Impact of Arsenic Trioxide on LS-174T Cell Growth and the Activity of Telomerase

The therapeutic action of arsenic trioxide（ As203 ） on solid tumors has aroused widespread interest among scholars. To study the impact of As2O3 on human colorectal carcinoma cells（ LS-174T cell） and the activity of telomerase, the methods of PCR-ELISA, flow cytometry （FCM） and MTT assay in vitro were utilized. The results show that （1） with an increase in the concentration of As2O3, the ratio of living the cells to dead cells decreases significantly, and the IC50 value is 5.23 μg/mL; （2） the cells of the experimental groups can endure a series of morphological changes similar to the features of apoptosis ; （3） the apoptotic curves of FCM pictures appear after 24 h, and the cells show the apoptosis in a time-dependent manner; （4） As2O3 can inhibit the activity of telomerase of the cell extraction obviously in a concentration-dependent and time-dependent manner after 24 h. It can be concluded from the experiment results in vitro that As2O3 can induce the apoptosis of LS-174T cells and inhibit the telomerase activity. Therefore, it has been proposed, for the first time, that these two factors （the apoptosis of LS-174T cells and the inhibition to the telomerase activity） are important causes of the LS-174T cell death caused by As2O3.