Ko Chun-wai, Hardy. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 107-132). / Acknowledgement --- p.3 / Declaration of originality --- p.4 / Summary of thesis --- p.5-6 / Chapter Chapter 1 --- Introduction and aims of study --- p.7-26 / Chapter Chapter 2 --- Materials and methods --- p.27-39 / Chapter Chapter 3 --- Results of study --- p.40-77 / Chapter Chapter 4 --- Discussion --- p.78-103 / Chapter Chapter 5 --- Conclusion of study --- p.104-106 / References --- p.107-132

Glioblastomas Multiformes (GBM) são tumores do Sistema Nervoso Central com altas taxas de invasibilidade e grande resistência a quimio e radioterapias, cuja origem foi inicialmente atribuída a células tronco neurais (NSCs). Mais recentemente, trabalhos de rastreamento de linhagem celular (lineage tracing) revelaram que a célula de origem em GBM, ao menos para certos subtipos, é na verdade a célula precursora de oligodendrócitos (OPC). A identificação da origem do tumor pode auxiliar na compreensão da doença e no desenvolvimento de terapias mais eficazes. OPCs são células com grande capacidade migratória e constituem a população de células cerebrais mais proliferativamente ativa, características compatíveis com a biologia de glioblastomas. Neste trabalho criamos uma meta-assinatura de OPCs que, quando aplicada a amostras populacionais e de céulas únicas de GBMs humanos, indica a presença de características de OPCs em virtualmente todos os tumores, principalmente dentre os do subtipo Proneural. Apesar disso, o cultivo de GBMs in vitro tem sido tradicionalmente realizado em meio próprio de NSCs, como forma de preservar as características originais do tumor. Entretanto, no caso de OPC ser a verdadeira célula de origem, o ideal seria a utilização de meio próprio para esta célula. Utilizamos meio padrão para NSCs e meio para OPCs em linhagens de camundongo bem como em biópsias humanas. Meio de NSCs provoca alterações morfológicas e em marcadores, enquanto meio de OPCs mantém as células mais similares ao tumor que lhes deu origem. Principalmente, meio de NSCs reduz o potencial tumorigênico das células in vivo, e faz com que alvos errôneos sejam identificados na resposta a drogas, devido à expressão de marcadores nãoautênticos pra célula de origem. A análise de gliomas humanos indica que a população proliferativamente ativa expressa marcadores de OPCs, independentemente do subtipo em que o tumor foi classificado. Assim, concluímos que o papel de OPCs no desenvolvimento de GBMs é mais importante do que se imaginava, e que a utilização de meio de cultivo baseado na célula de origem é fundamental para a correta identificação de alvos terapêuticos. / Glioblastoma Multiformes (GBM) are Central Nervous System tumors that present high invasibility rates and great resistance to chemo- and radiotherapies, whose origin was initially accredited to Neural Stem Cells (NSCs). More recently, papers employing lineage tracing revealed that the cell of origin in GBM, at least for certain subtypes, is in fact an Oligodendrocyte Precursor Cell (OPC). The elucidation about the origin of a tumor can help in the disease comprehension and in the development of more efficient therapies. OPCs are naturally migratory cells and constitute the most actively proliferating cell population in the brain, characteristics that are compatible with glioblastoma biology. In this work we created an OPC meta-signature that, once applied to populational and single-cell data in GBM, reveals the presence of OPC features in virtually every tumor, mainly from the Proneural subtype. Moreover, GBM in vitro culture has traditionally been done in NSC media, as an attempt to preserve original characteristics from the tumor. However, if OPC is the real cell of origin, it would be better to grow GBM samples in OPC media. Here, we used NSC media and OPC media in mice lines as well as in human byopsies. NSC media induces morphological and marker changes, while OPC media maintains the cells more similar to the tumor from where they were originated. Mainly, NSC media reduces the tumorigenic potential of the cells in vivo, and causes false targets to be identified in response to drugs due to the expression of non-authentic markers to the cell of origin. Human glioma analysis indicates that the actively proliferating population expresses OPC markers, regardless of the subtype in which the tumor was classified. Therefore, we conclude that the role of OPCs in GBM development is more importante than originally thought, and that the employment of culture media based on cell of origin is of fundamental importance for the correct identification of therapeutical targets.

