Date of Award
11-2023
Degree Type
Thesis
Degree Name
MPhil in Biological and Biomedical Sciences
First Advisor
Dr. Azhar Hussain
Second Advisor
Dr. Amber Palla
Department
Biological and Biomedical Sciences
Abstract
Repurposing of approved non-cancer drugs is a potential source to find new therapeutic options for cancer patients. Digoxin is a non-oncogenic, cardiac glycoside used to treat heart failure and cardiac arrhythmias, it inhibits Na+ -K + ATPase activity, causes accumulation of intracellular Ca++ , and increases cellular oxidative stress, indicating its anti-cancer potential. Hyperthermia (HT) is also an approved widely applicable addendum therapy with the existing cancer treatment modalities. It has been demonstrated that the cell-killing potential of various anti-cancer agents is enhanced in combination with HT. However, to the best of our knowledge, the combined effects of digoxin and HT have not been reported. In this study, we addressed how the digoxin alone or combined with HT induced lethal effects in human monocytic leukemia U937 cells. The effects of drug alone or combined treatment were investigated by employing various methods including cell viability, DNA fragmentation, and Annexin V-FITC/PI apoptosis assay. Giemsa staining was performed to detect morphological changes evident in cell death. Western blot was performed to detect changes in the expression of apoptosis-related proteins. Digoxin treatment alone induced cell death in U937 cells in a concentration-dependent manner, with more significant effects at a dose of 50 and 100 nM. Annexin V-FITC/PI staining also revealed increased apoptosis following digoxin treatment. In addition, caspase-3 expression was also downregulated. Notably, pretreating the cells with an antioxidant N-acetyl-L-cysteine (NAC) fails to protect the digoxin-induced cell death in U937 cells. This result suggests that digoxin-induced cell death is not solely due to the increased intracellular ROS generation. In addition, the combined treatment of digoxin with HT does not show significant synergistic effects on cell viability assay. In contrast, the morphological changes evident in cell death were significantly increased in the combined treatment as compared to either treatment alone. Taken together, the data provides insights into the efficacy and mechanism of digoxin alone, which might help establish digoxin as a repurposed anti-cancer drug. However, its use as a potential sensitizer to HT therapy required further experimental proof.
First Page
1
Last Page
39
Recommended Citation
Rind, Y.
(2023). Investigating drug repurposing: Digoxin-induced cell death alone or combined with hyperthermia in human monocytic leukemia U937 cells.. , 1-39.
Available at:
https://ecommons.aku.edu/etd_pk_mc_mphil-bbs/24