Assessment of PRMT5 inhibition as a therapeutic strategy for Wilms’ Tumour.

Abstract

Wilms’ Tumour is the most common paediatric renal malignancy that accounts for 85% of all paediatric renal tumours. MYCN has been documented to be overexpressed in Wilms’ Tumour and mutations such as copy number gain are associated with a high relapse rate in high-risk blastemal Wilms’ Tumour. However, due to MYCN’s undruggable structure and its complex protein-protein dynamics, attempts to target MYCN have been a challenge. Here, both depletion via small interfering RNA and inhibition via small molecule inhibitor of protein arginine methyltransferase 5 (PRMT5) led to impaired growth and increased apoptosis in Wilms’ Tumour cell lines, WiT49 and 17.94. Inhibition of PRMT5 activity using GSK591 has also resulted in decreased MYCN protein and transcript levels. Additionally, PRMT5 inhibition has also led to a reduction in MYCN targets such as EZH2 at the protein and RNA levels in both WiT49 and 17.94 cells. These results suggest that PRMT5 may be able to modulate the expression of both MYCN and MYCN targets, indicating that a PRMT5/MYCN/EZH2 oncogenic axis might contribute to Wilms’ Tumour. Furthermore, quantitative gene transcription analysis and immunoblotting of the WiT49 cell line suggested that inhibition of PRMT5 using GSK591 has also led to the re-expression of anti-apoptotic protein BCL2. This was not observed with the 17.94 cell line, suggesting that GSK591 may have variable effects depending on the cell lines used. Interestingly, a combination treatment targeting both PRMT5 and BCL2 has worked synergistically to induce apoptosis in both Wilms’ Tumour cell lines. This finding is promising as it may serve as a novel approach in treating Wilms’ Tumour that is heterogenous in nature. Together, this study has shown that PRMT5 may be a therapeutic target in Wilms’ Tumour and a combination treatment targeting both PRMT5 and BCL2 protein using small molecule inhibitors could represent a promising treatment method for Wilms’ Tumour.

Date of Award	3 Oct 2023
Original language	English
Awarding Institution	University of Bristol
Supervisor	Karim T A Malik (Supervisor) & Stefan G E Roberts (Supervisor)