- Title
- Assessing the efficacy of bispidinones as novel pancreatic cancer therapeutic agents
- Creator
- McCluskey, Siobhann N.
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2022
- Description
- Masters Research - Master of Philosophy (MPhil)
- Description
- Pancreatic cancer is a devastating disease with an abysmal <10% survival rate at 5-years. With over 48,000 projected deaths in the USA for 2021, it is now the third most common cause of cancer death and is poised to number two by 2030. Current therapies, with only ~6-month life extension should be considered palliative at best and highlight the need for novel therapeutic agents targeting molecular subtypes not responsive to current treatments. The highly heterogenic and metastatic nature of PC presents a major challenge in therapeutic development. There has been no real enhancement in PC patient outcomes in the past 5-decades. Current therapeutic approaches have yet to provide any significant improvement to the overall survival of patients, and as such, there is an urgent need for the discovery and development of novel treatments. There is always a need to discover new drug treatments for cancers, and historically natural products have been utilised as a source for treatments for a wide range of diseases. Drugs derived from natural sources provide a wide range of chemical, structural and biological diversity, which make them a valuable source for the development of new anti-cancer drugs. While natural products have been, and currently are used, as a valuable source of new anti-cancer agents, there are key limiting factors that occur with them. Some of these factors include that they often have limited solubility and can show considerably cytotoxicity and off-target effects, which results in a narrowing of therapeutic indices. While these limitations are somewhat prohibitive, the large amount of structural and stereochemistry diversity offered by naturally derived products means that the skeletons of these can serve as templates for the exploration of novel targets, and the chemical synthesis of anti-cancer agents with greater biological relevance. Since their initial discovery, the synthesis and stereochemistry of bispidinones have sparked significant interest with regard to their biological activity and privileged scaffold. Bispidinones have a unique skeleton, with a bicyclic ring structure that forms a rigid, versatile structure, which has appeared many times across many different biological targets. As a consequence of the versatility of the bispidinone scaffold, and the recent evidence of anti-pancreatic cancer activity by Predebon et al (2019), it was hypothesised that bispidinone analogues will show an anti-cancer effect against pancreatic cancer cells in vitro. To investigate this hypothesis, the following aims were addressed. 1. To synthesise and characterise new bispidinone analogues.; 2. Assess the growth inhibitory capacity of the novel bispidinone analogues against pancreatic cancer cell lines in vitro.; 3. Engage in the cyclical process of developing a structure activity relationship and further analogues in an attempt to increase potency against the cell lines targeted. A series of 70 different bispidinone analogues were synthesised using peptide coupling reactions and gave mixed results: with some of the analogues unable to be synthesised and fully characterised. Optimisation of the reaction conditions allowed the successful peptide coupling of the N,N’-unsubstituted bispidinone with various acid additions to proceed, generating an array of novel bispidinone analogues. This study then investigated the cytotoxicity of the two synthesised libraries consisting of 70 different bispidinone analogues, against 3 different PC cell lines (Mia PaCa-2, BxPC3 and ASPC-1). Cytotoxicity of 42 bispidinone analogues (25-66) were assessed via an initial first-pass screen at the concentration of 25 μM against three different pancreatic cancer cell lines (MiaPaca-2, BxPC-3 and ASPC-1). Cytotoxicity was determined by measuring the live cell growth activity via the MTT assay. Six analogues (28, 39, 53, 63, 65 and 66) were selected for further screening, due to their elicitation of low cell growth in one or more cell line. These compounds were then screened via a dose response analysis, in which the compounds were screened at 8 different concentrations ranging from 50-0.0001 μM, to determine their IC50 values against the three pancreatic cancer cell lines. IC50 values for these 6 bispidinone analogues ranged from 3.3 – 17.3 μM in Mia PaCa-2 cells; 13 – 32 μM in BxPC3 cells; and 15 – 34.6 μM in ASPC-1 cells. The data generated from Aims 1 and 2 (eg. substitution patterns of the newly-added aromatic rings; and cytotoxicity) are important as it enabled an informed inference of which additions may confer a greater effect on the cancer cell lines, and were thus utilised to create additional, modified libraries for further characterization and assessment. As such, additional substitution reactions (eg. electron withdrawing additions such as chlorine, as well as cinnamic, hydroxyl-substituted, and hydroxy acids) were performed to generate 28 new bispidinone analogues, which were to be assessed for their cytotoxic activity against the pancreatic cancer cells (analysis of cytotoxicity data yet to be finalised due to Covid-19 lockdown of the Medical Oncology Laboratory). In conclusion, this study revealed that of the 38 bispidinone analogues synthesised and screened, six exhibited a cytotoxic effect on Mia PaCa-2, BxPC3 and ASPC-1 cell lines, in a dose-dependent manner. Further, that bispidinones which contained longer carbon chains, as well as analogues that contain election withdrawing substitutions, are of more interest in an anti-pancreatic cancer context. This study builds on previous work conducted in our laboratories on the anti-pancreatic cancer effects of bispidinone analogues. Importantly, these data add to the growing number of studies being undertaken globally to tackle this aggressive and devastating disease, in the hope that they can be used to provided better outcomes for pancreatic cancer patients.
- Subject
- pancreatic cancer; bispidinones; molecular subtypes; bispidinone analogues
- Identifier
- http://hdl.handle.net/1959.13/1508282
- Identifier
- uon:56114
- Rights
- Copyright 2022 Siobhann N. McCluskey
- Language
- eng
- Full Text
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