Summary

As tumours grow, they can also spread around the body, which is the main cause of cancer-related death and a major problem for patients becoming resistant to therapy. This tumour spreading is known as metastasis, which is a highly complex process where tumour cells have to cross many barriers to reach a secondary site in the body.

One of these routes of spreading is through blood vessels, where they have to cross the lining of the vessels made up from a type of cells called endothelial cells. Tumour cells have adapted ways to help them cross this barrier, from responding to directional cues to attract them to and cross vessels.

In order to study this process, which is very complex, scientists require tools to investigate important factors governing this. One of which is an ‘organ-on-a-chip model’, which recapitulates a simpler scenario of blood vessel crossing, outside of the body. This comprises of a small chip which can be layered with endothelial (blood vessel) cells, where tumour cells can then be ‘put to the test’ to cross it. Scientists can then study mechanisms of how tumour cells cross these barriers, and if they need help from surrounding cells, such as immune cells, which can also be layered into these chip models.

By altering conditions in a controlled manner, we can find out important mechanisms that help tumour cells combat such barriers in addition to signalling programs they rely upon to withstand the stress from the flow of fluidics that mimic the blood flow you would find in the body. These chips offer the chance to study vessel crossing without excessive use of animal models, and are crucial to gain important information about metastasis.