A Role for IMPACT in Cancer: Cell survival during tryptophan deprivation

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dc.contributor.advisor Ching, L en
dc.contributor.advisor Tomek, T en
dc.contributor.author Gore, Shanti en
dc.date.accessioned 2018-11-08T02:55:29Z en
dc.date.issued 2018 en
dc.identifier.uri http://hdl.handle.net/2292/44099 en
dc.description Full text is available to authenticated members of The University of Auckland only. en
dc.description.abstract Indoleamine 2,3-dioxygenase (IDO1) mediated immuno-suppression is an active field of cancer research. The IDO1 enzyme catabolises tryptophan to kynurenine, and induces local tryptophan depletion and accumulation of toxic metabolites. Tryptophan depletion in particular, has been shown to cause cell death through activation of the general control non-derepressible 2 (GCN2) pathway in T cells. It is currently unclear why cancer cells persist despite these low nutrient conditions. Research suggests protein expressed from the "IMPrinted and AnCienT gene Protein homolog", IMPACT promotes cancer cell survival during tryptophan depletion. Preliminary studies demonstrated IMPACT was up-regulated in a number of cancers compared to normal tissue. IMPACT over-expression correlated with improved survival of murine glioma cells, suggesting IMPACT may have cell protective effects and maintains amino acid homeostasis of cancer cells during tryptophan depletion, such as that induced by local IDO1 expression. This thesis investigated whether the protein IMPACT plays a role in cancer cell survival during low tryptophan and since IMPACT can inhibit GCN2, whether the GCN2 stress response pathway may be involved. IMPACTmodified GL261 cells had already been developed in the laboratory. To build upon current research by the Stromal Targeting Agents Group, experiments were conducted to characterize IMPACT expression in GL261 IMPACT over expressing, IMPACT wild-type and mutant-IMPACT cell lines via expressing, IMPACT wild-type and mutant-IMPACT cell lines via immunohistochemistry and Western blotting. Live-dead cell assays demonstrated GL261 over-expressing cells grew better than the other lines at low tryptophan, suggesting IMPACT conferred a survival advantage to cells when tryptophan was limited. Western blot analysis of the GCN2 stress response in IMPACT-modified GL261 cells cultured at low tryptophan over 24 hours did not show definitive phosphorylated GCN2 detection. However, phosphorylated eIF2[alpha] increased towards 24 hours in all cells cultured in low tryptophan, at which time ATF4 and CHOP were detected strongly, suggesting a separate stress response had been activated. In conclusion, experiments in this thesis suggested IMPACT may promote survival at low tryptophan conditions in GL261 cells transfected to over-express IMPACT, but pathways other than the GCN2 stress response may be involved in mediating these effects. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof Masters Thesis - University of Auckland en
dc.relation.isreferencedby UoA99265085712602091 en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights Restricted Item. Available to authenticated members of The University of Auckland. en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.rights.uri http://creativecommons.org/licenses/by-nc-sa/3.0/nz/ en
dc.title A Role for IMPACT in Cancer: Cell survival during tryptophan deprivation en
dc.type Thesis en
thesis.degree.discipline Biomedical Science en
thesis.degree.grantor The University of Auckland en
thesis.degree.level Masters en
dc.rights.holder Copyright: The author en
pubs.elements-id 755999 en
pubs.org-id Academic Services en
pubs.org-id Examinations en
pubs.record-created-at-source-date 2018-11-08 en


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