Thesis
Integrating experimental and omics approaches for investigation of novel combination therapies to overcome therapeutic resistance in triple-negative breast cancer.
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2025
- Thesis identifier
- T17506
- Person Identifier (Local)
- 202187784
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer characterised by negative expression of typical receptors including oestrogen (ER), progesterone (PR), and human epidermal growth factor receptor 2 (HER2). The current therapeutic strategies of TNBC primarily rely on chemotherapeutics, such as Anthracyclines, Taxanes, and Platinum-based agents, as well as radiotherapy for regionally located tumours. However, therapy resistance and tumour reoccurrence remain the major challenges, highlighting that the development of novel targeted and combination therapy is urgently needed. This project aimed to investigate targeted therapeutic approaches for TNBC by assessing the effectiveness of gedatolisib, a dual PI3K/mTOR inhibitor, combined with conventional treatments such as doxorubicin and radiotherapy. A radioresistant TNBC cell line was established in our lab alongside its parental counterpart to further investigate the potential of these gedatolisib-based combination therapies in overcoming therapy resistance. A metabolomics approach was also employed to investigate the metabolic adaptations associated with radioresistance in TNBC, aiming to identify key resistance pathways and potential therapeutic targets. The therapeutic efficacy of single and combination treatments in both parent and radioresistant MDA-MB-231 cell lines was assessed utilising two-dimensional clonogenic assays and three-dimensional tumour spheroids. To determine the mode of action of any promising combinations, mechanistic assays, including Annexin V (for apoptosis), COMET assay (for DNA damage), cell cycle analysis, and autophagy assay, were conducted to provide molecular insights into the mechanisms of therapyinduced cytotoxicity. Furthermore, the liquid chromatography-mass spectrometry (LC/MS) technique was employed to identify the metabolites and their intensities altered in the parent and radioresistant MDA-MB-231 cells to determine the pathways potentially utilised in inducing radioresistance. The data demonstrated that combining gedatolisib with gold standard treatments such as radiation or doxorubicin was effective in the wild-type and resistant MDA-MB-231 cell lines. In both cell lines, cell survival and tumour spheroid growth were significantly reduced following treatment with combination therapy compared to monotherapy (P<0.05). These results were further supported by mechanistic assays, which demonstrated increased apoptosis induction, enhanced DNA damage, and altered cell cycle patterns in response to a combination of 0.1μM gedatolisib with either 2 Gy radiation or 0.01μM doxorubicin. The metabolomics data analysis identified alterations in crucial metabolic pathways, including arginine biosynthesis, alanine-aspartate-glutamate metabolism, and the TCA cycle. Although these metabolic pathways are vital for cancer cells, their dysregulation may contribute to inducing radioresistance in MDA-MB-231 cells. The collective results propose that targeting metabolic reprogramming alongside inhibiting the PI3K/Akt/mTOR pathway may offer a novel therapeutic approach for overcoming radioresistance in TNBC. Overall, the current project highlights the potential of gedatolisib in combination therapy to improve treatment outcomes in TNBC patients and identifies metabolic pathways that may serve as future therapeutic targets.
- Advisor / supervisor
- Mullen, Alexander
- Boyd, Marie
- Resource Type
- DOI
Relations
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PDF of thesis T17506 | 2025-11-13 | Public | Download |