Paclitaxel antitumor effect improvement in lung cancer and prevention of the painful neuropathy using large pegylated cationic liposomes.

Paclitaxel (PTX), a drug widely used in lung cancer, has serious limitations including the development of peripheral neurotoxicity, which may lead to treatment discontinuation and therapy failure. The transport of PTX in large cationic liposomes could avoid this undesirable effect, improving the patient's prognosis. PTX was encapsulated in cationic liposomes with two different sizes, MLV (180-200 nm) and SUV (80-100 nm). In both cases, excellent biocompatibility and improved internalization and antitumor effect of PTX were observed in human and mice lung cancer cells in culture, multicellular spheroids and cancer stem cells (CSCs). In addition, both MLV and SUV with a polyethylene glycol (PEG) shell, induced a greater tumor volume reduction than PTX (56.4 % and 57.1 % vs. 36.7 %, respectively) in mice. Interestingly, MLV-PEG-PTX did not induce either mechanical or heat hypersensitivity whereas SUV-PEG-PTX produced a similar response to free PTX. Analysis of PTX distribution showed a very low concentration of the drug in the dorsal root ganglia (DRG) with MLV-PEG-PTX, but not with SUV-PEG-PTX or free PTX. These results support the hypothesis that PTX induces peripheral neuropathy by penetrating the endothelial fenestrations of the DRG (80-100 nm, measured in mice). In conclusion, our larger liposomes (MLV-PEG-PTX) not only showed biocompatibility, antitumor activity against CSCs, and in vitro and in vivo antitumor effect that improved PTX free activity, but also protected from PTX-induced painful peripheral neuropathy. These advantages could be used as a new strategy of lung cancer chemotherapy to increase the PTX activity and reduce its side effects.