[Teniposide inducing apoptosis and G2/M phase arrest of Tca8113 cells]

The present study is designed to identify quantitatively the in vitro effect of VM-26 against oral squamous cell carcinoma Tca8113 and to explore the underlying mechanism.

Human tongue squamous cell carcinoma cell line Tca8113 was used as subject. Cells were incubated with VM-26 of various concentrations for a variety of time spans. Cisplatin (CDDP) was employed as a control agent. MTT assay was used to assess the inhibition of cell growth by VM-26. Flow cytometer (FCM), transmission electron microscope (TEM) and fluorescence staining were employed for determining the apoptotic rate of cells induced by VM-26. Cell cycle distribution of Tca8113 cells incubated with VM-26 was examined through flow cytometer assay. SAS 6.12 was used for one-way ANOVA.

The IC50 of VM-26 against Tca8113 cells was 0.35microg/ml and that of CDDP was 1.1microg/ml. The changes in morphology and ultrastructure of Tca8113 cells were observed using fluorescence microscope and TEM, and apoptotic morphological feature could be found in the nucleus. Apoptotic rate of Tca8113 cells incubated with VM-26 of 5.0microg/ml for 72 hours was 81.01% and cell cycle appeared was arrested at S phase. However, exposed to VM-26 of 0.15microg/ml for 72 hours, Tca8113 cells in the G2/M phase increased from 12.75% to 98.71%, while the apoptotic rate of these cells was 17.38% and far below than that of cells treated with VM-26 of 5.0microg/ml.

VM-26 could significantly induce apoptosis of oral squamous cell carcinoma cells and inhibit cell growth. There may be another pathway to induce apoptosis of oral squamous cell carcinoma cells except for G2/M phase arrest. Supported by National Natural Science Foundation of China (30300388, 30171014, 30330580) and Research Grant (No.036505013, 034107002) of Science and Technology Committee of Shanghai Municipality.