Proteomic analysis of differentially expressed proteins in 5-fluorouracil-treated human breast cancer MCF-7 cells.

5-Fluorouracil (5-Fu) is a commonly used chemotherapeutic agent in clinical care of breast cancer patients. However, the mechanism of how the 5-Fu works is complex and still largely unknown. The objective of this study was to understand the mechanism further and explore the new targets of 5-Fu. The differentially expressed proteins induced by 5-Fu in human breast cancer MCF-7 cells were identified by proteomic analysis. Four differentially expressed proteins were validated using Western blot and quantitative real-time reverse-transcription polymerase chain reaction analysis for protein and mRNA levels. The effect of 5-Fu on MCF-7 cells was determined by cell viability assay, transmission electron microscopy and flow cytometry analysis. 5-Fu dose-dependently inhibited cell proliferation with the IC50 value of 98.2 μM. 5-Fu also induced obviously morphological change and apoptosis in MCF-7 cells. Twelve differentially expressed proteins involved in energy metabolism, cytoskeleton, cellular signal transduction and tumor invasion and metastasis were identified. These results may provide a new insight into the molecular mechanism of 5-Fu in therapy of breast cancer.