E-Thesis 382 views 563 downloads
Targeting Ferroptosis in Tuberous Sclerosis Cell Line Models / TASMIA TAHSIN
Swansea University Author: TASMIA TAHSIN
DOI (Published version): 10.23889/SUthesis.69835
Abstract
Ferroptosis, an iron-dependent cell death mechanism characterized by oxidative damage to phospholipids and subsequent membrane damage, presents a promising target for cancer therapy. The TSC1-TSC2 complex is crucial in cellular signalling, regulating cell growth, proliferation, and metabolism. Mutat...
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Swansea, Wales, UK
2025
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| Institution: | Swansea University |
| Degree level: | Doctoral |
| Degree name: | Ph.D |
| Supervisor: | Conlan, Steve ; Gonzalez, Deya ; Davies, Mark ; Tee, Andrew ; Hughes, Stephen Fôn |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa69835 |
| Abstract: |
Ferroptosis, an iron-dependent cell death mechanism characterized by oxidative damage to phospholipids and subsequent membrane damage, presents a promising target for cancer therapy. The TSC1-TSC2 complex is crucial in cellular signalling, regulating cell growth, proliferation, and metabolism. Mutations or loss of TSC2 lead to hyperactivation of mTORC1, implicated in various cancers. This research aimed to elucidate the role of TSC2 loss in ferroptosis and its contribution to drug resistance in TSC2-cell line models, potentially guiding the development of new therapeutic strategies. Cytotoxicity testing within this study revealed that Tsc2-deficient cells have greater resistance to ferroptosis induction compared to Tsc2-positive cells. Notably, inhibition of mTORC1 did not reverse this resistance, whereas NRF2 antioxidant pathway inhibition and AMPK activation did, suggesting that resistance operates through mTORC1-independent pathways. Biochemical analysis identified altered ferroptosis markers in Tsc2-deficient cells, such as ROS-mediated lipid peroxidation, GPX4, GSH, and labile iron pools as key factors in this resistance. Further investigations into NRF2 revealed significantly elevated nuclear translocation upon ferroptosis induction in Tsc2-deficient cells during ferroptosis induction, identifying the NRF2 pathway as a potential mediator of resistance. qPCR and RNAseq analyses confirmed significant dysregulation of NRF2 and its target genes between TSC2-deficient and TSC2-expressing tumours. Additionally, inhibition of ferroptosis suppressor protein 1 (FSP1) also counteracted the cell death resistance in Tsc2-deficient cells. These cells displayed a fourfold increase in mRNA levels of FSP1, which significantly enhanced their resistance to ferroptosis. Overall, this thesis establishes that the loss of TSC2 confers resistance to ferroptosis through mechanisms that are independent of mTORC1 overactivation but dependent on NRF2 activation. This study also provides a deeper understanding of ferroptosis and additional cellular signalling pathways, such as those involving ROS regulation, lipid peroxidation, and iron metabolism, within the context of TSC2 loss. These insights will guide the development of future therapeutic strategies targeting ferroptosis in TSC2-deficient cancers. |
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| Keywords: |
Cell biology, Cancer, Cell signalling, Biochemistry |
| College: |
Faculty of Medicine, Health and Life Sciences |
| Funders: |
KESS 2 Knowledge Economy Skills Scholarships |