Hepatocyte targeting with Gd-EOB-DTPA: potential application for gene therapy.
OBJECTIVE
To evaluate the suitability of the liver-specific MRI contrast agent Gd-EOB-DTPA as a nonviral vector for gene therapy of hepatocellular carcinoma.


METHODS
Specific uptake of Gd-EOB-DTPA was quantified by relaxometry in rat cultured hepatocytes and the hepatoma cells HepG2 and Huh7. Nonviral vectors for gene transfer were synthesized by coupling Gd-EOB-DTPA to polyethyleneimine or polylysine as DNA condensing agents, and their efficiency was studied using beta-galactosidase (lacZ) as the reporter gene.


RESULTS
Gd-EOB-DTPA was specifically taken up by rat cultured hepatocytes (4.32 vs. 1.08 mmol/L in nonhepatocyte control cells) but not by the hepatoma cells; this uptake was concentration-dependently inhibited by Bromsulphtalein. Polycation linkages were achieved with yields of 0.9 Gd-EOB-DTPA molecule per polyethyleneimine molecule and 10 Gd-EOB-DTPA molecules per polylysine molecule. Incubating the cells with plasmids containing lacZ reporter gene and polyethyleneimine-Gd-EOB-DTPA resulted in a few blue (transfected) cells, whereas no blue cells were observed on incubation with polylysine-Gd-EOB-DTPA.


CONCLUSIONS
Gd-EOB-DTPA is taken up by normal hepatocytes but not by HepG2 and Huh7 cells, probably because of the lack of the organic anion transporter in these hepatoma cells. The Gd-EOB-DTPA polycation conjugates, such as polyethyleneimine-Gd-EOB-DTPA, could serve as transfer vectors of interest for gene targeting imagery at the early stage of hepatocarcinogenesis. However, the transfer efficiency of such conjugates is low and requires improvement.
Lewin
M
M
Laboratoire d'Imagerie, Unité Inserm 494, Faculty of Medecine Necker, Paris, France.
Clément
O
O
Belguise-Valladier
P
P
Tran
L
L
Cuénod
C A
CA
Siauve
N
N
Frija
G
G
D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy*; D003287:Contrast Media / Q000627:therapeutic use*; D019786:Gadolinium DTPA / Q000627:therapeutic use*; D015316:Genetic Therapy / Q000379:methods*; D022781:Hepatocytes; D008113:Liver Neoplasms / Q000188:drug therapy*; D051381:Rats; D014162:Transfection; D014407:Tumor Cells, Cultured
D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA