Triptolide Experimental Studies On The Role Of Endometrial Carcinoma Cells

Objective: Triptolide, a diterpene triepoxide, is a purified compound from Tripterygium that has been identified as one of the major components of this herb. It has been reported to be effective in the treatment of autoimmune diseases, especially rheumatoid arthritis. Recently it was reported that triptolide could also induce anti-proliferative and pro-apoptotic activity on many different types of cancer cells in vitro and in vivo. This study investigates the anti-tumor effect of triptolide in human endometrial cancer cells HEC-1B and HHUA in vitro, and elucidates the possible molecular mechanism involved.Methods: Human endometrial cancer cell line HEC-1B and HHUA was cultured in vitro and exposed to various concentrations (5–160ng/ml) of triptolide. MTT was used to examine the effects of triptolide on proliferation of cells; flow cytometric analysis was used to determine the phase of cell cycle and detect apoptotic cells; DNA electrophoresis was used to investigate the apoptosis fracture zone; and the cell'proliferation was observed by microscope.Result: Triptolide notably inhibited the proliferation of HEC-1B and HHUA in a time-dose dependent fashion. MTT assay showed that triptolide is a relatively strong growth inhibitor to HEC-1B cells with an IC50 below 10ng/ml after a 72 h treatment. The effect of triptolide on HEC-1B was higher than that of HHUA. After a 48h treatment, low dose (5ng/ml) triptolide arrested HEC-1B cell cycle at S phase; high dose (40/80ng/ml) triptolide arrested HEC-1B cell cycle at G2/M phase and HHUA cell cycle at S phase respectively. Higher concentrations of triptolide led to apoptosis as indicated by the appearance of a subG1 peak. In HEC-1B cells, 48h triptolide treatment resulted in inter-nucleosomal DNA cleavage as indicated by DNA laddering after agarose gel electrophoresis.Conclusion: Triptolide has significant suppressive effect on endometrial cancer line HEC-1B and HHUA in vitro, and its works in a low concentration and a dose-time dependent fashion. The inhibit effect of triptolide on HEC-1B was higher than that of HHUA. The anti-tumor effect of triptolide may be achieved by blocking cell cycle at S phase and G2/M phase, and induces the cell apoptosis.