Abstract: Purpose: To study whether sesquiterpene lactones(SLs) have the inducible apoptosis effect on human nasopharyngeal carcinoma (NPC) and it's relation with the mechanism of caspase activation, Methods: NPC cell line (CNE1) was treated with parthenolide(PN),the principal active component of SLs. The apoptotic cell death was indicated by morphological alterations. The inducible apoptosis and cytotoxicity effect were determined by flow cytometry, and the cellular caspase－9 and caspase－3 activity was measured by a spectrofluorometric method. Results: The TUNEL positive cell (％) and the SubG1 (％) of cell cycle distribution in creased in PN treated group. Compared with the negative control, there were significant increases of detached cell ratio (％) and lactate dehydrogenase (LDH) leakage (％). However, after PN treatment, the activities of caspase－9 and －3 were not significantly increased. Combined with caspase inhibitors in blocking experiment, PN decreased the caspase－9 and －3 activity but not the apoptotic and cytotoxic index. Conclusion: It was indicated that PN is able to induce apoptosis of CNE1 cell, which may be correlated with cytotoxicity effects but not with caspase cascade activation.

Key words: nasopharyngeal neoplasms, parthenolide, apoptosis, caspase