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dc.contributor.advisorGamero, Ana
dc.creatorKotredes, Kevin Patrick
dc.date.accessioned2020-11-04T16:09:56Z
dc.date.available2020-11-04T16:09:56Z
dc.date.issued2015
dc.identifier.other958157436
dc.identifier.urihttp://hdl.handle.net/20.500.12613/3137
dc.description.abstractThe isocitrate dehydrogenase (IDH) family of enzymes is central to cellular metabolism, catalyzing the oxidative decarboxylation of isocitrate to α-ketoglutarate (α-KG) and production of NADPH. Recently, cancer-associated heterozygous somatic mutations in family members IDH1 and IDH2 were discovered and present predominantly in glioblastoma multiforme and acute myeloid leukemia. The major consequence of these point mutations is the biochemical production of the ‘oncometabolite’ (R)-2-hydroxyglutarate [(R)-2-HG] from α-KG. Recent studies indicate that unalike mutations of IDH2 produce different intracellular levels of (R)-2-HG, suggesting that IDH2 mutations may differentially influence tumorigenesis. Contrasting clinical studies find IDH mutations to be associated either with increased metastatic potential, or higher survival and enhanced chemosensitivity probabilities. Nevertheless, these studies failed to indicate specifically which of the various IDH mutations were found in each of the patients’ tumors. This raises important questions as to whether specific IDH mutations contribute differently to tumorigenesis. In this study, specific IDH2 mutations were evaluated and compared for their chemosensitivity, tumorigenic activity, and production of (R)-2-HG- all notable determinants for their potential use as tumor biomarkers. Three individual clinically relevant IDH2 mutations (IDH2-R172K, -R172M, and -R140Q) or IDH2-WT were expressed in human U87MG glioblastoma cells. We observed distinct changes in cell morphology, proliferation, migration, invasion, anchorage-independent growth and response to chemotherapeutic agents. Differences in base-line activation of various stress pathways were also observed, lending a plausible explanation to the differing phenotypic outcomes. Interestingly, the variable levels of endogenous (R)-2-HG produced by the cell panel inversely correlated with their respective growth rates, implicating (R)-2-HG as a negative regulator of tumor growth. Indeed, treatment of tumor cell lines, expressing IDH2-WT, with exogenous (R)-2-HG induced a decrease in cell proliferation in a dose-dependent manner. When tested in vivo, treatment of tumor-bearing mice with (R)-2-HG significantly reduced tumor volume. These in vivo results complement the results of soft-agar colony forming assays, demonstrating again that (R)-2-HG inhibits tumor growth. In contrast, immortalized cells subjected to long-term (R)-2-HG treatment showed enhanced cell proliferation. Their response to (R)-2-HG, however, could be switched from growth promotion to that of growth inhibition through expression of oncogenic Ras. Thus, these findings demonstrate conclusively that IDH2 mutations are not alike and that oncometabolite (R)-2-HG plays dual roles in tumorigenesis.
dc.format.extent184 pages
dc.language.isoeng
dc.publisherTemple University. Libraries
dc.relation.ispartofTheses and Dissertations
dc.rightsIN COPYRIGHT- This Rights Statement can be used for an Item that is in copyright. Using this statement implies that the organization making this Item available has determined that the Item is in copyright and either is the rights-holder, has obtained permission from the rights-holder(s) to make their Work(s) available, or makes the Item available under an exception or limitation to copyright (including Fair Use) that entitles it to make the Item available.
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/
dc.subjectBiology, Molecular
dc.subjectGenetics
dc.subjectBiochemistry
dc.subject2-hydroxyglutarate
dc.subjectBiomarker
dc.subjectCancer
dc.subjectGlioblastoma
dc.subjectIdh2
dc.subjectMetabolism
dc.titleCharacterization of the effects of IDH2 mutations and (R)-2-HG in cancer progression
dc.typeText
dc.type.genreThesis/Dissertation
dc.contributor.committeememberGallucci, Stefania
dc.contributor.committeememberHoffman, Barbara (Biochemist)
dc.contributor.committeememberRogers, Thomas J., 1950-
dc.contributor.committeememberShore, Scott K.
dc.contributor.committeememberGoldfinger, Lawrence
dc.description.departmentMolecular Biology and Genetics
dc.relation.doihttp://dx.doi.org/10.34944/dspace/3119
dc.ada.noteFor Americans with Disabilities Act (ADA) accommodation, including help with reading this content, please contact scholarshare@temple.edu
dc.description.degreePh.D.
refterms.dateFOA2020-11-04T16:09:56Z


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