Induction of apoptosis in human nasopharyngeal carcinoma cell line CNE-2Z by tubeimosides

AIM To investigate whether tubeimosides induce apoptosis in CNE-2Z. METHODS Growth inhibition by tubeimosides was measured using MTT assay. The effect of tubeimosides on apoptosis induction of CNE-2Z cell line was studied by the fluorescent microscopy, electronic microscopy, DNA agarose gel electrophoresis, flow cytometry analysis. Western blotting was performed for detecting the apoptosis-related gene. RESULTS The growth of CNE-2Z cells was inhibited obviously by tubeimosides. CNE-2Z cells showed typical apoptotic features observed by fluorescent microscopy, electronic microscopy. DNA fragmentation into multiples of low molecular weight DNA(180～200 bp) was detected by agarose gel electrophoresis of DNA; Sub-G 1 peak was found by flow cytometry analysis, and the apoptosis index was 58 0%. The expression of bcl-2, inhibitor of apoptosis, decreased apparently; while that of bax, inducer of apoptosis, increased notably at 1, 3, 5 h after the addition of tubeimosides. The cleavage of caspase-3 was noticed at 1, 3, 5 h after the treatment of tubeimosides. CONCLUSION Tubeimosides could induce the apoptosis of CNE-2Z cells. The induction of apoptotic by tubeimosides was closely associated with bcl-2, bax and caspase-3.