Investigation of doxorubicin resistance in MCF-7 breast cancer cells using shot-gun comparative proteomics with proteolytic 18O labeling.

A shot-gun comparative proteomic investigation utilizing proteolytic 18O labeling has been carried out on a drug susceptible MCF-7 human breast cancer cell line and a related cell line that is resistant to doxorubicin. The proteolytic 18O labeling method has been further refined and optimized for application to a protein fraction stemming from the cytosol of the breast cancer cells. The comparative investigation revealed several proteins with altered expression levels in the doxorubicin resistant line. These altered proteins are considered for a possible role in doxorubicin resistance.