Glioblastomas Multiformes (GBM) são tumores do Sistema Nervoso Central com altas taxas de invasibilidade e grande resistência a quimio e radioterapias, cuja origem foi inicialmente atribuída a células tronco neurais (NSCs). Mais recentemente, trabalhos de rastreamento de linhagem celular (lineage tracing) revelaram que a célula de origem em GBM, ao menos para certos subtipos, é na verdade a célula precursora de oligodendrócitos (OPC). A identificação da origem do tumor pode auxiliar na compreensão da doença e no desenvolvimento de terapias mais eficazes. OPCs são células com grande capacidade migratória e constituem a população de células cerebrais mais proliferativamente ativa, características compatíveis com a biologia de glioblastomas. Neste trabalho criamos uma meta-assinatura de OPCs que, quando aplicada a amostras populacionais e de céulas únicas de GBMs humanos, indica a presença de características de OPCs em virtualmente todos os tumores, principalmente dentre os do subtipo Proneural. Apesar disso, o cultivo de GBMs in vitro tem sido tradicionalmente realizado em meio próprio de NSCs, como forma de preservar as características originais do tumor. Entretanto, no caso de OPC ser a verdadeira célula de origem, o ideal seria a utilização de meio próprio para esta célula. Utilizamos meio padrão para NSCs e meio para OPCs em linhagens de camundongo bem como em biópsias humanas. Meio de NSCs provoca alterações morfológicas e em marcadores, enquanto meio de OPCs mantém as células mais similares ao tumor que lhes deu origem. Principalmente, meio de NSCs reduz o potencial tumorigênico das células in vivo, e faz com que alvos errôneos sejam identificados na resposta a drogas, devido à expressão de marcadores nãoautênticos pra célula de origem. A análise de gliomas humanos indica que a população proliferativamente ativa expressa marcadores de OPCs, independentemente do subtipo em que o tumor foi classificado. Assim, concluímos que o papel de OPCs no desenvolvimento de GBMs é mais importante do que se imaginava, e que a utilização de meio de cultivo baseado na célula de origem é fundamental para a correta identificação de alvos terapêuticos. / Glioblastoma Multiformes (GBM) are Central Nervous System tumors that present high invasibility rates and great resistance to chemo- and radiotherapies, whose origin was initially accredited to Neural Stem Cells (NSCs). More recently, papers employing lineage tracing revealed that the cell of origin in GBM, at least for certain subtypes, is in fact an Oligodendrocyte Precursor Cell (OPC). The elucidation about the origin of a tumor can help in the disease comprehension and in the development of more efficient therapies. OPCs are naturally migratory cells and constitute the most actively proliferating cell population in the brain, characteristics that are compatible with glioblastoma biology. In this work we created an OPC meta-signature that, once applied to populational and single-cell data in GBM, reveals the presence of OPC features in virtually every tumor, mainly from the Proneural subtype. Moreover, GBM in vitro culture has traditionally been done in NSC media, as an attempt to preserve original characteristics from the tumor. However, if OPC is the real cell of origin, it would be better to grow GBM samples in OPC media. Here, we used NSC media and OPC media in mice lines as well as in human byopsies. NSC media induces morphological and marker changes, while OPC media maintains the cells more similar to the tumor from where they were originated. Mainly, NSC media reduces the tumorigenic potential of the cells in vivo, and causes false targets to be identified in response to drugs due to the expression of non-authentic markers to the cell of origin. Human glioma analysis indicates that the actively proliferating population expresses OPC markers, regardless of the subtype in which the tumor was classified. Therefore, we conclude that the role of OPCs in GBM development is more importante than originally thought, and that the employment of culture media based on cell of origin is of fundamental importance for the correct identification of therapeutical targets.

