Cytotoxicity of Triptolide and Triptolide loaded polymeric micelles in vitro

Triptolide (TP), a diterpenoid triepoxide purified from the Chinese herb Tripterygium wilfordii Hook F is characterized by strong anti-tumor effects on various cancer cells. Except its anti-tumor effects, TP also shows multiple pharmacological side activities, such as anti-inflammatory, immune-suppressive and male anti-fertility. In order to reduce these side effects, especially the immuno-suppressive activity when used to cure cancer, a novel polymeric micelle system containing TP (TP-PM) was constructed. The immune-modulation effects of TP-PM have been evaluated by previous studies. In this study, we compared the cytotoxicity of TP and TP-PM on Jurkat and HT29 cells. Therefore, we determined the cell viability, membrane integrity, cell proliferation, apoptosis, and caspase 3/7 activity after exposure to TP and TP-PM. The results demonstrated that actually low concentrated TP and TP-PM could induce an inhibition of cell growth and proliferation as well as membrane damage in both tumor cell lines. TP and TP-PM induced apoptosis and caused activation of caspase 3/7 even at low concentrations. Both formulations destroyed the membrane of Jurkat cells, nevertheless, TP-PM showed stronger pernicious effects. In general, TP-PM induced in both tested cell lines stronger effects than TP. Therefore, polymeric micelles can be considered as promising carriers for TP in cancer therapy.