Utilising tissue-on-a-chip technology as an ex vivo model of breast cancer metastatic colonisation

Lead Research Organisation: University of Hull
Department Name: Biomedical Sciences

Abstract

Breast cancer kills over 11,000 women each year in the UK. Virtually all of these women die because their breast cancer cells travel to other organs within the body such as the liver, lungs, bones and brain, where they grow into new tumours and stop the organs from working. Therefore, one way to stop women dying from breast cancer is to prevent breast cancer cells from growing in other organs. Currently, however, we do not understand how breast cancer cells move to and grow in other organs, so we are not able to prevent it with drugs.

Most studies trying to understand how breast cancer cells grow in different organs take place in mice. However this is not an ideal way to study the process, as it is very difficult to watch cancer cells growing inside a mouse. To get around this, large numbers of mice are used for each experiment with some being killed at different time points and the cancer cell spread to other organs then determined. This uses a lot of mice, and still does not allow us to see exactly what happens when cancer cells are growing in these organs.

Replicating the growth of breast cancer cells in other organs in a laboratory dish would be a way to better understand this process, whilst also reducing the number of mice used in research. Previous work has attempted to do this, however the laboratory systems which have been created lack the complexity of cancer cell growth seen in patients, so uptake amongst researchers has been low.

We have identified a model already in use which has the potential to be used to study breast cancer growth in other organs. This model has been developed at the University of Hull, and is called "tissue-on-a-chip". Tissue-on-a-chip involves taking a small amount of tissue from either a mouse or a human, and keeping it alive in a glass or polymer chip constantly supplied with flowing nutrients. These chips have previously been used to study both normal tissue and tumour tissue, and here we propose to study how breast cancer cells grow in other organs. Tissue from liver, a common site for breast cancer spread, will be placed inside the chips, and then cancer cells from breast tumours will be slowly flowed across and allowed to bind to and invade the liver. This will be monitored using powerful microscopes.

We believe that the successful development of this model could be of great use to scientists working to understand how cancer spreads. We have therefore designed this project firstly to adapt the technology for study breast cancer cells growing in other organs, and secondly to showcase its potential to other scientists. To adapt the tissue-on-a chip technology to study cancer spread we will transfer it to the University of Manchester, where we can use world-class facilities to watch cancer cells as they grow. We will also demonstrate how this technology can be used to test drugs to prevent cancer cells growing in other organs by adding different drugs, and seeing if we can prevent cancer cells from growing. As this technology is being established, we will begin discussions with other scientists across the UK to ensure that people know about this model, and will actively promote the benefits to their research alongside significantly reducing number of mice used in research.

Technical Summary

We aim to reduce the number of mice used in metastasis research by developing a novel ex vivo model to study metastatic colonisation. This tissue-on-a-chip model incorporates whole tissue pieces to model the metastatic microenvironment, combined with microfluidic channels to model the arrival of cancer cells at the metastatic organ, making it more physiologically relevant than in vitro models currently in existence. This technology has been extensively developed by Prof Greenman and Dr Green in a multi-disciplinary partnership at the University of Hull, and it is currently used for studies of tumour tissue determining response to chemo- and radiotherapy as a way of customising patient treatment.

In this project, we will transfer the technology to a new application: cancer metastasis. Initial experiments will take place in Hull to optimise conditions required for breast cancer cell colonisation. Colonisation will be monitored by immunohistochemical staining for human cytokeratin 19, in combination with an assessment of tissue viability by calcein-AM and PI staining and lactate dehydrogenase released from tissue effluent. Following optimisation of colonisation, the technology will be transferred to Dr Eyre at The University of Manchester. This new location will allow us to further develop the technology using advanced imaging and histological techniques available within the CRUK Manchester Institute. We will use confocal microscopy combined with second harmonic imaging to visualise cancer cells and surrounding tissue structures during colonisation, followed by automated multiplex immunofluorescence and multicolour slide scanning to determine metastatic niche cells associating with cancer cells during colonisation. Finally, we will demonstrate the application of this technology as robust method for screening anti-metastasis drugs, by perfusing candidate drugs into the microfluidics, and assessing the effect of these on cancer cell colonisation.

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