The contribution of autophagy in glioblastoma multiforme cells treated with human recombinant arginase I-induced arginine deprivation. (c2018)

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dc.contributor.author El Jbeily, Elie
dc.date.accessioned 2018-10-17T07:48:59Z
dc.date.available 2018-10-17T07:48:59Z
dc.date.copyright 2018 en_US
dc.date.issued 2018-10-17
dc.date.submitted 2018-07-20
dc.identifier.uri http://hdl.handle.net/10725/8652
dc.description.abstract Glioblastoma multiforme (GBM) is one of the most aggressive and common types of brain cancer. It is associated with a dismal prognosis, thus excluding the possibility of surgical resection. Moreover, it is resistant to traditional chemotherapies and radiotherapies. All this results in a poor survival rate in GBM patients, which doesn’t exceed 1 year. Therefore, there is a need for more selective and effective approaches, such as the use of human recombinant arginase I to selectively target cells that are auxotrophic to arginine. However, the mechanism of cell death due to human recombinant arginase I-induced arginine deprivation is still poorly understood, hence the need for further investigation. In this study, we attempt to investigate the mechanism of cell death following arginine deprivation and in particular the contribution of autophagy. In order to study the effect of apoptosis on GBM cells treated with HuArgI (Co)-PEG5000, Z-VAD, a pan-caspase inhibitor was used. Following the coincubation of SF cells with Z-VAD and HuArgI (Co)-PEG5000, failure of Z-VAD to decrease arginine depletion-induced cell death was shown. Hence demonstrating that apoptosis does not contribute to arginase induced cell death. Furthermore, the contribution of autophagy to arginine depletion-induced cytotoxicity in GBM cells was tested by incubating SF and U87 cells with either HuArgI (Co)-PEG5000 alone and in combination with an autophagy inhibitor (chloroquine or 3- methyladenine) at different time points. Cell death decreased when autophagy was inhibited in SF cells at late time points, thus proving its role in arginine depletion induced cell death. To further study the contribution of autophagy, several autophagy markers were considered. Protein analysis through western blots was conducted to check for the conversion/activation of LC3-I to LC3-II and for the activation of mtTOR to PmTOR. The activation of LC3-I peaked in control conditions (chloroquine treatment), considerably decreased in cells treated with the highest arginase concentration, then increased again in cells treated with both arginase at its highest concentration and chloroquine. mTOR is active in control cells, while at highest arginase concentration there is an inactivation of mTOR resulting in the activation of autophagy. To conclude, we have excluded the contribution of apoptosis in GBM cells. And instead demonstrated the contribution of autophagy to arginase depletion induced cytotoxicity, by checking for autophagy molecular markers, and proving the contribution of such markers by doing cytotoxicity assays and showing the suppression of cell death when autophagy is inhibited. en_US
dc.language.iso en en_US
dc.subject Lebanese American University -- Dissertations en_US
dc.subject Dissertations, Academic en_US
dc.subject Glioblastoma multiforme en_US
dc.subject Apoptosis en_US
dc.subject Cell death en_US
dc.subject Arginine en_US
dc.title The contribution of autophagy in glioblastoma multiforme cells treated with human recombinant arginase I-induced arginine deprivation. (c2018) en_US
dc.type Thesis en_US
dc.term.submitted Summer en_US
dc.author.degree MS in Molecular Biology en_US
dc.author.school SAS en_US
dc.author.idnumber 201003862 en_US
dc.author.commembers Khalaf, Roy
dc.author.commembers Sabbagh, Michella
dc.author.department Natural Sciences en_US
dc.description.embargo N/A en_US
dc.description.physdesc 1 hard copy: xi, 52 leaves; ILL.; 30 cm. available at RNL. en_US
dc.author.advisor Abi-Habib, Ralph
dc.keywords Glioblastoma multiforme en_US
dc.keywords HuArgI (Co)-PEG5000 en_US
dc.keywords Cytotoxicity en_US
dc.keywords Cell death en_US
dc.keywords Autophagy en_US
dc.keywords CQ en_US
dc.keywords 3ma en_US
dc.keywords Z-VAD en_US
dc.keywords LC3-I en_US
dc.keywords LC3-II en_US
dc.keywords mtTOR en_US
dc.keywords P-mTOR en_US
dc.description.bibliographiccitations Bibliography : leaves 33-52. en_US
dc.identifier.doi https://doi.org/10.26756/th.2018.103 en_US
dc.author.email elie.jbeily@lau.edu.lb en_US
dc.identifier.tou http://libraries.lau.edu.lb/research/laur/terms-of-use/thesis.php en_US
dc.publisher.institution Lebanese American University en_US
dc.author.affiliation Lebanese American University en_US

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