Background: A sequential release co-delivery system is an effective strategy to improve anti-cancer efficacy. Herein, multicomponent-based liposomes (TET-CTM/L) loaded with tetrandrine (TET) and celastrol (CEL)-loaded coix seed oil microemulsion (CTM) were fabricated, which showed synergistic anti-liver cancer activities. By virtue of Enhanced Permeability and Retention (EPR) effect, TET-CTM/L can achieve efficient accumulation at the tumor site. TET was released initially to repair abnormal vessels and decrease the fibroblasts, and CTM was released subsequently for eradication of tumor tissue.
Methods: TEM (transmission electron microscopy) and DLS (dynamic light scattering) were adopted to characterize the TET-CTM/L. Flow cytometry was adopted to examine the cellular uptake and cytotoxicity of HepG2 cells. The HepG2 xenograft nude mice were adopted to evaluate the anti-tumor efficacy and systemic safety of TET-CTM/L.
Results: TEM images of TET-CTM/L showed the structure of small particle size of CTM within large-size liposomes, indicating that CTM can be encapsulated in liposomes by film dispersion method. In in vitro studies, TET-CTM/L induced massive apoptosis toward HepG2 cells, indicating synergistic cytotoxicity against HepG2 cells. In in vivo studies, TET-CTM/L displayed diminished systemic toxicity compared to celastrol or TET used alone. TET-CTM/L showed the excellent potential for tumor-targeting ability in a biodistribution study.
Conclusion: Our study provides a new strategy for combining anti-cancer therapy that has good potential not only in the treatment of liver cancer but also can be applied to the treatment of other solid tumors.

Keywords: celastrol, tetrandrine, sequentially released liposomes, anti-liver cancer