Preparation, therapeutic efficacy and intratumoral localization of targeted daunorubicin liposomes conjugating folate-PEG-CHEMS.

Folate polyethylene glycol-cholesterol hemisuccinate (folate-PEG-CHEMS) is a novel folate ligand firstly synthesized by our group and demonstrated good stability and potential targeting results on KB cells in vitro. The current study further explored endocytosis mechanisms of liposomes via folate receptor on L1210JF cells and assessed targeted therapeutic efficacy of folate-PEG-CHEMS anchored liposomes loading daunorubicin (F-L-DNR) in vivo. Folate-PEG-CHEMS was synthesized by a modified method. The liposome properties, cell cytotoxicity, intracellular and intratumoral localization, and therapeutic efficacy on a murine tumor model bearing L1210JF cells were evaluated. High encapsulation efficiency (95.1%±1.5%) and appropriate particle size (76.0±35.5nm) and zeta potential (-12.83±1.36mV) were achieved for F-L-DNR. IC(50) of F-L-DNR on L1210JF cells was 2-3-folds lower than that of non-targeted liposomal daunorubicin (L-DNR). Anticancer efficacy on L1210JF tumor model indicated that mice survival time of F-L-DNR group at doses of 5mg/kg and 10mg/kg was significantly longer than that of L-DNR or free DNR. Confocal fluorescence photographs of F-L-DNR indicated enhanced endocytosis of liposomes via folate receptor on L1210JF cells, prolonged retaining time in tumors and improved drug release in the tumor site at 24h post intravenous injection of F-L-DNR. In conclusion, folate-PEG-CHEMS is an effective ligand for folate-targeted daunorubicin liposomes to achieve increased drug release in tumor and therapeutic efficacy.