Glioblastomas Multiformes (GBM) são tumores do Sistema Nervoso Central com altas taxas de invasibilidade e grande resistência a quimio e radioterapias, cuja origem foi inicialmente atribuída a células tronco neurais (NSCs). Mais recentemente, trabalhos de rastreamento de linhagem celular (lineage tracing) revelaram que a célula de origem em GBM, ao menos para certos subtipos, é na verdade a célula precursora de oligodendrócitos (OPC). A identificação da origem do tumor pode auxiliar na compreensão da doença e no desenvolvimento de terapias mais eficazes. OPCs são células com grande capacidade migratória e constituem a população de células cerebrais mais proliferativamente ativa, características compatíveis com a biologia de glioblastomas. Neste trabalho criamos uma meta-assinatura de OPCs que, quando aplicada a amostras populacionais e de céulas únicas de GBMs humanos, indica a presença de características de OPCs em virtualmente todos os tumores, principalmente dentre os do subtipo Proneural. Apesar disso, o cultivo de GBMs in vitro tem sido tradicionalmente realizado em meio próprio de NSCs, como forma de preservar as características originais do tumor. Entretanto, no caso de OPC ser a verdadeira célula de origem, o ideal seria a utilização de meio próprio para esta célula. Utilizamos meio padrão para NSCs e meio para OPCs em linhagens de camundongo bem como em biópsias humanas. Meio de NSCs provoca alterações morfológicas e em marcadores, enquanto meio de OPCs mantém as células mais similares ao tumor que lhes deu origem. Principalmente, meio de NSCs reduz o potencial tumorigênico das células in vivo, e faz com que alvos errôneos sejam identificados na resposta a drogas, devido à expressão de marcadores nãoautênticos pra célula de origem. A análise de gliomas humanos indica que a população proliferativamente ativa expressa marcadores de OPCs, independentemente do subtipo em que o tumor foi classificado. Assim, concluímos que o papel de OPCs no desenvolvimento de GBMs é mais importante do que se imaginava, e que a utilização de meio de cultivo baseado na célula de origem é fundamental para a correta identificação de alvos terapêuticos. / Glioblastoma Multiformes (GBM) are Central Nervous System tumors that present high invasibility rates and great resistance to chemo- and radiotherapies, whose origin was initially accredited to Neural Stem Cells (NSCs). More recently, papers employing lineage tracing revealed that the cell of origin in GBM, at least for certain subtypes, is in fact an Oligodendrocyte Precursor Cell (OPC). The elucidation about the origin of a tumor can help in the disease comprehension and in the development of more efficient therapies. OPCs are naturally migratory cells and constitute the most actively proliferating cell population in the brain, characteristics that are compatible with glioblastoma biology. In this work we created an OPC meta-signature that, once applied to populational and single-cell data in GBM, reveals the presence of OPC features in virtually every tumor, mainly from the Proneural subtype. Moreover, GBM in vitro culture has traditionally been done in NSC media, as an attempt to preserve original characteristics from the tumor. However, if OPC is the real cell of origin, it would be better to grow GBM samples in OPC media. Here, we used NSC media and OPC media in mice lines as well as in human byopsies. NSC media induces morphological and marker changes, while OPC media maintains the cells more similar to the tumor from where they were originated. Mainly, NSC media reduces the tumorigenic potential of the cells in vivo, and causes false targets to be identified in response to drugs due to the expression of non-authentic markers to the cell of origin. Human glioma analysis indicates that the actively proliferating population expresses OPC markers, regardless of the subtype in which the tumor was classified. Therefore, we conclude that the role of OPCs in GBM development is more importante than originally thought, and that the employment of culture media based on cell of origin is of fundamental importance for the correct identification of therapeutical targets.

