OBJECTIVETo investigate the differentially expressed mitochondrial proteins in hydroxycamptothecin (HCPT)-treated SMMC-7721 cells by comparative proteomic analysis.

METHODSApoptosis of SMMC-7721 cells were induced by using HCPT and their mitochondria were isolated with a mitochondria isolation kit for cultured cells. Three different solubility protein fractions were extracted with ReadyPrep Sequential Extraction Kit and were separated by two-dimensional gel electrophoresis (2-DE). PDQuest software was used to differentiate mitochondrial proteins between control cells and HCPT-treated cells. Matrix assisted laser desorption/ionization time of flying mass spectrometry (MALDI-TOF-MS) was used to identify some of the different proteins.

RESULTSHighly purified mitochondria and high resolution 2-DE patterns of the proteins were obtained. Forty-four mitochondrial protein spots from the HCPT-treated cells showed different expressions compared to those of the control cells. Twenty of the different protein spots were analyzed by MALDI-TOF-MS.

CONCLUSIONDifferently expressed mitochondrial proteins in HCPT-treated cells and control cells were obtained in this study. This will be of help to understand the mechanism by which HCPT induces cell apoptosis.