Author ORCID Identifier
https://orcid.org/0009-0000-8384-5268
Date Available
8-13-2025
Year of Publication
2025
Document Type
Doctoral Dissertation
Degree Name
Doctor of Philosophy (PhD)
College
Medicine
Department/School/Program
Pharmacology and Nutritional Sciences
Faculty
Dr. Jessica Blackburn
Abstract
Relapsed T-cell Acute Lymphoblastic Leukemia (T-ALL) patients have dismal prognosis, with 5-year overall survival rates of 10% for adults and 36% for children. Relapse is attributed to the inability of chemotherapy agents to eliminate Leukemia Stem Cells (LSCs) that can repopulate the leukemia. Those cells exist with a unique genetic, transcriptomic, and metabolic profile compared to the rest of the leukemia and thus, finding targeted therapies toward this population of cells can result in disease eradication and elimination of relapse. However, investigating LSCs is challenging-particularly in T-ALL- for two reasons: 1) the lack of robust surface markers that define LSCs and 2) those cells exist at very low frequency in T-ALL mouse models and patient samples.
A transgenic model of rag2-myc–derived T-ALL in zebrafish offers solutions to these challenges. Leukemia clones derived from this model have LSC frequency of ~10%, compared to < 0.01% in mouse models, generating an excellent environment to interrogate T-ALL LSC biology and identify specific targets.
Across my thesis projects, I capitalized on zebrafish as an animal model and on FDA-approved compounds- to facilitate clinical translation to identify novel inhibitors of self-renewal in T-ALL. Through an in vivo, target-based drug screening, we identified Erlotinib as an inhibitor of Wnt/β-catenin signaling and a blocker of self-renewal in T-ALL. A subsequent phenotypic drug screening using >2,500 CG1 zebrafish identified Amiloride as an inhibitor of T-ALL LSC in vivo and in vitro. Amiloride is also an inhibitor of the Sodium Hydrogen Exchanger-1 (NHE1). Importantly, NHE1 has not been previously linked to self-renewal in hematologic malignancies, presenting a novel therapeutic strategy to inhibit LSCs.
Inhibition of NHE1 through pharmacological treatment or KD studies resulted in impaired mitochondrial function and morphology. This was evident through the multi-omics profiling of KD cells. Transcriptomics and proteomics analysis identified downregulation in oxidative phosphorylation and mitochondrial biosynthesis pathways, while untargeted metabolomics revealed global metabolic reprogramming. These findings underscore the critical contribution of mitochondria to LSC biology and function.
In summary, my thesis leveraged a zebrafish T-ALL model with high LSC frequency to uncover novel regulators of self-renewal. I have integrated in vivo modeling, drug repurposing, multi-omics approaches to identify LSC specific vulnerabilities with the over-all goal of achieving durable remission for T-ALL patients.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2025.439
Recommended Citation
Al-Hamaly, Majd, "Zebrafish Models to Uncover Targetable Mechanisms of Self-Renewal In T-Cell Acute Lymphoblastic Leukemia" (2025). Theses and Dissertations--Pharmacology and Nutritional Sciences. 65.
https://uknowledge.uky.edu/pharmacol_etds/65
