- Title
- Design and synthesis of arylhydrocarbon receptor ligands for the treatment of breast cancer
- Creator
- Baker, Jennifer R.
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2020
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Breast cancer, despite the massive amount of public awareness and private and public funding associated with its research, is still the most common cancer in women worldwide. Stage IV sufferers, also referred to as metastatic breast cancer, face a dismal 5 year survival rate, and there remains no effective targeted treatment for triple-negative phenotypes. Despite increasing survival rates, annually over 600,000 women succumb to this insidious disease globally. The current first-line chemotherapeutics are non-selective, and thus carry dreadful side-effects. With effective directed treatments desperately needed, new biological targets are sought. The Arylhydrocarbon Receptor (AhR), well-known for its role in the metabolism of xenobiotic ligands, has emerged in the last decade as a promising target. Two AhR ligands have advanced to clinical trials; with one, Aminoflavone, progressing as far as Phase II before ultimately aborting due to lung toxicity. This thesis reports on research conducted into the application of AhR ligands to breast cancer in vitro, in the attempt to solve this problem. A comprehensive review of the AhR, and its role in the possible future treatment of breast cancer, was compiled: bringing together the work conducted in this area in recent years. Included in this compilation is the discussion of the application of present drugs to this disease via the AhR as a novel target, as well as discussion of new ligands that have been identified (Chapter 2). Two broad structures libraries were investigated in the synthetic aspect of this work, with a significant amount of structure-activity relationship study conducted on the acrylonitrile scaffold. In addition, a selection of naphthalamide-based ligands were prepared and tested, with some excellent results reported. The results of these investigations demonstrate the extremely promising nature of the AhR for future breast cancer treatments, with a number of nano-molar potent ligands afforded. Beginning with the generation of a homology model to allow the virtual design of AhR ligands (Chapter 3), our efforts uncovered (Z)-N-(4-(2-cyano-2-(3,4-dichlorophenyl)vinyl)phenyl)acetamide (1), which exhibited a 34 nM GI50 in the estrogen-receptor positive MCF-7 breast cancer cell line, and demonstrating over 400-fold selectivity over the healthy breast cell line MCF10A (Chapter 4). In efforts to increase the solubility of these ligands, improvements to their fsp3 character was investigated. To this end, a robust flow protocol was developed to enable the rapid generation of a range of β-amino alcohol functionalised acrylonitriles (Chapter 5). Applying this protocol to the desired substrates allowed the synthesis of a comprehensive range of analogues (Chapter 6). An anomaly in the standard MTT assay was observed, with a metabolite forming in vitro that was interfering with the observed results. Whilst it is well-reported that analogues can interfere in the MTT assay, with results demonstrating that the ligands are less biologically active, the opposite is very under-reported: the prepared analogues gave results that demonstrated that they were more biologically active than the morphological assessment demonstrated. Therefore, an SRB assay was used for these ligands, to determine their cytotoxicity (Chapter 7). Exploration of the naphthalimide scaffold, beginning with the known AhR ligand 10-Cl-BBQ (2), a range of modifications were conducted to both simplify the structure to improve synthetic accessibility, and improve the solubility of the analogues. Our studies uncovered the 2-amino functionalised analogue NAP-6 (3), which expressed a 70 nM GI50 in the estrogen-receptor positive MCF-7 breast cancer cell line, and exhibited over 40-fold selectivity over the healthy breast cell line MCF10A (Chapter 8). This work serves to demonstrate that the AhR is a very promising target for future breast cancer treatments, with the targeting of the AhR pathway leading to a number of analogues that demonstrated excellent activity and selectivity over a number of oncogenic cell lines. This study not only adds significantly to the knowledge gap in this area by producing a comprehensive review on the role of the AhR as a breast cancer drug target and a number of extremely potent and selective AhR ligands, but also indicates the precautionary nature some initial biological results should be approached with.
- Subject
- arylhydrocarbon receptor; breast cancer; molecular modelling; flow chemistry; medicinal chemistry
- Identifier
- http://hdl.handle.net/1959.13/1414045
- Identifier
- uon:36694
- Rights
- Copyright 2020 Jennifer R. Baker
- Language
- eng
- Full Text
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| View Details Download | ATTACHMENT01 | Thesis | 38 MB | Adobe Acrobat PDF | View Details Download | ||
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