Finding extracellular vesicle biomarkers for oesophageal cancer early detection

Extracellular vesicles (EVs) are entities secreted by cells that can be involved in cell-to-cell communication. They contain messenger proteins and other molecules, which act like ‘instructions’ to recipient cells.  EVs contain proteins both on their inside and outside.

All cells, including cancer cells, release EVs.  EVs from different cell types have slightly different compositions of proteins, which give them the ‘characteristics’ of their parent cell.

Members of the Goberdhan’s lab have previously shown that EVs released by colorectal cancer cells contain different protein when they are subjected to certain types of stress, such as certain nutrient deficiencies.  These ‘switched’ EVs change recipient cell behaviour, for example, increasing cancer cell growth. Researchers can potentially exploit these differences in EV protein composition to define distinct EV sub-populations: a helpful step towards their use as multi-protein biomarkers.

Dr Jennifer Allen and Ms Karen Billington from the Goberdhan lab are now applying this concept to the early detection of oesophageal cancer. Barrett’s Oesophagus is a pre-cancerous condition whereby oesophageal cells become damaged. Over time the damage can increase and cancer can develop.

Monitoring patients with Barrett’s Oesophagus is in place to try and identify when cancer has developed, however this is done through invasive and costly endoscopy, which may miss cancer in the very early stages. There is a need to identify when Barrett’s Oesophagus has progressed using less-invasive methods that can be used more regularly, so that cancer can be caught earlier.

Jen and Karen are investigating the potential of using EV proteins as biomarkers, which could be identified though simple blood tests. They are using different types of cells – such as normal oesophagus cells, Barrett’s Oesophagus cells and Oesophageal cancer cells – to compare the proteins found on the EVs released by each of these cell types.

The team is working with Dr Elizabeth Bird-Lieberman, a Gastroenterology Consultant at the JR Hospital, to collect blood samples from patients with Barrett’s Oesophagus, to see if EV information could be extracted and tested through simple blood tests – such as that being developed by Prof Jason Davis.

The aim is to identify a handful of proteins via proteomic analysis, that allows them to differentiate EVs from oesophageal cancer cells. If the protein biomarkers associated with the more cancerous cell lines can be detected in patient blood samples, Barrett’s Oesophagus patients could then be routinely tested for specific EV proteins that indicate the presence of parent cancer cells. This simple test could be carried out much more regularly than endoscopy surveillance and would enable earlier detection and treatment of oesophageal cancer in these patients.

Colorectal cancer cell extracellular vesicles. These two vesicles have become deflated and have the characteristic cup-shaped morphology caused by preparation for electron microscopy. Images generated by Dr John Mason (DPAG) and Dr Errin Johnson (EM Facility Manager, Dunn School).

About the study

The Goberdhan lab members are interested in intracellular signalling and cell communication. Their major focus is on how this goes wrong in cancer and other major human diseases. Specifically, they investigate:

  1. The role of amino acid sensing and stress-induced signalling in regulating cellular growth and intercellular communication involving exosomes.
  2. The regulation of exosome formation and heterogeneity by intracellular signalling pathways and membrane trafficking.
  3. The effect of exosome signalling on recipient cell behaviour and cancer progression, particularly in response to microenvironmental stresses applied to exosome-secreting cells.

 

This study is funded by the CRUK Early Detection Primer Award.