Abstract
Chimeric antigen receptor (CAR) T cell therapy represents a step-change improvement in outcomes for patients with treatment-resistant haematological malignancies. Despite this success, these results have not been replicated when CAR T cells are directed against solid tumours. The reasons for this are multifactorial, however clinical trials consistently report that a small minority of patients treated with CAR T cells for solid tumours will achieve favourable clinical responses. This suggests that while current CAR T cell designs are insufficient for treating solid tumours, there remains scope for optimisation that will improve the efficacy of this therapy. In line with this concept, multiple different ‘armoured’ CAR T cell designs have been described that aim to overcome the factors that limit CAR T cell anti-tumour activity.The work in this thesis describes efforts to genetically manipulate the metabolism of CAR T cells in order to improve their anti-tumour activity. Initially, the aim of these efforts was to enhance T cell oxidative phosphorylation (OXPHOS) in order to promote the persistence of CAR T cells after adoptive transfer. Knockdown of the metabolic regulatory proteins Drp1 or Rictor failed to achieve this, however expression of a constitutively AMPK mutant was successful at enhancing OXPHOS in CAR T cells. Despite this, no improved anti-tumour activity was observed by CAR T cells expressing this AMPK mutant, possibly due to the absolute requirement for T cells to conduct anaerobic glycolysis to fuel effector functions.
As an alternative approach, efforts were made to enable CAR T cells to overcome metabolic competition for low glucose concentrations in the solid tumour microenvironment (TME). In vitro modelling of CAR T cell effector functions at low glucose concentrations revealed that key effector functions are inhibited by low glucose concentrations mimicking those found in the TME. Attempts to armour CAR T cells to overcome this by overexpressing glucose transporters or glycolytic enzymes were unsuccessful, however two approaches to engineer CAR T cells to utilise an alternative carbon source (ACS) to glucose, trehalose and fructose, were successfully validated in vitro. These data provide the foundation for future work to demonstrate that engineering CAR T cells to metabolise an ACS to glucose will result in improved anti-tumour activity in in vivo human tumour models.
| Date of Award | 1 Apr 2022 |
|---|---|
| Original language | English |
| Awarding Institution |
|
| Supervisor | Sophie Papa (Supervisor) & Esperanza Perucha (Supervisor) |