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Characterisation of Small Ubiquitin-like Modifier (SUMO) protein complex expression in human cancer cells to identify novel therapeutic targets

Salih, Mohammed A.M.
Publication Date
End of Embargo
Supervisor
Kantamneni, Sriharsha
Williamson, Ritchie
Keywords
SUMOylation, Naked-mole rat, Breast cancer, Colorectal cancer, Neuroblastoma, qRT-PCR, Western Blot, Colony formation, Invasion and migration assay, Small Ubiquitin-like Modifier (SUMO), SUMO complex expression
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Creative Commons License
The University of Bradford theses are licenced under a Creative Commons Licence.
Peer-Reviewed
Open Access status
Accepted for publication
Institution
University of Bradford
Department
Institute of Cancer Therapeutics. School of Pharmacy and Medical Sciences. Faculty of Life Sciences
Awarded
2023
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PhD Thesis
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Additional title
SUMO complex expression in cancer cells
Abstract
SUMOylation is a post-translational modification where a number of small ubiquitin-like modifier proteins (SUMO) are conjugated to lysine residues of the target proteins and contribute to various cellular functions essential for cancer cell survival and proliferation. The unique behaviours, phenotypic and molecular adaptations found in the naked-mole rat (NMR) suggest a high stability and effective functioning of the molecular machinery that counteracts damage accumulation in its genome. NMR can reach 32 years, shows no signs of ageing, and possesses a very efficient mechanism of resistance to cancer. This study aims to investigate the regulation of SUMOylation machinery between NMR tissues in comparison to human cancer cells, to find novel targets for cancer therapy. Gene expression of SUMO isoforms between NMR and humans, were investigated through qRT-PCR. The data suggests a significant low expression level for most SUMO machinery (except PIAS4) in NMR brain and intestine tissues compared to MCF-7, DLD-1, SH-SY5Y, and MCF-10A cells. Western blotting analysis also revealed high protein expression of PIAS4 in NMR compared to SENP1 and Ubc9. SUMO machinery expression levels from NMR are recapitulated in cancer cells either by silencing (hUBE2I: shRNA, hSENP1: shRNA) or overexpression (Myc/hPIAS4: Exp) to study functional effects. Cytotoxicity assays were analysed in relevance to Doxorubicin in MCF-7, 5-Fluorouracil in DLD-1 and Methotrexate in SH-SY5. Additionally, functional clonogenic and invasion assays were performed including apoptotic mechanisms (Bcl-2, and BID). In conclusion, the data revealed important differences in SUMOylation machinery between NMR and human cancer cells, which provides a future therapeutic path for cancer treatment.
URI
https://bradscholars.brad.ac.uk/handle/10454/20583
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Type
Thesis
Qualification name
PhD
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