Manipulating cholangiocarcinoma immune-phenotype in a patient derived precisioncut tumour model to improve immune checkpoint inhibition response.

Cholangiocarcinoma (CCA) is an aggressive cancer type, and its incidence and mortality are increasing globally. Patient prognosis remains poor, with immunotherapeutic approaches such as immune-checkpoint blockade (ICB) in combination with conventional chemotherapy showing a significant benefit in only a small proportion of patients. Further work looking into the tumour microenvironment (TME) in CCA is necessary in order to better understand the mechanisms of therapy response/ resistance. ICB-mediated anti-tumour responses rely on the function of cytotoxic T-cells to target and destroy tumour cells. Immune 'hot' tumours have increased CD8+T-cell infiltration and, thus, improved ICB therapy response, whereas, immune 'cold' tumours show reduced cytotoxic T-cell infiltration and have high levels of immunosuppressive immune cells (e.g. tumour-associated macrophages and T-regulatory cells). The poor response to ICB therapy suggests many CCA tumours have a 'cold' immune phenotype. Combination strategies that modulate tumour immune-phenotype from 'cold' to 'hot' could significantly increase ICB clinical-effectiveness and remains an underexplored area in CCA research. The main aim of this project is to evaluate human patient-derived CCA precision-cut tissue slices (hPCTS) as an ex-vivo model to investigate approaches to augment the TME, determine response/ resistance to immunotherapy and test novel combination therapies. The first objective of the project will be to augment the CCA TME and establish an immune 'hot' phenotype in CCA hPCTS through pharmacological inhibition of immunosuppressive cell types such as tumour-associated macrophages and myeloid-derived suppressor cells. The next step will be to determine whether an immune 'hot' PCTS TME increases ICB response by exposing immune 'hot' and control hPCTS to ICB inhibitors as monotherapy or in combination with conventional chemotherapy and assessing their viability. Finally, immunoproteomic predictive biomarkers of response/ resistance to ICB will be established through in situ digital spatial profiling. Overall, this project aims to augment the CCA hPCTS TME and assess responses/ resistance to various immunotherapeutic/ chemotherapeutic regimes, which has potential to improve ICB response in CCA patients. Simultaneously, this work will further the exploration of immunotherapy response/ resistance mechanisms and the identification of corresponding predictive biomarkers. The hope is that this model will also eventually replace the need for animal experiments in this field of immuno-oncology, which are expensive, raise ethical concerns, and are unable to fully recapitulate the human TME and human disease.