor e se houve impacto na sobrevida livre de eventos (SLE) e sobrevida global (SG) em pacientes com LHC. Casuística e Métodos: foram examinados 97 pacientes com LHC. Todos os pacientes foram submetidos a protocolos de tratamentos equivalentes (MOPPABV ou ABVD). O diagnóstico histopatológico foi revisto e o subtipo classificado de acordo com a OMS. Reações de imuno-histoquímica para LMP-1 e MMP-9 e hibridação in situ para EBER foram realizadas. Resultados: A presença do EBV foi identificada em 52,5% dos casos. Houve uma maior prevalência do subtipo histológico celularidade mista em pacientes EBV positivos (P = 0,005). Não houve diferença na positividade do EBV em relação à faixa etária, sexo, estádio da doença ou pela presença de sintomas B. A presença do EBV no LHC não influenciou a SLE (P = 0,38) ou a SG (P = 0,80) com uma mediana de acompanhamento de 71 meses. A expressão da MMP-9 ocorreu em 87,6% dos casos estudados. Não houve diferença de casos positivos e negativos em relação ao status do EBV (P = 0,59). Quando avaliada a intensidade da expressão da MMP-9 nos casos positivos também não observamos correlação com a presença do EBV (P = 0,62). Não houve diferença entre o resultado da MMP-9 e os parâmetros: subtipo histológico, estádio, presença de sintomas B, idade e sexo. Não houve influência da MMP-9 na SLE (P = 0,98) e SG (P = 0,60). Conclusões: Demonstramos que a prevalência do LH relacionado ao EBV na população estudada é de 52,5%, e que a presença do vírus não altera a evolução clínica, SLE e SG de pacientes tratados uniformemente. Concluímos ainda que a MMP-9 é fortemente expressa nas células HRS. Não há correlação entre a expressão de MMP-9 e o status do EBV. Nem a SG nem a SLE foram influenciadas pela expressão dessa enzima. / Clinical and histological features of classical Hodgkin lymphoma (cHL) are primarily due to the effects of cytokines, enzymes and chemokines produced by Hodgkin-Reed-Sternberg (HRS) cells and their surrounding inflammatory cells in response to signals triggered by etiological factors such as Epstein-Barr virus (EBV). Matrix metalloproteinase-9 (MMP-9) has been associated with poorer survival in patients with aggressive non-Hodgkin lymphomas. In EBV-related cancers the expression of viral latent membrane protein 1 (LMP1) correlates with an increased MMP-9 expression. In this study, we evaluated the prognostic relevance of MMP-9 expression and EBV status in HRS cells in patients with cHL in Brazil. Material and Methods: We selected 97 patients with cHL. Patients were included if they had: 1) > 18 years, 2) Undergone similar chemotherapy protocols, 3) Paraffin blocks available for review and for EBV and MMP-9 detection and 4) Clinical, epidemiological and laboratorial parameters available. Results: EBV was detected in 52.5% of all cases. MMP-9 expression positivity was found in 87.6% of all cases. There was no correlation between MMP-9 expression and EBV status. Response to treatment and relapse rate were independent of MMP-9 expression and EBV status. When stratified according to chemotherapy protocol used or disease stage, we still did not find any difference. MMP-9 positivity did not influence overall survival and event free survival. Conclusion: MMP-9 are expressed in the majority of HRS cells and did not correlated with EBV status or survival. The consistent MMP-9 expression in HRS cells makes this enzyme a potential target for therapy. / TEDE / BV UNIFESP: Teses e dissertações