Looi-Somoye, Remi;
(2022)
Degradation of onco-proteins and oncogenic mediator proteins as a novel approach to treat acute leukaemia.
Doctoral thesis (Ph.D), UCL (University College London).
Preview |
Text
RLS PhD Thesis - UCL.pdf - Accepted Version Download (9MB) | Preview |
Abstract
The aim of this study was to evaluate the effect of degrading MLL-fusion oncoproteins with niclosamide, and to develop a degradation-based drug screening assay that targets two mediators of acute myeloid leukaemia, METTL3 and UHRF1. Our lab has previously shown that inhibition of MLL-fusions resulted in disease remission for MLL-rearranged leukaemia. A degradation drug screen against the MLL-fusion MLL-AF9 identified niclosamide as a positive hit compound. Validation of this compound in MLL-rearranged acute lymphoid leukaemia showed that niclosamide caused loss of MLL-fusion proteins in cell lines and primary patient samples. This resulted in the downregulation of MLL-fusion target genes HOXA7 and HOXA10. Furthermore, niclosamide increased apoptosis and inhibited self-renewal capacity, whilst having minimal effect on normal hematopoietic stem progenitor cells. For the second part of this project, a dual-luciferase drug screening platform was established by creating indicator cell lines co-expressing renilla luciferase and METTL3 or UHRF1 fused to firefly-luciferase in THP1 cells. Both models were screened against 1,280 clinically approved drugs for a repurposing screen. Additionally, the METTL3 model was also screened against 1,200 compounds from a diverse kinase inhibitor library. In total, 16 compounds passed the initial screen by lowering dual-luciferase ratio, and 4 passed the cross-validation step by reducing protein expression in western blot. 2 compounds that targeted METTL3 were validated and characterised further in AML cell lines. The compounds induced efficient loss of METTL3 protein which caused a reduction of global m6A methylation levels, an increase in AML cell differentiation and apoptosis, and reduced the translation of METTL3 target genes, consistent with the effects of METTL3 knockdown. Together, this project describes the establishment of dual-luciferase drug screening platforms and supports the degradation of leukaemia oncoproteins or oncogenic mediator proteins as an innovative therapeutic route to treat acute leukaemia.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Degradation of onco-proteins and oncogenic mediator proteins as a novel approach to treat acute leukaemia |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2022. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > UCL GOS Institute of Child Health UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10154939 |
Archive Staff Only
 |
View Item |
