Development of boronic acid modified topoisomerase I inhibitors as covalent-binding chemotherapeutic agents

Simple item page
dc.contributor.authorVuong, Billy
dc.contributor.examiningcommitteeBurczynski, Frank (Pharmacy)
dc.contributor.examiningcommitteeKatyal, Sachin (Pharmacology and Therapeutics)
dc.contributor.examiningcommitteeKrol, Ed (University of Saskatchewan)
dc.contributor.supervisorTranmer, Geoffrey
dc.contributor.supervisorHasinoff, Brian
dc.date.accessioned2024-08-19T19:29:49Z
dc.date.available2024-08-19T19:29:49Z
dc.date.issued2024-08-12
dc.date.submitted2024-08-13T02:40:46Zen_US
dc.degree.disciplinePharmacy
dc.degree.levelDoctor of Philosophy (Ph.D.)
dc.description.abstractIntroduction: Camptothecins are effective chemotherapeutic agents due to their ability to inhibit topoisomerase 1 (Top1), an enzyme that changes the topology of DNA through relaxation of DNA supercoils for cellular processes such as DNA replication. Through inhibition of Top1, programmed cell death can be induced in cancer cells undergoing rapid proliferation. Covalent inhibitors are a class of drug that offer stronger receptor interactions, improved potency, selectivity, and duration of action over non-covalent drugs. We hypothesize that we can develop drug candidates using a functional boron warhead that forms an additional targeted covalent interaction with the Top1 cleavage complex, generating optimized chemotherapeutic agents for pre-clinical study. Methods: Drug candidates were synthesized, purified by flash chromatography, and characterized by NMR and mass spectroscopy. The drug candidates underwent in vitro evaluation of cancer anti-proliferative capability and covalent mechanism of action. Cell viability (MTT/MTS) assays were performed against several cell lines after 72 h of drug exposure. Annexin-V flow cytometry was used to assess apoptotic capability of drug candidates. Covalent binding experiments were performed using washout assays and modified agarose gel-based cleavage/relaxation assays on Top1 nuclear extract and pBR322 DNA. Results: The drug candidates displayed potent cancer growth inhibition activity with nanomolar half maximal inhibitory concentrations (IC50s) against several cancer cell lines. Several drug candidates were submitted to the National Cancer Institute 60 human tumor cell lines screen where they showed potent anti-proliferative activity (<10 nM GI50) against central nervous system type cancers. Annexin-V flow cytometry assay revealed drug candidates induce similar apoptosis and cell death scatter profiles to clinically approved Top1 inhibitors. Washout and salt reversal assays suggest potential of one of the drug candidates to resist washout and salt induced reversal of ternary complex through formation of a covalent complex with Top1. Conclusion: The drug candidates displayed potent cancer growth inhibition activity through the formation of a ternary complex with Top1 and DNA. Washout and salt reversal assays suggest one of our candidates forms an additional covalent interaction with the Top1 through stabilization of the ternary cleavage complex.
dc.description.noteOctober 2024
dc.identifier.urihttp://hdl.handle.net/1993/38396
dc.language.isoeng
dc.rightsopen accessen_US
dc.subjectBoron
dc.subjectMedicinal Chemistry
dc.subjectTopoisomerase
dc.subjectCovalent Binding
dc.subjectChemotherapy
dc.subjectCancer
dc.subjectCamptothecin
dc.titleDevelopment of boronic acid modified topoisomerase I inhibitors as covalent-binding chemotherapeutic agents
dc.typedoctoral thesisen_US
local.subject.manitobano
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Billy Vuong - PhD Thesis_Final Version.pdf
Size:
18.66 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
770 B
Format:
Item-specific license agreed to upon submission
Description:
Download
Collections
FGS - Electronic Theses and Practica