RGD-based strategies for improving antitumor activity of paclitaxel-loaded liposomes in nude mice xenografted with human ovarian cancer.

Tumor-targeting drug delivery systems are being the ideal carrier for systemic administration of antiproliferative drugs. RGD peptide (arginine-glycine-aspartic acid) modified liposomes containing paclitaxel (RGD-SSL-PTX). The arginine-glycine-aspartic acid tripeptide (RGD) modified sterically stabilized liposomes (SSL) containing paclitaxel (PTX) (RGD-SSL-PTX), which could increase targeting to tumor by binding with the integrin receptors overexpressed on tumor cells. The encapsulation efficiency was more than 90% and the mean particle size was of 120 nm with a narrow size distribution. It was indicated that significant cytotoxicity (3.5 times lower IC(50)) was found in the SKOV-3 human ovarian cancer cells treated with RGD-SSL-PTX preparation, as well as the intracellular uptake of liposomes (a 6.21-fold increase in fluorescence intensity), when compared to those of non-targeted liposomes (SSL). For in vivo antitumor activity, it was shown in the present study that RGD-SSL-PTX preparation had the strongest tumor growth inhibition among the test formulations (P < 0.05) in BALB/c nude mice xenografted with SKOV-3 solid tumor. Meanwhile, there was no significant change in the body weight of the animals treated with RGD-SSL-PTX for intravenous injection at a dose of 12.5 mg/kg. It was suggested that the RGD-SSL-PTX preparation might have a great advantage over present-day chemotherapy with Taxol in curing those tumors overexpressing integrin receptors.