Triptolide combined with cyclopamine loaded in polymeric micelles: molecular dynamics, preparation and in vitro antitumor activities

Abstract

Both triptolide (TP) and cyclopamine (CPA) exhibit strong anticancer effects in vitro with adverse reactions and low bioavailabilities because of their water insolubility and poor liposolubility. The preparation of functional polymer materials into micelles not only improved the apparent solubility of the drug, changed the release behavior of the drug, but also made the drug targeted. All-atom molecular dynamics (MD) methods were used to simulate the states of both TP and CPA in PLA-PEG block copolymer micelles. MD results showed that TP and CPA were concentrated in the core layer of micelles formed by PLA-PEG block copolymers. The polymers PLLA-PEG-COOH were synthesized using HO-PEG-COOH and PLA and characterized by FTIR, 1H NMR, 13 C NMR, and gel chromatography. The dual drug-loaded polymeric micelle ((TP + CPA)-PM) was prepared by solvent evaporation, and the encapsulation rates of TP and CPA were 65.44% and 78.16% using the HPLC method, respectively. The polymer micelles were nearly spherical and did not aggregate under transmission electron microscopy (TEM), and the particle size was about 75.32 ± 0.20 nm through dynamic light scattering (DLS). (TP + CPA)-PM showed similar inhibitory effects to free drugs on A2780, A549, HepG2, and SKOV3 cells, which was proved by the MTT proliferation inhibition experiment, Hoechst33258 fluorescence staining experiment, and flow cytometry experiment. These results appeared to support the assumption that polymeric micelles encapsulation did not affect drug activity. PLA-PEG block copolymer may be a promising drug delivery vehicle for loading TP and CPA in antitumor therapy.