A multiple environment-sensitive prodrug nanomicelle strategy based on chitosan graftomer for enhanced tumor therapy of gambogic acid

A novel multiple environment-sensitive polymeric prodrug of gambogic acid (GA) based on chitosan graftomer was fabricated for cancer treatment. Folic acid-chitosan conjugates was complexed with thermosensitive amine terminated poly-N-isopropylacrylamide (NH2-PNIPAM) to develop FA-CSPN. Gambogic acid was conjugated with the graftomer via esterification to achieve high drug-loading capacity and controlled drug release. The resulting amphiphilic prodrug, O-(gambogic acid)-N-(folic acid)-N'-(NH2-PNIPAM) chitosan graftomer (GFCP), could self-assemble into micelles. As expected, the micelles were stable and biocompatible, featuring pH-, esterase- and temperature-dependent manner of drug release. Moreover, the anticancer effect studies of GFCP micelles were performed using a tumor-bearing mouse model and cellular assays (tumor cell uptake assay, cytotoxicity and tumor-sphere penetration). Collectively, GFCP micelles show both potential in vivo and in vitro in improving the anticancer effectiveness of GA owing to high loading capacity, targeted tumor accumulation, and multiple tumor microenvironmental responsiveness.