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dc.contributor.advisorTonissen, Kathryn
dc.contributor.authorBloomfield, Kelly Louiseen_US
dc.date.accessioned2018-01-23T02:27:18Z
dc.date.available2018-01-23T02:27:18Z
dc.date.issued2003en_US
dc.identifier.urihttp://hdl.handle.net/10072/366170
dc.description.abstractThioredoxin is a small ubiquitous oxido-reductase found in all species. The highly conserved active site, which facilitates thioredoxins redox activity, contains two redox active cysteine residues. Thioredoxin has numerous protein substrates to which it donates H+ ions and it can also function as a free radical scavenger. Through these activities thioredoxin is able to influence the redox state of not only its protein targets, but also the entire cellular environment. Thioredoxin has been implicated in many biological functions, and one mechanism by which it influences these functions is through interactions with a number of transcription factors including NF-_B and p53. Thioredoxin also has numerous extracellular biological roles. It has been shown that thioredoxin is actively secreted from a number of normal and transformed cell lines including fibroblasts and activated B and T cells. This study investigates the role of thioredoxin in embryonic implantation and cancer cell metastasis, two physiological functions which rely on the same basic processes. Thioredoxin expression has previously been shown to be increased in many cancers. However it has not yet been established whether this increase is a causative or a side effect of the cancerous phenotype. Similarly thioredoxin expression has previously been shown to be increased during different phases of the oestrus cycle and pregnancy. This thesis describes the role of thioredoxin in embryonic implantation using a marmoset model. A thioredoxin cDNA was isolated and subsequently sequenced. Preliminary antibody experiments indicated that the anti human thioredoxin monoclonal antibodies available in our laboratory would recognise marmoset thioredoxin. Subsequently immunocytochemistry using anti human thioredoxin antibodies was carried out on sectioned marmoset uterus and embryonic tissue. The results indicated that thioredoxin is expressed by cells at the embryonic-maternal interface of early implantation sites. Further studies demonstrated that thioredoxin is also expressed and secreted by cultured blastocysts in vitro. This thesis also describes the role of thioredoxin in cancer cell metastasis. Results of this study indicate that thioredoxin is actively involved in facilitating the invasive phenotype of breast cancer cells. The two cell lines utilised were MCF-7, a well differentiated, relatively non-invasive breast cancer cell line; and MDA-MB-231, a poorly differentiated, highly invasive breast cancer cell line. The cell lines were transfected with thioredoxin sense, antisense and 1SS (encodes thioredoxin with both active cysteine residues mutated to serine residues and is thus redox inactive) constructs. The results demonstrate that when endogenous thioredoxin levels are increased, i.e. transfected with a sense thioredoxin construct, the invasive breast cancer cell line MDA-MB-231 becomes more invasive, conversely when endogenous levels are decreased, i.e. transfected with antisense or 1SS constructs, the invasive capacity of these cells decreases. However, when the endogenous level of thioredoxin was manipulated in the relatively non-invasive cell line MCF-7 very little effect was observed. Results also indicate that thioredoxin has the ability to act as a chemoattractant for actively invading breast cancer cells. Both of these functions appear to be dependent on thioredoxin's redox activity. Additional studies described in this thesis have shown that thioredoxin is involved in the regulation of Sp1 in vitro. Sp1 is a transcription factor known to regulate the transcription of a number of genes whose products are intimately involved in the invasive phenotype. The results in this study suggest that Sp1 DNA binding is regulated by thioredoxin such that when reduced by the enzyme its binding to DNA is facilitated. Results also indicate that Sp1 may regulate the transcription of thioredoxin by binding to Sp1 sites within the thioredoxin promoter.en_US
dc.languageEnglishen_US
dc.publisherGriffith Universityen_US
dc.publisher.placeBrisbaneen_US
dc.rights.copyrightThe author owns the copyright in this thesis, unless stated otherwise.en_US
dc.subject.keywordsthioredoxinen_US
dc.subject.keywordsgenetic transcription factorsen_US
dc.subject.keywordsembryonic implantationen_US
dc.subject.keywordscancer cell metastasisen_US
dc.subject.keywordsmarmoseten_US
dc.subject.keywordsmarmosetsen_US
dc.subject.keywordsphenotypeen_US
dc.subject.keywordsphenotypesen_US
dc.subject.keywordsinvasive phenotypeen_US
dc.subject.keywordsinvasive phenotypesen_US
dc.subject.keywordsSp1en_US
dc.titleInvestigation of the Role of Thioredoxin in the Invasive Phenotype and its Interaction with the Transcription Factor Sp1en_US
dc.typeGriffith thesisen_US
gro.rights.copyrightThe author owns the copyright in this thesis, unless stated otherwise.
gro.hasfulltextFull Text
dc.contributor.otheradvisorClarke, Frank
dc.rights.accessRightsPublicen_US
gro.identifier.gurtIDgu1315273924932en_US
gro.identifier.ADTnumberadt-QGU20031021.120018en_US
gro.source.ADTshelfnoADT0en_US
gro.source.GURTshelfnoGURTen_US
gro.thesis.degreelevelThesis (PhD Doctorate)en_US
gro.thesis.degreeprogramDoctor of Philosophy (PhD)en_US
gro.departmentSchool of Biomolecular and Biomedical Sciencesen_US
gro.griffith.authorMcGrath, Kelly


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