Background: LA67 is a derivative of triptolide that exhibits strong antitumor activity. This derivative has a better safety profile than triptolide, but is limited by poor aqueous solubility.
Aim and Methods: To improve solubility and further increase therapeutic efficacy, we prepared LA67-loaded polymeric micelles (LA67-PMs) using a film hydration method. The physicochemical properties of LA67-PMs were investigated, and the antitumor activity of this formulation against Colon26 (C26) cancer cell line was evaluated in vitro and in vivo with LA67 as a control.
Results: Polymeric micelles containing LA67 had a particle size of 17.88 nm and a drug entrapment efficiency of 94.84%. This formulation dispersed completely in aqueous solution and exhibited slow, sustained release of LA67. Cellular uptake assay showed that LA67-PMs delivered LA67 to cancer cells with greater efficiency than free LA67, which resulted in increased LA67 accumulation in cancer cells. Cell counting kit 8 (CCK-8) assay showed that blank polymeric micelles (PMs) exhibited low toxicity and LA67-PMs exerted pronounced anti-proliferation effects against C26 cells. Furthermore, LA67-PMs induced apoptosis and repressed migration more effectively than free LA67. In vivo evaluation of antitumor activity showed that LA67-PMs inhibited tumor growth and distant organ metastasis to a greater extent than LA67, which resulted in improved survival rate. The potential mechanisms of these effects may have been induction of apoptosis, inhibition of cell proliferation, and neovascularization.
Conclusion: Our study showed that LA67-PMs may be a promising formulation for treatment of colon cancer.
Keywords: triptolide derivatives, polymeric micelles, small size, tumor therapy