Date Available

7-6-2024

Year of Publication

2024

Document Type

Doctoral Dissertation

Degree Name

Doctor of Philosophy (PhD)

College

Pharmacy

Department/School/Program

Pharmaceutical Sciences

Advisor

Dr. Jill Kolesar

Abstract

Lung cancer is the global leading cause of cancer related death. Non-small cell lung cancer (NSCLC) accounts for 80% of lung cancer diagnoses conferring a significant disease burden. However, certain mutations in tumor suppressors such as Kelch-like ECH-associated protein 1 (KEAP1) confers resistance to standard of care therapy in NSCLC. KEAP1 is known to regulate multiple cellular processes such as oxidative stress response and anti-apoptotic pathways. Furthermore, KEAP1 loss of function in NSCLC is associated with poorer clinical outcomes and there are no currently approved therapies for KEAP1 loss NSCLC and represents an unmet clinical need. Artesunate (Art) demonstrated anti-cancer activity in established non-small cell lung cancer NSCLC cell lines. In NSCLC cell lines, loss of KEAP1 function has also been demonstrated to confer resistance to Art in vitro. However, Art resistance in KEAP1 loss NSCLC cell line was overcome by direct inhibition of NRF2. However, at the time of study, the direct NRF2 inhibitor was yet to be in clinical development. Therefore, compounds with current approved indication or in clinical development phases were screened against Art for further preclinical development in KEAP1 mutated NSCLC. Three compounds (Navitoclax, cisplatin, and CB839) were identified as having statistically significant synergy scores when combined with Art in KEAP1 loss NSCLC cell line. Navitoclax (Nvt), an anti BCL-2 family inhibitor, was selected for further preclinical evaluation with Art. Our study demonstrated that in vitro Art activity was decreased in KEAP1 loss NSCLC by Nvt at a therapeutic concentration. Knockdown of KEAP1 also demonstrated that Art and Nvt pharmacological activity was maintained. In mice experiments, in vivo Art-Nvt combination was driven by Nvt likely due to unachievable therapeutic concentrations of Art in mice. To further evaluate mechanism, apoptosis analysis demonstrated that there was an increase in apoptosis in Art-Nvt combination but was not significantly different compared to Nvt alone, which supports that Nvt was a driver of apoptosis in the in vivo model. Future studies will include further evaluation of Art pharmacokinetics in mice models, assessment of mechanism of pharmacological activity between Art and Nvt, and identification of other Art-drug combinations.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2024.362

Funding Information

This study was supported by American College of Clinical Pharmacy Foundation Futures Student grant from 2022 to 2023. This study was supported by American Foundation for Pharmaceutical Education Pharmaceutical Science Pre-Doctoral fellowship from 2023-2024.

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