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dc.contributor.advisorWondrak, Georg T.en_US
dc.contributor.authorQiao, Shuxi
dc.creatorQiao, Shuxien_US
dc.date.accessioned2014-01-14T21:27:07Z
dc.date.available2014-01-14T21:27:07Z
dc.date.issued2013
dc.identifier.urihttp://hdl.handle.net/10150/311348
dc.description.abstractCumulative evidence suggests that constitutively elevated levels of proteotoxic stress represent a specific vulnerability of malignant cells that can be targeted by pharmacological modulation of the intracellular proteotoxic stress response. According to this emerging mechanism, small molecule stress modulators may induce deviations from protein homeostasis causing cytotoxicity confined to malignant cells already at a high set point of constitutive proteotoxic stress leading to functional impairment and even cell death. In contrast, normal cells with sufficient protein degradation capacity can tolerate the extra dysfunctional protein overload. My graduate research has focused on testing the feasibility of repurposing clinically used non-oncological drugs for experimental chemotherapy targeting metastatic melanoma cells. The following specific aims were pursued: (1) To identify clinically used non-oncological drugs that preferentially induce cytotoxicity in melanoma cells but not primary melanocytes through upregulation of proteotoxic and/or oxidative stress; (2) To explore the specific molecular mechanisms underlying induction of melanoma cell apoptosis by lead compounds focusing on oxidative and proteotoxic stress modulation; (3) To explore efficacy of selected lead compounds for antimelanoma intervention in a murine xenograft model. First, we demonstrate feasibility of using the FDA-approved redox-active D-cysteine-derivative D- penicillamine for chemotherapeutic intervention targeting human A375 melanoma cells in vitro and in vivo through induction of the unfolded protein response (UPR). Second, we demonstrate that the antimicrobial oligopeptide thiostrepton displays dual activity as a selective prooxidant and proteasome inhibitor causing proteotoxic stress that preferentially targets malignant melanoma and multiple myeloma cells. Third, we demonstrate for the first time that the clinically used 4-aminoquinoline antimalarial amodiaquine causes autophagic-lysosomal and proliferative blockade sensitizing human melanoma cells to starvation- and chemotherapy-induced melanoma cell death. Taken together, our data indicate the chemotherapeutic potential of small molecule proteotoxic stress inducers and strongly suggest feasibility of repurposing specific non-oncological drugs for proteotoxic stress-directed antimelanoma intervention.
dc.language.isoen_USen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectPharmacology & Toxicologyen_US
dc.titlePharmacological Modulation of Oxidative and Proteotoxic Stress for Antimelanoma Interventionen_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.contributor.committeememberWondrak, Georg T.en_US
dc.contributor.committeememberCherrington, Nathanen_US
dc.contributor.committeememberKlimecki, Walten_US
dc.contributor.committeememberChen, Qin M.en_US
dc.contributor.committeememberBriehl, Margareten_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplinePharmacology & Toxicologyen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-05-28T00:41:13Z
html.description.abstractCumulative evidence suggests that constitutively elevated levels of proteotoxic stress represent a specific vulnerability of malignant cells that can be targeted by pharmacological modulation of the intracellular proteotoxic stress response. According to this emerging mechanism, small molecule stress modulators may induce deviations from protein homeostasis causing cytotoxicity confined to malignant cells already at a high set point of constitutive proteotoxic stress leading to functional impairment and even cell death. In contrast, normal cells with sufficient protein degradation capacity can tolerate the extra dysfunctional protein overload. My graduate research has focused on testing the feasibility of repurposing clinically used non-oncological drugs for experimental chemotherapy targeting metastatic melanoma cells. The following specific aims were pursued: (1) To identify clinically used non-oncological drugs that preferentially induce cytotoxicity in melanoma cells but not primary melanocytes through upregulation of proteotoxic and/or oxidative stress; (2) To explore the specific molecular mechanisms underlying induction of melanoma cell apoptosis by lead compounds focusing on oxidative and proteotoxic stress modulation; (3) To explore efficacy of selected lead compounds for antimelanoma intervention in a murine xenograft model. First, we demonstrate feasibility of using the FDA-approved redox-active D-cysteine-derivative D- penicillamine for chemotherapeutic intervention targeting human A375 melanoma cells in vitro and in vivo through induction of the unfolded protein response (UPR). Second, we demonstrate that the antimicrobial oligopeptide thiostrepton displays dual activity as a selective prooxidant and proteasome inhibitor causing proteotoxic stress that preferentially targets malignant melanoma and multiple myeloma cells. Third, we demonstrate for the first time that the clinically used 4-aminoquinoline antimalarial amodiaquine causes autophagic-lysosomal and proliferative blockade sensitizing human melanoma cells to starvation- and chemotherapy-induced melanoma cell death. Taken together, our data indicate the chemotherapeutic potential of small molecule proteotoxic stress inducers and strongly suggest feasibility of repurposing specific non-oncological drugs for proteotoxic stress-directed antimelanoma intervention.


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