Evaluating the role of choline acetyltransferase (ChAT) in T cell malignancies

​​Acetylcholine (ACh) is a classical neurotransmitter increasingly recognized for its immunoregulatory roles. Beyond neural tissues, activated T cells express choline acetyltransferase (ChAT), enabling the local synthesis and release of ACh, which acts through nicotinic and muscarinic receptors to modulate activation, cytokine production, and vascular tone. While this pathway can dampen inflammation and sustain immune homeostasis, its function within malignant T cells remains poorly understood. PTEN loss, a hallmark of aggressive T cell malignancies, constitutively activates the PI3K-Akt pathway to promote unchecked growth and survival. We hypothesized that tumour-intrinsic ChAT restrains these Akt-dependent stress responses, serving as an intrinsic brake on malignant progression. Using a conditional T cell PTEN-deficient mouse model, we found that ChAT is upregulated at specific thymocyte developmental stages that coincide with PI3K Akt hyperactivation, and that ChAT-positive thymocytes in the pre-malignant PTEN-deficient setting display higher activation marker expression and a more activated developmental phenotype compared to ChAT-negative cells. Loss of ChAT in the PTEN-null background further increases pAkt levels and alters early activation markers, which is consistent with a shift toward heightened oncogenic stress. Functionally, deleting T cell-specific ChAT in this model shortens lymphoma survival in an allele dosage-dependent manner, indicating that endogenous cholinergic activity provides a measurable constraint on tumour aggressiveness. Together, these findings support a model in which cholinergic signalling intersects with oncogenic PI3K Akt activity in T cell malignancy. This proposal will define the cellular, molecular, and therapeutic relevance of this interaction, with the overall goal of identifying cholinergic pathways as new entry points for modifying tumour evolution in PTEN-deficient T cell cancers.