Antitumor activity of folate receptor-targeted liposomal doxorubicin in a KB oral carcinoma murine xenograft model.
OBJECTIVE
The expression of folate receptor (FR) is amplified in many types of human cancers. Previously, FR-targeted liposomal doxorubicin (f-L-DOX) has been shown to exhibit superior and selective cytotoxicity against FR(+) tumor cells in vitro compared to nontargeted liposomal doxorubicin (L-DOX). This study further investigates f-L-DOX for its antitumor efficacy in vivo using a murine tumor xenograft model.


METHODS
F-L-DOX composed of DSPC/cholesterol/PEG-DSPE/ folate-PEG-DSPE (65:31:3.5:0.5, mole/mole) was prepared by polycarbonate membrane extrusion followed by remote loading of DOX. Athymic mice on a folate-free diet were engrafted with FR(+) KB cells. Two weeks later, these mice were treated with f-L-DOX, L-DOX, or free DOX in a series of six injections (given intraperitoneally on every fourth day at 10 mg/kg DOX) and monitored for tumor growth and animal survival. The plasma clearance profiles of the DOX formulations and the effect of dietary folate on plasma folate concentration were also analyzed.


RESULTS
Plasma folate level remained in the physiologic range relative to that in humans. F-L-DOX exhibited an extended systemic circulation time similar to that of L-DOX. Mice that received f-L-DOX showed greater tumor growth inhibition and a 31% higher (p < 0.01) increase in lifespan compared to those that received L-DOX. Meanwhile, free DOX given at the same dose resulted in significant toxicity and was less effective in prolonging animal survival.


CONCLUSIONS
FR-targeted liposomes are a highly efficacious vehicle for in vivo delivery of anticancer agents and have potential application in the treatment of FR(+) solid tumors.
Pan
Xing Q
XQ
Division of Pharmaceutics, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, USA.
Wang
Huaqing
H
Lee
Robert J
RJ
D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy*; D002352:Carrier Proteins / Q000096:biosynthesis*; D004317:Doxorubicin / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D005470:Fluorometry; D058973:Folate Receptors, GPI-Anchored; D005492:Folic Acid / Q000378:metabolism; D006801:Humans; D007274:Injections, Intraperitoneal; D007624:KB Cells; D008081:Liposomes; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009062:Mouth Neoplasms; D009368:Neoplasm Transplantation; D011956:Receptors, Cell Surface; D016019:Survival Analysis; D013997:Time Factors; D023041:Xenograft Model Antitumor Assays
D000970:Antineoplastic Agents; D002352:Carrier Proteins; D058973:Folate Receptors, GPI-Anchored; D008081:Liposomes; D011956:Receptors, Cell Surface; D004317:Doxorubicin; D005492:Folic Acid