As cancer patients are treated with any of the wide range of current anti-cancer drugs, the cancer cells adapt and become "drug-resistant" to be better able to survive. Drug resistance is a major problem in cancer treatment, even for the newest of our drugs. The cancer does this in a way that often confers resistance to several drugs at once, a phenomenon referred to as "multi-drug resistance".

This adaptation process also changes the nature of the overall cancer, as the cancer cells are selected and/or change in response to this exposure to drug(s). They become more able to move, invade, and eventually migrate to other locations in the process known as metastasis. We are studying the sequence of events within the cell as the cancer develops both resistance to the drug and a more aggressive nature. The two phenomena seem linked.

We are using a series of cell populations that reflect this dual change in behaviour. We expose colorectal cancer cells to increasing concentrations of the drugs that are used to treat this cancer - 5-fluorouracil, oxaliplatin and irinotecan. We track the changing behaviour using methods to reveal the form of drug resistance - one tactic that the cancer cells use is to accumulate large amounts of a ''pump'' that expels the cancer drug from the cell before it can do too much damage. We then examine how the cells behave.

Our ultimate goal is to find out how to interfere with the process by which cancer cells become more threatening to the health and well-being of the cancer patient.