Proteomic analysis of cellular response to microcystin in human amnion FL cells

Microcystins (MC), the potent inhibitor of protein phosphatase 1 and 2A, are hepatotoxins of increasing importance due to its high acute toxicity and potent tumor promoting activity. So far, the exact mechanisms of MC-induced hepatotoxicity and tumor promoting activity have not been fully elucidated. To better understand the mechanisms underlying microcystin-RR (MC-RR) induced toxicity as well as provide the possibility for the establishment of biomarkers for MC-RR exposure, differential proteome analysis on human amnion FL cells treated by MC-RR was carried out using two-dimensional gel electrophoresis (2-DE) followed by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry. Image analysis of silver-stained 2-dimensional gels revealed that 89 proteins showed significant differential expression in MC-RR treated cells compared with control, and 8 proteins were unique to MC-RR treated cells and 8 proteins were only detected in control cells. Sixty-six proteins were further identified with high confidence by peptide mass fingerprinting. Some of the identified differentially expressed proteins have clearly relationship with the process of apoptosis, signal transduction, and cytoskeleton alteration which are consistent with the literature. The functional implications of alterations in the levels of these proteins were discussed. However, most of which have not been reported previously to be involved in cellular processes responded to MC-RR. Therefore, this work will provide new insight into the mechanism of MC-RR toxicity.