Although combinational anticancer chemotherapies have been proven to improve the life expectancy of patients in the clinic, their full potential is severely limited by the additive toxicities of the drug molecules. Targeted drug delivery systems could alleviate this major limitation by the design of nanocarriers that can cocarry multiple drug molecules in order to augment drug synergism at the site of interest while reducing the systemic side effects. In this study, we report on a thermoresponsive polymer-coated liposome nanocarrier that is capable to cocarry two potent anticancer drugs and release them via a thermally triggered mechanism. A synthetic polymer ([poly(diethylene glycol) methacrylate-co-poly(oligoethylene glycol) methacrylate]-b-poly(2-ethylhexyl) methacrylate) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and was used as a thermoresponsive polymer coating shell on thermosensitive liposome carriers. The formulations were tested in vitro against two pancreatic cancer cell lines, MiaPaCa-2 and BxPC-3, and their cytotoxic potency was studied with respect to their targeted release properties as well as their biological interactions with cellular organelles. The polymer-modified liposomes (PMTLs) could cocarry and release Gemcitabine (Gem) and cisplatin (Cis) in a thermally controlled rate and were also found to exhibit specific hydrophobic interactions with the cell membranes above the temperature transition of the formulations. In addition, the nanocarriers were found to induce more than 10-fold improvement of the IC50 of both drugs, either as monotherapies or in combination, in both cell lines tested, in a temperature dependent manner. The proposed formulations constitute a potent nanomedicinal approach for the codelivery of multiple drug molecules and could find potential uses as thermally triggered drug delivery systems for precision medicine and oncology and also as modulators of drug efficacy at the cellular level owing to their unique interactions with the cell membranes.
Keywords: cisplatin; combinational therapy; gemcitabine; pancreatic cancer; polymer; synergistic effect; targeted delivery; thermosensitive liposomes.