Objective：To investigate the antitumor mechanism and compare the antitumor effect of triptolide (TP) and triptolide loaded polymeric micelles (TP-PM) in HT29 cell, and evaluate the feasibility of polymeric micelle as triptolide nanocarrier.
Methods：HT29 cells were incubated with TP and TP-PM for 24h, 48h and 72h, then, cell viability was measured by WST-1 assay; cell membrane integrity was measured by LDH assay, and cell proliferation was measured by BrdU assay. Additionally, cell survival and apoptosis was measured by FDA-PI staining, and caspase 3/7 activity was measured by Caspase-Glo 3/7 assay kit.
Results： HT29 cell viability and proliferation was apparently inhibited by the TP and TP-PM, the inhibitions showed a time-dependent and dose-dependent manner, and the inhibitory effect of TP-PM was better than TP (P＜0.05). Both TP and TP-PM caused only slight HT 29 cell membrane damage. FDA-PI staining results indicated that FDA-positive cell showed a time-dependent and dose-dependent down trend, while PI-positive cell show a time-dependent and dose-dependent ascending trend. FDA, PI double negative cell also increased more, however, it neither showed a time-dependent nor dose-dependent effect. HT29 cell caspase 3/7 activity increased after incubated with TP and TP-PM, and TP-PM induced a higher apoptosis than TP (P＜0.05).
Conclusions：Both TP and TP-PM can potently inhibit HT29 cell growth and proliferation via induction of apoptosis,  TP-PM shows a better inhibitory effect than TP. Polymeric micelle is a promising drug carrier.