Investigating the role of fibroblast ENPP1 expression in shaping the immune microenvironment of chromosomally unstable cancer

Oesophageal adenocarcinoma (OAC), a disease of unmet need, demonstrates high rates of chromosomal instability (CIN).

CIN constitutively activates the cGAS-STING pathway, producing extracellular 2’3’cGAMP which should stimulate host immune cells.

Recently, we identified upregulation of ENPP1 as a key mechanism of immunosuppression in CIN-high cancers, hydrolysing 2’3’cGAMP and increasing adenosine in the tumour microenvironment (TME).

My data support that: - Fibroblast-ENPP1 expression is a mechanism of immune exclusion, upregulated by extracellular vesicles (EVs) from CIN-high cells - ENPP1 correlates with a protumourigenic extracellular matrix (ECM) promoting immunosuppression. This fellowship will identify novel targets mediating immunosuppression in CIN-high OAC.

AIMS (1) How do constitutively cGAS-STING-active CIN-high tumours signal to stromal cells, resulting in ENPP1 upregulation?

EVs from CIN-high and CIN-low cells will be profiled (proteome, miRNA, genome). (2) What influence does CIN-associated fibroblast ENPP1 expression exert on the ECM?

Organoid-fibroblast co-cultures will delineate how fibroblast-ENPP1 influences tissue stiffness, using biomechanical characterisation. (3) Is T-cell exclusion from the TME ENPP1-dependent and fibroblast-specific, and what are the underlying mechanisms?

OAC samples will be characterised (using flow cytometry and digital spatial profiling) identifying fibroblast-ENPP1-regulated immune populations.

Tri-culture models (matched organoid-fibroblast-immune cells) will analyse T-cell reactivity and cytotoxicity regulated by fibroblast-ENPP1 and novel targets.