Receptor tyrosine kinases (RTKs) constitute a family of proteins controlling cell growth and proliferation and whose activities are tightly controlled in normal cells. LRIG1 is a negative regulator of RTK signaling and is a proposed tumor suppressor. The aim of this thesis was to identify and study possible paralogs of LRIG1. By using the basic local alignment search tool and cDNA cloning, a human mRNA sequence with similarity to LRIG1 was identified and named LRIG2. By fluorescence in situ hybridization analysis, LRIG2 was found to reside on chromosome 1p13. The LRIG2 amino acid sequence was 47% identical to LRIG1, and the predicted protein domain organization was the same as that of LRIG1. Antibodies against LRIG2 were developed and the apparent molecular weight of the protein was determined to be 132 kDa by SDS-polyacrylamide gel electrophoresis and Western blot analysis. The sub-cellular localization was studied by cell surface biotinylation experiments and confocal fluorescence laser microscopy, which revealed that LRIG2 resided at the cell surface and in the cytoplasm. The expression patterns of LRIG2 mRNA, during development and in adult tissues, were evaluated using whole-mount in situ hybridization and quantitative real-time RT-PCR, respectively. In E10.5, E11.5 and E12.5 mouse embryos, the Lrig2 expression domains were both overlapping and unique as compared to the expression domains of Lrig1 and the third family member, Lrig3. In adult human tissues, the most prominent LRIG2 mRNA expression was found in skin, uterus and ovary. To study the developmental and physiological role of LRIG2, Lrig2 knock-out mice were generated. The knock-out mice were born at Mendelian frequencies without any apparent morphological abnormalities. However, Lrig2 knock-out mice showed reduced body weight between 5 days and 12-15 weeks of age, increased mortality, and impaired reproductive capacity. To study the role of LRIG2 as a prognostic factor in oligodendroglioma, LRIG2 expression was analyzed in 65 human oligodendrogliomas by immunohistochemistry. Cytoplasmic LRIG2 expression was an independent prognostic factor associated with poor oligodendroglioma patient survival. The possible functional role of LRIG2 in oligodendroglioma biology was further investigated using the RCAS/tv-a mouse model. Tumors resembling human oligodendroglioma were induced by intracranial injection of PDGFB carrying RCAS retroviruses into newborn Ntv-a mice. Lrig2 wild-type animals developed tumors at a higher frequency and of higher malignancy than the Lrig2 knock-out mice. This result supports the notion that LRIG2 promotes PDGF-induced oligodendroglioma genesis. A possible molecular mechanism was revealed as LRIG2 overexpression increased PDGFRa levels in transfected cells. In summary, we identified a new gene named LRIG2, showed that it is expressed in a variety of tissues during development and in adulthood, knocked it out and found that it was required for proper animal growth, health, and reproduction. We also found that Lrig2 expression promoted PDGF-induced oligodendroglioma genesis and was associated with poor oligodendroglioma patient survival, possibly via a PDGFRa stabilizing function.

Diss. (sammanfattning) Umeå : Umeå universitet, 2010.

Dong Zhiqian. / "June 2003." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2003. / 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.

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

Previous studies of human oligodendroglial neoplasms have demonstrated the diagnostic and prognostic values of histomorphologic features and immunocytochemical markers. Primary spontaneous canine intracranial tumors share many of the biologic behaviors and pathologic features of their human counterparts. The objectives of this study were to determine if associations existed between five histomorphologic features (mitoses, cellular atypia, necrosis, vascular hypertrophy, and vascular proliferation), and three immunocytochemical markers (GFAP, EGFR, and Ki-67 labeling index) and the degree of malignancy, as defined by WHO grading criteria, of 15 canine oligodendroglial tumors. Of the histomorphologic variables examined, mitoses and cellular atypia were significantly greater in Grade III oligodendrogliomas than in Grade II oligodendrogliomas (p = 0.002, and p = 0.004, respectively), but no differences were noted between these features and Grade II oligoastrocytomas and Grade II or Grade III oligodendrogliomas. No significant associations were found between GFAP or EGFR immunoreactivity and tumor type or grade. The median percentage of Ki-67 immunoreactivity was significantly different between all tumor types and grades (p < 0.05), and was significantly higher in Grade III oligodendrogliomas than in both oligoastrocytomas (p = 0.014) and Grade II oligodendrogliomas (p = 0.006). Results of this study indicate that although mitoses and cellular atypia are useful histomorphologic features for the differentiation of tumors with oligodendroglial phenotypes, none of the variables examined reliably distinguished mixed gliomas from oligodendrogliomas. The presence of GFAP immunoreactivity in all tumor types suggests that oligodendroglial tumors may arise from a common multipotential cellular lineage. Similar to what has been demonstrated in humans, the Ki-67 labeling index correlated well with the degree of malignancy in the tumors studied. / Master of Science

Dong Shumin. / "February 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 187-220). / 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.