Dual Targeting of Matrix Metalloproteases and the MAPK Pathway in Acute Myeloid Leukemia Cells Using an MMP-activated anthrax lethal toxin (PrAgL1/LF)

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dc.contributor.author Al Saneh, Ahmad
dc.date.accessioned 2022-04-05T11:33:52Z
dc.date.available 2022-04-05T11:33:52Z
dc.date.copyright 2020 en_US
dc.date.issued 2020-05-27
dc.identifier.uri http://hdl.handle.net/10725/13448
dc.description.abstract Anthrax lethal toxin is a two-component toxin consisting of protective antigen (PrAg), the cell binding and translocation domain, and lethal factor (LF), the catalytic domain, which cleaves all mitogen-activated protein/extracellular regulated kinase kinases (MEKs), leading to the inhibition of the MAPK pathway. In order to increase selectivity of this toxin, we have replaced the furin cleavage site with a matrix metalloprotease cleavage site generating an MMP-activated anthrax lethal toxin; PrAgL1/LF. In this study, we attempt to target both the mitogen-activated protein kinase pathway and matrix metalloproteases in acute myeloid leukemia (AML) cell lines. Additionally, we also determine the level of autophagy activation, through quantification of autophagosomes on flow cytometry, and the impact of its inhibition, using the autophagy inhibitor chloroquine (CQ), on cell death secondary to MAPK inhibition. Moreover, we attempt to vertically inhibit the MAPK pathway in AML cell lines in order to overcome acquired resistance of AML cell lines to PrAg/LF by targeting the MAPKK protein MEK-1/2 as well as the MAPKKK protein ERK-1/2 via SCH772984, showing that coupling the two inhibitors may offer a novel targeting method in order to overcome acquired resistance to MEK-1/2 inhibitors. Our results demonstrate that vertical inhibition does offer increased potency in comparison to single targeting of the MAPK pathway when working with sensitive cell lines that are dependent on the cascade. Several cell lines tested were sensitive to PrAgL1/LF indicating that they express MMPs and are sensitive to the inhibition of the MAPK pathway. The expression of MMPs by AML cell lines was further confirmed by their sensitivity to PrAgL1/FP59, an MMP activated version of anthrax toxin whose cytotoxicity is not related to their dependence on the MAPK pathway. Inhibition of the MAPK pathway through PrAgL1/LF led to sustained activation of autophagy, starting at 24 hours and lasting up to 120 hours following treatment with PrAgL1/LF in the AML cell lines. Addition of CQ led to an increase in cell cytotoxicity following treatment with PrAgL1/LF, at all time points, indicating that the inhibition of the MAPK pathway in AML cells leads to the activation of autophagy, which in turn mediates cell death following treatment with PrAgL1/LF. Our study shows that AML cells express MMPs and can be targeted using an MMP-activated anthrax lethal toxin and that the LF-mediated inhibition of the MAPK pathway activates autophagy which is protective at later time points. en_US
dc.language.iso en en_US
dc.subject Dissertations, Academic en_US
dc.subject Cancer -- Molecular aspects en_US
dc.subject Blood -- Diseases -- Molecular aspects en_US
dc.subject Mitogen-activated protein kinases en_US
dc.subject Lebanese American University -- Dissertations en_US
dc.subject Acute myeloid leukemia -- Pathogensis en_US
dc.title Dual Targeting of Matrix Metalloproteases and the MAPK Pathway in Acute Myeloid Leukemia Cells Using an MMP-activated anthrax lethal toxin (PrAgL1/LF) en_US
dc.type Thesis en_US
dc.term.submitted Spring en_US
dc.author.degree MS in Molecular Biology en_US
dc.author.school SAS en_US
dc.author.idnumber 201402738 en_US
dc.author.commembers Dan, Georgess
dc.author.commembers Sabbagh, Michella Ghassibe
dc.author.department Natural Sciences en_US
dc.description.physdesc 1 online resource (ix, 56 leaves) ill. (some col.) en_US
dc.author.advisor Abi Habib, Ralph
dc.keywords Anthrax Lethal Toxin en_US
dc.keywords Autophagy en_US
dc.keywords PrAg/LF en_US
dc.keywords ERK inhibitor en_US
dc.keywords Acute Myeloid Leukemia en_US
dc.keywords Mitogen Activated Protein Kinase Pathway (MAPK) en_US
dc.description.bibliographiccitations Bibliography: leaf 49-56. en_US
dc.identifier.doi https://doi.org/10.26756/th.2022.333
dc.author.email ahmad.alsaneh@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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