Targeting NAD+ metabolism in ovarian cancer
File(s)
Author(s)
Gruet, Michael
Type
Thesis
Abstract
Ovarian cancer is the fourth leading cause of female cancer related deaths in the developing world. Epithelial ovarian cancer is the most common type of ovarian cancer, and patients with these tumours are frequently treated with poly(ADP-ribose) polymerase inhibitors. Patients with a homologous recombination deficiency, for example due to mutation in genes such as BRCA1/2, benefit most from treatment with PARP inhibitors. However, in recent years it has been shown that HRD-negative populations can also benefit. Mutations that dysregulate RAS/PI3K-signalling frequently occur in epithelial ovarian cancer, and recent clinical trials have shown that this can promote PARP inhibitor resistance. Since dysregulated RAS/PI3K-signalling promotes metabolic reprogramming to support unconstrained proliferation, we investigated whether these mutations could create a targetable “metabolic bottleneck” that could extend the benefit of PARP inhibitors in these RAS/PI3K-mutant tumours. In this thesis, I characterised the role of the NAD+ salvage pathway enzyme NAMPT in EOC and found that RAS/PI3K-mutant tumours are exquisitely sensitive to a NAMPT inhibitor. Importantly, RAS/PI3K-mutations increase the sensitivity of EOC cell lines to a synergistic NAMPT and PARP inhibitor combination in vitro. This combination significantly improved in vivo survival outcomes in ID8-Trp53-/-; Pten-/- tumours, an alteration that occurs in the most common subtype of EOC, high grade serous ovarian cancer. Using RNA-sequencing we provide novel insights into the role of PARP and NAMPT activity on alternative splicing events in a HGSOC background. Finally, using metabolomics we optimise conditions to successfully utilise “clickable” pre-cursor NAD+ probes to detect PARPs post-translational modification, ADP-ribosylation, by chemical proteomics.
Version
Open Access
Date Issued
2023-11-17
Date Awarded
01/04/2024
License URL
Advisor
Keun, Hector
Tate, Ed
Sponsor
Cancer Research UK
Grant Number
PS3555_WSCC
Publisher Department
Chemistry
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)