Combined Effect and Anti-tumor Mechanism of Triptolide and 5-Fluorouracil on HT-29 Cells in Vitro

Objective: To study the effects of triptolide(TPL) and 5-fluorouracil(5-FU) on proliferation and apoptosis of human colon carcinoma cell line HT-29 in vitro.Methods: HT-29 cells were cultured with RPMI1640 medium in regular condition.The inhibition effects were evaluated by MTT assay.The subcellular morphology was observed by transmission electron microscope. Cell apoptosis was detected by flow cytometry.The changes of bcl-2 and p53 in protein level were quantified by immunocytochemistry.Results: ① TPL and 5-FU either combined or alone inhibited significantly the proliferation of HT-29 cells and induced obvious apoptosis.Growth inhibition rate arrived at(94.92 ± 2.76)%,and apoptic rate at 48 h reached(41.71±1.38)%.② The interaction of the two drugs was synergistic(CI1) at lower concentrations.The mechanism may partly attribute to cell apoptosis.③ TPL and 5-FU affected p53 protein expression but did not affect expression of bcl-2 protein.Conclusion: The interaction of TPL and 5-FU was synergistic at lower concentrations.The apoptosis may be dependent on the p53 and independent on bcl2 passway.The result may play an important role in the treatment of colon cancer.