Tumour niche cross-talk; targeting mesenchymal cancer drivers

Epithelial cancers represent 85-90% of all tumours. Traditional studies have centred their attention on the mutation burden associated with tumorigenesis and cancer. However, increasing evidence suggests that the tumour microenvironment (TME) plays a crucial role in the pathogenesis and progression of carcinomas. Tumour associated fibroblasts (TAFs) are the commonest cell type in the TME in many cancers including breast, pancreas and liver. These TAFs have the potential to change the behaviour of epithelial cells, promoting the formation and progression of cancer. However, how TAFs influence the behaviour of epithelial cells is still poorly understood. This project investigates the critical mechanisms by which TAFs modulate epithelial cell behaviour from early stages in tumour development (epithelial-mesenchymal cross-talk). The study will be performed in established mouse models of oesophageal tumorigenesis, revealing lesions from as early as 10 cells in size.
During the first and second year, 10 relevant proteins and secreted molecules will be selected from pre-existing proteomic and secretomic datasets. These selected targets will then be validated in vitro using 3D organotypic culture systems and insert culture systems, and any changes in the behaviour (proliferation migration assays, differentiation, lineage tracing) of normal and tumour epithelial cells, and normal and tumour fibroblasts will be assessed. Inhibitors will also be added to in vitro culture systems to see whether the lesion phenotype can be rescued.
Furthermore, the importance of those highly expressed secreted molecules may extend to their identification in liquid biopsies and therefore potentially be used as early cancer biomarkers in patients. These molecules will also be checked to see whether they can be detected in urine or plasma samples from control or diethylnitrosamine (DEN) treated mice, either by performing proteomics on liquid biopsies, or by performing Western blots, ELISAs and targeted proteomics.
During the third year, the clinical relevance of identified proteins and secreted molecules from year 1 and 2 will be validated in human primary cells using 3D culture systems, and in vivo xenograft models. Two separate approaches will be used to determine the influence of these proteins and secreted molecules on murine tumour growth. Firstly, mice will be treated with selective drugs that inhibit the targets of interest and secondly mice that have had the target of interest disrupted or knocked out will be investigated. Human cells will also be grown in 3D culture systems and treated with recombinant proteins, inhibitors, or CRISPR/Cas9 techniques will be performed to target pathways identified in mice to see if they alter the behaviour of the human cells (proliferation, migration assays, differentiation, lineage tracing). Moreover, human samples will be used to see whether previously identified secreted molecules from mice blood and urine (year 2) are also found in human blood and urine.
The milestones of the project are 1) to understand how tumour cells interact with their supporting neighbouring cells (i.e. TAFs), (2) to determine the molecular networks controlling epithelial-mesenchymal cross-talk and study their relevance for tumour formation, (3) to identity alternative therapeutic strategies that may synergise and potentiate existing treatments, and (4) to identify potential novel diagnostic biomarkers.