Glucose-receptor MR imaging of tumors: study in mice with PEGylated paramagnetic niosomes.
OBJECTIVE
To evaluate a magnetic resonance (MR) imaging contrast agent for tumor detection based on paramagnetic nonionic vesicles (niosomes) bearing polyethylene glycol (PEG) and glucose conjugates for the targeting of overexpressed glucose receptors.


METHODS
Four gadobenate dimeglumine-loaded niosome preparations including nonconjugated niosomes, niosomes bearing glucose conjugates (N-palmitoyl glucosamine [NPG]), niosomes bearing PEG 4400, and niosomes bearing both PEG and NPG were tested. In vitro cellular uptake was measured at electron paramagnetic resonance (EPR) after incubation with human prostate carcinoma, PC3, cells. In vivo distribution was studied at MR imaging 6, 12, and 24 hours after injection, with assessment of tumor, brain, liver, and muscle signal intensity (SI) in 49 mice bearing PC3 cells. Efficiency of targeted contrast agents was assessed with tumor-to-muscle contrast-to-noise ratio (CNR). Testing for differences was performed with analysis of variance followed by a posteriori Fisher test.


RESULTS
In vitro, gadolinium could be detected at EPR only in cell pellets incubated with niosomes bearing glucose conjugates or niosomes bearing both glucose conjugates and PEG (4.9. 10(-15) and 4.5. 10(-15) mol gadolinium per PC3 cell). In vivo, marked predominant tumor enhancement was demonstrated 24 hours after injection of glycosylated PEG niosomes (P <.01); no significant differences were observed following injection of nonconjugated niosomes, glycosylated niosomes, or PEG 4400 niosomes. Twenty-four hours after injection, sole presence of NPG or PEG 4400 on the surface of the niosome led to higher tumor-to-muscle CNR than that observed after injection of nonconjugated niosomes (CNR of 3.3 +/- 0.7 [SD], 3.4 +/- 2.2, and 0 +/- 1.9). Combination of NPG and PEG led to even higher tumor-to-muscle CNR (6.3 +/- 2.2).


CONCLUSIONS
Combination of PEG and glucose conjugates on the surface of niosomes significantly improved tumor targeting of an encapsulated paramagnetic agent assessed with MR imaging in a human carcinoma xenograft model.
Luciani
Alain
A
Radiology Department, Hôpital Européen Georges Pompidou, INSERM U494, LRI, Faculté Necker, 20 Rue Leblanc, 75015 Paris, France.
Olivier
Jean-Christophe
JC
Clement
Olivier
O
Siauve
Nathalie
N
Brillet
Pierre-Yves
PY
Bessoud
Bertrand
B
Gazeau
Florence
F
Uchegbu
Ijeoma F
IF
Kahn
Edmond
E
Frija
Guy
G
Cuenod
Charles A
CA
D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis / Q000097:blood; D001921:Brain / Q000378:metabolism; D003287:Contrast Media / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics; D004195:Disease Models, Animal; D004578:Electron Spin Resonance Spectroscopy; D008099:Liver / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D008536:Meglumine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism / Q000493:pharmacokinetics; D051379:Mice; D008819:Mice, Nude; D009374:Neoplasms, Experimental / Q000175:diagnosis* / Q000378:metabolism*; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics; D011092:Polyethylene Glycols / Q000378:metabolism / Q000493:pharmacokinetics; D011856:Radiographic Image Enhancement; D011956:Receptors, Cell Surface / Q000096:biosynthesis*; D013501:Surface-Active Agents / Q000378:metabolism / Q000493:pharmacokinetics; D013997:Time Factors; D014018:Tissue Distribution / Q000187:drug effects
D014408:Biomarkers, Tumor; D003287:Contrast Media; D009942:Organometallic Compounds; D011956:Receptors, Cell Surface; D013501:Surface-Active Agents; C027786:glucose receptor; C064572:gadobenic acid; D011092:Polyethylene Glycols; D008536:Meglumine