Synergistic effect of pH-sensitive PEGylated RG3-chitosan prodrug nanoparticles encapsulated celastrol on pancreatic cancer

Celastrol (Cel) is a potential anticancer therapeutic candidate, but its limited practical applicability is due to its low solubility, poor tumor selectivity, and cytotoxicity. Clinically, ginsenoside Rg3 (RG3) is typically combined with chemotherapy to enhance antitumor effects and reduce side effects. Herein, we developed novel pH-sensitive prodrug nanoparticles (NPs) containing RG3 and Cel for the synergistic treatment of pancreatic cancer (PC). Amphiphilic prodrug, a PEGylated chitosan oligosaccharide coupled with RG3 via Schiff base bond, was self-assembled with hydrophobic Cel into NPs with drug loadings of 2.12% (Cel) and 1.63% (RG3). NPs exhibited a suitable particle size of 124.01 nm, zeta potential of -39.89 mV and good physical stability. In addition, NPs also showed a controlled drug release when the Schiff base bonds were hydrolyzed in the acidic environment. In Pan02 tumor-bearing mice, NPs exhibited a high accumulation in tumor tissues and prolonged blood circulation time. Furthermore, NPs could more effectively inhibit tumor growth and reduce systemic toxicity, compared with the free Cel, RG3, prodrug, and Cel + RG3. The results indicated that the NPs could provide a safe and promising nanoplatform for PC therapy.