Endosomal Sorting Complex Required for Transport (ESCRT): Investigation of the role in acquired drug resistance in colon cancer

Despite treatment advances, one of the most common cancers, colorectal cancer (CRC), still has a 45% mortality rate, and one of the major problems is the build-up of resistance to cancer drugs during treatment (‘acquired resistance’) such that over time the drugs stop working. Whilst we have some understanding of acquired resistance mechanisms, there is still clearly much that needs to be discovered. With a greater understanding of the novel mechanisms this could eventually lead to the development of treatments. These therapies could interfere with these novel mechanisms thus increasing the chances of drugs being effective for longer. Preliminary work at Bradford has identified members of the Endosomal Sorting Complex Required for Transport (ESCRT) proteins, which are more abundant in drug resistant CRC cell sublines developed from the parent cell lines by prolonged drug exposure, compared with untreated cells.

Our hypothesis is that ESCRTs have a role to play in the acquisition of drug resistance in colon cancer, and this project will investigate this hypothesis. The project will develop a series of cell lines expressing specific ESCRT family members which have been modified using gene knock-in/-out techniques in the parent line. The acquisition of drug resistance over time in the knockout cell line compared with the wild type cell line will then be assessed. Also important would be to see if alteration in ESCRT machinery expression effects sensitivity to a range of drugs and not just the drug used previously, suggesting involvement of the ESCRTs in a multiple drug resistance phenotype.

The project will also look at the expression of ESCRTs in clinical material from treated and naïve patients to see if the experimental expression patterns are valid in a clinical setting.

In establishing if the cell line model can be utilised as an in vivo experimental model for evaluating therapeutic intervention to modulate acquired drug resistance, mouse xenograft studies will take place in the last year of the project looking at treatment efficacy and effects on protein expression in wild type and altered expression cell lines.

If the hypothesis is proved in this project, then we will look to disseminate the findings in peer-reviewed scientific journals and through attendance at national and international conferences.